FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Backes, H Neubauer, FM Dougherty, MK Achilleos, N Andre, N Arridge, CS Bertucci, C Jones, GH Khurana, KK Russell, CT Wennmacher, A AF Backes, H Neubauer, FM Dougherty, MK Achilleos, N Andre, N Arridge, CS Bertucci, C Jones, GH Khurana, KK Russell, CT Wennmacher, A TI Titan's magnetic field signature during the first Cassini encounter SO SCIENCE LA English DT Article ID MHD MODEL; IONOSPHERE; MAGNETOSPHERE; SIMULATION; SATURN AB The magnetic field signature obtained by Cassini during its first close encounter with Titan on 26 October 2004 is presented and explained in terms of an advanced model. Titan was inside the saturnian magnetosphere. A magnetic field minimum before closest approach marked Cassini's entry into the magnetic ionopause layer. Cassini then left the northern and entered the southern magnetic tail lobe. The magnetic field before and after the encounter was approximately constant for &SIM; 20 Titan radii, but the field orientation changed exactly at the location of Titan's orbit. No evidence of an internal magnetic field at Titan was detected. C1 Univ Cologne, Inst Geophys & Meteorol, D-50678 Cologne, Germany. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2AZ, England. Univ Toulouse 3, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Backes, H (reprint author), Univ Cologne, Inst Geophys & Meteorol, Albertus Magnus Pl, D-50678 Cologne, Germany. EM backes@geo.uni-koeln.de RI Achilleos, Nicholas/C-1647-2008; Arridge, Christopher/A-2894-2009; Jones, Geraint/C-1682-2008; OI Jones, Geraint/0000-0002-5859-1136; Russell, Christopher/0000-0003-1639-8298; Arridge, Christopher/0000-0002-0431-6526; Bertucci, Cesar/0000-0002-2540-5384; Achilleos, Nicholas/0000-0002-5886-3509 NR 19 TC 100 Z9 100 U1 0 U2 7 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 13 PY 2005 VL 308 IS 5724 BP 992 EP 995 DI 10.1126/science.1109763 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 927JR UT WOS:000229190700037 PM 15890875 ER PT J AU Dutta, PK Frank, M Hunter, GW George, M AF Dutta, PK Frank, M Hunter, GW George, M TI Reactively sputtered titania films as high temperature carbon monoxide sensors SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE gas sensing; thick film sensors ID OXIDE THIN-FILMS; GAS-SENSING APPLICATIONS; CO; MICROSTRUCTURE; SENSITIVITY AB Sputtered films of titania have been explored for sensing of carbon monoxide (CO) at 550&DEG; C. Film thickness was varied from 24 to 1000 nm by varying the sputtering time. The films were amorphous as prepared and converted to rutile upon thermal treatment. Highest sensor sensitivity, as measured by the resistance change of the film upon exposure to CO was noted for the &SIM; 240 nm film, and characterization focused on this film. Microstructure studies using electron microscopy show that the film was dense, with grain sizes of rutile of &SIM; 20 nm. Atomic force microscopy showed considerable surface roughness. The &SIM; 240 nm sputtered films exhibited higher sensitivity (factor of 3) as compared to optimized porous films made with commercially available anatase particles. © 2004 Elsevier B.V. All rights reserved. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Ohio State Univ, Ctr Ind Sensors & Measurements, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Alabama, Dept Chem, Huntsville, AL 35899 USA. RP Dutta, PK (reprint author), Ohio State Univ, Dept Chem, 120 W 18th Ave, Columbus, OH 43210 USA. EM dutta@chemistry.ohio-state.edu NR 20 TC 19 Z9 19 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD MAY 13 PY 2005 VL 106 IS 2 BP 810 EP 815 DI 10.1016/j.snb.2004.09.036 PG 6 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 924HG UT WOS:000228969100045 ER PT J AU Ricca, A Bauschlicher, CW AF Ricca, A Bauschlicher, CW TI Effect of packing and tilt on the rotational barriers of an amino, nitro-substituted phenylene ethynylene trimer SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID AU(111) SURFACE; MONOLAYERS AB Rotational potentials are computed for heptamers and nonamers of an amino, nitro-substituted phenylene ethynylene trimer molecule. A herringbone and a parallel-slipped packing arrangement are considered. The effect of tilting the molecules with respect to the surface as well as the effect of the gold support are also taken into account. The herringbone structure with the molecules perpendicular to the surface has a low rotational barrier (2 kcal/mol). Tilting the molecules by 30&DEG; increases the rotational barriers significantly (16 kcal/mol). The parallel-slipped structure has rotational barriers of 7 kcal/mol. Including the effect of the gold support increases the rotational barriers for tilted molecules but has little effect on perpendicular molecules. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Ricca, A (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 12 PY 2005 VL 109 IS 18 BP 9059 EP 9065 DI 10.1021/jp045572a PG 7 WC Chemistry, Physical SC Chemistry GA 924MM UT WOS:000228982900075 PM 16852078 ER PT J AU Vestrand, WT Wozniak, PR Wren, JA Fenimore, EE Sakamoto, T White, RR Casperson, D Davis, H Evans, S Galassi, M McGowan, KE Schier, JA Asa, JW Barthelmy, SD Cummings, JR Gehrels, N Hullinger, D Krimm, HA Markwardt, CB McLean, K Palmer, D Parsons, A Tueller, J AF Vestrand, WT Wozniak, PR Wren, JA Fenimore, EE Sakamoto, T White, RR Casperson, D Davis, H Evans, S Galassi, M McGowan, KE Schier, JA Asa, JW Barthelmy, SD Cummings, JR Gehrels, N Hullinger, D Krimm, HA Markwardt, CB McLean, K Palmer, D Parsons, A Tueller, J TI A link between prompt optical and prompt gamma-ray emission in gamma-ray bursts SO NATURE LA English DT Article ID EARLY AFTERGLOW; GRB-021211; DISCOVERY; RADIATION; RAPTOR; SKY AB The prompt optical emission that arrives with the gamma-rays from a cosmic gamma-ray burst (GRB) is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta's interactions with the surroundings(1-5). Until now, only GRB 990123 had been detected(6) at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma-ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta's collision with surrounding material. Here we report prompt optical emission from GRB 041219a. It is variable and correlated with the prompt gamma-rays, indicating a common origin for the optical light and the gamma-rays. Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine. The correlated optical emission is a direct probe of the jet isolated from the medium. The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium. C1 Los Alamos Natl Lab, Space Sci & Applicat Grp, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Pilot Grp, Unit C, Monrovia, CA 91016 USA. RP Vestrand, WT (reprint author), Los Alamos Natl Lab, Space Sci & Applicat Grp, ISR-1,MS-D466, Los Alamos, NM 87545 USA. EM vestrand@lanl.gov RI Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; Barthelmy, Scott/D-2943-2012; Parsons, Ann/I-6604-2012 NR 30 TC 150 Z9 152 U1 0 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 12 PY 2005 VL 435 IS 7039 BP 178 EP 180 DI 10.1038/nature03515 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 924ZO UT WOS:000229021100032 PM 15889084 ER PT J AU Blake, CH Bloom, JS Starr, DL Falco, EE Skrutskie, M Fenimore, EE Duchene, G Szentgyorgyi, A Hornstein, S Prochaska, JX McCabe, C Ghez, A Konopacky, Q Stapelfeldt, K Hurley, K Campbell, R Kassis, M Chaffee, F Gehrels, N Barthelmy, S Cummings, JR Hullinger, D Krimm, HA Markwardt, CB Palmer, D Parsons, A McLean, K Tueller, J AF Blake, CH Bloom, JS Starr, DL Falco, EE Skrutskie, M Fenimore, EE Duchene, G Szentgyorgyi, A Hornstein, S Prochaska, JX McCabe, C Ghez, A Konopacky, Q Stapelfeldt, K Hurley, K Campbell, R Kassis, M Chaffee, F Gehrels, N Barthelmy, S Cummings, JR Hullinger, D Krimm, HA Markwardt, CB Palmer, D Parsons, A McLean, K Tueller, J TI An infrared flash contemporaneous with the gamma-rays of GRB 041219a SO NATURE LA English DT Article ID EARLY OPTICAL-EMISSION; EARLY AFTERGLOW; BURST; RADIATION; GRB-021211; MISSION AB The explosion that results in a cosmic gamma-ray burst (GRB) is thought to produce emission from two physical processes: the central engine gives rise to the high-energy emission of the burst through internal shocking(1), and the subsequent interaction of the flow with the external environment produces long-wavelength afterglows(2-4). Although observations of afterglows(5) continue to refine our understanding of GRB progenitors and relativistic shocks, gamma-ray observations alone have not yielded a clear picture of the origin of the prompt emission(6) nor details of the central engine. Only one concurrent visible-light transient has been found(7) and it was associated with emission from an external shock. Here we report the discovery of infrared emission contemporaneous with a GRB, beginning 7.2 minutes after the onset of GRB 041219a ( ref. 8). We acquired 21 images during the active phase of the burst, yielding early multi-colour observations. Our analysis of the initial infrared pulse suggests an origin consistent with internal shocks. C1 Harvard Univ, Coll Observ, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. WM Keck Observ, Kamuela, HI 96743 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22904 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. Gemini Observ, Hilo, HI 96720 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Bloom, JS (reprint author), Harvard Univ, Coll Observ, Cambridge, MA 02138 USA. EM jbloom@astro.berkeley.edu RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; Stapelfeldt, Karl/D-2721-2012; Parsons, Ann/I-6604-2012 NR 30 TC 92 Z9 94 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 12 PY 2005 VL 435 IS 7039 BP 181 EP 184 DI 10.1038/nature03520 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 924ZO UT WOS:000229021100033 PM 15889085 ER PT J AU Colaprete, A Barnes, JR Haberle, RM Hollingsworth, JL Kieffer, HH Titus, TN AF Colaprete, A Barnes, JR Haberle, RM Hollingsworth, JL Kieffer, HH Titus, TN TI Albedo of the south pole on Mars determined by topographic forcing of atmosphere dynamics SO NATURE LA English DT Article ID GENERAL-CIRCULATION MODEL; CARBON-DIOXIDE; CAP; TES; BEHAVIOR; WAVES; ICE AB The nature of the martian south polar cap has remained enigmatic since the first spacecraft observations(1-6). In particular, the presence of a perennial carbon dioxide ice cap, the formation of a vast area of black 'slab ice' known as the Cryptic region and the asymmetric springtime retreat of the cap have eluded explanation. Here we present observations and climate modelling that indicate the south pole of Mars is characterized by two distinct regional climates that are the result of dynamical forcing by the largest southern impact basins, Argyre and Hellas. The style of surface frost deposition is controlled by these regional climates. In the cold and stormy conditions that exist poleward of 60 degrees S and extend 180 degrees in longitude west from the Mountains of Mitchel (similar to 30 degrees W), surface frost accumulation is dominated by precipitation. In the opposite hemisphere, the polar atmosphere is relatively warm and clear and frost accumulation is dominated by direct vapour deposition. It is the differences in these deposition styles that determine the cap albedo. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. NASA, Ames Res Ctr, San Jose State Univ Fdn, Moffett Field, CA 94035 USA. US Geol Survey, Astrogeol Team, Flagstaff, AZ 86001 USA. RP Colaprete, A (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. EM Anthony.Colaprete-1@nasa.gov NR 22 TC 41 Z9 41 U1 3 U2 15 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 12 PY 2005 VL 435 IS 7039 BP 184 EP 188 DI 10.1038/nature03561 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 924ZO UT WOS:000229021100034 PM 15889086 ER PT J AU Rault, DF AF Rault, DF TI Ozone profile retrieval from Stratospheric Aerosol and Gas Experiment (SAGE III) limb scatter measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OSIRIS INSTRUMENT; ODIN SATELLITE; O-3 PROFILES; ABSORPTION AB [ 1] The ability of SAGE III to retrieve the ozone vertical distribution within the atmosphere from limb scatter measurements is being investigated. The sunlight scattered by atmospheric gases and particulates ( aerosol and clouds) and the Earth's surface is measured and spectrally dispersed by the SAGE III high vertical resolution spectrometer. The spectral data are shown to contain sufficient information to retrieve ozone density from 10 km ( or cloud top) to 50 km at a resolution of about 1 km using ultraviolet and visible channels. Since SAGE III was not designed to operate in limb scatter mode, the radiance measurements are contaminated with significant stray light, and a method had to first be developed and implemented to deconvolve instrumental effects from the data. Furthermore, SAGE III has limited attitude determination capability, and tangent altitude registration has to be derived mostly from measured radiance profiles. Two retrieval algorithms were implemented to infer ozone profiles from measured radiance data: the first one is based on the wavelength triplet method, and the second one uses the multiple linear regression technique. Retrieved ozone profiles are shown for a series of cases and compared with available correlative data measured by ozone sondes, SAGE III in occultation mode, and OSIRIS. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM didier.f.rault@nasa.gov NR 24 TC 25 Z9 25 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 11 PY 2005 VL 110 IS D9 AR D09309 DI 10.1029/2004JD004970 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 927QN UT WOS:000229211500001 ER PT J AU Alderfer, DW Herring, GC Danehy, PM Mizukaki, T Takayama, K AF Alderfer, DW Herring, GC Danehy, PM Mizukaki, T Takayama, K TI Submicrosecond temperature measurement in liquid water with laser-induced thermal acoustics SO APPLIED OPTICS LA English DT Article ID SPEED; SOUND; SPECTROSCOPY; DIFFUSIVITY; THERMOMETRY; PRESSURE AB Using laser-induced thermal acoustics, we demonstrate nonintrusive and remote sound-speed and temperature measurements in liquid water. Unsteady thermal gradients in the water sample produce fast, random laser beam misalignments, which are the primary source of uncertainty in these measurements. For water temperatures over the range 10 degrees C to 45 degrees C, the precision of a single 300-ns-duration measurement varies from 1 to 16.5 m/s for sound speed and from 0.3 degrees C to 9.5 degrees C for temperature. Averaging over 10 s (100 laser pulses) yields accuracies of 0.64 m/s and 0.45 degrees C for sound speed and temperature, respectively. (c) 2005 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Japan Def Agcy, Res Ctr 1, Tech Res & Dev Inst, Tokyo 1538630, Japan. Tohoku Univ, Inst Fluid Sci, Shock Wave Res Ctr, Sendai, Miyagi 9808577, Japan. RP Alderfer, DW (reprint author), NASA, Langley Res Ctr, 18 Langley Blvd,Mail Stop 493, Hampton, VA 23681 USA. EM david.w.alderfer@nasa.gov NR 21 TC 5 Z9 5 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 10 PY 2005 VL 44 IS 14 BP 2818 EP 2826 DI 10.1364/AO.44.002818 PG 9 WC Optics SC Optics GA 925IN UT WOS:000229046900016 PM 15943334 ER PT J AU Hoge, FE Lyon, PE Wright, CW Swift, RN Yungel, JK AF Hoge, FE Lyon, PE Wright, CW Swift, RN Yungel, JK TI Chlorophyll biomass in the global oceans: airborne lidar retrieval using fluorescence of both chlorophyll and chromophoric dissolved organic matter SO APPLIED OPTICS LA English DT Article ID INHERENT OPTICAL-PROPERTIES; PHOTOCHEMICAL CHARACTERISTICS; ABSORPTION-COEFFICIENT; LASER FLUOROSENSOR; COLOR MEASUREMENT; PROBE TECHNIQUE; PHYTOPLANKTON; PIGMENTS; MODEL; ATTENUATION AB For three decades airborne laser-induced fluorescence has demonstrated value for chlorophyll biomass retrieval in wide-area oceanic field experiments, satellite validation, and algorithm development. A new chlorophyll biomass retrieval theory is developed using laser-induced and water Raman normalized fluorescence of both (a) chlorophyll and (b) chromophoric dissolved organic matter (CDOM). This airborne lidar retrieval theory is then independently confirmed by chlorophyll biomass obtained from concurrent (1) ship-cruise retrievals, (2) satellite inherent optical property (IOP) biomass retrievals, and (3) satellite standard band-ratio chlorophyll biomass retrievals. The new airborne lidar chlorophyll and CDOM fluorescence-based chlorophyll biomass retrieval is found to be more robust than prior lidar methods that used chlorophyll fluorescence only. Future research is recommended to further explain the underlying influence of CDOM on chlorophyll production. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EG & G Inc, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EM frank.hoge@nasa.gov; lyon@osb.off.nasa.gov; wright@osb.off.nasa.gov; swift@osb.wff.nasa.gov NR 25 TC 11 Z9 11 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 10 PY 2005 VL 44 IS 14 BP 2857 EP 2862 DI 10.1364/AO.44.002857 PG 6 WC Optics SC Optics GA 925IN UT WOS:000229046900021 PM 15943339 ER PT J AU Vasilkov, AP Herman, JR Ahmad, Z Kahru, M Mitchell, BG AF Vasilkov, AP Herman, JR Ahmad, Z Kahru, M Mitchell, BG TI Assessment of the ultraviolet radiation field in ocean waters from space-based measurements and full radiative-transfer calculations SO APPLIED OPTICS LA English DT Article ID ABSORPTION-SPECTRUM; NATURAL-WATERS; SCATTERING; NM; PENETRATION AB (quantitative assessment of the UV effects on aquatic ecosystems requires an estimate of the in-water radiation field. Actual ocean UV reflectances are needed for improving the total ozone retrievals from the total ozone mapping spectrometer (TOMS) and the ozone monitoring instrument (OMI) flown on NASA's Aura satellite. The estimate of underwater UV radiation can be done on the basis of measurements from the TOMS/OMI and full models of radiative transfer (RT) in the atmosphere-ocean system. The Hydrolight code, modified for extension to the UV, is used for the generation of look-up tables for in-water irradiances. A look-up table for surface radiances generated with a full RT code is input for the Hydrolight simulations. A model of seawater inherent optical properties (IOPs) is an extension of the Case 1 water model to the UV. A new element of the IOP model is parameterization of particulate matter absorption based on recent in situ data. A chlorophyll product from ocean color sensors is input for the IOP model. Verification of the in-water computational scheme shows that the calculated diffuse attenuation coefficient K-d is in good agreement with the measured K-d. (c) 2005 Optical Society of America. C1 Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci & Data Syst Inc, Silver Spring, MD 20906 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Vasilkov, AP (reprint author), Sci Syst & Applicat Inc, 10210 Greenbelt Rd, Lanham, MD 20706 USA. EM alexander_vassilkov@ssaihq.com OI Herman, Jay/0000-0002-9146-1632 NR 27 TC 15 Z9 15 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 10 PY 2005 VL 44 IS 14 BP 2863 EP 2869 DI 10.1364/AO.44.002863 PG 7 WC Optics SC Optics GA 925IN UT WOS:000229046900022 PM 15943340 ER PT J AU Fegan, SJ Badran, HM Bond, IH Boyle, PJ Bradbury, SM Buckley, JH Carter-Lewis, DA Catanese, M Celik, O Cui, W Daniel, M D'Vali, M Perez, IDC Duke, C Falcone, A Fegan, DJ Finley, JP Fortson, LF Gaidos, JA Gammell, S Gibbs, K Gillanders, GH Grube, J Hall, J Hall, TA Hanna, D Hillas, AM Holder, J Horan, D Jarvis, A Jordan, M Kenny, GE Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krawczynski, H Krennrich, F Lang, MJ Le Bohec, S Lessard, RW Linton, E Lloyd-Evans, J Milovanovic, A McEnery, J Moriarty, P Mukherjee, R Muller, D Nagai, T Nolan, S Ong, RA Pallassini, R Petry, D Power-Mooney, B Quinn, J Quinn, M Ragan, K Rebillot, P Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Swordy, SP Syson, A Vassiliev, VV Wakely, SP Walker, G Weekes, TC Zweerink, J AF Fegan, SJ Badran, HM Bond, IH Boyle, PJ Bradbury, SM Buckley, JH Carter-Lewis, DA Catanese, M Celik, O Cui, W Daniel, M D'Vali, M Perez, IDC Duke, C Falcone, A Fegan, DJ Finley, JP Fortson, LF Gaidos, JA Gammell, S Gibbs, K Gillanders, GH Grube, J Hall, J Hall, TA Hanna, D Hillas, AM Holder, J Horan, D Jarvis, A Jordan, M Kenny, GE Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krawczynski, H Krennrich, F Lang, MJ Le Bohec, S Lessard, RW Linton, E Lloyd-Evans, J Milovanovic, A McEnery, J Moriarty, P Mukherjee, R Muller, D Nagai, T Nolan, S Ong, RA Pallassini, R Petry, D Power-Mooney, B Quinn, J Quinn, M Ragan, K Rebillot, P Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Swordy, SP Syson, A Vassiliev, VV Wakely, SP Walker, G Weekes, TC Zweerink, J TI A survey of unidentified egret sources at very high energies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : jets; gamma rays : observations; surveys ID GAMMA-RAY SOURCES; SOURCE 3EG J2227+6122; X-RAY; GALACTIC PLANE; LS I+61-DEGREES-303; SUPERNOVA-REMNANTS; GALAXY CLUSTERS; SAX J0635+0533; TEV ENERGIES; ERROR BOX AB The Whipple Observatory 10 m γ-ray telescope has been used to survey the error boxes of EGRET unidentified sources in an attempt to find counterparts at energies of 350 GeV and above. Twenty-one unidentified sources detected by EGRET (more than 10% of the total number) have been included in this survey. In no case is a statistically significant signal found in the EGRET error box, which implies that, at least for this sample, the γ-ray spectra of these sources steepen between 100 MeV and 350 GeV. For each EGRET source location, we list candidate associations and derive upper limits on the integral γ-ray flux above 350 GeV. C1 Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Tanta Univ, Dept Phys, Tanta, Egypt. Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Grinnell Coll, Dept Phys, Grinnell, IA 50112 USA. Natl Univ Ireland, Expt Phys Dept, Dublin 4, Ireland. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Adler Planetarium & Astron Museum, Dept Astron, Chicago, IL USA. Natl Univ Ireland, Dept Phys, Galway, Ireland. Univ Utah, High Energy Astrophys Inst, Salt Lake City, UT 84112 USA. Univ Arkansas, Dept Phys & Astron, Little Rock, AR 72204 USA. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. DePauw Univ, Dept Phys & Astron, Greencastle, IN 46135 USA. Galway Mayo Inst Technol, Sch Sci, Galway, Ireland. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Columbia Univ Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA. Cork Inst Technol, Dept Appl Phys & Instrumentat, Cork, Ireland. RP Fegan, SJ (reprint author), Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. EM sfegan@astro.ucla.edu RI McEnery, Julie/D-6612-2012; Hall, Jeter/E-9294-2015; Daniel, Michael/A-2903-2010; OI Daniel, Michael/0000-0002-8053-7910; Cui, Wei/0000-0002-6324-5772; Knapp, Johannes/0000-0003-1519-1383; Lang, Mark/0000-0003-4641-4201 NR 74 TC 28 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 638 EP 655 DI 10.1086/429123 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000013 ER PT J AU Monnier, JD Millan-Gabet, R Billmeier, R Akeson, RL Wallace, D Berger, JP Calvet, N D'Alessio, P Danchi, WC Hartmann, L Hillenbrand, LA Kuchner, M Rajagopal, J Traub, WA Tuthill, PG Boden, A Booth, A Colavita, M Gathright, J Hrynevych, M Le Mignant, D Ligon, R Neyman, C Swain, M Thompson, R Vasisht, G Wizinowich, P Beichman, C Beletic, J Creech-Eakman, M Koresko, C Sargent, A Shao, M van Belle, G AF Monnier, JD Millan-Gabet, R Billmeier, R Akeson, RL Wallace, D Berger, JP Calvet, N D'Alessio, P Danchi, WC Hartmann, L Hillenbrand, LA Kuchner, M Rajagopal, J Traub, WA Tuthill, PG Boden, A Booth, A Colavita, M Gathright, J Hrynevych, M Le Mignant, D Ligon, R Neyman, C Swain, M Thompson, R Vasisht, G Wizinowich, P Beichman, C Beletic, J Creech-Eakman, M Koresko, C Sargent, A Shao, M van Belle, G TI The near-infrared size-luminosity relations for Herbig Ae/Be disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; instrumentation : interferometers; radiative transfer; stars : formation; stars : pre-main-sequence ID Z-CANIS-MAJORIS; YOUNG STELLAR OBJECTS; INTERMEDIATE-MASS STARS; T-TAURI STARS; CIRCUMSTELLAR DISKS; KECK INTERFEROMETER; ACCRETION DISKS; AB-AURIGAE; EMISSION; SPECTROSCOPY AB We report the results of a sensitive K-band survey of Herbig Ae/Be disk sizes using the 85 m baseline Keck Interferometer. Targets were chosen to span the maximum range of stellar properties to probe the disk size dependence on luminosity and effective temperature. For most targets, the measured near-infrared sizes (ranging from 0.2 to 4 AU) support a simple disk model possessing a central optically thin (dust-free) cavity, ringed by hot dust emitting at the expected sublimation temperatures (T-s &SIM; 1000-1500 K). Furthermore, we find a tight correlation of disk size with source luminosity R &PROP; L-1/2 for Ae and late Be systems (valid over more than two decades in luminosity), confirming earlier suggestions based on lower quality data. Interestingly, the inferred dust-free inner cavities of the highest luminosity sources (Herbig B0-B3 stars) are undersized compared to predictions of the "optically thin cavity'' model, likely because of optically thick gas within the inner AU. C1 Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Lab Astrophys Grenoble, F-38400 St Martin Dheres, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Nacl Autonoma Mexico, Mexico City 04510, DF, Mexico. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Sydney, Dept Phys, Sydney, NSW 2006, Australia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Calif Assoc Res Astron, WM Keck Observ, Kamuela, HI 96743 USA. RP Monnier, JD (reprint author), Univ Michigan, Dept Astron, 941 Dennison Bldg, Ann Arbor, MI 48109 USA. EM monnier@umich.edu RI Kuchner, Marc/E-2288-2012 NR 65 TC 111 Z9 112 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 832 EP 840 DI 10.1086/429266 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000029 ER PT J AU Rol, E Wijers, RAMJ Kouveliotou, C Kaper, L Kaneko, Y AF Rol, E Wijers, RAMJ Kouveliotou, C Kaper, L Kaneko, Y TI How special are dark gamma-ray bursts: A diagnostic tool SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; gamma rays : bursts ID HIGH COLUMN DENSITY; 28 FEBRUARY 1997; OPTICAL AFTERGLOW; HOST GALAXY; ERROR BOX; BEPPOSAX; EMISSION; DISCOVERY; DUST; PROGENITORS AB We present here a comprehensive study of the optical/near-infrared (IR) upper limits for gamma-ray bursts that have an X-ray afterglow. We have extrapolated the X-ray afterglows to optical wavelengths based on the physics of the fireball blast wave model and compared these results with optical upper limits for a large sample of bursts. We find a small set of only three bursts out of a sample of 20 for which the upper limits are not compatible with their X-ray afterglow properties within the context of any blast wave model. This sparse sample does not allow us to conclusively determine the cause of this optical/near-IR deficit. Extinction in the host galaxy is a likely cause, but high redshifts and different afterglow mechanisms might also explain the deficit in some cases. We note that the three bursts appear to have higher than average gamma-ray peak fluxes. In a magnitude versus time diagram the bursts are separated from the majority of bursts with a detected optical/near-IR afterglow. However, two gamma-ray bursts with an optical afterglow ( one of which is highly reddened) also fall in this region with dark bursts, making it likely that dark bursts are at the faint end of the set of optically detected bursts, and therefore the dark bursts likely form a continuum with the bursts with a detected optical afterglow. Our work provides a useful diagnostic tool for follow-up observations for potentially dark bursts; applied to the events detected with the Swift satellite, it will significantly increase our sample of truly dark bursts and shed light upon their nature. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Osserv Astron Trieste, INAF, I-34131 Trieste, Italy. Univ Amsterdam, Astron Inst, NL-1098 SJ Amsterdam, Netherlands. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. NASA, MSFC, Huntsville, AL 35805 USA. Univ Alabama, NSSTC, Huntsville, AL 35805 USA. RP Rol, E (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. EM er45@star.le.ac.uk; rwijers@science.uva.nl; chryssa.kouveliotou@nasa.gov; lexk@science.uva.nl; yuki.kaneko@msfc.nasa.gov NR 82 TC 66 Z9 67 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 868 EP 879 DI 10.1086/429082 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000032 ER PT J AU Levan, A Nugent, P Fruchter, A Burud, I Branch, D Rhoads, J Castro-Tirado, A Gorosabel, J Ceron, JMC Thorsett, SE Kouveliotou, C Golenetskii, S Fynbo, J Garnavich, P Holland, S Hjorth, J Moller, P Pian, E Tanvir, N Ulanov, M Wijers, R Woosley, S AF Levan, A Nugent, P Fruchter, A Burud, I Branch, D Rhoads, J Castro-Tirado, A Gorosabel, J Ceron, JMC Thorsett, SE Kouveliotou, C Golenetskii, S Fynbo, J Garnavich, P Holland, S Hjorth, J Moller, P Pian, E Tanvir, N Ulanov, M Wijers, R Woosley, S TI GRB 020410: A gamma-ray burst afterglow discovered by its supernova light SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; supernovae : general ID NEAR-INFRARED OBSERVATIONS; 28 FEBRUARY 1997; HOST GALAXY; OPTICAL AFTERGLOW; DUST EXTINCTION; DARK BURSTS; NOVA 1979C; GRB 980329; ERROR BOX; SN 1998BW AB We present the discovery and monitoring of the optical transient (OT) associated with GRB 020410. The fading OT was found by Hubble Space Telescope (HST) observations taken 28 and 65 days after burst at a position consistent with the X-ray afterglow, making this the first time that the optical afterglow of a gamma-ray burst ( GRB) has been discovered by an orbiting observatory. Subsequent reexamination of early ground-based observations revealed that a faint OT was present 6 hr after burst, confirming the source association with GRB 020410. A deep nondetection after one week requires that the OT rebrightened between day 7 and day 28, and further late-time HST data taken approximately 100 days after burst imply that it is very red ( F-ν &PROP; ν(-2.7)). We compare both the flux and color of the excess with supernova models and show that the data are best explained by the presence of a Type Ib/c supernova at a redshift z &AP; 0.5, which occurred roughly coincident with the day of the GRB. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Oklahoma, Dept Phys & Astron, Norman, OK 73019 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Natl Space Sci & Technol Ctr, NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Univ Aarhus, Dept Phys & Astron, DK-8000 Aarhus, Denmark. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. NASA, Goddard Space Flight Ctr, Swift Sci Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Copenhagen, Astron Observ, Niels Bohr Inst, DK-2100 Copenhagen, Denmark. European So Observ, D-85748 Garching, Germany. Osserv Astron Trieste, I-34131 Trieste, Italy. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. Univ Amsterdam, Astron Inst, NL-1098 SJ Amsterdam, Netherlands. RP Levan, A (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. EM anl@star.le.ac.uk RI Hjorth, Jens/M-5787-2014; Ulanov, Mikhail/B-3467-2015; Golenetskii, Sergey/B-3818-2015; OI Hjorth, Jens/0000-0002-4571-2306; Ulanov, Mikhail/0000-0002-0076-5228; Thorsett, Stephen/0000-0002-2025-9613; Wijers, Ralph/0000-0002-3101-1808; Castro-Tirado, A. J./0000-0003-2999-3563; Pian, Elena/0000-0001-8646-4858 NR 77 TC 36 Z9 36 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 880 EP 888 DI 10.1086/428657 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000033 ER PT J AU Gou, LJ Meszaros, P Kallman, TR AF Gou, LJ Meszaros, P Kallman, TR TI Detectability of gamma-ray burst iron lines by Swift, Chandra, and XMM- Newton SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : miscellaneous; gamma rays : bursts; line : identification; X-rays : stars ID EMISSION-LINES; AFTERGLOW; PREDICTIONS; PROGENITORS; REFLECTION; DISCOVERY; FEATURES; UNIVERSE; EJECTA AB The rapid acquisition of positions by the upcoming Swift satellite will allow monitoring for X-ray lines in gamma-ray burst (GRB) afterglows at much earlier epochs than was previously feasible. We calculate the possible significance levels of iron-line detections as a function of source redshift and observing time after the trigger for the Swift X-Ray Telescope (XRT), Chandra ACIS, and XMM-Newton EPIC detectors. For bursts with standard luminosities, decay rates, and equivalent widths of 1 keV assumed constant starting at early source-frame epochs, Swift may be able to detect lines up to z &SIM; 1.5 with a significance of &GSIM; 3 σ for times of t &LSIM; 10(4) s. The same lines would be detectable with &GSIM; 4σ significance at z &LSIM; 6 by Chandra and at z &LSIM; 8 by XMM-Newton for times of t &LSIM; 10(5) s. For similar bursts with a variable equivalent width that peaks at 1 keV between 0.5 and 1 day in the source frame, Swift achieves the same significance level for z &SIM; 1 at t &SIM; 1 day, while Chandra reaches the previous detection significances around t &SIM; 1 - 2 days for z &SIM; 2 - 4; i.e., the line is detectable near the peak equivalent width times and undetectable at earlier or later times. For afterglows in the upper range of initial X-ray luminosity afterglows, which may also be typical of Population III bursts, similar significance levels are obtained out to substantially higher redshifts. A distinction between broad and narrow lines to better than 3 σ is possible with Chandra and XMM-Newton out to z &SIM; 2 and &SIM; 6.5, respectively, while Swift can do so up to z &SIM; 1 for standard burst parameters. A distinction between different energy centroid lines of 6.4 versus 6.7 keV ( or 6.7 vs. Cobalt 7.2 keV) is possible up to z &LSIM; 0.6, 1.2, and 2 ( z &LSIM; 1, 5, and 7.5) with Swift, Chandra, and XMM-Newton, respectively. For the higher luminosity bursts, Swift is able to distinguish at the 5 σ level between a broad and a narrow line out to z &LSIM; 5 and between a 6.7 versus a 7.2 keV line center out to z &LSIM; 5 for times of t &LSIM; 10(4) s. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Inst Adv Study, Princeton, NJ 08540 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Gou, LJ (reprint author), Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA. NR 30 TC 7 Z9 7 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 889 EP 897 DI 10.1086/428893 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000034 ER PT J AU Verner, E Bruhweiler, F Gull, T AF Verner, E Bruhweiler, F Gull, T TI The binarity of eta Carinae revealed from photoionization modeling of the spectral variability of the Weigelt blobs B and D SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; HII regions; ISM : individual (eta Carinae); line : formation; line : identification ID RAY LIGHT-CURVE; MASSIVE STARS; ULTRAVIOLET; SPECTROSCOPY; EVOLUTION; NEBULA; EJECTA; LINES; WIND; GAS AB We focus on two Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) spectra of the Weigelt blobs B and D, extending from 1640 to 10400 8, one recorded during the 1998 minimum ( 1998 March) and the other recorded in 1999 February, early in the following broad maximum. The spatially resolved spectra suggest two distinct ionization regions. One structure is the permanently low-ionization cores of the Weigelt blobs B and D, located several hundred AU from the ionizing source. Their spectra are dominated by emission from H I, [N II], Fe II, [Fe II], Ni II, [Ni II], Cr II, and Ti II. The second region, relatively diffuse in character and located between the ionizing source and the Weigelt blobs, is more highly ionized with emission from [Fe III], [ Fe IV], N III], [ Ne III], [ Ar III], [ Si III], [ S III], and He I. Through photoionization modeling, we find that the radiation field from the more massive B-star companion supports the low-ionization structure throughout the 5.54 yr period. The radiation field of an evolved O star is required to produce the higher ionization emission seen across the broad maximum. This emission region is identified with slow-moving condensations photoionized by the O star and located in the extended mass flow emanating from the B-star primary. Comparison between the models and observations reveals that the high-ionization region is physically distinct (n(H) &AP; 10(7) cm(-3) and T-e &SIM; 10(4) K) from the B and D blobs ( n(H) &AP; 10(6) cm(-3) and T-e &SIM; 7000 K). C1 Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. Univ Dist Columbia, Dept Engn Architecture & Aerosp Technol, Washington, DC 20008 USA. RP Verner, E (reprint author), Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, 200 Hannan Hall, Washington, DC 20064 USA. EM kverner@fe2.gsfc.nasa.gov; fredb@iacs.gsfcnasa.gov; theodore.r.gull@nasa.gov RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 45 TC 62 Z9 62 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 973 EP 982 DI 10.1086/429400 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000042 ER PT J AU Burrows, A Dulick, M Bauschlicher, CW Bernath, PF Ram, RS Sharp, CM Milsom, JA AF Burrows, A Dulick, M Bauschlicher, CW Bernath, PF Ram, RS Sharp, CM Milsom, JA TI Spectroscopic constants, abundances, and opacities of the TiH molecule SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : atmospheres; stars : fundamental parameters; stars : low-mass, brown dwarfs; subdwarfs ID TRANSITION-METAL HYDRIDES; ALL-SKY SURVEY; BROWN DWARF; ROTATIONAL ANALYSIS; DISCOVERY; EQUILIBRIUM; SPECTRUM; STATES; 2MASS; CRH AB Using previous measurements and quantum chemical calculations to derive the molecular properties of the TiH molecule, we obtain new values for its rovibrational constants, thermochemical data, spectral line lists, line strengths, and absorption opacities. Furthermore, we calculate the abundance of TiH in M and L dwarf atmospheres and conclude that it is much higher than previously thought. We find that the TiH/TiO ratio increases strongly with decreasing metallicity, and at high temperatures can exceed unity. We suggest that, particularly for subdwarf L and M dwarfs, spectral features of TiH near &SIM; 0.52 and 0.94 μ m and in the H band may be more easily measurable than heretofore thought. The recent possible identification in the L subdwarf 2MASS J0532 of the 0.94 μ m feature of TiH is in keeping with this expectation. We speculate that looking for TiH in other dwarfs and subdwarfs will shed light on the distinctive titanium chemistry of the atmospheres of substellar-mass objects and the dimmest stars. C1 Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Natl Solar Observ, Tucson, AZ 85726 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. RP Burrows, A (reprint author), Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. EM burrows@zenith.as.arizona.edu; dulick@noao.edu; charles.w.bauschlicher@nasa.gov; bernath@uwaterloo.ca; rram@u.arizona.edu; csharp@as.arizona.edu; milsom@physics.arizona.edu RI Bernath, Peter/B-6567-2012 OI Bernath, Peter/0000-0002-1255-396X NR 39 TC 29 Z9 29 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP 988 EP 1002 DI 10.1086/429366 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NG UT WOS:000228916000044 ER PT J AU Bhardwaj, A Elsner, RF Waite, JH Gladstone, GR Cravens, TE Ford, PG AF Bhardwaj, A Elsner, RF Waite, JH Gladstone, GR Cravens, TE Ford, PG TI Chandra observation of an X-ray flare at saturn: Evidence of direct solar control on Saturn's disk X-ray emissions SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Saturn); scattering; Sun : flares; Sun : X-rays, gamma rays; X-rays : general ID JUPITER; EARTH; NEPTUNE; PLANETS; AURORAE; URANUS AB Saturn was observed by Chandra ACIS-S on 2004 January 20 and 26 - 27 for one full Saturn rotation (10.7 hr) at each epoch. We report here the first observation of an X-ray flare from Saturn's nonauroral (low-latitude) disk, which is seen in direct response to an M6-class flare emanating from a sunspot that was clearly visible from both Saturn and Earth. Saturn's disk X-ray emissions are found to be variable on timescales of hours to weeks to months and are correlated with solar 10.7 cm flux. Unlike Jupiter, X-rays from Saturn's polar ( auroral) region have characteristics similar to those from its disk. This report, combined with earlier studies, establishes that disk X-ray emissions of the giant planets Saturn and Jupiter are directly regulated by processes happening on the Sun. We suggest that these emissions could be monitored to study X-ray flaring from solar active regions when they are on the far side and not visible to near-Earth space weather satellites. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. SW Res Inst, San Antonio, TX 78228 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. RP Bhardwaj, A (reprint author), NASA, George C Marshall Space Flight Ctr, NSSTC-XD12,320 Sparkman Dr, Huntsville, AL 35812 USA. EM anil.bhardwaj@msfc.nasa.gov; ron.elsner@msfc.nasa.gov; hunterw@umich.edu; randy.gladstone@swri.org; cravens@ku.edu; pgf@space.mit.edu OI Bhardwaj, Anil/0000-0003-1693-453X NR 30 TC 24 Z9 24 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP L121 EP L124 DI 10.1086/430521 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NK UT WOS:000228916400015 ER PT J AU McIntosh, SW Leamon, RJ AF McIntosh, SW Leamon, RJ TI Is there a chromospheric footprint of the solar wind? SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar-terrestrial relations; solar wind; Sun : atmospheric motions; Sun : chromosphere ID EQUATORIAL CORONAL HOLE; MAGNETIC-FIELD; SOURCE REGIONS; TEMPERATURE; OUTFLOW; EXPLORER; VELOCITY; NETWORK; DRIVEN; SOHO AB We correlate the inferred structure of the solar chromospheric plasma topography with in situ solar wind velocity and composition data measured at 1 AU. Diagnostics of atmospheric "depth" in the chromosphere are made for several observing periods in active, coronal hole, and quiet-Sun regions. We demonstrate that the inferred chromospheric diagnostics correlate very strongly with solar wind velocity and inversely with the ratio of ionic oxygen (O+7/O+6) densities. These correlations suggest that the structure of the solar wind is rooted deeper in the outer solar atmosphere than has been previously considered. C1 SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. NASA, Goddard Space Flight Ctr, Commun Govt Serv Inc L3, Greenbelt, MD 20771 USA. RP SW Res Inst, Dept Space Studies, Suite 400,1050 Walnut St, Boulder, CO 80302 USA. NR 25 TC 11 Z9 11 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2005 VL 624 IS 2 BP L117 EP L120 DI 10.1086/430635 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923NK UT WOS:000228916400014 ER PT J AU Bertone, G Merritt, D AF Bertone, G Merritt, D TI Dark matter dynamics and indirect detection SO MODERN PHYSICS LETTERS A LA English DT Review DE dark matter; galactic center; astrophysics ID CENTRAL BLACK-HOLE; GAMMA-RAY; GALACTIC-CENTER; SUPERSYMMETRIC PARTICLES; NEUTRALINO ANNIHILATION; UNDERGROUND DETECTORS; MASSIVE PARTICLES; MILKY-WAY; GALAXY; LIMITS AB Non-baryonic, or "dark", matter is believed to be a major component of the total mass budget of the Universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter particles with laboratory detectors) and indirect detection (via observations of the products of dark matter self-annihilations), focusing in particular on the Galactic center, which is among the most promising targets for indirect detection studies. The gravitational potential at the Galactic center is dominated by stars and by the supermassive black hole, and the dark matter distribution is expected to evolve on sub-parsec scales due to interaction with these components. We discuss the dominant interaction mechanisms and show how they can be used to rule out certain extreme models for the dark matter distribution, thus increasing the information that can be gleaned from indirect detection searches. C1 NASA, Fermilab Particle Astrophys Ctr, Batavia, IL 60510 USA. Rochester Inst Technol, Dept Phys, Rochester, NY 14623 USA. RP NASA, Fermilab Particle Astrophys Ctr, Batavia, IL 60510 USA. EM bertone@fnal.gov; merritt@astro.rit.edu NR 141 TC 70 Z9 70 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-7323 EI 1793-6632 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD MAY 10 PY 2005 VL 20 IS 14 BP 1021 EP 1036 DI 10.1142/S0217732305017391 PG 16 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA 932QT UT WOS:000229569100001 ER PT J AU Randerson, JT van der Werf, GR Collatz, GJ Giglio, L Still, CJ Kasibhatla, P Miller, JB White, JWC DeFries, RS Kasischke, ES AF Randerson, JT van der Werf, GR Collatz, GJ Giglio, L Still, CJ Kasibhatla, P Miller, JB White, JWC DeFries, RS Kasischke, ES TI Fire emissions from C-3 and C-4 vegetation and their influence on interannual variability of atmospheric CO2 and delta(CO2)-C-13 SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID CARBON-ISOTOPE DISCRIMINATION; LAND-USE; TERRESTRIAL BIOSPHERE; C-13 DISCRIMINATION; TROPICAL FORESTS; EL-NINO; BIOMASS; SAVANNA; ECOSYSTEMS; COMBUSTION AB [ 1] Measurements of atmospheric trace gases provide evidence that fire emissions increased during the 1997/1998 El Nino event and these emissions contributed substantially to global CO2, CO, CH4, and δ(13) CO2 anomalies. Interpretation and effective use of these atmospheric observations to assess changes in the global carbon cycle requires an understanding of the amount of biomass consumed during fires, the molar ratios of emitted trace gases, and the carbon isotope ratio of emissions. Here we used satellite data of burned area, a map of C-4 canopy cover, and a global biogeochemical model to quantitatively estimate contributions of C-3 and C-4 vegetation to fire emissions during 1997 - 2001. We found that although C-4 grasses contributed to 31% of global mean emissions over this period, they accounted for only 24% of the interannual emissions anomalies. Much of the drought and increase in fire emissions during the 1997/1998 El Nino occurred in tropical regions dominated by C-3 vegetation. As a result, the δ(13) CO2 of the global fire emissions anomaly was depleted (-23.9&PTSTHOUSND;), and explained approximately 27% of the observed atmospheric decrease in δ(13) CO2 between mid-1997 and the end of 1998 ( and 61% of the observed variance in δ(13) CO2 during 1997 - 2001). Using fire emissions that were optimized in an atmospheric CO inversion, fires explained approximately 57% of the observed atmospheric δ(13) CO2 decrease between mid-1997 and the end of 1998 ( and 72% of the variance in δ(13) CO2 during 1997 - 2001). The severe drought in tropical forests during the 1997/ 1998 El Nino appeared to allow humans to ignite fires in forested areas that were normally too moist to burn. Adjacent C-4 grasses ( in woodlands and moist savannas) also burned, but emissions were limited, in part, by aboveground biomass levels that were 2 orders of magnitude smaller than C-3 biomass levels. Reduced fuel availability in some C-4 ecosystems may have led to a negative feedback on emissions. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. FAS, USDA, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. Duke Univ, Nicholas Sch Environm & Earth Sci, Durham, NC 27708 USA. NOAA, Climate Monitoring Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RP Randerson, JT (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, 3212 Croul Hall, Irvine, CA 92697 USA. EM jranders@uci.edu; guido.van.der.werf@falw.vu.nl; jim.collatz@nasa.gov; giglio@hades.gsfc.nasa.gov; still@icess.ucsb.edu; psk9@duke.edu; john.b.miller@noaa.gov; james.white@colorado.edu; rdefries@mail.umd.edu; ekasisch@geog.umd.edu RI Kasibhatla, Prasad/A-2574-2010; White, James/A-7845-2009; collatz, george/D-5381-2012 OI White, James/0000-0001-6041-4684; NR 73 TC 60 Z9 61 U1 2 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD MAY 7 PY 2005 VL 19 IS 2 AR GB2019 DI 10.1029/2004GB002366 PG 13 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 926TL UT WOS:000229145700002 ER PT J AU Heldmann, JL Toon, OB Pollard, WH Mellon, MT Pitlick, J McKay, CP Andersen, DT AF Heldmann, JL Toon, OB Pollard, WH Mellon, MT Pitlick, J McKay, CP Andersen, DT TI Formation of Martian gullies by the action of liquid water flowing under current Martian environmental conditions SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID THERMAL HISTORY; TERRESTRIAL PLANETS; MARS; EVOLUTION; ICE; CONSTRAINTS; DEPOSITS; FEATURES; SEEPAGE; CORE AB [1] Geomorphic evidence suggests that recent gullies on Mars were formed by fluvial activity. The Martian gully features are significant because their existence implies the presence of liquid water near the surface on Mars in geologically recent times. Irrespective of the ultimate source of the fluid carving the gullies, we seek to understand the behavior of this fluid after it reaches the Martian surface. We find that contrary to popular belief, the fluvially carved Martian gullies are consistent with formation conditions such as now occur on Mars, outside of the temperature-pressure stability regime of liquid water. Our model of the action of flowing pure liquid water produces the observed gully length distribution only at surface pressures and temperatures below the triple point where liquid water simultaneously boils and freezes and thus suggests that gullies were formed under conditions similar to present-day Mars. Our results suggest a typical flow rate of 30 m(3)/s to carve the gully channels. At least 0.15 km(3) has flowed across the surface of Mars to carve the gully systems observed today, and this would require an aquifer recharge rate of similar to 10(-13) - 10(-12) m/yr. The absence of gullies on Mars that are long enough to have been created above the triple point pressure argues that the atmospheric pressure has not been significantly larger than it is now the origin of the gullies. This result may imply that Mars does not possess a significant reservoir of condensed CO(2). C1 Univ Colorado, Atmospher & Space Phys Lab, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. McGill Univ, Dept Geog, Montreal, PQ H3A 2K6, Canada. Univ Colorado, Dept Geog, Boulder, CO 80309 USA. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Heldmann, JL (reprint author), NASA, Div Space Sci, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM jheldmann@mail.arc.nasa.gov RI Mellon, Michael/C-3456-2016 NR 40 TC 64 Z9 65 U1 4 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 7 PY 2005 VL 110 IS E5 AR E05004 DI 10.1029/2004JE002261 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 926TZ UT WOS:000229147400001 ER PT J AU Wielicki, BA Wong, TM Loeb, N Minnis, P Priestley, K Kandel, R AF Wielicki, BA Wong, TM Loeb, N Minnis, P Priestley, K Kandel, R TI Changes in Earth's albedo measured by satellite SO SCIENCE LA English DT Article ID CLIMATE; RADIATION; CLOUDS; CERES C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Dept Atmospher Sci, Hampton, VA 23668 USA. CNRS, Meteorol Dynam Lab, Palisades, NY USA. RP Wielicki, BA (reprint author), NASA, Langley Res Ctr, 21 Langley Blvd, Hampton, VA 23681 USA. EM b.a.wielicki@nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 7 TC 76 Z9 81 U1 3 U2 11 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 6 PY 2005 VL 308 IS 5723 BP 825 EP 825 DI 10.1126/science.1106484 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 924NW UT WOS:000228986500040 PM 15879211 ER PT J AU Pinker, RT Zhang, B Dutton, EG AF Pinker, RT Zhang, B Dutton, EG TI Do satellites detect trends in surface solar radiation? SO SCIENCE LA English DT Article ID CLOUDS; IRRADIANCE; CLIMATE; ISCCP; AEROSOLS; PROJECT; BUDGET; SCALE AB Long-term variations in solar radiation at Earth's surface (S) can affect our climate, the hydrological cycle, plant photosynthesis, and solar power. Sustained decreases in S have been widely reported from about the year 1960 to 1990. Here we present an estimate of global temporal variations in S by using the longest available satellite record. We observed an overall increase in S from 1983 to 2001 at a rate of 0.16 watts per square meter (0.10%) per year; this change is a combination of a decrease until about 1990, followed by a sustained increase. The global-scale findings are consistent with recent independent satellite observations but differ in sign and magnitude from previously reported ground observations. Unlike ground stations, satellites can uniformly sample the entire globe. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. RP Pinker, RT (reprint author), Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. RI Pinker, Rachel/F-6565-2010 NR 34 TC 250 Z9 273 U1 6 U2 45 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAY 6 PY 2005 VL 308 IS 5723 BP 850 EP 854 DI 10.1126/science.1103159 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 924NW UT WOS:000228986500047 PM 15879215 ER PT J AU Lee, T Liu, WT AF Lee, T Liu, WT TI Effects of high-frequency wind sampling on simulated mixed layer depth and upper ocean temperature SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TROPICAL PACIFIC; SURFACE WIND; BOUNDARY; FIELDS; CYCLE; MODEL AB [1] Effects of high-frequency wind sampling on a near-global ocean model are studied by forcing the model with a 12 hourly averaged wind product and its 24 hourly subsamples in separate experiments. The differences in mixed layer depth and sea surface temperature resulting from these experiments are examined, and the underlying physical processes are investigated. The 24 hourly subsampling not only reduces the high-frequency variability of the wind but also affects the annual mean wind because of aliasing. While the former effect largely impacts mid- to high-latitude oceans, the latter primarily affects tropical and coastal oceans. At mid- to high-latitude regions the subsampled wind results in a shallower mixed layer and higher sea surface temperature because of reduced vertical mixing associated with weaker high-frequency wind. In tropical and coastal regions, however, the change in upper ocean structure due to the wind subsampling is primarily caused by the difference in advection resulting from aliased annual mean wind, which varies with the subsampling time. The results of the study indicate a need for more frequent sampling of satellite wind measurement and have implications for data assimilation in terms of identifying the nature of model errors. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tlee@pacific.jpl.nasa.gov; liu@pacific.jpl.nasa.gov NR 17 TC 8 Z9 8 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 5 PY 2005 VL 110 IS C5 AR C05002 DI 10.1029/2004JC002746 PG 9 WC Oceanography SC Oceanography GA 926TW UT WOS:000229146900001 ER PT J AU Roy, S Cooper, SM Meyyappan, M Cruden, BA AF Roy, S Cooper, SM Meyyappan, M Cruden, BA TI Single component gas transport through 10 nm pores: Experimental data and hydrodynamic prediction SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE Knudsen-Smoluchoski relations; TMAC; polycarbonate membrane; hydrodynamic model; slip boundary conditions AB This paper presents experimental measurements of argon and oxygen gas flow through a 10 nm polycarbonate membrane, which are an order of magnitude higher than would be predicted by Knudsen diffusion alone, but may be described as ratified diffusion with slip (Knudsen-Smoluchoski diffusion). We also simulate the Poiseuille gas flow using a finite element based model and find that the hydrodynamic model may successfully predict Knudsen-like diffusion for Knudsen numbers as high as 10, contrary to conventional wisdom about the limitations of continuum models in the ratified regime. With the addition of slip boundary conditions, the model is able to describe the data with a similar tangential momentum accommodation coefficient (TMAC) as predicted by Knudsen-Smoluchoski diffusion. Transient measurements show that the pressure decay can be expressed by two distinct time constants, both of which indicate a faster decay than predicted by the Knudsen-Smoluchoski relations. The fact that the hydrodynamic model can successfully predict measured flow characteristics while conventional Knudsen-Smoluchoski ratified gas transport fails demonstrates that the hydrodynamic model may be extended into the nanoscale regime even at low gas density. (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Kettering Univ, Dept Mech Engn, Computat Plasma Dynam Lab, Flint, MI 48504 USA. RP Cruden, BA (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM bcruden@mail.arc.nasa.gov RI Roy, Subrata/A-7493-2009 NR 12 TC 11 Z9 11 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD MAY 5 PY 2005 VL 253 IS 1-2 BP 209 EP 215 DI 10.1016/j.memsci.2004.11.033 PG 7 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 922PU UT WOS:000228851000020 ER PT J AU Dalton, JB AF Dalton, JB TI Planetary science - Saturn's retrograde renegade SO NATURE LA English DT Editorial Material C1 NASA, Ames Res Ctr, Planetary Syst Branch, SETI Inst, Moffett Field, CA 94035 USA. RP Dalton, JB (reprint author), NASA, Ames Res Ctr, Planetary Syst Branch, SETI Inst, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM dalton@mail.arc.nasa.gov NR 0 TC 2 Z9 2 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 5 PY 2005 VL 435 IS 7038 BP 33 EP 34 DI 10.1038/435033a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 922UL UT WOS:000228864600027 PM 15875004 ER PT J AU Clark, RN Brown, RH Jaumann, R Cruikshank, DP Nelson, RM Buratti, BJ Mccord, TB Lunine, J Baines, KH Bellucci, G Bibring, JP Capaccioni, F Cerroni, P Coradini, A Formisano, V Langevin, Y Matson, DL Mennella, V Nicholson, PD Sicardy, B Sotin, C Hoefen, TM Curchin, JM Hansen, G Hibbits, K Matz, KD AF Clark, RN Brown, RH Jaumann, R Cruikshank, DP Nelson, RM Buratti, BJ Mccord, TB Lunine, J Baines, KH Bellucci, G Bibring, JP Capaccioni, F Cerroni, P Coradini, A Formisano, V Langevin, Y Matson, DL Mennella, V Nicholson, PD Sicardy, B Sotin, C Hoefen, TM Curchin, JM Hansen, G Hibbits, K Matz, KD TI Compositional maps of Saturn's moon Phoebe from imaging spectroscopy SO NATURE LA English DT Article ID WATER-ICE; ASTEROIDS; HYPERION; BELT AB The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed(1). By contrast, Saturn's regular satellites ( with prograde, low-inclination, circular orbits) probably accreted within the sub-nebula in which Saturn itself formed(2). Here we report imaging spectroscopy of Phoebe resulting from the Cassini - Huygens spacecraft encounter on 11 June 2004. We mapped ferrous-iron-bearing minerals, bound water, trapped CO2, probable phyllosilicates, organics, nitriles and cyanide compounds. Detection of these compounds on Phoebe makes it one of the most compositionally diverse objects yet observed in our Solar System. It is likely that Phoebe's surface contains primitive materials from the outer Solar System, indicating a surface of cometary origin. C1 US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Stewart Observ, Tucson, AZ 85721 USA. German Aerosp Ctr, Inst Space Sensor Technol & Planetary Explorat, D-12489 Berlin, Germany. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii Manoa, HIGP, SOEST, Honolulu, HI 96822 USA. CNR, Ist Fis Spazio Interplanetario, I-00133 Rome, Italy. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Observ Paris, F-92195 Meudon, France. Univ Nantes, Lab Planetol & Geodynam, CNRS, UMR 6112, F-44322 Nantes, France. Planetary Sci Inst NW, Corp Ctr Pasadena, Pasadena, CA 91101 USA. Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. RP Clark, RN (reprint author), US Geol Survey, Denver Fed Ctr, MS964,Box 25046, Denver, CO 80225 USA. EM rclark@usgs.gov OI Cerroni, Priscilla/0000-0003-0239-2741; Bellucci, Giancarlo/0000-0003-0867-8679; Capaccioni, Fabrizio/0000-0003-1631-4314 NR 21 TC 97 Z9 97 U1 1 U2 8 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 5 PY 2005 VL 435 IS 7038 BP 66 EP 69 DI 10.1038/nature03558 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 922UL UT WOS:000228864600036 PM 15875014 ER PT J AU Johnson, TV Lunine, JI AF Johnson, TV Lunine, JI TI Saturn's moon Phoebe as a captured body from the outer Solar System SO NATURE LA English DT Article ID SATELLITES; NEBULA; ABUNDANCES; ELEMENTS AB The orbital properties of Phoebe, one of Saturn's irregular moons, suggest that it was captured by the ringed planet's gravitational field rather than formed in situ. Phoebe's generally dark surface shows evidence of water ice(1), but otherwise the surface most closely resembles that of C-type asteroids(2) and small outer Solar System bodies such as Chiron and Pholus that are thought to have originated in the Kuiper belt(3). A close fly-by of Phoebe by the Cassini-Huygens spacecraft on 11 June 2004 ( 19 days before the spacecraft entered orbit around Saturn) provided an opportunity to test the hypothesis that this moon did not form in situ during Saturn's formation, but is instead a product of the larger protoplanetary disk or 'solar nebula'. Here we derive the rock-to-ice ratio of Phoebe using its density(4,5) combined with newly measured oxygen and carbon abundances in the solar photosphere(6,7). Phoebe's composition is close to that derived for other solar nebula bodies such as Triton and Pluto, but is very different from that of the regular satellites of Saturn, supporting Phoebe's origin as a captured body from the outer Solar System. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lunine, JI (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM jlunine@lpl.arizona.edu NR 22 TC 54 Z9 54 U1 2 U2 9 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 5 PY 2005 VL 435 IS 7038 BP 69 EP 71 DI 10.1038/nature03384 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 922UL UT WOS:000228864600037 PM 15875015 ER PT J AU Mannucci, AJ Tsurutani, BT Iijima, BA Komjathy, A Saito, A Gonzalez, WD Guarnieri, FL Kozyra, JU Skoug, R AF Mannucci, AJ Tsurutani, BT Iijima, BA Komjathy, A Saito, A Gonzalez, WD Guarnieri, FL Kozyra, JU Skoug, R TI Dayside global ionospheric response to the major interplanetary events of October 29-30, 2003 "Halloween storms" SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GREAT MAGNETIC STORM; F-REGION; ELECTRODYNAMICS AB We demonstrate extreme ionospheric response to the large interplanetary electric fields during the "Halloween'' storms that occurred on October 29 and 30, 2003. Within a few ( 2 - 5) hours of the time when the enhanced interplanetary electric field impinged on the magnetopause, dayside total electron content increases of similar to 40% and similar to 250% are observed for the October 29 and 30 events, respectively. During the Oct 30 event, similar to 900% increases in electron content above the CHAMP satellite ( similar to 400 km altitude) were observed at mid-latitudes ( +/- 30 degrees geomagnetic). The geomagnetic storm-time phenomenon of prompt penetration electric fields is a possible contributing cause of these electron content increases, producing dayside ionospheric uplift combined with equatorial plasma diffusion along magnetic field lines to higher latitudes, creating a "daytime super-fountain'' effect. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kyoto Univ, Dept Geophys, Kyoto 6068502, Japan. Inst Pesquisas Espaciais, BR-12201970 Sao Jose Dos Campos, Brazil. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Mannucci, AJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Mannucci, Anthony/A-1349-2007 OI Mannucci, Anthony/0000-0003-2391-8490 NR 19 TC 227 Z9 228 U1 2 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 4 PY 2005 VL 32 IS 12 AR L12S02 DI 10.1029/2004GL021467 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 926TJ UT WOS:000229145500001 ER PT J AU Lepping, RP Sittler, EC Mish, WH Curtis, SA Tsurutani, BT AF Lepping, RP Sittler, EC Mish, WH Curtis, SA Tsurutani, BT TI Analysis of waves in Saturn's dayside magnetosphere: Voyager 1 observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ION-CYCLOTRON WAVES; EXTREME ULTRAVIOLET OBSERVATIONS; TITANS UPPER-ATMOSPHERE; MAGNETIC-FIELD; PLASMA OBSERVATIONS; HOT PLASMA; TORUS; INSTABILITY; ENCOUNTER; PARTICLES AB [1] Magnetic field fluctuations were observed in the data of Voyager 1 on its inbound leg in Saturn's magnetosphere from about 19 to 8.4 Saturn radii, during the interval 7 17 hours before closest approach. These low-amplitude oscillations had the appearance of irregular micropulsations. The wave periods in the spacecraft frame varied between &AP; 1 and 20 min with a tendency to be inversely correlated with the field strength. An eigenfunction analysis yielding wave propagation direction as a function of frequency showed that at and near peak frequency two distinct types of waves were present, one propagating along field lines ( within 30&DEG;) usually at the higher frequencies considered, ( 4 - 14) x 10(-3) Hz, and the other propagating along (φ) over cap ( the azimuthal direction in a standard spherical coordinate system) at lower frequencies, (0.8 - 4) x 10(-3) Hz. The power spectral density ( in ( nT)(2)/ Hz) at the peaks tended to be inversely related to frequency over the full set of frequencies. An interpretation of these results is that Alfven waves are propagating along field lines at the higher frequencies with wavelengths between 1/4 and 1/2 R-S. These occur in both the mantle and plasma sheet. The waves traveling along (φ) over cap, which are observed to occur in the low-latitude plasma mantle, are apparently manifestations of rapidly corotating MHD waves with large compressional components and are probably due to the operation of the centrifugal flute instability at the plasma sheet-mantle boundary. For both types, wave absorption occurs with a high-frequency cutoff at or near the gyrofrequency of O+ ( and/or N+). Our results establish the framework for MHD waves within Saturn's outer magnetosphere, and it is expected that the Cassini mission, for which orbit insertion occurred on 1 July 2004, will add considerably to that presented here. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lepping, RP (reprint author), NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. EM edward.c.sittler@nasa.gov NR 57 TC 4 Z9 4 U1 3 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 4 PY 2005 VL 110 IS A5 AR A05201 DI 10.1029/2004JA010559 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 926UF UT WOS:000229148000002 ER PT J AU Cattrall, C Reagan, J Thome, K Dubovik, O AF Cattrall, C Reagan, J Thome, K Dubovik, O TI Variability of aerosol and spectral lidar and backscatter and extinction ratios of key aerosol types derived from selected Aerosol Robotic Network locations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SINGLE-SCATTERING ALBEDO; EUROPEAN POLLUTION OUTBREAKS; SKY RADIANCE MEASUREMENTS; INDIAN-OCEAN EXPERIMENT; WAVELENGTH RAMAN LIDAR; SOUTHERN GREAT-PLAINS; OPTICAL-PROPERTIES; SAHARAN DUST; TROPOSPHERIC AEROSOL; 6-WAVELENGTH LIDAR AB [1] The lidar (extinction-to-backscatter) ratios at 0.55 and 1.02 mu m and the spectral lidar, extinction, and backscatter ratios of climatically relevant aerosol species are computed on the basis of selected retrievals of aerosol properties from 26 Aerosol Robotic Network (AERONET) sites across the globe. The values, obtained indirectly from sky radiance and solar transmittance measurements, agree very well with values from direct observations. Low mean values of the lidar ratio, S-a, at 0.55 mu m for maritime ( 27 sr) aerosols and desert dust ( 42 sr) are clearly distinguishable from biomass burning ( 60 sr) and urban/industrial pollution ( 71 sr). The effects of nonsphericity of mineral dust are shown, demonstrating that particle shape must be taken into account in any spaceborne lidar inversion scheme. A new aerosol model representing pollution over Southeast Asia is introduced since lidar ( 58 sr), color lidar, and extinction ratios in this region are distinct from those over other urban/industrial centers, owing to a greater number of large particles relative to fine particles. This discrimination promises improved estimates of regional climate forcing by aerosols containing black carbon and is expected to be of utility to climate modeling and remote sensing communities. The observed variability of the lidar parameters, combined with current validated aerosol data products from Moderate Resolution Imaging Spectroradiometer ( MODIS), will afford improved accuracy in the inversion of spaceborne lidar data over both land and ocean. C1 Univ Arizona, Remote Sensing Grp, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Dept Elect & Comp Engn, Tucson, AZ 85721 USA. RP Univ Arizona, Remote Sensing Grp, 630 E Univ Blvd, Tucson, AZ 85721 USA. EM chris.cattrall@opt-sci.arizona.edu RI Thome, Kurtis/D-7251-2012; Dubovik, Oleg/A-8235-2009 OI Dubovik, Oleg/0000-0003-3482-6460 NR 87 TC 139 Z9 143 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 3 PY 2005 VL 110 IS D10 AR D10SA11 DI 10.1029/2004JD005124 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 926TR UT WOS:000229146300001 ER PT J AU Zhang, MH Lin, WY Klein, SA Bacmeister, JT Bony, S Cederwall, RT Del Genio, AD Hack, JJ Loeb, NG Lohmann, U Minnis, P Musat, I Pincus, R Stier, P Suarez, MJ Webb, MJ Wu, JB Xie, SC Yao, MS Zhang, JH AF Zhang, MH Lin, WY Klein, SA Bacmeister, JT Bony, S Cederwall, RT Del Genio, AD Hack, JJ Loeb, NG Lohmann, U Minnis, P Musat, I Pincus, R Stier, P Suarez, MJ Webb, MJ Wu, JB Xie, SC Yao, MS Zhang, JH TI Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LARGE-SCALE MODELS; RELAXED ARAKAWA-SCHUBERT; LAYER MIXING SCHEME; CUMULUS CONVECTION; BOUNDARY-LAYER; CLIMATE MODEL; MOIST CONVECTION; FRONTAL CLOUDS; HADLEY-CENTER; WATER-VAPOR AB [1] To assess the current status of climate models in simulating clouds, basic cloud climatologies from ten atmospheric general circulation models are compared with satellite measurements from the International Satellite Cloud Climatology Project (ISCCP) and the Clouds and Earth's Radiant Energy System (CERES) program. An ISCCP simulator is employed in all models to facilitate the comparison. Models simulated a four-fold difference in high-top clouds. There are also, however, large uncertainties in satellite high thin clouds to effectively constrain the models. The majority of models only simulated 30 - 40% of middle-top clouds in the ISCCP and CERES data sets. Half of the models underestimated low clouds, while none overestimated them at a statistically significant level. When stratified in the optical thickness ranges, the majority of the models simulated optically thick clouds more than twice the satellite observations. Most models, however, underestimated optically intermediate and thin clouds. Compensations of these clouds biases are used to explain the simulated longwave and shortwave cloud radiative forcing at the top of the atmosphere. Seasonal sensitivities of clouds are also analyzed to compare with observations. Models are shown to simulate seasonal variations better for high clouds than for low clouds. Latitudinal distribution of the seasonal variations correlate with satellite measurements at > 0.9, 0.6 - 0.9, and -0.2 - 0.7 levels for high, middle, and low clouds, respectively. The seasonal sensitivities of cloud types are found to strongly depend on the basic cloud climatology in the models. Models that systematically underestimate middle clouds also underestimate seasonal variations, while those that overestimate optically thick clouds also overestimate their seasonal sensitivities. Possible causes of the systematic cloud biases in the models are discussed. C1 SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Anal Off, Greenbelt, MD 20771 USA. CNRS, Inst Pierre Simon Laplace, Meteorol Dynam Lab, F-75252 Paris, France. Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94551 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 3J5, Canada. NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80305 USA. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. UK Met Off, Hadley Ctr Climate Predict & Res, Bracknell, Berks, England. RP Zhang, MH (reprint author), SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. EM mzhang@notes.cc.sunysb.edu RI Del Genio, Anthony/D-4663-2012; Xie, Shaocheng/D-2207-2013; Stier, Philip/B-2258-2008; Pincus, Robert/B-1723-2013; Klein, Stephen/H-4337-2016; Lohmann, Ulrike/B-6153-2009; Minnis, Patrick/G-1902-2010; OI Del Genio, Anthony/0000-0001-7450-1359; Xie, Shaocheng/0000-0001-8931-5145; Stier, Philip/0000-0002-1191-0128; Pincus, Robert/0000-0002-0016-3470; Klein, Stephen/0000-0002-5476-858X; Lohmann, Ulrike/0000-0001-8885-3785; Minnis, Patrick/0000-0002-4733-6148; Bony, Sandrine/0000-0002-4791-4438 NR 75 TC 219 Z9 223 U1 1 U2 26 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 3 PY 2005 VL 110 IS D15 AR D15S02 DI 10.1029/2004JD005021 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 926TS UT WOS:000229146500001 ER PT J AU Tyson, DS Ilhan, F Meador, MAB Smith, DD Scheiman, DA Meador, MA AF Tyson, DS Ilhan, F Meador, MAB Smith, DD Scheiman, DA Meador, MA TI Diels-Alder trapping of photochemically generated o-quinodimethane intermediates: An alternative route to photocured polymer film development SO MACROMOLECULES LA English DT Article ID BISMALEIMIDE AB Photolysis of o-methylphenyl ketones generates o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate esters for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state C-13 NMR data indicated 47-100% reaction of the bis(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T-g, and onset of decomposition, T-d, of the resulting polymer films. A statistical "design of experiments" approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. QSS Grp Inc, Lanham, MD 20706 USA. RP Meador, MA (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Michael.A.Meador@grc.nasa.go OI Meador, Mary Ann/0000-0003-2513-7372 NR 20 TC 12 Z9 12 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 3 PY 2005 VL 38 IS 9 BP 3638 EP 3646 DI 10.1021/ma048291+ PG 9 WC Polymer Science SC Polymer Science GA 921BG UT WOS:000228738600018 ER PT J AU Simonson, AB Servin, JA Skophammer, RG Herbold, CW Rivera, MC Lake, JA AF Simonson, AB Servin, JA Skophammer, RG Herbold, CW Rivera, MC Lake, JA TI Decoding the genomic tree of life SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT Colloquium on Systematics and the Origin of Species CY DEC 16-18, 2004 CL Irvine, CA SP Natl Acad Sci & Engn ID HORIZONTAL GENE-TRANSFER; CLOSEST LIVING RELATIVES; TRANSFER-RNA SYNTHETASES; WHOLE-GENOME; HYPERTHERMOPHILIC ARCHAEA; EVOLUTIONARY RELATIONSHIPS; PHYLOGENETIC ANALYSIS; EUKARYOTIC NUCLEUS; BACTERIAL GENOMES; BACILLUS-SUBTILIS AB Genomes hold within them the record of the evolution of life on Earth. But genome fusions and horizontal gene transfer (HGT) seem to have obscured sufficiently the gene sequence record such that it is difficult to reconstruct the phylogenetic tree of life. HGT among prokaryotes is not random, however. Some genes (informational genes) are more difficult to transfer than others (operational genes). Furthermore, environmental, metabolic, and genetic differences among organisms restrict HGT, so that prokaryotes preferentially share genes with other prokaryotes having properties in common, including genome size, genome G + C composition, carbon utilization, oxygen utilization/sensitivity, and temperature optima, further complicating attempts to reconstruct the tree of life. A new method of phylogenetic reconstruction based on gene presence and absence, called conditioned reconstruction, has improved our prospects for reconstructing prokaryotic evolution. It is also able to detect past genome fusions, such as the fusion that appears to have created the first eukaryote. This genome fusion between a deep branching eubacterium, possibly an ancestor of the cyanobacterium and a proteobacterium, with an archaeal eocyte (crenarchaea), appears to be the result of an early symbiosis. Given new tools and new genes from relevant organisms, it should soon be possible to test current and future fusion theories for the origin of eukaryotes and to discover the general outlines of the prokaryotic tree of life. C1 Univ Calif Los Angeles, Dept Mol Cell & Dev Biol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Mol Biol, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Human Genet, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. RP Lake, JA (reprint author), Univ Calif Los Angeles, Dept Mol Cell & Dev Biol, 242 Boyer Hall, Los Angeles, CA 90095 USA. EM Lake@mbi.ucla.edu OI Herbold, Craig/0000-0003-3479-0197 FU NHGRI NIH HHS [T32 HG002536] NR 84 TC 49 Z9 53 U1 0 U2 11 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 3 PY 2005 VL 102 SU 1 BP 6608 EP 6613 DI 10.1073/pnas.0501996102 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 925AK UT WOS:000229023700015 PM 15851667 ER PT J AU Marcinkevicius, S Qiu, YM Leon, R Ibanez, J Cusco, R Artus, L AF Marcinkevicius, S Qiu, YM Leon, R Ibanez, J Cusco, R Artus, L TI Time-resolved photoluminescence and Raman scattering of InAsSb/InP quantum dots SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL PHONONS; PHASE EPITAXY; STRAIN; GAAS; SPECTROSCOPY; LAYER AB InAsSb quantum dots (QDs) grown by metalorganic vapor phase epitaxy on In0.53Ga0.47As/InP under different TMSb/AsH3 flow ratios have been characterized by means of continuous wave and time-resolved photoluminescence (PL) as well as Raman scattering. It was found that the flow ratio has a very strong influence on the QD composition, PL peak energies, and carrier recombination times. While the samples prepared using low TMSb/AsH3 flow ratios show a bimodal character with both InAs and InAsSb QDs present, in the structures grown at high flow ratios the InAsSb QDs dominate, showing strong photoluminescence intensity, fast carrier capture and slow recombination. (c) 2005 American Institute of Physics. C1 Royal Inst Technol, Dept Microelect & Informat Technol, S-16440 Kista, Sweden. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CSIC, Inst Jaume Almera, Barcelona, Catalonia, Spain. RP Marcinkevicius, S (reprint author), Royal Inst Technol, Dept Microelect & Informat Technol, Electrum 229, S-16440 Kista, Sweden. EM sm@imit.kth.se RI Ibanez-Insa, Jordi/F-6995-2014; OI Ibanez-Insa, Jordi/0000-0002-8909-6541; Cusco, Ramon/0000-0001-9490-4884 NR 18 TC 4 Z9 4 U1 3 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 2 PY 2005 VL 86 IS 18 AR 181110 DI 10.1063/1.1900308 PG 3 WC Physics, Applied SC Physics GA 928RF UT WOS:000229288700010 ER PT J AU Richman, BA Kachanov, AA Paldus, BA Strawa, AW AF Richman, BA Kachanov, AA Paldus, BA Strawa, AW TI Novel detection of aerosols: combined cavity ring-down and fluorescence spectroscopy SO OPTICS EXPRESS LA English DT Article ID OPTICAL EXTINCTION; LASER; ABSORPTION AB High fluences inside cavity ring-down spectroscopy optical resonators lend themselves to fluorescence or nonlinear optical spectroscopy. An instrument at 488 nm was developed to measure extinction, and fluorescence of aerosols. A detection limit of 6 x 10(-9) cm-(1)Hz(-1/2) (0.6 Mm(-1)Hz(-1/2)) was achieved. The fluorescence spectral power collected from a single fluorescent microsphere was 10 to 20 pW/nm. This power is sufficient to obtain the spectrum of a single microsphere with a resolution of 10 nm and signal-to-noise ratio of &SIM; 10. The relative concentrations of two types of fluorescent microspheres were determined from a time-integrated fluorescence measurement of a mixture of both. (C) 2005 Optical Society of America. C1 Picarro Inc, Sunnyvale, CA 94085 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Richman, BA (reprint author), Picarro Inc, 4800 Oakmead Pkwy, Sunnyvale, CA 94085 USA. EM brichman@picarro.com; akachanov@picarro.com; bpaldus@picarro.com; astrawa@mail.arc.nasa.gov NR 17 TC 14 Z9 15 U1 2 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAY 2 PY 2005 VL 13 IS 9 BP 3376 EP 3387 DI 10.1364/OPEX.13.003376 PG 12 WC Optics SC Optics GA 923FW UT WOS:000228896200022 PM 19495240 ER PT J AU Mohageg, M Strekalov, DV Savchenkov, AA Matsko, AB Ilchenko, VS Maleki, L AF Mohageg, M Strekalov, DV Savchenkov, AA Matsko, AB Ilchenko, VS Maleki, L TI Calligraphic poling of Lithium Niobate SO OPTICS EXPRESS LA English DT Article ID BLUE-LIGHT GENERATION; 2ND-HARMONIC GENERATION; FERROELECTRIC DOMAINS; WAVE-GUIDE; MICROSCOPY; CRYSTALS; LINBO3 AB We demonstrate a novel technique for instituting complex and arbitrary shaped micron-scale domain patterns in LiNbO3 at room temperature. Fabrication of continuous domains as narrow as 2 mu m across and hexagonal patterns of the same order accompanied by real time visualization of the poling process are presented. (C) 2005 Optical Society of America. C1 CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, Pasadena, CA 91109 USA. RP Mohageg, M (reprint author), CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM makan.mohageg@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 24 TC 17 Z9 18 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAY 2 PY 2005 VL 13 IS 9 BP 3408 EP 3419 DI 10.1364/OPEX.13.003408 PG 12 WC Optics SC Optics GA 923FW UT WOS:000228896200025 PM 19495243 ER PT J AU Ehlmann, BL Chowdhury, J Marzullo, TC Collins, RE Litzenberger, J Ibsen, S Krauser, WR DeKock, B Hannon, M Kinnevan, J Shepard, R Grant, FD AF Ehlmann, BL Chowdhury, J Marzullo, TC Collins, RE Litzenberger, J Ibsen, S Krauser, WR DeKock, B Hannon, M Kinnevan, J Shepard, R Grant, FD TI Humans to Mars: A feasibility and cost-benefit analysis SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT International Scientific Symposium on Humans in Space CY MAY 18-22, 2003 CL Banff, CANADA SP Canadian Space Agcy DE Mars; human; mission; feasibility; technical; political ID SURFACE; CLIMATE AB Mars is a compelling astrobiological target, and a human mission would provide an opportunity to collect immense amounts of scientific data. Exploration alone, however, cannot justify the increased risk. Instead, three factors drive a human mission: economics, education, and exploration. A human mission has a unique potential to inspire the next generation of young people to enter critically needed science and engineering disciplines. A mission is economically feasible, and the research and development program put in place for a human mission would propel growth in related high-technology industries. The main hurdles are human physiological responses to 1-2 years of radiation and microgravity exposure. However, enabling technologies are sufficiently mature in these areas that they can be developed within a few decade timescale. Hence, the decision of whether or not to undertake a human mission to Mars is a political decision, and thus, educational and economic benefits are the crucial factors. © 2005 Elsevier Ltd. All rights reserved. C1 Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Univ Alberta, Sch Med, Edmonton, AB T6G 2M7, Canada. Univ Michigan, Program Neurosci, Ann Arbor, MI 48109 USA. Univ Washington, Sch Oceanog, Washington, DC USA. Stanford Univ, Dept Engn Mech, Biomed Engn Div, Stanford, CA 94305 USA. Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Oklahoma, Dept Engn Mech, Norman, OK 73019 USA. Univ Notre Dame, Dept Engn Mech, Notre Dame, IN 46556 USA. Univ New Hampshire, Dept Elect Engn, Durham, NH 03824 USA. Univ Calif Davis, Dept Geol, Davis, CA 95616 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RP Ehlmann, BL (reprint author), Campus Box 1169,1 Brooklyn Dr, St Louis, MO 63130 USA. EM bethany.ehlmann@wustl.edu NR 23 TC 6 Z9 8 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2005 VL 56 IS 9-12 BP 851 EP 858 DI 10.1016/j.actaastro.2005.01.010 PG 8 WC Engineering, Aerospace SC Engineering GA 925PA UT WOS:000229063800010 PM 15835029 ER PT J AU Uri, JJ Nygren, RW Cardenas, JA AF Uri, JJ Nygren, RW Cardenas, JA TI Lessons learned from Mir - a payload perspective SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT International Scientific Symposium on Humans in Space CY MAY 18-22, 2003 CL Banff, CANADA SP Canadian Space Agcy DE Mir; International Space Station; research AB Among the principal objectives of the Phase I NASA/Mir program were for the United States to gain experience working with an international partner, to gain working experience in long-duration space flight, and to gain working experience in planning for and executing research on a long-duration space platform. The Phase I program was to provide the US early experience prior to the construction and operation of the International Space Station (Phase 2 and 3). While it can be argued that Mir and ISS are different platforms and that programmatically Phase I and ISS are organized differently, it is also clear that many aspects of operating a long-duration research program are platform independent. This can be demonstrated by a review of lessons learned from Skylab, a US space station program of the mid-1970s, many of which were again "learned" on Mir and are being "learned" on ISS. Among these are optimum crew training strategies, on-orbit crew operations, ground support, medical operations and crew psychological support, and safety certification processes. 2005 Published by Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. Univ Space Res Assoc, Houston, TX 77058 USA. RP Uri, JJ (reprint author), NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. NR 3 TC 1 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2005 VL 56 IS 9-12 BP 877 EP 882 DI 10.1016/j.actaastro.2005.01.013 PG 6 WC Engineering, Aerospace SC Engineering GA 925PA UT WOS:000229063800013 PM 15835035 ER PT J AU Uri, JJ Haven, CP AF Uri, JJ Haven, CP TI Accomplishments in bioastronautics research aboard International Space Station SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT International Scientific Symposium on Humans in Space CY MAY 18-22, 2003 CL Banff, CANADA SP Canadian Space Agcy AB The tenth long-duration expedition crew is currently in residence aboard International Space Station (ISS), continuing a permanent human presence in space that began in October 2000. During that time, expedition crews have been operators and subjects for 18 Human Life Sciences investigations, to gain a better understanding of the effects of long-duration space flight on the crewmembers and of the environment in which they live. Investigations have been conducted to study: the radiation environment in the station as well as during extravehicular activity (EVA); bone demineralization and muscle deconditioning; changes in neuromuscular reflexes; muscle forces and postflight mobility; causes and possible treatment of postflight orthostatic intolerance; risk of developing kidney stones; changes in pulmonary function caused by long-duration flight as well as EVA; crew and crew-ground interactions; changes in immune function, and evaluation of imaging techniques. The experiment mix has included some conducted in flight aboard ISS as well as several which collected data only pre-and postflight. The conduct of these investigations has been facilitated by the Human Research Facility (HRF). HRF Rack I became the first research rack on ISS when it was installed in the US laboratory module Destiny in March 2001. The rack provides a core set of experiment hardware to support investigations, as well as power, data and commanding capability, and stowage. The second HRF rack, to complement the first with additional hardware and stowage capability, will be launched once Shuttle flights resume. Future years will see additional capability to conduct human research on ISS as International Partner modules and facility racks are added to ISS. Crew availability, both as a subject count and time, will remain a major challenge to maximizing the science return from the bioastronautics research program. © 2005 Published by Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Bioastronaut Off, Houston, TX 77058 USA. RP Uri, JJ (reprint author), NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. EM john.j.uri@nasa.gov NR 0 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2005 VL 56 IS 9-12 BP 883 EP 889 DI 10.1016/j.actaastro.2005.01.014 PG 7 WC Engineering, Aerospace SC Engineering GA 925PA UT WOS:000229063800014 PM 15835037 ER PT J AU Schmidt, LL Wood, JA Lugg, DJ AF Schmidt, LL Wood, JA Lugg, DJ TI Gender differences in leader and follower perceptions of social support in Antarctica SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT International Scientific Symposium on Humans in Space CY MAY 18-22, 2003 CL Banff, CANADA SP Canadian Space Agcy ID REALISTIC JOB PREVIEW; TOP MANAGEMENT TEAMS; WORK-GROUP DIVERSITY; PERFORMANCE; HEALTH; ENVIRONMENTS; COHESION; QUALITY AB The purpose of this study was to methodologically explore the links among social support, gender, age, prior experience, leader/follower status, and leadership effectiveness noted in previous accounts from Antarctic stations. Data for this study were collected from volunteers involved in Australian National Antarctic Research Expeditions conducted from 1996 to 2001. Multilevel analysis revealed that most of the variance in perceptions of social support was at the individual level (71%). Perceptions of social support had less variance at the group level (29%) and little variance at the weekly level. At the group level, the explanatory variables we examined included leadership effectiveness, gender similarity, and age similarity. At the individual level, the explanatory variables we examined included age, gender, prior experience, and leader/follower status. An interaction between gender and leader/follower status contributed to a significant model of variation in perceptions of social support. © 2005 Published by Elsevier Ltd. C1 Wyle Labs, Houston, TX USA. Baylor Coll Med, Houston, TX 77030 USA. Australian Antarctic Div, Hobart, Tas, Australia. RP Wood, JA (reprint author), NASA, Lyndon B Johnson Space Ctr, Biobehav Lab SK272, Nasa Rd 1, Houston, TX 77058 USA. EM jwood@ems.jsc.nasa.gov NR 45 TC 1 Z9 1 U1 3 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 2005 VL 56 IS 9-12 BP 923 EP 931 DI 10.1016/j.actaastro.2005.01.019 PG 9 WC Engineering, Aerospace SC Engineering GA 925PA UT WOS:000229063800019 PM 15835048 ER PT J AU Thom, RL Walker, JL AF Thom, RL Walker, JL TI Testing to avert disasters - External Space Shuttle tank foam SO ADVANCED MATERIALS & PROCESSES LA English DT Article C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35801 USA. RP Thom, RL (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35801 USA. EM Robert.l.thom@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD MAY PY 2005 VL 163 IS 5 BP 27 EP 30 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 927DA UT WOS:000229171400002 ER PT J AU Milanovic, IM Zaman, KBMQ AF Milanovic, IM Zaman, KBMQ TI Synthetic jets in crossflow SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 33rd Fluid Dynamics Conference CY JUN 22-26, 2003 CL ORLANDO, FL SP Amer Inst Aeronaut & Astronaut ID VORTEX RING FORMATION; BOUNDARY-LAYER; DUCT AB Results of an experimental investigation on synthetic jets, with and without crossflow, from orifices of different geometry are presented. Jet Reynolds number up to 2.3 x 104 and Stokes number up to 400 are covered. For the round orifice, in the absence of crossflow, the threshold for formation of the synthetic jet is found to be at a stroke length, L-0/D &AP; 0.25. Above L-0/D &AP; 5, the profiles of normalized centerline mean velocity appear to become invariant. It is reasoned that the limiting behavior at high L-0/D is related to the phenomenon of saturation of impulsively generated vortices. For the synthetic jet in crossflow (SJCF), distributions of mean velocity, streamwise vorticity, as well as turbulence intensity are found to be similar to those of a steady jet-in-crossflow (JICF). A pair of counter-rotating streamwise vortices, corresponding to the bound vortex pair of the steady case, is clearly observed. Mean velocity field, for the case of normal injection, exhibits a "dome" of low-momentum fluid pulled up from the boundary layer, and the entire domain is characterized by high turbulence. When the maximum velocity during the discharge stroke of a SJCF equals the exit velocity of a JICF, the penetration of the two are found to be comparable for a given crossflow. Other orifice geometries included a tapered, a pitched, and a cluster of nine, all having the same cross-sectional area at the exit. The flowfield from the cluster, when viewed a few equivalent diameters downstream, resembles that from the single orifice. However, jet penetration is somewhat lower as a result of increased mixing of the distributed jets with the crossflow. Instead of the dome of low-momentum fluid, a pitched SJCF is characterized by a core of high-momentum fluid. Its penetration is the lowest, as expected. The trajectory of the SJCF from a single orifice, normal or pitched, is well represented by the power function correlation available for a JICF. C1 Univ Hartford, Hartford, CT 06117 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Milanovic, IM (reprint author), Univ Hartford, Hartford, CT 06117 USA. OI Milanovic, Ivana/0000-0002-9985-6014 NR 36 TC 28 Z9 28 U1 0 U2 7 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2005 VL 43 IS 5 BP 929 EP 940 DI 10.2514/1.4714 PG 12 WC Engineering, Aerospace SC Engineering GA 923AI UT WOS:000228880600001 ER PT J AU Zhao, HW Balakumar, P AF Zhao, HW Balakumar, P TI Nonlinear disturbance evolution across a hypersonic compression corner SO AIAA JOURNAL LA English DT Article ID DIRECT NUMERICAL-SIMULATION; BOUNDARY-LAYER FLOWS; TRANSITION; SEPARATION AB The nonlinear evolution of the second-mode disturbance across a compression corner under the hypersonic flow condition is studied by spatial direct numerical simulation in this investigation. A fifth-order weighted essentially nonoscillating scheme is employed for this simulation. After the mean flow is obtained, the two- and three-dimensional mono- or random-frequency disturbances are added into the mean How at the beginning of the computational domain. The nonlinear simulations show that two-dimensional disturbance will become saturated downstream of the separation region when its amplitude grows to a quite large value. For three-dimensional monofrequency disturbance evolution, with appropriate initial disturbance amplitude, the nonlinear interactions of the oblique disturbance will first happen at the beginning of the separation region, and some superharmonics will begin to appear in this region, but only downstream of the separation region do these harmonies begin to grow rapidly. Among all of these superharmonics, (0,2) mode shows the greatest growth rate and is responsible for oblique breakdown. With the presence of the two-dimensional primary disturbance, the oblique disturbances show the significant growth rate downstream of the separation region when the two-dimensional primary disturbance reaches the nonlinear saturation. Both mono- and random-frequency disturbance evolution show that the growth of three-dimensional disturbance as a result of secondary instability is responsible for the boundary-layer transition. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. RP Zhao, HW (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. NR 11 TC 2 Z9 2 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2005 VL 43 IS 5 BP 1034 EP 1041 DI 10.2514/1.2244 PG 8 WC Engineering, Aerospace SC Engineering GA 923AI UT WOS:000228880600011 ER PT J AU Uzun, A Hussaini, MY Streett, CL AF Uzun, A Hussaini, MY Streett, CL TI Comparative study of single-block vs multiblock jet flow computations SO AIAA JOURNAL LA English DT Article ID LARGE-EDDY SIMULATION; BOUNDARY-CONDITIONS; SCHEMES C1 Florida State Univ, Sch Computat Sci, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Uzun, A (reprint author), Florida State Univ, Sch Computat Sci, Tallahassee, FL 32306 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2005 VL 43 IS 5 BP 1143 EP 1146 DI 10.2514/1.13429 PG 4 WC Engineering, Aerospace SC Engineering GA 923AI UT WOS:000228880600024 ER PT J AU Summers, RL Martin, DS Meck, JV Coleman, TG AF Summers, RL Martin, DS Meck, JV Coleman, TG TI Mechanism of spaceflight-induced changes in left ventricular mass SO AMERICAN JOURNAL OF CARDIOLOGY LA English DT Article ID POSTSPACEFLIGHT ORTHOSTATIC HYPOTENSION; TIME COURSE; HYPERTROPHY AB Decrements in left ventricular (LV) mass observed after microgravity exposure have been previously postulated to be a central component of spaceflight-induced cardiovascular deconditioning. In this study, echocardiographic measurements of LV mass in astronauts demonstrated a comparative 9.1% reduction in postflight LV mass that returned to preflight values by the third day of recovery. A ground-based study in normal subjects determined that these pre- to postflight LV mass changes could be reproduced by simple dehydration. Reductions in LV mass observed immediately after spaceflight may be secondary to simple physiologic fluid exchanges. (c) 2005 by Excerpta Medica Inc. C1 Univ Mississippi, Med Ctr, Dept Emergency Med, Jackson, MS 39216 USA. NASA, Johnson Space Ctr, Wyle Labs, Houston, TX 77058 USA. NASA, Johnson Space Ctr, Human Adaptat & Countermeasures Off, Space & Life Sci Directorate, Houston, TX 77058 USA. Univ Mississippi, Med Ctr, Dept Physiol & Biophys, Jackson, MS 39216 USA. RP Summers, RL (reprint author), Univ Mississippi, Med Ctr, Dept Emergency Med, 2500 N State St, Jackson, MS 39216 USA. EM rsummers@pol.net NR 9 TC 21 Z9 21 U1 2 U2 4 PU EXCERPTA MEDICA INC-ELSEVIER SCIENCE INC PI BRIDGEWATER PA 685 ROUTE 202-206 STE 3, BRIDGEWATER, NJ 08807 USA SN 0002-9149 J9 AM J CARDIOL JI Am. J. Cardiol. PD MAY 1 PY 2005 VL 95 IS 9 BP 1128 EP 1130 DI 10.1016/j.amjcard.2005.01.033 PG 3 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 921BF UT WOS:000228738500027 PM 15842991 ER PT J AU Anderson, MS AF Anderson, MS TI Microfluidics and chromatography with an atomic force microscope SO ANALYTICAL CHEMISTRY LA English DT Article ID SHEAR-DRIVEN CHROMATOGRAPHY; ENHANCED RAMAN-SCATTERING; SINGLE MOLECULES; SEPARATIONS; DEVICES; FLOWS; TIPS AB A combined atomic force microscope (AFM) and Raman spectrometer is presented as a microfluidic device for pumping, sampling, and trace chemical analysis. The AFM tip-cantilever provides a mechanism for sheardriven pumping of fluids in microchannels. Shear-driven pumping allows rapid flow rates and avoids the limitations of conventional pumping. The AFM's ability to translate sub-femtoliter volumes of fluid also proves a mechanism for fluidic switching and sample injection. In addition, the AFM is used to image liquid surfaces in microchannels and remove samples for very sensitive spectral analysis. Surface-enhanced Raman spectroscopy localized near the AFM tip provides chemical information of the sampled fluids. The results demonstrate the feasibility of integrating the AFM with microfluidic circuits and shear-driven chromatography and the potential for nanometer-scale chromatography. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Anderson, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 125-109, Pasadena, CA 91109 USA. EM mark.s.andersn@jpl.nasa.gov NR 27 TC 9 Z9 9 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2005 VL 77 IS 9 BP 2907 EP 2911 DI 10.1021/ac048294k PG 5 WC Chemistry, Analytical SC Chemistry GA 922ZD UT WOS:000228877500042 PM 15859610 ER PT J AU Kloepfer, JA Mielke, RE Nadeau, JL AF Kloepfer, JA Mielke, RE Nadeau, JL TI Uptake of CdSe and CdSe/ZnS quantum dots into bacteria via purine-dependent mechanisms SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID GLUTAMINE PHOSPHORIBOSYLPYROPHOSPHATE AMIDOTRANSFERASE; BACILLUS-SUBTILIS; ESCHERICHIA-COLI; PROTEIN; CELLS; NANOPARTICLES; FLUORESCENCE; RECOGNITION; METABOLISM; AGENTS AB Quantum dots (QDs) rendered water soluble for biological applications are usually passivated by several inorganic and/or organic layers in order to increase fluorescence yield. However, these coatings greatly increase the size of the particle, making uptake by microorganisms impossible. We find that adenine- and AMP-conjugated QDs are able to label bacteria only if the particles are < 5 nm in diameter. Labeling is dependent upon purine-processing mechanisms, as mutants lacking single enzymes demonstrate a qualitatively different signal than do wild-type strains. This is shown for two example species, one gram negative and one gram positive. Wild-type Bacillus subtilis incubated with QDs conjugated to adenine are strongly fluorescent; very weak signal is seen in mutant cells lacking either adenine deaminase or adenosine phosphoribosyltransferase. Conversely, QD-AMP conjugates label mutant strains more efficiently than the wild type. In Escherichia coli, QD conjugates are taken up most strongly by adenine auxotrophs and are extruded from the cells over a time course of hours. No fluorescent labeling is seen in killed bacteria or in the presence of EDTA or an excess of unlabeled adenine, AMP, or hypoxanthine. Spectroscopy and electron microscopy suggest that QDs of < 5 nm can enter the cells whole, probably by means of oxidative damage to the cell membrane which is aided by light. C1 CALTECH, Jet Prop Lab, Ctr Life Detect, Pasadena, CA 91109 USA. RP Nadeau, JL (reprint author), McGill Univ, Dept Biomed Engn, 3775 Univ St, Montreal, PQ H3A 2B4, Canada. EM jay.nadeau@mcgill.ca NR 34 TC 140 Z9 146 U1 3 U2 54 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD MAY PY 2005 VL 71 IS 5 BP 2548 EP 2557 DI 10.1128/AEM.71.5.2548-2557.2005 PG 10 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 926EH UT WOS:000229105300045 PM 15870345 ER PT J AU Johansson, S Gull, TR Hartman, H Letokhov, VS AF Johansson, S Gull, TR Hartman, H Letokhov, VS TI Metastable hydrogen absorption in ejecta close to eta Carinae SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic processes; line : formation; line : profiles; HII regions; radiation mechanisms : non-thermal; stars : individual : eta Carinae ID HOMUNCULUS-NEBULA; VELOCITIES; DISCOVERY; WIND AB Spectroscopy with the high spatial resolution of the Hubble Space Telescope (HST) reveals narrow absorption in the hydrogen Balmer lines in spectra of Eta Carinae and the nearby nebular-scattered starlight. While hydrogen Balmer absorption lines are seen in stellar photospheres and winds, we are not aware of such being seen in galactic nebulae. This exceptional case is caused by intense stellar UV radiation acting on high-density neutral clumps of gas in the close vicinity of the central source. The interaction of the UV radiation with hydrogen results in photo-ionization and photo-excitation leading to a non-equilibrium population of the metastable 2s S-2 level. This occurs throughout the equatorial region surrounding eta Carinae in sufficient quantity to produce strong narrow absorption on top of the broad P Cygni emission profile. This absorption can be considered to be a probe of the very non-uniform ejecta in the disk region surrounding eta Carinae. C1 Lund Univ, Lund Observ, S-22100 Lund, Sweden. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Russian Acad Sci, Inst Spect, Troitsk 142190, Moscow Region, Russia. RP Johansson, S (reprint author), Lund Univ, Lund Observ, POB 43, S-22100 Lund, Sweden. EM sveneric.johansson@astro.lu.se; theodore.r.gull@nasa.gov; henrik.hartman@astro.lu.se; vladilen.letokhov@astro.lu.se RI Gull, Theodore/D-2753-2012; Hartman, Henrik/K-3113-2013 OI Gull, Theodore/0000-0002-6851-5380; NR 19 TC 10 Z9 10 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 435 IS 1 BP 183 EP 189 DI 10.1051/0004-6361:20041193 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 920LM UT WOS:000228690500023 ER PT J AU Stahl, O Weis, K Bomans, DJ Davidson, K Gull, TR Humphreys, RM AF Stahl, O Weis, K Bomans, DJ Davidson, K Gull, TR Humphreys, RM TI A spectroscopic event of eta Car viewed from different directions: The data and first results SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : eta Car; stars : circumstellar matter; stars : mass-loss; stars : evolution ID HUBBLE-SPACE-TELESCOPE; HOMUNCULUS NEBULA; BINARY HYPOTHESIS; STELLAR WIND; CARINAE; EJECTA; STAR; SPECTROGRAPH; EMISSION; CYCLE AB We present spectroscopic observations with high spectral resolution of. Car as seen by the SE lobe of the Homunculus nebula over the 2003.5 "spectroscopic event". The observed spectra represent the stellar spectrum emitted near the pole of the star and are much less contaminated with nebular emission lines than direct observations of the central object. The "event" is qualitatively similar near the pole to what is observed in direct spectra of the star ( more equator-on at 45 degrees), but shows interesting differences. The observations show that the equivalent width changes of Ha emission and other lines are less pronounced at the pole than in the line of sight. Also the absorption components appear less variable. A pronounced high-velocity absorption is present near the event in the He. lines indicating a mass-ejection event. This feature is also seen, but less pronounced, in the hydrogen lines. He II lambda 4686 emission is observed for a brief period of time near the event and appears, if corrected for light travel time, to precede similar emission in the direct view. Our observations indicate that the event is probably not only a change in ionization and excitation structure or a simple eclipse-like event. C1 Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. Ruhr Univ Bochum, Astron Inst, D-44780 Bochum, Germany. NASA, Goddard Space Flight Ctr, Lab Astron & Space Sci, Greenbelt, MD 20771 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. RP Stahl, O (reprint author), Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. EM O.Stahl@lsw.uni-heidelberg.de RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 45 TC 33 Z9 33 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 435 IS 1 BP 303 EP 312 DI 10.1051/0004-6361:20042547 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 920LM UT WOS:000228690500035 ER PT J AU Emery, JP Burr, DM Cruikshank, DP Brown, RH Dalton, JB AF Emery, JP Burr, DM Cruikshank, DP Brown, RH Dalton, JB TI Near-infrared (0.8-4.0 mu m) spectroscopy of Mimas, Enceladus, Tethys, and Rhea SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE planets and satellites : individual : Enceladus; planets and satellites : individual : Mimas; infrared : solar system; planets and satellites : individual : Rhea; planets and satellites : individual : Tethys; planets and satellites : general ID OUTER SOLAR-SYSTEM; SATURNS MAGNETOSPHERE; SURFACE-COMPOSITION; GEOLOGICAL HISTORIES; PLASMA OBSERVATIONS; VOYAGER PHOTOMETRY; PLANETARY SURFACES; INNER SATELLITES; ICE ANALOGS; WATER ICE AB Spectral measurements from the ground in the time leading up to the Cassini mission at Saturn provide important context for the interpretation of the forthcoming spacecraft data. Whereas ground-based observations cannot begin to approach the spatial scales Cassini will achieve, they do possess the benefits of better spectral resolution, a broader possible time baseline, and unique veiewing geometries not obtained by spacecraft (i.e., opposition). In this spirit, we present recent NIR reflectance spectra of four icy satellites of Saturn measured with the SpeX instrument at the IRTF. These measurements cover the range 0.8 - 4.0 mu m of both the leading and trailing sides of Tethys and the leading side of Rhea. The L-band region ( 2.8 - 4.0 mu m) offers new opportunities for searches of minor components on these objects. Additionally, these data include 0.8 - 2.5 mu m spectra of both the leading and trailing sides of Mimas and of the ( mostly) trailing side of Enceladus. The spectrum of Enceladus shows activity near 2.25 mu m that we interpret as a possible signature of NH3 ice. The presence of ammonia in the Saturn system is not unexpected, and may help explain the apparent recent geologic activity of Enceladus. Analysis of leading/trailing differences in H2O band depths, spectral slopes, and albedo imply a separate regime of surface modification for Mimas and Enceladus than for the more distant icy satellites ( Tethys, Dione, Rhea). Aside from the potential NH3 on Enceladus, no other minor constituents are detected in these icy surfaces. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. US Geol Survey, Astrogeol Branch, Flagstaff, AZ 86001 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Emery, JP (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 245-6, Moffett Field, CA 94035 USA. EM jemery@mail.arc.nasa.gov NR 57 TC 67 Z9 67 U1 2 U2 4 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 435 IS 1 BP 353 EP 362 DI 10.1051/0004-6361:20042482 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 920LM UT WOS:000228690500040 ER PT J AU Urosevic, D Pannuti, TG Duric, N Theodorou, A AF Urosevic, D Pannuti, TG Duric, N Theodorou, A TI The Sigma-D relation for supernova remnants in nearby galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : supernova remnants; methods : statistical; radio continuum : galaxies ID LARGE MAGELLANIC CLOUD; COMPACT RADIO-SOURCES; HUBBLE-SPACE-TELESCOPE; NOVA REMNANTS; X-RAY; SURFACE BRIGHTNESS; OBSERVATIONAL DATA; SPIRAL GALAXIES; SHOCK FRONTS; COSMIC-RAYS AB This paper examines relations between the radio surface brightness S and the diameter D ( also known as S D relations) for a sample of extragalactic supernova remnants (SNRs) as constructed from a combination of published data and data from our own surveys. Our sample of extragalactic SNRs is the largest ever devised for the purpose of analyzing Sigma - D relations. The main results of this paper may be summarized as follows: (i) the empirical relations for SNRs in 10 of the 11 nearby galaxies studied have the approximately trivial Sigma proportional to D-2 form, therefore limiting their interpretation as physically meaningful relations. In addition, these relations are subject to selection effects rendering them even less useful. Further Monte Carlo simulations suggest that the effect of survey sensitivity has the opposite effect of volume selection ( e. g. Malmquist bias, a volume selection effect that shapes the Galactic sample) by tending to flatten the slopes toward a trivial relation. In this case, the true slopes may be steeper than the observed slopes; (ii) compact M 82 SNRs appear to follow a uniquely different Sigma-D relation in comparison to the larger, older SNRs in the other 10 galaxies. Monte Carlo simulations suggest that the probability of this difference arising by chance is approximate to 1% to 10%, depending on what is assumed regarding the underlying SNR population; (iii) three candidate hypernova remnants were identified in our sample of 11 nearby galaxies. C1 Univ Belgrade, Fac Math, Dept Astron, YU-11000 Belgrade, Serbia Monteneg, Yugoslavia. Isaac Newton Inst Chile, Yugoslavia Branch, Belgrade, Yugoslavia. CALTECH, Jet Prop Lab, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ New Mexico, Dept Phys & Astron, Inst Astrophys, Albuquerque, NM 87131 USA. Wayne State Univ, Dept Radiat Oncol, Karmanos Canc Inst, Detroit, MI 48201 USA. RP Urosevic, D (reprint author), Univ Belgrade, Fac Math, Dept Astron, Studentski Trg 16,PO 550, YU-11000 Belgrade, Serbia Monteneg, Yugoslavia. EM dejanu@matf.bg.ac.yu NR 91 TC 24 Z9 24 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 435 IS 2 BP 437 EP U20 DI 10.1051/0004-6361:20042535 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AC UT WOS:000228806600008 ER PT J AU Steenbrugge, KC Kaastra, JS Crenshaw, DM Kraemer, SB Arav, N George, IM Liedahl, DA van der Meer, RLJ Paerels, FBS Turner, TJ Yaqoob, T AF Steenbrugge, KC Kaastra, JS Crenshaw, DM Kraemer, SB Arav, N George, IM Liedahl, DA van der Meer, RLJ Paerels, FBS Turner, TJ Yaqoob, T TI Simultaneous X-ray and UV spectroscopy of the Seyfert galaxy NGC 5548 - II. Physical conditions in the X-ray absorber SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : Seyfert; quasars : individual : NGC 5548; galaxies : active; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; XMM-NEWTON; NGC 5548; BLACK-HOLE; ULTRAVIOLET ABSORBER; COLUMN DENSITY; IONIZED-GAS; NGC-3783; VARIABILITY; CHANDRA AB We present the results from a 500 ks Chandra observation of the Seyfert 1 galaxy NGC 5548. We detect broadened ( full width half maximum = 8000 km s(-1)) emission lines of O VII. and C.. in the spectra, similar to those observed in the optical and UV bands. The source was continuously variable, with a 30% increase in luminosity in the second half of the observation. The gradual increase in luminosity occurred over a timescale of similar to 300 ks. No variability in the warm absorber was detected between the spectra from the first 170 ks and the second part of the observation. The longer wavelength range of the LETGS resulted in the detection of absorption lines from a broad range of ions, in particular of C, N, O, Ne, Mg, Si, S and Fe. The velocity structure of the X- ray absorber is consistent with the velocity structure measured simultaneously in the ultraviolet spectra. We find that the highest velocity outflow component, at - 1040 km s(-1), becomes increasingly important for higher ionization parameters. This velocity component spans at least three orders of magnitude in ionization parameter, producing both highly ionized X- ray absorption lines ( Mg XII, Si XIV) as well as UV absorption lines. A similar conclusion is very probable for the other four velocity components. Based upon our observations, we argue that the warm absorber probably does not manifest itself in the form of photoionized clumps in pressure equilibrium with a surrounding wind. Instead, a model with a continuous distribution of column density versus ionization parameter gives an excellent fit to our data. From the shape of this distribution and the assumption that the mass loss through the wind should be smaller than the accretion rate onto the black hole, we derive upper limits to the solid angle as small as 10(-4) sr. From this we argue that the outflow occurs in density- stratified streamers. The density stratification across the stream then produces the wide range of ionization parameter observed in this source. We determine an upper limit of 0.3 M. yr(-1) for the mass loss from the galaxy due to the observed outflows. C1 SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. Georgia State Univ, Dept Phys & Astron, Astron Off, Atlanta, GA 30303 USA. Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Colorado, CASA, Boulder, CO 80309 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Steenbrugge, KC (reprint author), SRON, Natl Inst Space Res, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. EM K.C.Steenbrugge@sron.nl NR 43 TC 98 Z9 99 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 434 IS 2 BP 569 EP U6 DI 10.1051/0004-6361:20047138 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 915SO UT WOS:000228326900017 ER PT J AU Matsuura, M Zijlstra, AA van Loon, JT Yamamura, I Markwick, AJ Whitelock, PA Woods, PM Marshall, JR Feast, MW Waters, LBFM AF Matsuura, M Zijlstra, AA van Loon, JT Yamamura, I Markwick, AJ Whitelock, PA Woods, PM Marshall, JR Feast, MW Waters, LBFM TI Three-micron spectra of AGB stars and supergiants in nearby galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : AGB and post-AGB; infrared : stars; galaxies : stellar content; stars : atmospheres ID LARGE-MAGELLANIC-CLOUD; ASYMPTOTIC GIANT BRANCH; MASS-LOSS RATES; ROTATION-VIBRATION BANDS; SAGITTARIUS DWARF GALAXY; LONG-PERIOD VARIABLES; CARBON STARS; ISO-SWS; INFRARED PHOTOMETRY; PLANETARY-NEBULAE AB The dependence of stellar molecular bands on the metallicity is studied using infrared L- band spectra of AGB stars ( both carbon- rich and oxygen- rich) and M- type supergiants in the Large and Small Magellanic Clouds ( LMC and SMC) and in the Sagittarius Dwarf Spheroidal Galaxy. The spectra cover SiO bands for oxygen- rich stars, and acetylene ( C2H2), CH and HCN bands for carbon- rich AGB stars. The equivalent width of acetylene is found to be high even at low metallicity. The high C2H2 abundance can be explained with a high carbon- to- oxygen ( C/ O) ratio for lower metallicity carbon stars. In contrast, the HCN equivalent width is low: fewer than half of the extra- galactic carbon stars show the 3.5 mu m HCN band, and only a few LMC stars show high HCN equivalent width. HCN abundances are limited by both nitrogen and carbon elemental abundances. The amount of synthesized nitrogen depends on the initial mass, and stars with high luminosity ( i. e. high initial mass) could have a high HCN abundance. CH bands are found in both the extra- galactic and Galactic carbon stars. One SMC post- AGB star, SMC- S2, shows the 3.3 mu m PAH band. This first detection of a PAH band from an SMC post- AGB star confirms PAHs can form in these low- metallicity stars. None of the oxygen- rich LMC stars show SiO bands, except one possible detection in a low quality spectrum. The limits on the equivalent widths of the SiO bands are below the expectation of up to 30 angstrom for LMC metallicity. Several possible explanations are discussed, mostly based on the effect of pulsation and circumstellar dust. The observations imply that LMC and SMC carbon stars could reach mass- loss rates as high as their Galactic counterparts, because there are more carbon atoms available and more carbonaceous dust can be formed. On the other hand, the lack of SiO suggests less dust and lower mass- loss rates in low- metallicity oxygen- rich stars. The effect on the ISM dust enrichment is discussed. C1 Univ Manchester, Sch Phys & Astron, Manchester M60 1QD, Lancs, England. Univ Keele, Sch Chem & Phys, Astrophys Grp, Keele ST5 5BG, Staffs, England. Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. S African Astron Observ, ZA-7935 Cape Town, South Africa. Univ Cape Town, Dept Astron, ZA-7701 Rondebosch, South Africa. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Heverlee, Belgium. RP Matsuura, M (reprint author), Univ Manchester, Sch Phys & Astron, POB 88, Manchester M60 1QD, Lancs, England. EM m.matsuura@manchester.ac.uk RI Woods, Paul/E-6926-2011 OI Woods, Paul/0000-0003-4340-3590 NR 80 TC 56 Z9 56 U1 0 U2 3 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 434 IS 2 BP 691 EP 706 DI 10.1051/0004-6361:20042305 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 915SO UT WOS:000228326900030 ER PT J AU Galliano, E Madden, SC Jones, AP Wilson, CD Bernard, JP AF Galliano, E Madden, SC Jones, AP Wilson, CD Bernard, JP TI ISM properties in low-metallicity environments III. The dust spectral energy distributions of II Zw40, He 2-10 and NGC1140 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : dust; extinction; galaxies : dwarf; galaxies : starburst; infrared : galaxies; submillimeter ID SMALL-MAGELLANIC-CLOUD; WOLF-RAYET GALAXIES; COMPACT DWARF GALAXIES; SUPER-STAR-CLUSTERS; STARBURST GALAXY; INTERSTELLAR DUST; INFRARED-EMISSION; IRREGULAR GALAXIES; MILKY-WAY; LUMINOSITY FUNCTION AB We present new 450 and 850 mu m SCUBA data and 1.3 mm MAMBO data of the dwarf galaxies IIZw 40, He 2-10 and NGC 1140. Additional ISOCAM, IRAS as well as ground based data are used to construct the observed mid-infrared to millimeter spectral energy distribution of these galaxies. These spectral energy distributions are modeled in a self-consistent way, as was achieved with NGC 1569 (Galliano et al. 2003, A&A, 407, 159), synthesizing both the global stellar radiation field and the dust emission, with further constraints provided by the photoionisation of the gas. Our study shows that low-metallicity galaxies have very different dust properties compared to the Galaxy. Our main results are: (i) a paucity of PAHs which are likely destroyed by the hard penetrating radiation field; (ii) a very small (similar to 3-4 nm) average size of grains, consistent with the fragmentation and erosion of dust particles by the numerous shocks; (iii) a significant millimetre excess in the dust spectral energy distribution which can be explained by the presence of ubiquitous very cold dust (T = 5-9 K) accounting for 40 to 80% of the total dust mass, probably distributed in small clumps. We derive a range of gas-to-dust mass ratios between 300 and 2000, larger than the Galactic values and dust-to-metals ratios of 1/30 to 1/2. The modeled dust size distributions are used to synthesize an extinction curve for each galaxy. The UV slopes of the extinction curves resemble that observed in some regions in the Large Magellanic Cloud. The 2175 angstrom bumps of the modeled extinction curves are weaker than that of the Galaxy, except in the case of IIZw 40 where we are unable to accurately constrain the 2175 angstrom bump carrier. C1 CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Paris 11, IAS, F-91405 Orsay, France. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. CESR, F-31028 Toulouse, France. RP Galliano, E (reprint author), NASA, Goddard Space Flight Ctr, Observat Cosmol Lab, Greenbelt, MD 20771 USA. EM galliano@avak.gsfc.nasa.gov NR 90 TC 134 Z9 134 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 2005 VL 434 IS 3 BP 867 EP 885 DI 10.1051/0004-6361:20042369 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 926HR UT WOS:000229114800009 ER PT J AU Turner, NJ Blaes, OM Socrates, A Begelman, MC Davis, SW AF Turner, NJ Blaes, OM Socrates, A Begelman, MC Davis, SW TI The effects of photon bubble instability in radiation-dominated accretion disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; instabilities; MHD; radiative transfer ID 2 SPACE DIMENSIONS; FLUX-LIMITED DIFFUSION; MAGNETOHYDRODYNAMICS CODE; ASTROPHYSICAL FLOWS; BLACK-HOLES; HYDRODYNAMIC ALGORITHMS; BINARY-SYSTEMS; ZEUS-2D; TESTS; SIMULATIONS AB We examine the effects of photon bubble instability in radiation-dominated accretion disks such as those found around black holes in active galactic nuclei and X-ray binary star systems. Two- and three-dimensional numerical radiation MHD calculations of small patches of disk are used. Modes with wavelengths shorter than the gas pressure scale height grow faster than the orbital frequency in the disk surface layers. The fastest growth rate observed is 5 times the orbital frequency and occurs on nearly vertical magnetic fields. The spectrum of linear modes is in good agreement with a WKB analysis that indicates still faster growth at unresolved scales, with a maximum growth rate proportional to the gravitational acceleration and inversely proportional to the gas sound speed. Disturbances reaching nonlinear amplitudes steepen into trains of shocks similar to a one-dimensional periodic nonlinear analytic solution. Variations in propagation speed result in merging of adjacent fronts, and over time the shock spacing and amplitude increase. Growth is limited by the strength of the magnetic field. The shock train structure is disrupted when the ram pressure of the disturbances exceeds the magnetic pressure. The maximum horizontal density variations are comparable to the ratio of magnetic to gas pressure and in our calculations exceed 100. Under the conditions considered, radiation diffuses through the inhomogeneneous flow 5 times faster than through the initial hydrostatic equilibrium, and the net cooling rate is several times greater than in a similar calculation without magnetic fields that shows the effects of convection. These results indicate that photon bubbles may be important in cooling radiation-dominated accretion disks. The Shaviv type I global instability grows faster than the orbital frequency in calculations of the disk surface layers with lower boundaries of fixed temperature, but is weak or absent in calculations spanning the disk thickness. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Turner, NJ (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. EM neal.turner@jpl.nasa.gov NR 33 TC 41 Z9 41 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP 267 EP 288 DI 10.1086/428723 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OI UT WOS:000228554200028 ER PT J AU Tuthill, PG Monnier, JD Danchi, WC AF Tuthill, PG Monnier, JD Danchi, WC TI Multiwavelength diffraction-limited imaging of the evolved carbon star IRC+10216. II. SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : individual (IRC+10216); stars : mass loss; techniques : high angular resolution; techniques : interferometric ID CIRCUMSTELLAR ENVELOPE; DUST SHELL; INTERFEROMETRY; IRC; TELESCOPE; EVOLUTION AB High angular resolution images of IRC + 10216 taken at various bandpasses within the near-infrared H, K, and L bands are presented. The maps have the highest angular resolution yet recovered and were reconstructed from interferometric measurements obtained at the Keck I telescope in 1997 December and 1998 April, forming a subset of a seven-epoch monitoring program presented earlier by Tuthill and coworkers in Paper I. Systematic changes with observing wavelength are found and discussed in the context of present geometrical models for the circumstellar envelope. With these new high-resolution, multiwavelength data and contemporaneous photometry, we also revisit the hypothesis that the bright compact core of the nebula ( component "A'') marks the location of the central carbon star. We find that directly measured properties of the core ( angular size, flux density, color temperature) are consistent with a reddened carbon star photosphere (line-of-sight tau(2.2) = 5.3). C1 Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tuthill, PG (reprint author), Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. NR 22 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP 352 EP 358 DI 10.1086/428932 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OI UT WOS:000228554200034 ER PT J AU Nerney, S Suess, ST AF Nerney, S Suess, ST TI Stagnation flow in thin streamer boundaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : corona ID SLOW SOLAR-WIND; CORONAL STREAMERS; MAGNETOHYDRODYNAMIC MODELS; MINIMUM; 2-FLUID; REGION; BELT AB Slow solar wind is believed to arise in the legs or near the cusp of streamers, inside the brightness boundary. In an earlier study, we used an analytic model of flow in this layer to analyze the effect of the magnetic field on the geometry of the flow. That study successfully described those conditions that can lead to a decrease of the flow speed with increasing height near the cusp of the closed magnetic helmet inside a streamer. The model was, however, restricted to a radial brightness boundary on the streamer and hence to a relatively thick outflow region near the cusp. Here this restriction is relaxed through the explicit introduction of a coronal hole - like region outside the brightness boundary. We use the model to describe flow solutions for outflow in a thin layer inside the brightness boundary. The flow geometry now can be constrictive just above the cusp, and we show solutions of this type. Many solutions then show a diverging geometry at greater heights above the cusp, out to at least 5 R(.). We fail to find solutions in which the geometry alone leads to slow flow but give a more general description than before of conditions favoring slow flow and, consequently, gravitational settling in the legs of streamers. C1 Ohio Univ, Lancaster, OH 43130 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. RP Nerney, S (reprint author), Ohio Univ, Lancaster, OH 43130 USA. EM nerney@oak.cats.ohiou.edu; steven.t.suess@nasa.gov NR 31 TC 10 Z9 10 U1 1 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP 378 EP 391 DI 10.1086/428924 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OI UT WOS:000228554200037 ER PT J AU Landi, S Velli, M AF Landi, S Velli, M TI Alfven waves and shock wave formation at an X-point magnetic field configuration SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; methods : numerical; MHD; shock waves; Sun : corona ID TRANSVERSELY INHOMOGENEOUS-MEDIUM; CORONAL LOOP OSCILLATIONS; SPEED SOLAR-WIND; PARTICLE-ACCELERATION; BOUNDARY-CONDITIONS; SIMULATIONS; PROPAGATION; MAGNETOHYDRODYNAMICS; DISSIPATION; EVOLUTION AB We present MHD numerical simulations of the propagation of Alfven waves in inhomogeneous magnetic fields whose topology consists of two-dimensional X-points threaded by a nonvanishing normal component. The coupling of the waves with the background field gradients leads to the development of fast-mode shock trains propagating normal to the average normal magnetic field. The fronts occur with a frequency matching that of the generating Alfven wave. Energy in the original Alfven wave packet is channeled via mode transformation to the fast waves and into the shocks, where it is dissipated at a rate independent of the Reynolds number. Such X-point shock trains might therefore play an important role in the heating of the solar corona plasma and, more generally, in cosmic particle acceleration. C1 Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Pisa, Dipartimento Fis Enrico Fermi, I-56127 Pisa, Italy. RP Landi, S (reprint author), Univ Florence, Dipartimento Astron & Sci Spazio, Largo Enrico Fermi 2, I-50125 Florence, Italy. EM slandi@arcetri.astro.it; velli@arcetri.astro.it RI Landi, Simone/G-7282-2015 OI Landi, Simone/0000-0002-1322-8712 NR 37 TC 24 Z9 24 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP 392 EP 401 DI 10.1086/428822 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OI UT WOS:000228554200038 ER PT J AU Keenan, FP Aggarwal, KM Ryans, RSI Milligan, RO Bloomfield, DS Brosius, JW Davila, JM Thomas, RJ AF Keenan, FP Aggarwal, KM Ryans, RSI Milligan, RO Bloomfield, DS Brosius, JW Davila, JM Thomas, RJ TI Fe XI emission lines in a high-resolution extreme-ultraviolet active region spectrum obtained by the Solar Extreme Ultraviolet Research Telescope and Spectrograph SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; ultraviolet : general ID EFFECTIVE COLLISION STRENGTHS; ELECTRON-IMPACT EXCITATION; FINE-STRUCTURE LEVELS; ATOMIC DATABASE; ANGSTROMS; IDENTIFICATIONS; WAVELENGTHS; INTENSITIES; SUN; CHIANTI AB New calculations of radiative rates and electron impact excitation cross sections for Fe xi are used to derive emission-line intensity ratios involving 3s(2)3p(4) - 3s(2)3p(3)3d transitions in the 180 - 223 angstrom wavelength range. These ratios are subsequently compared with observations of a solar active region obtained during the 1995 flight of the Solar Extreme Ultraviolet Research Telescope and Spectrograph (SERTS). The version of SERTS flown in 1995 incorporated a multilayer grating that enhanced the instrumental sensitivity for features in the similar to 170 - 225 angstrom wave-length range, observed in second order between 340 and 450 angstrom. This enhancement led to the detection of many emission lines not seen on previous SERTS flights, which were measured with the highest spectral resolution (0.03 angstrom) ever achieved for spatially resolved active region spectra in this wavelength range. However, even at this high spectral resolution, several of the Fe xi lines are found to be blended, although the sources of the blends are identified in the majority of cases. The most useful Fe xi electron density diagnostic line intensity ratio is I(184.80 angstrom)/ I(188.21 angstrom). This ratio involves lines close in wavelength and free from blends, and it varies by a factor of 11.7 between N(e) = 10(9) and 10(11) cm(-3) yet shows little temperature sensitivity. An unknown line in the SERTS spectrum at 189.00 angstrom is found to be due to Fe xi, the first time ( to our knowledge) this feature has been identified in the solar spectrum. Similarly, there are new identifications of the Fe XI 192.88, 198.56, and 202.42 angstrom features, although the latter two are blended with S VIII/ Fe XII and Fe XIII, respectively. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Keenan, FP (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Univ Rd, Belfast BT7 1NN, Antrim, North Ireland. EM f.keenan@qub.ac.uk RI Bloomfield, Shaun/G-5809-2011 OI Bloomfield, Shaun/0000-0002-4183-9895 NR 28 TC 9 Z9 9 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP 428 EP 435 DI 10.1086/429142 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OI UT WOS:000228554200042 ER PT J AU Cruikshank, DP Stansberry, JA Emery, JP Fernandez, YR Werner, MW Trilling, DE Rieke, GH AF Cruikshank, DP Stansberry, JA Emery, JP Fernandez, YR Werner, MW Trilling, DE Rieke, GH TI The high-albedo Kuiper Belt object (55565) 2002 AW(197) SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : solar system; Kuiper Belt; minor planets, asteroids ID NEAR-EARTH ASTEROIDS; THERMAL-MODEL; SOURCE COUNTS; SURFACE; SIZE; STANDARDS AB We detected thermal emission from the Kuiper Belt object 2002 AW(197) in 2003 December and again in 2004 April using the Multiband Imaging Photometer on the Spitzer Space Telescope. In combination with the absolute visual magnitude, the thermal measurements indicate a geometric albedo of 0.17 +/- 0.03 and a diameter of km. The albedo of 2002 AW(197) is significantly higher than the 0.04 value typically assumed for trans-Neptunian objects, and consequently the object is smaller than previously thought based on that assumption. Our thermal measurements at two wavelengths ( 24 and 70 mm) allow us to constrain the surface temperature and thereby place constraints on the thermal inertia. We find that the standard thermal model (STM) is inconsistent with the 24/70 mu m color unless we set the beaming parameter eta > 0.95, indicating that the object has a significant thermal inertia and, therefore, that the STM is inappropriate. The other end-member thermal inertia model is the fast-rotator, or isothermal-latitude, model (ILM). The data are well represented by an ILM with the pole of rotation inclined to the Sun by 45 degrees +/- 10 degrees. The high albedo is consistent with a surface containing significant amounts of weakly absorbing materials, with ices and/or fine-grained silicates as likely candidates. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. SETI Inst, Mountain View, CA 94043 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. EM dale.p.cruikshank@nasa.gov OI Fernandez, Yanga/0000-0003-1156-9721 NR 27 TC 16 Z9 16 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2005 VL 624 IS 1 BP L53 EP L56 DI 10.1086/430420 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 918OJ UT WOS:000228554300014 ER PT J AU Garcia, J Mendoza, C Bautista, MA Gorczyca, TW Kallman, TR Palmeri, P AF Garcia, J Mendoza, C Bautista, MA Gorczyca, TW Kallman, TR Palmeri, P TI K-shell photoabsorption of oxygen ions SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; atomic processes; line : formation; X-rays : general ID PHOTOIONIZATION CROSS-SECTIONS; R-MATRIX APPROACH; X-RAY-EMISSION; ATOMIC OXYGEN; XMM-NEWTON; VACANCY STATES; OPACITY CALCULATIONS; RESONANCE LINES; ABSORPTION-EDGE; AUGER SPECTRUM AB Extensive calculations of the atomic data required for the spectral modeling of the K-shell photoabsorption of oxygen ions have been carried out in a multicode approach. The present level energies and wavelengths for the highly ionized species (electron occupancies 2 <= N <= 4) are accurate to within 0.5 eVand 0.02 angstrom, respectively. For N > 4, lack of measurements, wide experimental scatter, and discrepancies among theoretical values are handicaps in reliable accuracy assessments. The radiative and Auger rates are expected to be accurate to 10% and 20%, respectively, except for transitions involving strongly mixed levels. Radiative and Auger dampings have been taken into account in the calculation of photoabsorption cross sections in the K-threshold region, leading to overlapping Lorentzian shaped resonances of constant widths that cause edge smearing. The behavior of the improved opacities in this region has been studied with the XSTAR modeling code using simple constant density slab models and is displayed for a range of ionization parameters. C1 Inst Venezolano Invest Cient, Ctr Fis, Caracas 1020A, Venezuela. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Mons Hainaut, B-7000 Mons, Belgium. RP Inst Venezolano Invest Cient, Ctr Fis, Apartado 21827, Caracas 1020A, Venezuela. EM jgarcia@ivic.ve; claudio@ivic.ve; mbautist@ivic.ve; thomas.gorczyca@wmich.edu; timothy.r.kallman@nasa.gov; patrick.palmeri@umh.ac.be NR 53 TC 53 Z9 53 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 68 EP 79 DI 10.1086/428712 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000003 ER PT J AU O'Dwyer, IJ Bersanelli, M Childers, J Figueiredo, N Halevi, D Huey, G Lubin, PM Maino, D Mandolesi, N Marvil, J Meinhold, PR Mejia, J Natoli, P O'Neill, H Pina, A Seiffert, MD Stebor, NC Tello, C Villela, T Wandelt, BD Williams, B Wuensche, CA AF O'Dwyer, IJ Bersanelli, M Childers, J Figueiredo, N Halevi, D Huey, G Lubin, PM Maino, D Mandolesi, N Marvil, J Meinhold, PR Mejia, J Natoli, P O'Neill, H Pina, A Seiffert, MD Stebor, NC Tello, C Villela, T Wandelt, BD Williams, B Wuensche, CA TI The cosmic microwave background anisotropy power spectrum from the BEAST experiment SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmic microwave background; cosmology : observations; large-scale structure of universe ID SCANNING-TELESCOPE BEAST; MAPS AB The Background Emission Anisotropy Scanning Telescope (BEAST) is a 2.2 m off-axis telescope with an eight-element mixed Q-band (38-45 GHz) and Ka-band (26-36 GHz) focal plane, designed for balloon-borne and ground-based studies of the cosmic microwave background (CMB). Here we present the CMB angular power spectrum calculated from 682 hr of data observed with the BEAST instrument. We use a binned pseudo-C-l estimator (the MASTER method). We find results that are consistent with other determinations of the CMB anisotropy for angular wavenumbers l between 100 and 600. We also perform cosmological parameter estimation. The BEAST data alone produce a good constraint on Omega(k) = 1 - Omega(tot) = 0.074 +/- 0.070, consistent with a flat universe. A joint parameter estimation analysis with a number of previous CMB experiments produces results consistent with previous determinations. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Milan, Dept Phys, I-20133 Milan, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Fed Itajuba, Dept Quim & Fis, BR-50375009 Itajuba, MG, Brazil. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Calif, White Mt Res Stn, CA 93514 USA. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12245970 Sao Jose Dos Campos, Brazil. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Roma Tor Vergata, Sez INFN, I-00173 Rome, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Illinois, Dept Astron, 1002 W Green St, Urbana, IL 61801 USA. RI Figueiredo, Newton/F-9976-2011; Mejia, Jorge/F-9530-2012; OI WANDELT, Benjamin/0000-0002-5854-8269 NR 21 TC 12 Z9 12 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 93 EP 100 DI 10.1086/429089 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000005 ER PT J AU Meinhold, PR Bersanelli, M Childers, J Figueiredo, N Gaier, TC Halevi, D Huey, GG Kangas, M Lawrence, CR Levy, A Lubin, PM Malaspina, M Mandolesi, N Marvil, J Mejia, J Natoli, P O'Dwyer, I O'Neill, H Parendo, S Pina, A Seiffert, MD Stebor, NC Tello, C Villa, F Villela, T Wade, LA Wandelt, BD Williams, B Wuensche, CA AF Meinhold, PR Bersanelli, M Childers, J Figueiredo, N Gaier, TC Halevi, D Huey, GG Kangas, M Lawrence, CR Levy, A Lubin, PM Malaspina, M Mandolesi, N Marvil, J Mejia, J Natoli, P O'Dwyer, I O'Neill, H Parendo, S Pina, A Seiffert, MD Stebor, NC Tello, C Villa, F Villela, T Wade, LA Wandelt, BD Williams, B Wuensche, CA TI A map of the cosmic microwave background from the BEAST experiment SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmic microwave background; cosmology : observations ID ANISOTROPY POWER SPECTRUM; SCANNING-TELESCOPE BEAST; PROBE WMAP OBSERVATIONS; EMISSION; RESOLUTION; RADIATION; SKY AB We present the first sky maps from the BEAST (Background Emission Anisotropy Scanning Telescope) experiment. BEAST consists of a 2.2 m off-axis Gregorian telescope fed by a cryogenic millimeter wavelength focal plane currently consisting of six Q band (40 GHz) and two Ka band (30 GHz) scalar feed horns feeding cryogenic HEMT amplifiers. Data were collected from two balloon-borne flights in 2000, followed by a lengthy ground observing campaign from the 3.8 km altitude University of California White Mountain Research Station. This paper reports the initial results from the ground-based observations. The instrument produced an annular map covering the sky over 33 degrees < delta < 42 degrees. The maps cover an area of 2470 deg(2) with an effective resolution of 23' FWHM at 40 GHz and 30' at 30 GHz. The map rms (smoothed to 300 and excluding Galactic foregrounds) is 57 +/- 5 mu K (Rayleigh-Jeans) at 40 GHz. Comparison with the instrument noise and correcting for 5% atmospheric attenuation gives a cosmic signal rms contribution of 29 +/- 3 mu K (R-J) or 30 +/- 3 mu K relative to a Planck blackbody of 2.7 K. An estimate of the actual cosmic microwave background (CMB) sky signal requires taking into account the l space filter function of our experiment and analysis techniques, carried out in a companion paper. In addition to the robust detection of CMB anisotropies, we find a strong correlation between small portions of our maps and features in recent H alpha maps. In this work we describe the data set and analysis techniques leading to the maps, including data selection, filtering, pointing reconstruction, mapmaking algorithms, and systematic effects. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif, White Mt Res Stn, CA 93514 USA. Univ Calif Santa Barbara, Ctr High Altitude Astrophys, Santa Barbara, CA 93106 USA. Univ Milan, I-20133 Milan, Italy. Univ Fed Itajuba, Dept Quim & Fis, BR-37500903 Itajuba, MG, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12210070 Sao Jose Dos Campos, SP, Brazil. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Roma Tor Vergata, Sez INFN, I-00173 Rome, Italy. CALTECH, Dept Appl Phys, Pasadena, CA 91125 USA. RP Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RI Figueiredo, Newton/F-9976-2011; Mejia, Jorge/F-9530-2012; OI WANDELT, Benjamin/0000-0002-5854-8269; Villa, Fabrizio/0000-0003-1798-861X NR 27 TC 10 Z9 10 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 101 EP 108 DI 10.1086/429088 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000006 ER PT J AU Mejia, J Bersanelli, M Burigana, C Childers, J Figueiredo, N Kangas, M Lubin, P Maino, D Mandolesi, N Marvil, J Meinhold, P O'Dwyer, I O'Neill, H Platania, P Seiffert, M Stebor, N Tello, C Villela, T Wandelt, B Wuensche, CA AF Mejia, J Bersanelli, M Burigana, C Childers, J Figueiredo, N Kangas, M Lubin, P Maino, D Mandolesi, N Marvil, J Meinhold, P O'Dwyer, I O'Neill, H Platania, P Seiffert, M Stebor, N Tello, C Villela, T Wandelt, B Wuensche, CA TI Galactic foreground contribution to the BEAST cosmic microwave background anisotropy maps SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmic microwave background; cosmology : observations; ISM : structure ID SCANNING-TELESCOPE BEAST; SKY MAPS; FULL-SKY; EMISSION; DUST; TEMPLATE AB We report limits on the Galactic foreground emission contribution to the Background Emission Anisotropy Scanning Telescope (BEAST) Ka- and Q-band CMB anisotropy maps. We estimate the contribution from the cross-correlations between these maps and the foreground emission templates of an H alpha map, a destriped version of the Haslam et al. 408 MHz map, and a combined 100 mu m IRAS DIRBE map. Our analysis samples the BEAST similar to 10 degrees declination band into 24 one-hour (R. A.) wide sectors with similar to 7900 pixels each, where we calculate (1) the linear correlation coefficient between the anisotropy maps and the templates; (2) the coupling constants between the specific intensity units of the templates and the antenna temperature at the BEAST frequencies; and (3) the individual foreground contributions to the BEAST anisotropy maps. The peak sector contributions of the contaminants in the Ka-band are of 56.5% free-free with a coupling constant of 8.3 +/- 0.4 mu K R-1, and 67.4% dust with 45.0 +/- 2.0 mu K MJy(-1) sr(-1). In the Q band the corresponding values are of 64.4% free-free with 4.1 +/- 0.2 mu K R-1 and 67.5% dust with 24.0 +/- 1.0 mu K MJy(-1) sr(-1). Using a lower limit of 10% in the relative uncertainty of the coupling constants, we can constrain the sector contributions of each contaminant in both maps to <20% in 21 (free-free), 19 (dust), and 22 (synchrotron) sectors. At this level, all these sectors are found outside of the vertical bar b vertical bar = 14.degrees 6 region. By performing the same correlation analysis as a function of Galactic scale height, we conclude that the region within b = +/- 17.degrees 5 should be removed from the BEAST maps for CMB studies in order to keep individual Galactic contributions below similar to 1% of the map's rms. C1 Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12210070 Sao Jose Dos Campos, SP, Brazil. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Fed Itajuba, Dept Quim & Fis, BR-37500903 Itajuba, MG, Brazil. Univ Calif, White Mt Res Stn, CA 93514 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Inst Nacl Pesquisas Espaciais, Div Astrofis, Caixa Postal 515, BR-12210070 Sao Jose Dos Campos, SP, Brazil. EM mejia@das.inpe.br RI Figueiredo, Newton/F-9976-2011; Mejia, Jorge/F-9530-2012; OI Burigana, Carlo/0000-0002-3005-5796; WANDELT, Benjamin/0000-0002-5854-8269 NR 25 TC 9 Z9 9 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 109 EP 117 DI 10.1086/429090 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000007 ER PT J AU Figueiredo, N Bersanelli, M Childers, J D'Arcangelo, O Halevi, D Janssen, M Kedward, K Lemaster, N Lubin, P Mandolesi, N Marvil, J Meinhold, P Mejia, J Mennella, A Natoli, P O'Neil, H Pina, A Pryor, M Sandri, M Simonetto, A Sozzi, C Tello, C Villa, F Villela, T Williams, B Wuensche, CA AF Figueiredo, N Bersanelli, M Childers, J D'Arcangelo, O Halevi, D Janssen, M Kedward, K Lemaster, N Lubin, P Mandolesi, N Marvil, J Meinhold, P Mejia, J Mennella, A Natoli, P O'Neil, H Pina, A Pryor, M Sandri, M Simonetto, A Sozzi, C Tello, C Villa, F Villela, T Williams, B Wuensche, CA TI The optical design of the Background Emission Anisotropy Scanning Telescope (BEAST) SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmic microwave background; cosmology : observations; telescopes ID ANTENNAS AB We present the optical design of the Background Emission Anisotropy Scanning Telescope (BEAST), an off-axis Gregorian telescope designed to measure the angular distribution of the cosmic microwave background radiation (CMBR) at 30 and 41.5 GHz on angular scales ranging from 20' to 10 degrees. The aperture of the telescope is 1.9 m, and our design meets the strict requirements imposed by the scientific goals of the mission: the beam size is 200 at 41.5 GHz and 260 at 30 GHz, while the illumination at the edge of the mirrors is lower than -30 dB for the central horn. The primary mirror is an off-axis section of a paraboloid, and the secondary an off-axis section of an ellipsoid. A spinning flat mirror located between the sky and the primary provides a two-dimensional chop by rotating the beams around an ellipse on the sky. BEAST uses a receiver array of cryogenic low noise InP High Electron Mobility Transistor (HEMT) amplifiers. The baseline array has seven horns matched to one amplifier each and one horn matched to two amplifiers (two polarizations) for a total of nine amplifiers. Two horns operate around 30 GHz, and six operate around 41.5 GHz. Subsequent campaigns will include 90 GHz and higher frequency channels. C1 Univ Fed Itajuba, Dept Quim & Fis, BR-37500903 Itajuba, MG, Brazil. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CNR, IFP, I-20125 Milan, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Barbara, Dept Mech Engn, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Ctr High Altitude Astrophys White Mt, Santa Barbara, CA 93106 USA. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12210070 Sao Jose Dos Campos, SP, Brazil. CNR, IASF, I-20133 Milan, Italy. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Roma Tor Vergata, Sez INFN, I-00173 Rome, Italy. Composite Opt Inc, San Diego, CA USA. RP Univ Fed Itajuba, Dept Quim & Fis, Caixa Postal 50, BR-37500903 Itajuba, MG, Brazil. EM newton@unifei.edu.br RI Figueiredo, Newton/F-9976-2011; Sozzi, Carlo/F-4158-2012; Mejia, Jorge/F-9530-2012; OI Sozzi, Carlo/0000-0001-8951-0071; Sandri, Maura/0000-0003-4806-5375; Villa, Fabrizio/0000-0003-1798-861X NR 9 TC 8 Z9 8 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 118 EP 123 DI 10.1086/429091 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000008 ER PT J AU Childers, J Bersanelli, M Figueiredo, N Gaier, TC Halevi, D Kangas, M Levy, A Lubin, PM Malaspina, M Mandolesi, N Marvil, J Meinhold, PR Mejia, J Natoli, P O'Neill, H Parendo, S Seiffert, MD Stebor, NC Villa, F Villela, T Williams, B Wuensche, CA AF Childers, J Bersanelli, M Figueiredo, N Gaier, TC Halevi, D Kangas, M Levy, A Lubin, PM Malaspina, M Mandolesi, N Marvil, J Meinhold, PR Mejia, J Natoli, P O'Neill, H Parendo, S Seiffert, MD Stebor, NC Villa, F Villela, T Williams, B Wuensche, CA TI The Background Emission Anisotropy Scanning Telescope (BEAST) instrument description and performances SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE cosmology : observations ID POWER SPECTRUM AB The Background Emission Anisotropy Scanning Telescope (BEAST) is a millimeter wavelength experiment designed to generate maps of fluctuations in the cosmic microwave background (CMB). The telescope is composed of an off-axis Gregorian optical system with a 2.2 m primary that focuses the collected microwave radiation onto an array of cryogenically cooled high electron mobility transistor (HEMT) receivers. This array is composed of six corrugated scalar feed horns in the Q band (38 to 45 GHz) and two more in the Ka band (26 to 36 GHz) with one of the six Q-band horns connected to an ortho-mode transducer for extraction of both polarizations incident on the single feed. The system has a minimum beam size of 200 with an average sensitivity of 900 mu K root s per receiver. This paper describes the design and performance of the BEAST instrument and provides the details of subsystems developed and used toward the goal of generating a map of CMB fluctuations on 200 scales with sensitivity in l space between l similar to 100 and l similar to 500. A map of the CMB centered on the north celestial pole has been generated from the BEAST telescope in a 9 degrees wide annulus at declination 37 degrees with a typical pixel error of 57 +/- 5 mu K when smoothed to 300 resolution. A brief summary of the map and results generated by an observing campaign at the University of California White Mountain Research Station are also included. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Milan, Dept Phys, I-20133 Milan, Italy. Univ Fed Itajuba, Dept Quim & Fis, BR-37500903 Itajuba, MG, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Roma Tor Vergata, Sez INFN, I-00173 Rome, Italy. Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12210070 Sao Jose Dos Campos, SP, Brazil. CNR, IFP, I-20125 Milan, Italy. RP Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RI Figueiredo, Newton/F-9976-2011; Mejia, Jorge/F-9530-2012; OI Villa, Fabrizio/0000-0003-1798-861X NR 19 TC 9 Z9 9 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2005 VL 158 IS 1 BP 124 EP 138 DI 10.1086/429092 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922AF UT WOS:000228807000009 ER PT J AU D'Andrea, SE Perusek, GP Rajulu, S Perry, J Davis, BL AF D'Andrea, SE Perusek, GP Rajulu, S Perry, J Davis, BL TI Jumping in simulated and true microgravity: Response to maximal efforts with three landing types SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE exercise countermeasures; musculoskeletal loading; microgravity simulators; biomechanics ID GROUND REACTION FORCES; RANDOMIZED CONTROLLED TRIAL; HIGH-IMPACT EXERCISE; BONE MASS; BED-REST; LOCOMOTION; GRAVITY; PERSPECTIVE; DENSITY; WOMEN AB Background: Exercise is a promising countermeasure to the physiological deconditioning experienced in microgravity, but has not proven effective in eliminating the ongoing loss of bone mineral, most likely due to the lack of high-impact forces and loading rates during in-flight activity. We wanted to determine lower-extremity response to high-impact jumping exercises in true and simulated microgravity and establish if 1-G force magnitudes can be achieved in a weightless environment. Methods: Jumping experiments were performed in a ground-based zero-gravity simulator (ZGS) in 1 G, and during parabolic flight with a gravity-replacement system. There were 12 subjects who participated in the study, with 4 subjects common to both conditions. Force, loading rates, jump height, and kinematics were analyzed during jumps with three distinct landings: two-footed toe-heel, one-footed toe-heel, and flat-footed. Gravity replacement loads of 45%, 60%, 75%, and 100% bodyweight were used in the ZGS; because of time constraints, these loads were limited to 60% and 75% bodyweight in parabolic flight. Results: Average peak ground-reaction forces during landing ranged between 1902 +/- 607 and 2631 +/- 663 N in the ZGS and between 1683 +/- 807and 2683 +/- 1174 N inthe KC-135. No significant differences were found between the simulated and true microgravity conditions, but neither condition achieved the magnitudes found in 1 G. Conclusion: Data support the hypothesis that jumping exercises can impart high-impact forces during weightlessness and that the custom-designed ZGS will replicate what is experienced in true microgravity. C1 Cleveland Clin Fdn, Dept Biomed Engn, Cleveland, OH USA. NASA, Glenn Res Ctr, Engn Design & Anal Div, Cleveland, OH USA. NASA, Lyndon B Johnson Space Ctr, Anthropometry & Biomech Facil, Houston, TX USA. RP D'Andrea, SE (reprint author), Afferent Corp, 275 Westminster St,Suite 500, Providence, RI 02903 USA. EM susan_dandrea@afferentcorp.com NR 27 TC 2 Z9 2 U1 0 U2 4 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 2005 VL 76 IS 5 BP 441 EP 447 PG 7 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 922XC UT WOS:000228872200004 PM 15892541 ER PT J AU Strauss, S Krog, RL Feiveson, AH AF Strauss, S Krog, RL Feiveson, AH TI Extravehicular mobility unit training and astronaut injuries SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE astronaut training; extravehicular activity; spacesuit; systems engineering; training analysis AB Background: Astronaut spacewalk training can result in a variety of symptom complaints and possible injuries. This study quantified and characterized signs, symptoms, and injuries resulting from extravehicular activity spacesuit training at NASA's Neutral Buoyancy Laboratory, Johnson Space Center, Houston, TX, immersion facility. Methods: We identified the frequency and incidence of symptoms by location, mechanisms of injury, and effective countermeasures. Recommendations were made to improve injury prevention, astronaut training, test preparation, and training hardware. At the end of each test, a questionnaire was completed documenting signs and symptoms, mechanisms of injury, and countermeasures. Results: Of the 770 tests, there were 190 in which suit symptoms were reported (24.6%). There were a total of 352 reported suit symptom comments. Of those symptoms, 166 were in the hands (47.16%), 73 were in the shoulders (20.7%), and 40 were in the feet (11.4%). Others ranged from 6.0% to 0.28%, respectively, from the legs, arms, neck, trunk, groin, and head. Causal mechanisms for the hands included moisture and hard glove contacts resulting in fingernail injuries; in the shoulders, hard contact with suit components and strain mechanisms; and in the feet, hard boot contact. The severity of symptoms was highest in the shoulders, hands, and feet. Conclusions: Most signs and symptoms were mild, self-limited, of brief duration, and were well controlled by available countermeasures. Some represented the potential for significant injury with consequences affecting astronaut health and performance. Correction of extravehicular activity training-related injuries requires a multidisciplinary approach to improve prevention, medical intervention, astronaut training, test planning, and suit engineering. C1 NASA, Johnson Space Ctr, Neutral Buoyancy Lab, Kelsey Seybold Flight Surg,Sonny Ctr Training Fac, Houston, TX 77058 USA. RP Strauss, S (reprint author), NASA, Johnson Space Ctr, Neutral Buoyancy Lab, Kelsey Seybold Flight Surg,Sonny Ctr Training Fac, SD37,2101 NASA Rd 1, Houston, TX 77058 USA. EM samuel.strauss@jsc.nasa.gov NR 27 TC 9 Z9 10 U1 0 U2 3 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 2005 VL 76 IS 5 BP 469 EP 474 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 922XC UT WOS:000228872200008 PM 15892545 ER PT J AU Pierson, DL Stowe, RP Phillips, TM Lugg, DJ Mehta, SK AF Pierson, DL Stowe, RP Phillips, TM Lugg, DJ Mehta, SK TI Epstein-Barr virus shedding by astronauts during space flight SO BRAIN BEHAVIOR AND IMMUNITY LA English DT Article DE antibody; DNA; viral; herpesvirus; Epstein-Barr virus; polymerase chain reaction; stress; weightlessness ID POLYMERASE-CHAIN-REACTION; CELL-MEDIATED-IMMUNITY; DURATION MISSIONS; STRESS; REACTIVATION; NEUROPEPTIDES; SPACEFLIGHT; PLASMA; RADIOIMMUNOASSAY; CYTOMEGALOVIRUS AB Patterns of Epstein-Barr virus (EBV) reactivation in 32 astronauts and 18 healthy age-matched control subjects were characterized by quantifying EBV shedding. Saliva samples were collected from astronauts before, during, and after 10 space shuttle missions of 5-14 days duration. At one time point or another, EBV was detected in saliva from each of the astronauts. Of 1398 saliva specimens from 32 astronauts, polymerase chain reaction analysis showed that 314 (23%) were positive for EBV DNA. Examination by flight phase showed that 29% of the saliva specimens collected from 28 astronauts before flight were positive for EBV DNA, as were 16% of those collected from 25 astronauts during flight and 16% of those collected after flight from 23 astronauts. The mean number of EBV copies from samples taken during the flights was 417 per mL, significantly greater (p <.05) than the number of viral copies from the preflight (40) and postflight (44) phases. In contrast, the control subjects shed EBV DNA with a frequency of 3.7% and mean number of EBV copies of 40 per mL of saliva. Ten days before flight and on landing day, titers of antibody to EBV viral capsid antigen were significantly (p <.05) greater than baseline levels. On landing day, urinary levels of cortisol and catecholamines, were greater than their preflight values. In a limited study (n = 5), plasma levels of substance P and other neuropeptides were also greater on landing day. Increases in the number of viral copies and in the amount of EBV-specific antibody were consistent with EBV reactivation before, during, and after space flight. (C) 2004 Elsevier Inc. All rights reserved. C1 Enterprise Advisory Serv Inc, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Texas, Med Branch, Dept Pathol, Galveston, TX 77550 USA. NIH, Div Bioengn & Phys SCi, ORS, OD, Bethesda, MD 20892 USA. NASA Headquarters, Washington, DC USA. RP Mehta, SK (reprint author), Enterprise Advisory Serv Inc, Houston, TX USA. EM smehta@ems.jsc.nasa.gov NR 37 TC 75 Z9 77 U1 0 U2 12 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0889-1591 J9 BRAIN BEHAV IMMUN JI Brain Behav. Immun. PD MAY PY 2005 VL 19 IS 3 BP 235 EP 242 DI 10.1016/j.bbi.2004.08.001 PG 8 WC Immunology; Neurosciences SC Immunology; Neurosciences & Neurology GA 915OG UT WOS:000228313000008 PM 15797312 ER PT J AU Jin, M Shepherd, JM AF Jin, M Shepherd, JM TI Inclusion of urban landscape in a climate model - How can satellite data help? SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material ID TEMPERATURE; MODIS; PRODUCTS; CLOUD C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jin, M (reprint author), Univ Maryland, Dept Meteorol, Coll Pk, College Pk, MD 20742 USA. EM mjin@atmos.umd.edu NR 18 TC 42 Z9 46 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 2005 VL 86 IS 5 BP 681 EP 689 DI 10.1175/BAMS-86-5-681 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 930LH UT WOS:000229416900023 ER PT J AU Watson, JW Epperly, SP Shah, AK Foster, DG AF Watson, JW Epperly, SP Shah, AK Foster, DG TI Fishing methods to reduce sea turtle mortality associated with pelagic longlines SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID RELEASE FISHERIES; HOOK PERFORMANCE; CARETTA-CARETTA; NORTH-ATLANTIC; CIRCLE HOOK; LOGGERHEAD; MARINE; STAGE AB Changes in hook design and bait type were investigated as measures to reduce the bycatch of sea turtles on pelagic longlines in the western North Atlantic Ocean. Specifically, the effectiveness of 18/0 circle hooks and mackerel (Scomber scombrus) bait was evaluated with respect to reducing sea turtle interactions and maintaining swordfish (Xiphias gladius) and tuna (Thunnus spp.) catch rates. Individually, circle hooks and mackerel bait significantly reduced both loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtle bycatch. Circle hooks also significantly reduced the rate of hook ingestion by the loggerheads, potentially reducing postrelease mortality. The combination of circle hooks and mackerel bait was even more effective for loggerhead turtles and had no negative effect on swordfish catch. These modifications in fishing methods, in conjunction with tools developed to remove hooks and line from the turtles, significantly reduced the capture rate of sea turtles and potentially the post-hooking mortality of those that were caught and did not negatively impact the primary target species catch rate. In addition, these mitigation measures have the potential to reduce mortality of sea turtles and other bycatch species worldwide. C1 NOAA, Natl Marine Fisheries Serv, Mississippi Labs, Pascagoula, MS 39568 USA. NOAA, Natl Marine Fisheries Serv, Miami, FL 33149 USA. Merck Res Labs, Rahway, NJ 07065 USA. RP Watson, JW (reprint author), NOAA, Natl Marine Fisheries Serv, Mississippi Labs, 3209 Frederic St, Pascagoula, MS 39568 USA. EM john.watson@noaa.gov NR 50 TC 182 Z9 201 U1 7 U2 55 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAY PY 2005 VL 62 IS 5 BP 965 EP 981 DI 10.1139/F05-004 PG 17 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 932ZX UT WOS:000229594600002 ER PT J AU Zak, M AF Zak, M TI Stochastic representation of chaos using terminal attractors SO CHAOS SOLITONS & FRACTALS LA English DT Article ID DYNAMICS AB A nonlinear version of the Liouville equation based upon terminal attractors is proposed for describing post-instability motions of dynamical systems with exponential divergence of trajectories such as those leading to chaos and turbulence. As a result, the post-instability motions are represented by expectations, variances, and higher moments of the state variables as functions of time. The proposed approach can be applied to conservative chaos, and in particular, to n-bodies problem, as well as to dissipative systems, and in particular, to chaotic attractors and turbulence. (C) 2004 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mzak@jpl.nasa.gov NR 5 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD MAY PY 2005 VL 24 IS 3 BP 863 EP 868 DI 10.1016/j.chaos.2004.09.098 PG 6 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 897TD UT WOS:000227027200017 ER PT J AU Willis, P Boucher, C Fagard, H Altamimi, Z AF Willis, P Boucher, C Fagard, H Altamimi, Z TI Geodetic applications of the DORIS system at the French 'Institut geographique national' SO COMPTES RENDUS GEOSCIENCE LA French DT Article DE satellite geodesy; DORIS; terrestrial reference frame; satellite positioning; GPS ID TERRESTRIAL REFERENCE FRAME; OBSERVING SYSTEM; GPS; SERVICE; MISSION; GRACE AB Geodetic applications of the DORIS system at the French 'Institut geographique national'. IGN is in charge of the installation and maintenance of the DORIS orbit determination network. More recently, in collaboration with JPL, precise geodetic computations were performed. The goal of this paper is to recall the various historic contributions of IGN to the DORIS system in their international context and then to describe a new estimation technique developed for a multi-satellite mode, making full profit of a better modeling for satellites and ground clocks as well as tropospheric correction parameters. Derived geodetic results demonstrate a precision in the order of I cm for station positions. (c) 2005 Academie des sciences. Publie par Elsevier SAS. Tons droits reserves. C1 Inst Geog Natl, Direct Tech, F-94160 St Mande, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Conseil Gen Ponts & Chaussees, F-92055 La Defense, France. Inst Geog Natl, Serv Geodesie & Nivellement, F-94160 St Mande, France. Inst Geog Natl, ENSG, LAREG, F-77455 Marne La Vallee, France. RP Willis, P (reprint author), Inst Geog Natl, Direct Tech, 2 Av Pasteur,BP 68, F-94160 St Mande, France. EM pascal.willis@ign.fr RI Willis, Pascal/A-8046-2008; Altamimi, Zuheir/A-4168-2009; Boucher, Claude/A-2843-2011 OI Willis, Pascal/0000-0002-3257-0679; NR 27 TC 48 Z9 48 U1 0 U2 0 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0713 EI 1778-7025 J9 CR GEOSCI JI C. R. Geosci. PD MAY PY 2005 VL 337 IS 7 BP 653 EP 662 DI 10.1016/j.crte.2005.03.002 PG 10 WC Geosciences, Multidisciplinary SC Geology GA 927NY UT WOS:000229201800004 ER PT J AU Gerz, T Holzapfel, F Bryant, W Kopp, K Frech, M Tafferner, A Winckelmans, G AF Gerz, T Holzapfel, F Bryant, W Kopp, K Frech, M Tafferner, A Winckelmans, G TI Research towards a wake-vortex advisory system for optimal aircraft spacing SO COMPTES RENDUS PHYSIQUE LA English DT Article DE aircraft wake vortices; atmosphere; air traffic control; optimal aircraft spacing ID DOPPLER LIDAR; VORTICES; DECAY; MODEL; TURBULENCE; PREDICTION; ATMOSPHERE AB Wake turbulence is a major concern for busy airports since it limits capacity. Solutions for new aircraft staggering procedures are sought which relax the cur-rent separations but keep safety on a high level. Systems which advice air-traffic control on wake-vortex behaviour under present and expected weather conditions will, hopefully, contribute to such a solution. Knowledge on transport and decay of wake vortices in the atmosphere is presented. Concepts and designs of wake-vortex advisory systems in Europe and the USA are outlined. European wake-vortex measurement and prediction campaigns are described where the components of such systems have been tested successfully. C1 Deutsch Zentrum Luft & Raumfahrt, Inst Atmospher Phys, D-82230 Wessling, Germany. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Catholique Louvain, Dept Mech Engn, B-1348 Louvain, Belgium. RP Gerz, T (reprint author), Deutsch Zentrum Luft & Raumfahrt, Inst Atmospher Phys, D-82230 Wessling, Germany. EM Thomas.Gerz@dlr.de NR 72 TC 27 Z9 30 U1 0 U2 3 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1631-0705 J9 CR PHYS JI C. R. Phys. PD MAY-JUN PY 2005 VL 6 IS 4-5 BP 501 EP 523 DI 10.1016/j.crhy.2005.06.002 PG 23 WC Astronomy & Astrophysics; Physics, Multidisciplinary SC Astronomy & Astrophysics; Physics GA 967OB UT WOS:000232099400009 ER PT J AU Ural, A Heber, G Wawrzynek, PA Ingraffea, AR Lewicki, DG Neto, JBC AF Ural, A Heber, G Wawrzynek, PA Ingraffea, AR Lewicki, DG Neto, JBC TI Three-dimensional, parallel, finite element simulation of fatigue crack growth in a spiral bevel pinion gear SO ENGINEERING FRACTURE MECHANICS LA English DT Article DE finite element method; fatigue crack growth; computational fracture mechanics; gears; three-dimensional finite element contact analysis; parallel computation ID STRESS-INTENSITY FACTOR; ENERGY-RELEASE RATE; RIM THICKNESS; PROPAGATION; TOOTH; INTEGRALS; TIP AB This paper summarizes new results for predicting crack shape and fatigue life for a spiral bevel pinion gear using computational fracture mechanics. The predictions are based on linear elastic fracture mechanics theories combined with the finite element method, and incorporating plasticity-induced fatigue crack closure and moving loads. We show that we can simulate arbitrarily shaped fatigue crack growth in a spiral bevel gear more efficiently and with much higher resolution than with a previous boundary-element-based approach [Spievak LE, Wawrzynek PA, Ingraffea AR, Lewicki DG. Simulating fatigue crack growth in spiral bevel gears. Engng Fract Mech 2001;68(1):53-76] using the finite element method along with a better representation of moving loads. Another very significant improvement is the decrease in solution time of the problem by employing a parallel PC-cluster, an approach that is becoming more common in both research and practice. This reduces the computation time for a complete simulation from days to a few hours. Finally, the effect of change in the flexibility of the cracking tooth on the location and magnitude of the contact loads and also on stress intensity factors and fatigue life is investigated. (C) 2004 Elsevier Ltd. All rights reserved. C1 Cornell Fracture Grp, Ithaca, NY 14850 USA. USA, Res Lab, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Fed Univ Ceara, BR-60455760 Fortaleza, Ceara, Brazil. RP Ural, A (reprint author), Cornell Fracture Grp, Rhodes Hall, Ithaca, NY 14850 USA. EM aul4@cornell.edu NR 31 TC 44 Z9 55 U1 2 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PD MAY PY 2005 VL 72 IS 8 BP 1148 EP 1170 DI 10.1016/j.engfracmech.2004.08.004 PG 23 WC Mechanics SC Mechanics GA 904AW UT WOS:000227468400003 ER PT J AU Turkel, E Vatsa, VN AF Turkel, E Vatsa, VN TI Local preconditioners for steady and unsteady flow applications SO ESAIM-MATHEMATICAL MODELLING AND NUMERICAL ANALYSIS-MODELISATION MATHEMATIQUE ET ANALYSE NUMERIQUE LA English DT Article DE Low Mach; preconditioning; Jacobi; Dual time step; compressible Navier Stokes ID NAVIER-STOKES EQUATIONS; FLUID-DYNAMICS; DIFFERENCE; SCHEMES AB Preconditioners for hyperbolic systems are numerical artifacts to accelerate the convergence to a steady state. In addition, the preconditioner should also be included in the artificial viscosity or upwinding terms to improve the accuracy of the steady state solution. For time dependent problems we use a dual time stepping approach. The preconditioner affects the convergence rate and the accuracy of the subiterations within each physical time step. We consider two types of local preconditioners: Jacobi and low speed preconditioning. We can express the algorithm in several sets of variables while using only the conservation variables for the flux terms. We compare the effect of these various variable sets on the efficiency and accuracy of the scheme. C1 Tel Aviv Univ, IL-69978 Tel Aviv, Israel. NIA, Hampton, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Turkel, E (reprint author), Tel Aviv Univ, IL-69978 Tel Aviv, Israel. RI Turkel, Eli/F-6297-2011 OI Turkel, Eli/0000-0003-4273-0303 NR 32 TC 31 Z9 31 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0764-583X J9 ESAIM-MATH MODEL NUM JI ESAIM-Math. Model. Numer. Anal.-Model. Math. Anal. Numer. PD MAY-JUN PY 2005 VL 39 IS 3 BP 515 EP 535 DI 10.1051/m2an:2005021 PG 21 WC Mathematics, Applied SC Mathematics GA 953LB UT WOS:000231076700006 ER PT J AU Choi, SR Nemeth, NN Gyekenyesi, JP AF Choi, SR Nemeth, NN Gyekenyesi, JP TI Exponential slow crack growth of glass and advanced ceramics - dynamic fatigue SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE advanced ceramics; constant stress-rate ('dynamic fatigue') testing; crack-velocity formulations; exponential crack-velocity formulation; slow crack growth ID BRITTLE MATERIALS; INDENTATION FLAWS AB The life prediction analysis based on an exponential crack-velocity formulation was made and examined using a variety of experimental data on glass and advanced structural ceramics in constant stress-rate ('dynamic fatigue') loading at ambient and elevated temperatures. The data fit to the relation of strength versus In (stress rate) was very reasonable for most of the materials. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known a priori to evaluate the important SCG parameter, n, a significant drawback as compared with the conventional power-law crack-velocity formulation. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM sung.r.choi@grc.nasa.gov NR 23 TC 8 Z9 8 U1 0 U2 3 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD MAY PY 2005 VL 28 IS 5 BP 489 EP 497 DI 10.1111/j.1460-2695.2005.00890.x PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 919VC UT WOS:000228644700006 ER PT J AU Brown, II Mummey, D Cooksey, KE AF Brown, II Mummey, D Cooksey, KE TI A novel cyanobacterium exhibiting an elevated tolerance for iron SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE novel cyanobacterium; iron tolerance; iron depositing hot spring; great yellowstone area ID MICROBIAL MATS; SYNECHOCOCCUS; TRANSPORT; BIOAVAILABILITY; TRICHODESMIUM; PHOTOTROPHS; RELEVANCE; GENES; OCEAN AB Studies directed at cyanobacteria inhabiting iron-depositing hot springs may provide insights into the role of both ancient and contemporary cyanobacteria mediated iron transformations. Here we phylogenctically, morphologically and physiologically characterize a novel cyanobacterium isolated from an iron-depositing hot spring. Phylogenetic analyses indicate that the bacterium is a representative of a new genus, exhibiting a maximum 95.2% homology to database sequences. The isolate is a unicellular cyanobacterium with bladder-like cells typically packed as duplexes, or in extracellular polymeric substance covered clumps and small chains without the ability to produce baeocystes. No growth without added combined nitrogen occurred. While requiring relatively large amounts of iron for growth (> 40 mu M), the isolate was shown to facilitate removal of iron from culture media. These results suggest that the isolate may be an important component of an iron-depositing microbial community. The name "Chroogloeocystis siderophila" for this cyanobacterium is proposed. (c) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved. C1 Montana State Univ, Dept Microbiol, Bozeman, MT 59717 USA. Montana State Univ, Thermal Biol Inst, Bozeman, MT 59717 USA. Univ Montana, Microbial Ecol Program, Div Biol Sci, Missoula, MT 59812 USA. RP Brown, II (reprint author), NASA, Lyndon B Johnson Space Ctr, Male Code SA13,2101 NASA Pkwy, Houston, TX 77058 USA. EM igor.i.brownl@jsc.nasa.gov NR 39 TC 15 Z9 19 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD MAY 1 PY 2005 VL 52 IS 3 BP 307 EP 314 DI 10.1016/j.femsec.2004.11.020 PG 8 WC Microbiology SC Microbiology GA 922LE UT WOS:000228838600003 PM 16329916 ER PT J AU Decker, KLM Potter, CS Bebout, BM Des Marais, DJ Carpenter, S Discipulo, M Hoehler, TM Miller, SR Thamdrup, B Turk, KA Visscher, PT AF Decker, KLM Potter, CS Bebout, BM Des Marais, DJ Carpenter, S Discipulo, M Hoehler, TM Miller, SR Thamdrup, B Turk, KA Visscher, PT TI Mathematical simulation of the diel O, S, and C biogeochemistry of a hypersaline microbial mat SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article DE microbial mat; biogeochemistry; modeling; oxygen; sulfur; carbon Microcoleus chthonoplastes; cyanobacteria ID SULFATE-REDUCING BACTERIA; PURPLE SULFUR BACTERIA; DECOMPOSE FATTY-ACIDS; OXIC ANOXIC REGIMENS; SOLAR LAKE SINAI; CYANOBACTERIAL MATS; THIOCAPSA-ROSEOPERSICINA; DESULFOBACTER-POSTGATEI; SULFIDE MICROGRADIENTS; GEN-NOV AB The creation of a mathematical simulation model of photosynthetic microbial mats is important to our understanding of key biogeochemical cycles that may have altered the atmospheres and lithospheres of early Earth. A model is presented here as a tool to integrate empirical results from research on hypersaline mats from Baja California Sur (BCS), Mexico into a computational system that can be used to simulate biospheric inputs of trace gases to the atmosphere. The first version of our model, presented here, calculates fluxes and cycling Of O-2, sulfide, and dissolved inorganic carbon (DIC) via abiotic components and via four major microbial guilds: cyanobacteria (CYA), sulfate reducing bacteria (SRB), purple sulfur bacteria (PSB) and colorless sulfur bacteria (CSB). We used generalized Monod-type equations that incorporate substrate and energy limits upon maximum rates of metabolic processes such as photosynthesis and sulfate reduction. We ran a simulation using temperature and irradiance inputs from data collected from a microbial mat in Guerrero Negro in BCS (Mexico). Model 02, sulfide, and DIC concentration profiles and fluxes compared well with data collected in the field mats. There were some model-predicted features of biogeochemical cycling not observed in our actual measurements. For instance, large influxes and effluxes of DIC across the MBGC mat boundary may reveal previously unrecognized, but real, in situ limits on rates of biogeochemical processes. Some of the short-term variation in field-collected mat 02 was not predicted by MBGC. This suggests a need both for more model sensitivity to small environmental fluctuations and for the incorporation of a photorespiration function into the model. (c) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved. C1 Calif State Univ Monterey Bay, Div Sci & Environm Policy, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Ecol Branch, Moffett Field, CA 94035 USA. Orbital Corp, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94035 USA. CNR, Washington, DC 20001 USA. Univ So Denmark, Odense M, Denmark. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Connecticut, Dept Marine Sci, Groton, CT 06304 USA. RP Des Marais, DJ (reprint author), Calif State Univ Monterey Bay, Div Sci & Environm Policy, Mail Stop 242-4, Moffett Field, CA 94035 USA. EM kdecker@mail.arc.nasa.gov RI Decker, Kelly/J-1831-2012; Thamdrup, Bo/F-3889-2016; OI Thamdrup, Bo/0000-0002-1221-7077; Visscher, Pieter/0000-0001-6911-1532 NR 83 TC 22 Z9 24 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD MAY 1 PY 2005 VL 52 IS 3 BP 377 EP 395 DI 10.1016/j.femsec.2004.12.005 PG 19 WC Microbiology SC Microbiology GA 922LE UT WOS:000228838600009 PM 16329922 ER PT J AU Ghoshal, A Kim, HS Chattopadhyay, A Prosser, WH AF Ghoshal, A Kim, HS Chattopadhyay, A Prosser, WH TI Effect of delamination on transient history of smart composite plates SO FINITE ELEMENTS IN ANALYSIS AND DESIGN LA English DT Article ID ORDER ZIGZAG THEORY; DYNAMIC CHARACTERISTICS; CONTINUOUS SENSOR; BEAMS; WAVES AB The transient analysis of delaminated composite and smart composite plates is studied using a newly developed improved layerwise laminate theory, extended to include large deformation and the interlaminar contact during 'breathing' phenomena in the delaminated zone. The theory is capable of capturing interlaminar shear stresses that are critical to delamination. The presence of multiple, discrete delaminations is modeled through the use of Heaviside step functions. Stress free boundary conditions are enforced at all free surfaces and continuity in displacement field and transverse shear stresses are enforced at each ply level. In modeling piezoelectric composite plates, a coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. Numerical analysis is conducted to investigate the effect of nonlinearity in the transient vibration, attributable to large displacements and rotations and to the coupled effect of the large deformation and bimodular behavior caused by the contact impact of delaminated interfaces. Composite plates with delaminations, subject to external loads and voltage history from surface bonded sensors, are investigated and the results are compared with corresponding linear transient history, experimental results and plates without delamination. © 2004 Elsevier B.V. All rights reserved. C1 United Technol Res Ctr, Struct Integr Grp, E Hartford, CT 06108 USA. Inha Univ, Dept Engn Mech, Inchon 402751, South Korea. Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Branch, Hampton, VA 23681 USA. RP Ghoshal, A (reprint author), United Technol Res Ctr, Struct Integr Grp, E Hartford, CT 06108 USA. EM anindo_ghoshal@yahoo.com RI Kim, Heung Soo /F-6611-2011 OI Kim, Heung Soo /0000-0001-7057-5174 NR 23 TC 29 Z9 30 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-874X J9 FINITE ELEM ANAL DES JI Finite Elem. Anal. Des. PD MAY PY 2005 VL 41 IS 9-10 BP 850 EP 874 DI 10.1016/j.finel.2004.10.006 PG 25 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA 926AR UT WOS:000229095600003 ER PT J AU Herd, CDK Treiman, AH McKay, GA Shearer, CK AF Herd, CDK Treiman, AH McKay, GA Shearer, CK TI Light lithophile elements in martian basalts: Evaluating the evidence for magmatic water degassing SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SHERGOTTY METEORITE; TRACE-ELEMENTS; SNC METEORITES; SILICATE MELT; BORON; CRYSTALLIZATION; CONSTRAINTS; PYROXENES; MARS; PETROGENESIS AB Whether water has played a role in the petrogenesis of martian basalts remains a subject of significant debate. Estimates of pre-eruptive water concentrations in martian magmas are impeded by the effects of degassing and shock. However, zoning trends of light lithophile elements (LLE) in pyroxene have been interpreted as evidence for the degassing of magmatic water, on the basis of the soluble behavior of these elements in hydrothermal fluids. We provide ion microprobe analyses of LLE in pyroxene in the Zagami and Shergotty martian basalts, complemented by detailed electron microprobe analyses and major-element X-ray maps, to independently verify the zoning of LLE and its relationship to texture and major-element variations. Our results corroborate previous results; specifically, that Li concentrations are lower in rims than cores of Shergotty and Zagami pyroxene. In contrast, we see no evidence for a core-to-rim decrease in B. In the absence of further data, we interpret the decrease in Li as reflecting either loss after crystallization of pyroxene cores, consistent with magmatic degassing, or the diffusive preferential loss of Li from pyroxene rims, possibly as a result of shock. Because the partitioning behavior of Li between hydrous fluid, minerals, and melt under relevant conditions of pressure, temperature, and melt composition is unknown, the viability of the water degassing hypothesis depends on experiments establishing the compatibility of Li in hydrous fluid associated with martian basaltic melt and the incompatibility of Li in pyroxene at elevated pressures. Copyright (c) 2005 Elsevier Ltd. C1 Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Astromat Res Off, Houston, TX 77058 USA. Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Univ Alberta, Dept Earth & Atmospher Sci, 1-26 Earth Sci Bldg, Edmonton, AB T6G 2E3, Canada. EM herd@ualberta.ca NR 30 TC 27 Z9 27 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY 1 PY 2005 VL 69 IS 9 BP 2431 EP 2440 DI 10.1016/j.gca.2004.10.030 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 922AK UT WOS:000228807800019 ER PT J AU Anderson, RC AF Anderson, RC CA Athena Sci Team TI New results from the robotic exploration of Mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM robert.c.anderson@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A531 EP A531 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701444 ER PT J AU Bonifacie, M Jendrzejewski, N Agrinier, P Monnin, C Laverne, C Coleman, M Charlou, JL Javoy, M AF Bonifacie, M Jendrzejewski, N Agrinier, P Monnin, C Laverne, C Coleman, M Charlou, JL Javoy, M TI The behavior of chlorine and delta Cl-37 during the oceanic crust alteration SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. EM bonifaci@ipgp.jussieu.fr; monnin@lmtg.ups-tlse.fr; christine.laverne@univ.u-3mrs.fr; max.coleman@jpl.nasa.gov; charlou@ifremer.fr RI Bonifacie, Magali/A-5656-2011; MONNIN, Christophe/A-5777-2012 OI MONNIN, Christophe/0000-0002-9343-6414 NR 4 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A787 EP A787 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399702344 ER PT J AU Brandon, AD Walker, RJ Puchtel, IS Humayun, M AF Brandon, AD Walker, RJ Puchtel, IS Humayun, M TI Platinum-Osmium isotope evolution of the Earth's mantle SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. Florida State Univ, Dept Geol Sci, Tallahassee, FL 32310 USA. EM alan.d.brandon1@jsc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A392 EP A392 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701171 ER PT J AU Carpenter, PK AF Carpenter, PK TI Quantitative electron probe microanalysis: State of the art SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 NASA, George C Marshall Space Flight Ctr, BAE Syst, XD42, Huntsville, AL 35812 USA. EM paul.carpenter@msfc.nasa.gov NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A587 EP A587 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701549 ER PT J AU Conrad, PG Lane, AL Bhartia, R Hug, WF AF Conrad, PG Lane, AL Bhartia, R Hug, WF TI Optical detection of organic molecules in extreme environments SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Photon Syst Inc, Covina, CA 91722 USA. EM conrad@jpl.nasa.gov; Arthur.L.Lane@jpl.nasa.gov; Rohit.Bhartia@jpl.nasa.gov; W.Hug@photonsystems.com NR 0 TC 1 Z9 1 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A35 EP A35 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700069 ER PT J AU De Yoreo, JJ Chernov, AA Zepeda-Ruiz, LA Wasylenki, LE Elhadj, S Orme, CA Gilmer, G Dove, PM AF De Yoreo, JJ Chernov, AA Zepeda-Ruiz, LA Wasylenki, LE Elhadj, S Orme, CA Gilmer, G Dove, PM TI A kink-site limited model for growth and inhibition of biominerals SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. EM deyoreo1@llnl.gov; alex.chemov@msfc.nasa.gov; zepedaruiz1@llnl.gov; waz@asu.edu; elhadj@vt.edu; orme1@llnl.gov; gilmer1@llnl.gov; dove@vt.edu RI Dove, Patricia/A-7911-2010; Orme, Christine/A-4109-2009 NR 0 TC 1 Z9 1 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A481 EP A481 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701345 ER PT J AU Giannuzzi, LA Friedmann, EI AF Giannuzzi, LA Friedmann, EI TI The characterization of Martian meteorite ALH84001 using focused ion beam specimen preparation and transmission electron microscopy SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 FEI Co, Hillsboro, OR 97124 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM lgiannuzzi@feico.com; ifriedmann@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A804 EP A804 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399702377 ER PT J AU Hand, KP Carlson, RC Chyba, CF AF Hand, KP Carlson, RC Chyba, CF TI Oxidant production via electron bombardment: Progress in experimental simulations of the Europan surface environment SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Stanford Univ, Dept Geog & Environm Sci, Stanford, CA 94305 USA. Jet Prop Lab, Pasadena, CA 91109 USA. SETI Inst, Ctr Study Life Universe, Mountain View, CA 94043 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A198 EP A198 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700385 ER PT J AU Holmden, C Eglington, BM Papanastassiou, DA AF Holmden, C Eglington, BM Papanastassiou, DA TI High mass resolution plasma mass spectrometry of Cr isotopes SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Univ Saskatchewan, Dept Geol Sci, Saskatchewan Isotope Lab, Saskatoon, SK S7N 0W0, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Eglington, Bruce/A-7144-2008 OI Eglington, Bruce/0000-0003-1318-6062 NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A552 EP A552 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701484 ER PT J AU Humayun, M Qin, L Brandon, AD AF Humayun, M Qin, L Brandon, AD TI Implications of mantle Fe/Mn for mantle plumes SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. Florida State Univ, Dept Geol Sci, Tallahassee, FL 32310 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A104 EP A104 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700205 ER PT J AU Keller, LP Flynn, GJ Sutton, SR AF Keller, LP Flynn, GJ Sutton, SR TI Submicrometer-scale minor and trace element mapping in comet dust SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 NASA, Johnson Space Ctr, Code KR, Houston, TX 77058 USA. SUNY Coll Plattsburgh, Dept Phys, Plattsburgh, NY 12901 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. EM Lindsay.P.Keller@jsc.nasa.gov; flynngj@plattsburgh.edu; sutton@cars.uchicago.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A52 EP A52 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700102 ER PT J AU Kotula, PG Keenan, MR Goldstein, JI Carpenter, P AF Kotula, PG Keenan, MR Goldstein, JI Carpenter, P TI STEM and SEM X-Ray spectral imaging with multivariate statistical analysis: Application to the microanalysis of meteorites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Massachusetts, Amherst, MA 01003 USA. NASA, George C Marshall Space Flight Ctr, BAE Syst, SD46, Huntsville, AL 35812 USA. EM pgkotul@sandia.gov; mrkeena@sandia.gov; jig0@ecs.umass.edu; Paul.Carpenter@msfc.nasa.gov NR 5 TC 3 Z9 3 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A588 EP A588 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701551 ER PT J AU Lauretta, DS Ciesla, FJ AF Lauretta, DS Ciesla, FJ TI Origin of water by inward migration of phyllosilicates or hydrous asteroids SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM lauretta@lpl.arizona.edu; ciesla@cosmic.arc.nasa.gov NR 6 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A748 EP A748 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399702269 ER PT J AU Messenger, S AF Messenger, S TI Distinguishing solar and extrasolar origins of submicrometer grains in IDPs SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID ID INTERPLANETARY DUST C1 NASA, Lyndon B Johnson Space Ctr, Robert M Walker Lab Space Sci, Houston, TX 77058 USA. EM scott.r.messenger@nasa.gov NR 6 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A524 EP A524 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701429 ER PT J AU Puchtel, IS Brandon, AD Humayun, M Walker, RJ AF Puchtel, IS Brandon, AD Humayun, M Walker, RJ TI Pt-Re-Os isotope and HSE systematics of 2.8 Ga komatiites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Univ Maryland, Dept Geol, College Pk, MD 20742 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. Florida State Univ, Dept Geol Sci, Tallahassee, FL 32310 USA. EM ipuchtel@umd.edu NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A392 EP A392 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701172 ER PT J AU Raulin, F Israel, G Niemann, H Owen, T AF Raulin, F Israel, G Niemann, H Owen, T TI The astrobiological aspects of Titan: A new vision from Cassini-Huygens SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 CNRS, LISA, Paris, France. Univ Paris 07, Paris, France. Univ Paris 12, Paris, France. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hawaii, IFA, Honolulu, HI 96822 USA. EM raulin@lisa.univ-paris12.fr; guy.israel@aerov.jussieu.fr; hasso.b.niemann@nasa.gov; Owen@hale.ifa.hawaii.edu NR 0 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A528 EP A528 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399701437 ER PT J AU Schulte, M Rogers, KL AF Schulte, M Rogers, KL TI Organic sulfur compounds in extremophile metabolisms SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. EM Mitchell.Schulte@nasa.gov; rogers@levee.wustl.edu NR 3 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A201 EP A201 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700390 ER PT J AU Shafer, JT Neal, CR Brandon, AD AF Shafer, JT Neal, CR Brandon, AD TI The platinum group element and Re-Os isotopic composition of the Emperor Seamount Chain SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Univ Notre Dame, Dept Civil Engn & Geol Sci, Notre Dame, IN 46556 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM jshafer@nd.edu; Neal.1@nd.edu; alan.d.brandon1@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A108 EP A108 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700212 ER PT J AU Wagstaff, J McKay, G Lofgren, G AF Wagstaff, J McKay, G Lofgren, G TI Observation of contact electrification between silicate melt/Pt and mineral/Pt phase interfaces SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Meeting Abstract CT 15th Annual V M Goldschmidt Conference CY MAY, 2005 CL Moscow, ID C1 Lockheed Martin Space Operat, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, KR, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, KT, Houston, TX 77058 USA. EM jerry.h.wagstaff1@jsc.nasa.gov; gordon.a.mckay@nasa.gov; gary.e.lofgren@nasa.gov NR 1 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2005 VL 69 IS 10 SU S BP A49 EP A49 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 930EX UT WOS:000229399700097 ER PT J AU Parnell, J Osinski, GR Lee, P Green, PF Baron, MJ AF Parnell, J Osinski, GR Lee, P Green, PF Baron, MJ TI Thermal alteration of organic matter in an impact crater and the duration of postimpact heating SO GEOLOGY LA English DT Article DE Haughton impact structure; impact craters; biomarkers; thermal maturity; thermal alteration; Mars ID ARCTIC CANADA; KINETIC-MODEL; MATURITY; ORIGIN; REFLECTANCE; MATURATION; GENERATION; LIFE; OILS AB The 24-km-diameter Tertiary Haughton impact structure formed in rocks that contained preexisting liquid hydrocarbons. Biomarker ratios in the hydrocarbons show a consistent pattern of variation in degree of heating across the structure. The heating reached a maximum at the crater center and is attributed to hydrothermal activity following impact. Kinetic modeling suggests a time scale of similar to 5 k.y. for the heating, at a maximum temperature of 210 degrees C. The short time scale suggests that in moderate-sized craters, which are abundant on Mars, heating is not so extensive that fossil or extant organic matter would be obliterated. C1 Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. NASA, SETI, Ames Res Ctr, Moffett Field, CA 94035 USA. Geotrack Int Pty Ltd, Brunswick W, Vic 3055, Australia. Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. RP Parnell, J (reprint author), Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. NR 37 TC 26 Z9 26 U1 1 U2 2 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD MAY PY 2005 VL 33 IS 5 BP 373 EP 376 DI 10.1130/G21204.1 PG 4 WC Geology SC Geology GA 922AW UT WOS:000228809000011 ER PT J AU Crossley, D Hinderer, J Boy, JP Pierce, DW AF Crossley, D Hinderer, J Boy, JP Pierce, DW TI Empirical orthogonal function (EOF) software SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE gravity field; satellite gravimetry; superconducting gravimeters ID ATMOSPHERIC-PRESSURE; GRAVITY VARIATIONS; ENERGY BALANCES; LAND WATER; VARIABILITY; DYNAMICS; HEIGHT; FIELD AB Ground-based gravity observations have the potential to add useful information to the interpretation of data from the new satellite gravity missions (CHAMP, GRACE, GOCE). We examine 4.5 yr of data from eight superconducting gravimeters (SGs) associated with the Global Geodynamics Project (GGP), from 1997 to 2001, and simulate the time variations that might be seen by a satellite. Signals that are removed from the gravity data before spatial averaging are the solid Earth and ocean tides, a global atmospheric loading using a vertical perfect gas law for the atmosphere, International Earth Rotation Service (IERS) polar motion and instrument drift. The 1-d gravity residuals form the basis of an interpolated minimum curvature grid that we spatially average and analyse using both surface polynomials and empirical orthogonal functions (EOFs). A clear annual component is present that, if truly regional, should be easily detectable by a satellite such as GRACE. The signal is consistent with expected continental water storage, which provides some interest for the future comparison of ground and satellite data. C1 St Louis Univ, Dept Earth & Atmospher Sci, St Louis, MO 63103 USA. Inst Phys Globe Strasbourg, EOST, F-67084 Strasbourg, France. NASA, Space Geodesy Branch, Greenbelt, MD USA. RP Crossley, D (reprint author), St Louis Univ, Dept Earth & Atmospher Sci, 3507 Laclede Ave, St Louis, MO 63103 USA. EM crossley@eas.slu.edu RI Boy, Jean-Paul/E-6677-2017 OI Boy, Jean-Paul/0000-0003-0259-209X NR 27 TC 27 Z9 27 U1 0 U2 8 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD MAY PY 2005 VL 161 IS 2 BP 257 EP 264 DI 10.1111/j.1365-246X.2005.02586.x PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 921DR UT WOS:000228744900001 ER PT J AU Pasek, MA Milsom, JA Ciesla, FJ Lauretta, DS Sharp, CM Lunine, JI AF Pasek, MA Milsom, JA Ciesla, FJ Lauretta, DS Sharp, CM Lunine, JI TI Sulfur chemistry with time-varying oxygen abundance during Solar System formation SO ICARUS LA English DT Article DE solar nebulae; meteorites; cosmochemistry; Jupiter ID ENSTATITE CHONDRITES; CHEMICAL-EQUILIBRIUM; SPECTROSCOPIC DATA; SULFIDE FORMATION; GIANT PLANETS; NEBULA; JUPITER; ATMOSPHERES; ACCRETION; EVOLUTION AB Chemical models of solar nebula chemistry are presented which show the influence of progressive water depletion from the inner solar nebula. The main focus of this work is the equilibrium distribution of S resulting from this process. Under canonical solar nebula conditions, H2S is the dominant S-bearing species in the gas phase and troilite (FeS) is the primary reservoir for S after condensation. As water vapor diffuses out to its condensation front, the equilibrium distribution of S changes significantly. With the removal of water vapor, SiS becomes the most abundant S-bearing gas and MgS and CaS compete with Fes as the main sulfide reservoir. These results allow us to argue that some of the minerals in the enstatite chondrites formed through the heterogeneities associated with the nebular ice condensation front, and that the sulfur abundance in Jupiter reflects a depletion in H2S that is the result of inner nebula sulfur chemistry under varying oxygen abundance. (c) 2004 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Pasek, MA (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM mpasek@lpl.arizona.edu RI Pasek, Matthew/A-7071-2008; OI Pasek, Matthew/0000-0003-1280-9555 NR 58 TC 60 Z9 60 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 1 EP 14 DI 10.1016/j.icarus.2004.10.012 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400001 ER PT J AU Nair, H Summers, ME Miller, CE Yung, YL AF Nair, H Summers, ME Miller, CE Yung, YL TI Isotopic fractionation of methane in the martian atmosphere SO ICARUS LA English DT Article DE exobiology; Mars; atmosphere; photochemistry ID MARS; HDO; CH4 AB The existence of methane in the martian atmosphere may be an indicator Of Subsurface life. Biological processes are known to fractionate the common isotopologues of methane, and hence measuring these isotopic ratios may yield constraints on the nature of the methane Source. Any measurement of the isotopic ratios of atmospheric methane must consider the additional fractionation due to photochemistry in order to quantity the isotopic ratios of the source. Using a one-dimensional photochemical model, we find that photochemistry has a small (4.5 parts per thousand) contribution to delta(13)C(CH4) but has a large (114 parts per thousand) contribution to delta D(CH4). Confirmation of these fractionation values will require additional laboratory data on key model inputs, particularly the ultraviolet absorption cross sections of (CH4)-C-13 and kinetic rate coefficients for the reactions of (CH4)-C-13 and CH3D with OH and O(D-1) at pressures and temperatures relevant to the martian atmosphere. (c) 2004 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Instruments & Sci Data Syst Div, Pasadena, CA 91109 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Nair, H (reprint author), CALTECH, Jet Prop Lab, Instruments & Sci Data Syst Div, Mail Stop 168-414, Pasadena, CA 91109 USA. EM hari.nair@jpl.nasa.gov NR 21 TC 14 Z9 15 U1 1 U2 10 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 32 EP 35 DI 10.1016/j.icarus.2004.10.018 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400004 ER PT J AU Jakosky, BM Mellon, MT Varnes, ES Feldman, WC Boynton, WV Haberle, RM AF Jakosky, BM Mellon, MT Varnes, ES Feldman, WC Boynton, WV Haberle, RM TI Mars low-latitude neutron distribution: Possible remnant near-surface water ice and a mechanism for its recent emplacement SO ICARUS LA English DT Article DE Mars; neutrons; Mars odyssey; water ice; Mars climate ID THERMAL EMISSION SPECTROMETER; SOUTH POLAR-CAP; GROUND ICE; SEASONAL RESERVOIRS; MARTIAN CLIMATE; CYCLE; VAPOR; REGOLITH; BEHAVIOR; CIRCULATION AB surface hydrogen, generally interpreted as resulting from water, in the equatorial and mid-latitudes. Water abundances as great as 10% by mass are inferred. Although such high abundances could be present as adsorbed water in clays or water of hydration of magnesium salts, other measurements suggest that this is not likely. The spatial pattern of where the water is located is not consistent with a dependence on composition, topography, present-day atmospheric water abundance, latitude, or thermophysical properties. The zonal distribution of water shows two maxima and two minima, which is very reminiscent of a distribution that is related to an atmospheric phenomenon. We suggest that the high water abundances could be due to transient ground ice that is present in the top meter of the surface. Ice would be stable at tens-of-centimeters depth at these latitudes if the atmospheric water abundance were more than about several times the present value, much as ice is stable poleward of about +/- 60 degrees latitude for current water abundances. Higher atmospheric water abundances could have resulted relatively recently, even with the present orbital elements, if the south-polar cap had lost its annual covering of CO2 ice; this would have exposed an underlying water-ice cap that could supply water to the atmosphere during Southern summer. If this hypothesis is correct, then (i) the low-latitude water ice is unstable today and is in the process of sublimating and diffusing back into the atmosphere, and (ii) the current configuration of perennial CO2 ice being present on the south cap but not on the north cap might not be representative of the present epoch over the last, say, ten thousand years. (c) 2004 Elsevier Inc. All rights reserved. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jakosky, BM (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA. EM bruce.jakosky@lasp.colorado.edu RI Mellon, Michael/C-3456-2016 NR 49 TC 51 Z9 52 U1 1 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 58 EP 67 DI 10.1016/j.icarus.2004.11.014 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400006 ER PT J AU Hardersen, PS Gaffey, MJ Abell, PA AF Hardersen, PS Gaffey, MJ Abell, PA TI Near-IR spectral evidence for the presence of iron-poor orthopyroxenes on the surfaces of six M-type asteroids SO ICARUS LA English DT Article DE asteroids, composition; mineralogy; spectroscopy; infrared observations; iron meteorites; parent bodies ID RADAR OBSERVATIONS; SPECTROSCOPIC SURVEY; REFLECTANCE SPECTRA; MAINBELT ASTEROIDS; PARENT BODIES; CHONDRITES; BENCUBBIN; METAL; METEORITES; ORIGIN AB The first verifiable near-infrared absorption features in the similar to 0.9-mu m spectral region are reported for Asteroids 16 Psyche, 69 Hesperia, 110 Lydia. 125 Liberatrix. 201 Penelope, and 216 Kleopatra. These weak features (similar to 1-3%) are attributed to orthopyroxenes present on the surfaces of these asteroids. 16 Psyche and 125 Liberatrix have full rotational coverage while 69 Hesperia, 110 Lydia, 201 Penelope, and 2 16 Kleopatra have similar to 75% rotational coverage. Qualitative similar to 2-mu m absorption features are present, but are very weak (< 1%). Absorption band Positions sugggest relatively low abundances of calcium and iron in the pyroxenes. This indicates relatively reducing redox conditions for these asteroids. their parent bodies, and the nebular regions in which they formed. Four potential interpretations for these asteroids include: (1) they are exposed metallic cores or core fragments of differentiated parent bodies with residual orthopyroxene mantle material, (2) they are the result of a smelting-like reaction that converts olivine to pyroxene and metallic iron in the presence of carbon at high temperatures, (3) they are analogs to the primitive metal-rich Bencubbinite meteorites, or (4) they represent metallic Surfaces which have accumulated silicate debris from external sources. Of the two original interpretations for the M-asteroids, the enstatite chondrite interpretation (Chapman and Salisbury, 1973. Icarus 19. 507-522: Gaffey and McCord. 1979, Mineralogical and petrological characterizations of asteroids. In: Gehrels T. (Ed.), Asteroids. Univ. of Arizona Press. Tuscon. pp. 688-723) can be eliminated for these asteroids because the pyroxene in enstatite chondrites is iron-free and does not exhibit Such absorption features. The iron meteorite interpretation remains valid, but with modification. For Asteroids 16 Psyche and 2 16 Kleopatra. these spectral results combined with previous determinations of high radar albedos indicate that these bodies are most probably exposed core fragments of differentiated bodies. M-Asteroids 69 Hesperia, I 10 Lydia, 125 Liberatrix, and 201 Penelope exhibit similar spectral features consistent with exposed core fragments, but radar observations would be needed to confirm a high metal abundance. Observations of M-Asteroids 136 Austria and 325 Heidelberga suggest the absence of absorption features in the similar to 0.4- to similar to 2.5-mu m region within the scatter of the data. Verification of the presence or absence of features across the Surfaces of these two asteroids requires full rotational coverage. The interpretations for these "featureless" M-asteroids are not well-constrained, but remain consistent with the iron meteorite and enstatite chondrite interpretations. (c) 2004 Elsevier Inc. All rights reserved. C1 Univ N Dakota, Dept Space Studies, Grand Forks, ND 58202 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Hardersen, PS (reprint author), Univ N Dakota, Dept Space Studies, Room 526,Box 9008, Grand Forks, ND 58202 USA. EM hardersen@volcano.space.edu RI Hardersen, Paul/N-9343-2014 OI Hardersen, Paul/0000-0002-0440-9095 NR 65 TC 45 Z9 45 U1 1 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 141 EP 158 DI 10.1016/j.icarus.2004.10.017 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400011 ER PT J AU Fernandez, YR Lowry, SC Weissman, PR Mueller, BEA Samarasinha, NH Belton, MJS Meech, KJ AF Fernandez, YR Lowry, SC Weissman, PR Mueller, BEA Samarasinha, NH Belton, MJS Meech, KJ TI New near-aphelion light curves of Comet 2P/Encke SO ICARUS LA English DT Article DE Comets; Encke ID PHOTOMETRIC STANDARD STARS; OUTGASSING ASYMMETRY; CELESTIAL EQUATOR; P-HALLEY; NUCLEUS; ENCKE; DUST; VAPORIZATION; EVOLUTION; SPECTRUM AB We present new, near-aphelion, time series of photometry of Comet 2P/Encke in Cousins-R band. With these light curves we find that the dominant, synodic rotational periodicity is either P(0) = 11.079 +/- 0.009 It or 2 P(0) = 22.158 +/- 0.0 12 h. This is in contrast to data from the 1980s published by others that are consistent with 15.08- and 22.6-h periods. Those periods do not satisfy our phased light curves, and also the 1980s data are not easily reconciled with our periods. This could be due to P/Encke having non-principal axis rotation or due to a drift in the rotation period caused by outgassing torques. We observed the comet at five epochs: July, August, September, and October 2001, and September 2002, and the comet was at times intrinsically brighter than expected for a bare nucleus, due to an apparent contribution from an unresolved coma. Three-quarters of the data were obtained in the second and fifth epochs, and we analyzed these two time series using both the phase-dispersion minimization and "WindowCLEAN" techniques. At both epochs and with both techniques strong periodicities were found near frequencies f(0) = 2.16 d(-1) and f(1) = 4.35 d(-1). By then using visual inspection of the phased light curves to corroborate these frequencies, and by using the data from the other three epochs to properly align light curve features, we were able to derive P(0) and 2P(0) as the only solutions that satisfy all our observations. The periodicity due to f(1) is clearly seen in our data, but we cannot tell from our data alone whether it is a manifestation of the nucleus's shape, non-principal axis rotation, or both. (c) 2004 Elsevier Inc. All rights reserved. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Queens Univ Belfast, Dept Phys, Belfast BT7 1NN, Antrim, North Ireland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Belton Space Explorat Initiat, Tucson, AZ 85716 USA. RP Fernandez, YR (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM yan@ifa.hawaii.edu OI Fernandez, Yanga/0000-0003-1156-9721 NR 39 TC 24 Z9 24 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 194 EP 214 DI 10.1016/j.icarus.2004.10.019 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400016 ER PT J AU Bills, BG AF Bills, BG TI Free and forced obliquities of the Galilean satellites of Jupiter SO ICARUS LA English DT Article DE rotational dynamics; obliquity; Io; Europa; Ganymede; Callisto ID GENERALIZED CASSINIS LAWS; OUTER PLANETS; GRAVITATIONAL TIDES; INTERNAL STRUCTURE; SECULAR ACCELERATION; ORBITAL RESONANCE; TIDAL DISSIPATION; PRECESSION; IO; ORIGIN AB The obliquity, or angular separation between orbit normal and spin pole, is an important parameter for the geodynamics of most So System bodies. Tidal dissipation has driven the obliquities of the Galilean satellites Of Jupiter to small, but non-zero values. We present estimates of the free and forced obliquities of these satellites using a simple secular variation model for the orbits, and spin pole precession rate estimates based on gravity field parameters derived from Galileo spacecraft encounters. The free obliquity values are not well constrained by observations, but are presumed to be very small. The forced obliquity Variations depend only on the orbital variations and the spin pole precession rate parameters, which are quite well known. These variations are large enough to influence spatial and temporal patterns of tidal dissipation and tidal stress. Published by Elsevier Inc. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. RP Bills, BG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM bbills@igpp.ucsd.edu RI Bills, Bruce/C-1156-2008 NR 63 TC 36 Z9 36 U1 0 U2 11 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 233 EP 247 DI 10.1016/j.icarus.2004.10.028 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400019 ER PT J AU Cruikshank, DP Owen, TC Ore, CD Geballe, TR Roush, TL de Bergh, C Sandford, SA Poulet, F Benedix, GK Emery, JP AF Cruikshank, DP Owen, TC Ore, CD Geballe, TR Roush, TL de Bergh, C Sandford, SA Poulet, F Benedix, GK Emery, JP TI A spectroscopic study of the surfaces of Saturn's large satellites: H(2)O ice, tholins, and minor constituents SO ICARUS LA English DT Article DE ices; infrared observations; satellites of Saturn; spectroscopy; surfaces; satellite; organic chemistry ID NEAR-INFRARED SPECTROSCOPY; WATER-ICE; REFLECTANCE SPECTROSCOPY; OPTICAL-CONSTANTS; SPECTRAL REFLECTANCE; REGULAR SATELLITES; CRYSTALLINE WATER; PHYSICAL STATE; GIANT PLANETS; TITAN HAZE AB We present spectra of Saturn's icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, and Hyperion, 1.0-2.5 pm, with data extending to shorter (Mimas and Enceladus) and longer (Rhea and Dione) wavelengths for certain objects. The spectral resolution (R of the data shown here is in the range 800-1000, depending on the specific instrument and configuration used; this is higher than the resolution (R = 225 at 3 mu m) afforded by the Visual-Infrared Mapping Spectrometer on the Cassini spacecraft. All of the spectra are dominated by water ice absorption bands and no other features are clearly identified. Spectra of all of these satellites show the characteristic signature of hexagonal H(2)O ice at 1.65 mu m. We model the leading hemisphere of Rhea in the wavelength range 0.3-3.6 mu m with the Hapke and the Shkuratov radiative transfer codes and discuss the relative merits of the two approaches to fitting the spectrum. In calculations with both codes, the only components used are H(2)O ice, which is the dominant constituent, and a small amount of tholin (Ice Tholin II). Tholin in small quantities (few percent. depending on the mixing mechanism) appears to be an essential component to give the basic red color of the satellite in the region 0.3-1.0 mu m. The quantity and mode of mixing of tholin that can produce the intense coloration of Rhea and other icy satellites has bearing on its likely presence in many other icy bodies of the outer Solar System, both of high and low geometric albedos. Using the modeling codes, we also establish detection limits for the ices of CO (a few weight percent, depending on particle size and mixing), CH(4) (same), and NH(4)OH (0.5 weight percent) in Our globally averaged spectra of Rhea's leading hemisphere. New laboratory spectral data for NH(4)OH are presented for the purpose of detection on icy bodies. These limits for CO(2). CH4. and NH(4)OH on Rhea are also applicable to the other icy satellites for which spectra are presented here. The reflectance spectrum of Hyperion shows evidence for a broad, unidentified absorption band centered at 1.75 pm. (c) 2004 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. SETI Inst, Mountain View, CA 94043 USA. Gemini Observ, Hilo, HI 96720 USA. Observ Paris, F-92195 Meudon, France. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, 245-6, Moffett Field, CA 94035 USA. EM dale.p.cruikshank@nasa.gov OI Benedix, Gretchen/0000-0003-0990-8878 NR 92 TC 67 Z9 67 U1 3 U2 10 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 2005 VL 175 IS 1 BP 268 EP 283 DI 10.1016/j.icarus.2004.09.003 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 921AA UT WOS:000228735400022 ER PT J AU Love, AL Pang, A Kao, DL AF Love, AL Pang, A Kao, DL TI Visualizing spatial multivalue data SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Article C1 Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, NASA Adv Supercomp Div, Ames, IA USA. EM alove@adobe.com; pang@cse..ucsc.edu; David.L.Kao@nasa.gov NR 13 TC 28 Z9 30 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0272-1716 EI 1558-1756 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD MAY-JUN PY 2005 VL 25 IS 3 BP 69 EP 79 DI 10.1109/MCG.2005.71 PG 11 WC Computer Science, Software Engineering SC Computer Science GA 922CN UT WOS:000228813600011 PM 15943090 ER PT J AU Chien, S Cichy, B Davies, A Tran, D Rabideau, G Castano, R Sherwood, R Mandl, D Frye, S Shulman, S Jones, J Grosvenor, S AF Chien, S Cichy, B Davies, A Tran, D Rabideau, G Castano, R Sherwood, R Mandl, D Frye, S Shulman, S Jones, J Grosvenor, S TI An autonomous Earth-observing sensorweb SO IEEE INTELLIGENT SYSTEMS LA English DT Editorial Material ID MODIS C1 CALTECH, Jet Prop Lab, Flight Software Dev & Technol Grp, Pasadena, CA 91125 USA. Goddard Space Flight Ctr, Earth Observing One Mission, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, AI Grp, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Machine Learning Syst Grp, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, OASIS, Pasadena, CA 91125 USA. Goddard Space Flight Ctr, Adv Architectures & Automat Branch, Greenbelt, MD 20771 USA. RP Chien, S (reprint author), CALTECH, Jet Prop Lab, Flight Software Dev & Technol Grp, Pasadena, CA 91125 USA. EM steve.chien@jpl.nasa.gov; benjamin.cichy@jpl.nasa.gov; ashley.davies@jpl.nasa.gov; daniel.tran@jpl.nasa.gov; gregg.rabideau@jpl.nasa.gov; rebecca.castano@jpl.nasa.gov; rob.sherwood@jpl.nasa.gov; dan.mandl@gsfc.nasa.gov; frye@gsfc.nasa.gov; Shulman.1@gsfc.nasa.gov; sandy.grosvenor@gsfc.nasa.gov NR 24 TC 50 Z9 52 U1 0 U2 5 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1541-1672 J9 IEEE INTELL SYST JI IEEE Intell. Syst. PD MAY-JUN PY 2005 VL 20 IS 3 BP 16 EP 24 DI 10.1109/MIS.2005.40 PG 9 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 930SZ UT WOS:000229438700006 ER PT J AU Filman, RE AF Filman, RE TI Patent pending SO IEEE INTERNET COMPUTING LA English DT Editorial Material C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Filman, RE (reprint author), NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. EM filman@computer.org NR 4 TC 0 Z9 0 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1089-7801 J9 IEEE INTERNET COMPUT JI IEEE Internet Comput. PD MAY-JUN PY 2005 VL 9 IS 3 BP 4 EP 7 DI 10.1109/MIC.2005.125 PG 4 WC Computer Science, Software Engineering SC Computer Science GA 925RZ UT WOS:000229072300001 ER PT J AU Deshpande, VM Deshpande, MD AF Deshpande, VM Deshpande, MD TI Study of electromagnetic wave propagation through dielectric slab doped randomly with thin metallic wires using finite element method SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE finite element method (FEM); propagation through random media; reflection and transmission coefficients AB A new numerical simulation method using the finite element methodology (FEM) is presented to study electromagnetic propagation through a dielectric material slab doped randomly with thin and short metallic wires. The FEM approach described in many standard text books and published papers [1], [2] is appropriately modified to account for the presence of thin and short metallic wires. Using this modified FEM approach, the transmission and reflection characteristics of a material slab (homogeneous dielectric slab doped randomly with thin and short metallic wires) placed in an X-band rectangular waveguide are estimated. The estimated results are compared with the numerical results obtained using the CST microwave studio simulation tool [3]. C1 Univ Virginia, Dept Elect & Comp Engn, Charlottesville, VA 22903 USA. NASA, Electromagnet Res Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP Deshpande, VM (reprint author), Univ Virginia, Dept Elect & Comp Engn, Charlottesville, VA 22903 USA. EM vmd3a@virginia.edu; m.d.deshpande@larc.nasa.gov NR 4 TC 5 Z9 5 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD MAY PY 2005 VL 15 IS 5 BP 306 EP 308 DI 10.1109/LMWC.2005.847663 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 923KJ UT WOS:000228908500004 ER PT J AU Ponchak, GE Dalton, E Tentzeris, MM Papapolymerou, J AF Ponchak, GE Dalton, E Tentzeris, MM Papapolymerou, J TI Coupling between microstrip lines with finite width ground plane embedded in thin-film circuits SO IEEE TRANSACTIONS ON ADVANCED PACKAGING LA English DT Article DE coupling; crosstalk; finite-difference time domain (FDTD); microstrip ID RADIATION CHARACTERISTICS; SUBSTRATE; ANTENNA; MODE; RF AB Three-dimensional (3-D) interconnects built upon multiple layers of polyimide are required for constructing 3-D circuits on CMOS (low resistivity) Si wafers, GaAs, and ceramic substrates. Thin-film microstrip lines (TFMS) with finite-width ground planes embedded in the polyimide are often used. However, the closely spaced TFMS lines are susceptible to high levels of coupling, which degrades the circuit performance. In this paper, finite-difference time domain (FDTD) analysis and experimental measurements are used to demonstrate that the ground planes must be connected by via holes to reduce coupling in both the forward and backward directions. Furthermore, it is shown that coupled microstrip lines establish a slotline type mode between the two ground planes and a dielectric waveguide type mode, and that the connected via holes recommended here eliminate these two modes. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 11 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1521-3323 J9 IEEE T ADV PACKAGING JI IEEE Trans. Adv. Packag. PD MAY PY 2005 VL 28 IS 2 BP 320 EP 327 DI 10.1109/TADVP.2005.846933 PG 8 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 924TQ UT WOS:000229003700020 ER PT J AU Zhang, Y Lu, J Pacheco, J Moss, CD Ao, CO Grzegorezyk, TM Kong, JA AF Zhang, Y Lu, J Pacheco, J Moss, CD Ao, CO Grzegorezyk, TM Kong, JA TI Mode-expansion method for calculating electromagnetic waves scattered by objects on rough ocean surfaces SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE electromagnetic wave scattering; method of moments (MoM); mode-expansion method (MEM); rough surface ID FORWARD-BACKWARD METHOD; ACCELERATION AB A mode-expansion method that needs less than 6% the number of unknowns required by conventional method of moments is introduced in calculating two-dimensional electromagnetic wave scattering from perfectly conducting objects on rough ocean surfaces. Modes are selected for dominant propagation waves so that the number of unknowns in the matrix equation are minimized. In the numerical examples, ocean surfaces are modeled as perfectly conducting rough surfaces described by the Pierson-Moskowitz power spectrum. Bistatic radar cross-sections (RCS) of various objects, such as ship-like and low-observable targets, are calculated for a 1-GHz incident plane wave and are validated for accuracy against an iterative MoM solution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. MIT, Elect Res Lab, Cambridge, MA 02139 USA. MIT, Lincoln Lab, Lexington, MA 02420 USA. BAE Syst, Burlington, MA 01803 USA. RP Zhang, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 16 Z9 18 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD MAY PY 2005 VL 53 IS 5 BP 1631 EP 1639 DI 10.1109/TAP.2005.846721 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 924ML UT WOS:000228982800006 ER PT J AU Booske, JH Converse, MC Kory, CL Chevalier, CT Gallagher, DA Kreischer, KE Heinen, VO Bhattacharjee, S AF Booske, JH Converse, MC Kory, CL Chevalier, CT Gallagher, DA Kreischer, KE Heinen, VO Bhattacharjee, S TI Accurate parametric modeling of folded waveguide circuits for millimeter-wave traveling wave tubes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article; Proceedings Paper CT 5th IEEE International Vacuum Electronics Conference (IVEC) CY APR 27-29, 2004 CL Monterey, CA SP IEEE DE folded waveguide; millimeter-wave; numerical simulation; traveling wave tube (TWT) AB In this paper, results of different models are compared for calculating effective, cold-circuit (beam-free) phase velocities and interaction impedances of folded waveguide (FW) slow wave circuits for use in millimeter-wave traveling wave tubes (TWT). These parameters are needed for one-dimensional (1-D) parametric model simulations of FW traveling wave tubes (FWTWTs). The models investigated include approximate analytic expressions, equivalent circuit, three-dimensional (3-D) finite difference, and 3-D finite element. The phase velocity predictions are compared with experimental measurements of a representative FW circuit. The various model results are incorporated into the CHRISTINE1D code to obtain predictions of small signal gain in a 40-55 GHz FWTWT. Comparing simulated and measured frequency-dependent gain provides a sensitive, confirming assessment of the accuracy of the simulation tools. It is determined that the use of parametric 1-D TWT models for accurate, full band predictions of small signal gain in FWTWTs requires knowledge of phase velocity and impedance functions that are accurate to < 0.5% and < 10%. respectively. Saturated gain predictions, being approximately half as sensitive to these parameters, appear to require correct specification of phase velocity and interaction impedance to within similar to 1% and 20%, respectively. Although all models generate sufficiently accurate predictions of the interaction impedance, not all generate sufficiently accurate predictions of the effective axial phase velocity. C1 Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. NASA, Glenn Res Ctr, Analex Corp, Cleveland, OH 44135 USA. Northrop Grumman Corp, Rolling Meadows, IL 60008 USA. RP Booske, JH (reprint author), Univ Wisconsin, Dept Elect & Comp Engn, 1415 Johnson Dr, Madison, WI 53706 USA. EM booske@engr.wisc.edu RI Bhattacharjee, Sudeep/C-7085-2014 OI Bhattacharjee, Sudeep/0000-0002-5369-9818 NR 16 TC 114 Z9 127 U1 3 U2 18 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2005 VL 52 IS 5 BP 685 EP 694 DI 10.1109/TED.2005.845798 PG 10 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 919DY UT WOS:000228599700011 ER PT J AU Nusinovich, GS Carmel, Y Shkvarunets, AG Rodgers, JC Antonsen, TM Granatstein, VL Bliokh, YP Goebel, DM Verboncoeur, JP AF Nusinovich, GS Carmel, Y Shkvarunets, AG Rodgers, JC Antonsen, TM Granatstein, VL Bliokh, YP Goebel, DM Verboncoeur, JP TI The pasotron: Progress in the theory and experiments SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article; Proceedings Paper CT 5th IEEE International Vacuum Electronics Conference (IVEC) CY APR 27-29, 2004 CL Monterey, CA SP IEEE DE ion focusing; microwaves; microwave generation; plasma ID BACKWARD-WAVE OSCILLATORS; MICROWAVE SOURCES; MODE INTERACTION; END REFLECTIONS; ELECTRON-BEAMS; EFFICIENCY AB Plasma-assisted slow-wave oscillators (pasotrons) are unique sources of microwave radiation, in which the beam propagation in the absence of external magnetic fields is provided by the ion focusing and the electron interaction with the RF field is essentially two-dimensional. This paper overviews the results obtained in the last several years and presents recent accomplishments in the theory and experimental performance of the pasotron. In particular, the 50% efficient operation at the 0.5-MW power level and more than 30% efficient operation at more than a 1-MW level are reported. Theoretical results of the analysis of nonstationary self-consistent processes in the beam focusing and transport agree with PIC simulations. The paper also contains the first results of the noise measurements in the pasotron. The paper is focused at describing the progress in the field, and explaining the interesting physical effects and improvements in the device performance without going into details of either the theoretical formalism or experimental parameters. C1 Univ Maryland, Inst Res Elect & Appl Phys, College Pk, MD 20742 USA. Technion Israel Inst Technol, IL-32000 Haifa, Israel. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Berkeley, CA 94702 USA. RP Nusinovich, GS (reprint author), Univ Maryland, Inst Res Elect & Appl Phys, College Pk, MD 20742 USA. RI Bliokh, Yury/A-3743-2013; Nusinovich, Gregory/C-1314-2017; Antonsen, Thomas/D-8791-2017 OI Nusinovich, Gregory/0000-0002-8641-5156; Antonsen, Thomas/0000-0002-2362-2430 NR 33 TC 15 Z9 17 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2005 VL 52 IS 5 BP 845 EP 857 DI 10.1109/TED.2005.845815 PG 13 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 919DY UT WOS:000228599700031 ER PT J AU Njoku, EG Ashcroft, P Chan, TK Li, L AF Njoku, EG Ashcroft, P Chan, TK Li, L TI Global survey and statistics of radio-frequency interference in AMSR-E land observations SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT 8th Specialist Meeting on Microwave Radiometry and Remote Sensing Applications CY FEB 24-27, 2004 CL Univ Rome La Sapienza, Engn Coll, Rome, ITALY HO Univ Rome La Sapienza, Engn Coll DE Advanced Microwave Scanning Radiometer (AMSR); microwave radiometry; microwave remote sensing; radio-frequency interference (RFI) ID SOIL-MOISTURE; RETRIEVAL; EOS AB Radio-frequency interference (RFI) is an increasingly serious problem for passive and active microwave sensing of the Earth. To satisfy their measurement objectives, many spaceborne passive sensors must operate in unprotected bands, and future sensors may also need to operate in unprotected bands. Data from these sensors are likely to be increasingly contaminated by RFI as the spectrum becomes more crowded. In a previous paper we reported on a preliminary investigation of RFI observed over the United States in the 6.9-GHz channels of the Advanced Microwave Scanning Radiometer (AMSR-E) on the Earth Observing System Aqua satellite. Here, we extend the analysis to an investigation of RFI in the 6.9- and 10.7-GHz AMSR-E channels over the global land domain and for a one-year observation period. The spatial and temporal characteristics of the RFI are examined by the use of spectral indices. The observed RFI at 6.9 GHz is most densely concentrated in the United States, Japan, and the Middle East, and is sparser in Europe, while at 10.7 GHz the RF1 is concentrated mostly in England, Italy, and Japan. Classification of RFI using means and standard deviations of the spectral indices is effective in identifying strong RFI. In many cases, however, it is difficult, using these indices, to distinguish weak RFI from natural geophysical variability. Geophysical retrievals using RFI-filtered data may therefore contain residual errors due to weak RFI. More robust radiometer designs and continued efforts to protect spectrum allocations will be needed in future to ensure the viability of spaceborne passive microwave sensing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Remote Sensing Syst, Santa Rosa, CA 95401 USA. USN, Res Lab, Washington, DC 20375 USA. RP Njoku, EG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Xie, Xingmei/G-7311-2011 NR 13 TC 151 Z9 163 U1 0 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2005 VL 43 IS 5 BP 938 EP 947 DI 10.1109/TGRS.2004.837507 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 920ES UT WOS:000228672800003 ER PT J AU Meneghini, R AF Meneghini, R TI A broadband microwave radiometer technique at X-band for rain and drop size distribution estimation SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT 8th Specialist Meeting on Microwave Radiometry and Remote Sensing Applications CY FEB 24-27, 2004 CL Univ Rome La Sapienza, Engn Coll, Rome, ITALY HO Univ Rome La Sapienza, Engn Coll DE airborne radiometer; drop size distribution; microwave radiometry; rain rate estimation; spaceborne radiometer ID RADAR MEASUREMENTS; ATTENUATION; FREQUENCIES AB Radiometric brightness temperatures below about 12 GHz provide accurate estimates of path attenuation through precipitation and cloud water. Multiple brightness temperature measurements at X-band frequencies can be used to estimate rainfall rate and parameters of the drop size distribution once correction for cloud water attenuation is made. Employing a stratiform storm model, calculations of the brightness temperatures at 9.5, 10, and 12 GHz are used to simulate estimates, of path-averaged median mass diameter, number concentration, and rainfall rate. The results indicate that reasonably accurate estimates of rainfall rate and information on the drop size distribution can be derived over ocean under low to moderate wind speed conditions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Robert.Meneghini-1@nasa.gov NR 20 TC 1 Z9 1 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2005 VL 43 IS 5 BP 990 EP 999 DI 10.1109/TGRS.2004.839590 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 920ES UT WOS:000228672800008 ER PT J AU Focardi, P McGrath, WR Neto, A AF Focardi, P McGrath, WR Neto, A TI Design guidelines for terahertz mixers and detectors SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE coplanar waveguide (CPW) lines; hot electron bolometers (HEBs); lens antennas; slot antennas; terahertz frequencies ID ELECTRON-BOLOMETER MIXERS; DIELECTRIC LENSES; SLOT ANTENNAS; 2.5 THZ AB Twin-slot antennas and coplanar waveguides are a popular choice for coupling signals to state-of-the-art mixers and detectors at terahertz frequencies. Although these sensors show promising performance in terms of noise temperature, they usually also show a considerable downward shift in the center frequency of their spectral response, especially when compared with calculations obtained with commonly used simplified models. In this paper, we describe an accurate and complete electromagnetic model of these detectors, which represents a significant improvement over other published approaches. We present the procedure used to obtain a very good agreement between measurements and calculations at terahertz frequencies both in terms of center frequency and bandwidth. The wide variety of measured and calculated data presented in this paper also demonstrates the effectiveness and reliability of the electromagnetic model in all the investigated frequency bands. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. TNO, Defence & Secur, Ctr Appl Sci Res, NL-2597 AK The Hague, Netherlands. RP Focardi, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Paolo.Focardi@jpl.nasa.gov; William.R.McGrath@jpl.nasa.gov; andrea.neto@tno.nl NR 15 TC 12 Z9 12 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 2005 VL 53 IS 5 BP 1653 EP 1661 DI 10.1109/TMTT.2005.847058 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA 925LC UT WOS:000229053600011 ER PT J AU Kusters, JA Trolier-McKinstry, S Maleki, L Ruppel, CCW AF Kusters, JA Trolier-McKinstry, S Maleki, L Ruppel, CCW TI Introduction to the special fiftieth anniversary issue SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Editorial Material C1 Agilent Technol, Cupertino, CA 95014 USA. Penn State Univ, Mat Sci & Engn Dept, University Pk, PA 16802 USA. Penn State Univ, Mat Res Inst, University Pk, PA 16802 USA. CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, Pasadena, CA 91109 USA. EPCOS AG, SAW R&D SAM, D-81671 Munich, Germany. RP Kusters, JA (reprint author), Agilent Technol, Cupertino, CA 95014 USA. OI Trolier-McKinstry, Susan/0000-0002-7267-9281 NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 2005 VL 52 IS 5 BP 692 EP 693 PG 2 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 936MO UT WOS:000229860300001 ER PT J AU Dyson, RW AF Dyson, RW TI Demonstration of ultra hi-fi (UHF) methods SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE CAA; UHF methods; multi-domain spectral methods; CFD ID FINITE-DIFFERENCE SCHEMES; UNSTRUCTURED GRIDS; CONSERVATION-LAWS; EULER EQUATIONS; VOLUME SCHEMES; SIMULATION; COMPUTATIONS; RESOLUTION AB Computational aero-acoustics (CAA) requires efficient, high-resolution simulation tools. Most current techniques utilize finite-difference approaches because high order accuracy is considered too difficult or expensive to achieve with finite volume or finite element methods. However, a novel finite volume approach i.e. ultra hi-fi (UHF) which utilizes Hermite fluxes is presented which can achieve both arbitrary accuracy and fidelity in space and time. The technique can be applied to unstructured grids with some loss of fidelity or with multi-block structured grids for maximum efficiency and resolution. In either paradigm, it is possible to resolve ultra-short waves (defined as waves having wavelengths that are shorter than a grid cell). This is demonstrated here by solving the 4th CAA workshop Category 1 Problem 1. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dyson, RW (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM rodger.w.dyson@nasa.gov NR 24 TC 0 Z9 0 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PD MAY PY 2005 VL 19 IS 4 BP 321 EP 327 DI 10.1080/10618560500214214 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 975YT UT WOS:000232700700005 ER PT J AU Choi, SR Gyekenyesi, JP AF Choi, SR Gyekenyesi, JP TI Load-rate dependency of ultimate tensile strength in ceramic matrix composites at elevated temperatures SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article DE continuous fiber-reinforced ceramic matrix composites; tensile strength; stress rupture; slow crack growth ID SIC/SIC COMPOSITES; STRESS-RUPTURE; CRACK-GROWTH; CREEP AB Ultimate tensile strength of three continuous fiber-reinforced ceramic matrix composites, including SiCf/CAS-II (ID), SiCf/MAS-5 (2D) and SiCf/SiC (2D), was determined as a function of load (test) rate in air at 1100-1200 degrees C. All three composites exhibited a significant dependency of ultimate tensile strength on test rate. The application of the preload technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress) suggested that the overall phenomenological macroscopic failure mechanism of the composites would be a power-law type of slow crack growth or damage evolution/accumulation. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology for ceramic matrix composites, at least for a short range of lifetimes and when ultimate tensile strength is used as a failure criterion. (c) 2004 Elsevier Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), OAI, Cleveland, OH USA. EM sung.r.choi@grc.nasa.gov NR 23 TC 12 Z9 13 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PD MAY PY 2005 VL 27 IS 5 BP 503 EP 510 DI 10.1016/j.ijfatigue.2004.10.001 PG 8 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 904HL UT WOS:000227486600004 ER PT J AU Su, S Dai, W Jordan, PM Mickens, RE AF Su, S Dai, W Jordan, PM Mickens, RE TI Comparison of the solutions of a phase-lagging heat transport equation and damped wave equation SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID COMPOSITE MEDIUM; THERMAL WAVES; PROPAGATION; RESISTANCE; FILMS; METAL AB The phase-lagging equation (PLE) is a new heat conduction equation which is different from the traditional heat equation since there exists a time lag of the heat-flux vector, while the damped wave equation (DWE) is its first-order approximation. In this article, we study the difference between the solutions of the PLE and the DWE by investigating the solutions of a test problem. Results show that the level of the solution obtained by the PLE is smaller in magnitude than the one obtained by the DWE, and that the DWE is a good approximation to the PLE when the time lag is small. (c) 2005 Elsevier Ltd. All rights reserved. C1 Louisiana Tech Univ, Dept Math & Stat, Ruston, LA 71272 USA. USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Clark Atlanta Univ, Dept Phys, Atlanta, GA 30314 USA. RP Dai, W (reprint author), Louisiana Tech Univ, Dept Math & Stat, Ruston, LA 71272 USA. EM dai@coes.latech.edu NR 27 TC 28 Z9 28 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD MAY PY 2005 VL 48 IS 11 BP 2233 EP 2241 DI 10.1016/j.ijheatmasstransfer.2004.12.024 PG 9 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 928BL UT WOS:000229246000011 ER PT J AU Ottens, AK Arkin, CR Griffin, TP Palmer, PT Harrison, WW AF Ottens, AK Arkin, CR Griffin, TP Palmer, PT Harrison, WW TI Ion-molecule reactions in quadrupole ion trap mass spectrometry: implications for lightweight gas analysis SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion trap; ion-molecule reaction; charge-exchange; proton transfer; permanent gas analysis ID PROTON-TRANSFER REACTIONS; HYDROGEN-ATOM TRANSFER; CHEMICAL IONIZATION; ENERGY-DEPENDENCE; H-2 AB The novel application of a quadrupole ion trap mass spectrometer (QITMS) to permanent gas analysis was recently presented by our laboratory. The quantitative performance of the QITMS equaled or surpassed that of other mass analyzers evaluated; however, concern was raised as to the impact of ion-molecule reactions observed within the ion trap. Hydrogen, helium, oxygen, and argon, four permanent gases currently monitored during Space Shuttle launch preparations by the National Aeronautics and Space Administration, were examined in their reactions with common atmospheric and mass spectrometer background components. Rapid charge-exchange and protonation reactions occurred. Greater than 99.8% of hydrogen and 98% of helium ions trapped are lost during a scan cycle predominately through reactions with background nitrogen. The neutralization rate of argon ions varied with water concentration, while increased concentrations of all three gases inflated the oxygen ion signal intensity through charge-exchange. Although such dramatic effects challenge the analytical sensitivity and robustness of QITMS for permanent gas analysis, through proper understanding and control of relevant experimental conditions the QITMS can still function in monitoring applications. (c) 2004 Elsevier B.V. All rights reserved. C1 Univ Florida, Dept Chem, Gainesville, FL 32611 USA. ASRC Aerosp, Kennedy Space Ctr, FL 32899 USA. NASA, Kennedy Space Ctr, FL 32899 USA. San Francisco State Univ, Dept Chem & Biochem, San Francisco, CA 94132 USA. RP Ottens, AK (reprint author), Univ Florida, Dept Neurosci, POB 100244, Gainesville, FL 32610 USA. EM aottens@mbi.ufl.edu; richard.arkin-1@ksc.nasa.gov; timothy.p.griffin@nasa.gov; palmer@sfsu.edu; harrison@chem.ufl.edu RI Ottens, Andrew/K-3352-2012; OI Palmer, Peter/0000-0002-3173-5726 NR 29 TC 5 Z9 5 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD MAY 1 PY 2005 VL 243 IS 1 BP 31 EP 39 DI 10.1016/j.ijms.2004.12.005 PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 919HC UT WOS:000228608000002 ER PT J AU Woodson, SH Green, BE Chung, JJ Grove, DV Parikh, PC Forsythe, JR AF Woodson, SH Green, BE Chung, JJ Grove, DV Parikh, PC Forsythe, JR TI Understanding abrupt wing stall with computational fluid dynamics SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut ID FLOWS AB This paper describes the computational-fluid-dynamics efforts and lessons learned during the four-year Abrupt Wing Stall national research program. The paper details the complex nature of the transonic flows encountered by modern U.S. fighter and attack aircraft during transonic maneuvering conditions. Topics include grid resolution, computational memory and processor requirements, turbulence modeling, steady and unsteady calculations, and Reynolds-averaged Navier-Stokes solutions compared with detached-eddy simulations for this highly complex, viscously dominated, shock-induced, massively separated class of flow. Examples include results obtained for F/A-18C, AV-8B, preproduction F/A-18E, and F-16C aircraft undergoing transonic maneuvering conditions. Various flap settings have been modeled and the computational results compared with extensive wind-tunnel data. The comparisons illustrate the results obtained from both structured and unstructured codes. The utility and accuracy of the various computational solvers is evaluated by qualitative comparisons of surface oil flow and pressure-sensitive-paint results obtained in wind tunnels for some of the models as well as by detailed quantitative pressure coefficient data where experimental results exist. Static lift coefficients are compared between the codes as well as the experimental data for each of the aircraft considered in this study. C1 USN Air Syst Command, Patuxent River, MD 20670 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. USAF Acad, Colorado Springs, CO 80840 USA. RP Woodson, SH (reprint author), USN Air Syst Command, Patuxent River, MD 20670 USA. NR 19 TC 6 Z9 7 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 578 EP 585 DI 10.2514/1.2730 PG 8 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400002 ER PT J AU McMillin, SN Hall, RM Lamar, JE AF McMillin, SN Hall, RM Lamar, JE TI Transonic experimental observations of abrupt wing stall on an F/A-18E model SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB A transonic wind-tunnel test of an 8% F/A-18E model was conducted in the NASA Langley Research Center 16 ft Transonic Tunnel to investigate on-surface flow physics during stall. The technical approach employed focused on correlating static (or time-averaged) and unsteady wind-tunnel test data to the unsteady wing-stall events using force, moment, pressure, and pressure-sensitive-paint measurements. This paper focuses on data obtained on the preproduction configuration of the F/A-18E aircraft at Mach number of 0.90. The flow unsteadiness occurring on the wing as the wing went through the stall process was captured using the time histories of balance and pressure measurements and by calculating the root mean square (rms) for a number of instrument signals. The second step was to gather global perspectives on the pressures influencing the wing-stall process. The abrupt wing stall experienced by the 8% F/A-18E model was observed to be an unsteady event triggered by the rapid advancement of separation, which had migrated forward from the trailing edge, to the leading-edge flap hingeline over a very small increment in angle of attack. The angle of attack at which this stall occurred varied, from run to run, over a 1-deg increment. The abrupt wing stall was observed, using pressure-sensitive paint, to occur simultaneously on both wing panels or asymmetrically. The pressure-sensitive-paint data and wing-root bending-moment data were essential in providing insight to the How structures occurring over the wing and the possible asymmetry of those flow structures. A repeatability analysis conducted on eight runs of static data provided a quick and inexpensive examination of the unsteady aerodynamic characteristics of abrupt wing stall. The results of the repeatability analysis agreed extremely well with data obtained using unsteady measurement techniques. This approach could be used to identify test conditions for more complex unsteady data measurements using special instrumentation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP McMillin, SN (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 4 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 586 EP 599 DI 10.2514/1.3152 PG 14 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400003 ER PT J AU Parikh, P Chung, J AF Parikh, P Chung, J TI Computational study of the abrupt-wing-stall characteristics of F/A-18E and F-16C SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB Steady-state computational-fluid-dynamic (CFD) simulations are used to gain an understanding of the physics behind the abrupt-wing-stall (AWS) phenomenon and to arrive at static figures of merit (FOMs). Navier-Stokes solutions are obtained using the NASA Langley Research Center developed TetrUSS simulation suite, which is based on tetrahedral, unstructured grids. The physics of the AWS phenomenon is understood by comparing CFD simulation results on two aircraft; a preproduction F/A-18E configuration, which exhibits AWS phenomenon under certain geometric and flow conditions, and an F-16C aircraft configuration that does not. The computational results are used to understand the possible causes of AWS by comparing the detailed flowfields between the two configurations under a variety of flow conditions. Based on this approach, a number of static figures of merit are developed to predict AWS. The potential FOMs include the break in the lift and wing-root bending moment vs angle of attack alpha and the rate of change of sectional lift with respect to alpha. A companion paper describes a similar study for the AV-8B Harrier and F/A-18C. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. USN, Air Syst Command, Patuxent River, MD 20670 USA. RP Parikh, P (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 10 TC 3 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 600 EP 605 DI 10.2514/1.2857 PG 6 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400004 ER PT J AU Woodson, SH Green, BE Chun, JJ Grove, DV Parikh, PC Forsythe, JR AF Woodson, SH Green, BE Chun, JJ Grove, DV Parikh, PC Forsythe, JR TI Recommendations for computational-fluid-dynamics procedures for predicting abrupt wing stall SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB This paper summarizes the lessons learned from the computational-fluid-dynamics effort of the joint NASA/Navy/Air Force Abrupt Wing Stall Program, discusses the results, and makes recommendations for approaches to be used in future aircraft programs to identify uncommanded lateral characteristics early in the design phase of an aircraft development program. The discussion also suggests procedures and figures of merit for use in predicting and quantifying rapid and severe wing-stall tendencies and vulnerabilities of the proposed designs. Topics addressed include critical parameters that can be used to identify uncommanded lateral activity in the transonic flow regime and the geometric parameters that were the primary contributors to the adverse lateral activity observed on preproduction F/A-18E/F aircraft. In addition, differences in steady-state and averaged time-accurate computational solutions for the F/A-18E in the abrupt-wing-stall region of interest are analyzed and compared with existing unsteady experimental data to determine the utility and accuracy of the unsteady approach. Lastly, proposed computational figures of merit are critically evaluated as indicators of possible abrupt separation tendencies, and screening procedures for the identification of those tendencies are suggested. C1 USN, Air Syst Command, Patuxent River, MD 20670 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. USAF Acad, Colorado Springs, CO 80840 USA. RP Woodson, SH (reprint author), USN, Air Syst Command, Patuxent River, MD 20670 USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 627 EP 633 DI 10.2514/1.3214 PG 7 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400007 ER PT J AU Cook, SP Kokolios, A Page, A Chambers, J Niewoehner, R Owens, DB Roesch, M AF Cook, SP Kokolios, A Page, A Chambers, J Niewoehner, R Owens, DB Roesch, M TI Integrated approach to assessment of transonic abrupt wing stall for advanced aircraft SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB Abrupt wing stall at transonic flight conditions can result in uncommanded rolling motions that have historically degraded flying qualities, compromised mission performance, and reduced safety of flight for a variety of aircraft. Recently, a U.S. government research program, the Abrupt Wing Stall Program, has advanced the state of the art in detection of abrupt wing stall through computational fluid dynamics, experimental aerodynamics, and flight dynamics. It is therefore essential that these tools be combined into an integrated approach that not only provides for the identification of abrupt wing stall, but also allows for the resulting flight characteristics to be assessed and the risks to the aircraft program be mitigated. The primary means of assessing the flying qualities impacts of transonic abrupt wing stall is through the construction of an aircraft math model that can accurately characterize the dynamic response to abrupt stall. The primary means of mitigating program risks is through the inclusion of free-to-roll wind-tunnel testing in the acquisition plan. Recommendations for assessing transonic abrupt wing stall are presented for the aircraft designer and for the program manager. C1 USN, Air Syst Command, Patuxent River, MD 20670 USA. Ball Corp, Hampton, VA 23669 USA. USN Acad, Annapolis, MD 21402 USA. NASA, Langley Res Ctr, Hampton, VA 23669 USA. Boeing Co, St Louis, MO 63166 USA. RP Cook, SP (reprint author), USN, Air Syst Command, Patuxent River, MD 20670 USA. NR 25 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 646 EP 652 DI 10.2514/1.2834 PG 7 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400010 ER PT J AU Hall, RM Woodson, SH Chambers, JR AF Hall, RM Woodson, SH Chambers, JR TI Accomplishments of the abrupt-wing-stall program SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB The Abrupt-Wing-Stall (AWS) Program has addressed the problem of uncommanded lateral motions, such as wing drop and wing rock, at transonic speeds. The genesis of this program was the experience of the F/A-18E/F program in the late 1990s, when wing drop was discovered in the heart of the maneuver envelope for the preproduction aircraft. Although the F/A-18E/F problem was subsequently corrected by a leading-edge flap scheduling change and the addition of a porous door to the wing fold fairing, the AWS program was initiated as a national response to the lack of technology readiness at the time of the F/A-18E/F development program. The AWS program objectives were to define causal factors for the F/A-18E/F experience, to gain insights into the How physics associated with wing drop, and to develop methods and analytical tools so that future programs could identify this type of problem before going to flight test. The major goals of the AWS Program, the status of the technology before the program began, the program objectives, the accomplishments, and the impacts are reviewed. Lessons learned are presented for the benefit of programs that must assess whether a future vehicle will have uncommanded lateral motions before going to flight test. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. USN, Air Syst Command, Patuxent River, MD 20670 USA. Ball Aerosp, Fairborn, OH 45324 USA. RP Hall, RM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 22 TC 7 Z9 7 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 653 EP 660 DI 10.2514/1.3631 PG 8 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400011 ER PT J AU Bhargava, C Loth, E Potapczuk, M AF Bhargava, C Loth, E Potapczuk, M TI Simulating the aerodynamics of the NASA John HG. Glenn icing research tunnel SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB The objective of this study is to develop and employ a numerical simulation strategy for predicting the airflow front the spray bars to the test section of the NASA John H. Glenn Icing Research Tunnel (IRT). In particular, predictions of the mean velocity and turbulence distributions were desired throughout this flow domain to later investigate droplet dispersion. Computational airflow results were produced using the WIND code (developed by NPARC) with a second-order accurate finite difference scheme and the shear stress transport k-Omega urbulence model. The inflow conditions for the flow domain were derived from the IRT measurements just upstream of the spray bars, which reflected the contributions to turbulence from the upstream heat exchanger wake. It was found that inclusion of the spray bar wakes and the air jets (of the spray nozzles) were required to describe the wind-tunnel turbulence distribution. Because it was impractical to simultaneously resolve the overall flow domain (60 ft long), along with the detailed flow around the 10 spray bars and the flow within a hundred airjets (issuing from 1/8-in. nozzle diameters), these features were simulated individually and then algebraically combined together to give an approximate solution. The results of the spray bar wake combined with the heat exchanger How yielded good prediction of test section mean velocity and turbulence for the jets-off condition. Inclusion of all of the individual air jets also yielded reasonable resulting predictions of mean velocity and turbulence in the test section. C1 Univ Illinois, Urbana, IL 61801 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bhargava, C (reprint author), Univ Illinois, Urbana, IL 61801 USA. EM e-loth@uiuc.edu RI Loth, Eric/C-5805-2008 NR 10 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 2005 VL 42 IS 3 BP 671 EP 684 DI 10.2514/1.1966 PG 14 WC Engineering, Aerospace SC Engineering GA 934GH UT WOS:000229694400014 ER PT J AU Noel, V Sassen, K AF Noel, V Sassen, K TI Study of planar ice crystal orientations in ice clouds from scanning polarization lidar observations SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CIRRUS CLOUDS; DEPOLARIZATION TECHNIQUE; MICROPHYSICAL PROPERTIES; RADIATIVE PROPERTIES; BACKSCATTER; CLIMATOLOGY; FACILITY; PLATES AB This paper presents a study of the orientation of ice crystals in cirrus and midlevel clouds, based on the analysis of several cases of scanning polarization lidar observations. The maximum angle that crystals deviate from the horizontal plane is inferred at consecutive altitude levels by fitting angle-dependent measurements of the linear depolarization ratio and backscattered intensities to a theoretical model with a Gaussian distribution of tilt angles. The average deviation angle is linked to the angular variation of backscatter. A rare observation of so-called Parry-oriented columns is also given to highlight the different backscattering behavior with lidar angle. For planar crystals, two orientation modes are found that depend on cloud temperature. High-level cold (less than or similar to-30 degrees C) clouds show a maximum deviation angle of similar to 1.0 degrees, whereas for warmer (greater than or similar to-20 degrees C) midlevel clouds this angle averages similar to 2.0 degrees. This difference is caused by variations in particle shape and fall attitude that depend on temperature, likely involving a transition from simple plates to more widely fluttering dendrites at the warmer temperatures. Polarization lidar scans are clearly uniquely suited for the study of ice crystal orientations in clouds. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Analyt Serv & Mat, Hampton, VA USA. Univ Alaska, Inst Geophys, Fairbanks, AK USA. RP Noel, V (reprint author), NASA, Langley Res Ctr, Mail Stop 435, Hampton, VA 23681 USA. EM v.r.noel@larc.nasa.gov RI Noel, Vincent/C-3702-2013 OI Noel, Vincent/0000-0001-9494-0340 NR 30 TC 47 Z9 52 U1 4 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 2005 VL 44 IS 5 BP 653 EP 664 DI 10.1175/JAM2223.1 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 938KX UT WOS:000230003400007 ER PT J AU Gebremichael, M Krajewski, WF Morrissey, ML Huffman, GJ Adler, RF AF Gebremichael, M Krajewski, WF Morrissey, ML Huffman, GJ Adler, RF TI A detailed evaluation of GPCP 1 degrees daily rainfall estimates over the Mississippi river basin SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID GLOBAL PRECIPITATION; SAMPLING ERROR; SATELLITE; RADAR; VALIDATION; MODEL; UNCERTAINTY; VARIABILITY; SIMULATION; PRODUCTS AB This study provides an intensive evaluation of the Global Precipitation Climatology Project (GPCP) 1 degrees daily (1DD) rainfall products over the Mississippi River basin, which covers 435 1 degrees latitude x 1 degrees longitude grids for the period of January 1997-December 2000 using radar-based precipitation estimates. The authors' evaluation criteria include unconditional continuous, conditional (quasi) continuous, and categorical statistics, and their analyses cover annual and seasonal time periods. The authors present spatial maps that reflect the results for the 1 degrees grids and a summary of the results for three selected regions. They also develop a statistical framework that partitions the GPCP-radar difference statistics into GPCP error and radar error statistics. They further partition the GPCP error statistics into sampling error and retrieval error statistics and estimate the sampling error statistics using a data-based resampling experiment. Highlights of the results include the following: 1) the GPCP 1DD product captures the spatial and temporal variability of rainfall to a high degree, with more than 80% of the variance explained, 2) the GPCP 1DD product proficiently detects rainy days at a large range of rainfall thresholds, and 3) in comparison with radar-based estimates the GPCP 1DD product overestimates rainfall. C1 Univ Iowa, IIHR Hydrosci & Engn, Iowa City, IA 52242 USA. Univ Oklahoma, Environm Verificat & Anal Ctr, Norman, OK USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Appl Inc, Greenbelt, MD 20771 USA. RP Krajewski, WF (reprint author), Univ Iowa, IIHR Hydrosci & Engn, Iowa City, IA 52242 USA. EM witold-krajewski@uiowa.edu RI Gebremichael, Mekonnen/B-3584-2009; Huffman, George/F-4494-2014 OI Huffman, George/0000-0003-3858-8308 NR 40 TC 32 Z9 35 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 2005 VL 44 IS 5 BP 665 EP 681 DI 10.1175/JAM2233.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 938KX UT WOS:000230003400008 ER PT J AU Tokay, A Bashor, PG Wolff, KR AF Tokay, A Bashor, PG Wolff, KR TI Error characteristics of rainfall measurements by collocated Joss-Waldvogel disdrometers SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SIZE DISTRIBUTION MEASUREMENTS; DOPPLER RADAR; RAINDROP SPECTRA; REFLECTIVITY; CALIBRATION; VELOCITY; GAUGE AB Error characteristics of rainfall measurements were studied using six collocated Joss-Waldvogel (JW) disdrometers that are located at NASA's Wallops Flight Facility. The six disdrometer means of rain rate R, reflectivity Z, and differential reflectivity ZDR, for a given minute were considered, as a reference. The maximum deviations of R, Z, and ZDR from the mean in a rain event were 0.6 mm h-1, 1.3 dB, and 0.05 dB, respectively. Rainfall statistics were then examined between disdrometer pairs. The root-mean-square (rms) difference of R, Z, and ZDR between paired disdrometers in a rain event were as high as 3.2 mm h(-1), 3.7 dB, and 0.3 dB, respectively. The rms difference of R and ZDR were even higher when the disdrometer observations were stratified based on reflectivity intervals. The differences in disdrometer rainfall measurements have a potential impact when the disdrometers are considered as calibration tools for vertically pointing and scanning radars. The differences between the disdrometer measurements also result in differences in coefficients and exponents of the derived relations between radar parameters and rain rate. Among the four different relations between radar parameters and rain rate, the absolute difference in rain rate &VERBAR;&UDelta; R&VERBAR; from two different JW disdrometers was highest in R(ZH, ZDR) and lowest in R(KDP, ZDR). The other two relations were R(Z) and R(KDP). The &VERBAR;&UDelta; R&VERBAR; increases with increasing horizontally polarized reflectivity ZH, and differential specific phase KDP in both single- and dual-parameter rainfall estimators, while the &VERBAR; AR&VERBAR; increases with decreasing ZDR in dual-parameter rainfall estimators. Several sources of JW disdrometer malfunctions were also presented. The hardware problems were the leading cause for the malfunction of the JW disdrometers, as identified by the manufacturer. A single JW disdrometer could have inherent measurement errors that can only be identified in the presence of collocated (preferably two) rain-measuring instruments. C1 NASA, Goddard Space Flight Ctr, Sci Syst Appl Inc, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Wallops Flight Facil, Comp Sci Corp, Wallops Isl, VA 23337 USA. RP Tokay, A (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst Appl Inc, Code 912-1, Greenbelt, MD 20771 USA. EM tokay@radar.gsfc.nasa.gov NR 24 TC 42 Z9 42 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 2005 VL 22 IS 5 BP 513 EP 527 DI 10.1175/JTECH1734.1 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 932FX UT WOS:000229540700002 ER PT J AU Pfister, G Gille, JC Ziskin, D Francis, G Edwards, DP Deeter, MN AF Pfister, G Gille, JC Ziskin, D Francis, G Edwards, DP Deeter, MN TI Effects of a spectral surface reflectance on measurements of backscattered solar radiation: Application to the MOPITT methane retrieval SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CARBON-MONOXIDE; INSTRUMENT; POLLUTION; CO; CH4 AB The amount of solar radiation emerging from the top of the atmosphere is strongly influenced by the reflectance of the underlying surface. For this reason, some information about the magnitude and the spectral variability of the surface reflectance typically has to be included in the retrieval of atmospheric parameters from reflected solar radiation measurements. Sufficient information about the surface reflectance properties is rarely available, and the integration of this effect in the retrieval might turn out to be a challenge, especially for broadband instruments. In this paper the focus is on the Measurements of Pollution in the Troposphere (MOPITT) remote sensing instrument. Theoretical studies are performed to investigate how a spectrally varying surface reflectance might impact the retrieval of the total column amount of methane from MOPITT radiance measurements, and the current findings are compared to observed biases. However, the findings present herein might be valuable and applicable for other remote sensing instruments that are sensitive to the amount of solar radiation reflected from the earth's surface. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Graz Univ, Inst Geophys Astrophys & Meteorol, Graz, Austria. Jet Propuls Lab, Div Earth & Space Sci, Pasadena, CA USA. RP Pfister, G (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM pfister@ucar.edu RI Pfister, Gabriele/A-9349-2008; Deeter, Merritt/O-6078-2016 OI Deeter, Merritt/0000-0002-3555-0518 NR 16 TC 6 Z9 7 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 2005 VL 22 IS 5 BP 566 EP 574 DI 10.1175/JTECH1721.1 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 932FX UT WOS:000229540700006 ER PT J AU Geser, A Hofbauer, D Waldmann, J AF Geser, Alfons Hofbauer, Dieter Waldmann, Johannes TI Termination proofs for string rewriting systems via inverse match-bounds SO JOURNAL OF AUTOMATED REASONING LA English DT Article DE string rewriting systems; semi-Thue systems; termination; normalization; reachability; context-free languages; regular languages; match-bounded; inhibitor AB Annotating a letter by a number, one can record information about its history during a rewrite derivation. In each rewrite step, numbers in the reduct are updated depending on the redex numbering. A string rewriting system is called match-bounded if there is a global upper bound to these numbers. Match-boundedness is known to be a strong sufficient criterion for both termination and preservation of regular languages. We show that the string rewriting systems whose inverse (left and right hand sides exchanged) is match-bounded, also have exceptional properties, but slightly different ones. Inverse match-bounded systems need not terminate; they effectively preserve context-free languages; their sets of normalizable strings and their sets of immortal strings are effectively regular. These languages can be used to decide the normalization, the uniform normalization, the termination and the uniform termination problem for inverse match-bounded systems. We also prove that the termination problem is decidable in linear time, and that a certain strong reachability problem is decidable, thereby solving two open problems of McNaughton's. Like match-bounds, inverse match-bounds entail linear derivational complexity on the set of terminating strings. C1 Hsch Tech Wirtschaft & Kultur FH Leipzig, Fachbereich EIT, D-04251 Leipzig, Germany. Hsch Tech Wirtschaft & Kultur FH Leipzig, Fachbereich IMN, D-04251 Leipzig, Germany. NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23665 USA. RP Geser, A (reprint author), Hsch Tech Wirtschaft & Kultur FH Leipzig, Fachbereich EIT, Postfach 30 11 66, D-04251 Leipzig, Germany. EM geser@fbeit.htwk-leipzig.de; dieter@theory.informatik.uni-kassel.de; waldmann@imn.htwk-leipzig.de NR 23 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0168-7433 J9 J AUTOM REASONING JI J. Autom. Reasoning PD MAY PY 2005 VL 34 IS 4 BP 365 EP 385 DI 10.1007/s10817-005-9024-8 PG 21 WC Computer Science, Artificial Intelligence SC Computer Science GA 064KQ UT WOS:000239088700003 ER PT J AU Hugler, M Wirsen, CO Fuchs, G Taylor, CD Sievert, SM AF Hugler, M Wirsen, CO Fuchs, G Taylor, CD Sievert, SM TI Evidence for autotrophic CO2 fixation via the reductive tricarboxylic acid cycle by members of the epsilon subdivision of proteobacteria SO JOURNAL OF BACTERIOLOGY LA English DT Article ID GREEN-SULFUR BACTERIUM; ATP-CITRATE LYASE; ARCHAEBACTERIUM THERMOPROTEUS-NEUTROPHILUS; HYDROGENOBACTER-THERMOPHILUS TK-6; MONOXIDE DEHYDROGENASE PATHWAY; HYDROTHERMAL VENT POLYCHAETE; EAST PACIFIC RISE; SP-NOV.; 3-HYDROXYPROPIONATE CYCLE; PHYLOGENETIC DIVERSITY AB Based on 16S rRNA gene surveys, bacteria of the E subdivision of proteobacteria have been identified to be important members of microbial communities in a variety of environments, and quite a few have been demonstrated to grow autotrophically. However, no information exists on what pathway of autotrophic carbon fixation these bacteria might use. In this study, Thiomicrospira denitrificans and Candidatus Arcobacter sulfidicus, two chemolithoautotrophic sulfur oxidizers of the E. subdivision of proteobacteria, were examined for activities of the key enzymes of the known autotrophic CO2 fixation pathways. Both organisms contained activities of the key enzymes of the reductive tricarboxylic acid cycle, ATP citrate lyase, 2-oxoglutarate: ferredoxin oxidoreductase, and pyruvate:ferredoxin oxidoreductase. Furthermore, no activities of key enzymes of other CO2 fixation pathways, such as the Calvin cycle, the reductive acetyl coenzyme A pathway, and the 3-hydroxypropionate cycle, could be detected. In addition to the key enzymes, the activities of the other enzymes involved in the reductive tricarboxylic acid cycle could be measured. Sections of the genes encoding the alpha- and beta-subunits of ATP citrate lyase could be amplified from both organisms. These findings represent the first direct evidence for the operation of the reductive tricarboxylic acid cycle for autotrophic CO2 fixation in epsilon-proteobacteria. Since epsilon-proteobacteria closely related to these two organisms are important in many habitats, such as hydrothermal vents, oxic-sulfidic interfaces, or oillfields, these results suggest that autotrophic CO2 fixation via the reductive tricarboxyllic acid cycle might be more important than previously considered. C1 Woods Hole Oceanog Inst, Dept Biol, Woods Hole, MA 02543 USA. Univ Freiburg, Inst Biol 2, D-79104 Freiburg, Germany. NASA, Astrobiol Inst, Marine Biol Lab, Woods Hole, MA 02543 USA. RP Sievert, SM (reprint author), Woods Hole Oceanog Inst, Dept Biol, Mail Stop 33, Woods Hole, MA 02543 USA. EM ssievert@whoi.edu NR 60 TC 97 Z9 100 U1 1 U2 25 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD MAY PY 2005 VL 187 IS 9 BP 3020 EP 3027 DI 10.1128/JB.187.9.3020-3027.2005 PG 8 WC Microbiology SC Microbiology GA 919QX UT WOS:000228633800011 PM 15838028 ER PT J AU Lambert, JL Pelletier, CC Borchert, M AF Lambert, JL Pelletier, CC Borchert, M TI Glucose determination in human aqueous humor with Raman spectroscopy SO JOURNAL OF BIOMEDICAL OPTICS LA English DT Article DE glucose; ocular; Raman spectroscopy; diabetes; non-invasive; aqueous humor; optical toxicity; partial least squares ID BLOOD-GLUCOSE; EYE; TECHNOLOGIES; ABSORPTION; RADIATION; EXPOSURE; SPECTRA; TIME AB It has been suggested that spectroscopic analysis of the aqueous humor of the eye could be used to indirectly predict blood glucose levels in diabetics noninvasively. We have been investigating this potential using Raman spectroscopy in combination with partial least squares (PLS) analysis. We have determined that glucose at clinically relevant concentrations can be accurately predicted in human aqueous humor in vitro using a PLS model based on artificial aqueous humor. We have further determined that with proper instrument design, the light energy necessary to achieve clinically acceptable prediction of glucose does not damage the retinas of rabbits and can be delivered at powers below internationally acceptable safety limits. Herein we summarize our current results and address our strategies to improve instrument design. (c) 2005 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Div Ophthalmol, Childrens Hosp Los Angeles, Los Angeles, CA USA. Keck Sch Med, Dept Ophthalmol, Los Angeles, CA USA. RP Lambert, JL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 300-123, Pasadena, CA 91109 USA. EM James.L.Lambert@jpl.nasa.gov NR 36 TC 33 Z9 34 U1 1 U2 15 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 1083-3668 J9 J BIOMED OPT JI J. Biomed. Opt. PD MAY-JUN PY 2005 VL 10 IS 3 AR 031110 DI 10.1117/1.1914843 PG 8 WC Biochemical Research Methods; Optics; Radiology, Nuclear Medicine & Medical Imaging SC Biochemistry & Molecular Biology; Optics; Radiology, Nuclear Medicine & Medical Imaging GA 009QN UT WOS:000235127400011 PM 16229635 ER PT J AU Dong, XQ Minnis, P Xi, BK AF Dong, XQ Minnis, P Xi, BK TI A climatology of midlatitude continental clouds from the ARM SGP Central Facility: Part I: Low-level cloud macrophysical, microphysical, and radiative properties SO JOURNAL OF CLIMATE LA English DT Article ID GROUND-BASED MEASUREMENTS; LIQUID WATER PATH; SOUTHERN GREAT-PLAINS; ATMOSPHERIC RADIATION; BOUNDARY-LAYER; STRATIFORM CLOUDS; MEASUREMENT PROGRAM; FEEDBACK PROCESSES; STRATUS; SURFACE AB A record of single-layer and overcast low cloud (stratus) properties has been generated using approximately 4000 h of data collected from January 1997 to December 2002 at the Atmospheric Radiation Measurement (ARM) Southern Great Plains Central Facility (SCF). The cloud properties include liquid-phase and liquid-dominant mixed-phase low cloud macrophysical, microphysical, and radiative properties including cloud-base and -top heights and temperatures, and cloud physical thickness derived from a ground-based radar and lidar pair, and rawinsonde sounding; cloud liquid water path (LWP) and content (LWC), and cloud-droplet effective radius (r(e)) and number concentration (N) derived from the macrophysical properties and radiometer data; and cloud optical depth (T), effective solar transmission (gamma), and cloud/top-of-atmosphere albedos (R-cldy/R-TOA) derived from Eppley precision spectral pyranometer measurements. The cloud properties were analyzed in terms of their seasonal, monthly, and hourly variations. In general, more stratus clouds occur during winter and spring than in summer. Cloud-layer altitudes and physical thicknesses were higher and greater in summer than in winter with averaged physical thicknesses of 0.85 and 0.73 km for day and night, respectively. The seasonal variations of LWP, LWC, N, tau, R-cdly, and R-TOA basically follow the same pattern with maxima and minima during winter and summer, respectively. There is no significant variation in mean re, however, despite a summertime peak in aerosol loading. Although a considerable degree of variability exists, the 6-yr average values of LWP, LWC, r(e), N, tau, gamma, R-cdly, and RTOA are 151 gm(-2) (138), 0.245 gm(-3) (0.268), 8.7 mu m (8.5), 213 cm(-3) (238), 26.8 (24.8), 0.331, 0.672, and 0.563 for daytime (nighttime). A new conceptual model of midlatitude continental low clouds at the ARM SGP site has been developed from this study. The low stratus cloud amount monotonically increases from midnight to early morning (0930 LT), and remains large until around local noon, then declines until 1930 LT when it levels off for the remainder of the night. In the morning, the stratus cloud layer is low, warm, and thick with less LWC, while in the afternoon it is high, cold, and thin with more LWC. Future parts of this series will consider other cloud types and cloud radiative forcing at the ARM SCF. C1 Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Dong, XQ (reprint author), Univ N Dakota, Dept Atmospher Sci, 4149 Campus Rd,Box 9006, Grand Forks, ND 58202 USA. EM dong@aero.und.edu RI Minnis, Patrick/G-1902-2010; OI Minnis, Patrick/0000-0002-4733-6148; Dong, Xiquan/0000-0002-3359-6117 NR 39 TC 42 Z9 43 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY 1 PY 2005 VL 18 IS 9 BP 1391 EP 1410 DI 10.1175/JCLI3342.1 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 928QV UT WOS:000229287700007 ER PT J AU Hill, CJ Yang, RQ AF Hill, CJ Yang, RQ TI MBE growth optimization of Sb-based interband cascade lasers SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 13th International Conference on Molecular Beam Epitaxy (MBE XII) CY AUG 22-27, 2004 CL Edinburgh, SCOTLAND DE molecular beam epitaxy; laser diodes; infrared devices ID ROOM-TEMPERATURE; MU-M AB Antimonide- based type-II interband cascade diode lasers are rapidly becoming a viable technology for both in situ sensing and high-power laser applications in the 3-5 μ m range. Recently, this type of electrically pumped diode laser has been shown at the Jet Propulsion Laboratory to operate in continuous wave mode at heat-sink temperatures as high as 212 K near 3.3 μ m and 165 K at 5.4 μ m. In pulsed operation, lasers with emission wavelengths near 3.3 μ m can be operated at temperatures up to the 325 K limit of the measurement cryostat. Careful optimization of the growth conditions of the laser cascade and optical cladding regions must take place in order to achieve the high degree of crystalline quality necessary for optimum device performance. Published by Elsevier B.V. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hill, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 302-306a, Pasadena, CA 91109 USA. EM cory.j.hill@jpl.nasa.gov NR 9 TC 24 Z9 27 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY 1 PY 2005 VL 278 IS 1-4 BP 167 EP 172 DI 10.1016/j.jcrysgro.2004.12.089 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 923NJ UT WOS:000228916300029 ER PT J AU Schobeiri, MT Ozturk, B Ashpis, DE AF Schobeiri, MT Ozturk, B Ashpis, DE TI On the physics of flow separation along a low pressure turbine blade under unsteady flow conditions SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID BOUNDARY-LAYER-TRANSITION; WAKES AB The present study, which is the first of a series of investigations dealing with specific issue of low pressure turbine (LPT) boundary layer aerodynamics, is aimed at providing detailed unsteady boundary flow information to understand the underlying physics of the inception, onset, and extent of the separation zone. A detailed experimental study on the behavior of the separation zone on the suction surface of a highly loaded LPT-blade under periodic unsteady wake flow is presented. Experimental investigations were performed at Texas A&M Turbomachinery Performance and Flow Research Laboratory. using a large-scale unsteady turbine cascade research facility with an integrated wake generator and test section unit. To account for a high flow deflection of LPT-cascades at design and off-design operating points, the entire wake generator and test section unit including the traversing system is designed to allow a precise angle adjustment of the cascade relative to the incoming flow. This is done by a hydraulic platform, which simultaneously lifts and rotates the wake generator and test section unit. The unit is then attached to the tunnel exit nozzle with an angular accuracy of better than 0.05-, which is measured electronically. Utilizing a Reynolds number of 110,000 based on the blade suction surface length and the exit velocity, one steady and two different unsteady inlet flow conditions with the corresponding passing frequencies, wake velocities and turbulence intensities are investigated using hot-wire anemometry. In addition to the unsteady boundary layer measurements, blade surface pressure measurements were performed at Re=50,000, 75,000, 100,000, and 125,000 at one steady and two periodic unsteady inlet flow conditions. Detailed unsteady boundary layer measurement identifies the onset and extent of the separation zone as well as its behavior under unsteady wake flow. The results presented in ensemble -averaged and contour plot forms contribute to understanding the physics of the separation phenomenon under periodic unsteady wake flow. Several physical mechanisms are discussed. C1 Texas A&M Univ, Turbomachinery Performance & Flow Res Lab, College Stn, TX 77843 USA. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Schobeiri, MT (reprint author), Texas A&M Univ, Turbomachinery Performance & Flow Res Lab, College Stn, TX 77843 USA. NR 23 TC 14 Z9 14 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD MAY PY 2005 VL 127 IS 3 BP 503 EP 513 DI 10.1115/1.1905646 PG 11 WC Engineering, Mechanical SC Engineering GA 940FL UT WOS:000230129000010 ER PT J AU Markley, FL Andrews, SF O'Donnell, JR Ward, DK AF Markley, FL Andrews, SF O'Donnell, JR Ward, DK TI Attitude control system of the Wilkinson Microwave Anisotropy Probe SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation, and Control Conference CY AUG 05-08, 2002 CL MONTEREY, CA SP Amer Inst Aeronaut & Astronaut ID DESIGN; MAPS; MISSION AB The Wilkinson Microwave Anisotropy Probe mission produces a map of the cosmic microwave background radiation over the entire celestial sphere by executing a fast spin and a slow precession of its spin axis about the sun line to obtain a highly interconnected set of measurements. The attitude control system implements this spin-scan observing strategy while minimizing thermal and magnetic fluctuations, especially those synchronous with the spin period. The spacecraft attitude is sensed and controlled using an inertial reference unit, 2 star trackers, a dual-head digital sun sensor, 12 coarse sun sensors, 3 reaction wheel assemblies, and a propulsion system. Sufficient attitude knowledge is provided to yield instrument pointing to a standard deviation (1σ) of 1.3 arc-min per axis. The attitude control system also maintains the spacecraft attitude during orbit maneuvers, controls the spacecraft angular momentum, and provides for safety in the event of an anomaly. An overview of the design of the attitude control system to carry out this mission is presented, as well as some early flight experience. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Space Syst Mission Branch, Greenbelt, MD 20771 USA. RP Markley, FL (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. NR 30 TC 9 Z9 9 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2005 VL 28 IS 3 BP 385 EP 397 DI 10.2514/1.6627 PG 13 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 925DG UT WOS:000229031100001 ER PT J AU Wie, B Roithmayr, CM AF Wie, B Roithmayr, CM TI Attitude and orbit control of a very large geostationary solar power satellite SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SIMULTANEOUS ECCENTRICITY; SPACE STATION; LONGITUDE; SYSTEM AB Design of an attitude- and orbit-control system is presented for a 3.2 x 3.2 km geostationary solar-array platform with an area-to-mass ratio of 0.4 m(2)/kg. The proposed control-system architecture utilizes electric thrusters for integrated attitude and orbit eccentricity control by counteracting, simultaneously, attitude-disturbance torques and a large orbital perturbing force. Significant control-structure interaction, possible for such a very large flexible structure, is avoided by employing a low-bandwidth attitude-control system. However, a concept of persistent-disturbance accommodating control is utilized to provide precision attitude control in the presence of dynamic modeling uncertainties and persistent external disturbances. C1 Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Hampton, VA 23681 USA. RP Wie, B (reprint author), Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. EM bong.wie@asu.edu; c.m.roithmayr@larc.nasa.gov NR 35 TC 7 Z9 13 U1 1 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2005 VL 28 IS 3 BP 439 EP 451 DI 10.2514/1.6813 PG 13 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 925DG UT WOS:000229031100006 ER PT J AU Lu, B Wu, F Kim, SW AF Lu, B Wu, F Kim, SW TI Linear parameter-varying antiwindup compensation for enhanced flight control performance SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance Navigation and Control Conference CY AUG 11-14, 2003 CL Austin, TX SP Amer Inst Aeronaut & Astronaut ID SYSTEMS; SATURATION AB Actuator saturation is one of the major issues of flight control in the high-angle-of-attack region. A saturation control scheme for linear parameter-varying (LPV) systems from an antiwindup control perspective is presented. The proposed control approach is advantageous from the implementation standpoint because it can be thought of as an augmented control algorithm to the existing control system. Moreover, the synthesis condition for an antiwindup compensator is formulated as a linear matrix inequality optimization problem and can be solved efficiently. We have applied the LPV antiwindup controller to an F-16 longitudinal autopilot control system design and compared it with the thrust vectoring control scheme. The nonlinear simulations show that an LPV antiwindup controller improves flight quality and offers advantages over thrust vectoring in a high-angle-of-attack region. C1 N Carolina State Univ, Dept Aerosp Engn & Mech, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23681 USA. RP Lu, B (reprint author), N Carolina State Univ, Dept Aerosp Engn & Mech, Raleigh, NC 27695 USA. EM fwu@eos.ncsu.edu RI KIM, SUNGWAN/E-4165-2012; Wu, Fen/H-5814-2012 OI Wu, Fen/0000-0001-8917-4557 NR 27 TC 26 Z9 27 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 2005 VL 28 IS 3 BP 494 EP 505 DI 10.2514/1.4952 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 925DG UT WOS:000229031100011 ER PT J AU Stone, RB Tumer, IY Van Wie, M AF Stone, RB Tumer, IY Van Wie, M TI The function-failure design method SO JOURNAL OF MECHANICAL DESIGN LA English DT Article AB To succeed in the product development market today, firms must quickly and accurately satisfy customer needs while designing products that adequately accomplish their desired functions with a minimum number of failures. When failure analysis and prevention are coupled with a product's design from its conception, potentially shorter design times and fewer redesigns are necessary to arrive at a final product design. In this article, we explore the utility of a novel design methodology that allows failure modes and effects analysis (FMEA)-style failure analysis to be conducted during conceptual design. The function-failure design method (FFDM) guides designers towards improved designs by predicting likely failure modes based on intended product functionality. C1 Univ Missouri, Dept Basic Engn, Rolla, MO 65409 USA. NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Stone, RB (reprint author), Univ Missouri, Dept Basic Engn, Rolla, MO 65409 USA. EM rstone@umr.edu; itumer@mail.arc.nasa.gov; vanwie@umr.edu NR 27 TC 85 Z9 86 U1 1 U2 12 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD MAY PY 2005 VL 127 IS 3 BP 397 EP 407 DI 10.1115/1.1862678 PG 11 WC Engineering, Mechanical SC Engineering GA 932LI UT WOS:000229554800006 ER PT J AU Devi, VM Benner, DC Smith, MAH Rinsland, CP Predoi-Cross, A Sharpe, SW Sams, RL Boulet, C Bouanich, JP AF Devi, VM Benner, DC Smith, MAH Rinsland, CP Predoi-Cross, A Sharpe, SW Sams, RL Boulet, C Bouanich, JP TI A multispectrum analysis of the v(2) band of (HCN)-C-12-N-14: Part I. Intensities, broadening, and shift coefficients SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE HCN; infrared spectra; Fourier transform infrared spectroscopy; absolute intensity; broadening and pressure shift coefficients ID DIODE-LASER MEASUREMENTS; ATMOSPHERIC HYDROGEN-CYANIDE; WATER-VAPOR; NU(2) BAND; SPECTROSCOPIC MEASUREMENTS; V(1) BAND; NU-2 BAND; HCN; TEMPERATURE; REGION AB Absolute intensities, self- and air-broadening coefficients, self- and air-induced shift coefficients and their temperature dependences have been determined for lines belonging to the P- and R-branches of the nu(2) band of (HCN)-C-12-N-14 centered near 712 cm(-1). Infrared spectra of HCN in the 14-mu m region were obtained at high resolution (0.002-0.008 cm(-1)) using two different Fourier transform spectrometers (FTS), the McMath-Pierce FTS at the National Solar Observatory on Kitt Peak and the Bruker IFS 120HR FTS at the Pacific Northwest National Laboratory. Spectra were recorded with 99.8% pure HCN as well as lean mixtures of HCN in air at various temperatures ranging between +26 and -60 degrees C. A multispectrum nonlinear least squares technique was used to fit selected intervals of 36 spectra simultaneously to obtain the line positions, intensities, broadening, and shift parameters. The measured line intensities were analyzed to determine the vibrational band intensity and the Herman-Wallis coefficients. The measured self-broadening coefficients vary between 0.2 and 1.2 cm(-1) atm(-1) at 296 K, and the air-broadening coefficients range from 0.08 to 0.14 cm(-1) atm(-1) at 296 K. The temperature dependence exponents of self-broadening range from 1.46 to -0.12 while the corresponding exponents for air broadening vary between 0.58 and 0.86. The present measurements are the first known determination of negative values for the temperature dependence exponents of HCN-broadening coefficients. We were able to support our self-broadening measurements with appropriate theoretical calculations. Our present measurements are compared, where possible, with previous measurements for this and other HCN bands, as well as the parameters that are included in the 2000 and 2004 editions of the high-resolution transmission (HITRAN) database. (c) 2005 Elsevier Inc. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Lethbridge, Dept Phys, Lethbridge, AB T1K 3M4, Canada. Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Paris 11, Photophys Mol Lab, F-91405 Orsay, France. RP Benner, DC (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. EM dcbenn@wm.edu NR 47 TC 13 Z9 13 U1 2 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2005 VL 231 IS 1 BP 66 EP 84 DI 10.1016/j.jms.2004.12.004 PG 19 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 917DF UT WOS:000228435500008 ER PT J AU Bouanich, JP Boulet, C Predoi-Cross, A Sharpe, SW Sams, RL Smith, MAH Rinsland, CP Benner, DC Devi, VM AF Bouanich, JP Boulet, C Predoi-Cross, A Sharpe, SW Sams, RL Smith, MAH Rinsland, CP Benner, DC Devi, VM TI A multispectrum analysis of the v(2) band of (HCN)-C-12-N-14: Part II. Theoretical calculations of self-broadening, self-induced shifts, and their temperature dependences SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE HCN; theoretical broadening and shifts; infrared spectra; FTIR spectroscopy ID DIODE-LASER MEASUREMENTS; OVERTONE BANDS; SPECTRAL LINES; HCN; TRANSITIONS; MOLECULES; REGION; COEFFICIENTS; INTENSITIES; RANGE AB A semiclassical theory based upon the Robert-Bonamy formalism has been developed to explain the experimental measurements of self-broadening, self-induced pressure shift coefficients in the nu(1), nu(2), 2 nu(2) bands of (HCN)-C-12-N-14 and the 2 nu(1) band of (HCN)-C-13-N-14, as well as the temperature dependences of these parameters with special emphasis on the nu(2) band. Our calculations include only electrostatic interactions and neglect the vibrational dependence of the isotropic part of the intermolecular potential, which probably has a weak contribution to the HCN self-shifts for the bands investigated in this study. The agreement between theory and measurements is good in the cases of self-broadening coefficients and their variation with temperature, as well as the self-shift coefficients determined at room temperature. However, the observed temperature dependence of self-shift coefficients in the nu(2) band is different from that derived theoretically. (c) 2004 Elsevier Inc. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. Univ Lethbridge, Dept Phys, Lethbridge, AB T1K 3M4, Canada. Pacific NW Natl Lab, Richland, WA 99352 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. EM m.d.venkataraman@larc.nasa.gov NR 26 TC 9 Z9 9 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2005 VL 231 IS 1 BP 85 EP 95 DI 10.1016/j.jms.2004.12.002 PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 917DF UT WOS:000228435500009 ER PT J AU Kwon, YW Manthena, C Oh, JJ Srivastava, D AF Kwon, YW Manthena, C Oh, JJ Srivastava, D TI Vibrational characteristics of carbon nanotubes as nanomechanical resonators SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE carbon nanotubes; resonator; natural frequency; mode shape; SWCNT; MWCNT; heterogeneous CNT AB Using eigenvalue analysis of mass and stiffness matrices directly computed from atomistic simulations, natural frequencies and mode shapes of various carbon nanotubes are studied. The stiffness matrix was developed from the Tersoff-Brenner potential for carbon-carbon interactions. The computed frequencies of the radial breathing modes of a variety of armchair (n, n) nanotubes agree well with results obtained by others using different techniques. In addition, the study reveals diverse mode shapes such as accordion-like axial modes, lateral bending modes, torsional modes, axial shear modes, and radial breathing modes for a variety of single-wall, multi-wall, and bamboo-type carbon nanotubes. The effects of different constraints on the carbon nanotube ends on the computed frequencies and mode shapes have been investigated for possible applications in vibration sensors or electromechanical resonators. C1 So Illinois Univ, Dept Mech Engn & Energy Proc, Carbondale, IL 62901 USA. USN, Postgrad Sch, Dept Phys, Monterey, CA 93943 USA. NASA, Ames Res Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP So Illinois Univ, Dept Mech Engn & Energy Proc, Carbondale, IL 62901 USA. NR 20 TC 22 Z9 22 U1 1 U2 12 PU AMER SCIENTIFIC PUBLISHERS PI VALENCIA PA 26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA SN 1533-4880 EI 1533-4899 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD MAY PY 2005 VL 5 IS 5 BP 703 EP 712 DI 10.1166/jnn.2005.110 PG 10 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 926JQ UT WOS:000229119900002 PM 16010925 ER PT J AU Mao, A Ng, HT Nguyen, P McNeil, M Meyyappan, M AF Mao, A Ng, HT Nguyen, P McNeil, M Meyyappan, M TI Silicon nanowire synthesis by a vapor-liquid-solid approach SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE silicon nanowires; VLS approach; vertical transistors; nanowire synthesis; catalyzed growth; vertical nanowires ID SEMICONDUCTOR NANOWIRES; GROWTH; DIAMETER AB Synthesis of silicon nanowires is studied by using a vapor-liquid-solid growth technique. Silicon tetrachloride reduction with hydrogen in the gas phase is used with gold serving as catalyst to facilitate growth. Only a narrow set of conditions of SiCl4 concentration and temperature yield straight nanowires. High concentrations and temperatures generally result in particulates, catalyst coverage and deactivation, and coatinglike materials. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Chem Engn, San Jose, CA 95192 USA. RP Meyyappan, M (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. NR 15 TC 9 Z9 9 U1 1 U2 13 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD MAY PY 2005 VL 5 IS 5 BP 831 EP 835 DI 10.1166/jnn.2005.107 PG 5 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 926JQ UT WOS:000229119900025 PM 16010948 ER PT J AU Highstein, SM Rabbitt, RD Holstein, GR Boyle, RD AF Highstein, SM Rabbitt, RD Holstein, GR Boyle, RD TI Determinants of spatial and temporal coding by semicircular canal afferents SO JOURNAL OF NEUROPHYSIOLOGY LA English DT Review ID TURTLE POSTERIOR CRISTA; AUDITORY HAIR-CELLS; PERIPHERAL INNERVATION PATTERNS; TOADFISH OPSANUS-TAU; SQUIRREL-MONKEY; RESPONSE DYNAMICS; VESTIBULAR NERVE; TRANSDUCER ADAPTATION; RESTING DISCHARGE; PHYSIOLOGIC CHARACTERISTICS AB The vestibular semicircular canals are internal sensors that signal the magnitude, direction, and temporal properties of angular head motion. Fluid mechanics within the 3-canal labyrinth code the direction of movement and integrate angular acceleration stimuli over time. Directional coding is accomplished by decomposition of complex angular accelerations into 3 biomechanical components-one component exciting each of the 3 ampullary organs and associated afferent nerve bundles separately. For low-frequency angular motion stimuli, fluid displacement within each canal is proportional to angular acceleration. At higher frequencies, above the lower corner frequency, real-time integration is accomplished by viscous forces arising from the movement of fluid within the slender lumen of each canal. This results in angular velocity sensitive fluid displacements. Reflecting this, a subset of afferent fibers indeed report angular acceleration to the brain for low frequencies of head movement and report angular velocity for higher frequencies. However, a substantial number of afferent fibers also report angular acceleration, or a signal between acceleration and velocity, even at frequencies where the endolymph displacement is known to follow angular head velocity. These non-velocity-sensitive afferent signals cannot be attributed to canal biomechanics alone. The responses of non-velocity-sensitive cells include a mathematical differentiation (first-order or fractional) imparted by hair-cell and/or afferent complexes. This mathematical differentiation from velocity to acceleration cannot be attributed to hair cell ionic currents, but occurs as a result of the dynamics of synaptic transmission between hair cells and their primary afferent fibers. The evidence for this conclusion is reviewed below. C1 Washington Univ, Sch Med, Dept Otolaryngol, St Louis, MO 63110 USA. Univ Utah, Dept Bioengn, Salt Lake City, UT 84112 USA. Mt Sinai Sch Med, Dept Neurol, New York, NY USA. NASA, Ames BioVIS Technol Ctr, Moffett Field, CA USA. Marine Biol Lab, Woods Hole, MA 02543 USA. RP Highstein, SM (reprint author), Washington Univ, Sch Med, Dept Otolaryngol, St Louis, MO 63110 USA. FU NIDCD NIH HHS [R01 DC006685-03, P01 DC001837, R01 DC004928-06, R55 DC-05585, R01 DC004928, R01 DC006685, P01 DC-01837] NR 92 TC 32 Z9 33 U1 1 U2 8 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-3077 EI 1522-1598 J9 J NEUROPHYSIOL JI J. Neurophysiol. PD MAY PY 2005 VL 93 IS 5 BP 2359 EP 2370 DI 10.1152/jn.00533.2004 PG 12 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 918VH UT WOS:000228575200001 PM 15845995 ER PT J AU Li, L Sweet, BT Stone, LS AF Li, L Sweet, BT Stone, LS TI Effect of contrast on the active control of a moving line SO JOURNAL OF NEUROPHYSIOLOGY LA English DT Article ID PURSUIT EYE-MOVEMENTS; VISUAL FEEDBACK-CONTROL; SMOOTH-PURSUIT; REACTION-TIME; SPEED PERCEPTION; MANUAL TRACKING; PERCEIVED SPEED; DIRECTION DISCRIMINATION; SPATIAL-FREQUENCY; MOTION PERCEPTION AB In many passive visual tasks, human perceptual judgments are contrast dependent. To explore whether these contrast dependencies of visual perception also affect closed-loop manual control tasks, we examined visuomotor performance as humans actively controlled a moving luminance-defined line over a range of contrasts. Four subjects were asked to use a joystick to keep a horizontal line centered on a display as its vertical position was perturbed by a sum of sinusoids under two control regimes. The total root mean square (RMS) position error decreased quasi-linearly with increasing log contrast across the tested range ( mean slope across subjects: - 8.0 and - 7.7% per log(2) contrast, for the two control regimes, respectively). Frequency - response ( Bode) plots showed a systematic increase in open-loop gain ( mean slope: 1.44 and 1.30 dB per log(2) contrast, respectively), and decrease in phase lag with increasing contrast, which can be accounted for by a decrease in response time delay ( mean slope: 32 and 40 ms per log(2) contrast, respectively). The performance data are well fit by a Crossover Model proposed by McRuer and Krendel, which allowed us to identify both visual position and motion cues driving performance. This analysis revealed that the position and motion cues used to support manual control under both control regimes appear equally sensitive to changes in stimulus contrast. In conclusion, our data show that active control of a moving visual stimulus is as dependent on contrast as passive perception and suggest that this effect is attributed to a shared contrast sensitivity early in the visual pathway, before any specialization for motion processing. C1 NASA, Ames Res Ctr, Human Informat Proc Res Branch, Moffett Field, CA 94035 USA. San Jose State Univ, San Jose, CA 95192 USA. RP Li, L (reprint author), NASA, Ames Res Ctr, Human Informat Proc Res Branch, MS 262-2, Moffett Field, CA 94035 USA. EM lli@mail.arc.nasa.gov NR 77 TC 11 Z9 11 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-3077 J9 J NEUROPHYSIOL JI J. Neurophysiol. PD MAY PY 2005 VL 93 IS 5 BP 2873 EP 2886 DI 10.1152/jn.00200.2004 PG 14 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 918VH UT WOS:000228575200047 PM 15615838 ER PT J AU Markusic, TE Polzin, KA Choueiri, EY Keidar, M Boyd, ID Lepsetz, N AF Markusic, TE Polzin, KA Choueiri, EY Keidar, M Boyd, ID Lepsetz, N TI Ablative Z-pinch pulsed plasma thruster SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID DISCHARGE; PROPULSION AB The design, performance, and basic features of ablative pulsed plasma thrusters based on the z-pinch configuration are discussed through a series of experiments and numerical simulations. The motivation stems from the promise of the z-pinch configuration for increasing the thrust-to-power ratio and mass utilization efficiency above those of ablative thrusters with a conventional rectangular geometry. The performance of a series of ablative z-pinch pulsed plasma thrusters is characterized using a swinging-gate thrust stand and mass ablation measurements. The performance measurements are complemented by additional experimental diagnostics (current monitoring and high-speed photography) and numerical modeling in order to gain an understanding of the acceleration mechanism and provide direction for future design iterations. Three iterations in the design of the thruster result in thrust-to-power ratios ranging from 12-45 μ N/W, with specific impulse and thrust efficiency values spanning 240-760 s and 2-9%, respectively. Numerical simulations show reasonable quantitative agreement with the experimental data and predict the existence of an optimal thrust chamber aspect ratio, which maximizes the thrust-to-power ratio. C1 Princeton Univ, USAF Palace Knight, Elect Propuls & Plasma Dynam Lab, Dept Aerosp & Mech Engn,Appl Phys Grp, Princeton, NJ 08544 USA. Princeton Univ, Natl Def Sci & Engn, Princeton, NJ 08544 USA. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. RP Markusic, TE (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM choueiri@princeton.edu NR 39 TC 13 Z9 18 U1 1 U2 8 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2005 VL 21 IS 3 BP 392 EP 400 DI 10.2514/1.4362 PG 9 WC Engineering, Aerospace SC Engineering GA 926OO UT WOS:000229132700002 ER PT J AU Emrich, WJ Hawk, CW AF Emrich, WJ Hawk, CW TI Magnetohydrodynamic instabilities in a simple gasdynamic mirror propulsion system SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID GAS-DYNAMIC TRAP; FLUTE INSTABILITY AB The gasdynamic mirror has been proposed as a concept that could form the basis of a highly efficient fusion rocket engine. Gasdynamic mirrors differ from most other mirror-type plasma confinement schemes in that they have much larger aspect ratios and operate at somewhat higher plasma densities. To evaluate whether a gasdynamic mirror could indeed confine plasmas in a stable manner for long periods of time, a small-scale experimental gasdynamic mirror was built and tested. The objective of this experiment was to determine ranges of mirror ratios and plasma densities over which a gasdynamic mirror could maintain stable plasmas. Theoretical analyses indicated that plasma magnetohydrodynamic (MHD) instabilities were likely to occur during subsonic to supersonic flow transitions in the throat region of the gasdynamic mirror. The experimental evidence, based on data derived from langmuir probe measurements, seems to confirm this analysis. The assumption that a gasdynamic mirror using a simple mirror geometry could be used as a propulsion system, therefore, appears questionable. Modifications to the simple mirror concept are presented that could mitigate these MHD instabilities. C1 NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35812 USA. Univ Alabama, Propuls Res Ctr, Huntsville, AL 35899 USA. RP Emrich, WJ (reprint author), NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35812 USA. NR 13 TC 1 Z9 1 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2005 VL 21 IS 3 BP 401 EP 407 DI 10.2514/1.7027 PG 7 WC Engineering, Aerospace SC Engineering GA 926OO UT WOS:000229132700003 ER PT J AU Morris, CI AF Morris, CI TI Numerical modeling of single-pulse gasdynamics and performance of pulse detonation rocket engines SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID IMPULSE; FLOWS; SIMULATIONS; PROPULSION AB Pulse detonation rocket engines (PDREs) offer potential performance improvements over conventional designs but represent a challenging modeling task. A quasi-one-dimensional, finite rate chemistry computational fluid dynamics model for PDREs is described and implemented. Four different PDRE geometries are evaluated in this work: a baseline detonation tube, a detonation tube with a straight extension, and a detonation tube with two types of converging/diverging (CD) nozzles. The effect of extension length and CD nozzle area ratio on the single-pulse gasdynamics and performance of a PDRE is studied over a wide range of blowdown pressure ratios (1-1000). The results indicate that a CD nozzle is generally more effective than a straight extension in improving PDRE performance, particularly at higher pressure ratios. Additionally, the results show that the blowdown process of the CD nozzle systems could be beneficially cut off well before the pressure at the endwall reaches the ambient value. The single-pulse performance results are also compared to some recent experimental measurements as well as a steady-state rocket system using similar modeling assumptions. C1 NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr TD40, Huntsville, AL 35812 USA. RP Morris, CI (reprint author), NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr TD40, Huntsville, AL 35812 USA. NR 46 TC 24 Z9 25 U1 1 U2 5 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 EI 1533-3876 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2005 VL 21 IS 3 BP 527 EP 538 DI 10.2514/1.7875 PG 12 WC Engineering, Aerospace SC Engineering GA 926OO UT WOS:000229132700017 ER PT J AU Perkins, HD Sung, CJ AF Perkins, HD Sung, CJ TI Effects of fuel distribution on detonation tube performance SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID ENGINES; SIMULATIONS AB A pulse detonation engine uses a series of high-frequency intermittent detonation tubes to generate thrust. The process of filling the detonation tube with fuel and air for each cycle may yield nonuniform mixtures. Uniform mixing is commonly assumed when calculating detonation tube thrust performance. Detonation cycles featuring idealized nonuniform H-2-air mixtures were analyzed using a two-dimensional Navier-Stokes computational fluid dynamics code with finite-rate chemistry. Mixture nonuniformities examined included axial equivalence ratio gradients, transverse equivalence ratio gradients, and partially fueled tubes. Three different average test section equivalence ratios were studied: one stoichiometric, one fuel lean, and one fuel rich. All mixtures were detonable throughout the detonation tube. Various mixtures representing the same average test section equivalence ratio were shown to have specific impulses within 1% of each other, indicating that good fuel-air mixing is not a prerequisite for optimal detonation tube performance under the conditions investigated in an H-2-air system. C1 NASA, Glenn Res Ctr Lewis Field, Engine Syst Branch, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. RP Perkins, HD (reprint author), NASA, Glenn Res Ctr Lewis Field, Engine Syst Branch, Cleveland, OH 44135 USA. EM Hugh.D.Perkins@nasa.gov; cjs15@po.cwru.edu NR 28 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2005 VL 21 IS 3 BP 539 EP 545 DI 10.2514/1.2253 PG 7 WC Engineering, Aerospace SC Engineering GA 926OO UT WOS:000229132700018 ER PT J AU Lattime, SB Steinetz, BM Robbie, MG AF Lattime, SB Steinetz, BM Robbie, MG TI Test rig for evaluating active turbine blade tip clearance control concepts SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Improved blade tip sealing in the high-pressure compressor and high-pressure turbine can provide dramatic improvements in specific fuel consumption, time on wing, compressor stall margin, and engine efficiency, as well as increased payload and mission range capabilities of both military and commercial gas-turbine engines. The design of a first-generation mechanically actuated active clearance control system for turbine blade tip clearance management is presented, along with the design of a bench top test rig in which the system is to be evaluated. The active clearance control system utilizes mechanically actuated seal carrier segments and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. The purpose of this active clearance control system is to improve on current case cooling methods. These systems have relatively slow response and do not use clearance measurement, thereby forcing cold-build clearances to set the minimum clearances at extreme operating conditions and not allowing cruise clearances to be minimized due to the possibility of throttle transients. The test rig will simulate proper seal carrier pressure and temperature loading, as well as the magnitudes and rates of blade tip clearance changes of an actual gas-turbine engine. The results of these evaluations will be presented in future works. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Analex Corp, Cleveland, OH 44142 USA. RP Lattime, SB (reprint author), NASA, Glenn Res Ctr, Mail Stop 23-3,2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 16 Z9 19 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 2005 VL 21 IS 3 BP 552 EP 563 DI 10.2514/1.7341 PG 12 WC Engineering, Aerospace SC Engineering GA 926OO UT WOS:000229132700020 ER PT J AU Petkie, DT Helminger, P Winnewisser, BP Winnewisser, M Butler, RAH Jucks, KW De Lucia, FC AF Petkie, DT Helminger, P Winnewisser, BP Winnewisser, M Butler, RAH Jucks, KW De Lucia, FC TI The simulation of infrared bands from the analyses of rotational spectra: the 2v(9)-v(9) and v(5)-v(9) hot bands of HNO3 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE HNO3; hot band intensities; infrared spectra ID NITRIC-ACID; VIBRATIONAL-STATES; LINE-INTENSITIES; NU(9) AB The results of millimeter and submillimeter wave rotational spectroscopy are used to simulate the complex structure of the 2v(9)-v(9) (438 cm(-1)) and v(5)-v(9) (421 cm(-1)) hot bands. The comparison data were obtained with a high-resolution Bruker FTIR. The combination of the quality of these data and the complexity of the spectra of these interacting states represents a stringent test for the simulation. It is shown that the agreement is very good and that this approach is generally advantageous. From this simulation, the ratios of the transition dipole moments for the 2v(9)-v(9) and v(5)-v(9) hot bands with respect to the v(9) fundamental band were found to be 1.38(11) and 0.67(20), respectively. Using these results, the calculated integrated band intensities for the hot bands at 296 K were determined to be S-v(2v(9)-v(9))=1.63 x 10(-18) cm(-1)/(mol cm(-2)) and Sv(v(5)-v(9))=0.36 x 10(-18) cm(-1)/(mol cm(-2)). These results were used to successfully simulate high-resolution stratospheric spectra obtained from a balloon flight of the FIRS-2 spectrometer. The more general problem of the rotation-vibration database and the optimal use of both microwave and infrared data to define it is discussed. It is concluded that it is best if the combination of data takes place at the level of the original spectra. (C) 2004 Elsevier Ltd. All rights reserved. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Wright State Univ, Dept Phys, Dayton, OH 45435 USA. Univ S Alabama, Dept Phys, Mobile, AL 36688 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP De Lucia, FC (reprint author), Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. EM fcd@mps.ohio-state.edu NR 18 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY 1 PY 2005 VL 92 IS 2 BP 129 EP 141 DI 10.1016/j.jqsrt.2004.03.003 PG 13 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 875JM UT WOS:000225416400001 ER PT J AU Rinsland, CP Goldman, A Mahieu, E Zander, R Chiou, LS Hannigan, JW Wood, SW Elkins, JW AF Rinsland, CP Goldman, A Mahieu, E Zander, R Chiou, LS Hannigan, JW Wood, SW Elkins, JW TI Long-term evolution in the tropospheric concentration of chlorofluorocarbon 12 (CCl2F2) derived from high-spectral resolution infrared solar absorption spectra: retrieval and comparison with in situ surface measurements SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE remote sensing; chlorofluorocarbons; troposphere; atmospheric chemistry; pollution; ozone ID SPECTROSCOPIC MEASUREMENTS; HITRAN; OZONE; STRATOSPHERE; DATABASE AB The average tropospheric volume mixing ratios of chlorofluorocarbon 12 (CCl2F2) have been retrieved from high-spectral resolution ground-based infrared solar-absorption spectra recorded from March 1982 to October 2003 with the McMath Fourier transform spectrometer at the US National Solar Observatory facility on Kitt Peak in southern Arizona (31.9degreesN, 111.6degreesW, 2.09 km altitude). The retrievals are based on fits to the unresolved v(8) band Q-branches near 922 cm(-1) using the SFIT2 retrieval algorithm. The annual increase rate was equal to (16.88 +/- 1.37) parts per trillion (10(-12)) by volume at the beginning of the time series, March 1982, or (4.77 +/- 0.04)%, 1 sigma, declining progressively to (2.49 +/- 1.24) parts per trillion, by volume at the end, October 2003, or (0.46 +/- 0.24)%, 1 sigma. Average tropospheric mixing ratios from the solar spectra have been compared with average surface flask and in situ sampling measurements from the Climate Monitoring and Diagnostics Laboratory (CMDL) station at Niwot Ridge, CO, (USA) (40.0degreesN, 105.5degreesW, 3013 m altitude). The average ratio and standard deviation of the monthly means of the retrieved tropospheric mixing ratios relative to the CMDL surface mixing ratios is (1.01 +/- 0.03) for the overlapping time period. Both datasets demonstrate the progressive impact of the Montreal protocol and its strengthening amendments on the trend of CCl2F2, though a tropospheric decrease has yet to be observed. (C) 2004 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23681 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Univ Liege, Inst Astrophys & Geophys, Liege, Belgium. Sci Applicat Int Corp, Hampton, VA USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. Natl Inst Water & Atmospher Res Ltd, Omakau, New Zealand. NOAA, CMDL R, CMDLI, Boulder, CO 80305 USA. RP NASA, Langley Res Ctr, Atmospher Sci Competency, Mail Stop 401A, Hampton, VA 23681 USA. EM curtis.p.rinsland@nasa.gov OI Mahieu, Emmanuel/0000-0002-5251-0286 NR 27 TC 8 Z9 8 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 EI 1879-1352 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY 1 PY 2005 VL 92 IS 2 BP 201 EP 209 DI 10.1016/j.jqsrt.2004.07.022 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 875JM UT WOS:000225416400006 ER PT J AU Hassan, N Thompson, JE Batra, RC Hulcher, AB Song, XL Loos, AC AF Hassan, N Thompson, JE Batra, RC Hulcher, AB Song, XL Loos, AC TI A heat transfer analysis of the fiber placement composite manufacturing process SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE fiber placement; finite element analysis; manufacturing ID THERMOPLASTIC COMPOSITES; THERMAL-ANALYSIS; TAPE PLACEMENT; CONSOLIDATION; RESIN AB A computer code is developed to accurately simulate the three-dimensional heat transfer during the thermoset fiber placement composite manufacturing process. The code is based on the Lagrangian formulation of the problem. Eight-node brick elements are employed, and the 2 x 2 x 2 integration rule is used to numerically evaluate the integrals over an element. The coupled ordinary differential equations obtained by the semidiscrete formulation of the problem are integrated by the unconditionally stable backward difference method. The code is validated by comparing the computed results for several problems with those available in the literature. Composite rings are manufactured by continuously laying a tape over a cylindrical mandrel and the temperature histories at several points are measured with thermocouples. The computed temperature distribution is found to compare well with the test findings. The code can be used to optimize the processing variables. C1 Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Blacksburg, VA 24061 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. So Illinois Univ, Mat Technol Ctr, Carbondale, IL 62901 USA. RP Loos, AC (reprint author), Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. EM aloos@egr.msu.edu OI Hassan, Noha M./0000-0002-5262-0493 NR 22 TC 12 Z9 15 U1 1 U2 8 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PD MAY 1 PY 2005 VL 24 IS 8 BP 869 EP 888 DI 10.1177/0731684405047773 PG 20 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 926LH UT WOS:000229124200007 ER PT J AU Mase, RA AF Mase, RA TI 2001 Mars Odyssey Mission - Introduction SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Mars Odyssey Project, Pasadena, CA 91125 USA. RP Mase, RA (reprint author), CALTECH, Jet Prop Lab, Mars Odyssey Project, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 385 EP 385 DI 10.2514/1.17749 PG 1 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000001 ER PT J AU Mase, RA Antreasian, PG Bell, JL Martin-Mur, TJ Smith, JC AF Mase, RA Antreasian, PG Bell, JL Martin-Mur, TJ Smith, JC TI Mars Odyssey navigation experience SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The 2001 Mars Odyssey Mission has returned an orbiter to Mars to map the planet and search for water. The success of this mission has reestablished confidence in Mars exploration that will pave the way for future orbiters, landers, and rovers. The spacecraft has completed its journey and is now in the science gathering phase of the mission. The orbital mission began in February 2002 and will continue through at least 2006. We present an overview of the navigation performance, with a comparison of the prelaunch requirements and expected performance to the in-flight experience. C1 CALTECH, Jet Prop Lab, Mars Odysey Navigat Team, Pasadena, CA 91109 USA. RP Mase, RA (reprint author), CALTECH, Jet Prop Lab, Mars Odysey Navigat Team, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 6 Z9 6 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 386 EP 393 DI 10.2514/1.15170 PG 8 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000002 ER PT J AU Antreasian, PG Baird, DT Border, JS Burkhart, PD Graat, EJ Jah, MK Mase, RA McElrath, TP Portock, BM AF Antreasian, PG Baird, DT Border, JS Burkhart, PD Graat, EJ Jah, MK Mase, RA McElrath, TP Portock, BM TI 2001 Mars Odyssey orbit determination during interplanetary cruise SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB On 24 October 2001 coordinated universal time, following a seven-month journey to Mars, Odyssey executed a nominal orbit insertion burn to be captured successfully into orbit around Mars. The excellent navigation performance during the interplanetary cruise resulted in arrival conditions over the north pole of Mars well within 1-sigma of the designed values. The achieved altitude above the north pole was less than 1 km away from the 300-km target altitude. Several sources of error made the orbit determination process for Odyssey challenging. The largest of these errors was caused by the periodic autonomous angular momentum desaturation events. Several navigational aids were brought forth to mitigate the error sources and improve the accuracy of Odyssey's interplanetary cruise navigation. The most significant of these included the incorporation of very long baseline interferometry, delta-differential one-way range tracking data into the orbit determination filtering process and the placement of the spacecraft into a low-torque attitude during the final two months of interplanetary cruise. Orbit determination solution consistency was routinely evaluated through a battery of filter strategies and data combinations. The orbit determination processes and results of Mars Odyssey from launch to orbit insertion at Mars are discussed. C1 CALTECH, Jet Prop Lab, Tracking Syst & Applicat Sect, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Mars Odyssey Project, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Antreasian, PG (reprint author), CALTECH, Jet Prop Lab, Tracking Syst & Applicat Sect, Mail Stop 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Jah, Moriba/0000-0003-1109-0374 NR 6 TC 8 Z9 10 U1 1 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 394 EP 405 DI 10.2514/1.15222 PG 12 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000003 ER PT J AU Smith, JC Bell, JL AF Smith, JC Bell, JL TI 2001 Mars Odyssey aerobraking SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The Mars Odyssey spacecraft was inserted into a highly elliptical capture orbit about Mars on 24 October 2001. To establish the required science mapping orbit, the propulsive capabilities of the spacecraft were supplemented by aerobraking. The necessary orbital period reduction was achieved by 332 successive aerobraking drag passes over a 76-day time period. The strategy, implementation, and results of the aerobraking phase of the mission are detailed. Aerobraking subphases, constraints, modeling, maneuver logic, trajectory characteristics, and key decisions are described. Differences between Odyssey and the Mars Global Surveyor aerobraking experiences are included. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Miss & Syst Architecture Sect, Pasadena, CA 91109 USA. RP Smith, JC (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Mail Stop 230-205,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 13 Z9 18 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 406 EP 415 DI 10.2514/1.15213 PG 10 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000004 ER PT J AU Tartabini, PV Munk, MM Powell, RW AF Tartabini, PV Munk, MM Powell, RW TI Development and evaluation of an operational aerobraking strategy for Mars Odyssey SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID GLOBAL SURVEYOR AB The Mars 2001 Odyssey Orbiter successfully completed the aerobraking phase of its mission on 11 January 2002. The support provided by NASA's Langley Research Center to the navigation team at the Jet Propulsion Laboratory, California Institute of Technology, in the planning and operational support of Mars Odyssey aerobraking is discussed. Specifically, the development of a three-degree-of-freedom aerobraking trajectory simulation and its application to both preflight planning activities and operations is described. The importance of running the simulation in a Monte Carlo fashion to capture the effects of mission and atmospheric uncertainties is demonstrated, and the utility of including predictive logic within the simulation that could mimic operational maneuver decision making is shown. A description is also provided of how the simulation was adapted to support flight operations as both a validation and risk reduction tool and as a means of obtaining a statistical basis for maneuver strategy decisions. This latter application was the first use of Monte Carlo trajectory analysis in an aerobraking mission. C1 NASA, Langley Res Ctr, Aerocapture In Space Prop Technol Project Off, Hampton, VA 23681 USA. RP Tartabini, PV (reprint author), NASA, Langley Res Ctr, Aerocapture In Space Prop Technol Project Off, Hampton, VA 23681 USA. NR 14 TC 7 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 423 EP 434 DI 10.2514/1.15175 PG 12 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000006 ER PT J AU Tolson, RH Dwyer, AM Hanna, JL Keating, GM George, BE Escalera, PE Werner, MR AF Tolson, RH Dwyer, AM Hanna, JL Keating, GM George, BE Escalera, PE Werner, MR TI Application of accelerometer data to Mars Odyssey aerobraking and atmospheric modeling SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID GLOBAL SURVEYOR AB Aerobraking was an enabling technology for the Mars Odyssey mission, even though it involved risk due primarily to the variability of the Mars upper atmosphere. To reduce the risk, numerous analyses, based on various data types, were performed during operations. The use of one such data type, measurements from spacecrafts accelerometers, for determining atmospheric density during Odyssey aerobraking operations is reported. Accelerometer data were analyzed in near real time to provide estimates of density at periapsis, maximum density, density scale height, latitudinal gradient, longitudinal wave variations, and location of the polar vortex. Summaries of the aerobraking phase of the mission, the accelerometer data analysis methods and operational procedures, applications to determining thermospheric properties, and several remaining issues on interpretation of the data are discussed. Although acceleration was measured along three orthogonal axes, only data from the component along the axis nominally into the flow were used during operations. For a 1-s count time, the rms noise level, derived from the acceleration, varied from 0.07 to 0.5 mm/s(2), permitting density recovery to between 0.15 and 1.1 kg/km(3), or about 2% of the mean density at periapsis during aerobraking. Preflight estimates of natural variability based on Mars Global Surveyor accelerometer measurements proved reliable in the midlatitudes but overestimated the variability inside the polar vortex. C1 N Carolina State Univ, Dept Mech & Aerosp Engn & Marine Earth & Atmosphe, Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Explorat Syst Engn Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. George Washington Univ, Dept Mech & Aerosp Engn, Newport News, VA 23606 USA. George Washington Univ, Dept Mech & Aerosp Engn, Hampton, VA 23681 USA. RP Tolson, RH (reprint author), N Carolina State Univ, Dept Mech & Aerosp Engn & Marine Earth & Atmosphe, Natl Inst Aerosp, Hampton, VA 23666 USA. NR 16 TC 31 Z9 33 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 435 EP 443 DI 10.2514/1.15173 PG 9 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000007 ER PT J AU Prince, JLH Chavis, ZQ Wilmoth, RG AF Prince, JLH Chavis, ZQ Wilmoth, RG TI Modeling reaction-control-system effects on Mars Odyssey SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB During the Mars 2001 Odyssey aerobraking mission, NASA Langley Research Center performed six-degree-of-freedom simulations to model rotational motion of the spacecraft. The main objective of this study was to assess the reaction-control-system models and their effects on the atmospheric flight of Odyssey. Based on these models, a comparison was made between data derived from flight measurements to simulated rotational motion of the spacecraft during aerobraking at Mars. The differences between the simulation and flight-derived Odyssey data were then used to adjust the model aerodynamic parameters as a result of reaction-control-system firings to achieve a better correlation. C1 NASA, Langley Res Ctr, Vehicle Anal Branch, Hampton, VA 23681 USA. George Washington Univ, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23665 USA. RP Prince, JLH (reprint author), NASA, Langley Res Ctr, Vehicle Anal Branch, MS 365, Hampton, VA 23681 USA. NR 10 TC 3 Z9 5 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 444 EP 449 PG 6 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000008 ER PT J AU Chavis, ZQ Wilmoth, RG AF Chavis, ZQ Wilmoth, RG TI Plume modeling and application to Mars 2001 Odyssey aerobraking SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A modified source flow model was used to calculate the plume flowfield from a Mars Odyssey thruster during aerobraking. The source flow model results compared well with previous detailed computational-fluid-dynamics results for a Mars Global Surveyor thruster. Using an isodensity surface,for the Odyssey plume, direct simulation Monte Carlo simulations were performed to determine the effect the plumes have on the Odyssey aerodynamics. A database was then built to incorporate the plume effects into six-degree-of-freedom simulations over a range of attitudes and densities expected during aerobraking. Six-degree-of-freedom simulations that included the plume effects showed better correlation with flight data than simulations without the plume effects. C1 George Washington Univ, Joint Inst Advancement Flight Sci, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Chavis, ZQ (reprint author), George Washington Univ, Joint Inst Advancement Flight Sci, Hampton, VA 23681 USA. NR 8 TC 1 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 450 EP 456 DI 10.2514/1.15171 PG 7 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000009 ER PT J AU Amundsen, RM Dec, JA George, BE AF Amundsen, RM Dec, JA George, BE TI Aeroheating thermal model correlation for Mars Global Surveyor solar array SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 36th Thermophysics Conference CY JUN 23-26, 2003 CL ORLANDO, FL SP AIAA AB The Mars Global Surveyor (MGS) spacecraft made use of aerobraking to gradually reduce its orbit period from a highly elliptical insertion orbit to its final science orbit. Aerobraking produces a high heat load on the solar arrays, which have a large surface area exposed to the airflow and relatively low mass. To accurately model the complex behavior during aerobraking, the thermal analysis needed to be tightly coupled to the spatially varying, time-dependent aerodynamic heating. Also, the thermal model itself needed to capture accurately the behavior of the solar array and its response to changing heat load conditions. The correlation of the thermal model to flight data allowed a validation of the modeling process, as well as information on what processes dominate the thermal behavior. Correlation in this case primarily involved detailing the thermal sensor nodes, using as-built mass to modify material property estimates, refining solar-cell assembly properties, and adding detail to radiation and heat-flux boundary conditions. This paper describes the methods used to develop finite element thermal models of the MGS solar array and the correlation of the thermal model to flight data from the spacecraft drag passes. Correlation was made to data from four flight thermal sensors over three of the early drag passes. Good correlation of the model was achieved, with a maximum difference between the predicted model maximum and the observed flight maximum temperature of less than 5%. Lessons learned in the correlation of this model assisted in validating a similar model and method used for the Mars Odyssey solar-array aeroheating analysis, which were used during on-orbit operations. C1 NASA, Langley Res Ctr, Struct & Thermal Anal Branch, Hampton, VA 23681 USA. USAF, Test & Operat Div, SMC Detachment, Kirtland AFB, NM 87111 USA. RP Amundsen, RM (reprint author), NASA, Langley Res Ctr, Struct & Thermal Anal Branch, Mail Stop 431, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 457 EP 466 DI 10.2514/1.3501 PG 10 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000010 ER PT J AU Mettler, E Quadrelli, MB AF Mettler, E Quadrelli, MB TI Multibody dynamics modeling of segmented booms of the Mars Express Spacecraft SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AAS/AIAA 13th Space Flight Mechanics Meeting CY FEB 09-13, 2003 CL Ponce, PR SP AAS, Amer Inst Aeronaut & Astronaut AB We provide an independent modeling and dynamic analysis of the antenna segmented booms deployed on the Mars Express Spacecraft. The Mars Express Spacecraft, built by the ESA, was launched in June 2003 and arrived at Mars in December 2003 to begin a four-year study of the planet's atmosphere, surface, and subsurface. The Mars Advanced Radar for Subsurface and Ionospheric Mapping is a key instrument in the search for water on Mars. Our objective was to determine the antenna's dynamic interaction with the spacecraft bus. Numerical simulations of a model of the spacecraft in the perigee phase of its elliptical Mars orbit were performed; with all booms fully deployed and reaction wheels used to both disturb and control the spacecraft attitude. The simulation results verify the antenna system modeling fidelity and provide data on worst-case dynamic interactions between the flexible booms and the spacecraft bus that demonstrates the dynamic compatibility with the spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mettler, E (reprint author), CALTECH, Jet Prop Lab, Mail Stop 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Marco.B.Quadrelli@jpl.nasa.gov NR 6 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 523 EP 529 DI 10.2514/1.5104 PG 7 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000018 ER PT J AU Quadrelli, MB AF Quadrelli, MB TI Nutation time constant determination of on-axis diaphragm tanks on spinner spacecraft SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AAS/AIAA 13th Space Flight Mechanics Meeting CY FEB 09-13, 2003 CL Ponce, PR SP AAS, Amer Inst Aeronaut & Astronaut ID FREE-SURFACE; LIQUID; DAMPER; SLOSH AB The modeling, analysis, and testing done to determine the Deep Space One nutation time constant are described. The significance of this analysis and testing program is that Deep Space One was the first spacecraft flown by the Jet Propulsion Laboratory with a diaphragm tank located on the spin axis. First, modeling considerations are made, and to simulate the behavior of the spacecraft containing the liquid (hydrazine) the dynamics of a rigid body coupled through a universal joint to a pendulum mass representing the liquid slosh has been analyzed. This simulation is done in order to estimate the natation time constant with a pendulum slosh model. Second, the actual spin drop tests are described. These tests also confirm a notation time constant in excess of 1000 s, both in the case of tests done for the xenon tank only and in the case of tests done for the hydrazine tank only. The large value of the notation time constant computed and verified by testing for this system ensured that it remained well above the required values of 150 s at ignition and 50 s at burnout. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quadrelli, MB (reprint author), CALTECH, Jet Prop Lab, Mail Stop 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM marco@grover.jpl.nasa.gov NR 28 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 530 EP 542 DI 10.2514/1.5054 PG 13 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000019 ER PT J AU Schneider, TA Mikellides, IG Jongeward, GA Peterson, T Kerslake, TW Snyder, D Ferguson, D AF Schneider, TA Mikellides, IG Jongeward, GA Peterson, T Kerslake, TW Snyder, D Ferguson, D TI Solar arrays for direct-drive electric propulsion: Arcing at high voltages SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 39th Joint Propulsion Conference CY JUL 20, 2003 CL Huntsville, AL SP AIAA, ASME, SAE, ASEE ID ORBIT AB The results from an experimental investigation to assess arcing during operation of high-voltage solar arrays in a plasma environment are presented. The experiments were part of an effort to develop systems that would allow safe operation of Hall-effect thruster(s) in direct-drive mode. Are discharges are generated when the array is biased negative with respect to the plasma. If sustained for long periods of time between adjacent solar cells, arcs can severely damage a solar array, thus significantly shortening its lifetime. Most often sustained arcs are triggered by plasma produced during short-duration discharge arcs (similar to 20 ms). These "trigger" arcs are sparked between the semiconducting cell and the covering dielectric. Both trigger and sustained (> 1-ms) arcs have been captured during the tests. Current and voltage waveforms associated with the different arc events are presented. The test results have defined operational limits (thresholds) for the various array concepts studied that minimize the likelihood of damage from sustained arcs. Experimental trends regarding the effect of the solar-array substrate on are duration are also presented. C1 NASA, George C Marshall Space Flight Ctr, Space Environm Effects Grp, Huntsville, AL 35812 USA. Sci Applicat Int Corp, Def Technol Grp, San Diego, CA 92121 USA. NASA, John H Glenn Res Ctr Lewis Field, Power & Prop Off, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr Lewis Field, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. RP Schneider, TA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Environm Effects Grp, ED31, Huntsville, AL 35812 USA. NR 15 TC 7 Z9 7 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 543 EP 549 DI 10.2514/1.5636 PG 7 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000020 ER PT J AU Mikellides, LG Jongeward, GA Schneider, T Peterson, T Kerslake, TW Snyder, D AF Mikellides, LG Jongeward, GA Schneider, T Peterson, T Kerslake, TW Snyder, D TI Solar arrays for direct-drive electric propulsion: Electron collection at high voltages SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 39th Joint Propulsion Conference CY JUL 20, 2003 CL Huntsville, AL SP AIAA, ASME, SAE, ASEE AB Solar array technologies that can empower electric thrusters in direct drive mode may provide significant mission benefits by reducing power processing, system complexity, weight, and cost over conventional systems. In direct-drive systems the solar arrays will operate at high voltages and must perform safely in the surrounding plasma environment, with minimal loss of performance due to parasitic current collection. For example, current state-of-the-art Hall effect thrusters in the kilowatt class require applied voltages of 300 V or higher. Results from experiments and modeling of electron current collection at high bias voltages (300-500 V) are presented. The experiments employed two sample solar array coupon technologies. A hollow cathode was used to emulate the induced environment around the solar arrays far from the Hall thruster and in nearby regions populated by charge-exchange plasma (10(12)-10(13) m(-3) and 0.5-1 eV). The measurements show that tens to hundreds of seconds are required before the collected current relaxes to a quasi-steady value. Comparisons with results from numerical calculations suggest that changes of the secondary electron yield properties of the dielectric materials may account for the observed current collection trends. C1 Sci Applicat Int Corp, Def Technol Grp, San Diego, CA 92121 USA. NASA, George C Marshall Space Flight Ctr, Space Environm Effects Grp, Huntsville, AL 35812 USA. NASA, John H Glenn Res Ctr Lewis Field, Power & Prop Off, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr Lewis Field, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. RP Mikellides, LG (reprint author), Sci Applicat Int Corp, Def Technol Grp, 10260 Campus Point Dr, San Diego, CA 92121 USA. NR 23 TC 1 Z9 1 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 2005 VL 42 IS 3 BP 550 EP 558 PG 9 WC Engineering, Aerospace SC Engineering GA 935BM UT WOS:000229754000021 ER PT J AU de la Mora, JF Thomson, BA Gamero-Castano, M AF de la Mora, JF Thomson, BA Gamero-Castano, M TI Tandem mobility mass spectrometry study of electrosprayed tetraheptyl ammonium bromide clusters SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID ION EVAPORATION; GAS-PHASE; CHARGED DROPLETS; ATMOSPHERIC-PRESSURE; NANOMETER PARTICLES; SOLVATION ENERGY; LIQUID SURFACES; SALT CLUSTERS; BORANE SALTS; IN-VACUO AB Multiply charged electrospray ions from concentrated solutions of Heptyl(4)N(+)Br(-) (designated A(+)B(-) hereafter) in formamide are analyzed mass spectrometrically (MS) following mobility selection in ambient air in a differential mobility analyzer (DMA). Most of the sharp mobility peaks seen are identified as (AB)(n)A(+) clusters, with 0 <= n <= 5. One anomalously abundant and mobile ion is identified as NH4+(AB)(4). Six ions in the (AB)(n)(A(+))(2) series are also identified, completing and correcting earlier mobility data for singly and doubly charged ions up to masses of almost 9000 Da. The more mobile of two broad humps seen in the mobility spectrum includes m/z values approximately from 2500 up to 12,000 Da. It is formed primarily by multiply charged (AB)(n)(A(+))(z) clusters with multiple ammonium bromide adducts. Because of overlapping of many peaks of different m/z and charge state z, only a few individual species can be identified by MS alone in this highly congested region. However, the spectral simplification brought about by mobility selection upstream of the MS reveals a series of broad modulations in m/z space, with all ions resolved in the second, third,.. sixth modulation being in charge states z = 2, 3,...6, respectively. Extrapolation of this trend beyond the sixth wave fixes the ion charge state (in some cases up to z = 15) and mass (beyond m = 175,000 u). This wavy structure had been previously observed and explained in terms of ion evaporation kinetics from volatile drops, though without mass identification. All observations indicate that the clusters are formed as charged residues, but their charge state is fixed by the Iribarne-Thomson ion evaporation mechanism. Consequently, the measured curve of cluster diameter versus z yields the two parameters governing ion evaporation kinetics. Clusters with z > I and electrical mobility Z > 0.495 cm(2)/V/s are metastable and evaporate a singly charged cluster, probably (AB)(2)A(+), between the DMA and the MS. Plotting the electrical mobilities Z of the clusters in the form (z/Z)(1/2) versus m(1/3) (both proportional to cluster diameter) collapse the data for all cluster sizes and charge states into one single straight line for Z below 0.495 cm(2)/V/s. This linear relation reveals a uniform apparent cluster density of 0.935 g/cm(3) and an effective hard-sphere diameter of the air molecules of 0.44 nm. An anomalous mobility increase is observed at diameters below 3 nm. (c) 2005 American Society for Mass Spectrometry. C1 Yale Univ, Dept Mech Engn, New Haven, CT 06520 USA. MDS Sciex, Concord, ON, Canada. Jet Propuls Lab, Pasadena, CA USA. RP de la Mora, JF (reprint author), Yale Univ, Dept Mech Engn, POB 208286, New Haven, CT 06520 USA. EM juan.delamora@yale.edu NR 48 TC 24 Z9 25 U1 0 U2 6 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1044-0305 EI 1879-1123 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD MAY PY 2005 VL 16 IS 5 BP 717 EP 732 DI 10.1016/j.jasms.2005.01.019 PG 16 WC Biochemical Research Methods; Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Biochemistry & Molecular Biology; Chemistry; Spectroscopy GA 922YE UT WOS:000228875000011 ER PT J AU Eitzen, ZA Randall, DA AF Eitzen, ZA Randall, DA TI Numerical simulations of interactions between gravity waves and deep moist convection SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NONHYDROSTATIC ATMOSPHERIC SIMULATION; QUASI-BIENNIAL OSCILLATION; VERTICAL VELOCITY EVENTS; LARGE-SCALE ENVIRONMENT; CUMULUS CLOUD ENSEMBLE; PREDICTION SYSTEM ARPS; COARE SQUALL LINE; TROPICAL CONVECTION; TOGA-COARE; MOMENTUM TRANSPORT AB This study uses a numerical model to simulate deep convection both in the Tropics over the ocean and the midlatitudes over land. The vertical grid that was used extends into the stratosphere. allowing for the simultaneous examination of the convection and the vertically propagating gravity waves that it generates. A large number of trajectories are used to evaluate the behavior of tracers in the troposphere, and it is found that the tracers can be segregated into different types based upon their position in a diagram of normalized vertical velocity versus displacement. Conditional sampling is also used to identify updrafts in the troposphere and calculate their contribution to the kinetic energy budget of the troposphere. In addition, Fourier analvsis is used to characterize the waves in the stratosphere; it was found that the waves simulated in this study have similarities to those observed and simulated by other researchers. Finally, this study examines the wave energy flux as a means to provide a link between the tropospheric behavior of the convection and the strength of the waves in the stratosphere. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Eitzen, ZA (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM z.a.eitzen@larc.nasa.gov RI Randall, David/E-6113-2011 OI Randall, David/0000-0001-6935-4112 NR 59 TC 3 Z9 5 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2005 VL 62 IS 5 BP 1480 EP 1496 DI 10.1175/JAS3418.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 929IB UT WOS:000229335800012 ER PT J AU Canuto, VM Cheng, Y Howard, AM AF Canuto, VM Cheng, Y Howard, AM TI What causes the divergences in local second-order closure models? SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CONVECTIVE BOUNDARY-LAYER; LARGE-EDDY SIMULATION; TURBULENCE CLOSURE; 3RD-ORDER MOMENTS; PBL MODEL; TRANSPORT; DIFFUSIVITY; BUOYANCY; ROTATION; SHEAR AB It has been known for three decades that in the case of buoyancy-driven flows the widely used second-order closure (SOC) level-2.5 turbulence models exhibit divergences that render them unphysical in certain domains. This occurs when the dimensionless temperature gradient G(h) (defined below) approaches a critical value G(h)(cr) of the order of 10; thus far, the divergerices have been treated with ad hoc limitations of the type G(h) <= G(h)(cr) similar to 10, G(h) equivalent to -tau(2) g alpha partial derivative T/partial derivative z, where tau is the eddy turnover time scale, g is the gravitational acceleration, g is the coefficient of thermal expansion, T is the mean potential temperature and z is the height. It must be noted that large eddy simulation (LES) data show no such limitation. The divergent results have the following implications. In most of the aT/az < 0 portion of a convective planetary boundary layer (PBL), a variety of data show that tau increases with z, -aT/az decreases with z, and G(h) decreases with G(h)(cr). As one approach's the surface laver from above, at some z(cr) (similar to 0.2H, H is the PBL height), G(h), approaches G(h)(cr) and the model results diverge. Below z(er), existing models assume the displayed equation above. Physically, this amounts to artificially making the eddy lifetime shorter than what it really is. Since short-lived eddies are small eddies, one is essentially changing-large eddies into small eddies. Since large eddies are the main contributors to bulk properties such as heat, momentum flux. etc., the artificial transformation of large eddies into small eddies is equivalent to underestimating the efficiency of turbulence (is a mixing process. In this paper the physical origin of the divergences is investigated. First, it is shown that it is due to the local nature of the level-2.5 models. Second. it is shown that once an appropriate nonlocal model is employed, all the divergences cancel out, yielding a finite result. An immediate implication of this result is the need for a reliable model for the third-order moments (TOMs) that represent nonlocality. The TOMs must not only compare well with LES data, but in addition, they must yield nondivergent second-order moments. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Math, New York, NY USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM vcanuto@giss.nasa.gov NR 20 TC 8 Z9 8 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY PY 2005 VL 62 IS 5 BP 1645 EP 1651 DI 10.1175/JAS3420.1 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 929IB UT WOS:000229335800024 ER PT J AU Rubiola, E Salik, E Huang, SH Yu, N Maleki, L AF Rubiola, E Salik, E Huang, SH Yu, N Maleki, L TI Photonic-delay technique for phase-noise measurement of microwave oscillators SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID SAPPHIRE RESONATOR; AM NOISE AB A photonic-delay line is used as a frequency discriminator for measurement of the phase noise-hence the short-term frequency stability-of microwave oscillators. The scheme is suitable for electronic and photonic oscillators, including the optoelectronic oscillator, mode lock lasers, and other types of rf and microwave pulsed optical sources. The approach is inherently suitable for a wide range of frequency without reconfiguration, which is important for the measurement of tunable oscillators. It is also insensitive to a moderate frequency drift without the need for phase locking. 2005 Optical Society of America. C1 Univ Henri Poincare, Ecole Super Sci & Technol Ingenieur Nancy, Nancy, France. Univ Henri Poincare, Lab Phys Milieux Ionises & Applicat, Nancy, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rubiola, E (reprint author), Univ Henri Poincare, Ecole Super Sci & Technol Ingenieur Nancy, Nancy, France. NR 32 TC 32 Z9 34 U1 1 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 2005 VL 22 IS 5 BP 987 EP 997 DI 10.1364/JOSAB.22.000987 PG 11 WC Optics SC Optics GA 924OZ UT WOS:000228989500006 ER PT J AU Chiao, L Sharipov, S Sargsyan, AE Melton, S Hamilton, DR McFarlin, K Dulchavsky, SA AF Chiao, L Sharipov, S Sargsyan, AE Melton, S Hamilton, DR McFarlin, K Dulchavsky, SA TI Ocular examination for trauma; Clinical ultrasound aboard the International Space Station SO JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE LA English DT Article DE ultrasound ocular aerospace; NASA ID FOCUSED ASSESSMENT; HEMOPERITONEUM; PNEUMOTHORAX; SONOGRAPHY AB Background. Ultrasound imaging is a successful modality in a broad variety of diagnostic applications including trauma. Ultrasound has been shown to be accurate when performed by non-radiologist physicians; recent reports have suggested that non-physicians can perform limited ultrasound examinations. A multipurpose ultrasound system is installed on the International Space Station (ISS) as a component of the Human Research Facility (HRF). This report documents the first ocular ultrasound examination conducted in space, which demonstrated the capability to assess physiologic alterations or pathology including trauma during long-duration space flight. Methods. An ISS crewmember with minimal sonography training was remotely guided by an imaging expert from Mission Control Center (MCC) through a comprehensive ultrasound examination of the eye. A multipurpose ultrasound imager was used in conjunction with a space-to-ground video downlink and two-way audio. Reference cards with topological reference points, hardware controls, and target images were used to facilitate the examination. Multiple views of the eye structures were obtained through a closed eyelid. Pupillary response to light was demonstrated by, modifying the light exposure of the contralateral eye. Results: A crewmember on the ISS was able to complete a comprehensive ocular examination using B- and M-mode ultrasonography with remote guidance from an expert in the MCC. Multiple anteroposterior, oblique, and coronal views of the eye clearly demonstrated the anatomic structures of both segments of the globe. The iris and pupil were readily visualized with probe manipulation. Pupillary diameter was assessed in real time in B- and M-mode displays. The anatomic detail and fidelity of ultrasound video were excellent and could be used to answer a variety of clinical and space physiologic questions. Conclusions: A comprehensive, high-quality ultrasound examination of the eye was performed with a multipurpose imager aboard the ISS by a nonexpert operator using remote guidance. Ocular ultrasound images were of diagnostic quality despite the 2-second communication latency and the unconventional setting of a weightless spacecraft environment. The remote guidance techniques developed to facilitate this successful NASA research experiment will support wider applications of ultrasound for remote medicine on Earth including the assessment of pupillary reactions in patients with severe craniofacial trauma and swelling. C1 Henry Ford Hosp, Dept Surg, Detroit, MI 48202 USA. NASA, Lyndon B Johnson Space Ctr, TX Wyle Labs, Houston, TX 77058 USA. RP Dulchavsky, SA (reprint author), Henry Ford Hosp, Dept Surg, 2799 W Grand Blvd, Detroit, MI 48202 USA. EM sdulcha1@hfhs.org RI shirzadeh, ebrahim/F-5382-2015 OI shirzadeh, ebrahim/0000-0001-6618-1236 NR 24 TC 35 Z9 36 U1 1 U2 5 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 1079-6061 J9 J TRAUMA JI J. Trauma-Injury Infect. Crit. Care PD MAY PY 2005 VL 58 IS 5 BP 885 EP 889 DI 10.1097/01.TA.0000162456.37962.01 PG 5 WC Critical Care Medicine; Surgery SC General & Internal Medicine; Surgery GA 932PU UT WOS:000229566600001 PM 15920397 ER PT J AU Mitchell, KL AF Mitchell, KL TI Coupled conduit flow and shape in explosive volcanic eruptions SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article; Proceedings Paper CT International Workshop on Volcanic Eruption Mechanisms - Insights from Model Intercomparison of Conduit Processes CY NOV, 2002 CL Durham, NH SP Nat; Sci Fdn DE volcanic; eruption; conduit; flow; erosion ID BASALTIC MAGMA; PLINIAN ERUPTION; AD 79; PRESSURE; VISCOSITIES; RESERVOIRS; MECHANISM; EVOLUTION; VESUVIUS; DYNAMICS AB Volcanic conduit flow models generally utilise one of two conduit profile modes, which are referred to as parallel-sided (typically surface choked) or lithostatically pressure-balanced. Their limitations in application to supersonically erupted basaltic and rhyolitic explosive eruptions are investigated. Likely changes in conduit profile over time, due to catastrophic failure resulting from high wall stresses, and abrasive erosion, are investigated using a semi-analytical model. Although time-independent, this model nonetheless reveals likely trends in shape from a simple parallel-sided geometry. It is found that, for rhyolites, early wall failure will occur in all but unusual circumstances, resulting in expansion of the conduit, a reduction in wall stresses, and a trend towards a lithostatically pressure-balanced solution at depth. In both rhyolitic and basaltic eruptions, abrasive erosion results in conduit flaring near the surface, allowing the choking point to descent from the surface into the vent, substantially changing exit conditions and resulting in a trend towards the a lithostatically pressure-balanced solution at the surface. Although a truly lithostatically pressure-balanced system can never be attained, due to the effects of compressibility at supersonic velocities, it is no less valid than the more commonly utilised parallel-sided system for a variety of realistic eruption scenarios and can be a useful guide for potential steady states. (c) 2005 Elsevier B.V. All rights reserved. C1 Univ Lancaster, Dept Environm Sci, Lancaster LA1 4YQ, England. RP Mitchell, KL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 183-601, Pasadena, CA 91109 USA. EM k.l.mitchell@lancaster.ac.uk NR 45 TC 26 Z9 26 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAY 1 PY 2005 VL 143 IS 1-3 BP 187 EP 203 DI 10.1016/j.jvolgeores.2004.09.017 PG 17 WC Geosciences, Multidisciplinary SC Geology GA 936RP UT WOS:000229873400011 ER PT J AU Bruyant, F Babin, M Genty, B Prasil, O Behrenfeld, MJ Claustre, H Bricaud, A Garczarek, L Holtzendorff, J Koblizek, M Dousova, H Partensky, F AF Bruyant, F Babin, M Genty, B Prasil, O Behrenfeld, MJ Claustre, H Bricaud, A Garczarek, L Holtzendorff, J Koblizek, M Dousova, H Partensky, F TI Diel variations in the photosynthetic parameters of Prochlorococcus strain PCC 9511: Combined effects of light and cell cycle SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID MAXIMUM QUANTUM YIELD; IN-VIVO FLUORESCENCE; CHLOROPHYLL FLUORESCENCE; THALASSIOSIRA-WEISSFLOGII; DIFFERENTIAL EXPRESSION; IRRADIANCE RELATIONSHIP; MARINE-PHYTOPLANKTON; DIVINYL-CHLOROPHYLL; POLAR PHYTOPLANKTON; EQUATORIAL PACIFIC AB We examined the mechanisms related to the diel variations in the parameters of the relationship between the rate of carbon fixation of phytoplankton and irradiance (P vs. E curve). Our goal was to understand what determines the phase of these variations relative to that of the light cycle. We grew the marine prokaryote Prochlorococcus in an axenic cyclostat culture system under a light-dark cycle that mimicked natural conditions at sea surface and followed changes in cell physiology with a 2-h resolution. Individual cells divide mostly in phase with each other, once a day at the beginning of the dark period. The quantum yields of chlorophyll fluorescence, the maximum quantum yield of carbon fixation and the maximum rate of carbon fixation (P-max(B)) exhibited diel variations over about factors of 2, 4, and 4, respectively, with maxima at the beginning of the light period. The morning drop in phi(Cmax) and the quantum yield of fluorescence, which was accompanied by only a small decrease (< 15%) of photochemial efficiency of PSII (F-v/F-m), suggests regulation by light and preceded the drop in P-max(B) by 4 h. The decrease in P-max(B) during the day matched a decrease in the transcription level of Rubisco. The quantum yield of fluorescence, phi(Cmax), and P-max(B) increased again during the dark period, but this recovery was slowed at the time of cell division. Our results suggest that the pattern of diel variations in the photosynthetic parameters is determined both by photoacclimation and the cell-division cycle. C1 IMB, NRC, Halifax, NS B3H 4J1, Canada. Univ Paris 06, Lab Oceanog Villefranche, F-06238 Villefranche Sur Mer, France. CNRS, F-06238 Villefranche Sur Mer, France. Univ Paris 11, Lab Ecophysiol Vegetale, F-91405 Orsay, France. CNRS, F-91405 Orsay, France. Acad Sci Czech Republ, Inst Microbiol, Photosynth Res Ctr, Trebon 37981, Czech Republic. Univ S Bohemia, Trebon 37981, Czech Republic. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Paris 06, Equipe Phytoplancton Ocean, Biol Stn, F-29682 Roscoff, France. CNRS, F-29682 Roscoff, France. Humboldt Univ, Inst Biol Genet, D-10115 Berlin, Germany. Acad Sci Czech Republ, Inst Microbiol, Photosynthesis Res Ctr, Trebon 37981, Czech Republic. Univ S Bohemia, Trebon 37981, Czech Republic. RP Bruyant, F (reprint author), Dalhousie Univ, Dept Oceanog, Halifax, NS B3H 4J1, Canada. RI Prasil, Ondrej/H-2454-2014; Koblizek, Michal/H-2851-2014; CLAUSTRE, Herve/E-6877-2011; OI Prasil, Ondrej/0000-0002-0012-4359; CLAUSTRE, Herve/0000-0001-6243-0258; Partensky, Frederic/0000-0003-1274-4050 NR 59 TC 37 Z9 37 U1 2 U2 14 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 2005 VL 50 IS 3 BP 850 EP 863 PG 14 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 928AO UT WOS:000229243700010 ER PT J AU Xiong, Y Olson, CF Matthies, LH AF Xiong, Y Olson, CF Matthies, LH TI Computing depth maps from descent images SO MACHINE VISION AND APPLICATIONS LA English DT Article DE planetary exploration; structure from motion; descent images; motion estimation; terrain mapping ID MOTION; ALGORITHM AB In the exploration of the planets of our solar system, images taken during a lander's descent to the surface of a planet provide a critical link between orbital images and surface images. The descent images not only allow us to locate the landing site in a global coordinate frame, but they also provide progressively higher-resolution maps for mission planning. This paper addresses the generation of depth maps from the descent images. Our approach has two steps, motion refinement and depth recovery. During motion refinement, we use an initial motion estimate in order to avoid the intrinsic motion ambiguity. The objective of the motion-refinement step is to adjust the motion parameters such that the reprojection error is minimized. The depth-recovery step correlates adjacent frames to match pixels for triangulation. Due to the descending motion, the conventional recti. cation process is replaced by a set of anti-aliasing image warpings corresponding to a set of virtual parallel planes. We demonstrate experimental results on synthetic and real descent images. C1 Univ Washington, Comp & Software Syst, Bothell, WA 98011 USA. KLA Tencor, San Jose, CA 95134 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), Univ Washington, Comp & Software Syst, 18115 Campus Way NE,Box 358534, Bothell, WA 98011 USA. EM cfolson@u.washington.edu NR 16 TC 7 Z9 11 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0932-8092 J9 MACH VISION APPL JI Mach. Vis. Appl. PD MAY PY 2005 VL 16 IS 3 BP 139 EP 147 DI 10.1007/s00138-004-0160-7 PG 9 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 918IT UT WOS:000228536200001 ER PT J AU Kharkovsky, S Hepburn, F Walker, J Zoughi, R AF Kharkovsky, S Hepburn, F Walker, J Zoughi, R TI Nondestructive testing of the space shuttle external tank foam insulation using near field and focused millimeter wave techniques SO MATERIALS EVALUATION LA English DT Article DE millimeter waves; near field; insulating foam; spray on foam insulation; unbond; void; focusing lens; horn antenna AB The space shuttle Columbia's catastrophic failure has been attributed to a piece of external tank spray on foam insulation striking the left wing of the orbiter, causing significant damage to some of the reinforced carbon/carbon leading edge wing panels. Subsequently, several nondestructive testing (NDT) techniques have been considered for testing the external tank. One such technique involves using millimeter waves, which have been shown to easily penetrate the foam and provide high resolution images of its interior structures. This paper presents the results of testing three different spray on foam insulation covered panels by reflectometers at millimeter wave frequencies, specifically at 100 GHz. Each panel was fitted with various embedded discontinuities/inserts representing voids and unbonds of different shapes, sizes and locations within each panel. In conjunction with these reflectometers, radiators, including a focused lens antenna and a small horn antenna, were used. The focused lens antenna provided for a footprint diameter of approximately 12.5 mm (0.5 in.) at 254 mm (10 in.) away from the lens surface. The horn antenna was primarily operated in its near field for obtaining relatively high resolution images. These images were produced using two dimensional scanning mechanisms. Discussion of the difference between the capabilities of these two types of antennas (radiators) for the purpose of testing the spray on foam insulation as it relates to the produced images is also presented. C1 Univ Missouri, Dept Elect & Comp Engn, Appl Microwave Nondestruct Testing Lab, Rolla, MO 65409 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Kharkovsky, S (reprint author), Univ Missouri, Dept Elect & Comp Engn, Appl Microwave Nondestruct Testing Lab, Rolla, MO 65409 USA. EM zoughir@umr.edu NR 8 TC 12 Z9 12 U1 1 U2 1 PU AMER SOC NONDESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAY PY 2005 VL 63 IS 5 BP 516 EP 522 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA 926NX UT WOS:000229131000007 ER PT J AU Bloomberg, JJ Mulavara, AP Peters, BT Cohen, HS Richards, JT Miller, CA Brady, R Warren, LE AF Bloomberg, Jacob J. Mulavara, Ajitkumar P. Peters, Brian T. Cohen, Helen S. Richards, Jason T. Miller, Chris A. Brady, Rachel Warren, Lara E. TI Development of Training Programs to Mitigate Post Space Flight Gait Dysfunction SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Baylor Coll Med, Natl Space Biomed Res Inst, Houston, TX 77030 USA. Wyle Life Sci, Houston, TX USA. Baylor Coll Med, Bobby R Alford Dept Otorhinolaryngol & Communicat, Houston, TX 77030 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2005 VL 37 SU 5 MA 1774 BP S343 EP S343 DI 10.1097/00005768-200505001-01773 PG 1 WC Sport Sciences SC Sport Sciences GA V19KC UT WOS:000208070302244 ER PT J AU Braun, WA Liang, M Dutto, D Bassin, S Cooper, D Wong, N Arnaud, S Markofski, M Plesums, K Huynh, H AF Braun, William A. Liang, Michael Dutto, Darren Bassin, Stanley Cooper, Dan Wong, Nathan Arnaud, Sara Markofski, Melissa Plesums, Karla Hung Huynh TI The Effects Of Exercise Training Mode On Biochemical Indices Of Bone Turnover And Bone Density In Untrained, Young Women SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract C1 [Braun, William A.] Shippensburg Univ, Shippensburg, PA 17257 USA. [Liang, Michael; Bassin, Stanley; Markofski, Melissa; Plesums, Karla; Hung Huynh] Calif State Polytech Univ Pomona, Pomona, CA 91768 USA. [Dutto, Darren] Eastern Oregon Univ, La Grande, OR USA. [Cooper, Dan; Wong, Nathan] Univ Calif Irvine, Irvine, CA USA. [Arnaud, Sara] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM wabrau@ship.edu RI Markofski, Melissa/Q-6372-2016 OI Markofski, Melissa/0000-0003-0214-4246 NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2005 VL 37 SU 5 MA 812 BP S150 EP S150 DI 10.1097/00005768-200505001-00810 PG 1 WC Sport Sciences SC Sport Sciences GA V19KC UT WOS:000208070301063 ER PT J AU Diaz, FJ Melchor, T Garcia, R Montano, JG Sanchez, MA Garciduenas, FD Hagan, DR Najera, M AF Diaz, Francisco J. Melchor, T. Garcia, R. Montano, J. G. Sanchez, M. A. Garciduenas, F. Diaz Hagan, Donald R. Najera, M. TI Prevalence Of Coronary Risk Factors In Boys And Girls 14-18 Years Of Age SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract C1 [Diaz, Francisco J.; Melchor, T.; Garcia, R.; Montano, J. G.; Sanchez, M. A.; Garciduenas, F. Diaz; Najera, M.] Univ Guanajuato, Leon, Mexico. [Hagan, Donald R.] NASA Johnson Space Ctr, Houston, TX USA. EM msanchez@webtelmex.net.mx NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2005 VL 37 SU 5 MA 2249 BP S433 EP S433 DI 10.1097/00005768-200505001-02248 PG 1 WC Sport Sciences SC Sport Sciences GA V19KC UT WOS:000208070302589 ER PT J AU Goodwin, TJ McCarthy, MA Dennis, RG AF Goodwin, Thomas J. McCarthy, Maureen A. Dennis, Robert G. TI Physiological And Molecular Genetic Effects Of Time Varying Electromagnetic Fields (TVEMF) On Human Neuronal Cells SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract C1 [Goodwin, Thomas J.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. [McCarthy, Maureen A.] Univ Space Res Assoc, Houston, TX USA. [Dennis, Robert G.] Univ N Carolina, Chapel Hill, NC USA. EM thomas.j.goodwin@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2005 VL 37 SU 5 MA 869 BP S163 EP S163 DI 10.1097/00005768-200505001-00867 PG 1 WC Sport Sciences SC Sport Sciences GA V19KC UT WOS:000208070301120 ER PT J AU Soller, BR Shear, M Walz, M Landry, M Heard, S Hagan, RD AF Soller, Babs R. Shear, Michael Walz, Matthias Landry, Michelle Heard, Stephen Hagan, R. Donald TI Comparison Of Interstitial Fluid Ph, Pco2, Po2 With Venous Blood Values During Repetitive Handgrip Exercise SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Meeting Abstract C1 [Soller, Babs R.; Shear, Michael; Walz, Matthias; Landry, Michelle; Heard, Stephen] UMass Med Sch, Worcester, MA USA. [Hagan, R. Donald] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM babs.soller@umassmed.edu NR 0 TC 0 Z9 0 U1 1 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 2005 VL 37 SU 5 MA 2002 BP S387 EP S387 DI 10.1097/00005768-200505001-02001 PG 1 WC Sport Sciences SC Sport Sciences GA V19KC UT WOS:000208070302417 ER PT J AU Mittlefehldt, DW AF Mittlefehldt, DW TI Ibitira: A basaltic achondrite from a distinct parent asteroid and implications for the Dawn mission SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID OXYGEN-ISOTOPE; 4 VESTA; EUCRITE; METEORITES; DIFFERENTIATION; DIOGENITES; HOWARDITE; SPACE; BODY; MINERALOGY AB I have done a detailed petrologic study of Ibitira, a meteorite that has been classified as a basaltic eucrite since 1957. The mean Fe/Mn ratio of pyroxenes in Ibitira with <10 mole% wollastonite component is 36.4 +/- 0.4; this value is well resolved from those of similar pyroxenes in five basaltic eucrites studied for comparison, which range from 31.2 to 32.2. Data for the latter five eucrites completely overlap. Ibitira pyroxenes have lower Fe/Mg than the basaltic eucrite pyroxenes; thus, the higher Fe/Mn ratio does not reflect a simple difference in oxidation state. Ibitira also has an oxygen isotopic composition, alkali element contents, and a Ti/Hf ratio that distinguish it from basaltic eucrites. These differences support derivation from a distinct parent asteroid. Thus, Ibitira is the first recognized representative of the fifth known asteroidal basaltic crust, the others being the HED, mesosiderite, angrite, and NWA 0 11 parent asteroids. 4 Vesta is generally assumed to be the HED parent asteroid. The Dawn mission will orbit 4 Vesta and will perform detailed mapping and mineralogical, compositional, and geophysical Studies of the asteroid. Ibitira is only subtly different from eucritic basalts. A challenge for the Dawn mission will be to distinguish different basalt types on the surface and to attempt to determine whether 4 Vesta is indeed the HED parent asteroid. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Mittlefehldt, DW (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code KR,2101 NASA Pkwy, Houston, TX 77058 USA. EM david.w.mittlefehldt@nasa.gov NR 39 TC 36 Z9 36 U1 2 U2 8 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAY PY 2005 VL 40 IS 5 BP 665 EP 677 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 952XX UT WOS:000231040700002 ER PT J AU Friedmann, EI Sun, HJ AF Friedmann, EI Sun, HJ TI Communities adjust their temperature optima by shifting producer-to-consumer ratio, shown in lichens as models: I. Hypothesis SO MICROBIAL ECOLOGY LA English DT Article ID CRYPTOENDOLITHIC MICROBIAL ENVIRONMENT; VICTORIA-LAND; ROSS DESERT; DRY VALLEYS; ANTARCTICA; GROWTH; BACTERIA AB An apparent paradox exists in the ecology of Antarctic lichens: their net photosynthetic temperature optimum (around 0 degrees C) lies far below the temperature optima of their constituent algae and fungi ( around 20 degrees C). To address this paradox, we consider lichens as microbial communities and propose the "community adaptation'' hypothesis, which posits that in each thermal regime there is an equilibrium between photosynthetic primary producers (photobionts), and heterotrophic consumers (mycobiont and parasymbiont fungi). This equilibrium, expressed as the producer/consumer ratio (R-p/c), maximizes the fitness of the community. As respiration increases with temperature, more rapidly than does photosynthesis, R-p/c will shift accordingly in warm habitats, resulting in a high-growth temperature optimum for the community (the lichen). This lends lichens an adaptive flexibility that enables them to function optimally at any thermal regime within the tolerance limits of the constituent organisms. The variable equilibrium of producers and consumers may have a similar role in thermal adaptation of more complex communities and ecosystems. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Desert Res Inst, Las Vegas, NV 89119 USA. RP Friedmann, EI (reprint author), NASA, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM ifriedmann@mail.arc.nasa.gov NR 43 TC 14 Z9 15 U1 1 U2 7 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD MAY PY 2005 VL 49 IS 4 BP 523 EP 527 DI 10.1007/s00248-005-3680-4 PG 5 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 962AY UT WOS:000231704600004 PM 15891938 ER PT J AU Sun, HJ Friedmann, EI AF Sun, HJ Friedmann, EI TI Communities adjust their temperature optima by shifting producer-to-consumer ratio, shown in lichens as models: II. Experimental verification SO MICROBIAL ECOLOGY LA English DT Article ID ROSS DESERT; PHOTOSYNTHESIS; ENVIRONMENT; ANTARCTICA; MORPHOLOGY; PHYSIOLOGY; PHOTOBIONT AB The community adaptation hypothesis [7] predicts that lichens, simple communities of microorganisms, can adapt to a wide range of thermal regimes by regulating the ratio of primary producers (algae) and consumers (fungi): R-p/c. To test this hypothesis, we determined R-p/c values by image analysis of cross sections of herbarium specimens of the lichen Cladina rangiferina, which is widely distributed between the Arctic and the tropics. We found that R-p/c for C. rangiferina increases with summer temperature by more than one order of magnitude, consistent with the hypothesis. To assess the ecological significance of community adaptation (R-p/c regulation), other adaptive mechanisms (e.g., photobiont substitution, genetic adaptation, and photosynthetic acclimation in North American Cladina spp.) were studied. Laboratory investigations with algae and fungi isolated in culture from live specimens suggested that the role of these mechanisms is relatively minor and cannot account for the high degree of lichen adaptability. C1 Desert Res Inst, Las Vegas, NV 89119 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sun, HJ (reprint author), Desert Res Inst, 755 E Flamingo Rd, Las Vegas, NV 89119 USA. EM henry.sun@dri.edu NR 24 TC 21 Z9 22 U1 1 U2 8 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD MAY PY 2005 VL 49 IS 4 BP 528 EP 535 DI 10.1007/s00248-005-3679-x PG 8 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 962AY UT WOS:000231704600005 PM 15900395 ER PT J AU Morgan, M Weinreb, S AF Morgan, M Weinreb, S TI Techniques for the integration of high-Q millimeter-wave filters in multi-function MMIC modules SO MICROWAVE JOURNAL LA English DT Article ID TRANSITIONS; DESIGN C1 Natl Radio Astron Observ, Charlottesville, VA 22903 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Morgan, M (reprint author), Natl Radio Astron Observ, Charlottesville, VA 22903 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU HORIZON HOUSE PUBLICATIONS INC PI NORWOOD PA 685 CANTON ST, NORWOOD, MA 02062 USA SN 0192-6225 J9 MICROWAVE J JI Microw. J. PD MAY PY 2005 VL 48 IS 5 BP 182 EP + PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 929DC UT WOS:000229321300007 ER PT J AU Uttley, P McHardy, IM Vaughan, S AF Uttley, P McHardy, IM Vaughan, S TI Non-linear X-ray variability in X-ray binaries and active galaxies SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : data analysis; methods : statistical; galaxies : active; X-rays : binaries; X-rays : galaxies; X-rays : individual : Cygnus X-1 ID LINE SEYFERT-1 GALAXY; ACCRETING BLACK-HOLES; LONG-TERM VARIABILITY; BAND POWER SPECTRA; CYGNUS X-1; RAPID VARIABILITY; GALACTIC NUCLEI; TIME-SERIES; NGC 4051; NOISE AB We show that the rms-flux relation recently discovered in the X-ray light curves of active galactic nuclei (AGN) and X-ray binaries (XRBs) implies that the light curves have a formally non-linear, exponential form, provided the rms-flux relation applies to variations on all time-scales (as it appears to). This phenomenological model implies that stationary data will have a lognormal flux distribution. We confirm this result using an observation of Cyg X-1, and further demonstrate that our model predicts the existence of the powerful millisecond flares observed in Cyg X-1 in the low/hard state, and explains the general shape and amplitude of the bicoherence spectrum in that source. Our model predicts that the most variable light curves will show the most extreme non-linearity. This result can naturally explain the apparent non-linear variability observed in some highly variable narrow line Seyfert 1 (NLS1) galaxies, as well as the low states observed on long time-scales in the NLS1 NGC 4051, as being nothing more than extreme manifestations of the same variability process that is observed in XRBs and less variable AGN. That variability process must be multiplicative (with variations coupled together on all time-scales) and cannot be additive (such as shot-noise), or related to self-organized criticality, or result from completely independent variations in many separate emitting regions. Successful models for variability must reproduce the observed rms-flux relation and non-linear behaviour, which are more fundamental characteristics of the variability process than the power spectrum or spectral-timing properties. Models where X-ray variability is driven by accretion rate variations produced at different radii remain the most promising. C1 NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Univ Leicester, Dept Phys & Astron, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. RP Uttley, P (reprint author), NASA, Goddard Space Flight Ctr, LHEA, Code 662, Greenbelt, MD 20771 USA. EM pu@milkyway.gsfc.nasa.gov NR 77 TC 177 Z9 176 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 2005 VL 359 IS 1 BP 345 EP 362 DI 10.1111/j.1365-2966.2005.08886.x PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917SF UT WOS:000228488800031 ER PT J AU Matsuura, M Zijlstra, AA Molster, FJ Waters, LBFM Nomura, H Sahai, R Hoare, MG AF Matsuura, M Zijlstra, AA Molster, FJ Waters, LBFM Nomura, H Sahai, R Hoare, MG TI The dark lane of the planetary nebula NGC 6302 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE dust, extinction; ISM : jets and outflows; planetary nebulae : individual : NGC 6302 ID INTERMEDIATE-MASS STARS; NGC 6302; SUBMILLIMETER CONTINUUM; RADIO OBSERVATIONS; STELLAR EVOLUTION; RED-RECTANGLE; ISO SPECTRUM; EMISSION; DUST; SPECTROSCOPY AB The butterfly-shaped planetary nebula, NGC 6302, shows a unique, dense equatorial dark lane, which is presumably a dusty disc, obscuring an unobserved, very hot central star. We trace the structure of this disc using Hubble Space Telescope H alpha and [N II] images, Very Large Telescope L- and M-band images at 0.4-arcsec resolution, including Bra and polycyclic aromatic hydrocarbon (PAH) images, and a James Clerk Maxwell Telescope 450-mu m image. Extinction maps are derived from these images. Within the disc, the extinction is A(H alpha) = 5 - 7 mag and A(Br alpha) = 1 - 2 mag. The 450-mu m map shows a north - south elongated central core, tracing the massive dust disc, and extended emission from dust in the bipolar flows. A fit to the spectral energy distribution yields the disc dust mass of 0.03 M(.). The innermost region shows an ionized shell. The orientation of the polar axis shows a marked change between shell, disc and inner and outer outflow. The structures are well described by the warped-disc model of Icke ( 2003). PAH images are presented: PAH emission is found in the shell but avoids the disc. An infrared source is found close to the expected location of the central star. C1 Univ Manchester, Dept Phys & Astron, Manchester M60 1QD, Lancs, England. European Space Agcy, Estec, NL-2201 AZ Noordwijk, Netherlands. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Heverlee, Belgium. Kobe Univ, Grad Sch Sci & Technol, Dept Earth & Planetary Sci, Kobe, Hyogo 6578501, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. RP Matsuura, M (reprint author), Univ Manchester, Dept Phys & Astron, Sackville St,POB 88, Manchester M60 1QD, Lancs, England. EM m.matsuura@manchester.ac.uk NR 67 TC 31 Z9 31 U1 2 U2 6 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 2005 VL 359 IS 1 BP 383 EP 400 DI 10.1111/j.1365-2966.2005.08903.x PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917SF UT WOS:000228488800033 ER PT J AU Khan, SA Benford, DJ Clements, DL Shafer, RA Sumner, TJ AF Khan, SA Benford, DJ Clements, DL Shafer, RA Sumner, TJ TI Resolving IRAS 09111-1007 at 350 mu m: a different path to ULIRG formation? SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : individual : IRAS 09111-1007; galaxies : interactions; galaxies : seyfert; galaxies : starburst; infrared : galaxies ID ULTRALUMINOUS INFRARED GALAXIES; INTERACTING GALAXIES; STAR FORMATION; COLD DUST; SHARC-II; MERGERS; SAMPLE; STARBURSTS; LUMINOSITY; EMISSION AB We have resolved the ultraluminous infrared galaxy (ULIRG) IRAS 09111-1007 with the new 350-mu m-optimized Second Generation Submillimeter High Angular Resolution Camera (SHARC II), and present the first submillimetre fluxes and images for the system. IRAS 09111-1007 comprises two interacting luminous infrared galaxies (LIRGs) with a projected nuclear separation of 39 h(71)(1) kpc. The western galaxy is roughly four times more luminous in the submillimetre than its eastern counterpart. It is an extremely bright LIRG with an active galactic nucleus (AGN). The classification of the eastern source is uncertain: it could be a Seyfert 2 galaxy or a LINER. We highlight IRAS 09111-1007 as a system that necessitates further study: a double AGN ULIRG whose molecular gas content differs from that of other widely separated pairs, and whose ULIRG phase might not be explained by current multiple-merger and/or final-stage ULIRG scenarios. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2AZ, England. NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Greenbelt, MD 20771 USA. RP Khan, SA (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Prince Consort Rd, London SW7 2AZ, England. EM khan@stars.gsfc.nasa.gov RI Benford, Dominic/D-4760-2012 OI Benford, Dominic/0000-0002-9884-4206 NR 45 TC 5 Z9 5 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 2005 VL 359 IS 1 BP L10 EP L14 DI 10.1111/j.1745-3933.2005.00024.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917SF UT WOS:000228488800036 ER PT J AU Siqueira, JR Rossow, WB Machado, LAT Pearl, C AF Siqueira, JR Rossow, WB Machado, LAT Pearl, C TI Structural characteristics of convective systems over South America related to cold-frontal incursions SO MONTHLY WEATHER REVIEW LA English DT Article ID TRMM PRECIPITATION RADAR; LIFE-CYCLE; MESOSCALE; LINE; VARIABILITY; COMPLEXES; RAINFALL; ISCCP AB International Satellite Cloud Climatology Project (ISCCP DX) and microwave sensor data collected by the Tropical Rainfall Measuring Mission (TRMM) are used to identify and describe structural characteristics of convective systems (CSs) over continental South America (SA) related to cold-frontal incursions in a 3-yr period. An austral wet-season climatology for CS events of the three most important types of front-tropical convection interaction is built by applying latitude-time diagrams and a cloud-tracking method to DX data. Type 1 is characterized by the penetration of a cold front over subtropical SA that interacts with convection and moves with it into lower tropical latitudes. Type 2 refers to Amazon convection and its enhancement in a quasi -stationary northwest-southeast-oriented band extending from the Amazon to subtropical SA along with the passage of a cold front in the subtropics and characterizes the synoptic formation of the South Atlantic convergence zone. A quasi-stationary cold front over subtropical SA that has only weak interaction with tropical convection corresponds to type 3. Results show that the three types of front-tropical convection interaction strongly modulate deep convection over SA, producing mesoscale CSs with significant fractions of deep convective clouds and rain at their mature phase. Type 2 CSs (type 1 CSs) are constituted of larger deep convective cloud fractions with weaker (stronger) vertical development compared to type 1 CSs (type 3 CSs) in the Tropics (subtropics), resulting in larger rain fractions and less (more) presence of convective rain. Type 1 CSs have larger fractions of deep convective clouds and rain but with weaker vertical development in the subtropics than in the Tropics, showing that cold fronts organize convection more in area in the subtropics, but more in vertical extent in the Tropics. Life cycle variations of CS cloud and rain properties show tropical CSs with a more intense initial development and similar structural differences between the CS types and those found at their mature phase. C1 Inst Nacl Pesquisas Espaciais, Div Meio Ambiente & Clima, Ctr Previsao Tempo & Estudos Climat, BR-12201970 Sao Jose Dos Campos, SP, Brazil. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. SGT Inc, New York, NY USA. RP Siqueira, JR (reprint author), Inst Nacl Pesquisas Espaciais, Div Meio Ambiente & Clima, Ctr Previsao Tempo & Estudos Climat, Avenida Astronautas,1758 Jardim Granja, BR-12201970 Sao Jose Dos Campos, SP, Brazil. EM jricardo@cptec.inpe.br RI Machado, Luiz/C-4314-2012; Rossow, William/F-3138-2015 OI Machado, Luiz/0000-0002-8243-1706; NR 28 TC 14 Z9 14 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2005 VL 133 IS 5 BP 1045 EP 1064 DI 10.1175/MWR2888.1 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 930CH UT WOS:000229392900001 ER PT J AU Menemenlis, D Fukumori, I Lee, T AF Menemenlis, D Fukumori, I Lee, T TI Using Green's functions to calibrate an ocean general circulation model SO MONTHLY WEATHER REVIEW LA English DT Article ID SATELLITE ALTIMETRY; DATA ASSIMILATION; PACIFIC-OCEAN; TRANSPORTS; BOUNDARY; CLIMATE; FLUXES; VOLUME; HEAT AB Green's functions provide a simple yet effective method to test and to calibrate general circulation model (GCM) parameterizations, to study and to quantify model and data errors, to correct model biases and trends, and to blend estimates from different solutions and data products. The method is applied to an ocean GCM, resulting in substantial improvements of the solution relative to observations when compared to prior estimates: overall model bias and drift are reduced and there is a 10%-30% increase in explained variance. Within the context of this optimization, the following new estimates for commonly used ocean GCM parameters are obtained. Background vertical diffusivity is (15.1 +/- 0.1) X 10(-6) m(2) s(-2). Background vertical viscosity is (18 +/- 3) x 10(-6) m(2) s(-2). The critical bulk Richardson number, which sets boundary layer depth, is Ri(c), = 0.354 +/- 0.004. The threshold gradient Richardson number for shear instability vertical mixing is Rio = 0.699 +/- 0.008. The estimated isopycnal diffusivity coefficient ranges from 550 to 1350 m(2) s(-2), with the largest values occurring at depth in regions of increased mesoscale eddy activity. Surprisingly, the estimated isopycnal diffusivity exhibits a 5%-35% decrease near the surface. Improved estimates of initial and boundary conditions are also obtained. The above estimates are the backbone of a quasi-operational, global-ocean circulation analysis system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Menemenlis, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 300-323, Pasadena, CA 91109 USA. EM menemenlis@jpl.nasa.gov NR 33 TC 81 Z9 83 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2005 VL 133 IS 5 BP 1224 EP 1240 DI 10.1175/MWR2912.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 930CH UT WOS:000229392900011 ER PT J AU Manney, GL Allen, DR Kruger, K Naujokat, B Santee, ML Sabutis, JL Pawson, S Swinbank, R Randall, CE Simmons, AJ Long, C AF Manney, GL Allen, DR Kruger, K Naujokat, B Santee, ML Sabutis, JL Pawson, S Swinbank, R Randall, CE Simmons, AJ Long, C TI Diagnostic comparison of meteorological analyses during the 2002 antarctic winter SO MONTHLY WEATHER REVIEW LA English DT Article ID SOUTHERN-HEMISPHERE; POLAR VORTEX; STRATOSPHERIC ANALYSES; NORTHERN-HEMISPHERE; FEBRUARY 1979; OZONE; TRANSPORT; MODEL; REANALYSIS; SIMULATIONS AB Several meteorological datasets, including U.K. Met Office (MetO), European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), and NASA's Goddard Earth Observation System (GEOS-4) analyses, are being used in studies of the 2002 Southern Hemisphere (SH) stratospheric winter and Antarctic major warming. Diagnostics are compared to assess how these studies may be affected by the meteorological data used. While the overall structure and evolution of temperatures, winds, and wave diagnostics in the different analyses provide a consistent picture of the large-scale dynamics of the SH 2002 winter, several significant differences may affect detailed studies. The NCEP-NCAR reanalysis (REAN) and NCEP-Department of Energy (DOE) reanalysis-2 (REAN-2) datasets are not recommended for detailed studies, especially those related to polar processing, because of lower-stratospheric temperature biases that result in underestimates of polar processing potential, and because their winds and wave diagnostics show increasing differences from other analyses between similar to 30 and 10 hPa (their top level). Southern Hemisphere polar stratospheric temperatures in the ECMWF 40-Yr Re-analysis (ERA-40) show unrealistic vertical structure, so this long-term reanalysis is also unsuited for quantitative studies. The NCEP/Climate Prediction Center (CPC) objective analyses give an inferior representation of the upper-stratospheric vortex. Polar vortex transport barriers are similar in all analyses, but there is large variation in the amount, patterns, and timing of mixing, even among the operational assimilated datasets (ECMWF, MetO, and GEOS-4). The higher-resolution GEOS-4 and ECMWF assimilations provide significantly better representation of filamentation and small-scale structure than the other analyses, even when fields gridded at reduced resolution are studied. The choice of which analysis to use is most critical for detailed transport studies (including polar process modeling) and studies involving synoptic evolution in the upper stratosphere. The operational assimilated datasets are better suited for most applications than the NCEP/CPC objective analyses and the reanalysis datasets (REAN/REAN-2 and ERA-40). C1 New Mexico Highlands Univ, Dept Nat Sci, Sch Educ, Las Vegas, NM 87701 USA. New Mexico Highlands Univ, Dept Math Sci, Las Vegas, NM 87701 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Free Univ Berlin, Inst Meteorol, D-1000 Berlin, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Met Off, Exeter, Devon, England. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NOAA, Climate Predict Ctr, Camp Springs, MD USA. RP New Mexico Highlands Univ, Dept Nat Sci, Sch Educ, Las Vegas, NM 87701 USA. EM manney@mls.jpl.nasa.gov RI Pawson, Steven/I-1865-2014; Randall, Cora/L-8760-2014 OI Pawson, Steven/0000-0003-0200-717X; Randall, Cora/0000-0002-4313-4397 NR 47 TC 27 Z9 27 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2005 VL 133 IS 5 BP 1261 EP 1278 DI 10.1175/MWR2926.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 930CH UT WOS:000229392900013 ER PT J AU Teplitz, VL Kazanas, D Herrin, ET AF Teplitz, VL Kazanas, D Herrin, ET TI Double header: (1) quark nugget; (2) quinton radiation SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT 6th UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe CY FEB 18-20, 2004 CL Marina del Rey, CA ID DIMENSIONS AB (1) Quark nugget. Twenty years ago, Witten pointed out that matter made of up, down and strange quarks is (by the Pauli Principle) more likely to be stable than matter made of just up and down. If stable, it could exist in macroscopic nuggets of nuclear densities. We searched about a million seismic reports to the US Geological Survey (1990-1993) for evidence of such (multi-ton) nuggets passing through the Earth. We found one set of 9 reports with first signal timing and directions and subsequent wave forms all consistent with nugget passage, but not consistent with point events such as Earthquakes, nor with statistics of random reports. Others, however, showed that our results were incorrect because of a problem with the clock of one reporting station. (2) Quinton radiation. If the accelerating expansion of the universe is due to a quintessence field, radiation of quintessence quanta (or "quintons" I like to call them) could be an energy loss mechanism for binary systems. We calculated its strength assuming only the minimal interaction required by general covariance. We considered both the case in which the zero order field varies only over cosmic times and distances and that in which it is modified my nearby masses. For the former, the effect is too small to be observable. For the latter, we bound a parameter in the quintessence field solution in the presence of a large mass by requiring that the effect be small for the Hulse-Taylor pulsar. (C) 2005 Elsevier B.V. All rights reserved. C1 So Methodist Univ, Dept Geol Sci, Dallas, TX 75725 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Teplitz, VL (reprint author), So Methodist Univ, Dept Phys, Dallas, TX 75725 USA. EM vigdor.l.teplitz@nasa.gov NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD MAY PY 2005 VL 49 IS 2-6 BP 119 EP 124 DI 10.1016/j.newar.2005.01.041 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 932SD UT WOS:000229572800016 ER PT J AU Daidzic, NE Schmidt, E Hasan, MM Altobelli, S AF Daidzic, NE Schmidt, E Hasan, MM Altobelli, S TI Gas-liquid phase distribution and void fraction measurements using MRI SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 3rd International Symposium on Two Phase Modelling and Experimentation CY SEP 20-24, 2004 CL Pisa, ITALY ID NUCLEAR-MAGNETIC-RESONANCE; FLOW; NMR AB We used a permanent-magnet magnetic resonance imaging (MRI) system to estimate the integral, spatially- and temporally-resolved void fraction distributions and flow patterns in vertical gas-liquid two-phase flow. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. The air flow rate was in upward vertical direction against the gravity vector. Air flow rates were varied between 1 and 200 ml/min. Bubble formation and detachment at the inlet of the vertical column was non-uniform. The cylindrical non-conducting test tube in which two-phase flow is characterized was placed in a 0.26 T permanent-magnet MRI unit. A roughly linear relationship has been observed for the integral void fraction versus volume flow rate of air through vertical stagnant liquid column. Integral or sample-averaged void fraction was obtained by volume-averaging of the spatially-resolved signals. Spatial averaging was performed in a radial or longitudinal axis of the column. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI can indeed provide qualitative and quantitative data and is especially well suited for characterization of averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows. Better and faster MRI sequences could improve spatial and temporal resolutions significantly. (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, John H Glenn Res Ctr, NCSER, Cleveland, OH 44135 USA. New Mexico Resonance, Albuquerque, NM 87106 USA. RP Daidzic, NE (reprint author), NASA, John H Glenn Res Ctr, NCSER, 21000 Brookpk Rd,MS 110-3, Cleveland, OH 44135 USA. EM Nihad.Daidzic@grc.nasa.gov OI Daidzic, Nihad/0000-0001-6262-110X NR 19 TC 14 Z9 15 U1 2 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 2005 VL 235 IS 10-12 BP 1163 EP 1178 DI 10.1016/j.nucengdes.2005.02.024 PG 16 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 939MX UT WOS:000230078200011 ER PT J AU Horvath, I Norris, JP Scargle, JD Balazs, LG AF Horvath, I Norris, JP Scargle, JD Balazs, LG TI Preliminary results of the analysis of the BATSE TTE data SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-GEOPHYSICS AND SPACE PHYSICS LA English DT Article; Proceedings Paper CT 4th Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 18-22, 2004 CL Rome, ITALY AB The Compton Gamma Ray Observatory (CGRO) observed many types of data and one of them is the time-tagged photon events (TTE data). We use the Bayesian block analysis, using Bayesian statistics, analyses the TTE data. Our results; calculations of duration (T100), count rates (burst photon numbers in different channels) and count peaks (in 64, 16 and 4ms). We present the duration, the peak duration and the distance between peaks distributions. Principal Component Analysis (PCA) has been also applied. The PCA shows interesting results, such as channel 4 (highest energy channel) probably is very important. C1 Bolyai Mil Univ, Dept Phys, H-1456 Budapest, Hungary. NASA, Goddard Space Flight Ctr, GLAST Sci Support Ctr, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Konkoly Observ Budapest, H-1525 Budapest, Hungary. RP Horvath, I (reprint author), Bolyai Mil Univ, Dept Phys, POB 12, H-1456 Budapest, Hungary. NR 10 TC 1 Z9 1 U1 0 U2 0 PU SOCIETA ITALIANA DI FISICA PI BOLOGNA PA VIA SARAGOZZA, 12, I-40123 BOLOGNA, ITALY SN 1124-1896 J9 NUOVO CIMENTO C JI Nuovo Cimento Soc. Ital. Fis. C-Geophys. Space Phys. PD MAY-JUN PY 2005 VL 28 IS 3 BP 291 EP 294 DI 10.1393/ncc/i2005-10043-3 PG 4 GA 989AT UT WOS:000233646000011 ER PT J AU Hurley, K Briggs, M Kippen, RM Kouveliotou, C Meegan, C Fishman, G Cline, T Trombka, J McClanahan, T Boer, M Stern, B Kommers, J Mazets, E Golenetskii, S Goldsten, J Feroci, M Frontera, F Guidorzi, C Montanari, E Lewin, W Sinha, S Seetha, S AF Hurley, K Briggs, M Kippen, RM Kouveliotou, C Meegan, C Fishman, G Cline, T Trombka, J McClanahan, T Boer, M Stern, B Kommers, J Mazets, E Golenetskii, S Goldsten, J Feroci, M Frontera, F Guidorzi, C Montanari, E Lewin, W Sinha, S Seetha, S TI The interplanetary network supplements to the BATSE 5B and untriggered burst catalogs SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-GEOPHYSICS AND SPACE PHYSICS LA English DT Article; Proceedings Paper CT 4th Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 18-22, 2004 CL Rome, ITALY ID GAMMA-RAY BURSTS; ARRIVAL-TIME LOCALIZATIONS; PIONEER-VENUS-ORBITER; ULYSSES SUPPLEMENT AB We describe Interplanetary Network (IPN) detection and localization information for 554 gamma-ray bursts (GRBs) observed as triggered and untriggered events by BATSE. For any given burst observed by BATSE and one other distant spacecraft, arrival time analysis (or "triangulation") results in an annulus of possible arrival directions whose half-width varies between 14 arcseconds and 5.6 degrees, depending on the intensity, time history, and arrival direction of the burst, as well as the distance between the spacecraft. This annulus generally intersects the BATSE error circle, resulting in a reduction of the area of up to a factor of similar to 650. When three widely separated spacecraft observed a burst, the result is an error box whose area is as much as 30000 times smaller than that of the BATSE error circle. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, MSFC, NSSTC, Huntsville, AL 35805 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. St Michel Observ, Observ Haute Provence, St Michel, France. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Lebedev Phys Inst, Ctr Astro Space, Moscow 117810, Russia. Stockholm Observ, SCFAB, SE-10691 Stockholm, Sweden. MIT, Lincoln Lab, Lexington, MA 02420 USA. Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. CNR, Ist Astrofis Spaziale, I-00133 Rome, Italy. CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, I-40129 Bologna, Italy. Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Space Astron & Instrumentat Div, ISRO, Satellite Ctr, Bangalore 560017, Karnataka, India. RP Hurley, K (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI McClanahan, Timothy/C-8164-2012; Golenetskii, Sergey/B-3818-2015; OI Feroci, Marco/0000-0002-7617-3421; Boer, Michel/0000-0001-9157-4349 NR 14 TC 1 Z9 1 U1 0 U2 0 PU SOCIETA ITALIANA DI FISICA PI BOLOGNA PA VIA SARAGOZZA, 12, I-40123 BOLOGNA, ITALY SN 1124-1896 J9 NUOVO CIMENTO C JI Nuovo Cimento Soc. Ital. Fis. C-Geophys. Space Phys. PD MAY-JUN PY 2005 VL 28 IS 3 BP 299 EP 302 DI 10.1393/ncc/i2005-10044-2 PG 4 GA 989AT UT WOS:000233646000013 ER PT J AU Sakamoto, T Lamb, DQ Kawai, N Yoshida, A Graziani, C Fenimore, EE Donaghy, TQ Matsuoka, M Suzuki, M Ricker, G Atteia, JL Shirasaki, Y Tamagawa, T Torii, K Nakagawa, Y Galassi, M Doty, J Vanderspek, R Crew, GB Villasenor, J Butler, N Jernigan, JG Barraud, C Bore, M Dezalay, JP Olive, JF Hurley, K Woosley, SE Pizzichini, G AF Sakamoto, T Lamb, DQ Kawai, N Yoshida, A Graziani, C Fenimore, EE Donaghy, TQ Matsuoka, M Suzuki, M Ricker, G Atteia, JL Shirasaki, Y Tamagawa, T Torii, K Nakagawa, Y Galassi, M Doty, J Vanderspek, R Crew, GB Villasenor, J Butler, N Jernigan, JG Barraud, C Bore, M Dezalay, JP Olive, JF Hurley, K Woosley, SE Pizzichini, G CA HETE-2 Sci Team TI Global characteristics of X-ray flashes and X-ray rich GRBs observed by HETE-2 SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-GEOPHYSICS AND SPACE PHYSICS LA English DT Article; Proceedings Paper CT 4th Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 18-22, 2004 CL Rome, ITALY ID CATALOG; BURSTS AB We describe and discuss the global properties of 45 gamma-ray bursts (CRBs) observed by HETE-2 during the first three years of its mission, forcing on the properties of X-Ray Flashes (XRFs) and X-ray-rich GRBs (XRRs). We find that: 1) the numbers of XRFs, XRRs, and CRBs are comparable, 2) the durations of XRFs and XRRs are similar to those of GRBs, and 3) the spectral properties of XRFs and XRRs are similar to those of GRBs, expect that the values of the peak energy E-peak of the burst spectrum is vF(v), the peak flux F, and the fluence S of XRFs are much smaller -and those of XRRs are smaller- than those of GRBs. These results provide strong evidence that all three kinds of bursts arise from the same phenomenon. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Chicago, Chicago, IL 60637 USA. Tokyo Inst Technol, Meguro Ku, Tokyo 1528551, Japan. Aoyama Gakuin Univ, Setagaya Ku, Tokyo 1578572, Japan. Natl Astron Observ, Mitaka, Tokyo 1818588, Japan. RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Osaka Univ, Toyonaka, Osaka 5600043, Japan. Japan Aerosp Explorat Agcy, JAXA, Tsukuba, Ibaraki 3058505, Japan. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. CNRS, UPS, F-31028 Toulouse, France. MIT, Cambridge, MA 02139 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. IASF, INAF, Sez Bologna, I-40129 Bologna, Italy. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. RP Sakamoto, T (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SOCIETA ITALIANA DI FISICA PI BOLOGNA PA VIA SARAGOZZA, 12, I-40123 BOLOGNA, ITALY SN 1124-1896 J9 NUOVO CIMENTO C JI Nuovo Cimento Soc. Ital. Fis. C-Geophys. Space Phys. PD MAY-JUN PY 2005 VL 28 IS 3 BP 339 EP 342 PG 4 GA 989AT UT WOS:000233646000023 ER PT J AU Sato, R Sakamoto, T Kawai, N Yoshida, A Matsuoka, M Shirasaki, Y Tamagawa, T Suzuki, M Nakagawa, Y Ricker, GR Lamb, DQ Atteia, JL Graziani, C Vanderspek, R Crew, GB Villasenor, J Fenimore, EE AF Sato, R Sakamoto, T Kawai, N Yoshida, A Matsuoka, M Shirasaki, Y Tamagawa, T Suzuki, M Nakagawa, Y Ricker, GR Lamb, DQ Atteia, JL Graziani, C Vanderspek, R Crew, GB Villasenor, J Fenimore, EE CA HETE-2 Sci Team TI HETE-2 localization and observation of the gamma-ray burst GRB 020813 SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-GEOPHYSICS AND SPACE PHYSICS LA English DT Article; Proceedings Paper CT 4th Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 18-22, 2004 CL Rome, ITALY AB A bright, long gamma-ray burst (GRB) was detected and localized by the instruments on board the High Energy Transient Explorer 2 satellite (HETEL-2) at 02:44:19.17 UTC (9859.17 s UT) on 2002 August 13. The location was to the GRB Coordinates Network (GCN) about 4 minutes after the burst allowing, early observations of a counterpart in the optical. In the prompt emission, the burst had a duration of approximately 125s, and more than four peaks. We analyzed the time-resolved energy spectrum of the prompt emission of GRB020813 using the Wide Field X-ray Monitor (WXM) and the French Gamma Telescope (FREGATE) in 2-400keV in detail. We find that the former part of the burst shows extremely hard X-ray spectrum. C1 Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 152, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RIKEN, Wako, Saitama 35101, Japan. Aoyama Gakuin Univ, Dept Phys, Sagamihara, Kanagawa, Japan. JAXA, Tsukuba, Ibaraki, Japan. Natl Astron Observ, Mitaka, Tokyo, Japan. Osaka Univ, Dept Phys, Toyonaka, Osaka 560, Japan. MIT, CSR, Cambridge, MA 02139 USA. Univ Chicago, Dept Astron, Chicago, IL 60637 USA. Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France. Los Alamos Natl Lab, Los Alamos, NM USA. RP Sato, R (reprint author), Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 152, Japan. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SOCIETA ITALIANA DI FISICA PI BOLOGNA PA VIA SARAGOZZA, 12, I-40123 BOLOGNA, ITALY SN 1124-1896 J9 NUOVO CIMENTO C JI Nuovo Cimento Soc. Ital. Fis. C-Geophys. Space Phys. PD MAY-JUN PY 2005 VL 28 IS 3 BP 343 EP 346 DI 10.1393/ncc/i2005-10056-x PG 4 GA 989AT UT WOS:000233646000024 ER PT J AU Nishikawa, KI Hardee, P Hededal, CB Richardson, G Sol, H Preece, R Fishman, GJ AF Nishikawa, KI Hardee, P Hededal, CB Richardson, G Sol, H Preece, R Fishman, GJ TI Particle acceleration, magnetic field generation, and emission in relativistic pair jets SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA C-GEOPHYSICS AND SPACE PHYSICS LA English DT Article; Proceedings Paper CT 4th Workshop on Gamma-Ray Bursts in the Afterglow Era CY OCT 18-22, 2004 CL Rome, ITALY ID SHOCKS; PLASMA AB Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating into an ambient plasma. We find that the growth times of Weibel instability are proportional to the Lorentz factors of jets. Simulations show that the Weibel instability created in the collisionless shock front accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction. The small-scale magnetic field structure generated by the Weibel instability is appropriate to the generation of "jitter" radiation from deflected electrons (positrons) as opposed to synchrotron radiation. The jitter radiation resulting from small scale magnetic field structures may be important for understanding the complex time structure and spectral evolution observed in gamma-ray bursts or other astrophysical sources containing relativistic jets and relativistic collisionless shocks. C1 Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. Niels Bohr Inst, Dept Astrophys, DK-2100 Copenhagen, Denmark. Univ Alabama, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA. LUTH, Observ Paris, F-92195 Meudon, France. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Natl Space Sci & Technol Ctr, NASA, Marshall Space Flight Ctr, Huntsville, AL 35805 USA. RP Nishikawa, KI (reprint author), Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. OI Preece, Robert/0000-0003-1626-7335 NR 9 TC 0 Z9 1 U1 0 U2 1 PU SOCIETA ITALIANA DI FISICA PI BOLOGNA PA VIA SARAGOZZA, 12, I-40123 BOLOGNA, ITALY SN 1124-1896 J9 NUOVO CIMENTO C JI Nuovo Cimento Soc. Ital. Fis. C-Geophys. Space Phys. PD MAY-JUN PY 2005 VL 28 IS 3 BP 435 EP 438 DI 10.1393/ncc/i2005-10077-5 PG 4 GA 989AT UT WOS:000233646000043 ER PT J AU Hegazy, MS Refaat, TF Abedin, MN Elsayed-Ali, HE AF Hegazy, MS Refaat, TF Abedin, MN Elsayed-Ali, HE TI Fabrication of Ge/Si quantum-dot infrared photodetector by pulsed laser deposition SO OPTICAL ENGINEERING LA English DT Article DE pulsed laser deposition; quantum dots; infrared; detectors ID SI/GE NANOSTRUCTURES; SI; PHOTOLUMINESCENCE AB A multilayered infrared Ge/Si quantum-dot photodetector is fabricated by pulsed laser deposition. Forty successive Ge quantum dot layers, each covered with a thin Si layer, are deposited. Deposition is monitored by in situ reflection high-energy electron diffraction and the morphology is further studied by ex situ atomic force microscopy. Current-voltage measurements reveal typical diode characteristics, while responsivity measurements show an absorption peak around a 2-mu m wavelength. C1 Old Dominion Univ, Dept Elect & Comp Engn, Phys Electron Res Inst, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Laser & Electroopt Branch, Hampton, VA 23681 USA. Old Dominion Univ, Phys Elect Res Inst, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. RP Old Dominion Univ, Dept Elect & Comp Engn, Phys Electron Res Inst, Norfolk, VA 23529 USA. EM helsayed@odu.edu NR 12 TC 5 Z9 5 U1 1 U2 7 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD MAY PY 2005 VL 44 IS 5 AR 059702 DI 10.1117/1.1907563 PG 3 WC Optics SC Optics GA 974KP UT WOS:000232590600046 ER PT J AU Wright, MW Franzen, D Hemmati, H Becker, H Sandor, M AF Wright, MW Franzen, D Hemmati, H Becker, H Sandor, M TI Qualification and reliability testing of a commercial high-power fiber-coupled semiconductor laser for space applications SO OPTICAL ENGINEERING LA English DT Article DE semiconductor laser; space qualification; reliability; testing AB A compact microchip laser pumped by a single fiber-coupled semiconductor diode laser is developed for a space-borne scanning laser radar instrument. A commercial off-the-shelf component is used for the pump laser and undergoes a rigorous qualification approach to meet the requirements for the space-borne application. The qualification and testing process for the commercial pump laser is derived based on a nonstandard piece part screening plan and is presented along with the test results. These tests include mechanical, vibration, thermal cycling, and radiation tests as well as a full destructive parts analysis. Accelerated lifetests are also performed on the packaged device to demonstrate the ability to meet an operational lifetime of 5000 h. The environmental testing approach would be applicable to space qualification of a variety of commercial photonic systems, particularly in cost-constrained missions. (c) 2005 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wright, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 3 Z9 3 U1 2 U2 9 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAY PY 2005 VL 44 IS 5 AR 054204 DI 10.1117/1.1902993 PG 8 WC Optics SC Optics GA 974KP UT WOS:000232590600024 ER PT J AU Wu, F Guo, SP IKram, K Albin, S Tai, H Rogowski, RS AF Wu, F Guo, SP IKram, K Albin, S Tai, H Rogowski, RS TI Numerical analysis of Bragg fibers using a compact 1D finite-difference frequency-domain method SO OPTICS COMMUNICATIONS LA English DT Article DE finite-difference frequency-domain method; Bragg fiber; eigenvalue problem ID PERFECTLY MATCHED LAYER; OPTICAL WAVE-GUIDES; BOUNDARY-CONDITION; PHOTONIC CRYSTAL; PROPAGATION; AIR; ALGORITHM; GUIDANCE; LIGHT AB A simple full vectorial finite-difference frequency-domain method is presented for dispersion and loss analysis of Bragg fibers. In both axial and azimuthal directions, the derivatives of the Maxwell's equations are calculated analytically, and the solution of Maxwell's equations is reduced to a 1D eigenvalue problem. Standard step-index and graded-index fibers with parabolic-index cores are analyzed to verify the validity of this method to round symmetric fibers with arbitrary index profiles. Numerical results on the mode propagation characteristics of Bragg fibers are found to agree very well with those obtained by transfer matrix method and Chew's method. (c) 2005 Elsevier B.V. All rights reserved. C1 Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Non Destruct Evaluat Sci Branch, Hampton, VA 23681 USA. RP Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Hampton Blvd, Norfolk, VA 23529 USA. EM fwu@odu.edu NR 28 TC 13 Z9 17 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 EI 1873-0310 J9 OPT COMMUN JI Opt. Commun. PD MAY 1 PY 2005 VL 249 IS 1-3 BP 165 EP 174 DI 10.1016/j.optcom.2005.01.008 PG 10 WC Optics SC Optics GA 920RE UT WOS:000228707000019 ER PT J AU Matta, JL Ramos, JM Armstrong, RA D'Antoni, H AF Matta, JL Ramos, JM Armstrong, RA D'Antoni, H TI Environmental UV-A and UV-B threshold doses for apoptosis and necrosis in human fibroblasts SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SOLAR-SIMULATING RADIATION; SKIN-CANCER; DNA-REPAIR; ULTRAVIOLET-RADIATION; CUTANEOUS MELANOMA; P53; EXPRESSION; IRRADIATION; INDUCTION; EXPOSURE AB Apoptosis involves a highly organized and programmed series of events aimed at maintaining genomic stability by eliminating defective host cells. The purpose of this study was to determine the threshold doses and environmental UV-A and UV-B exposure times necessary to produce apoptosis and necrosis in the normal cells of a human fibroblast cell line. Environmental UV-A and UV-B doses were measured over a 6 year period with a four-channel UV radiometer. The fibroblasts were irradiated once using an Oriel UV Solar Simulator with six doses of environmentally-based UV. Doses corresponded to 0, 11, 19, 23 and 45 min of average environmental UV-A and UV-B radiation at solar noon in Puerto Rico. The Annexin-V binding method was used to differentiate between normal fibroblasts and apoptotic or necrotic fibroblasts. The threshold dose from apoptosis to necrosis was found between 24-28 kJ/m(2), which corresponded to 19 and 23 min of environmental UV-A and UV-B exposure. This study provides the first data that specify the environmental threshold doses of UV-A and UV-B at which human fibroblasts undergo apoptosis and necrosis. These results may provide valuable dose-response thresholds for apoptosis and necrosis for future mechanistic studies and baseline data for skin cancer prevention programs. C1 Ponce Sch Med, Dept Pharmacol & Toxicol, Ponce, PR 00731 USA. Univ Puerto Rico, Dept Marine Sci, Mayaguez, PR 00709 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Matta, JL (reprint author), Ponce Sch Med, Dept Pharmacol & Toxicol, Ponce, PR 00731 USA. EM jmatta@psm.edu NR 47 TC 7 Z9 8 U1 0 U2 3 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD MAY-JUN PY 2005 VL 81 IS 3 BP 563 EP 568 DI 10.1562/2004-07-06-RA-224.1 PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 935CP UT WOS:000229757200016 ER PT J AU Boulatov, A Smelyanskiy, VN AF Boulatov, A Smelyanskiy, VN TI Random matrix approach to quantum adiabatic evolution algorithms SO PHYSICAL REVIEW A LA English DT Article ID ENERGY-LEVELS; STATISTICAL THEORY; COMPLEX SYSTEMS; EIGENVALUES; DISSIPATION AB We analyze the power of the quantum adiabatic evolution algorithm (QAA) for solving random computationally hard optimization problems within a theoretical framework based on random matrix theory (RMT). We present two types of driven RMT models. In the first model, the driving Hamiltonian is represented by Brownian motion in the matrix space. We use the Brownian motion model to obtain a description of multiple avoided crossing phenomena. We show that nonadiabatic corrections in the QAA are due to the interaction of the ground state with the "cloud" formed by most of the excited states, confirming that in driven RMT models, the Landau-Zener scenario of pairwise level repulsions is not relevant for the description of nonadiabatic corrections. We show that the QAA has a finite probability of success in a certain range of parameters, implying a polynomial complexity of the algorithm. The second model corresponds to the standard QAA with the problem Hamiltonian taken from the RMT Gaussian unitary ensemble (GUE). We show that the level dynamics in this model can be mapped onto the dynamics in the Brownian motion model. For this reason, the driven GUE model can also lead to polynomial complexity of the QAA. The main contribution to the failure probability of the QAA comes from the nonadiabatic corrections to the eigenstates, which only depend on the absolute values of the transition amplitudes. Due to the mapping between the two models, these absolute values are the same in both cases. Our results indicate that this "phase irrelevance" is the leading effect that can make both the Markovian- and GUE-type QAAs successful. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 269-3, Moffett Field, CA 94035 USA. RI Boulatov, Alexei/A-7096-2014 NR 28 TC 3 Z9 3 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2005 VL 71 IS 5 AR 052309 DI 10.1103/PhysRevA.71.052309 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 932HA UT WOS:000229543600023 ER PT J AU Mitchell, DR Adami, C Lue, W Williams, CP AF Mitchell, DR Adami, C Lue, W Williams, CP TI Random matrix model of adiabatic quantum computing SO PHYSICAL REVIEW A LA English DT Article ID LANDAU-ZENER TRANSITIONS; ENERGY-LEVELS; DISSIPATION; SYSTEMS; PHYSICS; SPECTRA AB We present an analysis of the quantum adiabatic algorithm for solving hard instances of 3-SAT (an NP-complete problem) in terms of random matrix theory (RMT). We determine the global regularity of the spectral fluctuations of the instantaneous Hamiltonians encountered during the interpolation between the starting Hamiltonians and the ones whose ground states encode the solutions to the computational problems of interest. At each interpolation point, we quantify the degree of regularity of the average spectral distribution via its Brody parameter, a measure that distinguishes regular (i.e., Poissonian) from chaotic (i.e., Wigner-type) distributions of normalized nearest-neighbor spacings. We find that for hard problem instances-i.e., those having a critical ratio of clauses to variables-the spectral fluctuations typically become irregular across a contiguous region of the interpolation parameter, while the spectrum is regular for easy instances. Within the hard region, RMT may be applied to obtain a mathematical model of the probability of avoided level crossings and concomitant failure rate of the adiabatic algorithm due to nonadiabatic Landau-Zener-type transitions. Our model predicts that if the interpolation is performed at a uniform rate, the average failure rate of the quantum adiabatic algorithm, when averaged over hard problem instances, scales exponentially with increasing problem size. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NW State Univ, Natchitoches, LA 71497 USA. Stanford Univ, Stanford, CA 94305 USA. Keck Grad Inst, Claremont, CA 91711 USA. RP CALTECH, Jet Prop Lab, MS 126-347, Pasadena, CA 91109 USA. RI Adami, Christoph/A-5181-2009; Adami, Christoph/A-9675-2011 OI Adami, Christoph/0000-0002-2915-9504 NR 28 TC 5 Z9 5 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2005 VL 71 IS 5 AR 052324 DI 10.1103/PhysRevA.71.052324 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 932HA UT WOS:000229543600038 ER PT J AU Bauschlicher, CW Ricca, A AF Bauschlicher, CW Ricca, A TI Rotational barriers of a nitrophenylene ethynylene trimer SO PHYSICAL REVIEW B LA English DT Article ID NEGATIVE DIFFERENTIAL RESISTANCE; MONOLAYERS AB The rotational barriers for a nitrophenylene ethynylene trimer have been computed using density-functional theory. The local minima previously reported and used to explain the negative differential resistance, (NDR) for this class of molecules appear to be an artifact due to basis set superposition error. While there is a local minimum for highly tilted molecules, the tilt angle required to produce the correct barrier height is at the upper limit of the reported experimental values. We believe that it is premature to explain the experimentally observed NDR in terms of a rotational barrier of a monolayer with a parallel slipped commensurate structure. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAY PY 2005 VL 71 IS 20 AR 205406 DI 10.1103/PhysRevB.71.205406 PG 6 WC Physics, Condensed Matter SC Physics GA 941WG UT WOS:000230244300084 ER PT J AU Pullen, A Zhao, GL Bagayoko, B Yang, L AF Pullen, A Zhao, GL Bagayoko, B Yang, L TI Structural, elastic, and electronic properties of deformed carbon nanotubes under uniaxial strain SO PHYSICAL REVIEW B LA English DT Article ID DENSITY-OF-STATES; AB-INITIO; TORSIONAL STRAIN; APPROXIMATION; ENERGY; CONSTANTS; GRAPHITE; GAS AB We report structural, elastic, and electronic properties of selected, deformed, single-wall carbon nanotubes under uniaxial strain. We utilized a generalized gradient approximation potential of density functional theory and the linear combination of atomic orbital formalism. We discuss bond-lengths, tubule radii, and the band gaps as functions of tension and compression strain for carbon nanotubes (10, 0), (8, 4), and (10, 10) which have chiral angles of 0, 19.1, and 30 deg relative to the zigzag direction. We also calculated the Young's modulus and the in-plane stiffness for each of these three nanotubes as representatives of zigzag, chiral, and armchair nanotubes, respectively. We found that these carbon nanotubes have unique structural properties consisting of a strong tendency to retain their tubule radii under large tension and compression strains. C1 So Univ & A&M Coll, Dept Phys, Baton Rouge, LA 70813 USA. NASA Ames Res Ctr, Moffett Field, CA 94035 USA. RP So Univ & A&M Coll, Dept Phys, Baton Rouge, LA 70813 USA. EM zhao@grant.phys.subr.edu RI Pullen, Anthony/I-7007-2015 OI Pullen, Anthony/0000-0002-2091-8738 NR 36 TC 27 Z9 27 U1 1 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY PY 2005 VL 71 IS 20 AR 205410 DI 10.1103/PhysRevB.71.205410 PG 5 WC Physics, Condensed Matter SC Physics GA 941WG UT WOS:000230244300088 ER PT J AU Chu, M Eriksen, HK Knox, L Gorski, KM Jewell, JB Larson, DL O'Dwyer, IJ Wandelt, BD AF Chu, M Eriksen, HK Knox, L Gorski, KM Jewell, JB Larson, DL O'Dwyer, IJ Wandelt, BD TI Cosmological parameter constraints as derived from the Wilkinson Microwave Anisotropy Probe data via Gibbs sampling and the Blackwell-Rao estimator SO PHYSICAL REVIEW D LA English DT Article ID COSMIC BACKGROUND IMAGER; ANGULAR POWER SPECTRUM; WMAP OBSERVATIONS; MOSAIC OBSERVATIONS; MAPS; ACBAR AB We study the Blackwell-Rao (BR) estimator of the probability distribution of the angular power spectrum, P(C(l)parallel to d), by applying it to samples of full-sky no-noise CMB maps generated via Gibbs sampling. We find the estimator, given a set of samples, to be very fast and also highly accurate, as determined by tests with simulated data. We also find that the number of samples required for convergence of the BR estimate rises rapidly with increasing l, at least at low l. Our existing sample chains are only long enough to achieve convergence at l less than or similar to 40. In comparison with P(C-l vertical bar d) as reported by the WMAP team we find significant differences at these low center dot values. These differences lead to up to similar to 0.5 sigma shifts in the estimates of parameters in a 7-parameter Lambda CDM model with nonzero dn(s)/d lnk. Fixing dn(s)/d lnk = 0 makes these shifts much less significant. Unlike existing analytic approximations, the BR estimator can be straightforwardly extended for the case of power spectra from correlated fields, such as temperature and polarization. We discuss challenges to extending the procedure to higher l and provide some solutions. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Oslo, Ctr Math Applicat, N-0316 Oslo, Norway. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Chu, M (reprint author), Univ Calif Davis, Dept Phys, 1 Shields Ave, Davis, CA 95616 USA. EM mchu@bubba.physics.ucdavis.edu; h.k.k.eriksen@astro.uio.no; knox@bubba.physics.ucdavis.edu NR 30 TC 31 Z9 31 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2005 VL 71 IS 10 AR 103002 DI 10.1103/PhysRevD.71.103002 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 930TQ UT WOS:000229440400004 ER PT J AU Fiske, DR Baker, JG van Meter, JR Choi, DI Centrella, JM AF Fiske, DR Baker, JG van Meter, JR Choi, DI Centrella, JM TI Wave zone extraction of gravitational radiation in three-dimensional numerical relativity SO PHYSICAL REVIEW D LA English DT Article ID ADAPTIVE MESH; BLACK-HOLES; EVOLUTION AB We present convergent gravitational waveforms extracted from three-dimensional, numerical simulations in the wave zone and with causally disconnected boundaries. These waveforms last for multiple periods and are very accurate, showing a peak error to peak amplitude ratio of 2% or better. Our approach includes defining the Weyl scalar Psi(4) in terms of a three-plus-one decomposition of the Einstein equations; applying, for the first time, a novel algorithm due to Misner for computing spherical harmonic components of our wave data; and using fixed mesh refinement to focus resolution on nonlinear sources while simultaneously resolving the wave zone and maintaining a causally disconnected computational boundary. We apply our techniques to a (linear) Teukolsky wave, and then to an equal-mass, head-on collision of two black holes. We argue both for the quality of our results and for the value of these problems as standard test cases for wave extraction techniques. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Lab Gravitat Astrophys, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RI van meter, james/E-7893-2011 NR 31 TC 36 Z9 36 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2005 VL 71 IS 10 AR 104036 DI 10.1103/PhysRevD.71.104036 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 930TQ UT WOS:000229440400072 ER PT J AU Miller, M AF Miller, M TI Accuracy requirements for the calculation of gravitational waveforms from coalescing compact binaries in numerical relativity SO PHYSICAL REVIEW D LA English DT Article ID RADIATION REACTION; EQUATIONS; SYSTEMS AB I discuss the accuracy requirements on numerical relativity calculations of inspiraling compact object binaries whose extracted gravitational waveforms are to be used as templates for matched filtering signal extraction and physical parameter estimation in modern interferometric gravitational wave detectors. Using a post-Newtonian point particle model for the premerger phase of the binary inspiral, I calculate the maximum allowable errors for the mass and relative velocity and positions of the binary during numerical simulations of the binary inspiral. These maximum allowable errors are compared to the errors of state-of-the-art numerical simulations of multiple-orbit binary neutron star calculations in full general relativity, and are found to be smaller by several orders of magnitude. A post-Newtonian model for the error of these numerical simulations suggests that adaptive mesh refinement coupled with second-order accurate finite difference codes will not be able to robustly obtain the accuracy required for reliable gravitational wave extraction on Terabyte-scale computers. I conclude that higher-order methods (higher-order finite difference methods and/or spectral methods) combined with adaptive mesh refinement and/or multipatch technology will be needed for robustly accurate gravitational wave extraction from numerical relativity calculations of binary coalescence scenarios. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Miller, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD MAY PY 2005 VL 71 IS 10 AR 104016 DI 10.1103/PhysRevD.71.104016 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 930TQ UT WOS:000229440400052 ER PT J AU Balasubramaniam, R Rashidnia, N Maxworthy, T Kuang, J AF Balasubramaniam, R Rashidnia, N Maxworthy, T Kuang, J TI Instability of miscible interfaces in a cylindrical tube SO PHYSICS OF FLUIDS LA English DT Article ID CORE-ANNULAR-FLOW; CAPILLARY TUBES; DISPLACEMENTS; FLUIDS; VISCOSITY; STRATIFICATION; STABILITY; PIPE AB We report experimental results on the displacement of a less viscous liquid by a more viscous, miscible liquid in a vertical tube of small diameter. The liquids used are silicone oils of various viscosities. The more viscous fluid has a higher density than the less viscous fluid. Both upward displacement and downward displacement have been studied. Our observations show that for downward displacement, the "interface" between the liquids can be unstable and exhibits an asymmetric, sinuous shape. During upward displacement, the interface forms an axisymmetric finger of the intruding liquid. At the tip of the main finger, a spike of the more viscous liquid is observed under some conditions. The Reynolds number is negligibly small in these experiments and the Peclet number for mass transfer is O(50)-O(10(5)). The influence of gravity is characterized by the dimensionless parameter F=g Delta rho d(2)/mu U where g is the acceleration due to gravity, Delta rho is the density difference between the fluids, Delta rho is the tube diameter, mu is the viscosity of the more viscous fluid, and U is the displacement speed. A plot of F versus the viscosity ratio of the fluids is constructed to delineate the stable and unstable regimes of flow. (c) 2005 American Institute of Physics. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. Univ So Calif, Los Angeles, CA 90089 USA. RP Balasubramaniam, R (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. NR 17 TC 26 Z9 26 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 2005 VL 17 IS 5 AR 052103 DI 10.1063/1.1884645 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 925SN UT WOS:000229073700007 ER PT J AU Podesta, JJ AF Podesta, JJ TI Spatial Landau damping in plasmas with three-dimensional kappa distributions SO PHYSICS OF PLASMAS LA English DT Article ID DISPERSION FUNCTION; SPACE PLASMAS; LORENTZIAN DISTRIBUTION; ELECTRONS; ION; WAVES AB The increase in linear Landau damping in kappa-distributed plasmas compared to thermal equilibrium plasmas is studied by solving a boundary value problem for the spatially damped plasma waves generated by a planar grid electrode with an applied time harmonic potential. Solutions are computed for the plasma potential versus the distance from the electrode for different values of the parameter kappa skappad. The velocity parameter v(0) of the distribution function is chosen so that, as the parameter kappa varies, the kinetic temperature of the plasma remains constant. The exact solutions of this problem are also compared to approximate solutions derived from the theory of normal modes, that is, from the roots of the dispersion relation. This model problem demonstrates the significant increase in Landau damping by electrons which occurs for small values of the parameter kappa. (c) 2005 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Code 612-2, Greenbelt, MD 20771 USA. EM jpodesta@solar.stanford.edu NR 26 TC 25 Z9 25 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 2005 VL 12 IS 5 AR 052101 DI 10.1063/1.1885474 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 928MQ UT WOS:000229276200004 ER PT J AU Stefanovic, I Kovacevic, E Berndt, J Pendleton, Y Winter, J AF Stefanovic, I Kovacevic, E Berndt, J Pendleton, Y Winter, J TI Hydrocarbon nanoparticles as a diffuse ISM analogue: morphology and infrared absorption in the 2000-500 cm(-1) region SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT 12th International Congress on Plasma Physics (ICPP2004) CY OCT 25-29, 2004 CL Nice, FRANCE SP Int Advisory Comm ID INTERSTELLAR-MEDIUM; C-H; MICRON SPECTROSCOPY; GALACTIC-CENTER; DUST; EMISSION; GRAINS; BAND; CONSTRAINTS; GALAXIES AB In this paper, we analyse the morphology and chemistry of carbonaceous dust particles previously proposed as a candidate analogue material for dust in the diffuse interstellar medium (ISM). The particles were polymerized in a low pressure capacitively coupled radiofrequency discharge in mixtures of argon/acetylene and helium/acetylene. Infrared (IR) spectra of our dust particles reveal the strong presence of aliphatic features, both stretching and bending modes, which are very similar to astronomical data from diffuse interstellar dust. A comparison between the IR spectra obtained using argon or helium as buffer gases reveals the strong presence of C=C double bonds (skeletal modes) when helium is used. The presence of these skeletal modes is clearly visible through the broad absorption feature at 1600 cm(-1) (6.25 mu m). The origin of this feature in our laboratory analogue is related to the change in the plasma parameters due to the variation of the buffer gas used under the same discharge conditions. Observational data of interstellar polycyclic aromatic hydrocarbons also exhibit a feature at this wavelength. C1 Ruhr Univ Bochum, Inst Expt Phys 2, D-44780 Bochum, Germany. Inst Phys, Belgrade 11001, Serbia Monteneg. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ruhr Univ Bochum, Inst Expt Phys 2, D-44780 Bochum, Germany. RI Stefanovic, Ilija/F-5444-2010 OI Stefanovic, Ilija/0000-0002-1652-1287 NR 44 TC 19 Z9 19 U1 1 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 2005 VL 47 SU 5A SI SI BP A179 EP A189 DI 10.1088/0741-3335/47/5A/013 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 932YQ UT WOS:000229591100014 ER PT J AU Kok, P Ralph, TC Milburn, GJ AF Kok, P Ralph, TC Milburn, GJ TI Communicating continuous quantum variables between different Lorentz frames SO QUANTUM INFORMATION & COMPUTATION LA English DT Article DE quantum communication; relativistic information theory ID ERROR-CORRECTION; ENTANGLEMENT AB We show how to communicate Heisenberg-limited continuous (quantum) variables between Alice and Bob in the case where they occupy two inertial reference frames that differ by an unknown Lorentz boost. There are two effects that need to be overcome: the Doppler shift and the absence of synchronized clocks. Furthermore, we show how Alice and Bob can share Doppler-invariant entanglement, and we demonstrate that the protocol is robust under photon loss. C1 Hewlett Packard Labs, Bristol BS34 8QZ, Avon, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Queensland, Dept Phys, Ctr Quantum Comp Technol, St Lucia, Qld 4072, Australia. RP Kok, P (reprint author), Hewlett Packard Labs, Filton Rd, Bristol BS34 8QZ, Avon, England. RI MIlburn, Gerard/B-6381-2008; Kok, Pieter/B-1658-2010; Ralph, Timothy/A-1858-2011 OI MIlburn, Gerard/0000-0002-5404-9681; NR 20 TC 7 Z9 7 U1 0 U2 0 PU RINTON PRESS, INC PI PARAMUS PA 565 EDMUND TERRACE, PARAMUS, NJ 07652 USA SN 1533-7146 J9 QUANTUM INFORM COMPU JI Quantum Inform. Comput. PD MAY PY 2005 VL 5 IS 3 BP 239 EP 246 PG 8 WC Computer Science, Theory & Methods; Physics, Particles & Fields; Physics, Mathematical SC Computer Science; Physics GA 939YP UT WOS:000230109100004 ER PT J AU Pederson, DC Peteet, DM Kurdyla, D Guilderson, T AF Pederson, DC Peteet, DM Kurdyla, D Guilderson, T TI Medieval Warming, Little Ice Age, and European impact on the environment during the last millennium in the lower Hudson Valley, New York, USA SO QUATERNARY RESEARCH LA English DT Article DE pollen; charcoal; climate; Medieval Warming; Little Ice Age; land use; Hudson Valley; Phragmites; Typha ID ESTUARINE SEDIMENT ACCUMULATION; NEW-ENGLAND; CHESAPEAKE BAY; UNITED-STATES; TIDAL MARSH; SOUTHERN CONNECTICUT; HOLOCENE VEGETATION; NORTH-AMERICA; NEW-JERSEY; CLIMATE AB Establishing natural climate variability becomes particularly important in large urban areas in anticipation of droughts. We present a welldated bi-decadal record of vegetation, climate, land use, and fire frequency from a tidal marsh in the Hudson River Estuary. The classic Medieval Warm Period is evident through striking increases in charcoal and Pinus dominance from &SIM; 800-1300 A.D., paralleling paleorecords southward along the Atlantic seaboard. Higher inputs of inorganic sediment during this interval suggest increased watershed erosion during drought conditions. The presence of the Little Ice Age ensues with increases in Picea and Tsuga, coupled with increasing organic percentages due to cooler, moister conditions. European impact is manifested by a decline in arboreal pollen due to land clearance, increased weedy plant cover (i.e., Ambrosia, Plantago, and Rumex), and an increase in inorganic particles to the watershed. © 2005 University of Washington. All rights reserved. C1 Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. RP Pederson, DC (reprint author), Lamont Doherty Earth Observ, 61 Rte 9W, Palisades, NY 10964 USA. EM dcp@ldeo.columbia.edu NR 76 TC 70 Z9 72 U1 3 U2 24 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0033-5894 J9 QUATERNARY RES JI Quat. Res. PD MAY PY 2005 VL 63 IS 3 BP 238 EP 249 DI 10.1016/j.yqres.2005.01.001 PG 12 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 923ZE UT WOS:000228947300003 ER PT J AU Schmidt, GA LeGrande, AN AF Schmidt, GA LeGrande, AN TI The Goldilocks abrupt climate change event SO QUATERNARY SCIENCE REVIEWS LA English DT Editorial Material ID OCEAN MODEL C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. RP Schmidt, GA (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gschmidt@giss.nasa.gov RI Schmidt, Gavin/D-4427-2012; LeGrande, Allegra/D-8920-2012 OI Schmidt, Gavin/0000-0002-2258-0486; LeGrande, Allegra/0000-0002-5295-0062 NR 3 TC 11 Z9 11 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0277-3791 J9 QUATERNARY SCI REV JI Quat. Sci. Rev. PD MAY PY 2005 VL 24 IS 10-11 BP 1109 EP 1110 DI 10.1016/j.quascirev.2005.01.015 PG 2 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 914WC UT WOS:000228257700001 ER PT J AU Sarma, GR Moes, TR AF Sarma, GR Moes, TR TI Demonstration of skin friction measurements featuring in situ estimation of conduction loss using constant voltage anemometers and surface hot-films SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID OVERHEAT; FLOWS; WIRE AB The top of the 12.2 m long NASA Dryden Flight Research Center's ground research vehicle (GRV) was used as a flat plate test bed for demonstrating an approach to measure skin friction. Using an array of surface hot-films operated by constant voltage anemometers (CVAs), the approach was demonstrated with in situ estimation of conduction heat loss from the hot-films to the substrate. An algebraic relationship, using the channel calibration constants a and b (determined a priori) with CVA output voltages V-s and V-w from that channel, is used for the estimation of the required quantities and lead resistance (r(L)) of the hot-film measured on site. Estimates of the power dissipated in the hot-film alone (P-hf) (excluding the lead resistances), in situ resistance (R-w) of the hot-film due to applied overheat and flow, and the cold resistance (R-a) of the same hot-film at the ambient temperature are so obtained. Different approaches to estimate the in situ cold resistance (which is the resistance without any self-heating) of the hot-film are presented addressing the suitability of the procedure for flight applications as well. Tests were performed at several speeds of the GRV on the tarmac of a runway at the flight test center. The measured values are fitted to the classical (1/3) law equation with the computational dimensional skin friction (τ) obtained using the empirical local skin friction law for the long flat plate. There was an excellent (1/3) law fit in all the hot-films, demonstrating that the measured values fit classical theory. Using this measured fit with the theoretical values, calibration coefficients (A and B) for dimensional skin friction (τ) were obtained. Using these calibration coefficients, measured values were then converted to nondimensional local skin friction coefficients c(f) for all the hot-films at all speeds. Measured cf values agree well with the associated flat plate theory. Since the in situ measurement of heat loss to the substrate should ideally apply at all ambient temperatures, the method was tested in a wind tunnel at two ambient temperatures, where the results repeated well. Accounting for conduction loss had been the difficult issue in using hot-films, which otherwise offer many advantages. For example, skin friction from an array of hot-films can be measured simultaneously and the hot-films offer large dynamic response, high sensitivity, and simple installation. In practice, it should be possible to insert a calibrated plug in the test article and use the in situ measured substrate loss to accurately estimate the skin friction. The approach does not need any additional temperature sensor to accomplish the measurements. The system is highly amenable to automation with further work. It may be noted that the purpose of this test and article is to demonstrate an approach to skin friction measurements using hot-films operated by CVAs with in situ estimation of the heat loss to the substrate. It does not address any other aspect of the skin friction measurements. © 2005 American Institute of Physics. C1 Tao Syst Inc, Hampton, VA 23666 USA. NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93524 USA. RP Sarma, GR (reprint author), Tao Syst Inc, Hampton, VA 23666 USA. EM GARIMELLA9@aol.com; Timothy.R.Moes@nasa.gov NR 10 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 2005 VL 76 IS 5 AR 055102 DI 10.1063/1.1896621 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 925PF UT WOS:000229064300061 ER PT J AU Kharuk, VI Dvinskaya, ML Ranson, KJ Im, ST AF Kharuk, VI Dvinskaya, ML Ranson, KJ Im, ST TI Expansion of evergreen conifers to the larch-dominated zone and climatic trends SO RUSSIAN JOURNAL OF ECOLOGY LA English DT Article DE larch forests; successions; climatic trends; forest fire sites; permafrost AB The expansion of so-called evergreen conifers (EGCs), including Siberian stone pine, spruce, and fir, along the transect oriented from the boundary of the larch-dominated zone (LDZ; mixed forests of the Yenisei Ridge) to its center has been studied. The normalized dispersal coefficient calculated as K-i = (n(i) - N-i)/(n(i) + N-i), where ni and Ni are the relative numbers of the ith species in the undergrowth and the upper layer, respectively, serves as an indicator of the expansion. It has been found that the Ki values for EGCs (and birch) are higher than the Ki of larch even in the zone absolutely dominated by larch, where the relative numbers of EGCs in the upper layer is less than 1%. The EGC undergrowth has mainly been formed during the past 20-30 years, which is correlated with the trend of summer temperatures The spread of EGCs in the LDZ depends on the frequency of forest fires. The decrease in the time intervals between fires in the 20th century to 65 years (versus 100 years in the 19th century) may have prevented the expansion of competing species in the LDZ. The results obtained indicate that EGCs and birch penetrate into the zone traditionally dominated by larch, which is related to climatic changes during the past three decades. At the same time, tree stand density is increasing in the forest-tundra ecotone, and larch is spreading further into the tundra zone. C1 Russian Acad Sci, Siberian Div, Sukachev Inst Forest, Krasnoyarsk 660036, Russia. NASA, Goddard Space Ctr, Greenbelt, MD 20771 USA. RP Kharuk, VI (reprint author), Russian Acad Sci, Siberian Div, Sukachev Inst Forest, Krasnoyarsk 660036, Russia. RI Ranson, Kenneth/G-2446-2012; Im, Sergei/J-2736-2016 OI Ranson, Kenneth/0000-0003-3806-7270; Im, Sergei/0000-0002-5794-7938 NR 13 TC 32 Z9 33 U1 0 U2 8 PU MAIK NAUKA/INTERPERIODICA PI NEW YORK PA C/O KLUWER ACADEMIC-PLENUM PUBLISHERS, 233 SPRING ST, NEW YORK, NY 10013-1578 USA SN 1067-4136 J9 RUSS J ECOL+ JI Russ. J. Ecol. PD MAY-JUN PY 2005 VL 36 IS 3 BP 164 EP 170 DI 10.1007/s11184-005-0055-5 PG 7 WC Ecology SC Environmental Sciences & Ecology GA 931BK UT WOS:000229460600004 ER PT J AU Gunapala, SD Bandara, SV Liu, JK Hill, CJ Rafol, SB Mumolo, JM Trinh, JT Tidrow, MZ Le Van, PD AF Gunapala, SD Bandara, SV Liu, JK Hill, CJ Rafol, SB Mumolo, JM Trinh, JT Tidrow, MZ Le Van, PD TI 1024 x 1024 pixel mid-wavelength and long-wavelength infrared QWIP focal plane arrays for imaging applications SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Article ID NARROW-BAND; BROAD-BAND; CAMERA; DETECTORS AB Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 10(24) x 10(24) pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEAT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEAT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In this paper, we will discuss the performance in terms of quantum efficiency, NEAT, uniformity, operability and modulation transfer functions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Missile Def Agcy AS, Washington, DC 20301 USA. USAF, Kirtland Air Force Base, Kirtland AFB, NM 87117 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 69 Z9 79 U1 3 U2 13 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD MAY PY 2005 VL 20 IS 5 BP 473 EP 480 DI 10.1088/0268-1242/20/5/026 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 935QX UT WOS:000229797900029 ER PT J AU Beaubouef, T Petry, FE AF Beaubouef, T Petry, FE TI Representation of spatial data in an OODB using rough and fuzzy set modeling SO SOFT COMPUTING LA English DT Article DE spatial data; object-oriented database; rough sets; fuzzy sets; uncertainty ID INFORMATION-SYSTEMS; RELATIONAL DATABASE AB This paper introduces and formally defines a fuzzy rough object-oriented database (OODB) model based on a formal framework using an algebraic type system and formally defined constraints. This generalized model incorporates both rough set and fuzzy set uncertainty, while remaining compliant with object-oriented database standards set forth by the Object Database Management Group. Rough and fuzzy set uncertainty enhance the OODB model so that it can more accurately model real world applications. Spatial databases have a particular need for uncertainty management that can be achieved through rough and fuzzy techniques. C1 SE Louisiana Univ, Dept Comp Sci, Hammond, LA 70402 USA. USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. RP Beaubouef, T (reprint author), SE Louisiana Univ, Dept Comp Sci, Hammond, LA 70402 USA. EM tbeaubouef@selu.edu; fpetry@nrlssc.navy.mil RI Petry, Frederick/F-9894-2010 NR 37 TC 1 Z9 2 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 1432-7643 J9 SOFT COMPUT JI Soft Comput. PD MAY PY 2005 VL 9 IS 5 BP 364 EP 373 DI 10.1007/s00500-004-0416-1 PG 10 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA 924YZ UT WOS:000229018800007 ER PT J AU Reddi, LN Xiao, M Steinberg, SL AF Reddi, LN Xiao, M Steinberg, SL TI Discontinuous pore fluid distribution under microgravity - KC-135 flight investigations SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID SCALE AB Designing a reliable plant growth system for crop production in space requires the understanding of pore fluid distribution in porous media under microgravity. The objective of this experimental investigation, which was conducted aboard NASA KC-135 reduced gravity flight, is to study possible particle separation and the distribution of discontinuous wetting fluid in porous media under microgravity. KC-135 aircraft provided gravity conditions of 1, 1.8, and 10(-2) g. Glass beads of a known size distribution were used as porous media; and Hexadecane, a petroleum compound immiscible with and lighter than water, was used as wetting fluid at residual saturation. Nitrogen freezer was used to solidify the discontinuous Hexadecane ganglia in glass beads to preserve the ganglia size changes during different gravity conditions, so that the blob-size distributions (BSDs) could be measured after flight. It was concluded from this study that microgravity has little effect on the size distribution of pore fluid blobs corresponding to residual saturation of wetting fluids in porous media. The blobs showed no noticeable breakup or coalescence during microgravity. However, based on the increase in bulk volume of samples due to particle separation under microgravity, groups of particles, within which pore fluid blobs were encapsulated, appeared to have rearranged themselves under microgravity. C1 Kansas State Univ, Dept Civil Engn, Manhattan, KS 66506 USA. NASA, Lyndon B Johnson Space Ctr, Univ Space Res Assoc, Houston, TX 77058 USA. RP Reddi, LN (reprint author), Kansas State Univ, Dept Civil Engn, 2118 Fiedler Hall, Manhattan, KS 66506 USA. EM reddi@ksu.edu NR 10 TC 5 Z9 5 U1 0 U2 5 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAY-JUN PY 2005 VL 69 IS 3 BP 593 EP 598 DI 10.2136/sssaj.2004.0157 PG 6 WC Soil Science SC Agriculture GA 924VV UT WOS:000229009800003 PM 16052743 ER PT J AU Landi, BJ Castro, SL Ruf, HJ Evans, CM Bailey, SG Raffaelle, RP AF Landi, BJ Castro, SL Ruf, HJ Evans, CM Bailey, SG Raffaelle, RP TI CdSe quantum dot-single wall carbon nanotube complexes for polymeric solar cells SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article; Proceedings Paper CT International Conference on Physics, Chemistry and Engineering of Solar Cells CY MAY 13-15, 2004 CL Univ Extremadura, Sch Ind Engn, Badajoz, SPAIN HO Univ Extremadura, Sch Ind Engn DE polymer solar cell; quantum dot; carbon nanotube ID PI-CONJUGATED POLYMERS; PHOTOVOLTAIC DEVICES; EXCITON DISSOCIATION; NANOCRYSTALS; BLENDS; PHOTOCONDUCTIVITY; HETEROSTRUCTURES; SPECTROSCOPY; INTERFACE; DIFFUSION AB The development of lightweight, flexible polymeric solar cells which utilize nanostructured materials has been investigated. Incorporation of quantum dots (QDs) and single wall carbon nanotubes (SWNTs) into a poly(3-octylthiophene)-(P3OT) composite, has been shown to facilitate exciton dissociation and carrier transport in a properly structured device. Optimization towards an ideal electron acceptor for polymeric solar cells that exhibits high electron affinity and high electrical conductivity has been proposed in the form of QD-SWNT complexes. Specifically, the synthesis of CdSe-aminoethanethiol-SWNT complexes has been performed, with confirmation by microscopy (SEM, TEM, and AFM) and spectroscopy (FT-IR and optical absorption). Polymer composites containing these complexes in P3OT have been used to fabricate solar cells which show limited efficiency due to recombination and surface effects, but an open-circuit voltage (V-OC) of 0.75 V. However, evaluation of the optical absorption spectra for these nanomaterial-polymeric composites has shown a marked enhancement in the ability to capture the available irradiance of the air mass zero (AM0) spectrum. (c) 2004 Published by Elsevier B.V. C1 Rochester Inst Technol, NanoPower Res Labs, Rochester, NY 14623 USA. Ohio Aerosp Inst, Brookpark, OH 44142 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Raffaelle, RP (reprint author), Rochester Inst Technol, NanoPower Res Labs, Rochester, NY 14623 USA. EM rprsps@rit.edu NR 52 TC 154 Z9 155 U1 3 U2 54 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD MAY PY 2005 VL 87 IS 1-4 SI SI BP 733 EP 746 DI 10.1016/j.solmat.2004.07.047 PG 14 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 927CR UT WOS:000229170500071 ER PT J AU McAteer, RTJ Gallagher, PT Ireland, J Young, CA AF McAteer, RTJ Gallagher, PT Ireland, J Young, CA TI Automated boundary-extraction and region-growing techniques applied to solar magnetograms SO SOLAR PHYSICS LA English DT Article ID MICHELSON DOPPLER IMAGER; ACTIVE REGIONS; MAGNETIC-FIELDS; FLARES; FLUX AB We present an automated approach to active region extraction from full-disc MDI longitudinal magnetograms. This uses a region-growing technique in conjunction with boundary-extraction to define a number of enclosed contours as belonging to separate regions of magnetic significance on the solar disc. This provides an objective definition of active regions and areas of plage on the Sun. A number of parameters relating to the flare potential of each region are discussed. C1 NASA, Goddard Space Flight Ctr, Natl Res Council, Greenbelt, MD 20771 USA. Univ Coll Dublin, Dept Expt Phys, Dublin 4, Ireland. NASA, Goddard Space Flight Ctr, L3 Commun GSI, Greenbelt, MD 20771 USA. RP McAteer, RTJ (reprint author), NASA, Goddard Space Flight Ctr, Natl Res Council, Code 661, Greenbelt, MD 20771 USA. EM j.mcateer@grasshopper.gsfc.nasa.gov RI McAteer, R. T. James/D-3736-2011; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 22 TC 27 Z9 27 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2005 VL 228 IS 1-2 BP 55 EP 66 DI 10.1007/s11207-005-4075-x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 969AP UT WOS:000232206100005 ER PT J AU McIntosh, SW Gurman, JB AF McIntosh, SW Gurman, JB TI Nine years of EUV bright points SO SOLAR PHYSICS LA English DT Article ID RECONNECTION; MODELS; CORONA; EIT AB We discuss early results derived from an algorithm that automates the detection, cataloging, and analysis of extreme-ultraviolet (EUV) "bright points" (BP) from 9 years of data acquired by the Extreme-ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO). The algorithm relies upon the computation of a map of "intensity significance"; this then contains the location of the EUV BPs. By mapping the location of BPs in each image and linking them through long sequences of EIT images we can describe the temporal and spatial variations of the 1.3x 10(8) stop EUV BPs observed by SOHO to date. We suggest that there is a considerable amount of physical information about the solar coronal plasma that can be readily gleamed from the BP detection database. In this paper we discuss only a small portion of the possible correlations, but we point to the possibility of BP lifetime distributions that are well described by modified power-laws; the components of which vary with the different temperature filters and with time over the present solar cycle. C1 SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. RP McIntosh, SW (reprint author), SW Res Inst, Dept Space Studies, 1050 Walnut St,Suite 400, Boulder, CO 80302 USA. EM mcintosh@boulder.swri.edu; gurman@gsfc.nasa.gov NR 28 TC 37 Z9 38 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 2005 VL 228 IS 1-2 BP 285 EP 299 DI 10.1007/s11207-005-4725-z PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 969AP UT WOS:000232206100019 ER PT J AU DellaCorte, D AF DellaCorte, D TI Not just another hole in the ground SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP DellaCorte, D (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD MAY PY 2005 VL 61 IS 5 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 925DQ UT WOS:000229032100002 ER PT J AU Lee, SI Howell, SW Raman, A Reifenberger, R Nguyen, CV Meyyappan, M AF Lee, SI Howell, SW Raman, A Reifenberger, R Nguyen, CV Meyyappan, M TI Complex dynamics of carbon nanotube probe tips SO ULTRAMICROSCOPY LA English DT Article DE carbon nanotubes; atomic force microscopes; nonlinear dynamics ID ATOMIC-FORCE MICROSCOPY; DNA AB Carbon nanotube (CNT) tips in tapping mode atomic force microscopy (AFM) enable very high-resolution imaging, measurements, and manipulation at the nanoscale. We present recent results based on experimental analysis that yield new insights into the dynamics of CNT probe tips in tapping mode AFM. Experimental measurements are presented of the frequency response and dynamic amplitude-distance data of a high-aspect-ratio multi-waited (MW) CNT tip. Higher harmonics of the microcantilever are measured in frequency ranges corresponding to attractive regime and the repulsive regime where the CNT buckles dynamically. Surface scanning is performed using a MWCNT tip on a SiO2 grating to verify the imaging instabilities associated with MWCNT buckling when used with normal control schemes in the tapping mode. Lastly, the choice of optimal setpoints for tapping mode control using CNT tip are discussed using the experimental results. (c) 2004 Elsevier B.V. All rights reserved. C1 Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ELORET Corp, Moffett Field, CA 94035 USA. RP Raman, A (reprint author), Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. EM raman@ecn.purdue.edu NR 14 TC 14 Z9 14 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD MAY PY 2005 VL 103 IS 2 BP 95 EP 102 DI 10.1016/j.ultramic.2004.09.012 PG 8 WC Microscopy SC Microscopy GA 912XL UT WOS:000228113100001 PM 15774270 ER PT J AU Mann, JL Long, SE Shuman, CA Kelly, WR AF Mann, JL Long, SE Shuman, CA Kelly, WR TI Determination of mercury content in a shallow firn core from Greenland by isotope dilution inductively coupled plasma mass spectrometry SO WATER AIR AND SOIL POLLUTION LA English DT Article DE firn core; Greenland; isotope dilution; mercury; trace ID GASEOUS MERCURY; SNOW; WATER; DEPOSITION; ICE; PRECONCENTRATION; ACCUMULATION; TEMPERATURE; SPRINGTIME; DEPLETION AB The total mercury content was determined in 6 cm sections of a shallow 7 m firn core and in surrounding surface snow from Summit, Greenland (elevation: 3238 m, 72.58 degrees N, 38.53 degrees W) collected in May 2001 by isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICP-MS). The focus of this research was to evaluate the capability of the ID-CV-ICP-MS technique for measuring trace levels of Hg typical of polar snow and firn. Highly enriched Hg-201 isotopic spike is added to approximately 10 mL melted core and thoroughly mixed. The Hg2+ in the sample is reduced on line with tin(II) chloride (SnCl2) and the elemental Hg (Hg degrees) vapor pre- concentrated onto gold gauze using a commercial amalgam system. The Hg is then thermally desorbed and introduced into a quadrupole ICP-MS. The blank-corrected Hg concentrations determined for all samples ranged from 0.25 to 1.74 ng/L (ppt) (average 0.59 +/- 0.28 ng/L (1 sigma)) and fall within the range of those previously determined by Boutron et al. [Geophys. Res. Lett. 25, 1998, 3315-3318] (<= 0.05-2.0 ng/L) for the Summit site. The average blank value was 0.19 +/- 0.045 ng/L (n = 6, 1 sigma) and the method detection limit was 0.14 ng/L. The Hg values specifically for the firn core range from 0.25 to 0.87 ng/L (average 0.51 +/- 0.13 ng/L (1 sigma)) and show both values declining with time and larger variability in concentration in the top 1.8 m. C1 NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Ft Washington, MD 20744 USA. RP Mann, JL (reprint author), NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. EM jmann@nist.gov NR 40 TC 17 Z9 20 U1 2 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD MAY PY 2005 VL 163 IS 1-4 BP 19 EP 32 DI 10.1007/s11270-005-7607-y PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 938AX UT WOS:000229973400003 ER PT J AU Yoon, KE Sudbrack, CK Noebe, RD Seidman, DN AF Yoon, KE Sudbrack, CK Noebe, RD Seidman, DN TI The temporal evolution of the nanostructures of model Ni-Al-Cr and Ni-Al-Cr-Re superalloys SO ZEITSCHRIFT FUR METALLKUNDE LA English DT Article; Proceedings Paper CT EuroConference on Interfaces in Nanostructured Materials CY JUN 06-11, 2004 CL Kloster Irsee, GERMANY DE Ni-based superalloys; three dimensional atom probe microscopy; temporal evolution; nanostructures ID ATOM-PROBE; ALLOYS AB The temporal evolution of gamma'(L1(2))-precipitates in Ni-5.2 Al-14.2 Cr at.% and Ni-9.5 Al-8.6 Cr-2.0 Re at.% alloys are studied utilizing three-dimensional atom-probe microscopy. For the times investigated (0.0833 to 1024 h), these alloys exhibit a high number density (10(22) - 10(24) M-3) of spheroidal gamma'-precipitates, 0.45 - 30 nm in radius. For the Ni 5.2 Al-14.2 Cr at.% alloy, nucleation, growth, and coarsening of the gamma'-precipitates is observed during the isothermal transformation at 873 K. Precipitate coalescence is present, and its influence on the power-law dependencies of the number density and mean radius during coarsening is discussed and compared to classical models. For Ni-9.5 Al-8.6 Cr-2.0 Re at.%, phase separation occurs during the initial quench leading to a highly interconnected gamma'-nanostructure. The temporal evolution of the elemental partitioning behavior at 1073 K between the gamma-matrix and gamma'-precipitates is studied in detail. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA John H Glenn Res Ctr, Cleveland, OH USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, 2220 Campus Dr, Evanston, IL 60208 USA. EM d-seidman@northwestem.edu RI Seidman, David/B-6697-2009 NR 15 TC 12 Z9 12 U1 0 U2 3 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0044-3093 J9 Z METALLKD JI Z. Metallk. PD MAY PY 2005 VL 96 IS 5 BP 481 EP 485 PG 5 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 937MP UT WOS:000229928700013 ER PT J AU Leblanc, SG Chen, JM Fernandes, R Deering, DW Conley, A AF Leblanc, SG Chen, JM Fernandes, R Deering, DW Conley, A TI Methodology comparison for canopy structure parameters extraction from digital hemispherical photography in boreal forests SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE leaf area index; canopy architecture; TRAC; hemispherical photography ID LEAF-AREA INDEX; CONIFER FORESTS; PLANT CANOPIES; ARCHITECTURE; STANDS; FILM; LAI; VALIDATION; FREQUENCY; INVERSION AB The retrieval of canopy architectural parameters using off-the-shelf digital cameras with fish-eye lens is investigated. The technique used takes advantage of the sensor's linear response to light of these cameras to improve the estimation of gap fraction using: (1) the digital numbers of mixed sky-canopy pixels to estimate the within-pixel gap fraction; and (2) this process is done considering the variation in view zenith angle to take into account the sky radiance distribution and the canopy multiple scattering effects. The foliage element clumping index is retrieved over a wide range of view zenith angles using: (1) the accumulated gap size distribution theory developed for the TRAC by Chen and Cihlar (1995a); C (2) the Lang and Xiang (1986) finite-length averaging method; and (3) a method combining the gap size distribution and the Lang and Xiang finite-length methods. Using data from Canadian and Russian boreal forests, comparisons of gap fraction, clumping index and plant area index measured with the tracing radiation and architecture of canopies (TRAC) and digital hemispherical photography are presented. Evaluation of the LAI estimated from digital hemispherical photography with allometric LAI of two boreal forest stands suggest that that the clumping index combined method may be more accurate. © 2005 Published by Elsevier B.V. C1 Canada Ctr Remote Sensing, Nat Resources Canada, St Hubert, PQ J3Y 8Y9, Canada. Univ Toronto, Dept Geog, Toronto, ON M5S 3G3, Canada. Univ Toronto, Program Planning, Toronto, ON M5S 3G3, Canada. Canada Ctr Remote Sensing, Nat Resources Canada, Ottawa, ON K1A OY7, Canada. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, SSAI, Greenbelt, MD 20771 USA. RP Leblanc, SG (reprint author), Canada Ctr Remote Sensing, Nat Resources Canada, 6767 Route Aeroport, St Hubert, PQ J3Y 8Y9, Canada. EM Sylvain.Leblanc@CCRS.NRCan.gc.ca; chenj@geog.utoronto.ca; Richard.Fernandes@CCRS.NRCAN.gc.ca; Donald.Deering@gsfc.nasa.gov; Alexis.Conley@gsfc.nasa.gov NR 64 TC 190 Z9 208 U1 11 U2 45 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD APR 30 PY 2005 VL 129 IS 3-4 BP 187 EP 207 DI 10.1016/j.agrformet.2004.09.006 PG 21 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 922CI UT WOS:000228813100006 ER PT J AU Fromm, M Bevilacqua, R Servranckx, R Rosen, J Thayer, JP Herman, J Larko, D AF Fromm, M Bevilacqua, R Servranckx, R Rosen, J Thayer, JP Herman, J Larko, D TI Pyro-cumulonimbus injection of smoke to the stratosphere: Observations and impact of a super blowup in northwestern Canada on 3-4 August 1998 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FOREST-FIRE SMOKE; TROPOSPHERE EXCHANGE; SATELLITE DETECTION; MIDDLE ATMOSPHERE; POLAR OZONE; POAM III; SAGE-II; AEROSOL; TRANSPORT; INSTRUMENT AB We report observations and analysis of a pyro-cumulonimbus event in the midst of a boreal forest fire blowup in Northwest Territories Canada, near Norman Wells, on 3-4 August 1998. We find that this blowup caused a five-fold increase in lower stratospheric aerosol burden, as well as multiple reports of anomalous enhancements of tropospheric gases and aerosols across Europe 1 week later. Our observations come from solar occultation satellites (POAM III and SAGE II), nadir imagers (GOES, AVHRR, SeaWiFS, DMSP), TOMS, lidar, and backscattersonde. First, we provide a detailed analysis of the 3 August eruption of extreme pyro-convection. This includes identifying the specific pyro-cumulonimbus cells that caused the lower stratospheric aerosol injection, and a meteorological analysis. Next, we characterize the altitude, composition, and opacity of the post-convection smoke plume on 4-7 August. Finally, the stratospheric impact of this injection is analyzed. Satellite images reveal two noteworthy pyro-cumulonimbus phenomena: (1) an active-convection cloud top containing enough smoke to visibly alter the reflectivity of the cloud anvil in the Upper Troposphere Lower Stratosphere (UTLS) and (2) a smoke plume, that endured for at least 2 hours, atop an anvil. The smoke pall deposited by the Norman Wells pyro-convection was a very large, optically dense, UTLS-level plume on 4 August that exhibited a mesoscale cyclonic circulation. An analysis of plume color/texture from SeaWiFS data, aerosol index, and brightness temperature establishes the extreme altitude and "pure" smoke composition of this unique plume. We show what we believe to be a first-ever measurement of strongly enhanced ozone in the lower stratosphere mingled with smoke layers. We conclude that two to four extreme pyro-thunderstorms near Norman Wells created a smoke injection of hemispheric scope that substantially increased stratospheric optical depth, transported aerosols 7 km above the tropopause (above similar to 430 K potential temperature), and also perturbed lower stratospheric ozone. C1 USN, Res Lab, Washington, DC 20375 USA. Canadian Meteorol Ctr, Dorval, PQ H9P 1J3, Canada. Univ Wyoming, Dept Phys & Astron, Dept 3905, Laramie, WY 82071 USA. Univ Colorado, Dept Aerosp Engn Sci, Ctr Engn, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP USN, Res Lab, Code 7227,4555 Overlook Ave SW, Washington, DC 20375 USA. EM mike.fromm@nrl.navy.mil RI Fromm, Michael/F-4639-2010; THAYER, JEFFREY P./B-7264-2016 OI THAYER, JEFFREY P./0000-0001-7127-8251 NR 37 TC 83 Z9 84 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 30 PY 2005 VL 110 IS D8 AR D08205 DI 10.1029/2004JD005350 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 923GK UT WOS:000228897700001 ER PT J AU Lin, RF Starr, DO Reichardt, J DeMott, PJ AF Lin, RF Starr, DO Reichardt, J DeMott, PJ TI Nucleation in synoptically forced cirrostratus SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HOMOGENEOUS ICE NUCLEATION; GENERAL-CIRCULATION MODEL; CIRRUS CLOUD FORMATION; RELATIVE-HUMIDITY; OPTICAL-PROPERTIES; CLIMATE MODELS; RAMAN LIDAR; WAVE CLOUDS; WATER; MICROPHYSICS AB Formation and evolution of cirrostratus in response to weak, uniform, and constant synoptic forcing is simulated using a one-dimensional numerical model with explicit microphysics, in which the particle size distribution in each grid box is fully resolved. A series of tests of the model response to nucleation modes (homogeneous-freezing-only/heterogeneous nucleation) and heterogeneous nucleation parameters are performed. In the case studied here, nucleation is first activated in the prescribed moist layer. A continuous cloud-top nucleation zone with a depth depending on the vertical humidity gradient and one of the nucleation parameters is developed afterward. For the heterogeneous nucleation cases, intermittent nucleation zones in the mid-upper portion of the cloud form where the relative humidity is on the rise because existent ice crystals falling from higher nucleation zones do not efficiently deplete the excess water vapor and ice nuclei are available. Vertical resolution as fine as 1 m is required for realistic simulation of the homogeneous-freezing-only scenario, while the model resolution requirement is more relaxed in the cases where heterogeneous nucleation dominates. Bulk microphysical and optical properties are evaluated and compared. Ice particle number flux divergence, which is due to the vertical gradient of the gravity-induced particle sedimentation, is constantly and rapidly changing the local ice number concentration, even in the nucleation zone. When the depth of the nucleation zone is shallow, particle number concentration decreases rapidly as ice particles grow and sediment away from the nucleation zone. When the depth of the nucleation zone is large, a region of high ice number concentration can be sustained. The depth of nucleation zone is an important parameter to be considered in parametric treatments of ice cloud generation. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. DWD Meteorol Observ Lindenberg, D-15848 Tauche, Germany. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Lin, RF (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Code 613-1, Greenbelt, MD 20771 USA. EM lin@agnes.gsfc.nasa.gov RI DeMott, Paul/C-4389-2011 OI DeMott, Paul/0000-0002-3719-1889 NR 46 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 30 PY 2005 VL 110 IS D8 AR D08208 DI 10.1029/2004JD005362 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 923GK UT WOS:000228897700002 ER PT J AU Hoge, FE Lyon, PE AF Hoge, FE Lyon, PE TI New tools for the study of oceanic eddies: Satellite derived inherent optical properties SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE eddies; remote sensing; optical properties; organic matter; phytoplankton; Gulf Stream ID DISSOLVED ORGANIC-MATTER; WARM-CORE RING; ABSORPTION-COEFFICIENT; RADIANCE MODEL; MATRIX-INVERSION; ATLANTIC BIGHT; RETRIEVAL; VARIABILITY; PIGMENT; IMAGERY AB Satellite study of oceanic eddy formation, propagation, interactions, and fate was first conducted by sea surface temperature derived at infrared wavelengths. For visible wavelength ocean color reflectances, it is shown that recent radiative transfer model inversions provide additional characteristics of eddies: their constituent absorption and backscattering inherent optical properties. The chromophoric dissolved organic matter absorption coefficient has the highest contrast and is therefore the most visually evident inherent optical property (while the phytoplankton absorption coefficient and backscattering coefficients are respectively less discernible). For use as an analytical tool, comparisons suggests that the chromophoric, dissolved organic matter absorption coefficient has a similar to 10x higher contrast (i.e., similar to 5% vs. 50%) in the Middle Atlantic Bight making eddy events detectable over longer time periods than with SST imagery. Example imagery illustrates the application of chromophoric dissolved organic matter and phytoplankton absorption coefficient inherent optical properties to the visual injection of dissolved and particulate organic carbon into the deep ocean by a Gulf Stream ring. Published by Elsevier Inc. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EG&G Inc, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Bldg N-159,Room E200, Wallops Isl, VA 23337 USA. EM frank.hoge@nasa.gov NR 18 TC 10 Z9 11 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR 30 PY 2005 VL 95 IS 4 BP 444 EP 452 DI 10.1016/j.rse.2004.12.017 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 920QP UT WOS:000228705500003 ER PT J AU Liu, J Drummond, JR Li, QB Gille, JC Ziskin, DC AF Liu, J Drummond, JR Li, QB Gille, JC Ziskin, DC TI Satellite mapping of CO emission from forest fires in Northwest America using MOPITT measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MOPITT; fire emission; carbon monoxide; remote sensing; biomass burning; CO pollution; biosphere-atmosphere interaction ID TROPOSPHERIC CARBON-MONOXIDE; VEGETATION FIRE; TEMPORAL DISTRIBUTION; MIXING RATIOS; BOREAL FOREST; ART.; BIOMASS; POLLUTION; INSTRUMENT; ALGORITHMS AB We present a study on MOPITT (Measurements Of Pollution In The Troposphere) detection of CO emission from large forest fires in the year 2000 in the northwest United States. Fire data used are from the space-borne Advanced Very High Resolution Radiometer (AVHRR) at 1 -km resolution. The study shows that MOPITT can reliably detect CO plumes from forest fires whenever there are > 30 AVHRR hotspots in a 0.25 degrees x 0.25 degrees grid, which is comparable to the pixel area of MOPITT in the region. The spatial CO pattern during the fire events is found to be consistent with the location and density of AVHRR hotspots and wind direction. While the increase of CO abundance inside the study area is closely correlated to the AVHRR-derived hotspot number in general (R > 0.75), the non-linearity of fire emission with fuel consumption is also observed. MOPITT can also capture the temporal variation in CO emission from forest fires through 3 -day composites so it may offer an opportunity to enhance our knowledge of temporal fire emission over large areas. The CO emission is quantitatively estimated with a one-box model. The result is compared with a bottom-up approach using surface data including burnt area, biomass density, and fire emission factors. If mean emission factors for the region are used, the bottom-up approach results in total emission estimates which are 10%-50% lower than the MOPITT-based estimate. In spite of the limitations and uncertainties addressed in this study, MOPITT data may provide a useful constraint on uncertain ground-based fire emission estimates. (c) 2005 Elsevier Inc. All rights reserved. C1 Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Liu, J (reprint author), Univ Toronto, Dept Phys, 60 St George St, Toronto, ON M5S 1A7, Canada. EM jliu@atmosp.physics.utoronto.ca RI Drummond, James/O-7467-2014 NR 62 TC 28 Z9 28 U1 0 U2 12 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR 30 PY 2005 VL 95 IS 4 BP 502 EP 516 DI 10.1016/j.rse.2005.01.009 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 920QP UT WOS:000228705500008 ER PT J AU Ito, TM Prezeau, G AF Ito, TM Prezeau, G TI Neutrino mass constraints on beta decay SO PHYSICAL REVIEW LETTERS LA English DT Article ID COSMOLOGICAL PARAMETERS; LIMITS; CURRENTS; PHYSICS; AR-32; WMAP AB Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-standard-model interactions that can generate loop corrections to the neutrino mass, we derive constraints on some non-standard-model d -> ue(-)(v) over bar interactions. When cast into limits on n -> pe(-)(v) over bar coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield |C-S/C-V|less than or similar to 5x10(-3), vertical bar C-S'/C-V vertical bar less than or similar to 5x10(-3), vertical bar C-T/C-A vertical bar less than or similar to 1.2x10(-2), and vertical bar C-T'/C-A vertical bar less than or similar to 1.2x10(-2). C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 21 TC 14 Z9 14 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 2005 VL 94 IS 16 AR 161802 DI 10.1103/PhysRevLett.94.161802 PG 4 WC Physics, Multidisciplinary SC Physics GA 921KS UT WOS:000228763800016 PM 15904212 ER PT J AU Orsolini, YJ Manney, GL Santee, ML Randall, CE AF Orsolini, YJ Manney, GL Santee, ML Randall, CE TI An upper stratospheric layer of enhanced HNO3 following exceptional solar storms SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VORTEX; ATMOSPHERE; NITROGEN AB An analysis of stratospheric nitric acid (HNO3) observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) reveals a distinct, high-altitude maximum, that appeared in late November 2003 in the polar upper stratosphere. Confined to the polar vortex, the enhanced HNO3 layer intensified while descending to the middle stratosphere, and disappeared between mid-January and mid-February. The high-altitude maximum is considerably enhanced compared to the weak, secondary maxima previously reported in the literature. Analysis of MIPAS stratospheric nitrogen dioxide (NO2) and correlations with the geomagnetic Ap index suggest that particle precipitation from the intense solar storms of October - November 2003 was responsible for this extraordinary high- altitude HNO3 layer. The detailed morphology and time-evolution of such a distinct, high-altitude HNO3 layer have not been observed before, nor the link to geomagnetic activity through contemporaneous upper stratospheric NO2 measurements. C1 Norwegian Inst Air Res, N-2027 Kjeller, Norway. CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NV USA. RP Orsolini, YJ (reprint author), Norwegian Inst Air Res, POB 100, N-2027 Kjeller, Norway. EM orsolini@nilu.no RI Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 19 TC 47 Z9 47 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 28 PY 2005 VL 32 IS 12 AR L12S01 DI 10.1029/2004GL021588 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 923GF UT WOS:000228897200003 ER PT J AU Hurley, K Boggs, SE Smith, DM Duncan, RC Lin, R Zoglauer, A Krucker, S Hurford, G Hudson, H Wigger, C Hajdas, W Thompson, C Mitrofanov, I Sanin, A Boynton, W Fellows, C von Kienlin, A Lichti, G Rau, A Cline, T AF Hurley, K Boggs, SE Smith, DM Duncan, RC Lin, R Zoglauer, A Krucker, S Hurford, G Hudson, H Wigger, C Hajdas, W Thompson, C Mitrofanov, I Sanin, A Boynton, W Fellows, C von Kienlin, A Lichti, G Rau, A Cline, T TI An exceptionally bright flare from SGR 1806-20 and the origins of short-duration gamma-ray bursts SO NATURE LA English DT Article ID MAGNETIZED NEUTRON-STARS; 1998 AUGUST 27; 1979 MARCH 5; X-RAY; SGR 1900+14; RADIATIVE MECHANISM; GIANT FLARE; LBV 1806-20; REPEATERS; SPECTRUM AB Soft-gamma-ray repeaters (SGRs) are galactic X-ray stars that emit numerous short-duration (about 0.1 s) bursts of hard X-rays during sporadic active periods. They are thought to be magnetars: strongly magnetized neutron stars with emissions powered by the dissipation of magnetic energy. Here we report the detection of a long (380 s) giant flare from SGR 1806-20, which was much more luminous than any previous transient event observed in our Galaxy. (In the first 0.2 s, the flare released as much energy as the Sun radiates in a quarter of a million years.) Its power can be explained by a catastrophic instability involving global crust failure and magnetic reconnection on a magnetar, with possible large-scale untwisting of magnetic field lines outside the star. From a great distance this event would appear to be a short-duration, hard-spectrum cosmic gamma-ray burst. At least a significant fraction of the mysterious short-duration gamma-ray bursts may therefore come from extragalactic magnetars. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Space Res Inst, Moscow 117997, Russia. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. EM khurley@ssl.berkeley.edu RI Boggs, Steven/E-4170-2015 OI Boggs, Steven/0000-0001-9567-4224 NR 50 TC 330 Z9 333 U1 0 U2 9 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD APR 28 PY 2005 VL 434 IS 7037 BP 1098 EP 1103 DI 10.1038/nature03519 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 920MD UT WOS:000228693300034 PM 15858565 ER PT J AU Gaensler, BM Kouveliotou, C Gelfand, JD Taylor, GB Eichler, D Wijers, RAMJ Granot, J Ramirez-Ruiz, E Lyubarsky, YE Hunstead, RW Campbell-Wilson, D van der Horst, AJ McLaughlin, MA Fender, RP Garrett, MA Newton-McGee, KJ Palmer, DM Gehrels, N Woods, PM AF Gaensler, BM Kouveliotou, C Gelfand, JD Taylor, GB Eichler, D Wijers, RAMJ Granot, J Ramirez-Ruiz, E Lyubarsky, YE Hunstead, RW Campbell-Wilson, D van der Horst, AJ McLaughlin, MA Fender, RP Garrett, MA Newton-McGee, KJ Palmer, DM Gehrels, N Woods, PM TI An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20 SO NATURE LA English DT Article ID RAY REPEATER SGR1900+14; SOFT GAMMA-REPEATERS; RADIATIVE MECHANISM; SGR 1806-20; PULSAR; SGR-1900+14; AFTERGLOWS AB Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximate to 10(15) gauss (refs 1-3). On 27 December 2004, a giant flare(4) was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded(5,6). This burst of energy was detected by a variety of instruments(7,8) and even caused an ionospheric disturbance in the Earth's upper atmosphere that was recorded around the globe(9). Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source(10). From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter of the speed of light. To create this nebula, at least 4 x 10(43) ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94309 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Inst Adv Study, Princeton, NJ 08540 USA. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Joint Inst VLBI Europe, NL-7990 AA Dwingeloo, Netherlands. CSIRO, Australia Telescope Natl Facil, Epping, NSW 1710, Australia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gaensler, BM (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM bgaensler@cfa.harvard.edu RI Gaensler, Bryan/F-8655-2010; Gehrels, Neil/D-2971-2012; LYUBARSKY, YURY/F-2362-2012; OI Wijers, Ralph/0000-0002-3101-1808; Gaensler, Bryan/0000-0002-3382-9558 NR 27 TC 105 Z9 105 U1 0 U2 4 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 28 PY 2005 VL 434 IS 7037 BP 1104 EP 1106 DI 10.1038/nature03498 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 920MD UT WOS:000228693300035 PM 15858566 ER PT J AU Palmer, DM Barthelmy, S Gehrels, N Kippen, RM Cayton, T Kouveliotou, C Eichler, D Wijers, RAMJ Woods, PM Granot, J Lyubarsky, YE Ramirez-Ruiz, E Barbier, L Chester, M Cummings, J Fenimore, EE Finger, MH Gaensler, BM Hullinger, D Krimm, H Markwardt, CB Nousek, JA Parsons, A Patel, S Sakamoto, T Sato, G Suzuki, M Tueller, J AF Palmer, DM Barthelmy, S Gehrels, N Kippen, RM Cayton, T Kouveliotou, C Eichler, D Wijers, RAMJ Woods, PM Granot, J Lyubarsky, YE Ramirez-Ruiz, E Barbier, L Chester, M Cummings, J Fenimore, EE Finger, MH Gaensler, BM Hullinger, D Krimm, H Markwardt, CB Nousek, JA Parsons, A Patel, S Sakamoto, T Sato, G Suzuki, M Tueller, J TI A giant gamma-ray flare from the magnetar SGR 1806-20 SO NATURE LA English DT Article ID REPEATER SGR 1900+14; 1998 AUGUST 27; RADIATIVE MECHANISM; BURST; OUTBURSTS; MISSION AB Two classes of rotating neutron stars-soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars-are magnetars(1), whose X-ray emission is powered by a very strong magnetic field (B approximate to 10(15) G). SGRs occasionally become 'active', producing many short X-ray bursts. Extremely rarely, an SGR emits a giant flare with a total energy about a thousand times higher than in a typical burst(2-4). Here we report that SGR 1806-20 emitted a giant flare on 27 December 2004. The total (isotropic) flare energy is 2 x 10(46) erg, which is about a hundred times higher than the other two previously observed giant flares. The energy release probably occurred during a catastrophic reconfiguration of the neutron star's magnetic field. If the event had occurred at a larger distance, but within 40 megaparsecs, it would have resembled a short, hard gamma-ray burst, suggesting that flares from extragalactic SGRs may form a subclass of such bursts. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94309 USA. Inst Adv Study, Princeton, NJ 08540 USA. Penn State Univ, University Pk, PA 16802 USA. CNR, Washington, DC 20001 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Maryland, College Pk, MD 20742 USA. Inst Space & Astronaut Sci, JAXA, Kanagawa 2298510, Japan. Saitama Univ, Sakura Ku, Saitama 3388570, Japan. RP Palmer, DM (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM palmer@lanl.gov RI Gaensler, Bryan/F-8655-2010; Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; LYUBARSKY, YURY/F-2362-2012; Parsons, Ann/I-6604-2012; OI Wijers, Ralph/0000-0002-3101-1808 NR 22 TC 289 Z9 292 U1 0 U2 9 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 28 PY 2005 VL 434 IS 7037 BP 1107 EP 1109 DI 10.1038/nature03525 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 920MD UT WOS:000228693300036 PM 15858567 ER PT J AU Hampton, J Sibert, JR Kleiber, P Maunder, MN Harley, SJ AF Hampton, J Sibert, JR Kleiber, P Maunder, MN Harley, SJ TI Decline of Pacific tuna populations exaggerated? SO NATURE LA English DT Editorial Material ID THUNNUS-OBESUS; BIGEYE TUNA; MODEL; OCEAN C1 Secretariat Pacific Community, Ocean Fisheries Programme, Noumea 98848, New Caledonia. Univ Hawaii, Pelag Fisheries Res Program, Honolulu, HI 96822 USA. Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. Interamer Trop Tuna Commiss, La Jolla, CA 92037 USA. RP Hampton, J (reprint author), Secretariat Pacific Community, Ocean Fisheries Programme, BP D5, Noumea 98848, New Caledonia. EM johnh@spc.int NR 14 TC 69 Z9 73 U1 2 U2 12 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 28 PY 2005 VL 434 IS 7037 BP E1 EP E2 DI 10.1038/nature03581 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 920MD UT WOS:000228693300030 PM 15858533 ER PT J AU Nieto, MM Turyshev, SG Anderson, JD AF Nieto, MM Turyshev, SG Anderson, JD TI Directly measured limit on the interplanetary matter density from Pioneer 10 and 11 SO PHYSICS LETTERS B LA English DT Article DE pioneer anomaly; interplanetary medium; drag force ID SOLAR-SYSTEM; DARK-MATTER; KUIPER-BELT; DUST; ACCELERATION; NEPTUNE; ULYSSES; GALILEO; SEARCH; COMETS AB The Pioneer 10 and 11 spacecraft had exceptional deep-space navigational capabilities. The accuracies of their orbit reconstruction were limited, however, by a small, anomalous, Doppler frequency drift that can be interpreted as an acceleration of (8.74 +/- 1.33) x 10(-8) cm/s(2) directed toward the Sun. We investigate the possibility that this anomaly could be due to a drag on the spacecraft from their passing through the interplanetary medium. Although this mechanism is an appealing one, the existing Pioneer radiometric data would require an unexpectedly high mass density of interplanetary dust for this mechanism to work. Further, the magnitude of the density would have to be nearly constant at distances similar to 20-70 AU. Therefore, it appears that such an explanation is very unlikely, if not ruled out. Despite this, the measured frequency drift by itself places a directly-measured, model-independent limit of <= 3 x 10(-19) g/cm(3) on the mass density of interplanetary dust in the outer (similar to 20-70 AU) solar system. Lower experimental limits can be placed if one presumes a model that varies with distance. An example is the limit <= 6 x 10(-20) g/cm(3) obtained for the model with an axially-symmetric density distribution that falls off as the inverse of the distance. We emphasize that the limits obtained are experimentally-measured, in situ limits. A mission to investigate the anomaly would be able to place a better limit on the density, or perhaps even to measure it. (c) 2005 Elsevier B.V. All rights reserved. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nieto, MM (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos Natl Lab, MS-B285, Los Alamos, NM 87545 USA. EM mmn@lanl.gov; turyshev@jpl.nasa.gov; john.d.anderson@jpl.nasa.gov NR 41 TC 30 Z9 30 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 28 PY 2005 VL 613 IS 1-2 BP 11 EP 19 DI 10.1016/j.physletb.2005.03.035 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 921OK UT WOS:000228773900003 ER PT J AU Jin, ML Shepherd, JM King, MD AF Jin, ML Shepherd, JM King, MD TI Urban aerosols and their variations with clouds and rainfall: A case study for New York and Houston SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; PHOTOCHEMICAL AIR-POLLUTION; WEEKDAY-WEEKEND DIFFERENCES; POLAR ORBITING SATELLITES; OPTICAL-PROPERTIES; SKIN TEMPERATURE; TRMM SATELLITE; DIURNAL CYCLE; WATER-VAPOR; HEAT-ISLAND AB Diurnal, weekly, seasonal, and interannual variations of urban aerosols were analyzed with an emphasis on summer months using 4 years of the NASA Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) observations, in situ Aerosol Robotic Network (AERONET) observations, and in situ U. S. Environmental Protection Agency (EPA) PM2.5 data for one midlatitude city (New York) and one subtropical city (Houston). Seasonality is evident in aerosol optical thickness measurements, with a minimum in January and a maximum in April to July. The diurnal variations of aerosols, however, are detectable but largely affected by local and regional weather conditions, such as surface and upper-level winds. On calm clear days, aerosols peak during the two rush hours in the morning and evening. Furthermore, the anthropogenic-induced weekly cycles of aerosols and clouds are analyzed, which by themselves are weak, as the anthropogenic signal is mixed with noise of natural weather variability. In addition, corresponding cloud properties observed from MODIS demonstrate an opposite phase to the seasonality of aerosols. Nevertheless, no clear relationship was observed between monthly mean aerosols and rainfall measurements from NASA's Tropical Rainfall Measuring Mission (TRMM), implying that in the summer the aerosol impact may not be the primary reason for the change of urban rainfall amount. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. RP Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. EM mjin@atmos.umd.edu RI King, Michael/C-7153-2011 OI King, Michael/0000-0003-2645-7298 NR 61 TC 71 Z9 73 U1 2 U2 20 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 2005 VL 110 IS D10 AR D10S20 DI 10.1029/2004JD005081 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 923GM UT WOS:000228897900001 ER PT J AU Eitzen, ZA Xu, KM AF Eitzen, ZA Xu, KM TI A statistical comparison of deep convective cloud objects observed by an Earth Observing System satellite and simulated by a cloud-resolving model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NONHYDROSTATIC ATMOSPHERIC SIMULATION; REMOTE-SENSING APPLICATIONS; MEASURING MISSION TRMM; MELTING-LAYER MODEL; BULK ICE SCHEME; PHASE-III DATA; RADIATIVE PROPERTIES; EXPLICIT SIMULATION; CUMULUS ENSEMBLES; CLIMATE MODELS AB The single scanner footprint (SSF) data product produced by the Clouds and the Earth's Radiant Energy System (CERES) instrument on board the Tropical Rainfall Measuring Mission (TRMM) satellite is used to diagnose 68 deep convective cloud objects observed in March 1998. The probability density functions (PDFs) of several observed and retrieved fields from the CERES SSF data product are used to evaluate two sets of simulations produced by a cloud-resolving model. The simulations that use an improved microphysics scheme are found to produce more realistic distributions of albedo, outgoing longwave radiation, cloud top temperature, and cloud height than the control simulations, using an objective measure of the differences between the simulated and observed PDFs. The distribution of cloud optical depth produced by the new simulations is further from that observed than the control simulations. Using a bootstrapping technique, these differences are found to be statistically significant. The reflectivities and precipitation rates associated with the cloud objects observed with the TRMM precipitation radar and TRMM microwave imager are also used to evaluate the two sets of simulations. Both sets are found to produce similar distributions of the precipitation rate. The simulated radar reflectivities produced by the new simulations are somewhat more realistic than those of the control simulations, although both sets produce reflectivities that are too high at altitudes above the freezing level. C1 NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA 23665 USA. RP Eitzen, ZA (reprint author), NASA, Langley Res Ctr, Sci Applicat Int Corp, Mail Stop 420, Hampton, VA 23681 USA. EM z.a.eitzen@larc.nasa.gov; kuan-man.xu@nasa.gov RI Xu, Kuan-Man/B-7557-2013 OI Xu, Kuan-Man/0000-0001-7851-2629 NR 48 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 26 PY 2005 VL 110 IS D15 AR D15S14 DI 10.1029/2004JD005086 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 923GN UT WOS:000228898000003 ER PT J AU Jacob, DJ Field, BD Li, QB Blake, DR de Gouw, J Warneke, C Hansel, A Wisthaler, A Singh, HB Guenther, A AF Jacob, DJ Field, BD Li, QB Blake, DR de Gouw, J Warneke, C Hansel, A Wisthaler, A Singh, HB Guenther, A TI Global budget of methanol: Constraints from atmospheric observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID VOLATILE ORGANIC-COMPOUNDS; TRANSFORM INFRARED-SPECTROSCOPY; SOUTHEASTERN UNITED-STATES; BIOMASS-BURNING EMISSIONS; TRACE GAS MEASUREMENTS; TROPICAL RAIN-FOREST; NONMETHANE HYDROCARBONS; TROPOSPHERIC OZONE; MODEL DESCRIPTION; CARBON-MONOXIDE AB [1] We use a global three-dimensional model simulation of atmospheric methanol to examine the consistency between observed atmospheric concentrations and current understanding of sources and sinks. Global sources in the model include 128 Tg yr(-1) from plant growth, 38 Tg yr(-1) from atmospheric reactions of CH3O2 with itself and other organic peroxy radicals, 23 Tg yr(-1) from plant decay, 13 Tg yr(-1) from biomass burning and biofuels, and 4 Tg yr(-1) from vehicles and industry. The plant growth source is a factor of 3 higher for young than from mature leaves. The atmospheric lifetime of methanol in the model is 7 days; gas-phase oxidation by OH accounts for 63% of the global sink, dry deposition to land 26%, wet deposition 6%, uptake by the ocean 5%, and aqueous-phase oxidation in clouds less than 1%. The resulting simulation of atmospheric concentrations is generally unbiased in the Northern Hemisphere and reproduces the observed correlations of methanol with acetone, HCN, and CO in Asian outflow. Accounting for decreasing emission from leaves as they age is necessary to reproduce the observed seasonal variation of methanol concentrations at northern midlatitudes. The main model discrepancy is over the South Pacific, where simulated concentrations are a factor of 2 too low. Atmospheric production from the CH3O2 self-reaction is the dominant model source in this region. A factor of 2 increase in this source ( to 50 - 100 Tg yr(-1)) would largely correct the discrepancy and appears consistent with independent constraints on CH3O2 concentrations. Our resulting best estimate of the global source of methanol is 240 Tg yr(-1). More observations of methanol concentrations and fluxes are needed over tropical continents. Better knowledge is needed of CH3O2 concentrations in the remote troposphere and of the underlying organic chemistry. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. NOAA, Aeron Lab, Boulder, CO 80305 USA. Univ Innsbruck, Inst Ion Phys, A-6020 Innsbruck, Austria. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. RP Harvard Univ, Div Engn & Appl Sci, Pierce Hall,29 Oxford St, Cambridge, MA 02138 USA. EM djacob@fas.harvard.edu RI Warneke, Carsten/E-7174-2010; Guenther, Alex/B-1617-2008; de Gouw, Joost/A-9675-2008; Hansel, Armin/F-3915-2010 OI Guenther, Alex/0000-0001-6283-8288; de Gouw, Joost/0000-0002-0385-1826; Hansel, Armin/0000-0002-1062-2394 NR 82 TC 134 Z9 135 U1 4 U2 33 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 26 PY 2005 VL 110 IS D8 AR D08303 DI 10.1029/2004JD005172 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 923GI UT WOS:000228897500003 ER PT J AU Bunker, J Lowry, T Davis, G Zhang, B Brosnahan, D Lindsay, S Costen, R Choi, S Arosio, P Watt, GD AF Bunker, J Lowry, T Davis, G Zhang, B Brosnahan, D Lindsay, S Costen, R Choi, S Arosio, P Watt, GD TI Kinetic studies of iron deposition catalyzed by recombinant human liver heavy, and light ferritins and Azotobacter vinelandii bacterioferritin using O-2 and H2O2 as oxidants SO BIOPHYSICAL CHEMISTRY LA English DT Article DE hydrogen peroxide; human liver ferritin; bacterioferritin; iron deposition; recombinant ferritins; kinetics ID HORSE SPLEEN FERRITIN; ESCHERICHIA-COLI BACTERIOFERRITIN; H-CHAIN FERRITIN; HYDROGEN-PEROXIDE; FERROXIDASE REACTION; OXIDATION; PHOSPHATE; MINERALIZATION; INTERMEDIATE; HYDROLYSIS AB The discrepancy between predicted and measured H2O2 formation during iron deposition with recombinant heavy human liver ferritin (rHF) was attributed to reaction with the iron protein complex [Biochemistry 40 (2001) 10832-10838]. This proposal was examined by stopped-flow kinetic studies and analysis for H2O2 production using (1) rHF, and Azotobacter vinelandii bacterial ferritin (AvBF), each containing 24 identical subunits with ferroxidase centers-, (2) site-altered rHF mutants with functional and dysfunctional ferroxidase centers-, and (3) recombinant human liver light ferritin (rLF), containing no ferroxidase center. For rHF, nearly identical pseudo-first-order rate constants of 0.18 s(-1) at pH 7.5 were measured for Fe2+ oxidation by both O-2 and H2O2, but for rLF, the rate with O-2 was 200-fold slower than that for H2O2 (k=0.22 s(-1)). A Fe2+/O-2 stoichiometry near 2.4 was measured for rHF and its site altered forms, suggesting formation of H2O2. Direct measurements revealed no H2O2 free in solution 0.5-10 min after all Fe2+ was oxidized at pH 6.5 or 7.5. These results are consistent with initial H2O2 formation, which rapidly reacts in a secondary reaction with unidentified solution components. Using measured rate constants for rHF, simulations showed that steady-state H2O2 concentrations peaked at 14 mu M at similar to 600 ms and decreased to zero at 10-30 s. rLF did not produce measurable H2O2 but apparently conducted the secondary reaction with H2O2. Fe (2+)/O-2 values of 4.0 were measured for AvBF. Stopped-flow measurements with AvBF showed that both H2O2 and O-2 react at the same rate (k=0.34 s- 1), that is faster than the reactions with rHF. Simulations suggest that AvBF reduces O-2 directly to H2O without intermediate H2O2 formation. (c) 2004 Elsevier B.V All rights reserved. C1 Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. Brigham Young Univ, Undergrad Res Program, Provo, UT USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. DIBIT, San Raffaele Sci Inst, Unit Prot Engn, Milan, Italy. Univ Brescia, Cattedra Chim, Brescia, Italy. RP Watt, GD (reprint author), Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. EM gdwatt@chem.byu.edu OI arosio, paolo/0000-0002-5343-8992 NR 37 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 J9 BIOPHYS CHEM JI Biophys. Chem. PD APR 22 PY 2005 VL 114 IS 2-3 BP 235 EP 244 DI 10.1016/j.bpc.2004.11.008 PG 10 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 919IZ UT WOS:000228613000018 PM 15829358 ER PT J AU Berube, D Moldwin, MB Fung, SF Green, JL AF Berube, D Moldwin, MB Fung, SF Green, JL TI A plasmaspheric mass density model and constraints on its heavy ion concentration SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FIELD LINE RESONANCE; ELECTRON-DENSITY; PLASMA-DENSITY; SATELLITE; STORM; EIGENFREQUENCIES; MAGNETOSPHERE; FREQUENCIES; IMAGE AB [1] The first empirical model of the equatorial mass density of the plasmasphere is constructed using ground-based ULF wave diagnostics. Plasmaspheric mass density between L = 1.7 and L = 3.2 has been determined using over 5200 hours of data from pairs of stations in the MEASURE array of ground magnetometers. The least squares fit to the data as a function of L shows that mass density falls logarithmically with L. Average ion mass as a function of L is also estimated by combining the mass density model with plasmaspheric electron density profiles determined from the IMAGE Radio Plasma Imager (RPI). Additionally, we use the RPI electron density database to examine how the average ion mass changes under different levels of geomagnetic activity. We find that average ion mass is greatest under the most disturbed conditions. This result indicates that heavy ion concentrations ( percent by number) are enhanced during large geomagnetic disturbances. We also find that the average ion mass increases with increasing L ( below L = 3.2), indicating the presence of a heavy ion torus during disturbed times. Heavy ions must play an important role in storm-time plasmaspheric dynamics. The average ion mass is also used to constrain the concentrations of He+ and O+. Estimates of the He+ concentration determined this way may be useful for interpreting IMAGE Extreme Ultraviolet Imager (EUV) images. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. RP Berube, D (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. EM dberube@igpp.ucla.edu RI Moldwin, Mark/F-8785-2011; Fung, Shing/F-5647-2012 OI Moldwin, Mark/0000-0003-0954-1770; NR 29 TC 31 Z9 32 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 22 PY 2005 VL 110 IS A4 AR A04212 DI 10.1029/2004JA010684 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 922RQ UT WOS:000228856000003 ER PT J AU Nallasamy, M Envia, E AF Nallasamy, M Envia, E TI Computation of rotor wake turbulence noise SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB A major source of fan broadband noise is the interaction of rotor wake turbulence with the fan outlet guide vanes. A broadband noise model that utilizes computed rotor flow turbulence from a Reynolds averaged Navier-Stokes code is used to predict fan broadband noise spectra. The noise model is employed to examine the broadband noise characteristics of the 22-in source diagnostic test fan rig for which broadband noise data were obtained in wind tunnel tests at the NASA Glenn Research Center. A 9-case matrix of three outlet guide vane configurations at three representative fan tip speeds are considered. For all cases inlet and exhaust spectra of acoustic power are computed and compared with the measured spectra where possible. The acoustic power levels and shape of the predicted spectra are in good agreement with the measured data for the fan exhaust duct radiation at approach condition where direct comparisons are possible. The predicted spectra show the experimentally observed trends with fan tip speed, vane count and vane sweep. The results also demonstrate the validity of using computational fluid dynamics based turbulence information for fan broadband noise calculations. (c) 2004 Elsevier Ltd. All rights reserved. C1 NASA Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. NASA Glenn Res Ctr, Acoust Branch, Cleveland, OH 44135 USA. RP Nallasamy, M (reprint author), NASA Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. EM nallasamy@grc.nasa.gov NR 20 TC 31 Z9 32 U1 1 U2 3 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD APR 22 PY 2005 VL 282 IS 3-5 BP 649 EP 678 DI 10.1016/j.jsv.2004.03.062 PG 30 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 913RX UT WOS:000228171800004 ER PT J AU Jakosky, BM Anbar, AD Des Marais, D Morrison, D Pace, NR AF Jakosky, BM Anbar, AD Des Marais, D Morrison, D Pace, NR TI Don't dismiss astrobiology SO SCIENCE LA English DT Letter C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Mol Cellular & Dev Biol, Boulder, CO 80309 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jakosky, BM (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 22 PY 2005 VL 308 IS 5721 BP 496 EP 496 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 922BK UT WOS:000228810500025 ER PT J AU Klein, SA Pincus, R Hannay, C Xu, KM AF Klein, SA Pincus, R Hannay, C Xu, KM TI How might a statistical cloud scheme be coupled to a mass-flux convection scheme? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SUBGRID-SCALE VARIABILITY; PLANETARY BOUNDARY-LAYER; CUMULUS CONVECTION; RESOLVING MODEL; PART I; PARAMETERIZATION; ENSEMBLE; IOP AB The coupling of statistical cloud schemes with mass-flux convection schemes is addressed. Source terms representing the impact of convection are derived within the framework of prognostic equations for the width and asymmetry of the probability distribution function of total water mixing ratio. The accuracy of these source terms is quantified by examining output from a cloud-resolving model simulation of deep convection. Practical suggestions for the inclusion of these source terms in large-scale models are offered. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Univ Colorado, Climate Diagnost Ctr, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Klein, SA (reprint author), Lawrence Livermore Natl Lab, Atmospher Sci Div L103, Livermore, CA 94551 USA. EM klein21@llnl.gov RI Xu, Kuan-Man/B-7557-2013; Pincus, Robert/B-1723-2013; Klein, Stephen/H-4337-2016 OI Xu, Kuan-Man/0000-0001-7851-2629; Pincus, Robert/0000-0002-0016-3470; Klein, Stephen/0000-0002-5476-858X NR 23 TC 8 Z9 8 U1 2 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 21 PY 2005 VL 110 IS D15 AR D15S06 DI 10.1029/2004JD005017 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 922QN UT WOS:000228853000001 ER PT J AU Xu, KM Zhang, MH Eitzen, MA Ghan, SJ Klein, SA Wu, XQ Xie, SC Branson, M Del Genio, AD Iacobellis, SF Khairoutdinov, M Lin, WY Lohmann, U Randall, DA Somerville, RCJ Sud, YC Walker, GK Wolf, A Yio, JJ Zhang, JH AF Xu, KM Zhang, MH Eitzen, MA Ghan, SJ Klein, SA Wu, XQ Xie, SC Branson, M Del Genio, AD Iacobellis, SF Khairoutdinov, M Lin, WY Lohmann, U Randall, DA Somerville, RCJ Sud, YC Walker, GK Wolf, A Yio, JJ Zhang, JH TI Modeling springtime shallow frontal clouds with cloud-resolving and single-column models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LARGE-SCALE MODELS; GENERAL-CIRCULATION MODEL; RADIATION MEASUREMENT PROGRAM; CLIMATE MODELS; TOGA-COARE; MICROPHYSICAL PROCESSES; NUMERICAL-SIMULATION; STRATIFORM CLOUDS; WATER-CONTENT; GCSS MODEL AB This modeling study compares the performance of eight single-column models (SCMs) and four cloud-resolving models (CRMs) in simulating shallow frontal cloud systems observed during a short period of the March 2000 Atmospheric Radiation Measurement (ARM) intensive operational period. Except for the passage of a cold front at the beginning of this period, frontal cloud systems are under the influence of an upper tropospheric ridge and are driven by a persistent frontogenesis over the Southern Great Plains and moisture transport from the northwestern part of the Gulf of Mexico. This study emphasizes quantitative comparisons among the model simulations and with the ARM data, focusing on a 27-hour period when only shallow frontal clouds were observed. All CRMs and SCMs simulate clouds in the observed shallow cloud layer. Most SCMs also produce clouds in the middle and upper troposphere, while none of the CRMs produce any clouds there. One possible cause for this is the decoupling between cloud condensate and cloud fraction in nearly all SCM parameterizations. Another possible cause is the weak upper tropospheric subsidence that has been averaged over both descending and ascending regions. Significantly different cloud amounts and cloud microphysical properties are found in the model simulations. All CRMs and most SCMs underestimate shallow clouds in the lowest 125 hPa near the surface, but most SCMs overestimate the cloud amount above this layer. These results are related to the detailed formulations of cloud microphysical processes and fractional cloud parameterizations in the SCMs, and possibly to the dynamical framework and two-dimensional configuration of the CRMs. Although two of the CRMs with anelastic dynamical frameworks simulate the shallow frontal clouds much better than the SCMs, the CRMs do not necessarily perform much better than the SCMs for the entire period when deep and shallow frontal clouds are present. C1 NASA, Climate Sci Branch, Langley Res Ctr, Hampton, VA 23681 USA. SUNY Stony Brook, Marine Sci Res Ctr, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. Sci Applicat Int Corp, Hampton, VA USA. Pacific NW Natl Lab, Div Atmospher Sci, Richland, WA 99352 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. Iowa State Univ, Dept Geol & Atmospher Sci, Ames, IA 50011 USA. Lawrence Livermore Natl Lab, Atmospher Sci Div L103, Livermore, CA 94551 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 3C3, Canada. NASA, Climate & Radiat Branch, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Xu, KM (reprint author), NASA, Climate Sci Branch, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM kuan-man.xu@nasa.gov; mzhang@notes.cc.sunysb.edu; z.a.eitzen@larc.nasa.gov; steve.ghan@pnl.gov; klein21@llnl.gov; xie2@llnl.gov; mark@atmos.colostate.edu; adelgenio@giss.nasa.gov; siacobellis@ucsd.edu; marat@atmos.colostate.edu; wlin@atmsci.msrc.sunysb.edu; randall@atmos.colostate.edu; rsomerville@ucsd.edu; awolf@thelma.giss.nasa.gov; yio1@llnl.gov RI Del Genio, Anthony/D-4663-2012; Xu, Kuan-Man/B-7557-2013; Xie, Shaocheng/D-2207-2013; Wu, Xiangqian/F-5634-2010; Randall, David/E-6113-2011; Ghan, Steven/H-4301-2011; Klein, Stephen/H-4337-2016; Lohmann, Ulrike/B-6153-2009 OI Del Genio, Anthony/0000-0001-7450-1359; Xu, Kuan-Man/0000-0001-7851-2629; Xie, Shaocheng/0000-0001-8931-5145; Wu, Xiangqian/0000-0002-7804-5650; Randall, David/0000-0001-6935-4112; Ghan, Steven/0000-0001-8355-8699; Klein, Stephen/0000-0002-5476-858X; Lohmann, Ulrike/0000-0001-8885-3785 NR 56 TC 29 Z9 29 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 21 PY 2005 VL 110 IS D15 AR D15S04 DI 10.1029/2004JD005153 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 922QN UT WOS:000228853000002 ER PT J AU O'Neill, PM Nandra, K Papadakis, IE Turner, TJ AF O'Neill, PM Nandra, K Papadakis, IE Turner, TJ TI The relationship between X-ray variability amplitude and black hole mass in active galactic nuclei SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID SEYFERT 1 GALAXIES; LINE REGION SIZES; NARROW-LINE; CYGNUS X-1; POWER SPECTRUM; RAPID VARIABILITY; ASCA OBSERVATIONS; HIGH-STATE; TIME-LAGS; BROAD AB We have investigated the relationship between the X-ray variability amplitude and black hole mass for a sample of 46 radio-quiet active galactic nuclei observed by ASCA. 33 of the objects in our sample exhibited significant variability over a time-scale of similar to 40 ks. We determined the normalized excess variance in the 2-10 keV light curves of these objects and found a significant anticorrelation between excess variance and black hole mass. Unlike most previous studies, we have quantified the variability using nearly the same time-scale for all objects. Moreover, we provide a prescription for estimating the uncertainties in variance which accounts both for measurement uncertainties and for the stochastic nature of the variability. We also present an analytical method to predict the excess variance from a model power spectrum accounting for binning, sampling and windowing effects. Using this, we modelled the variance-mass relation assuming all objects have a universal twice-broken power spectrum, with the position of the breaks being dependent on mass. This accounts for the general form of the variance-mass relationship but is formally a poor fit and there is considerable scatter. We investigated this scatter as a function of the X-ray photon index, luminosity and Eddington ratio. After accounting for the primary dependence of excess variance on mass, we find no significant correlation with either luminosity or X-ray spectral slope. We do find an anticorrelation between excess variance and the Eddington ratio, although this relation might be an artefact owing to the uncertainties in the mass measurements. It remains to be established that enhanced X-ray variability is a property of objects with steep X-ray slopes or large Eddington ratios. Narrow-line Seyfert 1 galaxies, in particular, are consistent with being more variable than their broad-line counterparts solely because they tend to have smaller masses. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. Univ Crete, Dept Phys, Iraklion 71003, Crete, Greece. NASA, Explorat Universe Div, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. RP O'Neill, PM (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, Prince Consort Rd, London SW7 2BW, England. EM p.oneill@imperial.ac.uk; k.nandra@imperial.ac.uk; jhep@physics.uoc.gr; turner@lucretia.gsfc.nasa.gov RI Papadakis, Iossif/C-3235-2011 NR 65 TC 68 Z9 68 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 21 PY 2005 VL 358 IS 4 BP 1405 EP 1416 DI 10.1111/j.1365-2966.2005.08860.x PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 913UL UT WOS:000228179000023 ER PT J AU Sun, WB Loeb, NG Lin, B AF Sun, WB Loeb, NG Lin, B TI Light scattering by an infinite circular cylinder immersed in an absorbing medium SO APPLIED OPTICS LA English DT Article ID MIE-SCATTERING; SPHERICAL-PARTICLES; EXTINCTION; SPHERES AB Analytic solutions are developed for the single-scattering properties of an infinite dielectric cylinder embedded in an absorbing medium with normal incidence, which include extinction, scattering and absorption efficiencies, the scattering phase function, and the asymmetry factor. The extinction and scattering efficiencies are derived by the near-field solutions at the surface of the particle. The normalized scattering phase function is obtained by use of the far-field approximation. Computational results show that, although the absorbing medium significantly reduces the scattering efficiency, it has little effect on absorption efficiency. The absorbing medium can significantly change the conventional phase function. The absorbing medium also strongly affects the polarization of the scattered light. However, for large absorbing particles the degrees of polarization change little with the medium's absorption. This implies that, if the transmitting lights are strongly weakened inside the particle, the scattered polarized lights can be used to identify objects even when the absorption property of the host medium is unknown, which is important for both active and passive remote sensing. (c) 2005 Optical Society of America. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hampton Univ, Ctr Atmospher Sci, 21 Langley Blvd,Mail Stop 420, Hampton, VA 23668 USA. EM w.sun@larc.nasa.gov NR 17 TC 24 Z9 25 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 2005 VL 44 IS 12 BP 2338 EP 2342 DI 10.1364/AO.44.002338 PG 5 WC Optics SC Optics GA 919ZX UT WOS:000228657700014 PM 15861840 ER PT J AU Dietrich, M Crenshaw, DM Kraemer, SB AF Dietrich, M Crenshaw, DM Kraemer, SB TI Probing the ionizing continuum of narrow-line Seyfert 1 galaxies. I. Observational results SO ASTROPHYSICAL JOURNAL LA English DT Review DE galaxies : active; galaxies : Seyfert; techniques : spectroscopic ID ACTIVE GALACTIC NUCLEI; X-RAY PROPERTIES; QUASI-STELLAR OBJECTS; OPTICAL-EMISSION-LINE; ACCRETION DISK; PHYSICAL CONDITIONS; CYGNUS X-1; NGC 4151; REGION; SPECTRA AB We present optical spectra and emission-line ratios of 12 narrow-line Seyfert 1 (NLS1) galaxies that we observed to study the ionizing EUV continuum. A common feature in the EUV continuum of active galactic nuclei is the big blue bump (BBB), generally associated with thermal accretion disk emission. While Galactic absorption prevents direct access to the EUV range, it can be mapped by measuring the strength of a variety of forbidden optical emission lines that respond to different EUV continuum regions. We find that narrow emission line ratios involving [O II] lambda 3727, H beta, [O III] lambda 5007, [O I] lambda 6300, H alpha, [N II] lambda 6583, and [S II] lambda lambda 6716, 6731 indicate no significant difference between NLS1 galaxies and broad-line Seyfert 1 (BLS1) galaxies, which suggests that the spectral energy distributions of their ionizing EUV-soft X-ray continua are similar. The relative strength of important forbidden high-ionization lines like [Ne V] lambda 3426 compared to He II lambda 4686 and the relative strength of [Fe X] lambda 6374 appear to show the same range as in BLS1 galaxies. However, a trend of weaker F([O I] lambda 6300)/F(H alpha) emission-line ratios is indicated for NLS1 galaxies compared to BLS1 galaxies. To recover the broad emission line profiles, we used Gaussian components. This approach indicates that the broad H beta profile can be well described with a broad component (FWHM similar or equal to 3275 +/- 800 km s(-1)) and an intermediate broad component (FWHM similar or equal to 1200 +/- 300 km s(-1)). The width of the broad component is in the typical range of normal BLS1 galaxies. The emission-line flux that is associated with the broad component in these NLS1 galaxies amounts to at least 60% of the total flux. Thus, it dominates the total line flux, similar to BLS1 galaxies. C1 Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Ohio State Univ, Dept Astron, McPherson Lab 4055, Columbus, OH 43210 USA. Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dietrich, M (reprint author), Georgia State Univ, Dept Phys & Astron, 1 Pk Pl S SE, Atlanta, GA 30303 USA. EM dietrich@astronomy.ohio-state.edu NR 105 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 700 EP 720 DI 10.1086/429121 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500009 ER PT J AU Postman, M Franx, M Cross, NJG Holden, B Ford, HC Illingworth, GD Goto, T Demarco, R Rosati, P Blakeslee, JP Tran, KV Benitez, N Clampin, M Hartig, GF Homeier, N Ardila, DR Bartko, F Bouwens, RJ Bradley, LD Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Feldman, PD Golimowski, DA Gronwall, C Infante, L Kimble, RA Krist, JE Lesser, MP Martel, AR Mei, S Menanteau, F Meurer, GR Miley, GK Motta, V Sirianni, M Sparks, WB Tran, HD Tsvetanov, ZI White, RL Zheng, W AF Postman, M Franx, M Cross, NJG Holden, B Ford, HC Illingworth, GD Goto, T Demarco, R Rosati, P Blakeslee, JP Tran, KV Benitez, N Clampin, M Hartig, GF Homeier, N Ardila, DR Bartko, F Bouwens, RJ Bradley, LD Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Feldman, PD Golimowski, DA Gronwall, C Infante, L Kimble, RA Krist, JE Lesser, MP Martel, AR Mei, S Menanteau, F Meurer, GR Miley, GK Motta, V Sirianni, M Sparks, WB Tran, HD Tsvetanov, ZI White, RL Zheng, W TI The morphology-density relation in z similar to 1 clusters SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : evolution; galaxies : formation; galaxies : structure ID HUBBLE-SPACE-TELESCOPE; HIGH-REDSHIFT CLUSTERS; COLOR-MAGNITUDE RELATION; STAR-FORMATION RATE; X-RAY; GALAXY CLUSTER; DISK GALAXIES; ADVANCED CAMERA; RICH CLUSTERS; S0 GALAXIES AB We measure the morphology-density relation (MDR) and morphology-radius relation (MRR) for galaxies in seven z similar to 1 clusters that have been observed with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope. Simulations and independent comparisons of our visually derived morphologies indicate that ACS allows one to distinguish between E, S0, and spiral morphologies down to z(850) = 24, corresponding to L/L* 0.21 and 0.30 at z = 0.83 and 1.24, respectively. We adopt density and radius estimation methods that match those used at lower redshift in order to study the evolution of the MDR and MRR. We detect a change in the MDR between 0: 8 < z < 1.2 and that observed at z similar to 0, consistent with recent work; specifically, the growth in the bulge-dominated galaxy fraction, f(E+S0), with increasing density proceeds less rapidly at z similar to 1 than it does at z similar to 0. At z similar to 1 and Sigma >= 500 galaxies Mpc(-2), we find < f(E+S0)> = 0.72 +/- 0.10. At z similar to 0, an E + S0 population fraction of this magnitude occurs at densities about 5 times smaller. The evolution in the MDR is confined to densities Sigma greater than or similar to 40 galaxies Mpc(-2) and appears to be primarily due to a deficit of S0 galaxies and an excess of Sp+Irr galaxies relative to the local galaxy population. The f(E)-density relation exhibits no significant evolution between z = 1 and 0. We find mild evidence to suggest that the MDR is dependent on the bolometric X-ray luminosity of the intracluster medium. Implications for the evolution of the disk galaxy population in dense regions are discussed in the context of these observations. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. European So Observ, D-85748 Garching, Germany. ETH, Inst Astron, CH-8093 Zurich, Switzerland. CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Bartko Sci & Technol, Brighton, CO 80602 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. MetaJiva Sci, Edmonds, WA 98026 USA. Conceptual Analyt LLC, Glenn Dale, MD 20769 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. WM Keck Observ, Kamuela, HI 96743 USA. RP Postman, M (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI White, Richard/A-8143-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012; OI Benitez, Narciso/0000-0002-0403-7455; Blakeslee, John/0000-0002-5213-3548 NR 87 TC 233 Z9 233 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 721 EP 741 DI 10.1086/428881 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500010 ER PT J AU Laurent, GT Aguirre, JE Glenn, J Ade, PAR Bock, JJ Edgington, SF Goldin, A Golwala, SR Haig, D Lange, AE Maloney, PR Mauskopf, PD Nguyen, H Rossinot, P Sayers, J Stover, P AF Laurent, GT Aguirre, JE Glenn, J Ade, PAR Bock, JJ Edgington, SF Goldin, A Golwala, SR Haig, D Lange, AE Maloney, PR Mauskopf, PD Nguyen, H Rossinot, P Sayers, J Stover, P TI The Bolocam Lockman Hole millimeter-wave galaxy survey: Galaxy candidates and number counts SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : high-redshift; galaxies : starburst; submillimeter ID SUBMILLIMETER-SELECTED GALAXIES; SPECTRAL ENERGY-DISTRIBUTION; CLERK-MAXWELL-TELESCOPE; STAR-FORMATION HISTORY; HUBBLE-DEEP-FIELD; REDSHIFT DISTRIBUTION; LIKELIHOOD ESTIMATION; SPITZER OBSERVATIONS; STARBURST GALAXIES; SCUBA-8-MJY SURVEY AB We present results of a new deep 1.1 mm survey using Bolocam, a millimeter-wavelength bolometer array camera designed for mapping large fields at fast scan rates, without chopping. A map, galaxy candidate list, and derived number counts are presented. This survey encompasses 324 arcmin(2) to an rms noise level (filtered for point sources) of sigma(1.1 mm) similar or equal to 1.4 mJy beam(-1) and includes the entire regions surveyed by the published 8 mJy 850 mu m JCMT SCUBA and 1.2 mm IRAM MAMBO surveys. We reduced the data using a custom software pipeline to remove correlated sky and instrument noise via a principal component analysis. Extensive simulations and jackknife tests were performed to confirm the robustness of our source candidates and estimate the effects of false detections, bias, and completeness. In total, 17 source candidates were detected at a significance >= 3.0 sigma, with six expected false detections. Nine candidates are new detections, while eight candidates have coincident SCUBA 850 mu m and/or MAMBO 1.2 mm detections. From our observed number counts, we estimate the underlying differential number count distribution of submillimeter galaxies and find it to be in general agreement with previous surveys. Modeling the spectral energy distributions of these submillimeter galaxies after observations of dusty nearby galaxies suggests extreme luminosities of L = (1.0-1.6) x 10(13) L-circle dot and, if powered by star formation, star formation rates of 500-800 M-circle dot yr(-1). C1 Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Cardiff Univ, Cardiff CF24 3YB, S Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. RP Laurent, GT (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, 593 UCB, Boulder, CO 80309 USA. EM glaurent@colorado.edu NR 65 TC 95 Z9 95 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 742 EP 762 DI 10.1086/428823 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500011 ER PT J AU Ghosh, KK Swartz, DA Tennant, AF Wu, KW Saripalli, L AF Ghosh, KK Swartz, DA Tennant, AF Wu, KW Saripalli, L TI A multiwavelength study of the X-ray sources in NGC 5018 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 5018); X-rays : galaxies ID EARLY-TYPE GALAXIES; ELLIPTIC GALAXIES; NEARBY GALAXIES; STAR-FORMATION; SIMULTANEOUS RADIO; SOURCE POPULATIONS; DISTANT GALAXIES; CLUSTER SYSTEM; BLACK-HOLES; CHANDRA AB The E3 giant elliptical galaxy NGC 5018 was observed with the Chandra X-Ray Observatory's Advanced CCD Imaging Spectrometer for 30 ks on 2001 April 14. Results of the analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are intrinsic to NGC 5018, then all six nonnuclear sources have luminosities exceeding 1039 ergs s(-1) in the 0.5 - 8.0 keV energy band, placing them in the class of ultraluminous X-ray sources. Comparison of X-ray source positions to archival Hubble Space Telescope Wide Field Planetary Camera 2 (HST WFPC2) images reveals that four of the six nonnuclear sources are spatially coincident with bright, MV P less than or similar to -8.6 mag objects. These four objects have optical magnitudes and ( V - I) colors consistent with globular clusters in NGC 5018, but they also have X-ray - to - optical flux ratios consistent with background active galactic nuclei (AGNs). Strong, unpolarized radio emission has been detected from one of the optically bright counterparts. Another optically bright counterpart was observed to vary by similar to 1 mag in optical observations taken on 1997 July 28 and 1999 February 4. Extended X-ray emission is detected within an similar to 15 '' radius of the galaxy center at a luminosity of similar to 10(40) ergs s(-1) in the X-ray band. Its thermal X-ray spectrum (kT similar to 0.4 keV) and its spatial coincidence with strong H alpha emission are consistent with a hot gas origin. The nucleus itself may be a weak X-ray source, L(X) less than or similar to 3.5 x 10(39) ergs s(-1), which displays a radio spectrum typical of AGNs. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35805 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Commonwealth Sci & Ind Res Org, Australia Telescope Natl Facil, Narrabri, NSW 2390, Australia. RP Ghosh, KK (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD50, Huntsville, AL 35805 USA. RI Saripalli, Lakshmi/D-4878-2012; Astronomy & Astrophysics Group, Raman Res Institute/D-4046-2012 NR 51 TC 9 Z9 9 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 815 EP 825 DI 10.1086/428939 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500015 ER PT J AU Bradford, CM Stacey, GJ Nikola, T Bolatto, AD Jackson, JM Savage, ML Davidson, JA AF Bradford, CM Stacey, GJ Nikola, T Bolatto, AD Jackson, JM Savage, ML Davidson, JA TI Warm molecular gas traced with CO J=7 -> 6 in the Galaxy's central 2 parsecs: Dynamical heating of the circumnuclear disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : center; Galaxy : nucleus; ISM : molecules; turbulence ID CLUMPY PHOTODISSOCIATION REGIONS; MAGNETOHYDRODYNAMIC SHOCK-WAVES; FAR-INFRARED OBSERVATIONS; GALACTIC-CENTER REGION; LINE EMISSION; IONIZED-GAS; NEUTRAL-GAS; SUBMILLIMETER EMISSION; ROTATIONAL-EXCITATION; THERMAL BALANCE AB We present an 11 '' resolutionmap of the central 2 pc of the Galaxy in the CO J = 7 --> 6 rotational transition. The CO emission shows rotation about Sgr A* but also evidence for noncircular turbulent motion and a clumpy morphology. We combine our data set with available CO measurements to model the physical conditions in the disk. We find that the molecular gas in the region is both warm and dense, with T similar to 200 300 K and n(H2) similar to (5-7) x 10(4) cm(-3). The mass of warm molecular gas we measure in the central 2 pc is at least 2000 M-., about 20 times the UV-excited atomic gas mass, ruling out a UV heating scenario for the molecular material. We compare the available spectral tracers with theoretical models and conclude that molecular gas is heated with magnetohydrodynamic shocks with v similar to 10-20 km s(-1) and B similar to 0.3-0.5 mG. Using the conditions derived with the CO analysis, we include the other important coolants, neutral oxygen and molecular hydrogen, to estimate the total cooling budget of the molecular material. We derive a mass-to-luminosity ratio of similar to 2 - 3 M-. L-.(-1) , which is consistent with the total power dissipated via turbulent decay in 0.1 pc cells with v(rms) similar to 15 km s(-1). These size and velocity scales are comparable to the observed clumping scale and the velocity dispersion. At this rate, the material near Sgr A* is dissipating its orbital energy on an orbital timescale and cannot last for more than a few orbits. Our conclusions support a scenario in which the features near Sgr A* such as the circumnuclear disk and northern arm are generated by infalling clouds with low specific angular momentum. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA. NASA, Ames Res Ctr, USRA SOFIA, Moffett Field, CA 94035 USA. RP Bradford, CM (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-507, Pasadena, CA 91109 USA. EM matt.bradford@jpl.nasa.gov NR 77 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 866 EP 876 DI 10.1086/428659 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500019 ER PT J AU Cushing, MC Rayner, JT Vacca, WD AF Cushing, MC Rayner, JT Vacca, WD TI An infrared spectroscopic sequence of M, L, and T dwarfs SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : fundamental parameters; stars : individual (2MASS J2224381-0158521); stars : late-type; stars : low-mass, brown dwarfs ID DIGITAL SKY SURVEY; LOW-MASS STARS; COLLISION-INDUCED ABSORPTION; BROWN DWARF; SPECTRAL CLASSIFICATION; MEDIUM-RESOLUTION; MAIN-SEQUENCE; WATER-VAPOR; MODEL ATMOSPHERES; TEMPERATURE SCALE AB We present a 0.6 - 4.1 mu m spectroscopic sequence of M, L, and T dwarfs. The spectra have R = lambda/Delta lambda approximate to 2000 from 0.9 to 2.4 mu m and R = 2500 200 from 2.9 to 4.1 mu m. These new data nearly double the number of L and T dwarfs that have reported L-band spectra. The near-infrared spectra are combined with previously published red-optical spectra to extend the wavelength coverage to similar to 0.6 mu m. Prominent atomic and molecular absorption features are identified including neutral lines of Al, Fe, Mg, Ca, Ti, Na, and K and 19 new weak CH(4) absorption features in the H-band spectra of mid- to late-type T dwarfs. In addition, we detect for the first time the 0 - 0 band of the A (4)Pi - X(4)Sigma(-) transition of VO at similar to 1.06 mu m in the spectra of L dwarfs and the P- and R-branches of the nu(3) band of CH4 in the spectrum of a T dwarf. The equivalent widths of the refractory atomic features all decrease with increasing spectral type and are absent by a spectral type of similar to L0, except for the 1.189 mu mFe I line, which persists to at least similar to L3. We compute the bolometric luminosities of the dwarfs in our sample with measured parallaxes and find good agreement with previously published results that use L'-band photometry to account for the flux emitted from 2.5 to 3.6 mu m. Finally, 2MASS J2224381 - 0158521 (L4.5) has an anomalously red spectrum and the strongest Delta nu = +2 CO bands in our sample. This may be indicative of unusually thick condensate clouds and/or low surface gravity. C1 NASA, SETI Inst, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, SOFIA, USRA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cushing, MC (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. EM mcushing@arizona.edu; rayner@ifa.hawaii.edu; wvacca@mail.arc.nasa.gov NR 96 TC 342 Z9 343 U1 0 U2 11 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 1115 EP 1140 DI 10.1086/428040 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500041 ER PT J AU Cane, HV Erickson, WC AF Cane, HV Erickson, WC TI Solar type II radio bursts and IP type II events SO ASTROPHYSICAL JOURNAL LA English DT Article DE shock waves; Sun : coronal mass ejections (CMEs); Sun : radio radiation ID CORONAL MASS EJECTIONS; INTERPLANETARY SHOCKS; WIND SPACECRAFT; EMISSION; FLARES; WAVES; ACCELERATION; DYNAMICS; ORIGIN AB We have examined radio data from the WAVES experiment on the Wind spacecraft in conjunction with ground-based data in order to investigate the relationship between the shocks responsible for metric type II radio bursts and the shocks in front of coronal mass ejections (CMEs). The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below similar to 4 MHz; such emissions were previously called IP type II events. In contrast, metric type II bursts are usually narrowbanded and display two harmonically related bands. In addition to displaying complete dynamic spectra for a number of events, we also analyze the 135 WAVES 1 - 14 MHz slow-drift time periods in 2001 - 2003. We find that most of the periods contain multiple phenomena, which we divide into three groups: metric type II extensions, IP type II events, and "blobs and bands.'' About half of the WAVES listings include probable extensions of metric type II radio bursts, but in more than half of these events, there were also other slow-drift features. In the 3 yr study period, there were 31 IP type II events; these were associated with the very fastest CMEs. The most common form of activity in the WAVES events, blobs and bands in the frequency range between 1 and 8 MHz, fall below an envelope consistent with the early signatures of an IP type II event. However, most of this activity lasts only a few tens of minutes, whereas IP type II events last for many hours. In this study we find many examples in the radio data of two shock-like phenomena with different characteristics that occur simultaneously in the metric and decametric/hectometric bands, and no clear example of a metric type II burst that extends continuously down in frequency to become an IP type II event. The simplest interpretation is that metric type II bursts, unlike IP type II events, are not caused by shocks driven in front of CMEs. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas 7005, Australia. Bruny Isl Radio Spectrometer, Lunawanna, Tas 7150, Australia. RP Cane, HV (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 37 TC 54 Z9 56 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP 1180 EP 1194 DI 10.1086/428820 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GU UT WOS:000228445500045 ER PT J AU Miller, NA Mushotzky, RF Neff, SG AF Miller, NA Mushotzky, RF Neff, SG TI Radio emission associated with the ultraluminous X-ray source in Holmberg II SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Holmberg II); radio continuum : galaxies; stars : individual (Holmberg II X-1); X-rays : galaxies ID HIGH-RESOLUTION IMAGER; STARBURST GALAXIES; STAR-CLUSTERS; BLACK-HOLES; REMNANTS; NUCLEI; LINE; X-1 AB We report the detection of radio emission coincident with the ultraluminous X-ray source (ULX) in Holmberg II. The radio emission is diffuse and resolved, covering an area similar to 60 x 40 pc in extent and well matched to the recently discovered He II nebula surrounding the X-ray source. Comparison of the radio and optical properties of this extended radio emission argue against its association with either an H II region or a supernova remnant. This is additional evidence that this ULX is not powered by a stellar mass object whose emission is relativistically beamed toward the observer, and thus is either a super-Eddington source or an intermediate-mass black hole as suggested by optical observations. Implications of this result to future and existing radio studies of ULXs are discussed. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Miller, NA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 34 TC 47 Z9 48 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 2005 VL 623 IS 2 BP L109 EP L112 DI 10.1086/430112 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GV UT WOS:000228445600012 ER PT J AU Mills, MJ Toon, OB Vaida, V Hintze, PE Kjaergaard, HG Schofield, DP Robinson, TW AF Mills, MJ Toon, OB Vaida, V Hintze, PE Kjaergaard, HG Schofield, DP Robinson, TW TI Photolysis of sulfuric acid vapor by visible light as a source of the polar stratospheric CN layer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BALLOON-BORNE MEASUREMENTS; ABSORPTION CROSS-SECTIONS; CONDENSATION NUCLEI; MIDDLE ATMOSPHERE; PARTICLE FORMATION; AEROSOL FORMATION; BAND INTENSITIES; NUMERICAL-MODEL; ANTARCTICA; OZONE AB [1] We present the first microphysical calculations confirming that photolysis of sulfuric acid vapor by visible light is responsible for the formation of the springtime "CN layer'' observed in the polar stratosphere. Our calculations show that the recently proposed photolysis mechanism is also sufficient to explain observations of vertically increasing SO2 mixing ratios in the upper stratosphere. Such photolysis, however, does not sufficiently explain the limited observations above 40 km of vertically decreasing H2SO4 and SO3 vapor, suggesting an additional loss mechanism there. We rule out previous speculation regarding reaction of H2SO4 with O(D-1) or OH as inconsistent with observations of SO2. Rather, the loss is consistent with a permanent sink for sulfur, such as H2SO4 neutralization by metals on meteoritic dust. In light of such removal, H2SO4 photolysis to SO2 gains added importance in preserving gaseous sulfur in the upper stratosphere. We also present new cross sections derived from ab initio calculations for H2SO4 absorption at visible and Lyman-alpha wavelengths and evaluate their atmospheric implications. Our atmospheric model reveals that photolysis of H2SO4 by Lyman-alpha radiation is responsible for up to one third of the SO2 in the mesosphere and 10% of the particles in the polar stratospheric CN layer. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NASA, Kennedy Space Ctr, Kennedy Space Ctr, FL 32951 USA. Univ Otago, Dept Chem, Dunedin, New Zealand. RP Mills, MJ (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. EM mills@colorado.edu RI Mills, Michael/B-5068-2010; Kjaergaard, Henrik /H-4333-2014; Vaida, Veronica/N-6069-2014 OI Mills, Michael/0000-0002-8054-1346; Kjaergaard, Henrik /0000-0002-7275-8297; Vaida, Veronica/0000-0001-5863-8056 NR 39 TC 48 Z9 48 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 2005 VL 110 IS D8 AR D08201 DI 10.1029/2004JD005519 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 922QG UT WOS:000228852200011 ER PT J AU Wang, DY von Clarmann, T Fischer, H Funke, B Gil-Lopez, S Glatthor, N Grabowski, U Hopfner, M Kaufmann, M Kellmann, S Kiefer, M Koukouli, ME Linden, A Lopez-Puertas, M Tsidu, GM Milz, M Steck, T Stiller, GP Simmons, AJ Dethof, A Swinbank, R Marquardt, C Jiang, JH Romans, LJ Wickert, J Schmidt, T Russell, J Remsberg, E AF Wang, DY von Clarmann, T Fischer, H Funke, B Gil-Lopez, S Glatthor, N Grabowski, U Hopfner, M Kaufmann, M Kellmann, S Kiefer, M Koukouli, ME Linden, A Lopez-Puertas, M Tsidu, GM Milz, M Steck, T Stiller, GP Simmons, AJ Dethof, A Swinbank, R Marquardt, C Jiang, JH Romans, LJ Wickert, J Schmidt, T Russell, J Remsberg, E TI Validation of stratospheric temperatures measured by michelson interferometer for passive atmospheric sounding (MIPAS) on envisat SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; LIMB EMISSION-SPECTRA; RADIO OCCULTATION; PROFILES; RETRIEVAL; CHAMP; MIPAS/ENVISAT; MIDDLE; WINTER AB [1] The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the Envisat satellite provides temperature and various gas profiles from limb-viewing midinfrared emission measurements. The stratospheric temperatures retrieved at the Institut fur Meteorologie und Klimaforschung (IMK) for September/October 2002 and October/November 2003 are compared with a number of reference data sets, including global radiosonde (RS) observations, radio occultation (RO) measurements of Global Positioning System (GPS) on German Challenging Minisatellite Payload ( CHAMP) and Argentinean Satelite de Aplicaciones Cientificas-C (SAC-C) satellite, Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS), and the analyses of European Centre for Medium-Range Weather Forecasts (ECMWF) and Met Office (METO), United Kingdom. The data sets show a good general agreement. Between 10 and 30 km altitude the mean differences are within +/- 0.5 K for the averages over the height interval and within +/-( 1 - 1.5) K at individual levels for comparisons with RS, GPS-RO/CHAMP, and SAC-C, ECMWF, and METO. Between 30 and 45 km the MIPAS mean temperatures, averaged over the height region, are higher than ECMWF but lower than METO by similar to 1.5 K, while they differ by +/- 0.5 K with respect to HALOE, with maximum discrepancies of similar to 2.5 K peaking around 35 km. Between 45 and 50 km, MIPAS temperatures show a low bias compared to HALOE, ECMWF, and METO with mean differences of - 1 to - 3 K and with a better agreement with HALOE. The large discrepancies between MIPAS and the analyses above 30 km likely suggest deficiency in the underlying general circulation models. The standard deviations vary between 2.5 and 3.5 K for individual data sets, with more than 70% being contributed from the expected variability of the atmosphere. Retrieved temperatures with accuracy of similar to 0.5 - 1 K after removing the atmospheric variability provide highly accurate knowledge to characterize our environment. C1 Forschungszentrum Karlsruhe, Inst Meteorol & Klimaforsch, D-76021 Karlsruhe, Germany. Univ Karlsruhe, Inst Meteorol & Klimaforsch, D-76021 Karlsruhe, Germany. CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. Met Off, Exeter EX1 3PB, Devon, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Geoforschungszentrum Potsdam, Dept Geodesy & Remote Sensing 1, D-14473 Potsdam, Germany. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sci Applicat Int Corp, Gen Sci Operat, MODIS Characterizat Support Team, 7501 Forbes Blvd,Suite 103, Seabrook, MD 20706 USA. EM ding.yi.wang@saicmodis.com RI Milz, Mathias/C-9899-2011; Koukouli, MariLiza/A-2249-2015; Kaufmann, Martin/A-3905-2013; Schmidt, Torsten/A-7142-2013; Hopfner, Michael/A-7255-2013; Stiller, Gabriele/A-7340-2013; von Clarmann, Thomas/A-7287-2013; Glatthor, Norbert/B-2141-2013; Kiefer, Michael/A-7254-2013; Wickert, Jens/A-7257-2013; Lopez Puertas, Manuel/M-8219-2013; Funke, Bernd/C-2162-2008 OI Koukouli, MariLiza/0000-0002-7509-4027; Schmidt, Torsten/0000-0001-9302-1000; Hopfner, Michael/0000-0002-4174-9531; Stiller, Gabriele/0000-0003-2883-6873; von Clarmann, Thomas/0000-0003-2219-3379; Lopez Puertas, Manuel/0000-0003-2941-7734; Funke, Bernd/0000-0003-0462-4702 NR 34 TC 13 Z9 13 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 2005 VL 110 IS D8 AR D08301 DI 10.1029/2004JD005342 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 922QG UT WOS:000228852200007 ER PT J AU French, BL Davis, LM Munzinger, ES Slavin, JWJ Christy, PC Thompson, DW Southward, RE AF French, BL Davis, LM Munzinger, ES Slavin, JWJ Christy, PC Thompson, DW Southward, RE TI Palladium-polyimide nanocomposite membranes: Synthesis and characterization of reflective and electrically conductive surface-metallized films SO CHEMISTRY OF MATERIALS LA English DT Article ID SITU SILVER(I) REDUCTION; SINGLE-STAGE SYNTHESIS; POLYMER MEMBRANES; COMPLEXES; MATRIX; CLUSTERS; DEPOSITION; MONOLAYERS; PARTICLES; ADHESION AB Palladium-surface-metallized polyimide films were prepared by an unusual macromolecular-matrix-mediated, single-stage synthetic protocol first reported by Taylor et al. (J. Am. Chem. Soc. 1980, 102, 876). Several Pd(II) complexes, [PdCl2(SMe2)(2)], [PdBr2(SMe2)(2)], and Pd(CF3COO)(2), were dissolved in the poly(amic acid)s of 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA)/4,4'-oxydianiline (4,4'-ODA) and 3,3'-diaminobenzophenone (BPDA)/4,4'-ODA in the solvent dimethylacetamide. Films cast onto glass plates from these Pd(II)-doped resins were thermally cured to 300 degrees C in air, which resulted in air-side surface-metallized membranes. The films were characterized by both specular and diffuse reflectivity and by conductivity measurements as a function of the cure time and temperature. Maximum specular reflectivities of ca. 50% were observed at 530 nm. After maximum specular reflectivities were achieved in the thermal cure cycle at 300 degrees C from 0.5 to 2 h, the film surface quickly degraded upon further curing. The surface sheet resistivities were in the range of ca. 1-75 Omega/square. Initial Pd metal particles formed in the film were in the 3-10 nm range. The optical data coupled SEM micrographs, elemental analytical results, and X-ray diffraction observations were interpreted to support a mechanism for the formation of a reflective and conductive metallized surface which involves selective air-side surface oxidative degradation of the polyimide matrix to volatile products, which then concentrates the metal nanoparticles at the surface and increases the particle size via sintering. The mechanical properties of the metallized films are compromised with respect to the parent polyimide although the composite membranes are still useful for a range of applications. The tensile strength is reduced; the percent elongation and the tensile modulus are increased. Both BTDA/ODA and BPDA/ODA gave very similar results with the Pd(II) additives. Many Pd(II) compounds, e.g., PdBr2, were not useful in generating a metallized surface, which suggests that the pathway to a metallized surface is extremely sensitive to the experimental conditions. C1 Coll William & Mary, Dept Chem, Williamsburg, VA 23185 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23185 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Thompson, DW (reprint author), Coll William & Mary, Dept Chem, Williamsburg, VA 23185 USA. NR 47 TC 19 Z9 19 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD APR 19 PY 2005 VL 17 IS 8 BP 2091 EP 2100 DI 10.1021/cm040378m PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 917BU UT WOS:000228431700028 ER PT J AU Brandon, AD Walker, RJ AF Brandon, AD Walker, RJ TI The debate over core-mantle interaction SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Pt-Re-Os; Hf-W; mantle isotope systematics; core-mantle boundary ID OS ISOTOPE SYSTEMATICS; HIGHLY SIDEROPHILE ELEMENTS; CONVERGENT PLATE MARGIN; OCEANIC ISLAND BASALTS; RE-OS; EARTHS CORE; IRON-METEORITES; HAWAIIAN PICRITES; GORGONA ISLAND; RE-187-OS-187 SYSTEMATICS AB Some hotspot volcanism is likely the surface manifestation of hot upwelling mantle plumes that rise from the core-mantle boundary (CMB) or from compositional boundaries within the mantle. Plumes that rise from the CMB may generate magmas that carry compositional information about the diversity of materials present in the lowermost mantle. Some plume-derived materials have coupled enrichments in Os-186/Os-188 and Os-187/Os-188 relative to upper mantle materials. The coupled enrichments are consistent with Os isotopic compositions predicted for the liquid outer core that might result from elevated Pt/Os and Re/Os generated via progressive crystallization of a solid inner core over Earth history. If these enrichments are a reflection of coremantle interaction, then the mechanisms of material transport between the core and the mantle, rates of whole mantle convection at present and over time, and cooling histories for the core and the mantle can potentially be constrained. However, fractionation may also occur between Pt/Re/Os via mantle and crustal processes and in particular, Pt and Pt/Rc may be elevated in some portions of ancient recycled slabs thought to be present in certain plume sources. This possibility brings into question whether the coupled Os isotope enrichments are a product of core-mantle exchange. Hence, a lively debate over the causes of Os isotopic heterogeneities in plume-derived materials has ensued. Resolution of this debate has been hampered by limited constraints on the behavior of these elements in the Earth's core, mantle and crust. A variety of analytical and experimental tasks will have to be pursued to test different aspects of both the core-mantle interaction and crustal recycling models, and to further constrain the behaviors of these elements. These future endeavors may help to unravel the compositional complexities of plumederived materials and their mantle sources, and ultimately provide important insights to processes operating at the CNIB. (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. RP Brandon, AD (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SR, Houston, TX 77058 USA. EM alan.d.brandon1@jsc.nasa.gov RI Walker, Richard/K-6869-2016 OI Walker, Richard/0000-0003-0348-2407 NR 87 TC 104 Z9 111 U1 6 U2 33 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD APR 15 PY 2005 VL 232 IS 3-4 BP 211 EP 225 DI 10.1016/j.epsl.2005.01.034 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 921QP UT WOS:000228779900001 ER PT J AU Cruden, BA Meyyappan, M AF Cruden, BA Meyyappan, M TI Characterization of a radio frequency carbon nanotube growth plasma by ultraviolet absorption and optical emission spectroscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; FOURIER-TRANSFORM SPECTROSCOPY; ELECTRON-IMPACT EXCITATION; FIELD-EMISSION; GAS TEMPERATURE; CROSS-SECTIONS; DIAMOND DEPOSITION; NANOFIBER GROWTH; ATOMIC-HYDROGEN; RADIATIVE MODEL AB Radio frequency driven methane/hydrogen plasmas for carbon nanotube growth at pressures between 0.5 and 20 Torr, bias power from 0 to 110 W, and inductive coil power from 0 to 200 W are characterized via optical diagnostics. Ultraviolet absorption spectroscopy is used for quantitative determination of CH3 radical density for these systems, giving densities on the order of 10(13) cm(-3), accounting for approximately 0.1% of the plasma neutral content. Emission data are also analyzed to extract neutral gas temperatures from the H-2 spectrum and electron densities and temperatures and approximate atomic H densities in the system. Neutral temperature is estimated between 700 and 1100 K, though the lower electrode is heated to 1273 K. Electron temperature is estimated to be between 2.5 and 3.5 eV in the high-energy (>12 eV) portion of the electron energy distribution, and the data suggest an overall non-Maxwellian distribution of electrons. The dissociation of hydrogen is estimated at around 0.1%. Dependencies on power and pressure are explored, indicating more efficient ionization, dissociation, and electron heating at lower pressure and higher power. The absence of any dependency on coil power suggests the plasma is operating in a noninductive mode for these conditions. (C) 2005 American Institute of Physics. C1 NASA, Ctr Nanotechnol, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruden, BA (reprint author), NASA, Ctr Nanotechnol, Ames Res Ctr, Mail Stop 223-2, Moffett Field, CA 94035 USA. EM bcruden@mail.arc.nasa.gov NR 57 TC 14 Z9 14 U1 1 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 2005 VL 97 IS 8 AR 084311 DI 10.1063/1.1865315 PG 11 WC Physics, Applied SC Physics GA 920XT UT WOS:000228729500098 ER PT J AU Li, C Su, CH Lehoczky, SL Scripa, RN Lin, B Ban, H AF Li, C Su, CH Lehoczky, SL Scripa, RN Lin, B Ban, H TI Thermophysical properties of liquid Te: Density, electrical conductivity, and viscosity SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ROTATING MAGNETIC-FIELD; DIRECTIONAL SOLIDIFICATION; NEUTRON-SCATTERING; HGZNTE ALLOY; TELLURIUM; GROWTH; SYSTEM; HGCDTE AB The thermophysical properties of liquid Te, namely, density, electrical conductivity, and viscosity, were determined using the pycnometric and transient torque methods from the melting point of Te (723 K) to approximately 1150 K. A maximum was observed in the density of liquid Te as the temperature was increased. The electrical conductivity of liquid Te increased to a constant value of 2.9x10(5) Omega(-1) m(-1) as the temperature was raised above 1000 K. The viscosity decreased rapidly upon heating the liquid to elevated temperatures. The anomalous behaviors of the measured properties are explained as caused by the structural transitions in the liquid and discussed in terms of Eyring's [A. I. Gubanov, Quantum Electron Theory of Amorphous Conductors (Consultants Bureau, New York, 1965)] and Bachinskii's [Zh. Fiz.-Khim. O-va. 33, 192 (1901)] predicted behaviors for homogeneous liquids. The properties were also measured as a function of time after the liquid was cooled from approximately 1173 or 1123 to 823 K. No relaxation phenomena were observed in the properties after the temperature of liquid Te was decreased to 823 K, in contrast to the relaxation behavior observed for some of the Te compounds. (C) 2005 American Institute of Physics. C1 NASA, Micrograv Sci & Applicat Dept, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Mat Sci & Engn, Birmingham, AL 35294 USA. Univ Alabama, Dept Mech Engn, Birmingham, AL 35294 USA. RP Li, C (reprint author), NASA, Micrograv Sci & Applicat Dept, George C Marshall Space Flight Ctr, SD 46, Huntsville, AL 35812 USA. EM chao.li@msfc.nasa.gov RI Ban, Heng/I-6268-2012 NR 43 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 2005 VL 97 IS 8 AR 083513 DI 10.1063/1.1868881 PG 7 WC Physics, Applied SC Physics GA 920XT UT WOS:000228729500018 ER PT J AU Pietrogrande, MC Zampolli, MG Dondi, F Szopa, C Sternberg, R Buch, A Raulin, F AF Pietrogrande, MC Zampolli, MG Dondi, F Szopa, C Sternberg, R Buch, A Raulin, F TI In situ analysis of the Martian soil by gas chromatography: Decoding of complex chromatograms of organic molecules of exobiological interest SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article; Proceedings Paper CT 27th International Symposium on Capillary Chromatography CY MAY 31-JUN 04, 2004 CL Riva del Garda, ITALY DE carboxylic acids; Martian soil; chemometric method ID MULTICOMPONENT CHROMATOGRAMS; FOURIER-ANALYSIS; COMETARY NUCLEUS; SPACE MISSIONS; TITANS ATMOSPHERE; ISOTHERMAL CHROMATOGRAMS; MASS-SPECTROMETRY; AMINO-ACIDS; MARS; BUTYLDIMETHYLSILYL AB Gas chromatography-mass spectrometry (GC-MS) will be used in future space exploration missions, in order to seek organic molecules at the surface of Mars, and especially potential chemical indicators of life. Carboxylic acids are among the most expected organic species at the surface of Mars, and they could be numerous in the analysed samples. For this reason, a chemometric method was applied to support the interpretation of chromatograms of carboxylic acid mixtures. The method is based on AutoCovariance Function (ACVF) in order to extract information on the sample - number and chemical structure of the components - and on separation performance. The procedure was applied to standard samples containing targeted compounds which are among the most expected to be present in the Martian soil: n-alkanoic and benzene dicarboxylic acids. ACVF was computed on the obtained chromatograms and plotted versus retention time: peaks of the ACVF plot can be related to specific molecular structures and are diagnostic for chemical identification of compounds. (c) 2004 Elsevier B.V. All rights reserved. C1 Univ Ferrara, Dept Chem, I-44100 Ferrara, Italy. CNRS, UMR 7620, IPSL, Verrieres Le Buisson, France. CNRS, UMR 7583, LISA, Creteil, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pietrogrande, MC (reprint author), Univ Ferrara, Dept Chem, Via L Borsai 46, I-44100 Ferrara, Italy. EM mpc@unife.it RI szopa, cyril/C-6865-2015; OI szopa, cyril/0000-0002-0090-4056; Pietrogrande, Maria Chiara/0000-0003-1865-6959 NR 41 TC 21 Z9 22 U1 1 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 15 PY 2005 VL 1071 IS 1-2 BP 255 EP 261 DI 10.1016/j.chroma.2004.08.126 PG 7 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 916QS UT WOS:000228401300036 PM 15865201 ER PT J AU Jakob, C Tselioudis, G Hume, T AF Jakob, C Tselioudis, G Hume, T TI The radiative, cloud, and thermodynamic properties of the major tropical western Pacific cloud regimes SO JOURNAL OF CLIMATE LA English DT Article ID ATMOSPHERIC RADIATION; MEASUREMENT PROGRAM; CLIMATE-RESEARCH; MIDLATITUDE; SATELLITE; ISCCP; IDENTIFICATION; CONVECTION; SYSTEMS; MODELS AB This study investigates the radiative, cloud, and thermodynamic characteristics of the atmosphere separated into objectively defined cloud regimes in the tropical we!;tern Pacific (TWP). A cluster analysis is applied to 2 yr of daytime-only data from the International Satellite Cloud Climatology Project (ISCCP) to identify four major cloud regimes in the TWP region. A variety of data collected at the Department of Energy's Atmospheric Radiation Measurement Program (ARM) site on Manus Island is then used to identify the main characteristics of the regimes. Those include surface and top-of-the-atmosphere radiative fluxes and cloud properties derived from a suite of ground-based active remote sensors, as well as the temperature and water vapor distribution measured from radiosondes. The major cloud regimes identified in the TWP area are two suppressed regimes-one dominated by the occurrence of mostly shallow clouds, the other by thin cirrus-as well as two convectively active regimes-one exhibiting a large coverage of optically thin cirrus clouds, If e other characterized by a large coverage with optically thick clouds. All four of these TWP cloud regimes are shown to exist with varying frequency of occurrence at the ARM site at Manus. It is further shown that the detailed data available at that site can be used to characterize the radiative, cloud, and thermodynamic, properties of each of the regimes, demonstrating the potential of the regime separation to facilitate the extrapolation of observations at one location to larger scales. A variety of other potential applications of the regime separation are discussed. C1 BMRC, Melbourne, Vic 3001, Australia. Columbia Univ, NASA, GISS Dept Appl Phys, New York, NY USA. RP Jakob, C (reprint author), BMRC, GPO Box 1289K, Melbourne, Vic 3001, Australia. EM c.jakob@bom.gov.au RI Jakob, Christian/A-1082-2010 OI Jakob, Christian/0000-0002-5012-3207 NR 35 TC 59 Z9 59 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR 15 PY 2005 VL 18 IS 8 BP 1203 EP 1215 DI 10.1175/JCLI3326.1 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 924JM UT WOS:000228975100006 ER PT J AU Larson, J Zhou, YP Higgins, RW AF Larson, J Zhou, YP Higgins, RW TI Characteristics of landfalling tropical cyclones in the United States and Mexico: Climatology and interannual variability SO JOURNAL OF CLIMATE LA English DT Article ID TO-MONTH VARIABILITY; HURRICANE ACTIVITY; EL-NINO; EXTRATROPICAL CIRCULATION; ANNULAR MODES; OSCILLATION; PRECIPITATION; TEMPERATURE; RAINFALL; INTENSE AB The climatology and interannual variability of landfalling tropical cyclones and their impacts on precipitation in the continental United States and Mexico are examined. The analysis is based on National Hurricane Center 6-hourly tropical cyclone track data for the Atlantic and eastern Pacific basins and gridded daily U.S. precipitation data for the period August-October 1950-98. Geographic maps of total tropical cyclone strike days, and the mean and maximum percentage of precipitation due to tropical cyclones, are examined by month. To make the procedures objective, it is assumed that precipitation is symmetric about the storm's center. While this introduces some incertainty in the analysis, sensitivity tests show that this assumption is reasonable for precipitation within 5&DEG; of the circulation center. The relationship between landfalling tropical cyclones and two leading patterns of interannual climate variability-El Nino-Southern Oscillation (ENSO) and the Arctic Oscillation (AO)-are then examined. Relationships between tropical cyclone frequency and intensity and composites of 200-hPa geopotential height and wind shear anomalies are also examined as a function of ENSO phase and AO phase using classifications devised at the Climate Prediction Center. The data show that tropical cyclone activity in the Atlantic basin is modulated on both seasonal and intraseasonal time scales by the AO and ENSO and that impact of the two modes of climate variability is greater together than apart. This suggests that, during La Nina conditions. atmospheric circulation is more conducive to activity in the main development region during AO-positive conditions than during AO-negative ones and that, during El Nino conditions, atmospheric circulation appears even less conducive to tropical cyclone development during the negative phase of the AO than during the positive phase. C1 NOAA NWS NCEP, Climate Predict Ctr, Anal Branch, Camp Springs, MD 20746 USA. Williams Coll, Williamstown, MA 01267 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Higgins, RW (reprint author), NOAA NWS NCEP, Climate Predict Ctr, Anal Branch, Camp Springs, MD 20746 USA. EM wayne.higgins@noaa.gov NR 21 TC 66 Z9 68 U1 3 U2 16 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR 15 PY 2005 VL 18 IS 8 BP 1247 EP 1262 DI 10.1175/JCLI3317.1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 924JM UT WOS:000228975100009 ER PT J AU Palosz, W Volz, M Cobb, S Motakef, S Szofran, FR AF Palosz, W Volz, M Cobb, S Motakef, S Szofran, FR TI Detached growth of germanium by directional solidification SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE Bridgman technique; detached growth; germanium ID BRIDGMAN GROWTH; SURFACE-TENSION; MICROGRAVITY; CRYSTALS; STABILITY; ANGLE; CDTE AB The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al. (c) 2005 Elsevier B.V. All rights reserved. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. BAE Syst AS, Huntsville, AL 35806 USA. Cape Simulat Inc, Natick, MA 01760 USA. RP Palosz, W (reprint author), NASA, Marshall Space Flight Ctr, XD42, Huntsville, AL 35812 USA. EM witold.palosz@msfc.nasa.gov NR 20 TC 24 Z9 25 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR 15 PY 2005 VL 277 IS 1-4 BP 124 EP 132 DI 10.1016/j.jcrysgro.2005.01.078 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 921AZ UT WOS:000228737900019 ER PT J AU Metzger, PT Donahue, CM AF Metzger, PT Donahue, CM TI Elegance of disordered granular packings: A validation of Edward's hypothesis SO PHYSICAL REVIEW LETTERS LA English DT Article ID STATISTICAL-MECHANICS; NUMERICAL-MODEL; STRESS; TRANSMISSION; DYNAMICS; SYSTEMS; MATTER AB We have found a way to analyze Edwards' density of states for static granular packings in the special case of round, rigid, frictionless grains assuming a constant coordination number. It obtains the most entropic density of single grain states, which predicts several observables including the distribution of contact forces. We compare these results against empirical data obtained in dynamic simulations of granular packings. The agreement is quite good, helping validate the use of statistical mechanics methods in granular physics. The differences between theory and empirics are mainly related to the coordination number, and when the empirical data are sorted by that number we obtain several insights that suggest an underlying elegance in the density of states. C1 NASA, KSC Appl Phys Lab, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. Berry Coll, Dept Phys Astron & Geol, Mt Berry, GA 30149 USA. RP Metzger, PT (reprint author), NASA, KSC Appl Phys Lab, John F Kennedy Space Ctr, YA-C3-E, Kennedy Space Ctr, FL 32899 USA. EM Philip.T.Metzger@nasa.gov RI Metzger, Philip/R-3136-2016 OI Metzger, Philip/0000-0002-6871-5358 NR 32 TC 18 Z9 18 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 15 PY 2005 VL 94 IS 14 AR 148001 DI 10.1103/PhysRevLett.94.148001 PG 4 WC Physics, Multidisciplinary SC Physics GA 916MU UT WOS:000228390600063 PM 15904114 ER PT J AU Hook, SJ Dmochowski, JE Howard, KA Rowan, LC Karlstrom, KE Stock, JM AF Hook, SJ Dmochowski, JE Howard, KA Rowan, LC Karlstrom, KE Stock, JM TI Mapping variations in weight percent silica measured from multispectral thermal infrared imagery - Examples from the Hiller Mountains, Nevada, USA and Tres Virgenes-La Reforma, Baja California Sur, Mexico SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE silica; weight percent; infrared imagery; MODIS/ASTER airborne simulator (MASTER) ID SOUTH VIRGIN MOUNTAINS; GOLD BUTTE; NORTHWESTERN ARIZONA; TECTONIC EVOLUTION; CRUSTAL EVOLUTION; GRAND-CANYON; FAULT; CONSTRAINTS; EMISSION; COMPLEX AB Remotely sensed multispectral thermal infrared (8-13 mu m) images are increasingly being used to map variations in surface silicate mineralogy. These studies utilize the shift to longer wavelengths in the main spectral feature in minerals in this wavelength region (reststrahlen band) as the mineralogy changes from felsic to mafic. An approach is described for determining the amount of this shift and then using the shift with a reference curve, derived from laboratory data, to remotely determine the weight percent SiO2 of the surface. The approach has broad applicability to many study areas and can also be fine-tuned to give greater accuracy in a particular study area if field samples are available. The approach was assessed using airborne multispectral thermal infrared images from the Hiller Mountains, Nevada, USA and the Tres Virgenes-La Reforma, Baja California Sur, Mexico. Results indicate the general approach slightly overestimates the weight percent SiO2 of low silica rocks (e.g. basalt) and underestimates the weight percent SiO2 of high silica rocks (e.g. granite). Fine tuning the general approach with measurements from field samples provided good results for both areas with errors in the recovered weight percent SiO2 of a few percent. The map units identified by these techniques and traditional mapping at the Hiller Mountains demonstrate the continuity of the crystalline rocks from the Hiller Mountains southward to the White Hills supporting the idea that these ranges represent an essentially continuous footwall block below a regional detachment. Results from the Baja California data verify the most recent volcanism to be basaltic-andesite. (c) 2005 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. US Geol Survey, Menlo Pk, CA 94025 USA. US Geol Survey, Natl Ctr, Reston, VA 20192 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Hook, SJ (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501, Pasadena, CA 91009 USA. EM Simon.J.Hook@jpl.nasa.gov OI Stock, Joann Miriam/0000-0003-4816-7865 NR 49 TC 34 Z9 37 U1 2 U2 20 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR 15 PY 2005 VL 95 IS 3 BP 273 EP 289 DI 10.1016/j.rse.2004.11.020 PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 914VR UT WOS:000228256600001 ER PT J AU Savchenkov, AA Matsko, AB Strekalov, D Ilchenko, VS Maleki, L AF Savchenkov, AA Matsko, AB Strekalov, D Ilchenko, VS Maleki, L TI Mode filtering in optical whispering gallery resonators SO ELECTRONICS LETTERS LA English DT Article AB A method of suppression of unwanted 'transverse' modes in ultra-high Q optical whispering gallery resonators by use of radiative dampers is proposed and demonstrated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 5 TC 18 Z9 18 U1 0 U2 10 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD APR 14 PY 2005 VL 41 IS 8 BP 495 EP 497 DI 10.1049/el:20058301 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 921FN UT WOS:000228749700029 ER PT J AU Rignot, E Casassa, G Gogineni, S Kanagaratnam, P Krabill, W Pritchard, H Rivera, A Thomas, R Turner, J Vaughan, D AF Rignot, E Casassa, G Gogineni, S Kanagaratnam, P Krabill, W Pritchard, H Rivera, A Thomas, R Turner, J Vaughan, D TI Recent ice loss from the Fleming and other glaciers, Wordie Bay, West Antarctic Peninsula SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MASS-BALANCE; BREAK-UP; SHELVES; RETREAT; SURFACE; DISINTEGRATION; COLLAPSE AB Satellite radar interferometry data from 1995 to 2004, and airborne ice thickness data from 2002, reveal that the glaciers flowing into former Wordie Ice Shelf, West Antarctic Peninsula, discharge 6.8 +/- 0.3 km(3)/yr of ice, which is 84 +/- 30 percent larger than a snow accumulation of 3.7 +/- 0.8 km(3)/yr over a 6,300 km(2) drainage basin. Airborne and ICESat laser altimetry elevation data reveal glacier thinning at rates up to 2 m/yr. Fifty km from its ice front, Fleming Glacier flows 50 percent faster than it did in 1974 prior to the main collapse of Wordie Ice Shelf. We conclude that the glaciers accelerated following ice shelf removal, and have been thinning and losing mass to the ocean over the last decade. This and other observations suggest that the mass loss from the northern part of the Peninsula is not negligible at present. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ctr Estudios Cient, Valdivia, Chile. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hydrospher Proc,EG&G, Wallops Isl, VA 23337 USA. British Antarctic Survey, Cambridge CB3 0E7, England. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 200-321, Pasadena, CA 91109 USA. EM eric.rignot@jpl.nasa.gov; gcasassa@cecs.cl; gogineni@ittc.ku.edu; krabill@osb1.wff.nasa.gov; thomas@aim1.wff.nasa.gov; dgv@bas.ac.uk RI Vaughan, David/C-8348-2011; Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 18 TC 48 Z9 52 U1 0 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 14 PY 2005 VL 32 IS 7 AR L07502 DI 10.1029/2004GL021947 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 917QQ UT WOS:000228480000001 ER PT J AU Rind, D Lerner, J Zawodny, J AF Rind, D Lerner, J Zawodny, J TI A complementary analysis for SAGE II data profiles SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB We present a screened and gridded SAGE II data set, as a complement to the profile data available for the 19 years of records from November 1984 through December 2003. The data screening method is described, and differences between screened and unscreened data are presented. Extensive changes occur in the water vapor data set, which has excessive values in many regions without the screening. Screened NO2 values are larger in the middle stratosphere, for the zonal average by up to 10-15%, and reduced in the lower stratosphere zonally by up to 15-30%, while zonal average ozone values are as much as 20-30% larger in the lower stratosphere and upper troposphere. Many of these changes are due to interference effects from aerosols and clouds, but additional bad data points, isolated by visual inspection, occur for no obvious reason. The screening procedures also remove spurious trends. This data set is available via CD-ROM. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Rind, D (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM drind@giss.nasa.gov NR 5 TC 12 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 14 PY 2005 VL 32 IS 7 AR L07812 DI 10.1029/2005GL022550 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 917QQ UT WOS:000228480000005 ER PT J AU Huang, JP Minnis, P Lin, B Yi, YH Khaiyer, MM Arduini, RF Fan, A Mace, GG AF Huang, JP Minnis, P Lin, B Yi, YH Khaiyer, MM Arduini, RF Fan, A Mace, GG TI Advanced retrievals of multilayered cloud properties using multispectral measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER AMOUNT; MICROWAVE; PARAMETERS; RADIOMETER; LIQUID; OCEANS AB [1] Current satellite cloud retrievals are usually based on the assumption that all clouds consist of a homogenous single layer despite the frequent occurrence of cloud overlap. As such, cloud overlap will cause large errors in the retrievals of many cloud properties. To address this problem, a multilayered cloud retrieval system (MCRS) is developed by combining satellite visible and infrared radiances and surface microwave radiometer measurements. A two-layer cloud model was used to simulate ice-over-water cloud radiative characteristics. The radiances emanating from the combined low cloud and surface are estimated using the microwave liquid water with an assumption of effective droplet size. These radiances replace the background radiances traditionally used in single-layer cloud retrievals. The MCRS is applied to data from March through October 2000 over four Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) sites. The results are compared to the available retrievals of ice water path (IWP) from radar data and show that the MCRS clearly produces a more accurate retrieval of ice-over-water cloud properties. MCRS yields values of IWP that are closest to those from the radar retrieval. For ice-over-water cloud systems, on average, the optical depth and IWP are reduced, from original overestimates, by approximately 30%. The March - October mean cloud effective temperatures from the MCRS are decreased by 10 +/- 12 K, which translates to an average height difference of similar to 1.4 km. These results indicate that ice-cloud height derived from traditional single-layer retrieval is underestimated, and the midlevel ice cloud coverage is over classified. Effective ice crystal particle sizes are increased by only a few percent with the new method. This new physically based technique should be robust and directly applicable when data are available simultaneously from a satellite imager and the appropriate satellite or surface microwave sensor. C1 NASA, Analyt Serv & Mat Inc, Langley Res Ctr, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. SAIC, Hampton, VA 23666 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. RP Huang, JP (reprint author), NASA, Analyt Serv & Mat Inc, Langley Res Ctr, 1 Enterprise Pkwy,Suite 300, Hampton, VA 23666 USA. EM j.huang@larc.nasa.gov RI zhang, zhijuan/H-9917-2016; Minnis, Patrick/G-1902-2010 OI zhang, zhijuan/0000-0002-5328-7506; Minnis, Patrick/0000-0002-4733-6148 NR 23 TC 34 Z9 39 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 13 PY 2005 VL 110 IS D15 AR D15S18 DI 10.1029/2004JD005101 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 917QV UT WOS:000228480600001 ER PT J AU Prigent, C Aires, F Rossow, WB Robock, A AF Prigent, C Aires, F Rossow, WB Robock, A TI Sensitivity of satellite microwave and infrared observations to soil moisture at a global scale: Relationship of satellite observations to in situ soil moisture measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WIND SCATTEROMETER DATA; SPECIAL SENSOR MICROWAVE/IMAGER; HIGH-RESOLUTION RADIOMETER; LAND-SURFACE EMISSIVITIES; ERS-SCATTEROMETER; BIOPHYSICAL VARIABLES; VEGETATION INDEXES; WETNESS PROJECT; TEMPERATURE; MODEL AB [1] This study presents a systematic and integrated analysis of the sensitivity of the available satellite observations to in situ soil moisture measurements. Although none of these satellites is optimized for land surface characterization, before the launches of the SMOS- and HYDROS-dedicated missions they are the only potential sources of global soil moisture measurements. The satellite observations include passive microwave emissivities, active microwave scatterometer data, and infrared estimates of the diurnal amplitude of the surface skin temperature. The Global Soil Moisture Data Bank provides in situ soil moisture measurements in five separate regions. This simultaneous analysis of various satellite observations and the large amount of in situ measurements has two major advantages. First, this analysis helps identify and separate the physical mechanisms that affect the satellite observations. For example, we show that the passive microwave polarization differences at 19 GHz and above are essentially sensitive to the vegetation and not to the soil moisture (i.e., the correlation between microwave observations and soil moisture is only indirect and comes from the statistical correlation between vegetation and soil moisture). Second, this analysis enables an objective comparison of the relative potential of the various satellite observations for soil moisture retrieval when other conditions are held constant. The second part of this study benefits from this synthesis to derive a relationship between satellite observations and soil moisture at a global scale. C1 CNRS, LERMA, Observ Paris, F-75014 Paris, France. Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Ecole Polytech, CNRS, Inst Pierre Simon Laplace, Meteorol Dynam Lab, F-91128 Palaiseau, France. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. RP CNRS, LERMA, Observ Paris, 61 Ave Observ, F-75014 Paris, France. EM catherine.prigent@obspm.fr; faires@giss.nasa.gov; wrossow@giss.nasa.gov; robock@envsci.rutgers.edu RI Rossow, William/F-3138-2015; Robock, Alan/B-6385-2016 NR 65 TC 54 Z9 57 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 13 PY 2005 VL 110 IS D7 AR D07110 DI 10.1029/2004JD005087 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 917QU UT WOS:000228480400002 ER PT J AU Yuan, DL AF Yuan, DL TI Role of the Kelvin and Rossby waves in the seasonal cycle of the equatorial Pacific Ocean circulation SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-SURFACE TEMPERATURE; TROPICAL PACIFIC; WESTERN BOUNDARIES; MODEL SIMULATION; HEAT-BALANCE; WIND STRESS; EL-NINO; REFLECTION; VARIABILITY; ATMOSPHERE AB The dynamics of the seasonal cycle of the equatorial Pacific Ocean circulation are investigated in a hindcast study generated by the Poseidon quasi-isopycnal general ocean circulation model forced by wind stress from a Special Sensor Microwave Imager product and heat flux from an atmospheric mixed layer model. The simulated annual and semiannual oscillations are validated by the Tropical Atmosphere-Ocean mooring measurements and the altimetry sea levels on the equator, based on which the roles of the equatorial Kelvin and Rossby waves in the seasonal cycle dynamics are investigated. The Kelvin and Rossby waves are extracted from the hindcast in such a way as to treat the model zonal nonlinear momentum terms and wind stress as forcing terms so that the validity of the linear theory on wave propagation and reflection can be examined. It is found that the reflections of the first baroclinic mode waves at the Pacific western and eastern boundaries are in good agreement with the linear theory. In comparison, the reflections of the second and higher baroclinic mode waves are significantly different from the linear theory, suggesting that the reflections are potentially nonlinear. The hindcast has simulated the westward propagation of the dominant annual oscillations of the seasonal sea level in the central basin and the eastward propagation of the dominant semi-annual oscillations of the seasonal sea level in the western and eastern basins successfully. The westward propagation of the annual oscillations is primarily associated with the annual Rossby waves forced by the annual winds in the eastern-to-central equatorial Pacific, the upwelling phase of which forces progressive springtime reversal of the surface zonal currents from the east to the west. However, the internal dynamics of the ocean alter the amplitudes and phases of the springtime reversal significantly. The results of this study have shown that the internal dynamics of the ocean are an important source of the semiannual oscillations in the equatorial Pacific Ocean. The semi-annual harmonics of the Rossby waves are boosted by the internal dynamics and eventually dominate the seasonal cycle in the far western Pacific. The reflections of the Rossby waves at the western boundary produce semi-annual dominant Kelvin waves, which force significant semi-annual oscillations of sea level in the eastern basin. C1 State Ocean Adm, Inst Oceanog 1, Qingdao, Peoples R China. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. RP Yuan, DL (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci Data & Informat Serv Ctr, Greenbelt, MD 20771 USA. EM dyuan@daac.gsfc.nasa.gov NR 53 TC 10 Z9 10 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 13 PY 2005 VL 110 IS C4 AR C04004 DI 10.1029/2004JC002344 PG 14 WC Oceanography SC Oceanography GA 917QY UT WOS:000228481000001 ER PT J AU Leventis, N Dass, A AF Leventis, N Dass, A TI Demonstration of the elusive concentration-gradient paramagnetic force SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MAGNETIC-FIELD; ELECTRODES; TRANSPORT; GOLD; MAGNETOELECTROCHEMISTRY; DIFFUSION; MOLECULES; SYSTEMS C1 NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. Univ Missouri, Dept Chem, Rolla, MO 65409 USA. RP Leventis, N (reprint author), NASA, Glenn Res Ctr, Div Mat, 21000 Brookpk Rd,MS 49-1, Cleveland, OH 44135 USA. EM Nicholas.Leventis@nasa.gov RI Dass, Amala/H-4729-2012; Dass, Amal/A-2520-2011 OI Dass, Amala/0000-0001-6942-5451; NR 23 TC 28 Z9 28 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 13 PY 2005 VL 127 IS 14 BP 4988 EP 4989 DI 10.1021/ja043169b PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 914LQ UT WOS:000228229600002 PM 15810811 ER PT J AU Bandara, SV Gunapala, SD Liu, JK Rafol, SB Hill, CJ Ting, DZY Mumolo, JM Trinh, TQ Fastenau, JM Liu, AWK AF Bandara, SV Gunapala, SD Liu, JK Rafol, SB Hill, CJ Ting, DZY Mumolo, JM Trinh, TQ Fastenau, JM Liu, AWK TI Tuning and tailoring of broadband quantum-well infrared photodetector responsivity spectrum SO APPLIED PHYSICS LETTERS LA English DT Article ID FOCAL-PLANE ARRAY AB The spectral response of quantum-well infrared photodetectors (QWIPs) based on the III-V material system are tailorable to narrow or broad bandwidths within mid- and long-wavelength infrared bands. Typical broad-band QWIPs show considerable spectral shape change with bias voltage, particularly near the cut-off wavelength region. Two alternatives to the typical broadband QWIP design have been demonstrated. These designs consist of two multiquantum-well QW) stacks or alternatively placed QWs and produce nearly fixed spectrums within the operating bias voltages. Flexibility in many design parameters of these detectors allows for tuning and tailoring the spectral shape according to application requirements, specifically for spectral imaging instruments. (C) 2005 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. IQE Inc, Bethlehem, PA 18015 USA. RP Bandara, SV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 18 Z9 18 U1 1 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 11 PY 2005 VL 86 IS 15 AR 151104 DI 10.1063/1.1900313 PG 3 WC Physics, Applied SC Physics GA 923HS UT WOS:000228901600004 ER PT J AU Yaqoob, T Serlemitsos, P AF Yaqoob, T Serlemitsos, P TI Iron K features in the quasar E1821+643: Evidence for gravitationally redshifted absorption? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; quasars : absorption lines; quasars : emission lines; quasars : individual (E1821+643); X-rays : galaxies ID VELOCITY IONIZED OUTFLOW; EMISSION-LINE; GRATING SPECTROSCOPY; BLACK-HOLE; H1821+643; GALAXIES; SPECTROMETER; CLUSTER; DISK; GAS AB We report a Chandra High-Energy Grating (HEG) detection of a narrow, redshifted absorption line superposed on the red wing of a broad Fe K line in the z = 0.297 quasar E1821+ 643. The absorption line is detected at a confidence level, estimated by two different methods, in the range similar to 2 - 3 sigma. Although the detection significance is not high enough to exclude a nonastrophysical origin, accounting for the absorption feature when modeling the X-ray spectrum implies that the Fe K emission line is broad and consistent with an origin in a relativistic accretion disk. Ignoring the apparent absorption feature leads to the conclusion that the Fe K emission line is narrower and also affects the inferred peak energy of the line ( and hence the inferred ionization state of Fe). If the absorption line ( at similar to 6.2 keV in the quasar frame) is real, then we argue that it could be due to gravitationally redshifted Fe xxv or Fe xxvi resonance absorption within similar to 10 - 20 gravitational radii of the putative central black hole. The absorption line is not detected in earlier ASCA and Chandra Low-Energy Grating ( LEG) observations, but the absorption line is not unequivocally ruled out by these data. The Chandra HEG Fe K emission line is consistent with an origin predominantly in Fe I - XVII or so. In an ASCA observation 8 years earlier, the Fe K line peaked at similar to 6.6 keV, closer to the energies of He-like Fe triplet lines. Furthermore, in a Chandra LEG grating observation, the Fe K line profile was double peaked, one peak corresponding to Fe I - XVII or so and the other peak to Fe xxvi Ly alpha. Such a wide range in ionization states of Fe is not ruled out by the HEG and ASCA data either and is suggestive of a complex structure for the line emitter. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yaqoob, T (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NR 21 TC 25 Z9 25 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 112 EP 122 DI 10.1086/428432 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700011 ER PT J AU Smith, RK Edgar, RJ Plucinsky, PP Wargelin, BJ Freeman, PE Biller, BA AF Smith, RK Edgar, RJ Plucinsky, PP Wargelin, BJ Freeman, PE Biller, BA TI Chandra observations of MBM 12 and models of the local bubble SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : bubbles; plasmas; supernova remnants; X-rays : ISM ID RAY BACKGROUND FLUX; INTERSTELLAR-MEDIUM; SOLAR-WIND; CHARGE-TRANSFER; HOT GAS; O VI; EMISSION; LINE; RECOMBINATION; SPECTRA AB Chandra observations toward the nearby molecular cloud MBM 12 show unexpectedly strong and nearly equal foreground O VIII and O VII emission. As the observed portion of MBM 12 is optically thick at these energies, the emission lines must be formed nearby, coming from either the Local Bubble (LB) or charge exchange with ions from the Sun. Equilibrium models for the LB predict stronger O VII than O VIII, so these results suggest that the LB is far from equilibrium or that a substantial portion of OVIII is from another source, such as charge exchange within the solar system. Despite the likely contamination, we can combine our results with other EUV and X-ray observations to reject LB models that posit a cool recombining plasma as the source of LB X-rays. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Carnegie Mellon Univ, Dept Stat, Pittsburgh, PA 15213 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Smith, RK (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM rsmith@milkyway.gsfc.nasa NR 66 TC 37 Z9 37 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 225 EP 234 DI 10.1086/428568 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700021 ER PT J AU Kovacevic, E Stefanovic, I Berndt, J Pendleton, YJ Winter, J AF Kovacevic, E Stefanovic, I Berndt, J Pendleton, YJ Winter, J TI A candidate analog for carbonaceous interstellar dust: Formation by reactive plasma polymerization SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; infrared : ISM; ISM : lines and bands; line : identification; methods : laboratory ID ULTRALUMINOUS INFRARED GALAXIES; HYDROGENATED AMORPHOUS-CARBON; 3.4-MU-M ABSORPTION FEATURE; ACTIVE GALACTIC NUCLEUS; LINE-OF-SIGHT; MICRON SPECTROSCOPY; HYDROCARBON DUST; BAND; ICE; CONSTRAINTS AB Carbonaceous compounds are a significant component of interstellar dust, and the composition and structure of such materials is therefore of key importance. We present 1.5 - 15 mu m spectra of a plasma-polymerized carbonaceous material produced in radio-frequency discharge under low pressure, using C(2)H(2) as a precursor component. The infrared spectra of the resulting spheroidal carbonaceous nanoparticles reveal a strong aliphatic band (3.4 mu m feature), weak OH and carbonyl bands, and traces of aromatic compounds, all characteristics identified with dust in the diffuse interstellar medium of our Galaxy. The plasma polymerization process described here provides a convenient way to make carbonaceous interstellar dust analogs under controlled conditions and to compare their characteristics with astronomical observations. Here we focus on a comparison with the IR spectra of interstellar dust. The IR spectrum of carbonaceous dust in the diffuse interstellar medium is characterized by a strong 3.4 mu m C - H stretching band and weak 6.8 and 7.2 mu m C-H bending bands, with little evidence for the presence of oxygen in the form of carbonyl (C=O) or hydroxide ( OH) groups. The plasma polymerization products produced under oxygen-poor conditions compare well with the peak position and profiles of the observed IR spectrum of diffuse dust. In addition, we find that addition of nitrogen to the plasma results in bands at 6.15 mu m (C=N band) and at 3 mu m (NH band). We note that, with the addition of nitrogen, the 3.4 mu m hydrocarbon band diminishes greatly in strength as the NH band grows. This may have implications for the puzzling absence of the 3.4 mu m hydrocarbon bands in the IR spectra of dust in dense molecular clouds, given that the presence of nitrogen-related bands has been established in dense-cloud dust. C1 Ruhr Univ Bochum, Inst Expt Phys 2, D-44780 Bochum, Germany. Inst Phys, YU-11001 Belgrade, Serbia Monteneg, Serbia Monteneg. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. RP Kovacevic, E (reprint author), Ruhr Univ Bochum, Inst Expt Phys 2, D-44780 Bochum, Germany. EM ek@ep2.rub.de RI Kovacevic, Eva/B-6762-2008; Stefanovic, Ilija/F-5444-2010 OI Stefanovic, Ilija/0000-0002-1652-1287 NR 77 TC 47 Z9 47 U1 0 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 242 EP 251 DI 10.1086/428392 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700023 ER PT J AU Hamaguchi, K Corcoran, MF Petre, R White, NE Stelzer, B Nedachi, K Kobayashi, N Tokunaga, AT AF Hamaguchi, K Corcoran, MF Petre, R White, NE Stelzer, B Nedachi, K Kobayashi, N Tokunaga, AT TI Discovery of extremely embedded X-ray sources in the R Coronae Australis star-forming core SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : activity; stars : magnetic fields; stars : pre-main-sequence; stars : rotation; X-rays : stars ID MAIN-SEQUENCE STARS; HIGH-RESOLUTION; XMM-NEWTON; CHANDRA OBSERVATION; MOLECULAR CLOUDS; RADIO-EMISSION; T-TAURI; PROTOSTAR; FLARES; PERFORMANCE AB With the XMM-Newton and Chandra observatories, we detected two extremely embedded X-ray sources in the R Corona Australis (R CrA) star-forming core, near IRS 7. These sources, designated as X-E and X-W, have X-ray absorption columns of similar to 3 x 10(23) cm(-2) equivalent to A(V) similar to 180 mag. They are associated with the VLA centimeter radio sources 10E and 10W, respectively; XW is the counterpart of the near-infrared source IRS 7, whereas XE has no K-band counterpart above 19.4 mag. This indicates that XE is younger than typical Class I protostars, probably a Class 0 protostar, or in an intermediate phase between Class 0 and Class I. The X-ray luminosity of X-E varied between 29 < log L-X < 31.2 ergs s(-1) on timescales of 3 - 30 months; X-E also showed a monotonic increase in X-ray brightness by a factor of 2 in 30 ks during an XMM-Newton observation. The XMM-Newton spectra indicate emission from a hot plasma with kT similar to 3-4 keV and also show fluorescent emission from cold iron. Although the X-ray spectrum from X-E is similar to flare spectra from Class I protostars in luminosity and temperature, the light curve does not resemble the light curves of magnetically generated X-ray flares, because the variability timescale of X-E is too long and variations in X-ray count rate were not accompanied by variations in spectral hardness. The short-term variation of X-E may be caused by the partial blocking of the X-ray plasma, while the month-long flux enhancement may be driven by mass accretion. C1 NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. INAF, Osservatorio Astron Palermo, I-90134 Palermo, Italy. Univ Tokyo, Inst Astron, Tokyo 1810015, Japan. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. CNR, Washington, DC 20001 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. RP Hamaguchi, K (reprint author), NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. EM kenji@milkyway.gsfc.nasa.gov; corcoran@lheapop.gsfc.nasa.gov; robert.petre-1@nasa.gov; nwhite@lheapop.gsfc.nasa.gov; stelzer@astropa.unipa.it; nedachi@subaru.naoj.org; naoto@ioa.s.u-tokyo.ac.jp; tokunaga@ifa.hawaii.edu RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 47 TC 42 Z9 42 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 291 EP 301 DI 10.1086/428434 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700027 ER PT J AU Titarchuk, L Shrader, C AF Titarchuk, L Shrader, C TI Downscattering due to wind outflows in compact X-ray sources: Theory and interpretation SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; radiation mechanisms : nonthermal; stars : individual (Cygnus X-1, Cygnus X-3, GS 1353-64, GX 339-4) ID MONTE-CARLO SIMULATIONS; CONVERGING FLUID-FLOW; TRANSMISSION GRATING SPECTROMETER; 1ST INTEGRAL OBSERVATIONS; BLACK-HOLE; COMPTON-SCATTERING; REFLECTION; ACCRETION; RADIATION; BINARIES AB A number of recent lines of evidence point toward the presence of hot, outflowing plasma from the central regions of compact Galactic and extragalactic X-ray sources. In addition, it has long been noted that many of these sources exhibit an "excess'' continuum component above similar to 10 keV, usually attributed to Compton reflection from a static medium. Motivated by these facts, as well as by recent observational constraints on the Compton reflection models, specifically apparently discrepant variability timescales for line and continuum components in some cases, we consider possible effects of outflowing plasma on the high-energy continuum spectra of accretion-powered compact objects. We present a general formulation for photon downscattering diffusion that includes recoil and Comptonization effects due to divergence of the flow. We then develop an analytical theory for the spectral formation in such systems that allows us to derive formulae for the emergent spectrum. Finally, we perform the analytical model fitting on several Galactic X-ray binaries. Objects that have been modeled with high - covering-fraction Compton reflectors, such as GS 1353 - 64, are included in our analysis. In addition, Cyg X-3, which is widely believed to be characterized by dense circumstellar winds with temperature of the order of 106 K, provides an interesting test case. Data from INTEGRAL and RXTE covering the similar to 3 - 300 keV range are used in our analysis. We further consider the possibility that the widely noted distortion of the power-law continuum above 10 keV may in some cases be explained by these spectral softening effects. C1 George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. USN, Res Lab, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Lanham, MD 20706 USA. RP Titarchuk, L (reprint author), George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. EM ltitarchuk@ssd5.nrl.navy.mil; Chris.R.Shrader@gsfc.nasa.gov NR 34 TC 12 Z9 12 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 362 EP 371 DI 10.1086/424918 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700033 ER PT J AU Chen, CH Jura, M Gordon, KD Blaylock, M AF Chen, CH Jura, M Gordon, KD Blaylock, M TI A Spitzer study of dusty disks in the Scorpius-Centaurus OB association SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; open clusters and associations : individual (Sco-Cen Association); planetary systems : formation ID T-TAURI STARS; CIRCUMSTELLAR DISKS; HR 4796A; SYSTEM; PARTICLES; FORCES; AGE AB We have obtained Spitzer Space Telescope MIPS observations of 40 F- and G-type common proper motion members of the Scorpius-Centaurus OB association with ages between 5 and 20 Myr at 24 and 70 mu m. We report the detection of 14 objects that possess 24 mu m fluxes >= 30% larger than their predicted photospheres, tentatively corresponding to a disk fraction of >= 35%, including seven objects that also possess 70 mu m excesses >= 100 times larger than their predicted photospheres. The 24 mu m plus 70 mu m excess sources possess high fractional infrared luminosities, L-IR/L-* = 7 x 10(-4) to 3 x 10(-3); either they possess optically thin, dusty beta Pictoris - like disks or compact, opaque HD 98800 - like disks. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Chen, CH (reprint author), CALTECH, Jet Prop Lab, M-S 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM christine.chen@jpl.nasa.gov; jura@astro.ucla.edu NR 36 TC 82 Z9 82 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 493 EP 501 DI 10.1086/428607 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700045 ER PT J AU Ko, YK Raymond, JC Gibson, SE Alexander, D Strachan, L Holzer, T Gilbert, H St Cyr, OC Thompson, BJ Pike, CD Mason, HE Burkepile, J Thompson, W Fletcher, L AF Ko, YK Raymond, JC Gibson, SE Alexander, D Strachan, L Holzer, T Gilbert, H St Cyr, OC Thompson, BJ Pike, CD Mason, HE Burkepile, J Thompson, W Fletcher, L TI Multialtitude observations of a coronal jet during the third Whole Sun Month Campaign SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : coronal mass ejections (CMEs) ID X-RAY JETS; EXTREME-ULTRAVIOLET JETS; H-ALPHA SURGES; MASS EJECTIONS; SOLAR MINIMUM; MAGNETIC RECONNECTION; OUTFLOW VELOCITIES; ATOMIC DATABASE; EMISSION-LINES; ACTIVE-REGION AB On 1999 August 26, a coronal jet occurred at the northwest limb near a sigmoid active region (AR 8668) that was the target for a joint observation plan ( SOHO joint observing program 106) during the third Whole Sun Month Campaign. This jet was observed by several instruments at the limb (SOHO/CDS, SOHO/EIT, TRACE, and Mauna Loa Solar Observatory CHIP and PICS) and at 1.64 R-. (SOHO/UVCS). At the limb, this jet event displayed both low- and high-temperature components. Both high- and low- temperature components were evident during the early phase ( first 20 minutes) of the event. However, the low- temperature component is maintained for similar to 1 hr after the higher temperature component is gone. There is a second brightening ( a possible second jet) seen by EIT and TRACE about 50 minutes after the onset of the first jet. The line-of-sight motion at the limb began with a 300 km s(-1) redshift and evolved to a 200 km s(-1) blueshift. At 1.64 R-., the intensities of Ly alpha and Ly beta in the jet increased by a factor of several hundred compared with the background corona. The C III lambda 977 line also brightened significantly. This indicates low- temperature [similar to(1-2) x 10(5) K] emission in the jet, while the intensities of O VI lambda 1032 and O VI lambda 1037 increased by as much as a factor of 8. The UVCS data show evidence of heating at the early phase of the event. The Doppler shift in the lines indicates that the line-of-sight (LOS) velocity in the jet started from similar to 150 km s(-1) in blueshift and ended at similar to 100 km s(-1) in redshift. This LOS motion seen at 1.64 R-. was apparently opposite to what was observed when the jet emerged from the limb. The Doppler dimming analysis indicates that the radial outflow speed correlates with the magnitude of the LOS speed. Interestingly, UVCS observations at 2.33 and 2.66 R-. show no trace of the jet and SOHO/LASCO observations also yield no firm detection. We find that a simple ballistic model can explain most of the dynamical properties of this jet, while the morphology and the thermal properties agree well with reconnection-driven X-ray jet models. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rutherford Appleton Lab, Dept Space Sci, Didcot OX11 0QX, Oxon, England. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 0WA, England. GSI, Largo, MD 20774 USA. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. RP Ko, YK (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Gibson, Sarah/A-9189-2011; Gilbert, Holly/C-7215-2012; Thompson, William/D-7376-2012; Thompson, Barbara/C-9429-2012 NR 42 TC 22 Z9 22 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 519 EP 539 DI 10.1086/428479 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700048 ER PT J AU Liu, XM Shemansky, DE Ciocca, M Kanik, I Ajello, JM AF Liu, XM Shemansky, DE Ciocca, M Kanik, I Ajello, JM TI Analysis of the physical properties of the N-2 c ' (1)Sigma(+)(u)(0)-X (1)Sigma(+)(g)(0) transition SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : molecules; methods : laboratory; molecular data; planets and satellites : general; ultraviolet : general ID ELECTRON-IMPACT EXCITATION; ULTRAVIOLET EMISSION-SPECTRUM; VUV ABSORPTION-SPECTRUM; HIGH-RESOLUTION; MOLECULAR NITROGEN; RYDBERG STATES; C'(4) (1)SIGMA(U)(+); UPPER-ATMOSPHERE; CROSS-SECTIONS; EUV EMISSION AB A high-resolution, 33 m angstrom (FWHM), optically thin emission study of the N-2 c' (1)Sigma(u)(+) (0) - X-1 Sigma(g)(+) (0) band transition has been performed with electron impact at 100 eV. Recently measured line oscillator strengths and lifetimes have been examined by comparing model spectra with the observed emission. Good agreement between model and data indicates consistency between the measured lifetimes and oscillator strengths. Predissociation yields for various J(j) levels are estimated. The calculated predissociation yield is in the range 0.2 - 0.5 for J(j) = 4-23 and negligible for J(j) = 0-2. C1 Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA. Eastern Kentucky Univ, Dept Phys & Astron, Richmond, KY 40475 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, XM (reprint author), Univ So Calif, Dept Aerosp & Mech Engn, Olin Hall Engn 430, Los Angeles, CA 90089 USA. EM xianming@usc.edu; dons@hippolyta.usc.edu; marco.ciocca@eku.edu; ikanik@mail1.jpl.nasa.gov; jajello@mail1.jpl.nasa.gov NR 44 TC 13 Z9 14 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP 579 EP 584 DI 10.1086/428641 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AV UT WOS:000228197700053 ER PT J AU Boselli, A Boissier, S Cortese, L de Paz, AG Buat, V Iglesias-Paramo, J Madore, BF Barlow, T Bianchi, L Byun, YI Donas, J Forster, K Friedman, PG Heckman, TM Jelinsky, P Lee, YW Malina, R Martin, DC Milliard, B Morrissey, P Neff, S Rich, RM Schiminovich, D Seibert, M Siegmund, O Small, T Szalay, AS Welsh, B Wyder, TK AF Boselli, A Boissier, S Cortese, L de Paz, AG Buat, V Iglesias-Paramo, J Madore, BF Barlow, T Bianchi, L Byun, YI Donas, J Forster, K Friedman, PG Heckman, TM Jelinsky, P Lee, YW Malina, R Martin, DC Milliard, B Morrissey, P Neff, S Rich, RM Schiminovich, D Seibert, M Siegmund, O Small, T Szalay, AS Welsh, B Wyder, TK TI GALEX ultraviolet observations of the interacting galaxy NGC 4438 in the Virgo Cluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (Virgo); galaxies : individual (NGC 4435, NGC 4438); galaxies : interactions; ultraviolet : galaxies ID STAR-FORMATION; SURFACE PHOTOMETRY; EVOLUTION-EXPLORER; DISC GALAXIES; TIDAL TAILS; GAS; EMISSION; HISTORY; ATLAS AB We present GALEX near-ultraviolet (2310 angstrom) and far-ultraviolet (1530 angstrom) images of the interacting galaxy NGC 4438 (Arp 120) in the center of the Virgo Cluster. These images show an extended ( 20 kpc) tidal tail at the northwest edge of the galaxy that was previously undetected at other wavelengths; this tail is 15 - 25 kpc from NGC 4438' s nucleus. Except for in the nucleus, the UV morphology of NGC 4438 is totally different from the H alpha + [N II] morphology, which is more similar to the X-ray emission, confirming its gas cooling origin. We study the star formation history of NGC 4438 by combining spectrophotometric data in the UV-visible-near-IR wavelength range with population synthesis and galaxy evolution models. The data are consistent with a recent (similar to 10 Myr), instantaneous burst of star formation in the newly discovered UV northwestern tail that is significantly younger than the age of the tidal interaction with NGC 4435, dated by dynamical models at similar to 100 Myr ago. Recent star formation events are also present at the edge of the northern arm and in the southern tail, while totally lacking in the other regions, which are dominated by the old stellar population that was perturbed during the dynamical interaction with NGC 4435. The contribution of this recent starburst to the total galaxy stellar mass is lower than 0.1%, an extremely low value for such a violent interaction. High-velocity, off-center tidal encounters such as that observed in Arp 120 are thus not sufficient to significantly increase the star formation activity of cluster galaxies. C1 Lab Astrophys Marseille, F-13376 Marseille, France. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Yonsei Univ, Ctr Space Astrophy, Seoul 120749, South Korea. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Boselli, A (reprint author), Lab Astrophys Marseille, BP 8,Traverse Siphon, F-13376 Marseille, France. RI Gil de Paz, Armando/J-2874-2016; OI Gil de Paz, Armando/0000-0001-6150-2854; malina, roger/0000-0003-3399-3865; Cortese, Luca/0000-0002-7422-9823; Iglesias-Paramo, Jorge/0000-0003-2726-6370 NR 34 TC 39 Z9 39 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP L13 EP L16 DI 10.1086/429377 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AX UT WOS:000228197900004 ER PT J AU Cortese, L Boselli, A Gavazzi, G Paramo, JI Madore, BF Barlow, T Bianchi, L Byun, YI Donas, J Forster, K Friedman, PG Heckman, TM Jelinsky, P Lee, YW Malina, R Martin, DC Milliard, B Morrissey, P Neff, S Rich, RM Schiminovich, D Siegmund, O Small, T Szalay, AS Treyer, MA Welsh, B Wyder, TK AF Cortese, L Boselli, A Gavazzi, G Paramo, JI Madore, BF Barlow, T Bianchi, L Byun, YI Donas, J Forster, K Friedman, PG Heckman, TM Jelinsky, P Lee, YW Malina, R Martin, DC Milliard, B Morrissey, P Neff, S Rich, RM Schiminovich, D Siegmund, O Small, T Szalay, AS Treyer, MA Welsh, B Wyder, TK TI The GALEX ultraviolet luminosity function of the cluster of galaxies A1367 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (A1367); galaxies : evolution; galaxies : luminosity function, mass function; ultraviolet : galaxies ID REDSHIFT SURVEY; STAR-FORMATION; NEARBY CLUSTERS; VIRGO CLUSTER; SURFACE PHOTOMETRY; EVOLUTION-EXPLORER; COMA CLUSTER; ABELL-1367; TELESCOPE; RADIATION AB We present the Galaxy Evolution Exlorer (GALEX) near-ultraviolet (2310 angstrom) and far-ultraviolet ( 1530 angstrom) galaxy luminosity functions of the nearby cluster of galaxies A1367 in the magnitude range -20.3 <= M-AB <= -13.3. The luminosity functions are consistent with previous (similar to 2 mag shallower) estimates based on the FOCA and FAUST experiments, but they display a steeper faint-end slope than the GALEX luminosity function for local field galaxies. Using spectrophotometric optical data, we select star-forming systems from quiescent galaxies and study their separate contributions to the cluster luminosity function. We find that the UV luminosity function of cluster star-forming galaxies is consistent with the field. The difference between the cluster and field luminosity functions is entirely due to the contribution at low luminosities (M-AB > -16 mag) of non - star-forming, early-type galaxies that are significantly overdense in clusters. C1 Lab Astrophys Marseille, F-13376 Marseille, France. Univ Studi Milano Bicocca, I-20126 Milan, Italy. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Yonsei Univ, Ctr Space Astrophys, Seoul 120749, South Korea. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Cortese, L (reprint author), Lab Astrophys Marseille, BP 8,Traverse Siphon, F-13376 Marseille, France. OI malina, roger/0000-0003-3399-3865; Cortese, Luca/0000-0002-7422-9823 NR 36 TC 15 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 2005 VL 623 IS 1 BP L17 EP L20 DI 10.1086/429993 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914AX UT WOS:000228197900005 ER PT J AU Chu, DA Remer, LA Kaufman, YJ Schmid, B Redemann, J Knobelspiesse, K Chern, JD Livingston, J Russell, PB Xiong, X Ridgway, W AF Chu, DA Remer, LA Kaufman, YJ Schmid, B Redemann, J Knobelspiesse, K Chern, JD Livingston, J Russell, PB Xiong, X Ridgway, W TI Evaluation of aerosol properties over ocean from Moderate Resolution Imaging Spectroradiometer (MODIS) during ACE-Asia SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SKY RADIANCE MEASUREMENTS; OPTICAL-PROPERTIES; SAHARAN DUST; MINERAL DUST; TROPOSPHERIC AEROSOLS; AIRBORNE SIMULATOR; AIR-POLLUTION; EAST-ASIA; SUN; LAND AB The Aerosol Characterization Experiment-Asia (ACE-Asia) was conducted in March-May 2001 in the western North Pacific in order to characterize the complex mix of dust, smoke, urban/industrial pollution, and background marine aerosol that is observed in that region in springtime. The Moderate Resolution Imaging Spectroradiometer (MODIS) provides a large-scale regional view of the aerosol during the ACE-Asia time period. Focusing only on aerosol retrievals over ocean, MODIS data show latitudinal and longitudinal variation in the aerosol characteristics. Typically, aerosol optical depth (tau(alpha)) values at 0.55 mu m are highest in the 30 degrees-50 degrees latitude band associated with dust outbreaks. Monthly mean tau(alpha) in this band ranges similar to 0.40-70, although large differences between monthly mean and median values indicate the periodic nature of these dust outbreaks. The size parameters, fine mode fraction (eta), and effective radius (r(eff)) vary between monthly mean values of eta = 0.47 and r(eff) = 0.75 mu m in the cleanest regions far offshore to approximately eta = 0.85 and r(eff) = 0.30 mu m in near-shore regions dominated by biomass burning smoke. The collocated MODIS retrievals with airborne, ship-based, and ground-based radiometers measurements suggest that MODIS retrievals of spectral optical depth fall well within expected error (Delta tau(alpha) = +/- 0.03 +/- 0.05 tau(alpha)) except in situations dominated by dust, in which cases MODIS overestimate both the aerosol loading and the aerosol spectral dependence. Such behavior is consistent with issues related to particle nonsphericity. Comparisons of MODIS-derived r(eff) with AERONET retrievals at the few occurrences of collocations show MODIS systematically underestimates particle size by 0.2 mu m. Multiple-year analysis of MODIS aerosol size parameters suggests systematic differences between the year 2001 and the years 2000 and 2002, which are traced to instrumental electronic cross talk. Sensitivity studies show that such calibration errors are negligible in tau(alpha) retrievals but are more pronounced in size parameter retrievals, especially for dust and sea salt. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Sci Syst & Applicat Inc, Lanham, MD USA. NASA, Goddard Space Flight Ctr, Hydrol Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Chu, DA (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. EM achu@climate.gsfc.nasa.gov; lorraine.a.remer@nasa.gov; yoram.j.kaufman@nasa.gov; bschmid@mail.arc.nasa.gov; jredemann@mail.arc.nasa.gov; kirk@simbios.gsfc.nasa.gov; jchern@agnes.gsfc.nasa.gov; jlivingston@mail.arc.nasa.gov; philip.b.russell@nasa.gov; xiaoxiong.xiong_1@nasa.gov; ridgway@climate.gsfc.nasa.gov RI Knobelspiesse, Kirk/S-5902-2016 OI Knobelspiesse, Kirk/0000-0001-5986-1751 NR 48 TC 76 Z9 77 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 9 PY 2005 VL 110 IS D7 AR D07308 DI 10.1029/2004JD005208 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916IN UT WOS:000228378700003 ER PT J AU Wing, S Johnson, JR Jen, J Meng, CI Sibeck, DG Bechtold, K Freeman, J Costello, K Balikhin, M Takahashi, K AF Wing, S Johnson, JR Jen, J Meng, CI Sibeck, DG Bechtold, K Freeman, J Costello, K Balikhin, M Takahashi, K TI Kp forecast models SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND DATA; GEOMAGNETIC-ACTIVITY; NEURAL-NETWORKS; FIELD; MAGNETOSPHERE; PREDICTIONS; BOUNDARY; PRECIPITATION; INTENSITY; SHEET AB Magnetically active times, e.g., Kp > 5, are notoriously difficult to predict, precisely the times when such predictions are crucial to the space weather users. Taking advantage of the routinely available solar wind measurements at Langrangian point (L1) and nowcast Kps, Kp forecast models based on neural networks were developed with the focus on improving the forecast for active times. To satisfy different needs and operational constraints, three models were developed: (1) a model that inputs nowcast Kp and solar wind parameters and predicts Kp 1 hour ahead; (2) a model with the same input as model 1 and predicts Kp 4 hour ahead; and (3) a model that inputs only solar wind parameters and predicts Kp 1 hour ahead (the exact prediction lead time depends on the solar wind speed and the location of the solar wind monitor). Extensive evaluations of these models and other major operational Kp forecast models show that while the new models can predict Kps more accurately for all activities, the most dramatic improvements occur for moderate and active times. Information dynamics analysis of Kp suggests that geospace is more dominated by internal dynamics near solar minimum than near solar maximum, when it is more directly driven by external inputs, namely solar wind and interplanetary magnetic field ( IMF). C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Sheffield, Dept Automat Control & Syst Engn, Sheffield S1 3JD, S Yorkshire, England. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Wing, S (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. EM simon.wing@jhuapl.edu RI Sibeck, David/D-4424-2012 NR 39 TC 49 Z9 51 U1 3 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 9 PY 2005 VL 110 IS A4 AR A04203 DI 10.1029/2004JA010500 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 916JS UT WOS:000228381800002 ER PT J AU Doran, PT Priscu, JC Lyons, WB Walsh, JE Fountain, AG McKnight, DM Moorhead, DL Virginia, RA Wall, DH Clow, GD Fritsen, CH McKay, CP Parsons, AN AF Doran, PT Priscu, JC Lyons, WB Walsh, JE Fountain, AG McKnight, DM Moorhead, DL Virginia, RA Wall, DH Clow, GD Fritsen, CH McKay, CP Parsons, AN TI Comment on "El Nino suppresses Antarctic warming" by N. Bertler et al. SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material ID HEMISPHERE CLIMATE-CHANGE; MCMURDO DRY VALLEYS; LAKE-LEVEL; SIMULATION C1 Univ Illinois, Dept Earth & Environm Sci, Chicago, IL 60607 USA. Denver Fed Ctr, US Geol Survey, Climate Program, Denver, CO 80225 USA. Portland State Univ, Dept Geol, Portland, OR 97207 USA. Univ Nevada, Desert Res Inst, Div Earth & Ecosyst Sci, Reno, NV 89512 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Nasa, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94305 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Toledo, Dept Earth Ecol & Environm Sci, Toledo, OH 43606 USA. NERC, Swindon SN2 1EU, Wilts, England. Montana State Univ, Bozeman, MT 59717 USA. Dartmouth Coll, Environm Studies Program, Hanover, NH 03755 USA. Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. Univ Alaska Fairbanks, Ctr Global Change & Arctic Syst Res, Fairbanks, AK 99775 USA. RP Doran, PT (reprint author), Univ Illinois, Dept Earth & Environm Sci, 845 W Taylor St, Chicago, IL 60607 USA. EM pdoran@uic.edu RI Wall, Diana/F-5491-2011; OI MCKNIGHT, DIANE/0000-0002-4171-1533 NR 8 TC 0 Z9 0 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 8 PY 2005 VL 32 IS 7 AR L07706 DI 10.1029/2004GL021716 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 916HW UT WOS:000228377000001 ER PT J AU Bills, BG Comstock, RL AF Bills, BG Comstock, RL TI Forced obliquity variations of Mercury SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GENERALIZED CASSINIS LAWS; SOLAR-SYSTEM; HANSEN COEFFICIENTS; INTERIOR STRUCTURE; CHAOTIC OBLIQUITY; PLANET MERCURY; GRAVITY-FIELD; ROTATION; CORE; MARS AB The spin pole of Mercury is very nearly, but not quite, aligned with its orbit pole. Tidal dissipation has driven the free obliquity to very small values, and the high rate of spin pole precession allows the forced obliquity variations to remain small despite significant variations in orbital inclination and eccentricity. We present calculations of the obliquity for a 10 million year time span, centered on the present. The obliquity remains small, with typical values of 2-4 minutes of arc. The dominant period of obliquity oscillations is 895 kyr, which is also the main period at which the orbital inclination varies. If the orbit pole precession rate were uniform, dissipation would have driven Mercury into a Cassini state, in which the spin pole and orbit pole remain coplanar with the invariable pole, as the spin pole precesses about the moving orbit pole. However, due to the nonuniform orbit precession rate, this simple coplanar configuration is not maintained, except on a mode-by-mode basis. That is, when the orbit pole motion is represented as a sum of normal modes of the coupled oscillations of the planetary system, the spin pole coprecesses with the orbit pole at each modal frequency. This is a generalization of Cassini's second and third laws of lunar rotation to the case of nonuniform orbit precession. We compare results of a linearized obliquity model with a numerical integration of the equations of motion. The two solutions agree at the level of a few seconds of arc. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bills, BG (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. EM bbills@ucsd.edu RI Bills, Bruce/C-1156-2008 NR 79 TC 5 Z9 5 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 8 PY 2005 VL 110 IS E4 AR E04006 DI 10.1029/2003JE002116 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916JG UT WOS:000228380600001 ER PT J AU Bills, BG Comstock, RL AF Bills, BG Comstock, RL TI Spatial and temporal patterns of solar eclipses by Phobos on Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARTIAN SATELLITES; ORBITAL EVOLUTION; CHAOTIC OBLIQUITY; LASER ALTIMETER; MISSION; CAMERA; ORIGIN; VIKING; MODEL AB The spatial and temporal patterns associated with motion of the shadow of Phobos across the surface of Mars are quite different than those associated with solar eclipses on Earth. We present a simple analysis of variations in the position, velocity, size, and shape of the shadow. Simple expressions give reasonably accurate depictions of the shadow motion, which mainly consists of a subdiurnal longitude cycle and an annual latitude cycle. Over most of each year, there are an average of 3.22 shadow transits per day. The duration of the shadow transit depends on latitude. It is maximum at the equator and is then 11.8% of the orbital synodic period. As the subsolar point moves north, the shadow moves south, and vice versa. There is a narrow band, centered on the equator of Mars, within which every point is eclipsed at least once during each semiannual eclipse season. Outside that band, the density of coverage decreases slowly with increasing distance from the equator, until the limiting latitudes are reached. During epochs, like the present, when the obliquity of Mars is in excess of 21.2 degrees, there are portions of each year during which no eclipses occur. As the obliquity increases beyond that transition value, the durations of the eclipse seasons decrease. The minimum possible eclipse season duration, expressed as a fraction of the Mars year, is the same as the maximum shadow transit duration, expressed as a fraction of the Phobos synodic period, since both ratios depend on the same geometry, which is essentially just the radius of the orbit of Phobos, compared to the radius of Mars. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Bills, BG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM bbills@ucsd.edu RI Bills, Bruce/C-1156-2008 NR 35 TC 7 Z9 7 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 7 PY 2005 VL 110 IS E4 AR E04004 DI 10.1029/2003JE002209 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916JA UT WOS:000228380000001 ER PT J AU Moore, JM Howard, AD AF Moore, JM Howard, AD TI Large alluvial fans on Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID AQUEOUS SEDIMENTATION; WARM; WET; CALIFORNIA; EVOLUTION; DEPOSITS; CLIMATE; SURFACE; REGION; SITE AB Several dozen distinct alluvial fans, 10 to similar to 40 km long downslope, have been observed in highlands craters. Within a search region between 0 degrees and 30 degrees S, alluvial fan-containing craters were found only between 18 degrees and 29 degrees S, and they all occur at around +/- 1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form three distinct clusters. Fans typically descend >1 km from where they disgorge from their alcoves. Longitudinal profiles show that their surfaces are very slightly concave with a mean slope of 2 degrees. Many fans exhibit very long, narrow, low-relief ridges radially oriented downslope, often branching at their distal ends, suggestive of distributaries. Morphometric data for 31 fans were derived from MOLA data and compared with terrestrial fans with high-relief source areas, terrestrial low-gradient alluvial ramps in inactive tectonic settings, and older Martian alluvial ramps along crater floors. The Martian alluvial fans generally fall on the same trends as the terrestrial alluvial fans, whereas the gentler Martian crater floor ramps are similar in gradient to the low-relief terrestrial alluvial surfaces. For a given fan gradient, Martian alluvial fans generally have greater source basin relief than terrestrial fans in active tectonic settings. This suggests that the terrestrial source basins either yield coarser debris or have higher sediment concentrations than their Martian counterpoints. Martian fans (and terrestrial Basin and Range fans) have steeper gradients than the older Martian alluvial ramps (and terrestrial low-relief alluvial surfaces), which is consistent with the construction of Martian fans from dominantly gravel-sized sediment (rather than sand and silt). Martian fans are relatively large and of low gradient, similar to terrestrial fluvial fans rather than debris flow fans (although gravity-scaling uncertainties make the flow regime forming Martian fans uncertain). However, evidence of bedforms accentuated by differential erosion, such as scroll bars, supports the contention that these are fluvially formed fans. Martian fans, at least those in Holden crater, apparently formed around the time of the Noachian-Hesperian boundary. We infer that these fans formed during an episode of enhanced precipitation (probably snow) and runoff, which exhibited both sudden onset and termination. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. RP Moore, JM (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. EM jeff.moore@nasa.gov; ah6p@virginia.edu OI Howard, Alan/0000-0002-5423-1600 NR 61 TC 97 Z9 97 U1 6 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 7 PY 2005 VL 110 IS E4 AR E04005 DI 10.1029/2004JE002352 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916JA UT WOS:000228380000004 ER PT J AU Merka, J Szabo, A Slavin, JA Peredo, M AF Merka, J Szabo, A Slavin, JA Peredo, M TI Three-dimensional position and shape of the bow shock and their variation with upstream Mach numbers and interplanetary magnetic field orientation SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND FLOW; STANDOFF DISTANCE; TERRESTRIAL PLANETS; MODEL PREDICTIONS; UNUSUAL LOCATIONS; MHD SIMULATIONS; MAGNETOSPHERE; MAGNETOSHEATH; MAGNETOPAUSE; IMP-8 AB Peredo et al. (1995) derived a frequently used three-dimensional bow shock model parameterized by the upstream Alfvenic Mach number from the set of approximately 550 bow shock crossings provided by 17 distinct spacecraft over the period of 1963-1980. However, several studies reported some systematic biases in the bow shock model predictions. Therefore we have attempted to improve upon the bow shock model of Peredo et al. (1995) using their original data set and methodology in an effort to better understand these effects. We have performed three-dimensional best fits to the bow shock crossings binned by the upstream Mach numbers M-A, M-S, and M-MS and found that the best fitting surfaces were best ordered with the M-A. In agreement with predictions from the magnetohydrodynamic theory, the results show that the bow shock surface expands when the M-A decreases. The found dawn-dusk asymmetry in the bow wave is consistent with previous studies only in the Geocentric Plasma Ecliptic System (GPE) coordinates but not in the Geocentric Interplanetary Medium (GIPM) coordinates which suggests that the employed data set is not comprehensive enough for resolving this asymmetry. Nor is the Mach cone asymmetry resolved in our data set (not even in the GIPM frame). We have derived two models predicting the statistical position and shape of the bow shock in the GPE or GIPM coordinates. Error analysis shows that the GPE-based model is more accurate and applicable for M-A = 3-20 except the nose region where the model underestimates the bow shock position for M-A < 5. A direct comparison of the model predictions with 5870 IMP 8 bow shock crossings demonstrated high accuracy of predictions and, for the GPE-based model, an exceptional stability of predictions even under extreme upstream conditions. Indeed, the new GPE-based bow shock model is more accurate and equally or more stable than the Formisano (1979), Nemecek and Safrankova (1991), Farris and Russell (1994), Cairns and Lyon (1995), Peredo et al. (1995), or Verigin et al. (2001) models. C1 NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. L3 Commun Govt Serv Inc, Vienna, VA USA. SSAI, Lanham, MD 20706 USA. RP NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Code 612-3, Greenbelt, MD 20771 USA. EM jan.merka@gsfc.nasa.gov; adam.szabo@gsfc.nasa.gov; james.a.slavin@nasa.gov; mauricio_peredo@ssaihq.com RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 46 TC 28 Z9 28 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 7 PY 2005 VL 110 IS A4 AR A04202 DI 10.1029/2004JA010944 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 916JR UT WOS:000228381700002 ER PT J AU Bayes, KD Friedl, RR Sander, SP AF Bayes, KD Friedl, RR Sander, SP TI Kinetics of the reactions of the CHBr2 and CHBr2O2 radicals with O-2 and NO SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ATMOSPHERIC OXIDATION PATHWAYS; ABSORPTION CROSS-SECTIONS; ASSOCIATION REACTIONS; STRATOSPHERIC BROMINE; MOLECULAR-OXYGEN; PEROXY-RADICALS; TOTAL PRESSURE; 760 TORR; BROMOFORM; CHEMISTRY AB When bromoform (CHBr3) is photolyzed at 266 or 303 nm in the presence of O-2 and NO, the formation of secondary Br atoms is observed. By following the rate of growth of this secondary Br atom signal as a function of conditions, rate constants have been determined for the reactions CHBr2 + O-2, CHBr2 + NO (both pressure-dependent), and CHBr2O2 + NO (k(2a) = (1.74 +/- 0. 16) x 10(-11) cm(3) molecule(-1) s(-1) at 23 degrees C). By measuring the amplitude of the secondary Br signal compared to the primary Br formed in the initial photolysis, it is established that the CHBr2O radical spontaneously decomposes to form CHBrO + Br at least 90%, and probably 100%, of the time, in agreement with previous work and with recent ab initio calculations. A survey of four other polybrominated methanes, CH2Br2, CHClBr2, CF2Br2, and CBr4, shows that they all generate secondary Br atoms when photolyzed at 266 nm in the presence Of O-2 and NO, suggesting that their reaction sequences are similar to that of bromoform. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayes, KD (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM kdbayes@jpl.nasa.gov NR 25 TC 7 Z9 7 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD APR 7 PY 2005 VL 109 IS 13 BP 3045 EP 3051 DI 10.1021/jp044842m PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 912WP UT WOS:000228110900008 PM 16833628 ER PT J AU Stapelfeldt, K AF Stapelfeldt, K TI Planetary science - A planet that blinks SO NATURE LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Stapelfeldt, K (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. EM krs@exoplanet.jpl.nasa.gov RI Stapelfeldt, Karl/D-2721-2012 NR 11 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 7 PY 2005 VL 434 IS 7034 BP 707 EP 708 DI 10.1038/434707a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 913NU UT WOS:000228160700021 PM 15815610 ER PT J AU Deming, D Seager, S Richardson, LJ Harrington, J AF Deming, D Seager, S Richardson, LJ Harrington, J TI Infrared radiation from an extrasolar planet SO NATURE LA English DT Article ID TRANSITING PLANET; GIANT PLANETS; MODEL; MIPS AB A class of extrasolar giant planets-the so-called 'hot Jupiters' (ref. 1)-orbit within 0.05 AU of their primary stars ( 1 AU is the Sun-Earth distance). These planets should be hot and so emit detectable infrared radiation(2). The planet HD 209458b (refs 3, 4) is an ideal candidate for the detection and characterization of this infrared light because it is eclipsed by the star. This planet has an anomalously large radius (1.35 times that of Jupiter(5)), which may be the result of ongoing tidal dissipation(6), but this explanation requires a non-zero orbital eccentricity (similar to 0.03; refs 6, 7), maintained by interaction with a hypothetical second planet. Here we report detection of infrared (24-mu m) radiation from HD 209458b, by observing the decrement in flux during secondary eclipse, when the planet passes behind the star. The planet's 24-mu m flux is 55 +/- 10 mu Jy (1 sigma), with a brightness temperature of 1,130 +/- 150 K, confirming the predicted heating by stellar irradiation(2,8). The secondary eclipse occurs at the midpoint between transits of the planet in front of the star (to within +/- 7 min, 1 sigma), which means that a dynamically significant orbital eccentricity is unlikely. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Greenbelt, MD 20771 USA. NASA, Goddard Ctr Astrobiol, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Exoplanet & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Deming, D (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Code 693, Greenbelt, MD 20771 USA. EM Leo.D.Deming@nasa.gov RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 28 TC 397 Z9 400 U1 2 U2 21 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 7 PY 2005 VL 434 IS 7034 BP 740 EP 743 DI 10.1038/nature03507 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 913NU UT WOS:000228160700034 PM 15785769 ER PT J AU Abdou, WA Diner, DJ Martonchik, JV Bruegge, CJ Kahn, RA Gaitley, BJ Crean, KA Remer, LA Holben, B AF Abdou, WA Diner, DJ Martonchik, JV Bruegge, CJ Kahn, RA Gaitley, BJ Crean, KA Remer, LA Holben, B TI Comparison of coincident Multiangle Imaging Spectroradiometer and Moderate Resolution Imaging Spectroradiometer aerosol optical depths over land and ocean scenes containing Aerosol Robotic Network sites SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MISR; RETRIEVAL; MODIS; REFLECTANCE; ALGORITHM; AERONET AB The Multiangle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS), launched on 18 December 1999 aboard the Terra spacecraft, are making global observations of top-of-atmosphere (TOA) radiances. Aerosol optical depths and particle properties are independently retrieved from these radiances using methodologies and algorithms that make use of the instruments' corresponding designs. This paper compares instantaneous optical depths retrieved from simultaneous and collocated radiances measured by the two instruments at locations containing sites within the Aerosol Robotic Network (AERONET). A set of 318 MISR and MODIS images, obtained during the months of March, June, and September 2002 at 62 AERONET sites, were used in this study. The results show that over land, MODIS aerosol optical depths at 470 and 660 nm are larger than those retrieved from MISR by about 35% and 10% on average, respectively, when all land surface types are included in the regression. The differences decrease when coastal and desert areas are excluded. For optical depths retrieved over ocean, MISR is on average about 0.1 and 0.05 higher than MODIS in the 470 and 660 nm bands, respectively. Part of this difference is due to radiometric calibration and is reduced to about 0.01 and 0.03 when recently derived band-to-band adjustments in the MISR radiometry are incorporated. Comparisons with AERONET data show similar patterns. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Abdou, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM a.abdou@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 25 TC 87 Z9 88 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 6 PY 2005 VL 110 IS D10 AR D10S07 DI 10.1029/2004JD004693 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916IQ UT WOS:000228379000001 ER PT J AU Kim, SW Jefferson, A Yoon, SC Dutton, EG Ogren, JA Valero, FPJ Kim, J Holben, BN AF Kim, SW Jefferson, A Yoon, SC Dutton, EG Ogren, JA Valero, FPJ Kim, J Holben, BN TI Comparisons of aerosol optical depth and surface shortwave irradiance and their effect on the aerosol surface radiative forcing estimation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SKY RADIANCE MEASUREMENTS; INDIAN-OCEAN EXPERIMENT; ACE-ASIA; SUN PHOTOMETERS; EARTHS SURFACE; NETWORK; AERONET; INSTRUMENTATION; SUNPHOTOMETER; MODELS AB Column aerosol optical depth (AOD) and surface shortwave irradiance (SSI) measurements relevant to computation of the aerosol surface radiative forcing (DF) and forcing efficiency (beta) were taken as part of Aerosol Characterization Experiment-Asia (ACE-Asia) at the Gosan surface site in Korea in April 2001. We compare the AOD and SSI derived from three different types of Sun photometers and three sets of radiometers. We also estimate the Delta F and beta b using two methods and quantify the observational uncertainties of these parameters. A comparison of the AOD at 500 nm shows that the three Sun photometers generally agreed within 0.014 (mean), 0.0142 (bias), and 0.0298 (root mean square) for coincident observations. Over the course of the comparison, the mean differences between the SSI measurements were 1.6, 11.7, and 10.1 Wm(-2) for direct, diffuse and global irradiances, respectively. However, for both the AOD and the SSI comparisons, relatively high instantaneous differences between the instruments were apparent on days with heavy dust at the surface. The mean beta and associated deviations, which were estimated by the combinations of different instrument-derived AODs and SSIs, for simultaneous observation data at a 60 degrees solar zenith angle are -79.50 +/- 3.92 and -82.57 +/- 5.70 Wm(-2)/tau(500) for global(shaded) (sum of direct and diffuse irradiances) and global(unshaded) (measured by the unshaded pyranometer) irradiances, respectively. The uncertainties in beta associated with uncertainties in the AOD and SSI ( in parentheses) for globalshaded and globalunshaded irradiance are about 8.6% and 3.2% (10.7%), respectively. A 2% difference between the measured global irradiances for a given 9 days was translated into an uncertainty of 19% in Delta F. This difference in Delta F between instruments caused a 14% deviation in beta. C1 Seoul Natl Univ, Sch Earth & Environm Studies, Seoul 151742, South Korea. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Korea Meteorol Adm, Meteorol Res Inst, Seoul, South Korea. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kim, SW (reprint author), Seoul Natl Univ, Sch Earth & Environm Studies, 56-520 San 56-1, Seoul 151742, South Korea. EM anne.jefferson@noaa.gov RI Jefferson, Anne/K-4793-2012; Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 36 TC 13 Z9 14 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 6 PY 2005 VL 110 IS D7 AR D07204 DI 10.1029/2004JD004989 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916IH UT WOS:000228378100001 ER PT J AU Rakov, VA Kodali, V Crawford, DE Schoene, J Uman, MA Rambo, KJ Schnetzer, GH AF Rakov, VA Kodali, V Crawford, DE Schoene, J Uman, MA Rambo, KJ Schnetzer, GH TI Close electric field signatures of dart leader/return stroke sequences in rocket-triggered lightning showing residual fields SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TIME DERIVATIVES; MAGNETIC-FIELDS; FLORIDA; CHARGE; LEADER AB Vertical electric field waveforms due to dart leader/return stroke sequences measured on the ground 15 and 30 m from the negative lightning channel are used to examine the so-called residual electric field, the difference between the leader electric field change, and the following return stroke electric field change. At these distances, no residual field is expected if the return stroke neutralizes essentially all the charge deposited by the leader within a few hundred meters above ground. There is a clear tendency for strokes having larger peak currents to be associated with larger residual electric fields. The ratio of residual electric fields at 15 and 30 m suggests that the residual field varies as r(-1.5), where r is the horizontal distance from the lightning channel. The residual electric field is found from modeling to be associated with an equivalent point charge of the order of hundreds of microcoulombs to a few millicoulombs at a height of 15 to 30 m deposited by the leader but presumably left unneutralized by the return stroke. This residual point charge decays exponentially on a timescale of the order of milliseconds to tens of milliseconds. While the nature of the residual charge is unknown, it could be associated with small branches formed near the descending leader tip just prior to or during the attachment process. In long laboratory spark experiments, such branches have apparently been observed to lose their connection with the main channel. C1 Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. NASA, Kennedy Space Ctr, FL USA. RP Rakov, VA (reprint author), Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. EM rakov@ece.ufl.edu RI Rakov, Vladimir/A-8775-2009 OI Rakov, Vladimir/0000-0002-4582-9483 NR 18 TC 6 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 6 PY 2005 VL 110 IS D7 AR D07205 DI 10.1029/2004JD005417 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916IH UT WOS:000228378100003 ER PT J AU Bhasin, KB AF Bhasin, KB TI Interplanetary Internet SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Bhasin, KB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM kul.b.bhasin@grc.nasa.gov NR 0 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD APR 5 PY 2005 VL 47 IS 5 SI SI BP 599 EP 601 DI 10.1016/j.comnet.2004.08.007 PG 3 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 904TW UT WOS:000227521600001 ER PT J AU Rash, J Hogie, K Casasanta, R AF Rash, J Hogie, K Casasanta, R TI Internet technology for future space missions SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE global precipitation measurement (GPM) mission; Internet protocol (IP); mobile IP; operating missions as nodes on the Internet (OMNI); high-level data link control (HDLC) AB Ongoing work at National Aeronautics and Space Administration Goddard Space Flight Center (NASA/GSFC), seeks to apply standard Internet applications and protocols to meet the technology challenge of future satellite missions. Internet protocols and technologies are under study as a future means to provide seamless dynamic communication among heterogeneous instruments, spacecraft, ground stations, constellations of spacecraft, and science investigators. The primary objective is to design and demonstrate in the laboratory the automated end-to-end transport of files in a simulated dynamic space environment using off-the-shelf, low-cost, commodity-level standard applications and protocols. The demonstrated functions and capabilities will become increasingly significant in the years to come as both earth and space science missions fly more sensors and the present labor-intensive, mission-specific techniques for processing and routing data become prohibitive. This paper describes how an IP-based communication architecture can support all existing operations concepts and how it will enable some new and complex communication and science concepts. The authors identify specific end-to-end data flows from the instruments to the control centers and scientists, and then describe how each data flow can be supported using standard Internet protocols and applications. The scenarios include normal data downlink and command uplink as well as recovery scenarios for both onboard and ground failures. The scenarios are based on an Earth orbiting spacecraft with downlink data rates from 300 kbps to 4Mbps. Included examples are based on designs currently being investigated for potential use by the Global Precipitation Measurement (GPM) mission. (C) 2004 Elsevier B.V. All rights reserved. C1 Comp Sci Corp, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hogie, K (reprint author), Comp Sci Corp, Lanham, MD 20706 USA. EM keith.hogie@gsfe.nasa.gov NR 7 TC 2 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD APR 5 PY 2005 VL 47 IS 5 SI SI BP 651 EP 659 DI 10.1016/j.comnet.2004.08.003 PG 9 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 904TW UT WOS:000227521600003 ER PT J AU Hadjitheodosiou, M Zeng, H Nguyen, A Ellis, BL AF Hadjitheodosiou, M Zeng, H Nguyen, A Ellis, BL TI Flexible access for a space communications network with IP functionality SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE space communication; multiple access; satellite communications; TDMA ID SYSTEM AB The vision for the future space network involves a scenario where all scientific spacecraft form a distributed network to provide real-time information transfer to users on the ground. This scenario will require sensors and instruments on spacecraft to become addressable nodes in a communication network. To enable this vision, there is critical need for advanced communications and dynamic network connectivity to provide broad coverage and intelligent-based real-time data delivery to scientists. These new missions will introduce a number of complex routing, network control, scheduling, data management and communication problems that need to be studied in detail. We describe the potential advantages of a dynamic mission's operations concept and the need to develop a dynamic bandwidth allocation enabling more efficient use of the space resources. In this scenario, a number of spacecraft, each with several instruments on-board, are sending data to ground stations through the NASA relay system. Our objective is to provide an optimal or near-optimal t utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific QoS requirements for different service classes. We try to understand the traffic profiles that need to be supported and propose a suitable hybrid Time Division Multiple Access (TDMA)-based protocol. We formulate and study an assignment problem for optimal timeslot scheduling. By using simulation, the protocol performance is analyzed and compared with that of the existing static fixed-assignment scheme. We also address the benefits of increasing spacecraft availability using a Direct-to-Ground communications option that can be enabled in an IP-based network. By addressing these issues we try to contribute in the development of the next generation space network infrastructure that will serve as an enabler for better space exploration. (C) 2004 Elsevier B.V. All rights reserved. C1 Univ Maryland, ISR, Ctr Satellite & Hybrid Commun Networks, College Pk, MD 20742 USA. NASA, Glenn Res Ctr, Mission Network Appicat Branch, Cleveland, OH 44135 USA. RP Hadjitheodosiou, M (reprint author), Univ Maryland, ISR, Ctr Satellite & Hybrid Commun Networks, AV Williams Bldg, College Pk, MD 20742 USA. EM michalis@isr.umd.edu; zengh@isr.umd.edu; alextn@isr.umd.edu; brenda.l.ellis@nasa.gov NR 23 TC 1 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD APR 5 PY 2005 VL 47 IS 5 SI SI BP 679 EP 700 DI 10.1016/j.comnet.2004.08.009 PG 22 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 904TW UT WOS:000227521600005 ER PT J AU Clare, LP Gao, JL Jennings, EH Okino, C AF Clare, LP Gao, JL Jennings, EH Okino, C TI Space-based multi-hop networking SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE satellite networks; sensor networks; constellations; multi-hop relay ID ASSIGNMENT AB Many emerging applications will incorporate multiple spacecraft that form communications networks necessary to achieve coverage, latency and throughput requirements. Such networks may arise in the context of a space science mission consisting of distributed spacecraft performing multi-point sensing, or a global surveillance system serving military needs. Constellations of sensor spacecraft significantly benefit from incorporation of cross-link communications capabilities, thereby forming networks, by enabling continuous access to any/all spacecraft via a single ground contact, real-time coordinated observations, and autonomous in situ processing within a spatial neighborhood of spacecraft. Space-based networks may also be employed as relay infrastructure supporting (Earth, Moon, other planet) surface users engaged in various applications, such as space exploration. In this paper, we present an "L2 mesh" protocol for space-based sensor networks. Because of the large inter-spacecraft distances, directional antennas are used, with a single transceiver per spacecraft to achieve low cost. Orbital motion induces a dynamic albeit predictable geometry (and topology) among the spacecraft. One or more ground (base) stations are used; multiple ground stations are often required to ensure continuous network connectivity. Offered traffic patterns are general anycast to ground stations, and reverse-direction dissemination (for spacecraft commanding or "forward" relay). We present a technique that derives the link activation schedule (transmit/receive mode and communications neighbor selection) and route paths used for multi-hop relay through the network, leveraging the Florens and McEliece algorithm for tree networks. Highly efficient communications are achieved; in particular, the inherent tree structure enables accommodation of propagation delays that otherwise degrade the large delay-bandwidth links comprising space networks. An illustrative example is presented. Simulations demonstrate that the algorithm provides high throughput and low latency performance over general network configurations. An extension to the networking method is described that is traffic adaptive. Published by Elsevier B.V. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clare, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM loren.p.clare@jpl.nasa.gov; jay.l.gao@jpl.nasa.gov; esther.h.jennings@jpl.nasa; clayton.m.okino@jpl.nasa.gov NR 27 TC 5 Z9 6 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD APR 5 PY 2005 VL 47 IS 5 SI SI BP 701 EP 724 DI 10.1016/j.comnet.2004.08.004 PG 24 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 904TW UT WOS:000227521600006 ER PT J AU Beck, RA Vincent, RK Watts, DW Seibert, MA Pleva, DP Cauley, MA Ramos, CT Scott, TM Harter, DW Vickerman, M Irmies, D Tucholski, A Frantz, B Lindamood, G Lopez, I Follen, G Kollar, T Horowitz, J Griffin, R Gilstrap, R Johnson, M Freeman, K Banaag, C Kosmo, J Ross, A Groneman, K Graham, J Shillcutt, K Hirsh, R Howard, N Eppler, DB AF Beck, RA Vincent, RK Watts, DW Seibert, MA Pleva, DP Cauley, MA Ramos, CT Scott, TM Harter, DW Vickerman, M Irmies, D Tucholski, A Frantz, B Lindamood, G Lopez, I Follen, G Kollar, T Horowitz, J Griffin, R Gilstrap, R Johnson, M Freeman, K Banaag, C Kosmo, J Ross, A Groneman, K Graham, J Shillcutt, K Hirsh, R Howard, N Eppler, DB TI A space-based end-to-end prototype geographic information network for lunar and planetary exploration and emergency response (2002 and 2003 field experiments) SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE geographic information network; satellite imaging; remote sensing; Internet AB Communications and imaging experiments conducted in the Arizona desert during July of 2002 with the National Aeronautics and Space Administration (NASA) and the United States Geological Survey (USGS) helped to identify a fundamental suite of scientific instruments focused on surface composition and temperature determination for the calibration and validation of NASA and USGS spaceborne and airborne sensors and to integrate them with a hybrid mobile wireless and satellite network for lunar and planetary exploration and emergency response. The 2002 experiment focused on the exchange of remotely sensed and ground truth geographic information between analysts and field scientists. That experiment revealed several modifications that would enhance the performance and effectiveness of geographic information networks (GIN) for lunar and planetary exploration and emergency response. Phase 2 experiments conducted during June 2003 at the USGS Earth Resources and Observation Systems (EROS) Data Center's geologic imaging test site near Dinosaur National Monument in the NE Utah desert incorporated several of the lessons learned from the 2002 experiment and successfully added five major new components: (1) near-real-time hyperspectral and multispectral satellite image acquisition, (2) remotely controlled and coordinated mobile real-time ground sensor measurements during the imaging satellite overpass, (3) long-delay optimized Transmission Control Protocol/Internet Protocol TCP/IP protocols to improve network performance over geosynchronous communications satellite circuits, (4) distributed, multinode parallel computing on NASA's Internet Power GRID (IPG), and (5) near-real-time validation of satellite imagery as part of a successful test of the NASA-USGS National Emergency Mapping Information System. (C) 2004 Elsevier B.V. All rights reserved. C1 Cent State Univ, CJ McLin Labs 107, Int Ctr Water Resources Management, Wilberforce, OH 45384 USA. Bowling Green State Univ, Coll Arts & Sci, Dept Geol, Bowling Green, OH 43403 USA. Wright State Univ, Dept Geol Sci, Dayton, OH 45435 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Beck, RA (reprint author), Cent State Univ, CJ McLin Labs 107, Int Ctr Water Resources Management, Wilberforce, OH 45384 USA. EM rbeck@centralstate.edu RI Vincent, Robert/A-9036-2009; OI Vincent, Robert/0000-0002-2814-4589 NR 22 TC 3 Z9 3 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD APR 5 PY 2005 VL 47 IS 5 SI SI BP 765 EP 783 DI 10.1016/j.comnet.2004.08.010 PG 19 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 904TW UT WOS:000227521600009 ER PT J AU Douglas, RB Parker, VT Cullings, KW AF Douglas, RB Parker, VT Cullings, KW TI Belowground ectomycorrhizal community structure of mature lodgepole pine and mixed conifer stands in Yellowstone National Park SO FOREST ECOLOGY AND MANAGEMENT LA English DT Article DE ectomycorrhizae; soil chemistry; community structure; ITS-RFLP; Yellowstone ID NITROGEN DEPOSITION GRADIENT; SUB-ALPINE FORESTS; PSEUDOTSUGA-MENZIESII; FUNGAL COMMUNITIES; MYCORRHIZAL FUNGI; SEQUENCE DATABASE; MURICATA FOREST; CONTORTA STAND; DIVERSITY; SEEDLINGS AB Forest development patterns following wildfire are known to influence the physical and chemical attributes of soils at different points in time, and are further thought to influence ectomycorrhizal (ECM) community structure. We used molecular methods to compare belowground ECM species richness, composition, and abundance between adjacent stands of homogenous lodgepole pine (established after a fire around 1867) and old growth mixed conifer (around 300 years old) in Yellowstone National Park (YNP). In each stand type, we collected soil cores to both identify mycorrhizae and assess soil chemistry. Although no statistical difference was observed in the mean number of ECM root tips per core between stand types, the total number of species identified (81 versus 35) and the mean number of species per core (8.7 +/- 0.5 versus 2.5 +/- 0.3) were significantly higher in lodgepole pine. Species compositions were widely disparate between stands where only four of 112 species were shared. Soil analysis revealed that mixed conifer was significantly lower in mean pH, but higher in mean organic matter, potassium, phosphorus, and ammonium when compared to lodgepole pine. Although analysis of covariance did not statistically demonstrate that soil chemistry is driving ECM community structure with certainty, our data are, nonetheless, consistent with this hypothesis. Our data further suggest that fungal richness declines and composition shifts some time after Engelmann spruce and subalpine fir colonize mature lodgepole pine stands, and that time since last wildfire influences soil chemistry in this system. Moreover, because of data limitations, future field experiments will be necessary to determine if soil chemistry, as well as other biotic and abiotic factors not examined in this study, is a primary influence on ECM community structure at our study site in YNP. (c) 2005 Elsevier B.V. All rights reserved. C1 San Francisco State Univ, Dept Biol, San Francisco, CA 94132 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mendocino Redwood Co, 32600 Holquist Lane,POB 489, Fort Bragg, CA 95437 USA. EM rdouglas@mendoco.com NR 55 TC 24 Z9 25 U1 3 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1127 EI 1872-7042 J9 FOREST ECOL MANAG JI For. Ecol. Manage. PD APR 5 PY 2005 VL 208 IS 1-3 BP 303 EP 317 DI 10.1016/j.foreco.2004.12.011 PG 15 WC Forestry SC Forestry GA 909LF UT WOS:000227860700021 ER PT J AU Kahn, BH Liou, KN Lee, SY Fishbein, EF DeSouza-Machado, S Eldering, A Fetzer, EJ Hannon, SE Strow, LL AF Kahn, BH Liou, KN Lee, SY Fishbein, EF DeSouza-Machado, S Eldering, A Fetzer, EJ Hannon, SE Strow, LL TI Nighttime cirrus detection using Atmospheric Infrared Sounder window channels and total column water vapor SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID METEOROLOGICAL SATELLITE IMAGERY; NONSPHERICAL ICE CRYSTALS; CLOUD OPTICAL-THICKNESS; THIN CIRRUS; TROPICAL TROPOPAUSE; MU-M; ABSORPTION PROPERTIES; RADIATIVE-TRANSFER; AVHRR DATA; CLEAR-SKY AB A method of cirrus detection at nighttime is presented that utilizes 3.8 and 10.4 mu m infrared (IR) window brightness temperature differences (dBT) and total column precipitable water (PW) measurements. This technique is applied to the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit A (AMSU-A) instrument suite on board EOS-Aqua, where dBT is determined from sets of carefully selected AIRS window channels, while PW is derived from the synergistic AIRS and AMSU-A water vapor retrievals. Simulated and observed dBT for a particular value of PW are not constant; several physical factors impact dBT, including the variability in temperature and relative humidity profiles, surface emissivity, instrument noise, and skin/near-surface air temperature differences. We simulate clear-sky dBT over a realistic range of PWs using 8350 radiosondes that have varying temperature and relative humidity profiles. Thresholds between cloudy and uncertain sky conditions are derived once the scatter in the clear-sky dBT is determined. Simulations of optically thin cirrus indicate that this technique is most sensitive to cirrus optical depth in the 10 mum window of 0.1-0.15 or greater over the tropical and subtropical oceans, where surface emissivity and skin/near-surface air temperature impacts on the IR radiances are minimal. The method at present is generally valid over oceanic regions only, specifically, the tropics and subtropics. The detection of thin cirrus, and other cloud types, is validated using observations at the Atmospheric Radiation Measurement (ARM) program site located at Manus Island in the tropical western Pacific for 89 coincident EOS-Aqua overpasses. Even though the emphasis of this work is on the detection of thin cirrus at nighttime, this technique is sensitive to a broad cloud morphology. The cloud detection technique agrees with ARM-detected clouds 82-84% of the time, which include thin cirrus, as well as other cloud types. Most of the disagreements are well explained by AIRS footprint-scale heterogeneity compared to ARM point measurements, cirrus overlying lower-layer water clouds, possible mixed phase microphysics in midlevel clouds, and significant IR channel noise for cold BT scenes over deep convective towers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Dept Phys, Baltimore, MD 21250 USA. Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM briank@atmos.ucla.edu NR 67 TC 18 Z9 18 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 2 PY 2005 VL 110 IS D7 AR D07203 DI 10.1029/2004JD005430 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916DY UT WOS:000228366800004 ER PT J AU Kato, S Loeb, NG AF Kato, S Loeb, NG TI Top-of-atmosphere shortwave broadband observed radiance and estimated irradiance over polar regions from Clouds and the Earth's Radiant Energy System (CERES) instruments on Terra SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANGULAR-DISTRIBUTION MODELS; MEASURING MISSION SATELLITE; RADIATIVE FLUX ESTIMATION; BIDIRECTIONAL REFLECTANCE; SEA-ICE; OPTICAL-PROPERTIES; SPECTRAL ALBEDO; ANTARCTIC SNOW; PART I; ERBE AB Empirical angular distribution models for estimating top-of-atmosphere shortwave irradiances from radiance measurements over permanent snow, fresh snow, and sea ice are developed using CERES measurements on Terra. Permanent snow angular distribution models depend on cloud fraction, cloud optical thickness, and snow brightness. Fresh snow and sea ice angular distribution models depend on snow and sea ice fraction, cloud fraction, cloud optical thickness, and snow and ice brightness. These classifications lead to 10 scene types for permanent snow and 25 scene types for fresh snow and sea ice. The average radiance over clear-sky permanent snow is more isotropic with satellite viewing geometry than that over overcast permanent snow. On average, the albedo of clear-sky permanent snow varies from 0.65 to 0.68 for solar zenith angles between 60 degrees and 80 degrees, while the corresponding albedo of overcast scenes varies from 0.70 to 0.73. Clear-sky permanent snow albedos over Antarctica estimated from two independent angular distribution models are consistent to within 0.6%, on average. Despite significant variability in sea ice optical properties with season, the estimated mean relative albedo error is -1.0% for very dark sea ice and 0.1% for very bright sea ice when albedos derived from different viewing angles are averaged. The estimated regional root-mean-square (RMS) relative albedo error is 5.6% and 2.6% when the sea ice angular distribution models are applied to a region that contains very dark and very bright sea ice, respectively. Similarly, the estimated relative albedo bias error for fresh snow is -0.1% for very dark snow scenes and 0.1% for very bright snow scenes. The estimated regional RMS relative albedo error is 3.5% and 5.0% when angular distribution models are applied to a region that contains very dark and very bright fresh snow, respectively. These error estimates are only due to angular distribution model error and do not include the error caused by scene identification. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Kato, S (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM s.kato@larc.nasa.gov; n.g.loeb@larc.nasa.gov NR 41 TC 26 Z9 26 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 2 PY 2005 VL 110 IS D7 AR D07202 DI 10.1029/2004JD005308 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916DY UT WOS:000228366800003 ER PT J AU Argus, DF Heflin, MB Peltzer, G Crampe, F Webb, FH AF Argus, DF Heflin, MB Peltzer, G Crampe, F Webb, FH TI Interseismic strain accumulation and anthropogenic motion in metropolitan Los Angeles SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SAN-ANDREAS FAULT; 1999 HECTOR MINE; FIELD POSTSEISMIC DEFORMATION; CURRENT PLATE MOTIONS; BLIND-THRUST-FAULT; SOUTHERN CALIFORNIA; VENTURA-BASIN; NORTHRIDGE EARTHQUAKE; LANDERS-EARTHQUAKE; GEODETIC MEASUREMENT AB We use global positioning system (GPS) geodesy and synthetic aperture radar (SAR) interferometry to distinguish between interseismic strain accumulation and anthropogenic motion in metropolitan Los Angeles. We establish a relationship between horizontal and vertical seasonal oscillations of the Santa Ana aquifer, use this relationship to infer cumulative horizontal anthropogenic motions from cumulative vertical motions caused by water and oil resource management, and estimate horizontal interseismic velocities corrected for anthropogenic effects. Vertical anthropogenic rates from 1992 to 1999 are slower than 3 mm yr(-1) in the Santa Ana and San Gabriel aquifers and faster than 5 mm yr(-1) in the Chino aquifer and in many oil fields. Inferred horizontal anthropogenic velocities are faster than 1 mm yr(-1) at 18 of 46 GPS sites. Northern metropolitan Los Angeles is contracting, with the 25 km south of the San Gabriel Mountains shortening at 4.5 +/- 1 mm yr(-1) (95% confidence limits). The thrust fault in an elastic edge dislocation model of the observed strain is creeping at 9 +/- 2 mm yr(-1) beneath and north of a position 6 +/- 2 km deep and 8 +/- 8 km north of downtown Los Angeles. The model fault is near the Los Angeles segment of the Puente Hills thrust but south of the Sante Fe Springs segment of the thrust. Disagreement between the 6 km locking depth in the model and the 15 km seismogenic depth inferred from earthquakes suggests that the elastic continuum model may be unsatisfactory; models with different stiffnesses of sedimentary basin and crystalline basement must be investigated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Div Earth & Space Sci, Los Angeles, CA 90095 USA. RP CALTECH, Jet Prop Lab, Mail Stop 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM donald.f.argus@jpl.nasa.gov RI Argus, Donald/F-7704-2011 NR 66 TC 62 Z9 63 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 2 PY 2005 VL 110 IS B4 AR B04401 DI 10.1029/2003JB002934 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916FC UT WOS:000228369800001 ER PT J AU Landis, GA LaMarre, C Colozza, A AF Landis, GA LaMarre, C Colozza, A TI Venus atmospheric exploration by solar aircraft SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd International-Astronautical-Federation Congress CY OCT 10-19, 2002 CL HOUSTON, TX SP Int Astronaut Federat AB The Venus atmosphere is a favorable environment for flying powered aircraft. The atmospheric pressure makes flight much easier than on planets such as Mars. Above the clouds, solar energy is available in abundance on Venus, and the slow rotation of Venus allows a solar airplane to be designed for flight within continuous sunlight. The atmosphere between 50 and 75 km on Venus is one of the most dynamic and interesting regions of the planet. The challenge for a Venus aircraft will be the fierce winds and caustic atmosphere. In order to remain on the sunlit side of Venus, an exploration aircraft will have to be capable of sustained flight at or above the wind speed. An aircraft would be a powerful tool for exploration. By learning how Venus can be so similar to Earth, and yet so different, we will learn to better understand the climate and geological history of the Earth. Published by Elsevier Ltd. C1 NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Illinois, Dept Aeronaut Engn, Champaign, IL USA. RP Landis, GA (reprint author), NASA, John Glenn Res Ctr, Mailstop 302-1, Cleveland, OH 44135 USA. EM geoffrey.landis@grc.nasa.gov NR 13 TC 12 Z9 13 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD APR PY 2005 VL 56 IS 8 BP 750 EP 755 DI 10.1016/j.actaastro.2004.12.001 PG 6 WC Engineering, Aerospace SC Engineering GA 920SO UT WOS:000228710600005 ER PT J AU Chamitoff, G James, G Barker, D Dershowitz, A AF Chamitoff, G James, G Barker, D Dershowitz, A TI Martian resource locations: Identification and optimization SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd International-Astronautical-Federation Congress CY OCT 10-19, 2002 CL HOUSTON, TX SP Int Astronaut Federat AB The identification and utilization of in situ Martian natural resources is the key to enable cost-effective long-duration missions and permanent human settlements on Mars. This paper presents a powerful software tool for analyzing Martian data from all sources, and for optimizing mission site selection based on resource collocation. This program, called Planetary Resource Optimization and Mapping Tool (PROMT), provides a wide range of analysis and display functions that can be applied to raw data or imagery. Thresholds, contours, custom algorithms, and graphical editing are some of the various methods that can be used to process data. Output maps can be created to identify surface regions on Mars that meet any specific criteria. The use of this tool for analyzing data, generating maps, and collocating features is demonstrated using data from the Mars Global Surveyor and the Odyssey spacecraft. The overall mission design objective is to maximize a combination of scientific return and self-sufficiency based on utilization of local materials. Landing site optimization involves maximizing accessibility to collocated science and resource features within a given mission radius. Mission types are categorized according to duration, energy resources, and in situ resource utilization. Preliminary optimization results are shown for a number of mission scenarios. Published by Elsevier Ltd. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. MAXD Inc, Houston, TX 77059 USA. Exponent, Los Angeles, CA 90066 USA. RP Chamitoff, G (reprint author), NASA, Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 USA. EM chamitoff@jsc.nasa.gov; george.h.james1@jsc.nasa.gov; barker891@cs.com; dersh@alum.mit.edu OI Barker, Donald/0000-0001-5627-7197 NR 10 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD APR PY 2005 VL 56 IS 8 BP 756 EP 769 DI 10.1016/j.actaastro.2004.12.004 PG 14 WC Engineering, Aerospace SC Engineering GA 920SO UT WOS:000228710600006 ER PT J AU Peters, BT Bloomberg, JJ AF Peters, BT Bloomberg, JJ TI Dynamic visual acuity using "far'' and "near'' targets SO ACTA OTO-LARYNGOLOGICA LA English DT Article DE canal function; compensatory gaze mechanisms; dynamic visual acuity; otolith function; target distance ID UNILATERALLY VESTIBULOPATHIC HUMANS; VESTIBULAR HYPOFUNCTION; ROTATION; HEAD; STRATEGIES; TRANSIENT; WALKING AB Conclusions. DVA may be useful for assessing the functional consequences of an impaired gaze stabilization mechanism or for testing the effectiveness of a rehabilitation paradigm. Because target distance influences the relative contributions of canal and otolith inputs, the ability to measure DVA at near and far viewing distances may also lead to tests that will independently assess canal and otolith function. Objective. To present and test a methodology that uses dynamic visual acuity ( DVA) to assess the efficacy of compensatory gaze mechanisms during a functionally relevant activity that differentially measures canal and otolith function. Material and methods. The effect of treadmill walking at a velocity of 1.79 m/s on subjects' visual acuity was assessed at each of two viewing distances. A custom-written threshold determination program was used to display Landolt C optotypes on a laptop computer screen during a "far'' ( 4 m) target condition and on a micro-display for a "near'' ( 50 cm) target condition. The walking acuity scores for each target distance were normalized by subtracting a corresponding acuity measure obtained while standing still on the treadmill belt. Results. As predicted by subjective reports of relative target motion, the decrease in visual acuity was significantly greater (p< 0.00001) for the near compared to the far condition. C1 Wyle Labs, Neurosci Lab, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Peters, BT (reprint author), Wyle Labs, Neurosci Lab, 1290 Hercules Dr,Suite 120, Houston, TX 77058 USA. EM bpeters@ems.jsc.nasa.gov NR 16 TC 20 Z9 21 U1 0 U2 5 PU TAYLOR & FRANCIS AS PI OSLO PA PO BOX 12 POSTHUSET, NO-0051 OSLO, NORWAY SN 0001-6489 J9 ACTA OTO-LARYNGOL JI Acta Oto-Laryngol. PD APR PY 2005 VL 125 IS 4 BP 353 EP 357 DI 10.1080/00016480410024631 PG 5 WC Otorhinolaryngology SC Otorhinolaryngology GA 914AK UT WOS:000228196600003 PM 15823804 ER PT J AU Watkins, K Smith, N AF Watkins, K Smith, N TI AIAA Strat Talk: A conversation with Nicole Smith about AIAA'S Strategic Direction SO AEROSPACE AMERICA LA English DT Editorial Material C1 AIAA Strateg Planning & Commun, Reston, VA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. AIAA Young Profess Liaison Board Directors, Reston, VA USA. RP Watkins, K (reprint author), AIAA Strateg Planning & Commun, Reston, VA USA. EM Nicole.Smith-1@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD APR PY 2005 VL 43 IS 4 BP B5 EP B5 PG 1 WC Engineering, Aerospace SC Engineering GA 915CY UT WOS:000228276400014 ER PT J AU Balakumar, P Zhao, HW Atkins, H AF Balakumar, P Zhao, HW Atkins, H TI Stability of hypersonic boundary layers over a compression corner SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 32nd Fluid Dynamics Conference CY JUN 24-26, 2002 CL St Louis, MO SP Amer Inst Aeronaut & Astronaut ID SEPARATION; LAMINAR; FLOWS AB The stability of hypersonic boundary layers over a compression corner is investigated numerically. To compute the shock and the interaction of the shock with the instability waves, the simulation solves the three-dimensional Navier-Stokes equations using a high-order, weighted, essentially nonoscillatory shock-capturing scheme. After computing the mean flowfield, the procedure then superimposes two-dimensional unsteady disturbances at the inflow and computes the evolution of these disturbances in downstream direction. Because of the interaction of the shock with the boundary layer, a separation bubble forms at the corner, and two compression waves form near the separation and reattachment points. These compression waves merge farther away from the boundary layer to form a shock. The investigation of the evolution of the second mode shows three distinct regions. One is upstream of the separation bubble where the disturbances grow in agreement with the linear theory of similarity boundary layers. The second region is the separation bubble region where the disturbances remain neutral. These disturbances reside above the separation bubble and do not penetrate the separated region. The third region is downstream of the separation bubble where the disturbances again grow exponentially as in boundary layers. C1 NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. Old Dominion Univ, Dept Aerosp Engn, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Balakumar, P (reprint author), NASA, Langley Res Ctr, Flow Phys & Control Branch, MS 170, Hampton, VA 23681 USA. NR 17 TC 8 Z9 8 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 2005 VL 43 IS 4 BP 760 EP 767 DI 10.2514/1.3479 PG 8 WC Engineering, Aerospace SC Engineering GA 914SC UT WOS:000228246900007 ER PT J AU Zhu, LF Kim, HS Chattopadhyay, A Goldberg, RK AF Zhu, LF Kim, HS Chattopadhyay, A Goldberg, RK TI Improved transverse shear calculations for rate-dependent analyses of polymer matrix composites SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 45th Structures, Structural Dynamics and Materials Conference CY APR 19-22, 2004 CL Palm Springs, CA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID PLATES AB A numerical procedure has been developed to investigate the nonlinear and strain-rate-dependent deformation response of polymer matrix composite laminated plates under high strain-rate impact loadings. A recently developed strength of materials based micromechanics model, incorporating a set of nonlinear, strain-rate-dependent constitutive equations for the polymer matrix, is extended to account for the transverse shear effects during impact. Four different assumptions of transverse shear deformation are investigated to improve the developed strain-rate-de pendent micromechanics model. The validities of these assumptions are investigated using numerical and theoretical approaches. A method to determine through the thickness strain and transverse Poisson's ratio of the composite is developed. The revised micromechanics; model is then implemented into a higher-order laminated plate theory that is modified to include the effects of inelastic strains. Parametric studies are conducted to investigate the mechanical response of composite plates under high strain-rate loadings. Results show that the transverse shear stresses cannot be neglected in the impact problem. A significant level of strain-rate dependency and material nonlinearity is found in the deformation response of representative composite specimens. C1 Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. NASA, John H Glenn Res Ctr, Life Predict Branch, Struct Div, Cleveland, OH 44135 USA. RP Arizona State Univ, Dept Mech & Aerosp Engn, Tempe, AZ 85287 USA. RI Kim, Heung Soo /F-6611-2011 OI Kim, Heung Soo /0000-0001-7057-5174 NR 19 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 EI 1533-385X J9 AIAA J JI AIAA J. PD APR PY 2005 VL 43 IS 4 BP 895 EP 905 DI 10.2514/1.11793 PG 11 WC Engineering, Aerospace SC Engineering GA 914SC UT WOS:000228246900020 ER PT J AU Spackman, TN Abel, MD Schlegel, TT AF Spackman, TN Abel, MD Schlegel, TT TI Twelve-lead high-frequency QRS electrocardiography during anesthesia in healthy subjects SO ANESTHESIA AND ANALGESIA LA English DT Article ID CORONARY-ARTERY-DISEASE; MYOCARDIAL-ISCHEMIA; OCCLUSION; STANDARD AB Analysis of the high-frequency (HF) components of the QRS complex has been shown to be a more sensitive indicator of myocardial ischemia and infarction than conventional ST segment analysis in settings outside of the operating room. In this study, we documented the effect of general anesthesia on HF QRS analysis in healthy patients as the first step in determining the potential of this technique for monitoring anesthetized patients. HF QRS electrocardiograms (ECGs) were obtained from all 12 ECG leads in 30 healthy subjects before and after the induction of anesthesia. When compared with preinduction values, there were significant postinduction changes in multiple variables of the HF QRS in many leads studied that were within previously described normal limits. Additional study is needed to understand the potential of this monitoring technique for enhancing detection of myocardial ischemia in the anesthetized population. C1 Mayo Clin, Coll Med, Dept Anesthesiol, Div Cardiovasc Thorac Surg, Rochester, MN 55905 USA. NASA, Lyndon B Johnson Space Ctr, Neuroauton Lab, Houston, TX 77058 USA. RP Spackman, TN (reprint author), Mayo Clin, Coll Med, Dept Anesthesiol, Div Cardiovasc Thorac Surg, 200 1st St SW, Rochester, MN 55905 USA. EM spackman.thomas@mayo.edu NR 12 TC 3 Z9 3 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0003-2999 EI 1526-7598 J9 ANESTH ANALG JI Anesth. Analg. PD APR PY 2005 VL 100 IS 4 BP 1043 EP 1047 DI 10.1213/01.ANE.0000146436.77600.07 PG 5 WC Anesthesiology SC Anesthesiology GA 908MZ UT WOS:000227792400022 PM 15781519 ER PT J AU Cullings, K Raleigh, C New, MH Henson, J AF Cullings, K Raleigh, C New, MH Henson, J TI Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID EXPERIMENTAL GRASSLAND COMMUNITY; CARBON-SOURCE UTILIZATION; FUNCTIONAL BIODIVERSITY; MYCORRHIZAL SYMBIOSIS; MICROBIAL COMMUNITIES; ENVIRONMENTAL-STRESS; UTILIZATION PATTERNS; PINYON PINES; PLANT; ECTOMYCORRHIZAE AB Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems. C1 NASA, Ames Res Ctr, Mountain View, CA 94035 USA. NASA, Headquarters, Washington, DC 20546 USA. Montana State Univ, Dept Microbiol, Bozeman, MT 59717 USA. RP Cullings, K (reprint author), NASA, Ames Res Ctr, Mountain View, CA 94035 USA. EM kcullings@mail.arc.nasa.gov NR 53 TC 13 Z9 14 U1 1 U2 18 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD APR PY 2005 VL 71 IS 4 BP 1996 EP 2000 DI 10.1128/AEM.71.4.1996-2000.2005 PG 5 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 915UY UT WOS:000228338000043 PM 15812031 ER PT J AU Sun, WB Loeb, NG Tanev, S Videen, G AF Sun, WB Loeb, NG Tanev, S Videen, G TI Finite-difference time-domain solution of light scattering by an infinite dielectric column immersed in an absorbing medium SO APPLIED OPTICS LA English DT Article; Proceedings Paper CT Biomedical Topical Meeting CY APR, 2004 CL Miami Beach, FL SP Opt Soc Amer ID PERFECTLY MATCHED LAYER; MIE-SCATTERING; SPHERICAL-PARTICLES; MAXWELLS EQUATIONS; NUMERICAL-SOLUTION; EXTINCTION; SPHERES AB The two-dimensional (2-D) finite-difference time-domain (FDTD) method is applied to calculate light scattering and absorption by an arbitrarily shaped infinite column embedded in an absorbing dielectric medium. A uniaxial perfectly matched layer (UPML) absorbing boundary condition is used to truncate the computational domain. The single-scattering properties of the infinite column embedded in the absorbing medium, including scattering phase functions and extinction and absorption efficiencies, are derived by use of an area integration of the internal field. An exact solution for light scattering and absorption by a circular cylinder in an absorbing medium is used to examine the accuracy of the 2-D UPML FDTD code. With use of a cell size of 1/120 incident wavelength in the FDTD calculations, the errors in the extinction and absorption efficiencies and asymmetry factors from the 2-D UPML FDTD are generally smaller than similar to 0.1%. The errors in the scattering phase functions are typically smaller than similar to 4%. With the 2-D UPML FDTD technique, light scattering and absorption by long noncircular columns embedded in absorbing media can be accurately solved. (c) 2005 Optical Society of America. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Vitesse Reskilling Canada, Ottawa, ON K1A 0R6, Canada. USA, Res Lab, Adelphi, MD 20783 USA. RP Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. EM w.sun@larc.nasa.gov NR 25 TC 10 Z9 10 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD APR 1 PY 2005 VL 44 IS 10 BP 1977 EP 1983 DI 10.1364/AO.44.001977 PG 7 WC Optics SC Optics GA 911WG UT WOS:000228036600025 PM 15813534 ER PT J AU Hoehler, TM AF Hoehler, TM TI Cretaceous Park? A commentary on microbial paleomics SO ASTROBIOLOGY LA English DT Editorial Material ID ANCIENT DNA; BACTERIUM; SEDIMENTS; BIOSPHERE; SEQUENCE C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Hoehler, TM (reprint author), NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. EM tori.m.hoehler@nasa.gov NR 22 TC 5 Z9 6 U1 0 U2 2 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2005 VL 5 IS 2 BP 95 EP 99 DI 10.1089/ast.2005.5.95 PG 5 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 916UZ UT WOS:000228413100001 PM 15815162 ER PT J AU Cockell, CS Schuerger, AC Billi, D Friedmann, EI Panitz, C AF Cockell, CS Schuerger, AC Billi, D Friedmann, EI Panitz, C TI Effects of a simulated martian UV flux on the cyanobacterium, Chroococcidiopsis sp 029 SO ASTROBIOLOGY LA English DT Article ID HAWAIIAN PALAGONITIC SOIL; BACILLUS-SUBTILIS SPORES; SPACECRAFT SURFACES; MAGNETIC-PROPERTIES; ESTERASE-ACTIVITY; SOLAR-RADIATION; EARLY EARTH; MARS; PHYCOBILIPROTEINS; DEGRADATION AB Dried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under I mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars. C1 British Antarctic Survey, Cambridge CB1 3AR, England. Univ Florida, Dept Plant Pathol, Space Life Sci Lab, Kennedy Space Ctr, Gainesville, FL 32611 USA. Univ Roma Tor Vergata, Dept Biol, Rome, Italy. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. German Aerosp Ctr, Inst Aerosp Med, Cologne, Germany. RP Cockell, CS (reprint author), British Antarctic Survey, High Croos Madingley Rd, Cambridge CB1 3AR, England. EM ccockell@ccockell.go-plus.net NR 40 TC 80 Z9 85 U1 0 U2 13 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2005 VL 5 IS 2 BP 127 EP 140 DI 10.1089/ast.2005.5.127 PG 14 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 916UZ UT WOS:000228413100003 PM 15815164 ER PT J AU Grymes, R AF Grymes, R TI NAI meeting: The challenges SO ASTROBIOLOGY LA English DT Editorial Material C1 NASA, Astrobiol Inst, Washington, DC 20546 USA. RP Grymes, R (reprint author), NASA, Astrobiol Inst, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD APR PY 2005 VL 5 IS 2 BP 168 EP 168 PG 1 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 916UZ UT WOS:000228413100006 ER PT J AU Belle, KE Howell, SB Mukai, K Szkody, P Nishikida, K Ciardi, DR Fried, RE Oliver, JP AF Belle, KE Howell, SB Mukai, K Szkody, P Nishikida, K Ciardi, DR Fried, RE Oliver, JP TI Simultaneous X-ray and optical observations of EX Hydrae SO ASTRONOMICAL JOURNAL LA English DT Article DE accretion, accretion disks; novae, cataclysmic variables; stars : individual ( EX Hydrae); X-rays : stars ID CATACLYSMIC VARIABLES; RADIAL-VELOCITY; WHITE-DWARF; SPECTROSCOPY; MASS; DENSITY; CHANDRA; HYA AB The intermediate polar, EX Hydrae, was the object of a large simultaneous multiwavelength observational campaign during 2000 May - June. Here we present the Rossi X-Ray Timing Explorer photometry and optical photometry and spectroscopy from ground-based observatories obtained as part of this campaign. Balmer line radial velocities and Doppler maps provide evidence for an extended bulge along the outer edge of the accretion disk and some form of extended/overflowing material originating from the hot spot. In addition, the optical binary eclipse possesses an extended egress shoulder, an indication that an additional source ( other than the white dwarf) is coming out of eclipse. We also compare the X-ray and optical results with the results obtained from the EUV and UV observations from the multiwavelength data set. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. WIYN Observ, Tucson, AZ 85726 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Braeside Observ, Flagstaff, AZ 86002 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. RP Belle, KE (reprint author), Los Alamos Natl Lab, X-2 MS B227, Los Alamos, NM 87545 USA. EM belle@lanl.gov; howell@noao.edu; mukai@milkyway.gsfc.nasa.gov; szkody@astro.washington.edu; kaori@ssl.berkeley.edu; ciardi@ipac.caltech.edu; oliver@astro.ufl.edu OI Ciardi, David/0000-0002-5741-3047 NR 20 TC 12 Z9 12 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2005 VL 129 IS 4 BP 1985 EP 1992 DI 10.1086/428487 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 907TU UT WOS:000227741700017 ER PT J AU Corcoran, MF AF Corcoran, MF TI X-ray monitoring of eta carinae: Variations on a theme SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : general; stars : early-type; stars : individual ( ~ Carinae); X-rays : stars ID LIGHT-CURVE; VARIABILITY; STAR AB We present monitoring observations by the Rossi X-Ray Timing Explorer of the 2 - 10 keV X-ray emission from the supermassive star eta Carinae from 1996 through late 2003. These data cover more than one of the stellar variability cycles in temporal detail and include especially detailed monitoring through two X-ray minima. We compare the current X-ray minimum, which began on 2003 June 29, with the previous X-ray minimum, which began on 1997 December 15, and refine the X-ray period to 2024 days. We examine the variations in the X-ray spectrum with phase and with time, and also refine our understanding of the X-ray "peaks," which have a quasi period of 84 days, with significant variation. Cycle-to-cycle differences are seen in the level of X-ray intensity and in the detailed variations of the X-ray flux on the rise to maximum just prior to the X-ray minimum. Despite these differences, the similarities between the decline to minimum, the duration of the minimum, and correlated variations of the X-ray flux and other measures throughout the electromagnetic spectrum leave little doubt that the X-ray variation is strictly periodic and produced by orbital motion as the wind from eta Carinae collides with the wind of an otherwise unseen companion. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 23 TC 100 Z9 100 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 2005 VL 129 IS 4 BP 2018 EP 2025 DI 10.1086/428756 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 907TU UT WOS:000227741700020 ER PT J AU Farinelli, R Frontera, F Zdziarski, AA Stella, L Zhang, SN van der Klis, M Masetti, N Amati, L AF Farinelli, R Frontera, F Zdziarski, AA Stella, L Zhang, SN van der Klis, M Masetti, N Amati, L TI The transient hard X-ray tail of GX 17+2: New BeppoSAX results SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : GX 17+2; stars : neutron; X-rays : binaries; accretion, accretion disks ID ENERGY CONCENTRATOR SPECTROMETER; BROAD-BAND SPECTRUM; CYGNUS X-2; ASTRONOMY SATELLITE; MULTIWAVELENGTH CAMPAIGN; SCORPIUS X-1; ON-BOARD; RXTE OBSERVATIONS; TIMING BEHAVIOR; GAMMA-RAYS AB We report on results of two BeppoSAX observations of the Z source GX 17+ 2. In both cases the source is in the horizontal branch of the colour- intensity diagram. The persistent continuum can be fit by two- component models consisting of a blackbody plus a Comptonization spectrum. With one of these models, two solutions for the blackbody temperature of both the observed and seed photons for Comptonization are equally accepted by the data. In the first observation, when the source is on the left part of the horizontal branch, we observe a hard tail extending up to 120 keV, while in the second observation, when the source moves towards right in the same branch, the tail is no longer detected. The hard (greater than or similar to 30 keV) X- ray emission can be modeled either by a simple power- law with photon index Gamma similar to 2.8, or assuming Comptonization of similar to 1 keV soft photons off a hybrid thermal plus non- thermal electron plasma. The spectral index of the non- thermal injected electrons is p similar to 1.7. The observation of hard X- ray emission only in the left part of the horizontal branch could be indicative of the presence of a threshold in the accretion rate above which the hard tail disappears. An emission line at 6.7 keV with equivalent width similar to 30 eV is also found in both observations. We discuss these results and their physical implications. C1 Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. CNR, Sez Bologna, Ist Astrofis Spaziale & Fis Cosm, I-40129 Bologna, Italy. Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Osserv Astron Roma, I-00040 Monte Porzio Catone, Italy. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. RP Farinelli, R (reprint author), Univ Ferrara, Dipartimento Fis, Via Paradiso 12, I-44100 Ferrara, Italy. EM farinelli@fe.infn.it RI Amati, Lorenzo/N-5586-2015; OI Amati, Lorenzo/0000-0001-5355-7388; Masetti, Nicola/0000-0001-9487-7740 NR 53 TC 29 Z9 29 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2005 VL 434 IS 1 BP 25 EP 34 DI 10.1051/0004-6361:20041567 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912RN UT WOS:000228097300005 ER PT J AU Vanzella, E Cristiani, S Dickinson, M Kuntschner, H Moustakas, LA Nonino, M Rosati, P Stern, D Cesarsky, C Ettori, S Ferguson, HC Fosbury, RAE Giavalisco, M Haase, J Renzini, A Rettura, A Serra, P AF Vanzella, E Cristiani, S Dickinson, M Kuntschner, H Moustakas, LA Nonino, M Rosati, P Stern, D Cesarsky, C Ettori, S Ferguson, HC Fosbury, RAE Giavalisco, M Haase, J Renzini, A Rettura, A Serra, P CA GOODS Team TI The Great Observatories Origins Deep Survey VLT/FORS2 spectroscopy in the GOODS-South Field SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmology : observations; cosmology : large-scale structure of Universe; galaxies : evolution ID HUBBLE-SPACE-TELESCOPE; LYMAN-BREAK GALAXIES; STAR-FORMATION RATE; HIGH-REDSHIFT; Z-APPROXIMATE-TO-6; EVOLUTION AB We present the first results of the ESO/ GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field South ( CDF- S). 399 spectra of 303 unique targets have been obtained in service mode with the FORS2 spectrograph at the ESO/ VLT, providing 234 redshift determinations ( the median of the redshift distribution is at 1.04). The typical redshift uncertainty is estimated to be sigma(z) similar or equal to 0.001. Galaxies have been color selected in a way that the resulting redshift distribution typically spans from z = 0.5 to 2. The reduced spectra and the derived redshifts are released to the community through the ESO web page http:// www. eso. org/ science/ goods/. Large scale structure is clearly detected at z similar or equal to 0.67, 0.73, 1.10 and 1.61. Three Lyman- break galaxies have also been included as targets and are confirmed to have redshifts z = 4.800, 4.882 and 5.828. In a few cases, we observe clear [ OII] 3727 rotation curves, even at the relatively low resolution ( R = 860) of the present observations. Assuming that the observed velocity structure is due to dynamically- relaxed rotation, this is an indication of large galactic masses ( few times 10(11) M.) at z similar to 1. C1 Univ Padua, Dipartimento Astron, I-35122 Padua, Italy. Osserv Astron Trieste, INAF, I-40131 Trieste, Italy. Natl Opt Astron Observ, Tucson, AZ 85726 USA. ST ECF, D-85748 Garching, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. European So Observ, D-85748 Garching, Germany. Univ Paris 11, F-91405 Orsay, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Groningen, Kapteyn Astron Inst, NL-9747 AD Groningen, Netherlands. RP Vanzella, E (reprint author), Univ Padua, Dipartimento Astron, Vicolo Osservatorio 2, I-35122 Padua, Italy. EM evanzell@eso.org RI Ettori, Stefano/N-5004-2015; OI Ettori, Stefano/0000-0003-4117-8617; Fosbury, Robert/0000-0001-9975-8003; Nonino, Mario/0000-0001-6342-9662; Cristiani, Stefano/0000-0002-2115-5234; Kuntschner, Harald/0000-0002-2768-1198; Moustakas, Leonidas/0000-0003-3030-2360 NR 29 TC 168 Z9 168 U1 0 U2 3 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2005 VL 434 IS 1 BP 53 EP 65 DI 10.1051/0004-6361:20041532 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912RN UT WOS:000228097300009 ER PT J AU Peeters, Z Botta, O Charnley, SB Kisiel, Z Kuan, YJ Ehrenfreund, P AF Peeters, Z Botta, O Charnley, SB Kisiel, Z Kuan, YJ Ehrenfreund, P TI Formation and photostability of N-heterocycles in space - I. The effect of nitrogen on the photostability of small aromatic molecules SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE astrobiology; methods : laboratory; stars : individual : CRL 618 ID DENSE INTERSTELLAR CLOUDS; AB-INITIO CALCULATIONS; CHEMICAL EVOLUTION; CARBONACEOUS CHONDRITES; PREBIOTIC SYNTHESIS; RADIATION-FIELD; CI CHONDRITES; PYRIMIDINES; BENZENE; SPECTRA AB Nitrogen-containing cyclic organic molecules (N-heterocycles) play important roles in terrestrial biology, for example as the nucleobases in genetic material. It has previously been shown that nucleobases are unlikely to form and survive in interstellar and circumstellar environments. Also, they were found to be unstable against ultraviolet (UV) radiation. However, nucleobases were detected in carbonaceous meteorites, suggesting their formation and survival is possible outside the Earth. In this study, the nucleobase precursor pyrimidine and the related N-heterocycles pyridine and s-triazine were tested for UV stability. All three N-heterocycles were found to photolyse rapidly and their stability decreased with an increasing number of nitrogen atoms in the ring. The laboratory results were extrapolated to astronomically relevant environments. In the diffuse interstellar medium ( ISM) these N-heterocycles in the gas phase would be destroyed in 10 - 100 years, while in the Solar System at 1 AU distance from the Sun their lifetime would not extend beyond several hours. The only environment where small N-heterocycles could survive, is in dense clouds. Pyridine and pyrimidine, but not s-triazine, could survive the average lifetime of such a cloud. The regions of circumstellar envelopes where dust attenuates the UV flux, may provide a source for the detection of N-heterocycles. We conclude that these results have important consequences for the detectability of N-heterocycles in astronomical environments. C1 Leiden Univ, Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. Int Space Sci Inst, CH-3012 Bern, Switzerland. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. Natl Taiwan Normal Univ, Dept Earth Sci, Taipei 116, Taiwan. Acad Sinica, Inst Astron & Astrophys, Taipei 106, Taiwan. RP Peeters, Z (reprint author), Leiden Univ, Leiden Inst Chem, Astrobiol Lab, POB 9502, NL-2300 RA Leiden, Netherlands. EM peeters@strw.leidenuniv.nl RI Charnley, Steven/C-9538-2012; Kisiel, Zbigniew/K-8798-2016 OI Kisiel, Zbigniew/0000-0002-2570-3154 NR 50 TC 50 Z9 50 U1 0 U2 14 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2005 VL 433 IS 2 BP 583 EP 590 DI 10.1051/0004-6361:20042443 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 909JS UT WOS:000227856800026 ER PT J AU Apai, D Toth, LV Henning, T Vavrek, R Kovacs, Z Lemke, D AF Apai, D Toth, LV Henning, T Vavrek, R Kovacs, Z Lemke, D TI HST/NICMOS observations of a proto-brown dwarf candidate SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE binaries : close; planetary systems : protoplanetary disks; stars : formation; stars : low-mass, brown dwarfs; stars : pre-main sequence ID SUBMILLIMETER CONTINUUM; EVOLUTIONARY MODELS; MASS; DISKS; SYSTEMS; OBJECTS; TAURUS; DUST; PROTOPLANETS; EXTINCTION AB We present deep HST/NICMOS observations peering through the outflow cavity of the protostellar candidate IRAS 04381+2540 in the Taurus Molecular Cloud-1. A young stellar object as central source, a jet and a very faint and close (0.6 '') companion are identified. The primary and the companion have similar colours, consistent with strong reddening. We argue that the companion is neither a shock-excited knot nor a background star. The colour/magnitude information predicts a substellar upper mass limit for the companion, but the final confirmation will require spectroscopic information. Because of its geometry, young age and its rare low-mass companion, this system is likely to provide a unique insight into the formation of brown dwarfs. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA Astrobiol Inst, Washington, DC USA. Eotvos Lorand Univ, Dept Astron, H-1117 Budapest, Hungary. Hungarian Acad Sci, Konkoly Observ Budapest, H-1525 Budapest, Hungary. ESTEC, Astrophys Missions Div, NL-2201 Norwijk, Netherlands. RP Apai, D (reprint author), Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. EM apai@as.arizona.edu RI Toth, L. Viktor/C-8667-2017 OI Toth, L. Viktor/0000-0002-5310-4212 NR 33 TC 9 Z9 9 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2005 VL 433 IS 2 BP L33 EP L36 DI 10.1051/0004-6361:200500098 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 909JS UT WOS:000227856800007 ER PT J AU Molkov, S Hurley, K Sunyaev, R Shtykovsky, P Revnivtsev, M Kouveliotou, C AF Molkov, S Hurley, K Sunyaev, R Shtykovsky, P Revnivtsev, M Kouveliotou, C TI The broad-band spectrum of the persistent emission from SGR 1806-20 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; pulsars : general; stars : individual : SGR 1806-20 ID SOFT GAMMA REPEATER; HIGH-ENERGY TRANSIENT; X-RAY PULSAR; SGR 1806-20; CYCLOTRON-RESONANCE; TIME HISTORIES; MAGNETIC-FIELD; COUNTERPART; DISCOVERY; CATALOG AB We present the results of an analysis of the quiescent X-ray emission from the Soft Gamma-Ray Repeater SGR 1806- 20, taken during an INTEGRAL ultra-deep survey of the Galactic center region in Aug.-Sep. 2003. The total effective exposure time spent on the source by the IBIS telescope during these observations was 1.6 million seconds. Combining the INTEGRAL results with results from the XMM-Newton observatory, we present the broad band (1-200 keV) spectrum of the quiescent emission from this source. This is the first spectrum of the persistent emission from an SGR in the broad energy range up to 200 keV. The spectrum of the source is very hard and has a power law shape (Gamma = 1.6 +/- 0.1) without any trace of a high energy cutoff up to similar to 160 keV. No strong cyclotron line was detected in the persistent spectrum. The luminosity of SGR 1806- 20 in this range ( 1-200 keV) was similar to 3.6 x 10(36) erg s(-1) for an assumed distance of 15 kpc. We show that weak undetected bursts should not contribute significantly to the quiescent emission. During our next observations in August 2004 the source went into an active phase and its average flux between powerful bursts was 2-3 times higher than in 2003. During Aug.-Sep. 2003, two other SGR candidates, SGR 1801-23 and SGR 1808-20, were in the field of view. Neither persistent hard X-ray emission nor bursts were detected from them. The upper limit on the persistent flux from each of them in the energy band 18-100 keV is about 4 x 10(-11) erg s(-1) cm(-2). C1 Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Max Planck Inst Astrophys, D-85740 Garching, Germany. NASA, MSFC, Natl Space Sci Technol Ctr, Huntsville, AL 35805 USA. RP Molkov, S (reprint author), Russian Acad Sci, Space Res Inst, Profsouznaya 84-32, Moscow 117997, Russia. EM molkov@hea.iki.rssi.ru NR 36 TC 43 Z9 43 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD APR PY 2005 VL 433 IS 2 BP L13 EP L16 DI 10.1051/0004-6361:200500087 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 909JS UT WOS:000227856800002 ER PT J AU Gorski, KM Hivon, E Banday, AJ Wandelt, BD Hansen, FK Reinecke, M Bartelmann, M AF Gorski, KM Hivon, E Banday, AJ Wandelt, BD Hansen, FK Reinecke, M Bartelmann, M TI HEALPix: A framework for high-resolution discretization and fast analysis of data distributed on the sphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : statistical ID ANISOTROPY; 2-SPHERE; MAPS AB HEALPix-the Hierarchical Equal Area isoLatitude Pixelization-is a versatile structure for the pixelization of data on the sphere. An associated library of computational algorithms and visualization software supports fast scientific applications executable directly on discretized spherical maps generated from very large volumes of astronomical data. Originally developed to address the data processing and analysis needs of the present generation of cosmic microwave background experiments (e.g., BOOMERANG, WMAP), HEALPix can be expanded to meet many of the profound challenges that will arise in confrontation with the observational output of future missions and experiments, including, e.g., Planck, Herschel, SAFIR, and the Beyond Einstein inflation probe. In this paper we consider the requirements and implementation constraints on a framework that simultaneously enables an efficient discretization with associated hierarchical indexation and fast analysis/synthesis of functions defined on the sphere. We demonstrate how these are explicitly satisfied by HEALPix. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. CALTECH, IPAC, Pasadena, CA 91125 USA. Max Planck Inst Astrophys, D-85741 Garching, Germany. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Heidelberg, ITA, D-69121 Heidelberg, Germany. RP Gorski, KM (reprint author), CALTECH, Jet Prop Lab, MS 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Bartelmann, Matthias/A-5336-2014; OI WANDELT, Benjamin/0000-0002-5854-8269; Hivon, Eric/0000-0003-1880-2733 NR 18 TC 1887 Z9 1904 U1 5 U2 39 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 759 EP 771 DI 10.1086/427976 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400001 ER PT J AU Lewis, KT Eracleous, M Gliozzi, M Sambruna, RM Mushotzky, RF AF Lewis, KT Eracleous, M Gliozzi, M Sambruna, RM Mushotzky, RF TI A simultaneous RXTE and XMM-Newton observation of the broad-line radio galaxy 3C 111 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : active; galaxies : individual (3C 111); galaxies : nuclei; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; X-RAY REFLECTION; K-ALPHA-EMISSION; SEYFERT-1 GALAXIES; COLD MATTER; COMPTON REFLECTION; ACCRETION DISK; MULTIWAVELENGTH OBSERVATIONS; MOLECULAR CLOUDS; TIMING-EXPLORER AB We present the results of simultaneous XMM-Newton and RXTE observations of the broad-line radio galaxy 3C 111. We find that the Compton reflection bump is extremely weak; however, broad residuals are clearly present in the spectrum near the Fe K alpha emission line region. When fitted with a Gaussian emission line, the feature has an equivalent width of 40-100 eV and FWHM of greater than 20,000 km s(-1); however, the exact properties of this weak line are highly dependent on the chosen continuum model. The width of the line suggests an origin in the inner accretion disk, which is, however, inconsistent with the lack of Compton reflection. We find that much of the broad residual emission can be attributed to continuum curvature. The data are consistent with a model in which the primary power-law continuum is reprocessed by an accretion disk that is truncated at small radii. Alternatively, the primary source could be partially covered by a dense absorber. The latter model is less attractive than the former because of the small inclination angle of the jet of 3C 111 to the line of sight. We consider it likely that the curved continuum of the partial covering model is fortuitously similar to the continuum shape of the reprocessing model. In both models, the fit is greatly improved by the addition of an unresolved Fe K alpha emission line, which could arise in either a Compton-thin obscuring torus or dense clouds lying along the line of sight. We also find that there are unacceptable residuals at low energies in the MOS data in particular, which were modeled as a Gaussian with an energy of similar to 1.5 keV; we attribute these residuals to calibration uncertainties of the MOS detectors. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20770 USA. RP Lewis, KT (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. EM lewis@astro.psu.edu; mce@astro.psu.edu; mario@physics.gmu.edu; rms@physics.gmu.edu; richard@milkyway.gsfc.nasa.gov NR 75 TC 25 Z9 25 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 816 EP 829 DI 10.1086/428380 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400005 ER PT J AU Nishikawa, KI Hardee, P Richardson, G Preece, R Sol, H Fishman, GJ AF Nishikawa, KI Hardee, P Richardson, G Preece, R Sol, H Fishman, GJ TI Particle acceleration and magnetic field generation in electron-positron relativistic shocks SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; elementary particles; ISM : jets and outflows; shock waves ID RAY BURST AFTERGLOW; WEIBEL INSTABILITY; PLASMA; JETS; EMISSION; WAVES; SIMULATIONS; MORPHOLOGY; RADIATION AB Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel, and other two-stream instabilities) created in collisionless shocks are responsible for particle ( electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle ( REMP) code, we have investigated particle acceleration associated with a relativistic electron-positron jet front propagating into an ambient electron-positron plasma with and without initial magnetic fields. We find small differences in the results for no ambient and modest ambient magnetic fields. New simulations show that the Weibel instability created in the collisionless shock front accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction. Furthermore, the nonlinear fluctuation amplitudes of densities, currents, and electric and magnetic fields in the electron-positron shock are larger than those found in the electron-ion shock studied in a previous paper at a comparable simulation time. This comes from the fact that both electrons and positrons contribute to generation of the Weibel instability. In addition, we have performed simulations with different electron skin depths. We find that growth times scale inversely with the plasma frequency, and the sizes of structures created by the Weibel instability scale proportionally to the electron skin depth. This is the expected result and indicates that the simulations have sufficient grid resolution. While some Fermi acceleration may occur at the jet front, the majority of electron and positron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying nonuniform, small-scale magnetic fields, which contribute to the electron's ( positron's) transverse deflection behind the jet head. This smallscale magnetic field structure is appropriate to the generation of "jitter'' radiation from deflected electrons ( positrons) as opposed to synchrotron radiation. The jitter radiation has different properties than synchrotron radiation calculated assuming a uniform magnetic field. The jitter radiation resulting from small-scale magnetic field structures may be important for understanding the complex time structure and spectral evolution observed in gamma-ray bursts or other astrophysical sources containing relativistic jets and relativistic collisionless shocks. C1 NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. Univ Alabama, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Observ Paris, LUTH, F-92195 Meudon, France. RP Nishikawa, KI (reprint author), NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. EM ken-ichi.nishikawa@nsstc.nasa.gov; hardee@athena.astr.ua.edu; georgia.richardson@nsfc.nasa.gov OI Preece, Robert/0000-0003-1626-7335 NR 32 TC 110 Z9 114 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 927 EP 937 DI 10.1086/428394 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400014 ER PT J AU Levan, A Patel, S Kouveliotou, C Fruchter, A Rhoads, J Rol, E Ramirez-Ruiz, E Gorosabel, J Hjorth, J Wijers, R Wood-Vasey, WM Bersier, D Castro-Tirado, A Fynbo, J Jensen, B Pian, E Tanvir, N Thorsett, S Woosley, S AF Levan, A Patel, S Kouveliotou, C Fruchter, A Rhoads, J Rol, E Ramirez-Ruiz, E Gorosabel, J Hjorth, J Wijers, R Wood-Vasey, WM Bersier, D Castro-Tirado, A Fynbo, J Jensen, B Pian, E Tanvir, N Thorsett, S Woosley, S TI A deep search with the Hubble Space Telescope for late-time supernova signatures in the hosts of XRF 011030 and XRF 020427 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID GAMMA-RAY BURSTS; OPTICAL AFTERGLOW; ORPHAN AFTERGLOWS; LOW-LUMINOSITY; SN 2003LW; GRB-031203; DISCOVERY; GALAXIES; EMISSION; FLASH AB X-ray flashes (XRFs) are, like gamma-ray bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower than those for GRBs, such that they are visible from a reduced range of distances when compared with GRBs. Here we present the results of two-epoch Hubble Space Telescope imaging of two XRFs. These images, taken approximately 45 and 200 days postburst, reveal no evidence of an associated supernova in either case. Supernovae such as SN 1998bw would have been visible out to z similar to 1.5 in each case, while fainter supernovae such as SN 2002ap would have been visible to z similar to 1. If the XRFs lie at such large distances, their energies would not fit the observed correlation between the GRB peak energy and isotropic energy release (E(p) proportional to E(iso)(1/2)), in which soft bursts are less energetic. We conclude that, should these XRFs reside at low redshifts (z < 0.6), either their line of sight is heavily extinguished, they are associated with extremely faint supernovae, or, unlike GRBs, these XRFs do not have temporally coincident supernovae. C1 Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Space Res Assoc, Natl Space Sci Technol Ctr, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci Technol Ctr, Huntsville, AL 35805 USA. Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Osserv Astron Trieste, INAF, I-34131 Trieste, Italy. Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. RP Levan, A (reprint author), Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. RI Hjorth, Jens/M-5787-2014; Jensen, Brian Lindgren/E-1275-2015; OI Hjorth, Jens/0000-0002-4571-2306; Jensen, Brian Lindgren/0000-0002-0906-9771; Thorsett, Stephen/0000-0002-2025-9613; Wijers, Ralph/0000-0002-3101-1808; Castro-Tirado, A. J./0000-0003-2999-3563; Pian, Elena/0000-0001-8646-4858 NR 87 TC 16 Z9 16 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 977 EP 985 DI 10.1086/426938 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400019 ER PT J AU Wilson, CA Weisskopf, MC Finger, MH Coe, MJ Greiner, J Reig, P Papamastorakis, G AF Wilson, CA Weisskopf, MC Finger, MH Coe, MJ Greiner, J Reig, P Papamastorakis, G TI Discovery of a Be/X-ray binary consistent with the position of GRO J2058+42 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; pulsars : individual (GRO J2058+42); X-rays : binaries ID CROSS-SECTIONS; STARS; TRANSIENT; EMISSION; PULSAR; GALAXY; RXTE; ABUNDANCES; OUTBURST; SYSTEM AB GRO J2058+42 is a 195 s transient X-ray pulsar discovered in 1995 with BATSE. In 1996, RXTE located GRO J2058+42 to a 90% confidence error circle with a 40 radius. On 2004 February 20, the region including the error circle was observed with Chandra ACIS-I. No X-ray sources were detected within the error circle; however, two faint sources were detected in the ACIS-I field of view. We obtained optical observations of the brightest object, CXOU J205847.5+414637, which had about 64 X-ray counts and was just 0 '.3 outside the error circle. The optical spectrum contains a strong H alpha line and corresponds to an infrared object in the Two Micron All Sky Survey catalog, indicating a Be/X-ray binary system. Pulsations were not detected in the Chandra observations, but similar flux variations and distance estimates suggest that CXOU J205847.5+414637 and GRO J2058+42 are the same object. We present results from the Chandra observation, optical observations, new and previously unreported RXTE observations, and a reanalysis of a ROSAT observation. C1 Natl Space Sci & Technol Ctr, Space Sci Branch XD 12, Huntsville, AL 35805 USA. Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Univ Crete, Dept Phys, Iraklion 71003, Greece. Fdn Res & Technol, IESL, Iraklion 71110, Greece. RP Wilson, CA (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM colleen.wilson@nasa.gov RI Papamastorakis, Ioannis/G-7324-2011; Reig, Pablo/A-1198-2014 OI Reig, Pablo/0000-0002-6446-3050 NR 53 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1024 EP 1032 DI 10.1086/428381 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400023 ER PT J AU Deming, D Brown, TM Charbonneau, D Harrington, J Richardson, LJ AF Deming, D Brown, TM Charbonneau, D Harrington, J Richardson, LJ TI A new search for carbon monoxide absorption in the transmission spectrum of the extrasolar planet HD 209458b SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : eclipsing; planetary systems; stars : individual (HD 209458); techniques : spectroscopic ID GIANT PLANET; INFRARED OBSERVATIONS; TRANSITING PLANET; SECONDARY ECLIPSE; ATMOSPHERE; SPECTROSCOPY; TELESCOPE; STAR; CO; TEMPERATURES AB We have revisited the search for carbon monoxide absorption features in transmission during the transit of the extrasolar planet HD 209458b. In 2002 August-September we acquired a total of 1077 high-resolution spectra (lambda/delta lambda similar to 25,000) in the K-band (2 mu m) wavelength region using NIRSPEC on the Keck II telescope during three transits. These data are more numerous and of better quality than the data analyzed in an initial search by Brown et al. Our analysis achieves a sensitivity sufficient to test the degree of CO absorption in the first-overtone bands during transit on the basis of plausible models of the planetary atmosphere. We analyze our observations by comparison with theoretical tangent geometry absorption spectra, computed by adding height-invariant ad hoc temperature perturbations to the model atmosphere of Sudarsky et al. and by treating cloud height as an adjustable parameter. We do not detect CO absorption. The strong 2-0 R-branch lines between 4320 and 4330 cm(-1) have depths during transit less than 1.6 parts in 10(4) in units of the stellar continuum (3 sigma limit) at a spectral resolving power of 25,000. Our analysis indicates a weakening similar to that found in the case of sodium, suggesting that a general masking mechanism is at work in the planetary atmosphere. Under the interpretation that this masking is provided by high clouds, our analysis defines the maximum cloud-top pressure (i.e., minimum height) as a function of the model atmospheric temperature. For the relatively hot model used by Charbonneau et al. to interpret their sodium detection, our CO limit requires cloud tops at or above 3.3 mbar, and these clouds must be opaque at a wavelength of 2 mu m. High clouds comprised of submicron-sized particles are already present in some models but may not provide sufficient opacity to account for our CO result. Cooler model atmospheres, having smaller atmospheric scale heights and lower CO mixing ratios, may alleviate this problem to some extent. However, even models 500 K cooler than the Sudarsky et al. model require clouds above the 100 mbar level to be consistent with our observations. Our null result therefore requires clouds to exist at an observable level in the atmosphere of HD 209458b, unless this planet is dramatically colder than current belief. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. NASA, Natl Res Council, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Deming, D (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Code 693, Greenbelt, MD 20771 USA. EM ddeming@pop600.gsfc.nasa.gov; timbrown@hao.ucar.edu; dcharbonneau@cfa.harvard.edu; jh@oobleck.astro.cornell.edu; lee.j.richardson.1@gsfc.nasa.gov RI Harrington, Joseph/E-6250-2011; OI Charbonneau, David/0000-0002-9003-484X; Harrington, Joseph/0000-0002-8955-8531 NR 47 TC 56 Z9 57 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1149 EP 1159 DI 10.1086/428376 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400034 ER PT J AU Beichman, CA Bryden, G Rieke, GH Stansberry, JA Trilling, DE Stapelfeldt, KR Werner, MW Engelbracht, CW Blaylock, M Gordon, KD Chen, CH Su, KYL Hines, DC AF Beichman, CA Bryden, G Rieke, GH Stansberry, JA Trilling, DE Stapelfeldt, KR Werner, MW Engelbracht, CW Blaylock, M Gordon, KD Chen, CH Su, KYL Hines, DC TI Planets and infrared excesses: Preliminary results from a Spitzer MIPS survey of solar-type stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; Kuiper Belt; planetary systems : formation; planetary systems : protoplanetary disks ID MAIN-SEQUENCE STARS; VEGA PHENOMENON; SPACE-TELESCOPE; CORONAGRAPHIC OBSERVATIONS; SUBMILLIMETER OBSERVATIONS; EPSILON-ERIDANI; AGE-DEPENDENCE; GIANT PLANETS; NEARBY STARS; DUSTY DEBRIS AB As part of a large Spitzer MIPS Guaranteed Time Observation program, we have searched for infrared excesses due to debris disks toward 26 FGK field stars known from radial velocity (RV) studies to have one or more planets. While none of these stars show excesses at 24 mu m, we have detected 70 mu m excesses around six stars at the 3 sigma confidence level. The excesses are produced by cool material (<100 K) located beyond 10 AU, well outside the "habitable zones" of these systems and consistent with the presence of Kuiper Belt analogs with similar to 100 times more emitting surface area than in our own planetary system. These planet-bearing stars are, by selection for RV studies, typically older than 1 Gyr, and the stars identified here with excesses have a median age of 4 Gyr. We find a preliminary correlation of both the frequency and the magnitude of dust emission with the presence of known planets. These are the first stars outside the solar system identified as having both well-confirmed planetary systems and well-confirmed IR excesses. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Beichman, CA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Stapelfeldt, Karl/D-2721-2012; OI Su, Kate/0000-0002-3532-5580 NR 61 TC 101 Z9 102 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1160 EP 1170 DI 10.1086/428115 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400035 ER PT J AU Roberge, A Weinberger, AJ Malumuth, EM AF Roberge, A Weinberger, AJ Malumuth, EM TI Spatially resolved spectroscopy and coronagraphic imaging of the TW Hydrae circumstellar disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems : protoplanetary disks; stars : individual (TW Hydrae); stars : pre-main-sequence ID BETA-PICTORIS; RADIATION; VARIABILITY; IMAGES AB We present the first spatially resolved spectrum of scattered light from the TW Hydrae protoplanetary disk. This nearly face-on disk is optically thick, surrounding a classical T Tauri star in the nearby 10 Myr old TW Hya association. The spectrum was taken with the Hubble Space Telescope (HST) STIS CCD, providing resolution R similar to 360 over the wavelength range 5250-10300 angstrom. Spatially resolved spectroscopy of circumstellar disks is difficult because of the high contrast ratio between the bright star and faint disk. Our novel observations provide optical spectra of scattered light from the disk between 40 and 155 AU from the star. The scattered light has the same color as the star (gray scattering) at all radii except the innermost region. This likely indicates that the scattering dust grains are larger than about 1 mu m all the way out to large radii. From the spectroscopic data, we also obtained radial profiles of the integrated disk brightness at two position angles, over almost the same region as previously observed in HST WFPC2 and NICMOS coronagraphic images (35 to 173 AU from the star). The profiles have the same shape as the earlier ones, but show a small azimuthal asymmetry in the disk not previously noted. Our STIS broadband coronagraphic images of TW Hya confirm the reality of this asymmetry, and show that the disk surface brightness inside 140 AU has a sinusoidal dependence on azimuthal angle. The maximum brightness occurs at a position angle of 233.degrees 6 +/- 5.degrees 7 east of north. This might be caused by the combination of forward scattering and an increase in inclination in the inner region of the disk, suggesting that the TW Hya disk has a warp like that seen in the beta Pictoris debris disk. C1 Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Roberge, A (reprint author), Carnegie Inst Washington, Dept Terr Magnetism, 5241 Broad Branch Rd NW, Washington, DC 20015 USA. EM akir@dtm.ciw.edu; alycia@dtm.ciw.edu; eliot@barada.gsfc.nasa.gov RI Roberge, Aki/D-2782-2012; OI Roberge, Aki/0000-0002-2989-3725; Weinberger, Alycia/0000-0001-6654-7859 NR 19 TC 27 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1171 EP 1181 DI 10.1086/427974 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400036 ER PT J AU Brosius, JW AF Brosius, JW TI Mass flows in a disappearing sunspot plume SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona; Sun : transition region; Sun : UV radiation; sunspots ID CORONAL DIAGNOSTIC SPECTROMETER; EXTREME ULTRAVIOLET-SPECTRUM; TRANSITION-REGION BLINKERS; SOFT-X-RAY; QUIET-SUN; ATOMIC DATABASE; ACTIVE REGIONS; EMISSION-LINES; SOLAR; SOHO AB We observed a large sunspot in NOAA Active Region 9535 on 2001 July 12, 15, 17, and 19 with three instruments (CDS, EIT, and MDI) on board SOHO. EUV emission lines of O IV (formed at logarithmic temperature of 5.2), O V (5.4), Ne IV (5.2), Ne V (5.5), Ne VI (5.6), Ne VII (5.7), and Ca X (5.9) revealed a large bright plume within the sunspot penumbra on July 12 and 15, a smaller, dimmer plume on July 17, and no plume on July 19. Downflows of 25 km s(-1) or more were measured within the sunspot plume on July 12 and 15. By July 17 the downflow area had shrunk in size, the downflows had diminished in magnitude, and upflows were measured in the umbra and parts of the penumbra outside the plume. By July 19 downflows were no longer observed, but had been replaced entirely with upflows of 15-25 km s(-1) in the umbra and portions of the penumbra. This is the first time that the disappearance of a sunspot plume has been observed to occur simultaneously with a dramatic change in flow velocity pattern in the sunspot plume and umbra. On July 12 upflows northeast of the sunspot were observed along with the downflows in the plume. Electron density measurements based on intensity ratios of the O IV lines at 625.8 and 554.5 angstrom indicate a significantly greater value in the upflow zone than in the plume, consistent with siphon flow as the driver of the observed velocities; however, the line at 625.8 angstrom is very weak and blended in the red wing of the Mg X line at 624.9 angstrom, so derived densities are highly uncertain. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Brosius, JW (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. NR 31 TC 12 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1216 EP 1224 DI 10.1086/428345 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400041 ER PT J AU Krot, AN Hutcheon, ID Yurimoto, H Cuzzi, JN McKeegan, KD Scott, ERD Libourel, G Chaussidon, M Aleon, J Petaev, MI AF Krot, AN Hutcheon, ID Yurimoto, H Cuzzi, JN McKeegan, KD Scott, ERD Libourel, G Chaussidon, M Aleon, J Petaev, MI TI Evolution of oxygen isotopic composition in the inner solar nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE meteors, meteoroids; nuclear reactions, nucleosynthesis, abundances; planetary systems : formation; solar system : formation ID ALUMINUM-RICH INCLUSIONS; CARBONACEOUS CHONDRITE ACFER-094; SHORT-LIVED NUCLIDES; REFRACTORY INCLUSIONS; FERROMAGNESIAN CHONDRULES; CONTEMPORANEOUS FORMATION; SYSTEM; ALLENDE; ORIGIN; AL-26 AB Changes in the chemical and isotopic composition of the solar nebula with time are reflected in the properties of different constituents that are preserved in chondritic meteorites. CR-group carbonaceous chondrites are among the most primitive of all chondrite types and must have preserved solar nebula records largely unchanged. We have analyzed the oxygen and magnesium isotopes in a range of the CR constituents of different formation temperatures and ages, including refractory inclusions and chondrules of various types. The results provide new constraints on the time variation of the oxygen isotopic composition of the inner (<5 AU) solar nebula - the region where refractory inclusions and chondrules most likely formed. A chronology based on the decay of short-lived Al-26 (t(1/2) similar to 0.73 Myr) indicates that the inner solar nebula gas was O-16-rich when refractory inclusions formed, but less than 0.8 Myr later, gas in the inner solar nebula became O-16-poor, and this state persisted at least until CR chondrules formed similar to 1-2 Myr later. We suggest that the inner solar nebula became O-16-poor because meter-sized icy bodies, which were enriched in O-17 and O-18 as a result of isotopic self-shielding during the ultraviolet photo-dissociation of CO in the protosolar molecular cloud or protoplanetary disk, agglomerated outside the snow line, drifted rapidly toward the Sun, and evaporated at the snow line. This led to significant enrichment in O-16-depleted water, which then spread through the inner solar system. Astronomical studies of the spatial and temporal variations of water abundance in protoplanetary disks may clarify these processes. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. Lawrence Livermore Natl Lab, Livermore, CA 94451 USA. Tokyo Inst Technol, Dept Earth & Planetary Sci, Meguro Ku, Tokyo 1528551, Japan. NASA, Space Sci & Astrobiol Div, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Ctr Rech Petrog & Geochim, CNRS, UPR 2300, F-54501 Vandoeuvre Les Nancy, France. Inst Natl Polytech Lorraine, Ecole Natl Super Geol, F-54501 Vandoeuvre Les Nancy, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. RP Krot, AN (reprint author), Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Hawaii Inst Geophys & Planetol, 1680 East West Rd, Honolulu, HI 96822 USA. EM sasha@higp.hawaii.edu RI McKeegan, Kevin/A-4107-2008; UCLA, SIMS/A-1459-2011; Chaussidon, Marc/E-7067-2017 OI McKeegan, Kevin/0000-0002-1827-729X; NR 90 TC 62 Z9 62 U1 4 U2 10 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1333 EP 1342 DI 10.1086/428382 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400050 ER PT J AU Bussmann, RS Holzapfel, WL Kuo, CL AF Bussmann, RS Holzapfel, WL Kuo, CL TI Millimeter wavelength brightness fluctuations of the atmosphere above the South Pole SO ASTROPHYSICAL JOURNAL LA English DT Article DE atmospheric effects; cosmic microwave background; site testing ID ANTARCTIC PLATEAU; POWER SPECTRUM; TURBULENCE; ASTRONOMY; RECEIVER; ACBAR AB We report measurements of the millimeter wavelength brightness fluctuations produced by the atmosphere above the South Pole made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR). The data span the 2002 austral winter during which ACBAR was mounted on the Viper Telescope at the South Pole. We recover the atmospheric signal in the presence of instrument noise by calculating the correlation between signals from distinct elements of the ACBAR bolometer array. With this method, it is possible to measure atmospheric brightness fluctuations with a high signal-to-noise ratio even under the most stable atmospheric conditions. The observed atmospheric signal is characterized by the parameters of the Kolmogorov-Taylor (KT) model, which are the amplitude and power-law exponent describing the atmospheric power spectrum and the two components of the wind angular velocity at the time of the observation. The KT model is typically a good description of the observed fluctuations, and fits to the data produce values of the Kolmogorov exponent that are consistent with theoretical expectations. By combining the wind angular velocity results with measurements of the wind linear velocity, we find that the altitude of the observed atmospheric fluctuations is consistent with the distribution of water vapor determined from radiosonde data. For data corresponding to frequency passbands centered on 150, 219, and 274 GHz, we obtain median fluctuation power amplitudes of (10, 38, 74) mK(2) rad(-5/3) in Rayleigh-Jeans temperature units. Comparing with previous work, we find that these median amplitudes are approximately an order of magnitude smaller than those found at the South Pole during the austral summer and at least 30 times lower than found at the ALMA site in the Atacama desert. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bussmann, RS (reprint author), Univ Calif Berkeley, Dept Phys, 361 LeConte Hall, Berkeley, CA 94720 USA. EM rsbussmann@as.arizona.edu; swlh@cosmology.berkeley.edu; clkuo@astro.caltech.edu RI Holzapfel, William/I-4836-2015 NR 14 TC 24 Z9 24 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP 1343 EP 1355 DI 10.1086/427935 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QD UT WOS:000228093400051 ER PT J AU Buratti, BJ Cruikshank, DP Brown, RH Clark, RN Bauer, JM Jaumann, R McCord, TB Simonelli, DP Hibbitts, CA Hansen, GB Owen, TC Baines, KH Bellucci, G Bibring, JP Capaccioni, F Cerroni, P Coradini, A Drossart, P Formisano, V Langevin, Y Matson, DL Mennella, V Nelson, RM Nicholson, PD Sicardy, B Sotin, C Roush, TL Soderlund, K Muradyan, A AF Buratti, BJ Cruikshank, DP Brown, RH Clark, RN Bauer, JM Jaumann, R McCord, TB Simonelli, DP Hibbitts, CA Hansen, GB Owen, TC Baines, KH Bellucci, G Bibring, JP Capaccioni, F Cerroni, P Coradini, A Drossart, P Formisano, V Langevin, Y Matson, DL Mennella, V Nelson, RM Nicholson, PD Sicardy, B Sotin, C Roush, TL Soderlund, K Muradyan, A TI Cassini visual and infrared mapping spectrometer observations of Iapetus: Detection of CO2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE planets and satellites : individual (Iapetus); solar system : formation ID DARK SIDE; H2O ICE; SURFACES; SPECTRA; LAPETUS; ORIGIN AB The Visual and Infrared Mapping Spectrometer (VIMS) instrument aboard the Cassini spacecraft obtained its first spectral map of the satellite Iapetus in which new absorption bands are seen in the spectra of both the low-albedo hemisphere and the H2O ice-rich hemisphere. Carbon dioxide is identified in the low-albedo material, probably as a photochemically produced molecule that is trapped in H2O ice or in some mineral or complex organic solid. Other absorption bands are unidentified. The spectrum of the low-albedo hemisphere is satisfactorily modeled with a combination of organic tholin, poly-HCN, and small amounts of H2O ice and Fe2O3. The high-albedo hemisphere is modeled with H2O ice slightly darkened with tholin. The detection of CO2 in the low-albedo material on the leading hemisphere supports the contention that it is carbon-bearing material from an external source that has been swept up by the satellite's orbital motion. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. US Geol Survey, Fed Ctr, Lakewood, CO 80225 USA. DLR, Inst Planetary Explorat, D-12484 Berlin, Germany. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Inst Geophys & Planetol, Planetary Geosci Div, Honolulu, HI 96822 USA. Planetary Sci Inst, Pasadena, CA 91101 USA. CNR, Inst Fis Spazio Interplanetario, I-00133 Rome, Italy. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Observ Paris, F-92195 Meudon, France. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Nantes, CNRS, UMR 6112, Lab Planetol & Geodynam, F-44322 Nantes, France. RP Buratti, BJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-501, Pasadena, CA 91109 USA. RI Hibbitts, Charles/B-7787-2016; OI Hibbitts, Charles/0000-0001-9089-4391; Cerroni, Priscilla/0000-0003-0239-2741; Bellucci, Giancarlo/0000-0003-0867-8679; Capaccioni, Fabrizio/0000-0003-1631-4314 NR 21 TC 66 Z9 66 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP L149 EP L152 DI 10.1086/429800 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QH UT WOS:000228093800019 ER PT J AU Burrows, DN Hill, JE Chincarini, G Tagliaferri, G Campana, S Moretti, A Romano, P Malesani, D Racusin, JL Kobayashi, S Zhang, B Meszaros, P O'Brien, PT Willingale, R Osborne, JP Cusumano, G Giommi, P Angelini, L Abbey, AF Antonelli, LA Beardmore, AP Capalbi, M Covino, S D'Avanzo, P Goad, MR Kennea, JA Morris, DC Pagani, C Page, KL Stella, L Nousek, JA Wells, AA Gehrels, N AF Burrows, DN Hill, JE Chincarini, G Tagliaferri, G Campana, S Moretti, A Romano, P Malesani, D Racusin, JL Kobayashi, S Zhang, B Meszaros, P O'Brien, PT Willingale, R Osborne, JP Cusumano, G Giommi, P Angelini, L Abbey, AF Antonelli, LA Beardmore, AP Capalbi, M Covino, S D'Avanzo, P Goad, MR Kennea, JA Morris, DC Pagani, C Page, KL Stella, L Nousek, JA Wells, AA Gehrels, N TI Swift X-Ray Telescope and very large telescope observations of the afterglow of GRB 041223 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID CRAB-NEBULA; BURSTS; JETS; EMISSION; SPECTRUM AB GRB 041223 was the first gamma-ray burst detected by the Swift X-Ray Telescope (XRT), beginning 4.6 hr after the burst. The X-ray detection triggered a VLT observation of the optical/near-infrared (NIR) counterpart, located about 1.'' 1 from the XRT position. The X-ray counterpart faded rapidly, with a power-law index of -1.72 +/- 0.20, with an average unabsorbed X-ray flux of 6.5 x 10(-12) ergs cm(- 2) s(-1) in the 0.5-10 keV band for a power-law spectrum of photon index 2.02 +/- 0.13 with Galactic absorption. The NIR counterpart was observed at three epochs between 16 and 87 hr after the burst and faded with a power-law index of -1.14 +/- 0.8 with a reddening-corrected spectral energy distribution power-law slope of -0.40 +/- 0.08. We find that the X-ray and NIR data are consistent with a two-component jet in a wind medium. C1 Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. INAF, Osservatorio Astron Brera, I-23807 Merate, Italy. Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, Italy. SISSA, ISAS, Int Sch Adv Studies, I-34014 Trieste, Italy. Penn State Univ, Ctr Gravitat Wave Phys, University Pk, PA 16802 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. INAF, Ist Astrofis Spaziale & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. ASI Sci Data Ctr, I-00044 Frascati, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Leicester, Space Res Ctr, Leicester LE1 7RH, Leics, England. INAF, Osservatorio Astron Roma, I-00040 Monte Porzio Catone, Italy. RP Burrows, DN (reprint author), Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA. EM burrows@astro.psu.edu RI Gehrels, Neil/D-2971-2012; Racusin, Judith/D-2935-2012; OI Romano, Patrizia/0000-0003-0258-7469; Covino, Stefano/0000-0001-9078-5507; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 24 TC 8 Z9 8 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP L85 EP L88 DI 10.1086/429666 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QH UT WOS:000228093800003 ER PT J AU Thomas, BC Jackman, CH Melott, AL Laird, CM Stolarski, RS Gehrels, N Cannizzo, JK Hogan, DP AF Thomas, BC Jackman, CH Melott, AL Laird, CM Stolarski, RS Gehrels, N Cannizzo, JK Hogan, DP TI Terrestrial ozone depletion due to a milky way gamma-ray burst SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; gamma rays : bursts ID 2-DIMENSIONAL MODEL; NEARBY SUPERNOVAE; COSMIC-RAYS; EXTINCTION; RADIATION; TRANSPORT; EVENTS AB Based on cosmological rates, it is probable that at least once in the last gigayear the Earth has been irradiated by a gamma-ray burst (GRB) in our Galaxy from within 2 kpc. We have performed the first detailed computation of the effects on the Earth's atmosphere of one such impulsive event: A 10 s 100 kJ m(-2) burst penetrates to the stratosphere causing globally averaged ozone depletion of 35%, with depletion reaching 55% at some latitudes. Significant depletion persists for over 5 years after the burst. A 50% decrease in ozone column density leads to approximately 3 times the normal UVB (280-315 nm; a wavelength band that ozone significantly absorbs and that living organisms are sensitive to) flux, and widespread extinctions are likely, based on extrapolation from sensitivity of modern organisms. Additional effects include a shot of nitrate fertilizer and NO2 opacity in the visible, providing a cooling perturbation to the climate over a similar timescale. These results lend support to the hypothesis that a GRB may have initiated the late Ordovician mass extinction (Melott et al.). C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Lab Astroparticle Phys, Greenbelt, MD 20771 USA. Haskell Indian Nations Univ, Lawrence, KS 66046 USA. RP Thomas, BC (reprint author), Univ Kansas, Dept Phys & Astron, 1251 Wescow Hall Dr,1082 Malott Hall, Lawrence, KS 66045 USA. EM bthomas@ku.edu; jackman@assess.gsfc.nasa.gov; melott@ku.edu; claird@ku.edu; stolar@polska.gsfc.nasa.gov; gehrels@milkyway.gsfc.nasa.gov; cannizzo@milkyway.gsfc.nasa.gov RI Gehrels, Neil/D-2971-2012; Stolarski, Richard/B-8499-2013; Jackman, Charles/D-4699-2012; OI Stolarski, Richard/0000-0001-8722-4012; Thomas, Brian/0000-0001-9091-0830 NR 25 TC 29 Z9 30 U1 1 U2 14 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 2005 VL 622 IS 2 BP L153 EP L156 DI 10.1086/429799 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 912QH UT WOS:000228093800020 ER PT J AU Thompson, DJ Bertsch, DL O'Neal, RH AF Thompson, DJ Bertsch, DL O'Neal, RH TI The highest-energy photons seen by the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE gamma rays : observations ID EMISSION; CALIBRATION AB During its 9 year lifetime, the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) detected 1506 cosmic photons with measured energy E > 10 GeV. Of this number, 187 are found within a 1 degrees of sources that are listed in the Third EGRET Catalog and were included in determining the detection likelihood, flux, and spectra of those sources. In particular, five detected EGRET pulsars are found to have events above 10 GeV, and together they account for 37 events. A pulsar not included in the Third EGRET Catalog has two events, both with the same phase and in one peak of the lower energy gamma-ray light curve. Most of the remaining 1319 events appear to be diffuse Galactic and extragalactic radiation based on the similarity of their spatial and energy distributions with the diffuse model and in the E > 100 MeV emission. No significant time clustering that would suggest a burst was detected. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Florida A&M Univ, Dept Phys, Tallahassee, FL 32307 USA. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM djt@egret.gsfc.nasa.gov; dlb@egret.fsfc.nasa.gov; oneal@milkyway.gsfc.nasa.gov RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 19 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD APR PY 2005 VL 157 IS 2 BP 324 EP 334 DI 10.1086/427981 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 907TG UT WOS:000227740300007 ER PT J AU Perrone, MR Santese, M Tafuro, AM Holben, B Smirnov, A AF Perrone, MR Santese, M Tafuro, AM Holben, B Smirnov, A TI Aerosol load characterization over South-East Italy for one year of AERONET sun-photometer measurements SO ATMOSPHERIC RESEARCH LA English DT Article DE sun photometer; aerosols; aerosol optical and microphysical properties ID SKY RADIANCE MEASUREMENTS; OPTICAL-PROPERTIES; AFRICAN DUST; MINERALOGICAL COMPOSITION; NORTHERN GREECE; RAMAN LIDAR; DEPTH; THESSALONIKI; DATABASE; NETWORK AB Daily averaged retrievals of AERONET sun photometer measurements from March 2003 to March 2004 are used to provide preliminary results on the characterization of aerosol properties and changes over south-east Italy (40 degrees 20' N, 18 degrees 16' E). It is shown that aerosol optical and microphysical properties and the dominating aerosol types depend on seasons. Aerosol -parameter frequency distributions reveal the presence of individual modes that lead to the assumption that moderately absorbing urban-industrial and marine-polluted aerosols dominate in spring-summer and autumn-winter, respectively. It is shown that aerosol optical depths (AODs), single scattering albedos (SSAs), and Angstrom coefficients (angstrom) of urban-industrial (spring-summer) aerosols are characterized by lognormal distributions with peak values of 0.20 +/- 0.03, 0.94 +/- 0.01, and 1.58 +/- 0.03, respectively. On the contrary AOD, SSA and angstrom values of inaritime-polluted (autumn-winter) aerosols are characterized by lognormal distributions with peak values of 0.049 +/- 0.008, 0.974 +/- 0.003, and 0.7 +/- 0.1, respectively. It is also shown that the frequency distribution of real it and imaginary k refractive indices permits inference of the dominant aerosol constituents: sea-salt, water soluble, soot, and mineral particles. Finally, it is shown that dust outbreaks do not significantly affect the seasonal evolution of aerosol parameters, and that sunphotometry retrievals along dust events are in satisfactory accord with experimental findings indicating that moderately-absorbing (0.005 <= k <= 0.05) dust particles with a high content of illite are mainly advected over the Mediterranean basin during Sahara dust storms. (c) 2005 Elsevier B.V. All rights reserved. C1 Univ Lecce, Dept Phys, I-73100 Lecce, Italy. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Perrone, MR (reprint author), Univ Lecce, Dept Phys, I-73100 Lecce, Italy. EM perrone@le.infn.it RI Smirnov, Alexander/C-2121-2009 OI Smirnov, Alexander/0000-0002-8208-1304 NR 36 TC 37 Z9 38 U1 1 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD APR PY 2005 VL 75 IS 1-2 BP 111 EP 133 DI 10.1016/j.atmosres.2004.12.003 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 915XF UT WOS:000228344000006 ER PT J AU Rafiq, A Broderick, TJ Williams, DR Doarn, CR Jones, JA Merrell, RC AF Rafiq, A Broderick, TJ Williams, DR Doarn, CR Jones, JA Merrell, RC TI Assessment of simulated surgical skills in parabolic microgravity SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE laparoscopic surgical simulation; medical care; training; surgery in space; laparoscopic surgery ID VIRTUAL-REALITY; PERFORMANCE; SPACE AB Background. During spaceflight crew health is paramount in the success of flight missions. The delivery of healthcare during flight requires crew readiness for medical and surgical response. Methods: There were 20 participants who were evaluated for accurate performance of 4 basic laparoscopic surgical skills (clip applying, cutting, grasping, and suturing) during parabolic weightlessness using an inanimate workstation aboard the NASA KC-135 aircraft. Results: Data indicate that motor skill performance decreased within the parabolic microgravity flight environment. Performance in parabolic microgravity flight included futile effort with an increase in number of tasks attempted and a decrease in tasks completed successfully. Conclusions: There is a decreased frequency of accurate task completion in parabolic microgravity flight, but it is not an obstacle to implementation of effective training for providing in-flight medical care. The data reveal that individuals perform basic laparoscopic surgical simulation with greater effort in microgravity following simulation training. C1 Virginia Commonwealth Univ, Med Informat & Technol Appl Consortium, Dept Surg, Richmond, VA 23298 USA. Univ Cincinnati, Ctr Surg Innovat, Cincinnati, OH USA. NASA, Johnson Space Ctr, Astronaut Off, Houston, TX USA. NASA, Johnson Space Ctr, Flight Surgeon Off, Houston, TX USA. RP Rafiq, A (reprint author), Virginia Commonwealth Univ, Med Informat & Technol Appl Consortium, Dept Surg, 1101 E Marshall St,POB 980480, Richmond, VA 23298 USA. EM arafiq@vcu.edu NR 13 TC 9 Z9 9 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD APR PY 2005 VL 76 IS 4 BP 385 EP 391 PG 7 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 912VT UT WOS:000228108700012 PM 15828640 ER PT J AU Thierry-Palmer, M Cephas, S Sayavongsa, P Doherty, A Arnaud, SB AF Thierry-Palmer, M Cephas, S Sayavongsa, P Doherty, A Arnaud, SB TI Dahl salt-sensitive rats develop hypovitaminosis D and hyperparathyroidism when fed a standard diet SO BONE LA English DT Article DE 25-hydroxyvitamin D; parathyroid hormone; 1,25-dihydroxyvitamin D; sodium; aging ID VITAMIN-D METABOLISM; D-BINDING-PROTEIN; ESSENTIAL-HYPERTENSION; NEPHROTIC SYNDROME; BLOOD-PRESSURE; PARATHYROID FUNCTION; 25-HYDROXYVITAMIN D; CALCIURIC RESPONSE; URINARY CALCIUM; D INSUFFICIENCY AB The Dahl salt-sensitive rat (S), a model for salt-sensitive hypertension, excretes protein-bound 25-hydroxyvitamin D (25-OHD) into urine when fed a low salt diet. Urinary 25-OHD increases during high salt intake. We tested the hypothesis that continuous loss of 25-OHD into urine would result in low plasma 25-OHD concentration in mature S rats raised on a standard diet. Dahl S and salt-resistant (R) male rats were raised to maturity (12-month-old) on a commercial rat diet (1% salt) and switched to 0.3% (low) or 2% (high) salt diets 3 weeks before euthanasia. Urine (24 h) was collected at the end of the dietary treatments. Urinary 25-OHD and urinary 25-OHD binding activity of S rats were three times that of R rats, resulting in lower plasma 25-OHD and 24,25-dihydroxyvitamin D concentrations in S rats than in R rats (P < 0.001). Plasma parathyroid hormone concentrations of S rats were twice that of R rats. S rats fed 2% salt had higher plasma 1,25dihydroxyvitamin D concentrations than those fed 0.3% salt (P = 0.002). S rats excreted more calcium into urine than R rats (P < 0.001) and did not exhibit the expected calciuric response to salt. Proteinuria of the S rats was three times that of the R rats, suggesting kidney damage in the S rats. Low plasma 25-OHD and 24,25-dihydroxyvitamin D and high plasma 1,25-dihydroxyvitamin D and PTH concentrations seen in the mature S rats have also been reported for elderly patients with low-renin (salt-induced) hypertension. An implication of this study is that low vitamin D status may occur with age in salt-sensitive individuals, even when salt intake is normal. © 2005 Elsevier Inc. All rights reserved. C1 Morehouse Sch Med, Dept Biochem, Atlanta, GA 30310 USA. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Thierry-Palmer, M (reprint author), Morehouse Sch Med, Dept Biochem, 720 Westview Dr, Atlanta, GA 30310 USA. EM mthierry-palmer@msn.edu FU NCRR NIH HHS [RR03034] NR 51 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 8756-3282 J9 BONE JI Bone PD APR PY 2005 VL 36 IS 4 BP 645 EP 653 DI 10.1016/j.bone.2005.01.016 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 924NX UT WOS:000228986600007 PM 15784187 ER PT J AU Baker, T Granat, R Clayton, RW AF Baker, T Granat, R Clayton, RW TI Real-time earthquake location using Kirchhoff reconstruction SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SOUTHERN CALIFORNIA; ALGORITHM AB Real-time location of earthquakes can be achieved by using direct imaging of the recorded wave field based on a Kirchhoff reconstruction method similar to that used in the migration of seismic reflection data. The standard method of event location requires the wave arrival at each sensor to be picked and associated with an event. By using direct imaging, the event is identified once in the imaged wave field. The computation is independent of the level of seismic activity and can be carried out on a typical desktop computer. The procedure has been successfully demonstrated in two and three dimensions using data from the Southern California Seismic Network (Trinet). At higher resolutions, the reconstruction method can identify finite source effects. Further work considers extending the method by implementing full elastic theory and solving for moment tensors at all locations in the mesh. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Seismol Lab, Pasadena, CA 91125 USA. RP Baker, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-233, Pasadena, CA 91109 USA. NR 20 TC 29 Z9 29 U1 0 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD APR PY 2005 VL 95 IS 2 BP 699 EP 707 DI 10.1785/0120040123 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 925CF UT WOS:000229028400023 ER PT J AU Renaud, ML Williams, JA AF Renaud, ML Williams, JA TI Kemp's ridley sea turtle movements and migrations SO CHELONIAN CONSERVATION AND BIOLOGY LA English DT Article DE Reptilia; Testudines; Cheloniidae; Lepidochelys kempii; sea turtle; seasonal migration; telemetry; movements; diving behavior; USA ID SUBMERGENCE PATTERNS; CARETTA-CARETTA; CAROLINA; WATERS; MORTALITY; BEHAVIOR; COAST AB The Kemp's ridley, Lepidochelys kempii, is the most endangered of all sea turtles. It is distributed throughout the Gulf of Mexico and occurs along the eastern seaboard of North America to Nova Scotia. Isolated occurrences have been documented in the eastern north Atlantic and Caribbean. Its presence in U.S. waters is seasonal, with sea water temperature playing an important role in the distribution of the species. In the Gulf of Mexico, Kemp's ridleys arrive at northern coastal feeding areas in the spring and migrate south in the fall. Occurrence on the east coast of North America is more common during June, July, and August. Kemp's ridleys are typically found in water depths < 20 m from April through September, and they move out to 50-m depths during October through March. Movement year-round appears to be nearshore (within 18 m) and parallel to shorelines. Mean submergence duration of Kemp's ridleys is > 30 min in the winter and less than 15 min during other seasons. Single dive durations range from less than 1 min to over 4 hrs. Kemp's ridleys spend up to 96% of their time submerged. Mean movement of satellite- and radio-tracked turtles was 26.6 and 8.8 km/day, respectively. C1 Natl Marine Fisheries Serv, Galveston Lab, SE Fisheries Ctr, Galveston, TX 77551 USA. RP Williams, JA (reprint author), 73-4328 Hua Pl, Kailua Kona, HI 96740 USA. EM Jo.Anne.Williams@noaa.gov NR 52 TC 5 Z9 11 U1 1 U2 16 PU CHELONIAN RESEARCH FOUNDATION PI LUNENBURG PA 168 GOODRICH ST., LUNENBURG, MA USA SN 1071-8443 J9 CHELONIAN CONSERV BI JI Chelonian Conserv. Biol. PD APR PY 2005 VL 4 IS 4 BP 808 EP 816 PG 9 WC Zoology SC Zoology GA 964JG UT WOS:000231876400009 ER PT J AU Fontaine, C Shaver, D AF Fontaine, C Shaver, D TI Head-starting the Kemp's ridley sea turtle, Lepidochelys kempii, at the NMFS Galveston Laboratory, 1978-1992: A review SO CHELONIAN CONSERVATION AND BIOLOGY LA English DT Article DE Reptilia; Testudines; Cheloniidae; Lepidochelys kempii; sea turtle; management; conservation; head-start; review; USA ID NORTHWESTERN GULF; MEXICO AB We review the Kemp's ridley sea turtle head-start experiment at the National Marine Fisheries Service (NMFS) Galveston Laboratory which was part of an international effort to save this endangered species from 1978 through 1992. During the 15 years of this experiment 22,596 tagged yearling turtles were released into the Gulf of Mexico, of which 878 were recaptured either dead or alive. Through 2000, ten adult head-started Kemp's ridleys have returned and nested; nine at North Padre Island and Mustang Island, Texas (near where they had been experimentally imprinted) and one at the primary nesting beach on the east coast of Mexico near Rancho Nuevo. C1 US Dept Commerce, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr,Galveston Lab, Galveston, TX 77551 USA. US Natl PArl Serv, Padre Isl Natl Seashore, Corpus Christi, TX 78480 USA. RP Fontaine, C (reprint author), US Dept Commerce, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr,Galveston Lab, 4700 Ave U, Galveston, TX 77551 USA. EM tim.fontaine@noaa.gov; donna_shaver@nps.gov NR 44 TC 17 Z9 20 U1 0 U2 11 PU CHELONIAN RESEARCH FOUNDATION PI LUNENBURG PA 168 GOODRICH ST., LUNENBURG, MA USA SN 1071-8443 J9 CHELONIAN CONSERV BI JI Chelonian Conserv. Biol. PD APR PY 2005 VL 4 IS 4 BP 838 EP 845 PG 8 WC Zoology SC Zoology GA 964JG UT WOS:000231876400013 ER PT J AU Lian, YS Liou, MS AF Lian, YS Liou, MS TI Mining of data from evolutionary algorithms for improving design optimization SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article DE evolutionary computation; data mining; optimization AB This paper focuses on integration of computational methods for design optimization based on data mining and knowledge discovery. We propose to use radial basis function neural networks to analyze the large database generated from evolutionary algorithms and to extract the cause-effect relationship, between the objective functions and the input design variables. The aim is to improve the optimization process by either reducing the computation cost or improving the optimal. Also, it is hoped to provide designers with the salient design pattern about the problem under consideration, from the physics-based simulations. The proposed technique is applied to both academic problems and real-world problems, including optimization of an airfoil and the turbopump of a cryogenic rocket engine. Our results demonstrate that these techniques can further improve the design already achieved by the evolutionary algorithms with a slightly additional cost. C1 Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lian, YS (reprint author), Univ Michigan, Ann Arbor, MI 48109 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU TECH SCIENCE PRESS PI ENCINO PA 4924 BALBOA BLVD, # 488, ENCINO, CA 91316 USA SN 1526-1492 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD APR PY 2005 VL 8 IS 1 BP 61 EP 72 PG 12 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 931OI UT WOS:000229494200005 ER PT J AU Kradinov, V Madenci, E Ambur, DR AF Kradinov, V Madenci, E Ambur, DR TI Bolted lap joints of laminates with varying thickness and metallic inserts SO COMPOSITE STRUCTURES LA English DT Article DE lap joints; bolt; inserts; laminate; virtual work AB An analysis method to determine the bolt load distribution in single- and double-lap joints is presented. The joints are made of laminates in which the bolt holes are reinforced with metallic inserts and the laminates may have variable thickness and lay-up. The solution method based on the combined complex potential and variational formulation satisfies the equilibrium equations exactly, and the boundary conditions and constraints are satisfied by minimizing the total potential. Under general loading conditions, this method is applied to multiple bolt configurations without requiring symmetry conditions while explicitly accounting for the contact phenomenon and the interaction among the bolts. (c) 2004 Elsevier Ltd. All rights reserved. C1 Univ Arizona, Dept Aeronaut & Mech Engn, Tucson, AZ 85721 USA. NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Madenci, E (reprint author), Univ Arizona, Dept Aeronaut & Mech Engn, 1130 N Mt Ave, Tucson, AZ 85721 USA. EM madenci@email.arizona.edu NR 5 TC 7 Z9 8 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD APR PY 2005 VL 68 IS 1 BP 75 EP 85 DI 10.1016/j.compstruct.2004.03.002 PG 11 WC Materials Science, Composites SC Materials Science GA 907CL UT WOS:000227692700009 ER PT J AU Delozier, DM Watson, KA Smith, JG Connell, JW AF Delozier, DM Watson, KA Smith, JG Connell, JW TI Preparation and characterization of space durable polymer nanocomposite films SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article ID WALL CARBON NANOTUBES; HYBRIDS AB Low color, flexible, space durable polyimide films with inherent, robust electrical conductivity have been under investigation as part of a continuing materials development activity for future NASA space missions involving Gossamer structures. Electrical conductivity is needed in these films to mitigate electrostatic charge build-up caused by charged species present in the orbital environment. One method of imparting conductivity is through the use of single-walled carbon nanotubes (SWNTs). SWNTs were dispersed in space durable polyimide films in the bulk using a solution technique and on the surface using a spray coating technique. The resultant nanocomposite films were evaluated for electrical conductivity, mechanical, and optical properties. The results of this study will be presented. (c) 2004 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Natl Inst Aerosp Res, Hampton, VA 23666 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. EM j.w.connell@larc.nasa.gov NR 20 TC 37 Z9 37 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD APR PY 2005 VL 65 IS 5 SI SI BP 749 EP 755 DI 10.1016/j.compscitech.2004.10.026 PG 7 WC Materials Science, Composites SC Materials Science GA 909OL UT WOS:000227869100007 ER PT J AU Freitas, SR Longo, KM Diasb, MAFS Diasb, PLS Chatfield, R Prins, E Artaxo, P Grell, GA Recuero, FS AF Freitas, SR Longo, KM Diasb, MAFS Diasb, PLS Chatfield, R Prins, E Artaxo, P Grell, GA Recuero, FS TI Monitoring the transport of biomass burning emissions in South America SO ENVIRONMENTAL FLUID MECHANICS LA English DT Article DE aerosol transport; air pollution; atmospheric modeling; biomass burning; climate change; long-distance transport; weather forecast ID TROPOSPHERIC OZONE; MODEL DESCRIPTION; AMAZON BASIN; SCAR-B; SMOKE; AEROSOLS; CONVECTION; SULFUR; CLOUDS; BRAZIL AB The atmospheric transport of biomass burning emissions in the South American and African continents is being monitored annually using a numerical simulation of air mass motions; we use a tracer transport capability developed within RAMS (Regional Atmospheric Modeling System) coupled to an emission model. Mass conservation equations are solved for carbon monoxide (CO) and particulate material (PM2.5). Source emissions of trace gases and particles associated with biomass burning activities in tropical forest, savanna and pasture have been parameterized and introduced into the model. The sources are distributed spatially and temporally and assimilated daily using the biomass burning locations detected by remote sensing. Advection effects (at grid scale) and turbulent transport (at sub-grid scale) are provided by the RAMS parameterizations. A sub-grid transport parameterization associated with moist deep and shallow convection, not explicitly resolved by the model due to its low spatial resolution, has also been introduced. Sinks associated with the process of wet and dry removal of aerosol particles and chemical transformation of gases are parameterized and introduced in the mass conservation equation. An operational system has been implemented which produces daily 48-h numerical simulations (including 24-h forecasts) of CO and PM2.5, in addition to traditional meteorological fields. The good prediction skills of the model are demonstrated by comparisons with time series of PM2.5 measured at the surface. C1 NOAA, Res, Forecast Syst Lab, Boulder, CO USA. Univ Sao Paulo, BR-05508 Sao Paulo, Brazil. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NOAA, NESDIS, ORA, Madison, WI USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. EM sfreitas@cptec.inpe.br RI grell, georg/B-6234-2015; Freitas, Saulo/A-2279-2012; Leite da Silva Dias, Pedro/H-1183-2016; Artaxo, Paulo/E-8874-2010 OI grell, georg/0000-0001-5214-8742; Freitas, Saulo/0000-0002-9879-646X; Leite da Silva Dias, Pedro/0000-0002-4051-2962; Artaxo, Paulo/0000-0001-7754-3036 NR 54 TC 112 Z9 121 U1 2 U2 25 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1567-7419 EI 1573-1510 J9 ENVIRON FLUID MECH JI Environ. Fluid Mech. PD APR PY 2005 VL 5 IS 1-2 BP 135 EP 167 DI 10.1007/s10652-005-0243-7 PG 33 WC Environmental Sciences; Mechanics; Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Environmental Sciences & Ecology; Mechanics; Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA 937QD UT WOS:000229939700006 ER PT J AU Conway, E AF Conway, E TI Three Mile Island: A nuclear crisis in historical perspective SO ENVIRONMENTAL HISTORY LA English DT Book Review C1 Jet Propuls Lab, Pasadena, CA 91109 USA. RP Conway, E (reprint author), Jet Propuls Lab, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 USA SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 2005 VL 10 IS 2 BP 340 EP 342 PG 3 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA 929CL UT WOS:000229319600023 ER PT J AU Odegard, GM Gates, T Herring, HM AF Odegard, GM Gates, T Herring, HM TI Characterization of viscoelastic properties of polymeric materials through nanoindentation SO EXPERIMENTAL MECHANICS LA English DT Article DE dynamic viscoelasticity; instrumented indentation; nanotechnology ID NANOSCALE MECHANICAL-PROPERTIES; CONTACT STIFFNESS; MOLECULAR-WEIGHT; FORCE MODULATION; ELASTIC-MODULUS; INDENTATION; POLYETHYLENE; LOAD AB Nanoindentation testing was used to determine the dynamic viscoelastic properties of eight polymer materials, which include three high-performance polymers and five densities of high-density polyethylene. It was determined that varying the harmonic frequency of nanoindentation does not have a significant effect on the measured storage and loss moduli of the polymers. Agreement was found between these nanoindentation results and data from bulk dynamic mechanical testing of the same materials. Varying the harmonic amplitude of the nanoindentation had a limited effect on the measured viscoelastic properties of the resins. However, storage and loss moduli from nanoindentation were shown to be sensitive to changes in the density of the polyethylene. C1 Michigan Technol Univ, Dept Mech Engn, Houghton, MI 49931 USA. NASA, Langley Res Ctr, Lockheed Martin Space Operat, Hampton, VA 23681 USA. RP Odegard, GM (reprint author), Michigan Technol Univ, Dept Mech Engn, Houghton, MI 49931 USA. EM gmodegar@mtu.edu OI Odegard, Gregory/0000-0001-7577-6565 NR 22 TC 111 Z9 112 U1 3 U2 29 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD APR PY 2005 VL 45 IS 2 BP 130 EP 136 DI 10.1177/0014485105052320 PG 7 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA 909SY UT WOS:000227882200004 ER PT J AU Ruggerone, GT Farley, E Nielsen, J Hagen, P AF Ruggerone, GT Farley, E Nielsen, J Hagen, P TI Seasonal marine growth of Bristol Bay sockeye salmon (Oncorhynchus nerka) in relation to competition with Asian pink salmon (O-gorbuscha) and the 1977 ocean regime shift SO FISHERY BULLETIN LA English DT Article ID ARCTIC NORTH PACIFIC; ZOOPLANKTON BIOMASS; ANNULUS FORMATION; BERING SEA; CLIMATE; ALASKA; GULF; VARIABILITY; SCALES; LIFE AB Recent research demonstrated significantly lower growth and survival of Bristol Bay sockeye salmon (Oncorhynchus nerka) during odd-numbered years of their second or third years at sea (1975, 1977, etc.), a trend that was opposite that of Asian pink salmon (O. gorbuscha) abundance. Here we evaluated seasonal growth trends of Kvichak and Egegik river sockeye salmon (Bristol Bay stocks) during even- and odd-numbered years at sea by measuring scale circuli increments within each growth zone of each major salmon age group between 1955 and 2000. First year scale growth was not significantly different between odd- and even-numbered years, but peak growth of age-2. smolts was significantly higher than age-1. smolts. Total second and third year scale growth of salmon was significantly lower during odd- than during even-numbered years. However, reduced scale growth in odd-numbered years began after peak growth in spring and continued through summer and fall even though most pink salmon had left the high seas by late July (10-18% growth reduction in odd vs. even years). The alternating odd and even year growth pattern was consistent before and after the 1977 ocean regime shift. During 1977-2000, when salmon abundance was relatively great, sockeye salmon growth was high during specific seasons compared with that during 1955-1976, that is to say, immediately after entry to Bristol Bay, after peak growth in the first year, during the middle of the second growing season, and during spring of the third season. Growth after the spring peak in the third year at sea was relatively low during 1977-2000. We hypothesize that high consumption rates of prey by pink salmon during spring through mid-July of odd-numbered years, coupled with declining zooplankton biomass during summer and potentially cyclic abundances of squid and other prey, contributed to reduced prey availability and therefore reduced growth of Bristol Bay sockeye salmon during late spring through fall of odd-numbered years. C1 Nat Resources Consultants Inc, Seattle, WA 98119 USA. Natl Marine Fisheries Serv, Juneau, AK 99801 USA. US Geol Survey, Biol Resources Div, Anchorage, AK 99503 USA. Alaska Dept Fish & Game, Juneau, AK 99802 USA. RP Ruggerone, GT (reprint author), Nat Resources Consultants Inc, 1900 W Nickerson St,Suite 207, Seattle, WA 98119 USA. EM GRuggerone@nrccorp.com NR 51 TC 30 Z9 34 U1 0 U2 8 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2005 VL 103 IS 2 BP 355 EP 370 PG 16 WC Fisheries SC Fisheries GA 927BG UT WOS:000229166800011 ER PT J AU Kharecha, P Kasting, J Siefert, J AF Kharecha, P. Kasting, J. Siefert, J. TI A coupled atmosphere-ecosystem model of the early Archean Earth SO GEOBIOLOGY LA English DT Review AB A coupled photochemical-ecosystem model has been developed to simulate the early Archean biosphere. The model incorporates kinetic and nutrient limitations on biological productivity, along with constraints imposed by metabolic thermodynamics. We have used this model to predict the biogenic CH4 flux and net primary productivity (NPP) of the marine biosphere prior to the advent of oxygenic photosynthesis. Organisms considered include chemotrophic and organotrophic methanogens, H-2-, H2S-, and Fe-using anoxygenic phototrophs, S-reducing bacteria, CO-using acetogens, and fermentative bacteria. CH4 production and NPP in our model are limited by the downward flux of H-2, CO, S-8, and H2S through the atmosphere-ocean interface and by the upwelling rate of Fe2+ from the deep oceans. For reasonable estimates of the supply rates of these compounds, we find that the biogenic CH4 flux should have ranged from approximately (1)/(3) to 2.5 times the modern CH4 flux. In the anoxic Archean atmosphere, this would have produced CH4 concentrations of 100 ppmv to as much as 35 000 ppmv (3.5%), depending on the rate at which hydrogen escaped to space. Recent calculations indicating that hydrogen escape was slow favour the higher CH4 concentrations. Calculated NPP is lower than in the modern oceans by a factor of at least 40. In our model, H-2-based metabolism is moderately more productive than Fe2+-based metabolism, with S-based metabolism being considerably less productive. Internal recycling of sulphur within the surface ocean could conceivably raise rates of sulphur metabolism by a factor of 10 higher than the values predicted by our model. Although explicit climate calculations have not been performed here, our results are consistent with the idea that the Archean climate was warm, and possibly very hot. Some or most of our ecosystem scenarios are consistent with the carbon isotope record, depending on how that record is interpreted. If the conventional view is correct and organic carbon burial accounted for approximately 20% of total carbon burial during the Archean, then only two of our phototroph-based model ecosystems are plausible. However, if a recent alternative analysis is correct and only approximately 0-10% of total buried carbon was organic, then essentially all of our anaerobic ecosystems are plausible. A better understanding of both the geochemical and the biological records is needed to better constrain our models. C1 [Kharecha, P.; Kasting, J.] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. [Kharecha, P.; Kasting, J.] Penn State Univ, Astrobiol Res Ctr, University Pk, PA 16802 USA. [Siefert, J.] Rice Univ, Dept Stat, Houston, TX 77251 USA. [Kharecha, P.] Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Kharecha, P (reprint author), Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. EM pushker@essc.psu.edu FU NASA Exobiology; NSF FX Funding for this work was provided by the NASA Exobiology and NSF LExEn programs. We thank our Penn State colleagues Lee Kump, Blair Hedges, and Chris House for their valuable feedback. NR 101 TC 111 Z9 119 U1 2 U2 49 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1472-4677 EI 1472-4669 J9 GEOBIOLOGY JI Geobiology PD APR PY 2005 VL 3 IS 2 BP 53 EP 76 DI 10.1111/j.1472-4669.2005.00049.x PG 24 WC Biology; Environmental Sciences; Geosciences, Multidisciplinary SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Geology GA V06CN UT WOS:000207171800001 ER PT J AU Buchanan, PC Noguchi, T Bogard, DD Ebihara, M Katayama, I AF Buchanan, PC Noguchi, T Bogard, DD Ebihara, M Katayama, I TI Glass veins in the unequilibrated eucrite Yamato 82202 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PARENT BODY; METEORITES; PETROLOGY; HISTORY; ORIGIN; VESTA; METAMORPHISM; ACHONDRITES; CHONDRITES; DIOGENITES AB The unequilibrated eucrite Yamato 82202 (Y82202) contains a network of relatively thick (up to 1 mm in width) glass veins. The host of the meteorite represents a monomict breccia composed of volcanic rock that crystallized > 4.3 Ga ago as a lava flow on the surface of 4 Vesta. The veins formed 3.90 +/- 0.04 Ga ago, probably as a result of frictional melting associated with impact, under conditions of low effective oxygen fugacity and higher sulfur fugacity. The glass contains disordered structural elements characteristic of pyroxene and feldspar, reminiscent of the eucritic target lithology. The unequilibrated pyroxenes of the volcanic host and the pristine character of the glass indicate that this meteoritic material did not experience significant thermal metamorphism after initial crystallization of the lava. Hence, it was not affected by regional metamorphism caused by burial to a significant depth or by long-term contact metamorphism associated with a thick lava flow, large intrusion, or hot layer of impact ejecta. The meteorite resided at a shallow depth (though not at the surface) on 4 Vesta or on one of the vestoids until it was ejected and traveled to Earth, probably with other HED materials that have Ar-36 exposure ages of similar to 13 Ma. These data suggest that the surface of the asteroid 4 Vesta has significant, though probably small, proportions of glass, as well as unequilibrated volcanic rock. Copyright (c) 2005 Elsevier Ltd. C1 Natl Inst Polar Res, Antarctic Meteorite Res Ctr, Itabashi Ku, Tokyo 1738515, Japan. Ibaraki Univ, Dept Mat & Biol Sci, Mito, Ibaraki 3108512, Japan. NASA, Johnson Space Ctr, Astromat Res, Houston, TX 77058 USA. Tokyo Metropolitan Univ, Grad Sch Sci, Dept Chem, Hachioji, Tokyo 1920397, Japan. Tokyo Inst Technol, Dept Earth & Planetary Sci, Tokyo 1528551, Japan. RP Buchanan, PC (reprint author), Natl Inst Polar Res, Antarctic Meteorite Res Ctr, Itabashi Ku, 1-9-10 Kaga, Tokyo 1738515, Japan. EM buchanan@nipr.ac.jp RI Katayama, Ikuo/A-9611-2011 NR 36 TC 10 Z9 10 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD APR 1 PY 2005 VL 69 IS 7 BP 1883 EP 1898 DI 10.1016/j.gca.2004.08.022 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916EC UT WOS:000228367200018 ER PT J AU Jolly, WM Nemani, R Running, SW AF Jolly, WM Nemani, R Running, SW TI A generalized, bioclimatic index to predict foliar phenology in response to climate SO GLOBAL CHANGE BIOLOGY LA English DT Article DE climate change; global; minimum temperature; model; phenology; photoperiod; vapor pressure deficit ID NORTHERN HARDWOOD FOREST; LEAF-AREA INDEX; SATELLITE DATA; PLANT PHENOLOGY; GROWING-SEASON; WATER-STRESS; BUD BURST; MODEL; TEMPERATURE; VEGETATION AB The phenological state of vegetation significantly affects exchanges of heat, mass, and momentum between the Earth's surface and the atmosphere. Although current patterns can be estimated from satellites, we lack the ability to predict future trends in response to climate change. We searched the literature for a common set of variables that might be combined into an index to quantify the greenness of vegetation throughout the year. We selected as variables: daylength (photoperiod), evaporative demand (vapor pressure deficit), and suboptimal (minimum) temperatures. For each variable we set threshold limits, within which the relative phenological performance of the vegetation was assumed to vary from inactive (0) to unconstrained (1). A combined Growing Season Index (GSI) was derived as the product of the three indices. Ten-day mean GSI values for nine widely dispersed ecosystems showed good agreement (r > 0.8) with the satellite-derived Normalized Difference Vegetation Index (NDVI). We also tested the model at a temperate deciduous forest by comparing model estimates with average field observations of leaf flush and leaf coloration. The mean absolute error of predictions at this site was 3 days for average leaf flush dates and 2 days for leaf coloration dates. Finally, we used this model to produce a global map that distinguishes major differences in regional phenological controls. The model appears sufficiently robust to reconstruct historical variation as well as to forecast future phenological responses to changing climatic conditions. C1 Univ Montana, Coll Forestry & Conservat, NTSG, Missoula, MT 59812 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jolly, WM (reprint author), Univ Montana, Coll Forestry & Conservat, NTSG, SC428, Missoula, MT 59812 USA. EM mattj@ntsg.umt.edu NR 64 TC 178 Z9 183 U1 5 U2 63 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD APR PY 2005 VL 11 IS 4 BP 619 EP 632 DI 10.1111/j.1365-2486.2005.00930.x PG 14 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 913UP UT WOS:000228179500009 ER PT J AU Kroes, R Montenbruck, O Bertiger, W Visser, P AF Kroes, R Montenbruck, O Bertiger, W Visser, P TI Precise GRACE baseline determination using GPS SO GPS SOLUTIONS LA English DT Article DE spacecraft formation flying; relative positioning; GRACE; integer ambiguity resolution AB Precision relative navigation is an essential aspect of spacecraft formation flying missions, both from an operational and a scientific point of view. When using GPS as a relative distance sensor, dual-frequency receivers are required for high accuracy at large inter-satellite separations. This allows for a correction of the relative ionospheric path delay and enables double difference integer ambiguity resolution. Although kinematic relative positioning techniques demonstrate promising results for hardware-in-the-loop simulations, they were found to lack an adequate robustness in real-world applications. To overcome this limitation, an extended Kalman Filter modeling the relative spacecraft dynamics has been developed. The filter processes single difference GPS pseudorange and carrier phase observations to estimate the relative position and velocity along with empirical accelerations and carrier phase ambiguities. In parallel, double difference carrier phase ambiguities are resolved on both frequencies using the least square ambiguity decorrelation adjustment (LAMBDA) method in order to fully exploit the inherent measurement accuracy. The combination of reduced dynamic filtering with the LAMBDA method results in smooth relative position estimates as well as fast and reliable ambiguity resolution. The proposed method has been validated with data from the gravity recovery and climate experiment (GRACE) mission. For an 11-day data arc, the resulting solution matches the GRACE K-Band Ranging System measurements with an accuracy of 1 mm, whereby 83% of the double difference ambiguities are resolved. C1 Delft Univ Technol, Dept Earth Observat & Space Syst, NL-2629 Delft, Netherlands. Deutsch Zentrum Luft & Raumfahrt, German Space Operat Ctr, D-82230 Weszling, Germany. Jet Propuls Lab, Pasadena, CA 91109 USA. RP Kroes, R (reprint author), Delft Univ Technol, Dept Earth Observat & Space Syst, Kluyverweg 1, NL-2629 Delft, Netherlands. EM r.kroes@lr.tudelft.nl OI Montenbruck, Oliver/0000-0003-4783-745X NR 16 TC 63 Z9 72 U1 0 U2 19 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 1080-5370 J9 GPS SOLUT JI GPS Solut. PD APR PY 2005 VL 9 IS 1 BP 21 EP 31 DI 10.1007/s10291-004-0123-5 PG 11 WC Remote Sensing SC Remote Sensing GA 917ZF UT WOS:000228507200003 ER PT J AU Komjathy, A Sparks, L Mannucci, AJ Coster, A AF Komjathy, A Sparks, L Mannucci, AJ Coster, A TI The ionospheric impact of the October 2003 storm event on Wide Area Augmentation System SO GPS SOLUTIONS LA English DT Article ID GLOBAL-POSITIONING-SYSTEM AB The United States Federal Aviation Administration's (FAA) Wide-Area Augmentation System (WAAS) for civil aircraft navigation is focused primarily on the Conterminous United States (CONUS). Other Satellite-Based Augmentation Systems (SBAS) include the European Geostationary Navigation Overlay Service (EGNOS) and the Japanese Multi-transport Satellite-based Augmentation System (MSAS). Navigation using WAAS requires accurate calibration of ionospheric delays. To provide delay corrections for single frequency global positioning system (GPS) users, the wide-area differential GPS systems depend upon accurate determination of ionospheric total electron content (TEC) along radio links. Dual-frequency transmissions from GPS satellites have been used for many years to measure and map ionospheric TEC on regional and global scales. The October 2003 solar-terrestrial events are significant not only for their dramatic scale, but also for their unique phasing of solar irradiance and geomagnetic events. During 28 October, the solar X-ray and EUV irradiances were exceptionally high while the geomagnetic activity was relatively normal. Conversely, 29-31 October was geomagnetically active while solar irradiances were relatively low. These events had the most severe impact in recent history on the CONUS region and therefore had a significant effect on the WAAS performance. To help better understand the event and its impact on WAAS, we examine in detail the WAAS reference site (WRS) data consisting of triple redundant dual-frequency GPS receivers at 25 different locations within the US. To provide ground-truth, we take advantage of the three co-located GPS receivers at each WAAS reference site. To generate ground-truth and calibrate GPS receiver and transmitter interfrequency biases, we process the GPS data using the Global Ionospheric Mapping (GIM) software developed at the Jet Propulsion Laboratory. This software allows us to compute calibrated high resolution observations of TEC. We found ionospheric range delays up to 35 m for the day-time CONUS during quiet conditions and up to 100 m during storm time conditions. For a quiet day, we obtained WAAS planar fit slant residuals less than 2 m (0.4 m root mean square (RMS)) and less than 25 m (3.4 in RMS) for the storm day. We also investigated ionospheric gradients, averaged over distances of a few hundred kilometers. The gradients were no larger than 0.5 m over 100 km for a quiet day. For the storm day, we found gradients at the 4 m level over 100 km. Similar level gradients are typically observed in the low-latitude region for quiet or storm conditions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. MIT, Haystack Observ, Westford, MA 01886 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 238-600, Pasadena, CA 91109 USA. EM Attila.Komjathy@jpl.nasa.gov RI Mannucci, Anthony/A-1349-2007 OI Mannucci, Anthony/0000-0003-2391-8490 NR 16 TC 19 Z9 24 U1 2 U2 8 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 1080-5370 EI 1521-1886 J9 GPS SOLUT JI GPS Solut. PD APR PY 2005 VL 9 IS 1 BP 41 EP 50 DI 10.1007/s10291-004-0126-2 PG 10 WC Remote Sensing SC Remote Sensing GA 917ZF UT WOS:000228507200005 ER PT J AU Wentworth, SJ Gibson, EK Velbel, MA McKay, DS AF Wentworth, SJ Gibson, EK Velbel, MA McKay, DS TI Antarctic Dry Valleys and indigenous weathering in Mars meteorites: Implications for water and life on Mars SO ICARUS LA English DT Article; Proceedings Paper CT 3rd International Conference on Mars Polar Science and Exploration CY OCT 13-17, 2003 CL Lake Louise, CANADA SP Lunar & Planetary Inst, NASA, NASA Mars Program Off, Canadian Space Agcy, Geol Survey Canada, Univ Alberta, Dept Earth & Atmospher Sci, Int Glaciol Soc DE mars, surface; Mars, climate; meteorites; regoliths ID MARTIAN METEORITES; AQUEOUS ALTERATION; NEAR-SURFACE; ANALOG; CARBONATE; PRODUCTS; MINERALS; SULFATE; DISSOLUTION; PERMAFROST AB The Dry Valleys of Antarctica are an excellent analog of the environment at the surface of Mars. Soil formation histories involving slow processes Of sublimation and migration of water-soluble ions in polar desert environments are characteristic of both Mars and the Dry Valleys. At the present time, the environment in the Dry Valleys is probably the most similar to that in the mid-latitudes on Mars although similar conditions may be found in areas of the polar regions during their respective Mars summers. It is thought that Mars is currently in an interglacial period, and that subsurface water ice is sublimating poleward. Because the Mars sublimation zones seem to be the most similar to the Antarctic Dry Valleys, the Dry Valleys-type Mars climate is migrating towards the poles. Mars has likely undergone drastic obliquity changes, which means that the Dry Valleys analog to Mars may be valid for large parts of Mars, including the polar regions, at different times in geologic history. Dry Valleys soils contain traces of silicate alteration products and secondary salts much like those found in Mars meteorites. A martian origin for some of the meteorite secondary phases has been verified previously; it can be based on the presence of shock effects and other features which Could not have formed after the rocks were ejected front Mars, or demonstrable modification of a feature by the passage of the meteorite through Earth's atmosphere (proving the feature to be pre-terrestrial). The martian weathering products provide critical information for deciphering the near-surface history of Mars. Definite martian secondary phases include Ca-carbonate, Ca-sulfate, and M-sulfate. These salts are also found in soils from the Dry Valleys of Antarctica. Results of earlier Wright Valley work are consistent with what is now known about Mars based on meteorite and orbital data. Results from recent and Current Mars missions support this inference. Aqueous processes are active even in permanently frozen Antarctic Dry Valleys soils, and similar processes are probably also occurring on Mars today. especially at the mid-latitudes. Both weathering products and life in Dry Valley,, soils are distributed heterogeneously. Such variations should be taken into account in future Studies of martian soils and also in the search for possible life on Mars. (c) 2004 Elsevier Inc. All rights reserved. C1 Lockheed Martin, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Michigan State Univ, Dept Geol Sci, E Lansing, MI 48824 USA. RP Lockheed Martin, Mail Code C23,2400 NASA Pkwy, Houston, TX 77058 USA. EM susan.j.wentworth@jsc.nasa.gov NR 49 TC 42 Z9 43 U1 2 U2 29 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD APR PY 2005 VL 174 IS 2 BP 383 EP 395 DI 10.1016/j.icarus.2004.08.026 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914JG UT WOS:000228223100008 ER PT J AU Hale, AS Bass, DS Tamppari, LK AF Hale, AS Bass, DS Tamppari, LK TI Monitoring the perennial martian northern polar cap with MGS MOC SO ICARUS LA English DT Article; Proceedings Paper CT 3rd International Conference on Mars Polar Science and Exploration CY OCT 13-17, 2003 CL Lake Louise, CANADA SP Lunar & Planetary Inst, NASA, NASA Mars Program Off, Canadian Space Agcy, Geol Survey Canada, Univ Alberta, Dept Earth & Atmospher Sci, Int Glaciol Soc DE Mars, surface; surfaces; planets; Mars, climate ID MARS ORBITER CAMERA; WATER ICE CAP; VIKING; RECESSION; VARIABILITY; DUST AB We have used the Mars Global Surveyor Mars Orbiter Camera Wide Angle (MGS MOC WA) dataset to study albedo trends on the martian northern residual cap. Six study regions were selected, the Chasma Boreale source region, three regions near the center of the cap ("fish hook" region, latitude = 87 degrees; "bottle opener" region, latitude = 87 degrees, "steep-shallow" region, latitude = 850), and two lower latitude regions (crater, latitude = 77 degrees, and polar outlier, latitude = 82 degrees), and the albedos of these six regions were examined. These regions were chosen due to their good temporal coverage in the MOC dataset, as well as having been studied by other researchers (Bass et al., 2000, Icarus 144, 382-396; Calvin and Titus, 2004, Lunar Planet. Sci. XXXV, Abstract 1455). The picture which emerges is complex. Most areas experience a combination of darkening and brightening through the northern summer; only one area consistently brightens (the polar outlier region). A good deal of interannual repeatability in each region's albedo behavior is seen, however. Possible causes for the observed complex behaviors include dust deposition from late summer storms, sintering of frost grains over the course of the summer, and cold trapping of volatiles on bright, cold surfaces. (c) 2004 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hale, AS (reprint author), CALTECH, Jet Prop Lab, MS 264-235,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM amy.s.hale@jpl.nasa.gov NR 27 TC 14 Z9 15 U1 1 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2005 VL 174 IS 2 BP 502 EP 512 DI 10.1016/j.icarus.2004.10.033 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914JG UT WOS:000228223100015 ER PT J AU Kuhlman, KR Allenbach, LB Ball, CL Fusco, WG La Duc, MT Kuhlman, GM Anderson, RC Stuecker, T Erickson, IK Benardini, J Crawford, RL AF Kuhlman, KR Allenbach, LB Ball, CL Fusco, WG La Duc, MT Kuhlman, GM Anderson, RC Stuecker, T Erickson, IK Benardini, J Crawford, RL TI Enumeration, isolation, and characterization of ultraviolet (UV-C) resistant bacteria from rock varnish in the Whipple Mountains, California SO ICARUS LA English DT Article; Proceedings Paper CT 3rd International Conference on Mars Polar Science and Exploration CY OCT 13-17, 2003 CL Lake Louise, CANADA SP Lunar & Planetary Inst, NASA, NASA Mars Program Off, Canadian Space Agcy, Geol Survey Canada, Univ Alberta, Dept Earth & Atmospher Sci, Int Glaciol Soc DE Mars; rock varnish; ultraviolet observations; exobiology ID DESERT VARNISH; RADIOCARBON MEASUREMENTS; MICROCOLONIAL FUNGI; COMMUNITY STRUCTURE; BACILLUS-SUBTILIS; MANGANESE; SURFACES; MICROORGANISMS; IDENTIFICATION; RADIATION AB The in situ search for life on Mars requires an understanding of the possible habitats available and the types of microbes that inhabit such environments on Earth. Rock varnish is ubiquitous in terrestrial deserts and has been suggested to exist on Mars. Data reported here show that there are very high numbers of bacteria (10(7)-10(8) g(-1) dry wt) associated with rock varnish collected in the hot desert of the Whipple Mountains, south of Death Valley, CA, USA. Some of the bacteria identified in the rock varnish from the Whipple Mountains are resistant to UV-C exposure. This suggests that habitats like rock varnish, if they occur in the martian polar regions where liquid water may be available, may provide niches for radiation-resistant life forms such as the bacteria observed in the Whipple Mountains varnish ecosystem. The UV-resistant microbes isolated represent a diverse group of genera, but all are from the order Actinomycetales (the genera Arthrobacter, Curtobacterium, Geodermatophilus, and Cellulomonas). They are metabolically versatile heterotrophs capable of growing on a variety of simple sugars. amino acids, organic acids and aromatic acids as sole carbon and energy sources. (c) 2005 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Idaho, Environm Biotechnol Inst, Moscow, ID 83844 USA. Univ Idaho, Dept Biol Sci, Moscow, ID 83844 USA. RP Kuhlman, KR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kkuhlman@jpl.nasa.gov NR 71 TC 21 Z9 21 U1 4 U2 13 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2005 VL 174 IS 2 BP 585 EP 595 DI 10.1016/j.icarus.2004.11.022 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914JG UT WOS:000228223100021 ER PT J AU Glenar, DA Hansen, G Bjoraker, G Smith, M Pearl, J Blaney, D AF Glenar, DA Hansen, G Bjoraker, G Smith, M Pearl, J Blaney, D TI Bright-region radiative properties within the Mars south polar cap (L-s=231) from near-infrared spectroscopic imaging SO ICARUS LA English DT Article; Proceedings Paper CT 3rd International Conference on Mars Polar Science and Exploration CY OCT 13-17, 2003 CL Lake Louise, CANADA SP Lunar & Planetary Inst, NASA, NASA Mars Program Off, Canadian Space Agcy, Geol Survey Canada, Univ Alberta, Dept Earth & Atmospher Sci, Int Glaciol Soc DE Mars; ices; infrared observations; spectroscopy ID INTERANNUAL VARIABILITY; DUST STORM; ICE; BEHAVIOR; TES; IMAGER; FROST; SIZE AB Near-infrared spectroscopic imaging of a bright region within the Mars seasonal south polar cap was conducted during southern spring (L-s = 231) near the 2003 opposition, using the NASA Infrared Telescope Facility. The measured spectra are well represented by CO2 ice with grain radius of 13 mm and admixed dust and water ice concentrations of 0.005 and 0.002 wt%, respectively. We present a representative spectral (0.2-100 mu m) surface albedo for the bright region. (c) 2004 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Planetary Sci Inst, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Glenar, DA (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. EM dave.glenar@gsfc.nasa.gov RI Smith, Michael/C-8875-2012; Bjoraker, Gordon/D-5032-2012 NR 23 TC 9 Z9 9 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 2005 VL 174 IS 2 BP 600 EP 603 DI 10.1016/j.icarus.2004.09.012 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 914JG UT WOS:000228223100023 ER PT J AU Meesters, AGCA De Jeu, RAM Owe, M AF Meesters, AGCA De Jeu, RAM Owe, M TI Analytical derivation of the vegetation optical depth from the microwave polarization difference index SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE microwave polarization difference index (MPDI); microwave radiometry; remote sensing; vegetation optical depth ID SOIL-MOISTURE; RETRIEVAL; EMISSION; METHODOLOGY; MODEL AB A numerical solution for the canopy optical depth in an existing microwave-based land surface parameter retrieval model is presented. The optical depth is derived from the microwave polarization difference index and the dielectric constant of the soil. The original procedure used an approximation in the form of a logarithmic decay function to define this relationship and was derived through a series of lengthy polynomials. These polynomials had to be recalculated when the scattering albedo or antenna incidence angle changes. The new procedure is computationally more efficient and accurate. C1 Vrije Univ Amsterdam, Fac Earth & Life Sci, Dept Hydrol & Geoenvironm Sci, NL-1081 HV Amsterdam, Netherlands. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Meesters, AGCA (reprint author), Vrije Univ Amsterdam, Fac Earth & Life Sci, Dept Hydrol & Geoenvironm Sci, De Boelelaan 1085, NL-1081 HV Amsterdam, Netherlands. EM richard.de.jeu@geo.falw.vu.nl NR 15 TC 95 Z9 98 U1 4 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD APR PY 2005 VL 2 IS 2 BP 121 EP 123 DI 10.1109/LGRS.2005.843983 PG 3 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 949NS UT WOS:000230796000006 ER PT J AU Yang, P Tsay, SC Wei, H Guo, G Ji, Q AF Yang, P Tsay, SC Wei, H Guo, G Ji, Q TI Remote sensing of cirrus optical and microphysical properties from ground-based infrared radiometric measurements - Part 1: A new retrieval method based on microwindow spectral signature SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE cirrus cloud; ground-based measurement; infrared spectrum; retrieval method ID MU-M WINDOW; CLOUD PROPERTIES; RADIATIVE PROPERTIES; CLIMATE; PARAMETERIZATION; TEMPERATURE; SCATTERING; RADIANCES; MODELS; SHEBA AB The surface radiance spectrum within the terrestrial infrared window (i.e., wavelengths between 8-12 mu m or wavenumhers between 833-1250 cm(-1)) is sensitive to the optical and microphysical properties of cirrus clouds. Numerous microwindows where atmospheric absorption is minimum exist in the spectral regions of 820-960 cm(-1) and 1100-1240 cm(-1). The minimum radiances at the microwindows in these two spectral regions can be fitted by using two linear lines. The slope of the fitting line for the spectral region of 820-960 cm(-1) is sensitive to the effective size of ice crystals within cirrus clouds, whereas the intercept of the fitting line for the spectral region of 1100-1240 cm(-1) is sensitive to the optical thickness of the clouds. Based on this spectral feature, a new retrieval method has been developed for simultaneously retrieving cirrus optical thickness and the effective particle size of ice crystals. Furthermore, the ice water path of cirrus clouds can be estimated from the retrieved values of cloud optical thickness and effective particle size. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Tsay, Si-Chee/J-1147-2014 NR 28 TC 6 Z9 7 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD APR PY 2005 VL 2 IS 2 BP 128 EP 131 DI 10.1109/LGRS.2005.844733 PG 4 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 949NS UT WOS:000230796000008 ER PT J AU Guo, G Ji, Q Yang, P Tsay, SC AF Guo, G Ji, Q Yang, P Tsay, SC TI Remote sensing of cirrus optical and microphysical properties from ground-based infrared radiometric measurements - Part II: Retrievals from CRYSTAL-FACE measurements SO IEEE GEOSCIENCE AND REMOTE SENSING LETTERS LA English DT Article DE cirrus cloud; Cirrus Regional Study of Tropical Anvils and Cirrus layers Florida area Cirrus Experiment (CRYSTAL-FACE); ground-based measurement; retrieval ID MU-M WINDOW; CLOUD PROPERTIES; TROPICAL CIRRUS; WATER-VAPOR; TEMPERATURE; AEROSOL; CEPEX AB The ground-based infrared radiance measurements acquired on July 14, 20, and 28, 2002 during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign have been used for simultaneously retrieving the optical thickness and effective particle size on the basis of the retrieval algorithm reported in. the preceding counterpart of this paper. The corresponding ice water path is derived from the retrieved optical thickness and effective particle size. Specifically, the data used for the retrieval include: 1) the infrared radiance spectrum observed by an atmospheric emitted radiance interferometer at the surface; 2) the sky condition and cloud height determined from a sky imager and a micropulse lidar; and 3) the sounding data for the profiles of temperature, pressure, and relative humidity. For these three case studies, the retrieved cirrus optical thickness, effective particle size, and ice water path are in the range of 0.2-1.5, 18-42 mu m, and 2-15 g (.) m(-2), respectively. Furthermore, error analyses show that the retrieval uncertainties of the optical thickness and effective particle size are less than 15% if the uncertainty of water vapor vertical profile is within 5%. The retrieval errors are within 10% if the uncertainty of cloud temperature is within 7 K. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Guo, G (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Tsay, Si-Chee/J-1147-2014 NR 17 TC 4 Z9 4 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1545-598X J9 IEEE GEOSCI REMOTE S JI IEEE Geosci. Remote Sens. Lett. PD APR PY 2005 VL 2 IS 2 BP 132 EP 135 DI 10.1109/LGRS.2005.844734 PG 4 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 949NS UT WOS:000230796000009 ER PT J AU Varghese, SM Isakson, MJ AF Varghese, SM Isakson, MJ TI The calibration of a laser light line scan method for determining local interface roughness of the ocean floor SO IEEE JOURNAL OF OCEANIC ENGINEERING LA English DT Article DE acoustic scattering; imaging; marine sediments; scattering parameters measurement ID SEDIMENT; SYSTEM; WAVE AB An accurate model of acoustic interaction with sandy sediments is crucial to the application of SONAR in shallow-water environments. Because acoustic scattering from interface roughness plays a major role in the reverberation from and penetration into sandy sediments, it is imperative to be able to accurately measure the roughness of the sediment/water interface. An interface roughness measurement system has been developed in which a laser light sheet is projected onto the ocean floor. A resulting image can then be analyzed to determine the interface roughness. The system has been shown to achieve a height measurement error of less than 0.9 nun over a spatial frequency range of 15 to 60 cycles/m with about 0.5 mm standard deviation. These spatial frequencies correspond to acoustic Bragg frequencies of 11 to 45 kHz for backscattering applications. The error in wavelength was less than 5 rum with a standard deviation of about 1.0 mm. The system is inexpensive, easily deployable and automated in terms of data extraction. This system could greatly aid in determining the local interface profile for in situ acoustic scattering experiments. C1 NASA, Lyndon B Johnson Space Ctr, Lockheed Martin, Houston, TX 77058 USA. Univ Texas, Appl Res Labs, Austin, TX 78713 USA. RP Varghese, SM (reprint author), NASA, Lyndon B Johnson Space Ctr, Lockheed Martin, Houston, TX 77058 USA. EM sujamv@mail.utexas.edu; misakson@arlut.utexas.edu NR 10 TC 4 Z9 4 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0364-9059 J9 IEEE J OCEANIC ENG JI IEEE J. Ocean. Eng. PD APR PY 2005 VL 30 IS 2 BP 463 EP 467 DI 10.1109/JOE.2004.837140 PG 5 WC Engineering, Civil; Engineering, Ocean; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA 979LA UT WOS:000232942300025 ER PT J AU Watson, MD Ashley, PR Guenthner, AJ Abushagur, MAG AF Watson, MD Ashley, PR Guenthner, AJ Abushagur, MAG TI Modeling of electrooptic polymer electrical characteristics in a three-layer optical waveguide modulator SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE electrooptic polymer; frequency response; Mach-Zehnder (MZ) modulator; waveguide; waveguide layer adhesion; waveguide reactance AB The electrical characteristics of electrooptic polymer waveguide modulators are often described by the bulk reactance of the individual layers. However, the resistance and capacitance between the layers can significantly alter the electrical performance of a waveguide modulator. These interface characteristics are related to the boundary charge density and are strongly affected by the adhesion of the layers in the waveguide stack. An electrical reactance model has been derived to investigate this phenomenon at low frequencies. The model shows the waveguide stack frequency response has no limiting effects below the microwave range and that a true dc response requires a stable voltage for over 1000 h. Thus, reactance of the layers is the key characteristic of optimizing the voltage across the core layer, even at very low frequencies (> 10(-6) Hz). The results of the model are compared with experimental data for two polymer systems and show quite good correlation. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. USA, Aviat & Missile Res Dev & Engn Ctr, Huntsville, AL 35749 USA. USN, Air Warfare Ctr, China Lake, CA 93555 USA. Rochester Inst Technol, Kate Gleason Coll Engn, Rochester, NY 14623 USA. RP Watson, MD (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM Michael.D.Watson@nasa.gov; P.R.Ashley@redstone.rdec.army.mil; andrew.guenthner@navy.mil; maaeen@rit.edu NR 16 TC 1 Z9 1 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 2005 VL 41 IS 4 BP 589 EP 595 DI 10.1109/JQE.2005.843607 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 909PB UT WOS:000227870800016 ER PT J AU Zhong, H Xu, JZ Xie, X Yuan, T Reightler, R Madaras, E Zhang, XC AF Zhong, H Xu, JZ Xie, X Yuan, T Reightler, R Madaras, E Zhang, XC TI Nondestructive defect identification with terahertz time-of-flight tomography SO IEEE SENSORS JOURNAL LA English DT Article DE nondestructive identification; terahertz (THz) imaging; THz technology; THz time-domain spectroscopy; time-of-flight (TOF); tomography ID PULSES AB We demonstrate the application of terahertz (THz) time-of-flight tomographic imaging to identify the distribution of defects in foam materials. Based on THz time-domain spectroscopy technology, THz imaging probes targets with picosecond pulses of broad-band radiation in the frequency range from 100 GHz to 3 THz. The reflected THz wave from the target is measured using electrooptic sampling, which provides two-dimensional images with phase and amplitude information, as well as the spectroscopic properties of the object. The depth information is recorded in the THz time-domain waveform. Several reconstruction models are developed for tomographic imaging of defects inside foam. Foam insulation of space shuttle fuel tanks, with prebuilt defects, are investigated with THz tomographic imaging. Most prebuilt defects are pinpointed and models used to identify different kinds of defects are discussed. C1 Rensselaer Polytech Inst, Ctr Terahertz Res, Troy, NY 12180 USA. Rensselaer Polytech Inst, Ctr Subsurface Imaging & Sensing, Troy, NY 12180 USA. Lockheed Martin Space Syst, Sunnyvale, CA 94086 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Zhong, H (reprint author), Rensselaer Polytech Inst, Ctr Terahertz Res, Troy, NY 12180 USA. EM zhongh@rpi.edu; xuj@rpi.edu; xiex@rpi.edu; yuant@rpi.edu; ron.reightler@maf.nasa.gov; e.i.madaras@larc.nasa.gov; zhangxc@rpi.edu RI Zhang, Xi-Cheng/G-1306-2016 OI Zhang, Xi-Cheng/0000-0003-3721-1357 NR 16 TC 64 Z9 67 U1 0 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1530-437X J9 IEEE SENS J JI IEEE Sens. J. PD APR PY 2005 VL 5 IS 2 BP 203 EP 208 DI 10.1109/JSEN.2004.841341 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Applied SC Engineering; Instruments & Instrumentation; Physics GA 909OS UT WOS:000227869800013 ER PT J AU De Haag, MU Sayre, J Campbell, J Young, SD Gray, RA AF De Haag, MU Sayre, J Campbell, J Young, SD Gray, RA TI Terrain database integrity monitoring for synthetic vision systems SO IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS LA English DT Article AB A real-time terrain database integrity monitor for synthetic vision systems (SVS) that are to be used in civil aviation is presented. SVS provides pilots with advanced display technology including terrain information as well as other information about the external environment such as obstacles and traffic. The use of SVS to support strategic and tactical decision-making and the compelling nature of the terrain depiction may require terrain database server certification at the essential and flight-critical levels. SVS and terrain database characteristics are discussed and a failure model is identified. Real-time integrity monitors are proposed that check the consistency between terrain profiles described by the database and terrain profiles that are sensed in flight by either a downward-looking (DWL) sensor or a forward-looking (FWL) sensor. A DWL sensor scheme is discussed in detail and it is shown that this scheme can provide the necessary integrity required for an essential certification of a terrain database server. C1 Ohio Univ, Sch Elect Engn, Stocker Ctr, Athens, OH 45701 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Penn State Univ, Sch Engn & Engn Technol, Erie, PA 16563 USA. RP De Haag, MU (reprint author), Ohio Univ, Sch Elect Engn, Stocker Ctr, CS 329, Athens, OH 45701 USA. EM uijtdeha@ohio.edu; steven.d.young@nasa.gov; rxg31@psu.edu NR 32 TC 3 Z9 3 U1 2 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9251 J9 IEEE T AERO ELEC SYS JI IEEE Trans. Aerosp. Electron. Syst. PD APR PY 2005 VL 41 IS 2 BP 386 EP 406 PG 21 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 938CD UT WOS:000229976600001 ER PT J AU Pogorzelski, RJ AF Pogorzelski, RJ TI A 5-by-5 element coupled oscillator-based phased array SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE mutual injection locking; phased array; voltage controlled oscillator ID DYNAMICS AB Design, fabrication, and test of a 25-element planar coupled oscillator based phased array is described. The array operates at S-band and is shown to produce an agile beam which is steerable via adjustment of the perimeter oscillator tuning biases only. A phase diagnostic system is described which displays the aperture phase distribution during the far field measurements of the radiated beam. Measured results are presented both with and without the diagnostic system present. Without the diagnostic system, the beam pointing was achieved by setting the perimeter oscillator biases to be values previously used in the measurements with the diagnostic system present. The far field was then measured without the benefit of a knowledge of the aperture phase distribution. Finally, the results of far field measurements are described in which the beam position was incremented from a position previously measured with the diagnostic system in place to a new position by incrementing the perimeter oscillator biases by a fixed amount. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pogorzelski, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM pogo@jpl.nasa.gov NR 17 TC 15 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD APR PY 2005 VL 53 IS 4 BP 1337 EP 1345 DI 10.1109/TAP.2005.844395 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 913YV UT WOS:000228192400010 ER PT J AU Fischman, MA Berkun, AC Chun, W Im, E Andraka, RJ AF Fischman, MA Berkun, AC Chun, W Im, E Andraka, RJ TI An onboard processor and adaptive scanning controller for the second-generation precipitation radar SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE fault tolerance; field-programmable gate arrays (FPGAs); Global Precipitation Measurement (GPM) Mission; pulse compression; rain; real-time processing and control; spaceborne radar; Tropical Rainfall Measuring Mission (TRMM) AB Technology for the 14- and 35-GHz Second-Generation Precipitation Radar (PR-2) is currently being developed by the National Aeronautics and Space Administration Jet Propulsion Laboratory to support the development of future spaceborne radar missions. PR-2 will rely on high-performance onboard processing techniques in order to improve the observation capabilities (swath width, spatial resolution, and precision) of a low-earth orbiting rainfall radar. Using field-programmable gate arrays (FPGAs), we have developed a prototype spaceborne processor and controller module that will support advanced capabilities in the PR-2 such as autotargeting of rain and compression of rainfall science data. In this paper, we describe the new technology components designed for the onboard processor, including an FPGA-based 40 x 10(9) op/s pulse-compression receiver/filter with a range sidelobe performance of -72 dB, and an adaptive scanning controller which yields a six-fold increase in the number of radar looks over areas of precipitation. C1 CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, Pasadena, CA 91109 USA. Andraka Consulting Grp Inc, North Kingstown, RI 02852 USA. RP Fischman, MA (reprint author), CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mafisch@mail1.jpl.nasa.gov; ray@andraka.com NR 17 TC 10 Z9 12 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD APR PY 2005 VL 43 IS 4 BP 802 EP 812 DI 10.1109/TGRS.2005.844670 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 909TB UT WOS:000227882500013 ER PT J AU Brennan, JI Kaufman, YJ Koren, I Li, RR AF Brennan, JI Kaufman, YJ Koren, I Li, RR TI Aerosol-cloud interaction-misclassification of MODIS clouds in heavy aerosol SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosols; clouds; Moderate Resolution Imaging Spectroradiometer (MODIS); remote sensing ID CLIMATE AB The accuracy of the spaceborne Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask was evaluated for possible contamination by areas of heavy aerosol that may be misclassified as clouds. Analysis for several aerosol types shows that the cloud mask and products can be safely used in the presence of aerosol up to optical thickness of 0.6. Here we define as cloudy all MODIS 1-km (at nadir) pixels that were used to derive the cloud effective radius and optical thickness of water and ice clouds. The findings make it possible to study aerosol-cloud interaction from the MODIS aerosol and cloud products. C1 NASA, Goddard Space Flight Ctr, Summer Inst Atmospher Hydrospher & Terr Sci, Greenbelt, MD 20771 USA. Penn State Univ, University Pk, PA 16802 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Brennan, JI (reprint author), NASA, Goddard Space Flight Ctr, Summer Inst Atmospher Hydrospher & Terr Sci, Greenbelt, MD 20771 USA. RI Koren, Ilan/K-1417-2012 OI Koren, Ilan/0000-0001-6759-6265 NR 7 TC 43 Z9 43 U1 0 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD APR PY 2005 VL 43 IS 4 BP 911 EP 915 DI 10.1109/TGRS.2005.844662 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 909TB UT WOS:000227882500024 ER PT J AU Li, LF Jindal, N Goldsmith, A AF Li, LF Jindal, N Goldsmith, A TI Outage capacities and optimal power allocation for fading multiple-access channels SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article; Proceedings Paper CT IEEE International Symposium on Information Theory (ISIT 2000) CY JUN, 2000 CL SORRENTO, ITALY SP IEEE DE capacity region; fading channels; multiple-access channels (MACs); optimal power allocation; outage probability ID OPTIMAL RESOURCE-ALLOCATION; BROADCAST CHANNELS; PART II AB We derive the outage capacity region of an M-user fading multiple-access channel (MAC) under the assumption that both the transmitters and the receiver have perfect channel side information (CSI). The outage capacity region is implicitly obtained by deriving the outage probability region for a given rate vector. Given a required rate and average power constraint for each user, we find a successive decoding strategy and a power allocation policy that achieves points on the boundary of the outage probability region. We discuss the scenario where an outage must be declared simultaneously for all users (common outage) and when outages can be declared individually (individual outage) for each user. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Minnesota, Minneapolis, MN 55455 USA. Stanford Univ, Stanford, CA 94305 USA. RP Li, LF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lifang@systems.caltech.edu; nihar@ece.umn.edu; andrea@ee.stanford.edu NR 18 TC 54 Z9 55 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD APR PY 2005 VL 51 IS 4 BP 1326 EP 1347 DI 10.1109/TIT.2005.844065 PG 22 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 912AZ UT WOS:000228050800005 ER PT J AU Bautz, M Prigozhin, G Kissel, S LaMarr, B Grant, C Brown, S AF Bautz, M Prigozhin, G Kissel, S LaMarr, B Grant, C Brown, S TI Anomalous annealing of a high-resistivity CCD irradiated at low temperature SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE charge-coupled device (CCD); electron traps; interstitial carbon; radiation damage; X-ray ID INTERSTITIAL-CARBON; SILICON DETECTORS; RADIATION AB The front-illuminated charge-coupled device (CCD) detectors in the Chandra X-ray Observatory's ACIS instrument suffered radiation damage from soft protons focused by the telescope mirror early in the mission. In the course of assessing this damage, the focal plane was temporarily warmed from its normal operating temperature (then -100 degrees C) to +30 degrees C. Following this "bakeout," the radiation-damaged CCDs exhibited significantly greater charge transfer inefficiency (CTI). We performed a laboratory experiment with a sibling of the flight detectors in an attempt to reproduce and better understand this phenomenon. The test CCD was cooled to -100 degrees C, irradiated by 120 keV protons and then warmed to +30 degrees C for 8 hours. As expected, after the initial irradiation, but before detector warmup, a substantial CTI increase was observed. The subsequent warmup itself then produced an additional factor approximate to 2.5 increase in CTI. Following smaller subsequent irradiations with the detector cold, a "bakeout" for 8 hours at -60 degrees C produced no observable increase in CTI. However, a subsequent bakeout to +30 degrees C for another 8 hours resulted in an additional increase in CTI of roughly 15%. The CTI changes produced by the room temperature bakeout are accompanied by dramatic changes in the de-trapping times of electron traps responsible for the CTI. The distributions of signal amplitudes in the pixels trailing X-ray events indicate that annealing at room temperature can cause large changes of the trap emission times, from which we infer that conversion of trapping defects takes place. The observed phenomena can be explained by the previously suggested mechanism of carbon-related defect transformation. Specifically, the room-temperature annealing may allow carbon interstitials to form metastable complexes with phosphorus and/or carbon substitutional atoms. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP MIT, Ctr Space Res, Cambridge, MA 02139 USA. EM mwb@space.mit.edu NR 18 TC 13 Z9 13 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD APR PY 2005 VL 52 IS 2 BP 519 EP 526 DI 10.1109/TNS.2005.846873 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 916EF UT WOS:000228367500003 ER PT J AU Bose, D Govindan, TR AF Bose, D Govindan, TR TI Wave currents in a helicon plasma source-model results SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE Helicon plasma; plasma sources; radio frequency (RF) plasma AB The propagation of wave components of plasma current in a helicon source is shown. The simulation results are obtained by self-consistently solving the wave equations with the discharge balance equations in a two-dimensional axisymmetric plasma reactor. The space charge wave is also included to model the Trivelpiece-Gould wave mode. C1 NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. RP Bose, D (reprint author), NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. EM dbose@arc.nasa.gov NR 2 TC 0 Z9 0 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 2005 VL 33 IS 2 BP 374 EP 375 DI 10.1109/TPS.2005.845306 PN 1 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 916ST UT WOS:000228407100076 ER PT J AU Markusic, TE Berkery, JW Choueiri, EY AF Markusic, TE Berkery, JW Choueiri, EY TI Visualization of current sheet evolution in a pulsed plasma accelerator SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE current density; magnetic field measurement; photography; plasma engines; plasma sheaths; visualization AB High-speed photography and magnetic field probes were used to visualize and study the formation and propagation of current sheets in a pulsed plasma accelerator. Magnetic field measurements complement photographic records, as the latter indicate the location of the plasma but not necessarily current, whereas magnetic field data provide an unambiguous picture of the current location, but do not directly yield the location of the plasma. The observed current sheet evolution was found to be rich in features and has produced fundamental insight into the phenomena of current sheet canting and trailing wake formation. C1 NASA, Martin Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35810 USA. Princeton Univ, Dept Mech & Aerosp Engn, Elect Propuls & Plasma Dynam Lab, Princeton, NJ 08544 USA. RP Markusic, TE (reprint author), NASA, Martin Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35810 USA. EM markusic@msfc.nasa.gov; choueiri@princeton.edu RI Berkery, John/B-7930-2011 NR 6 TC 4 Z9 4 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 2005 VL 33 IS 2 BP 528 EP 529 DI 10.1109/TPS.2005.845898 PN 1 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 916ST UT WOS:000228407100153 ER PT J AU Remy, J Biennier, L Salama, F AF Remy, J Biennier, L Salama, F TI Plasma in a pulsed discharge environment SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE glow discharge; plasma; polycyclic aromatic hydrocarbon (PAH); pulsed discharge nozzle AB The plasma generated in a pulsed slit discharge nozzle is used to form molecular ions in an astrophysically relevant environment. The plasma has been characterized as a glow discharge in the abnormal regime. Laboratory studies help understand the formation processes of polycyclic aromatic hydrocarbon (PAH) ions that are thought to be the source of the ubiquitous unidentified infrared bands. C1 Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands. Univ Rennes 1, Lab Phys Atomes Lasers Mol & Surfaces, F-35042 Rennes, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Remy, J (reprint author), Eindhoven Univ Technol, Dept Appl Phys, POB 513, NL-5600 MB Eindhoven, Netherlands. RI Salama, Farid/A-8787-2009; Biennier, Ludovic/O-1618-2014 OI Salama, Farid/0000-0002-6064-4401; NR 4 TC 4 Z9 4 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 2005 VL 33 IS 2 BP 554 EP 555 DI 10.1109/TPS.2005.845937 PN 1 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 916ST UT WOS:000228407100166 ER PT J AU Osherovich, VA Benson, RF Fainberg, J AF Osherovich, VA Benson, RF Fainberg, J TI Electromagnetic bounded states and challenges of plasma spectroscopy SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 31st IEEE International Conference on Plasma Science (ICOPS 2004) CY JUN 28-JUL 01, 2004 CL Baltimore, MD SP IEEE DE cylindrical bounded states; eigenmode solutions; magnetized plasmas; nonlinear differential equations; plasma oscillations ID FREE MAGNETIC FIELDS; CYLINDRICAL OSCILLATIONS; RADIO EMISSIONS; PHYSICAL NATURE; RESONANCES; IONOSPHERE; WAVES; CLASSIFICATION; INSTABILITY; SPACECRAFT AB We review the foundations and observational support for a new plasma wave mode that has been proposed to explain emissions stimulated by satellite-born high-power radio-frequency sounders. These sounders, which are designed to derive remote electron density profiles from electromagnetic-wave echoes, stimulate plasma resonances in the local plasma. In addition to stimulating resonances at the electron plasma frequency f(pe), harmonics of electron gyrofrequency f(ce), and at the upper hybrid frequency f(uh), resonances are also stimulated at frequencies below f(pe) between the gyroharmonics. The first such resonance, with frequency between f(ce) and 2f(ce), was discovered by Nelms and Lockwood in 1967 using the topside sounder on Alouette 2. From its appearance, it was called a diffuse resonance (D-1 in modern notation) and was originally thought to have a frequency of 3/2f(ce). Further observations, and theoretical insights, indicated that f(D1) is dependent on f(pe) and f(ce), namely, f(D1) = (3/pi)(f(pe)f(ce))(1/2). The theoretical concepts used to obtain this expression indicated that the D-n resonances (n = 1, 2, 3....) are electron eigen-modes (electromagnetic bounded states) and led to equations describing the frequencies of the entire D-n sequence and their subsidiary resonances D-n(+) and D-n. Such formulas, based on a combined theoretical and empirical approach, describe a root n spectrum with the frequency of each mode split by the magnetic field analogous to the Zeeman splitting in quantum mechanics. The root n spectrum was first predicted for force-free electromagnetic cylindrical plasma oscillations by Osherovich in 1986. The main theoretical challenge remains to derive the frequency f(D1) from first principles. Although the D-n resonances have been stimulated in the terrestrial ionosphere for decades by topside sounder satellites such as Alouette 2 and by electron guns on several rocket experiments, and in Jupiter's Io plasma torus by the sounder on the Ulysses space probe, and are currently being stimulated in the terrestrial magnetosphere by the sounder on the IMAGE spacecraft, they have yet to be observed in laboratory experiments. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Osherovich, VA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM vladimir@urap.gsfc.nasa.gov; robert.f.benson@nasa.gov; joseph.fainberg@nasa.gov NR 39 TC 6 Z9 6 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 2005 VL 33 IS 2 BP 599 EP 608 DI 10.1109/TPS.2005.845255 PN 2 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 916SX UT WOS:000228407500003 ER PT J AU Yu, YH Chang, JT AF Yu, YH Chang, JT TI Shadow graphs and 3D texture reconstruction SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE 3D texture; surface geometry; shape-from-shadow; shadow graph; shading; photometric stereo; optimization ID REAL-WORLD SURFACES; REFLECTANCE; SHAPE; SEGMENTATION AB We present methods for recovering surface height fields such as geometric details of 3D textures by incorporating shadow constraints. We introduce shadow graphs which give a new graph-based representation for shadow constraints. It can be shown that the shadow graph alone is sufficient to solve the shape-from-shadow problem from a dense set of images. Shadow graphs provide a simpler and more systematic approach to represent and integrate shadow constraints from multiple images. To recover height fields from a sparse set of images, we propose a method for integrated shadow and shading constraints. Previous shape-from-shadow algorithms do not consider shading constraints while shape-from-shading usually assumes there is no shadow. Our method is based on collecting a set of images from a fixed viewpoint as a known light source changes its position. It first builds a shadow graph from shadow constraints from which an upper bound for each pixel can be derived if the height values of a small number of pixels are initialized correctly. Finally, a constrained optimization procedure is designed to make the results from shape-from-shading consistent with the height bounds derived from the shadow constraints. Our technique is demonstrated on both synthetic and real imagery. C1 Univ Illinois, Dept Comp Sci, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yu, YH (reprint author), Univ Illinois, Dept Comp Sci, 201 N Goodwin Ave, Urbana, IL 61801 USA. EM yyz@cs.uiuc.edu; johnny.t.chang@jpl.nasa.gov RI YU, YIZHOU/D-1603-2013 NR 36 TC 13 Z9 13 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-5691 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD APR-MAY PY 2005 VL 62 IS 1-2 BP 35 EP 60 PG 26 WC Computer Science, Artificial Intelligence SC Computer Science GA 866XV UT WOS:000224807600004 ER PT J AU Jongen, T Gatski, TB AF Jongen, T Gatski, TB TI Tensor representations and solutions of constitutive equations for viscoelastic fluids SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article ID HOMOGENEOUS TURBULENCE; FLOWS; CLASSIFICATION AB An approach is developed using tensor representations to assess and characterize both the transient behavior and equilibrium states of viscoelastic fluid constitutive equations in viscometric flows. The methodology is based on the replacement of the differential constitutive equation for the deviatoric part of the viscoelastic stress tensor by an equivalent and more tractable set of differential equations for the characteristic scalar invariants. In the case of planar flows, this equivalence leads to an explicit, closed-form analytic solution for the time evolution of the extra-stress tensor that is formally expressed as a second-order fluid relation, with time-dependent coefficients. As a validation of the approach, an analysis of the transient and equilibrium system characteristics of fluid flows described by the corotational Jeffreys model and general Oldroyd-type constitutive equations is presented. © 2005 Elsevier Ltd. All rights reserved. C1 Techsp Aero, Snecma Grp, B-4041 Herstal, Belgium. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Jongen, T (reprint author), Techsp Aero, Snecma Grp, Route Liers 121, B-4041 Herstal, Belgium. EM tjongen@techspace-acro.be NR 24 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD APR PY 2005 VL 43 IS 7 BP 556 EP 588 DI 10.1016/j.ijengsci.2004.10.003 PG 33 WC Engineering, Multidisciplinary SC Engineering GA 932AG UT WOS:000229526000002 ER PT J AU Emerson, CW Lam, NSN Quattrochi, DA AF Emerson, CW Lam, NSN Quattrochi, DA TI A comparison of local variance, fractal dimension, and Moran's I as aids to multispectral image classification SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID COOCCURRENCE MATRIX; SATELLITE DATA; SPOT IMAGERY; TEXTURE AB The accuracy of traditional multispectral maximum-likelihood image classification is limited by the multi-modal statistical distributions of digital numbers from the complex, heterogenous mixture of land cover types in urban areas. This work examines the utility of local variance, fractal dimension and Moran's I index of spatial autocorrelation in segmenting multispectral satellite imagery with the goal of improving urban land cover classification accuracy. Tools available in the ERDAS Imagine TM software package and the Image Characterization and Modeling System (ICAMS) were used to analyse Landsat ETM+ imagery of Atlanta, Georgia. Images were created from the ETM+ panchromatic band using the three texture indices. These texture images were added to the stack of multispectral bands and classified using a supervised, maximum likelihood technique. Although each texture band improved the classification accuracy over a multispectral only effort, the addition of fractal dimension measures is particularly effective at resolving land cover classes within urbanized areas, as compared to per-pixel spectral classification techniques. C1 Western Michigan Univ, Dept Geog, Kalamazoo, MI 49008 USA. Louisiana State Univ, Dept Geog & Anthropol, Baton Rouge, LA 70803 USA. NASA, George C Marshall Space Flight Ctr, Dept Earth Sci, Huntsville, AL 35812 USA. RP Emerson, CW (reprint author), Western Michigan Univ, Dept Geog, Kalamazoo, MI 49008 USA. EM charles.emerson@wmich.edu; nlam@lsu.edu; dale.quattrochi@nasa.gov NR 26 TC 38 Z9 41 U1 0 U2 19 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD APR PY 2005 VL 26 IS 8 BP 1575 EP 1588 DI 10.1080/01431160512331326765 PG 14 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 928JM UT WOS:000229267700003 ER PT J AU Bowles, KJ Papadopoulos, DS Scheiman, DA Inghram, LL McCorkle, LS Klans, OV AF Bowles, KJ Papadopoulos, DS Scheiman, DA Inghram, LL McCorkle, LS Klans, OV TI Cursory examination of the thermal degradation mechanisms of six high-temperature composite matrices SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID PMR-15 RESIN AB Studies were conducted with six different candidate high-temperature neat matrix resin specimens of varied geometric shapes to investigate the mechanisms involved in the thermal degradation of polyimides like PMR-15. The metrics for assessing the quality of these candidates were chosen to be glass transition temperature (T), thermo-oxidative stability, dynamic mechanical properties, microstructural changes, and dimensional stability. The processing and mechanical properties were not investigated in the study reported herein. The dimensional changes and surface layer growth were measured and recorded. The data were in agreement with earlier published data. An initial weight increase reaction was observed to be dominating at the lower temperatures. However, at the more elevated temperatures, the weight loss reactions were prevalent and probably masked the weight gain reaction. These data confirmed the findings of the existence of an initial weight gain reaction previously reported(1-10). Surface- and core-dependent weight losses were shown to control the polymer degradation at the higher temperatures. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Akron, Akron, OH 44325 USA. QSS Grp Inc, Cleveland, OH USA. Ohio Aerosp Inst, Brookpark, OH USA. RP Bowles, KJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER-COVINA JI J. Adv. Mater. PD APR PY 2005 VL 37 IS 2 BP 30 EP 43 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 004BY UT WOS:000234728200006 ER PT J AU Fragomeni, JM Nunes, AC AF Fragomeni, JM Nunes, AC TI The study of the effects of the parameters of welding on electron beam welding performed in the microgravity space environment SO JOURNAL OF ADVANCED MATERIALS LA English DT Article AB This study was undertaken in order to be sure that no hazard would exist from impingement of hot molten metal particle detachments upon an astronauts' space suit during any future electron beam welding exercises or experiments. The conditions under which molten metal detachments might occur in a space welding environment ;were analyzed. The safety issue is important during welding with regard to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises in microgravity at Low Earth Orbit. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. A weld pool detachment parameter for specifying the conditions for metal weld pool detachment by impact was derived and correlated to the experimental results. The experimental results were for the most part consistent with the theoretical analysis and predictions. C1 Univ Detroit, Dept Mech Engn, Coll Engn & Sci, Detroit, MI 48221 USA. NASA, George C Marshall Space Flight Ctr, Mat Proc & Mfg Dept, Huntsville, AL 35812 USA. RP Fragomeni, JM (reprint author), Univ Detroit, Dept Mech Engn, Coll Engn & Sci, Detroit, MI 48221 USA. NR 9 TC 0 Z9 0 U1 1 U2 11 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER-COVINA JI J. Adv. Mater. PD APR PY 2005 VL 37 IS 2 BP 44 EP 55 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 004BY UT WOS:000234728200007 ER PT J AU Yuter, SE Houze, RA Smith, EA Wilheit, TT Zipser, E AF Yuter, SE Houze, RA Smith, EA Wilheit, TT Zipser, E TI Physical characterization of tropical oceanic convection observed in KWAJEX SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TRMM PRECIPITATION RADAR; MULTIPLE MICROWAVE-FREQUENCIES; MEASURING MISSION TRMM; PACIFIC WARM POOL; RAINDROP SIZE DISTRIBUTIONS; MONSOON CLOUD CLUSTERS; TOGA COARE; RADIATIVE-TRANSFER; WESTERN PACIFIC; SATELLITE MEASUREMENTS AB The Tropical Rainfall Measuring Mission (TRMM) Kwajalein Experiment (KWAJEX) was designed to obtain an empirical physical characterization of precipitating convective clouds over the tropical ocean. Coordinated datasets were collected by three aircraft, one ship, five upper-air sounding sites, and a variety of continuously recording remote and in situ surface-based sensors, including scanning Doppler radars, profilers, disdrometers, and rain gauges. This paper describes the physical characterization of the Kwajalein cloud population that has emerged from analyses of datasets that were obtained during KWAJEX and combined with long-term TRMM ground validation site observations encompassing three rainy seasons. The spatial and temporal dimensions of the precipitation entities exhibit a lognormal probability distribution. as has been observed over other parts of the tropical ocean. The diurnal cycle of the convection is also generally similar to that seen over other tropical oceans. The largest precipitating cloud elements-those with rain areas exceeding 14 000 km(2)-have the most pronounced diurnal cycle, with a maximum frequency of occurrence before dawn; the smallest rain areas are most frequent in the afternoon. The large systems exhibited stratiform rain areas juxtaposed with convective regions. Frequency distributions of dual-Doppler radar data showed narrow versus broad spectra of divergence in the stratiform and convective regions, respectively, as expected because strong up- and downdrafts are absent in the stratiform regions. The dual-Doppler profiles consistently showed low-level convergence and upper-level divergence in convective regions and midlevel convergence sandwiched between lower- and upper-level divergence in stratiform regions. However, the magnitudes of divergence are sensitive to assumptions made in classifying the radar echoes as convective or stratiform. This sensitivity implies that heating profiles derived from satellite radar data will be sensitive to the details of the scheme used to separate convective and stratiform rain areas. Comparison of airborne passive microwave data with round-based radar data indicates that the pattern of scattering of 85-GHz radiance by ice particles in the upper portions of KWAJEX precipitating clouds is poorly correlated with the precipitation pattern at lower levels while the emission channels (10 and 19 GHz) have brightness temperature patterns that closely correspond to the lower-level precipitation structure. In situ ice particle imagery obtained by aircraft at upper levels (similar to 11 km) shows that the concentrations of ice particles of all densities are greater in the upper portions of active convective rain regions and lower in the upper portions of stratiform regions, probably because the active updrafts convey the particles to upper levels, whereas in the stratiform regions sedimentation removes the larger ice particles over time. Low-level aircraft flying in the rain layer show similar total drop concentrations in and out of convective cells, but they also show a sudden jump in the concentration of larger raindrops at the boundaries of the cells, indicating a discontinuity in growth processes such as coalescence at the cell boundary. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Texas A&M Univ, Dept Meteorol, College Stn, TX 77843 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. RP Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. EM yuter@atmos.washington.edu RI Wilheit, Thomas/G-9438-2012; Yuter, Sandra/E-8808-2015 OI Yuter, Sandra/0000-0002-3222-053X NR 84 TC 55 Z9 59 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 2005 VL 44 IS 4 BP 385 EP 415 DI 10.1175/JAM2206.1 PG 31 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 924JP UT WOS:000228975400001 ER PT J AU Racette, PE Westwater, ER Han, Y Gasiewski, AJ Klein, M Cimini, D Jones, DC Manning, W Kim, EJ Wang, JR Leuski, V Kiedron, P AF Racette, PE Westwater, ER Han, Y Gasiewski, AJ Klein, M Cimini, D Jones, DC Manning, W Kim, EJ Wang, JR Leuski, V Kiedron, P TI Measurement of low amounts of precipitable water vapor using ground-based millimeterwave radiometry SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MICROWAVE RADIOMETERS; IMAGING RADIOMETER; CLOUD LIQUID; RAMAN LIDAR; RETRIEVAL; RADIOSONDE; HUMIDITY; TEMPERATURE; CALIBRATION; TROPOSPHERE AB Extremely dry conditions characterized by amounts of precipitable water vapor (PWV) as low as 1-2 turn commonly occur in high-latitude regions during the winter months. While such dry atmospheres carry only a few percent of the latent heat energy compared to tropical atmospheres, the effects of low vapor amounts on the polar radiation budget-both directly through modulation of longwave radiation and indirectly through the formation of clouds-are considerable. Accurate measurements of PWV during such dry conditions are needed to improve polar radiation models for use in understanding and predicting change in the climatically sensitive polar regions. To this end, the strong water-vapor absorption line at 183.310 GHz provides a unique means of measuring low amounts of PWV. Weighting function analysis, forward model calculations based upon a 7-yr radiosonde dataset, and retrieval simulations consistently predict that radiometric measurements made using several milliimeter-wavelength (MMW) channels near the 183-GHz line, together with established microwave (MW) measurements near the 22.235-GHz water-vapor line and similar to 31-GHz atmospheric absorption window can be used to determine within 5% uncertainty the full range of PWV expected in the Arctic. This combined capability stands in spite of accuracy limitations stemming from uncertainties due to the sensitivity of the vertical distribution of temperature and water vapor at MMW channels. In this study the potential of MMW radiornetry using the 183-GHz line for measuring low amounts of PWV is demonstrated both theoretically and experimentally. The study uses data obtained during March 1999 as part of an experiment conducted at the Department of Energy's Cloud and Radiation Testbed (CART) site near Barrow, Alaska. Several radiometers from both NOAA and NASA were deployed during the experiment to provide the first combined MMW and MW ground-based dataset during dry Arctic conditions. Single-channel retrievals of PWV were performed using the MW and MMW data. Discrepancies in the retrieved values were found to be consistent with differences observed between measured brightness temperatures (TBs) and forward-niodeled TBs based on concurrent radiosonde profiles. These discrepancies are greater than can be explained by radiometer measurement error alone; errors in the absorption models and uncertainty in the radiosonde measurements contribute to the discrepancies observed. The measurements, retrieval technique, and line model discrepancies are discussed, along with difficulties and potential of MMW/MW PWV measurement. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80309 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Silver Spring, MD USA. Univ Aquila, CETEMPS, I-67100 Laquila, Italy. Met Off, Exeter, Devon, England. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. SUNY Albany, Univ Albany, Atmospher Sci Res Ctr, Albany, NY 12222 USA. RP Racette, PE (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 555, Greenbelt, MD 20771 USA. EM Paul.E.Racette@nasa.gov RI Han, Yong/F-5590-2010; Cimini, Domenico/M-8707-2013 OI Han, Yong/0000-0002-0183-7270; Cimini, Domenico/0000-0002-5962-223X NR 55 TC 31 Z9 31 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2005 VL 22 IS 4 BP 317 EP 337 DI 10.1175/JTECH1711.1 PG 21 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 928QU UT WOS:000229287600001 ER PT J AU Loeb, NG Kato, S Loukachine, K Manalo-Smith, N AF Loeb, NG Kato, S Loukachine, K Manalo-Smith, N TI Angular distribution models for top-of-atmosphere radiative flux estimation from the Clouds and the Earth's Radiant Energy System instrument on the Terra satellite. Part I: Methodology SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MEASURING MISSION SATELLITE; BIDIRECTIONAL REFLECTANCE; CIRRUS CLOUDS; VALIDATION; ALGORITHM; CERES; RETRIEVAL; PACKAGE; BUDGET; MODIS AB The Clouds and Earth's Radiant Energy System (CERES) provides coincident global cloud and aerosol properties together with reflected solar, emitted terrestrial longwave, and infrared window radiative fluxes. These data are needed to improve the understanding and modeling of the interaction between clouds, aerosols, and radiation at the top of the atmosphere, surface, and within the atmosphere. This paper describes the approach used to estimate top-of-atmosphere (TOA) radiative fluxes from instantaneous CERES radiance measurements on the Terra satellite. A key component involves the development of empirical angular distribution models (ADMs) that account for the angular dependence of the earth's radiation field at the TOA. The CERES Terra ADMs are developed using 24 months of CERES radiances, coincident cloud and aerosol retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from the Global Modeling and Assimilation Office (GMAO)'s Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) V4.0.3 product. Scene information for the ADMs is from MODIS retrievals and GEOS DAS V4.0.3 properties over the ocean, land, desert, and snow for both clear and cloudy conditions. Because the CERES Terra ADMs are global, and far more CERES data are available on Terra than were available from CERES on the Tropical Rainfall Measuring Mission (TRMM), the methodology used to define CERES Terra ADMs is different in many respects from that used to develop CERES TRMM ADMs, particularly over snow/sea ice, under cloudy conditions, and for clear scenes over land and desert. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Sci Applicat Int Corp, Hampton, VA USA. Analyt Serv & Mat, Hampton, VA USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM n.g.loeb@larc.nasa.gov NR 40 TC 159 Z9 160 U1 2 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2005 VL 22 IS 4 BP 338 EP 351 DI 10.1175/JTECH1712.1 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 928QU UT WOS:000229287600002 ER PT J AU Wolff, DB Marks, DA Amitai, E Silberstein, DS Fisher, BL Tokay, A Wang, J Pippitt, JL AF Wolff, DB Marks, DA Amitai, E Silberstein, DS Fisher, BL Tokay, A Wang, J Pippitt, JL TI Ground Validation for the Tropical Rainfall Measuring Mission (TRMM) SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RADAR REFLECTIVITY; CONVECTION AB An overview of the Tropical Rainfall Measuring Mission (TRMM) Ground Validation (GV) Program is presented. This ground validation (GV) program is based at NASA Goddard Space Flight Center in Greenbelt, Maryland, and is responsible for processing several TRMM science products for validating space-based rain estimates from the TRMM satellite. These products include gauge rain rates, and radar-estimated rain intensities, type, and accumulations, from four primary validation sites (Kwajalein Atoll, Republic of the Marshall Islands; Melbourne, Florida; Houston, Texas; and Darwin, Australia). Site descriptions of rain gauge networks and operational weather radar configurations are presented together with the unique processing methodologies employed within the Ground Validation System (GVS) software packages. Rainfall intensity estimates are derived using the Window Probability Matching Method (WPMM) and then integrated over specified time scales. Error statistics from both dependent and independent validation techniques show good agreement between gauge-measured and radar-estimated rainfall. A comparison of the NASA GV products and those developed independently by the University of Washington for a subset of data from the Kwajalein Atoll site also shows good agreement. A comparison of NASA GV rain intensities to satellite retrievals from the TRMM Microwave Imager (TMI), precipitation radar (PR), and Combined (COM) algorithms is presented, and it is shown that the GV and satellite estimates agree quite well over the open ocean. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Wolff, DB (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912-1, Greenbelt, MD 20771 USA. EM wolff@radar.gsfc.nasa.gov NR 31 TC 92 Z9 98 U1 1 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2005 VL 22 IS 4 BP 365 EP 380 DI 10.1175/JTECH1700.1 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 928QU UT WOS:000229287600004 ER PT J AU Seevaratnam, GK Walker, LM Rame, E Garoff, S AF Seevaratnam, GK Walker, LM Rame, E Garoff, S TI Wetting by simple room-temperature polymer melts: deviations from Newtonian behavior SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE non-Newtonian; polymer melts; dynamic wetting; contact angle ID MOVING CONTACT LINES; BOUNDARY-CONDITIONS; LIQUIDS; ANGLES; FLOW; HYDRODYNAMICS; INTERFACE; DYNAMICS AB The hydrodynamics near moving contact lines of two room-temperature polymer melts, polyisobutylene (PIB) and polystyrene (PS), are different from those of a third polymer melt, polydimethylsiloxane (PDMS). While all three fluids exhibit Newtonian behavior in rotational theological measurements, a model of the hydrodynamics near moving contact lines which assumes Newtonian behavior of the fluid accurately describes the interface shape of a variety of PDMS fluids but fails to describe the interface deformation by viscous forces in PIB and PS. The magnitude of the deviations from the model and the distance along the liquid-vapor interface over which they are seen increase with increasing capillary number. We conclude that the wetting behaviors of PIB and PS are influenced by weak elasticity in these low molecular weight melts and that dynamic wetting is more sensitive to this elasticity than standard rheometric techniques. (c) 2004 Published by Elsevier Inc. C1 Carnegie Mellon Univ, Dept Chem Engn, Pittsburgh, PA 15213 USA. Carnegie Mellon Univ, Ctr Complex Fluids Engn, Pittsburgh, PA 15213 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. NASA Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Garoff, S (reprint author), Carnegie Mellon Univ, Ctr Complex Fluids Engn, Pittsburgh, PA 15213 USA. EM sg2e@andrew.cmu.edu RI Garoff, Stephen/P-7629-2014; Walker, Lynn/I-2562-2016 OI Garoff, Stephen/0000-0001-8148-8535; Walker, Lynn/0000-0002-7478-9759 NR 26 TC 10 Z9 10 U1 0 U2 13 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD APR 1 PY 2005 VL 284 IS 1 BP 265 EP 270 DI 10.1016/j.jcis.2004.09.056 PG 6 WC Chemistry, Physical SC Chemistry GA 908WA UT WOS:000227819700036 PM 15752812 ER PT J AU Strigari, LE Beacom, JF Walker, TP Zhang, P AF Strigari, LE Beacom, JF Walker, TP Zhang, P TI The concordance cosmic star formation rate: implications from and for the supernova neutrino and gamma ray backgrounds SO JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS LA English DT Review DE supernova neutrinos; neutrino and gamma astronomy; cosmological neutrinos; star formation ID GALAXY REDSHIFT SURVEY; LYMAN BREAK GALAXIES; FORMATION HISTORY; LUMINOSITY FUNCTIONS; RELIC NEUTRINOS; DARK-MATTER; DEEP FIELDS; X-RAY; IA; CONSTRAINTS AB We constrain the cosmic star formation rate (CSFR) by requiring that massive stars produce the observed UV, optical, and IR light and at the same time not overproduce the diffuse supernova neutrino background as bounded by Super-Kamiokande. With the massive star component so constrained we then show that a reasonable choice of stellar initial mass function and other parameters results in SNIa rates and iron yields in good agreement with data. In this way we define a 'concordance' CSFR that predicts the optical SNII rate and the SNIa contribution to the MeV cosmic gamma ray background. The CSFR constrained to reproduce these and other proxies of intermediate and massive star formation is more clearly delineated than if it were measured by any one technique and has the following testable consequences: ( 1) SNIa contribute only a small fraction of the MeV cosmic gamma ray background, ( 2) massive star core collapse is nearly always accompanied by a successful optical SNII, and ( 3) the diffuse supernova neutrino background is tantalizingly close to detectability. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Strigari, LE (reprint author), Ohio State Univ, Dept Phys, 174 W 18th Ave, Columbus, OH 43210 USA. EM strigari@mps.ohio-state.edu; beacom@mps.ohio-state.edu; twalker@mps.ohio-state.edu; zhangpj@fnal.gov RI ZHANG, PENGJIE/O-2825-2015; OI Strigari, Louis/0000-0001-5672-6079; Beacom, John/0000-0002-0005-2631 NR 101 TC 59 Z9 59 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1475-7516 J9 J COSMOL ASTROPART P JI J. Cosmol. Astropart. Phys. PD APR PY 2005 IS 4 AR 017 DI 10.1088/1475-7516/2005/04/017 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 923TP UT WOS:000228932500002 ER PT J AU Kassemi, M Barsi, S Alexander, JID Banish, M AF Kassemi, M Barsi, S Alexander, JID Banish, M TI Contamination of microgravity liquid diffusivity measurements by void-generated thermocapillary convection SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE bubbles; marangoni convention; numerical models; self-diffusion measurement; thermocapillary flow; voids; microgravity conditions ID SELF-DIFFUSION; MERCURY; SOLIDIFICATION; INSENSITIVITY; SEGREGATION; BUBBLE AB This paper examines the effects of thermocapillary convection generated by a void or bubble on the self-diffusion measurement of molten indium in microgravity. The study is based on the thermophysical and geometrical configurations of the self-diffusion in liquid elements (SIDLE) microgravity experiment. A transient finite element model of the diffusion capillary is presented. Numerical simulations of the transport processes in the diffusion capillary indicate that the concentration stratification in the enclosure is greatly modified by void-generated convection when small temperature non-uniformities are present in the system. The extent to which this modification can contaminate the diffusion data obtained by the Harned-Codastefano methodology is determined. In order to generalize the findings, results are summarized by relating the extent of the convective contamination of the diffusion data to the thermocapillary Reynolds number of the bubble and the Schmidt number of the system. (c) 2004 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mech Engn, Cleveland, OH 44106 USA. Univ Alabama, Ctr Micrograv & Mat Res, Huntsville, AL 36899 USA. RP Kassemi, M (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, 21000 Brookpk Rd,MS110-3, Cleveland, OH 44135 USA. EM Mohammad.Kassemi@grc.nasa.gov NR 34 TC 8 Z9 9 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR 1 PY 2005 VL 276 IS 3-4 BP 621 EP 634 DI 10.1016/j.jcrysgro.2004.11.426 PG 14 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 916LB UT WOS:000228385300040 ER PT J AU Simon, D Simon, DL AF Simon, D Simon, DL TI Aircraft turbofan engine health estimation using constrained Kalman filtering SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 49th Gas Turbine Conference (TURBO EXPO 04) CY JUN 14-17, 2004 CL Vienna, AUSTRIA AB Kalman filters are often used to estimate the state variables of a dynamic system. However in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state-variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter This paper develops an analytic method of incorporating state-variable inequality constraints in the Kalman filter. The resultant filter is a combination of a standard Kalman filter and a quadratic programming problem. The incorporation of state-variable constraints increases the computational effort of the filter but significantly improves its estimation accuracy. The improvement is proven theoretically and shown via simulation results obtained from application to a turbofan engine model. This model contains 16 state variables, 12 measurements, and 8 component health parameters. It is shown that the new algorithms provide improved performance in this example over unconstrained Kalman filtering. C1 Cleveland State Univ, Dept Elect Engn, Cleveland, OH 44115 USA. NASA, Glenn Res Ctr, USA, Res Lab, Cleveland, OH 44138 USA. RP Simon, D (reprint author), Cleveland State Univ, Dept Elect Engn, 1960 E 24th St, Cleveland, OH 44115 USA. EM d.j.simon@csuohio.edu; donald.l.simon@grc.nasa.gov NR 20 TC 28 Z9 28 U1 1 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD APR PY 2005 VL 127 IS 2 BP 323 EP 328 DI 10.1115/1.1789153 PG 6 WC Engineering, Mechanical SC Engineering GA 926YZ UT WOS:000229160900013 ER PT J AU Provenza, AJ Montague, GT Jansen, MJ Palazzolo, AB Jansen, RH AF Provenza, AJ Montague, GT Jansen, MJ Palazzolo, AB Jansen, RH TI High temperature characterization of a radial magnetic bearing for turbomachinery SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 49th Gas Turbine Conference (TURBO EXPO 04) CY JUN 14-17, 2004 CL Vienna, AUSTRIA AB Open loop, experimental force and power measurements of a radial, redundant-axis, magnetic bearing at temperatures to 1000&DEG; F (538&DEG; C) and rotor speeds to 15,000 rpm along with theoretical temperature and force models are presented in this paper The experimentally measured force produced by a single C-core circuit using 22A was 600 lb (2.67 kN) at room temperature and 380 lb (1.69 kN) at 538&DEG; C. These values were compared withforce predictions based on a one-dimensional magnetic circuit analysis and a thermal analysis of gap growth as a function of temperature. The analysis showed that the reduction of force at high temperature is mostly due to an increase in radial gap due to test conditions, rather than to reduced core permeability. Tests under rotating conditions showed that rotor speed has a negligible effect on the bearing's static force capacity. One C-core required approximately 340 W of power to generate 190 lb (845 N) of magnetic force at 538&DEG; C, however the magnetic air gap was much larger than at room temperature. The data presented are after bearing operation for eleven total hours at 538&DEG; C and six thermal cycles. C1 USA, Res Lab, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Toledo, Toledo, OH 43606 USA. Texas A&M Univ, Dept Mech Engn, College Stn, TX USA. RP Provenza, AJ (reprint author), USA, Res Lab, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM andrew.j.provenza@nasa.gov; gerald.t.montague@nasa.gov; mark.j.jansen@nasa.gov; a-palazzolo@tamu.edu; ralph.h.jansen@nasa.gov NR 13 TC 5 Z9 6 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD APR PY 2005 VL 127 IS 2 BP 437 EP 444 DI 10.1115/1.1807413 PG 8 WC Engineering, Mechanical SC Engineering GA 926YZ UT WOS:000229160900027 ER PT J AU Limvoranusorn, P Cooper, CD Dietz, JD Clausen, CA Pettey, L Collins, MM AF Limvoranusorn, P Cooper, CD Dietz, JD Clausen, CA Pettey, L Collins, MM TI Kinetic modeling of the gas-phase oxidation of nitric oxide using hydrogen peroxide SO JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE LA English DT Article ID HIGH-PRESSURE; COMBUSTION; NO AB The use of hydrogen peroxide (H2O2) to enhance the oxidation of nitric oxide (NO) under postflame conditions in the presence or absence of sulfur dioxide (SO2) has been studied by means of chemical kinetic modeling and compared with pilot-scale experimental data. The experimental results were obtained from a nonisothermal reactor at atmospheric pressure with inlet temperatures in the range of 770-790 K. The CHEMKIN-II model with a kinetic mechanism from the literature was employed for this work. At the temperatures studied, H2O2 produces OH and HO2 radicals which enhance the oxidation of NO. The OH radical also helps oxidize SO2. The modeling results confirmed an optimum temperature of about 775 K where the NO conversion reached about 90% with an H2O2: NO molar ratio of 1:1. Conversion of NO2 to HNO3 was found to occur to a slight extent. Finally, the presence of SO2 was found to promote slightly the oxidation of NO to NO2. C1 Univ Cent Florida, Dept Civil & Environm Engn, Orlando, FL 32816 USA. Minist Nat Resources & Environm, Air Qual & Noise Management Bur, Bangkok, Thailand. Univ Cent Florida, Dept Chem, Orlando, FL 32816 USA. NASA, Kennedy Space Ctr, Cape Canaveral, FL 32898 USA. RP Cooper, CD (reprint author), Univ Cent Florida, Dept Civil & Environm Engn, 4000 Cent Florida Blvd, Orlando, FL 32816 USA. EM cooper@mail.ucf.edu NR 21 TC 4 Z9 5 U1 3 U2 14 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0733-9372 J9 J ENVIRON ENG-ASCE JI J. Environ. Eng.-ASCE PD APR PY 2005 VL 131 IS 4 BP 518 EP 525 DI 10.1061/(ASCE)0733-9372(2005)131:4(518) PG 8 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 907VI UT WOS:000227745700005 ER PT J AU Lien, MC Ruthruff, E Remington, RW Johnston, JC AF Lien, MC Ruthruff, E Remington, RW Johnston, JC TI On the limits of advance preparation for a task switch: Do people prepare all the task some of the time or some of the task all the time? SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID SIMPLE COGNITIVE TASKS; SPEEDED-CHOICE TASKS; BACKWARD INHIBITION; EXECUTIVE CONTROL; TERM-MEMORY; SET; REPETITION; COSTS; RECONFIGURATION; ATTENTION AB This study investigated the nature of advance preparation for a task switch, testing 2 key assumptions of R. De Jong's (2000) failure-to-engage theory: (a) Task-switch preparation is all-or-none, and (b) preparation failures stem from nonutilization of available control capabilities. In 3 experiments, switch costs varied dramatically across individual stimulus-response (S-R) pairs of the tasks-virtually absent for 1 pair but large for others. These findings indicate that, across trials, task preparation was not all-or-none but, rather, consistently partial (full preparation for some S-R pairs but not others). In other words, people do not prepare all of the task some of the time, they prepare some of the task all of the time. Experiments 2 and 3 produced substantial switch costs even though time deadlines provided strong incentives for optimal advance preparation. Thus, there was no evidence that people have a latent capability to fully prepare for a task switch. C1 Oregon State Univ, Dept Psychol, Corvallis, OR 97331 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lien, MC (reprint author), Oregon State Univ, Dept Psychol, Corvallis, OR 97331 USA. EM mei.lien@oregonstate.edu NR 39 TC 52 Z9 52 U1 1 U2 4 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0096-1523 EI 1939-1277 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD APR PY 2005 VL 31 IS 2 BP 299 EP 315 DI 10.1037/0096-1523.31.2.299 PG 17 WC Psychology; Psychology, Experimental SC Psychology GA 918SV UT WOS:000228568800006 PM 15826232 ER PT J AU Chao, BF AF Chao, BF TI On inversion for mass distribution from global (time-variable) gravity field SO JOURNAL OF GEODYNAMICS LA English DT Article DE inverse problem; solution uniqueness; gravity; time-variable gravity; spherical harmonics ID GRAVITATIONAL-FIELD; EARTHS ROTATION AB The well-known non-uniqueness of the gravitational inverse problem states that the external gravity field, even if completely and exactly known, cannot uniquely determine the density distribution of the body that produces the gravity field. In this paper, we provide conceptual insight by examining the problem in terms of spherical harmonic expansion of the global gravity field. By comparing the multipoles and the moments of the density function, we show that in 3-D the degree of knowledge deficiency in trying to inversely recover the density distribution from an external gravity field solution is (n + 1)(n + 2)/2 - (2n + 1) = n(n - 1)/2 for each harmonic degree n. On the other hand, on a 2-D spherical shell we show via a simple relationship that the inverse solution of the surface density distribution is unique. The latter applies quite readily in the inversion of time-variable gravity signals (such as those observed by the GRACE space mission) where the sources largely come from the Earth's surface over a wide range of timescales. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. RP Chao, BF (reprint author), NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. EM benjamin.f.chao@nasa.gov RI Chao, Benjamin Fong/N-6156-2013 NR 15 TC 47 Z9 50 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD APR PY 2005 VL 39 IS 3 BP 223 EP 230 DI 10.1016/j.jog.2004.11.001 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 918SE UT WOS:000228567100003 ER PT J AU Vassiliadis, D Fung, SF Klimas, AJ AF Vassiliadis, D Fung, SF Klimas, AJ TI Solar, interplanetary, and magnetospheric parameters for the radiation belt energetic electron flux SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD MEASUREMENTS; RELATIVISTIC ELECTRONS; INNER MAGNETOSPHERE; GEOSYNCHRONOUS ORBIT; GEOMAGNETIC STORMS; WIND; ACCELERATION; PREDICTION; CLOUD; ULF AB In developing models of the radiation belt energetic electron flux, it is important to include the states of the interplanetary medium and the magnetosphere, as well as the solar activity. In this study we choose the log flux j(e)(t;L;E) at 2-6 MeV, as measured by the Proton-Electron Telescope (PET) on SAMPEX in the period 1993-2002, as a representative flux variable and evaluate the usefulness of 17 interplanetary and magnetospheric (IP/MS) parameters in its specification. The reference parameter is the solar wind velocity, chosen because of its known high geoeffectiveness. We use finite impulse response filters to represent the effective coupling of the individual parameters to the log flux. We measure the temporal and spatial scales of the coupling using the impulse response function and the input's geoeffectiveness using the data-model correlation. The correlation profile as a function of L is complex, and we identify its peaks in reference to the radial regions P-0 (L = 3.1-4.0, inner edge of the outer belt), P-1 (4.1-7.5, main outer belt), and P-2 (>7.5, quasi-trapped population), whose boundaries are determined from a radial correlative analysis (Vassiliadis et al., 2003b). Using the profiles, we classify the IP/MS parameters in four categories: ( 1) For the solar wind velocity and pressure the correlation is high and largely independent of L across P-0 and P-1, reaching its maximum in L = 4.8-6.1, or the central part of P-1. (2) The IMF B-South component and related IP/MS parameters have a bimodal correlation function, with peaks in region P-0 (L = 3.0-4.1) and the geosynchronous orbit region within P-1. (3) The IMF B-North and four other interplanetary or solar irradiance parameters have a minimum correlation in P-1, while the highest correlation is in the slot-outer belt boundary (L = 2.5). ( 4) Finally, the solar wind density has a unique correlation profile, which is anticorrelated with that of the solar wind velocity for certain L shells. We verify this classification using more complex filtering methods as well as standard correlation analysis. The categories correspond to four types of solar-terrestrial interactions, namely, viscous interaction, magnetic reconnection, effects of ionospheric heating, and effects of high solar wind density. The response to these interactions produces the observed inner magnetospheric coherence. In each category the L dependence of the correlation profile helps explain why geoeffective solar wind structures are followed by electron acceleration in some L ranges but not in others. C1 NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Univ Space Res Assoc, Goddard Space Flight Ctr, Code 612-2,Bldg 21,Room 265, Greenbelt, MD 20771 USA. EM vassi@electra.gsfc.nasa.gov RI Fung, Shing/F-5647-2012 NR 53 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 2005 VL 110 IS A4 AR A04201 DI 10.1029/2004JA010443 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 916FO UT WOS:000228371000001 ER PT J AU Rodell, M Houser, PR Berg, AA Famiglietti, JS AF Rodell, M Houser, PR Berg, AA Famiglietti, JS TI Evaluation of 10 methods for initializing a land surface model SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID DATA ASSIMILATION SYSTEM; PARAMETERIZATION SCHEMES; CLIMATE MODELS; SOIL-MOISTURE; ETA-MODEL; PROJECT; PHASE; SIMULATIONS; BOUNDARY; IMPACT AB Improper initialization of numerical models can cause spurious trends in the output, inviting erroneous interpretations of the earth system processes that one wishes to study. In particular, soil moisture memory is considerable, so that accurate initialization of this variable in land surface models (LSMs) is critical. The most commonly employed method for initializing an LSM is to spin up by looping through a single year repeatedly until a predefined equilibrium is achieved. The downside to this technique, when applied to continental- to global-scale simulations, is that regional annual anomalies in the meteorological forcing accumulate as artificial anomalies in the land surface states, including soil moisture. Nine alternative approaches were tested and compared using the Mosaic LSM and 15 yr of global meteorological forcing. Results indicate that the most efficient way to initialize an LSM, if possible and given that multiple years of preceding forcing are not available, is to use climatological average states from the same model for the precise time of year of initialization. Three other approaches were also determined to be preferable to the single-year spinup method. In addition, low-resolution spinup scenarios were devised and tested, and based on the results, an effective yet computationally economical technique is proposed. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Guelph, Dept Geog, Guelph, ON N1G 2W1, Canada. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. RP Rodell, M (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974-1, Greenbelt, MD 20771 USA. EM Matthew.Rodell@nasa.gov RI Rodell, Matthew/E-4946-2012; Houser, Paul/J-9515-2013 OI Rodell, Matthew/0000-0003-0106-7437; Houser, Paul/0000-0002-2991-0441 NR 21 TC 53 Z9 53 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD APR PY 2005 VL 6 IS 2 BP 146 EP 155 DI 10.1175/JHM414.1 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 924JN UT WOS:000228975200004 ER PT J AU Lee, HJ AF Lee, HJ TI Layerwise laminate analysis of functionally graded piezoelectric bimorph beams SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article DE finite element method; layerwise laminate theory; smart materials; piezoelectric materials; functionally graded materials ID PLATES; DISPLACEMENT; CERAMICS; ACTUATOR AB A layerwise finite element formulation developed for piezoelectric materials is used to investigate the displacement and stress response of a functionally graded piezoelectric bimorph actuator. The formulation is based on the principles of linear thermopiezoelectricity and accounts for the coupled mechanical, electrical, and thermal responses of piezoelectric materials. The layerwise laminate theory is implemented into a linear beam element in order to provide a more accurate representation of the transverse and shear effects that are induced by the increased inhomogeneities introduced through-the-thickness by the functionally graded materials. The accuracy of the formulation is verified with previously published experimental results for a piezoelectric bimorph actuator. Additional studies are conducted to analyze the impact of electric and thermal loads on the deflections and stresses in a bimorph actuator. Results of the study help to demonstrate the capability of the layerwise theory to provide a more complete representation of the through-the-thickness effects that are no longer negligible even in thin piezoelectric beams. In addition, the effects of varying piezoelectric properties through-the-thickness of the beam are shown to provide additional benefits in minimizing the induced deformations and stresses. C1 NASA, Glenn Res Ctr, Struct Mech & Dynam Branch, Cleveland, OH 44135 USA. RP Lee, HJ (reprint author), NASA, Glenn Res Ctr, Struct Mech & Dynam Branch, 21000 Brookpk Rd,Mail Stop 49-8, Cleveland, OH 44135 USA. EM Ho-Jun.Lee@nasa.gov NR 11 TC 38 Z9 38 U1 0 U2 3 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD APR PY 2005 VL 16 IS 4 BP 365 EP 371 DI 10.1177/1045389X05050100 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 911KT UT WOS:000228001800007 ER PT J AU Wysocki, AB Frank, DN Pace, NR Trent, JD AF Wysocki, AB Frank, DN Pace, NR Trent, JD TI Microbial biodiversity in human chronic wounds SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract CT 66th Annual Meeting of the Society-for-Investigative-Dermatology CY MAY 04-07, 2005 CL St Louis, MO SP Soc Investigat Dermatol C1 Univ Mississippi, Med Ctr, Sch Nursing, Jackson, MS 39216 USA. Univ Mississippi, Med Ctr, Dept Surg, Div Plast Surg, Jackson, MS 39216 USA. Univ Colorado, Boulder, CO 80309 USA. NASA, Bioengn Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL PUBLISHING INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 2005 VL 124 IS 4 SU S MA 259 BP A44 EP A44 PG 1 WC Dermatology SC Dermatology GA 913UT UT WOS:000228179900259 ER PT J AU Broderick, TJ Privitera, MB Parazynski, SE Cuttino, M AF Broderick, TJ Privitera, MB Parazynski, SE Cuttino, M TI Simulated hand-assisted laparoscopic surgery (HALS) in microgravity SO JOURNAL OF LAPAROENDOSCOPIC & ADVANCED SURGICAL TECHNIQUES-PART A LA English DT Article ID SPACE AB Introduction: Previous simulation and porcine experiments aboard the reduced gravity program KC-135 turbojet have demonstrated that microgravity surgery is feasible. Ideally, surgical care in spaceflight will incorporate recent advances in care while remaining easy enough for a crew medical officer (CMO) lacking surgical proficiency or extensive surgical experience to perform. As a minimally invasive surgical technique, hand-assisted laparoscopic surgery (HALS) benefits the patient via smaller incisions, less pain, and faster recovery than traditional open surgery. HALS also helps less experienced laparoscopic surgeons perform laparoscopic surgery. Methods: An inexpensive inanimate surgical simulator was constructed to evaluate the usefulness of HALS in microgravity. This simulator was utilized during brief periods of microgravity provided by parabolic flight on the KC-135. The simulator was successfully used by both a physician-astronaut and an experienced laparoscopic surgeon. Task completion included simulated surgery with exploration of the intestines and ligation of the appendix. Results: Simulated HALS was successfully performed in microgravity. HALS effectively contained operative equipment and small amounts of introduced fluids within the simulated abdominal cavity. Astronaut and surgeon experience suggest that HALS could facilitate minimally invasive surgery (MIS) in microgravity. Discussion: HALS holds promise as a surgical approach in microgravity, particularly as space travel extends beyond low earth orbit. HAILS provides the benefits of MIS, facilitates MIS surgery by less surgically proficient or experienced CMOs, and contains equipment and fluid within the operative field. Simulation provides an easy, cost-effective platform to evaluate medical technology for space flight as well as a method to train CMOs on-orbit. C1 Univ Cincinnati, Dept Surg, Ctr Surg Innovat, Cincinnati, OH 45267 USA. NASA, Lyndon B Johnson Space Ctr, Astronaut Off, Houston, TX 77058 USA. Virginia Commonwealth Univ, Dept Emergency Med, Richmond, VA USA. RP Broderick, TJ (reprint author), Univ Cincinnati, Dept Surg, Ctr Surg Innovat, 231 Albert Sabin Way,SRU Suite 1465, Cincinnati, OH 45267 USA. EM timothy.broderick@uc.edu NR 12 TC 0 Z9 0 U1 0 U2 0 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1092-6429 J9 J LAPAROENDOSC ADV A JI J. Laparoendosc. Adv. Part A PD APR PY 2005 VL 15 IS 2 BP 145 EP 148 DI 10.1089/lap.2005.15.145 PG 4 WC Surgery SC Surgery GA 926JW UT WOS:000229120500008 PM 15898905 ER PT J AU Vilnrotter, V Lau, CW Srinivasan, M Andrews, K Mukai, R AF Vilnrotter, V Lau, CW Srinivasan, M Andrews, K Mukai, R TI Optical array receiver for communication through atmospheric turbulence SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE optical arrays; optical communication; turbulence AB An optical array receiver concept is developed and analyzed. It is shown that for ground-based reception, the number of array elements can be increased without incurring performance degradation, provided the array telescope diameters exceed the coherence-length of the atmosphere. Maximum likelihood detection of turbulence-degraded signal fields is developed for the case of pulse-position modulated signals observed in the presence of background radiation. Performance of optical array receivers is compared to single-aperture receivers with diameters ranging from 4 to 8 m, both in the presence of turbulence and in a turbulence-free environment such as space. It is shown that in the absence of atmospheric turbulence, single-aperture receivers outperform receiver arrays when significant background radiation is present. However, it is also demonstrated that for ground-based reception of deep-space signals, the number of array elements can be as great as several thousand without incurring any performance degradation relative to a large single-aperture receiver. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vilnrotter, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM victor.a.vilnrotter@jpl.nasa.gov NR 13 TC 23 Z9 24 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD APR PY 2005 VL 23 IS 4 BP 1664 EP 1675 DI 10.1109/JLT.2004.841434 PG 12 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 918PY UT WOS:000228561300012 ER PT J AU Shortt, BJ Darrach, MR Holland, PM Chutjian, A AF Shortt, BJ Darrach, MR Holland, PM Chutjian, A TI Miniaturized system of a gas chromatograph coupled with a Paul ion trap mass spectrometer (vol 40, pg 36, 2005) SO JOURNAL OF MASS SPECTROMETRY LA English DT Correction C1 CALTECH, Jet Prop Lab, Atom & Mol Collis Grp, Pasadena, CA 91109 USA. Thorleaf Res Inc, Santa Barbara, CA 93111 USA. RP Shortt, BJ (reprint author), CALTECH, Jet Prop Lab, Atom & Mol Collis Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 2 Z9 2 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1076-5174 J9 J MASS SPECTROM JI J. Mass Spectrom. PD APR PY 2005 VL 40 IS 4 BP 549 EP 549 DI 10.1002/jms.851 PG 1 WC Biochemical Research Methods; Chemistry, Analytical; Spectroscopy SC Biochemistry & Molecular Biology; Chemistry; Spectroscopy GA 923MF UT WOS:000228913300015 ER PT J AU Raman, A Ibekwe, S Gabb, T AF Raman, A Ibekwe, S Gabb, T TI Impulse excitation study of elasticity of different precipitated microstructures in IN738LC at high temperatures SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE elastic softening; impulse excitation; resonant frequency; superalloy IN738LC; Young's modulus at high temperatures ID POLYCRYSTALLINE IN738LC AB The elastic modulus of the cast superalloy IN738LC in various heat-treated conditions was determined with multiple specimens for each microstructure using the impulse excitation technique and the resonant frequencies while heating and cooling. Whereas the second and higher order harmonics were also excited in the high temperature range 700-1000 degrees C in 50 mm long specimens during controlled heating, analogous specimens 35 mm in length, impacted in similar fashion, did not excite the higher harmonics. Also, the 50 mm long specimens became excited and stayed in the second harmonic over broader temperature ranges during uncontrolled cooling inside the closed furnace. All precipitated conditions had nearly similar elastic data, varying from about 200 to 115 GPa, with small deviations, within 5%, found among multiple specimens of similar microstructures tested. Specimens with fine nano-size precipitates had a distinctly smaller rate of decrease in elastic modulus with increasing temperature, in contrast to a somewhat larger and nearly similar rate of decrease in specimens with coarse or medium-sized precipitates. This behavior is indicative of a larger average cohesive strength between the atoms and/or between the matrix and the precipitate particles in the former microstructure. The duplex size precipitate microstructure seemed to have both small and large drops in different specimens. C1 Louisiana State Univ, Dept Mech Engn, Mat Grp, Baton Rouge, LA 70803 USA. So Univ, Dept Mech Engn, Baton Rouge, LA 70813 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Raman, A (reprint author), Louisiana State Univ, Dept Mech Engn, Mat Grp, Baton Rouge, LA 70803 USA. EM meraman@alpha2.eng.lsu.edu NR 8 TC 2 Z9 2 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD APR PY 2005 VL 14 IS 2 BP 188 EP 193 DI 10.1361/10599490523337 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 915VT UT WOS:000228340100006 ER PT J AU Choi, SR Nemeth, NN Gyekenyesi, JP AF Choi, SR Nemeth, NN Gyekenyesi, JP TI Slow crack growth of brittle materials with exponential crack-velocity formulation - Static fatigue SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID CONSTANT-STRESS-RATE; LOADING CONDITIONS; LIFE PREDICTION; INDENTATION FLAWS; DYNAMIC FATIGUE; OPTICAL FIBERS; GLASS; TEMPERATURE; BEHAVIOR; PROPAGATION AB The life prediction analysis based on an exponential crack-velocity formulation was made and examined using a variety of experimental data on advanced structural ceramics in constant stress ('static fatigue' or 'stress rupture') testing at ambient and elevated temperatures. The data fit to the relation between ln (time to failure) versus applied stress was be very reasonable for most of the materials studied, resulting in a similar degree of accuracy as compared with the power-law crack-velocity formulation. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known priori to evaluate the important slow-crack-growth (SCG) parameter n, a drawback as compared with the conventional power-law crack-velocity formulation. (C) 2005 Springer Science + Business Media, Inc. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM sung.r.choi@grc.nasa.gov NR 38 TC 3 Z9 4 U1 1 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR PY 2005 VL 40 IS 7 BP 1647 EP 1654 DI 10.1007/s10853-005-0665-0 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 910UC UT WOS:000227956700012 ER PT J AU Wallace, JM Stone, LS Masson, GS AF Wallace, JM Stone, LS Masson, GS TI Object motion computation for the initiation of smooth pursuit eye movements in humans SO JOURNAL OF NEUROPHYSIOLOGY LA English DT Article ID VISUAL AREA MT; MACAQUE MONKEYS; DIRECTION DISCRIMINATION; TEMPORAL DYNAMICS; CORTICAL-NEURONS; APERTURE PROBLEM; MOVING LINES; INTEGRATION; PERCEPTION; TRACKING AB Pursuing an object with smooth eye movements requires an accurate estimate of its two-dimensional (2D) trajectory. This 2D motion computation requires that different local motion measurements are extracted and combined to recover the global object-motion direction and speed. Several combination rules have been proposed such as vector averaging (VA), intersection of constraints (IOC) or 2D feature tracking (2DFT). To examine this computation, we investigated the time course of smooth pursuit eye movements driven by simple objects of different shapes. For type 11 diamond (where the direction of true object motion is dramatically different from the vector average of the 1-dimensional edge motions, i.e., VA not equal IOC = 2DFT), the ocular tracking is initiated in the vector average direction. Over a period of less than 300 ms, the eye-tracking direction converges oil the true object motion. The reduction of the tracking error starts before the closing of the oculomotor loop. For type I diamonds (where the direction of true object motion is identical to the vector average direction. i.e., VA not equal IOC = 2DFT), there is no Such bias. We quantified this effect by calculating the direction error between responses to types I and II and measuring its maximum value and time constant. At low contrast and high speeds, the initial bias in tracking direction is larger and takes longer to converge onto the actual object-motion direction. This effect is attenuated with the introduction of more 2D information to the extent that it was totally obliterated with a texture-filled type II diamond. These results suggest a flexible 2D computation for motion integration, which combines all available one-dimensional (edge) and 2D (feature) motion information to refine the estimate of object-motion direction over time. C1 CNRS, UMR 6193, INCM, Team DyVa, F-13402 Marseille, France. NASA, Ames Res Ctr, Human Informat Proc Res Branch, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. RP Masson, GS (reprint author), CNRS, UMR 6193, INCM, Team DyVa, 31 Chemin Joseph Aiguier, F-13402 Marseille, France. EM Guillaume.Masson@incm.cnrs-mrs.fr RI MASSON, Guillaume/G-4615-2012 NR 58 TC 30 Z9 30 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-3077 J9 J NEUROPHYSIOL JI J. Neurophysiol. PD APR PY 2005 VL 93 IS 4 BP 2279 EP 2293 DI 10.1152/jn.01042.2004 PG 15 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 907FQ UT WOS:000227701600041 PM 15774715 ER PT J AU Berger, MJ Aftosmis, MJ Marshall, DD Murman, SM AF Berger, MJ Aftosmis, MJ Marshall, DD Murman, SM TI Performance of a new CFD flow solver using a hybrid programming paradigm SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article DE parallel programming; shared address space; message passing; space-filling curves AB This paper presents several algorithmic innovations and a hybrid programming style that lead to highly scalable performance using shared memory for a new computational fluid dynamics flow solver. This hybrid model is then converted to a strict message-passing implementation, and performance results for the two are compared. Results show that using this hybrid approach our OpenMP implementation is actually marginally faster than the MPI version, with parallel speedups of up to 599 out of 640 using OpenMP and 486 with MPI. (c) 2005 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NYU, Courant Inst, New York, NY 10012 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. ELORET, Moffett Field, CA 94035 USA. RP Berger, MJ (reprint author), NASA, Ames Res Ctr, MS T27B, Moffett Field, CA 94035 USA. EM berger@nas.nasa.gov NR 19 TC 12 Z9 12 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD APR PY 2005 VL 65 IS 4 BP 414 EP 423 DI 10.1016/j.jpdc.2004.11.010 PG 10 WC Computer Science, Theory & Methods SC Computer Science GA 912LR UT WOS:000228080300002 ER PT J AU Sauke, TB Becker, JF AF Sauke, TB Becker, JF TI Modeling, measuring, and minimizing the instrument response function of a tunable diode laser spectrometer SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE instrument response function; IRF; tunable diode laser; TDL; spectrometer ID MU-M; SPECTROSCOPY; DIFFERENTIATION; LINEWIDTH; LINE; CONVOLUTION; HETERODYNE AB The instrument response function (IRF) of a spectrometer limits the accuracy of measured spectroscopic parameters by broadening recorded spectral lines/features. We describe methods to model the effects of the IRF on spectral data, to minimize the IRF widths, and to measure the resulting width of the spectrometer IRF. We have modeled the IRF of our Tunable Diode Laser Spectrometer as a Voigt function. A real-time method of eliminating the effects of low-frequency spectrometer drift has been implemented and has resulted in a substantial reduction in the width of the IRF, its residual Gaussian component reduced from about 0.00045 cm(-1) to about 0.0002 cm(-1). An accurate measurement of the IRF Gaussian width utilizes a computationally simple method making use of the spectral dependence of the RMS noise of each signal-averaged data point. Various noise sources affecting the spectrometer (preamp/detector noise, laser AM noise, and laser FM noise) are identified and separately quantified by use of the same method. The IRF Gaussian-width measurement can be automatically applied to each measured spectrum of an experimental data set. A related method is discussed which allows accurate determination of the spectral dependence of statistical noise appropriate for use in quantitative Chi-square fitting of absorption spectra. We explore simple, efficient numerical processes which can dramatically enhance the quality and usefulness of acquired spectral data, improving the ability to apply TDL spectroscopy to high-precision, quantitative measurements and the determination of detailed spectroscopic lineshape parameters. This paper provides a guide for interested readers to implement these developments in their own spectrometers. (C) 2004 Elsevier Ltd. All rights reserved. C1 NASA Ames Res Ctr, SETI Inst, Moffett Field, CA 94043 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP NASA Ames Res Ctr, SETI Inst, MS 239-4, Moffett Field, CA 94043 USA. EM tsauke@mail.arc.nasa.gov NR 28 TC 9 Z9 9 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 EI 1879-1352 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR 1 PY 2005 VL 91 IS 4 BP 453 EP 484 DI 10.1016/j.jqsrt.2004.07.005 PG 32 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 874JH UT WOS:000225346200005 ER PT J AU Cartoixa, X Ting, DZY Chang, YC AF Cartoixa, X Ting, DZY Chang, YC TI [111] heterostructures for spin devices SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE spintronics; D'yakonov-Perel; bulk inversion asymmetry; Rashba; [111] heterostructures ID QUANTUM-WELLS; RELAXATION ANISOTROPY; ELECTRONS; SEMICONDUCTORS; TRANSISTOR AB The symmetry properties of [111] quantum wells (QWs) and superlattices, and in particular the fact that the symmetry is not reduced when bulk inversion asymmetry (BIA) is supplemented with structural inversion asymmetry [SIA (Rashba)], have important consequences for spin dynamics and transport. We compute the effective spin Hamiltonians for [111] and [110] structures, and show that for the [111] case the splitting can be made to vanish to lowest order when BIA and SIA effects are of equal strength. As a consequence, the D'yakonov Perel' spin relaxation mechanism is suppressed for all spin components. This effect forms the base for an improved version of the Datta-Das and a recently proposed family of spin transistors. For [110]-grown QWs, the effect of SIA is to augment the spin relaxation rate of the component perpendicular to the well. We derive analytical expressions for the spin lifetime tensor and its proper axes, and see that they are dependent on the relative magnitude of the BIA- and SIA-induced splittings. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cartoixa, X (reprint author), Univ Illinois, Dept Phys, Urbana, IL 61801 USA. EM XCartoixa-Soler@lbl.gov RI Chang, Yia-Chung/F-4239-2011 NR 33 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD APR PY 2005 VL 18 IS 2 BP 163 EP 168 DI 10.1007/s10948-005-3353-z PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 924ZY UT WOS:000229022500005 ER PT J AU Feng, F Mal, A Kabo, M Wang, JC Bar-Cohen, Y AF Feng, F Mal, A Kabo, M Wang, JC Bar-Cohen, Y TI The mechanical and thermal effects of focused ultrasound in a model biological material SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID SURGERY; TEMPERATURE; TISSUE AB This paper is motivated by possible medical applications of focused ultrasound in the minimally invasive treatment of a variety of musculoskeletal disorders that are responsive to thermal treatment. A model-based analysis of the interaction of high-intensity focused ultrasound with biological materials is carried out in an effort to predict the path of the sound waves and the temperature field in the focal region. A finite-element-based general purpose code called PZFlex is used to determine the effects of nonlinearity and geometrical complexity of biological structures. It was found that at frequencies of interest in therapeutic applications, the nonlinear effects are usually negligible and the geometrical complexities can be handled through a substructuring procedure. An approximate analytical method with acceptable accuracy is developed as an alternative to the purely numerical approach used in PZFlex. The mechanical and thermal effects in two-layered fluid material systems induced by high-frequency focused ultrasound are calculated through this analytical method. The results are compared with those obtained using PZFlex as a benchmark. (c) 2005 Acoustical Society of America. C1 Univ Calif Los Angeles, Mech & Aerosp Engn Dept, Los Angeles, CA 90095 USA. Calif State Univ Northridge, Coll Engn & Comp Sci, Northridge, CA 91330 USA. Univ Calif Los Angeles, Dept Orthopaed & Neurosurg, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Calif Los Angeles, Mech & Aerosp Engn Dept, Los Angeles, CA 90095 USA. EM ajit@seas.ucla.edu NR 28 TC 8 Z9 8 U1 0 U2 3 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 EI 1520-8524 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD APR PY 2005 VL 117 IS 4 BP 2347 EP 2355 DI 10.1121/1.1873372 PN 1 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 919OW UT WOS:000228628400060 PM 15898675 ER PT J AU Kufeld, RM Bousman, WG AF Kufeld, RM Bousman, WG TI Technical note - UH-60A airloads program azimuth reference correction SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article ID DYNAMIC STALL; FLIGHT AB Recent investigation of airloads data from the Army/NASA UH-60A Airloads Program has revealed an important error in the azimuthal reference used for comparison with rotorcraft analyses. A 7 degrees difference exists between flight test and analysis reference systems because of the offset of the elastomeric bearing from the hub axis. Most previously published data applied this 7 degrees shift in the wrong direction. Correction to published data, therefore, requires a 14 degrees shift to the left for azimuthally referenced data. The correction of the reference error has significantly improved correlation of comprehensive and especially coupled CFD analyses with the UH-60A Airloads Program data. Most publications prior to January 2005 utilize data with the incorrect azimuth reference. A list of affected Army/NASA publications is included in this paper. C1 NASA, Ames Res Ctr, Flight Vehicle Res & Technol Div, Moffett Field, CA 94035 USA. USA, Res Dev & Engn Command, Aeroflightdynam Directorate, Moffett Field, CA USA. RP Kufeld, RM (reprint author), NASA, Ames Res Ctr, Flight Vehicle Res & Technol Div, Moffett Field, CA 94035 USA. NR 18 TC 14 Z9 14 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD APR PY 2005 VL 50 IS 2 BP 211 EP 213 PG 3 WC Engineering, Aerospace SC Engineering GA 928CW UT WOS:000229249700008 ER PT J AU Roithmayr, CM Kay-Bunnell, L AF Roithmayr, CM Kay-Bunnell, L TI Keeping a spacecraft on the sun-earth line SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS/AIAA 14th Space Flight Mechanics Meeting CY FEB 08-12, 2004 CL Maui, HI SP AAS, Amer Inst Aeronaut & Astronaut ID ORBITS AB Measurements of Earth's atmosphere as it occults sunlight can be obtained advantageously from a spacecraft placed in the proximity of the Sun-Earth Lagrange point L(2). Maintaining the condition of continuous solar occultation by all parts of the atmospheric disk requires that the displacement of the spacecraft perpendicular to the Sun-Earth line remains less than 200 kin. However, the gravitational force exerted by the Earth's moon must be negated by propulsion in order to meet this rather tight constraint. We provide an estimate of propulsive force needed to keep the spacecraft coincident with L(2). as well as estimates of velocity increments needed to maintain various trajectories in the close vicinity of L(2). C1 NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Hampton, VA 23681 USA. RP Roithmayr, CM (reprint author), NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Hampton, VA 23681 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 2005 VL 53 IS 2 BP 131 EP 146 PG 16 WC Engineering, Aerospace SC Engineering GA 019QA UT WOS:000235850600002 ER PT J AU Carpenter, JR Alfriend, KT AF Carpenter, JR Alfriend, KT TI Navigation accuracy guidelines for orbital formation flying SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB Some simple guidelines based on the accuracy in determining a satellite formation's semimajor axis differences are useful in making preliminary assessments of the navigation accuracy needed to support such missions. These guidelines are valid for ally elliptical orbit, regardless of eccentricity. Although maneuvers required for formation establishment, reconfiguration, and station-keeping require accurate prediction of the state estimate to the maneuver time, and hence are directly affected by errors in all the orbital elements, experience has shown that determination of orbit plane orientation and orbit shape to acceptable levels is less challenging than the determination of orbital period or semimajor axis. Furthermore, any differences among the members' semimajor axes are undesirable for a satellite formation, since they will lead to differential in-track drift due to period differences. Since inevitable navigation errors prevent these differences from ever being zero, one may use the guidelines this paper presents to determine how Much drift will result from a given relative navigation accuracy, or conversely what navigation accuracy is required to limit drift to a given value. Since the guidelines do not account for perturbations, they may be viewed as useful preliminary design tools, rather than as the basis for mission navigation requirements, which should be based on detailed analysis of the mission configuration, including all relevant sources of uncertainty. C1 NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. RP Carpenter, JR (reprint author), NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Code 595, Greenbelt, MD 20771 USA. NR 6 TC 7 Z9 7 U1 0 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 2005 VL 53 IS 2 BP 207 EP 219 PG 13 WC Engineering, Aerospace SC Engineering GA 019QA UT WOS:000235850600007 ER PT J AU Smith, WL Charlock, TP Kahn, R Martins, JV Remer, LA Hobbs, PV Redemann, J Rutledge, CK AF Smith, WL Charlock, TP Kahn, R Martins, JV Remer, LA Hobbs, PV Redemann, J Rutledge, CK TI EOS Terra aerosol and radiative flux validation: An overview of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID WATER-VAPOR; INSTRUMENT DESCRIPTION; RADIANCE MEASUREMENTS; OBSERVING SYSTEM; DRY SEASON; RETRIEVAL; CLOUDS; OCEAN; NETWORK; SURFACE AB NASA developed an Earth Observing System (EOS) to study global change and reduce uncertainties associated with aerosols and other key parameters controlling climate. The first EOS satellite, Terra, was launched in December 1999. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign was conducted from 10 July to 2 August 2001 to validate several Terra data products, including aerosol properties and radiative flux profiles derived from three complementary Terra instruments: the Clouds and the Earth's Radiant Energy System (CERES), the Multiangle Imaging Spectroradiometer (MISR), and the Moderate Resolution Imaging Spectroradiometer (MODIS). CERES, MISR, and MODIS are being used to investigate the critical role aerosols play in modulating the radiative heat budget of the earth-atmosphere system. CLAMS' primary objectives are to improve understanding of atmospheric aerosols, to validate and improve the satellite data products, and to test new instruments and measurement concepts. A variety of in situ sampling devices and passive remote sensing instruments were flown on six aircraft to characterize the state of the atmosphere, the composition of atmospheric aerosols, and the associated surface and atmospheric radiation parameters over the U.S. eastern seaboard. Aerosol particulate matter was measured at two ground stations established at Wallops Island, Virginia, and the Chesapeake Lighthouse, the site of an ongoing CERES Ocean Validation Experiment (COVE) where well-calibrated radiative fluxes and Aerosol Robotic Network (AERONET) aerosol properties have been measured since 1999. Nine coordinated aircraft missions and numerous additional sorties were flown under a variety of atmospheric conditions and aerosol loadings. On one "golden day" (17 July 2001), under moderately polluted conditions with midvisible optical depths near 0.5, all six aircraft flew coordinated patterns vertically stacked between 100 and 65 000 It over the COVE site as Terra flew overhead. This overview presents a description of CLAMS objectives, measurements, and sampling strategies. Key results, reported in greater detail in the collection of papers found in this special issue, are also summarized. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Bay Area Environm Res Inst, Sonoma, CA USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Smith, WL (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. EM william.l.smith@nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 49 TC 15 Z9 15 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 903 EP 918 DI 10.1175/JAS3398.1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000002 ER PT J AU Castanho, ADD Martins, JV Hobbs, PV Artaxo, P Remer, L Yamasoe, M Colarco, PR AF Castanho, ADD Martins, JV Hobbs, PV Artaxo, P Remer, L Yamasoe, M Colarco, PR TI Chemical characterization of aerosols on the east coast of the United States using aircraft and ground-based stations during the CLAMS experiment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; SOURCE APPORTIONMENT; SAHARAN DUST; BRAZIL; PRIDE; TRANSPORT; POLLUTION; AIRBORNE; AFRICA; PIXE AB The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment was carried out off the central East Coast of the United States in July 2001. During CLAMS, aerosol particle mass was measured at two ground stations and on the University of Washington's Convair 580 research aircraft. Physical and chemical characteristics of the aerosols were identified and quantified. Three main aerosol regimes were identified in the region and are discussed in this work: local pollution/sea salt back,ground, long-range transported dust, and long-range transported pollution. The major component measured in the fine mode of the aerosol on the ground at Wallops Island, Virginia, was sulfate, estimated as NH4HSO4, which accounted for 55% +/- 9% on average of the fine particle mass (FPM) during the experiment period. Black carbon concentrations accounted for 3% +/- 1% of FPM; soil dust was also present, representing on average 6% +/- 8% of FPM. The difference between the sum of the masses of the measured compounds and the total fine particle mass was 36% +/- 10% of FPM, which is attributed primarily to nitrates and organic carbon that were not measured. Aerosol chemical composition in the atmospheric column is also discussed and compared with ground-based measurements. Aerosol dust concentration reached 40% of FPM during an incursion of Saharan dust between 24 and 26 July. Sulfate aerosol reached 70% of FPM during the transport of regional pollution on 17 July. Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness, coupled with air parcel back trajectories, supported the conclusion of episodes of long-range transport of dust from the Sahara Desert and pollutants from the continental United States. C1 Univ Sao Paulo, Inst Phys, BR-05508900 Sao Paulo, Brazil. Univ Maryland, JCET, Baltimore, MD 21201 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, BR-05508900 Sao Paulo, Brazil. Univ Maryland Baltimore Cty, Earth Syst Sci Interdisciplinary Ctr, Baltimore, MD 21201 USA. RP Castanho, ADD (reprint author), Univ Sao Paulo, Inst Phys, Rua Matao,Travessa R,187 Cidade Univ, BR-05508900 Sao Paulo, Brazil. EM castanho@if.usp.br RI Yamasoe, Marcia/L-3667-2013; Artaxo, Paulo/E-8874-2010; Colarco, Peter/D-8637-2012 OI Yamasoe, Marcia/0000-0003-3066-9146; Artaxo, Paulo/0000-0001-7754-3036; Colarco, Peter/0000-0003-3525-1662 NR 24 TC 9 Z9 10 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 934 EP 946 DI 10.1175/JAS3388.1 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000004 ER PT J AU Remer, LA Kaufman, YJ Tanre, D Mattoo, S Chu, DA Martins, JV Li, RR Ichoku, C Levy, RC Kleidman, RG Eck, TF Vermote, E Holben, BN AF Remer, LA Kaufman, YJ Tanre, D Mattoo, S Chu, DA Martins, JV Li, RR Ichoku, C Levy, RC Kleidman, RG Eck, TF Vermote, E Holben, BN TI The MODIS aerosol algorithm, products, and validation SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; TROPOSPHERIC AEROSOLS; OPTICAL-PROPERTIES; AIRBORNE SIMULATOR; SIZE DISTRIBUTION; SAFARI 2000; SCAR-B; AERONET; CLOUDS; OCEANS AB The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard both NASA's Terra and Aqua satellites is making near-global daily observations of the earth in a wide spectral range (0.41-15 mu m). These measurements are used to derive spectral aerosol optical thickness and aerosol size parameters over both land and ocean. The aerosol products available over land include aerosol optical thickness at three visible wavelengths, a measure of the fraction of aerosol optical thickness attributed to the fine mode, and several derived parameters including reflected spectral solar flux at the top of the atmosphere. Over the ocean, the aerosol optical thickness is provided in seven wavelengths from 0.47 to 2.13 mu m. In addition, quantitative aerosol size information includes effective radius of the aerosol and quantitative fraction of optical thickness attributed to the fine mode. Spectral irradiance contributed by the aerosol, mass concentration, and number of cloud condensation nuclei round out the list of available aerosol products over the ocean. The spectral optical thickness and effective radius of the aerosol over the ocean are validated by comparison with two years of Aerosol Robotic Network (AERONET) data gleaned from 132 AERONET stations. Eight thousand MODIS aerosol retrievals collocated with AERONET measurements confirm that one standard deviation of MODIS optical thickness retrievals fall within the predicted uncertainty of Delta tau = +/- 0.03 +/- 0.05 tau over ocean and Delta tau = +/- 0.05 +/- 0.15 tau over land. Two hundred and seventy-one MODIS aerosol retrievals collocated with AERONET inversions at island and coastal sites suggest that one standard deviation of MODIS effective radius retrievals falls within Delta r(eff) = +/- 0.11 mu m. The accuracy of the MODIS retrievals suggests that the product can be used to help narrow the uncertainties associated with aerosol radiative forcing of global climate. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM Lorraine.A.Remer@nasa.gov RI ECK, THOMAS/D-7407-2012; Ichoku, Charles/E-1857-2012; Vermote, Eric/K-3733-2012; Levy, Robert/M-7764-2013; Franco-Hurtado, Fernando/E-5599-2017 OI Ichoku, Charles/0000-0003-3244-4549; Levy, Robert/0000-0002-8933-5303; Franco-Hurtado, Fernando/0000-0001-5775-0150 NR 45 TC 1441 Z9 1525 U1 41 U2 244 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 947 EP 973 DI 10.1175/JAS3385.1 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000005 ER PT J AU Levy, RC Remer, LA Martins, JV Kaufman, YJ Plana-Fattori, A Redemann, J Wenny, B AF Levy, RC Remer, LA Martins, JV Kaufman, YJ Plana-Fattori, A Redemann, J Wenny, B TI Evaluation of the MODIS aerosol retrievals over ocean and land during CLAMS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; WATER-VAPOR; ATMOSPHERIC CORRECTION; TROPOSPHERIC AEROSOL; SURFACE REFLECTANCE; SPECTRAL RADIANCES; PRECIPITABLE WATER; OPTICAL-PROPERTIES; SUN PHOTOMETER; AIR-POLLUTION AB The Chesapeake Lighthouse Aircraft Measurements for Satellites (CLAMS) experiment took place from 10 July to 2 August 2001 in a combined ocean-land region that included the Chesapeake Lighthouse [Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE)] and the Wallops Flight Facility (WFF), both along coastal Virginia. This experiment was designed mainly for validating instruments and algorithms aboard the Terra satellite platform, including the Moderate Resolution Imaging Spectroradiometer (MODIS). Over the ocean, MODIS retrieved aerosol optical depths (AODs) at seven wavelengths and an estimate of the aerosol size distribution. Over the land. MODIS retrieved AOD at three wavelengths plus qualitative estimates of the aerosol size. Temporally coincident measurements of aerosol properties were made with a variety of sun photometers from ground sites and airborne sites just above the surface. The set of sun photometers provided unprecedented spectral coverage from visible (VIS) to the solar near-infrared (NIR) and infrared (IR) wavelengths. In this study. AOD and aerosol size retrieved from MODIS is compared with similar measurements from the sun photometers. Over the nearby ocean, the MODIS AOD in the VIS and NIR correlated well with sun-photometer measurements, nearly fitting a one-to-one line on a scatterplot. As one moves from ocean to land, there is a pronounced discontinuity of the MODIS AOD, where MODIS compares poorly to the sun-photometer measurements. Especially in the blue wavelength, MODIS AOD is too high in clean aerosol conditions and too low under larger aerosol loadings. Using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) radiative code to perform atmospheric correction. the authors find inconsistency, in the surface albedo assumptions used by the MODIS lookup tables. It is demonstrated how the high bias at low aerosol loadings can be corrected. By using updated urban/industrial aerosol climatolog for the MODIS lookup table over land, it is shown that the low bias for larger aerosol loadings can also be corrected. Understanding and improving MODIS retrievals over the East Coast may point to strategies for correction in other locations, thus improving the global quality of MODIS. Improvements in regional aerosol detection could also lead to the use of MODIS for monitoring air pollution. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD 21201 USA. Bay Area Environm Res Inst, Sonoma, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SAIC, Hampton, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Levy, RC (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM levy@climate.gsfc.nasa.gov RI Levy, Robert/M-7764-2013 OI Levy, Robert/0000-0002-8933-5303 NR 44 TC 119 Z9 130 U1 3 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 974 EP 992 DI 10.1175/JAS3391.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000006 ER PT J AU Redemann, J Schmid, B Eilers, JA Kahn, R Levy, RC Russell, PB Livingston, JM Hobbs, PV Smith, WL Holben, BN AF Redemann, J Schmid, B Eilers, JA Kahn, R Levy, RC Russell, PB Livingston, JM Hobbs, PV Smith, WL Holben, BN TI Suborbital measurements of spectral aerosol optical depth and its variability at subsatellite grid scales in support of CLAMS 2001 SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; GROUND-BASED MEASUREMENTS; COLUMNAR WATER-VAPOR; TROPOSPHERIC AEROSOL; SOUTHERN AFRICA; DRY SEASON; IN-SITU; AIRBORNE; SUN; AERONET AB As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, 10 July-2 August 2001, off the central East Coast of the United States, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated aboard the University of Washington's Convair 580 (CV-580) research aircraft during 10 flights (similar to 45 flight hours). One of the main research goals in CLAMS was the validation of satellite-based retrievals of aerosol properties. The goal of this study in particular was to perform true over-ocean validations (rather than over-ocean validation with ground-based, coastal sites) at finer spatial scales and extending to longer wavelengths than those considered in previous studies. Comparisons of aerosol optical depth (AOD) between the Aerosol Robotic Network (AERONET) Cimel instrument at the Chesapeake Lighthouse and airborne measurements by AATS-14 in its vicinity showed good agreement with the largest r-square correlation coefficients at wavelengths of 0.38 and 0.5 mu m (> 0.99). Coordinated low-level flight tracks of the CV-580 during Terra overpass times permitted validation of over-ocean Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 (MOD04_L2) multi-wavelength ACID data (10 km x 10 km, nadir) in 16 cases on three separate days. While the correlation between AATS-14- and MODIS-derived ACID was weak with an r square of 0.55, almost 75% of all MODIS AOD measurements fell within the prelaunch estimated uncertainty range Delta tau = +/- 0.03 +/- 0.05 tau. This weak correlation may be due to the small AODs (generally less than 0.1 at 0.5 mu m) encountered in these comparison cases. An analogous coordination exercise resulted in seven coincident over-ocean matchups between AATS-14 and Multiangle Imaging Spectroradiometer (MISR) measurements. The comparison between AATS-14 and the MISR standard algorithm regional mean AODs showed a stronger correlation with an r square of 0.94. However, MISR AODs were systematically larger than the corresponding AATS values, with an rms difference of similar to 0.06. AATS data collected during nine extended low-level CV-580 flight tracks were used to assess the spatial variability in AOD at horizontal scales up to 100 km. At UV and midvisible wavelengths, the largest absolute gradients in AOD were 0.1-0.2 per 50-km horizontal distance. In the near-IR, analogous gradients rarely reached 0.05. On any given day, the relative gradients in AOD were remarkably similar for all wavelengths, with maximum values of 70% (50 km)(-1) and more typical values of 25% (50 km)(-1). The implications of these unique measurements of AOD spatial variability for common validation practices of satellite data products and for comparisons to large-scale aerosol models are discussed. C1 NASA, Ames Res Ctr, BAERI, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA USA. Jet Propuls Lab, Pasadena, CA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SRI Int, Menlo Pk, CA 94025 USA. Univ Washington, Seattle, WA 98195 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Redemann, J (reprint author), NASA, Ames Res Ctr, BAERI, MS 345-5, Moffett Field, CA 94035 USA. EM jredemann@mail.arc.nasa.gov RI Levy, Robert/M-7764-2013; Kahn, Ralph/D-5371-2012 OI Levy, Robert/0000-0002-8933-5303; Kahn, Ralph/0000-0002-5234-6359 NR 44 TC 35 Z9 36 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 993 EP 1007 DI 10.1175/JAS3387.1 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000007 ER PT J AU Ignatov, A Minnis, P Loeb, N Wielicki, B Miller, W Sun-Mack, S Tanre, D Remer, L Laszlo, I Geier, E AF Ignatov, A Minnis, P Loeb, N Wielicki, B Miller, W Sun-Mack, S Tanre, D Remer, L Laszlo, I Geier, E TI Two MODIS aerosol products over ocean on the Terra and Aqua CERES SSF datasets SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID INDIVIDUAL AVHRR CHANNELS; ENERGY SYSTEM CERES; INFORMATION-CONTENT; RETRIEVALS; SENSITIVITY; ATMOSPHERE; CLOUDS; 6S AB Understanding the impact of aerosols on the earth's radiation budget and the long-term climate record requires consistent measurements of aerosol properties and radiative fluxes. The Clouds and the Earth's Radiant Energy System (CERES) Science Team combines satellite-based retrievals of aerosols. clouds, and radiative fluxes into Single Scanner Footprint (SSF) datasets from the Terra and Aqua satellites. Over ocean, two aerosol products are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) using different sampling and aerosol algorithms. The primary, or M. product is taken from the standard multispectral aerosol product developed by the MODIS aerosol group while a simpler, secondary [Advanced Very High Resolution Radiometer (AVHRR) like], or A. product is derived by the CERES Science Team using a different cloud clearing method and a single-channel aerosol algorithm. Two aerosol optical depths (AOD) tau(A1) and tau(A2), are derived from MODIS bands 1 (0.644 mu m) and 6 (1.632 mu m) resembling the AVHRR/3 channels 1 and 3A, respectively. On Aqua the retrievals are made in band 7 (2.119 mu m) because of poor quality data from band 6. The respective angstrom ngstrom exponents can be derived from the values of T. The A product serves as a backup for the M product. More importantly. the overlap of these aerosol products is essential for placing the 20+ year heritage AVHRR aerosol record in the context of more advanced aerosol sensors and algorithms such as that used for the M product. This study documents the M and A products, highlighting their CERES SSF specifics. Based on 2 weeks of global Terra data, coincident M and A AODS are found to be strongly correlated in both bands. However, both domains in which the M and A aerosols are available, and the respective tau/alpha statistics significantly differ because of discrepancies in sampling due to differences in cloud and sun-glint screening, In both aerosol products, correlation is observed between the retrieved aerosol parameters (tau/alpha) and ambient cloud amount, with the dependence in the M product being more pronounced than in the A product. C1 NESDIS, NOAA, Off Res & Applicat, Camp Springs, MD USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Sci Applicat Int Corp, Hampton, VA USA. Univ Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ignatov, A (reprint author), E RA1,Rm 603,5200 Auth Rd, Camp Springs, MD 20746 USA. EM Alex.Ignatov@noaa.gov RI Ignatov, Alexander/F-5594-2010; Laszlo, Istvan/F-5603-2010; Minnis, Patrick/G-1902-2010 OI Ignatov, Alexander/0000-0002-7463-5944; Laszlo, Istvan/0000-0002-5747-9708; Minnis, Patrick/0000-0002-4733-6148 NR 33 TC 42 Z9 43 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1008 EP 1031 DI 10.1175/JAS3383.1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000008 ER PT J AU Kahn, R Li, WH Martonchik, JV Bruegge, CJ Diner, DJ Gaitley, BJ Abdou, W Dubovik, O Holben, B Smirnov, A Jin, ZH Clark, D AF Kahn, R Li, WH Martonchik, JV Bruegge, CJ Diner, DJ Gaitley, BJ Abdou, W Dubovik, O Holben, B Smirnov, A Jin, ZH Clark, D TI MISR calibration and implications for low-light-level aerosol retrieval over dark water SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ANGLE IMAGING SPECTRORADIOMETER; SKY RADIANCE MEASUREMENTS; IN-FLIGHT PERFORMANCE; OPTICAL-PROPERTIES; INSTRUMENT DESCRIPTION; ATMOSPHERIC AEROSOL; OCEAN; NETWORK; AERONET; SENSITIVITY AB (S)tudying aerosols over ocean is one goal of the Multiangle Imaging Spectroradiometer (MISR) and other spaceborne imaging systems. But top-of-atmosphere equivalent reflectance typically falls in the range of 0.03 to 0.12 at midvisible wavelengths and can be below 0.01 in the near-infrared. when an optically thin aerosol layer is viewed over a dark ocean surface. Special attention must be given to radiometric calibration if aerosol optical thickness, and any information about particle microphysical properties, are to be reliably retrieved from such observations. MISR low-light-level vicarious calibration is performed in the vicinity of remote islands hosting Aerosol Robotic Network (AERONET) sun- and sky-scanning radiometers. under low aerosol loading, low wind speed, relatively cloud free conditions. MISR equivalent reflectance is compared with values calculated from a radiative transfer model constrained by coincident, AERONET-retrieved aerosol spectral optical thickness. size distribution, and single scattering albedo, along with in situ wind measurements. Where the nadir view is not in sun glint, MISR equivalent reflectance is also compared with Moderate Resolution Imaging Spectroradionieter (MODIS) reflectance. The authors push the limits of the vicarious calibration method's accuracy, aiming to assess absolute, camera-to-camera, and band-to-band radiometry. Patterns repeated over many well-constrained cases lend confidence to the results, at a few percent accuracy, as do additional vicarious calibration tests performed with multiplatform observations taken during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) campaign. Conclusions are strongest in the red and green bands, but are too uncertain to accept for the near-infrared. MISR nadir-view and MODIS low-light-level absolute reflectances differ by about 4% in the blue and green bands, with MISR reporting higher values. In the red, MISR agrees with MODIS band 14 to better than 2%, whereas MODIS band 1 is significantly lower. Compared to the AERONET-constrained model. the MISR aft-viewing cameras report reflectances too high by several percent in the blue, green, and possibly the red. Better agreement is found in the nadir- and the forward-viewing cameras, especially in the blue and green. When implemented on a trial basis, calibration adjustments indicated by this work remove 40% of a 0.05 bias in retrieved midvisible aerosol optical depth over dark water scenes, produced by the early postlaunch MISR algorithm. A band-to-band correction has already been made to the MISR products. and the remaining calibration adjustments, totaling no more than a few percent, are planned. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Langley, VA USA. NESDIS, NOAA, Camp Springs, MD USA. RP Kahn, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ralph.Kahn@jpl.nasa.gov RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Kahn, Ralph/D-5371-2012 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Kahn, Ralph/0000-0002-5234-6359 NR 41 TC 36 Z9 36 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1032 EP 1052 DI 10.1175/JAS3390.1 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000009 ER PT J AU Jin, ZH Charlock, TP Rutledge, K Cota, G Kahn, R Redemann, J Zhang, TP Rutan, DA Rose, F AF Jin, ZH Charlock, TP Rutledge, K Cota, G Kahn, R Redemann, J Zhang, TP Rutan, DA Rose, F TI Radiative transfer modeling for the CLAMS experiment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ENERGY SYSTEM CERES; OPTICAL-PROPERTIES; LAYERED MEDIA; INSTRUMENT; CLOUDS; RETRIEVAL; ALGORITHM; AEROSOLS; NETWORK; SURFACE AB Spectral and broadband radiances and irradiances (fluxes) were measured from surface, airborne, and space-borne platforms in the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) campaign. The radiation data obtained on the 4 clear days over ocean during CLAMS are analyzed here with the Coupled Ocean-Atmosphere Radiative Transfer (COART) model. The model is successively compared with observations of broadband fluxes and albedos near the ocean surface from the Clouds and the Earth's Radiant Energy System (CERES) Ocean Validation Experiment (COVE) sea platform and a low-level OV-10 aircraft, of near-surface spectral albedos from COVE and OV-10, of broadband radiances at multiple angles and inferred top-of-atmosphere (TOA) fluxes from CERES, and of spectral radiances at multiple angles from Airborne Multiangle Imaging Spectroradiometer (MISR), or "AirMISR," at 20-km altidude. The radiation measurements from different platforms are shown to be consistent with each other and with model results. The discrepancies between the model and observations at the surface are less than 10 W m(-2) for downwelling and 2 W m(-2) for upwelling fluxes. The model-observation discrepancies for shortwave ocean albedo are less than 8%; some discrepancies in spectral albedo are larger but less than 20%. The discrepancies between low-altitude aircraft and surface measurements are somewhat larger than those between the model and the surface measurements; the former are due to the effects of differences in height, aircraft pitch and roll, and the noise of spatial and temporal variations of atmospheric and oceanic properties. The discrepancy between the model and the CERES observations for the upwelling radiance is 5.9% for all angles; this is reduced to 4.9% if observations within 15 degrees of the sun-glint angle are excluded. The measurements and model agree on the principal impacts that ocean optical properties have on upwelling radiation at low levels in the atmosphere. Wind-driven surface roughness significantly affects the upwelling radiances measured by aircraft and satellites at small sun-glint angles, especially in the near-infrared channel of MISR. Intercomparisons of various measurements and the model show that most of the radiation observations in CLAMS are robust, and that the coupled radiative transfer model used here accurately treats scattering and absorption processes in both the air and the water. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Bay Area Environm Res Inst, Sonoma, CA USA. RP Jin, ZH (reprint author), Analyt Serv & Mat Inc, 1 Enterprise Pkwy,Suite 300, Hampton, VA 23666 USA. EM z.jin@larc.nasa.gov RI Kahn, Ralph/D-5371-2012; OI Kahn, Ralph/0000-0002-5234-6359; Rose, Fred G/0000-0003-0769-0772 NR 19 TC 8 Z9 8 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1053 EP 1071 DI 10.1175/JAS3351.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000010 ER PT J AU Gatebe, CK King, MD Lyapustin, AI Arnold, GT Redemann, J AF Gatebe, CK King, MD Lyapustin, AI Arnold, GT Redemann, J TI Airborne spectral measurements of ocean directional reflectance SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SURFACE-ATMOSPHERE ANISOTROPY; AEROSOL OPTICAL-THICKNESS; WATER-LEAVING RADIANCE; ABOVE-WATER; BIDIRECTIONAL REFLECTANCE; DIFFUSE-REFLECTANCE; VECTOR WINDS; RETRIEVAL; GLITTER; SEAWIFS AB The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair 580 (CV-580) research aircraft during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign and obtained measurements of bidirectional reflectance distribution function (BRDF) of the ocean in July and August 2001 under different illumination conditions with solar zenith angles ranging from 15 degrees to 46 degrees. The BRDF measurements were accompanied by concurrent measurements of atmospheric aerosol optical thickness and column water vapor above the airplane. The method of spherical harmonics with Cox-Munk wave-slope distribution is used in a new algorithm developed for this study to solve the atmosphere-ocean radiative transfer problem and to remove the effects of the atmosphere from airborne measurements. The algorithm retrieves simultaneously the wind speed and full ocean BRDF (sun's glitter and water-leaving radiance) from CAR measurements and evaluates total albedo and equivalent albedo for the water-leaving radiance outside the glitter. Results show good overall agreement with other measurements and theoretical simulations, with the anisotropy of the water-leaving radiance clearly seen. However, the water-leaving radiance does not show a strong dependence on solar zenith angle as suggested by some theoretical studies. The spectral albedo was found to vary from 4.1%-5.1% at lambda = 0.472 mu m to 2.4%-3.5% for lambda >= 0.682 mu m. The equivalent water-leaving albedo ranges from 1.0%-2.4% at lambda = 0.472 mu m to 0.1%-0.6% for lambda = 0.682 Am and 0.1%-0.3% for lambda = 0.870 mu m. Results of the validation of the Cox-Munk model under the conditions measured show that although the model reproduces the shape of sun's glitter on average with an accuracy of better than 30%, it underestimates the center of the sun's glitter reflectance by about 30% for low wind speeds (< 2-3 m s(-1)). In cases of high wind speed, the model with Gram-Charlier expansion seems to provide the best fit. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. L3 Commun Govt Serv Inc, Vienna, VA USA. Bay Area Environm Res Inst, Sonoma, CA USA. RP Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM gatebe@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011; Gatebe, Charles/G-7094-2011; Lyapustin, Alexei/H-9924-2014 OI King, Michael/0000-0003-2645-7298; Gatebe, Charles/0000-0001-9261-2239; Lyapustin, Alexei/0000-0003-1105-5739 NR 45 TC 35 Z9 36 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1072 EP 1092 DI 10.1175/JAS3386.1 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000011 ER PT J AU Chowdhary, J Cairns, B Mishchenko, MI Hobbs, PV Cota, GF Redemann, J Rutledge, K Holben, BN Russell, E AF Chowdhary, J Cairns, B Mishchenko, MI Hobbs, PV Cota, GF Redemann, J Rutledge, K Holben, BN Russell, E TI Retrieval of aerosol scattering and absorption properties from photopolarimetric observations over the ocean during the CLAMS experiment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESEARCH SCANNING POLARIMETER; GROUND-BASED MEASUREMENTS; ATMOSPHERIC CORRECTION; SIZE DISTRIBUTION; SATELLITE RETRIEVAL; MULTIPLE-SCATTERING; OPTICAL-PROPERTIES; REFRACTIVE-INDEX; SULFATE AEROSOLS; LIGHT-SCATTERING AB The extensive set of measurements performed during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment provides a unique opportunity to evaluate aerosol retrievals over the ocean from multiangle, multispectral photometric, and polarimetric remote sensing observations by the airborne Research Scanning Polarimeter (RSP) instrument. Previous studies have shown the feasibility of retrieving particle size distributions and real refractive indices from such observations for visible wavelengths without prior knowledge of the ocean color. This work evaluates the fidelity of the aerosol retrievals using RSP measurements during the CLAMS experiment against aerosol properties derived from in situ measurements, sky radiance observations, and sun-photometer measurements, and further extends the scope of the RSP retrievals by using a priori information about the ocean color to constrain the aerosol absorption and vertical distribution. It is shown that the fine component of the aerosol observed on 17 July 2001 consisted predominantly of dirty sulfatelike particles with an extinction optical thickness of several tenths in the visible, an effective radius of 0.15 +/- 0.025 Am and a single scattering albedo of 0.91 +/- 0.03 at 550 nm. Analyses of the ocean color and sky radiance observations favor the lower boundary of aerosol single scattering albedo, while in situ measurements favor its upper boundary. Both analyses support the polarimetric retrievals of fine-aerosol effective radius and the consequent spectral variation in extinction optical depth. The estimated vertical distribution of this aerosol component depends on assumptions regarding the water-leaving radiances and is consistent with the top of the aerosol layer being close to the aircraft height (3500 m), with the bottom of the layer being between 2.7 km and the surface. The aerosol observed on 17 July 2001 also contained coarse-mode particles. Comparison of RSP data with sky radiance and in situ measurements suggests that this component consists of nonspherical particles with an effective radius in excess of I Am, and with the extinction optical depth being much less than one-tenth at 550 nm. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA USA. Bay Area Environm Res Inst, Sonoma, CA USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SpecTIR Corp, Santa Barbara, CA USA. RP Cairns, B (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM bc25@columbia.edu RI Mishchenko, Michael/D-4426-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 61 TC 57 Z9 58 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1093 EP 1117 DI 10.1175/JAS3389.1 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000012 ER PT J AU Smith, WL Zhou, DK Larar, AM Mango, SA Howell, HB Knuteson, RO Revercomb, HE Smith, WL AF Smith, WL Zhou, DK Larar, AM Mango, SA Howell, HB Knuteson, RO Revercomb, HE Smith, WL TI The NPOESS airborne sounding testbed interferometer - Remotely sensed surface and atmospheric conditions during CLAMS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NAST-I; TEMPERATURE; RETRIEVAL; PROFILES; VALIDATION; SATELLITES; ALGORITHM; AIRCRAFT; MOISTURE AB During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS), the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed-Interferometer (NAST-I), flying aboard the high-altitude Proteus aircraft, observed the spatial distribution of infrared radiance across the 650-2700 cm(-1) (3.7-15.4 mu m) spectral region with a spectral resolution of 0.25 cm(-1). NAST-I scans cross track with a moderate spatial resolution (a linear ground resolution equal to 13% of the aircraft altitude at nadir). The broad spectral coverage and high spectral resolution of this instrument provides abundant information about the surface and three-dimensional state of the atmosphere. In this paper, the NAST-I measurements and geophysical product retrieval methodology employed for CLAMS are described. Example results of surface properties and atmospheric temperature. water vapor, ozone, and carbon monoxide distributions are provided. The CLAMS NAST-I geophysical dataset is available for use by the scientific community. C1 Hampton Univ, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NPOESS Integrated Program Off, Silver Spring, MD USA. Univ Wisconsin, Madison, WI USA. RP Smith, WL (reprint author), Ctr Atmospher Sci, 23 Tyler St, Hampton, VA 23668 USA. EM bill.smith@hamptonu.edu; bill.smith@hamptonu.edu NR 25 TC 25 Z9 25 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1118 EP 1134 DI 10.1175/JAS3384.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000013 ER PT J AU Gu, GJ Adler, RF Sobel, AH AF Gu, GJ Adler, RF Sobel, AH TI The eastern Pacific ITCZ during the boreal spring SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SEA-SURFACE TEMPERATURE; INTERTROPICAL CONVERGENCE ZONE; TROPICAL PACIFIC; ANNUAL CYCLE; EQUATORIAL CONVECTION; SATELLITE; PRECIPITATION; SCATTEROMETER; CIRCULATION; WIND AB The 6-yr (1998-2003) rainfall products from the Tropical Rainfall Measuring Mission (TRMM) are used to quantify the intertropical convergence zone (ITCZ) in the eastern Pacific (defined by longitudinal averages over 90 degrees-130 degrees W) during boreal spring (March-April). The double-ITCZ phenomenon, represented by the occurrence of two maxima with respect to latitude in monthly mean rainfall, is observed in most but not all of the years studied. The relative spatial locations of maxima in sea surface temperature (SST), rainfall, and surface pressure are examined. Interannual and weekly variability are characterized in SST, rainfall, surface convergence, total column water vapor, and cloud water. There appears to be a competition for rainfall between the two hemispheres during this season. When one of the two rainfall maxima is particularly strong, the other tends to be weak, with the total rainfall integrated over the two varying less than does the difference between the rainfall integrated over each separately. There is some evidence for a similar competition between the SST maxima in the two hemispheres, but this is more ambiguous, and there is evidence that some variations in the relative strengths of the two rainfall maxima may be independent of SST. Using a 25-yr (1979-2003) monthly rainfall dataset from the Global Precipitation Climatology Project (GPCP), four distinct ITCZ types during March-April are defined, based on the relative strengths of rainfall peaks north and south of, and right over, the equator. Composite meridional profiles and spatial distributions of rainfall and SST are documented for each type. Consistent with previous studies, an equatorial cold tongue is essential to the existence of the double ITCZs. However, too strong a cold tongue may dampen either the southern or northern rainfall maximum, depending on the magnitude of SST north of the equator. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY USA. RP Gu, GJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. EM ggu@agnes.gsfc.nasa.gov RI Sobel, Adam/K-4014-2015 OI Sobel, Adam/0000-0003-3602-0567 NR 33 TC 21 Z9 21 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1157 EP 1174 DI 10.1175/JAS3402.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000015 ER PT J AU Xu, KM AF Xu, KM TI The sensitivity of diagnostic radiative properties to cloud microphysics among cloud-resolving model simulations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CIRRUS CLOUDS; ACCURATE PARAMETERIZATION; SATELLITE-OBSERVATIONS; CUMULUS ENSEMBLES; CLIMATE MODELS; ECMWF MODEL; CONVECTION; RADAR; VALIDATION; DYNAMICS AB This study examines the sensitivity of diagnosed radiative fluxes and heating rates to different treatments of cloud microphysics among cloud-resolving models (CRMs). The domain-averaged CRM outputs are used in this calculation. The impacts of the cloud overlap and uniform hydrometeor assumptions are examined using outputs having spatially varying cloud fields from a single CRM. It is found that the cloud overlap assumption impacts the diagnosis more significantly than the uniform hydrometeor assumption for all radiative fluxes. This is also the case for the longwave radiative cooling rate except for a layer above 7 km where it is more significantly impacted by the uniform hydrometeor assumption. The radiative cooling above upper-tropospheric anvils and the warming below these clouds are overestimated by about 0.5 K day(-1) using the domain-averaged outputs. These results are used to further quantify intermodel differences in radiative properties due to different treatments of cloud microphysics among 10 CRMs. The magnitudes of the intermodel differences, as measured by the deviations from the consensus of 10 CRMs, are found to be smaller than those due to the cloud overlap assumption and comparable to those due to the uniform hydrometeor assumption for most shortwave radiative fluxes and the net radiative fluxes at the top of the atmosphere (TOA) and at the surface. For all longwave radiative fluxes, they are smaller than those due to cloud overlap and uniform hydrometeor assumptions. The consensus of all diagnosed radiative fluxes except for the surface downward shortwave flux agrees with observations to a degree that is close to the uncertainties of satellite- and ground-based measurements. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Xu, KM (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM Kuan-Man.Xu@nasa.gov RI Xu, Kuan-Man/B-7557-2013 OI Xu, Kuan-Man/0000-0001-7851-2629 NR 39 TC 6 Z9 6 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR PY 2005 VL 62 IS 4 BP 1241 EP 1254 DI 10.1175/JAS3401.1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 918EL UT WOS:000228525000020 ER PT J AU Shu, Y Li, BQ de Groh, HC AF Shu, Y Li, BQ de Groh, HC TI Convection and solidification in constant and oscillating thermal gradients: Measurements and simulations SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID BENARD CONVECTION; BINARY MIXTURE; CRYSTAL-GROWTH; ALLOY; INTERFACE; PATTERN; CAVITY; FIELDS; FLOWS; PB AB An experimental and numerical study of natural convection and solidification in a two-dimensional cavity driven by constant and oscillating temperature gradients is presented. Finite element models are developed to predict the flowfield, the temperature distribution, and the solid-liquid interphase shapes during solidification. Both the fixed-grid and moving-grid methods are applied in the numerical simulations, using the former to illustrate the oscillating thermal gradient conditions and using the latter to illustrate the constant temperature gradient conditions. An experimental system is set up where succinonitrile is used as a working fluid. The flow pattern, the velocity field, and the solidification interface shape are measured using the laser-based particle-image-velocimetry system. Numerical simulations and experiments are conducted for various configurations and different thermal gradients. In most cases, convection is dominated by one recirculating loop. With an inverted temperature gradient, however, multiple convection loops are observed. Both the convective How pattern and the velocity strongly affect the solid-liquid interface shapes during solidification. In a majority of the cases studied, the model predictions are in good agreement with the experimental measurements. C1 Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99163 USA. NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Shu, Y (reprint author), Washington State Univ, Sch Mech & Mat Engn, Pullman, WA 99163 USA. EM li@mme.wsu.edu NR 26 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 2005 VL 19 IS 2 BP 199 EP 208 DI 10.2514/1.8809 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 916UR UT WOS:000228412200009 ER PT J AU Amador, JJ AF Amador, JJ TI Markov random field approach to region extraction using Tabu Search SO JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION LA English DT Article DE Markov random field; Gibbs distribution; Tabu Search; region extraction ID IMAGE INTERPRETATION; HEURISTICS; MODELS AB This paper describes a region extraction algorithm based on the concept of Markov random fields. Markov random fields (MRFs) are characterized by using a Gibbs Distribution which equates back to the MRF. A heuristically developed energy functional is presented and used with the MRF in an efficient and accurate manner. Since the MRF used in this work is defined using the polar coordinate system, a very large search space exists for radial lengths and sites. To aid in pursuing these radial sites, a combinatorial optimization technique known as Tabu Search is exploited. Also provided is an extensive empirical study on aerial imagery and parts detection, in addition to a final discussion and description of future work. (c) 2004 Elsevier Inc. All rights reserved. C1 John F Kennedy Space Ctr, NASA, Kennedy Space Ctr, FL 32899 USA. RP Amador, JJ (reprint author), John F Kennedy Space Ctr, NASA, Kennedy Space Ctr, FL 32899 USA. EM Jose.J.Amador@nasa.gov NR 30 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1047-3203 J9 J VIS COMMUN IMAGE R JI J. Vis. Commun. Image Represent. PD APR PY 2005 VL 16 IS 2 BP 134 EP 158 DI 10.1016/j.vcir.2004.06.002 PG 25 WC Computer Science, Information Systems; Computer Science, Software Engineering SC Computer Science GA 915VY UT WOS:000228340700002 ER PT J AU Zhang, Y Liu, XW Liu, Y Rubin, RH AF Zhang, Y Liu, XW Liu, Y Rubin, RH TI Helium recombination spectra as temperature diagnostics for planetary nebulae SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM : general; planetary nebulae : general ID HEAVY ELEMENT LINES; CHEMICAL ABUNDANCES; ELECTRON-TEMPERATURE; PHYSICAL CONDITIONS; DENSITY VARIATIONS; EMISSION-LINES; DEEP SURVEY; FLUCTUATIONS; PLASMA AB Electron temperatures derived from the He I recombination line ratios, designated T-e( He I), are presented for 48 planetary nebulae (PNe). We study the effect that temperature fluctuations inside nebulae have on the T-e(He I) value. We show that a comparison between T-e(He I) and the electron temperature derived from the Balmer jump of the HI recombination spectrum, designated T-e(H I), provides an opportunity to discriminate between the paradigms of a chemically homogeneous plasma with temperature and density variations, and a two-abundance nebular model with hydrogen-deficient material embedded in diffuse gas of a 'normal' chemical composition (i.e. solar), as the possible causes of the dichotomy between the abundances that are deduced from collisionally excited lines and those deduced from recombination lines. We find that T-e( He I) values are significantly lower than T-e(H I) values, with an average difference of < T-e(H I) - T-e(He I)> = 4000 K. The result is consistent with the expectation of the two-abundance nebular model but is opposite to the prediction of the scenarios of temperature fluctuations and/or density inhomogeneities. From the observed difference between T-e(He I) and T-e(H I), we estimate that the filling factor of hydrogen-deficient components has a typical value of 10(-4). In spite of its small mass, the existence of hydrogen-deficient inclusions may potentially have a profound effect in enhancing the intensities of He I recombination lines and thereby lead to apparently overestimated helium abundances for PNe. C1 Peking Univ, Dept Astron, Beijing 100871, Peoples R China. Guangzhou Univ, Dept Phys, Guangzhou 510405, Peoples R China. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zhang, Y (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM zhangy@stsci.edu NR 34 TC 30 Z9 30 U1 0 U2 1 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 2005 VL 358 IS 2 BP 457 EP 467 DI 10.1111/j.1365-2966.2005.08810.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 906VZ UT WOS:000227673700012 ER PT J AU Banks, HT Gibson, NL Winfree, WP AF Banks, HT Gibson, NL Winfree, WP TI Gap detection with electromagnetic terahertz signals SO NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS LA English DT Article DE electromagnetic interrogation; dielectrics; terahertz; nonlinear optimization AB We apply an inverse problem formulation to determine characteristics of a defect from a perturbed electromagnetic interrogating signal. A defect (gap) inside of a dielectric material causes a disruption, via reflections and refractions at the material interfaces, of the windowed interrogating signal. We model the electromagnetic waves inside the material with Maxwell's equations. This leads to a non-standard, nonlinear optimization problem for the dimensions and location of the defect. Using simulations as forward solves, we employ a Newton-based, iterative optimization scheme to a novel modified least-squares objective function. Numerical results are given in tables and plots, standard errors are calculated, and computational issues are addressed. (C) 2004 Elsevier Ltd. All rights reserved. C1 N Carolina State Univ, Ctr Res & Sci Computat, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Banks, HT (reprint author), N Carolina State Univ, Ctr Res & Sci Computat, Box 8205, Raleigh, NC 27695 USA. EM htbanks@eos.ncsu.edu NR 7 TC 9 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1468-1218 J9 NONLINEAR ANAL-REAL JI Nonlinear Anal.-Real World Appl. PD APR PY 2005 VL 6 IS 2 BP 381 EP 416 DI 10.1016/j.nonrwa.2004.09.004 PG 36 WC Mathematics, Applied SC Mathematics GA 889HC UT WOS:000226433100009 ER PT J AU Kanbach, G Andritschke, R Zoglauer, A Ajello, M McConnell, ML Macri, JR Ryan, JM Bloser, P Hunter, S DiCocco, G Kurfess, J Reglero, V AF Kanbach, G Andritschke, R Zoglauer, A Ajello, M McConnell, ML Macri, JR Ryan, JM Bloser, P Hunter, S DiCocco, G Kurfess, J Reglero, V TI Development and calibration of the tracking Compton/Pair telescope MEGA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Symposium on Development and Application of Semiconductor Tracking Detectors CY JUN 14-17, 2004 CL Hiroshima, JAPAN SP Hiroshima Univ, Fac Sci DE DSSD tracking detector; CsI/PIN diode calorimeter; Compton telescope; gamma-ray astronomy; medium gamma-ray energies; MEGA ID GAMMA-RAY TELESCOPE; MISSION AB We describe the development and tests of the prototype for a new telescope for Medium Energy Gamma-ray Astronomy (MEGA) in the energy band 0.4-50 MeV. As a successor to COMPTEL and EGRET (at low energies), MEGA aims to improve the sensitivity for astronomical sources by at least an order of magnitude. It could thus fill the severe sensitivity gap between scheduled or operating hard-X-ray and high-energy gamma-ray missions and open the way for a future Advanced Compton Telescope. MEGA records and images gamma-rays by completely tracking Compton and Pair creation events in a stack of double-sided Si-strip track detectors surrounded by a pixelated CsI calorimeter. A scaled down prototype has been built and we describe technical details of its design and properties. Results from calibrations using radioactive sources and from measurements with an accelerator generated, fully polarized, gamma-ray beam are presented and an outlook to future plans with MEGA is given. (c) 2005 Elsevier B.V. All rights reserved. C1 Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Univ New Hampshire, Ctr Space Sci, Durham, NC USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, IASF, I-40126 Bologna, Italy. USN, Res Lab, Washington, DC 20350 USA. Univ Valencia, GACE, E-46003 Valencia, Spain. RP Kanbach, G (reprint author), Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. EM gok@mpe.mpg.de RI Hunter, Stanley/D-2942-2012 NR 18 TC 35 Z9 35 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 2005 VL 541 IS 1-2 BP 310 EP 322 DI 10.1016/j.nima.2005.01.071 PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 919LX UT WOS:000228620600041 ER PT J AU Sato, G Parsons, A Hullinger, D Suzuki, M Takahashi, T Tashiro, M Nakazawa, K Okada, Y Takahashi, H Watanabe, S Barthelmy, S Cummings, J Gehrels, N Krimm, H Markwardt, C Tueller, J Fenimore, E Palmer, D AF Sato, G Parsons, A Hullinger, D Suzuki, M Takahashi, T Tashiro, M Nakazawa, K Okada, Y Takahashi, H Watanabe, S Barthelmy, S Cummings, J Gehrels, N Krimm, H Markwardt, C Tueller, J Fenimore, E Palmer, D TI Development of a spectral model based on charge transport for the Swift/BAT 32K CdZnTe detector array SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Symposium on Development and Application of Semiconductor Tracking Detectors CY JUN 14-17, 2004 CL Hiroshima, JAPAN SP Hiroshima Univ, Fac Sci DE gamma-ray astronomy; swift; BAT; CdZnTe; mobility-lifetime products; spectral model ID CDTE AB The properties of 32K CdZnTe (4 x 4 mm(2) large, 2 rum thick) detectors have been studied in the pre-flight calibration of the Burst Alert Telescope (BAT) on-board the Swift Gamma-ray Burst Explorer (scheduled for launch in November 2004). In order to understand the energy response of the BAT CdZnTe array, we first quantify the mobility-lifetime (mu tau) products of carriers in individual CdZnTe detectors, which produce a position dependency in the charge induction efficiency and results in a low-energy tail in the energy spectrum. Based on a new method utilizing Co-57 spectra obtained at different bias voltages, the mu tau for electrons ranges from 5.0 x 10(-4) to 1.0 x 10(-2) cm(2) V-1 while the mu tau for holes ranges from 1.3 x 10(-5) to 1.8 x 10(-4) cm(2) V-1. We find that this wide distribution of mu tau products explains the large diversity in spectral shapes between CdZnTe detectors well. We also find that the variation of mu tau products can be attributed to the difference of crystal ingots or manufacturing harness. We utilize the 32K sets of extracted mu tau products to develop a spectral model of the detector. In combination with Monte Carlo simulations, we can construct a spectral model for any photon energy or any incident angle. (c) 2005 Elsevier B.V. All rights reserved. C1 JAXA, ISAS, Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Univ Tokyo, Bunkyo Ku, Tokyo 1130033, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Saitama Univ, Sakura, Saitama 3388570, Japan. Univ Space Res Assoc, Seabrook, MD USA. Los Alamos Natl Lab, Los Alamos, NM USA. RP Sato, G (reprint author), JAXA, ISAS, Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Kanagawa 2298510, Japan. EM gsato@astro.isas.jaxa.jp RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; Parsons, Ann/I-6604-2012; Tashiro, Makoto/J-4562-2012 NR 12 TC 24 Z9 24 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 2005 VL 541 IS 1-2 BP 372 EP 384 DI 10.1016/j.nima.2005.01.078 PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 919LX UT WOS:000228620600048 ER PT J AU Dahlback, A Eide, HA Hoiskar, BAK Olsen, RO Schmidlin, F Tsay, SC Stamnes, K AF Dahlback, A Eide, HA Hoiskar, BAK Olsen, RO Schmidlin, F Tsay, SC Stamnes, K TI Comparison of data for ozone amounts and ultraviolet doses obtained from simultaneous measurements with various standard ultraviolet instruments SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on UV Ground- and Space-based Measurements, Models and Effects III CY AUG 04-06, 2003 CL San Diego, CA SP SPIE DE filter instruments; Dobson; Brewer; total ozone mapping spectrometer; ozone measurements; ultraviolet radiation; clouds ID RADIATION; FILTER AB Recent technological advances have made measurements of UV doses and ozone column amounts with multichannel filter instruments not only possible, but also an attractive alternative to other more labor-intensive and weather-dependent methods. Filter instruments can operate unattended for long periods of time, and it is possible to obtain accurate ozone column amounts even on cloudy days. We present results from extensive comparisons of the performance of several Norwegian Institute for Air Research UV (NILU-UV) and ground-based (GUV) filter instruments against Dobson and Brewer instruments and the earth probe-total ozone mapping spectrometer (EP-TOMS) instrument. The data used in the comparisons are from four different sites where we have had the opportunity to operate more than one type of UV instrument for extended periods of time. The sites include the University of Oslo, Norway; Ny-Alesund, Spitzbergen, Norway; the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center facilities at Wallops Island, Virginia, and Greenbelt, Maryland; and the University of Alaska, Fairbanks. Our results show that ozone column amounts obtained With current filter-type instruments have an accuracy similar to those obtained with the Dobson instrument. The mean difference between NILU-UV and Dobson direct sun measurements were 0.4 +/- 11.9% (1 sigma) in Oslo for the period 2000 to 2003. The difference between a GUV and the same Dobson was 1.7 +/- 1.4% for the same time period. The mean difference between GUV and TOMS in Ny-Alesund 79 deg N and Oslo 60 deg N in the period 1996 to 1999 was <0.5 +/- 3% for days with noon solar zenith angles (SZAs)<80 deg. (c) 200 5 society of Photo-optical Instrumentation Engineers. C1 Univ Oslo, Dept Phys, N-0316 Oslo, Norway. Stevens Inst Technol, Dept Phys & Engn Phys, Hoboken, NJ 07030 USA. Norwegian Inst Air Res, N-2007 Kjeller, Norway. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Observ Sci Branch, Wallops Isl, VA 23337 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Dahlback, A (reprint author), Univ Oslo, Dept Phys, POB 1048, N-0316 Oslo, Norway. EM Arne.Dahlback@fys.uio.no NR 10 TC 7 Z9 7 U1 0 U2 1 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 2005 VL 44 IS 4 AR 041010 DI 10.1117/1.1885473 PG 9 WC Optics SC Optics GA 974KN UT WOS:000232590400015 ER PT J AU Krotkov, N Bhartia, PK Herman, J Slusser, J Scott, G Labow, G Vasilkov, AP Eck, TF Dubovik, O Holben, BN AF Krotkov, N Bhartia, PK Herman, J Slusser, J Scott, G Labow, G Vasilkov, AP Eck, TF Dubovik, O Holben, BN TI Aerosol ultraviolet absorption experiment (2002 to 2004), part 2: absorption optical thickness, refractive index, and single scattering albedo SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on UV Ground- and Space-based Measurements, Models and Effects III CY AUG 04-06, 2003 CL San Diego, CA SP SPIE DE ultraviolet radiation; aerosol absorption; single scattering albedo; CIMEL sunphotometer; AERONET network; ultraviolet multifilter rotating shadow-band radiometer; diffuse fraction measurements ID SKY RADIANCE MEASUREMENTS; SURFACE UV IRRADIANCE; RADIATIVE-TRANSFER; LIGHT-ABSORPTION; WAVELENGTH DEPENDENCE; ATMOSPHERIC DUST; PHOTOLYSIS RATES; GROUND ALBEDO; DESERT DUST; B RADIATION AB Compared to the visible spectral region, very little is known about aerosol absorption in the UV. Without such information it is impossible to quantify the causes of the observed discrepancy between modeled and measured UV irradiances and photolysis rates. We report results of a 17-month aerosol column absorption monitoring experiment conducted in Greenbelt, Maryland, where the imaginary part of effective refractive index k was inferred from the measurements of direct and diffuse atmospheric transmittances by a UV-multifilter rotating shadow-band radiometer [UV-MFRSR, U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Network]. Colocated ancillary measurements of aerosol effective particle size distribution and refractive index in the visible wavelengths [by CIMEL sun-sky radiometers, National Aeronautics and Space Administration (NASA) Aerosol Robotic Network (AERONET)], column ozone, surface pressure, and albedo constrain the forward radiative transfer model input, so that a unique solution for k is obtained independently in each UV-MFRSR spectral channel. Inferred values of k are systematically larger in the UV than in the visible wavelengths. The inferred k values enable calculation of the single scattering albedo omega, which is compared with AERONET inversions in the visible wavelengths. On cloud-free days with high aerosol loadings [tau(ext)(440) >0.4], omega is systematically lower at 368 nm (=0.94) than at 440 nm (=0.96), however, the mean omega differences (0.02) are within expected uncertainties of omega retrievals (similar to 0.03). The inferred omega is even ;lower at shorter UV wavelengths ()similar to =0.92), which might suggest the presence of selectively UV absorbing aerosols. We also find that a) decreases with decrease in aerosol loading. This could be due to real changes in the average aerosol composition between summer and winter months at the Goddard Space Flight Center (GSFC) site. Combing measurements of tau(ext) and w, the seasonal dependence of the aerosol absorption optical thickness, tau(rbs)=tau(ext)(1 - omega) is derived in the UV with an uncertainty of 0.01 to 0.02, limited by the accuracy of UV-MFRSR measurement and calibration. The tau(abs) has a pronounced seasonal dependence with maximum values similar to 0.1 occurring in summer hazy conditions and <0.02 in the winter and fall seasons, when aerosol loadings are small. The measured tau(abs) is sufficient to explain both the magnitude and seasonal dependence of the bias in satellite estimates of surface UV irradiance previously seen with ground-based UV measurements. (c) 2005 Society of Photo-Optical Instrumentation Engineers. C1 Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Colorado State Univ, Nat Resources Ecol Lab, USDA, UV B Monitoring & Res Network, Ft Collins, CO 80523 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Krotkov, N (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM Krotkov@chescat.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; ECK, THOMAS/D-7407-2012; Krotkov, Nickolay/E-1541-2012; Bhartia, Pawan/A-4209-2016; OI Dubovik, Oleg/0000-0003-3482-6460; Krotkov, Nickolay/0000-0001-6170-6750; Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632 NR 55 TC 36 Z9 36 U1 1 U2 10 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 2005 VL 44 IS 4 AR 041005 DI 10.1117/1.1886819 PG 17 WC Optics SC Optics GA 974KN UT WOS:000232590400010 ER PT J AU Krotkov, N Bhartia, PK Herman, J Slusser, J Labow, G Scott, G Janson, G Eck, TF Holben, B AF Krotkov, N Bhartia, PK Herman, J Slusser, J Labow, G Scott, G Janson, G Eck, TF Holben, B TI Aerosol ultraviolet absorption experiment (2002 to 2004), part 1: ultraviolet multifilter rotating shadowband radiometer calibration and intercomparison with CIMEL sunphotometers SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on UV Ground- and Space-based Measurements, Models and Effects III CY AUG 04-06, 2003 CL San Diego, CA SP SPIE DE ultraviolet radiation; aerosol absorption; CIMEL sunphotometer; AERONET network; ultraviolet multifilter rotating shadowband radiometer; diffuse fraction measurements; Langley calibration ID SINGLE SCATTERING ALBEDO; SURFACE UV IRRADIANCE; OPTICAL DEPTH; LIGHT-ABSORPTION; BAND RADIOMETER; DOBSON SPECTROPHOTOMETERS; WAVELENGTH DEPENDENCE; RADIATIVE PROPERTIES; FILTER RADIOMETERS; COSINE RESPONSE AB Radiative transfer calculations of UV irradiance from total ozone mapping spectrometer (TOMS) satellite data are frequently overestimated compared to ground-based measurements because of the presence of undetected absorbing aerosols in the planetary boundary layer. To reduce these uncertainties, an aerosol UV absorption closure experiment has been conducted at the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) site in Greenbelt, Maryland, using 17 months of data from a shadowband radiometer [UV-multifilter rotating shadowband radiometer (UV-MFRSR), U.S. Department of Agriculture (USDA) UV-B Monitoring and Research Network] colocated with a group of three sun-sky CIMEL radiometers [rotating reference instruments of the NASA Aerosol Robotic Network (AERONET)]. We describe an improved UV-MFRSR on-site calibration method augmented by AERONET-CIMEL measurements of aerosol extinction optical thickness (tau(a)) interpolated or extrapolated to the UV-MFRSR wavelengths and measurement intervals. The estimated tau(a) is used as input to a UV-MFRSR spectral-band model, along with independent column ozone and surface pressure measurements, to estimate zero air mass voltages V-0 in three longer wavelength UV-MFRSR channels (325, 332, 368 nm). Daily mean < V-0> estimates and standard deviations are obtained for cloud-free conditions and compared with the on-site UV-MFRSR Langley plot calibration method. By repeating the calibrations on clear days, relatively good stability (+/- 2% in < V-0>) is found in summer, with larger relative changes in fall-winter seasons. The changes include systematic day-to-day < V-0> decline for extended periods along with step jump changes after major precipitation periods (rain or snow) that affected the diffuser transmission. When daily V-0 values are used to calculate 7, for individual 3-min UV-MFRSR measurements on the same days, the results compare well with interpolated AERONET tau(a), measurements [at 368 nm most daily 1 sigma root mean square (rms) differences were within 0.01]. When intercalibrated against an AERONET sunphotometer, the UV-MFRSR is proven reliable to retrieve tau(a) and hence can be used to retrieve aerosol column absorption in the UV. The advantage of the shadowband technique is that the calibration obtained for direct-sun voltage can then be applied to diffuse-radiance voltage to obtain total and diffuse atmospheric transmittances. These transmittances, in combination with accurate tau(a) data, provide the basis for estimating aerosol column absorption at many locations of the USDA UV-B Monitoring and Research network and for correction of satellite estimations of surface UV irradiance. (c) 2005 Society of Photo-Optical Instrumentation Engineers. C1 Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Colorado State Univ, Nat Resources Ecol Lab, USDA, UV B Monitoring & Res Network, Ft Collins, CO 80523 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Krotkov, N (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM Krotkov@chescat.gsfc.nasa.gov RI ECK, THOMAS/D-7407-2012; Krotkov, Nickolay/E-1541-2012; Bhartia, Pawan/A-4209-2016; OI Krotkov, Nickolay/0000-0001-6170-6750; Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632 NR 48 TC 16 Z9 17 U1 0 U2 4 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 2005 VL 44 IS 4 AR 041004 DI 10.1117/1.1886818 PG 17 WC Optics SC Optics GA 974KN UT WOS:000232590400009 ER PT J AU Slusser, J Gao, W Herman, JR AF Slusser, J Gao, W Herman, JR TI Advances in UV ground- and space-based measurements and modeling II SO OPTICAL ENGINEERING LA English DT Editorial Material C1 Colorado State Univ, Nat Resource Ecol Lab, UV B Monitoring & Res Program, Ft Collins, CO 80523 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Colorado State Univ, Nat Resource Ecol Lab, UV B Monitoring & Res Program, Ft Collins, CO 80523 USA. EM sluss@uvb.nrel.colostate.edu RI Gao, Wei/C-1430-2016 NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD APR PY 2005 VL 44 IS 4 AR 041001 DI 10.1117/1.1885026 PG 2 WC Optics SC Optics GA 974KN UT WOS:000232590400006 ER PT J AU Tian, JL AF Tian, JL TI Reconstruction of irregularly sampled interferograms in Fourier transform spectrometry with unknown sampling locations SO OPTICAL ENGINEERING LA English DT Article DE Fourier transform spectrometry; spectrometer; interferograms; nonuniform sampling; irregular sampling; reconstruction; evolutionary algorithms AB We propose an algorithm for reconstructing nonuniformly sampled interferograms when sampling locations are unknown. An optimization problem with multiple objective and constraint functions is designed based on the spatial and spectral characteristics of the data measurement. This problem is solved using an evolutionary approach, in which potential solutions are competing to be the fittest individual in a simulated natural environment. (c) 2005 Society of Photo-Optical Instrumentation Engineers. C1 NASA, Langley Res Ctr, Sci Appl Int Corp, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. RP Tian, JL (reprint author), NASA, Langley Res Ctr, Sci Appl Int Corp, Mail Stop 468, Hampton, VA 23681 USA. EM j.tian@larc.nasa.gov NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 2005 VL 44 IS 4 AR 048201 DI 10.1117/1.1882355 PG 8 WC Optics SC Optics GA 974KN UT WOS:000232590400042 ER PT J AU Strekalov, D Matsko, AB Savchenkov, AA Maleki, L AF Strekalov, D Matsko, AB Savchenkov, AA Maleki, L TI Relationship between quantum two-photon correlation and classical spectrum of light SO PHYSICAL REVIEW A LA English DT Article ID EMISSION; DISPERSION AB We show that the two-photon temporal (longitudinal) correlation of light is limited by its classical optical spectral width. We present examples of the sources of two-photon light approaching this limit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Strekalov, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 17 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2005 VL 71 IS 4 AR 041803 DI 10.1103/PhysRevA.71.041803 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 921GR UT WOS:000228752700010 ER PT J AU Chui, T Penanen, K AF Chui, T Penanen, K TI Frequency-dependent hydrodynamic inductance and the determination of the thermal and quantum noise of a superfluid gyroscope SO PHYSICAL REVIEW B LA English DT Article ID HE-3 AB We reexamine mass flow in a superfluid gyroscope containing a superfluid Josephson weak link. We introduce a frequency-dependent hydrodynamic inductance to account for an oscillatory flow of the normal fluid component in the sensing loop. With this hydrodynamic inductance, we derive the thermal phase noise, and hence the thermal rotational noise of the gyroscope. We examine the thermodynamic stability of the system based on an analysis of the free energy. We derive a quantum phase noise, which is analogous to the zero-point motion of a simple harmonic oscillator. The configuration of the studied gyroscope is analogous to a conventional superconducting RF SQUID. We show that the gyroscope has very low intrinsic noise (1.9x10(-13) rad s(-1)/root Hz), and it can potentially be applied to study general relativity, Earth science, and to improve global positioning systems (GPS). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chui, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 7 Z9 7 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR PY 2005 VL 71 IS 13 AR 132509 DI 10.1103/PhysRevB.71.132509 PG 4 WC Physics, Condensed Matter SC Physics GA 921JZ UT WOS:000228761800019 ER PT J AU Garces, JE Bozzolo, G AF Garces, JE Bozzolo, G TI Determination of structural alloy equilibrium properties from quantum approximate methods SO PHYSICAL REVIEW B LA English DT Article ID THERMODYNAMIC PROPERTIES; INTERMETALLIC COMPOUNDS; PHASE-DIAGRAM; TI; ENTHALPIES; SYSTEMS; METAL; ALUMINIDES; STABILITY; NITI AB In this paper we address basic issues, not investigated previously, concerning the relationship between ab initio methods and the Bozzolo-Ferrante-Smith (BFS) method for alloys, and its ability to model the process of alloy formation and reproduce structural alloy properties near and at equilibrium. Based on perturbation theory, the method requires single element parameters and their binary combinations, even for multicomponent systems. A direct comparison of BFS predictions of equilibrium alloy properties against ab initio results, and the handling and influence of the parameterization on the accuracy with which the method reproduces the process of alloy formation are presented. Besides establishing a range of validity for the method in reference to first-principles results, a simple algorithm for the determination of equilibrium properties of ordered alloy systems is introduced and illustrated with applications to binary and higher order systems, maximizing the flow of information carried in the first-principles-based parameters. C1 Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. Ohio Aerosp Inst, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Garces, JE (reprint author), Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. NR 33 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR PY 2005 VL 71 IS 13 AR 134201 DI 10.1103/PhysRevB.71.134201 PG 10 WC Physics, Condensed Matter SC Physics GA 921JZ UT WOS:000228761800035 ER PT J AU Mehrez, H Svizhenko, A Anantram, MP Elstner, M Frauenheim, T AF Mehrez, H Svizhenko, A Anantram, MP Elstner, M Frauenheim, T TI Analysis of band-gap formation in squashed armchair carbon nanotubes SO PHYSICAL REVIEW B LA English DT Article ID TIGHT-BINDING METHOD; SIMULATIONS AB The electronic properties of deformed armchair carbon nanotubes are modeled using constraint free density functional tight binding molecular dynamics simulations. Independent from CNT diameter, deforming path can be divided into three regimes. In the first regime, the nanotube deforms with negligible force. In the second one, there is significantly more resistance to deforming with the force being similar to 40-100 nN/per CNT unit cell. In the last regime, the CNT loses its hexagonal structure resulting in force drop-off followed by substantial force enhancement upon deforming. We compute the change in band gap as a function of deforming and our main results are: (i) A band gap initially opens due to interaction between atoms at the top and bottom sides of CNT. The pi-orbital approximation is successful in modeling the band-gap opening at this stage. (ii) In the second regime of deforming, large pi-sigma interaction at the edges becomes important, which can lead to band-gap oscillation. (iii) Contrary to a common perception, nanotubes with broken mirror symmetry can have zero band gap. (iv) All armchair nanotubes become metallic in the third regime of deforming. Finally, we discuss both differences and similarities obtained from the tight binding and density functional approaches. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, NASA Adv Supercomp Div, Moffett Field, CA 94035 USA. Univ Paderborn, D-33098 Paderborn, Germany. RP NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 229-1,Moffett Field, Moffett Field, CA 94035 USA. RI Elstner, Marcus/H-3463-2013; Frauenheim, Thomas/C-5653-2015 OI Frauenheim, Thomas/0000-0002-3073-0616 NR 22 TC 32 Z9 32 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR PY 2005 VL 71 IS 15 AR 155421 DI 10.1103/PhysRevB.71.155421 PG 7 WC Physics, Condensed Matter SC Physics GA 921KJ UT WOS:000228762900116 ER PT J AU Zhigilei, LV Wei, C Srivastava, D AF Zhigilei, LV Wei, C Srivastava, D TI Mesoscopic model for dynamic simulations of carbon nanotubes SO PHYSICAL REVIEW B LA English DT Article ID MECHANICAL-PROPERTIES; POLYMER COMPOSITES; LASER-ABLATION; CONTINUUM; NANOSTRUCTURES; STRENGTH; SCIENCE; STRAIN AB A mesoscopic model is developed for static and dynamic simulations of nanomechanics of carbon nanotubes (CNTs). The model is based on a coarse-grained representation of CNTs as "breathing flexible cylinders" consisting of a variable number of segments. Internal interactions within a CNT are described by a mesoscopic force field designed and parameterized based on the results of atomic-level molecular dynamics simulations. The radial size of the CNTs and external interactions among multiple CNTs and molecular matrix are introduced through a computationally efficient "virtual surface" method that does not require explicit representation of the CNT's surfaces. The mesoscopic model is shown to reproduce well the dynamic behavior of individual CNTs predicted in atomistic simulations at a minor fraction of the computational cost. C1 Univ Virginia, Dept Mat Sci & Engn, Charlottesville, VA 22904 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zhigilei, LV (reprint author), Univ Virginia, Dept Mat Sci & Engn, 116 Engineers Way, Charlottesville, VA 22904 USA. EM lz2n@virginia.edu; cwei@nas.nasa.gov; deepak@nas.nasa.gov RI Zhigilei, Leonid/E-2167-2012 NR 35 TC 40 Z9 40 U1 1 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR PY 2005 VL 71 IS 16 AR 165417 DI 10.1103/PhysRevB.71.165417 PG 12 WC Physics, Condensed Matter SC Physics GA 921KL UT WOS:000228763100103 ER PT J AU Ando, M Arai, K Aso, Y Beyersdorf, P Hayama, K Iida, Y Kanda, N Kawamura, S Kondo, K Mio, N Miyoki, S Moriwaki, S Nagano, S Numata, K Sato, S Somiya, K Tagoshi, H Takahashi, H Takahashi, R Tatsumi, D Tsunesada, Y Zhu, ZH Akutsu, T Akutsu, T Araya, A Asada, H Barton, MA Fujiki, Y Fujimoto, MK Fujita, R Fukushima, M Futamase, T Hamuro, Y Haruyama, T Hayakawa, H Heinzel, G Horikoshi, G Iguchi, H Ioka, K Ishitsuka, H Kamikubota, N Kaneyama, T Karasawa, Y Kasahara, K Kasai, T Katsuki, M Kawabe, K Kawamura, M Kawashima, N Kawazoe, F Kojima, Y Kokeyama, K Kozai, Y Kudoh, H Kuroda, K Kuwabara, T Matsuda, N Miura, K Miyakawa, O Miyama, S Mizusawa, H Musha, M Nagayama, Y Nakagawa, K Nakamura, T Nakano, H Nakao, K Nishi, Y Ogawa, Y Ohashi, M Ohishi, N Okutomi, A Oohara, K Otsuka, S Saito, Y Sakata, S Sasaki, M Sato, K Sato, N Sato, Y Seki, H Sekido, A Seto, N Shibata, M Shinkai, H Shintomi, T Soida, K Suzuki, T Takamori, A Takemoto, S Takeno, K Tanaka, T Taniguchi, K Taniguchi, S Tanji, T Taylor, CT Telada, S Tochikubo, K Tokunari, M Tomaru, T Tsubono, K Tsuda, N Uchiyama, T Ueda, A Ueda, K Usui, F Waseda, K Watanabe, Y Yakura, H Yamamoto, A Yamamoto, K Yamazaki, T Yanagi, Y Yoda, T Yokoyama, J Yoshida, T AF Ando, M Arai, K Aso, Y Beyersdorf, P Hayama, K Iida, Y Kanda, N Kawamura, S Kondo, K Mio, N Miyoki, S Moriwaki, S Nagano, S Numata, K Sato, S Somiya, K Tagoshi, H Takahashi, H Takahashi, R Tatsumi, D Tsunesada, Y Zhu, ZH Akutsu, T Akutsu, T Araya, A Asada, H Barton, MA Fujiki, Y Fujimoto, MK Fujita, R Fukushima, M Futamase, T Hamuro, Y Haruyama, T Hayakawa, H Heinzel, G Horikoshi, G Iguchi, H Ioka, K Ishitsuka, H Kamikubota, N Kaneyama, T Karasawa, Y Kasahara, K Kasai, T Katsuki, M Kawabe, K Kawamura, M Kawashima, N Kawazoe, F Kojima, Y Kokeyama, K Kozai, Y Kudoh, H Kuroda, K Kuwabara, T Matsuda, N Miura, K Miyakawa, O Miyama, S Mizusawa, H Musha, M Nagayama, Y Nakagawa, K Nakamura, T Nakano, H Nakao, K Nishi, Y Ogawa, Y Ohashi, M Ohishi, N Okutomi, A Oohara, K Otsuka, S Saito, Y Sakata, S Sasaki, M Sato, K Sato, N Sato, Y Seki, H Sekido, A Seto, N Shibata, M Shinkai, H Shintomi, T Soida, K Suzuki, T Takamori, A Takemoto, S Takeno, K Tanaka, T Taniguchi, K Taniguchi, S Tanji, T Taylor, CT Telada, S Tochikubo, K Tokunari, M Tomaru, T Tsubono, K Tsuda, N Uchiyama, T Ueda, A Ueda, K Usui, F Waseda, K Watanabe, Y Yakura, H Yamamoto, A Yamamoto, K Yamazaki, T Yanagi, Y Yoda, T Yokoyama, J Yoshida, T TI Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses SO PHYSICAL REVIEW D LA English DT Article ID LASER-INTERFEROMETER; SEARCH; LIGO; TELESCOPE; DYNAMICS; EVENTS; GALAXY; MODEL; SKY AB We present data-analysis schemes and results of observations with the TAMA300 gravitational wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp wave analysis, because precise waveform templates are not available. We used an excess -power filter for the extraction of gravitational wave candidates, and developed two methods for the reduction of fake events caused by nonstationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. In addition, in order to interpret the event candidates from an astronomical viewpoint, we performed a Monte-Carlo simulation with an assumed Galactic event distribution model and with burst waveforms obtained from numerical simulations of stellar-core collapses. We set an upper limit of 5.0x10(3) events/sec on the burst gravitational wave event rate in our Galaxy with a confidence level of 90%. This work shows prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector. C1 Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Natl Astron Observ, Tokyo 1818588, Japan. Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Osaka City Univ, Grad Sch Sci, Sumiyoshi Ku, Osaka 5588585, Japan. Univ Tokyo, Inst Cosm Ray Res, Chiba 2778582, Japan. Univ Tokyo, Dept Adv Mat Sci, Chiba 2778561, Japan. Natl Inst Informat & Commun Technol, Tokyo 1848795, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Osaka Univ, Grad Sch Sci, Osaka 5600043, Japan. Niigata Univ, Fac Sci, Niigata 9502102, Japan. Univ Tokyo, Earthquake Res Inst, Bunkyo Ku, Tokyo 1130032, Japan. Hirosaki Univ, Fac Sci & Technol, Hirosaki, Aomori 0368561, Japan. Tohoku Univ, Grad Sch Sci, Sendai, Miyagi 9808578, Japan. High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Max Planck Inst Gravitat Phys, D-30167 Hannover, Germany. Tokyo Inst Technol, Meguro Ku, Tokyo 1528551, Japan. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. LIGO Hanford Observ, Richland, WA 99352 USA. Kyoto Univ, Fac Sci, Sakyo Ku, Kyoto 6068502, Japan. Kinki Univ, Osaka 5778502, Japan. Ochanomizu Univ, Bunkyo Ku, Tokyo 1128610, Japan. Hiroshima Univ, Dept Phys, Hiroshima 7398526, Japan. Univ Tokyo, Dept Phys, Theoret Astrophys Grp, Bunkyo Ku, Tokyo 1130033, Japan. Tokyo Denki Univ, Chiyoda Ku, Tokyo 1018457, Japan. Miyagi Univ Educ, Dept Phys, Sendai, Miyagi 9800845, Japan. CALTECH, Pasadena, CA 91125 USA. Univ Electrocommun, Inst Laser Sci, Tokyo 1828585, Japan. Kyoto Univ, Yukawa Inst Theoret Phys, Sakyo Ku, Kyoto 6068502, Japan. Tokai Univ, Fac Engn, Div Precis Engn, Kanagawa 2591292, Japan. Waseda Univ, Shinjyuku Ku, Tokyo 1698555, Japan. Univ Tokyo, Grad Sch Arts & Sci, Meguro Ku, Tokyo 1538902, Japan. RIKEN, Wako, Saitaka 3510198, Japan. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Natl Inst Adv Ind Sci & Technol, Tsukuba, Ibaraki 3058563, Japan. ISAS, JAXA, Kanagawa 2298510, Japan. RP Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RI ANDO, MASAKI/G-4989-2014; Kawabe, Keita/G-9840-2011; Kawazoe, Fumiko/F-7700-2011; MIYAMA, Shoken/A-3598-2015; Taniguchi, Keisuke/G-2694-2011; OI ANDO, MASAKI/0000-0002-8865-9998; Nakano, Hiroyuki/0000-0001-7665-0796 NR 58 TC 16 Z9 18 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD APR PY 2005 VL 71 IS 8 AR 082002 DI 10.1103/PhysRevD.71.082002 PG 17 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 921LL UT WOS:000228765800005 ER PT J AU Carles, P Zhong, F Weilert, M Barmatz, M AF Carles, P Zhong, F Weilert, M Barmatz, M TI Temperature and density relaxation close to the liquid-gas critical point: An analytical solution for cylindrical cells SO PHYSICAL REVIEW E LA English DT Article ID VAPOR CRITICAL-POINT; PURE FLUID; COMPONENT FLUID; HEAT-CAPACITY; EQUILIBRATION; GRAVITY AB We present a study of the temperature and density equilibration near the liquid-gas critical point of a composite system consisting of a thin circular disk of near-critical fluid surrounded by a copper wall. This system is a simplified model for a proposed space experiment cell that would have 60 thin fluid layers separated by perforated copper plates to aid in equilibration. Upper and lower relaxation time limits that are based on radial and transverse diffusion through the fluid thickness are shown to be too significantly different for a reasonable estimate of the time required for the space experiment. We therefore have developed the first rigorous analytical solution of the piston effect in two dimensions for a cylindrically symmetric three-dimensional cell, including the finite conductivity of the copper wall. This solution covers the entire time evolution of the system after a boundary temperature step, from the early piston effect through the final diffusive equilibration. The calculation uses a quasistatic approximation for the copper and a Laplace-transform solution to the piston effect equation in the fluid. Laplace inversion is performed numerically. The results not only show that the equilibration is divided into three temporal regimes but also give an estimate of the amplitudes of the remaining temperature and density inhomogeneity in each regime. These results yield characteristic length scales for each of the regimes that are used to estimate the expected relaxation times in the one- and two-phase regions near the critical point. C1 Univ Paris 06, Modelisat Mecan Lab, F-75252 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Carles, P (reprint author), Univ Paris 06, Modelisat Mecan Lab, 4 Pl Jussieu, F-75252 Paris, France. NR 19 TC 5 Z9 5 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD APR PY 2005 VL 71 IS 4 AR 041201 DI 10.1103/PhysRevE.71.041201 PN 1 PG 12 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 921GO UT WOS:000228752400010 PM 15903658 ER PT J AU Kashlinsky, A AF Kashlinsky, A TI Cosmic infrared background and early galaxy evolution SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review DE cosmology; diffuse radiation-galaxies; clusters; general-galaxies; high-redshift-surveys; cosmic backgrounds ID HUBBLE DEEP FIELD; STAR-FORMATION HISTORY; SPITZER-SPACE-TELESCOPE; PROBE WMAP OBSERVATIONS; HIGH-REDSHIFT GALAXIES; POPULATION-III STARS; COBE DIRBE MAPS; AREA ISO SURVEY; SUBMILLIMETER-SELECTED GALAXIES; LYMAN-BREAK GALAXIES AB The cosmic, infrared background (CIB) reflects the sum total of galactic luminosities integrated over the entire age of he universe. From it, measurement the red-shifted starlight and dust-absorbed and re-radiated starlight of the CIB can be used to determine (or constrain) the rates of star formation and metal production as a function of time and deduce information about objects at epochs currently inaccessible to telescopic studies. This review discusses the state of current CIB measurements and the (mostly space-based) instruments with which these measurements have been made, the obstacles (the various foreground emissions) and the physics behind the CIB and its structure. Theoretical discussion of the CIB levels can now be normalized to the standard cosmological model narrowing down theoretical uncertainties. We review the information behind and theoretical modeling of both the mean (isotropic) levels of the CIB and their fluctuations. The CIB is divided into three broad bands: near-IR (NIR), mid-IR (MIR) and far-IR (FIR). For each of the bands we review the main contributors to the CIB flux and the epochs at which the bulk of the flux originates. We also discuss the data on the various quantities relevant for correct interpretation of the CIB levels: the star-formation history, the present-day luminosity function measurements, resolving the various galaxy contributors to the CIB, etc. The integrated light of all galaxies in the deepest NIR galaxy counts to date fails to match the observed mean level of the CIB, probably indicating a significant high-redshift contribution to the CIB. Additionally, Population III stars should have left a strong and measurable signature via their contribution to the CIB anisotropies for a wide range of their formation scenarios, and measuring the excess CIB anisotropies coming from high z would provide direct information on the epoch of the first stars. (c) 2005 Published by Elsevier B.V. C1 Goddard Space Flight Ctr, Astron & Solar Phys Lab, SSAI, Greenbelt, MD 20771 USA. RP Goddard Space Flight Ctr, Astron & Solar Phys Lab, SSAI, Greenbelt, MD 20771 USA. EM kashlinsky@stars.gsfc.nasa.gov NR 280 TC 94 Z9 94 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD APR PY 2005 VL 409 IS 6 BP 361 EP 438 DI 10.1016/j.physrep.2004.12.005 PG 78 WC Physics, Multidisciplinary SC Physics GA 916JK UT WOS:000228381000001 ER PT J AU Coustenis, A Ferrari, C Atreya, SK Spilker, LJ AF Coustenis, A Ferrari, C Atreya, SK Spilker, LJ TI Special issue on the "Surfaces and atmospheres of the outer planets, their satellites and ring systems" SO PLANETARY AND SPACE SCIENCE LA English DT Editorial Material C1 Observ Paris, DESPA, F-92195 Meudon, France. Univ Michigan, Ann Arbor, MI 48109 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. RP Coustenis, A (reprint author), Observ Paris, DESPA, 5,Pl Jules Jannsen,Bat 18, F-92195 Meudon, France. EM athena.coustenis@obspm.fr; ferrari@discovery.sacaly.cea.fr; atreya@umich.edu; linda.j.spilker@jpl.nasa.gov RI Ferrari, Cecile/P-9735-2016 OI Ferrari, Cecile/0000-0001-5962-7439 NR 0 TC 1 Z9 1 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 459 EP 460 DI 10.1016/j.pss.2004.12.001 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000001 ER PT J AU Atreya, SK Wong, AS Baines, KH Wong, MH Owen, TC AF Atreya, SK Wong, AS Baines, KH Wong, MH Owen, TC TI Jupiter's ammonia clouds - localized or ubiquitous? SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 28th European Geophysical Union Meeting CY APR 06-11, 2004 CL Nice, FRANCE ID PROBE MASS-SPECTROMETER; NORTH EQUATORIAL BELT; GALILEO PROBE; JOVIAN ATMOSPHERE; HAZE FORMATION; THERMAL STRUCTURE; MOIST CONVECTION; POLAR ATMOSPHERE; GIANT PLANETS; ICE AB From an analysis of the Galileo Near Infrared Imaging Spectrometer (NIMS) data, Baines et al. (Icarus 159 (2002) 74) have reported that spectrally identifiable ammonia clouds (SIACs) cover less than 1% of Jupiter. Localized ammonia clouds have been identified also in the Cassim Composite Infrared Spectrometer (CIRS) observations (Planet. Space Sci. 52 (2004a) 385). Yet, ground-based, satellite and spacecraft observations show that clouds exist everywhere on Jupiter. Thermochemical models also predict that Jupiter must be covered with clouds, with the top layer made up of ammonia ice. For a solar composition atmosphere, models predict the base of the ammonia clouds to be at 720mb, at 1000 mb if N/H were 4 x solar, and at 0.5 bar for depleted ammonia of 10(-2) X solar (Planet. Space Sci. 47 (1999) 1243). Thus, the above NIMS and CIRS findings are seemingly at odds with other observations and cloud physics models. We suggest that the clouds of ammonia ice are ubiquitous on Jupiter, but that spectral identification of all but the freshest of the ammonia clouds and high altitude ammonia haze is inhibited by a combination of (i) dusting, starting with hydrocarbon haze particles falling from Jupiter's stratosphere and combining with an even much larger source-the hydrazine haze; (ii) cloud properties, including ammonia aerosol particle size effects. In this paper, we investigate the role of photochemical haze and find that a substantial amount of haze material can deposit on the upper cloud layer of Jupiter, possibly enough to mask its spectral signature. The stratospheric haze particles result from condensation of polycyclic aromatic hydrocarbons (PAHs), whereas hydrazine ice: is formed from ammonia photochemistry. We anticipate similar conditions to prevail on Saturn. © 2005 Elsevier Ltd. All rights reserved. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Atreya, SK (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. EM atreya@umich.edu NR 59 TC 26 Z9 26 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 498 EP 507 DI 10.1016/j.pss.2004.04.002 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000005 ER PT J AU Negrao, A Roos-Serote, M Rannou, P Rages, K Lourenco, B AF Negrao, A Roos-Serote, M Rannou, P Rages, K Lourenco, B TI On the latitudinal distribution of Titan's haze at the Voyager epoch SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 28th European Geophysical Union Meeting CY APR 06-11, 2004 CL Nice, FRANCE DE Titan; atmosphere; haze; Voyager; imaging ID VERTICAL-DISTRIBUTION; ADAPTIVE OPTICS; ATMOSPHERE; AEROSOLS; IMAGES; SCATTERING; GROWTH; MODELS; HST AB We have analysed all the available high phase angle images of Titan limb taken by Voyager I and 2, in early 1980. For several different phase angles and wavelengths, we seek., for a consistent set of haze parameters able to fit all data simultaneously. Our main purpose is to obtain an accurate estimate of the latitudinal variation of haze opacity at 200 km altitude at the time of the Voyager flyby's. We find that haze opacity at 200 km is about constant in the southern hemisphere and drops between equator and 60&DEG; N by about 30-50%, sharply increasing again beyond 60&DEG; N. The latter feature is clearly due to the north polarhood. This behaviour is opposite to total optical depth variations retrieved from IRIS observation, at the same epoch. The IRIS data refer to levels below 100 km altitude. A comparison of our results with calculations from a general circulation model, shows that (1) our results are realistic and can be considered as robust (2) the opacity variations at 200 km (this work) and at ground (IRIS data), although opposite, are not inconsistent with each other. © 2005 Elsevier Ltd. All rights reserved. C1 Observ Paris, F-92195 Meudon, France. Univ Lisbon, Fac Sci, P-1699 Lisbon, Portugal. Lisbon Astron Observ, P-1349018 Lisbon, Portugal. Univ Versailles St Quentin, IPSL, Serv Aeron, Versailles, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Negrao, A (reprint author), Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France. EM alberto.negrao@obspm.fr RI RANNOU, Pascal/I-9059-2012; OI Negrao, Alberto/0000-0001-6042-1294 NR 30 TC 3 Z9 3 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 526 EP 534 DI 10.1016/j.pss.2004.08.007 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000007 ER PT J AU Seiff, A Stoker, CR Young, RE Mihalov, JD McKay, CP Lorenz, RD AF Seiff, A Stoker, CR Young, RE Mihalov, JD McKay, CP Lorenz, RD TI Determination of physical properties of a planetary surface by measuring the deceleration of a probe upon impact: Application to Titan SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 28th European Geophysical Union Meeting CY APR 06-11, 2004 CL Nice, FRANCE ID DYNAMICS AB We report scale model laboratory experiments showing how an impact accelerometer on a planetary probe (based on the Huygens probe Phase A configuration) can provide significant information on the mechanical characteristics of the surface. In particular, solid and liquid surfaces can be discriminated, The density of liquids can in principle be determined from the peak deceleration, thereby providing a constraint on composition, although experimental uncertainties present challenges to the accuracy of this method. © 2005 Elsevier Ltd. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. San Jose Univ Fdn, San Jose, CA USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Lorenz, RD (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM rlorenz@lpl.arizona.edu RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 8 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 594 EP 600 DI 10.1016/j.pss.2004.05.002 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000012 ER PT J AU Justus, CG Duvall, A Keller, VW Spilker, TR Lockwood, MK AF Justus, CG Duvall, A Keller, VW Spilker, TR Lockwood, MK TI Connecting atmospheric science and atmospheric models for aerocapture at Titan and the outer planets SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 28th European Geophysical Union Meeting CY APR 06-11, 2004 CL Nice, FRANCE DE aerocapture; global reference atmospheric model; Titan atmosphere; Titan-GRAM; Neptune atmosphere; Neptune-GRAM AB Many atmospheric measurement systems, such as the sounding instruments on Voyager, gather atmospheric information in the form of temperature versus pressure level. In these terms, there is considerable consistency among the mean atmospheric profiles of the outer planets Jupiter through Neptune, including Titan. On a given planet or on Titan, the range of variability of temperature versus pressure level due to seasonal, latitudinal, and diurnal variations is also not large. However, many engineering needs for atmospheric models relate not to temperature versus pressure level but atmospheric density versus geometric altitude. This need is especially true for design and analysis of aerocapture systems. Drag force available for aerocapture is directly proportional to atmospheric density. Available aerocapture "corridor width" (allowable range of atmospheric entry angle) also depends on height rate of change of atmospheric density, as characterized by density scale height. Characteristics of hydrostatics and the gas law equation mean that relatively small systematic differences in temperature versus pressure profiles can integrate at high altitudes to very large differences in density versus altitude profiles. Thus, a given periapsis density required to accomplish successful acrocapture can occur at substantially different altitudes (&SIM; 150-300km) on the various outer planets, and significantly different density scale heights (&SIM; 20-50 km) can occur at these periapsis attitudes. This paper will illustrate these effects and discuss implications for improvements in atmospheric measurements to yield significant impact on design of acrocapture systems for future missions to Titan and the outer planets. Relatively small-scale atmospheric perturbations, such as gravity waves, tides, and other atmospheric variations can also have significant effect on design details for aerocapture guidance and control systems. This paper will discuss benefits that would result from improved understanding of Titan and outer planetary atmospheric perturbation characteristics. Details of recent engineering-level atmospheric models for Titan and Neptune will be presented, and effects of present and future levels of atmospheric uncertainty and variability characteristics will be examined. © 2005 Elsevier Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Morgan Res Corp, EV13, Huntsville, AL 35812 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Langley Res Ctr, Vehicle Anal Branch, Hampton, VA 23681 USA. RP Duvall, A (reprint author), NASA, George C Marshall Space Flight Ctr, Morgan Res Corp, EV13, Huntsville, AL 35812 USA. EM aleta.duvall@msfc.nasa.gov NR 11 TC 5 Z9 5 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 601 EP 605 DI 10.1016/j.pss.2004.12.002 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000013 ER PT J AU Spilker, TR AF Spilker, TR TI Significant science at Titan and Neptune from aerocaptured missions SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 28th European Geophysical Union Meeting CY APR 06-11, 2004 CL Nice, FRANCE DE aerocapture; Titan; Neptune; triton; science objective AB In 2001, NASA began assembling the Aerocapture Systems Analysis Team, a team of scientists and engineers from multiple NASA centers. Their charter is to perform high-fidelity analyses of delivering scientifically compelling orbital missions that use aerocapture for orbit insertion at their destinations. After establishing scientific credibility, studies focus on aerocapture systems design and performance, including approach navigation, flight mechanics, aerothermodynamics, and thermal protection. The team's October 2001-September 2002 study examined a mission to explore the organic environment of Titan and its chemical, geological, and dynamical context. Its architecture includes a Titan polar orbiter that would complete and extend Cassini's soon-to-begin global mapping, aiding global extrapolation of findings from a mobile in situ element (rover, blimp, etc.). The in situ element would perform remote sensing and in situ investigations, for analysis and characterization of Titan's surface, shallow subsurface, atmosphere, processes occurring there, and energy sources driving it all. The study concentrated on the orbiter and orbit insertion, largely treating the in situ element as a black box with data relay requirements. October 2002-September 2003 the team studied a mission to perform Cassini/Huygens-level exploration of the Neptune system. Before aerocapture this mission would deploy and support multiple Neptune atmospheric entry probes. After aerocapture the orbiter uses Triton as a "tour engine", in much the same manner as Cassini uses Titan, to provide many Triton flybys and orbit evolution for detailed investigation of Neptune's interior, atmosphere, magnetosphere, rings, and satellites. This presentation summarizes the missions' science objectives, instrumentation, and data requirements that served as the foundations for the studies, and describes mission design requirements and constraints that affect the science investigations. © 2005 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Spilker, TR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 2 Z9 2 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2005 VL 53 IS 5 SI SI BP 606 EP 616 DI 10.1016/j.pss.2004.12.003 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 923CR UT WOS:000228887000014 ER PT J AU Williams, MK Holland, DB Melendez, O Weiser, ES Brenner, JR Nelson, GL AF Williams, MK Holland, DB Melendez, O Weiser, ES Brenner, JR Nelson, GL TI Aromatic polyimide foams: factors that lead to high fire performance SO POLYMER DEGRADATION AND STABILITY LA English DT Article; Proceedings Paper CT 9th European Meeting on Fire Retardancy and Protection of Materials CY SEP 17-19, 2003 CL Lille, FRANCE DE polyimide foams; flammability; surface area; fire performance; thermal properties AB In this research, three different, closely related, polyimide foams (namely TEEK-H, TEEK-L, and TEEK-C) were comparatively studied including thermal, mechanical, surface, flammability, and degradation properties. TEEK-H series was the name given to ODPA/3,4'-ODA (4,4-oxydiphthalic anhydride/3,4-oxydianiline), TEEK-L series for BTDA/4,4'-ODA (3,3,4,4-benzophenenonetetracarboxylic dianhydride/4,4-oxydianiline), and TEEK-CL for BTDA/4,4'-DDSO2 (3,3,4,4-benzophenenone-tetracarboxylic dianhydride/4,4-diaminodiphenyl sulfone). With varying chemistries, densities, and surface areas of these foams, one has the ability to investigate the effects of subtle changes in density, surface area, and chemical structure on fire and thermal properties. Foams have much higher surface areas than solid polymers and are a greater challenge to fire retard [Weiser ES, Johnson TF, St. Clair TL, Echigo Y, Kaneshiro H, Grimsley B, Journal of High Performance Polymers 12 (2000) 1-12; Weiser ES, Baillif FF, Grimsley BW, Marchello JM, High temperature structural foam, Proceedings of the 43rd International SAMPE Symposium, May 1998, p. 730-44; Williams.MK, et al., In:, Nelson GL and Wilkie CA (Eds.), Fire and polymers: materials and solutions for hazard prevention, ACS Symposium Series 797, American Chemical Society/Oxford Press, Washington, D.C., 2001, p. 49-62; Williams MK, Nelson GL, Brenner JR, Weiser ES, St.Clair TL, Cell surface area and foam flammability, Proceedings of recent advances in flame retardancy of polymeric materials, 2001]. Detailed fire and thermal properties are discussed. Published by Elsevier Ltd. C1 NASA, Testbed Technol, Kennedy Space Ctr, FL 32899 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Florida Inst Technol, Melbourne, FL 32901 USA. RP Williams, MK (reprint author), NASA, Testbed Technol, YA-C2-T, Kennedy Space Ctr, FL 32899 USA. EM martha.k.williams@nasa.gov; nelson@fit.edu NR 11 TC 39 Z9 47 U1 6 U2 25 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-3910 J9 POLYM DEGRAD STABIL JI Polym. Degrad. Stabil. PD APR PY 2005 VL 88 IS 1 SI SI BP 20 EP 27 DI 10.1016/j.polymdegradstab.2003.12.012 PG 8 WC Polymer Science SC Polymer Science GA 905LW UT WOS:000227570800004 ER PT J AU Cuttino, JF van Dijck, BHCA Brown, AM AF Cuttino, JF van Dijck, BHCA Brown, AM TI Design and development of a toroidal flexure for extended motion applications SO PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY LA English DT Article DE toroidal flexure; extended motion; stress AB Flexure systems are used often in precision motion applications, but are significantly limited in range of motion to prevent high stress build-up and fatigue. A toroidal flexure geometry is presented that relies primarily on shear rather than tensile stiffnesses to provide greater range of motion in the axial direction at the expense of radial stiffness. The flexure design also provides for increased stiffness in the axial direction and is well suited for applications where pressure is applied to one side. Empirical relationships are presented for maximum Tresca stress and compliance as functions of the design parameters. Crown Copyright (c) 2004 Published by Elsevier Inc. All rights reserved. C1 Univ N Carolina, Charlotte, NC 28223 USA. BAM Rail BV, Dept Technol, Breda, Netherlands. NASA, Marshall Space Flight Ctr, Struct Dynam & Loads Grp, Huntsville, AL 35812 USA. RP Cuttino, JF (reprint author), Univ N Carolina, Charlotte, NC 28223 USA. EM jcuttino@uncc.edu; b.dijck@bamrail.nl NR 17 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Int. Soc. Precis. Eng. Nanotechnol. PD APR PY 2005 VL 29 IS 2 BP 135 EP 145 DI 10.1016/j.precisoneng.2003.08.005 PG 11 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA 915DE UT WOS:000228277100001 ER PT J AU Tokunaga, AT Vacca, WD AF Tokunaga, AT Vacca, WD TI The Mauna Kea Observatories near-infrared filter set. III. Isophotal wavelengths and absolute calibration SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID SPECTRAL IRRADIANCE CALIBRATION; STANDARD STARS; PHOTOMETRY; VEGA; FLUX; SYSTEM; SPECTROPHOTOMETRY; FURNACE; 5-MU-M AB The isophotal wavelengths, flux densities, and AB magnitudes for Vega (alpha Lyr) are presented for the Mauna Kea Observatories near-infrared filter set. We show that the near-infrared absolute calibrations for Vega as determined by Cohen et al. and Megessier are consistent within the uncertainties, so that either absolute calibration can be used. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Stratospher Observ Infrared Astron, Univ Space Res Assoc, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Tokunaga, AT (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM tokunaga@ifa.hawaii.edu; wvacca@mail.arc.nasa.gov NR 32 TC 113 Z9 113 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 2005 VL 117 IS 830 BP 421 EP 426 DI 10.1086/429382 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 917GS UT WOS:000228445300005 ER PT J AU Raymond, DJ Zeng, XP AF Raymond, DJ Zeng, XP TI Modelling tropical atmospheric convection in the context of the weak temperature gradient approximation SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE numerical modelling; tropical dynamics ID SEA-SURFACE TEMPERATURE; CLOUD SYSTEMS; PHASE-III; ENSEMBLE MODEL; SINGLE-COLUMN; EQUILIBRIUM; PACIFIC; GATE; ORGANIZATION; SENSITIVITY AB A cumulus ensemble model is used to simulate the interaction between tropical atmospheric convection and the large-scale tropical environment in the context of Sobel and Bretherton's (2000) weak temperature gradient approximation. In this approximation, gravity waves are assumed to redistribute buoyancy anomalies over a broad area of the tropics, thus maintaining the local virtual-ternperature profile close to the large-scale mean. This result is implemented in the model by imposing the advective effects of a hypothetical mean vertical velocity which is just sufficient to counteract the local heating induced by convection and radiation. The implied vertical advection in the moisture equation and entrainment of air from the surrounding environment have major effects on the evolution of convection in the model. The precipitation produced by the model mimics the results of a very simple model of tropical precipitation introduced by Raymond (2000), in that the mean rainfall rate predicted by the cumulus ensemble model is, to a good approximation, a function only of the mean column precipitable water. The evolution of the precipitable water, and hence the precipitation rate, is a result of the imbalance between the surface flux of moist entropy into the domain and the radiative loss of entropy out of the top of the domain. This evolution leads to a statistically steady solution in which the resulting precipitation rate is a unique function of the entropy flux imbalance. These results support the hypothesis that tropical precipitation averaged over distance scales of a few hundred kilometres and time scales of a day is a consequence only of local thermodynamic factors. C1 New Mexico Inst Min & Technol, Dept Phys, Socorro, NM 87801 USA. New Mexico Inst Min & Technol, Geophys Res Ctr, Socorro, NM 87801 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Raymond, DJ (reprint author), New Mexico Inst Min & Technol, Dept Phys, Socorro, NM 87801 USA. EM raymond@kestrel.nmt.edu NR 24 TC 75 Z9 75 U1 1 U2 6 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD APR PY 2005 VL 131 IS 608 BP 1301 EP 1320 DI 10.1256/qj.03.97 PN B PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 942DG UT WOS:000230262500001 ER PT J AU Joiner, J Poli, P AF Joiner, J Poli, P TI Note on the effect of horizontal gradients for nadir-viewing rnicrowave and infrared sounders SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE AIRS; AMSU; assimilation; azimuth angle; radiances; satellite ID OCCULTATION OBSERVATION OPERATORS; RADIATIVE-TRANSFER MODEL; ANALYSIS SYSTEM; PRODUCTS; CHANNELS AB Passive microwave and infrared nadir sounders Such as the Advanced Microwave Sounding Unit-A (AMSU-A) and the Atmospheric InfraRed Sounder (AIRS), both flying on NASA's EOS polar-orbiting Aqua satellite, provide information about vertical temperature and humidity structure that is used in data assimilation systems for numerical weather prediction and climate applications. These instruments scan across track so that, at the satellite swath edges. the satellite zenith angles can reach similar to 60 degrees. The emission path through the atmosphere as observed by the satellite is therefore slanted with respect to the satellite footprint's zenith. Although radiative transfer codes currently in use at operational centres use the appropriate satellite zenith angle to compute brightness temperature, the input atmospheric fields are those from the vertical profile above the centre of the satellite footprint. If horizontal gradients are present in the atmospheric fields, the use of a vertical atmospheric profile may produce an error. This note attempts to quantity the effects of horizontal gradients on AIRS and AMSU-A channels by computing brightness temperatures with accurate slanted atmospheric profiles. We use slanted temperature, water vapour, and ozone fields from data assimilation systems. We compare the calculated slanted and vertical brightness temperatures with AIRS and AMSU-A observations. We show that the effects of horizontal gradients on these Sounders are generally small and below instrument noise. However, there are cases where the effects are greater than the instruntent noise and may produce erroneous increments in an assimilation system. The majority of the affected channels have weighting functions that peak in the upper troposphere (water-vapour-sensitive channels) and above (temperature-sensitive channels) and are unlikely to significantly impact on tropospheric numerical weather prediction. However, the errors could be significant for other applications Such as stratospheric analysis. Gradients in ozone and tropospheric temperature appear to be well captured by the analyses. In contrast, gradients in upper stratospheric and mesospheric temperature as well as upper-tropospheric humidity are less well captured. This is likely due in part to a lack of data to specify these fields accurately in the analyses. Advanced sounders, like AIRS, will help to better specify these fields in the future. C1 NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Joiner, J (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 916, Greenbelt, MD 20771 USA. EM joanna.joiner@nasa.gov RI Joiner, Joanna/D-6264-2012; OI Poli, Paul/0000-0002-8392-6524 NR 13 TC 3 Z9 3 U1 0 U2 0 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD APR PY 2005 VL 131 IS 608 BP 1783 EP 1792 DI 10.1256/qj.041.125 PN B PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 942DG UT WOS:000230262500023 ER PT J AU Snell, EH Helliwell, JR AF Snell, EH Helliwell, JR TI Macromolecular crystallization in microgravity SO REPORTS ON PROGRESS IN PHYSICS LA English DT Review ID PROTEIN CRYSTAL-GROWTH; X-RAY-DIFFRACTION; INTERNATIONAL-SPACE-STATION; TETRAGONAL LYSOZYME CRYSTALS; BRAGG REFLECTION PROFILES; LIQUID-LIQUID DIFFUSION; CCD VIDEO OBSERVATION; ANGSTROM RESOLUTION; VAPOR-DIFFUSION; BIOLOGICAL MACROMOLECULES AB Density difference fluid flows and sedimentation of growing crystals are greatly reduced when crystallization takes place in a reduced gravity environment. In the case of macromolecular crystallography a crystal of a biological macromolecule is used for diffraction experiments (x-ray or neutron) so as to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal then the greater the molecular structure detail that can be extracted. It is this structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences, with major potential in understanding disease pathologies. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyse the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural advances. Finally, limitations and alternatives to microgravity and future directions for this research are covered. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry and mathematics meet to enable insight to the fundamentals of life. As the reader will see, there is a great deal of physics involved when the microgravity environment is applied to crystallization, some of it known, and undoubtedly much yet to discover. C1 NASA, George C Marshall Space Flight Ctr, Biophys Grp, Huntsville, AL 35812 USA. Univ Manchester, Dept Chem, Manchester M13 9PL, Lancs, England. CCLRC Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RP Snell, EH (reprint author), NASA, George C Marshall Space Flight Ctr, Biophys Grp, Code XD42, Huntsville, AL 35812 USA. EM eddie.snell@msfc.nasa.gov; john.helliwell@manchester.ac.uk RI Helliwell, John /C-4587-2014 OI Helliwell, John /0000-0002-0520-7540 NR 218 TC 59 Z9 65 U1 6 U2 19 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0034-4885 J9 REP PROG PHYS JI Rep. Prog. Phys. PD APR PY 2005 VL 68 IS 4 BP 799 EP 853 DI 10.1088/0034-4885/68/4/R02 PG 55 WC Physics, Multidisciplinary SC Physics GA 924FI UT WOS:000228964000002 ER PT J AU Chuang, WH Luger, T Ghodssi, R Fettig, RK AF Chuang, WH Luger, T Ghodssi, R Fettig, RK TI A cryogenic measurement setup for microelectromechanical systems used in space applications SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MECHANICAL-PROPERTIES; MICROSHUTTER ARRAYS; THIN-FILMS; SILICON AB We present a cryogenic measurement setup installed inside a focused-ion-beam (FIB) system to characterize and microrepair microelectromechanical systems (MEMS) for space applications. The setup allows testing of MEMS devices under vacuum condition of 10(-6) Torr at variable temperatures ranging from 298 to 20 K. In the experiment, a lead-zirconate-titanate translator powered by a function generator and a dc voltage is utilized as an actuator, and a thin-film thermo-resistor fabricated with test devices is used as an integrated temperature sensor. Additionally, a motorized x-y-z stage is installed to achieve highly accurate positioning function. Resonant techniques and bending tests based on the designed setup are developed to measure the mechanical properties of silicon nitride thin films at cryogenic temperatures. Combined with the functions of the FIB system, this setup also demonstrates the capability to microrepair microshutter arrays, programmable field selectors in the NASA James Webb Space Telescopes. The presented test setup exhibits its feasibility to test MEMS devices needed for the space applications and can be extended to other cryogenic applications. (C) American Institute of Physics. C1 Univ Maryland, Dept Elect & Comp Engn, MEMS Sensors & Actuators Lab, College Pk, MD 20742 USA. Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ghodssi, R (reprint author), Univ Maryland, Dept Elect & Comp Engn, MEMS Sensors & Actuators Lab, V Williams Bldg,Room 1357, College Pk, MD 20742 USA. EM ghodssi@eng.umd.edu NR 17 TC 0 Z9 1 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 2005 VL 76 IS 4 AR 045105 DI 10.1063/1.1884192 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 916CE UT WOS:000228362200041 ER PT J AU du Toit, CF AF du Toit, CF TI Finders keepers SO SCIENTIFIC AMERICAN LA English DT Letter C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP du Toit, CF (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD APR PY 2005 VL 292 IS 4 BP 16 EP 16 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 907JM UT WOS:000227712900006 ER PT J AU Gargano, P Mosca, H Bozzolo, G AF Gargano, P Mosca, H Bozzolo, G TI Atomistic modeling of Ru-Al-Ta alloys SO SCRIPTA MATERIALIA LA English DT Article DE intermetallic compounds; ruthenium alummides; computational modeling; Heusler alloys ID PHASE; ADDITIONS; SYSTEMS; CU; TI AB Atomistic modeline of Ru-Al-Ta alloys was used to determine the energetics of ordered structures in this ternary system, providing insight to the formation of the recently discovered L2(1)Ru(2)AlTa Heusler phase, as well as other ordered structures in the Ru-Al-Ta system. (C) 2004 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. C1 NASA, Glenn Res Ctr Lewis Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Comis Nacl Energia Atom, UA Mat, Ctr Atom Constituyentes, RA-1429 Buenos Aires, DF, Argentina. RP Bozzolo, G (reprint author), NASA, Glenn Res Ctr Lewis Ctr, Mail Stop 23-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM guillermo.h.bozzolo@grc.nasa.gov NR 19 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD APR PY 2005 VL 52 IS 7 BP 663 EP 668 DI 10.1016/j.scriptamat.2004.11.028 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 895PA UT WOS:000226874200022 ER PT J AU White, SM Thomas, RJ Schwartz, RA AF White, SM Thomas, RJ Schwartz, RA TI Updated expressions for determining temperatures and emission measures from goes soft X-ray measurements SO SOLAR PHYSICS LA English DT Article ID ATOMIC DATABASE; LABORATORY MEASUREMENTS; ELEMENTAL ABUNDANCES; CORONAL ABUNDANCES; LINE EMISSION; SOLAR CORONA; CHIANTI; SPECTRUM; FE; XXIV AB {We investigate the conversion of the 0.5-4 and 1-8 angstrom soft X-ray flux measurements made by detectors on the Geostationary Operational Environmental Satellites (GOES) into temperature and emission measures of coronal plasma using modern spectral models and modern understanding of coronal abundances. In particular, the original analysis by Thomas, Starr and Crannell (1985) is updated to take into account the realization that coronal abundances may be quite different from photospheric abundances. An important result of this analysis is that the derived temperatures and emission measures depend strongly on the assumed abundances even at high temperatures where continuum rather than spectral lines dominates the Sun's X-ray spectrum. This occurs because the higher coronal abundances mean that most of the continuum is due to free-bound emission processes, not free-free emission, and thus is abundance-dependent. We find significant differences between modern calculations of the temperature response of the flux measurements and the versions currently in use: for a typical flare, emission measures may be up to a factor of 4 smaller than the current software suggests. Derived temperatures are similar for both photospheric and coronal abundances for cool flares (e.g., 15 MK), but for hot flares (e.g., 35 MK) coronal abundances can lead to significantly (similar to 25%) lower temperatures being derived. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP White, SM (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM white@astro.umd.edu NR 30 TC 85 Z9 85 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD APR PY 2005 VL 227 IS 2 BP 231 EP 248 DI 10.1007/s11207-005-2445-z PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 942YX UT WOS:000230319900004 ER PT J AU Wu, CC Fry, CD Berdichevsky, D Dryer, M Smith, Z Detman, T AF Wu, CC Fry, CD Berdichevsky, D Dryer, M Smith, Z Detman, T TI Predicting the arrival time of shock passages at Earth SO SOLAR PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; 3-DIMENSIONAL MHD SIMULATION; CORONAL MASS EJECTION; 1 AU; SOLAR-WIND; REAL-TIME; PROPAGATION; MODELS AB The purpose of this parametric study is to predict the arrival time at Earth of shocks due to disturbances observed on the Sun. A 3D magnetohydrodynamic (MHD) simulation code is used to simulate the evolution of these disturbances as they propagate out to 1 AU. The model in Han, Wu and Dryer (1988) uses solar data for input at 0.08 AU (18 solar radii). The initial shock speed (ISS) is assumed to be constant from the corona to 0.08 AU. We investigate how variations of this ISS affect the arrival times of the shock at Earth. This basic parametric study, however, does not consider inhomogeneous background solar wind structures such as corotating interaction regions and their precursor stream-stream interactions, nor interplanetary manifestations of complex coronal mass ejecta such as magnetic clouds. In the latter case, only their associated shocks are considered. Because the ambient (pre-existing background) solar wind speed is known to affect the shock arrival time at 1 AU, we also simulated events with various background solar wind speeds (BSWS) to investigate this effect. The results show that the shock arrival time at Earth depends on the BSWS, the speed of solar disturbances, their size, and their source location at the Sun. However, it is found that for a sufficiently large momentum input, the shock arrival time at Earth is not significantly affected by the pre-existing solar wind speed. C1 Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Explorat Phys Int Inc, Huntsville, AL 35806 USA. L3 Commun EER Syst Inc, Largo, MD 20774 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. RP Wu, CC (reprint author), Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. EM wuc@cspar.uah.edu RI xue, yansheng/A-9712-2012 NR 31 TC 19 Z9 19 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD APR PY 2005 VL 227 IS 2 BP 371 EP 386 DI 10.1007/s11207-005-1213-4 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 942YX UT WOS:000230319900013 ER PT J AU Kimura, Y Kaito, C AF Kimura, Y Kaito, C TI Formation of new carbides with diamond structure from carbon film containing transition metal. SO THIN SOLID FILMS LA English DT Article DE annealing; carbides; heat treatment; transmission electron microscopy (TEM) ID NANOTUBES; GROWTH AB New carbide crystallites, which have a solid-solution phase with diamond structure, were formed from amorphous carbon film containing a transition metal such as Fe, Co, Mo or Ti by vacuum heating at 500-800 degrees C. The lattice constants for each solid-solution phase have been determined from electron diffraction patterns and high-resolution transmission electron microscope images. The formation of carbon polymorphs has been summarized as being dependent on the heat treatment temperature. (c) 2004 Elsevier B.V. All rights reserved. C1 Ritsumeikan Univ, Dept Phys, Shiga 5258577, Japan. RP Kimura, Y (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 691, Greenbelt, MD 20771 USA. EM rp092955@se.ritsumei.ac.jp RI Kimura, Yuki/J-9635-2014 OI Kimura, Yuki/0000-0002-9218-7663 NR 9 TC 3 Z9 3 U1 1 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 1 PY 2005 VL 476 IS 1 BP 65 EP 67 DI 10.1016/j.tsf.2004.09.015 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 904PB UT WOS:000227509100008 ER PT J AU Watson, SM Zeng, L Musielski, J Wincheski, RA Wilkerson, AL Broitman, E Holloway, C Reilly, AC AF Watson, SM Zeng, L Musielski, J Wincheski, RA Wilkerson, AL Broitman, E Holloway, C Reilly, AC TI Carbon nitride as a buffer layer for magnetic thin films SO THIN SOLID FILMS LA English DT Article DE carbon (58); nitrides; magnetic properties (282); surface morphology (462) ID GRANULAR FILMS; NANOLAMINATION AB Amorphous carbon nitride (CNx, (0.1 < x < 0.3)) thin films present a unique combination of hardness and compliance and may be useful for incorporation into ferromagnetic multilayers. We present a study of the use of amorphous CNx as a buffer layer for NiFe magnetic thin films. The surface roughness of the NiFe films is comparable to films on Ta or Cu buffer layers and is stable with annealing at 200 degrees C. Effects on the magnetization and coercivity are seen, and may be due to several mechanisms, including chemical reactions at the interface and interdiffusion. (c) 2004 Elsevier B.V. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Reilly, AC (reprint author), Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. EM rcilly@physics.wm.edu RI Zeng, Li/B-5932-2008; Broitman, Esteban/L-6950-2015 OI Broitman, Esteban/0000-0003-3277-1945 NR 13 TC 0 Z9 0 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 1 PY 2005 VL 476 IS 1 BP 148 EP 151 DI 10.1016/j.tsf.2004.09.036 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 904PB UT WOS:000227509100021 ER PT J AU DellaCorte, C AF DellaCorte, C TI Words that aren't what they appear center dot center dot center dot SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD APR PY 2005 VL 61 IS 4 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 913JT UT WOS:000228148500002 ER PT J AU Del Genio, AD Wolf, AB Yao, MS AF Del Genio, AD Wolf, AB Yao, MS TI Evaluation of regional cloud feedbacks using single-column models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CIRRUS CLOUDS; PART I; PARAMETERIZATION; TEMPERATURE; COMBINATION; SURFACE; RADAR; ECMWF; ISCCP AB [1] Cloud feedbacks in a warmer climate have not yet been constrained by models or observations. We present an approach that combines a general circulation model (GCM), single-column model (SCM), satellite and surface remote sensing data, and analysis product to infer regional cloud feedbacks and evaluate model simulations of them. The Atmospheric Radiation Measurement ( ARM) Program Southern Great Plains (SGP) continuous forcing product, derived from a mesoscale analysis constrained by top-of-atmosphere and surface data, provides long-term advective forcing that links the models to the data. We drive an SCM with the continuous forcing for 10 cold season months in which synoptic forcing dominates the meteorology. Cloud feedbacks in midlatitude winter are primarily responses to changes in dynamical forcing. Thus we select times when observed advective forcing anomalies resemble doubled CO2 advective forcing changes in the parent GCM. For these times we construct cloud type anomaly histograms in the International Satellite Cloud Climatology Project and Active Remotely Sensed Cloud Locations data sets and simulated versions of these histograms in the SCM. Comparison of the SCM subset to GCM doubled CO2 cloud type changes tells us how relevant the selected times are to the GCM's cloud feedbacks, while comparisons of the SCM to the data tell us how well the model performs in these situations. The data suggest that in midlatitude winter, high thick clouds should increase while cirrus and low clouds decrease in upwelling regimes in a climate warming. Downwelling regime cloud feedbacks are dominated by changes in low clouds but are not as well constrained by the data. C1 NASA, SGT Inc, Goddard Inst Space Studies, New York, NY 10025 USA. RP Del Genio, AD (reprint author), NASA, SGT Inc, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM adelgenio@giss.nasa.gov RI Del Genio, Anthony/D-4663-2012 OI Del Genio, Anthony/0000-0001-7450-1359 NR 17 TC 17 Z9 17 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 31 PY 2005 VL 110 IS D15 AR D15S13 DI 10.1029/2004JD005011 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 916ED UT WOS:000228367300001 ER PT J AU Li, ZH Muller, JP Cross, P Fielding, EJ AF Li, ZH Muller, JP Cross, P Fielding, EJ TI Interferometric synthetic aperture radar (InSAR) atmospheric correction: GPS, moderate resolution Imaging spectroradiometer (MODIS), and InSAR integration SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SURFACE DEFORMATION; LOS-ANGELES; GROUNDWATER AB [1] Atmospheric effects represent one of the major limitations of repeat-pass interferometric synthetic aperture radar (InSAR). In this paper, GPS, and Moderate Resolution Imaging Spectroradiometer (MODIS) data were integrated to provide regional water vapor fields with a spatial resolution of 1 km x 1 km, and a water vapor correction model based on the resultant water vapor fields was successfully incorporated into the Jet Propulsion Laboratory/California Institute of Technology ROI_PAC software. The advantage of this integration approach is that only one continuous GPS station is required within a 2030 km x 1354 km MODIS scene. Application to ERS-2 repeat-pass data over the Los Angeles Southern California Integrated GPS Network (SCIGN) area shows that this integration approach not only helps discriminate geophysical signals from atmospheric artifacts but also reduces water vapor effects significantly, which is of great interest to a wide community of geophysicists. C1 UCL, Dept Geomat Engn, London, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Cambridge, Dept Earth Sci, Cambridge CB2 3EQ, England. Univ Cambridge, Bullard Labs, Cambridge, England. RP UCL, Dept Geomat Engn, London, England. EM zhli@ge.ucl.ac.uk RI NCEO, COMET+`/A-3443-2013; Li, Zhenhong/F-8705-2010; Fielding, Eric/A-1288-2007 OI Li, Zhenhong/0000-0002-8054-7449; Fielding, Eric/0000-0002-6648-8067 NR 25 TC 76 Z9 83 U1 3 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 31 PY 2005 VL 110 IS B3 AR B03410 DI 10.1029/2004JB003446 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 916EZ UT WOS:000228369500001 ER PT J AU Burian, SJ Shepherd, JM AF Burian, SJ Shepherd, JM TI Effect of urbanization on the diurnal rainfall pattern in Houston SO HYDROLOGICAL PROCESSES LA English DT Article DE inadvertent weather modification; urbanization; diurnal rainfall distribution ID MAJOR URBAN AREAS; ST-LOUIS; THUNDERSTORMS; FREQUENCY; IMPACTS AB Data from 19 raingauges located within and nearby Houston were analysed to quantify the impact of urbanization of the Houston metropolitan area on the local diurnal rainfall pattern. The average annual and warm-season diurnal rainfall patterns were determined for one time period when Houston was relatively small and likely would not have had a significant effect on meteorological processes (1940-58) and for a second, more recent, time period after Houston had become a major metropolitan area (1984-99). The diurnal rainfall patterns within the hypothesized urban-affected region and an upwind control region were compared for the pre- and post-urban time periods. Results indicated that the diurnal rainfall distribution in the urban area is much different than that found for the upwind and downwind adjacent regions for the 1984 to 1999 time period. For an average warm season from 1984 to 1999, the urban area and downwind urban-impacted region registered 59% and 30% respectively greater rainfall amounts from noon to midnight than an upwind control region. Moreover, the urban area had approximately 80% more recorded rainfall occurrences between noon and midnight during the warm season than surrounding areas. Comparison of the pre- and post-urban rainfall patterns indicated that the diurnal rainfall distribution has changed in southeast Texas. The changes are most significant in the urban area, especially for the afternoon time increments during the warm season. The average warm-season rainfall amount registered in the urban area increased by 25% from the pre- to the post-urban time period, while the amount in the upwind control region decreased by 8%. The majority of the increase was observed for the noon to 4 p.m. and 4 p.m. to 8 p.m. time increments. Copyright (c) 2005 John Wiley D Sons, Ltd. C1 Univ Utah, Dept Civil & Environm Engn, Salt Lake City, UT 84112 USA. NASA, Goddard Space Flight Ctr, Earth Sci Enterprise, Greenbelt, MD 20771 USA. RP Burian, SJ (reprint author), Univ Utah, Dept Civil & Environm Engn, 122 S Cent Campus Dr,Suite 104, Salt Lake City, UT 84112 USA. EM burian@eng.utah.edu OI Burian, Steven/0000-0003-0523-4968 NR 26 TC 59 Z9 63 U1 2 U2 25 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0885-6087 J9 HYDROL PROCESS JI Hydrol. Process. PD MAR 30 PY 2005 VL 19 IS 5 BP 1089 EP 1103 DI 10.1002/hyp.5647 PG 15 WC Water Resources SC Water Resources GA 909LR UT WOS:000227861900007 ER PT J AU Zhao, MS Heinsch, FA Nemani, RR Running, SW AF Zhao, MS Heinsch, FA Nemani, RR Running, SW TI Improvements of the MODIS terrestrial gross and net primary production global data set SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MODIS; remote sensing; global primary production; improvements ID ATMOSPHERIC CO2; MIDLATITUDE FOREST; CARBON-DIOXIDE; UNITED-STATES; LEAF-AREA; ECOSYSTEMS; SATELLITE; CLIMATE; INDEX; NDVI AB MODIS primary production products (MOD 17) are the first regular, near-real-time data sets for repeated monitoring of vegetation primary production on vegetated land at 1-km resolution at an 8-day interval. But both the inconsistent spatial resolution between the gridded meteorological data and MODIS pixels, and the cloud-contaminated MODIS FPAR/LAI (MOD15A2) retrievals can introduce considerable errors to Collection4 primary production (denoted as C4 MOD 17) results. Here, we aim to rectify these problems through reprocessing key inputs to MODIS primary vegetation productivity algorithm, resulting in improved Collection5 MOD17 (here denoted as C5 MOD17) estimates. This was accomplished by spatial interpolation of the coarse resolution meteorological data input and with temporal filling of cloud-contaminated MOD15A2 data. Furthermore, we modified the Biome Parameter Look-Up Table (BPLUT) based on recent synthesized NPP data and some observed GPP derived from some flux tower measurements to keep up with the improvements in upstream inputs. Because MOD17 is one of the down-stream MODIS land products, the performance of the algorithm can be largely influenced by the uncertainties from upstream inputs, such as land cover, FPAR/LAI, the meteorological data, and algorithm itself. MODIS GPP fits well with GPP derived from 12 flux towers over North America. Globally, the 3-year MOD17 NPP is comparable to the Ecosystem Model-Data Intercomparison (EMDI) NPP data set, and global total MODIS GPP and NPP are inversely related to the observed atmospheric CO2 growth rates, and MEI index, indicating MOD 17 are reliable products. From 2001 to 2003, mean global total GPP and NPP estimated by MODIS are 109.29 Pg C/year and 56.02 Pg C/year, respectively. Based on this research, the improved global MODIS primary production data set is now ready for monitoring ecological conditions, natural resources and environmental changes. (c) 2005 Elsevier Inc. All rights reserved. C1 Univ Montana, Numer Terradynam Simulat Grp, Dept Ecosyst & Conservat Sci, Missoula, MT 59812 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zhao, MS (reprint author), Univ Montana, Numer Terradynam Simulat Grp, Dept Ecosyst & Conservat Sci, Missoula, MT 59812 USA. EM zhao@ntsg.umt.edu RI Zhao, Maosheng/G-5706-2010 NR 60 TC 528 Z9 579 U1 28 U2 188 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 30 PY 2005 VL 95 IS 2 BP 164 EP 176 DI 10.1016/j.rse.2004.12.011 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 911ID UT WOS:000227994900003 ER PT J AU Delozier, DM Tigelaar, DM Watson, KA Smith, JG Klein, DJ Lillehei, PT Connell, JW AF Delozier, DM Tigelaar, DM Watson, KA Smith, JG Klein, DJ Lillehei, PT Connell, JW TI Investigation of ionomers as dispersants for single wall carbon nanotubes SO POLYMER LA English DT Article DE polyimides; poly(pyrylium salts); modified nanotubes ID AROMATIC POLY(PYRIDINIUM SALT)S; ORGANIC POLYMER; FUNCTIONALIZATION; COMPOSITE; SOLUBILIZATION; SONICATION; POLYIMIDE; CHEMISTRY; NAFION AB A novel conjugated ionomer was prepared from a diamine and a bis(pyrylium salt). Single-walled carbon nanotubes (SWNT) were dispersed in solutions of the ionomer in N,N-dimethylacetamide resulting in homogenous suspensions or quasi-solutions. These suspensions were used to cast unoriented thin films. In addition, the ionomer/SWNT solutions were used to aid in the dispersal of SWNTs in a soluble, low color polyimide. The use of the ionomer as a dispersant enabled the nanotubes to be dispersed at loading levels up to 1 wt% in a polyimide solution without visual agglomeration. SWNTs were well dispersed in the thin films as evidenced by visual inspection, optical microscopy, and high resolution scanning electron microscopy. The films were further characterized for their electrical and mechanical properties. (c) 2005 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. EM d.m.delozier@larc.nasa.gov RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 44 TC 22 Z9 24 U1 0 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD MAR 29 PY 2005 VL 46 IS 8 BP 2506 EP 2521 DI 10.1016/j.polymer.2005.01.051 PG 16 WC Polymer Science SC Polymer Science GA 910FL UT WOS:000227915800010 ER PT J AU Liu, HQ Pinker, RT Holben, BN AF Liu, HQ Pinker, RT Holben, BN TI A global view of aerosols from merged transport models, satellite, and ground observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEA-SURFACE TEMPERATURE; RESOLUTION IMAGING SPECTRORADIOMETER; EMPIRICAL ORTHOGONAL FUNCTIONS; OPTICAL DEPTH; TROPOSPHERIC AEROSOLS; ANTHROPOGENIC AEROSOLS; MODIS RETRIEVALS; SULFATE AEROSOLS; GOCART MODEL; AVHRR DATA AB [1] Growing recognition of the importance of natural and anthropogenic aerosols in climate research led to numerous efforts to obtain information on aerosols based on model simulations, satellite remote sensing, and ground observations. This study describes an approach to combine information from independent sources that complement each other in their capabilities to achieve a global characterization of monthly mean clear-sky daytime aerosol optical depth. The following sources of information have been used: simulations from the Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model; retrievals from the Moderate Resolution Imaging Spectroradiometer ( MODIS) instrument on the Terra satellite; and measurements from the Aerosol Robotic Network (AERONET). Leading empirical orthogonal functions (EOFs) are used to represent the significant variation signals from model and satellite results; the EOFs are fitted to the ground observations to propagate the AERONET information at a global scale. The methodology is implemented with a 2-year time record when collocated data from all three sources are available. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. EM pinker@atmos.umd.edu RI Pinker, Rachel/F-6565-2010; Liu, Hongqing/F-5608-2010 OI Liu, Hongqing/0000-0002-9246-5379 NR 66 TC 27 Z9 27 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 26 PY 2005 VL 110 IS D10 AR D10S15 DI 10.1029/2004JD004695 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 913LY UT WOS:000228154400002 ER PT J AU Tanre, D Kaufman, Y Nakajima, T Ramanathan, V AF Tanre, D Kaufman, Y Nakajima, T Ramanathan, V TI Preface to special section on global aerosol system SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLIMATE C1 Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. Univ Calif San Diego, Scripps Inst Oceanog, Ctr Clouds Chem & Climate, La Jolla, CA 92093 USA. RP Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. RI Nakajima, Teruyuki/H-2370-2013 OI Nakajima, Teruyuki/0000-0002-9042-504X NR 24 TC 3 Z9 3 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 26 PY 2005 VL 110 IS D10 AR D10S01 DI 10.1029/2004JD005724 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 913LY UT WOS:000228154400004 ER PT J AU Birn, J Galsgaard, K Hesse, M Hoshino, M Huba, J Lapenta, G Pritchett, PL Schindler, K Yin, L Buchner, J Neukirch, T Priest, ER AF Birn, J Galsgaard, K Hesse, M Hoshino, M Huba, J Lapenta, G Pritchett, PL Schindler, K Yin, L Buchner, J Neukirch, T Priest, ER TI Forced magnetic reconnection SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID THIN CURRENT SHEETS; MHD SIMULATIONS; MAGNETOTAIL; CONFIGURATIONS; CHALLENGE; DYNAMICS; HYBRID; FIELD AB Using a multi-code approach, we investigate current sheet thinning and the onset and progress of fast magnetic reconnection, initiated by temporally limited, spatially varying, inflow of magnetic flux. The present study extends an earlier collaborative effort into the transition regime from thick to thin current sheets. Again we find that full particle, hybrid, and Hall-MHD simulations lead to the same fast reconnection rates, apparently independent of the dissipation mechanism. The reconnection rate in MHD simulations is considerably larger than in the earlier study, although still somewhat smaller than in the particle simulations. All simulations lead to surprisingly similar final states, despite differences in energy transfer and dissipation. These states are contrasted with equilibrium models derived for the same boundary perturbations. The similarity of the final states indicates that entropy conservation is satisfied similarly in fluid and kinetic approaches and that Joule dissipation plays only a minor role in the energy transfer. C1 Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. Niels Bohr Inst Astron Phys & Geophys, DK-2100 Copenhagen, Denmark. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Dept Earth & Planetary Phys, Bunkyo Ku, Tokyo 1130033, Japan. USN, Res Lab, Washington, DC 20375 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Ruhr Univ Bochum, Inst Theoret Phys, D-44780 Bochum, Germany. Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany. Univ St Andrews, Sch Math & Stat, St Andrews KY16 9SS, Fife, Scotland. RP Birn, J (reprint author), Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov; kg@astro.ku.dk; hesse@gsfc.nasa.gov; hoshino@eps.s.u-tokyo.ac.jp; huba@ppd.nrl.navy.mil; lapenta@lanl.gov; pritchet@physics.ucla.edu; kschindler1@aol.com; lyin@lanl.gov; buechner@mps.mpg.de; thomas@mcs.st-and.ac.uk; eric@mcs.st-and.ac.uk RI Buechner, Joerg/B-1213-2009; Neukirch, Thomas/C-1981-2009; Hesse, Michael/D-2031-2012; NASA MMS, Science Team/J-5393-2013; OI Neukirch, Thomas/0000-0002-7597-4980; NASA MMS, Science Team/0000-0002-9504-5214; Lapenta, Giovanni/0000-0002-3123-4024 NR 16 TC 67 Z9 67 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 25 PY 2005 VL 32 IS 6 AR L06105 DI 10.1029/2004GL022058 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 913LM UT WOS:000228153100001 ER PT J AU Yang, CR Shapiro, BE Hung, SP Mjolsness, ED Hatfield, GW AF Yang, CR Shapiro, BE Hung, SP Mjolsness, ED Hatfield, GW TI A mathematical model for the branched chain amino acid biosynthetic pathways of Escherichia coli K12 SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID GLOBAL GENE-EXPRESSION; COLI K-12; THREONINE DEAMINASE; DATABASE; 2-KETOBUTYRATE; METABOLISM; ISOLEUCINE; MECHANISM; PROTEIN; VALINE AB As a first step toward the elucidation of the systems biology of the model organism Escherichia coli, it was our goal to mathematically model a metabolic system of intermediate complexity, namely the well studied end product-regulated pathways for the biosynthesis of the branched chain amino acids L-isoleucine, L-valine, and L-leucine. This has been accomplished with the use of kMech (Yang, C.-R., Shapiro, B. E., Mjolsness, E. D., and Hatfield, G. W. (2005) Bioinformatics 21, in press), a Cellerator (Shapiro, B. E., Levchenko, A., Meyerowitz, E. M., Wold, B. J., and Mjolsness, E. D. (2003) Bioinformatics 19, 677-678) language extension that describes a suite of enzyme reaction mechanisms. Each enzyme mechanism is parsed by kMech into a set of fundamental association-dissociation reactions that are translated by Cellerator into ordinary differential equations. These ordinary differential equations are numerically solved by Mathematica (TM). Any metabolic pathway can be simulated by stringing together appropriate kMech models and providing the physical and kinetic parameters for each enzyme in the pathway. Writing differential equations is not required. The mathematical model of branched chain amino acid biosynthesis in E. coli K12 presented here incorporates all of the forward and reverse enzyme reactions and regulatory circuits of the branched chain amino acid biosynthetic pathways, including single and multiple substrate (Ping Pong and Bi Bi) enzyme kinetic reactions, feedback inhibition ( allosteric, competitive, and non-competitive) mechanisms, the channeling of metabolic flow through isozymes, the channeling of metabolic flow via transamination reactions, and active transport mechanisms. This model simulates the results of experimental measurements. C1 Univ Calif Irvine, Inst Genom & Bioinformat, Irvine, CA 92697 USA. Univ Calif Irvine, Sch Informat & Comp Sci, Irvine, CA 92697 USA. Univ Calif Irvine, Coll Med, Dept Microbiol & Mol Genet, Irvine, CA 92697 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mjolsness, ED (reprint author), Univ Calif Irvine, Inst Genom & Bioinformat, Irvine, CA 92697 USA. EM emj@uci.edu; gwhatfie@uci.edu FU NIGMS NIH HHS [GM55073, GM68903]; NLM NIH HHS [T15 LM-07443] NR 38 TC 28 Z9 30 U1 0 U2 3 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAR 25 PY 2005 VL 280 IS 12 BP 11224 EP 11232 DI 10.1074/jbc.M411471200 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 908BI UT WOS:000227761800043 PM 15657047 ER PT J AU Kalashnikova, OV Kahn, R Sokolik, IN Li, WH AF Kalashnikova, OV Kahn, R Sokolik, IN Li, WH TI Ability of multiangle remote sensing observations to identify and distinguish mineral dust types: Optical models and retrievals of optically thick plumes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC AEROSOLS; RADIATIVE PROPERTIES; INDIVIDUAL-PARTICLE; SCATTERING MATRICES; SIZE DISTRIBUTION; SENSITIVITY; OCEAN; SHAPE; NONSPHERICITY; WAVELENGTHS AB [1] We present a systematic theoretical study of atmospheric mineral dust radiative properties, focusing on implications for multiangle and multispectral remote sensing. We model optical properties of complex, nonspherical mineral dust mixtures in three visible-near-infrared satellite channels: 0.550, 0.672, and 0.866 mu m, accounting for recent field and laboratory data on mineral dust morphology and mineralogy. To model the optical properties of mineral dust, we employ the discrete dipole approximation technique for particles up to 2 mu m diameter and the T matrix method for particles up to 12 mu m. We investigate the impact of particle irregularity, composition, and size distribution on particle optical properties, and we develop optical models for representative natural mineral dust composition-size-shape types. Sensitivity studies with these models indicate that Multiangle Imaging Spectroradiometer (MISR) data should be able to distinguish plate-like from grain-like dust particles, weakly from strongly absorbing compositional types, and monomodal from bimodal size distributions. Models containing grain-like, weakly absorbing, bimodal distributions of dust particles were favored for optically thick Saharan and Asian dust plume examples, whereas strongly absorbing and plate-like particles were rejected. We will present detailed, systematic MISR sensitivity studies and analysis of more complex field cases using the optical models derived here in a future paper. C1 CALTECH, Jet Prop Lab, Natl Res Council, Pasadena, CA 91109 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Kalashnikova, OV (reprint author), CALTECH, Jet Prop Lab, Natl Res Council, MS 169-237,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM olga.v.kalashnikova@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 42 TC 70 Z9 72 U1 3 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 25 PY 2005 VL 110 IS D18 AR D18S14 DI 10.1029/2004JD004550 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 913MB UT WOS:000228154700001 ER PT J AU Xie, SC Zhang, MH Branson, M Cederwall, RT Del Genio, AD Eitzen, ZA Ghan, SJ Iacobellis, SF Johnson, KL Khairoutdinov, M Klein, SA Krueger, SK Lin, WY Lohmann, U Miller, MA Randall, DA Somerville, RCJ Sud, YC Walker, GK Wolf, A Wu, XQ Xu, KM Yio, JJ Zhang, G Zhang, JH AF Xie, SC Zhang, MH Branson, M Cederwall, RT Del Genio, AD Eitzen, ZA Ghan, SJ Iacobellis, SF Johnson, KL Khairoutdinov, M Klein, SA Krueger, SK Lin, WY Lohmann, U Miller, MA Randall, DA Somerville, RCJ Sud, YC Walker, GK Wolf, A Wu, XQ Xu, KM Yio, JJ Zhang, G Zhang, JH TI Simulations of midlatitude frontal clouds by single-column and cloud-resolving models during the Atmospheric Radiation Measurement March 2000 cloud intensive operational period SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LARGE-SCALE MODELS; GENERAL-CIRCULATION MODEL; RELAXED ARAKAWA-SCHUBERT; COMMUNITY CLIMATE MODEL; MOIST-CONVECTION; CUMULUS PARAMETERIZATION; MICROPHYSICAL PROCESSES; NUMERICAL-SIMULATION; STRATIFORM CLOUDS; WATER-CONTENT AB [1] This study quantitatively evaluates the overall performance of nine single-column models (SCMs) and four cloud-resolving models (CRMs) in simulating a strong midlatitude frontal cloud system taken from the spring 2000 Cloud Intensive Observational Period at the Atmospheric Radiation Measurement ( ARM) Southern Great Plains site. The evaluation data are an analysis product of constrained variational analysis of the ARM observations and the cloud data collected from the ARM ground active remote sensors (i.e., cloud radar, lidar, and laser ceilometers) and satellite retrievals. Both the selected SCMs and CRMs can typically capture the bulk characteristics of the frontal system and the frontal precipitation. However, there are significant differences in detailed structures of the frontal clouds. Both CRMs and SCMs overestimate high thin cirrus clouds before the main frontal passage. During the passage of a front with strong upward motion, CRMs underestimate middle and low clouds while SCMs overestimate clouds at the levels above 765 hPa. All CRMs and some SCMs also underestimated the middle clouds after the frontal passage. There are also large differences in the model simulations of cloud condensates owing to differences in parameterizations; however, the differences among intercompared models are smaller in the CRMs than the SCMs. In general, the CRM-simulated cloud water and ice are comparable with observations, while most SCMs underestimated cloud water. SCMs show huge biases varying from large overestimates to equally large underestimates of cloud ice. Many of these model biases could be traced to the lack of subgrid-scale dynamical structure in the applied forcing fields and the lack of organized mesoscale hydrometeor advections. Other potential reasons for these model errors are also discussed in the paper. C1 Lawrence Livermore Natl Lab, Atmospher Sci Div L103, Livermore, CA 94551 USA. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Pacific NW Natl Lab, Div Atmospher Sci, Richland, WA 99352 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Brookhaven Natl Lab, Dept Environm Sci, Upton, NY 11973 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Dalhousie Univ, Dept Phys & Atmospher Sci, Halifax, NS B3H 3J5, Canada. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Iowa State Univ, Dept Geol & Atmospher Sci, Ames, IA 50011 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Xie, SC (reprint author), Lawrence Livermore Natl Lab, Atmospher Sci Div L103, Livermore, CA 94551 USA. EM xie2@llnl.gov RI Del Genio, Anthony/D-4663-2012; Xu, Kuan-Man/B-7557-2013; Xie, Shaocheng/D-2207-2013; Wu, Xiangqian/F-5634-2010; Randall, David/E-6113-2011; Ghan, Steven/H-4301-2011; Klein, Stephen/H-4337-2016; Lohmann, Ulrike/B-6153-2009 OI Del Genio, Anthony/0000-0001-7450-1359; Xu, Kuan-Man/0000-0001-7851-2629; Xie, Shaocheng/0000-0001-8931-5145; Wu, Xiangqian/0000-0002-7804-5650; Randall, David/0000-0001-6935-4112; Ghan, Steven/0000-0001-8355-8699; Klein, Stephen/0000-0002-5476-858X; Lohmann, Ulrike/0000-0001-8885-3785 NR 78 TC 43 Z9 43 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 25 PY 2005 VL 110 IS D15 AR D15S03 DI 10.1029/2004JD005119 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 913LZ UT WOS:000228154500001 ER PT J AU Buczkowski, DL Frey, HV Roark, JH McGill, GE AF Buczkowski, DL Frey, HV Roark, JH McGill, GE TI Buried impact craters: A topographic analysis of quasi-circular depressions, Utopia Basin, Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID CRUSTAL DICHOTOMY; NORTHERN PLAINS; GIANT IMPACT; ORIGIN; EVOLUTION; LOWLANDS; PLANITIA; CONVECTION; POLYGONS; GRABENS AB [1] Many quasi-circular depressions (QCDs) revealed in the Mars Orbiter Laser Altimeter data set have no obvious structural representation in visible images of Mars. It has been suggested that these QCDs are surface representations of buried impact craters, and on the basis of this assumption, cumulative count versus diameter plots of QCDs in the northern lowlands have been constructed to date the buried lowland floor. If the QCDs are, in fact, buried impact craters, their surface relief should scale directly with their diameter; this relationship holds true for 115 QCDs with diameters ranging from 7 to 100 km within roughly 1500 km of the center of the Utopia Basin. The coefficient of determination ( R 2) of the relationship more closely approaches 1 when QCDs in zones of comparable cover thickness are evaluated. The surface relief versus diameter relationship of 55 randomly selected "pseudo-QCDs'' was also determined; their poor correlation indicates that the direct relationship of surface relief to diameter of actual QCDs is due to differential compaction of a cover material over buried impact craters and is not just a random effect of QCD diameter. The slope of the trend of the QCDs' surface relief versus diameter, when divided into zones of comparable cover thickness, can be used to determine which zones have thicker or thinner cover. C1 Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA. NASA, Geodynam Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Buczkowski, DL (reprint author), Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA. EM dbucz@geo.umass.edu; herbert.v.frey@.nasa.gov; james.h.roark.1@gsfc.nasa.gov; gmcgill@geo.umass.edu RI Buczkowski, Debra/I-7842-2015 OI Buczkowski, Debra/0000-0002-4729-7804 NR 33 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 24 PY 2005 VL 110 IS E3 AR E03007 DI 10.1029/2004JE002324 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 913MJ UT WOS:000228155600001 ER PT J AU Montmessin, F Fouchet, T Forget, F AF Montmessin, F Fouchet, T Forget, F TI Modeling the annual cycle of HDO in the Martian atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID GENERAL-CIRCULATION MODEL; HUBBLE-SPACE-TELESCOPE; SEASONAL WATER CYCLE; ICE CLOUDS; MARS; VAPOR; DEUTERIUM; PRECIPITATION; FRACTIONATION; ABUNDANCE AB [1] We present the results of the first three-dimensional (3-D) simulation of the water isotope HDO in the Martian atmosphere. This deuterated isotope of water has long been used on both Earth and Mars as a proxy to understand the climatic evolutions of these planets. On Mars, the current enrichment in deuterium concentration in the atmosphere is believed to be indirect evidence of a wetter climate in the past. Due to its vapor pressure being lower than that of H2O, HDO gets fractionated at condensation and therefore concentrates in the Martian water ice clouds. Our study aims at understanding the latitudinal, vertical, and temporal variations of this species under current Martian climate. Our results indicate that the globally averaged D/H ratio in the Martian atmosphere should vary modestly with season, with changes on the order of 2%. Locally, however, this same ratio exhibits large annual changes ( by a factor of 2) in the high-latitude regions. These fluctuations are controlled by the Polar Hood water ice clouds, within which HDO gets heavily fractionated. Due to the combined action of summer clouds above the north polar cap and to the cold-trapping effect of the south residual cap, the global atmospheric deuterium concentration is predicted to be more than 15% lower than the concentration in the north permanent cap ice. We thus extrapolate by suggesting that the "true'' D/H ratio of Martian water may exceed 6.5 (wrt. SMOW), rather than the 5.6 inferred from atmospheric probing. The globally and annually averaged vertical distribution of HDO exhibits a mild decline with altitude, a result in significant contrast with previous 1-D studies. These results will help constrain more accurately the photochemical models aimed at understanding the observed low concentration of deuterium at high altitudes and thus the process of water escape C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Observ Paris, LESIA, F-92125 Meudon, France. Inst Pierre Simon Laplace, Meteorol Dynam Lab, F-75252 Paris, France. RP Montmessin, F (reprint author), IPSL, CNRS, Serv Aeron, Aile 45-46,4eme Etage,Boite 102,4 Pl Jussieu, F-75252 Paris, France. EM montmes@aero.jussieu.fr RI Fouchet, Thierry/C-6374-2017 OI Fouchet, Thierry/0000-0001-9040-8285 NR 39 TC 40 Z9 40 U1 2 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 24 PY 2005 VL 110 IS E3 AR E03006 DI 10.1029/2004JE002357 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 913MJ UT WOS:000228155600002 ER PT J AU Muller, JR Aydin, A AF Muller, JR Aydin, A TI Using mechanical modeling to constrain fault geometries proposed for the northern Marmara Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID 1999 IZMIT EARTHQUAKE; POSITIONING SYSTEM MEASUREMENTS; MOMENT TENSOR INVERSION; STRIKE-SLIP FAULTS; ANATOLIAN FAULT; PULL-APART; ACTIVE TECTONICS; WESTERN TURKEY; GEOLOGICAL STRUCTURES; SEISMIC-REFLECTION AB [1] In recognition of potential seismic hazard along the North Anatolian fault within the Marmara Sea, geophysical surveys have recently been conducted to collect high-resolution bathymetry and seismic reflection data. Despite the high quality of the data, fault interpretations by different authors are varied and a conclusive fault geometry within the Marmara Sea remains elusive. This paper presents a mechanical modeling method for constraining proposed fault geometry interpretations. In the model, crustal faults within the Marmara Sea slip in accordance with GPS-constrained slip rates along deep plate boundary dislocations. We test three fault models proposed by others and show that an interpretation with a series of pull-apart basins along a master strike-slip fault best produces the observed deformation pattern within the Marmara Sea. The locations and relative subsidence of the basins along the northern Marmara trough are well matched. The computed slip vectors on the faults in the best fitting model indicate that, except for small faults bounding the Tekirdag. basin, the faults have dominantly right-lateral slip, with rakes within 15 degrees of horizontal. On the local scale, this suggests that interaction between the segmented strike-slip faults is the dominant mechanism producing the observed vertical deformation in the Marmara Sea. On the regional scale, if the Marmara Sea faults behaved in this manner over geologic timescales, then right-lateral plate boundary motion, without an additional component of north-south extension associated with the Aegean Sea, is sufficient to produce the Marmara Sea pull-apart basin morphology. C1 Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. RP Muller, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 921, Greenbelt, MD 20771 USA. EM jmuller@core2.gsfc.nasa.gov NR 64 TC 24 Z9 25 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 23 PY 2005 VL 110 IS B3 AR B03407 DI 10.1029/2004JB003226 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 913MM UT WOS:000228155900002 ER PT J AU Hadjiev, VG Mitchell, CA Arepalli, S Bahr, JL Tour, JM Krishnamoorti, R AF Hadjiev, VG Mitchell, CA Arepalli, S Bahr, JL Tour, JM Krishnamoorti, R TI Thermal mismatch strains in sidewall functionalized carbon nanotube/polystyrene nanocomposites SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GLASS-TRANSITION; NANOTUBES; RAMAN; POLYSTYRENE; COMPOSITES; FILMS AB We present an unusual temperature dependence of thermal strains in 4-(10-hydroxy)decyl benzoate (HDB) modified SWNT/PS (SWNT-single wall carbon nanotube, PS-polystyrene) nanocomposites. The strain transfer from the matrix to nanotubes in these nanocomposites, inferred from the frequency change of the Raman active tangential modes of the nanotubes, is enhanced strongly below 300 K, whereas it is vanishingly small at higher temperatures. The increased strain transfer is suggestive of reinforcement of the HDB-SWNT/PS nanocomposites at low temperatures. On the other hand, the pristine SWNTs couple weakly to the PS matrix over the entire temperature range of 4.5-410 K. We argue that the strain transfer in HDB-SWNT/PS is determined by the thermomechanical properties of the interface region composed of polystyrene plasticized by the tethered alkanelike modifier. C1 Univ Houston, Texas Ctr Supercond & Adv Mat, Houston, TX 77204 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. GB Tech, NASA, Johnson Space Ctr, Houston, TX 77058 USA. Rice Univ, Dept Chem, Dept Chem Engn & Mat Sci, Houston, TX 77005 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77005 USA. RP Hadjiev, VG (reprint author), Univ Houston, Texas Ctr Supercond & Adv Mat, Houston, TX 77204 USA. RI Arepalli, Sivaram/A-5372-2010; Krishnamoorti, Ramanan/F-7914-2011; Hadjiev, Viktor/A-7069-2008; OI Krishnamoorti, Ramanan/0000-0001-5831-502X; Hadjiev, Viktor/0000-0001-8579-9357; Tour, James/0000-0002-8479-9328 NR 23 TC 16 Z9 18 U1 0 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 22 PY 2005 VL 122 IS 12 AR 124708 DI 10.1063/1.1874912 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 915HD UT WOS:000228287900048 PM 15836410 ER PT J AU Tanskanen, EI Slavin, JA Fairfield, DH Sibeck, DG Gjerloev, J Mukai, T Ieda, A Nagai, T AF Tanskanen, EI Slavin, JA Fairfield, DH Sibeck, DG Gjerloev, J Mukai, T Ieda, A Nagai, T TI Magnetotail response to prolonged southward IMF B-z intervals: Loading, unloading, and continuous magnetospheric dissipation SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMA SHEET; SOLAR-WIND; GEOTAIL OBSERVATIONS; MAGNETIC-FIELD; SUBSTORMS; CONVECTION; FLOW; SPACECRAFT; SATELLITE; PRESSURE AB [ 1] The response of the Earth's magnetotail to prolonged southward interplanetary magnetic field ( IMF) has been determined for the three Geotail magnetotail seasons from November to April, 1999 - 2002. We examine the total magnetotail pressure P-T,P-tail = B-2/2 mu(0) + N(i)kT(i) because variations should be similar in this parameter in the lobes and in the plasma sheet. We found 13 events when IMF B-z remained southward for 8 hours or longer and Geotail was located within the magnetotail farther than 10 RE downstream. All 13 events were subdivided into separate intervals characterized as ( 1) loading, if the tail total pressure increased more than 100%; ( 2) unloading, if the total pressure decreased by more than 50%; and ( 3) what we term here continuous magnetospheric dissipation (CMD), if the tail total pressure increased by less than 100% and/or decreased less than 50% during the entire mode interval. In total, 37 loading, 37 unloading, and 28 CMD events were found. The plasma sheet magnetic flux transfer rate, phi(Earth) approximate to v(x) center dot B-z, and plasma bulk velocity has been analyzed to determine the steadiness of the plasma sheet convection. Plasma sheet convection was found to be highly disturbed and intense plasma flows (BBFs and FBs) were observed during all convection states. However, the occurence rate and amplitude of plasma flows distinguish loading-unloading and continuous dissipation periods from each other. BBFs seem to be more numerous ( 135) but weaker ( about 500 km/s) during continuous dissipation intervals compared with BBFs existing during unloading mode ( 61 and 660 km/s). Finally, it was found that CMD-type convection is more likely when the mean southward IMF B-z > - 5 nT, while loading-unloading is more likely when IMF B-z < - 5 nT. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Tokyo Inst Technol, Dept Earth & Planetary Sci, Tokyo 1528551, Japan. RP Tanskanen, EI (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 696, Greenbelt, MD 20770 USA. EM etanskanen@lepvax.gsfc.nasa.gov RI Sibeck, David/D-4424-2012; Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 35 TC 26 Z9 26 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 22 PY 2005 VL 110 IS A3 AR A03216 DI 10.1029/2004JA010561 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 913MU UT WOS:000228156700003 ER PT J AU Farassat, F AF Farassat, F TI Comments on the paper by Zinoviev and Bies "On acoustic radiation by a rigid object in a fluid flow" SO JOURNAL OF SOUND AND VIBRATION LA English DT Editorial Material ID SURFACES; SOUND C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Farassat, F (reprint author), NASA, Langley Res Ctr, MS 461, Hampton, VA 23681 USA. EM feri.farassat@nasa.gov NR 12 TC 5 Z9 6 U1 1 U2 2 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD MAR 22 PY 2005 VL 281 IS 3-5 BP 1217 EP 1223 DI 10.1016/j.jsv.2004.05.025 PG 7 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 901UX UT WOS:000227308700040 ER PT J AU Stolc, V Samanta, MP Tongprasit, W Sethi, H Liang, SD Nelson, DC Hegeman, A Nelson, C Rancour, D Bednarek, S Ulrich, EL Zhao, Q Wrobel, RL Newman, CS Fox, BG Phillips, GN Markley, JL Sussman, MR AF Stolc, V Samanta, MP Tongprasit, W Sethi, H Liang, SD Nelson, DC Hegeman, A Nelson, C Rancour, D Bednarek, S Ulrich, EL Zhao, Q Wrobel, RL Newman, CS Fox, BG Phillips, GN Markley, JL Sussman, MR TI Identification of transcribed sequences in Arabidopsis thaliana by using high-resolution genome tiling arrays SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE higher plant; transcriptome; maskless array synthesizer ID GENE-EXPRESSION; TRANSCRIPTIONAL ACTIVITY; RNA; MAP AB Using a maskless photolithography method, we produced DNA oligonucleotide microarrays with probe sequences tiled throughout the genome of the plant Arabidopsis thaliana. RNA expression was determined for the complete nuclear, mitochondrial, and chloroplast genomes by tiling 5 million 36-mer probes. These probes were hybridized to labeled mRNA isolated from liquid grown T87 cells, an undifferentiated Arabidopsis cell culture line. Transcripts were detected from at least 60% of the nearly 26,330 annotated genes, which included 151 predicted genes that were not identified previously by a similar genome-wide hybridization study on four different cell lines. In comparison with previously published results with 25-mer tiling arrays produced by chromium masking-based photolithography technique, 36-mer oligonucleotide probes were found to be more useful in identifying intron-exon boundaries. Using two-dimensional HPLC tandem mass spectrometry, a small-scale proteomic analysis was performed with the same cells. A large amount of strongly hybridizing RNA was found in regions "antisense" to known genes. Similarity of antisense activities between the 25-mer and 36-mer data sets suggests that it is a reproducible and inherent property of the experiments. Transcription activities were also detected for many of the intergenic regions and the small RNAs, including tRNA, small nuclear RNA, small nucleolar RNA, and microRNA. Expression of tRNAs correlates with genome-wide amino acid usage. C1 NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 USA. Univ Wisconsin, Ctr Eukaryot Struct Genom, Madison, WI 53706 USA. RP Stolc, V (reprint author), NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. EM vstolc@mail.arc.nasa.gov; manoj.samanta@systemix.org RI Hegeman, Adrian/D-5984-2013; OI Hegeman, Adrian/0000-0003-1008-6066; Nelson, David/0000-0001-9792-5015 NR 20 TC 111 Z9 118 U1 0 U2 7 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAR 22 PY 2005 VL 102 IS 12 BP 4453 EP 4458 DI 10.1073/pnas.0408203102 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 909IY UT WOS:000227854800043 PM 15755812 ER PT J AU Exton, RJ Popovic, S Herring, GC Cooper, M AF Exton, RJ Popovic, S Herring, GC Cooper, M TI Levitation using microwave-induced plasmas SO APPLIED PHYSICS LETTERS LA English DT Article AB The levitation of objects above a microwave horn is demonstrated. High-power microwave pulses generate a low-temperature, diffuse plasma on the surface of the horn window. The thermal effect of the surface plasma brings about a localized increase in the pressure and results in a vertical flow of air, thus levitating the object. (C) 2005 American Institute of Physics. C1 NASA, Adv Sensing & Opt Measurement Branch, Res & Technol Directorate, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. RP Exton, RJ (reprint author), NASA, Adv Sensing & Opt Measurement Branch, Res & Technol Directorate, Langley Res Ctr, Hampton, VA 23681 USA. EM r.j.exton@larc.nasa.gov NR 11 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 21 PY 2005 VL 86 IS 12 AR 124103 DI 10.1063/1.1887837 PG 2 WC Physics, Applied SC Physics GA 912BA UT WOS:000228050900098 ER PT J AU Matsko, AB Strekalov, DV Maleki, L AF Matsko, AB Strekalov, DV Maleki, L TI On the dynamic range of optical delay lines based on coherent atomic media SO OPTICS EXPRESS LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; NONLINEAR OPTICS; GROUP-VELOCITY; LIGHT; VAPOR; SLOW; PROPAGATION; ULTRASLOW; STORAGE; SYSTEM AB We show that the dynamic range of delay lines based on slow light propagation in atomic coherent media is restricted due to absorptive, dispersive, and nonlinear properties of the media. We compare the electromagnetically induced transparency based delay lines with optical fiber and resonator delays. (C) 2005 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 32 TC 50 Z9 52 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAR 21 PY 2005 VL 13 IS 6 BP 2210 EP 2223 DI 10.1364/OPEX.13.002210 PG 14 WC Optics SC Optics GA 908QZ UT WOS:000227805400055 PM 19495109 ER PT J AU Sellar, RG Boreman, GD AF Sellar, RG Boreman, GD TI Comparison of relative signal-to-noise ratios of different classes of imaging spectrometer SO APPLIED OPTICS LA English DT Article ID DESIGN AB The continued development of new and fundamentally different classes of imaging spectrometer has increased both the scope and the complexity of comparisons of their relative signal-to-noise ratios. Although the throughput and multiplex advantages of Fourier-transform spectrometers were established in the early 1950s, the application of this terminology to imaging spectrometers is often ambiguous and has led to some confusion and debate. For comparisons of signal-collection abilities to be useful to a system designer, they must be based on identical requirements and constraints. We present unambiguous definitions of terminology for application to imaging spectrometers and comparisons of signal-collection abilities and signal-to-noise-ratios on a basis that is useful to a systems designer and inclusive of six fundamentally different classes (both traditional and novel) of imaging spectrometers. (c) 2005 Optical Society of America. C1 Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. Univ Cent Florida, Ctr Res & Educ Opt & Lasers, Sch Opt, Orlando, FL 32816 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 171-B1, Pasadena, CA 91109 USA. EM glenn.sellar@jpl.nasa.gov NR 15 TC 40 Z9 43 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2005 VL 44 IS 9 BP 1614 EP 1624 DI 10.1364/AO.44.001614 PG 11 WC Optics SC Optics GA 907ZY UT WOS:000227758000014 PM 15813264 ER PT J AU Kazadzis, S Bais, A Kouremeti, N Gerasopoulos, E Garane, K Blumthaler, M Schallhart, B Cede, A AF Kazadzis, S Bais, A Kouremeti, N Gerasopoulos, E Garane, K Blumthaler, M Schallhart, B Cede, A TI Direct spectral measurements with a Brewer spectroradiometer: absolute calibration and aerosol optical depth retrieval SO APPLIED OPTICS LA English DT Article ID SOLAR UV IRRADIANCE; ROTATING SHADOWBAND RADIOMETER; ULTRAVIOLET-RADIATION CAMPAIGN; ACTINIC FLUX; B RADIATION; PHOTOCHEMICAL ACTIVITY; OZONE MEASUREMENTS; SPECTROPHOTOMETER; SCATTERING; TURBIDITY AB We present three different methods for the absolute calibration of direct spectral irradiances measured with a Brewer spectroradiometer, which are shown to agree to within +/- 2%. Direct irradiance spectra derived by Brewer and Bentham spectroradiometers agree to within 4 +/- 3%. Good agreement was also found by a comparison of the aerosol optical depth and Angstrom exponent retrieved by the two instruments and a multifilter rotational shadowband radiometer. The spectral aerosol optical depth (300-365 nm) derived from six years of direct irradiance measurements at Thessaloniki shows a distinct seasonal variation, averaging to similar to 0.3 at 340 nm in winter and similar to 0.7 in summer. (c) 2005 Optical Society of America. C1 Aristotle Univ Thessaloniki, Lab Atmospher Phys, Thessaloniki 54124, Greece. Univ Innsbruck, Inst Med Phys, A-6020 Innsbruck, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Aristotle Univ Thessaloniki, Lab Atmospher Phys, POB 149, Thessaloniki 54124, Greece. EM skaza@skiathos.physics.auth.gr RI Kazadzis, Stelios/A-5628-2011; Kazadzis, Stelios/F-8667-2011; Bais, Alkiviadis/D-2230-2009; OI Bais, Alkiviadis/0000-0003-3899-2001; Kazadzis, Stelios/0000-0002-8624-8247 NR 54 TC 42 Z9 42 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2005 VL 44 IS 9 BP 1681 EP 1690 DI 10.1364/AO.44.001681 PG 10 WC Optics SC Optics GA 907ZY UT WOS:000227758000021 PM 15813271 ER PT J AU Krebs, DJ Novo-Gradac, AM Li, SX Lindauer, SJ Afzal, RS Yu, AW AF Krebs, DJ Novo-Gradac, AM Li, SX Lindauer, SJ Afzal, RS Yu, AW TI Compact, passively Q-switched Nd : YAG laser for the MESSENGER mission to Mercury SO APPLIED OPTICS LA English DT Article AB A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter, an instrument on the Mercury Surface, Space Environment, Geochemistry, and Ranging mission to the planet Mercury. The laser achieves 5.4% efficiency with a near-diffraction-limited beam. It passed all space-flight environmental tests at subsystem, instrument, and satellite integration testing and successfully completes a postlaunch aliveness check en route to Mercury. The laser design draws on a heritage of previous laser altimetry missions, specifically the Ice Cloud and Elevation Satellite and the Mars Global Surveyor, but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury. (c) 2005 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Northrop Grumman Laser Syst, Apopka, FL 32703 USA. Spectra Syst Corp, Providence, RI 02903 USA. Northrop Grumman Elect Syst, Linthicum, MD 21090 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 10 TC 57 Z9 62 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2005 VL 44 IS 9 BP 1715 EP 1718 DI 10.1364/AO.44.001715 PG 4 WC Optics SC Optics GA 907ZY UT WOS:000227758000026 PM 15813276 ER PT J AU Ramos-Izquierdo, L Scott, VS Schmidt, S Britt, J Mamakos, W Trunzo, R Cavanaugh, J Miller, R AF Ramos-Izquierdo, L Scott, VS Schmidt, S Britt, J Mamakos, W Trunzo, R Cavanaugh, J Miller, R TI Optical system design and integration of the Mercury Laser Altimeter SO APPLIED OPTICS LA English DT Article ID MESSENGER MISSION AB The Mercury Laser Altimeter (MLA), developed for the 2004 MESSENGER mission to Mercury, is designed to measure the planet's topography by laser ranging. A description of the MLA optical system and its measured optical performance during instrument-level and spacecraft-level integration and testing are presented. (c) 2005 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Electromech Syst Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Elect Syst Branch, Greenbelt, MD 20771 USA. LRI, Opt Design, Washington, DC USA. Sigma Space Corp, Lanham, MD 20706 USA. Design Interface Inc, Finksburg, MD 21048 USA. Swales Aerosp, Beltsville, MD 20705 USA. RP NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. EM Lramos@pop900.gsfc.nasa.gov RI Scott, Vibart/B-5086-2013 NR 12 TC 15 Z9 20 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2005 VL 44 IS 9 BP 1748 EP 1760 DI 10.1364/AO.44.001748 PG 13 WC Optics SC Optics GA 907ZY UT WOS:000227758000030 PM 15813279 ER EF