FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Tsurutani, BT Kamide, Y Arballo, JK Gonzalez, WD Lepping, RP AF Tsurutani, BT Kamide, Y Arballo, JK Gonzalez, WD Lepping, RP TI Interplanetary causes of great and superintense magnetic storms SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID GEOMAGNETIC-ACTIVITY; ORIGIN; CLOUDS AB We examine possible interplanetary mechanisms for the creation of the largest magnetic storms at the Earth. We consider the effects of interplanetary shock events on magnetic cloud and sheath plasma. We also examine the effects of a combination of a long-duration southward sheath magnetic field, followed by a magnetic cloud B-S event. Examination of profiles of the most intense storms from 1957 to the present indicate that the latter (double IMF B-Z events) is an important cause of superintense D-ST events. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Aichi 442, Japan. Inst Nacl Pesquisas Espaciais, BR-12201 Sao Jose Dos Campos, SP, Brazil. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 28 Z9 28 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 101 EP 105 DI 10.1016/S1464-1917(98)00015-4 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800015 ER PT J AU Vassiliadis, D Klimas, AJ Baker, DN AF Vassiliadis, D Klimas, AJ Baker, DN TI Models of D-st geomagnetic activity and of its coupling to solar wind parameters SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID RING-CURRENT; FIELD; DST AB Nonlinear filters have provided high-accuracy predictions of geomagnetic activity indices from solar wind key parameters. Here we extend the nonlinear prediction methods to derive closed-form analytical models for the solar wind-geomagnetic coupling. For each phase of either storm or magnetopause compression as identified by D-st, we calculate nonlinear, piecewise-constant models of the relation between the ring current index D-st and the solar wind electric field components. The time scales of storm main phase and recovery depend on storm phase, and the presence of solar wind VBs and pressure. Then, going beyond piecewise constant models, we use state space methods to reveal the fine structure of the D-st dynamics in detail. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NR 15 TC 14 Z9 14 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 107 EP 112 DI 10.1016/S1464-1917(98)00016-6 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800016 ER PT J AU Curtis, S Raeder, J Berchem, J Goodrich, C Wiltberger, M Greenwald, R Baker, K Roble, R AF Curtis, S Raeder, J Berchem, J Goodrich, C Wiltberger, M Greenwald, R Baker, K Roble, R TI A global view of the role of acceleration processes in solar-terrestrial coupling as provided by the ISTP theory and ground-based experiments SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; MAGNETOSPHERE; MAGNETOTAIL; EVENTS; MODELS; SHEET; FLOW AB Present global simulations of the Earth's upper atmosphere and magnetosphere, which have been developed under the auspices of the International Solar Terrestrial Physics (ISTP) Program, can provide an effective, near-quantitative, global view of the role of acceleration processes in the transport of energy, momentum, and mass from the solar wind, through the magnetosphere, and to their final deposition in the upper atmosphere. In addition, ground-based experiments can provide not only more realistic inner boundary-conditions for the global MHD magnetosphere simulations, but give improved estimates of the roles of magnetospheric acceleration processes in the upper atmosphere. An overview of a detailed case study of a series of events which occurred during 19-20 May 1996 will be used to illustrate the power of theory and ground-based observations to complement spacecraft observations in providing a global view of acceleration processes. The period from 0100 UT 19 May to 0300 UT 20 May 1996 was chosen as an illustrative case since it contains times of steady solar wind conditions, and periods of slow variations in the IMF followed by sudden changes in the IMF These conditions are near ideal for global simulation-observation comparisons. It also has two distinct substorms at 2020 UT 19 May and 0035 UT 20 May. The slow changes in the IMF followed by the rapid changes provided excellent conditions for comparing theoretical predictions of the global effects of acceleration processes and observations from ground-based and spacecraft experiments. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, IGPP, Los Angeles, CA 90024 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Curtis, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Wiltberger, Michael/B-8781-2008; OI Wiltberger, Michael/0000-0002-4844-3148; Greenwald, Raymond/0000-0002-7421-5536 NR 24 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 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 1-3 BP 239 EP 246 DI 10.1016/S1464-1917(98)00035-X PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LM UT WOS:000082711800035 ER PT J AU Bilitza, D Hernandez-Pajares, M Juan, JM Sanz, J AF Bilitza, D Hernandez-Pajares, M Juan, JM Sanz, J TI Comparison between IRI and GPS-IGS derived electron content during 1991-97 SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID GLOBAL POSITIONING SYSTEM; IONOSPHERE AB The existence of a permanent network of GPS ground receivers, the International GPS Service (IGS), with available data since 1991, allows to perform an exhaustive comparison of the global electron content derived from these data using tomographic models with the International Reference Ionosphere (IRI) predictions. This work will allow the IRI upgrading for the electron content forecast, using this data set at global scale and along more than half solar cycle. In this contribution we present a comparison involving more than 1300 stations times day worldwide distributed between 1991 (similar or equal to 10 stations) and 1997 (similar or equal to 200 stations). (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Politecn Catalunya, ES-08034 Barcelona, Spain. NASA, Goddard Space Flight Ctr, RSTX, Greenbelt, MD 20771 USA. RP Hernandez-Pajares, M (reprint author), Univ Politecn Catalunya, Jordi Girona 1-3,Mpd C-3 B-4,Campus Nord, ES-08034 Barcelona, Spain. RI Sanz Subirana, Jaume/C-1265-2014; Juan Zornoza, Jose Miguel/S-6224-2016 OI Sanz Subirana, Jaume/0000-0001-8880-7084; Juan Zornoza, Jose Miguel/0000-0003-1126-2367 NR 14 TC 8 Z9 8 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 4 BP 311 EP 319 DI 10.1016/S1464-1917(99)00004-5 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 238LN UT WOS:000082711900003 ER PT J AU Gelino, CR Marley, M Stephens, D Lunine, J Freedman, R AF Gelino, CR Marley, M Stephens, D Lunine, J Freedman, R TI Model bond albedos of extrasolar giant planets SO PHYSICS AND CHEMISTRY OF THE EARTH PART C-SOLAR-TERRESTIAL AND PLANETARY SCIENCE LA English DT Article ID COMPANION; JUPITER AB The atmospheres of extrasolar giant planets are modeled with various effective temperatures and gravities, with and without clouds. Bond albedos are computed by calculating the ratio of the flux reflected by a planet (integrated over wavelength) to the total stellar flux incident on the planet. This quantity is useful for estimating the effective temperature and evolution of a planet. We find it is sensitive to the stellar type of the primary. For a 5 M-Jup planet the Bond albedo varies from 0.4 to 0.3 to 0.06 as the primary star varies from A5V to G2V to M2V in spectral type. It is relatively insensitive to the effective temperature and gravity for cloud-free planets. Water clouds increase the reflectivity of the planet in the red, which increases the Bond albedo. The Bond albedo increases by an order of magnitude for a 13 M-Jup planet with an M2V primary when eater clouds are present. Silicate clouds, on the other hand, can either increase or decrease the Bond albedo, depending on whether there are many small grains (the former) or few large grains (the latter). (C) 1999 Elsevier Science Ltd. All rights reserved. C1 New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Inst Astrophys, Reparto Planetol, Rome, Italy. NASA, Ames Res Ctr, Space Phys Res Inst, Moffett Field, CA 94035 USA. RP Gelino, CR (reprint author), New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. NR 8 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 1464-1917 J9 PHYS CHEM EARTH PT C JI Phys. Chem. Earth Pt. C-Solar-Terr. Planet. Sci. PY 1999 VL 24 IS 5 BP 573 EP 578 DI 10.1016/S1464-1917(99)00094-X PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 250FX UT WOS:000083379300029 ER PT S AU Goorjian, PM Ning, CZ AF Goorjian, PM Ning, CZ BE Blood, P Ishibashi, A Osinski, M TI Transverse mode dynamics of VCSELs through space-time domain simulation SO PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Physics and Simulation of Optoelectronic Devices VII CY JAN 25-29, 1999 CL SAN JOSE, CA SP SPIE, Def Adv Res Projects Agcy DE VCSELs; transverse mode dynamics; computational modeling; space-time domain simulation ID SURFACE-EMITTING LASERS; SEMICONDUCTOR-LASERS AB An approximation to the Maxwell-Semiconductor Bloch equations is used to model transverse mode dynamics of vertical-cavity surface-emitting lasers (VCSELs). The time-evolution of the spatial profiles of the laser field and carrier density is solved by a finite-difference algorithm. The algorithm is fairly general; it can handle devices of any shape, which are either gain or index guided or both. Also there is no a priori assumption about the type or number of modes. The physical modeling includes the nonlinear carrier dependence of the optical gain and refractive index and dispersion effects on the gain and the refractive index are also included. The modeling of the optical susceptibility is based on first-principles and includes device details such as the quantum well structures, and also includes many-body effects. Temporal dynamics as fast as on a picosecond scale can be resolved. The influences of the shape of the pumping region and of the index confinement on the transverse mode dynamics are investigated. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Goorjian, PM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3095-1 J9 P SOC PHOTO-OPT INS PY 1999 VL 3625 BP 395 EP 401 DI 10.1117/12.356898 PG 7 WC Optics SC Optics GA BN77L UT WOS:000082883300041 ER PT S AU Dzegilenko, FN AF Dzegilenko, FN BE Blood, P Ishibashi, A Osinski, M TI Energetics and dynamics of GaAs epitaxial growth via quantum wave packet studies SO PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Physics and Simulation of Optoelectronic Devices VII CY JAN 25-29, 1999 CL SAN JOSE, CA SP SPIE, Def Adv Res Projects Agcy DE MBE growth; gallium arsenide; density functional theory; wave packet dynamics ID ENERGY ELECTRON-DIFFRACTION; EFFECTIVE CORE POTENTIALS; MOLECULAR-BEAM EPITAXY; DISCRETE VARIABLE REPRESENTATIONS; DEPENDENT SCHRODINGER-EQUATION; INTENSITY OSCILLATIONS; INTERACTION KINETICS; CRYSTAL-GROWTH; CLUSTER MODEL; MONTE-CARLO AB The dynamics of incorporation of AS:! molecule into the flat GaAs(100) surface is studied computationally using the combination of density functional theory and quantum wave packet dynamics. The two-dimensional potential energy surface (PES) describing the interaction of incoming As-2 molecular beam with the GaAs surface is calculated using the density functional theory. Two coordinates include the internuclear As-As distance and the distance between the As-2 center of mass and Ga atom of GaAs surface. The GaAs surface is represented by a cluster of 40 atoms. The computed PES shows a significant barrier (around I eV) in the entrance channel and a strongly bound molecular chemisorption site indicating the importance of quantum effects. The time-dependent Schrodinger equation is solved on a 75 x 751 rectangular grid by expanding the wave packet in a discrete variable representation basis and propagating it in time using the Chebyshev expansion algorithm. The probabilities of trapping and subsequent dissociation of the molecular As-2 bond are calculated as a function of beam translational energy and the vibrational quantum number of As-2. C1 NASA, Ames Res Ctr, MRJ, Moffett Field, CA 94035 USA. RP Dzegilenko, FN (reprint author), NASA, Ames Res Ctr, MRJ, MS T27-A1, Moffett Field, CA 94035 USA. NR 36 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3095-1 J9 P SOC PHOTO-OPT INS PY 1999 VL 3625 BP 459 EP 465 DI 10.1117/12.356904 PG 7 WC Optics SC Optics GA BN77L UT WOS:000082883300047 ER PT S AU Meyyappan, M Bose, D AF Meyyappan, M Bose, D BE Blood, P Ishibashi, A Osinski, M TI Reactor and process modeling in optoelectronics device fabrication SO PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Physics and Simulation of Optoelectronic Devices VII CY JAN 25-29, 1999 CL SAN JOSE, CA SP SPIE, Def Adv Res Projects Agcy DE reactor model; deposition; etching; computer simulation; nitride growth; chlorine plasma chemistry; virtual reactor ID CHEMICAL-VAPOR-DEPOSITION; DISCHARGES AB Computational modeling of reactors and processes has gained wide acceptance in the microelectronics industry. Commercial software are readily available and routinely used at the design stage to reduce design cycle and cost of development. The optoelectronics community can benefit from these advances since many of the processing steps are common, though material chemistries, device configuration and wafer size are different. This paper provides an overview of reactor and process models and specific applications to nitride MOCVD, hydride vapor epitaxy of GaN, SiC CVD and etching of m-V compounds using chlorine chemistry. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Meyyappan, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3095-1 J9 P SOC PHOTO-OPT INS PY 1999 VL 3625 BP 466 EP 474 DI 10.1117/12.356905 PG 9 WC Optics SC Optics GA BN77L UT WOS:000082883300048 ER PT S AU Ning, CZ AF Ning, CZ BE Blood, P Ishibashi, A Osinski, M TI Validity of the relation between spontaneous and stimulated emissions in semiconductors SO PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES VII SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Physics and Simulation of Optoelectronic Devices VII CY JAN 25-29, 1999 CL SAN JOSE, CA SP SPIE, Def Adv Res Projects Agcy ID AMPLIFIED SPONTANEOUS EMISSION; QUANTUM-WELL LASERS; GAIN; SPECTRA AB Validity of the relation between spontaneous emission and stimulated emission (or gain) in a semiconductor is revisited. It is shown that this relation, while exact for the case of zero-linewidth, is in general not valid for all the commonly used lineshapes at low excitation levels. At high excitation levels well beyond the transparency density, the validity is almost exact for the Gauss- and Sech-lineshapes. Even at high excitation level, this relation is still not valid for the Lorentzian lineshape. The convoluted Lorentzian lineshape, for which the relation between stimulated and spontaneous emissions is exactly valid, is shown to allow an effective lineshape function which can be expressed explicitly in terms of elementary functions. C1 NASA, Ames Res Ctr, Computat Quantum Optoelect, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Computat Quantum Optoelect, MS-T27A-1, Moffett Field, CA 94035 USA. EM cning@nas.nasa.gov NR 19 TC 4 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3095-1 J9 PROC SPIE PY 1999 VL 3625 BP 622 EP 632 DI 10.1117/12.356922 PG 11 WC Optics SC Optics GA BN77L UT WOS:000082883300064 ER PT J AU Kruger, H Grun, E Hamilton, DP Baguhl, M Dermott, S Fechtig, H Gustafson, BA Hanner, MS Horanyi, M Kissel, J Lindblad, BA Linkert, D Linkert, G Mann, I McDonnell, JAM Morfill, GE Polanskey, C Riemann, R Schwehm, G Srama, R Zook, HA AF Kruger, H Grun, E Hamilton, DP Baguhl, M Dermott, S Fechtig, H Gustafson, BA Hanner, MS Horanyi, M Kissel, J Lindblad, BA Linkert, D Linkert, G Mann, I McDonnell, JAM Morfill, GE Polanskey, C Riemann, R Schwehm, G Srama, R Zook, HA TI Three years of Galileo dust data: II. 1993-1995 SO PLANETARY AND SPACE SCIENCE LA English DT Article ID INTERSTELLAR DUST; ULYSSES; JUPITER; STREAMS; DETECTOR AB Between January 1993-December 1995, the Galileo spacecraft traversed interplanetary space between Earth and Jupiter and arrived at Jupiter on 7 December 1995. The dust instrument onboard the spacecraft was operating during most of the time and data from the instrument were obtained via memory readouts which occurred at rates between twice per day and once per week. All events were classified by an onboard program into 24 categories. Noise events were usually restricted to the lowest categories (class 0). During Galileo's passage through Jupiter's radiation belts on 7 December 1995, several of the higher categories (classes 1 and 2) also show evidence for contamination by noise. The highest categories (class 3) were noise-free all the time. A relatively constant impact rate of interplanetary and interstellar (big) particles of 0.4 impacts per day was detected over the whole three-year time span. In the outer solar system (outside about 2.6 AU) they are mostly of interstellar origin, whereas in the inner solar system they are mostly interplanetary particles. Within about 1.7 AU from Jupiter intense streams of small dust particles were detected with impact rates of up to 20,000 per day whose impact directions are compatible with a Jovian origin. Two different populations of dust particles were detected in Jovian magnetosphere: small stream particles during Galileo's approach to the planet and big particles concentrated closer to Jupiter between the Galilean satellites. There is strong evidence that the dust stream particles are orders of magnitude smaller in mass and faster than the instrument's calibration, whereas the calibration is valid for the big particles. Because the data transmission rate was very low, the complete data set for only a small fraction (2525) of all detected particles could be transmitted to Earth; the other particles were only counted. Together with the 358 particles published earlier, information about 2883 particles detected by the dust instrument during Galileo's six years' journey to Jupiter is now available. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Maryland, College Pk, MD 20742 USA. Univ Florida, Gainesville, FL 32611 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Lund Observ, S-221 Lund, Sweden. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Kent, Canterbury CT2 7NR, Kent, England. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. European Space Technol Ctr, NL-2200 AG Noordwijk, Netherlands. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Kruger, H (reprint author), Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. RI Gustafson, Bo/B-9526-2011 NR 26 TC 24 Z9 24 U1 1 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 JAN-FEB PY 1999 VL 47 IS 1-2 BP 85 EP 106 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 179JT UT WOS:000079324100011 ER PT J AU Laxton, NF Balogh, A Cowley, SWH Dunlop, MW Hynds, RJ McComas, DJ Phillips, JL AF Laxton, NF Balogh, A Cowley, SWH Dunlop, MW Hynds, RJ McComas, DJ Phillips, JL TI Ulysses observations of field-perpendicular plasma flows in the Jovian magnetosphere: comparison of ExB velocity vectors derived from energetic ion and thermal electron data SO PLANETARY AND SPACE SCIENCE LA English DT Article ID HOT IONS; ANISOTROPY; JUPITER; MAGNETODISC; COROTATION; DEPARTURE; PROTONS; TORUS; MODEL AB The ExB velocity vectors which correspond to the field-perpendicular flow of the low-energy plasma have been independently derived for the Ulysses flyby of Jupiter using energetic ion and thermal electron data. In this paper these measurements are compared. It is shown that reasonable quantitative agreement exists during the prenoon inbound pass, though with some significant differences. Both data sets indicate the presence of slow field-perpendicular flows in the dayside outer magnetosphere (similar to 80-110 R-J), which are directed azimuthally opposite to corotation with the planet and radially inwards, with magnitudes of similar to 100 km s(-1) in each component. Any variations in this flow during the outer magnetosphere traversal are not resolved within the similar to+/-100 km s(-1) uncertainties in the individual 35 min-averaged data. Similar flows, but of somewhat smaller magnitude, are also found in both data sets in the higher-latitude region of the inbound middle magnetosphere flanking the plasma sheet (similar to 45-70 R-J). It is inferred that these field lines map equatorially into the outer magnetosphere at larger distances. Flows within the middle magnetosphere plasma sheet in this region are on average in the sense of planetary rotation, but the average azimuthal velocity determined from the ATs data (similar to 20 km s(-1), essentially consistent with zero) is significantly smaller than that determined from the SWOOPS data (similar to 100 km s(-1)). A systematic effect thus seems to be present within the current sheet, possibly associated with additional (usually small) terms in the expression for the energetic ion anisotropy which have not been taken into account in the analysis procedure. Analysis of the inbound data overall, however, indicates no consistent velocity offset between these data sets to within a few tens of km s(-1), and a unit gradient between them within a factor of similar to 1.5. Due to the large uncertainties in individual similar to 35-min velocity values, however, and the possible current sheet effects mentioned above, the cross-correlation coefficient between the data sets is low, with an overall value of 0.23 for the principal azimuthal component observed in magnetospheric regions over a 4-day interval on the inbound pass. The probability of this degree of correlation appearing by chance, however, is only about one in 500. On the outbound pass, we find that the velocity estimates determined from the two data sets do not agree, even qualitatively. We believe that this is due to a complicated and anisotropic background in the electron data which we have been unable to fully remove. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Imperial Coll, Blackett Lab, London SW7 2BZ, England. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Cowley, SWH (reprint author), Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. EM swhcl@ion.le.ac.uk RI dunlop, malcolm/F-1347-2010 NR 31 TC 9 Z9 9 U1 0 U2 0 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 JAN-FEB PY 1999 VL 47 IS 1-2 BP 205 EP 224 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 179JT UT WOS:000079324100021 ER PT S AU Irwin, PGJ Taylor, FW Carlson, RW Baines, KH Weir, A Cameron-Smith, P Calcutt, S Encrenaz, T Drossart, P Roos-Serote, M Lellouch, E AF Irwin, PGJ Taylor, FW Carlson, RW Baines, KH Weir, A Cameron-Smith, P Calcutt, S Encrenaz, T Drossart, P Roos-Serote, M Lellouch, E BE Zasova, LV TI Jovian atmospheric studies with the Galileo near infrared mapping spectrometer: An update SO PLANETARY ATMOSPHERES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT c3 1 Symposium of COSPAR Scientific Commission C Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Ctr Natl Etudes Spatiales, European Space Agcy, Comm Space Res ID TROPOSPHERIC GAS-COMPOSITION; NORTH EQUATORIAL BELT; CLOUD STRUCTURE; IMAGING DATA; JUPITER; SPECTROPHOTOMETRY; METHANE; PROBE; D/H AB In its first two years of operation since arrival at Jupiter in December 1995, the Near Infrared Mapping spectrometer (NIMS) on the Galileo orbiter spacecraft obtained extensive coverage of the planet, including detailed coverage of the north equatorial belt (NEB) 'hot spot' region and the Great Red Spot. We will present the current state of data analysis including recent results on the abundances and variability of several minor constituents (H2O, CH4, NH3, GeH4, CH3D and PH3) and the cloud structure and morphology. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Oxford, Oxford OX1 3PU, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. Observ Paris, Dept Spatial, CNRS, URA 264, Meudon, France. RP Irwin, PGJ (reprint author), Univ Oxford, Parks Rd, Oxford OX1 3PU, England. RI Cameron-Smith, Philip/E-2468-2011; OI Cameron-Smith, Philip/0000-0002-8802-8627; Calcutt, Simon/0000-0002-0102-3170; Irwin, Patrick/0000-0002-6772-384X NR 22 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 9 BP 1623 EP 1632 DI 10.1016/S0273-1177(99)00179-9 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP13P UT WOS:000084217600011 ER PT J AU Davies, P Sims, GD Blackman, BRK Brunner, AJ Kageyama, K Hojo, M Tanaka, K Murri, G Rousseau, C Gieseke, B Martin, RH AF Davies, P Sims, GD Blackman, BRK Brunner, AJ Kageyama, K Hojo, M Tanaka, K Murri, G Rousseau, C Gieseke, B Martin, RH TI Comparison of test configurations for determination of mode II interlaminar fracture toughness results from international collaborative test programme SO PLASTICS RUBBER AND COMPOSITES LA English DT Article AB This paper presents a summary of the tests performed within a Versailles Project on Advanced Materials and Standards collaborative test programme to examine the measurement of mode II interlaminar fracture toughness using four different test methods based on end notched flexure, stabilised end notched flexure, end loaded split, and four point end notched flexure carbon fibre reinforced epoxy specimens. Tests were performed by members of the European Structural Integrity Society, the Japan Industrial Standards group, and the American Society for Testing and Materials. PRC/1546 (C) 1999 IoM Communications Ltd. C1 IFREMER, Ctr Brest, Technopole Brest Iroise, F-29280 Plouzane, France. Natl Phys Lab, Teddington, Middx, England. Univ London Imperial Coll Sci Technol & Med, London, England. Eidgenossische Mat Prufungs & Forschungsanhalt, Dubendorf, Switzerland. Univ Tokyo, Tokyo, Japan. Kyoto Univ, Kyoto, Japan. Toyama Prefectural Univ, Toyama, Japan. NASA, Hampton, VA USA. Bell Helicopters, Ft Worth, TX USA. Cincinnati Testing Labs, Cincinnati, OH USA. Mat Engn Res Lab Ltd, Hertford, England. RP IFREMER, Ctr Brest, Technopole Brest Iroise, BP 70, F-29280 Plouzane, France. RI davies, peter/C-6524-2011; OI davies, peter/0000-0002-0884-748X NR 15 TC 60 Z9 61 U1 2 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 1465-8011 EI 1743-2898 J9 PLAST RUBBER COMPOS JI Plast. Rubber Compos. PY 1999 VL 28 IS 9 BP 432 EP 437 PG 6 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 279TQ UT WOS:000085061600005 ER PT J AU Gloersen, P Huang, NE AF Gloersen, P Huang, NE TI In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978-1996 SO POLAR RESEARCH LA English DT Article; Proceedings Paper CT International Symposium on Polar Aspects of Global Change CY AUG 24-28, 1998 CL TROMSO, NORWAY SP Int Arctic Sci Comm, Sci Comm Antarctic Res, European Polar Board, Nordic Council Polar Res, Univ Tromso, Commiss Sci Res Greenland, Int Glaciol Soc, Arctic Monitoring & Assessment Programme, World Climate Res Programme, Arctic Climate Syst Study, Int Arctic Res Ctr AB For ease in discerning an Antarctic circumpolar wave in the perimeter of the ice pack, we construct a time series of the sea ice extents (essentially the area within the ice perimeter) in 1-degree longitudinal sectors for the period 1978-1996, as observed with the multichannel microwave imagers on board the NASA Nimbus 7 and the DOD (Dept. of Defense) DMSP (Defense Meteorological Satellite Program) F8, F11, and F13 satellites. After converting the time series into complex numbers by means of a Hilbert transform, we decompose the time series of the 360 sectors into its complex principal components (CPCs), effectively separating the spatial and temporal values. Then we decompose the real and imaginary parts of the temporal portions of the first three CPCs (complex principal compenents) by Empirical Mode Decomposition into their intrinsic modes, each representing a narrow frequency band, resulting in a collection of three CPCs for each intrinsic mode. Finally, we reconstruct the data in two different ways. First, we low-pass filter the data by combining all of the intrinsic modes of each CPC with periods longer than two years, which we designate as lowpass filtered. Next, we select the intrinsic mode of each CPC with periods of approximately four years, which we designate the quasiquadrennial (QQ) modes. The low-pass filtered time series shows eastward propagating azimuthal motion in the Ross and Weddell Seas, but no clearly circumpolar motion. The QQ time series, on the other hand, clearly shows eastward propagating circumpolar waves, but with occasional retrograde motion to the west. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Gloersen, P (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Code 661, Greenbelt, MD 20771 USA. NR 9 TC 8 Z9 8 U1 2 U2 2 PU NORWEGIAN POLAR INST PI OSLO PA MIDDELTHUNS GATE 29, POSTBOKS 5072 MAJORSTUA, 0301 OSLO, NORWAY SN 0800-0395 J9 POLAR RES JI Polar Res. PY 1999 VL 18 IS 2 BP 167 EP 173 DI 10.1111/j.1751-8369.1999.tb00289.x PG 7 WC Ecology; Geosciences, Multidisciplinary; Oceanography SC Environmental Sciences & Ecology; Geology; Oceanography GA 282PY UT WOS:000085228300010 ER PT J AU Muravyov, A AF Muravyov, A TI Determination of complex moduli of isotropic viscoelastic materials SO POLYMER TESTING LA English DT Article AB A procedure for determination of complex moduli of viscoelastic (polymeric) materials is described. The complex moduli of specimen's isotropic material are calculated from certain experimentally obtained data and with application of a 3-D finite element model of the experimental specimen. A system of two non-linear complex equations with respect to two complex Lame's moduli is formulated, and then solved by a successive approximation method. The convergence of the iterative procedure is observed for all cases. The complex moduli obtained for a series of polymeric materials are presented for 10-250 Hz frequency range. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ British Columbia, Dept Mech Engn, Vancouver, BC V6T 1W5, Canada. RP Muravyov, A (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 403,6 N Dryden St, Hampton, VA 23681 USA. EM muravyov@icase.edu NR 11 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-9418 J9 POLYM TEST JI Polym. Test PY 1999 VL 18 IS 4 BP 267 EP 279 DI 10.1016/S0142-9418(98)00025-7 PG 13 WC Materials Science, Characterization & Testing; Polymer Science SC Materials Science; Polymer Science GA 205AD UT WOS:000080798300005 ER PT B AU Queloz, D Casse, M Mayor, M AF Queloz, D Casse, M Mayor, M BE Hearnshaw, JB Scarfe, CD TI The fiber-fed spectrograph, a tool to detect planets SO PRECISE STELLAR RADIAL VELOCITIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 170 on Precise Stellar Radial Velocities CY JUN 21-26, 1998 CL VICTORIA, CANADA SP IAU Commiss 30 AB The use of fibers to feed spectrographs is a very efficient way to increase the precision of radial velocity measurements. It has already proved to be successful with the very first detection by the ELODIE fiber-fed spectrograph of the planet orbiting the star 51 Peg. The basic key properties of fibers in the very high radial velocity precision measurements context are described in this review. The ELODIE spectrograph is used to illustrate the thorium simultaneous calibration technique. The use and the effects of a double-scrambler to increase the stability of the slit illumination are also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Queloz, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 14 Z9 14 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-011-0 J9 ASTR SOC P PY 1999 VL 185 BP 13 EP 21 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP16N UT WOS:000084260500002 ER PT J AU Shiao, MC Chamis, CC AF Shiao, MC Chamis, CC TI Probabilistic evaluation of fuselage-type composite structures SO PROBABILISTIC ENGINEERING MECHANICS LA English DT Article AB A methodology is developed to simulate computationally the uncertain behavior of composite structures. The uncertain behavior includes buckling loads, natural frequencies, displacements, stress/strain, etc., which are the consequences of the random variation (scatter) of the primitive (independent random) variables in the constituent, ply, laminate and structural levels. This methodology is implemented in a computer code IPACS (integrated probabilistic assessment of composite structures). A fuselage-type composite structure is analyzed to demonstrate the code's capability. The probability distribution functions of the buckling loads, natural frequency, displacement, strain and stress are computed. The sensitivity of each primitive (independent random) variable to a given structural response is also identified from the analyses. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Sverdrup Technol Inc, Lewis Res Ctr Grp, Brookpark, OH USA. RP Chamis, CC (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 16 Z9 17 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-8920 J9 PROBABILIST ENG MECH JI Probab. Eng. Eng. Mech. PD JAN-APR PY 1999 VL 14 IS 1-2 BP 179 EP 187 DI 10.1016/S0266-8920(98)00027-7 PG 9 WC Engineering, Mechanical; Mechanics; Statistics & Probability SC Engineering; Mechanics; Mathematics GA 162KP UT WOS:000078345700019 ER PT B AU Gibbs, GP Eure, KW Lloyd, JW AF Gibbs, GP Eure, KW Lloyd, JW BE Douglas, S TI Active control of turbulent boundary layer induced sound radiation from aircraft style panels SO PROCEEDINGS OF ACTIVE 99: THE INTERNATIONAL SYMPOSIUM ON ACTIVE CONTROL OF SOUND AND VIBRATION, VOLS 1 & 2 LA English DT Proceedings Paper CT 1999 International Symposium on Active Control of Sound and Vibration (ACTIVE 99) CY DEC 02-04, 1999 CL FT LAUDERDALE, FL SP Inst Noise Control Engn USA ID MODES C1 NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. RP Gibbs, GP (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. NR 13 TC 2 Z9 2 U1 0 U2 1 PU INST NOISE CONTROL ENGINEERING PI POUGHKEEPSIE PA PO BOX 3206, ARLINGTON BRANCH, POUGHKEEPSIE, NY 12603 USA BN 0-9622072-2-5 PY 1999 BP 837 EP 848 PG 4 WC Acoustics SC Acoustics GA BQ99G UT WOS:000165304400072 ER PT B AU Hoffman, AR Forgrave, JC AF Hoffman, AR Forgrave, JC GP IEST IEST TI Cassini environmental test and analysis program summary SO PROCEEDINGS OF THE 18TH AEROSPACE TESTING SEMINAR LA English DT Proceedings Paper CT 18th Aerospace Testing Seminar CY MAR 16-18, 1999 CL MANHATTAN BEACH, CA SP Inst Environm Sci & Technol, Aerosp Corp DE acoustics; Cassini; environmental test; electromagnetic compatibility; natural space environment; pyro-shock; radiation; single event effects; solar thermal vacuum; vibration AB This paper presents an overview of the Cassini Project's environmental test and analysis program during the spacecraft development phase - October 1989 to launch in October 1997. It describes the program's objectives and requirements, and then summarizes the approach used to achieve them, and provides the margins that were achieved in the final design. Assembly and system level environmental tests that were performed included dynamic, thermal, electromagnetic compatibility (EMC), and magnetic tests. Analysis was used to verify that the environmental requirements of radiation, solid particles including micrometeoroids, and single event effects have been satisfied. The environmental program implemented on Cassini satisfied the spirit and intent of the requirements imposed by the Project during the spacecraft's development. The lessons learned from the Cassini environmental program are discussed in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hoffman, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 USA BN 1-877862-56-8 PY 1999 BP 99 EP 123 PG 3 WC Engineering, Aerospace SC Engineering GA BQ54M UT WOS:000088718700009 ER PT B AU Ottens, BP AF Ottens, BP GP IEST IEST TI Design/use of the Remotely Operated Bakeout Box Shutter (ROBBS) SO PROCEEDINGS OF THE 18TH AEROSPACE TESTING SEMINAR LA English DT Proceedings Paper CT 18th Aerospace Testing Seminar CY MAR 16-18, 1999 CL MANHATTAN BEACH, CA SP Inst Environm Sci & Technol, Aerosp Corp DE space simulation; box bakeout; thermal vacuum; test engineering; contamination engineering; robotics; NASA Goddard Space Flight Center; facilities engineering; mechanical engineering design AB A thermal vacuum box bakeout and certification allows orbital payloads to be cleaned and certified when the background TQCM measurements (a measure of how much molecular contamination is on a payload or chamber) are unacceptable or unmanageable in the standard thermal vacuum chamber. The box bakeout procedure is usually performed in 4 steps: bakeout the box, certify the box, bake out the payload, and finally certify the payload. In the procedure's current setup, the contaminant conduction hole ("lid") is initially open and a vacuum chamber break must occur between the bakeout and certification phases to close the box from the vacuum chamber. This exposure is necessary to allow the outgassed contaminants to escape the box's volume rapidly during bakeout phase, but payload certification isn't usually performed while the lid is still open, because it exposes the payload, TQCM, and box volume to chamber contaminants. The Remotely Operated Bakeout Box Shutter (ROBBS) is a new facility design and will allow the remote closure of the contamination hole while the chamber is still under vacuum, and with little or no time to do so. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ottens, BP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 USA BN 1-877862-56-8 PY 1999 BP 371 EP 392 PG 12 WC Engineering, Aerospace SC Engineering GA BQ54M UT WOS:000088718700030 ER PT B AU Scharton, T Vujcich, M AF Scharton, T Vujcich, M GP IEST IEST TI Combined loads, vibration, and modal testing of the QuikSCAT spacecraft SO PROCEEDINGS OF THE 18TH AEROSPACE TESTING SEMINAR LA English DT Proceedings Paper CT 18th Aerospace Testing Seminar CY MAR 16-18, 1999 CL MANHATTAN BEACH, CA SP Inst Environm Sci & Technol, Aerosp Corp DE vibration testing; force; QuikSCAT AB Combining the quasi-static loads, workmanship verification, and model validation tests of aerospace hardware into a single vibration test sequence can considerably reduce schedule and cost. The enabling factor in the implementation of the combined dynamic testing approach is the measurement of the dynamic forces exerted on the test item by the shaker. The dynamic testing of the QuikSCAT spacecraft is discussed as an example of a successful combined loads, workmanship, and model validation test program. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scharton, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 USA BN 1-877862-56-8 PY 1999 BP 419 EP 428 PG 4 WC Engineering, Aerospace SC Engineering GA BQ54M UT WOS:000088718700034 ER PT S AU Northcutt, RT Byrd, T AF Northcutt, RT Byrd, T BE Derksen, CRM Manson, CJ TI NASA's global change master directory (GCMD): A multidisciplinary approach to locating earth science data SO PROCEEDINGS OF THE 33RD MEETING OF THE GEOSCIENCE INFORMATION SOCIETY: ACCRETING THE CONTINENT'S COLLECTIONS SE PROCEEDINGS OF THE GEOSCIENCE INFORMATION SOCIETY LA English DT Meeting Abstract CT 33rd Meeting of the Geoscience-Information-Society CY OCT 25-28, 1998 CL TORONTO, CANADA SP Geosci Informat Soc C1 NASA, Global Change Master Directory, Greenbelt, MD 20770 USA. RP Northcutt, RT (reprint author), NASA, Global Change Master Directory, RSTX,7701 Greenbelt Rd, Greenbelt, MD 20770 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU GEOSCIENCE INFORMATION SOC PI ALEXANDRIA PA AMERICAN GEOLOGICAL INSTITUTE, 4220 KING ST, ALEXANDRIA, VA 22302 USA SN 0072-1409 BN 0-934485-31-3 J9 P GEOS INF PY 1999 VL 29 BP 85 EP 85 PG 1 WC Geosciences, Multidisciplinary SC Geology GA BP21M UT WOS:000084418400013 ER PT B AU Bagheri, M AF Bagheri, M BE Newaz, GM Gibson, RF TI The three-point bending test, a critical review SO PROCEEDINGS OF THE EIGHTH JAPAN-U.S. CONFERENCE ON COMPOSITE MATERIALS LA English DT Proceedings Paper CT 8th Japan-US Conference on Composite Materials CY SEP 24-25, 1998 CL BALTIMORE, MD SP Wayne St Univ, Amer Soc Composites, Japan Soc Composite Mat AB The interlaminar shear strength of composite materials is often determined by the short-beam shear test method. However, the short-beam shear test method does not always produce pure shear failures. To insure a pure state of shear, a span-to-depth ratio must be chosen such that non-shear or mixed-mode failures can be avoided. To obtain a proper span-to-depth ratio, elementary beam theory was used in associations with experimental results obtained for composite materials. Also, since instantaneous stress changes are physically impossible, as predicted by simple beam theory, it is suggested that the overhang could effect the maximum shear strength for composite materials. These topics are the subject of the present paper. The results of this experimental study show that a clear understanding of the failure modes is a must to avoid erroneous results. Also, the span-to-depth ratio must be obtained experimentally to insure the pure shear mode of failure. C1 N Carolina Agr & Technol State Univ, Coll Engn, CAR, NASA, Greensboro, NC 27411 USA. RP Bagheri, M (reprint author), N Carolina Agr & Technol State Univ, Coll Engn, CAR, NASA, Greensboro, NC 27411 USA. NR 15 TC 0 Z9 0 U1 1 U2 2 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-718-0 PY 1999 BP 683 EP 692 PG 10 WC Materials Science, Composites SC Materials Science GA BP30Z UT WOS:000084658600070 ER PT B AU McKay, CP AF McKay, CP BE Zubrin, RM Zubrin, M TI Mars: The case for life SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT I LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-12-8 PY 1999 BP 17 EP 23 PG 7 WC Engineering, Aerospace SC Engineering GA BN78J UT WOS:000082928900002 ER PT B AU Scott, DM AF Scott, DM BE Zubrin, RM Zubrin, M TI Preparing for the journey: An introduction to Mars education SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT I LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen AB This paper is about Mars educational resources, both of the nuts-and-bolts type, and of the higher country of the mind. During the past 25 years, much work has been done to prepare humankind for Mars. In technical, scientific, and economic terms, we are pretty well prepared to go, to explore, and to return. But a major Mars preparation task needs more attention. This is the education of the "Mars Kids"; the children now in school, who will design, fund, and conduct the human missions to Mars. Those first Martians currently attend school here on Earth. A good education will be the foundation for their successful missions to Mars. This is even more true if we seek to develop the most efficient and cost-effective human missions. Teachers who are teaching the Mars Generation need resources to help them with the job. One such resource is the set of nuts-and-bolts materials available to teachers who would prepare the Mars Kids. Another is a new way of thinking, along the lines described by NASA's Jesco von Puttkamer: "... a new frame of mind that shifts the emphasis from individual subjects to the interactions and relationships between them." C1 Oklahoma State Univ, NASA, Ames Res Ctr, Stillwater, OK 74078 USA. RP Scott, DM (reprint author), Oklahoma State Univ, NASA, Ames Res Ctr, Stillwater, OK 74078 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-12-8 PY 1999 BP 243 EP 252 PG 10 WC Engineering, Aerospace SC Engineering GA BN78J UT WOS:000082928900027 ER PT B AU Dorais, GA Bonasso, RP Kortenkamp, D Pell, B Schreckenghost, D AF Dorais, GA Bonasso, RP Kortenkamp, D Pell, B Schreckenghost, D BE Zubrin, RM Zubrin, M TI Adjustable autonomy for human-centered autonomous systems on Mars SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT II LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen AB We expect a variety of autonomous systems, from revers to life-support systems, to play a critical role in the success of manned Mars missions. The crew and ground support personnel will want to control and be informed by these systems at varying levels of detail depending on the situation. Moreover, these systems will need to operate safely in the presence of people and cooperate with them effectively. We call such autonomous systems human-centered in contrast with traditional "black-box" autonomous systems. Our goal is to design a framework for human-centered autonomous systems that enables users to interact with these systems at whatever level of control is most appropriate whenever they so choose, but minimize the necessity for such interaction. This paper discusses on-going research at the NASA Ames Research Center and the Johnson Space Center in developing human-centered autonomous systems that can be used for a manned Mars mission. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Dorais, GA (reprint author), NASA, Ames Res Ctr, Mail Stop 269-2, Moffett Field, CA 94035 USA. EM gadarais@ptolemy.arc.nasa.gov; bonasso@mickey.jsc.nasa.gov; kortenkamp@jsc.nasa.gov; pell@ptolemy.arc.nasa.gov; schreck@mickey.jsc.nasa.gov NR 20 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-13-6 PY 1999 BP 397 EP 419 PG 23 WC Engineering, Aerospace SC Engineering GA BN78K UT WOS:000082929000002 ER PT B AU Gibson, EK McKay, DS Thomas-Keprta, K AF Gibson, EK McKay, DS Thomas-Keprta, K BE Zubrin, RM Zubrin, M TI Life on Mars: Evidence within Martian meteorites SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT II LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen ID LOW-TEMPERATURE; EPITAXIAL-GROWTH; PAST LIFE; ALH84001; ALLAN-HILLS-84001; CARBONATES; SHERGOTTITES; MAGNETITE; ORIGIN; MINERALIZATION C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Gibson, EK (reprint author), NASA, Johnson Space Ctr, Houston, TX 77058 USA. NR 47 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-13-6 PY 1999 BP 437 EP 447 PG 11 WC Engineering, Aerospace SC Engineering GA BN78K UT WOS:000082929000004 ER PT B AU Pauly, K AF Pauly, K BE Zubrin, RM Zubrin, M TI A comparison of in situ resource utilization options for the first human Mars missions SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT II LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen AB The current plans of NASA for the first missions to Mars involve in situ resource utilization (ISRU). Goal of the six month study carried out at the Johnson Space Center (Ref. 1) was to obtain an independent assessment about whether ISRU can provide the advantages in mass and cost that are claimed by the approvers. Furthermore it was tried to obtain a non-biased comparison of the different ISRU options proposed for a human Mars mission in order to find the optimum option for such a mission. The study is based as far as possible on actually built production units and less on previous theoretical studies. It is shown that estimations of the approvers of ISRU are very often too optimistic and that many options, which look good at first sight, have to be ruled out due to practical reasons during detailed review. Nevertheless, some options remain very promising and actually have the potential of decreasing mass and cost of such a mission. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Pauly, K (reprint author), Tech Univ Munich, Div Astronaut, D-85747 Garching, Germany. NR 12 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-13-6 PY 1999 BP 681 EP 694 PG 14 WC Engineering, Aerospace SC Engineering GA BN78K UT WOS:000082929000021 ER PT B AU Peek, KE AF Peek, KE BE Zubrin, RM Zubrin, M TI Mars mission operations SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT II LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Peek, KE (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-13-6 PY 1999 BP 723 EP 728 PG 6 WC Engineering, Aerospace SC Engineering GA BN78K UT WOS:000082929000026 ER PT B AU Landis, GA AF Landis, GA BE Zubrin, RM Zubrin, M TI Polar landing site for a first Mars expedition SO PROCEEDINGS OF THE FOUNDING CONVENTION OF THE MARS SOCIETY, PT III LA English DT Proceedings Paper CT Founding Convention of the Mars-Society CY AUG 13-16, 1998 CL BOULDER, CO SP Mars Soc, Natl Geograph Soc, Longview Fdn, Bushnell Corp, Fisher Space Pen AB A first Mars expedition will be greatly facilitated by use of in-situ Mars resources for producing return propellant. While most discussions of Mars resource availability assume that a Mars mission will target an equatorial or mid-latitude site, I argue here that there are significant advantages to choosing the polar regions for an initial landing site. Polar regions facilitate easy access to Mars volatiles in the form of frozen water and carbon dioxide. This is important not only for production of rocket fuel for the return to Earth, but for production of fuel for local mobility. A polar expedition would not have to bring hydrogen from Earth to produce propellant, but could extract hydrogen by simply melting available ice. Also, during the Mars summer, the Sun is constantly above the horizon. This allows continuous power generation without the requirement for heavy power storage systems, and allows direct communications to Earth. While a polar site may be less desirable for some geological studies, since the terrain is ice-covered, geological studies of non-ice-covered terrain can easily be accomplished by use of a long-range rover, and there are unique exploration possibilities to gather information available from polar science which is not found elsewhere on the planet. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mail Stop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA BN 0-912183-14-4 PY 1999 BP 835 EP 842 PG 8 WC Engineering, Aerospace SC Engineering GA BN78L UT WOS:000082929100011 ER PT B AU Lou, JZ Norton, CD Cwik, TA AF Lou, JZ Norton, CD Cwik, TA BE Tentner, A TI PYRAMID: A parallel adaptive mesh refinement software library for unstructured computations SO PROCEEDINGS OF THE HIGH PERFORMANCE COMPUTING SYMPOSIUM - HPC '99 LA English DT Proceedings Paper CT 1999 Advanced Simulation Technologies Conference (ASTC 99) CY APR 11-15, 1999 CL SAN DIEGO, CA SP Soc Comp Simulat Int AB The design and implementation of Pyramid (http://www-hpc.jpl.nasa.gov/APPS/AMR/), a software library for performing parallel adaptive mesh refinement (PAMR) on unstructured meshes, is described. This software library can be easily used in a variety of unstructured parallel computational applications, including parallel finite element, parallel finite volume, and parallel visualization applications using triangular or tetrahedral meshes. The library contains a suite of well-designed and efficiently implemented modules that perform operations in a typical parallel AMR process. Among these are mesh quality control during successive parallel adaptive refinement (typically guided by a local-error estimator), parallel load-balancing, and parallel mesh partitioning using the ParMeTiS partitioner. The Pyramid library is implemented in Fortran 90 with an interface to the Message-Passing Interface (MPI) library, supporting code efficiency, modularity, and portability. An EM waveguide filter application, adaptively refined using the Pyramid library, is illustrated, and an initial performance study on the Gray T3E system is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lou, JZ (reprint author), CALTECH, Jet Prop Lab, MS 168-522,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 1 U2 1 PU SOC COMPUTER SIMULATION PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92177 USA BN 1-56555-166-4 PY 1999 BP 132 EP 137 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods; Engineering, Multidisciplinary SC Computer Science; Engineering GA BN24B UT WOS:000081234800023 ER PT S AU Dischinger, HC Tilghman, NC Hammons, M Hale, JP AF Dischinger, HC Tilghman, NC Hammons, M Hale, JP GP HFES HFES TI DUET: A distributed usability lab supporting displays development for Space Station SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 43RD ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 43rd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY SEP 27-OCT 01, 1999 CL HOUSTON, TX SP Human Factors & Ergon Soc AB A usability laboratory recently established at NASA's Marshall Space Flight Center will support the development of interfaces to on-board Payload displays on the International Space Station. An unusual feature of this facility is its ability to conduct usability testing over the Internet. Test subjects interact with the remote application displays using the remote-view and -control package Timbuktu Pro. Both test subject and developer facility are typically remote to the lab; the only site requirements are appropriate viewing hardware and software and an Internet drop. The lab, called the Distributed Usability Evaluation Tool (DUET), utilizes off-the-shelf hardware and software. Included are Space Station-type laptops (IBM Thinkpad 760 XD), Windows 95 OS, a usability data-collection package (WinWhatWhere), and Timbuktu Pro. Data on test subject commentary and reaction are collected through videoconferencing when available, and through teleconferencing otherwise. Developers gain access to the test facility through instructions and software obtained from the lab's web site. DUET also serves as a display development support tool. The web site includes usability guidelines and templates. Moreover the staff consult on usability and standards compliance via telephone and net communication. Prototypes are evaluated using an electronic whiteboard. This tool is connected to the developer's displays via the same networking approach as is used for the test: the developer connects to the lab through Timbuktu Pro, the prototypes are displayed on the whiteboard, and comments and modifications are made collaboratively by the developer and the lab staff. Examples of support and test successes and issues will be presented. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Dischinger, HC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-12-X J9 HUM FAC ERG SOC P PY 1999 BP 1095 EP 1098 PG 4 WC Computer Science, Cybernetics; Ergonomics; Telecommunications; Transportation Science & Technology SC Computer Science; Engineering; Telecommunications; Transportation GA BS93U UT WOS:000171438400210 ER PT S AU Ellis, SR Young, MJ Adelstein, BD Ehrlich, SM AF Ellis, SR Young, MJ Adelstein, BD Ehrlich, SM GP HFES HFES TI Discrimination of changes of latency during voluntary hand movement of virtual objects SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 43RD ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 43rd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY SEP 27-OCT 01, 1999 CL HOUSTON, TX SP Human Factors & Ergon Soc ID VISUAL FEEDBACK AB Eight subjects' abilities to detect changes in system latency during voluntary lateral hand movement of virtual objects were studied in an immersing virtual environment. A two-alternative forced choice procedure was used in which discrimination of latency was studied with respect to three reference latencies: 27, 94, and 194 msec. Results show that subjects are able to reliably detect changes definitely less than 33 msec and probably less than 16.7 msec. Strikingly, for the short latencies we examined, subjects' ability to detect latency changes does not depend upon the base latency we used as a reference. Thus, the discrimination we studied does not appear to follow Weber's law and may provide evidence for quick adaptation to the reference latencies used. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 14 Z9 14 U1 0 U2 1 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-12-X J9 HUM FAC ERG SOC P PY 1999 BP 1182 EP 1186 PG 5 WC Computer Science, Cybernetics; Ergonomics; Telecommunications; Transportation Science & Technology SC Computer Science; Engineering; Telecommunications; Transportation GA BS93U UT WOS:000171438400226 ER PT S AU McCandless, JW Ellis, SR Adelstein, BD AF McCandless, JW Ellis, SR Adelstein, BD GP HFES HFES TI The effect of accommodative demand, motion parallax and age on virtual object localizations SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 43RD ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 43rd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY SEP 27-OCT 01, 1999 CL HOUSTON, TX SP Human Factors & Ergon Soc ID DEPTH-PERCEPTION; ABSOLUTE-DISTANCE; VISUAL-FIELD; ENVIRONMENTS; STEREOPSIS; ACCURACY AB Observers adjusted the position of a physical pointer to localize a computer-generated, space-stabilized, virtual object presented monocularly in a see-through, head-mounted display. Each observer rocked side to side to produce motion parallax to determine the depicted distance of the object. The depicted distance (75 and 113 cm) of the virtual object was specified by motion parallax and accommodative demand. Six younger (18-20 years) and six older (40-70 years) observers participated in the study. Both motion parallax and accommodative demand were independent, significant factors driving the localization of virtual objects. Motion parallax was markedly more influential than accommodative demand. Object localization was not affected significantly by the observers' ages, possibly due to the small change in accommodative demand and the relative strength of motion parallax. C1 NASA, Ames Res Ctr, Human Informat Proc Res Branch, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Human Informat Proc Res Branch, Moffett Field, CA 94035 USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-12-X J9 HUM FAC ERG SOC P PY 1999 BP 1328 EP 1332 PG 5 WC Computer Science, Cybernetics; Ergonomics; Telecommunications; Transportation Science & Technology SC Computer Science; Engineering; Telecommunications; Transportation GA BS93U UT WOS:000171438400256 ER PT B AU Morris, RD Cheeseman, P Smelyanskiy, VN Maluf, DA AF Morris, RD Cheeseman, P Smelyanskiy, VN Maluf, DA GP IEEE COMP SOC IEEE COMP SOC TI A Bayesian approach to high resolution 3D surface reconstruction from multiple images SO PROCEEDINGS OF THE IEEE SIGNAL PROCESSING WORKSHOP ON HIGHER-ORDER STATISTICS LA English DT Proceedings Paper CT IEEE Signal Processing Workshop on Higher-Order Statistics CY JUN 14-16, 1999 CL CAESAREA, ISRAEL SP IEEE Comp Soc, IEEE Israel Sect, Tel Aviv Univ, Technion, Ben-Gurion Univ, Negev Fac Engn Sci AB We present a radically different approach to the recovery of the three dimensional geometric and reflectance properties of a surface from image data. We pose the problem in a Bayesian framework, and proceed to infer the parameters of the model describing the surface. This allows great flexibility in the specification of the model, in terms of how both the geometrical properties and surface reflectance are specified. In the usual manner for Bayesian approaches it requires that we can simulate the data that would have been recorded for any state of the model in order to infer the model. The theoretical aspects are thus very general. We present results for one type of surface geometry (the triangular mesh) and far the Lambertian model of light scattering. Our framework also allows the easy incorporation of data from multiple sensing modalities. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Morris, RD (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0141-9 PY 1999 BP 140 EP 143 DI 10.1109/HOST.1999.778711 PG 2 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Statistics & Probability; Telecommunications SC Computer Science; Engineering; Mathematics; Telecommunications GA BN38Q UT WOS:000081763600031 ER PT B AU Chen, DW Wu, HI Dischinger, C AF Chen, DW Wu, HI Dischinger, C BE Ades, M TI Evaluating and implementing human performance modeling packages for human factors analysis SO PROCEEDINGS OF THE INDUSTRIAL & BUSINESS SIMULATION SYMPOSIUM LA English DT Proceedings Paper CT 1999 Advanced Simulation Technologies Conference (ASTC 99) CY APR 11-15, 1999 CL SAN DIEGO, CA SP Soc Comp Simulat Int DE virtual reality; micro-gravity; articulation; human figures and activities AB Human factors modeling has been in use by NASA to assure mission success via increasing the safety of astronauts and reducing the design costs of International Space Station (ISS) and extravehicular activities (EVA, spacewalks). In this study, two human factors modeling packages: Jack (v 1.2) and ERGO (v 4.0) were compared according to their superiority, usability, and applicability. Both packages were also used to simulate the ISS Patch System experimental design. Through this study, we found that the modeling is an effective tool in a comprehensive human factors investigation of activities. At present, most human factors modeling packages are still at a developing stage for simulating more realistically and accurately human figures and activities in normal and micro-gravity virtual reality environments. C1 Clark Atlanta Univ, Atlanta, GA 30314 USA. Texas A&M Univ, College Stn, TX 77843 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Chen, DW (reprint author), Clark Atlanta Univ, Atlanta, GA 30314 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SOC COMPUTER SIMULATION PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92177 USA BN 1-56555-167-2 PY 1999 BP 27 EP 32 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Industrial SC Computer Science; Engineering GA BN23Z UT WOS:000081232100006 ER PT S AU Liu, AK Wu, SY Leonard, GH Hsu, MK AF Liu, AK Wu, SY Leonard, GH Hsu, MK BE Chung, JS Matsui, T Koterayama, W TI Applications of satellite data for coast monitoring SO PROCEEDINGS OF THE NINTH (1999) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 1, 1999 SE International Offshore and Polar Engineering Conference Proceedings LA English DT Proceedings Paper CT 9th International Offshore and Polar Engineering Conference (ISOPE-99) CY MAY 30-JUN 04, 1999 CL BREST, FRANCE SP Int Soc Offshore & Polar Engineers, Canadian Assoc Petr Producers, Amer Soc Civil Engineers, Engn Mech Div, Korea Comm Ocean Resources & Engn, Canadian Civil Engineers, Engn Mech Div, Chinese Soc Ocean Engineers, Chinese Soc Naval Architects & Marine Engineers, Chinese Soc Theoret & Applied Mech, Russian Acad Sci, Singapore Struct Steel Soc, Norwegian Petr Soc, Inst Engineers Australia, Kansai Soc Naval Architects, Japan, IRO, Netherlands, Tech Res Ctr Finland, Soc Mat Sci, Japan, Offshore Engn Soc, UK, Ukraine Soc Mech Engineers, IFREMER, France, Scott Polar Res Inst, UK, Inst Engineers Indonesia, Brazilian Soc Naval Architects & Marine Engineers DE coast monitoring; marine pollution; remote sensing; ship wake; SAR ID APERTURE RADAR IMAGERY; WAVELET ANALYSIS AB The mapping of mesoscale ocean features in the coastal zone is a major potential application for satellite data. Synthetic Aperture Radar (SAR) is not affected by clouds and can provide images with better spatial coverage than field measurements. The evolution of mesoscale features such as oil slicks, fronts, eddies, and ice flees can be tracked using satellite data from repeating paths. In this paper, case studies of wind pattern in channel, coastal pollution, and ship wakes along coast are presented for demonstration purpose. Examples of marine pollution in the coast of Taiwan observed from satellite SAR images are studied. Some interesting ship wakes are presented to classify various operation and processes involved. In addition, an overview of the SAR related projects for ocean applications will be discussed as well as the use of multi-sensors for operational coast monitoring. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Liu, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Leonard, Greg/F-7157-2010 NR 11 TC 0 Z9 0 U1 1 U2 1 PU INTERNATIONAL SOCIETY OFFSHORE& POLAR ENGINEERS PI CUPERTINO PA PO BOX 189, CUPERTINO, CA 95015-0189 USA SN 1098-6189 BN 1-880653-40-0 J9 INT OFFSHORE POLAR E PY 1999 BP 434 EP 440 PG 7 WC Engineering, Marine; Engineering, Geological; Remote Sensing SC Engineering; Remote Sensing GA BN17V UT WOS:000080987600065 ER PT B AU Narayanan, SR Valdez, TI Rohatgi, N Christiansen, J Chun, W Halpert, G AF Narayanan, SR Valdez, TI Rohatgi, N Christiansen, J Chun, W Halpert, G BE Gottesfeld, S Fuller, TF TI Electrochemical factors in design of direct methanol fuel cell systems SO PROCEEDINGS OF THE SECOND INTERNATIONAL SYMPOSIUM ON PROTON CONDUCTING MEMBRANE FUEL CELL II SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 2nd International Symposium on Proton Conducting Membrane Fuel Cells CY NOV 01-05, 1998 CL BOSTON, MA SP Electrochem Soc, Energy Technol Phys Electrochem, Electrochem Soc, Battery Div AB The design of direct methanol fuel cell based portable power source is being pursued at JPL. Performance data obtained on Nafion-based fuel cells have been used to develop a closed loop system model. The model has been exercised to obtain information on the impact of the various possible operating conditions on size, mass and efficiency of portable systems. Flow rate of air, methanol concentration and temperature are found to key controllable variables that significantly impact system size and efficiency. The results of the modeling studies are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Narayanan, SR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-221-4 J9 ELEC SOC S PY 1999 VL 98 IS 27 BP 316 EP 326 PG 11 WC Electrochemistry SC Electrochemistry GA BM63K UT WOS:000079309600031 ER PT B AU Valdez, TI Narayanan, SR AF Valdez, TI Narayanan, SR BE Gottesfeld, S Fuller, TF TI Recent studies on methanol crossover in liquid-feed direct methanol fuel cells SO PROCEEDINGS OF THE SECOND INTERNATIONAL SYMPOSIUM ON PROTON CONDUCTING MEMBRANE FUEL CELL II SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 2nd International Symposium on Proton Conducting Membrane Fuel Cells CY NOV 01-05, 1998 CL BOSTON, MA SP Electrochem Soc, Energy Technol Phys Electrochem, Electrochem Soc, Battery Div ID MEMBRANES AB In this work, the effects of methanol crossover and airflow rates on the cathode potential of an operating direct methanol fuel cell are explored Techniques for quantifying methanol crossover in a fuel cell and for separating the electrical performance of each electrode in a fuel cell are discussed. The Effect of methanol concentration on cathode potential has been determined to be significant. The cathode is found to be mass transfer limited when operating on low airflow rate and high concentrations of methanol Improvements in cathode structure and low methanol concentrations have been shown to result in improved cell performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Valdez, TI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 1 U2 2 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-221-4 J9 ELEC SOC S PY 1999 VL 98 IS 27 BP 380 EP 387 PG 8 WC Electrochemistry SC Electrochemistry GA BM63K UT WOS:000079309600036 ER PT B AU Stoica, A AF Stoica, A GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Toward evolvable hardware chips: Experiments with a programmable transistor array SO PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON MICROELECTRONICS FOR NEURAL, FUZZY AND BIO-INSPIRED SYSTEMS, MICORNEURO'99 LA English DT Proceedings Paper CT 7th International Conference on Microelectronics for Neural, Fuzzy and Bio-inspired Systems CY APR 07-09, 1999 CL GRANADA, SPAIN SP Univ Granada, Dept Architecture & Technol Comp, Spanish RIG, IEEE Neural Network Council, Univ Granada, Minist Educ Cultura, Consejeria Univ, CICYT AB Evolvable Hardware is reconfigurable hardware that self-configures larder the control of an Evolutionary algorithm. The search for a hardware configuration can be performed using software models or, faster and more accurate, directly in reconfigurable hardware. Several experiments have demonstrated the possibility to automatically synthesize both digital and analog circuits. The paper introduces an approach to automated synthesis of CMOS circuits, based on evolution on a Programable Transistor Array (PTA). The approach is illustrated with a software experiment showing evolutionary synthesis of a circuit with a desired DC characteristic. A hardware implementation of-a test PTA chip is then described, and the same evolutionary experiment is performed on the chip demonstrating circuit sythesis/self-configuration directly in hardware. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Stoica, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 8 TC 14 Z9 15 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0043-9 PY 1999 BP 156 EP 162 DI 10.1109/MN.1999.758859 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BM86N UT WOS:000079963400021 ER PT B AU Gunapala, SD Bandara, SV Liu, JK Luong, EM McKelvey, MJ Mumolo, JM Shott, CA Stetson, N Rafol, SD AF Gunapala, SD Bandara, SV Liu, JK Luong, EM McKelvey, MJ Mumolo, JM Shott, CA Stetson, N Rafol, SD BE Li, SS Liu, HC Tidrow, MZ Gunapala, SD TI Long-wavelength 256x256 GaAs/AlGaAs quantum well infrared photodetector (QWIP) palm-size camera SO PROCEEDINGS OF THE SIXTH INTERNATIONAL SYMPOSIUM ON LONG WAVELENGTH INFRARED DETECTORS AND ARRAYS: PHYSICS AND APPLICATIONS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 6th International Symposium on Long Wavelength Infrared Detectors and Arrays - Physics and Applications, at the Fall Meeting of the Electrochemical-Society CY NOV 05-06, 1998 CL BOSTON, MA SP Electrochem Soc DE intersubband transition; infrared (IR); long-wavelength infrared (LWIR); focal plane arrays (FPAs); gallium arsenide (GaAs); quantum well infrared photodetectors (QWIPs); noise equivalent temperature difference (NE Delta T); infrared imaging cameras AB A 9 mu m cutoff 256x256 palm-size quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 23 mK has been achieved. In this paper, we discuss the development of this very sensitive long-wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in terms of quantum efficiency, NE Delta T, uniformity, and operability. C1 CALTECH, Jet Propuls Lab, Ctr Space Microelect Technol, Pasadena, CA 91125 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Propuls Lab, Ctr Space Microelect Technol, Pasadena, CA 91125 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-215-X J9 ELEC SOC S PY 1999 VL 98 IS 21 BP 83 EP 94 PG 12 WC Electrochemistry; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Applied SC Electrochemistry; Engineering; Instruments & Instrumentation; Physics GA BM81T UT WOS:000079832100006 ER PT B AU Bandara, SV Gunapala, SD Wilson, DW Liu, JK Luong, EM Mumolo, JM Tran, NQ Hong, W McKelvey, MJ AF Bandara, SV Gunapala, SD Wilson, DW Liu, JK Luong, EM Mumolo, JM Tran, NQ Hong, W McKelvey, MJ BE Li, SS Liu, HC Tidrow, MZ Gunapala, SD TI Spectral band tuning and light coupling of Quantum Well Infrared Photodetectors SO PROCEEDINGS OF THE SIXTH INTERNATIONAL SYMPOSIUM ON LONG WAVELENGTH INFRARED DETECTORS AND ARRAYS: PHYSICS AND APPLICATIONS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 6th International Symposium on Long Wavelength Infrared Detectors and Arrays - Physics and Applications, at the Fall Meeting of the Electrochemical-Society CY NOV 05-06, 1998 CL BOSTON, MA SP Electrochem Soc ID PHOTOCONDUCTIVE GAIN; NOISE; DETECTORS; CAMERA AB Quantum Well Infrared Photodetectors (QWIPs) afford greater flexibility than the usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored by varying layer thickness (welt width) barrier composition (barrier height), and carrier density (well doping density). The GaAs/AlXGa1-XAs material system allows the quantum well parameters to be varied over a range wide enough to enable light detection at any wavelength range between 6-20 mu m. The spectral band width of these detectors can be tuned from narrow (Delta lambda/lambda similar to 10 %) to wide (Delta lambda/lambda similar to 40 %) allowing various applications. A new light coupling approach for QWIPs consists of a standard mesa and grating with slots of QWIP material removed is discussed. The removal of QWIP material reduces dark current. The modeling effort revealed structural parameters that yield strong optical coupling, which is less sensitive for wavelength. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Bandara, SV (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-215-X J9 ELEC SOC S PY 1999 VL 98 IS 21 BP 113 EP 121 PG 9 WC Electrochemistry; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Applied SC Electrochemistry; Engineering; Instruments & Instrumentation; Physics GA BM81T UT WOS:000079832100009 ER PT J AU Lockwood, MK Petley, DH Martin, JG Hunt, JL AF Lockwood, MK Petley, DH Martin, JG Hunt, JL TI Airbreathing hypersonic vehicle design and analysis methods and interactions SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review AB The design and analysis of airbreathing hypersonic vehicles is discussed. Individual discipline methods as well as the extensive interactions among the disciplines are described. Examples of the use of HOLIST, a framework currently in development to modularly integrate the analysis methods for use in design and optimization, are given along with plans for further development. (C) 1999. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Syst Anal Off, Hyper X Program Off, Adv Transportat Technol Off,Langley Res Ctr, Hampton, VA 23681 USA. RP Lockwood, MK (reprint author), NASA, Syst Anal Off, Hyper X Program Off, Adv Transportat Technol Off,Langley Res Ctr, Hampton, VA 23681 USA. NR 31 TC 9 Z9 15 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0376-0421 J9 PROG AEROSP SCI JI Prog. Aeosp. Sci. PD JAN PY 1999 VL 35 IS 1 BP 1 EP 32 DI 10.1016/S0376-0421(98)00008-6 PG 32 WC Engineering, Aerospace SC Engineering GA 160MT UT WOS:000078235000001 ER PT J AU Croll, A Benz, KW AF Croll, A Benz, KW TI Static magnetic fields in semiconductor floating-zone growth SO PROGRESS IN CRYSTAL GROWTH AND CHARACTERIZATION OF MATERIALS LA English DT Review DE floating-zone process; magnetic damping; interface shape; coring effect; dopant striations; thermoelectromagnetic convection ID SI CRYSTAL-GROWTH; AXIAL FIELDS; DOPANT SEGREGATION; METALLIC ALLOYS; SILICON GROWTH; MICROGRAVITY; SOLIDIFICATION; SHAPE; FLOW AB Heat and mass transfer in semiconductor float-zone processing are strongly influenced by convective flows in the zone, originating from sources such as buoyancy convection, thermocapillary (Marangoni) convection, differential rotation, or radio frequency heating. Because semiconductor melts are conducting, flows can be damped by the use of static magnetic fields to influence the interface shape and the segregation of dopants and impurities. An important objective is often the suppression of time-dependent flows and the ensuing dopant striations. In RF-heated Si-FZ-crystals, fields up to 0.5Tesla show some flattening of the interface curvature and a reduction of striation amplitudes. In radiation-heated (small-scale) Si-FZ crystals, fields of 0.2-0.5Tesla already suppress the majority of the dopant striations. The uniformity of the radial segregation is often compromised by using a magnetic field, due to the directional nature of the damping. Transverse fields lead to an asymmetric interface shape and thus require crystal rotation (resulting in rotational dopant striations) to achieve a radially symmetric interface, whereas axial fields introduce a coring effect. A complete suppression of dopant striations and a reduction of the coring to insignificant values, combined with a shift of the axial segregation profile towards a more diffusion-limited case, are possible with axial static fields in excess of 1Tesla. Strong static magnetic fields, however, can also lead to the appearance of thermoelectromagnetic convection, caused by the interaction of thermoelectric currents with the magnetic field. C1 Univ Alabama, Alliance Micrograv Mat Sci & Applicat, NASA, MSFC, Huntsville, AL 35812 USA. Univ Freiburg, Inst Kristallog, D-79104 Freiburg, Germany. RP Croll, A (reprint author), Univ Alabama, Alliance Micrograv Mat Sci & Applicat, NASA, MSFC, SD47, Huntsville, AL 35812 USA. RI Croell, Arne/A-2480-2013 OI Croell, Arne/0000-0002-8673-9994 NR 56 TC 11 Z9 11 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-8974 J9 PROG CRYST GROWTH CH JI Prog. Cryst. Growth Charact. Mater. PY 1999 VL 38 IS 1-4 BP 133 EP 159 PG 27 WC Crystallography; Materials Science, Characterization & Testing SC Crystallography; Materials Science GA 243ZU UT WOS:000083028000006 ER PT S AU Zhu, S White, HW AF Zhu, S White, HW BE Johnson, RN Lee, WY Pickering, MA Sheldon, BW TI Low temperature synthesis of Si-C-N and C-N films by LR-laser assisted ECR-PECVD SO PROPERTIES AND PROCESSING OF VAPOR-DEPOSITED COATINGS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Properties and Processing of Vapor-Deposited Coatings, at the 1998 MRS Fall Meeting CY NOV 30-DEC 02, 1998 CL BOSTON, MA SP Mat Res Soc ID CARBON NITRIDE FILMS; CHEMICAL-VAPOR-DEPOSITION; THIN-FILMS; C3N4 AB A new synthesizing method, IR-laser-assisted electron-cyclotron-resonance plasma-enhanced chemical vapor deposition (LA-ECR-PECVD), has been used to fabricate Si-C-N and C-N films on steel substrates at low temperatures (< 650 degrees C). Methane/nitrogen or carbon dioxide/nitrogen gases are dissociated to methane radicals and nitrogen plasma by the IF-laser and ECR to enhance the species' energy. An IR-laser beam (pulsed Nd:YAG laser, 1064 nm) was introduced into the growth chamber for two purposes: (1) to add Si atoms by ablating a Si target, and (2) to enhance the plasma concentration in the gas phase. An infrared vibration mode located at 1256 cm(-1) wavenumber was observed in Si-C-N and C-N films, although these films have an amorphous phase. The C-N film also has a Raman shift at 1276 cm(-1). The AFM images reveal many islands with a size ranging from 50 nm - 150 nm in films. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SSL, Huntsville, AL 35812 USA. RP Zhu, S (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SSL, Huntsville, AL 35812 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-461-0 J9 MATER RES SOC SYMP P PY 1999 VL 555 BP 365 EP 370 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BN11Q UT WOS:000080757900052 ER PT J AU Colavita, MM AF Colavita, MM TI Fringe visibility estimators for the palomar testbed interferometer SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID STELLAR AB Visibility estimators and their performance are presented for use with the Palomar Testbed Interferometer (PTI). One operational mode of PTI is single-baseline visibility measurement using path length modulation with synchronous readout by a NICMOS-3 infrared array. Visibility is estimated from the fringe quadratures, either incoherently, or using source phase referencing to provide a longer coherent integration time. The visibility estimators differ those used with photon-counting detectors in order to account for biases attributable to detector offsets and read noise. The performance of these estimators is affected not only by photon noise, but also by the detector read noise and errors in estimating the bias corrections, which affect the incoherent and coherent estimators differently. Corrections for visibility loss in the coherent estimators using the measured tracking jitter are also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Colavita, MM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 123 Z9 123 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 1999 VL 111 IS 755 BP 111 EP 117 DI 10.1086/316302 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 158DF UT WOS:000078100200012 ER PT S AU Fijany, A Williams, CP AF Fijany, A Williams, CP BE Williams, CP TI Quantum wavelet transforms: Fast algorithms and complete circuits SO QUANTUM COMPUTING AND QUANTUM COMMUNICATIONS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st NASA International Conference on Quantum Computing and Quantum Communications (QCQC 98) CY FEB 17-20, 1998 CL PALM SPRINGS, CALIFORNIA SP NASA, Joint Propuls Lab, Ctr Integrated Space Microsyst, Ballist Missle Def Org, NASA, Joint Propuls Lab, Ctr Space Microelectr Technol, NASA, Auton & Informat Technol DE quantum computing; quantum algorithms and circuits; wavelet transforms ID EXPERIMENTAL REALIZATION; NETWORKS AB The quantum Fourier transform (QFT), a quantum analog of the classical Fourier transform, has been shown to be a powerful tool in developing quantum algorithms. However, in classical computing there is another class of unitary transforms, the wavelet transforms, which are every bit as useful as the Fourier transform. Wavelet transforms are used to expose the multi-scale structure of a signal and are likely to be useful for quantum image processing and quantum data compression. In this paper, we derive efficient, complete, quantum circuits for two representative quantum wavelet transforms, the quantum Haar and quantum Daubechies D-(4) transforms. Our approach is to factor the classical operators for these transforms into direct sums, direct products and dot products of unitary matrices. In so doing, we find that permutation matrices, a particular class of unitary matrices, play a pivotal role. Surprisingly, we find that operations that are easy and inexpensive to implement classically are not always easy and inexpensive to implement quantum mechanically, and vice versa. In particular, the computational cost of performing certain permutation matrices is ignored classically because they can be avoided explicitly. However, quantum mechanically, these permutation operations must be performed explicitly and hence their cost enters into the full complexity measure of the quantum transform. We consider the particular set of permutation matrices arising in quantum wavelet transforms and develop efficient quantum circuits that implement them. This allows us to design efficient, complete quantum circuits for the quantum wavelet transform. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fijany, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 126-347, Pasadena, CA 91109 USA. NR 22 TC 8 Z9 8 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65514-X J9 LECT NOTES COMPUT SC PY 1999 VL 1509 BP 10 EP 33 PG 24 WC Computer Science, Theory & Methods SC Computer Science GA BP13A UT WOS:000084208300002 ER PT S AU Zak, M Williams, CP AF Zak, M Williams, CP BE Williams, CP TI Quantum recurrent networks for simulating stochastic processes SO QUANTUM COMPUTING AND QUANTUM COMMUNICATIONS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st NASA International Conference on Quantum Computing and Quantum Communications (QCQC 98) CY FEB 17-20, 1998 CL PALM SPRINGS, CALIFORNIA SP NASA, Joint Propuls Lab, Ctr Integrated Space Microsyst, Ballist Missle Def Org, NASA, Joint Propuls Lab, Ctr Space Microelectr Technol, NASA, Auton & Informat Technol ID NUMBER AB We introduce the concept of quantum recurrent networks by incorporating classical feedback loops into conventional quantum networks. We show that the dynamical evolution of such networks, which interleave quantum evolution with measurement and reset operations, exhibit novel dynamical properties finding application in pattern recognition, optimization and simulation. Moreover, decoherence in quantum recurrent networks is less problematic than in conventional quantum network architectures due to the modest phase coherence times needed for network operation. C1 CALTECH, Jet Prop Lab, Ultracomp Grp, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, Ultracomp Grp, Mail Stop 126-347, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65514-X J9 LECT NOTES COMPUT SC PY 1999 VL 1509 BP 75 EP 88 PG 14 WC Computer Science, Theory & Methods SC Computer Science GA BP13A UT WOS:000084208300005 ER PT S AU Williams, CP Gray, AG AF Williams, CP Gray, AG BE Williams, CP TI Automated design of quantum circuits SO QUANTUM COMPUTING AND QUANTUM COMMUNICATIONS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st NASA International Conference on Quantum Computing and Quantum Communications (QCQC 98) CY FEB 17-20, 1998 CL PALM SPRINGS, CALIFORNIA SP NASA, Joint Propuls Lab, Ctr Integrated Space Microsyst, Ballist Missle Def Org, NASA, Joint Propuls Lab, Ctr Space Microelectr Technol, NASA, Auton & Informat Technol ID COMPUTATION; GATES AB In order to design a quantum circuit that performs a desired quantum computation, it is necessary to find a decomposition of the unitary matrix that represents that computation in terms of a sequence of quantum gate operations. To date, such designs have either been found by hand or by exhaustive enumeration of all possible circuit topologies. In this paper we propose an automated approach to quantum circuit design using search heuristics based on principles abstracted from evolutionary genetics, i.e. using a genetic programming algorithm adapted specially for this problem. We demonstrate the method on the task of discovering quantum circuit designs for quantum teleportation. We show that to find a given known circuit design tone which was hand-crafted by a human), the method considers roughly an order of magnitude fewer designs than naive enumeration. In addition, the method finds novel circuit designs superior to those previously known. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, CP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mailstop 126-347, Pasadena, CA 91109 USA. NR 15 TC 15 Z9 15 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65514-X J9 LECT NOTES COMPUT SC PY 1999 VL 1509 BP 113 EP 125 PG 13 WC Computer Science, Theory & Methods SC Computer Science GA BP13A UT WOS:000084208300008 ER PT S AU Zak, M AF Zak, M BE Williams, CP TI Quantum resonance for solving NP-complete problems by simulations SO QUANTUM COMPUTING AND QUANTUM COMMUNICATIONS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st NASA International Conference on Quantum Computing and Quantum Communications (QCQC 98) CY FEB 17-20, 1998 CL PALM SPRINGS, CALIFORNIA SP NASA, Joint Propuls Lab, Ctr Integrated Space Microsyst, Ballist Missle Def Org, NASA, Joint Propuls Lab, Ctr Space Microelectr Technol, NASA, Auton & Informat Technol AB Quantum analog computing is based upon similarity between mathematical formalism of a quantum phenomenon and phenomena to be analyzed. In this paper, the mathematical formalism of quantum resonance combined with tensor product decomposability of unitary evolutions is mapped onto a class of NP-complete combinatorial problems. C1 CALTECH, Jet Prop Lab, Ultracomp Grp, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, Ultracomp Grp, Mail Stop 525-3660, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65514-X J9 LECT NOTES COMPUT SC PY 1999 VL 1509 BP 160 EP 166 PG 7 WC Computer Science, Theory & Methods SC Computer Science GA BP13A UT WOS:000084208300013 ER PT S AU Cerf, NJ AF Cerf, NJ BE Williams, CP TI Information-theoretic aspects of quantum copying SO QUANTUM COMPUTING AND QUANTUM COMMUNICATIONS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 1st NASA International Conference on Quantum Computing and Quantum Communications (QCQC 98) CY FEB 17-20, 1998 CL PALM SPRINGS, CALIFORNIA SP NASA, Joint Propuls Lab, Ctr Integrated Space Microsyst, Ballist Missle Def Org, NASA, Joint Propuls Lab, Ctr Space Microelectr Technol, NASA, Auton & Informat Technol ID ERROR-CORRECTION; CLONING; CHANNELS AB An information-theoretic approach to quantum copying is discussed, relying on the notion of quantum loss, a quantity that reflects the transmission quality in a noisy quantum channel. More specifically, an entropic no-cloning inequality is derived for a Hilbert space of arbitrary dimension, which describes the tradeoff between the losses of the channels leading to the two copies. Then, focusing on quantum bits, a family of Pauli cloning machines is introduced. These machines produce two imperfect copies of a single quantum bit that emerge from two distinct Pauli channels. The balance between the quality of the two copies is shown to result from a genuine complementarity principle. In the special case where the two outputs are associated with depolarizing channels of probability p and p', the domain in (root p, root p')-space located inside a particular ellipse representing close-to-perfect cloning is forbidden. Finally, the class of symmetric Pauli cloning machines is used to provide an upper bound on the quantum capacity of the Pauli channel of probabilities p(x), p(y) and p(z). The capacity is proven to be vanishing if (root p(x), root p(y), root p(z)) lies outside an ellipsoid whose pole coincides with the depolarizing channel that underlies the universal cloning machine. C1 CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Informat & Comp Technol Res Sect, Pasadena, CA 91109 USA. Free Univ Brussels, Ctr Nonlinear Phenomena & Complex Syst, B-1050 Brussels, Belgium. RP Cerf, NJ (reprint author), CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65514-X J9 LECT NOTES COMPUT SC PY 1999 VL 1509 BP 218 EP 234 PG 17 WC Computer Science, Theory & Methods SC Computer Science GA BP13A UT WOS:000084208300019 ER PT J AU Gaspari, G Cohn, SE AF Gaspari, G Cohn, SE TI Construction of correlation functions in two and three dimensions SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE compactly-supported; convolution; correlation-functions; data-assimilation; space-limited ID RANGE FORECAST ERRORS; DATA ASSIMILATION; STATISTICAL STRUCTURE; RADIOSONDE DATA; COVARIANCE; SYSTEM AB This article focuses on the construction, directly in physical space, of simply parametrized covariance functions for data-assimilation applications. A self-contained, rigorous mathematical summary of relevant topics from correlation theory is provided as a foundation for this construction. Covariance and correlation functions are defined, and common notions of homogeneity and isotropy are clarified. Classical results are stated, and proven where instructive. Included are smoothness properties relevant to multivariate statistical-analysis algorithms where wind/wind and wind/mass correlation models are obtained by differentiating the correlation model of a mass variable. The Convolution Theorem is introduced as the primary tool used to construct classes of covariance and cross-covariance functions on three-dimensional Euclidean space R-3. Among these are classes of compactly supported functions that restrict to covariance and cross-covariance functions on the unit sphere S-2, and that vanish identically on subsets of positive measure on S-2. It is shown that these covariance and cross-covariance functions on S-2, referred to as being space-limited, cannot be obtained using truncated spectral expansions. Compactly supported and space-limited covariance functions determine sparse covariance matrices when evaluated on a grid, thereby easing computational burdens in atmospheric data-analysis algorithms. Convolution integrals leading to practical examples of compactly supported covariance and cross-covariance functions on R-3 are reduced and evaluated. More specifically, suppose that g(i) and g(j) are radially symmetric functions defined on R-3 such that g(i) (x) = 0 for \\x\\ > d(i) and g(j)(x) = 0 for \\x\\ > d(j), 0 < d(i),d(j) where \\.\\denotes Euclidean distance in R-3. The parameters d(i) and d(j) are 'cut-off' distances. Closed-form expressions are determined for classes of convolution cross-covariance functions less than or equal to infinity, C-ij (x, y) := (g(i) *g(j))(x - y), i not equal j, and convolution covariance functions C-ii (x, y) := (g(i) * g(i))(x - y), vanishing for \\x - y\\ > d(i) + d(j) and \\x - y\\ > 2d(i), respectively. Additional covariance functions on R-3 are constructed using convolutions over the real numbers R, rather than R-3. Families of compactly supported approximants to standard second- and third-order autoregressive functions are constructed as illustrative examples. Compactly supported covariance functions of the form C(x, y) := C-0(\\x - y\\), x, y is an element of R-3, where the functions C-0(r) for r is an element of R are 5th-order piecewise rational functions, are also constructed. These functions are used to develop space-limited product covariance functions B(x, y) C(x, y), x, y is an element of S2 approximating given covariance functions B(x, y) supported on all of S-2 x S-2. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD USA. RP Gaspari, G (reprint author), NASA, Goddard Space Flight Ctr, Code 9103, Greenbelt, MD 20771 USA. RI Cohn, Stephen/K-1954-2012 OI Cohn, Stephen/0000-0001-8506-9354 NR 45 TC 712 Z9 742 U1 3 U2 36 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JAN PY 1999 VL 125 IS 554 BP 723 EP 757 DI 10.1256/smsqj.55416 PN B PG 35 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 179VK UT WOS:000079350100016 ER PT B AU Nandra, K AF Nandra, K BE Ferland, G Baldwin, J TI X-ray dependencies on luminosity in AGN SO QUASARS AND COSMOLOGY SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Quasars and Cosmology CY MAY 18-22, 1998 CL LA SERENA, CHILE SP Astron Soc Pacific ID ACTIVE GALACTIC NUCLEI; SEYFERT-1 GALAXIES; LINE-PROFILES; QUASARS; VARIABILITY; EMISSION; OBJECTS; DISK AB Several X-ray properties of active galactic nuclei depend, or appear to depend, on their luminosity. It has long been suggested that alpha(ox), the X-ray "loudness" decreases with luminosity. There never has been a satisfactory explanation of this observational claim, and the statistical soundness of the result has been disputed. The earliest systematic studies of the X-ray variability of AGN showed that these properties also depend on luminosity. In particular, the normalization of the power spectrum, or alternatively the the variability amplitude, are anti-correlated with luminosity. Most recently, tentative evidence from Ginga for an X-ray Baldwin effect a decrease in the Fe K alpha equivalent width with luminosity - has been confirmed and extended by ASCA. The new data show that the reduction in strength is accompanied by changes in profile. These results will be described and their interpretation discussed. C1 NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. RP Nandra, K (reprint author), NASA, Goddard Space Flight Ctr, LHEA, Code 661, Greenbelt, MD 20771 USA. NR 28 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-83-X J9 ASTR SOC P PY 1999 VL 162 BP 65 EP 74 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN27U UT WOS:000081412200005 ER PT J AU Lucas, JN Deng, W Oram, SW Hill, FS Durante, M George, K Wu, H Owens, CL Yang, T AF Lucas, JN Deng, W Oram, SW Hill, FS Durante, M George, K Wu, H Owens, CL Yang, T TI Theoretical and experimental tests of a chromosomal fingerprint for densely ionizing radiation based on F ratios calculated from stable and unstable chromosome aberrations SO RADIATION RESEARCH LA English DT Article ID DIRECT BIOLOGICAL EVIDENCE; HIROSHIMA ATOMIC-BOMB; HUMAN-LYMPHOCYTES; IN-SITU; PERICENTRIC INVERSIONS; ALPHA-PARTICLES; CENTRIC RINGS; ACUTE-X; IRRADIATION; HYBRIDIZATION AB In the present study, F ratios for both stable chromosome aberrations, i.e. ratios of translocations to pericentric inversions, and unstable aberrations, i.e. dicentrics and centric rings, were measured using fluorescence in situ hybridization. F ratios for stable aberrations measured after exposure to low (2.89 Gy Co-60 gamma rays) and high-LET (0.25 Gy Fe-56 ions; 1.25 Gy Fe-56 ions; 3.0 Gy C-12 ions) radiation were 6.5 +/- 1.5, 4.7 +/- 1.6, 9.3 +/- 2.5 and 10.4 +/- 3.0, respectively. F ratios for unstable aberrations measured after low (2.89 Gy Co-60 gamma rays) and high-LET (0.25 Gy Fe-56 ions; 3.0 Gy C-12 ions) radiations were 6.5 +/- 1.6, 6.3 +/- 2.3 and 11.1 +/- 3.7, respectively. No significant difference between the F ratios for low- and high-LET radiation was found. Further tests on the models for calculation of the F ratio proposed by Brenner and Sachs (Radiat. Res. 140, 134-142, 1994) showed that the F ratio may not be straightforward as a practical fingerprint for densely ionizing radiation. (C) 1999 by Radiation Research Society. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Sichuan Inst Radiat Hlth & Protect, Sichuan Inst Occupat Hlth, Chengdu 610041, Peoples R China. Univ Naples Federico II, Dipartimento Sci Fisiche, I-80125 Naples, Italy. NASA, Lyndon B Johnson Space Ctr, Div Med Sci, Houston, TX 77058 USA. RP Lucas, JN (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. RI Deng, Wen/C-4154-2009; Durante, Marco/K-1315-2014; OI Durante, Marco/0000-0002-4615-553X NR 44 TC 14 Z9 17 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JAN PY 1999 VL 151 IS 1 BP 85 EP 91 DI 10.2307/3579752 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 154VQ UT WOS:000077910400011 PM 9973089 ER PT J AU Ishimaru, A Kuga, Y Liu, J Kim, Y Freeman, T AF Ishimaru, A Kuga, Y Liu, J Kim, Y Freeman, T TI Ionospheric effects on synthetic aperture radar at 100 MHz to 2 GHz SO RADIO SCIENCE LA English DT Article AB Recently, there has been increasing interest in the use of spaceborne synthetic aperture radar (SAR) for measuring forest biomass. However, it is noted that conventional SAR using C-band or higher frequencies cannot penetrate into foliage, and therefore the biomass measurements require longer wavelengths, typically P-band (500 MHz). It is also known that the ionosphere is highly dispersive, causing group delay and broadening of pulses. The variance of the refractive index fluctuations due to turbulence is approximately proportional to f(-4). In addition, the Faraday rotation due to the geomagnetic field in the ionosphere becomes significant. This paper presents an analysis with numerical examples of the following effects in the frequency range from 100 MHz to 2 GHz in order to show the frequency dependence and the effects of total electron content (TEC) of the ionosphere. First, the ionospheric turbulence can reduce the coherent length below the equivalent aperture size, and the azimuthal resolution becomes greater than D/2, where D is the antenna aperture size. Second, the ionospheric dispersion causes a shift of the imagery due to the group velocity. Third, the dispersion also creates broadening of the pulse. In addition, multiple scattering due to ionospheric turbulence gives rise to pulse broadening. Fourth, we consider the Faraday rotation effect and show that the ellipticity change is negligible, but the orientation angle changes significantly at P- band. Numerical examples are shown using typical ionospheric parameters, turbulence spectrum, and TEC values. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ishimaru, A (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. EM ishimaru@ee.washington.edu; ykuga@u.washington.edu; junliu@ee.washington.edu; ykim@delphi.jpl.nasa.gov; tony.freeman@jpl.nasa.gov NR 17 TC 49 Z9 62 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN-FEB PY 1999 VL 34 IS 1 BP 257 EP 268 DI 10.1029/1998RS900021 PG 12 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 161QG UT WOS:000078299800020 ER PT B AU Jaffe, RL AF Jaffe, RL BE Kamat, PV Guldi, DM Kadish, KM TI Quantum chemistry study of chemical functionalization reactions of fullerenes and carbon nanotubes SO RECENT ADVANCES IN THE CHEMISTRY AND PHYSICS OF FULLERENES AND RELATED MATERIAL, VOL 7 SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 12th International Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials at the 195th Meeting of the Electrochemical-Society CY MAY 02-08, 1999 CL SEATTLE, WA SP Electrochem Soc ID C-60; BENZYNE; ADDUCTS; PROBES; TIPS AB Cycloaddition reactions of fullerenes and single wall carbon nanotubes have been studied by ab initio quantum chemistry calculations using non-local hybrid density functional theory. Known reactions of C-60 with benzyne, dichlorocarbene (CCl2) and azomethine ylide are used to validate the computational model. For C60, the adduct binding energies are all large. However, results for nanotube sidewalls and endcaps show the adducts to be considerably less stable. While benzyne cycloaddition reaction with nanotubes is feasible, the CCl2 reaction is not likely to occur. The adduct binding energies exhibit no correlation with substrate distortion energies, indicating that strain energy is not an important factor for the determination of reactivity. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jaffe, RL (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 29 TC 5 Z9 5 U1 2 U2 4 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-234-6 J9 ELEC SOC S PY 1999 VL 99 IS 12 BP 153 EP 162 PG 4 WC Thermodynamics; Chemistry, Physical; Electrochemistry; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Thermodynamics; Chemistry; Electrochemistry; Physics; Spectroscopy GA BN84T UT WOS:000083175200017 ER PT S AU Lopez-Valverde, MA Lopez-Puertas, M Taylor, FW Gunson, MR AF Lopez-Valverde, MA Lopez-Puertas, M Taylor, FW Gunson, MR BE Rodgers, CD Guymer, TH Palaniappan, K TI Correlation between ISAMS and ATMOS measurements of CO in the middle atmosphere SO REMOTE SENSING: EARTH, OCEAN AND ATMOSPHERE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A1 1 and A2 1 Symposia COSPAR Scientific Commission A on Remote Sensing - Earth, Ocean and Atmosphere, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP European Space Agcy, Scientif Commiss C, Royal Meteorol Soc, Comm Space Res, Scientif Comm Ocean Res ID MESOSPHERIC SOUNDER; VALIDATION AB Measurements of IR emissions from CO at 4.6 mu m in the middle atmosphere were recorded for nearly one year, from September 1991 to July 1992 by the Improved Stratospheric and Mesospheric Sounder (ISAMS) on board the Upper Atmosphere Research Satellite (UARS). These have been used to retrieve carbon monoxide abundances and study their distribution and variability in the middle atmosphere. Observations of carbon monoxide in this atmospheric region and from transitions of the same vibrational-rotational band were also carried out, using the solar occultation technique with fine altitude resolution, by the high resolution interferometer ATMOS during the ATLAS-1 mission (late March and early April 1992). Comparisons between these simultaneous emission and absorption experiments have been performed in order to improve and validate both data sets. Some of the first results and conclusions are presented and discussed. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lopez-Valverde, MA (reprint author), CSIC, Inst Astrofis Andalucia, Apdo 3004, E-18080 Granada, Spain. RI Lopez Puertas, Manuel/M-8219-2013 OI Lopez Puertas, Manuel/0000-0003-2941-7734 NR 5 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043639-0 J9 ADV SPACE RES PY 1999 VL 22 IS 11 BP 1517 EP 1520 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM91C UT WOS:000080096000009 ER PT S AU Owe, M de Jeu, R Van de Griend, A AF Owe, M de Jeu, R Van de Griend, A BE Cecchi, G Engman, ET Zilioli, E TI Estimates of long term surface soil moisture in the midwestern US derived from satellite microwave observations SO REMOTE SENSING FOR EARTH SCIENCE, OCEAN, AND SEA ICE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Remote Sensing for Earth Science, Ocean, and Sea Ice Applications CY SEP 20-24, 1999 CL FLORENCE, ITALY SP Univ Florence, Dept Earth Sci, European Opt Soc, SPIE, CNR, NASA, Italian Soc Opt & Photon, Italian Space Agcy DE remote sensing; microwave; SMMR; soil moisture; vegetation indices ID VEGETATION OPTICAL DEPTH; SINGLE SCATTERING ALBEDO; FREQUENCIES; MODEL AB A database of long-term soil moisture was compared to satellite microwave observations over a test site in the Midwestern United States. Ground measurements of average volumetric surface soil moisture in the top ten cm were made several times per month at 19 locations throughout the state of Illinois. Nighttime microwave brightness temperatures were observed at a frequency of 6.6 GHz, by the Scanning Multichannel Microwave Radiometer (SMMR), onboard the Nimbus 7 satellite. At 6.6 GHz, the instrument provides a spatial resolution of approximately 150 ion and a temporal frequency over the test area of about 3 nighttime orbits per week Vegetation radiative transfer characteristics, such as the canopy transmissivity, were estimated from vegetation indices such as the Normalized Difference Vegetation Index (NDVI) and the 37 GHz Microwave Polarization Difference Index (MPDI). Because the time of satellite coverage does not always coincide with the ground measurements of sail moisture, the existing ground data were used to calibrate a water balance for the top TO cm surface layer in order to interpolate daily surface moisture values. Such a climate-based approach is often more appropriate for estimating large-area average soil moisture because meteorological data are generally more spatially representative than isolated point measurements of soil moisture. Passive microwave remote sensing presents the greatest potential for providing regular spatially representative estimates of surface sail moisture at global scales. Real time estimates should improve weather and climate modelling: efforts, while the development of historical data sets will provide necessary information for simulation and validation of long-term climate and global change studies. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Owe, M (reprint author), NASA, Goddard Space Flight Ctr, MC 974, Greenbelt, MD 20771 USA. NR 25 TC 0 Z9 0 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3463-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3868 BP 16 EP 23 DI 10.1117/12.373100 PG 8 WC Geology; Geosciences, Multidisciplinary; Remote Sensing; Optics SC Geology; Remote Sensing; Optics GA BP39S UT WOS:000084986600003 ER PT J AU Lefsky, MA Harding, D Cohen, WB Parker, G Shugart, HH AF Lefsky, MA Harding, D Cohen, WB Parker, G Shugart, HH TI Surface lidar remote sensing of basal area and biomass in deciduous forests of eastern Maryland, USA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID NORTHERN HARDWOOD FORESTS; LASER SCANNER DATA; AIRBORNE LIDAR; CANOPY; HEIGHT; STANDS; VOLUME; SYSTEM; STRATIFICATION; SUCCESSION AB A method of predicting two forest stand structure attributes, basal area and aboveground biomass, from measurements of forest vertical structure was developed and tested using field and remotely sensed canopy structure measurements. Coincident estimates of the vertical distribution of canopy structure measurements. Coincident estimates of the vertical distribution of canopy surface area (the canopy height profile), and field-measured stand structure attributes were acquired for two data sets. the chronosequence data set consists of 48 plots in stands distributed within 25 miles of Annapolis, MD, with canopy height profiles measured in the field using the optical-quadrat method. The stem-map data set consists of 75 plots subsetted from a single 32 ha stem-mapped stand, with measurements of their canopy height profiles made using the SLICER (Scanning Lidar Imager of Canopies by Echo Recovery) instrument, an airborne surface lidar system. Four height indices, maximum, median, mean, and quadratic mean canopy height (QMCH) were calculated from the canopy height profiles. Regressions between the indices and stand basal area and biomass were developed using the chronosequence data set. The regression equations developed from the chronosequence data set were then applied to height indices calculated from the remotely sensed canopy height profiles from the stem map data set, and the ability of the regression equations to predict the stem map plot's stand structure attributes was then evaluated. The QMCH was found to explain the most variance in the chronosequence data set's stand structure attributes, and to most accurately predict the values of the same attributes in the stem map data set. For the chronosequence data set, the QMCH predicted 70% of variance in stand basal area, and 80% of variance in aboveground biomass, and remained nonasymptotic with basal areas up to 50 m(2) ha(-1), and aboveground biomass values up to 450 Mg ha(-1). When applies to the stem-map data set, the regression equations resulted in basal areas that were, on average, underestimated by 2.1 m(2) ha(-1), and biomass values were underestimated by 16 Mg ha(-1), and explained 37% and 33% of variance, respectively. Differences in the magnitude of the coefficients of determination were due to the wider range of stand conditions found in the chronosequence data set; the standard deviation of residual values were lower in the stem map data set than on the chronosequence data sets. Stepwise multiple regression was performed to predict the two stand structure attributes using the canopy height profile data directly as independent variables, but they did not improve the accuracy of the estimates over the height index approach. Published by Elsevier Science Inc. C1 US Forest Serv, USDA, Pacific NW Res Stn, Forestry Sci Lab, Corvallis, OR 97331 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. RP Lefsky, MA (reprint author), US Forest Serv, USDA, Pacific NW Res Stn, Forestry Sci Lab, 3200 SW Jefferson Way, Corvallis, OR 97331 USA. RI Lefsky, Michael/A-7224-2009; Shugart, Herman/C-5156-2009; Harding, David/F-5913-2012; OI Parker, Geoffrey/0000-0001-7055-6491 NR 44 TC 346 Z9 374 U1 14 U2 106 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN PY 1999 VL 67 IS 1 BP 83 EP 98 DI 10.1016/S0034-4257(98)00071-6 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 151KV UT WOS:000077720000006 ER PT S AU Nelson, ML Maly, K Zubair, M Shen, SNT AF Nelson, ML Maly, K Zubair, M Shen, SNT BE Abiteboul, S Vercoustre, AM TI SODA: Smart Objects, Dumb Archives SO RESEARCH AND ADVANCED TECHNOLOGY FOR DIGITAL LIBRARIES, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd European Conference on Research and Advanced Technology for Digital Libraries (ECDL 99) CY SEP 22-24, 1999 CL PARIS, FRANCE SP French Natl Inst Res Comp Sci & Control, Frence Natl Lib, European Commiss, TMR Program, European Consortium Informat & Math AB We present the Smart Object, Dumb Archive (SODA) model for digital libraries (DLs). The SODA model transfers functionality traditionally associated with archives to the archived objects themselves. We are exploiting this shift of responsibility to facilitate other DL goals, such as interoperability, object intelligence and mobility, and heterogeneity. Objects in a SODA DL negotiate presentation of content and handle their own terms-and conditions. In this paper we present implementations of our smart objects, buckets, and our dumb archive (DA). We discuss the status of buckets and DA and how they are used in a variety of DL projects. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23592 USA. RP Nelson, ML (reprint author), NASA, Langley Res Ctr, MS 158, Hampton, VA 23681 USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66558-7 J9 LECT NOTES COMPUT SC PY 1999 VL 1696 BP 453 EP 464 PG 12 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA BP88L UT WOS:000086484700026 ER PT J AU Guice, J AF Guice, J TI Designing the future: the culture of new trends in science and technology SO RESEARCH POLICY LA English DT Article DE technology trends; rhetoric; defense advanced research projects agency; neural computing AB In order to influence major trends in research and development, interested groups use technical arguments, among other means, to promote shared models of the future. This article proposes that two specific forms of argument are endemic to trend-promotion in science and technology: intended self-fulfilling prophecy and emotional rhetoric. It is illustrated with a close reading of a document by the US Defense Advanced Research Projects Agency concerning a field of information technology. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Guice, J (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM jguice@concentric.net NR 83 TC 28 Z9 28 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-7333 J9 RES POLICY JI Res. Policy PD JAN PY 1999 VL 28 IS 1 BP 81 EP 98 DI 10.1016/S0048-7333(98)00105-X PG 18 WC Management; Planning & Development SC Business & Economics; Public Administration GA 155EH UT WOS:000077932900005 ER PT J AU Hollenbach, DJ Tielens, AGGM AF Hollenbach, DJ Tielens, AGGM TI Photodissociation regions in the interstellar medium of galaxies SO REVIEWS OF MODERN PHYSICS LA English DT Review ID PHOTON-DOMINATED REGIONS; INTER-STELLAR CLOUDS; H-II REGIONS; MOLECULAR-HYDROGEN EMISSION; WARM NEUTRAL HALOS; POLYCYCLIC AROMATIC-HYDROCARBONS; FAR-INFRARED SPECTROSCOPY; REFLECTION NEBULA NGC-7023; REGULATED STAR FORMATION; MICRON C-II AB The interstellar medium of galaxies is the reservoir out of which stars are born and into which stars inject newly created elements as they age. The physical properties of the interstellar medium are governed in part by the radiation emitted by these stars. Far-ultraviolet (6 eV100 mu m], and narrowband window [8 mu m and 12 mu m], scanning thermistor bolometer sensor units; and of inflight calibration systems. Between the ground and initial on-orbit calibrations, the TRMM CERES bolometers and the builtin, flight calibration system sources maintained their filtered radiance measurement ties to ITS-90 at the +/- 0.2 Wm(-2)sr(-1) precision level. On-orbit calibration studies indicate that the radiance measurements were stable at the +/- 0.2 Wm(-2)sr(-1) precision level. The ground and on-orbit calibration results are presented and discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lee, RB (reprint author), NASA, Langley Res Ctr, MS 420,Bldg 1250, Hampton, VA 23681 USA. NR 20 TC 9 Z9 9 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3465-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3870 BP 389 EP 396 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BP56D UT WOS:000085492800040 ER PT J AU Lewis, RM Torczon, V AF Lewis, RM Torczon, V TI Pattern search algorithms for bound constrained minimization SO SIAM JOURNAL ON OPTIMIZATION LA English DT Article DE bound constrained optimization; convergence analysis; pattern search methods; direct search methods; globalization strategies; alternating variable search; axial relaxation; local variation; coordinate search; evolutionary operation; multidirectional search ID CONVERGENCE AB We present a convergence theory for pattern search methods for solving bound constrained nonlinear programs. The analysis relies on the abstract structure of pattern search methods and an understanding of how the pattern interacts with the bound constraints. This analysis makes it possible to develop pattern search methods for bound constrained problems while only slightly restricting the flexibility present in pattern search methods for unconstrained problems. We prove global convergence despite the fact that pattern search methods do not have explicit information concerning the gradient and its projection onto the feasible region and consequently are unable to enforce explicitly a notion of sufficient feasible decrease. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. Coll William & Mary, Dept Comp Sci, Williamsburg, VA 23187 USA. RP Lewis, RM (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 132C, Hampton, VA 23681 USA. NR 18 TC 231 Z9 244 U1 2 U2 7 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1052-6234 J9 SIAM J OPTIMIZ JI SIAM J. Optim. PY 1999 VL 9 IS 4 BP 1082 EP 1099 DI 10.1137/S1052623496300507 PG 18 WC Mathematics, Applied SC Mathematics GA 266ZN UT WOS:000084330300014 ER PT S AU Pohorille, A Wilson, MA Schweighofer, K AF Pohorille, A Wilson, MA Schweighofer, K BE Pratt, LR Hummer, G TI Electrostatic properties of aqueous interfaces probed by small solutes SO SIMULATION AND THEORY OF ELECTROSTATIC INTERACTIONS IN SOLUTION: COMPUTATIONAL CHEMISTRY, BIOPHYSICS, AND AQUEOUS SOLUTIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Treatment of Electrostatic Interactions in Computer Simulations of Condensed Media CY JUN 23-25, 1999 CL SANTA FE, NM SP Ctr Nonlinear Studies, Los Alamos Natl Lab, Univ Utah, Henry Eyring Ctr Theoret Chem ID MOLECULAR-DYNAMICS SIMULATION; LIPID BILAYER-MEMBRANES; PHOSPHOLIPID-BILAYERS; POTENTIAL FUNCTIONS; WATER INTERFACE; ANESTHETICS; NMR; DIPALMITOYLPHOSPHATIDYLCHOLINE; DIFFUSION; CAVITIES AB The excess chemical potentials of methane and its four fluorinated derivatives across the water-hexane, water-octanol, water-glycerol l-monooleate and water-1-palmitoyl 2-oleoyl sn-glycero 3-phosphatidylcholine (POPC) interfaces are calculated using the particle insertion method, in all cases, the polar species exhibit interfacial minima indicating that these molecules tend to accumulate in the interfacial region, while the non-polar molecules exhibit no such minimum. The excess chemical potentials are further partitioned into electrostatic and non-electrostatic terms. For polar molecules, the electrostatic term changes nearly linearly over the distance of approximately 10 Angstrom in the interfacial region and appears to depend only weakly on the nature of the interface. Solute molecules are not oriented isotropically at the interface, but tend to align themselves with the excess electric field created by the anisotropic interfacial environment. Using dipoles in a cavity as models, it is further shown that, in the water-POPC system, the electrostatic term changes with the size of the dipole according to the predictions of linear response theory. This approximation does not work as well for the other interfacial systems investigated. This may be an artifact due to the neglect of long-range effects in those simulations. The non-electrostatic term, dominated by the reversible work of cavity formation, shows interfacially induced structure. Ln particular, it is responsible for a maximum of the excess chemical potential on the dense, water side of the water-POPC interface. The results of this study provide guidance to developing simple but accurate implicit models of interfacial systems. C1 NASA, Ames Res Ctr, Biomol & Cellular Modeling Program, Moffett Field, CA 94035 USA. RP Pohorille, A (reprint author), NASA, Ames Res Ctr, Biomol & Cellular Modeling Program, Moffett Field, CA 94035 USA. NR 37 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-906-8 J9 AIP CONF PROC PY 1999 VL 492 BP 492 EP 509 DI 10.1063/1.1301544 PG 18 WC Biophysics; Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Biophysics; Chemistry; Physics GA BP14C UT WOS:000084221000026 ER PT B AU Estlin, T Gray, A Mann, T Rabideau, G Castano, R Chien, S Mjolsness, E AF Estlin, T Gray, A Mann, T Rabideau, G Castano, R Chien, S Mjolsness, E GP AAAI AAAI TI An integrated system for multi-rover scientific exploration SO SIXTEENTH NATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE (AAAI-99)/ELEVENTH INNOVATIVE APPLICATIONS OF ARTIFICIAL INTELLIGENCE (IAAI-99) LA English DT Proceedings Paper CT 16th National Conference on Artificial Intelligence (AAAI-99)/11th Conference on Innovative Applications of Artificial Intelligence (IAAI-99) CY JUL 18-22, 1999 CL ORLANDO, FL SP Amer Assoc Artificial Intelligence, ACM,SIGART, US Def, Adv Res Projects Agcy, Microsoft Corp, USN, Res Lab, USN, Off Naval Res, NASA, Ames Res Ctr, NSF, Rent Comp ID EM ALGORITHM; MIXTURE AB This paper describes an integrated system for coordinating multiple rover behavior with the overall goal of collecting planetary surface data. The Multi-Rover Integrated Science Understanding System combines concepts from machine learning with planning and scheduling to perform autonomous scientific exploration by cooperating revers. The integrated system utilizes a novel machine learning clustering component to analyze science data and direct new science activities. A planning and scheduling system is employed to generate rover plans for achieving science goals and to coordinate activities among revers. We describe each of these components and discuss some of the key integration issues that arose during development and influenced both system design and performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tara.estlin@jpl.nasa.gov; alexander.gray@jpl.nasa.gov; tobias.mann@jpl.nasa.gov; gregg.rabideau@jpl.nasa.gov; rebecca.castano@jpl.nasa.gov; steve.chien@jpl.nasa.gov; eric.mjolsness@jpl.nasa.gov NR 20 TC 2 Z9 2 U1 0 U2 1 PU ASSOC ADVANCEMENT ARTIFICIAL INTELLIGENCE PI PALO ALTO PA 2275 E BAYSHORE RD, STE 160, PALO ALTO, CA 94303 USA BN 0-262-51106-1 PY 1999 BP 613 EP 620 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ85T UT WOS:000089853000086 ER PT B AU Rabideau, G Chien, S Willis, J Mann, T AF Rabideau, G Chien, S Willis, J Mann, T GP AAAI AAAI TI Using iterative repair to automate planning and scheduling of shuttle payload operations SO SIXTEENTH NATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE (AAAI-99)/ELEVENTH INNOVATIVE APPLICATIONS OF ARTIFICIAL INTELLIGENCE (IAAI-99) LA English DT Proceedings Paper CT 16th National Conference on Artificial Intelligence (AAAI-99)/11th Conference on Innovative Applications of Artificial Intelligence (IAAI-99) CY JUL 18-22, 1999 CL ORLANDO, FL SP Amer Assoc Artificial Intelligence, ACM,SIGART, US Def, Adv Res Projects Agcy, Microsoft Corp, USN, Res Lab, USN, Off Naval Res, NASA, Ames Res Ctr, NSF, Rent Comp AB This paper describes the DATA-CHASER Automated Planner/Scheduler (DCAPS) system for automated generation and repair of command sequences for the DATA-CHASER shuttle payload. DCAPS uses general Artificial Intelligence (AI) heuristic search techniques, including an iterative repair framework in which the system iteratively resolves conflicts with the state, resource, and temporal constraints of the payload activities. DCAPS was used in the operations of the shuttle payload for the STS-85 shuttle flight in August 1997 and enabled an 80% reduction in mission operations effort and a 40% increase in science return. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rabideau, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 1 Z9 1 U1 0 U2 1 PU AMER ASSOC ARTIFICIAL INTELLIGENCE PI MENLO PK PA 445 BURGESS DR, MENLO PK, CA 94025 USA BN 0-262-51106-1 PY 1999 BP 813 EP 820 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ85T UT WOS:000089853000114 ER PT B AU Fisher, F Estlin, T Mutz, D Chien, S AF Fisher, F Estlin, T Mutz, D Chien, S GP AAAI AAAI TI Using Artificial Intelligence planning to generate antenna tracking plans SO SIXTEENTH NATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE (AAAI-99)/ELEVENTH INNOVATIVE APPLICATIONS OF ARTIFICIAL INTELLIGENCE (IAAI-99) LA English DT Proceedings Paper CT 16th National Conference on Artificial Intelligence (AAAI-99)/11th Conference on Innovative Applications of Artificial Intelligence (IAAI-99) CY JUL 18-22, 1999 CL ORLANDO, FL SP Amer Assoc Artificial Intelligence, ACM,SIGART, US Def, Adv Res Projects Agcy, Microsoft Corp, USN, Res Lab, USN, Off Naval Res, NASA, Ames Res Ctr, NSF, Rent Comp AB This paper describes the application of Artificial Intelligence planning techniques to the problem of antenna track plan generation for a NASA Deep Space Communications Station. The described system enables an antenna communications station to automatically respond to it set of tracking goals by correctly configuring the appropriate hardware and software to provide the requested communication services. To perform this task, the Automated Scheduling and Planning Environment (ASPEN) has been applied to automatically produce antenna tracking plans that are tailored to support a set of input goals. In this paper, we describe the antenna automation problem, the ASPEN planning and scheduling system, how ASPEN is used to generate antenna track plans, the results of several technology demonstrations, and future work utilizing dynamic planning technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fisher, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 1 PU AMER ASSOC ARTIFICIAL INTELLIGENCE PI MENLO PK PA 445 BURGESS DR, MENLO PK, CA 94025 USA BN 0-262-51106-1 PY 1999 BP 856 EP 863 DI 10.1109/ICIAP.1999.797702 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ85T UT WOS:000089853000120 ER PT B AU Newman, JC AF Newman, JC BE Ravichandran, KS Ritchie, RO Murakami, Y TI Application of small-crack theory to aircraft materials SO SMALL FATIGUE CRACKS: MECHANICS, MECHANISMS, AND APPLICATIONS LA English DT Proceedings Paper CT 3rd Engineering Foundation International Conference on Small Fatigue Cracks CY DEC 06-11, 1998 CL OAHU, HI SP Engn Fdn DE cracks; fracture mechanics; stress-intensity factor; crack closure; aluminum alloy; steel ID SHORT FATIGUE CRACKS; GROWTH AB Over the past two decades, studies on the growth of small cracks have led to the observation that Fatigue life of many engineering materials is primarily "crack growth" from microstructural features, such as inclusion particles, voids, slip-bands or from manufacturing defects. This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using "small-crack theory" under various loading conditions. Constraint factors, to account for three-dimensional effects, were selected to correlate large-crack growth rate data as a function of the effective stress-intensity factor range (Delta K-eff) under constant-amplitude loading. Modifications to the Delta K-eff-rate relations in the near-threshold regime were needed to fit measured small-crack growth rate behavior. The model was then used to calculate small- and large-crack growth rates, and to predict total fatigue lives, for notched and un-notched specimens under constant-amplitude and spectrum loading. Fatigue lives were predicted using the crack-growth relations and micro-structural features like those that initiated cracks in the fatigue specimens. Results from the tests acid analyses agreed well. C1 NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. NR 24 TC 2 Z9 2 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-08-043011-2 PY 1999 BP 431 EP 442 DI 10.1016/B978-008043011-9/50040-5 PG 12 WC Engineering, Mechanical SC Engineering GA BP92Z UT WOS:000086647400039 ER PT B AU Piascik, RS AF Piascik, RS BE Ravichandran, KS Ritchie, RO Murakami, Y TI The growth of small cracks in airframe structure SO SMALL FATIGUE CRACKS: MECHANICS, MECHANISMS, AND APPLICATIONS LA English DT Proceedings Paper CT 3rd Engineering Foundation International Conference on Small Fatigue Cracks CY DEC 06-11, 1998 CL OAHU, HI SP Engn Fdn DE small crack; initiation; growth; fretting; aluminum; riveted joint; aircraft; fuselage AB Detailed destructive examinations and microscopy documented the progression of fatigue damage, from crack initiation to crack link-up, in aluminum alloy 2024-T3 fuselage skin. The simultaneous presence of small fatigue cracks contained in hundreds of rivet holes resulted from fretting damage along the mating surface of the riveted lap joint. The formation of microcracks within the fretting region led to the development of small fatigue cracks that were undetected during the major portion of the full scale fuselage fatigue test (60,000 full pressure cycles). After initiation, the path of small fatigue cracks was influenced by local residual stresses produced by rivet expansion and out-of-plane loading. It was discovered that small cracks in the riveted fuselage skin exhibit similar fatigue crack growth characteristics; similar fatigue crack growth characteristics were observed for cracks (50 mu m to 10mm) emanating from counterbore rivets, straight shank rivets, and 100 degrees countersink rivets. FASTRAN code predictions show that the growth of fatigue damage in the fuselage lap joint structure can be predicted by fracture mechanics based methods. C1 NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. RP Piascik, RS (reprint author), NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-08-043011-2 PY 1999 BP 457 EP 464 DI 10.1016/B978-008043011-9/50042-9 PG 8 WC Engineering, Mechanical SC Engineering GA BP92Z UT WOS:000086647400041 ER PT S AU Peele, AG AF Peele, AG BE Brumby, SP TI Instrumentation for a next-generation x-ray all-sky monitor SO SMALL MISSIONS FOR ENERGETIC ASTROPHYSICS: ULTRAVIOLET TO GAMMA-RAY SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Small Missions for Energetic Astrophysics CY FEB, 1999 CL LOS ALMOS NATL LAB, J ROBERT OPPENHEIMER STUDY CTR, LOS ALAMOS, NM SP NASA, Los Alamos Natl Lab, Ctr Space Sci & Explorat, Los Alamos Natl Lab, Inst Geophys & Planetary Phys HO LOS ALMOS NATL LAB, J ROBERT OPPENHEIMER STUDY CTR ID CHANNEL-CAPILLARY ARRAYS; OPTICS AB We have proposed an a-ray all-sky monitor for a small satellite mission that will be ten times more sensitive than past monitors and that opens up a new band of the soft x-ray spectrum (0.1 - 3.0 keV) for study. We discuss three approaches to the construction of the optics. The first method, well within the reach of existing technology, is to approximate the lobster-eye geometry by building crossed arrays of planar reflectors, this gives Feat control over the reflecting surface but is limited in terms of resolution at the baseline 4 are minute level. The second method is to use microchannel plates; this technology has the potential to greatly exceed the baseline resolution and sensitivity but is yet to be fully demonstrated. The third method, while still in its infancy, may yet prove to be the most powerful, this approach relies on photolithography to expose a substrate that can then be developed and replicated. The scientific case for this mission is almost too broad to state here. The instrument we describe will allow investigation of the long term light curves of thousands of AGN, it will detect thousands of transients, including GRBs and type IT supernova, and the stellar coronae of hundreds of the brightest x-ray stars can be monitored. In addition the classical objectives of all-sky monitors - long-term all-shy archive and watchdog alert to new events - will be fulfilled at an unprecedented level. We also note that by opening up a little-explored band of the x-ray sky the opportunity for new discovery is presented. A satisfying example of entering new territory while still retaining the guarantee of expanding the domain of existing research. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Peele, AG (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-912-2 J9 AIP CONF PROC PY 1999 VL 499 BP 135 EP 145 DI 10.1063/1.1302229 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BP29E UT WOS:000084595200015 ER PT S AU Bar-Cohen, Y Leary, S Shahinpoor, M Harrison, JO Smith, J AF Bar-Cohen, Y Leary, S Shahinpoor, M Harrison, JO Smith, J BE BarCohen, Y TI Flexible low-mass devices and mechanisms actuated by Electroactive Polymers SO SMART STRUCTURES AND MATERIALS 1999: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE miniature robotics; electroactive polymers; hand simulation; EAP actuators; surface wiper; EAP gripper AB Miniature, lightweight, miser actuators that operate similar to biological muscles can be used to develop robotic devices with unmatched capabilities to impact many technology areas. Electroactive polymers (EAP) offer the potential to producing such actuators and their main attractive feature is their ability to induce relatively large bending or longitudinal strain. Generally, these materials produce a relatively low force and the applications that can be considered at the current state of the art are relatively limited. This reported study is concentrating on the development of effective EAPs and the resultant enabling mechanisms employing their unique characteristics. Several EAP driven mechanisms, which emulate human hand, were developed including a gripper, manipulator arm and surface wiper. The manipulator arm was made of a composite rod with an EAP actuator consisting of a scrolled rope that is activated longitudinally by an electrostatic field. A gripper was made to serve as an end effector and it consisted of multiple bending EAP fingers for grabbing and holding such objects as rocks. An EAP surface wiper was developed to operate like a human finger and to demonstrate the potential to remove dust from optical and LR windows as well as solar cells. These EAP driven devices are taking advantage of the large actuation displacement of these materials but there is need for a significantly greater actuation force capability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 41 Z9 41 U1 1 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3143-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3669 BP 51 EP 56 DI 10.1117/12.349697 PG 6 WC Automation & Control Systems; Engineering, Biomedical; Engineering, Mechanical; Materials Science, Ceramics; Optics; Polymer Science SC Automation & Control Systems; Engineering; Materials Science; Optics; Polymer Science GA BN29N UT WOS:000081456100007 ER PT S AU Bar-Cohen, Y Leary, S Shahinpoor, M Harrison, JO Smith, J AF Bar-Cohen, Y Leary, S Shahinpoor, M Harrison, JO Smith, J BE BarCohen, Y TI Electro-Active Polymer (EAP) actuators for planetary applications SO SMART STRUCTURES AND MATERIALS 1999: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE miniature robotics; electroactive polymers; electroactive actuators; EAP materials ID IONOMER MEMBRANES; NAFION MEMBRANES; WATER TRANSPORT AB NASA is seeking to reduce the mass, size, consumed power, and cost of the instrumentation used in its future missions. An important element of many instruments and devices is the actuation mechanism and electroactive polymers (EAP) are offering an effective alternative to current actuators. Ire this study, two families of EAP materials were investigated, including bending ionomers and longitudinal electrostatically driven elastomers. These materials were demonstrated to effectively actuate manipulation devices and their performance is being enhanced in this on-going study. The recent observations are reported in this paper, include the operation of the bending-EAP at conditions that exceed the harsh environment on Mars, and identify the obstacles that its properties and characteristics are posing to using them as actuators. Analysis of the electrical characteristics of the ionomer EAP showed that it is a current driven material rather than voltage driven and the conductivity distribution on the surface of the material greatly influences the bending performance. An accurate equivalent circuit modeling of the ionomer EAP performance is essential for the design of effective drive electronics. The ionomer main limitations are the fact that it needs to be moist continuously and the process of electrolysis that takes place during activation. An effective coating technique using a sprayed polymer was developed extending its operation in air from a few minutes to about four months. The coating technique effectively forms the equivalent of a skin to protect the moisture content of the ionomer. In parallel to the development of the bending EAP, the development of computer control of actuated longitudinal EAP has been pursued. An EAP driven miniature robotic arm was constructed and it is controlled by a MATLAB code to drop and lift the arm and close and open EAP fingers of a 4-finger gripper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 30 Z9 30 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3143-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3669 BP 57 EP 63 DI 10.1117/12.349708 PG 7 WC Automation & Control Systems; Engineering, Biomedical; Engineering, Mechanical; Materials Science, Ceramics; Optics; Polymer Science SC Automation & Control Systems; Engineering; Materials Science; Optics; Polymer Science GA BN29N UT WOS:000081456100008 ER PT S AU Leary, S Bar-Cohen, Y AF Leary, S Bar-Cohen, Y BE BarCohen, Y TI Electrical impedance of ionic polymeric metal composites SO SMART STRUCTURES AND MATERIALS 1999: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE IPMC; electroactive polymers (EAP); bending EAP; miniature actuators AB In recent years the use of ionic polymer metal composites such as Nafion-based platinum ionomers have emerged as electroactive polymer materials with great potential for robotics and other applications. An effective activation of these materials requires understanding of their mechanism of operation. Generally, the material needs to be maintained hydrated to assure its electromechanical activity. To allow the control of the response of the material, a study is underway to investigate the electrical response. Particular emphasis is placed on possible electrochemical reactions and deviations from linear dielectric behavior. Currently, efforts are made to determine the necessary drive characteristics of the source to allow low power operation (less than or equal to 1.0 W) of the material as an actuator. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Leary, S (reprint author), CALTECH, Jet Prop Lab, MS 82-105,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 10 Z9 10 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3143-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3669 BP 81 EP 86 DI 10.1117/12.349713 PG 6 WC Automation & Control Systems; Engineering, Biomedical; Engineering, Mechanical; Materials Science, Ceramics; Optics; Polymer Science SC Automation & Control Systems; Engineering; Materials Science; Optics; Polymer Science GA BN29N UT WOS:000081456100011 ER PT S AU Ounaies, Z Park, C Harrison, JS Smith, JG Hinkley, J AF Ounaies, Z Park, C Harrison, JS Smith, JG Hinkley, J BE BarCohen, Y TI Structure-property study of piezoelectricity in polyimides SO SMART STRUCTURES AND MATERIALS 1999: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE piezoelectric; polymer; polyimide; polarization AB High performance piezoelectric polymers are of interest to NASA as they may be useful for a variety of sensor applications. Over the past few years research on piezoelectric polymers has led to the development of promising high temperature piezoelectric responses in some novel polyimides. in this study, a series of polyimides have been studied with systematic variations in the diamine monomers which comprise the polyimide while holding the dianhydride constant. The effect of structural changes, including variations in the nature and concentration of dipolar groups, on the remanent polarization and piezoelectric coefficient is examined. Fundamental structure-piezoelectric property insight will enable the molecular design of polymers possessing distinct improvements over state-of-the-art piezoelectric polymers including enhanced polarization, polarization stability at elevated temperatures, and improved processability. C1 NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. RP Ounaies, Z (reprint author), NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. NR 5 TC 17 Z9 17 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3143-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3669 BP 171 EP 178 DI 10.1117/12.349674 PG 8 WC Automation & Control Systems; Engineering, Biomedical; Engineering, Mechanical; Materials Science, Ceramics; Optics; Polymer Science SC Automation & Control Systems; Engineering; Materials Science; Optics; Polymer Science GA BN29N UT WOS:000081456100020 ER PT S AU Sokolowski, WM Chmielewski, AB Hayashi, S Yamada, T AF Sokolowski, WM Chmielewski, AB Hayashi, S Yamada, T BE BarCohen, Y TI Cold hibernated elastic memory (CHEM) self-deployable structures SO SMART STRUCTURES AND MATERIALS 1999: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE expandable structures; shape memory polymers; open cellular structures; glass transition temperature Tg; glassy and rubbery states AB Experiments have confirmed the feasibility of an innovative, new class of very simple, reliable, low mass, low packaging volume, and low-cost self-deployable structures for space and commercial applications. The concept called "cold hibernated elastic memory" (CHEM) utilizes shape memory polymers (SMP) in open cellular (foam) structures. The SMP foam materials are under development by the Jet Propulsion Laboratory (JPL) and Mitsubishi Heavy Industries (MHI). The CHEM structures are described here and their major advantages are identified over other expandable/deployable structures. In preliminary proof-of-concept investigation conducted on SMP foams, all evaluation/test results were very encouraging and confirmed the basic characteristics of CHEM structures. The main objective of this program is to develop and validate the CHEM structure technology for most promising space applications. However, possible terrestrial commercial applications are also anticipated and described in this paper as well. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sokolowski, WM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 25 Z9 25 U1 1 U2 13 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3143-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3669 BP 179 EP 185 DI 10.1117/12.349675 PG 7 WC Automation & Control Systems; Engineering, Biomedical; Engineering, Mechanical; Materials Science, Ceramics; Optics; Polymer Science SC Automation & Control Systems; Engineering; Materials Science; Optics; Polymer Science GA BN29N UT WOS:000081456100021 ER PT S AU Brown, T Wood, K Childers, B Cano, R Jensen, B Rogowski, R AF Brown, T Wood, K Childers, B Cano, R Jensen, B Rogowski, R BE Jacobs, JH TI Fiber optic sensors for health monitoring of morphing aircraft SO SMART STRUCTURES AND MATERIALS 1999: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE fiber optic sensors; Bragg gratings; strain; chemical sensors; composites ID DISTRIBUTED MEASUREMENT AB Fiber optic sensors are being developed for health monitoring of future aircraft Aircraft health monitoring involves the use of strain, temperature, vibration and chemical sensors. These sensors will measure load and vibration signatures that will be used to infer structural integrity. Since the aircraft morphing program assumes that future aircraft will be aerodynamically reconfigurable there is also a requirement for pressure, flow and shape sensors. In some cases a single fiber may be used for measuring several different parameters. The objective of the current program is to develop techniques for using optical fibers to monitor composite cure in real time during manufacture and to monitor in-service structural integrity of the composite structure. Graphite-epoxy panels were fabricated with integrated optical fibers of various types. The panels were mechanically and thermally tested to evaluate composite strength and sensor durability. Finally the performance of the fiber optic sensors was determined Experimental results are presented evaluating the performance of embedded and surface mounted optical fibers for measuring strain, temperature and chemical composition. The performance of the fiber optic sensors was determined by direct comparison with results from more conventional instrumentation. The facilities for fabricating optical fiber and associated sensors and methods of demodulating Bragg gratings for strain measurement will be described. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Brown, T (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 3 TC 6 Z9 6 U1 1 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3148-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3674 BP 60 EP 71 DI 10.1117/12.351590 PG 12 WC Engineering, Aerospace; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BN39R UT WOS:000081784200007 ER PT S AU McGowan, AMR AF McGowan, AMR BE Jacobs, JH TI A feasibility study on using shunted piezoelectrics to reduce aeroelastic response SO SMART STRUCTURES AND MATERIALS 1999: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE shunted piezoelectric; damping augmentation; aeroservoelasticity; and aeroelastic load alleviation ID VIBRATION SUPPRESSION AB Several analytical and experimental studies clearly demonstrate that piezoelectric materials (piezoelectrics) can be used as actuators to actively control vibratory response, including aeroelastic response. However, two important issues in using piezoelectrics as actuators for active control are: 1) the potentially large amount of power required to operate the actuators, and 2) the complexities involved with active control (added hardware, control law design, and implementation). Active or passive damping augmentation using shunted piezoelectrics may provide a viable alternative. This approach requires only simple electrical circuitry and very little or no electrical power. The current study examines the feasibility of using shunted piezoelectrics to reduce aeroelastic response using a typical-section representation of a wing and piezoelectrics shunted with a parallel resistor and inductor. The aeroelastic analysis shows that shunted piezoelectrics can effectively reduce aeroelastic response below flutter and may provide a simple, low-power method of subcritical aeroelastic control. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP McGowan, AMR (reprint author), NASA, Langley Res Ctr, MS 340, Hampton, VA 23681 USA. NR 43 TC 1 Z9 1 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3148-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3674 BP 178 EP 195 DI 10.1117/12.351555 PG 18 WC Engineering, Aerospace; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BN39R UT WOS:000081784200018 ER PT S AU Bryant, RG Fox, RL Lachowicz, JT Chen, FJ AF Bryant, RG Fox, RL Lachowicz, JT Chen, FJ BE Jacobs, JH TI Piezoelectric synthetic jets for aircraft control surfaces SO SMART STRUCTURES AND MATERIALS 1999: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE piezoelectric; unimorph; bimorph; synthetic jet; vortex generators; actuators; multilayered actuators; prestressed actuators AB The concept of using piezoelectric actuators in devices that alter the way in which an airfoil interacts with its environment is not new. In fact, several notable research institutions, federal laboratories and industrial partners are actively pursuing this type of research. The main driving force for this activity is increased fuel economy, lighter aircraft and the elimination of hydraulically actuated control surfaces. Several years ago, researchers at NASA developed a process that uniformly prestressed the piezoelectric actuators resulting in increased movement at low frequencies. The key to this increased motion was the ability to develop an evenly prestressed actuator that behaved like a leaf spring. In order to take full advantage of this piezoelectric wafer, the fixturing and drive electronics had to be developed. This is a critical issue for all piezoelectric systems. This paper describes the characteristics and performances of these high displacement actuators and the devices that incorporate these actuators to create the synthetic jets. It is envisioned that these devices will play a critical role in the future of aeronautics. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bryant, RG (reprint author), NASA, Langley Res Ctr, MS 226, Hampton, VA 23681 USA. NR 14 TC 7 Z9 7 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3148-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3674 BP 220 EP 227 DI 10.1117/12.351560 PG 8 WC Engineering, Aerospace; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BN39R UT WOS:000081784200022 ER PT S AU Horner, G Taleghani, B AF Horner, G Taleghani, B BE Jacobs, JH TI Single axis piezoceramic gimbal SO SMART STRUCTURES AND MATERIALS 1999: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE actuator; gimbal; piezoceramic; scanner AB This paper describes the fabrication, testing, and analysis of a single axis piezoceramic gimbal. The fabrication process consists of pre-stressing a piezoceramic wafer using a high-temperature thermoplastic polyimide and a metal foil. The differential thermal expansion between the ceramic and metal induces a curvature. The pre-stressed, curved piezoceramic is mounted on a support mechanism and a minor is attached to the piezoceramic. A plot of gimbal angle versus applied voltage to the piezoceramic is presented. A finite element analysis of the piezoceramic gimbal is described. The predicted gimbal angle versus applied voltage is compared to experimental results. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Horner, G (reprint author), NASA, Langley Res Ctr, MS 230, Hampton, VA 23681 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3148-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3674 BP 371 EP 378 DI 10.1117/12.351574 PG 8 WC Engineering, Aerospace; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BN39R UT WOS:000081784200036 ER PT S AU Horner, GC Bromberg, L Teter, JP AF Horner, GC Bromberg, L Teter, JP BE Jacobs, JH TI A cryogenic magnetostrictive actuator using a persistent high temperature superconducting magnet, part 1: Concept, and design SO SMART STRUCTURES AND MATERIALS 1999: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE actuator; cryogenic; magnetostriction; NGST; optics; persistent; superconductor; Terzinol AB Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications, such as Next Generation Space Telescope (NGST), the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in I-ITS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Very fast charging and discharging of HTS tubes, as short as 100 microseconds, has been demonstrated. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSSCO 2212 with a magnetostrictive element will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Horner, GC (reprint author), NASA, Langley Res Ctr, MS 230, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3148-6 J9 P SOC PHOTO-OPT INS PY 1999 VL 3674 BP 499 EP 504 DI 10.1117/12.351559 PG 6 WC Engineering, Aerospace; Engineering, Mechanical; Mechanics; Optics SC Engineering; Mechanics; Optics GA BN39R UT WOS:000081784200049 ER PT S AU Lee, HJ Saravanos, DA AF Lee, HJ Saravanos, DA BE Varadan, VV TI A mixed multi-field finite element formulation for thermopiezoelectric composite shells SO SMART STRUCTURES AND MATERIALS 1999: MATHEMATICS AND CONTROL IN SMART STRUCTURES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE actuators; adaptive structures; composites; finite element method; piezoelectric; sensors; shells; smart materials; temperature ID INTELLIGENT STRUCTURES; PIEZOTHERMOELASTICITY AB Analytical formulations are presented which account for the coupled mechanical, electrical, and thermal response of piezoelectric composite shell structures. A new mixed multi-field laminate theory is developed which combines "single layer" assumptions for the displacements along with layerwise fields for the electric potential and temperature. This laminate theory is formulated using curvilinear coordinates and is based on the principles of linear thermopiezoelectricity. The mechanics has the inherent capability to explicitly model both the active and sensory responses of piezoelectric composite shells in thermal environments. Finite element equations are derived and implemented for an eight-noded shell element. Numerical studies are conducted to investigate both the sensory and active responses of piezoelectric composite shell structures subjected to thermal loads. Results for a cantilevered plate with an attached piezoelectric layer are compared with corresponding results from a commercial finite element code and a previously developed program. Additional studies are conducted on a cylindrical shelf with an attached piezoelectric layer to demonstrate capabilities to achieve thermal shape control on curved piezoelectric structures. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Lee, HJ (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,Mail Stop 49-8, Cleveland, OH 44135 USA. NR 15 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3141-9 J9 P SOC PHOTO-OPT INS PY 1999 VL 3667 BP 449 EP 460 DI 10.1117/12.350096 PG 4 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Mathematics, Applied; Mechanics; Optics SC Acoustics; Engineering; Mathematics; Mechanics; Optics GA BN32R UT WOS:000081632600042 ER PT S AU Das, H Bao, X Bar-Cohen, Y Bonitz, R Lindemann, R Maimone, M Nesnas, I Voorhees, C AF Das, H Bao, X Bar-Cohen, Y Bonitz, R Lindemann, R Maimone, M Nesnas, I Voorhees, C BE Wereley, NM TI Robot manipulator technologies for planetary exploration SO SMART STRUCTURES AND MATERIALS 1999: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE robot analysis; ultrasonic motors; rover-mounted manipulation; autonomous sample acquisition; autonomous instrument placement AB NASA exploration missions to Mars, initiated by the Mars Pathfinder mission in July 1997, will continue over the next decade. The missions require challenging innovations in robot design and improvements in autonomy to meet ambitious objectives under tight budget and time constraints. The authors are developing design tools, component technologies and capabilities to address these needs for manipulation with robots for planetary exploration. The specific developments are: 1) a software analysis tool to reduce robot design iteration cycles and optimize on design solutions, 2) new piezoelectric ultrasonic motors (USM) for light-weight and high torque actuation in planetary environments, 3) use of advanced materials and structures for strong and light-weight robot arms and 4) intelligent camera-image coordinated autonomous control of robot arms for instrument placement and sample acquisition from a rover vehicle. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Das, H (reprint author), CALTECH, Jet Prop Lab, MS 198-219, Pasadena, CA 91109 USA. NR 16 TC 3 Z9 4 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3142-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3668 BP 175 EP 182 DI 10.1117/12.350698 PG 8 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BN32S UT WOS:000081632900015 ER PT S AU Dekens, FG Neat, G AF Dekens, FG Neat, G BE Wereley, NM TI Micro-Precision Interferometer: Pointing system performance in on-orbit disturbance environment. SO SMART STRUCTURES AND MATERIALS 1999: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE space interferometry; isolation system; interferometry testbed AB We investigate how the Space Interferometer Mission (SIM) will be able to meet its instrument astrometric: pointing requirements. The most demanding SIM pointing requirement is to independently point each interferometer arm to better than 0.07 micro-radian RMS residual jitter using a 0.01 Hz bandwidth optical sensor. The predominant contributors to the pointing error are the spinning spacecraft reaction wheel assemblies which emit; disturbances from 2 Hz to 1 kHz. An estimate of the residual pointing error is presented for this most challenging vibration attenuation problem which is with isolated reaction wheels with no optical compensation. Central to this estimate is the Micro-Precision Interferometer (MPI) testbed which is a softly suspended hardware model of a future space-borne optical interferometer and is dimensionally representative of SIM. The prediction of the on-orbit pointing error is determined in part by measuring broadband disturbance transfer functions from the testbed's isolated reaction wheel location to the camera output, where the pointing must be stabilized; Off-line, the procedure combines the measured testbed transfer functions with an empirical model of the reaction wheel disturbance to determine jitter over the entire range of wheel speeds. Results suggest that the most demanding SIM pointing requirement is currently violated by a factor of ten. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dekens, FG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3142-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3668 BP 426 EP 439 DI 10.1117/12.350691 PG 14 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BN32S UT WOS:000081632900038 ER PT S AU Taleghani, BK Campbell, JF AF Taleghani, BK Campbell, JF BE Wereley, NM TI Non-linear finite element modeling of THUNDER piezoelectric actuators SO SMART STRUCTURES AND MATERIALS 1999: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE NASTRAN; finite element; non-linear; THUNDER; piezoelectric; actuator AB A NASTRAN non-linear finite element model has been developed for predicting the dome heights of THUNDER (THin Layer UNimorph Ferroelectric DrivER) piezoelectric actuators. To analytically validate the finite element model, a comparison was made with a non-linear plate solution using Von Karmen's approximation. A 500 volt input was used to examine the actuator deformation. The NASTRAN finite element model was also compared with experimental results. Four groups of specimens were fabricated and tested. Four different input voltages, which included 120, 160, 200, and 240 Vp-p with a 0 volts offset, were used for this comparison. C1 NASA, Langley Res Ctr, Vehicle Technol Ctr, Army Res Lab, Hampton, VA 23681 USA. RP Taleghani, BK (reprint author), NASA, Langley Res Ctr, Vehicle Technol Ctr, Army Res Lab, MS 230, Hampton, VA 23681 USA. NR 5 TC 19 Z9 20 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3142-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3668 BP 555 EP 566 DI 10.1117/12.350733 PG 12 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BN32S UT WOS:000081632900049 ER PT S AU Bar-Cohen, Y Bao, XQ Grandia, W AF Bar-Cohen, Y Bao, XQ Grandia, W BE Wereley, NM TI Rotary ultrasonic motors actuated by traveling flexural waves SO SMART STRUCTURES AND MATERIALS 1999: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE Proceedings of SPIE LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE piezoelectric motors; ultrasonic motors (USMs); stators and rotors; modal analysis; actuators; active materials AB Efficient miniature actuators that are compact and consume low power are needed to drive space and planetary mechanisms in future NASA missions. Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors have emerged in commercial products but they need to be adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and also require effective analytical tools for the design of efficient motors. A finite element analytical model was developed to examine the excitation of flexural plate wave traveling in a piezoelectrically actuated rotary motor. The model uses 3D finite element and equivalent circuit models that are applied to predict the excitation frequency and modal response of the stator. This model incorporates the details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. The theoretical predictions were corroborated experimentally for the stator. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. Experiments have shown that the motor can sustain at:least 230 temperature cycles from 0 degrees C to -90 degrees C at 7 Torr pressure significant performance change. Also, in an earlier study the motor lasted over 334 hours at -150 degrees C and vacuum. To explore telerobotic applications for USMs a robotic arm was constructed with such motors. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM yosi@jpl.nasa.gov NR 8 TC 2 Z9 3 U1 3 U2 8 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3142-7 J9 PROC SPIE PY 1999 VL 3668 BP 698 EP 704 DI 10.1117/12.350745 PG 7 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BN32S UT WOS:000081632900061 ER PT S AU Choi, SH Chu, SH Kwak, M Cutler, AD AF Choi, SH Chu, SH Kwak, M Cutler, AD BE Wereley, NM TI A study on a microwave-driven smart material actuator SO SMART STRUCTURES AND MATERIALS 1999: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 1999 Conference CY MAR 01-04, 1999 CL NEWPORT BEACH, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp, Def Adv Res Projects Agcy, US Army Res Off, USAF Res Lab, Ceram Soc Japan, Intelligent Mat Forum, Japan DE microwave; actuator; piezoelectric; rectenna ID SURFACE; ANTENNA; POWER AB NASA's Next Generation Space Telescope (NGST) has a large deployable, fragmented optical surface (greater than or equal to 8 m in diameter) that requires autonomous correction of deployment misalignments and thermal effects. Its high and stringent resolution requirement imposes a great deal of challenge for optical correction. The threshold value for optical correction is dictated by lambda/20 (30 nm for NGST optics). Control of an adaptive optics array consisting of a large number of optical elements and smart material actuators is so complex that power distribution for activation and control of actuators must be done by other than hard-wired circuitry. The concept of microwave-driven smart actuators is envisioned as the best option to alleviate the complexity associated with hard-wiring. A microwave-driven actuator was studied to realize such a concept for future applications. Piezoelectric material was used as an actuator that shows dimensional change with high electric field. The actuators were coupled with microwave rectenna and tested to correlate the coupling effect of electromagnetic wave. In experiments, a 3x3 rectenna patch array generated more than 50 volts which is a threshold voltage for 30-nm displacement of a single piezoelectric material. Overall, the test results indicate that the microwave-driven actuator concept can be adopted for NGST applications. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Choi, SH (reprint author), NASA, Langley Res Ctr, MS 188B, Hampton, VA 23681 USA. NR 22 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3142-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3668 BP 853 EP 863 DI 10.1117/12.350762 PG 11 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BN32S UT WOS:000081632900076 ER PT J AU Ahn, CW Baumgardner, MF Biehl, LL AF Ahn, CW Baumgardner, MF Biehl, LL TI Delineation of soil variability using geostatistics and fuzzy clustering analyses of hyperspectral data SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID OPTIMAL INTERPOLATION; C-MEANS; LAND EVALUATION; CLASSIFICATION; ALGORITHM AB A soil map is one of the key data layers for developing a robust global model and evaluating land quality and use. A current soil map produced by conventional soil survey is the major source of soil information. However, such a map may not pro,ide the desired accuracy in terms of scale and cartographic quality as a digital format for geographic information system (GIS) modeling applications. This stud!, was designed to introduce and test the procedures for improving the objectivity and accuracy in the delineation of soil patterns with the use of hyperspectral imagery. These hyperspectral data were analyzed through different models including the linear mixture model, blockkriging interpolation, and fuzzy-c-means (FCM) algorithms, Hyperspectral remote sensing data, having very good spectral and spatial resolution, were used for quantifying soil patterns and conditions, A linear spectral mixing model was effectively used not only for reducing dimensionality but also for removing vegetation effects for studying soil patterns from a single soil map layer derived from hyperspectral remote sensing data. Block kriging interpolation based on a semivariogram fitted with the isotropic exponential model represented soil patterns very well beyond the limitation of the size of pixel. Fuzzy-c-means clustering analysis showed clear membership patterns and segmented soil patterns effectively, although this is not a soil map in the conventional sense. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Biospher Sci Branch, Greenbelt, MD 20771 USA. Purdue Univ, Dept Agron, W Lafayette, IN 47907 USA. Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. RP Baumgardner, MF (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. NR 33 TC 25 Z9 31 U1 0 U2 13 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 JAN-FEB PY 1999 VL 63 IS 1 BP 142 EP 150 PG 9 WC Soil Science SC Agriculture GA 179ZE UT WOS:000079359600020 ER PT B AU Andretta, V Kucera, TA Poland, AI AF Andretta, V Kucera, TA Poland, AI BE Butler, CJ Doyle, JG TI Observations of hydrogen and helium continua in solar prominences SO SOLAR AND STELLAR ACTIVITY: SIMILARITIES AND DIFFERENCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Solar and Stellar Activity - Similarities and Differences CY SEP 02-04, 1998 CL ARMAGH, NORTH IRELAND ID SOHO MISSION AB Observations in the Extreme Ultraviolet of solar prominences provide new and potentially very interesting diagnostics for the density and ionization state of prominences. In this paper we show some examples and preliminary results. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Andretta, V (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Kucera, Therese/C-9558-2012 NR 5 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-78-3 J9 ASTR SOC P PY 1999 VL 158 BP 162 EP 165 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM90U UT WOS:000080088500017 ER PT J AU Hagyard, MJ Stark, BA Venkatakrishnan, P AF Hagyard, MJ Stark, BA Venkatakrishnan, P TI A search for vector magnetic field variations associated with the M-class flares of 10 June 1991 in AR 6659 SO SOLAR PHYSICS LA English DT Article ID SHEAR AB A careful analysis of a 6-hour time sequence of vector magnetograms of AR 6659, observed on 10 June 1991 with the MSFC vector magnetograph, has revealed only minor changes in the vector magnetic field azimuths in the vicinity of two M-class flares, and the association of these changes with the flares is not unambiguous. In this paper we present our analysis of the data which includes comparison of vector magnetograms prior to and during the flares, calculation of distributions of the r.m.s. variation of the azimuth at each pixel in the field of view of the active region, and examination of the variation with time of the azimuths along the flaring neutral lines and at every pixel covered by the main flare emissions as observed with the H alpha telescope coaligned with the vector magnetograph. C1 NASA, Space Sci Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Nichols Res, Huntsville, AL USA. Indian Inst Astrophys, Bangalore 560034, Karnataka, India. RP Hagyard, MJ (reprint author), NASA, Space Sci Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 9 TC 40 Z9 40 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1999 VL 184 IS 1 BP 133 EP 147 DI 10.1023/A:1005072625659 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172UV UT WOS:000078944000008 ER PT J AU Batchelor, D AF Batchelor, D TI X-ray observations of recurrence of eruptive flares and active regions SO SOLAR PHYSICS LA English DT Article ID MAGNETIC-FLUX; SUN AB In a study of soft X-ray coronal images obtained with the Yohkoh spacecraft, two eruptive flares with remarkably similar X-ray structures were noted - most remarkably because the flares occurred at the same solar location (approximately 10 deg north latitude on the east limb) yet separated in time by three solar rotations. Between the times of the eruptions, the active region responsible for the first flare disappeared from Yohkoh images. An extremely similar X-ray active region replaced it by the third solar rotation. The recurring X-ray active region appearance and recurring flare activity after 86 days suggest that persistent subsurface flux emergence patterns might be responsible, and support previous arguments that 'active longitudes' exist. C1 NASA, Sci Commun Technol Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Batchelor, D (reprint author), NASA, Sci Commun Technol Branch, Goddard Space Flight Ctr, Mail Code 933, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1999 VL 184 IS 1 BP 149 EP 152 DI 10.1023/A:1005084306791 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172UV UT WOS:000078944000009 ER PT J AU Janardhan, P Bird, MK Edenhofen, P Wohlmuth, R Plettemeier, D Asmar, SW Patzold, M Karl, J AF Janardhan, P Bird, MK Edenhofen, P Wohlmuth, R Plettemeier, D Asmar, SW Patzold, M Karl, J TI Coronal velocity measurements with Ulysses: Multi-link correlation studies during two superior conjunctions SO SOLAR PHYSICS LA English DT Article ID SOLAR-WIND VELOCITY; ELECTRON-DENSITY; RANGING MEASUREMENTS; 1995 CONJUNCTION; SPACECRAFT; SCINTILLATION; FLUCTUATIONS; SCATTERING; PLASMA; SPEED AB A well-known method for studying the solar wind very close to the Sun (heliocentric distances: 4 to 40 solar radii) is by radio sounding between a spacecraft at superior conjunction and the Earth. The Ulysses Solar Corona Experiment was performed at the spacecraft's two solar conjunctions in summer 1991 and winter 1995, during which dual-frequency ranging and Doppler observations were conducted globally on a nearly continuous basis at the NASA Deep Space Network and other ground stations. The dual-frequency Doppler measurements were used to determine coronal plasma velocities by a cross-correlation analysis during those occasions when tracking data were recorded simultaneously at two well-separated ground stations. A 'filtering' technique was developed to suppress noise and enhance the 2-station correlations, a procedure particularly effective at small solar offsets. From the electron content measurements during the two solar conjunctions it was found that regions of higher electron density tend to occur when the two-station correlations yield slower outward flow velocities. C1 Inst Radioastron, D-53121 Bonn, Germany. Ruhr Univ Bochum, Inst HF Tech, D-44780 Bochum, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cologne, Inst Geophys, D-50923 Cologne, Germany. RP Janardhan, P (reprint author), Inst Radioastron, Hugel 71, D-53121 Bonn, Germany. NR 31 TC 13 Z9 15 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 JAN PY 1999 VL 184 IS 1 BP 157 EP 172 DI 10.1023/A:1005097028501 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 172UV UT WOS:000078944000011 ER PT S AU Woo, R Habbal, SR AF Woo, R Habbal, SR BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI A new view of the origin of the solar wind SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID PHYSICAL-PROPERTIES; CORONAL STREAMERS; SCALE STRUCTURES; LATITUDE; ULYSSES; SLOW; SCINTILLATION; MINIMUM; HOLE AB This paper uses white-light measurements made by the SOHO LASCO coronagraph and HAO Mauna Loa Mk III K-coronameter to illustrate the new view of solar wind structure deduced originally from radio occultation measurements. It is shown that the density profile closest to the Sun at 1.15 Ro, representing the imprint of the Sun, is carried essentially radially into interplanetary space by small-scale raylike structures that permeate the solar corona and which have only been observed by radio occultation measurements. The only exception is the small volume of interplanetary space occupied by the heliospheric plasma sheet that evolves from coronal streamers within a few solar radii of the Sun. The radial preservation of the density profile also implies that a significant fraction of field lines which extend into interplanetary space originate from the quiet Sun, and are indistinguishable in character from those emanating from polar coronal holes. The white-light measurements dispel the long-held belief that the boundaries of polar coronal holes diverge significantly, and further support the view originally proposed in (I) that the fast solar wind originates from the quiet Sun as well as polar coronal holes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Woo, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 30 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 71 EP 76 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700011 ER PT S AU Cane, HV Wibberenz, G Richardson, IG AF Cane, HV Wibberenz, G Richardson, IG BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Solar magnetic field variations and cosmic ray modulation SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID DECREASES; VOYAGER-1; HELIOSPHERE; STRENGTH AB Current modeling of long-term (Il-year) cosmic ray modulation incorporates as a major component the so-called "Global Merged interaction Regions" (GMIRs). GMIRs are assumed to be formed beyond about 10 AU by the merging of systems of coronal mass ejections (CMEs) and existing interaction regions. Merged interaction regions are identified from outer heliospheric magnetic field observations as complex structures and enhancements above the average field strength. We demonstrate that the similar to 1 year cosmic ray modulation events supposedly caused by GMIRs are already apparent at 1 AU, with the effects of individual major CMEs superimposed. Thus, GMTRs are unlikely to be the prime cause of long-term cosmic ray modulation. We show that the cosmic ray intensity is anti-correlated with the interplanetary magnetic field strength (IMF). The IMF shows an overall solar-cycle variation of about a factor of 2 together with episodic increases with durations of about a year which do not form in the interplanetary medium but are related to global variations of the solar photospheric magnetic field. We point out, once again, that cosmic rays are important probes of the structure of the interplanetary medium. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Cane, HV (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 15 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 99 EP 102 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700016 ER PT S AU Roberts, DA Goldstein, ML Deane, A Ghosh, S AF Roberts, DA Goldstein, ML Deane, A Ghosh, S BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI "Slab" modes, quasi-2-D turbulence, shear, and flux tubes in the expanding solar wind SO SOLAR WIND NINE SE AIP Conference Proceedings LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID CORRECTED TRANSPORT; ALFVEN WAVES; FLUCTUATIONS; EVOLUTION; REGION AB Solar wind fluctuations exhibit anisotropies in both the variances of the vectors and in power spectra. The latter have only been studied observationally in two dimensions, but the result is that there seems to be a preference for power along and transverse to the mean magnetic field, with significant but lower power in between. This observation has led to the idea that the solar wind turbulence consists of two main populations, "slab-like" parallel propagating Alfven waves and "quasi-2-D" fluctuations that have both wave vectors and fluctuations confined to a plane perpendicular to the mean field. Recent simulation studies suggest that the perpendicular component of the fluctuations may be due to the shearing of the slab modes, rather than to quasi-2-D fluctuations. Here we examine these scenarios and combinations of them using a compressible three-dimensional MHD code in spherical coordinates. Results show how nearly two-dimensional magnetohydrodynamic turbulence can be initiated and how it evolves with distance in the third dimension. Expanding flows lead to a suppression of the nonlinear cascades, mainly due to the changing transverse length scales. Quasi-2-D velocity fluctuation levels are determined more from the 2-D dynamics than from the expansion except when the velocity fluctuations are initially dominant. With expansion, quasi-2-D magnetic fluctuations always dominate the corresponding velocity fluctuations at late times. The "slab" modes produce perpendicular fluctuations when sheared, as in nonexpanding simulations, and these become dominant when initially equipartitioned with the quasi-2-D modes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 962, Greenbelt, MD 20771 USA. EM roberts@vayu.gsfc.nasa.gov; Melvyn.Goldstein@gsfc.nasa.gov; ron.ghosh@gsfc.nasa.gov RI Goldstein, Melvyn/B-1724-2008 NR 16 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 161 EP 166 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700027 ER PT S AU Buti, B Nocera, L AF Buti, B Nocera, L BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Chaotic Alfven waves in the solar wind SO SOLAR WIND NINE SE AIP Conference Proceedings LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID PLASMAS; TURBULENCE; EVOLUTION; SYSTEMS AB Spatio-temporal evolution, of large-amplitude Alfven waves driven by a harmonic driver, shows some very interesting and intriguing features like self-organization, collapse, turbulence and chaos. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buti, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bbuti@jplsp.jpl.nasa.gov OI /0000-0003-4147-6681 NR 23 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 173 EP 179 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700029 ER PT S AU Suess, ST Gary, GA Nerney, SF AF Suess, ST Gary, GA Nerney, SF BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI beta in Streamers SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID SOLAR CORONA AB The ratio of thermal pressure to magnetic pressure (beta) is greater than unity above similar to 1.2 R-S in streamers. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Suess, ST (reprint author), NASA, George C Marshall Space Flight Ctr, ES82, Huntsville, AL 35812 USA. NR 12 TC 13 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 247 EP 250 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700043 ER PT S AU Gopalswamy, N Shibasaki, K Thompson, BJ Gurman, JB DeForest, CE AF Gopalswamy, N Shibasaki, K Thompson, BJ Gurman, JB DeForest, CE BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Is the chromosphere hotter in coronal holes? SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID POLAR-CAP; REGION; SUN AB Coronal holes are brighter than the quiet Sun in microwaves. Microwave emission from the quiet Sun is optically thick thermal bremsstrahlung from the upper chromosphere. Therefore, the optically thick layer in the coronal hole chromosphere must be hotter than the corresponding layer in the quiet chromosphere. We present microwave and SOHO observations in support of this idea. Because of the availability of simultaneous EUV and microwave images it is now possible to obtain more details of this enigmatic phenomenon. In this paper, we highlight the primary properties of the microwave enhancement in coronal holes and point out some related phenomena. Finally, we summarize the possible explanations of the radio enhancement. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012; Thompson, Barbara/C-9429-2012 NR 15 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 277 EP 280 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700051 ER PT S AU Ruzmaikin, A Berger, MA AF Ruzmaikin, A Berger, MA BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI On generation of high-frequency Alfven waves in the solar corona SO SOLAR WIND NINE SE AIP Conference Proceedings LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID CROSSING NUMBER; MAGNETIC-FIELDS; ENERGY-SPECTRUM; WIND; NETWORK; FLUX AB We discuss a source for high-frequency Alfven waves, associated with twisted magnetic loops emerging on the solar surface and reconnecting with the open field. We identify the loops with the ephemeral regions (small-scale bipoles) observed by ground-based instruments and by SOHO. To characterize the loops we employ the concept of a minimum energy state for topologically complex fields. Our estimates of the power that can be released and the range of wave frequencies marginally agree with models of coronal heating and acceleration of the solar wind by high-frequency Alfven waves. We suggest that severe requirements on the upper-bound frequency, used in these models, can be relaxed by taking into account the energy released due to reconnections within magnetic loops whose footpoints are twisted by surface convective motions. This presentation updates our more extended discussion of the source of coronal heating (1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM aruzmaikin@jplsp.jpl.nasa.gov NR 19 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 325 EP 328 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700063 ER PT S AU Sittler, E Guhathakurta, M AF Sittler, E Guhathakurta, M BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Empirical model of the corona-solar wind with multiple current sheets SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID DISRUPTION; STREAMER AB We have developed a 2D semi-empirical MHD model of the solar corona and solar wind. The model uses empirically derived electron density profiles from white light coronagraph data measured by SOHO and empirically derived model of the magnetic field which is fit to observed streamer topologies which also come from white light coronagraph data. The model requires an estimate of solar wind velocity as a function of latitude at 1 AU and radial component of the magnetic field at 1 AU for which we use Ulysses plasma and magnetic field data results. The model makes estimates as functions of radial distance and latitude of various fluid parameters such as flow velocity V, effective temperature T-eff and effective heat flux q(eff) which are derived from conservation equations of mass, momentum and energy in the rotating frame of the Sun. The term effective indicates possible wave contributions. The model is a steady state calculation that assumes azimuthal symmetry. The magnetic field model shows that the large scale surface magnetic field is dominated by an octupole term. Initial attempts assumed the presence of a single current sheet which appears to be topologically incompatible with an internal field dominated by an octupole term. These earlier attempts had problems modeling the plasma and magnetic field near the Sun close to the equatorial plane. Therefore, for this study we have investigated the possible presence of multiple current sheets near the Sun for which initial results indicate that most of the problems with the magnetic field are corrected. For this paper we will present the results of this latest study. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sittler, E (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 14 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 401 EP 404 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700082 ER PT S AU Ofman, L Davila, JM AF Ofman, L Davila, JM BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Two-fluid 2,5D MHD model of the fast solar wind and the effective proton temperature SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID SOLITARY WAVES; ACCELERATION AB Recent SOHO/UVCS observations indicate that the perpendicular proton and ion temperatures are much larger than electron temperatures (Kohl et al 1997). In the present study we simulate numerically the solar wind flow in a coronal hole with the two-fluid approach. For simplicity, we neglect electron inertia. We investigate the effects of electron and proton temperatures on the solar wind acceleration by nonlinear waves. In the model the nonlinear waves are generated by Alfven waves with frequencies in the 10(-3) Hz range, driven at the base of the coronal hole. The resulting electron and proton how profile exhibits density and velocity fluctuations. The fluctuations may steepen into shocks as they propagate away from the sun. We construct the proton velocity distribution and a synthetic Ly-alpha line profile by including the combined effects of temperature and velocity fluctuations in the model, and compare them to the UVCS observations. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Ofman, L (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 682, Greenbelt, MD 20771 USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 405 EP 408 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700083 ER PT S AU Parhi, S Suess, ST Sulkanen, M AF Parhi, S Suess, ST Sulkanen, M BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI The generation of smooth high speed solar wind from plume-interplume mixing SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys AB We study the velocity shear which has been reported to exist between plumes and the interplume flow in coronal holes. The shear between two uniformly, magnetized regions can be unstable and evolve into a new less sheared pattern. We model fine scale velocity structures associated with the Kelvin-Helmholtz instability. We believe these fine structures could be part of the process of mixing of plume with interplume flow. When carried further downstream, the resultant momentum exchange may eliminate the sheer and lead to the observed smooth high speed wind. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Parhi, S (reprint author), NASA, Marshall Space Flight Ctr, Mail Stop ES 82, Huntsville, AL 35812 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 433 EP 435 PG 3 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700089 ER PT S AU Velli, M Buti, B Goldstein, BE Grappin, R AF Velli, M Buti, B Goldstein, BE Grappin, R BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Propagation and disruption of Alfvenic solitons in the expanding solar wind SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys AB The evolution of large amplitude circularly polarized Alfven solitons in the solar wind is described via dispersive MHD simulations in the expanding box model. Solar wind expansion causes the soliton amplitude to decay, initially following the standard WKB law, which together with the plasma cooling causes the propagation speed to decrease as well. At long times, the soliton disrupts, giving rise to relative density fluctuations which are enhanced as compared to those which develop when evolution is within the framework of homogeneous MHD. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Velli, M (reprint author), CALTECH, Jet Prop Lab, Ms 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 445 EP 448 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700092 ER PT S AU Liewer, PC Velli, M Goldstein, BE AF Liewer, PC Velli, M Goldstein, BE BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Hybrid simulations of wave propagation and ion cyclotron heating in the expanding solar wind SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID ACCELERATION; DISPERSION AB We present results from hybrid (particle ions, fluid electrons) simulations of the evolution of Alfven waves close to the ion cyclotron frequency in the solar wind, which take into account the basic properties of the background solar wind flow, i.e., the spherical expansion and the consequent decrease in magnetic field and cyclotron frequency with increasing distance from the Sun. We follow the evolution of a plasma parcel in a frame of reference moving with the solar wind using a 1D expanding box hybrid model; use of the hybrid model yields a fully self-consistent treatment of the resonant cyclotron wave-particle interaction. This model is related to a previous MHD model (1), which allows the use of a simple Cartesian geometry with periodic boundary conditions. The use of stretched expanding coordinates in directions transverse to the mean radial solar wind flow naturally introduces an anisotropic damping effect on velocity and magnetic field. We present results for the evolution of a 1/k spectrum of circularly polarized Alfven wave propagating radially. Initially, most of the wave energy is below the cyclotron frequency for both the alpha particles and protons. As the wind expands, the wave frequencies decrease more slowly than the cyclotron frequencies and the waves come into cyclotron resonance. When only protons are present, significant perpendicular heating is observed as the dominant wave frequencies approach the proton cyclotron frequency. When both alphas and protons are present, the alphas, which come into resonance first, are observed to be preferentially heated and accelerated. In both cases, the cyclotron damping leads to a steepening of the wave spectrum. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liewer, PC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 449 EP 452 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700093 ER PT S AU Goldstein, ML Roberts, DA Deane, A Ghosh, S Wong, HK AF Goldstein, ML Roberts, DA Deane, A Ghosh, S Wong, HK BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Numerical simulation of Alfvenic turbulence in the solar wind SO SOLAR WIND NINE SE AIP Conference Proceedings LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID FLUX-CORRECTED TRANSPORT; EVOLUTION; FLUCTUATIONS; WAVES AB We demonstrate that in an expanding volume, velocity shears and pressure-balanced flux tubes reduce the Alfvenicity of parallel propagating wave packets, as had been found previously in Cartesian geometry. The resulting power spectra have an inertial range spectral index of approximately 5/3. These three-dimensional spherically expanding simulations can include velocity shears separating fast and slow flows, pressure-balanced flux tubes, and a central current sheet. Two-dimensional spectra constructed in the r - theta plane resemble closely those resulting from similar initial conditions in Cartesian geometry. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. RI Goldstein, Melvyn/B-1724-2008 NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 535 EP 538 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700115 ER PT S AU Szabo, A Larson, DE Lepping, RP AF Szabo, A Larson, DE Lepping, RP BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI The heliospheric current sheet on small scale SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID INTERPLANETARY MAGNETIC-FIELD; PLANETARY SECTOR BOUNDARIES; ELECTRONS; PLASMA; CLOUD AB The heliospheric current sheet (HCS), the largest coherent structure in the heliosphere, is a wavy surface separating the two opposite magnetic polarity hemispheres of the heliosphere. Joint WIND magnetic field and electron observations near solar minimum conditions and far away from the Earth's bow shock reveal that while sector boundary crossings are usually marked by many, up to dozens of large field directional discontinuities, in most cases only one of them is a true sector polarity reversal and hence, a bona fide crossing of the global HCS. Though a number of multiple HCS crossings were identified along with magnetic cloud occlusions, most observations during our analysis interval are consistent with a single HCS surface with significant magnetic field kinks nearby it. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Szabo, A (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 21 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 589 EP 592 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700128 ER PT S AU Gopalswamy, N Kaiser, ML MacDowall, RJ Reiner, MJ Thompson, BJ Cyr, OCS AF Gopalswamy, N Kaiser, ML MacDowall, RJ Reiner, MJ Thompson, BJ Cyr, OCS BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Dynamical phenomena associated with a coronal mass ejection SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID PROMINENCE ERUPTION; SOLAR-FLARE AB The flare-CME-shock relationship has been controversial for more than two decades. This issue was traditionally addressed using white light coronagraphic data on CMEs, II-alpha or GOES data on hares and radio spectrographic data on shocks (inferred from metric type II radio bursts). A wealth of new information has become available after the advent of Yohkoh, SOHO and WIND missions that can be used to address the dynamical phenomena associated with CMEs. We present multiwavelength observations of the 1998 April 27 CME associated with coronal dimming, an X-class flare and type II radio bursts. We find that the coronal dimming observed in X-rays and EUV is indeed a CME signature and that the CME clearly precedes the accompanying flare. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012; Gopalswamy, Nat/D-3659-2012; Thompson, Barbara/C-9429-2012 NR 12 TC 16 Z9 16 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 641 EP 644 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700141 ER PT S AU Richardson, IG Cane, HV Cyr, OCS AF Richardson, IG Cane, HV Cyr, OCS BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Relationships between coronal and interplanetary structures inferred from energetic particle observations SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID SOLAR-WIND; DECREASES; HELIOS-1; EJECTA AB In recent studies, we have pointed out that the characteristic energetic particle signatures of interplanetary shocks, ejecta and corotating streams can be used to infer the presence of these structures even when in-situ solar wind observations are not available. The detailed solar observations currently available provide a test of this method. Using observations in 1996-97, me find that most (similar to 80%) of the earthward-directed CMEs observed by the SOHO/LASCO coronagraph produced signatures in the energetic particle data. We also note that, considering all the CMEs observed by LASCO, those associated with energetic (> 20 MeV) particle events were accompanied by the "traditional" signatures of energetic solar events such as type II and IV radio emissions, and Ha, and X-ray flares. They also had higher than average speeds and angular widths in the coronagaph observations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Richardson, IG (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 11 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 677 EP 680 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700150 ER PT S AU Osherovich, VA Fainberg, J Stone, RG Vinas, A Fitzenreiter, R Farrugia, CJ AF Osherovich, VA Fainberg, J Stone, RG Vinas, A Fitzenreiter, R Farrugia, CJ BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI MHD of gas with polytropic index below unity and classification of magnetic clouds SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID NONLINEAR EVOLUTION; FLUX ROPES; LOOP AB The self-similar magnetic cloud model of Osherovich, Farrugia and Burlaga (1, 2) is based on the exact class of MHD solutions for a magnetic flux rope with polytropic index gamma below unity. The problem in this model is reduced to a second order dynamic equation for the nonlinear oscillator The corresponding effective potential for the case gamma > 1 has only an oscillating mode and the case for gamma < 1 may have two modes: oscillatory and expansion. This model suggests three classes of magnetic clouds with different evolutionary patterns. For the first class (those which cannot overcome the threshold), the profile of the magnetic cloud is rather flat at I AU, and the velocity of expansion is small or even shows signs of contraction. The second class (those which have energy sufficient to overcome the threshold) is well described by a free expanding flux tube. The third class has a potential without a well suggesting expansion for all energies. The non-Maxwellian electron distribution function in a cloud explains the origin of the gamma < I thermodynamics (3, 4). A few polytropes observed in the same cloud suggest a number of magnetic tubes (4, 5). To classify complex clouds, we put forward a multi-tube model based on MHD bound-state solutions (6). This model presents clouds as multiple helices embedded in a cylindrical flux rope. C1 NASA, Goddard Space Flight Ctr, Raytheon STX, Greenbelt, MD 20771 USA. RP Osherovich, VA (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX, Code 690-2, Greenbelt, MD 20771 USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 717 EP 720 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700160 ER PT S AU Osherovich, VA Fainberg, J Fisher, RR Gibson, SE Goldstein, ML Guhathakurta, M Siregar, E AF Osherovich, VA Fainberg, J Fisher, RR Gibson, SE Goldstein, ML Guhathakurta, M Siregar, E BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI The north-south coronal asymmetry with inferred magnetic quadrupole SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID SOLAR CORONA; THEORETICAL-MODEL; SUNSPOT MINIMUM; APPROXIMATION AB The quiet corona at times close to solar minimum shows a striking north-south asymmetry which suggests that neither dipole-like nor octupole-like fields are sufficient to describe the global coronal magnetic field. We believe that such phenomena reflect the asymmetry of the intrinsic magnetic held of the sun as a star; this weak field is usually obscured by active regions. Empirical models for spherical corona (at solar maximum) and for ellipsoidal corona (at solar minimum) have been established. We extend the existing classification to include an empirical model for the quiet solar corona with strong north-south asymmetry. We show examples of such asymmetric corona in the green line for three different solar minima and evolution of corona from almost ellipsoidal type to corona with strong north-south asymmetry "bald man with double beard"). A theoretical model (1984) of Osherovich et al. (1) relates such asymmetry to the existence of a significant quadrupole term in the global magnetic field of the sun. According to this model, the size of northern and southern polar coronal holes is affected differently by a quadrupole term which creates asymmetry in the magnetic and thermodynamic parameters as well as in the velocity of the outflow from the two polar regions. RP Osherovich, VA (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX, Code 690-2, Greenbelt, MD 20771 USA. RI Goldstein, Melvyn/B-1724-2008 NR 17 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 721 EP 724 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700161 ER PT S AU Gazis, PR AF Gazis, PR BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI The structure of the solar wind at large heliocentric distances: CIRs and their successors SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID EVOLUTION; FLOWS; AU AB Go-rotating interaction regions (CIRs) and their associated shock pairs are dominant structures in the solar wind between the heliocentric distances of 2 and 8 AU. At larger heliocentric distances, these structures undergo a qualitative change. Shocks decay to a point where they are often difficult to detect, and may have little influence on the dynamics of the solar wind. Interaction regions spread and merge, though they appear to retain their identity to surprisingly large distances from the Sun. Solar wind and IMF data from the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were used to conduct a comprehensive survey of CIRs and their successors between heliocentric distances of 1 and 55 AU over the last two solar cycles. The structure of the solar wind varied in a consistent fashion with heliocentric distance. Similar structures were observed at similar heliocentric distances by all three spacecraft during different portions of the solar cycle. C1 NASA, Ames Res Ctr, SJSU Fdn, Moffett Field, CA 94035 USA. RP Gazis, PR (reprint author), NASA, Ames Res Ctr, SJSU Fdn, Moffett Field, CA 94035 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 767 EP 770 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700172 ER PT S AU Barnes, A AF Barnes, A BE Habbal, SR Esser, R Hollweg, JV Isenberg, PA TI Theory of the shape of the heliospheric termination shock: axial symmetry SO SOLAR WIND NINE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 9th International Solar Wind Conference CY OCT 05-09, 1998 CL NANTUCKET, MA SP Amer Inst Phys ID LOCAL INTERSTELLAR-MEDIUM; NONUNIFORM SOLAR-WIND; LATITUDE AB The heliospheric termination shock must exhibit asymmetry in its shape, due in part to internal latitude variations in the solar wind, and in part to the special directions defined by the external interstellar flow and/or the galactic magnetic field. This asymmetry shows up naturally in numerical simulations of the interaction between the heliosphere and local interstellar medium. However, to date only one analytical treatment of the theory has appeared (Barnes, 1998), which discussed the modification of the shock shape due to solar wind latitude variations in the presence of spherically symmetric outer boundary conditions. In the present report, we discuss an extension and generalization of this theory to an axially symmetric gasdynamic system, in which departure from spherical symmetry may be due either to internal solar wind variations or to the directional properties of the external interstellar medium. It is shown that for steady flow the post-shock region is characterized by an infinite set of quantities that are conserved along streamlines; among these invariants are the stagnation pressure and a quantity closely related to vorticity. Moreover, for a given latitude profile of the (supersonic) solar wind, the geometry of the termination shock uniquely determines the value of these invariants at the points where the streamlines emerge from the shock. In the case of flow into a static interstellar medium for which the appropriate boundary condition is that the stagnation pressure is the same for all streamlines, it can be shown that the location and shape of the termination shock, together with the entire heliosheath now, are completely determined by the external pressure plus the internal solar wind parameters. However, for even a slightly nonstatic interstellar flow, or for anisotropy in exterior conditions from any other cause, such as the galactic magnetic field, exterior interstellar plus interior solar-wind conditions do not uniquely determine the heliosheath flow field or the shape of the termination shock. A complete solution requires specification of additional conditions, such as the run of dynamic pressure across the distant wake, or the requirement that the heliosheath flow be vorticity-free. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Barnes, A (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-865-7 J9 AIP CONF PROC PY 1999 VL 471 BP 787 EP 789 PG 3 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BN29A UT WOS:000081435700177 ER PT S AU Watson, K Petersen, D Crockett, R AF Watson, K Petersen, D Crockett, R BE Bourell, DL Beaman, JJ Crawford, RH Marcus, HL Barlow, JW TI Application of solid freeform fabrication technology to NASA exploration missions SO SOLID FREEFORM FABRICATION PROCEEDINGS, AUGUST 1999 SE SOLID FREEFORM FABRICATION PROCEEDINGS (SERIES) LA English DT Proceedings Paper CT 10th Solid Freeform Fabrication Symposium (SFF) CY AUG 09-11, 1999 CL UNIV TEXAS, AUSTIN, TX SP USN, Off Res, Natl Sci Fdn, Univ Connecticut Storrs, Univ Texas Austin, Mech Engn Dept, Lab Freeform Fabricat, Univ Texas Austin, Mat Inst HO UNIV TEXAS ID BEHAVIOR; SYSTEMS; POWDER C1 NASA, Lyndon B Johnson Space Ctr, Explorat Off, Houston, TX 77058 USA. RP Watson, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Explorat Off, Houston, TX 77058 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU UNIV TEXAS AUSTIN PI AUSTIN PA MECHANICAL ENGINEERING DEPT, AUSTIN, TX 00000 USA SN 1053-2153 J9 SOL FREEFORM FABRIC PY 1999 BP 857 EP 864 PG 8 WC Computer Science, Interdisciplinary Applications; Engineering, Manufacturing; Materials Science, Multidisciplinary SC Computer Science; Engineering; Materials Science GA BQ40H UT WOS:000088256800100 ER PT J AU Liu, HL Zibold, A Tanner, DB Wang, YJ Burns, MJ Delin, KA Li, MY Wu, MK AF Liu, HL Zibold, A Tanner, DB Wang, YJ Burns, MJ Delin, KA Li, MY Wu, MK TI Far-infrared properties of superconducting YBa2Cu3O7-delta films in high magnetic fields SO SOLID STATE COMMUNICATIONS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPE; II SUPERCONDUCTORS; VORTEX DYNAMICS; MIXED-STATE; HIGH-T(C) SUPERCONDUCTORS; CUPRATE SUPERCONDUCTORS; CORE STRUCTURE; VORTICES; LINE; TC AB We report the far-infrared properties of superconducting ab plane-oriented YBa2Cu3O7-delta films in magnetic fields of up to 27 T. The applications of magnetic field (with H perpendicular to the ab plane and with unpolarized light) at low temperature produces no discernible field dependence. This observation differs from other previous far-infrared measurements in this temperature range. Only at fields and temperatures where the de resistance is not zero - on account of dissipative flux motion - is a field-induced effect observed. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Tsing Hua Univ, Dept Phys, Hsinchu 300, Taiwan. RP Liu, HL (reprint author), Univ Florida, Dept Phys, Gainesville, FL 32611 USA. RI Burns, Michael/D-2939-2011 OI Burns, Michael/0000-0001-9804-405X NR 42 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 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PY 1999 VL 109 IS 1 BP 7 EP 12 PG 6 WC Physics, Condensed Matter SC Physics GA 153ZE UT WOS:000077862900002 ER PT B AU Williams, RM Ryan, MA Homer, ML Lara, L Manatt, K Shields, V Cortez, RH Kulleck, J AF Williams, RM Ryan, MA Homer, ML Lara, L Manatt, K Shields, V Cortez, RH Kulleck, J BE Wachsman, ED Akridge, JR Liu, M Yamazoe, N TI The kinetics of thermal interconversion of sodium beta"-alumina with sodium beta alumina or alpha alumina at temperatures below 1600K in gaseous and liquid sodium SO SOLID-STATE IONIC DEVICES SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Solid-State Ionic Devices Symposium at the 195th Electrochemical-Society Meeting CY MAY 02-07, 1999 CL SEATTLE, WA SP Electrochem Soc ID INTERFACIAL IMPEDANCE; AMTEC ELECTRODES; TRANSFORMATION; BETA''-ALUMINA; TRANSPORT AB Sodium beta"-alumina is one of the best characterized solid electrolytes, but its chemistry at temperatures from 700K to 1600K is only partly understood. Simple thermal phase transitions between the beta and beta" crystal phases have been observed only at temperatures over about 1500K, and not at temperatures below 1300K. We have previously reported conversion of sodium beta"-alumina solid electrolyte (BASE) ceramic to alpha alumina at T > 1373K, decomposition of sodium beta"-alumina by reaction with Cr and Mn vapor at temperatures From 1173K to 1373K. We have also studied the stability of the beta"-alumina phase, in the absence of reactive metals, below 1273K for up to 500 hours in vacuum, low pressure sodium vapor, and liquid sodium. Here we report the stability of the beta"-alumina phase in low pressure sodium vapor at 1173 for 2500 hours, as determined by in situ ionic conductivity and charge transfer resistance measurements as well as experimental results which indicate decomposition of the NaAlO2 phase present at about 1% in the BASE ceramic, at a temperatures of 1173K or lower. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 6 Z9 6 U1 0 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-235-4 J9 ELEC SOC S PY 1999 VL 99 IS 13 BP 18 EP 26 PG 9 WC Electrochemistry; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Electrochemistry; Materials Science; Physics GA BN92R UT WOS:000083508300003 ER PT B AU Pines, V Chait, A Zlatkovsky, M AF Pines, V Chait, A Zlatkovsky, M BE Hofmeister, WH Rogers, JR Singh, NB Marsh, SP Vorhees, PW TI Dendrites, scaling laws, and dynamic evolution SO SOLIDIFICATION 1999 LA English DT Proceedings Paper CT Symposium on Solidification 1999 at the TMS Annual Meeting CY FEB 28-MAR 04, 1999 CL SAN DIEGO, CA SP TMS Mat Proc & Mfg Div Solidificat Comm ID GROWTH; MICROGRAVITY; NUCLEUS; SIZE AB Dendrites are among the most widely recognized and challenging to understand natural formations. In this work we explore less visited issues in the theories of dendritic growth. We present questions of fundamental nature concerning the role of evolution effects, anisotropy of surface tension, the adequacy of assuming a single scaling parameter and the connection among similar geometrical forms that undergo morphological instabilities. We attempt to answer some of these questions using a phenomenological theory, time-dependent stability analysis, and comparison among different geometries. We postulate the role of various physical parameters in the problem, and using a critical comparison with Glicksman's benchmark data, test some of these hypotheses. C1 NASA, Lewis Res Ctr, Computat Micrograv Lab, Cleveland, OH 44135 USA. RP Pines, V (reprint author), NASA, Lewis Res Ctr, Computat Micrograv Lab, Cleveland, OH 44135 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-429-1 PY 1999 BP 143 EP 149 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Crystallography; Materials Science; Metallurgy & Metallurgical Engineering GA BM93V UT WOS:000080192400014 ER PT B AU Robinson, MB Le, DL Rathz, TJ Williams, GA AF Robinson, MB Le, DL Rathz, TJ Williams, GA BE Hofmeister, WH Rogers, JR Singh, NB Marsh, SP Vorhees, PW TI Droplet growth in undercooled Cu-Co alloys SO SOLIDIFICATION 1999 LA English DT Proceedings Paper CT Symposium on Solidification 1999 at the TMS Annual Meeting CY FEB 28-MAR 04, 1999 CL SAN DIEGO, CA SP TMS Mat Proc & Mfg Div Solidificat Comm ID SOLIDIFICATION; MICROSTRUCTURE; KINETICS; SYSTEMS; COPPER; IRON AB High undercooling usually leads to the refinement of microstructures, while an opposite tendency occurs in liquid immiscible alloys. In the Cu-Co system, there is a metastable liquid miscibility gap which may allow the study of droplet nucleation and growth by undercooling experiments. In the present work, two alloys of Cu50Co50 and Cu68Co32 (atomic) were undercooled using a melt fluxing technique in which the liquid separation temperature could be directly measured. It was observed that after separation the resultant melts were further undercooled by 315 K prior to solidification. The relationship between the largest droplet radius and undercooling was found to exhibit three regimes: a power law growth, linear growth, and saturation stage. Tn addition to dendrites and droplet-like morphology reported previously, an interconnected structure was formed for the Cu50Co50 alloy at intermediate undercooling. It played a crucial role in droplet coarsening at high undercooling. C1 MSFC, NASA, Space Sci Lab, Huntsville, AL 35812 USA. RP Robinson, MB (reprint author), MSFC, NASA, Space Sci Lab, Huntsville, AL 35812 USA. NR 23 TC 1 Z9 1 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-429-1 PY 1999 BP 187 EP 196 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Crystallography; Materials Science; Metallurgy & Metallurgical Engineering GA BM93V UT WOS:000080192400018 ER PT J AU Pappa, RS AF Pappa, RS TI GIF animation of mode shapes and other data on the Internet SO SOUND AND VIBRATION LA English DT Article ID DATA-COMPRESSION AB The World Wide Web abounds with animated cartoons and advertisements competing for our attention. Most of these illustrations are animated Graphics Interchange Format (GIF) files. These files contain a series of ordinary GIF images plus control information and they provide an exceptionally simple, effective way to animate on the Internet, To date, however, this format has rarely been used for technical data, although there is no inherent reason not to do so. This article describes a procedure for creating high-resolution animated GIFs of mode shapes and other types of structural dynamics data with readily available software. The article shows three example applications using recent modal test data and video footage of a high-speed sled run. A fairly detailed summary of the GIF file format is provided in the appendix. All of the animations discussed in the paper are posted on the Internet at the following address: http://sdb-www.larc.nasa.gov/SDB/Research/data/pappa_data/imac17_figs. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Pappa, RS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 15 TC 0 Z9 0 U1 0 U2 1 PU ACOUSTICAL PUBL INC PI BAY VILLAGE PA 27101 E OVIATT RD PO BOX 40416, BAY VILLAGE, OH 44140 USA SN 0038-1810 J9 SOUND VIB JI Sound Vib. PD JAN PY 1999 VL 33 IS 1 BP 20 EP 28 PG 9 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 160FQ UT WOS:000078220100005 ER PT B AU Burke, JD AF Burke, JD BE Haskell, G Rycroft, M TI Tele-services between Earth and Moon: Information flow to and from lunar settlements SO SPACE AND THE GLOBAL VILLAGE: TELE-SERVICES FOR THE 21ST CENTURY SE SPACE STUDIES LA English DT Proceedings Paper CT International Symposium on Space and the Global Village - Tele-Services for the 21st Century CY JUN 03-05, 1998 CL STRASBOURG, FRANCE SP Int Space Univ AB In this paper let us examine the information flows between Earth's civilization and lunar settlements, founded in the 21st century and intended to grow productively thereafter. Information is the one valuable commodity instantly and cheaply transported between Earth and Moon, and so all kinds of tele-services are likely to flourish once lunar settlements exist. We shall consider them in the light of the symposium questions: new developments in tele-health and tele-education, new tele-services using space technology, organizational structures, legal and regulatory frameworks, new scientific foundations, benefits and dangers, and lessons to be learned. Some relevant activities need not wait for a decision to found lunar cities; they can start now because they have merit already, even before an extension of our global village to the Moon. ISU should play an important role in this development. We begin with a brief review of the natural limits controlling any kind of Earth-Moon communications, the main one being distance, ten times the range to geosynchronous orbit. Also, though Earth is nearly fixed in the sky as seen from the Moon, Earth's daily rotation dictates multiple ground stations, orbital relays, or both. For the wideband, multichannel information flows expected, optical links provide huge advantages and will undoubtedly be used. Maintaining a reliable service in the presence of the Earth's weather presents interesting technical and economic trade-offs whose solutions are likely to exist for other reasons long before they are needed for the lunar application. Next we examine likely types and rates of information flow, reasoning by analogy to what is already happening in intercity and international communications on Earth. Scientific, technical, business and entertainment communications, except those involving supercomputing, move at rates such that future radio and optical carriers will not constitute bottlenecks. However, the interconnections of those carriers, and particularly their costs and regulatory aspects, do limit services and so are drivers of technical, governmental, and economic change. The history of satellite relays and Internet growth is instructive, but it probably provides only a hint as to the complexity of the coming global village's nervous system. What does this mean with respect to lunar links? One obvious inference is that there will be a demand for enormously greater bandwidth, diversity and quality relative to the performance of the links used up to now for Apollo and other lunar missions, and used or planned for space stations. Going beyond technical matters, there is the question of privacy and control: already the Internet and many intranets are showing how controversial this can become. Once self-governing lunar settlements exist, similar problems are sure to arise. Finally, we propose one application of Earth-Moon-Earth communications that is important now, need not wait for humans to return to the Moon, and could contribute greatly to the quality and safety of a two-world global village. This is to begin building, on the Moon, a retrievable, polyglot robotic archive of accumulated human knowledge and wisdom. This paper gives reasons for such a project, addresses its risks and benefits, presents it as part of a natural evolution toward the information flows that lunar settlements will need, and suggests a role in it for the International Space University. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 16 TC 14 Z9 14 U1 2 U2 3 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5481-8 J9 SPAC STUD PY 1999 VL 3 BP 159 EP 172 PG 14 WC Engineering, Aerospace; Business; Medical Informatics; Telecommunications SC Engineering; Business & Economics; Medical Informatics; Telecommunications GA BN40E UT WOS:000081821100017 ER PT S AU Matney, M Goldstein, R Kessler, D Stansbery, E AF Matney, M Goldstein, R Kessler, D Stansbery, E BE Flury, W Klinkrad, H TI Recent results from Goldstone orbital debris radar SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res ID MILLIMETRIC SPACE DEBRIS AB On a limited basis, the National Aeronautics and Space Administration's (NASA's) Goldstone X-band radar has been available to-monitor the orbital debris environment. This powerful radar, which can detect a 3 mm diameter conducting sphere at a range of 1,000 km, fills a niche in MASA's ongoing program to monitor and mitigate the hazard of orbital debris. In this paper, we present flux measurements and other results of several years of monitoring. Some of the debris objects are observed to orbit in clusters, which indicates a common origin for them. One such cluster appears to be the remnants of 350 million copper dipoles, launched in 1961 as a communications experiment. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Lockheed Martin Space Mission Syst & Serv, Houston, TX 77058 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program off, Houston, TX 77058 USA. RP Matney, M (reprint author), Lockheed Martin Space Mission Syst & Serv, Mail Code C23,2400 NASA Rd 1, Houston, TX 77058 USA. NR 10 TC 6 Z9 7 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 5 EP 12 DI 10.1016/S0273-1177(98)00224-5 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700001 ER PT S AU Settecerri, TJ Stansbery, EG Matney, MJ AF Settecerri, TJ Stansbery, EG Matney, MJ BE Flury, W Klinkrad, H TI Haystack measurements of the orbital debris environment SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB The Haystack radar has been observing the orbital debris environment since October 1990. These measurements have provided orbital debris researchers with two important tools for characterizing the environment: 1) the ability to detect small size debris objects from previously unknown sources and 2) the ability to extend the size distribution from the catalog limit (approximate to 10 cm) down to 0.5 cm. Haystack data has identified small debris from several breakups and anomalous events: the Pegasus upper stage, satellite 23106; Cosmos 1484, satellite 14207; COBE, satellite 20332; Meteor 2-16 rocket body, satellite 18313; and the leakage of NaK droplets from the RORSAT class satellites. The time history of detection rate, and the flux, altitude, inclination, and size distributions have shown that the environment is very dynamic and the data is extremely useful as a benchmark for orbital debris modeling. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Lockheed Martin Space Mission Syst & Serv, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. RP Settecerri, TJ (reprint author), Lockheed Martin Space Mission Syst & Serv, 2400 NASA Rd 1, Houston, TX 77058 USA. NR 6 TC 4 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 13 EP 22 DI 10.1016/S0273-1177(98)00225-7 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700002 ER PT S AU Neish, MJ Kibe, S Yano, H Deshpande, SP Morishige, K AF Neish, MJ Kibe, S Yano, H Deshpande, SP Morishige, K BE Flury, W Klinkrad, H TI Post-flight analysis of the SFU: Current status and future plan SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB The Space Flyer Unit (SFU) has provided investigators in Japan with our first opportunity to conduct an extensive post-flight analysis (PFA) of particulate impacts on a retrieved satellite, and thereby further our goals in space debris research (Kibe et al., 1997). The PFA has now been in progress for some time, and in this paper the present status of our investigations is reported, our findings to date are briefly summarised, and finally a plan for the immediate future is outlined. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Natl Aerosp Lab, Space Environm Preservat Grp, Chofu, Tokyo 1828522, Japan. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Houston, TX 77058 USA. Deutsch Morgen Grenfell, Minato Ku, Tokyo 1050001, Japan. Inst Space & Astronaut Sci, Planetary Sci Div, Kanagawa 2298510, Japan. RP Neish, MJ (reprint author), Natl Aerosp Lab, Space Environm Preservat Grp, 7-44-1 Jindaijihigashi Machi, Chofu, Tokyo 1828522, Japan. NR 8 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 1999 VL 23 IS 1 BP 101 EP 111 DI 10.1016/S0273-1177(98)00236-1 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700013 ER PT S AU Morishige, K Yano, H Maekawa, Y Deshpande, SP Neish, MJ Kibe, S AF Morishige, K Yano, H Maekawa, Y Deshpande, SP Neish, MJ Kibe, S BE Flury, W Klinkrad, H TI Three dimensional analysis of impact crater profiles on the SFU spacecraft's Teflon radiators SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB We report on three dimensional morphology of about 100 hypervelocity impact craters on the Teflon radiators of the SFU spacecraft measured by scanning laser microscope and X-ray CT technique. We also performed impact calibration experiments using a two-stage light-gas gun at ISAS with alumina, glass and copper bead projectiles of diameters 50 to 80 mu m at velocities from 3.5 to 4.5 km/s, in order to reproduce impact crater profiles formed in space. As a result, the depth to diameter ratio of these impact craters constrains bulk density, velocity and size of impactors, which are complementary information to elemental analysis regarding the origin of the impactors, namely meteoroids or space debris. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Inst Space & Astronaut Sci, Planetary Sci Div, Kanagawa 2298510, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Nihon Univ, Narashino, Chiba 2758575, Japan. Deutsch Morgan Grenfell, Tokyo 1050001, Japan. Natl Aerosp Lab, Chofu, Tokyo 1828522, Japan. RP Morishige, K (reprint author), Inst Space & Astronaut Sci, Planetary Sci Div, Kanagawa 2298510, Japan. EM kazumasa@planeta.sci.isas.ac.jp NR 6 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 1999 VL 23 IS 1 BP 113 EP 117 DI 10.1016/S0273-1177(98)00237-3 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700014 ER PT S AU Hasegawa, S Fujiwara, A Yano, H Nisimura, T Sasaki, S Ohashi, H Iwai, T Kobayashi, K Shibata, H AF Hasegawa, S Fujiwara, A Yano, H Nisimura, T Sasaki, S Ohashi, H Iwai, T Kobayashi, K Shibata, H BE Flury, W Klinkrad, H TI Design of electrostatic accelerators for the development of microparticle detectors in Japan SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB Micrometeoroid detection in space usually involves high-velocity impact phenomena. In-situ dust detectors should be calibrated by a microparticle accelerator with a mass and velocity range comparable to micrometeoroids. A pilot model of an accelerator was constructed some years ago and fundamental research for an advanced facility has been performed. We are developing two new accelerators. A 3.75MV Van de Graaff electrostatic accelerator at The Research Center for Nuclear Science and Technology, University of Tokyo, has been modified to accelerate microparticles, and acceleration testing is now being carried but. The expected velocity range is 1-20 km/s for micron or sub-micron particles. Another small accelerator will be installed for easier handling, more frequent use, and lower-cost operation. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Inst Space & Astronaut Sci, Res Div Planetary Sci, Kanagawa 229, Japan. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Houston, TX 77058 USA. Inst Phys & Chem Res, Atom Phys Lab, Saitama, Japan. Univ Tokyo, Dept Geol, Tokyo, Japan. Tokyo Univ Fisheries, Dept Ocean Sci, Tokyo 108, Japan. Univ Tokyo, Nucl Sci & Technol Res Ctr, Tokyo 113, Japan. RP Hasegawa, S (reprint author), Inst Space & Astronaut Sci, Res Div Planetary Sci, Kanagawa 229, Japan. NR 5 TC 5 Z9 5 U1 1 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 119 EP 122 DI 10.1016/S0273-1177(98)00238-5 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700015 ER PT S AU Jenniskens, P AF Jenniskens, P BE Flury, W Klinkrad, H TI Update on the Leonids SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res ID METEOR STREAM ACTIVITY; COMET TEMPEL-TUTTLE; IMPACT PROBABILITIES; STORMS; SATELLITES; OUTBURST; DANGER AB Meteor storms are of concern to satellite operators because they are a natural impact hazard. Little is known about their cause and effect. Meteor storms are rare and have never been studied by modern techniques. Now, the upcoming Leonid returns of November '98 and '99 offer a once-in-a-lifetime opportunity to gather data that can help assess the impact hazard of meteor storms and provide a wealth of data on the physics and chemistry of meteoroids accreting into the Earth's atmosphere. Three months before the Nov. '98 return, we here give gn update of what to expect and what observing efforts are going to be made. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 34 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 137 EP 147 DI 10.1016/S0273-1177(98)00240-3 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700017 ER PT S AU Kessler, D Johnson, N Stansbery, E Reynolds, R Siebold, K Matney, M Jackson, A AF Kessler, D Johnson, N Stansbery, E Reynolds, R Siebold, K Matney, M Jackson, A BE Flury, W Klinkrad, H TI The importance of nonfragmentation sources of debris to the environment SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res ID ORBITAL DEBRIS AB Historically, satellite fragmentation has been assumed to be the major source of small orbital debris, based on U.S. Space Command observations. Although it was always known that only a few tens of kilograms of small debris could produce a significant debris hazard, there was no hard evidence that any space operations were releasing even these small quantities. Recent observations of small debris have led to the discovery of numerous nonfragmentation sources; in some cases, these sources have produced a hazard that exceeds the hazard from satellite breakups. In the centimeter-size range, these findings include aluminum oxide slag from solid rocket motors, sodium potassium droplets from coolant systems, and copper needles from U.S. experiments. Smaller debris include paint flecks from spacecraft surfaces and aluminum oxide dust from solid rocket motors. Since the number of known debris sources seems to be proportional to the amount of effort, expended looking for new sources and since observation programs to measure the small debris environment have just begun, many more sources are likely to be identified. These nonfragmentation sources could increase the need for mitigation efforts and complicate cost/benefit analyses of current efforts. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. Lockheed Martin Space Mission Syst & Serv, Houston, TX 77058 USA. RP Kessler, D (reprint author), 507 S Shadowbend, Friendswood, TX 77546 USA. NR 25 TC 9 Z9 9 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 149 EP 159 DI 10.1016/S0273-1177(98)00241-5 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700018 ER PT S AU Johnson, NL AF Johnson, NL BE Flury, W Klinkrad, H TI The cause and consequences of a satellite fragmentation: A case study SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB The fragmentation of a Pegasus Hydrazine Auxiliary Propulsion System upper stage on 3 June 1996 stands as the worst satellite breakup on record in terms of cataloged orbital debris. In addition to the more than 700 debris large enough to be tracked (approximately 10 cm in diameter or greater) in the 200 km by 2,000 km orbital regime by the U.S. Space Surveillance Network, a debris population of up to 300,000 objects larger than 4 mm appears to have been generated, based upon special radar observations. The debris cloud presented an immediate threat to many resident space objects, such as the Hubble Space Telescope, which resided in an orbit just 25 kin below the breakup altitude. Special analyses were required to ensure the safety of the STS-82 Hubble Space Telescope servicing mission in February 1997. This paper describes the activities undertaken-at the National Aeronautics and Space Administration Lyndon B. Johnson Space Center to characterize the near-term and far-term hazard of the debris cloud to manned and robotic spacecraft and to investigate the probable cause of the accident. The role of composite materials in the vehicle may have led to the creation of a much larger number of debris than would have been expected from a more conventional upper stage. To avoid a repetition of the incident, the Hydrazine Auxiliary Propulsion System upper stage was modified before its next launch, and additional passivation measures were adopted. This fragmentation event represents a textbook case for the hazards posed by satellite breakups and how fragmentation potential can be reduced without significantly affecting the capability of the vehicle. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 0 TC 8 Z9 8 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 165 EP 173 DI 10.1016/S0273-1177(98)00243-9 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700020 ER PT S AU Reynolds, R Eichler, P Bade, A Krisko, P Johnson, N AF Reynolds, R Eichler, P Bade, A Krisko, P Johnson, N BE Flury, W Klinkrad, H TI Sensitivity analysis of the orbital debris environment using the EVOLVE 4.0 model SO SPACE DEBRIS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT B0.2 Symposium of COSPAR Scientific Commission B on Space Debris at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Astronaut Federat, Int Astronom Union, UN Off Outer Space Affairs, Comm Space Res AB A number of models to describe the current and future orbital debris environments have been developed at the National Aeronautics and Space Administration Lyndon B. Johnson Space Center. One of these models, EVOLVE, is a complex simulation model that uses future space traffic, fragmentations, and nonfragmentation processes to predict future environments for debris 1 mm in diameter and larger. New breakup models incorporating new data on orbiting fragmentation debris, as well as new data from laboratory tests, are being developed for use by EVOLVE. These models will have different size, area-to-mass, and velocity distributions than in the current baselines. With the inclusion of the new breakup models, EVOLVE will be upgraded to version 4.0. Because there is limited data on debris sources and uncertainty in the importance of these sources in future debris environment evolution, it is important to understand the sensitivity of environment projections to these uncertainties. To calculate the sensitivity of the environment to characteristics of the debris sources, alternative environment projections will be obtained by making a series of modifications to the nominal source characteristics in EVOLVE. These modifications (e.g., to the traffic model and postmission disposal model) and the planned sensitivity study framework are described in this paper. Metrics for determining change in the environment are also defined in the paper and used to discuss sensitivities. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Lockheed Martin Space Mission Syst & Serv, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. RP Reynolds, R (reprint author), Lockheed Martin Space Mission Syst & Serv, 2400 NASA Rd 1, Houston, TX 77058 USA. NR 8 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 1 BP 175 EP 185 DI 10.1016/S0273-1177(99)00002-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BM98C UT WOS:000080334700021 ER PT S AU Lee, AT Loftus, JP AF Lee, AT Loftus, JP BE Heath, GW TI Metrics for software risk assessment: A cost saving approach SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB For the purpose of adapting to the budgetary constraint but not sacrificing product quality, this paper originates an end-to-end approach which consists of a series of quantitative measurement methodologies to assess the risk of safety-critical software. The methodologies are performed during the various phases of the software development life cycle as follows: 1. Assessing functional criticality during the requirement and preliminary design phases. 2. Performing error prediction based on code structure and complexity metrics during the coding phase in four aspects: maintainability, complexity, interface criticality, and testability. 3. Analyzing test case coverage during the sub-system testing phase to detect untested code and area. 4. Performing software reliability estimation and prediction during the system integration and testing phase. The failure intensity and failure rate objective together will predict the time required to complete testing as well as the maturity of the software. 5. Compiling the results of the above sequential analyses and deriving a risk index and a Reliability number. The risk index indicates the problem areas and readiness of the software in an integrated view. C1 NASA, Lyndon B Johnson Space Ctr, Safety Reliabil & Qual Assurance Off, Houston, TX 77058 USA. RP Lee, AT (reprint author), NASA, Lyndon B Johnson Space Ctr, Safety Reliabil & Qual Assurance Off, Houston, TX 77058 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 53 EP 61 PG 9 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200005 ER PT S AU Greenfield, MA AF Greenfield, MA BE Heath, GW TI Risk as a resource SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB Today's NASA must align its spacecraft missions with the dramatic decline in its budget. In the past, NASA's spacecraft development processes were characterized by extensive analyses, numerous reviews, and multiple conservative tests. This methodology was consistent with the long available schedules for developing the hardware and software for very large, billion dollar spacecraft. Although this approach served the Agency well, those days are now over. High budget spacecraft projects with extensive testing are being replaced by "faster, better, cheaper" projects which require that risk be managed differently-the "risk as a resource" approach. In this approach, risk drivers are identified and planned for early in the project life cycle. Once a risk is understood it can be traded as a resource in much the same way as other resources. Although some failures may occur, this methodology allows many more spacecraft to be built in less time and for much less money. This paper will detail the concept of "risk as a resource" and trades that can be made which result in an optimum risk posture. C1 NASA, Washington, DC 20546 USA. RP Greenfield, MA (reprint author), NASA, Code Q, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 99 EP 107 PG 9 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200009 ER PT S AU Johnson, NL AF Johnson, NL BE Heath, GW TI The world state of orbital debris measurements and modeling SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB For more than 20 years orbital debris research around the world has been striving to obtain a sharper, more comprehensive picture of the near-Earth artificial satellite environment. Whereas significant progress has been achieved through better organized and funded programs and with the assistance of advancing technologies in both space surveillance sensors and computational capabilities, the potential of measurements and modeling of orbital debris has yet to be realized. Greater emphasis on a systems-level approach to the characterization and projection of the orbital debris environment would prove beneficial. On-going space surveillance activities, primarily from terrestrial-based facilities, are narrowing the uncertainties of the orbital debris population for objects greater than 2 mm in LEO and offer a better understanding of the GEO regime down to 10 cm diameter objects. In situ data collected in LEO is limited to a narrow range of altitudes and should be employed with great care. Orbital debris modeling efforts should place high priority on improving model fidelity, on clearly and completely delineating assumptions and simplifications, and on more thorough sensitivity studies. Most importantly, however, greater communications and cooperation between the measurements and modeling communities are essential for the efficient advancement of the field. The advent of the Inter-Agency Space Debris Coordination Committee (IADC) in 1993 has facilitated this exchange of data and modeling techniques. A joint goal of these communities should be the identification of new sources of orbital debris. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, SN3, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 121 EP 128 PG 8 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200011 ER PT S AU Johnson, NL AF Johnson, NL BE Heath, GW TI The reentry of large orbital debris SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB The natural reentry of a large space object occasionally commands international attention, as in the orbital decays of the Skylab and Salyut 7 space stations, the nuclear-powered Kosmos 954 and Kosmos 1402 spacecraft, and the FSW 1-5 recoverable capsule. However, on average a piece of large orbital debris (radar cross-section > 1 m(2)) falls back to Earth once or twice a week. These objects ate normally inactive spacecraft, expended launch vehicle upper stages, and hardware associated with launch vehicle and spacecraft deployments or operations. The time and geographic location of entry into the dense atmosphere is projected or recorded by U.S. national technical means. An examination of 331 such reentries which occurred during the September 1992 - December 1996 period was conducted, in part, to determine if impact tones were randomly distributed about the Earth as has been assumed, despite the planet's asymmetrical atmosphere and gravitational field. For objects in orbit for more than 30 days, reentry locations were found to be essentially uniform in terms of latitude and longitude. However, for recently launched objects (orbital lifetime less than 30 days), the reentries demonstrated a greater probability for Northern Hemisphere impacts. No significant differences were discovered among the three categories of objects: spacecraft, upper stages, and debris. The individual and aggregate masses of the subject reentries were also evaluated, and the issues of debris survivability and ground dispersal were addressed. Unfortunately, the capability to predict accurately the time and location of natural reentries does not yet exist. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, SN3, Houston, TX 77058 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 285 EP 293 PG 9 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200023 ER PT S AU Loftus, JP Pearson, DJ Christensen, EL AF Loftus, JP Pearson, DJ Christensen, EL BE Heath, GW TI Orbital debris risk assessments and collision avoidance procedures for the Space Shuttle SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB This paper describes the background and flight history of flight control operations used by NASA in the Space Shuttle program to assess conjunctions with orbiting objects and to avoid collision with these objects. Additionally, new NASA real-time processes for managing conjunctions associated with the Mir Space Station and the International Space Station (TSS) are described. The Space Shuttle has logged more than 500 days of on-orbit operations. During this time, there have been many instances of orbiting satellites and debris coming close to the Space Shuttle. In some instances these close conjunctions have required the Space Shuttle to perform evasive maneuvers in order to mitigate the risk of collision. For Space Shuttle operations, the flight control team and USSPACECOM utilize a standard procedure for evaluating possible conjunctions and deciding when to perform evasive maneuvers. This standard procedure and associated mission rules are presented along with a technical background used to baseline this technique. Actual conjunction flight history data is presented. With the recent addition of American astronauts to Mir, NASA and USSPACECOM have baselined a new procedure to monitor conjunctions which utilizes a method not requiring flight controllers to be continuously on console in order to provide this support. Finally, a new probability-based real-time procedure is being introduced with the International Space Station program in order to improve the collision avoidance process and reduce the number of evasive maneuvers required to mitigate risk. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Loftus, JP (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 335 EP 341 PG 7 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200027 ER PT S AU Mendell, WW Kessler, DJ Reynolds, RC AF Mendell, WW Kessler, DJ Reynolds, RC BE Heath, GW TI Telecommunications satellite constellations and the LEO debris population SO SPACE SAFETY AND RESCUE 1997 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 30th International Symposium on Safety, Rescue, and Quality of the IAA in conjunction with the 48th International-Astronautical-Federation-Congress CY OCT 06-10, 1997 CL TURIN, ITALY SP Int Acad Astronaut, Int Astronaut Federat AB An explosion of investment in telecommunications has resulted in plans for many new satellite constellations in low Earth orbit (LEO). in turn, the rapid growth in commercial launches has brought about new investment in privately developed, low-cost launch vehicles, whose attractive launch prices are intended to stimulate even more satellite development. The presence of large numbers of commercial satellites is a new phenomenon for modelers of space debris. The constellation satellites have the property that they are managed in a manner so as not to collide with each other; and, therefore, they represent a class of objects that violates the assumption of random collisions in debris models. We present here a simple model, based on the "Particle in a Box" methodology, which tracks separately a "debris" population fi om a "satellite" population. Our first results indicate that "satellite-satellite" collisions play a minor role in the generation of the LEO debris population. Consequently, lack of mutual collisions among constellations increases the survivability of the "satellite" population very slightly but has a negligible effect on long term evolution of the environment. The growth of the "debris" population is the dominant factor in collisional interactions. However, the model suggests that a policy to deorbit nonfunctional bodies and launch only replacement objects can halt growth of the debris population if implemented within the next two decades. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Mendell, WW (reprint author), NASA, Lyndon B Johnson Space Ctr, SN2,2101 NASA Rd 1, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-454-0 J9 SCI TECH PY 1999 VL 96 BP 351 EP 364 PG 14 WC Engineering, Aerospace SC Engineering GA BM64H UT WOS:000079326200029 ER PT J AU Hanner, MS AF Hanner, MS TI The silicate material in comets SO SPACE SCIENCE REVIEWS LA English DT Review DE comets; Hale-Bopp; silicates; infrared spectra ID INTERPLANETARY DUST PARTICLES; HALE-BOPP C/1995-O1; HALLEY DUST; SPECTRA; GRAINS; P/HALLEY; SPECTROPHOTOMETRY; SPECTROSCOPY; SIMULATION; MINERALOGY AB Silicates in comets appear to be a mix of high-temperature crystalline enstatite and forsterite plus glassy or amorphous grains that formed at lower temperatures. The mineral identifications from the 10 and 20 mu m cometary spectra are consistent with the composition of anhydrous chondritic aggregate IDPs. The origin of the cometary silicates remains puzzling. While the evidence from the IDPs points to a pre-solar origin of both crystalline and glassy components, the signatures of crystalline silicates appear in the spectra of young stellar objects only at a late evolutionary stage, when comets are the likely source of the dust. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 183-501, Pasadena, CA 91109 USA. EM msh@scnl.jpl.nasa.gov NR 45 TC 59 Z9 60 U1 0 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 90 IS 1-2 BP 99 EP 108 DI 10.1023/A:1005285711945 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279QN UT WOS:000085056800011 ER PT J AU Enzian, A AF Enzian, A TI On the prediction of CO outgassing from Comets Hale-Bopp and Wirtanen SO SPACE SCIENCE REVIEWS LA English DT Review DE thermal modeling; comet nucleus; Hale-Bopp; Wirtanen ID WATER ICE; NUCLEUS; MODEL AB The gas flux from a volatile icy-dust mixture is computed using a comet nucleus thermal model in order to study the evolution of CO outgassing during several apparitions from long-period Comet Hale-Bopp and short-period Comet Wirtanen. The comet model assumes a spherical, porous body containing a dust component, one major ice component (H2O), and one minor ice component of higher volatility (CO). The initial chemical composition is assumed to be homogeneous. The following processes are taken into account: heat and gas diffusion inside the rotating nucleus; release of outward diffusing gas from the corner nucleus: chemical differentiation by sublimation of volatile ices in the surface layers and recondensation of gas in deeper, cooler layers. A 2-D time dependent solution is obtained through the dependence of the boundary conditions on the local solar illumination as the nucleus rotates. The model for Comet Hale-Bopp was compared with observational measurements (Biver et nl,, 1999). The best agreement was obtained for a model with amorphous water ice and CO, assuming that a part of the latter is trapped by the water ice, another part is condensed as an independent ice phase. The model confirms that sublimation of CO ice at large heliocentric distance produces a gradual increase in the comet's activity as it approaches the Sun. Crystallization of amorphous water ice begins at 7 AU from the Sun, but no outbursts were found. Seasonal effects and thermal inertia of the nucleus material lead to larger CO outgassing rates as the comet recedes from the Sun. In the second part of this work the model was run with the orbital parameters of Comet Wirtanen. Unlike Comet Hale-Bopp, the predicted CO outgassing from Comet Wirtanen is almost constant throughout its orbit. Such behavior can be explained by a thermally evolved and chemically differentiated comet nucleus. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, MS 183-601, Pasadena, CA 91109 USA. EM achim.enzian@jpl.nasa.gov NR 19 TC 12 Z9 13 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 90 IS 1-2 BP 131 EP 139 DI 10.1023/A:1005293913762 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279QN UT WOS:000085056800014 ER PT J AU Allamandola, LJ Bernstein, MP Sandford, SA Walker, RL AF Allamandola, LJ Bernstein, MP Sandford, SA Walker, RL TI Evolution of interstellar ices SO SPACE SCIENCE REVIEWS LA English DT Review ID INTERPLANETARY DUST PARTICLES; TAURUS DARK CLOUD; SOLID CO; INFRARED-SPECTROSCOPY; ABSORPTION FEATURES; MOLECULAR CLOUDS; GRAIN MANTLES; AROMATIC-MOLECULES; MICRON ABSORPTION; XCN BAND AB Infrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Ices in molecular clouds are dominated by the very simple molecules H2O, CH3OH, NH3, CO, CO2, and probably H2CO and H-2. More complex species including nitriles, ketones, and esters are also present, but at lower concentrations. The evidence for these, as well as the abundant, carbon-rich, interstellar, polycyclic aromatic hydrocarbons (PAHs) is reviewed. Other possible contributors to the interstellar/pre-cometary ice composition include accretion of gas-phase molecules and in situ photochemical processing. By virtue of their low abundance, accretion of simple gas-phase species is shown to be the least important of the processes considered in determining ice composition. On the other hand, photochemical processing does play an important role in driving dust evolution and the composition of minor species. Ultraviolet photolysis of realistic laboratory analogs readily produces H-2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including amides, ketones, and polyoxymethylenes (POMs). Inclusion of PAHs in the ices produces many species similar to those found in meteorites including aromatic alcohols, quinones and ethers. Photon assisted PAH-ice deuterium exchange also occurs. All of these species are readily formed and are therefore likely cometary constituents. C1 NASA, Ames Res Ctr, Astrochem Lab, Mountain View, CA 94035 USA. RP NASA, Ames Res Ctr, Astrochem Lab, MS 245-6, Mountain View, CA 94035 USA. EM lallamandola@mail.arc.nasa.gov NR 73 TC 114 Z9 114 U1 1 U2 28 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 90 IS 1-2 BP 219 EP 232 DI 10.1023/A:1005210417396 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279QN UT WOS:000085056800021 PM 11543288 ER PT J AU Weissman, PR AF Weissman, PR TI Diversity of comets: Formation zones and dynamical paths SO SPACE SCIENCE REVIEWS LA English DT Review DE Oort cloud; Kuiper belt; formation zones; dynamical evolution; physical processing ID SHORT-PERIOD COMETS; EDGEWORTH-KUIPER BELT; JUPITER-FAMILY COMETS; OORT CLOUD; ORIGIN; EVOLUTION; OBJECTS; NEPTUNE AB The past dozen years have produced a new paradigm with regard to the source regions of comets in the early solar system. It is now widely recognized that the likely source of the Jupiter-family short-period comets (those with Tisserand parameters, T > 2 and periods: P, generally < 20 years) is the Kuiper belt in the ecliptic plane beyond Neptune. In contrast, the source of the Halley-type and long-period comets (those with T < 2 and P > 20 years) appears to be the Oort cloud. However, the corners in the Oort cloud almost certainly originated elsewhere, since accretion is very inefficient at such large heliocentric distances. New dynamical studies now suggest that the source of the Oort cloud comets is the entire giant planets region from Jupiter to Neptune, rather than primarily the Uranus-Neptune region, as previously thought. Some fraction of the Oort cloud population may even be asteroidal bodies formed inside the orbit of Jupiter. These comets and asteroids underwent a complex dynamical random walk among the giant planets before they were ejected to distant orbits in the Oort cloud, with possible interesting consequences for their thermal and collisional histories. Observational evidence for diversity in cometary compositions is limited, at best. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Div Earth & Space Sci, Mail Stop 183-601,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM pweissman@issac.jpl.nasa.gov NR 32 TC 18 Z9 18 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 90 IS 1-2 BP 301 EP 311 DI 10.1023/A:1005278905101 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279QN UT WOS:000085056800028 ER PT J AU Reames, DV AF Reames, DV TI Particle acceleration at the Sun and in the heliosphere SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR ENERGETIC PARTICLES; ANOMALOUS COSMIC-RAYS; CORONAL MASS EJECTIONS; EARTHS BOW SHOCK; COROTATING INTERACTION REGIONS; QUASI-LINEAR THEORY; INTERPLANETARY TRAVELING SHOCKS; HYDROMAGNETIC WAVE EXCITATION; LARGE HELIOCENTRIC DISTANCES; STORM SUDDEN COMMENCEMENTS AB Energetic particles are accelerated in rich profusion at sites throughout the heliosphere. They come from solar flares in the low corona, from shock waves driven outward by coronal mass ejections (CMEs), from planetary magnetospheres and bow shocks. They come from corotating interaction regions (CIRs) produced by high-speed streams in the solar wind, and from the heliospheric termination shock at the outer edge of the heliospheric cavity. We sample many populations near Earth, but can distinguish them readily by their element and isotope abundances, ionization states, energy spectra, angular distributions and time behavior. Remote spacecraft have probed the spatial distributions of the particles and examined new sources in situ. Most acceleration sources can be 'seen' only by direct observation of the particles; few photons are produced at these sites. Wave-particle interactions are an essential feature in acceleration sources and, for shock acceleration, new evidence of energetic-proton-generated waves has come from abundance variations and from local cross-field scattering. Element abundances often tell us the physics of the source plasma itself, prior to acceleration. By comparing different populations, we learn more about the sources, and about the physics of acceleration and transport, than we can possibly learn from one source alone. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reames, DV (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Reames@lheavx.gsfc.nasa.gov NR 295 TC 863 Z9 881 U1 7 U2 35 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 90 IS 3-4 BP 413 EP 491 DI 10.1023/A:1005105831781 PG 79 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 278NL UT WOS:000084995800001 ER PT J AU Balogh, A Bothmer, V Crooker, NU Forsyth, RJ Gloeckler, G Hewish, A Hilchenbach, M Kallenbach, R Klecker, B Linker, JA Lucek, E Mann, G Marsch, E Posner, A Richardson, IG Schmidt, JM Scholer, M Wang, YM Wimmer-Schweingruber, RF Aellig, MR Bochsler, P Hefti, S Mikic, Z AF Balogh, A Bothmer, V Crooker, NU Forsyth, RJ Gloeckler, G Hewish, A Hilchenbach, M Kallenbach, R Klecker, B Linker, JA Lucek, E Mann, G Marsch, E Posner, A Richardson, IG Schmidt, JM Scholer, M Wang, YM Wimmer-Schweingruber, RF Aellig, MR Bochsler, P Hefti, S Mikic, Z CA Working Grp 1 TI The solar origin of corotating interaction regions and their formation in the inner heliosphere - Report of Working Group 1 SO SPACE SCIENCE REVIEWS LA English DT Review ID ULTRAVIOLET CORONAGRAPH SPECTROMETER; WIND STREAM INTERFACES; HIGH-SPEED STREAM; CURRENT SHEET; MINIMUM ACTIVITY; SOHO; ULYSSES; EVOLUTION; SOHO/CELIAS/CTOF; PARAMETERS AB Corotating Interaction Regions (CIRs) form as a consequence of the compression of the solar wind at the interface between fast speed streams and slow streams. Dynamic interaction of solar wind streams is a general feature of the heliospheric medium; when the sources of the solar wind streams are relatively stable, the interaction regions form a pattern which corotates with the Sun. The regions of origin of the high speed solar wind streams have been clearly identified as the coronal holes with their open magnetic field structures. The origin of the slow speed solar wind is less clear; slow streams may well originate from a range of coronal configurations adjacent to, or above magnetically closed structures. This article addresses the coronal origin of the stable pattern of solar wind streams which leads to the formation of CIRs. In particular, coronal models based on photospheric measurements are reviewed; we also examine the observations of kinematic and compositional solar wind features at 1 AU, their appearance in the stream interfaces (SIs) of CIRs, and their relationship to the structure of the solar surface and the inner corona; finally we summarise the Helios observations in the inner heliosphere of CIRs and their precursors to give a link between the optical observations on their solar origin and the in-situ plasma observations at 1 AU after their formation. The most important question that remains to be answered concerning the solar origin of CIRs is related to the origin and morphology of the slow solar wind. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Univ Kiel, Kiel, Germany. Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Cambridge, Cavendish Lab, Mullard Radio Astron Observ, Cambridge CB3 0HE, England. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Int Space Sci Inst, Bern, Switzerland. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Sci Applicat Int Corp, San Diego, CA 92121 USA. Inst Astrophys, Potsdam, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. Univ Bern, Inst Phys, Bern, Switzerland. RP Balogh, A (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Prince Consort Rd, London SW7 2BZ, England. EM a.balogh@ic.ac.uk; vbothmer@kernphysik.uni-kiel.de; crooker@buasta.bu.edu; r.forsyth@ic.ac.uk; gg10@pop.umail.umd.edu; ah120@mrao.cam.ac.uk; hilchenbach@roland4.mpae.gwdg.de; kallenbach@issi.unibe.ch; bek@mpesmp.mpe-garching.mpg.de; linker@iris023.saic.com; e.lucek@ic.ac.uk; gmann@aip.de; marsch@linax1.dnet.gwdg.de; aposner@kernphysik.uni-kiel.de; richardson@lheavx.gsfc.nasa.gov; j.m.schmidt@ic.ac.uk; mbs@mpe-garching.mpg.de; ywang@yucca.nrl.navy.mil; wimmer@phim.unibe.ch OI Schmidt, Joachim/0000-0002-7927-0665; Richardson, Ian/0000-0002-3855-3634 NR 68 TC 45 Z9 46 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 141 EP 178 DI 10.1023/A:1005245306874 PG 38 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200011 ER PT J AU Crooker, NU Gosling, JT Bothmer, V Forsyth, RJ Gazis, PR Hewish, A Horbury, TS Intriligator, DS Jokipii, JR Kota, J Lazarus, AJ Lee, MA Lucek, E Marsch, E Posner, A Richardson, IG Roelof, EC Schmidt, JM Siscoe, GL Tsurutani, BT Wimmer-Schweingruber, RF AF Crooker, NU Gosling, JT Bothmer, V Forsyth, RJ Gazis, PR Hewish, A Horbury, TS Intriligator, DS Jokipii, JR Kota, J Lazarus, AJ Lee, MA Lucek, E Marsch, E Posner, A Richardson, IG Roelof, EC Schmidt, JM Siscoe, GL Tsurutani, BT Wimmer-Schweingruber, RF CA Working Grp 2 TI CIR morphology, turbulence, discontinuities, and energetic particles - Report of Working Group 2 SO SPACE SCIENCE REVIEWS LA English DT Review ID COROTATING INTERACTION REGIONS; HELIOSPHERIC CURRENT SHEET; SOLAR-WIND STREAM; ULYSSES OBSERVATIONS; CORONAL STREAMERS; COSMIC-RAYS; 1 AU; INTERPLANETARY ACCELERATION; SECTOR BOUNDARIES; ECLIPTIC-PLANE AB Corotating interaction regions (CIRs) in the middle heliosphere have distinct morphological features and associated patterns of turbulence and energetic particles. This report summarizes current understanding of those features and patterns, discusses how they can vary from case to case and with distance from the Sun and possible causes of those variations, presents an analytical model of the morphological features found in earlier qualitative models and numerical simulations, and identifies aspects of the features and patterns that have yet to be resolved. C1 Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Kiel, Kiel, Germany. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. NASA, San Jose State Univ Fdn, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Cambridge, Cavendish Lab, Mullard Radio Astron Observ, Cambridge CB3 0HE, England. Carmel Res Ctr, Santa Monica, CA USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Arizona, Dept Astron, Tucson, AZ USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Bern, Inst Phys, Bern, Switzerland. RP Crooker, NU (reprint author), Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. EM crooker@buasta.bu.edu; jgosling@lan1.gov; vbothmer@kernphysik.uni-kiel.de; r.forsyth@ic.ac.uk; gazis@arwen.arc.nasa.gov; ah120@mrao.cam.ac.uk; t.horbury@qmw.ac.uk; DevrieI@aol.com; jokipii@lpl.arizona.edu; kota@lpl.arizona.edu; ajl@space.mit.edu; marty.lee@unh.edu; e.lucek@ic.ac.uk; marsch@linax1.dnet.gwdg.de; aposner@kernphysik.uni-kiel.de; richardson@lheavx.gsfc.nasa.gov; edmond.roelof@jhuapl.edu; j.m.schmidt@ic.ac.uk; btsurutani@jplsp2.jpl.nasa.gov; wimmer@phim.unibe.ch OI Schmidt, Joachim/0000-0002-7927-0665; Richardson, Ian/0000-0002-3855-3634 NR 72 TC 55 Z9 55 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 179 EP 220 DI 10.1023/A:1005253526438 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200012 ER PT J AU Kunow, H Lee, MA Fisk, LA Forsyth, RJ Heber, B Horbury, TS Keppler, E Kota, J Lou, YQ McKibben, RB Paizis, C Potgieter, MS Roelof, EC Sanderson, TR Simnett, GM Von Steiger, R Tsurutani, BT Wimmer-Schweingruber, RF Jokipii, JR AF Kunow, H Lee, MA Fisk, LA Forsyth, RJ Heber, B Horbury, TS Keppler, E Kota, J Lou, YQ McKibben, RB Paizis, C Potgieter, MS Roelof, EC Sanderson, TR Simnett, GM Von Steiger, R Tsurutani, BT Wimmer-Schweingruber, RF Jokipii, JR CA Working Grp 3 TI Corotating interaction regions at high latitudes - Report of Working Group 3 SO SPACE SCIENCE REVIEWS LA English DT Review DE Solar wind; interplanetary medium; CIRs; high latitude heliosphere ID HELIOSPHERIC MAGNETIC-FIELD; SOLAR-WIND STREAM; INTERPLANETARY SECTOR STRUCTURE; ROTATING INTERACTION REGIONS; HIGH HELIOGRAPHIC LATITUDES; PLANETARY CURRENT SHEET; GALACTIC COSMIC-RAYS; ULYSSES OBSERVATIONS; ECLIPTIC-PLANE; ENERGETIC PARTICLES AB Ulysses observed a stable strong CIR from early 1992 through 1994 during its first journey into the southern hemisphere. After the rapid latitude scan in early 1995, Ulysses observed a weaker CIR from early 1996 to mid-1997 in the northern hemisphere as it traveled back to the ecliptic at the orbit of Jupiter. These two CIRs are the observational basis of the investigation into the latitudinal structure of CIRs. The first CIR was caused by an extension of the northern coronal hole into the southern hemisphere during declining solar activity, whereas the second CIR near solar minimum activity was caused by small warps in the streamer belt. The latitudinal structure is described through the presentation of three 26-day periods during the southern CIR. The first at similar to 24 degrees S shows the full plasma interaction region including fast and slow wind streams, the compressed shocked flows with embedded stream interface and heliospheric current sheet (HCS), and the forward and reverse shocks with associated accelerated ions and electrons. The second at 40 degrees S exhibits only the reverse shock, accelerated particles, and the 26-day modulation of cosmic rays. The third at 60 degrees S shows only the accelerated particles and modulated cosmic rays. The possible mechanisms for the access of the accelerated particles and the CIR-modulated cosmic rays to high latitudes above the plasma interaction region are presented. They include direct magnetic field connection across latitude due to stochastic field line weaving or to systematic weaving caused by solar differential rotation combined with non-radial expansion of the fast wind. Another possible mechanism is particle diffusion across the average magnetic field, which includes stochastic field line weaving. A constraint on connection to a distant portion of the CIR is energy loss in the solar wind, which is substantial for the relatively slow-moving accelerated ions. Finally, the weaker northern CIR is compared with the southern CIR. It is weak because the inclination of the streamer belt and HCS decreased as Ulysses traveled to lower latitudes so that the spacecraft remained at about the maximum latitudinal extent of the HCS. C1 Univ Kiel, Inst Expt & Angew Phys, D-24118 Kiel, Germany. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Univ Michigan, Dept Atmospher & Space Sci, Ann Arbor, MI 48109 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Arizona, Dept Astron, Tucson, AZ USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Milan, Dipartimento Fis, Milan, Italy. Potchefstroom Univ Christian Higher Educ, ZA-2520 Potchefstroom, South Africa. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. ESA, ESTEC, Dept Space Sci, Noordwijk, Netherlands. Univ Birmingham, Dept Phys & Astron, Birmingham, W Midlands, England. Int Space Sci Inst, Bern, Switzerland. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Bern, Inst Phys, Bern, Switzerland. RP Kunow, H (reprint author), Univ Kiel, Inst Expt & Angew Phys, Leibnizstr 11-19, D-24118 Kiel, Germany. RI Von Steiger, Rudolf/F-6822-2011 OI Von Steiger, Rudolf/0000-0002-3350-0023 NR 71 TC 11 Z9 11 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 221 EP 268 DI 10.1023/A:1005218010508 PG 48 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200013 ER PT J AU Gazis, PR McDonald, FB Burger, RA Chalov, S Decker, RB Dwyer, J Intriligator, DS Jokipii, JR Lazarus, AJ Mason, GM Pizzo, VJ Potgieter, MS Richardson, IG Lanzerotti, LJ AF Gazis, PR McDonald, FB Burger, RA Chalov, S Decker, RB Dwyer, J Intriligator, DS Jokipii, JR Lazarus, AJ Mason, GM Pizzo, VJ Potgieter, MS Richardson, IG Lanzerotti, LJ CA Working Grp 4 TI Corotating interaction regions in the outer heliosphere - Report of Working Group 4 SO SPACE SCIENCE REVIEWS LA English DT Review ID GALACTIC COSMIC-RAYS; MERGED INTERACTION REGIONS; DEPENDENT DRIFT MODEL; LONG-TERM MODULATION; LARGE HELIOCENTRIC DISTANCES; QUASI-STEADY DYNAMICS; SOLAR-WIND; VOYAGER-2 OBSERVATIONS; SIMULATED FEATURES; PIONEER OBSERVATIONS AB We discuss the structure and evolution of CIRs and their successors in the outer heliosphere. These structures undergo significant evolution as they are convected to greater heliocentric distances. A progression of different types of structure are observed at increasing distance from the Sun. Similar structures are observed at similar heliocentric distance at different portions of the solar cycle. CIRs and their successors are associated with many important physical processes in the outer heliosphere. We discuss the relationship between these structures and recurrent phenomena such as cosmic ray variations, and review some of the associated theoretical models on the role of corotating structures and global merged interaction regions (GMIRs) in global cosmic ray modulation. We also discuss some outstanding questions related to the origin of non-dispersive quasi-periodic particle enhancements associated with CIRs and their successors in the outer heliosphere. C1 NASA, SJSU Fdn, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Potchefstroom Univ Christian Higher Educ, ZA-2520 Potchefstroom, South Africa. Russian Acad Sci, Inst Problems Mech, Moscow 117526, Russia. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Carmel Res Ctr, Santa Monica, CA USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Arizona, Dept Astron, Tucson, AZ USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. NOAA, SEC, Boulder, CO USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. AT&T Bell Labs, Murray Hill, NJ USA. RP Gazis, PR (reprint author), NASA, SJSU Fdn, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. OI Richardson, Ian/0000-0002-3855-3634 NR 77 TC 10 Z9 10 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 269 EP 305 DI 10.1023/A:1005270027347 PG 37 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200014 ER PT J AU McKibben, RB Jokipii, JR Burger, RA Heber, B Kota, J McDonald, FB Paizis, C Potgieter, MS Richardson, IG AF McKibben, RB Jokipii, JR Burger, RA Heber, B Kota, J McDonald, FB Paizis, C Potgieter, MS Richardson, IG TI Modulation of cosmic rays and anomalous components by CIRs - Report of Working Group 5 SO SPACE SCIENCE REVIEWS LA English DT Review ID HELIOSPHERIC MAGNETIC-FIELD; RECURRENT SOLAR MODULATION; MERGED INTERACTION REGIONS; HELIOGRAPHIC LATITUDE; INNER HELIOSPHERE; JOVIAN ELECTRONS; PARTICLE EVENTS; 3 DIMENSIONS; PROPAGATION; SIMULATION AB CIRs produce clearly visible recurrent modulation in the intensity of cosmic rays and anomalous components, but are not principally responsible for determining the overall global level of modulation. However, the localized variations imposed by CIRs in the parameters for propagation of energetic particles through the solar wind provide useful diagnostics for testing models of the propagation against observations. A principal result from Ulysses observations of CIR-induced variations is that the variations persist to very high latitudes, well beyond the range where CIRs are observed. This has driven theoretical models to provide for enhanced latitude transport of energetic particles. On the other hand, observations of Jovian electron intensities vs. latitude do not support enhanced latitude transport. This chapter contains a summary of the interaction between observations and models for the effects of CIRs, and its impact on the understanding of the physics of modulation. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Arizona, Dept Astron, Tucson, AZ USA. Potchefstroom Univ Christian Higher Educ, ZA-2520 Potchefstroom, South Africa. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Univ Milan, Dipartimento Fis, Milan, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McKibben, RB (reprint author), Univ Chicago, Enrico Fermi Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. OI Richardson, Ian/0000-0002-3855-3634 NR 45 TC 20 Z9 20 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 307 EP 326 DI 10.1023/A:1005222112325 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200015 ER PT J AU Mason, GM Von Steiger, R Decker, RB Desai, MI Dwyer, JR Fisk, LA Gloeckler, G Gosling, JT Hilchenbach, M Kallenbach, R Keppler, E Klecker, B Kunow, H Mann, G Richardson, IG Sanderson, TR Simnett, GM Wang, YM Wimmer-Schweingruber, RF Franz, M Mazur, JE AF Mason, GM Von Steiger, R Decker, RB Desai, MI Dwyer, JR Fisk, LA Gloeckler, G Gosling, JT Hilchenbach, M Kallenbach, R Keppler, E Klecker, B Kunow, H Mann, G Richardson, IG Sanderson, TR Simnett, GM Wang, YM Wimmer-Schweingruber, RF Franz, M Mazur, JE CA Working Grp 6 TI Origin, injection, and acceleration of CIR particles: Observations - Report of Working Group 6 SO SPACE SCIENCE REVIEWS LA English DT Review ID COROTATING INTERACTION REGIONS; ROTATING INTERACTION REGIONS; HIGH HELIOGRAPHIC LATITUDES; SOLAR-WIND STREAM; EARTHS BOW SHOCK; MAGNETIC-FIELD; ENERGETIC PARTICLES; ULYSSES OBSERVATIONS; ECLIPTIC-PLANE; IONS UPSTREAM AB This report emphasizes new observational aspects of CIR ions revealed by advanced instruments launched on the Ulysses, WIND, SOHO, and ACE spacecraft, and by the unique vantage point of Ulysses which carried out the first survey of Corotating Interaction Region (CIR) properties over a very wide range of heliolatitudes. With this more complete observational picture established, this review is the basis to consider the status of theoretical models on origin, injection, and acceleration of CIR particles reported by Scholer, Mann et al. (1999) in this volume. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Int Space Sci Inst, Bern, Switzerland. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Univ Michigan, Dept Atmospher & Space Sci, Ann Arbor, MI 48109 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Univ Kiel, Kiel, Germany. Inst Astrophys, Potsdam, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ESA, ESTEC, Dept Space Sci, Noordwijk, Netherlands. Univ Birmingham, Dept Phys & Astron, Birmingham, W Midlands, England. USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. Univ Bern, Inst Phys, Bern, Switzerland. Queen Mary Univ London, London E1 4NS, England. Aerosp Corp, Los Angeles, CA 90009 USA. RP Mason, GM (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. EM Glenn.Mason@umail.umd.edu; vonsteiger@issi.unibe.ch; robert.decker@jhuapl.edu; desai@uleiss.umd.edu; dwyer@uleis.umd.edu; lafisk@umich.edu; gg10@pop.umail.umd.edu; jgosling@lan1.gov; hilchenbach@roland4.mpae.gwdg.de; kallenbach@issi.unibe.ch; keppler@pgate2.mpae.gwdg.de; bek@mpesmp.mpe-garching.mpg.de; kunow@kernphysik.uni-kiel.de; gmann@aip.de; richardson@lheavx.gsfc.nasa.gov; sanderson@estso3.estec.esa.nl; gms@star.sr.bham.ac.uk; ywang@yucca.nrl.navy.mil; wimmer@phim.unibe.ch RI Von Steiger, Rudolf/F-6822-2011; OI Von Steiger, Rudolf/0000-0002-3350-0023; Richardson, Ian/0000-0002-3855-3634 NR 65 TC 29 Z9 29 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 89 IS 1-2 BP 327 EP 367 DI 10.1023/A:1005278214143 PG 41 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 286AV UT WOS:000085422200016 ER PT J AU Gonzalez, WD Tsurutani, BT De Gonzalez, ALC AF Gonzalez, WD Tsurutani, BT De Gonzalez, ALC TI Interplanetary origin of geomagnetic storms SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND; MAGNETIC CLOUDS; ALFVEN WAVES; CORONAL HOLES; ULYSSES OBSERVATIONS; INTERACTION REGIONS; VISCOUS INTERACTION; COMPOUND STREAMS; CURRENT SHEET; PLASMA SHEET AB Around solar maximum, the dominant interplanetary phenomena causing intense magnetic storms (Dst <-100 nT) are the interplanetary manifestations of fast coronal mass ejections (CMEs). Two interplanetary structures are important for the development of storms, involving intense southward IMFs: the sheath region just behind the forward shock, and the CME ejecta itself. Whereas the initial phase of a storm is caused by the increase in plasma ram pressure associated with the increase in density and speed at and behind the shock (accompanied by a sudden impulse [SI] at Earth), the storm main phase is due to southward IMFs. If the fields are southward in both of the sheath and solar ejecta, two-step main phase storms can result and the storm intensity can be higher. The storm recovery phase begins when the IMF turns less southward, with delays of approximate to 1-2 hours, and has typically a decay time of 10 hours. For CMEs involving clouds the intensity of the core magnetic field and the amplitude of the speed of the cloud seems to be related, with a tendency that clouds which move at higher speeds also posses higher core magnetic field strengths, thus both contributing to the development of intense storms since those two parameters are important factors in genering the solar wind-magnetosphere coupling via the reconnection process. During solar minimum, high speed streams from coronal holes dominate the interplanetary medium activity. The high-density, low-speed streams associated with the heliospheric current sheet (HCS) plasma impinging upon the Earth's magnetosphere cause positive Dst values (storm initial phases if followed by main phases). In the absence of shocks, SIs are infrequent during this phase of the solar cycle. High-field regions called Corotating Interaction Regions (CIRs) are mainly created by the fast stream (emanating from a coronal hole) interaction with the HCS plasma sheet. However, because the B-z component is typically highly fluctuating within the CIRs, the main phases of the resultant magnetic storms typically have highly irregular profiles and are weaker. Storm recovery phases during this phase of the solar cycle are also quite different in that they can last from many days to weeks. The southward magnetic field (B-s) component of Alfven waves in the high speed stream proper cause intermittent reconnection, intermittent substorm activity, and sporadic injections of plasma sheet energy into the outer portion of the ring current, prolonging its final decay to quiet day values. This continuous auroral activity is called High Intensity Long Duration Continuous AE Activity (HILDCAAs). Possible interplanetary mechanisms for the creation of very intense magnetic storms are discussed. We examine the effects of a combination of a long-duration southward sheath magnetic field, followed by a magnetic cloud B-s event. We also consider the effects of interplanetary shock events on the sheath plasma. Examination of profiles of very intense storms from 1957 to the present indicate that double, and sometimes triple, IMF B-s events are important causes of such events. We also discuss evidence that magnetic clouds with very intense core magnetic fields tend to have large velocities, thus implying large amplitude interplanetary electric fields that can drive very intense storms. Finally, we argue that a combination of complex interplanetary structures, involving in rare occasions the interplanetary manifestations of subsequent CMEs, can lead to extremely intense storms. C1 Inst Nacl Pesquisas Espaciais, Sao Paulo, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Gonzalez, WD (reprint author), Inst Nacl Pesquisas Espaciais, Sao Paulo, Brazil. NR 86 TC 262 Z9 272 U1 5 U2 32 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 88 IS 3-4 BP 529 EP 562 DI 10.1023/A:1005160129098 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 237VG UT WOS:000082676400003 ER PT J AU Burlaga, LF Szabo, A AF Burlaga, LF Szabo, A TI Fast and slow flows in the solar wind near the ecliptic at 1 AU? SO SPACE SCIENCE REVIEWS LA English DT Review ID MAGNETIC-FIELD; CORONAL STREAMERS; PLASMA; 1-AU AB At 1 AU in 1998, when solar activity was increasing, the distribution of hour averages of the solar wind speed was approximately lognormal. There was no distinct separation between fast and slow flows. The density, temperature and magnetic field strength also had lognormal distributions. It was possible to identify distinct structures such as corotating streams and magnetic clouds during some intervals. We suggest that coexistence of a simple statistical structure and deterministic physical structures is the consequence of the dynamical evolution and interactions of the flows between the sun and 1 AU and a relatively complex source signal. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 692, Greenbelt, MD 20771 USA. NR 13 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 137 EP 140 DI 10.1023/A:1005186720589 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000013 ER PT J AU Davila, JM Ofman, L AF Davila, JM Ofman, L TI Two-fluid 2.5D MHD simulations of the fast solar wind in coronal holes and the relation to UVCS observations SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLITARY WAVES; ACCELERATION AB Recent SOHO/UVCS observations indicate that the perpendicular proton and ion temperatures are much larger than electron temperatures. In the present study we simulate numerically the solar wind flow in a coronal hole with the two-fluid approach. We investigate the effects of electron and proton temperatures on the solar wind acceleration by nonlinear waves. In the model the nonlinear waves are generated by Alfven waves with frequencies in the 10(-3) Hz range, driven at the base of the coronal hole. The resulting electron and proton flow profile exhibits density and velocity fluctuations. The fluctuations may steepen into shocks as they propagate away from the sun. We calculate the effective proton temperature by combining the thermal and wave velocity of the protons, and find qualitative agreement with the proton kinetic temperature increase with height deduced from the UVCS Ly-alpha observations by Kohl et al. (1998). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 165 EP 168 DI 10.1023/A:1005155209202 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000020 ER PT J AU Dobrzycka, D Strachan, L Miralles, MP Kohl, JL Gardner, LD Smith, P AF Dobrzycka, D Strachan, L Miralles, MP Kohl, JL Gardner, LD Smith, P TI Variation of polar coronal hole profiles with solar cycle SO SPACE SCIENCE REVIEWS LA English DT Review DE corona; coronal holes; line profiles AB We compared the H I Ly alpha polar coronal hole profiles obtained during the three Spartan 201 flights (in 1993, 1994, and 1995) and during the more recent UVCS/SOHO mission. We found that at 2.1 R. there are no significant variations of the line shape over the several years of the descending phase of the solar cycle. However, there may be some evidence for the 1.8 R. profiles being broader towards solar minimum. The profiles at 2.1 R. are different from profiles obtained at 1.8 R.; they have clearly narrower cores and wide wings. We fitted the profiles with single and/or multiple Gaussian functions and calculated their typical 1/e half widths. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Copernicus Astron Ctr, PL-00716 Warsaw, Poland. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 50, Cambridge, MA 02138 USA. EM ddobrzycka@cfa.harvard.edu NR 7 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 177 EP 180 DI 10.1023/A:1005171728767 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000023 ER PT J AU Falconer, DA Moore, RL Porter, JG Hathaway, DH AF Falconer, DA Moore, RL Porter, JG Hathaway, DH TI Large-scale coronal heating, clustering of coronal bright points, and concentration of magnetic flux SO SPACE SCIENCE REVIEWS LA English DT Review DE coronal heating; magnetic network; coronal bright points AB By combining quiet-region Fe MI coronal images from SOHO/EIT with magnetograms from NSO/Kitt Peak and from SOHO/MDI, we show that the population of network coronal bright points and the magnetic flux content of the network are both markedly greater under the bright half of the large-scare quiet corona than under the dim half. These results (I) support the view that the heating of the entire corona in quiet regions and coronal holes is driven by fine scale magnetic activity (microflares, explosive events, spicules) seated low in the magnetic network, and (2) suggest that this large-scale modulation of the magnetic flux and coronal heating is a signature of giant convection cells. C1 NASA, George C Marshall Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, George C Marshall Space Flight Ctr, Greenbelt, MD 20771 USA. EM falcoda@ips1.msfc.nasa.gov NR 3 TC 3 Z9 3 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 181 EP 184 DI 10.1023/A:1005175812837 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000024 ER PT J AU Fludra, A Del Zanna, G Bromage, BJI AF Fludra, A Del Zanna, G Bromage, BJI TI EUV observations above polar coronal holes SO SPACE SCIENCE REVIEWS LA English DT Review DE solar corona; coronal holes; electron temperature; electron density AB We derive electron temperature and density as a function of height up to 0.2 R. above the limb in polar coronal holes, using five EUV data sets recorded by the SOHO Coronal Diagnostic Spectrometer between July 1997 and February 1998. Radial T-e and N-e distributions, averaged in a 2 degrees to 10 degrees range of position angles, are the same above the North and South coronal holes. They do not show any time variability over a period of seven months. Polar plumes are found to have lower electron temperature and higher density than the interplume lanes. The electron density slope suggests that the proton temperatures are twice as high as the electron temperatures. C1 Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Cent Lancashire, Preston PR1 2HE, Lancs, England. RP NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. NR 5 TC 15 Z9 15 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 185 EP 188 DI 10.1023/A:1005127930584 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000025 ER PT J AU Guhathakurta, M Sittler, EC McComas, D AF Guhathakurta, M Sittler, EC McComas, D TI Semi-empirical MHD model of the solar wind and its comparison with Ulysses SO SPACE SCIENCE REVIEWS LA English DT Review ID CORONA; PARAMETERS; DISRUPTION AB We have developed a 2D semi-empirical model (Sittler and Guhathakurta 1999) of the corona and the interplanetary medium using the time independent MHD equations and assuming azimuthal symmetry, utilizing the SOHO, Spartan and Ulysses observations. The model uses as inputs (1) an empirically derived global electron density distribution using LASCO, Mark III and Spartan white light observations and in situ observations of the Ulysses spacecraft, and (2) an empirical model of the coronal magnetic field topology using SOHO/LASCO and EIT observations. The model requires an estimate of solar wind velocity as a function of latitude at 1 AU and the radial component of the magnetic field at 1 AU, for which we use Ulysses plasma and magnetic field data results respectively. The model makes estimates as a function of radial distance and latitude of various fluid parameters of the plasma such as flow velocity V, temperature T-eff, and heat flux Q(eff) which are derived from the equations of conservation of mass, momentum and energy, respectively, in the rotating frame of the Sun. The term "effective" indicates possible wave contributions. The model can be used as a planning tool for such missions as Solar Probe and provide an empirical framework for theoretical models of the salar corona and salar wind. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. LANL, Los Alamos, NM USA. RP NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. EM lika@tristang.gsfc.nasa.gov NR 18 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 199 EP 206 DI 10.1023/A:1005140232401 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000028 ER PT J AU Insley, JE AF Insley, JE TI A CDS observation of the relationship between a coronal hole and chromospheric structure SO SPACE SCIENCE REVIEWS LA English DT Review ID WIND AB This paper studies the relationship between chromospheric structure and the location of the coronal hole boundary, using a SOHO-CDS observation made on 13 June 1996. The cell structure visible in the oxygen and helium data is smoothed and a basin algorithm is used to find the individual cells. As the smoothing scale increases, cells merge to form larger ones. A trade off between merging and smoothing was made, a scale of 5,000 km being used. There is good agreement between the edges of cells and the coronal hole boundary, as determined in Mg IX 368 Angstrom, although it is not perfect. This preliminary analysis shows that the coronal hole boundary is located along chromospheric network cell edges in most places, as would be expected if the chromosphere is the source of the coronal structure and solar wind. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 215 EP 218 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000031 ER PT J AU Ko, YK Groth, CPT AF Ko, YK Groth, CPT TI On the electron temperature and coronal heating in the fast solar wind constrained by in-situ observations SO SPACE SCIENCE REVIEWS LA English DT Review ID 1 AU; HOLE; DYNAMICS; MODEL AB The electron temperature profile in the polar coronal hole inferred by the ionic charge state data of the fast wind exhibits a local maximum of similar to 1.5 x 10(6) K. This indicates the existence of electron heating in the source region of the fast solar wind. In this paper, a two-fluid solar wind model, which incorporates additional 'mechanical' heating, is used to investigate the heating of the electrons in the coronal hole. We find that the classical collision-dominated description for the electron conduction heat flux is not valid and needs to be severely limited in order for the electron temperatures predicted by the model to agree with constraints supplied by both the solar wind ionic charge state data and the solar wind plasma properties observed at 1 AU. The corresponding constraints on the coronal electron heating will also be discussed. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. EM kuen@uvcs14.nascom.nasa.gov NR 18 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 227 EP 231 DI 10.1023/A:1005104719197 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000034 ER PT J AU Liewer, P Velli, M Goldstein, B AF Liewer, P Velli, M Goldstein, B TI Hybrid simulations of wave propagation and ion cyclotron heating in the expanding solar wind SO SPACE SCIENCE REVIEWS LA English DT Review AB We present results from hybrid (particle ions, fluid electrons) simulations of the evolution of Alfven waves close to the ion cyclotron frequency in the solar wind, which take into account the basic properties of the background solar wind how, i.e., the spherical expansion and the consequent decrease in magnetic field and cyclotron frequency with increasing distance from the Sun. We follow the evolution of a plasma parcel in a frame of reference moving with the solar wind using a 1D expanding box hybrid model; use of the hybrid model yields a fully self-consistent treatment of the resonant cyclotron wave-particle interaction. This model is related to a previous MHD model (Velli et al. 1992), which allows the use of a simple Cartesian geometry with periodic boundary conditions. The use of stretched expanding coordinates in directions transverse to the mean radial solar wind flow naturally introduces an anisotropic damping effect on velocity and magnetic field. We present results for the case of a single circularly polarized Alfven wave propagating radially outward. Initially, the wave is below the cyclotron frequency for both the alpha particles and protons. As the wind expands, the wave frequency (as seen in the solar wind frame) decreases more slowly than the cyclotron frequencies and the wave comes into resonance. With only protons, heating occurs as the wave frequency approaches the proton cyclotron frequency. With both alphas and protons, the alphas, which come into resonance first, are observed to be preferentially heated and accelerated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 257 EP 260 DI 10.1023/A:1005169005993 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000041 ER PT J AU Miralles, MP Strachan, L Gardner, LD Smith, PL Kohl, JL Guhathakurta, M Fisher, RR AF Miralles, MP Strachan, L Gardner, LD Smith, PL Kohl, JL Guhathakurta, M Fisher, RR TI Properties of coronal hole/streamer boundaries and adjacent regions as observed by Spartan 201 SO SPACE SCIENCE REVIEWS LA English DT Review ID EXTENDED SOLAR CORONA; WIND; STREAMERS; ORIGINS AB The Spartan 201 flights from 1993 to 1995 provided us with observations in H I Lyman-alpha of several coronal hole/streamer boundaries and adjacent streamers during the declining phase of the current solar cycle. Analysis of the latitudinal dependence of the line intensities clearly shows that there is a boundary region at the coronal hole/streamer interface where the H I Lyman-alpha intensity reaches a minimum value. Similar results are also found in UVCS/SOHO observations. We also discuss differences in the coronal hole/streamer boundaries for different types of streamers and their changes over the three year period of Spartan 201 observations. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 50, Cambridge, MA 02138 USA. EM mmiralles@cfa.harvard.edu NR 13 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 277 EP 281 DI 10.1023/A:1005177207810 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000045 ER PT J AU Moore, RL Falconer, DA Porter, JG Suess, ST AF Moore, RL Falconer, DA Porter, JG Suess, ST TI Coronal heating by magnetic explosions SO SPACE SCIENCE REVIEWS LA English DT Review DE coronal heating; magnetic field; magnetic shear; magnetic explosion ID NETWORK; PLUMES AB From magnetic fields and coronal heating observed in flares, active regions, quiet regions, and coronal holes, we propose that exploding sheared core magnetic fields are the drivers of most of the dynamics and heating of the solar atmosphere, ranging from the largest and most powerful coronal mass ejections and flares, to the vigorous microflaring and coronal heating in active regions, to a multitude of fine-scale explosive events in the magnetic network, driving microflares, spicules, global coronal heating, and, consequently, the solar wind. C1 NASA, George C Marshall Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, George C Marshall Space Flight Ctr, Greenbelt, MD 20771 USA. EM ron.moore@msfc.nasa.gov NR 19 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 283 EP 286 DI 10.1023/A:1005129424649 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000046 ER PT J AU Ofman, L Romoli, M Noci, G Poletto, G Kohl, JL Howard, RA St Cyr, C Deforest, CE AF Ofman, L Romoli, M Noci, G Poletto, G Kohl, JL Howard, RA St Cyr, C Deforest, CE TI SOHO observations of density fluctuations in coronal holes SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND ACCELERATION; SOLITARY WAVES; SPECTROMETER AB In recent UVCS/SOHO White Light Channel (WLC) observations we found quasi-periodic variations in the polarized brightness (pB) in the polar coronal holes at heliocentric distances of 1.9 to 2.45 solar radii. The motivation for the observation is the 2.5D MHD model of solar wind acceleration by nonlinear waves, that predicts compressive fluctuations in coronal holes. in February 1998 we performed new observations using the UVCS/WLC in the coronal hole and obtained additional data. The new data corroborate our earlier findings with higher statistical significance. The new longer observations show that the power spectrum peaks in the 10-12 minute range. These timescales agree with EIT observations of brightness fluctuations in polar plumes. We performed preliminary LASCO/C2 observations in an effort to further establish the coronal origin of the fluctuations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS, Greenbelt, MD 20771 USA. Univ Florence, Dept Astron, I-50125 Florence, Italy. Osserv Astrofis Arcetri, I-50125 Florence, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. USN, Res Lab, Washington, DC 20375 USA. Stanford Univ, Stanford, CA 94305 USA. RP NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. RI Romoli, Marco/H-6859-2012 NR 9 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 287 EP 290 DI 10.1023/A:1005181408719 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000047 ER PT J AU Strachan, L Ko, YK Panasyuk, AV Dobrzycka, D Kohl, JL Romoli, M Noci, G Gibson, SE Biesecker, DA AF Strachan, L Ko, YK Panasyuk, AV Dobrzycka, D Kohl, JL Romoli, M Noci, G Gibson, SE Biesecker, DA TI Constraints on coronal outflow velocities derived from UVCS Doppler dimming measurements and in-situ charge state data SO SPACE SCIENCE REVIEWS LA English DT Review DE corona; solar wind; UV radiation; spectroscopy; line profiles ID HOLE AB We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Angstrom emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 solar radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the first Whole Sun Month Campaign (10 August to 8 September 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from 'freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on neutral hydrogen outflow velocities which depend on modeling the absolute coronal H I Ly alpha emissivities. We use an iterative method to determine the neutral hydrogen outflow velocity with consistent values for the electron temperatures derived from a freezing-in model. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Florence, I-50125 Florence, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Catholic Univ Amer, Washington, DC 20064 USA. RP Harvard Smithsonian Ctr Astrophys, 60 Garden St,Mail Stop 50, Cambridge, MA 02138 USA. EM lstrachan@cfa.harvard.edu RI Gibson, Sarah/A-9189-2011; Romoli, Marco/H-6859-2012 NR 7 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 311 EP 314 DI 10.1023/A:1005193711445 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000053 ER PT J AU Suess, ST Poletto, G Corti, G Simnett, G Noci, G Romoli, M Kohl, J Goldstein, B AF Suess, ST Poletto, G Corti, G Simnett, G Noci, G Romoli, M Kohl, J Goldstein, B TI Ulysses-UVCS coordinated observations SO SPACE SCIENCE REVIEWS LA English DT Review DE SOHO; Ulysses; streamers AB We present results from SOHO/UVCS measurements of the density and flow speed of plasma at the Sun and again of the same plasma by Ulysses/SWOOPS in the solar wind. UVCS made measurements at 3.5 and 4.5 solar radii and Ulysses was at 5.1 AU. Data were taken for nearly 2 weeks in May-June 1997 at 9-10 degrees north of the equator in the streamer belt on the east limb. Density and flow speed were compared to see if near Sun characteristics are preserved in the interplanetary medium. By chance, Ulysses was at the very northern edge of the streamer belt. Nevertheless, no evidence was found of fast wind or mixing of slow wind with fast wind coming from the northern polar coronal hole. The morphology of the streamer belt was similar at the beginning and end of the observing period, but was markedly different during the middle of the period. A corresponding change in density (but not flow speed) was noted at Ulysses. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Univ Florence, I-50121 Florence, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP NASA, George C Marshall Space Flight Ctr, Mail Stop ES82, Huntsville, AL 35812 USA. RI Romoli, Marco/H-6859-2012 NR 2 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 319 EP 322 DI 10.1023/A:1005197812354 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000055 ER PT J AU Suess, ST Wang, AH Wu, ST AF Suess, ST Wang, AH Wu, ST TI Streamer evaporation SO SPACE SCIENCE REVIEWS LA English DT Review DE corona; streamers; magnetohydrodynamics ID CORONA AB Streamer evaporation is the consequence of heating in ideal MHD models because plasma is weakly contained by the magnetic field. Heating causes inflation, opening of field lines, and release of solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because of tosses by thermal conduction and radiation. Heating is also expected to depend on ambient conditions. We use a global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than similar to 2 X 10(6) K. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Ohio Univ, Lancaster, OH 43130 USA. RP NASA, George C Marshall Space Flight Ctr, Mail Stop ES82, Huntsville, AL 35812 USA. NR 7 TC 7 Z9 7 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 323 EP 326 DI 10.1023/A:1005149929192 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000056 ER PT J AU Velli, M Liewer, P AF Velli, M Liewer, P TI Alfven wave generation in photospheric vortex filaments, macrospicules, and "solar tornadoes" SO SPACE SCIENCE REVIEWS LA English DT Review ID ATMOSPHERE; CHROMOSPHERE; ACCELERATION; PROPAGATION AB The properties of Alfven waves generated in the photosphere by field lines trapped in vortex sinks and propagating upwards through the transition region and corona are discussed and contrasted to those of waves generated via reconnection in transition region explosive events, or rather via untwisting reconnecting flux tubes. An outline for future simulations and theoretical advances necessary to understand the dynamics of spicules and macrospicules is described, and a detailed search for photospheric velocity patterns underlying macrospicules is suggested. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 12 Z9 12 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1999 VL 87 IS 1-2 BP 339 EP 343 DI 10.1023/A:1005110315988 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 239YL UT WOS:000082798000060 ER PT S AU Penley, N Schafer, CP Eppler, DB Gavalas, J McEwen, MC Voels, SA AF Penley, N Schafer, CP Eppler, DB Gavalas, J McEwen, MC Voels, SA BE ElGenk, MS TI An overview of International Space Station utilization preparation and planning SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station (ISS) is being designed and constructed to support the investigational needs of a wide range of research disciplines: Microgravity; Life Sciences; Earth and Space Sciences; Commercialization; and Engineering Research and Technology. In addition to the payloads being developed for specific, targeted research investigations, there are also a number of multi-user/facility class payloads being developed which will be capable of supporting a wide range of investigators and their investigations. One of the challenges for the ISS Program is integrating the research needs, payloads and facilities of these research disciplines into a cohesive research program which will optimize the research potential of the ISS. The Research Mission Management Office will be responsible for ensuring that the research priorities are determined and reflected in the execution of the research on the ISS. C1 NASA, Lyndon B Johnson Space Ctr, Res Mission Management Off, Houston, TX 77058 USA. RP Penley, N (reprint author), NASA, Lyndon B Johnson Space Ctr, Res Mission Management Off, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 19 EP 24 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200002 ER PT S AU Hartman, DW AF Hartman, DW BE ElGenk, MS TI International Space Station payload accommodations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station (ISS) is a low Earth orbiting facility for conducting research in life science, microgravity, Earth observations, and Engineering Research and Technology. Assembled on-orbit at an nominal altitude of 220 nautical miles, it will provide a shirt-sleeve environment for conducting research in six laboratories: the US Laboratory (US Lab), the Japanese Experiment Module (JEM), the European Columbus Orbiting Facility (COF), the Centrifuge Accommodations Module (CAM), and the Russian Research Modules. Supplies will be replenished using the Multi-Purpose Pressurized Logistics Module (MPLM), a conditioned pressurized transport carrier which will also return passive and perishable payload cargo to earth. External Earth observations can be performed by utilizing the payload attachment points on the truss, the Russian Science Power Platform, the JEM Exposed Facility (EF), and the COF backporch. The pressurized and external locations are equipped with a variety of electrical, avionics, fluids, and gas interfaces to support the experiments. ISS solar arrays, thermal radiators, communication system, propulsion, environmental control, and robotic devices provide the infrastructure to support sustained research. This paper, which reflects the design maturity of payload accommodations at the time of its submittal (10/20/98), is primarily based on the assembly complete configuration of the station. As the design matures, ISS Payload Accommodations will be updated to reflect qualification tests of components and associated analyses of the integrated performance. C1 NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, Houston, TX 77058 USA. RP Hartman, DW (reprint author), NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, OZ3, Houston, TX 77058 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 25 EP 30 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200003 ER PT S AU Cook, G AF Cook, G BE ElGenk, MS TI International Space Station attached payload overview SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station is being designed as a research platform for science to be conducted inside the pressurized volume and also to conduct science with experiments attached to the structure externally. This paper describes the various accommodations for the conduct of external science and the facilities available for the deployment and servicing of external payloads. The paper also addresses the plans for monitoring the external environment of the Space Station in support of external science objectives. C1 NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, Houston, TX 77058 USA. RP Cook, G (reprint author), NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, OZ3, Houston, TX 77058 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 31 EP 36 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200004 ER PT S AU Scheib, JS AF Scheib, JS BE ElGenk, MS TI Payload integration process SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB This paper contains a general description of the National Aeronautics and Space Administration (NASA) Space Station Payloads Office (SSPO) integration process for International Space Station (ISS) payloads. The end-to-end process described herein covers the strategic, tactical, execute preparation, real-time operations and post-flight phases of payload integration. Challenges that complicate the development of an integration process include the combination of the on-orbit and transportation integration activities, inclusion of the International Partner (IP) launch vehicles and accommodations, and the requirement to integrate these activities across different organizations and field centers. The paper describes the necessary agreements, plans, documents and reviews required to integrate and operate payloads into standard payload locations. It also summarizes the Program boards, panels and points of contact that a Payload Developer (PD) will participate in or interface with during the course of the process. The purpose is to provide potential PDs with an outline of the SSPO processes to deliver payloads to orbit, conduct science experiments on orbit and return them to Earth. C1 NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, Houston, TX 77058 USA. RP Scheib, JS (reprint author), NASA, Lyndon B Johnson Space Ctr, Int Space Stn, Program Off,Payloads Off, OZ2, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 37 EP 42 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200005 ER PT S AU Cissom, RD Melton, TL Lapenta, CC Schneider, MP AF Cissom, RD Melton, TL Lapenta, CC Schneider, MP BE ElGenk, MS TI Payload operations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The objective of this paper is to provide future International Space Station (ISS) scientists and/or engineers with a feel for ISS payload operations by presenting a real-time scenario. This scenario begins at the initiation of payload operations and runs through immediate post-run experiment analysis. In developing this scenario, it is assumed that the ISS payload operations flight and ground capabilities are fully available for use by the payload user community. Emphasis is placed on telescience operations whose main objective is to enable researchers to utilize experiment hardware onboard the International Space Station as if it were located in their terrestrial laboratory. An overview of the Payload Operations Integration Center (POIC) systems and user ground system options is included to provide an understanding of the systems and interfaces available to perform payload operations. Detailed information regarding POIC capabilities can be found in the POIC Capabilities Document, SSP 50304. C1 NASA, Lyndon B Johnson Space Ctr, OZ, Houston, TX 77058 USA. RP Cissom, RD (reprint author), NASA, Lyndon B Johnson Space Ctr, OZ, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 43 EP 48 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200006 ER PT S AU Carruth, R Clifton, KS AF Carruth, R Clifton, KS BE ElGenk, MS TI An environment monitoring package for the International Space Station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The first elements of the International Space Station (ISS) will soon be launched into space and over the next few years ISS will be assembled on orbit into its final configuration. Experiments will be performed on a continuous basis both inside and outside the station. External experiments will be mounted on attached payload locations specifically designed to accommodate experiments, provide data and supply power from ISS. From the beginning of the space station program it has been recognized that experiments will require knowledge of the external local environment which can affect the science being performed and may impact lifetime and operations of the experiment hardware. Recently an effort was initiated to design and develop an Environment Monitoring Package (EMP). This paper describes the derivation of the requirements for the EMP package, the type of measurements that the EMP will make and types of instruments which will be employed to make these measurements. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Carruth, R (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 64 EP 69 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200009 ER PT S AU Primm, L Bergmann, A AF Primm, L Bergmann, A BE ElGenk, MS TI EXPRESS service to the International Space Station: EXPRESS Pallet SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station (ISS) will be the ultimate scientific accomplishment in the history of NASA, with its primary objective of providing unique scientific investigation opportunities. This objective is the basis for the creation of the EXPRESS Pallet System (ExPS). The EXPRESS Pallet will provide external/unpressurized accommodations for a wide variety of external users. The payload developers represent many science disciplines, including earth observation, communications, solar and deep space viewing, long-term exposure, and many others. The EXPRESS Pallet will provide a mechanism to maximum utilization of the limited ISS unpressurized payload volume, standard physical payload interfaces for users, a standard integration template for users and the capability to changeout payloads on-orbit. The EXPRESS Pallet provides access to Ram, Wake, Starboard, Pea, Nadir, Zenith and Earth Limb for exposure and viewing. The ExPs consists of the Pallet structure, payload Adapters, and a subsystem assembly which includes data controller, power distribution and conversion, and Extra Vehicular Robotics/Extra-Vehicular Activity systems. C1 NASA, George C Marshall Space Flight Ctr, Space Stn, Utilizat Off, Huntsville, AL 35812 USA. RP Primm, L (reprint author), NASA, George C Marshall Space Flight Ctr, Space Stn, Utilizat Off, Mail Code JA62, Huntsville, AL 35812 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 76 EP 81 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200011 ER PT S AU Weiland, KJ AF Weiland, KJ BE ElGenk, MS TI Combustion studies aboard the International Space Station: Planned experiments and facilities SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID MICROGRAVITY AB The Fluids and Combustion Facility (FCF) is a payload planned for the International Space Station. The facility is designed to accommodate a wide variety of investigations encompassing the range of microgravity fluid physics and combustion science. The combustion areas that may be studied include laminar flames, reaction kinetics, droplet and spray combustion, flame spread, fire and fire suppressants, condensed phase organic fuel combustion, turbulent combustion, soot and polycyclic aromatic hydrocarbons, materials synthesis, and detonations and explosions. The initial experiments will study droplet combustion and solid fuel flammability, ignition, and transition to flame spread. The Combustion Integrated Rack component of the FCF is currently scheduled to be launched in 2002 and will operate independently until the FCF is complete in 2003. The FCF is intended to complete between five and fifteen combustion experiments per year over its planned ten-year lifetime. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Weiland, KJ (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 110-3, Cleveland, OH 44135 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 82 EP 87 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200012 ER PT S AU Singh, BS AF Singh, BS BE ElGenk, MS TI Fluid physics and transport phenomena studies aboard the International Space Station: Planned experiments SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB This paper provides an overview of the microgravity fluid physics and transport phenomena experiments planned for the International Space Station. NASA's Office of Life and Microgravity Science and Applications has established a world-class research program in fluid physics and transport phenomena. This program combines the vast expertise of the world research community with NASA's unique microgravity facilities with the objectives of gaining new insight into fluid phenomena by removing the confounding effect of gravity. Due to its criticality to many terrestrial and space-based processes and phenomena, fluid physics and transport phenomena play a central role in the NASA's Microgravity Program. Through widely publicized research announcement and well established peer-reviews, the program has been able to attract a number of world-class researchers and acquired a critical mass of investigations that is now adding rapidly to this field. Currently there are a total of 106 ground-based and 20 candidate flight principal investigators conducting research in four major thrust areas in the program: complex flows, multiphase flow and phase change, interfacial phenomena, and dynamics and instabilities. The international Space Station (ISS) to be launched in 1998, provides the microgravity research community with a unprecedented opportunity to conduct long-duration microgravity experiments which can be controlled and operated from the Principal Investigators' own laboratory. Frequent planned shuttle flights to the Station will provide opportunities to conduct many more experiments than were previously possible. NASA Lewis Research Center is in the process of designing a Fluids and Combustion Facility (FCF) to be located in the Laboratory Module of the ISS that will not only accommodate multiple users but allow a broad range of fluid physics and transport phenomena experiments to be conducted in a cost effective manner. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Singh, BS (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 100 EP 107 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200015 ER PT S AU Jones, WV AF Jones, WV BE ElGenk, MS TI The International Space Station as an observatory for cosmic-ray physics and astrophysics SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station is an ideal platform for observing cosmic rays. Furthermore, it can readily accommodate the instrumentation needed to address all of the top-priority science objectives identified in 1995 by the National Academy of Sciences for "Plasma Processes that Accelerate Very Energetic Particles and Control Their Propagation." These objectives are synergistic in their pursuit of the illusive goal of understanding the origin, acceleration, and propagation of the cosmic radiation. A distributed observatory on the International Space Station may be the key to answering this long-standing question in the first decade of the new millennium. C1 NASA, Off Space Sci, Code SR, Washington, DC 20546 USA. RP Jones, WV (reprint author), NASA, Off Space Sci, Code SR, Washington, DC 20546 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 133 EP 138 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200020 ER PT S AU Kaye, JA AF Kaye, JA BE ElGenk, MS TI The role of the Space Station in earth science research SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID STRATOSPHERIC-AEROSOL; TECHNOLOGY EXPERIMENT; SHUTTLE MISSIONS; LITE AB The International Space Station (ISS) has the potential to be a valuable platform for earth science research. By virtue of its being in a mid-inclination orbit (51.5 degrees), ISS provides the opportunity for nadir viewing of nearly 3/4 of the Earth's surface, and allows viewing to high latitudes if limb-emission or occultation viewing techniques are used. ISS also provides the opportunity for viewing the Earth under a range of lighting conditions, unlike the polar sun-synchronous satellites that are used for many earth observing programs. The ISS is expected to have ample power and data handling capability to support Earth-viewing instruments, provide opportunities for external mounting and retrieval of instruments, and be in place for a sufficiently long period that long-term data records can be obtained. On the other hand, there are several questions related to contamination, orbital variations, pointing knowledge and stability, and viewing that are of concern in consideration of ISS for earth science applications. The existence of an optical quality window (the Window Observational Research Facility, or WORE), also provides the opportunity for Earth observations from inside the pressurized part of ISS. Current plans by NASA for earth science research from ISS are built around the Stratospheric Aerosol and Gas Experiment (SAGE III) instrument, planned for launch in 2002. C1 NASA, Off Earth Sci, Washington, DC 20546 USA. RP Kaye, JA (reprint author), NASA, Off Earth Sci, Washington, DC 20546 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 139 EP 144 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200021 ER PT S AU Runco, SK Eppler, DB Scott, KP AF Runco, SK Eppler, DB Scott, KP BE ElGenk, MS TI The Space Station Window Observational Research Facility; a high altitude imaging laboratory SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Earth Science will be one of the major research areas to be conducted on the International Space Station. The facilities from which this research will be accomplished are currently being constructed and will be described in this paper. By April 1999, the International Space Station nadir viewing research window fabrication will be completed and ready for installation. The window will provide a 20 inch (51 cm) diameter clear aperture. The three fused silica panes, which make up the window are fabricated such that the total peak-to-valley wavefront error in transmission through the three panes over any six inch diameter aperture does not exceed lambda/7 where the reference wavelength is 632.8 nm. The window will have over 90 % transmission between about 400 and 750, above 50% transmission between about 310 nm and 1375 nm and 40% transmission between 1386 nm and 2000 nm. The Window Operational Research Facility (WORF) is designed to accommodate payloads using this research window. The WORF will provide access to the International Space Station utilities such as data links, temperature cooling loops and power. Emphasis has been placed on the factors which will make this facility an optimum platform for conducting Earth science research. C1 NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Houston, TX 77058 USA. RP Runco, SK (reprint author), NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Code SN3, Houston, TX 77058 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 151 EP 156 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200023 ER PT S AU Peele, AG Zhang, W Gendreau, KC Petre, R White, NE AF Peele, AG Zhang, W Gendreau, KC Petre, R White, NE BE ElGenk, MS TI A lobster-eye on the x-ray sky SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID CHANNEL-CAPILLARY ARRAYS; MONITOR; OPTICS AB We propose an x-ray all-sky monitor for the International Space Station (ISS) that will be ten times more sensitive than past monitors and that opens up a new band of the soft x-ray spectrum (0.1 - 3.0 keV) for study. Taking advantage of the power telemetry and space available on the ISS we can use a telescope geometry and detectors that will provide better than 4 are minute resolution of the entire sky in a 1.5 hr duty cycle. To achieve this sensitivity and resolution we use focusing optics based on the lobster-eye geometry. We propose two approaches to the construction of the optics. The first method, well within the reach of existing technology, is to approximate the lobster-eye geometry by building crossed arrays of planar reflectors, this gives great control over the reflecting surface but is limited in terms of resolution at the baseline 4 are minute level. The second method is to use microchannel plates: this technology has the potential to greatly exceed the baseline resolution and sensitivity but is yet to be fully demonstrated. A simultaneous development of both approaches with selection of the superior candidate at the end of the development phase is suggested. The instrument is made of a number of modules based on a 2x2 cooled CCD detector array that covers an area of 6 x 6 cm(2) at the focal plane. Using optics with a radius of curvature of 0.75 m this gives each module a field of view of 9 degrees x 9 degrees. The modular approach gives us enormous flexibility in terms of physical arrangement on the ISS so that we may take advantage of clear lines of sight and also in terms of built-in redundancy. We estimate that similar to 50 such modules give us instantaneous coverage of 1/10 of the sky. The scientific case for this mission is almost too broad to state here. The instrument we describe will allow investigation of the long term light curves of thousands of AGN, it will detect thousands of transients, including GRBs and type II supernova, and the stellar coronae of hundreds of the brightest x-ray stars can be monitored. In addition the classical objectives of all-sky monitors - long-term all-sky archive and watchdog alert to new events - will be fulfilled at an unprecedented level. We also note that by opening up a little-explored band of the x-ray sky the opportunity for new discovery is presented. A satisfying example of entering new territory white still retaining the guarantee of expanding the domain of existing research. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Peele, AG (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 12 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 170 EP 175 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200027 ER PT S AU Hilsenrath, E Bhartia, PK Waldberg, G AF Hilsenrath, E Bhartia, PK Waldberg, G BE ElGenk, MS TI Observations of atmospheric pollution, aerosol, and chemistry from Space Station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID OZONE; SPECTROMETER AB Space observations are needed to study air quality on urban, regional, and super regional scales. Of particular importance is the ability to differentiate air pollution from natural and anthropogenic sources. Observations are needed for key air pollutant constituents in the troposphere such as ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and aerosols. An instrument suite has been designed that is capable of making these observations at urban scales on a global basis. The Space Station provides a practical platform to make these observations with the following capabilities: 51 degree inclination covers nearly all of the world's industrial regions; changing local observing time allows study of diurnal variation of chemically active atmospheric constituents; and serviceability which will afford an opportunity for precise instrument calibration updates needed for detecting long term changes in air quality. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hilsenrath, E (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 194 EP 199 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200031 ER PT S AU Rinsland, CP Chu, WP Cunnold, DM AF Rinsland, CP Chu, WP Cunnold, DM BE ElGenk, MS TI Solar occultation observations from the International Space Station: Deployment of a FTS for atmospheric chemistry and trend studies SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID STRATOSPHERIC AEROSOL; CHLORINE AB We propose the deployment of SAGE IV on the International Space Station (ISS) for recording solar occultation observations in the 2008-2013 time period. The design of SAGE IV is based on the SAGE III near UV-visible grating spectrometer with a 1.55 mu m PIN diode, but also includes a compact Fourier transform spectrometer operating between 740 and 4100 cm(-1). The combined instrumentation would focus on obtaining simultaneous high vertical resolution stratospheric profiles of ozone, over 30 other molecules, temperature, density, and aerosols at low to mid-latitudes to monitor the recovery of the ozone layer as the abundances of the chlorofluorocarbons decline. SAGE IV would extend the SAGE III ISS observational record to 2008-2013 with a consistent set of observations and data processing methods. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 200 EP 204 PG 5 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200032 ER PT S AU Jones, WV AF Jones, WV BE ElGenk, MS TI Opportunities for NASA Office of Space Science Funding of ISS payloads SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB It is NASA Office of Space Science (OSS) policy that International Space Station (ISS) research opportunities will be competed against other platforms and opportunities, i.e., there is no plan to have a set aside for developing ISS payloads. However, future Explorer Program solicitations will allow ISS investigations to compete on an equal basis with other missions requiring expendable launch vehicles, secondary-payload launches, etc. Commitment of Explorer Program resources, on the other hand, requires a three-year limit for instrument development. This means that ISS investigations will not be solicited by OSS until there is confidence that selected instruments can be launched within three years. Now that the ISS assembly is about to begin, the space science community should feel challenged to design instruments that can be built within the cost caps of the specific Explorer Program categories. C1 NASA, Off Space Sci, Code SR, Washington, DC 20546 USA. RP Jones, WV (reprint author), NASA, Off Space Sci, Code SR, Washington, DC 20546 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 284 EP 289 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200046 ER PT S AU Spinhirne, JD AF Spinhirne, JD BE ElGenk, MS TI Cloud and radiation mission with active and passive sensing from the Space Station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB A cloud and aerosol radiative forcing and physical process study involving active laser and radar profiling with a combination of passive radiometric sounders and imagers would use the space station as an observation platform. The objectives are to observe the full three dimensional cloud and aerosol structure and the associated physical parameters leading to a complete measurement of radiation forcing processes. The instruments would include specialized radar and lidar for cloud and aerosol profiling, visible; infrared and microwave imaging radiometers with comprehensive channels for cloud and aerosol observation and specialized sounders. The low altitude, available power and servicing capability of the space station are significant advantages for the active sensors and multiple passive instruments. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Spinhirne, JD (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 311 EP 314 PG 4 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200051 ER PT S AU Tsou, P AF Tsou, P BE ElGenk, MS TI Cosmic Dust Intact Capture Experiment SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The Cosmic Dust Intact Capture Experiment is based upon Exo-ICE, chosen as a Space Station Freedom Attached Payload. We have Incorporated the most recent inventions in aerogel along with simplified acoustic impact-detection system developed for STARDUST resulting in considerably improved and simplified experiment for the International Space Station. This experiment captures interplanetary and possibly interstellar cosmic dust Intact materials to Earth-based laboratories for detailed analysis and will expand the existing scientific research domain in the origin and history of planetary materials and biogenic elements and compounds. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsou, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 334 EP 340 PG 7 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200054 ER PT S AU Edelstein, W Kim, YJ Freeman, A Jordan, R AF Edelstein, W Kim, YJ Freeman, A Jordan, R BE ElGenk, MS TI Next generation SAR demonstration on Space Station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID IMAGING RADARS; FOREST BIOMASS AB This paper describes the next generation synthetic aperture radar (SAR) that enables future low cost space-borne radar missions. In order to realize these missions, we propose to use an inflatable, membrane, microstrip antenna that is particularly suitable for low frequency science radar missions. In order to mitigate risks associated with this revolutionary technology, the space station demonstration will be very useful to test the long-term survivability of the proposed antenna. This experiment will demonstrate several critical technology challenges associated with space-inflatable technologies. Among these include space-rigidization of inflatable structures, controlled inflation deployment, flatness and uniform separation of thin-film membranes and RF performance of membrane microstrip antennas. This mission will also verify the in-space performance of lightweight, high performance advanced SAR electronics. Characteristics of this SAR instrument include a capability for high resolution polarimetric imaging. The mission will acquire high quality scientific data using this advanced SAR to demonstrate the utility of these advanced technologies. We will present an inflatable L-band SAR concept for commercial and science applications and a P-band design concept to validate the Biomass SAR mission concept. The ionospheric effects on P-band SAR images will also be examined using the acquired data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Edelstein, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 352 EP 357 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200057 ER PT S AU Dalton, BP Jahns, GC Berthold, RW AF Dalton, BP Jahns, GC Berthold, RW BE ElGenk, MS TI New approaches to Space Station science operations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB This paper briefly describes processes, which have been utilized in initiating, developing, and facilitating Life Sciences experiments for Shuttle flights. The text will relate "changed" processes currently initiated and proposed processes, particularly for pre-flight biospecimen integration and flight controls. The experiment definition processes which have been implemented along with the anticipated results are discussed. A brief description is provided of the types and level of support provided to investigators during Spacelabs and the anticipated changes for the International Space Station. New proposed ground studies and the resultant data available to flight experiment proposers is related. The rationale for such changes is reviewed along with the beneficial assessment. C1 NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Dalton, BP (reprint author), NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 364 EP 369 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200059 ER PT S AU Antol, J Headley, DE AF Antol, J Headley, DE BE ElGenk, MS TI The International Space Station as a free flyer servicing node SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station will provide a multitude of opportunities for an expanding customer base to make use of this international resource. One such opportunity is servicing of various visiting vehicles that are in a similar orbit to the station. Servicing may include change-out; of payloads, replenishment of consumables, repair, and refurbishment operations. Previous studies have been conducted in which "paper" free flyers have been assessed against the station's ability to accommodate them. Over the last several months though: an already flown free flyer, EURECA. was assessed as a real-life visiting free flyer design reference mission. Issues such as capture/berthing, servicing, logistics support, and stowage were assessed for station design and operational approaches. This paper will highlight critical visiting vehicle design considerations, identify station issues, and provide recommendations for accommodation of a wide range of visiting vehicle requirements of the future. C1 NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Space Syst & Concepts Div, Hampton, VA 23681 USA. RP Antol, J (reprint author), NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Space Syst & Concepts Div, Mail Stop 328, Hampton, VA 23681 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 389 EP 393 PG 5 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200064 ER PT S AU Shields, CE AF Shields, CE BE ElGenk, MS TI The International Space Station: An opportunity for industry-sponsored global education SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station provides an excellent opportunity for industry sponsorship of international space education. As a highly visible worldwide asset, the space station already commands our interest. It has captured the imagination of the world's researchers and connected the world's governments. Once operational, it can also be used to capture the dreams of the word's children and connect the world's industry through education. The space station's global heritage and ownership; its complex engineering, construction, and operation: its flexible research and technology demonstration capability; and its long duration make it the perfect educational platform. These things also make a space station education program attractive to industry. Such a program will give private industry the opportunity to sponsor space-related activities even though a particular industry may not have a research or technology-driven need for space utilization. Sponsors will benefit through public relations and goodwill, educational promotions and advertising, and the sale and marketing of related products. There is money to be made by supporting, fostering, and enabling education in space through the International Space Station. This paper will explore various ISS education program and sponsorship options and benefits, will examine early industry response to such an opportunity, and will make the case for moving forward with an ISS education program as a private sector initiative. C1 NASA, Titusville, FL 32780 USA. RP Shields, CE (reprint author), NASA, 100 Boeing Way, Titusville, FL 32780 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 394 EP 396 PG 3 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200065 ER PT S AU Sandusky, J Jeganathan, M Ortiz, G Biswas, A Lee, S Wilson, K Parker, G Lesh, J AF Sandusky, J Jeganathan, M Ortiz, G Biswas, A Lee, S Wilson, K Parker, G Lesh, J BE ElGenk, MS TI Optical Communication Demonstration and High-Rate Link Facility SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Motivated by demands for faster, better, cheaper spacecraft, NASA is developing deep-space optical communication technology which promises reduced mass, volume, and power consumption compared to radiofrequency technology. While earth-orbiting optical receivers may eventually be employed, initial deep-space optical communication links are expected to utilize terrestrial telescope receivers. As the communication beam passes through the atmosphere, atmospheric turbulence causes the beam to scintillate, dramatically impacting its temporal and transverse nature. The statistics of these effects must be measured extensively if optical deep-space communication links are to be fully modeled and the design of deep-space communication links optimized. Sponsored by the Engineering Research and Technology Development program, the purposes of the Optical Communication Demonstration and High-Rate Link Facility are to demonstrate a Gbps-class optical downlink, gather extensive link statistics, and provide high-rate downlink capability. The Optical Communication Demonstration and High-Rate Link Facility will be deployed to the International Space Station by flight UF-4, currently scheduled for May 2002. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91109 USA. RP Sandusky, J (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 432 EP 437 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200073 ER PT S AU Landis, GA Sexton, A AF Landis, GA Sexton, A BE ElGenk, MS TI An engineering research Testbed for Photovoltaics SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The Ohio Aerospace Institute and the NASA Lewis Research Center are designing and building a solar-cell calibration facility, the Photovoltaic Engineering Testbed (PET) to fly on the International Space Station to calibrate, measure, and qualify advanced solar cell types in the space environment. PET will serve three primary functions: calibration, measurement, and qualification of solar cells, in order to bring new solar cell technologies to spaceflight readiness. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 438 EP 441 PG 4 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200074 ER PT S AU Cobb, SD Szofran, FR Schaefer, DA AF Cobb, SD Szofran, FR Schaefer, DA BE ElGenk, MS TI Preliminary concepts for the Materials Science Research Facility on the International Space Station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The Materials Science Research Facility (MSRF) is designed to accommodate the current and evolving cadre of peer-reviewed materials science investigations selected to conduct research in the microgravity environment of the International Space Station (ISS). The MSRF consists of modular autonomous Materials Science Research Racks (MSRRs). The initial MSRF concept consists of three Materials Science Research Racks (MSRR-1, MSRR-2, and MSRR-3) which will be developed for a phased deployment beginning on Utilization Flight 3. Each MSRR is a stand-alone autonomous rack and will be comprised of either on-orbit replaceable Experiment Modules, investigation unique apparatus, or multi-user generic processing apparatus. Each MSRR will support a wide variety of scientific investigations. C1 NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Div, Huntsville, AL 35812 USA. RP Cobb, SD (reprint author), NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Div, Huntsville, AL 35812 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 459 EP 464 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200077 ER PT S AU Johnson, L Herrmann, M AF Johnson, L Herrmann, M BE ElGenk, MS TI International Space Station electrodynamic tether reboost SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The International Space Station (ISS) will require periodic reboost due to atmospheric aerodynamic drag. This is nominally achieved through the use of thruster firings by the attached Progress M spacecraft. Many Progress flights to the ISS are required annually. Electrodynamic tethers provide an attractive alternative in that they can provide periodic reboost or continuous drag cancellation using no consumables, propellant, nor conventional propulsion elements. The system could also serve as an emergency backup reboost system used only in the event resupply and reboost are delayed for some reason. The system also has direct application to spacecraft and upper stage propulsion. Electrodynamic tethers have been demonstrated in space previously with the plasma motor generator (PMG) experiment and the Tethered Satellite System Reflight (TSS-LR). The advanced electrodynamic tether proposed for ISS reboost has significant advantages over previous systems in that higher thrust is achievable with significantly shorter tethers and without the need for an active current collection device, hence making the system simpler and much less expensive. C1 NASA, George C Marshall Space Flight Ctr, Adv Syst & Technol Off, Huntsville, AL 35812 USA. RP Johnson, L (reprint author), NASA, George C Marshall Space Flight Ctr, Adv Syst & Technol Off, Huntsville, AL 35812 USA. NR 2 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 490 EP 495 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200082 ER PT S AU Stadler, JH Hostetler, CA Williams-Byrd, J Hovis, F Bradford, CM Schwiesow, R AF Stadler, JH Hostetler, CA Williams-Byrd, J Hovis, F Bradford, CM Schwiesow, R BE ElGenk, MS TI Space-based laser for a cloud and aerosol backscatter lidar SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB NASA Langley Research Center in conjunction with Ball Aerospace & Technologies Corp., are developing a small, lightweight, diode-pumped Nd:YAG laser to enable a spaceborne backscatter lidar to measure clouds and aerosols. The frequency-doubled laser has total output energy of 220 mJ at 27 Hz. The laser has been specifically designed for space applications and features conductive cooling and a minimum three-year design life. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Stadler, JH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 602 EP 603 PG 2 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200094 ER PT S AU Krainak, M Abshire, J Cornwell, D Dragic, P Duerksen, G Switzer, G AF Krainak, M Abshire, J Cornwell, D Dragic, P Duerksen, G Switzer, G BE ElGenk, MS TI Research and development of laser diode based instruments for applications in space SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID BRAGG-REFLECTOR LASERS; PERFORMANCE; LIDAR AB Laser diode technology continues to advance at a very rapid rate due to commercial applications such as telecommunications and data storage. The advantages of laser diodes include, wide diversity of wavelengths, high efficiency, small size and weight and high reliability. Semiconductor and fiber optical-amplifiers permit efficient, high power master oscillator power amplifier (MOPA) transmitter systems. Laser diode systems which incorporate monolithic or discrete (fiber optic) gratings permit single frequency operation. We describe experimental and theoretical results of laser diode based instruments currently under development at NASA Goddard Space Flight Center including miniature lidars for measuring clouds and aerosols, water vapor and wind for Earth and planetary (Mars Lander) use. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krainak, M (reprint author), NASA, Goddard Space Flight Ctr, MC 554, Greenbelt, MD 20771 USA. RI Abshire, James/I-2800-2013 NR 12 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 604 EP 609 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200095 ER PT S AU Juhasz, AJ Tew, RC Schwarze, GE AF Juhasz, AJ Tew, RC Schwarze, GE BE ElGenk, MS TI Impact of radiation hardness and operating temperatures of silicon carbide electronics on space power system mass SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e), 1 MWe, and 10 MWe) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Juhasz, AJ (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,Mail Stop 301-3, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 610 EP 615 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200096 ER PT S AU Scheiman, DA Landis, GA Weizer, VG AF Scheiman, DA Landis, GA Weizer, VG BE ElGenk, MS TI High-bandgap solar cells for near-Sun missions SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB High bandgap solar cells are to be preferred for near-Sun, high operating-temperature environments, such as will be encountered by a Mercury orbiter or the Solar Probe mission. A GaInP solar cell is well suited for elevated temperature performance because it is available and has a bandgap high enough to produce reasonable performance at temperatures above 400 degrees C. The cell is currently commercially available as the top cell of a multi-junction solar cell. temperatures above 400 degrees C. The cell is currently commercially available as the top cell or a multi-junction A cell contact metallization needs to be developed that can operate without degradation at high temperature. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Scheiman, DA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 10 TC 5 Z9 5 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 616 EP 620 PG 5 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200097 ER PT S AU Jaworske, DA Skowronski, TJ Miles, BJ AF Jaworske, DA Skowronski, TJ Miles, BJ BE ElGenk, MS TI Optical evaluation of an As-manufactured compound secondary concentrator SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Secondary concentrators are needed in solar thermal propulsion to further concentrate the energy collected by large lightweight primary concentrators. Although the physics of secondary concentrators has been worked out in detail and the manufacturing has been successfully completed for a ground demonstration, there is a need to quantify the specific performance of as-manufactured concentrators. This paper summarizes the properties of a secondary concentrator manufactured for the Integrated Solar Upper Stage engine ground demonstration in 1997 and presents data obtained from the optic that describe the performance of the as-manufactured component. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Jaworske, DA (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 621 EP 626 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200098 ER PT S AU de Groh, KK Smith, DC Wheeler, DR MacLachlan, BJ AF de Groh, KK Smith, DC Wheeler, DR MacLachlan, BJ BE ElGenk, MS TI Effects of ambient high temperature exposure on alumina-titania high emittance surfaces for solar dynamic systems SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Solar dynamic (SD) space power systems require durable, high emittance surfaces on a number of critical components, such as hear receiver interior surfaces and parasitic load radiator (PLR) elements. To enhance surface characteristics, an alumina-titania coating has been applied to 500 heat receiver thermal energy containment canisters and the PLR of NASA Lewis Research Center's (LeRC) 2 kW SD ground test demonstrator(GTD). The alumina-titania coating was chosen because it had been found to maintain its high emittance under vacuum (less than or equal to 10(-6) torr) at high temperatures (1457 degrees F (827 degrees C)) for an extended period (approximate to 2,700 hours). However, preflight verification of SD systems components, such as the PLR, require operation at ambient pressure and high temperatures. Therefore, the purpose of this research was to evaluate the durability of the alumina-titania coating at high temperature in air. Fifteen of sixteen alumina-titania coated Incoloy samples were exposed to high temperatures (600 degrees F (316 degrees C) to 1500 degrees F (816 degrees C)) for various durations (2 to 32 hours). Samples were characterized prior to, and after, heat treatment for reflectance, solar absorptance, room temperature emittance and emittance at 1200 degrees F (649 degrees C). Samples were also examined to detect physical defects and to determine surface chemistry using optical microscopy, scanning electron microscopy, operated with an energy dispersive spectroscopy (EDS) system, and x-ray photoelectron spectroscopy (XPS). Visual examination of the heat-treated samples showed a whitening of samples exposed to temperatures of 1000 degrees F (538 degrees C) and above. Correspondingly, the optical properties of these samples had degraded. A sample exposed to 1500 degrees F (816 degrees C) for 24 hours had whitened and the thermal emittance at 1200 degrees F (649 degrees C) had decreased from the non-heat treated value of 0.94 to 0.62. The coating on this sample had become embrittled, with spalling off the substrate noticeable at several locations. Based on this research it is recommended that preflight testing of SD components with alumina-titania coatings be restricted to temperatures no greater than 600 degrees F (316 degrees C) in air to avoid optical degradation. Moreover, components with the aluminia-titania coating are likely to experience optical property degradation with direct atomic oxygen exposure in space. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP de Groh, KK (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 0 Z9 0 U1 2 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 627 EP 635 PG 9 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200099 ER PT S AU Rabideau, G Chien, S Backes, P Chalfant, G Tso, K AF Rabideau, G Chien, S Backes, P Chalfant, G Tso, K BE ElGenk, MS TI A step towards an autonomous planetary rover SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP Conference Proceedings LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Recently, significant advances have been made in enabling autonomous revers and robotic vehicles. Current robotic vehicles employ significant elements of autonomy in their low-level operations and control. A further important step is the integration of high-level intelligent systems with autonomous rover control architectures. in this paper, we describe the integration of two software systems: ASPEN (Automated Scheduling and Planning Environment) and WITS (Web Interface for TeleScience). WITS provides a high-level graphical interface to Rocky7, an experimental rover developed by the Jet Propulsion Laboratory (JPL). Using WITS, a user can naturally specify science activities and locations using actual images of the rover's environment. ASPEN accepts the science goals input using WITS, reasons about the low-level activities and resources required to achieve these goals, and generates the executable sequence to enable achievement of the requested goals. Future steps would include a migration of this software to the rover itself, allowing the rover to schedule its own activities, and thus behave more autonomously. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 648 EP 653 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200102 ER PT S AU Dvorak, D Tailor, E AF Dvorak, D Tailor, E BE ElGenk, MS TI Verification of autonomous systems using embedded behavior auditors SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The prospect of highly autonomous spacecraft and revers is exciting for what they can do with onboard decision making, but also troubling for what they might do [improperly] without human-in-the-loop oversight. The single biggest obstacle to acceptance of highly autonomous software control systems is doubt about their trustworthiness as a replacement for human analysis and decision-making. Such doubts can be addressed with a comprehensive system verification effort, but techniques suitable for conventional sequencer-based systems are inadequate for reactive systems. This paper highlights some of the key features that distinguish autonomous systems from their predecessors and then focuses on one approach to aid in their verification using a "lightweight": formal method. Specifically, we present a little language that enables system engineers acid designers to specify expected behavior in the form of invariants: state machines, episodes, and resource constraints, and a way of compiling such specifications and linking them into the operational code as embedded behavior auditors. Such auditors become part of the overall Fault-detection design, checking system behavior in real-time, not only in the test-bed but also in flight. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dvorak, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 301-270, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 654 EP 659 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200103 ER PT S AU Gat, E AF Gat, E BE ElGenk, MS TI Non-linear sequencing and cognizant failure SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB dSpacecraft are traditionally commanded using linear sequences of time-based commands. Linear sequences work fairly well, but they are difficult and expensive to generate, and are usually not capable of responding to contingencies. Any anomalous behavior while executing a linear sequence generally results in the spacecraft entering a safe mode. Critical sequences like orbit insertions which must be able to respond to faults without going into safe mode are particularly difficult to design and verify. The effort needed to generate command sequences can be reduced by extending the vocabulary of sequences to include more sophisticated control constructs. The simplest extensions are conditionals and loops. Adding these constructs would make a sequencing language look more or less like a traditional programming language or scripting language, and would come with all the difficulties associated with such a language. In particular, verifying the correctness of a sequence would be tantamount to verifying the correctness of a program, which is undecidable in general. We describe an extended vocabulary for non-linear sequencing based on the architectural notion of cognizant failure. A cognizant failure architecture is divided into components whose contract is to either achieve (or maintain) a certain condition, or report that they have failed to do so. Cognizant failure is an easier condition to verify than correctness, but it can provide high confidence in the safety of the spacecraft. Because cognizant failure inherently implies some kind of representation of the intent of an action, the system can respond to contingencies in more robust and general ways. We will describe an implemented nonlinear sequencing system that is being flown on the NASA New Millennium Deep Space 1 Mission as part of the Remote Agent Experiment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gat, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 660 EP 666 PG 7 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200104 ER PT S AU Alkalai, L Kolawa, E AF Alkalai, L Kolawa, E BE ElGenk, MS TI Avionics systems on a chip for space exploration SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The advanced miniaturization of all the on-board spacecraft functions into a highly integrated, modular, and reliable architecture is a major enabling technology for future deep-space and Earth orbiting science missions. Avionics miniaturization using advanced deep sub-micron semiconductor digital, analog, as well as Micro Electro Mechanical Systems (MEMS) technologies will revolutionize the way we build future spacecraft systems. So called micro and nano satellites as well as other micro-systems are possible using these advanced technologies. In this paper, we present an overview of work in progress at the newly established JPL Center for Integrated Space Microsystems (CISM) in the area of Avionics Systems On a Chip Program. This long-term research and development program has been established as part of NASA's Advanced Deep Space Systems Program (a.k.a. X2000), which also has a near-term project-oriented element, as well as an even longer term research component called Revolutionary Computing Technologies. This paper will outline the vision, goals and scope of the SOAC program, as well as its target mission insertion opportunities. We also describe a technology roadmap from 1998 to 2006 leading to Systems On A Chip technology elements. Also described are the SOAC technology challenges and research components. The first SOAC prototype has been designed and submitted for fabrication at the MIT/LL 0.25 micron Silicon On Insulator (SOI) foundry in July 1998. It contains a telecommunications unit, power management unit, on-chip computer, non-volatile as well as volatile storage, all on a single chip. The chip will be tested at JPL in the second quarter of 1999. C1 CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, Pasadena, CA 91109 USA. RP Alkalai, L (reprint author), CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, 4800 Oak Grove Dr,MS 303-310, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 721 EP 728 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200114 ER PT S AU Butler, D AF Butler, D BE ElGenk, MS TI Overview of CPL and LHP applications on NASA missions SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Capillary Pumped Loops (CPL's) and Loop Heat Pipes (LHP's) are finding increased acceptance on upcoming NASA spacecraft missions, as well as military and commercial applications. The transition from a research and development tool to an "off the shelf" system is underway. The state of the art of two phase systems (TPS) is reviewed and applications on various NASA missions are discussed, with particular emphasis on new technology developments. Upcoming research areas and flight experiments are also addressed, along with recommendations for future activities. C1 NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Greenbelt, MD 20771 USA. RP Butler, D (reprint author), NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Code 545, Greenbelt, MD 20771 USA. NR 9 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 792 EP 798 PG 7 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200124 ER PT S AU Kaya, T Ku, JT Hoang, TT Cheung, MK AF Kaya, T Ku, JT Hoang, TT Cheung, MK BE ElGenk, MS TI Investigation of low power start-up characteristics of a loop heat pipe SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB An important problem of the all two-phase thermal transport devices is their start-up characteristics. Although Loop Heat Pipes (LHPs) are easier to start than Capillary Pumped Loops (CPLs), both devices may experience start-up problems at low powers. In this study, the low power start-up characteristics of an LHP were experimentally investigated at different loop orientations. The start-up parameters such as the superheat and the time required for evaporation were analyzed. The minimum start-up power was searched at the horizontal and vertical positions of the loop. In explaining the observed phenomena: the importance of the heat leak, and the presence of the vapor bubbles in the vapor grooves prior to start-up was emphasized. C1 NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Greenbelt, MD 20771 USA. RP Kaya, T (reprint author), NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Greenbelt, MD 20771 USA. RI Kaya, Tarik/C-1215-2008 NR 4 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 799 EP 804 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200125 ER PT S AU Allen, JS Hallinan, KP AF Allen, JS Hallinan, KP BE ElGenk, MS TI A study of the fundamental operation of a capillary-driven heat transfer device in both normal and low gravity part 2. Effect of evaporator meniscus oscillations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Research has been conducted to observe the operation of a capillary-pumped loop (CPL) in both normal and low-gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped loops in low gravity are not understood and the available data for analyzing the failures has been scarce. To observe failure in these devices, an idealized experimental CPL was configured for testing. The experimental test loop was constructed of Pyrex tubing to allow for visualization of system operations. Heat was added to the liquid on the evaporator side of the loop using resistance heaters and removed on the condenser side via forced convection of ambient air. A video camera was used to record the behavior of both the condenser and the evaporator menisci simultaneously. Low-gravity experiments were performed during the Microgravity Science Laboratory mission onboard the Space Shuttle Columbia in July of 1997. From this experiment, wall temperature and vapor pressure fluctuations have been correlated directly to oscillations of the evaporating meniscus. This correlation provides evidence that the oscillatory behavior of the evaporating meniscus contributes to evaporator dry out which is the primary cause of failure in capillary-pumped loops in low gravity. C1 NASA, Lewis Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Allen, JS (reprint author), NASA, Lewis Res Ctr, Natl Ctr Micrograv Res, MS 1100-3,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 28 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 811 EP 817 PG 7 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200127 ER PT S AU Holt, AC AF Holt, AC BE ElGenk, MS TI International space station advanced propulsion technology R&D SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The international Space Station (ISS) is a cost-effective technology testbed which can be used to support research and development (R.&D.) activities and demonstration tests for advanced space technology systems. These advanced systems are needed for Space Station Pre-Planned Program Improvements ((PI)-I-3), near-Earth commercialization activities and human exploration missions. The ISS, advanced space technology R.&D. and testing capabilities include the capability to develop and test advanced propulsion/transport systems, both on (attached to) the International Space Station (ISS) and on future ISS based or visiting platforms (most likely commercially provided). Feasibility assessments of proposed, advanced propulsion research and development (R.&D.) and demonstration tests, will likely include new types of guidance, navigation and control (GN&C) operations and associated safety considerations. A GN&C software model of a specific advanced propulsion concept is used to examine some of these considerations. Some challenges, but no major barriers are identified to using the International Space Station (ISS) (and future ISS based or serviced platforms) to conduct R.&D. and demonstration testing of very advanced or breakthrough propulsion systems relying on highly non-linear field and particle effects. The international Space Station's R.&D. and testing capability is needed to develop the technologies and systems required to cost-effectively implement human exploration, and outpost missions to Mars. The R. &D. and testing conducted on the International Space Station will pave the way for the more demanding R.&D. and testing needed to develop and space qualify the technology which will take us to the moons of the outer planets, and eventually to Earth-like planets in nearby star systems. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Holt, AC (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code OZ4, Houston, TX 77058 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1021 EP 1026 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200159 ER PT S AU Rivers, HK AF Rivers, HK BE ElGenk, MS TI Conformal cryogenic tank trade study for reusable launch vehicles SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Future reusable launch vehicles may be lifting bodies with non-circular cross section like the proposed Lockheed-Martin VentureStar(TM). Current designs for the cryogenic tanks of these vehicles are dual-lobed and quad-lobed tanks which are packaged more efficiently than circular tanks, but still have low packaging efficiencies with large gaps existing between the vehicle outer mold line and the outer surfaces of the tanks. In this study, tanks that conform to the outer mold line of a non-circular vehicle were investigated. Four structural concepts for conformal cryogenic tanks and a quad-lobed tank concept were optimized for minimum weight designs. The conformal tank concepts included a sandwich tank stiffened with axial tension webs, a sandwich tank stiffened with transverse tension webs, a sandwich tank stiffened with rings and tension ties, and a sandwich tank stiffened with orthogrid stiffeners and tension ties. For each concept, geometric parameters (such as ring frame spacing, the number and spacing of tension ties or webs, and tank corner radius) and internal pressure loads were varied and the structure was optimized using a finite-element-based optimization procedure. Theoretical volumetric weights were calculated by dividing the weight of the barrel section of the tank concept and its associated frames, webs and tension ties by the volume it circumscribes. This paper describes the four conformal tank concepts and the design assumptions utilized in their optimization. The conformal tank optimization results included theoretical weights, trends and comparisons between the concepts, are also presented, along with results from the optimization of a quad-lobed tank. Also, the effects of minimum gauge values and non-optimum weights on the weight of the optimized structure are described in this paper. C1 NASA, Langley Res Ctr, Thermal Struct Branch, Div Struct, Hampton, VA 23681 USA. RP Rivers, HK (reprint author), NASA, Langley Res Ctr, Thermal Struct Branch, Div Struct, MS-396, Hampton, VA 23681 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1075 EP 1086 PG 12 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200166 ER PT S AU Sawyer, JW Hodge, J Moore, B Snyder, K AF Sawyer, JW Hodge, J Moore, B Snyder, K BE ElGenk, MS TI Aerothermal test of Thermal Protection Systems for X-33 reusable launch vehicle SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB An array of metallic Thermal Protection System (TPS) panels developed for the windward surface of the: X-33 vehicle was tested in the 8-Foot High Temperature Tunnel at the NASA Langley Research Center. These tests were the first aerothermal tests of an X-33 TPS array and the test results will be used to validate the TPS for the X-33 flight program. Specifically, the tests evaluated the structural and thermal performance of the TPS, the effectiveness of the high temperature seals between adjacent panels and the durability of the TPS under realistic aerothermal flight conditions. The effect of varying panel-to-panel step heights, intentional damage to the seals between adjacent panels, and the use of secondary seals were also investigated during the test program. The metallic TPS developed for the windward surface of the X-33, the blanket TPS developed to protect the leeward surfaces of the X-33, and the test program in the 8-Foot High Temperature Tunnel are presented and discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Sawyer, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 8 TC 0 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1087 EP 1100 PG 14 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200167 ER PT S AU Dorsey, JT Wu, C Rivers, K Martin, C Smith, R AF Dorsey, JT Wu, C Rivers, K Martin, C Smith, R BE ElGenk, MS TI Airframe integration trade studies for a Reusable Launch Vehicle SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Future launch vehicles must be lightweight, fully reusable and easily maintained if low-cost access to space is to be achieved. The goal of achieving an economically viable Single-Stage-to-Orbit (SSTO) Reusable Launch Vehicle (RLV) is not easily achieved and success will depend to a large extent on having an integrated and optimized total system. A series of trade studies were performed to meet three objectives. First, to provide structural weights and parametric weight equations as inputs to configuration-level trade studies. Second, to identify, assess and quantify major weight drivers for the RLV airframe. Third, using information on major weight drivers, and considering the RLV as an integrated thermal structure (composed of thrust structures, tanks, thermal protection system, insulation and control surfaces), identify and assess new and innovative approaches or concepts that have the potential for either reducing airframe weight, improving operability, and/or reducing cost. C1 NASA, Langley Res Ctr, Thermal Struct Branch, Hampton, VA 23681 USA. RP Dorsey, JT (reprint author), NASA, Langley Res Ctr, Thermal Struct Branch, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1106 EP 1119 PG 14 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200169 ER PT S AU Campbell, JW Taylor, CR Smalley, LL Dickerson, T AF Campbell, JW Taylor, CR Smalley, LL Dickerson, T BE ElGenk, MS TI Laser/space material uncooperative propulsion for orbital debris removal and asteroid, meteoroid, and comet deflection SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Orbital debris in low-Earth orbit in the size range from 1 to 10 cm in diameter can be detected but not tracked reliably enough to be avoided by spacecraft. It can cause catastrophic damage even to a shielded spacecraft. With adaptive optics, a ground-based pulsed laser ablating the debris surface can produce enough propulsion in several hundred pulses to cause such debris to reenter the atmosphere. A single laser station could remove all of the 1-10 cm debris in three years or less. A technology demonstration of laser space propulsion is proposed which would pave the way for the implementation of such a debris removal system. The cost of the proposed demonstration is comparable with the estimated annual cost of spacecraft operations in the present orbital debris environment. Orbital debris is not the only space junk that is deleterious to the Earth's environment. Collisions with asteroids have caused major havoc to the Earth's biosphere many times in the ancient past. Since the possibility still exists for major impacts, it shown that it is possible to scale up the systems to prevent these catastrophic collisions given sufficient early warning. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Campbell, JW (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Stop PS02, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 U1 2 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1237 EP 1246 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200189 ER PT S AU Borowski, SK Dudzinski, LA McGuire, ML AF Borowski, SK Dudzinski, LA McGuire, ML BE ElGenk, MS TI "Bimodal" NTR and LANTR propulsion for human missions to Mars/Phobos SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The nuclear thermal rocket (NTR) is one of the leading propulsion options for future human missions to Mars due to its high specific impulse (Isp similar to 850-1000 s) and attractive engine thrust-to-weight ratio (similar to 3-10). Because only a miniscule amount of enriched uranium-235 fuel is consumed in a NTR during the primary propulsion maneuvers of a typical Mars mission, engines configured for both propulsive thrust and modest power generation (referred to as "bimodal" operation) provide the basis for a robust, "power-rich" stage enabling propulsive Mars capture and reuse capability. A family of modular "bimodal" NTR (BNTR) vehicles are described which utilize a common "core" stage powered by three 66.7 kN (similar to 15 klbf) BNTRs that produce 50 kWe of total electrical power for crew life support, an active refrigeration / reliquification system for long term, "zero-boiloff" liquid hydrogen (LH2) storage, and high data rate communications. Compared to other propulsion options, a Mars mission architecture using BNTR transfer vehicles requires fewer transportation system elements which reduces mission mass, cost and risk because of simplified space operations. For difficult Mars options, such as a Phobos rendezvous and sample return mission, volume (not mass) constraints limit the performance of the "all LH2" BNTR stage. The use of "LOX-augmented" NTR (LANTR) engines, operating at a modest oxygen-to-hydrogen (O/H) mixture ratio (MR) of 0.5, helps to increase "bulk" propellant density and total thrust during the trans-Mars injection (TMI) burn. On all subsequent burns, the bimodal LANTR engines operate on LH2 only (MR = 0) to maximize vehicle performance while staying within the mass limits of two similar to 80 t "Magnum" heavy lift launch vehicles (HLLVs). C1 NASA, Lewis Res Ctr, Launch Serv, Cleveland, OH 44135 USA. RP Borowski, SK (reprint author), NASA, Lewis Res Ctr, Launch Serv, Cleveland, OH 44135 USA. NR 2 TC 3 Z9 3 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1261 EP 1268 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200192 ER PT S AU Gefert, LP Hack, KJ Kerslake, TW AF Gefert, LP Hack, KJ Kerslake, TW BE ElGenk, MS TI Options for the human exploration of Mars using solar electric propulsion SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Solar Electric propulsion (SEP) is examined as a candidate transportation option for human missions to Mars. Focus is given to an Earth-escape staging concept. This concept uses a SEP system to transfer from low earth orbit (LEO) to a high-energy elliptical parking orbit (HEEPO) and a chemical propulsion system to transfer from the HEEPO to a hyperbolic escape trajectory. LEO to Earth escape performance of these combined transportation systems is comparable to that of a nuclear thermal rocket (NTR). As a result, a mass efficient non-nuclear transportation architecture with fast, 180 day, Earth-to-Mars piloted transit times is enabled. C1 NASA, Lewis Res Ctr, Syst Engn Div, Cleveland, OH 44135 USA. RP Gefert, LP (reprint author), NASA, Lewis Res Ctr, Syst Engn Div, Bldg 500,Rm 2417,2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 8 Z9 8 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1275 EP 1280 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200194 ER PT S AU Ryan, MA Williams, RM Homer, ML Shields, VB Wright, S Lara, L Miller, J AF Ryan, MA Williams, RM Homer, ML Shields, VB Wright, S Lara, L Miller, J BE ElGenk, MS TI Performance parameters of TiN electrodes for AMTEC cells SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID INTERFACIAL IMPEDANCE; TRANSPORT; KINETICS; ALUMINA AB In order to model the lifetime of the electrochemical cell in an Alkali Metal Thermal to Electric Converter (AMTEC), studies of TiN electrodes on beta "-alumina solid electrolytes (BASE) have been made to determine the performance parameters over time. Performance parameters include, G, the morphology factor, and B, the temperature independent exchange current The results of several experiments, both AMTEC cells and Sodium Exposure Test Cells, in which TiN electrodes have been studied at 1120 - 1200 K are described here. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ryan, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1301 EP 1305 PG 5 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200198 ER PT S AU Williams, RM Ryan, MA Homer, ML Lara, L Manatt, K Shields, V Cortez, RH Kulleck, J AF Williams, RM Ryan, MA Homer, ML Lara, L Manatt, K Shields, V Cortez, RH Kulleck, J BE ElGenk, MS TI The thermal stability of sodium beta" - Alumina solid electrolyte ceramic in AMTEC cells SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc ID CONDUCTIVITY AB A critical component of alkali metal thermal-to electric converter (AMTEC) devices for long duration space missions is the beta "-alumina solid electrolyte ceramic (BASE), for which there exists no substitute. The temperature and environmental conditions under which BASE remains stable control operational parameters of AMTEC devices. We have used mass loss experiments in vacuum to 1573K to characterize the kinetics of BASE decomposition, and conductivity and exchange current measurements in sodium vapor filled exposure cells to 1223K to investigate changes in the BASE which affect its ionic conductivity. There is no clear evidence of direct thermal decomposition of BASE below 1273K, although limited soda loss may occur. Reactive metals such as Mn or Cr can react with BASE at temperatures at least as low as 1223K. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1306 EP 1311 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200199 ER PT S AU Williams, CH Borowski, SK Dudzinski, LA Juhasz, AJ AF Williams, CH Borowski, SK Dudzinski, LA Juhasz, AJ BE ElGenk, MS TI A spherical torus nuclear fusion reactor space propulsion vehicle concept for fast interplanetary travel SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB A conceptual vehicle design enabling fast outer solar system travel was produced predicated on a small aspect ratio spherical torus nuclear fusion reactor. Initial requirements were for a human mission to Saturn with a > 5% payload mass fraction and a one way trip time of less than one year. Analysis revealed that the vehicle could deliver a 108 mt crew habitat payload to Saturn rendezvous in 235 days, with an initial mass in low Earth orbit of 2,941 mt. Engineering conceptual design, analysis, and assessment was performed on all major systems including payload, central truss, nuclear reactor (including divertor and fuel injector), power conversion (including turbine, compressor, alternator, radiator, recuperator, and conditioning), magnetic nozzle, neutral beam injector, tankage, start/re-start reactor and battery, refrigeration, communications, reaction control, and in-space operations. Detailed assessment was done on reactor operations, including plasma characteristics, power balance, and component design. C1 NASA, Lewis Res Ctr, Launch serv, Cleveland, OH 44135 USA. RP Williams, CH (reprint author), NASA, Lewis Res Ctr, Launch serv, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1319 EP 1326 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200201 ER PT S AU Stabb, J AF Stabb, J BE ElGenk, MS TI Evolving the launch approval process SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB With many of us having participated in the rigors and reviews of the launch approval process, most feel that some aspects of the process could be streamlined. A more effective launch approval process would shorten and coordinate the deliverable schedules, reduce costs, and help the public understand the integrity of the overall launch approval process, This paper investigates the relationships between various deliverable analyses in order to determine if any improvements can be made. An evolved launch approval process will be presented and tested using a uranium core based power system. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Stabb, J (reprint author), NASA, Kennedy Space Ctr, FL 32899 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1345 EP 1350 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200205 ER PT S AU Caillat, T Fleurial, JP Snyder, CJ Zoltan, A Zoltan, D Borshchevsky, A AF Caillat, T Fleurial, JP Snyder, CJ Zoltan, A Zoltan, D Borshchevsky, A BE ElGenk, MS TI Progress in the development of high efficiency segmented thermoelectric generators SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The integration of new more efficient thermoelectric materials developed at the Jet Propulsion Laboratory into a new high performance segmented thermoelectric generator has been reported earlier. Progress in the development of this new segmented thermoelectric generator is reported in this paper. This generator would operate over a large temperature difference (300-973K) and uses novel segmented legs based on a combination of state-of-the-art thermoelectric materials and p-type Zn4-xCdxSb3 alloys, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys. An increase in the thermoelectric materials conversion efficiency of about 60% is expected compared to Bi2Te3- and PbTe-based generators. A computer program was written to optimize the thermal efficiency of the device. The optimal geometry, power output, efficiency and other properties of the generator were calculated and are presented. In addition results of bonding studies between Zn4Sb3 and Bi0.4Sb1.6Te3 are reported and discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Caillat, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011 OI Snyder, G. Jeffrey/0000-0003-1414-8682 NR 3 TC 9 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1403 EP 1407 PG 5 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200214 ER PT S AU Mason, LS AF Mason, LS BE ElGenk, MS TI Technology projections for solar dynamic power SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB Solar Dynamic power systems can offer many potential benefits to Earth orbiting satellites including high solar-to-electric efficiency, long life without performance degradation, and high power capability. A recent integrated system test of a 2 kilowatt SD power system in a simulated space environment has successfully demonstrated technology readiness for space flight. Conceptual design studies of SD power systems have addressed several potential mission applications: a 10 kilowatt LEO satellite, a low power Space Based Radar, and a 30 kilowatt GEO communications satellite. The studies show that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the conceptual design studies as a basis, a SD technology roadmap was generated which identifies the component advances necessary to assure SD systems a competitive advantage for future NASA, DOD, and commercial missions. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Mason, LS (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1420 EP 1425 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200217 ER PT S AU Shatens, RK Mason, LS AF Shatens, RK Mason, LS BE ElGenk, MS TI 800 hours of operational experience from a 2 kW(e) Solar Dynamic system SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB From December 1994 to September 1998, testing with a 2 kWe Solar Dynamic power system resulted in 33 individual tests, 886 hours of solar heating, and 783 hours of power generation. Power generation ranged from 400 watts to over 2 kW(e), acid SD system efficiencies have been measured up to 17 per cent, during simulated low-Earth orbit operation. Further, the turbo-alternator-compressors successfully completed 100 start/stops on foil bearings. Operation was conducted in a large thermal/vacuum facility with a simulated Sun at the NASA Lewis Research Center. The Solar Dynamic system featured a closed Brayton conversion unit integrated with a solar heat receiver, which included thermal energy storage for continuous power output through a typical low-Earth orbit. Two power conversion units and three alternator configurations were used during testing. This paper will review the test program, provide operational and performance data, and review a number of technology issues. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Shatens, RK (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1426 EP 1431 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200218 ER PT S AU Mason, LS AF Mason, LS BE ElGenk, MS TI Surface nuclear power for human Mars missions SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB The Design Reference Mission for NASA's human mission to Mars indicates the desire for in-situ propellant production and bio-regenerative life systems to ease Earth launch requirements. These operations, combined with crew habitation and science, result in surface power requirements approaching 160 kilowatts. The power system, delivered on an early cargo mission, must be deployed and operational prior to crew departure from Earth. The most mass efficient means of satisfying these requirements is through the use of nuclear power. Studies have been performed to identify a potential system concept using a mobile cart to transport the power system away from the Mars lander and provide adequate separation between the reactor and crew. The studies included an assessment of re-actor and power conversion technology options, selection of system and component redundancy, determination of optimum separation distance, and system performance sensitivity to some key operating parameters. The resulting system satisfies the key mission requirements including autonomous deployment, high reliability, and cost effectiveness at a overall system mass of 12 tonnes and a stowed volume of about 63 m(3). C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Mason, LS (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1464 EP 1469 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200224 ER PT S AU Curreri, PA Criswell, DR AF Curreri, PA Criswell, DR BE ElGenk, MS TI In situ production of solar power systems for exploration: Potential for in situ rectenna production on Mars SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1999, PTS ONE AND TWO SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1999 Space Technology and Applications International Forum (STAIF-99) - Opportunities and Challenges for the New Millennium CY JAN 31-FEB 04, 1999 CL ALBUQUERQUE, NM SP Boeing Co, Lockheed Martin Astronaut, NASA, USAF, Air Force Res Lab, US DOE, IAF 99, Amsterdam, Amer Inst Chem Engineers, AIAA, Amer Astronaut Soc, ASME Int, Amer Inst Aeronaut & Astronaut, Amer Inst Chem Engineers, Heat Transfer & Energ Convers Div, Amer Nucl Soc, Trin Sect, Amer Soc Mech Engineers, Nucl Engn Div & Heat Transfer Div, Inst Elect & Electr Engineers Inc, Nucl & Plasma Sci Soc, NASA Natl Space Grant Coll & Fellowship Program, New Mexico Space Grant Consortium, Profess Aerosp Contractors Assoc AB In situ derived expandable power is a key to eventual Mars base self-sufficiency. Initial studies for a non-nuclear human Mars reference mission rely on a large area of solar cells with energy storage for night power requirements. Preliminary studies indicate that utilization of Solar Electric Propulsion vehicles in Mars areosynchronous orbit might competitively provide continuous power if laser or 245 GHz microwave power transmission were utilized. This paper looks at the potential to reduce landed mass on Mars for a non-nuclear human mission and thus reduce mission cost by making the power receiving rectennas in situ on Mars surface. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Curreri, PA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-846-0 J9 AIP CONF PROC PY 1999 VL 458 BP 1623 EP 1628 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Multidisciplinary; Geosciences, Multidisciplinary; Multidisciplinary Sciences; Nuclear Science & Technology; Remote Sensing; Physics, Applied; Physics, Multidisciplinary SC Engineering; Thermodynamics; Geology; Science & Technology - Other Topics; Nuclear Science & Technology; Remote Sensing; Physics GA BM78K UT WOS:000079755200247 ER PT S AU Munk, MM AF Munk, MM BE Bishop, RH Mackison, DL Culp, RD Evans, MJ TI Departure energies, trip times and entry speeds for human Mars missions SO SPACEFLIGHT MECHANICS 1999, VOL 102, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th Annual Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The study examines how the mission design variables departure energy, entry speed, and trip time vary for round-trip conjunction-class Mars missions. These three parameters must be balanced in order to produce a mission that is acceptable in terms of mass, cost, and risk. For the analysis, a simple, massless-planet trajectory program was employed. The premise of this work is that if the trans-Mars and trans-Earth injection stages are designed for the most stringent opportunity in the energy cycle, then there is extra energy capability in the "easier" opportunities which can be used to decrease the planetary entry speed, or shorten the trip time. Both of these effects are desirable for a human exploration program. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Munk, MM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-458-3 J9 ADV ASTRONAUT SCI PY 1999 VL 102 BP 39 EP 50 PN 1&2 PG 12 WC Engineering, Aerospace SC Engineering GA BN45R UT WOS:000081956900004 ER PT S AU Haines, BJ Lichten, SM Lough, MF Muellerschoen, RJ Vigue-Rodi, Y AF Haines, BJ Lichten, SM Lough, MF Muellerschoen, RJ Vigue-Rodi, Y BE Bishop, RH Mackison, DL Culp, RD Evans, MJ TI Determining precise orbits for TOPEX/POSEIDON within one day of real time: Results and implications SO SPACEFLIGHT MECHANICS 1999, VOL 102, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th Annual Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID TOPEX POSEIDON AB Radar altimeter missions require precise estimates of the satellite radial orbit position in order to support measurement of surface heights. Traditional applications of altimeter data have not placed serious demands on the timeliness of this precise orbit information. Many of these applications involve retrospective scientific analysis of phenomena such as ocean current patterns, permanent geoid features, and slow changes in the thickness of the polar ice sheets. For these studies, latencies of days to weeks in receiving the precise altimeter data sets provide little impediment to successfully completing the research. Owing to the continuing successes of the Topex/Poseidon (T/P) and ERS missions, however, we are presently witness to the beginnings of a new operational era in satellite altimetry. The most demanding of the operational applications, e.g., short-term climate forecasting, require that accurate orbits be made available in near-real time. Precise orbit determination techniques based on data from on-board global positioning system (GPS) receivers have contributed significantly to meeting these requirements and show great promise for keeping pace with the demands of future missions. In this paper, we describe recent advances in near-real-time orbit determination for the T/P mission. New results suggest that GPS-based orbits computed within one day of recording the last element of tracking data have radial accuracies of about 3 cm in a root-mean-square (RMS) sense. These orbits are used by a variety of specialized users in the oceanographic community in order to support climate forecasting and realtime monitoring of the global ocean. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Haines, BJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 3 Z9 3 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-458-3 J9 ADV ASTRONAUT SCI PY 1999 VL 102 BP 623 EP 634 PN 1&2 PG 12 WC Engineering, Aerospace SC Engineering GA BN45R UT WOS:000081956900041 ER PT S AU Lemoine, FG Rowlands, DD Neumann, GA Smith, DE Pavlis, DE Chinn, DS Luthcke, SB AF Lemoine, FG Rowlands, DD Neumann, GA Smith, DE Pavlis, DE Chinn, DS Luthcke, SB BE Bishop, RH Mackison, DL Culp, RD Evans, MJ TI Precise orbit determination for Mars Global Surveyor during Hiatus and SPO SO SPACEFLIGHT MECHANICS 1999, VOL 102, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th Annual Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID MODEL; ALTIMETER; OBSERVER AB The Mars Global Surveyor (MGS) spacecraft arrived at Mars on September 12, 1997. The Mars Orbiting Laser Altimeter (MOLA) collected data during the Hiatus Phase from October 13 to November 7, 1997, and during the Science Phasing Orbit(SPO)in March to April 1998, and June to July 1998. The Doppler tracking data acquired from the Deep Space Network (DSN) were used to compute orbits for the MOLA Science Team. After development of tuned gravity models to 70x70 in spherical harmonics with the MGS tracking data, the RMS radial orbit difference of overlapping MGS arcs during SPO had an overlap consistency of 30 to 35 m, compared to 160 to 200 m with the a priori GMM-1 solution. We also demonstrate that the use of altimeter crossovers derived from MOLA altimetry improved the MGS orbits in SPO-1 (March 27 - May 1, 1998) by 15 percent (2.8 m) in the radial component, and 60 percent (600 m) in total position. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Lemoine, FG (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 926, Greenbelt, MD 20771 USA. RI Rowlands, David/D-2751-2012; Luthcke, Scott/D-6283-2012; Lemoine, Frank/D-1215-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 37 TC 4 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-458-3 J9 ADV ASTRONAUT SCI PY 1999 VL 102 BP 649 EP 666 PN 1&2 PG 18 WC Engineering, Aerospace SC Engineering GA BN45R UT WOS:000081956900043 ER PT S AU Neelon, JG Proulx, RJ Cefola, PJ Draim, JE AF Neelon, JG Proulx, RJ Cefola, PJ Draim, JE BE Bishop, RH Mackison, DL Culp, RD Evans, MJ TI Orbit determination for medium-altitude eccentric orbits using GPS SO SPACEFLIGHT MECHANICS 1999, VOL 102, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th Annual Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The use of on-board GPS Receivers (GPSR) in the Coarse Acquisition (CA) mode as a measurement source in the orbit determination process previously has been demonstrated for low-altitude, near-circular orbits. However, the utility of GPSR as an orbit determination aid for higher altitude elliptical orbits is more questionable. A major concern is the visibility of a sufficient number of satellites in the GPS constellation, as well as their geometrical spacing, to yield a satisfactory Geometric Dilution of Precision (GDOP) measurement. Another potential concern is the increase of ionosphere delay experienced when viewing GPS satellites lying near the limb of the earth from a nadir facing GPS antenna. This paper extends the scope of earlier studies on the use of actual GPS navigation solutions as a measurement source for several LEO orbits (TOPEX, TAGS, and EUVE). A program was constructed to simulate the GPS navigation solutions for elliptic orbits. The simulation includes realistic error models and visibility considerations. It uses a Message Passing Interface (MPI) parallelprocessing paradigm. Simulated and actual navigation solution errors were compared for the TOPEX case. Ellipse Borealis, the Ellipse Concordia, and Molniya orbit cases were investigated. The simulated measurements were processed with the Goddard Trajectory Determination System (GTDS) orbit determination program. A variety of tests were performed including combinations of realistic measurement errors with perturbation force mis-modeling. It was determined that two hemispherical coverage antennas, one zenith facing and the other nadir-facing, are required to capture signals from sufficient GPS satellites. Continuous GPSR measurements are not required. A repetitive sampling at time intervals of about four minutes appears optimal, with little accuracy to be gained by a more frequent sampling rate. And little accuracy is lost at less frequent sampling, e.g., fifteen minutes. System accuracy was also improved by blocking GPS signals to the nadir-facing antenna from those GPS satellites lying close to the earth's limb. These signals are subject to considerable refraction and distortion from the earth's ionosphere. In summary, the use of an on-board GPS receiver in the orbit determination process appears to be a practical approach, even for highly eccentric earth orbits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Neelon, JG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-458-3 J9 ADV ASTRONAUT SCI PY 1999 VL 102 BP 1213 EP 1236 PN 1&2 PG 24 WC Engineering, Aerospace SC Engineering GA BN45R UT WOS:000081956900076 ER PT S AU Carpenter, JR Schiesser, ER AF Carpenter, JR Schiesser, ER BE Bishop, RH Mackison, DL Culp, RD Evans, MJ TI The importance of semi-major axis knowledge in the determination of near-circular orbits SO SPACEFLIGHT MECHANICS 1999, VOL 102, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th Annual Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, CO SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB In recent years spacecraft designers have increasingly sought to use onboard Global Positioning System receivers for orbit determination. The superb positioning accuracy of GPS has tended to focus more attention on the system's capability to determine the spacecraft's location at a particular epoch than on accurate orbit determination, per se. The determination of orbit plane orientation and orbit shape to acceptable levels is less challenging than the determination of orbital period or semi-major axis. It is necessary to address semi-major axis mission requirements and the GPS receiver capability for orbital maneuver targeting and other operations that require trajectory prediction. Failure to determine semi-major axis accurately can result in a solution that may not be usable for targeting the execution of orbit adjustment and rendezvous maneuvers. Simple formulas, charts, and rules of thumb relating position, velocity, and semi-major axis are useful in design and analysis of GPS receivers for near circular orbit operations, including rendezvous and formation flying missions. Space Shuttle flights of a number of different GPS receivers, including a mix of unfiltered and filtered solution data and Standard and Precise Positioning Service modes, have been accomplished. These results indicate that semi-major axis is often not determined very accurately, due to a poor velocity solution and a lack of proper filtering to provide good radial and speed error correlation. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Carpenter, JR (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 572, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-458-3 J9 ADV ASTRONAUT SCI PY 1999 VL 102 BP 1297 EP 1310 PN 1&2 PG 14 WC Engineering, Aerospace SC Engineering GA BN45R UT WOS:000081956900080 ER PT B AU Williger, GM Francis, PJ Woodgate, BE Malumuth, E AF Williger, GM Francis, PJ Woodgate, BE Malumuth, E BE Hubeny, I Heap, SR Cornett, RH TI On the nature of red galaxies at z=2.38 SO SPECTROPHOTOMETRIC DATING OF STARS AND GALAXIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Spectrophotometric Dating of Stars and Galaxies CY APR 25-29, 1999 CL ANNAPOLIS, MD SP STIS Investigat Team, NASA Goddard Space Flight Ctr AB We present recent results from HST and ground-based observations of the z = 2.38 galaxy cluster 2139-4434. Spectral energy distributions of two galaxies in the cluster with B - K > 6 are consistent with an age > 400 Myr or a formation redshift of z(form) > 5 (q(0) = 0.5, H-0 = 65 km s(-1) Mpc(-1)), with masses in the form of stars similar to 10(11) M.. NICMOS images reveal that one of the galaxies consists of two elliptical galaxies undergoing a merger, which is triggering star formation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Williger, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 5 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-018-8 J9 ASTR SOC P PY 1999 VL 192 BP 171 EP 174 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85K UT WOS:000086435100026 ER PT B AU Landsman, W AF Landsman, W BE Hubeny, I Heap, SR Cornett, RH TI Radiative levitation in hot horizontal branch stars SO SPECTROPHOTOMETRIC DATING OF STARS AND GALAXIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Spectrophotometric Dating of Stars and Galaxies CY APR 25-29, 1999 CL ANNAPOLIS, MD SP STIS Investigat Team, NASA Goddard Space Flight Ctr ID NGC-6752 AB There is now considerable evidence that horizontal branch (HB) stars hotter than about 11,500 Ii experience an enormous enhancement of their photospheric iron abundance due to radiative levitation. In globular clusters, the photospheric iron abundance can reach values of [Fe/H] similar to +0.3, or up to two orders of magnitude higher than the cluster iron abundance. Model atmospheres which take into account the iron overabundance are needed for understanding the appearance of the HE in globular cluster color-magnitude diagrams (CMDs), for the derivation of accurate luminosities, gravities and masses, and for the ultraviolet spectral synthesis of old, metal-poor stellar populations. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Landsman, W (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 681, Greenbelt, MD 20771 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-018-8 J9 ASTR SOC P PY 1999 VL 192 BP 235 EP 238 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85K UT WOS:000086435100036 ER PT B AU Sweigart, AV AF Sweigart, AV BE Hubeny, I Heap, SR Cornett, RH TI The second-parameter effect in metal-rich globular clusters SO SPECTROPHOTOMETRIC DATING OF STARS AND GALAXIES SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on Spectrophotometric Dating of Stars and Galaxies CY APR 25-29, 1999 CL ANNAPOLIS, MD SP STIS Investigat Team, NASA Goddard Space Flight Ctr ID HORIZONTAL-BRANCH STARS; CHEMICAL-COMPOSITION; CCD PHOTOMETRY; ABUNDANCES; HALO AB Recent Hubble Space Telescope (HST) observations by Rich et al. (1997) have shown that the metal-rich globular clusters (GCs) NGC 6388 and NGC 6441 exhibit a pronounced 2nd parameter effect. Ordinarily metal-rich GCs have only a red horizontal-branch (HB) clump. However, NGC 6388 and NGC 6441 also possess an unexpected population of blue HE stars, indicating that some 2nd parameter is operating in these clusters. Quite remarkably, the HBs in both clusters slope upward with decreasing B-V from the red clump to the top of the blue tail. We review the results of ongoing stellar evolution calculations which indicate 1) that NGC 6388 and NGC 6441 might provide a crucial diagnostic for understanding the origin of the 2nd parameter effect, 2) that differences in age or mass loss along the red-giant branch (RGB) - the two most prominent 2nd parameter candidates - cannot explain the HE morphology of these GCs, and 3) that noncanonical effects involving an enhanced helium abundance or rotation can produce upward sloping HBs. Finally we suggest a new metal-depletion scenario which might help to resolve a baffling conundrum concerning the surface gravities of the blue KB stars in these clusters. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sweigart, AV (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. EM sweigart@bach.gsfc.nasa.gov NR 34 TC 8 Z9 8 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-018-8 J9 ASTR SOC P PY 1999 VL 192 BP 239 EP 248 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85K UT WOS:000086435100037 ER PT B AU Fioc, M AF Fioc, M BE Hubeny, I Heap, SR Cornett, RH TI A statistical study of nearby galaxies: NIR growth curves and optical-to-NIR colors as a function of type, luminosity and inclination SO SPECTROPHOTOMETRIC DATING OF STARS AND GALAXIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Spectrophotometric Dating of Stars and Galaxies CY APR 25-29, 1999 CL ANNAPOLIS, MD SP STIS Investigat Team, NASA Goddard Space Flight Ctr ID MAGNITUDE AB Near-infrared (NIR) growth curves of the magnitude as a function of the aperture have been built and used to compute total NIR magnitudes and optical-to-NIR colors for a large sample of galaxies. A statistical analysis of the colors as a function of type, intrinsic luminosity and inclination or shape has been carried out (Fioc & Rocca-Volmerange 1999). We stress in particular the importance of using integrated colors. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fioc, M (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-018-8 J9 ASTR SOC P PY 1999 VL 192 BP 299 EP 302 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85K UT WOS:000086435100044 ER PT B AU Brown, TM AF Brown, TM BE Hubeny, I Heap, SR Cornett, RH TI Measurements of the UV upturn in local and intermediate-redshift ellipticals SO SPECTROPHOTOMETRIC DATING OF STARS AND GALAXIES SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on Spectrophotometric Dating of Stars and Galaxies CY APR 25-29, 1999 CL ANNAPOLIS, MD SP STIS Investigat Team, NASA Goddard Space Flight Ctr ID HOPKINS-ULTRAVIOLET-TELESCOPE; EVOLVED STELLAR POPULATIONS; GIANT BRANCH; GALAXIES; CLUSTERS; PHOTOMETRY; EVOLUTION; RADIATION AB The rest-frame ultraviolet contains the most sensitive indicators of age for elliptical galaxies. While the near-UV flux from young ellipticals isolates the main sequence turnoff, the far-UV flux in old ellipticals is dominated by hot horizontal branch (HB) stars. This evolved population was first revealed by early UV observations showing a sharp flux increase shortward of rest-frame 2500 Angstrom, subsequently dubbed the "UV upturn." The phenomenon has since been characterized in many local ellipticals, and measurements at intermediate redshifts are now underway. Once ellipticals reach ages of 5-10 Gyr, stellar and galactic evolution theories predict that the UV-to-optical flux ratio can increase by orders of magnitude over timescales of a few Gyr, making the UV upturn the most rapidly evolving feature of these galaxies. It is thus expected to fade dramatically with increasing redshift. I review the imaging and spectroscopic evidence for the nature of the UV upturn in nearby ellipticals, and then present observations that measure the UV upturn at an epoch significantly earlier than our own. Far-UV data from the Hopkins Ultraviolet Telescope demonstrate that the spectra of nearby ellipticals are dominated by hot HE stars. Faint Object Camera UV imaging of M32 and the M31 bulge detected the UV-bright phases of post-MB stars, but did not reach the HE itself. Recent Space Telescope Imaging Spectrograph observations were the first to image the hot HE and post-MB stars in the center of the nearest elliptical galaxy, M32; these observations also show a striking lack of UV-bright post-AGE stars. Faint Object Camera observations of Abell 370, a rich galaxy cluster at z = 0.375, show that giant ellipticals at a lookback time of 4 Gyr can exhibit strong UV luminosity, with no evidence of evolution in the UV upturn between this epoch and our own, thus implying a high redshift of formation (z(f) greater than or equal to 4). C1 NASA, Goddard Space Flight Ctr, NOAO, Greenbelt, MD 20771 USA. RP Brown, TM (reprint author), NASA, Goddard Space Flight Ctr, NOAO, Greenbelt, MD 20771 USA. EM tbrown@pulsar.gsfc.nasa.gov NR 30 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-018-8 J9 ASTR SOC P PY 1999 VL 192 BP 315 EP 323 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85K UT WOS:000086435100048 ER PT B AU Loewenstein, M AF Loewenstein, M BE Cepa, J Carral, P TI Dark matter and metal abundances in elliptical galaxies from X-ray observations of the hot ISM SO STAR FORMATION IN EARLY-TYPE GALAXIES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Star Formation in Early-Type Galaxies CY JUN 29-JUL 03, 1998 CL GUANAJUATO, MEXICO SP Astron Soc Pacific ID ENRICHMENT; CLUSTERS; SAMPLE; ASCA AB I review the results of recent analysis and interpretation of X-ray observations of elliptical galaxies, focusing on elemental abundances and dark matter. The hot ISM is characterized by subsolar Fe abundances and solar Si-to-Fe ratios; and, I compare these with stellar abundances and discuss implications of these measurements. From models constructed to explain X-ray temperatures and their correlation with optical properties in a complete sample of ellipticals, I demonstrate the ubiquity of dark matter in L > L-* galaxies, present limits on dark matter structural parameters, and discuss the scaling of dark halos with optical luminosity. The mass-to-light ratio within 6R(e) has a universal value, M/L-V approximate to 25h(80)M./L-V., that conflicts with the simplest extension of CDM theories of large scale structure formation to galactic scales. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RP Loewenstein, M (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20770 USA. NR 29 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-84-8 J9 ASTR SOC P PY 1999 VL 163 BP 153 EP 168 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN27V UT WOS:000081412300016 ER PT S AU Brown, TM Ferguson, HC Stanford, SA Deharveng, JM AF Brown, TM Ferguson, HC Stanford, SA Deharveng, JM BE Whitelock, P Cannon, R TI Color-luminosity relations for the resolved hot stellar populations in the centers of M31 and M32 SO STELLAR CONTENT OF LOCAL GROUP GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 192nd Symposium of the International-Astronomical-Union CY SEP 07-11, 1998 CL CAPE TOWN, SOUTH AFRICA SP Int Astron Union, S Africa Observ, Abdus Salam Int Ctr Theoret Phys, Univ Cape Town, AngloGold Corp, Fdn Res Dev ID ELLIPTIC GALAXIES; ULTRAVIOLET; EVOLUTION; ORIGIN; STARS AB We present Faint Object Camera (FOC) ultraviolet images of the central 14 x 14" of Messier 31 and Messier 32. The hot stellar population detected in the composite UV spectra of these galaxies is partially resolved into stars, and we measure their colors and apparent magnitudes. We detect 433 stars in M31 and 138 stars in M32, down to limits of m(F275W) = 25.5 mag and m(F175W) = 24.5 mag. We investigate the luminosity functions of the sources, their spatial distribution, their color-magnitude diagrams, and their total integrated far-UV flux. Although M32 has a weaker UV upturn than M31, the luminosity functions and color-magnitude diagrams of M31 and M32 are surprisingly similar, and are inconsistent with a majority contribution from any of the following: post-AGB stars more massive than 0.56 Mcircle dot, main sequence stars, or blue stragglers. The luminosity functions and color-magnitude diagrams are consistent with a dominant population of stars evolving from the extreme horizontal branch (EHB) along tracks of mass 0.47-0.53 Mcircle dot. These stars are well below the detection limits of our images while on the zero-age EHB, but become detectable while in the more luminous (but shorter) post-HB phases. Our observations require that only a very small fraction of the main sequence population (2% in M31 and 0.5% in M32) in these two galaxies evolve though the EHB and post-EHB phases, with the remainder rapidly evolving through bright post-AGB evolution with few resolved stars expected in the small field of view covered by the FOC. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. RP Brown, TM (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-886733-82-1 J9 IAU SYMP PY 1999 IS 192 BP 195 EP 202 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU33A UT WOS:000175705000027 ER PT S AU Grebel, EK Kolatt, T Brandner, W AF Grebel, EK Kolatt, T Brandner, W BE Whitelock, P Cannon, R TI Orbits versus star formation histories: A progress report SO STELLAR CONTENT OF LOCAL GROUP GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 192nd Symposium of the International-Astronomical-Union CY SEP 07-11, 1998 CL CAPE TOWN, SOUTH AFRICA SP Int Astron Union, S Africa Observ, Abdus Salam Int Ctr Theoret Phys, Univ Cape Town, AngloGold Corp, Fdn Res Dev ID GALAXIES AB Milky Way dwarf companions and satellites of distant spirals seem to show a preference for polar orbits. We suggest that five out of six M31 dwarf spheroidal companions as well as two dwarf irregulars may also be located near a polar plane. We briefly discuss preliminary results from a statistical approach to study correlations between star formation histories and orbits of Local Group dwarf galaxies, such as a possible correlation between star formation episodes and galaxy separations. C1 Univ Calif Santa Cruz, UCO, Lick Observ, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. IPAC, JPL, Pasadena, CA 91125 USA. RP Grebel, EK (reprint author), Univ Calif Santa Cruz, UCO, Lick Observ, Santa Cruz, CA 95064 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-886733-82-1 J9 IAU SYMP PY 1999 IS 192 BP 447 EP 450 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU33A UT WOS:000175705000062 ER PT J AU Andrews, R Mah, R Aghevli, A Freitas, K Galvagni, A Guerrero, M Papsin, R Reed, C Stassinopoulos, D AF Andrews, R Mah, R Aghevli, A Freitas, K Galvagni, A Guerrero, M Papsin, R Reed, C Stassinopoulos, D TI Multimodality stereotactic brain tissue identification: The NASA smart probe project SO STEREOTACTIC AND FUNCTIONAL NEUROSURGERY LA English DT Article; Proceedings Paper CT Meeting of the American-Society-for-Stereotactic-and-Functional-Neurosurgery CY JUL 08-10, 1999 CL SNOWBIRD, UTAH SP Amer Soc Stereotact & Funct Neurosurg DE brain tissue; computer; neural network; spectroscopy AB Real-time tissue identification can benefit procedures such as stereotactic brain biopsy, functional neurosurgery and brain tumor excision. Optical scattering spectroscopy has been shown to be effective at discriminating cancer from noncancerous conditions in the colon, bladder and breast. The NASA Smart Probe extends the concept of 'optical biopsy' by using neural network techniques to combine the output from 3 microsensors contained within a cannula 2.7 mm in diameter (i.e. the diameter of a stereotactic brain biopsy needle), Experimental data from 5 rats show the clear differentiation between tissues such as brain, nerve, fat, artery and muscle that can be achieved with optical scattering spectroscopy alone. These data and previous findings with other modalities such as (1) analysis of the image from a fiberoptic neuroendoscope and (2) the output from a microstrain gauge suggest the Smart Probe multiple microsensor technique shows promise for real-time tissue identification in neurosurgical procedures. Copyright (C) 2000 S. Karger AG, Basel. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Texas Tech Univ, Hlth Sci Ctr, Div Neurosurg, El Paso, TX 79905 USA. NR 7 TC 11 Z9 11 U1 1 U2 1 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 1011-6125 J9 STEREOT FUNCT NEUROS JI Stereotact. Funct. Neurosurg. PY 1999 VL 73 IS 1-4 BP 1 EP 8 DI 10.1159/000029742 PG 8 WC Neurosciences; Neuroimaging; Surgery SC Neurosciences & Neurology; Surgery GA 326HN UT WOS:000087727900001 PM 10853089 ER PT B AU Brown, AM Ferri, AA AF Brown, AM Ferri, AA BE Spencer, BF Johnson, EA TI Applying the Probabilistic Dynamic Synthesis method to a realistic structure SO STOCHASTIC STRUCTURAL DYNAMICS LA English DT Proceedings Paper CT 4th International Conference on Stochastic Structural Dynamics (SSD 98) CY AUG 06-08, 1998 CL NOTRE DAME, IN SP US Natl Sci Fdn, Univ Notre Dame ID RELIABILITY AB The Probabilistic Dynamic Synthesis (PDS) method is a technique for obtaining the statistics of a desired response engineering quantity for a structure with nondeterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. In previous work, the feasibility of the PDS method applied to a simple seven degree-of-freedom(dof) spring-mass system was verified. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered. C1 NASA, George C Marshall Space Flight Ctr, Struct & Dynam Lab, Huntsville, AL 35812 USA. RP Brown, AM (reprint author), NASA, George C Marshall Space Flight Ctr, Struct & Dynam Lab, Huntsville, AL 35812 USA. NR 15 TC 0 Z9 0 U1 0 U2 1 PU A A BALKEMA PUBLISHERS PI LEIDEN PA SCHIPHOLWEG 107C, PO BOX 447, 2316 XC LEIDEN, NETHERLANDS BN 90-5809-024-8 PY 1999 BP 421 EP 428 PG 8 WC Engineering, Aerospace; Engineering, Marine; Engineering, Civil; Engineering, Mechanical; Mathematics, Applied; Mechanics SC Engineering; Mathematics; Mechanics GA BM94G UT WOS:000080198100058 ER PT B AU Sahu, MS AF Sahu, MS BE Gibson, BK Putman, ME TI The high velocity cloud HVC 487 and its relationship to magellanic stream gas SO STROMLO WORKSHOP ON HIGH-VELOCITY CLOUDS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Stromlo Workshop on High-Velocity Clouds CY AUG 14-15, 1998 CL CANBERRA, AUSTRALIA SP Astron Soc Pacific ID INTERSTELLAR ABSORPTION-LINES; GALAXY NGC-1705 AB The line-of-sight to the H I-rich dwarf galaxy NGC 1705 intercepts the high velocity cloud HVC 487. The (Si/H) ratio (> 0.6(Si/H).) and low dust depletion derived for HVC 487 from archival GHRS data are consistent with an association with Magellanic Stream gas. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sahu, MS (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-87-2 J9 ASTR SOC P PY 1999 VL 166 BP 84 EP 87 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN45A UT WOS:000081943100008 ER PT B AU Sundaresan, MJ Ghoshal, A Schulz, MJ Ferguson, F Pai, PF Chung, JH AF Sundaresan, MJ Ghoshal, A Schulz, MJ Ferguson, F Pai, PF Chung, JH BE Chang, FK TI Crack detection using a scanning laser vibrometer SO STRUCTURAL HEALTH MONTORING 2000 LA English DT Proceedings Paper CT 2nd International Workshop on Structural Health Monitoring CY SEP 08-10, 1999 CL STANFORD UNIV, STANFORD, CA SP USAF Off Sci Res, USA Res Off, Fed Highway Adm, Natl Sci Fdn HO STANFORD UNIV AB A vibration measurement technique is presented to detect cracks on the inside of an aircraft wing box and other structures without disassembly of any components. A simulation was performed using a simple beam model and damage was detected using operational deflection shapes. An experiment was performed in which piezoceramic patch actuators were bonded onto the outer surface of an aircraft wing panel to excite high-frequency vibration, and a scanning laser doppler vibrometer was used to measure the vibration response of the outer surface. A notch in the form of a saw cut was introduced to simulate a crack on an inside stiffener of the wing panel. Extensive testing at different frequency ranges and scan spatial densities was performed, and operational deflection shapes and frequency response functions were computed from the laser velocity measurements. The saw cut notch was detected by comparing the responses in the healthy and damaged conditions. Guidelines on using the technique are presented. C1 N Carolina Agr & Technol State Univ, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. RP Sundaresan, MJ (reprint author), N Carolina Agr & Technol State Univ, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-881-0 PY 1999 BP 936 EP 945 PG 10 WC Engineering, Aerospace; Engineering, Civil; Instruments & Instrumentation; Materials Science, Characterization & Testing SC Engineering; Instruments & Instrumentation; Materials Science GA BP03P UT WOS:000083947300092 ER PT B AU Kraemer, SB Crenshaw, DM Turner, TJ George, IM AF Kraemer, SB Crenshaw, DM Turner, TJ George, IM BE Gaskell, CM Brandt, WN Dietrich, M DultzinHacyan, D Eracleous, M TI Narrow emission lines and the spectral energy distribution in Seyfert galaxies SO STRUCTURE AND KINEMATICS OF QUASAR BROAD LINE REGIONS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Structure and Kinematics of Quasar Broad Line Regions CY MAR 23-26, 1998 CL LINCOLN, NE SP Astron Soc Pacific ID SOFT-X-RAY; ACTIVE GALACTIC NUCLEI; ULTRAVIOLET OBSERVATIONS; QUASARS; REGION; CLOUDS; BUMP AB We explore the relationship between the relative strengths of emission Lines formed in the narrow line regions of Seyfert galaxies and the shape of the EUV continuum radiation emitted by the active galactic nucleus. We find a correlation between the narrow He II lambda 4686/H beta ratio, and the [O III] lambda 5007/[O II] lambda 3727 ratio. Also, within a sample of Seyfert 1.5s, objects with flatter soft X-ray slopes tend to have lower values of He II lambda 4686/H beta. These results indicate that the narrow emission line strengths are sensitive to the shape of the EUV continuum. However, it is most plausible that the differences are an indication of the size of the columns of absorbing material internal to the narrow line region, rather than intrinsic differences in continuum shape. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kraemer, SB (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-97-X J9 ASTR SOC P PY 1999 VL 175 BP 315 EP 320 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP16L UT WOS:000084260300043 ER PT B AU Crenshaw, DM Kraemer, SB AF Crenshaw, DM Kraemer, SB BE Gaskell, CM Brandt, WN Dietrich, M DultzinHacyan, D Eracleous, M TI Properties of the UV absorbers in Seyfert 1 galaxies SO STRUCTURE AND KINEMATICS OF QUASAR BROAD LINE REGIONS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Meeting on Structure and Kinematics of Quasar Broad Line Regions CY MAR 23-26, 1998 CL LINCOLN, NE SP Astron Soc Pacific ID C-IV ABSORPTION; X-RAY; NGC-3516 AB We have retrieved FOS and GHRS UV spectra of Seyfert 1 galaxies from the HST data archive, to study a poorly understood component of active galaxies: intrinsic UV absorption. We find that about 50% of Seyfert 1 galaxies show absorption Lines that are intrinsic to the active nucleus, compared to previous estimates of 3-10% from IUE spectra. Recent studies indicate that about half of all Seyfert 1 galaxies also exhibit X-ray "warm absorbers", characterized by O VII and O VIII absorption edges. The discovery of frequent UV and X-ray absorption suggests that an important physical component has been missing in our efforts to understand active galaxies. Our analysis of the HST data shows that the absorbers are typically characterized by high ionization (C IV, N V), blueshifts relative to systemic velocity (indicating outflow), multiple kinematic components, broad widths (100-300 km s(-1)), and variability on time scales of months or years. It appears that there is a one-to-one correspondence between the presence of UV absorbers and X-ray warm absorbers, although the notion that the absorbers arise in the same zone, characterized by a single ionization parameter, is still controversial. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crenshaw, DM (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. EM crenshaw@buckeye.gsfc.nasa.gov; stiskraemer@yancey.gsfc.nasa.gov NR 12 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-97-X J9 ASTR SOC P PY 1999 VL 175 BP 341 EP 346 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP16L UT WOS:000084260300047 ER PT S AU Poland, AI AF Poland, AI BE Burch, JL Carovillano, RL Antiochos, SK TI The SOHO mission SO SUN-EARTH PLASMA CONNECTIONS SE GEOPHYSICAL MONOGRAPH SERIES LA English DT Proceedings Paper CT Toward Solar Max 2000 - The Present Achievements and Future Opportunities of ISTP and GEM Workshop CY FEB 10-13, 1998 CL YOSEMITE NATL PARK, CA ID TRANSITION REGION; QUIET-SUN; CORONA AB The Solar and Heliospheric Observatory (SOHO) is primarily the solar observing portion of the International Solar Terrestrial Physics (ISTP) mission but includes some particle detecting experiments. This paper describes some selected results from the interior studies, the transition region observations, and the outer coronal observations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Poland, AI (reprint author), NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0065-8448 BN 0-87590-092-5 J9 GEOPH MONOG SERIES PY 1999 VL 109 BP 11 EP 17 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics GA BN13C UT WOS:000080795900002 ER PT S AU Thompson, BJ St Cyr, OC Plunkett, SP Gurman, JB Gopalswamy, N Hudson, HS Howard, RA Michels, DJ Delaboudiniere, JP AF Thompson, BJ St Cyr, OC Plunkett, SP Gurman, JB Gopalswamy, N Hudson, HS Howard, RA Michels, DJ Delaboudiniere, JP BE Burch, JL Carovillano, RL Antiochos, SK TI The correspondence of EUV and white light observations of coronal mass ejections with SOHO EIT and LASCO SO SUN-EARTH PLASMA CONNECTIONS SE GEOPHYSICAL MONOGRAPH SERIES LA English DT Proceedings Paper CT Toward Solar Max 2000 - The Present Achievements and Future Opportunities of ISTP and GEM Workshop CY FEB 10-13, 1998 CL YOSEMITE NATL PARK, CA ID SOLAR-FLARE; SMM OBSERVATIONS; MAGNETIC-FLUX; EVENTS; TRANSIENTS; GEOMETRY; FILAMENT; MISSION; SPEEDS; MODEL AB For over two years of operation, the LASCO coronagraph and the EIT imaging telescope have conducted observing campaigns intending to provide continuous coverage of global coronal dynamic phemonena. These compatible observations, which we call the "CME Watch," have been used to further our understanding of CME initiation and propagation, and to provide advance warning of potential Earth-impacting eruptions. This paper includes a discussion of the EUV signatures of CME's in the inner corona and attempts to optimally combine the EUV and white light observations. One result of this effort is the determination that it is highly likely that LASCO definitively observes the vast majority of coronal mass ejections. While previous coronagraph missions have not been sensitive enough to detect weak eruptions, LASCO is capable of imaging even the faint "halo" CME's, which are our most accurate indicator of geospace-impacting eruptions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thompson, BJ (reprint author), NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012; Thompson, Barbara/C-9429-2012 NR 56 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0065-8448 BN 0-87590-092-5 J9 GEOPH MONOG SERIES PY 1999 VL 109 BP 31 EP 46 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics GA BN13C UT WOS:000080795900004 ER PT S AU Moore, TE Chandler, MO Chappell, CR Comfort, RH Craven, PD Delcourt, DC Elliott, HA Giles, BL Horwitz, JL Pollock, CJ Su, YJ AF Moore, TE Chandler, MO Chappell, CR Comfort, RH Craven, PD Delcourt, DC Elliott, HA Giles, BL Horwitz, JL Pollock, CJ Su, YJ BE Burch, JL Carovillano, RL Antiochos, SK TI Polar TIDE results on polar ion outflows SO SUN-EARTH PLASMA CONNECTIONS SE GEOPHYSICAL MONOGRAPH SERIES LA English DT Proceedings Paper CT Toward Solar Max 2000 - The Present Achievements and Future Opportunities of ISTP and GEM Workshop CY FEB 10-13, 1998 CL YOSEMITE NATL PARK, CA ID WIND AB The ISTP Polar spacecraft is equipped with a unique plasma velocity analyzer system designed specifically for kinetic diagnostics of low-energy, low-density plasma ions. Such plasmas were previously unobservable in the polar cap region owing to their low velocities and the positive photoelectric charging of spacecraft in sunlight at low ambient plasma density. The thermal ion dynamics experiment (TIDE) incorporates seven large apertures, focusing electrostatic optics, and time-of-flight mass analysis, for enhanced sensitivity to low energy plasma ions. The plasma source instrument (PSI) limits and regulates the photoelectric charging of the Polar spacecraft at small potentials (similar to+2V). Together, TIDE and PSI have produced new observations of i) the mixing of solar and ionospheric plasmas in the cleft regions; ii) auroral heating and plasma transport; iii) solar illumination control of the polar cap ionosphere; iv) the downward motion of O+ at lower altitudes throughout the polar cap region; v) the high altitude polar wind; vi) the high altitude convection of the polar outflows; vii) the unexpected dynamism of polar wind outflows; and viii) the supply of plasma to the plasma sheet. These observations indicate that most polar cap O+ out flow originates in the dayside plasma upwelling region, creating a plasma fountain effect in the polar cap. The observations support the evaluation of consequences of the ionospheric source of plasma for magnetospheric dynamics and storm phenomena. Preliminary global modeling results indicate that ionospheric plasma is the dominant contributor to both the density and pressure of the plasma within a corresponding geopause that extends to the persistent neutral line in the central plasma sheet. TIDE and PSI have contributed fundamentally to our knowledge that the dissipation of solar wind energy is not limited to the ionosphere proper, but is distributed throughout a much larger geosphere of dominantly terrestrial origin. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Moore, TE (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692, Greenbelt, MD 20771 USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 23 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0065-8448 BN 0-87590-092-5 J9 GEOPH MONOG SERIES PY 1999 VL 109 BP 87 EP 101 PG 15 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Physics GA BN13C UT WOS:000080795900009 ER PT J AU Spalvins, T AF Spalvins, T TI Improvement of ion plated Ag and Au film adhesion to Si3N4 and SiC surfaces for increased tribological performance SO SURFACE ENGINEERING LA English DT Article ID ALUMINA; OXIDE AB A modified dc diode plating system, utilising a metallic scr een cage as a cathode and designated screen cage ion plating, is used to deposit Ag and Au lubricating films on Si3N4 and SiC surfaces. When deposition is performed in Ar or N-2 glow discharge, the surface displays poor adhesive strength (<5 MPa). A dramatic increase in adhesive strength (>80 MPa) is achieved when plating is performed in a reactive 500(2)-50Ar glow discharge. The excited/ionised oxygen species (O-2(+)/O+) in the glow discharge contribute to the oxidation of the Si3N4 or SiC surfaces as determined by X-ray photoelectron spectroscopy depth profiling. The reactively sputter oxidised Si3N4 or SiC surfaces and the activated oxidised metastable Ag or Au species formed in the plasma, cooperatively contribute to the increased adhesion. As a result, the linear thermal expansion coefficient mismatch at the interface is reduced. These lubricating Ag and Au films under sliding conditions reduce the friction coefficient by a factor of 2.5-4. (C) 1999 IoM Communications Ltd. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Spalvins, T (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 23-2, Cleveland, OH 44135 USA. NR 14 TC 1 Z9 1 U1 1 U2 3 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON SW1Y 5DB, ENGLAND SN 0267-0844 J9 SURFACE ENG JI Surf. Eng. PY 1999 VL 15 IS 4 BP 317 EP 320 DI 10.1179/026708499101516678 PG 4 WC Materials Science, Coatings & Films SC Materials Science GA 238NL UT WOS:000082716300009 ER PT B AU Miyoshi, K AF Miyoshi, K BE Kumar, A Chung, YW Moore, JJ Smugeresky, JE TI Surface design and engineering toward wear-resistant, self-lubricating diamond films and coatings SO SURFACE ENGINEERING: SCIENCE AND TECHNOLOGY I LA English DT Proceedings Paper CT Symposium on Surface Engineering - Science and Technology I held at the 1999 TMS Annual Meeting CY FEB 28-MAR 04, 1999 CL SAN DIEGO, CA SP Minerals Met & Mat Soc, Mat Proc & Mfg Div AB The tribological properties of chemical-vapor-deposited (CVD) diamond films vary with the environment, possessing a Jekyll-and-Hyde character. CVD diamond has low coefficient of friction and high wear resistance in air but high coefficient of friction and low wear resistance in vacuum. Improving the tribological functionality of materials (such as achieving low friction and good wear resistance) was an aim of this investigation. Three studies on the surface design, surface engineering, and tribology of CVD diamond have shown that its friction and wear are significantly reduced in ultrahigh vacuum. The main criteria for judging whether diamond films are an effective wear-resistant, self-lubricating material were coefficient of friction and wear rate, which must be less than 0.1 and on the order of 10(-6) mm(3)/ Nm, respectively. In the first study the presence of a thin film (<1 mu m thick) of amorphous, nondiamond carbon (hydrogenated carbon, also called diamondlike carbon or DLC) on CVD diamond greatly decreased the coefficient of friction and the wear rate. Therefore, a thin DLC film on CVD diamond can be an effective wear-resistant, lubricating coating in ultrahigh vacuum. In the second study the presence of an amorphous, nondiamond carbon surface layer formed on CVD diamond by ion implantation significantly reduced the coefficient of friction and the wear rate in ultrahigh vacuum. Therefore, such surface layers are acceptable for effective self-lubricating, wear-resistant applications of CVD diamond. In the third study CVD diamond in contact with cubic boron nitride exhibited low coefficient of friction in ultrahigh vacuum. Therefore, this materials combination can provide an effective self-lubricating, wear-resistant couple in ultrahigh vacuum. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Miyoshi, K (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 19 TC 0 Z9 0 U1 1 U2 1 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-427-5 PY 1999 BP 307 EP 317 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science; Metallurgy & Metallurgical Engineering GA BM95J UT WOS:000080238600028 ER PT S AU Bilbro, JW AF Bilbro, JW BE Atansov, PA Stoyanov, DV TI Next Generation Space Telescope ultra-lightweight mirror program SO TENTH INTERNATIONAL SCHOOL ON QUANTUM ELECTRONICS: LASER PHYSICS AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 10th International School on Quantum Electronics - Laser Physics and Applications CY SEP 21-25, 1998 CL VARNA, BULGARIA SP SPIE, SPIE Bulgaria Chapter, Bulgaria Acad Sci, Inst Electr AB The Next Generation Space Telescope(1) (NGST) is currently envisioned as an eight meter diameter cryogenic deployable telescope that will operate at the earth sun libration point L2. A number of different designs are being examined within NASA and under industry studies by Ball Aerospace, Lockheed-Martin and TRW. Although these designs differ in many respects, they all require significant advancements in the state-of-the-art with respect to large diameter, ultra-lightweight, mirrors. The purpose of this paper is to provide insight into the current status of the mirror development program. C1 NASA, George C Marshall Space Flight Ctr, Astrion Lab, Huntsville, AL 35812 USA. RP Bilbro, JW (reprint author), NASA, George C Marshall Space Flight Ctr, Astrion Lab, Huntsville, AL 35812 USA. NR 1 TC 4 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3034-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3571 BP 26 EP 31 DI 10.1117/12.347615 PG 6 WC Engineering, Electrical & Electronic; Remote Sensing; Optics; Spectroscopy SC Engineering; Remote Sensing; Optics; Spectroscopy GA BN13S UT WOS:000080848500003 ER PT S AU Alexander, CD Carlstrom, JE AF Alexander, CD Carlstrom, JE BE Hwu, RJ Wu, K TI Demonstration of an image rejection mixer for high frequency applications (26-36 GHz) SO TERAHERTZ AND GIGAHERTZ PHOTONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Terahertz and Gigahertz Photonics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE DE image rejection mixer; high frequency; cryogenic mixer AB A new high frequency image-rejection mixer was successfully developed and tested in a 26-36 GHz band receiver. This paper describes the receiver system, the operation of the image rejection mixer, and presents test results for the mixer at ambient and cryogenic temperatures. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Alexander, CD (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3281-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3795 BP 74 EP 83 DI 10.1117/12.370152 PG 10 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BP33W UT WOS:000084753700009 ER PT S AU Mehdi, I Schlecht, E Arzumanyan, A Bruston, J Siegel, P Smith, RP Pearson, J Martin, S Porterfield, D AF Mehdi, I Schlecht, E Arzumanyan, A Bruston, J Siegel, P Smith, RP Pearson, J Martin, S Porterfield, D BE Hwu, RJ Wu, K TI Development of millimeter and submillimeter-wave local oscillator circuits for a space telescope SO TERAHERTZ AND GIGAHERTZ PHOTONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Terahertz and Gigahertz Photonics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE AB FIRST (Far InfraRed and Submillimetre Telescope) is a European science mission that will perform photometry and spectroscopy in the 80-670 mu m range. The proposed heterodyne instrument for FIRST is a seven-channel receiver, which combines the high spectral resolving capability (0.3-300km/s) of the radio heterodyne technique with the low noise detection offered by Superconductor-Insulator-Superconductor (SIS) and Hot Electron Bolometer (HEB) mixers. It is designed to provide almost continuous frequency coverage from 480-2700 GHz. The Jet Propulsion Laboratory is responsible for developing and implementing the local oscillator sources for the 1200-2700 GHz mixers. The present state-of-the-art approach for millimeter-wave multipliers, based on waveguide blocks and discretely mounted devices, becomes harder and harder to implement as the frequency range is extended beyond 300 GHz. This talk will focus on the technology that is being developed to enhance and extend planar integrated Schottky devices and circuits to meet mission local oscillator requirements. The baseline approach is to use GaAs power amplifiers from 71 to 115 GHz followed by a series of planar Schottky diode varactor multiplier stages to generate the required LO signal. The circuits have to be robust, relatively easy to assemble, and must provide broad fix-tuned bandwidth. A number of new technology initiatives being implemented to achieve these goals will be discussed. Approaches include quartz-based and substrate-less diode circuitry and integrated GaAs membrane technology. Recent results and progress-to-date will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mehdi, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 6 Z9 6 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3281-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3795 BP 329 EP 337 DI 10.1117/12.370180 PG 9 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BP33W UT WOS:000084753700035 ER PT S AU Gaidis, MC Anderson, MS Harding, DG AF Gaidis, MC Anderson, MS Harding, DG BE Hwu, RJ Wu, K TI A calibration target for far-infrared spaceborne applications SO TERAHERTZ AND GIGAHERTZ PHOTONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Terahertz and Gigahertz Photonics CY JUL 19-23, 1999 CL DENVER, CO SP SPIE DE calibration target; far-infrared; spaceborne; 2.5 THz; black body; absorber; submillimeter; terahertz; radiometer AB We describe progress in the development of a calibration target for use in the EOS-MLS 2.5 THz radiometer on NASA's CHEM-I spacecraft. Although the intended use is as a stable, isothermal black body load at a frequency of 2.5 THz,the design is suitable for use throughout the far-infrared (FIR). A wedge design is used for the target body to enhance the emissivity to desired levels at 2.5 THz. The body is machined from aluminum, giving the best trade between issues such as cost, thermal conductivity, mass, and strength. The target utilizes a white coating to reduce the destabilizing effects of periodic solar illumination. The coating can be made relatively thin to allow accurate temperature measurements of the FIR-absorbing medium. Emissivity of greater than 0.99 is achieved at 2.5 THz, while the solar absorptance is estimated at < 0.5. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaidis, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Gaidis, Michael/D-3327-2013 NR 11 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3281-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3795 BP 348 EP 356 DI 10.1117/12.370182 PG 9 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BP33W UT WOS:000084753700037 ER PT S AU Pickett, HM AF Pickett, HM BE Sherwin, MS TI THz spectroscopy of the atmosphere SO TERAHERTZ SPECTROSCOPY AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Terahertz Spectroscopy and Applications CY JAN 25-26, 1999 CL SAN JOSE, CA SP SPIE, US Army Res Off, Def Adv Res Projects Agnecy DE THz; atmosphere; stratosphere; heterodyne AB THz spectroscopy of the atmosphere has been driven by the need to make remote sensing measurements of OH. While the THz region can be used for sensitive detection on many atmospheric molecules, the THz region is the best region for measuring the diurnal behavior of stratospheric OH by remote sensing. The infrared region near 3 mu m suffers from chemiluminescence and from spectral contamination due to water. The ultraviolet region near 300 nm requires solar illumination. The three techniques for OH emission measurements in the THz region include Fourier Transform interferometry, Fabry-Perot interferometry, and heterodyne radiometry. The first two use cryogenic direct detectors while the last technique uses a local oscillator and a mixer to down convert the THz signal to GHz frequencies. All techniques have been used to measure stratospheric OH from balloon platforms. OH results from the Fabry-Perot based FILOS instrument will be given. Heterodyne measurement of OH at 2.5 THz has been selected to be a component of the Microwave Limb Sounder on the Earth Observing System CHEM-1 polar satellite. The design of this instrument will be described. A balloon-based prototype heterodyne 2.5 THz radiometer had its first flight on 24 May 1998. Results form this flight will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pickett, HM (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-701, Pasadena, CA 91109 USA. NR 6 TC 4 Z9 4 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3087-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3617 BP 2 EP 6 DI 10.1117/12.347109 PG 5 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Spectroscopy SC Engineering; Optics; Physics; Spectroscopy GA BN09R UT WOS:000080659300001 ER PT S AU McGrath, WR Karasik, BS Skalare, A Wyss, R Bumble, B LeDuc, HG AF McGrath, WR Karasik, BS Skalare, A Wyss, R Bumble, B LeDuc, HG BE Sherwin, MS TI Hot-electron superconductive mixers for THz frequencies SO TERAHERTZ SPECTROSCOPY AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Terahertz Spectroscopy and Applications CY JAN 25-26, 1999 CL SAN JOSE, CA SP SPIE, US Army Res Off, Def Adv Res Projects Agnecy DE submillimeter; heterodyne; mixer; hot electron bolometer; terahertz; superconductor; far infrared ID TEMPERATURE-GROWN GAAS; BOLOMETRIC MIXERS; LOW-NOISE; BANDWIDTH; PHOTOMIXERS; POWER; GAIN AB Superconductive hot-electron bolometer (HEB) mixers have been built and tested in the frequency range from 1.1 THz to 2.5 THz. The mixer device employs diffusion as a cooling mechanism for hot electrons. The double sideband receiver noise temperature was measured to be approximate to 2750 K at 2.5 THz; and mixer IF bandwidths as high as 9 GHz are achieved for 0.1 mu m long devices. The local oscillator (LO) power dissipated in the HEB microbridge was in the range 20-100 nW. Further reductions in LO power and mixer noise can be potentially achieved by using A1 microbridges. The advantages and parameters of such devices are evaluated. A distributed-temperature model has been developed to properly describe the operation of the diffusion-cooled HEB mixer. The HEB mixer is a primary candidate for ground based, airborne and spaceborne heterodyne instruments at THz frequencies. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP McGrath, WR (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, M-S 168-314,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 33 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3087-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3617 BP 80 EP 88 DI 10.1117/12.347111 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Spectroscopy SC Engineering; Optics; Physics; Spectroscopy GA BN09R UT WOS:000080659300010 ER PT S AU Dougherty, DJ Guttierrez, RC Dubovitsky, S Forouhar, S AF Dougherty, DJ Guttierrez, RC Dubovitsky, S Forouhar, S BE Fallahi, M Linden, KJ Wang, SC TI Semiconductor laser linewidth measurements for space interferometry applications SO TESTING, PACKAGING, RELIABILITY, AND APPLICATIONS OF SEMICONDUCTOR LASERS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Testing, Packaging, Reliability, and Applications of Semiconductor Lasers IV CY JAN 28, 1999 CL SAN JOSE, CA SP SPIE, Defense Adv Res Projects Agcy DE DFB laser; delayed self-heterodyne interferometer; laser linewidth ID NOISE AB Narrow linewidth (<100KHz) semiconductor lasers are expected to be a key technology in NASA's stellar interferometry missions to search for planets around nearby stars. Long coherence length lasers are needed for precise (20 pm to 5 nm) measurements of the optical path difference. This work discusses results using the self-heterodyne delay technique to measure 1.3 um InP based DFB lasers. We will also address practical issues concerning detection and elimination of back reflections, choice of fiber length and resolution, and measurement of laser 1/f and current supply noise. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dougherty, DJ (reprint author), CALTECH, Jet Prop Lab, MS302-306, Pasadena, CA 91109 USA. NR 9 TC 2 Z9 2 U1 2 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3096-X J9 P SOC PHOTO-OPT INS PY 1999 VL 3626 BP 115 EP 122 DI 10.1117/12.345421 PG 8 WC Optics SC Optics GA BN06D UT WOS:000080521700013 ER PT J AU Otterman, J Atlas, R Ardizzone, J Starr, D Jusem, JC Terry, J AF Otterman, J Atlas, R Ardizzone, J Starr, D Jusem, JC Terry, J TI Relationship of late-winter temperatures in Europe to North Atlantic surface winds: A correlation analysis SO THEORETICAL AND APPLIED CLIMATOLOGY LA English DT Article ID EL-NINO AB The relationship between European surface temperature and winds over the eastern North Atlantic are investigated for the years 1988 to 1997. Daily Special Sensor Microwave Imager SSM/I observations are used to evaluate a monthly surface wind index that quantifies the influence of southwesterly flow. Our wind index and the monthly-mean surface-air temperatures in late winter and early spring over France and northern-latitude Europe are highly correlated. In February, the year-to-year increases/decreases match every year for France (correlation of 0.82 with the Index); and every year with just one exception for Europe (correlation with the Index of 0.76 for a longitudinal strip through Europe 45-50 degrees N, and 0.73 for the 50-60 degrees N strip). In March, the increases/decreases of the wind Index and of the temperatures for France also match, but the correlation with the Index is lower, 0.65. The high correlation between our Index and the large interannual fluctuations in the monthly temperature in late winter and early spring indicate that the onset of the spring conditions in Europe is significantly influenced by the wind patterns over the eastern North Atlantic. Coinciding with the fluctuations from warm-Europe/high-Index winter to the opposite conditions, we observe "seesaw" effects, fluctuations over the North Atlantic, in opposite directions in the east (25-5 degrees W), and the west (65-45 degrees W). In the low-Index years we find that: (a) the surface-air temperatures in the west are appreciably higher than in the east (but slightly lower in the high-Index year), and (b) the difference between the 500 mb meridional wind in the west and that in the east is positive and large, exceeding 10 m s(-1) (but it becomes negative and small in the high-Index years). The "seesaw" effects suggest that a positive feedback exits between these cross-Atlantic temperature differences and the surface winds. C1 NASA, Goddard Space Flight Ctr, Data Adm Off, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Gen Sci Corp, Laurel, MD 20707 USA. RP Otterman, J (reprint author), NASA, Goddard Space Flight Ctr, Data Adm Off, Code 910-3, Greenbelt, MD 20771 USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 15 TC 6 Z9 7 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-798X J9 THEOR APPL CLIMATOL JI Theor. Appl. Climatol. PY 1999 VL 64 IS 3-4 BP 201 EP 211 DI 10.1007/s007040050123 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 270FJ UT WOS:000084524500006 ER PT S AU Luttgen, G Carreno, V AF Luttgen, G Carreno, V BE Dams, D Gerth, R Leue, S Massink, M TI Analyzing mode confusion via model checking SO THEORETICAL AND PRACTICAL ASPECTS OF SPIN MODEL CHECKING SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 6th International SPIN Workshop on Practical Aspects of Model Checking CY SEP 21-24, 1999 CL TOULOUSE, FRANCE ID VERIFICATION AB Mode confusion is a serious problem in aviation safety. Today 's complex avionics systems make it difficult for pilots to maintain awareness of the actual states, or modes, of the flight deck automation. NASA explores how formal methods, especially theorem proving, can be used to discover mode confusion. The present paper investigates whether state-exploration techniques, e.g., model checking, are better able to achieve this task than theorem proving and also to compare the verification tools Mur phi, SMV and Spin for the specific application. While all tools can handle the task well, their strengths are complementary. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Assessment Technol Branch, Hampton, VA 23681 USA. RP Luttgen, G (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. NR 13 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66499-8 J9 LECT NOTES COMPUT SC PY 1999 VL 1680 BP 120 EP 135 PG 16 WC Computer Science, Theory & Methods SC Computer Science GA BP76R UT WOS:000086111400009 ER PT S AU Havelund, K AF Havelund, K BE Dams, D Gerth, R Leue, S Massink, M TI Java Pathfinder a translator from Java to Promela SO THEORETICAL AND PRACTICAL ASPECTS OF SPIN MODEL CHECKING SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Meeting Abstract CT 6th International SPIN Workshop on Practical Aspects of Model Checking CY SEP 21-24, 1999 CL TOULOUSE, FRANCE C1 NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. RP Havelund, K (reprint author), NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. NR 3 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66499-8 J9 LECT NOTES COMPUT SC PY 1999 VL 1680 BP 152 EP 152 PG 1 WC Computer Science, Theory & Methods SC Computer Science GA BP76R UT WOS:000086111400011 ER PT S AU Havelund, K Skakkebaek, JU AF Havelund, K Skakkebaek, JU BE Dams, D Gerth, R Leue, S Massink, M TI Applying model checking in Java verification SO THEORETICAL AND PRACTICAL ASPECTS OF SPIN MODEL CHECKING SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 6th International SPIN Workshop on Practical Aspects of Model Checking CY SEP 21-24, 1999 CL TOULOUSE, FRANCE AB This paper presents our experiences in applying the JAVA PATHFINDER (JPF), a recently developed JAVA. to PROMELA translator, in the search for synchronization bugs in a Chinese Chess game server application written in Java. We give an overview of JPF and the subset of JAVA that it supports and describe an initial effort to abstract and analyze the game server. Finally, we evaluate the results of the effort. C1 NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. Stanford Univ, Comp Syst Lab, Stanford, CA 94305 USA. RP Havelund, K (reprint author), NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. NR 18 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66499-8 J9 LECT NOTES COMPUT SC PY 1999 VL 1680 BP 216 EP 231 PG 16 WC Computer Science, Theory & Methods SC Computer Science GA BP76R UT WOS:000086111400017 ER PT B AU Canuto, VM AF Canuto, VM BE Gimenez, A Guinan, EF Montesinos, B TI Overshooting in stars: a new formulation SO THEORY AND TESTS OF CONVECTION IN STELLAR STRUCTURE: FIRST GRANADA WORKSHOP SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1st Granada Workshop on Theory and Tests of Convection in Stellar Structure CY SEP 30-OCT 02, 1998 CL INST ASTROFISICA ANDALUCIA, GRANADA, SPAIN SP Spanish Res Council, Natl Inst Aerospace Technol HO INST ASTROFISICA ANDALUCIA ID CONVECTION; TURBULENCE; ENVELOPES AB A major hurdle in the still unresolved overshooting (OV) problem is that we do not even agree on what it means. Stellar evolution studies define it as the "extent of chemical mixing" (del(mu) not equal 0) while the theoretical models have del(mu) = 0 and define the OV as the region where the convective flux J goes to zero. Modeling overshooting is difficult because it entails stably stratified, non-local turbulence. The model cannot be ad hoc, it must have a pedigree of credibility, versatility and manageability. We present a new formulation and derive the dynamic equations in the presence of mixing of stellar material. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-95-3 J9 ASTR SOC P PY 1999 VL 173 BP 133 EP 139 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN88U UT WOS:000083347200013 ER PT S AU Snyder, GJ Caillat, T Fleurial, JP AF Snyder, GJ Caillat, T Fleurial, JP BE Tritt, TM Kanatzidis, MG Mahan, GD Lyon, HB TI Thermoelectric properties of Cr3S4-type selenides SO THERMOELECTRIC MATERIALS 1998 - THE NEXT GENERATION MATERIALS FOR SMALL-SCALE REFRIGERATION AND POWER GENERATION APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Thermoelectric Materials 1998 - The Next Generation Materials for Small-Scale Refrigeration and Power Generation Applications CY NOV 30-DEC 03, 1998 CL BOSTON, MA SP Mat Res Soc AB Several compounds with the Cr3S4 structure type have been studied for their thermoelectric properties. All exhibit low lattice thermal conductivity of about 15 mW/cmK, independent of temperature. Many of the compounds, such as Co3Se4, Ni3Se4, Fe3Se4, Ti3Se4, FeNi2Se4 and FeCo2Se4, are metals with relatively law electrical resistivity and Seebeck coefficient. The Cr containing compounds, such as Cr3Se4, NiCr2Se4, CoCr2Se4, and FeCr2Se4, have the largest Seebeck coefficients and highest resistivity. The most promising of these materials for thermoelectric applications is FeCr2Se4. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Snyder, GJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 277-207, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 19 TC 5 Z9 5 U1 1 U2 7 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-451-3 J9 MATER RES SOC SYMP P PY 1999 VL 545 BP 333 EP 338 PG 6 WC Thermodynamics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied SC Thermodynamics; Materials Science; Physics GA BN11K UT WOS:000080751000045 ER PT S AU Fleurial, JP Borshchevsky, A Ryan, MA Phillips, WM Snyder, JG Caillat, T Kolawa, A Herman, JA Mueller, P Nicolet, M AF Fleurial, JP Borshchevsky, A Ryan, MA Phillips, WM Snyder, JG Caillat, T Kolawa, A Herman, JA Mueller, P Nicolet, M BE Tritt, TM Kanatzidis, MG Mahan, GD Lyon, HB TI Development of thick-film thermoelectric microcoolers using electrochemical deposition SO THERMOELECTRIC MATERIALS 1998 - THE NEXT GENERATION MATERIALS FOR SMALL-SCALE REFRIGERATION AND POWER GENERATION APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Thermoelectric Materials 1998 - The Next Generation Materials for Small-Scale Refrigeration and Power Generation Applications CY NOV 30-DEC 03, 1998 CL BOSTON, MA SP Mat Res Soc ID ALLOYS AB Advanced thermoelectric microdevices integrated into thermal management packages and low power, electrical source systems are of interest for a variety of space and terrestrial applications. By shrinking the size of the thermoelements, or legs, of these devices, it becomes possible to handle much higher heat fluxes, as well as operate at much lower currents and higher voltages that are more compatible with electronic components. The miniaturization of state-of-the-art thermoelectric module technology based on Bi2Te3 alloys is limited due to mechanical and manufacturing constraints for both leg dimensions (100-200 mu m thick minimum) and the number of legs (100-200 legs maximum). We are investigating the development of novel microdevices combining high thermal conductivity substrate materials such as diamond, thin film metallization and patterning technology, and electrochemical deposition of thick thermoelectric films. It is anticipated that thermoelectric microcoolers with thousands of thermocouples and capable of pumping more than 200 W/cm(2) over a 30 to 60 K temperature diffrence can be fabricated. In this paper, we report on our progress in developing an electrochemical deposition process for obtaining 10-50 mu m thick films of Bi2Te3 and its solid solutions. Results presented here indicate that good quality n-type Bi2Te3, n-type Bi2Te2.95Se0.05 and p-type Bi0.5Sb1.5Te3 thick films can be deposited by this technique. Some details about the fabrication of the miniature thermoelements are also described. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Fleurial, JP (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011 OI Snyder, G. Jeffrey/0000-0003-1414-8682 NR 19 TC 20 Z9 20 U1 1 U2 10 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-451-3 J9 MATER RES SOC SYMP P PY 1999 VL 545 BP 493 EP 500 PG 8 WC Thermodynamics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied SC Thermodynamics; Materials Science; Physics GA BN11K UT WOS:000080751000066 ER PT S AU Wilt, DM Murray, CS Fatemi, NS Weizer, V AF Wilt, DM Murray, CS Fatemi, NS Weizer, V BE Coutts, TJ Benner, JP Allman, CS TI n/p/n tunnel junction InGaAs monolithic interconnected module (MIM) SO THERMOPHOTOVOLTAIC GENERATION OF ELECTRICITY: FOURTH NREL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 4th NREL Conference on Thermophotovoltaic Generation of Electricity CY OCT 11-14, 1998 CL DENVER, CO SP Natl Renewable Engergy Lab AB The Monolithic Interconnected Module (MIM), originally introduced at the First NREL thermophotovoltaic (TPV) conference, consists of low-bandgap, indium gallium arsenide (InGaAs) photovoltaic devices, series interconnected on a common semi-insulating indium phosphide (InP) substrate. An infrared reflector is deposited on the back surface of the substrate to reflect photons, which were not absorbed in the first pass through the structure. The single largest optical loss in the current device occurs in the heavily doped p-type emitter. A new MIM design (pat. pend.) has been developed which flips the polarity of the conventional MIM cell (i.e.. n/p rather than pin), eliminating the need for the high conductivity p-type emitter. The p-type base of the cell is connected to the n-tppe lateral conduction layer through a thin InGaAs tunnel junction. 0.58 eV and 0.74 eV InGaAs devices have demonstrated reflectances above 90% for wavelengths beyond the bandgap (> 95% for unprocessed structures). Electrical measurements indicate minimal voltage drops across the tunnel junction (< 3 mV/junction under 1200K-blackbody illumination) and fill factors that are above 70% at current densities (J(sc)) above 8 A/cm(2) for the 0.74eV devices. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Wilt, DM (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-828-2 J9 AIP CONF PROC PY 1999 VL 460 BP 152 EP 160 PG 9 WC Energy & Fuels; Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Condensed Matter SC Energy & Fuels; Engineering; Optics; Physics GA BM77N UT WOS:000079730800015 ER PT S AU Good, BS Chubb, DA AF Good, BS Chubb, DA BE Coutts, TJ Benner, JP Allman, CS TI Temperature gradient effects in an erbium aluminum garnet selective emitter SO THERMOPHOTOVOLTAIC GENERATION OF ELECTRICITY: FOURTH NREL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 4th NREL Conference on Thermophotovoltaic Generation of Electricity CY OCT 11-14, 1998 CL DENVER, CO SP Natl Renewable Engergy Lab AB Spectral control through the use of selective emitters is an important means of improving the efficiency of thermophotovoltaic (TPV) systems. The thin-film selective emitters developed in our laboratory offer a number of potential advantages for use in such systems. It has long been realized, however, that there may exist relatively large temperature gradients across the thickness of these emitters in operation, and that such gradients are likely to have a detrimental impact on emitter performance. Previous efforts at modeling TPV emitter or system performance have either ignored thermal gradient effects or assumed the temperature profile to be linear (1-5). A detailed investigation of the temperature profile and subsequent effects on emitter performance has not yet been given. In this paper, we present results of a detailed theoretical and computational study of the effects of thermal gradients, along with some other film parameters, on the performance of an erbium aluminum garnet (Er3Al5O12) selective emitter. Equations for the internal energy flux within the emitter are developed, under the assumption that heat transfer occurs via conduction and radiation. One face of the emitter is assumed to remain at fixed temperature, as would be the case if a thin emitter were in contact with a massive heat bath. The other face is assumed to experience either "vacuum interface" conditions, where heat transfer from the surface occurs via radiation only or "lossy" conditions, where additional losses via conduction and convection are included. The temperature profile across the emitter thickness is computed by requiring that energy be conserved everywhere. We investigate the effects of the thermal gradient on the useful output power and emitter conversion efficiency. We also consider the sensitivity of the temperature gradient to the film and substrate physical properties. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Good, BS (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 302-1, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-828-2 J9 AIP CONF PROC PY 1999 VL 460 BP 214 EP 223 PG 10 WC Energy & Fuels; Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Condensed Matter SC Energy & Fuels; Engineering; Optics; Physics GA BM77N UT WOS:000079730800020 ER PT S AU Chubb, DL AF Chubb, DL BE Coutts, TJ Benner, JP Allman, CS TI Emittance theory for cylindrical fiber selective emitter SO THERMOPHOTOVOLTAIC GENERATION OF ELECTRICITY: FOURTH NREL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 4th NREL Conference on Thermophotovoltaic Generation of Electricity CY OCT 11-14, 1998 CL DENVER, CO SP Natl Renewable Engergy Lab AB A fibrous rare earth selective emitter is approximated as an infinitely long cylinder. The spectral emittance, epsilon(lambda), is obtained by solving the radiative transfer equations with appropriate boundary conditions and uniform temperature. For optical depths, K-R = alpha(lambda)R, where alpha(lambda) is the extinction coefficient and R is the cylinder radius, greater than 1 the spectral emittance is nearly at its maximum value. There is an optimum cylinder radius, R-opt, for maximum emitter; efficiency, eta(E). Values for R-opt are strongly dependent on the number of emission bands of the material. The optimum radius decreases slowly with increasing emitter temperature, while the maximum efficiency and useful radiated power increase rapidly with increasing temperature. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chubb, DL (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-828-2 J9 AIP CONF PROC PY 1999 VL 460 BP 463 EP 471 PG 9 WC Energy & Fuels; Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Condensed Matter SC Energy & Fuels; Engineering; Optics; Physics GA BM77N UT WOS:000079730800044 ER PT S AU Plotnikov, YA Winfree, WP AF Plotnikov, YA Winfree, WP BE LeMieux, DH Snell, JR TI Visualization of subsurface defects in composites using a focal plane array infrared camera SO THERMOSENSE XXI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Thermosense XXI CY APR 06-08, 1999 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE infrared; thermography; image analysis; focal plane array detector; nondestructive evaluations ID THERMOGRAPHY AB A technique for enhanced defect visualization in composites via transient thermography is presented in this paper. The effort targets automated defect map construction for multiple defects located in the observed area. Experimental data were collected on composite panels of different thickness with square inclusions and flat bottom holes of different depth and orientation. The time evolution of the thermal response and spatial thermal profiles are analyzed. The pattern generated by carbon fibers and the vignetting effect of the focal plane array camera make defect visualization difficult. An improvement of the defect visibility is made by the pulse phase technique and the spatial background treatment. The relationship between a size of a defect and its reconstructed image is analyzed as well. The image processing technique for noise reduction is discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Plotnikov, YA (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 6 TC 8 Z9 8 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3174-5 J9 P SOC PHOTO-OPT INS PY 1999 VL 3700 BP 26 EP 31 DI 10.1117/12.342301 PG 6 WC Engineering, Mechanical; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BM93Z UT WOS:000080193300005 ER PT S AU Fischer, DG Ovryn, B AF Fischer, DG Ovryn, B BE Cabib, D Cogswell, CJ Conchello, JA Lerner, JM Wilson, T TI Calibrating interference microscopes by measuring the equilibrium shape and contact angle of fluid drops SO THREE-DIMENSIONAL AND MULTIDIMENSIONAL MICROSCOPY: IMAGE ACQUISITION AND PROCESSING VI, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on 3-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing VI CY JAN 24-25, 1999 CL SAN JOSE, CA SP SPIE, Int Biomed Opt Soc ID NUMERICAL APERTURE AB Calibration of the axial response of interference microscopes has received considerable attention in the past two decades. In addition to systematic errors which could be caused by components in the microscope or measurement technique, a numerical correction factor associated with imaging at high apertures must be determined. Unfortunately, the cost of reference height standards increases sharply with their spatial homogeneity and calibration accuracy and these standards may be easily contaminated and therefore require sophisticated cleaning and re-calibration. To address these problems, we have investigated the interferometric measurement of the equilibrium shape of static fluid drops on coated substrates. For drops with small Bond number (the Bond number is a ratio of gravitational to capillary forces), the surface of the drop forms a spherical cap. It appears that nature forms a highly smooth, curved surface. By varying the surface energy, it is possible to obtain a wide range of static contact angles. For example, silicone oil (polydimethylsiloxane (PDMS)) on glass forms a contact angle of about 5 degrees, while it forms an angle of 38 degrees on Teflon and 68 degrees on a fluorinated silicon surface. We have measured contact angles as large as 68 degrees for PDMS on a single crystal silicon wafer with a 50 x/0.8 NA objective using a custom-made phase-shifted, laser feedback microscope. The method for preparing these static drops is simple and we envision that microscopists will be able to prepare easily disposable calibration standards in their laboratories. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Fischer, DG (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, MS 110-3,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 13 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3075-7 J9 P SOC PHOTO-OPT INS PY 1999 VL 3605 BP 120 EP 128 DI 10.1117/12.347560 PG 9 WC Microscopy; Optics SC Microscopy; Optics GA BN09P UT WOS:000080657900015 ER PT S AU McDonald, FB Fujii, Z Ferrando, P Heber, B Raviart, A Kunow, H Muller-Mellin, R Wibberenz, G McGuire, R Paizis, C AF McDonald, FB Fujii, Z Ferrando, P Heber, B Raviart, A Kunow, H Muller-Mellin, R Wibberenz, G McGuire, R Paizis, C BE Potgieter, MS TI Studies of the cosmic ray radial and latitudinal intensity gradients over the cycle 22 solar minimum period SO TRANSPORT OF GALACTIC AND ANOMALOUS COSMIC RAYS IN THE HELIOSPHERE: OBSERVATIONS, SIMULATIONS AND THEORY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 6 Symposium of COSPAR Scientific Commission D on the Transport of Galactic and Anomalous Cosmic Rays in the Heliosphere, 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, Inst Space & Astronaut Sci ID OUTER HELIOSPHERE; DRIFT; MODULATION; TRANSPORT; MODEL; SOUTH; POLE AB The spatial intensity gradients of galactic and anomalous cosmic ray helium are studied over the 1993.0-1998.0 time period using data from cosmic ray experiments on IMP 8, Ulysses, Voyagers 1 and 2 and Pioneer 10. When combined with the results of previous studies, a remarkable ordering of the radial gradients for the galactic component is found over 2 complete solar cycles and 3 successive solar minima. The latitudinal gradients for the cycle 22 solar minimum period are zero or small and positive in the inner and outer heliosphere in contrast to the much larger negative latitudinal gradients observed in the outer heliosphere in 1987 over the cycle 21 solar minimum. The changes in the intensity gradients over the 3 solar minimum periods require that at these times drift effects play an important role in the transport of cosmic rays in the heliosphere and provide further evidence for the existence of a 22-year solar modulation cycle. The Ulysses data plays a pivotal role in understanding the spatial gradients over the cycle 22 recovery and solar minimum period. (C) 1999 COSPAR. Published by Elsevier Science Ltd. C1 Univ Maryland, IPST, College Pk, MD 20742 USA. CE Saclay, Serv Astrophys, CEA DSM DAPNIA, Gif Sur Yvette, France. Nagoya Univ, Solar Terr Environm Lab, Chikusa Ku, Nagoya, Aichi, Japan. Univ Kiel, Inst Exp & Angew Phy, D-24098 Kiel, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Milan, Ist Fis Cosm, Milan, Italy. RP McDonald, FB (reprint author), Univ Maryland, IPST, College Pk, MD 20742 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1999 VL 23 IS 3 BP 453 EP 458 DI 10.1016/S0273-1177(99)00104-0 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BN23U UT WOS:000081205800006 ER PT S AU Prestage, JD Tjoelker, RL Maleki, L AF Prestage, JD Tjoelker, RL Maleki, L BE Dubin, DHE Schneider, D TI Hg(+) frequency standards SO TRAPPED CHARGED PARTICLES AND FUNDAMENTALS PHYSICS SE AIP Conference Proceedings LA English DT Proceedings Paper CT International Conference on Trapped Charged Particles and Fundamental Physics CY AUG 31-SEP 04, 1998 CL PACIFIC GROVE, CA SP Lawrence Livermore Natl Lab ID FINE-STRUCTURE CONSTANT AB In this paper we review the development of Hg(+) microwave frequency standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term frequency stability of 3x10(-14)/root tau when a cryogenic oscillator of stability 2-3x10(-15) was used as the local oscillator. The trapped ion frequency standard employs a (202)Hg discharge lamp to optically pump the trapped (199)Hg(+) clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg+ ion trap based frequency standard with an extended linear ion trap (LITE) architecture which separates the optical state selection region from the clock resonance region. This separation allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At similar to 10(-12), the 2(nd) order Doppler shift for trapped mercury ion frequency standards is one of the largest frequency offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(-14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time variation of the fine structure constant, alpha = e(2)/2 pi hc, at the level of 10(-20)/year as predicted in some Grand Unified String Theories. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91104 USA. RP Prestage, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Bldg 298, Pasadena, CA 91104 USA. NR 12 TC 2 Z9 2 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-776-6 J9 AIP CONF PROC PY 1999 VL 457 BP 357 EP 364 PG 8 WC Physics, Fluids & Plasmas; Physics, Multidisciplinary; Physics, Nuclear; Physics, Particles & Fields; Spectroscopy SC Physics; Spectroscopy GA BM77Q UT WOS:000079731200050 ER PT B AU Pain, B Yang, G Olson, B Shaw, T Ortiz, M Heynssens, J Wrigley, C Ho, C AF Pain, B Yang, G Olson, B Shaw, T Ortiz, M Heynssens, J Wrigley, C Ho, C GP IEEE IEEE TI A low-power digital camera-on-a-chip implemented in CMOS active pixel approach SO TWELFTH INTERNATIONAL CONFERENCE ON VLSI DESIGN, PROCEEDINGS LA English DT Proceedings Paper CT 12th International Conference on VLSI Design CY JAN 07-10, 1999 CL GOA, INDIA SP VLSI Soc India, Dept Electron, Govt India, IEEE Circuits & Syst Soc, IEEE, ACM SIGDA AB The advent of high performance imaging in CMOS technology using active pixel sensors has enabled ultra-low power, miniature, integrated single-chip camera systems. We report the first fully digital, programmable, 5-wire, large format (512x512) digital-camera-on-a-chip that integrates the imager array control logic, ADC, and bias generation on the same chip. The VLSI chip runs off a single (3.3 V) power supply consumes only 8 mW at video rates, is capable of electronic panning, and produces high quality images with 78 dB dynamic range. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0013-7 PY 1999 BP 26 EP 31 DI 10.1109/ICVD.1999.745119 PG 6 WC Computer Science, Hardware & Architecture; Engineering, Manufacturing; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BM29H UT WOS:000078294500004 ER PT S AU Thompson, WT AF Thompson, WT BE Fineschi, S Woodgate, BE Kimble, RA TI UV detectors aboard SOHO SO ULTRAVIOLET AND X-RAY DETECTION, SPECTROSCOPY, AND POLARIMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet and X-Ray Detection, Spectroscopy, and Polarimetry III CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE UV detectors; space missions ID SOLAR; SPECTROMETER; SUMER; CELIAS/SEM; TELESCOPE; MISSION; EIT AB A wide variety of ultraviolet detectors are used aboard the Solar and Heliospheric Observatory (SOHO) spacecraft. The ultraviolet instrument package aboard SOHO includes one full disk EUV flux monitor (SEM: 30.4 nm), one full sky mapper (SWAN: 121.6 nm), one full-Sun imager (EIT: 17.1-30.4 nm), and three spectrometers (CDS: 15.1-78.5 nm; SUMER: 66.0-161.0 nm; UVCS: 93.7-136.1 nm). All wavelengths are first order. In total, there are fifteen UV detectors aboard SOHO with six distinctly different designs. These range from photodiodes, through backside-thin CCDs, to two-dimensional microchannel-plate detectors. Some instruments measure an analog signal (such as the charge deposited in a CCD well), while others measure single photon events. The intense brightness of the Sun imposes unique challenges on these astronomical detectors. After almost three years of continuous observation in space, a large body of data has been gathered on their performance. How well each detector system has performed over this period is examined in turn. C1 NASA, Goddard Space Flight Ctr, SM&A Corp, Space Sci & Engn, Greenbelt, MD 20771 USA. RP Thompson, WT (reprint author), NASA, Goddard Space Flight Ctr, SM&A Corp, Space Sci & Engn, Code 682, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012; Thompson, William/D-7376-2012 NR 13 TC 14 Z9 14 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3250-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3764 BP 196 EP 208 DI 10.1117/12.371084 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BP33T UT WOS:000084756600020 ER PT S AU Kimble, RA Abraham, J Argabright, VS Bohlin, RC Bybee, R Culver, E Danks, AC Franka, S Gilliland, RL Joseph, CL Kaiser, ME Lindler, DJ Long, CA Shaw, RA Styonavich, M Timothy, JG Van Houten, CN Woodgate, BE AF Kimble, RA Abraham, J Argabright, VS Bohlin, RC Bybee, R Culver, E Danks, AC Franka, S Gilliland, RL Joseph, CL Kaiser, ME Lindler, DJ Long, CA Shaw, RA Styonavich, M Timothy, JG Van Houten, CN Woodgate, BE BE Fineschi, S Woodgate, BE Kimble, RA TI In-flight performance of the MAMA detectors on the space telescope imaging spectrograph SO ULTRAVIOLET AND X-RAY DETECTION, SPECTROSCOPY, AND POLARIMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet and X-Ray Detection, Spectroscopy, and Polarimetry III CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE detectors; ultraviolet; microchannel plate; MAMA; space instrumentation; spectroscopy; HST ID ARRAY DETECTOR; STIS; STABILITY AB The Space Telescope Imaging Spectrograph (STIS) is a versatile HST instrument covering the 115-1000 nm wavelength range in a variety of spectroscopic and imaging modes. Coverage of the ultraviolet range (115 - 310 nm) is provided by two Multi-Anode Microchannel Array (MAMA) detectors built by Ball Aerospace. The FUV MAMA covers the 115-170 nm range using an opaque CsI photocathode on the microchannel plate; the NUV MAMA covers the 165-310 nm range using a semi-transparent Cs2Te photocathode on the detector window. Both MAMAs utilize a 1024 x 1024 anode format, but detected photon events are positioned to half the spacing of the anode lines, leading to a 2048 x 2048 format for the final readout. The active area of each detector is 25.6 x 25.6 mm. Since the installation of STIS onto the Hubble Space Telescope (HST) in February 1997, the MAMAs have carried out a varied program of astronomical observing and in-flight calibration. The detectors have performed extremely well. In this report, we briefly describe the design of the STIS MAMA detectors, provide illustrative examples of their scientific use on HST, and summarize their technical performance in orbit, in such areas as sensitivity, resolution, flat-field uniformity and stability, signal-to-noise capability, dynamic range, and background. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kimble, RA (reprint author), Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 24 TC 6 Z9 6 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3250-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3764 BP 209 EP 225 DI 10.1117/12.371085 PG 17 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BP33T UT WOS:000084756600021 ER PT S AU Norton, T Morrissey, P Haas, P Payne, L Carbone, J Kimble, R AF Norton, T Morrissey, P Haas, P Payne, L Carbone, J Kimble, R BE Fineschi, S Woodgate, BE Kimble, RA TI Photon counting intensified random-access charge injection device SO ULTRAVIOLET AND X-RAY DETECTION, SPECTROSCOPY, AND POLARIMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet and X-Ray Detection, Spectroscopy, and Polarimetry III CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE CID; detector; intensifier; microchannel plates; ultraviolet AB At NASA GSFC we are developing a high resolution solar-blind photon counting detector system for UV space based astronomy. The detector comprises a high gain MCP intensifier fibre-optically coupled to a charge injection device (CID). The detector system utilizes an FPGA based centroiding system to locate the center of photon events from the intensifier to high accuracy. The photon event addresses are passed via a PCI interface with a GPS derived time stamp inserted per frame to an integrating memory. Here we present imaging performance data which show resolution of MGP tube pore structure at an MCP pore diameter of 8 mu m. This data validates the ICID concept for intensified photon counting readout. We also discuss correction techniques used in the removal of fixed pattern noise effects inherent in the centroiding algorithms used and present data which shows the local dynamic range of the device. Progress towards development of a true random access CID (RACID 810) is also discussed and astronomical data taken with the ICID detector system demonstrating the photon event time-tagging mode of the system is also presented. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Norton, T (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 7 TC 2 Z9 2 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3250-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3764 BP 234 EP 245 DI 10.1117/12.371087 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BP33T UT WOS:000084756600023 ER PT S AU Huang, TZC Mott, DB La, A AF Huang, TZC Mott, DB La, A BE Fineschi, S Woodgate, BE Kimble, RA TI Development of 256x256 GaN ultraviolet imaging arrays SO ULTRAVIOLET AND X-RAY DETECTION, SPECTROSCOPY, AND POLARIMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet and X-Ray Detection, Spectroscopy, and Polarimetry III CY JUL 19-20, 1999 CL DENVER, CO SP SPIE DE GaN; photoconductor; ultraviolet detector; array; MOCVD; UV camera ID PHOTOCONDUCTORS AB We have successfully developed a prototype 256x256 photoconductive GaN ultraviolet (UV) imaging army. The array, with its pixels (30x30 mu m(2)) indium bump bonded to a Lockheed Martin Fairchild Systems LT9601 readout integrated circuit, is highly sensitive to ultraviolet light below 365 nm with a sharp reduction in response to visible and infrared light. The array was installed into a custom designed UV camera utilizing a Nikon UV lens with all the off-chip electronics interfaced to an automatic computer controlled system. To the best of our knowledge, this is the first reported UV array camera based on the nitride materials. C1 NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 20771 USA. RP Huang, TZC (reprint author), NASA, Goddard Space Flight Ctr, Detector Syst Branch, Code 553, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 6 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3250-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3764 BP 254 EP 260 DI 10.1117/12.371089 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BP33T UT WOS:000084756600025 ER PT S AU Nuth, JA Lowrance, JL Renda, G Carruthers, GR AF Nuth, JA Lowrance, JL Renda, G Carruthers, GR BE Carruthers, GR Dymond, KF TI A fast UV slitless spectrometer for meteor research SO ULTRAVIOLET ATMOSPHERIC AND SPACE REMOTE SENSING: METHODS AND INSTRUMENTATION II SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Ultraviolet Atmospheric and Space Remote Sensing - Methods and Instrumentation II CY JUL 22, 1999 CL DENVER, CO SP SPIE, Remote Sensing Soc AB Meteoric material of asteroidal and cometary origin enters Earth's atmosphere continuously, but it has been difficult to determine the relative abundances and total incoming fluxes of these two major types from studies of recovered meteorites and ground-based observations of incoming meteors. This is largely due to both the different physical properties and chemical compositions of meteoroids, of types ranging from nearly pure iron (probably of asteroidal origin) to the carbonaceous chondrites (possibly of cometary origin). Observations of meteors in the ultraviolet spectral range, from above the atmosphere, can provide important new information on the chemical abundances in meteors which is not available from visible or infrared ground-based measurements. In particular, the UV spectral range is especially important for measurements of H, C, O, N, Mg, Al, and Si, which complement longer-wavelength measurements of Ca, Fe, and Na. We have designed a wide-field, objective grating spectrograph based on a Schmidt optical system, similar to one flown in sounding rocket investigations by the Naval Research Laboratory. The instrument covers a field of view 10 degrees in diameter, has a spectral range of 130-300 nanometers, and utilizes a solar blind image intensifier tube coupled to a CCD array camera. The instrument could be flown as a Shuttle Hitchhiker payload, in a Spartan mission, or (eventually) as a Space Station attached payload. Another possible application of the instrument would be to observe any UV emission from lightning "sprites", which would be prominent if these extend to high enough altitudes to be above a significant portion of the ozone layer. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Nuth, JA (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Nuth, Joseph/E-7085-2012 NR 18 TC 4 Z9 4 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3304-7 J9 PROC SPIE PY 1999 VL 3818 BP 108 EP 124 DI 10.1117/12.364147 PG 17 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing; Optics SC Engineering; Instruments & Instrumentation; Remote Sensing; Optics GA BN99K UT WOS:000083801800013 ER PT B AU Hasan, H Chakrabarti, S Kimble, R Lillie, C Mucklow, G Shao, M Woodruff, R AF Hasan, H Chakrabarti, S Kimble, R Lillie, C Mucklow, G Shao, M Woodruff, R BE Morse, JA Shull, JM Kinney, AL TI Technology panel discussion SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific AB The Technology Panel highlighted three priority areas for technology development in the next decade: 1) Detectors; 2) Lightweight mirrors; 3) Mirror coatings. Other issues are: funding sources, interferometers, imaging spectrometers, large field-of-view telescope technology, launch vehicle capability, strategies for lowering cost, tradeoffs of taking risks and flying untested, cutting-edge technology, and areas where universities could provide specialized expertise. C1 NASA, Discipline Ultraviolet Visible & Gravitat Astroph, Washington, DC 20546 USA. RP Hasan, H (reprint author), NASA, Discipline Ultraviolet Visible & Gravitat Astroph, Code SR,Headquarters, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 37 EP 39 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700006 ER PT B AU Grady, CA Sitko, ML Woodgate, B AF Grady, CA Sitko, ML Woodgate, B BE Morse, JA Shull, JM Kinney, AL TI The prospects for detecting star-grazing planetesimals around young, solar-mass stars SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific ID BETA-PICTORIS; CIRCUMSTELLAR DISKS; SYSTEMS; DUST; GAS AB UV spectroscopic studies of star-grazing material associated with young 2-8 M. stars has provided insight into the nature of the planetesimals and potentially the presence of larger bodies in these disks. We review the prospects for extending these studies to young Suns with HST using current and planned instrumentation, and discuss what could be achieved with a larger telescope and state-of-the-art instrumentation. C1 NASA GSFC, NOAO STIS, Greenbelt, MD 20771 USA. RP Grady, CA (reprint author), NASA GSFC, NOAO STIS, Greenbelt, MD 20771 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 159 EP 163 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700021 ER PT B AU Woodgate, BE Kimble, RA AF Woodgate, BE Kimble, RA BE Morse, JA Shull, JM Kinney, AL TI Space Telescope Imaging Spectrograph (STIS) capabilities and future detector prospects SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific AB This paper is in three sections: 1. An overview of STIS performance in tabular form. 2. Examples of on-orbit data to illustrate the qualitative types of capability to act as a reference for future instruments. 3. A description of the STIS detectors as a reference for future technology improvements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Woodgate, BE (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 10 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 166 EP 175 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700022 ER PT B AU Gardner, JP AF Gardner, JP BE Morse, JA Shull, JM Kinney, AL TI The science goals of the Next Generation Space Telescope SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific AB The Next Generation Space Telescope will be an 8 meter telescope optimized for the near-infrared wavelength region, with stretch goals of 0.6 to 30 microns. It is scheduled for launch in approximately 2007. The science goals include: 1. Detecting and studying the first generation of stars in the Universe. 2. Detecting high redshift supernovae. 3. Studying the structure and dynamics of galaxies during all epochs of star formation. 4. Studying stellar populations in our galaxy and nearby galaxies. 5. Studying star forming regions and proto-planetary disks. 6. Studying Kuiper belt objects. 7. Directly imaging planets around nearby stars. I report on recent progress made by the NGST Ad-Hoc Science Working Group in defining the Design Reference Mission, a set of science goals meant to influence the design of the telescope. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gardner, JP (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 207 EP 214 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700027 ER PT B AU Unwin, SC Turyshev, SG AF Unwin, SC Turyshev, SG BE Morse, JA Shull, JM Kinney, AL TI The Space Interferometry Mission SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific ID SIM AB The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. SIM will extend the reach of precision astrometry to cover the entire Galaxy, and will address a diverse set of topics in Galactic astronomy. It will also serve as a technology pathfinder for future astrophysics missions. The SIM architecture uses a 10-m Michelson interferometer in Earth-trailing solar orbit to provide 4 microarcsecond (mu as) precision absolute position measurements of stars down to 20 magnitude. The corresponding parallax accuracy allows distance measurements to better than 10% accuracy at 25 kpc. SIM will allow us to measure absolute luminosities of many stellar constituents of the Galaxy with unparalleled accuracy. Calibration of indicators in the cosmic distance scale is an obvious application. SIM will achieve a proper motion accuracy of about 2 mu as yr(-1) during its 5-year lifetime, equivalent to 10 m s(-1) at 1 kpc. This sensitivity will allow SIM to perform an astrometric (reflex motion) search for low-mass planets around a large sample of nearby stars. Combining distances and proper motions measured using SIM with ground-based radial-velocity data provides a powerful tool for stellar dynamics. Using samples of stars in the Galactic disk and the halo as tracers, SIM will address a variety of questions relating to the formation and dynamics of the Galaxy. In addition to precision astrometry, SIM will produce images with a resolution of 10 milliarcsec, equivalent to a diffraction-limited optical aperture of 10 meters. It will also demonstrate interferometric nulling with suppression of the on-axis starlight to a level of 10(-4). In this paper we present selected topics from the SIM science program focusing on some specific astronomical questions to be addressed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 215 EP 222 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700028 ER PT B AU Deutsch, M McLaughlin, W Nichols, J AF Deutsch, M McLaughlin, W Nichols, J BE Morse, JA Shull, JM Kinney, AL TI New approach to concept feasibility and design studies for astrophysics missions SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific AB Recent automated and advanced techniques developed at JPL have created a streamlined and fast-track approach to initial mission conceptualization and system architecture design, answering the need for rapid turnaround of trade studies for potential proposers, as well as mission and instrument study groups. JPL has assembled a team of multidisciplinary experts with corporate knowledge of space mission and instrument development. The advanced Concept Design Team, known as Team X, provides interactive design trades including cost as a design parameter, and advanced visualization for pre-Phase A Studies. The proposer and Team X collaborate closely in developing scenarios, and Team X responds with a detailed integrated mission/instrument design and development plan within 1-3 weeks. Iteration of the plan is on a similar rapid turnaround basis. JPL has experience planning more than 250 missions, including pointed and survey astrophysics missions such as GALEX, SIM, IRAS, SIRTF, and WIRE. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deutsch, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 340 EP 344 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700044 ER PT B AU Kimble, RA Norton, TJ Morrissey, PF AF Kimble, RA Norton, TJ Morrissey, PF BE Morse, JA Shull, JM Kinney, AL TI A photon-counting intensified CID detector for space astronomy SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific AB We describe a novel solar-blind, high-resolution, photon-counting detector for applications in space ultraviolet astronomy, currently under development at the Goddard Space Flight Center. Our concept is to utilize a charge injection device (CID) as the readout stage behind a microchannel plate (MCP) intensifier. This detector will take advantage of the addressable readout capability afforded by the CID to provide high local frame rates around bright features in an image, thereby ameliorating the principal disadvantage of analogous intensified CCD detectors. We report here on the progress of our development work, including the demonstration of MCP-pore-limited resolution using a commercial CID camera and a GSFC-developed event centroider. We also describe a custom "true random access" CID currently in fabrication in collaboration with CIDTEC, Inc. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Kimble, RA (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 5 TC 3 Z9 3 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 392 EP 396 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700049 ER PT B AU Keski-Kuha, RAM Larruquert, JI Gum, JS Fleetwood, CM AF Keski-Kuha, RAM Larruquert, JI Gum, JS Fleetwood, CM BE Morse, JA Shull, JM Kinney, AL TI Optical coatings and materials for ultraviolet space applications SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific ID EXTREME-ULTRAVIOLET; SILICON-CARBIDE; VACUUM-ULTRAVIOLET; TELESCOPE MIRROR; EUV REFLECTANCE; PERFORMANCE; SUMER; DEGRADATION AB Advances in optical coatings and materials technology have made possible the development of instruments with substantially improved efficiency and consideration of more complex optical designs in the UV. We review the performance of a range of candidate broadband optical coatings and materials for normal incidence applications in the ultraviolet spectral region. Some strengths and problem areas for their use in space are addressed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Keski-Kuha, RAM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 27 TC 16 Z9 16 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 406 EP 419 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700051 ER PT B AU Boucarut, R Bush, F Content, D Leviton, D Madison, T Miner, L Norton, T Petrone, P Puc, B Saha, T Standley, C AF Boucarut, R Bush, F Content, D Leviton, D Madison, T Miner, L Norton, T Petrone, P Puc, B Saha, T Standley, C BE Morse, JA Shull, JM Kinney, AL TI Ultraviolet-optical instrument development in the diffraction grating evaluation facility SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific ID HUBBLE-SPACE-TELESCOPE; HST ADVANCED CAMERA; SURVEYS ACS; PERFORMANCE; FILTERS; VACUUM AB Since its initial use on the SOHO spectrographic instruments, the Diffraction Grating Evaluation Facility at NASA Goddard Space Flight Center has been used to develop numerous ultraviolet and visible instruments for space science. Several notable techniques and metrology capabilities have been introduced. We review the facility and its capabilities, give examples of unique applications, and present plans for future applications. C1 NASA, Opt Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Boucarut, R (reprint author), NASA, Opt Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 24 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 446 EP 452 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700055 ER PT B AU Content, D Leviton, D Boucarut, R Keski-Kuha, R Madison, T Miner, L Norton, T Petrone, P Quijada, M AF Content, D Leviton, D Boucarut, R Keski-Kuha, R Madison, T Miner, L Norton, T Petrone, P Quijada, M BE Morse, JA Shull, JM Kinney, AL TI FUV-NIR filter metrology in the GSFC optics branch SO ULTRAVIOLET-OPTICAL SPACE ASTRONOMY BEYOND HST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Ultraviolet-Optical Space Astronomy Beyond HST CY AUG 05-07, 1998 CL BOULDER, CO SP Astron Soc Pacific ID HUBBLE-SPACE-TELESCOPE; HST ADVANCED CAMERA; SURVEYS ACS AB We have developed filter metrology techniques and capabilities that allow significantly better calibration of filter based instruments, both passive (including HST/ACS) and active (such as lidars and altimeters) than had been previously available. We review the capabilities and give examples of filters tested for both space and earth science in the 115-1100 nm spectral range. Examples include the mapping of transmission for large-format filters for HST/ACS, deep out-of-band rejection measurements from FUV-NIR, and verification of very narrowband filters for lidar work. C1 NASA, Opt Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Content, D (reprint author), NASA, Opt Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-85-6 J9 ASTR SOC P PY 1999 VL 164 BP 453 EP 458 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN32E UT WOS:000081619700056 ER PT S AU Mather, JC Smith, EP AF Mather, JC Smith, EP BE Cox, P Kessler, MF TI Next Generation Space Telescope and future missions SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE ISO; infrared astronomy; NGST; interferometers AB The infrared band (1 mu m-1 mm), largely unobservable from the ground, is one of the outstanding frontiers of space astronomy. Rapid progress in detector technology, lightweight cold mirrors, deep space missions, and new concepts in instrumentation continues to open this frontier. Planned missions include the SIRTF, SOFIA, NGST, FIRST, Planck, and ASTRO-F. Proposed missions include the Japanese H II/L2 mission, several forms of imaging interferometers to search for planets and resolve detailed structures, and a far IR interferometer called SPECS. We review the scientific objectives and technical progress that enable each of these missions, and discuss the ultimate limits that might be achieved. The prospect of achieving HST-like sensitivity and angular resolution over the entire range of infrared wavelengths is real and scientifically exciting. The technical innovation required is difficult but not impossible. Continuing revolutions in manufacturing and engineering processes can enable scientific breakthroughs of immense importance. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mather, JC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SP PUBL PY 1999 VL 427 BP 103 EP 110 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900018 ER PT S AU Werner, MW AF Werner, MW BE Cox, P Kessler, MF TI Scientific opportunities with SIRTF SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE SIRTF; infrared astronomy; legacy science ID TELESCOPE FACILITY SIRTF; SPACE AB This paper summarizes the scientific opportunities made available by SIRTF - the Space Infrared Telescope Facility. SIRTF will be a cryogenically-cooled space telescope instrumented with large-format, state of the art monolithic infrared detector arrays. SIRTF will complete NASA's family of Great Observatories and also serve as the first major scientific and technical step in the Origins program. It will be launched in 2001, carrying a complement of imaging and spectroscopic instrumentation, for a mission approximate to 5 yr in duration. More than 75% of the observing time on SIRTF will be available to the general scientific community. The first opportunity for the general community to propose for observing time on SIRTF will come with the first call for Legacy Science proposals, to be released in July, 2000. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Werner, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SP PUBL PY 1999 VL 427 BP 119 EP 122 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900021 ER PT S AU Dwek, E Arendt, RG Moseley, HS AF Dwek, E Arendt, RG Moseley, HS BE Cox, P Kessler, MF TI Newly-synthesized elements and pristine dust in the Cas A supernova remnant as observed by ISO SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE supernova remnants; dust; nucleosynthesis ID CASSIOPEIA-A SUPERNOVA; INFRARED-EMISSION; GAS AB Spectroscopic observations at 2.4 - 45 mu m of the young supernova remnant Cas A with the Infrared Space Observatory (ISO) Short wavelength Spectrometer (SWS) reveal strong emission lines of O, Ne, Si, S, and Ar. These lines are observed at high velocities (several 10(3) km s(-1)), and are therefore associated with the supernova ejecta known as the fast-moving knots (FMKs). Continuum emission from dust is also seen in the Cas A spectrum. The continuum strength is spatially well correlated with the O and Ar line strengths, indicating that the dust, emission also arises from the FMKs. The dust continuum has an emission feature at similar to 22 mu m which cannot be fit by typical astronomical silicates, but can be fit with a particular class of silicate minerals. This suggests that the dust in Cas A is silicate material that has freshly condensed from the Cas A ejecta into a mineral form that is uncharacteristic of typical ISM dust grains. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dwek, E (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Moseley, Harvey/D-5069-2012 NR 19 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SP PUBL PY 1999 VL 427 BP 237 EP 240 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900045 ER PT S AU Stapelfeldt, K Moneti, A AF Stapelfeldt, K Moneti, A BE Cox, P Kessler, MF TI The spectral energy distribution of HH 30 measured with ISO SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE accretion disks; young stars ID STARS AB Herbig-Haro 30 is a prototype young stellar object (YSO) accretion disk system located in the nearby Taurus L1551 molecular cloud. Hubble Space Telescope images have shown that HH 30 appears as a nearly edge-on, optically thick circumstellar disk extending perpendicular to highly collimated bipolar jets. As the first YSO disk to have its vertical structure clearly resolved, HH 30 presents a unique opportunity to combine our understanding of a disk's geometry and its spectral energy distribution (SED). ISO photometry using CAM and PHT have been obtained over the wavelength range of 5-90 mu m, filling important gaps in the observed SED of this object. We find that the SED is double-peaked, with one peak at 2 mm and a second somewhere beyond 60 mm. A weak silicate absorption feature may be present. Given that HH 30 appears entirely as scattered light in images made at 2 mu m, the decline in the SED between 2-14 mu m appears best explained by self-absorption of the disk's thermal emission resulting in the system being dominated by scattered light in the mid-infrared. At 25 mm the SED rises again as the disk emission at last penetrates the extinction. The consequences of these results for our understanding of this prototype accretion disk system are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stapelfeldt, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 5 TC 16 Z9 16 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SP PUBL PY 1999 VL 427 BP 521 EP 524 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900111 ER PT S AU Stapelfeldt, K Padgett, D Brooke, TY AF Stapelfeldt, K Padgett, D Brooke, TY BE Cox, P Kessler, MF TI A survey for molecular hydrogen rotational emission in low-mass pre-main sequence stars SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA Special Publications LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE protoplanetary disks; young stars ID T-TAURI STARS; YOUNG STELLAR OBJECTS; OPHIUCHI CLOUD; CHAMELEON; H-2 AB We have used ISO/SWS to search for molecular hydrogen S(0) and S(1) rotational emission toward 14 low mass pre-main sequence stars located in the nearby Chamaeleon, Ophiuchus, and Taurus-Auriga star forming regions. Eight classical T Tauri stars and six weak line T Tauri stars were observed. The survey was motivated by model calculations which indicate that there should be enough warm gas in a circumstellar/protoplanetary disk to produce H-2 emission detectable by ISO. Emission was strongly detected toward the weak line T Tauri star SR 9, weakly detected toward three other targets, and not detected at all in the remaining 8 objects. For SR 9, the observed rotational temperature is 120 K. At this temperature, the observed H-2 line fluxes suggest a circumstellar gas mass comparable to that inferred from the millimeter continuum dust emission from this source. For the other three sources only the S(1) H-2 line was detected, and thus it is difficult to draw strong conclusions about the emission mechanism for them. These ISO results suggest that broader, more sensitive surveys with SOFIA or perhaps with SIRTF should be able to address the question of the gas dissipation timescale in a protoplanetary disk. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM krs@wfpc2-mail.jpl.nasa.gov RI Stapelfeldt, Karl/D-2721-2012 NR 15 TC 3 Z9 3 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SPEC PUBL PY 1999 VL 427 BP 525 EP 528 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900112 ER PT S AU Levine, D Morris, M Figer, D AF Levine, D Morris, M Figer, D BE Cox, P Kessler, MF TI Blowing a carbon-rich bubble in the Galactic Centre medium around the quintuplet SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE Galactic Center AB The HII Region known as the "Sickle", follows the rim of a large scale ring of emission faintly visible at 20 cm and clearly visible in the mid-IR but undetected in CO surveys. We have taken SWS full range spectra at 3 points along the rim of the "bubble" and one point of relatively low emission to its interior. We detect several fine-structure lines and strong PAH features, but molecular lines are weak or absent. C1 CALTECH, Jet Prop Lab, IPAC, SIRTF Sci Ctr, Pasadena, CA 91109 USA. RP Levine, D (reprint author), CALTECH, Jet Prop Lab, IPAC, SIRTF Sci Ctr, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SP PUBL PY 1999 VL 427 BP 699 EP 701 PN 1&2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900142 ER PT S AU Jarrett, TH Helou, G Van Buren, D Valjavec, E Condon, J AF Jarrett, TH Helou, G Van Buren, D Valjavec, E Condon, J BE Cox, P Kessler, MF TI Infrared study of the interacting galaxy pair UGC 12914/5 - "Taffy" SO UNIVERSE AS SEEN BY ISO, VOLS I AND II SE ESA Special Publications LA English DT Proceedings Paper CT Conference on the Universe as Seen by ISO CY OCT 20-23, 1998 CL PARIS, FRANCE SP European Spacy Agcy, Univ Paris, Inst Astrophysique Spatiale, Ctr Nat Etude Spatiale, Alcatel, Arianespace, IPAC, Despa, Observatoire Meudon, REOSC, SAP CEA Saclay DE galaxies : individual (UGC 12914/12915, VV254); interactions; ISM ID EMISSION AB We are conducting an infrared wavelength study of the nearby interacting spiral galaxy system, UGC 12914/12915 (VV 254), using ground-based near infrared and mid-infrared imaging and spectral observations using ISOCAM and PHT-S on the Infrared Space Observatory (ISO). VV 254 is one of the closest examples of a rarely occurring sub-class of interacting systems consisting of two counter-rotating spirals having suffered a nearly face-on collision only similar to 10(7) years past. Our ISOCAM imaging data spatially resolves the system, revealing two morphologically disturbed spiral galaxies, large scale dynamical ring and a connecting intergalactic bridge. The total mid-IR emission is dominated by the nucleus of the more compact companion, UGC 12915 (northern galaxy), having nearly double the mid-infrared photons as compared to the ringed UGC 12914 (southern galaxy). The total mid-infrared flux density is similar to 1.3 Jy, or about 5% of the total far-infrared flux density (IRAS bands). The near-/mid-infrared in conjunction with radio continuum data indicate that UGC 12915 is now undergoing vigorous star formation in or near its nucleus while UGC 12914 is more quiescent (possibly in a pre-starburst phase), and thus the off-center collision has influenced the ISM evolution unequally in the two galaxies. A large-scale ring, resonantly induced by the nearly face-on collision, is identified in LW2 (6 mm) and LW8 (11 mm) bands. Finally, the connecting bridge between the two spirals does contain dust in correct proportion to the observed atomic gas column density assuming the radiation field transiently heating the small dust grains is similar in intensity to what is observed in the solar neighborhood and high galactic latitude cirrus clouds. The detailed nature of colder dust (T < 100 K) is still uncertain owing to lack of resolution in the far-infrared. C1 CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91109 USA. EM jarrett@ipac.Caltech.edu; gxh@ipac.Caltech.edu NR 9 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-708-9 J9 ESA SPEC PUBL PY 1999 VL 427 BP 897 EP 900 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BN74P UT WOS:000082780900188 ER PT S AU Massa, D Prinja, RK AF Massa, D Prinja, RK BE Wolf, B Stahl, O Fullerton, AW TI UV wind variability in B supergiants and its implications for wind structures SO VARIABLE AND NON-SPHERICAL STELLAR WINDS IN LUMINOUS HOT STARS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT IAU Colloquium 169 on Variable and Non Spherical Stellar Winds in Luminous Hot Stars CY JUN 15-19, 1998 CL HEIDELBERG, GERMANY SP IAU, German Res Council ID STELLAR WIND; HD-64760 AB We discuss why B supergiant winds are particularly well suited for wind studies, and present or refer to dynamic spectra which suggest the presence of disks, bifurcated winds, shock formation, rotationally modulated winds and the spontaneous generation of wind enhancements. They underscore the strength and richness of wind variability in B supergiants and the challenges these phenomena present to theoretical studies of stellar winds. C1 NASA, Goddard Space Flight Ctr, Raytheon STX, Greenbelt, MD 20771 USA. RP Massa, D (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX, Code 631-0, Greenbelt, MD 20771 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65702-9 J9 LECT NOTES PHYS PY 1999 VL 523 BP 214 EP 217 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP35R UT WOS:000084832300033 ER PT S AU Barth, TJ AF Barth, TJ BE Palma, JML Dongarra, J Hernandez, V TI Computational fluid dynamics, structural analysis and mesh partioning techniques - Introduction SO VECTOR AND PARALLEL PROCESSING - VECPAR'98 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Editorial Material CT 3rd International Confernece on Vector And Parallel Processing (VECPAR 98) CY JUN 21-23, 1998 CL OPORTO, PORTUGAL SP Univ Porto, Fac Engn, Fdn Ciencia & Tecnol, European Off Aerospa Res & Dev, Fdn Dr Antonio Cupertino Miranda, Fdn Luso Amer Para Desenvolvimento, Fdn Comp Cient Nacl, Fdn Calouste Gulkbenkian, Univ Porto, Assoc Estudantes, Fac Engn, Camara Municipal Porto, Digital Equipment Portugal, Bull Portugal, ICL, Silicon Graph Inc, Porto Convent Bur, Portugal Telecom, Sist Integrados Comun Novos Equipamentos & Technol Lda C1 NASA, Ames Res Ctr, Informat Sci Directorate, NAS Div, Moffett Field, CA 94035 USA. RP Barth, TJ (reprint author), NASA, Ames Res Ctr, Informat Sci Directorate, NAS Div, Mail Stop T27A-1, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66228-6 J9 LECT NOTES COMPUT SC PY 1999 VL 1573 BP 171 EP 175 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BP13C UT WOS:000084209000014 ER PT S AU Barth, TJ Chan, TF Tang, WP AF Barth, TJ Chan, TF Tang, WP BE Palma, JML Dongarra, J Hernandez, V TI Parallel domain-decomposition preconditioning for computational fluid dynamics - Invited talk SO VECTOR AND PARALLEL PROCESSING - VECPAR'98 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Confernece on Vector And Parallel Processing (VECPAR 98) CY JUN 21-23, 1998 CL OPORTO, PORTUGAL SP Univ Porto, Fac Engn, Fdn Ciencia & Tecnol, European Off Aerospa Res & Dev, Fdn Dr Antonio Cupertino Miranda, Fdn Luso Amer Para Desenvolvimento, Fdn Comp Cient Nacl, Fdn Calouste Gulkbenkian, Univ Porto, Assoc Estudantes, Fac Engn, Camara Municipal Porto, Digital Equipment Portugal, Bull Portugal, ICL, Silicon Graph Inc, Porto Convent Bur, Portugal Telecom, Sist Integrados Comun Novos Equipamentos & Technol Lda ID FINITE-ELEMENT FORMULATION; ELLIPTIC PROBLEMS; ALGORITHMS; SYSTEMS AB Algebraic preconditioning algorithms suitable for computational fluid dynamics (CFD) based on overlapping and non-overlapping domain decomposition (DD) are considered. Specific distinction is given to techniques well-suited for time-dependent and steady-state computations of fluid flow. For time-dependent flow calculations, the overlapping Schwarz algorithm suggested by Wu et al. [28] together with stabilised (upwind) spatial discretisation shows acceptable scalability and parallel performance without requiring a coarse space correction, For steady-state flow computations, a family of non-overlapping Schur complement DD techniques are developed. In the Schur complement DD technique, the triangulation is first partitioned into a number of non-overlapping subdomains and interfaces. The permutation of the mesh vertices based on subdomains and interfaces induces a natural 2 x 2 block partitioning of the discretisation matrix. Exact LU factorisation of this block system introduces a Schur complement matrix which couples subdomains and the interface together. A family of simplifying techniques for constructing the Schur complement and applying the 2 x 2 block system as a DD preconditioner are developed. Sample fluid flow calculations are presented to demonstrate performance characteristics of the simplified preconditioners. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Los Angeles, Dept Math, Los Angeles, CA 90095 USA. Univ Waterloo, Dept Comp Sci, Waterloo, ON N2L 3G1, Canada. RP Barth, TJ (reprint author), NASA, Ames Res Ctr, Mail Stop T27A-1, Moffett Field, CA 94035 USA. RI Chan, Tony/A-4166-2013 NR 29 TC 0 Z9 0 U1 0 U2 2 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66228-6 J9 LECT NOTES COMPUT SC PY 1999 VL 1573 BP 176 EP 202 PG 27 WC Computer Science, Theory & Methods SC Computer Science GA BP13C UT WOS:000084209000015 ER PT S AU Sawyer, W Takacs, L da Silva, A Lyster, P AF Sawyer, W Takacs, L da Silva, A Lyster, P BE Palma, JML Dongarra, J Hernandez, V TI Parallel grid manipulations in earth science calculations SO VECTOR AND PARALLEL PROCESSING - VECPAR'98 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Confernece on Vector And Parallel Processing (VECPAR 98) CY JUN 21-23, 1998 CL OPORTO, PORTUGAL SP Univ Porto, Fac Engn, Fdn Ciencia & Tecnol, European Off Aerospa Res & Dev, Fdn Dr Antonio Cupertino Miranda, Fdn Luso Amer Para Desenvolvimento, Fdn Comp Cient Nacl, Fdn Calouste Gulkbenkian, Univ Porto, Assoc Estudantes, Fac Engn, Camara Municipal Porto, Digital Equipment Portugal, Bull Portugal, ICL, Silicon Graph Inc, Porto Convent Bur, Portugal Telecom, Sist Integrados Comun Novos Equipamentos & Technol Lda AB We introduce the parallel grid manipulations needed in the Earth Science applications currently being implemented at the Data Assimilation Office (DAO) of the National Aeronautics and Space Administration (NASA). Due to real-time constraints the DAO software must run efficiently on parallel computers. Numerous grids, structured and unstructured are employed in the software. The DAO has implemented the PILGRIM library to support multiple grids and the various grid transformations between them, e.g., interpolations, rotations, prolongations and restrictions. It allows grids to be distributed over an array of processing elements (PEs) and manipulated with high parallel efficiency. The design of PILGRIM closely follows the DAO's requirements, but it can support other applications which employ certain types of grids. New grid definitions can be written to support still others. Results illustrate that PILGRIM can solve grid manipulation problems efficiently on parallel platforms such as the Cray T3E. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. RP Sawyer, W (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 9103, Greenbelt, MD 20771 USA. RI da Silva, Arlindo/D-6301-2012 OI da Silva, Arlindo/0000-0002-3381-4030 NR 17 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-66228-6 J9 LECT NOTES COMPUT SC PY 1999 VL 1573 BP 666 EP 679 PG 14 WC Computer Science, Theory & Methods SC Computer Science GA BP13C UT WOS:000084209000050 ER PT J AU Masson, GS Mestre, DR Stone, LS AF Masson, GS Mestre, DR Stone, LS TI Speed tuning of motion segmentation and discrimination SO VISION RESEARCH LA English DT Article DE motion perception; speed segmentation; speed discrimination; transparency; structure-from-motion ID TEMPORAL VISUAL AREA; RANDOM-DOT PATTERNS; TRANSPARENT MOTION; MACAQUE MONKEY; DIRECTION SELECTIVITY; FUNCTIONAL-PROPERTIES; MOVING PATTERNS; VELOCITY; PERCEPTION; MT AB Motion transparency requires that the visual system distinguish different motion Vectors and selectively integrate similar motion vectors over space into the perception of multiple surfaces moving through or over each other. Using large-field (7 degrees x 7 degrees) displays containing two populations of random-dots moving in the same (horizontal) direction but at different speeds, we examined speed-based segmentation by measuring the speed difference above which observers can perceive two moving surfaces. We systematically investigated this 'speed-segmentation' threshold as a function of speed and stimulus duration, and found that it increases sharply for speeds above approximate to 8 degrees/s. In addition, speed-segmentation thresholds decrease with stimulus duration out to approximate to 200 ms. In contrast, under matched conditions, speed-discrimination thresholds stay low at least out to 16 degrees/s and decrease with increasing stimulus duration at a faster rate than for speed segmentation. Thus, motion segmentation and motion discrimination exhibit different speed selectivity and different temporal integration characteristics. Results are discussed in terms of the speed preferences of different neuronal populations within the primate visual cortex. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 CNRS, Ctr Rech Neurosci Cognit, F-13402 Marseille, France. NASA, Human Informat Proc Res Branch, Human Factors Res & Technol Div, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Masson, GS (reprint author), CNRS, Ctr Rech Neurosci Cognit, F-13402 Marseille, France. RI Mestre, Daniel/J-9526-2015; MASSON, Guillaume/G-4615-2012 OI Mestre, Daniel/0000-0002-0399-4747; NR 61 TC 22 Z9 22 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0042-6989 J9 VISION RES JI Vision Res. PY 1999 VL 39 IS 26 BP 4297 EP 4308 DI 10.1016/S0042-6989(99)00143-1 PG 12 WC Neurosciences; Ophthalmology SC Neurosciences & Neurology; Ophthalmology GA 258FN UT WOS:000083827600001 PM 10789424 ER PT B AU Blake, D AF Blake, D BE Roos, YH Leslie, RB Lillford, PJ TI Occurrence and forms of water and ice on the Earth and in the universe, and the origin(s) of life SO WATER MANAGEMENT IN THE DESIGN AND DISTRIBUTION OF QUALITY FOODS LA English DT Proceedings Paper CT 7th International Symposium on the properties of water in Food (ISOPOW 7) CY MAY 30-JUN 04, 1998 CL UNITAS CONGRESS CTR, HELSINKI, FINLAND SP Acad Finland, Ajinomoto Co Inc, Assoc Italiana Tecol Alimentare, City Helsinki, Coca Cola, Danone Grp, Biscuit Div, Central Sci Grp, European Commiss, Finnair, Finnish Food Res Fdn, Firmenich SA, Grand Metroploilan, INRA, IUFoST, Kelloggs, Kikkoman Corp, Nabisco Inc, SCI AJ Bank Funds, Technomic Publishing Co Inc, Unilever Res, Univ Helsinki, Weetabix Limited HO UNITAS CONGRESS CTR ID AMORPHOUS SOLID WATER; ASTROPHYSICAL IMPLICATIONS; COMETARY ICE; INTERSTELLAR GRAINS; GLASS-TRANSITION; SOLAR-SYSTEM; LIQUID WATER; PRESSURE; CLATHRATE; ANALOGS AB The natural history of the biogenic elements (H, C, O, N, P, and S) from their first association within cold molecular clouds to their delivery to the Earth during the late bombardment of the inner solar system, is intimately linked to water ice. The earliest organic compounds were formed in cold interstellar molecular clouds as a result of UV and thermal processing of sub-mu m ice grains, which enclose trapped carbon and nitrogen-containing free radicals. Structural changes in the water ice host underlie and control important macroscopic phenomena, such as the outgassing of volatiles, the rates of chemical reactions, and processing and retention of organic compounds. Prebiotic organic material was in all likelihood delivered to the early Earth in a pristine state, as a consequence of its sequestration within a protective water ice host. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Blake, D (reprint author), NASA, Ames Res Ctr, MS 239-4, Moffett Field, CA 94035 USA. NR 75 TC 0 Z9 0 U1 1 U2 3 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-763-6 PY 1999 BP 23 EP 51 PG 29 WC Food Science & Technology SC Food Science & Technology GA BQ55L UT WOS:000088746100002 ER PT J AU Dietrich, AM Mirlohi, S DaCosta, WF Dodd, JP Sauer, R Homan, M Schultz, J AF Dietrich, AM Mirlohi, S DaCosta, WF Dodd, JP Sauer, R Homan, M Schultz, J TI Flavor profile analysis and GC/MS detection of phenolic iodinated disinfection byproducts in drinking water for the USA space program SO WATER SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Symposium on Off-Flavours in the Aquatic Environment CY OCT 13-16, 1997 CL PARIS, FRANCE SP French Natl Comm IAWQ, Int Assoc Water Quality, Aguas Barcelona, CIRSEE Lyonnaise Eaux, Compagnie Gen Eaux, SAGEP Paris DE diiodophenol; iodine; iodophenol; odor; phenol; triiodophenol AB Reactions of iodine and phenol were investigated to determine which iodophenols were produced and their odor properties. The research was performed in support of the USA space program that applies iodine to disinfect potable water for spacecraft use. Higher concentrations (50 mg/l) and higher iodine:phenol (e.g. 10:1) ratios resulted in the formation of greater iodophenol concentrations and higher substituted iodophenols. The reactions were fast and nearly complete within 1 hour. For pH 5.5 and 8 and all iodine:phenol ratios, formation of monosubstituted compounds indicated that 2-iodophenol was favored over 4-iodophenol. At the intermediate iodine:phenol ratios of 1:1 and 2:1, substantial amounts of the diiodophenols formed and persisted for up to 32 days. The diiodophenols were not detected at iodine:phenol ratios of 0.2:1 and 10:1. The compound 2,4,6-triiodophenol was the major product formed at a 10:1 iodine:phenol ratio and the formation of this trisubstituted phenol appeared nearly complete. Odor evaluation indicated that the iodophenols have much lower odor threshold concentrations (OTC) than phenol. The 2- and 4- iodophenol had OTC values of congruent to 1 and 500 mu g/l, respectively, with odors described as "medicinal, phenol, chemical". (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved. C1 Virginia Polytech Inst & State Univ, Dept Civil & Environm Engn, Blacksburg, VA 24061 USA. Univ Estadual Maringa, Dept Chem, Maringa, Parana, Brazil. NASA, Lyndon B Johnson Space Ctr, Water & Food Anal Lab, Houston, TX 77058 USA. RP Dietrich, AM (reprint author), Virginia Polytech Inst & State Univ, Dept Civil & Environm Engn, Blacksburg, VA 24061 USA. RI Lucas, Elizabeth/E-2733-2010 NR 13 TC 18 Z9 20 U1 2 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1223 J9 WATER SCI TECHNOL JI Water Sci. Technol. PY 1999 VL 40 IS 6 BP 45 EP 51 DI 10.1016/S0273-1223(99)00536-3 PG 7 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 249GF UT WOS:000083324400006 ER PT S AU Le Moigne, J Zavorine, I AF Le Moigne, J Zavorine, I BE Szu, HH TI An application of rotation- and translation-invariant overcomplete wavelets to the registration of remotely sensed imagery SO WAVELET APPLICATIONS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Wavelet Applications VI CY APR 06-08, 1999 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers AB A wavelet-based image registration approach has previously been proposed by the authors. In this work, wavelet coefficient maxima obtained from an orthogonal wavelet decomposition using Daubechies filters were utilized to register images in a multi-resolution fashion. Tested on several remote sensing datasets, this method gave very encouraging results, Despite the lack of translation-invariance of these filters, we showed that when using cross-correlation as a feature matching technique, features of size larger than twice the size of the filters are correctly registered by using the low-frequency subbands of the Daubechies wavelet decomposition. Nevertheless, high-frequency subbands are still sensitive to translation effects. In this work, we are considering a rotation- and translation-invariant representation developed by E. Simoncelli and integrate it in our image registration scheme. The two types of filters, Daubechies and Simoncelli filters, are then being compared from a registration point of view, utilizing synthetic data as well as data from the Landsat/Thematic Mapper(TM) and from the NOAA Advanced Very High Resolution Radiometer (AVHRR). C1 NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Le Moigne, J (reprint author), NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Code 661, Greenbelt, MD 20771 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3197-4 J9 P SOC PHOTO-OPT INS PY 1999 VL 3723 BP 130 EP 140 DI 10.1117/12.342921 PG 11 WC Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM94B UT WOS:000080194100013 ER PT J AU Uzunalioglu, H Akyildiz, IF Yesha, Y Yen, W AF Uzunalioglu, H Akyildiz, IF Yesha, Y Yen, W TI Footprint handover rerouting protocol for low Earth orbit satellite networks SO WIRELESS NETWORKS LA English DT Article ID SYSTEMS AB Low Earth Orbit (LEO) satellite networks will be an integral part of the next generation telecommunications infrastructures. In a LEO satellite network, satellites and their individual coverage areas move relative to a fixed observer on Earth. To ensure that ongoing calls are not disrupted as a result of satellite movement, calls should be transferred or handed over to new satellites. Since two satellites are involved in a satellite handover, connection route should be modified to include the new satellite into the connection route. The route change can be achieved by augmenting the existing route with the new satellite or by completely rerouting the connection. Route augmentation is simple to implement, however the resulting route is not optimal. Complete rerouting achieves optimal routes at the expense of signaling overhead. In this paper, we introduce a handover rerouting protocol that maintains the optimality of the initial route without performing a routing algorithm after intersatellite handovers. The FHRP makes use of the footprints of the satellites in the initial route as the reference for rerouting. More specifically, after an optimum route has been determined during the call establishment process, the FHRP ensures that the new route due to handover is also optimum. The FHRP demands easy processing, signaling, and storage costs. The performance results show that the FHRP performs similar to a network without any handovers in terms of call blocking probability. C1 Lucent Technol, Bell Labs Adv Technol, Red Bank, NJ 07701 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Broadband & Wireless Networking Lab, Atlanta, GA 30332 USA. Univ Maryland, Dept Elect Engn & Comp Sci, Baltimore, MD 21250 USA. NASA, CESDIS, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Mitsubishi Telecommun Network Div, Duluth, GA 30096 USA. RP Uzunalioglu, H (reprint author), Lucent Technol, Bell Labs Adv Technol, 101 Crawfords Corner Rd, Red Bank, NJ 07701 USA. RI Akyildiz, Ian/G-7136-2011 OI Akyildiz, Ian/0000-0002-8099-3529 NR 17 TC 25 Z9 29 U1 0 U2 6 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1022-0038 J9 WIREL NETW JI Wirel. Netw. PY 1999 VL 5 IS 5 BP 327 EP 337 DI 10.1023/A:1019127801155 PG 11 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 245LR UT WOS:000083110900003 ER PT S AU Pollock, AMT Corcoran, MF Stevens, IR AF Pollock, AMT Corcoran, MF Stevens, IR CA XMEGA Grp BE VanderHucht, KA Koenigsberger, G Eenens, PRJ TI The X-ray history of WR 140 in modest comparison with the radio SO WOLF-RAYET PHENOMENA IN MASSIVE STARS AND STARBURST GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 193rd Symposium of the International-Astronomical-Union CY NOV 03-07, 1998 CL PUERTO VALLARTA, MEXICO SP Int Astron Union ID BINARY AB We present the X-ray lightcurve of the canonical colliding-wind binary WR 140 from the time of the last periastron through late 1997. Variations in column density, and intrinsic and absorbed X-ray flux agree well with the expectations of colliding wind theory in which the winds from the stars are spherically symmetric. C1 Comp & Sci Co Ltd, Sheffield S10 3GS, S Yorkshire, England. ISO, Sci Operat Ctr, Div Astrophys, ESA,SSD, E-28080 Madrid, Spain. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Lanham, MD 20706 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. RP Pollock, AMT (reprint author), Comp & Sci Co Ltd, 230 Graham Rd, Sheffield S10 3GS, S Yorkshire, England. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-004-8 J9 IAU SYMP PY 1999 IS 193 BP 388 EP 389 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU34M UT WOS:000175726300102 ER PT S AU Heap, SR AF Heap, SR BE VanderHucht, KA Koenigsberger, G Eenens, PRJ TI R136a and its implications for understanding Wolf-Rayet stars and Wolf-Rayet galaxies SO WOLF-RAYET PHENOMENA IN MASSIVE STARS AND STARBURST GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 193rd Symposium of the International-Astronomical-Union CY NOV 03-07, 1998 CL PUERTO VALLARTA, MEXICO SP Int Astron Union ID LARGE-MAGELLANIC-CLOUD; HUBBLE-SPACE-TELESCOPE; MASS-LOSS RATES; 30 DORADUS AB We argue that the WR phenomenon is simply a consequence of very high mass-loss rates (i.e., it is independent of initial mass, composition, or evolutionary status) and that it occurs in very massive main-sequence stars. We explore this argument using new HST observations of R 136a, the compact cluster containing three high-mass WR stars on the main sequence. We suggest that the underlying cause of the WR phenomemon in these stars is mass-loss enhanced by rapid rotation. Finally, we explore the implications of luminous, main-sequence WR stars for interpreting unresolved WR star clusters and galaxies. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-004-8 J9 IAU SYMP PY 1999 IS 193 BP 412 EP 417 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU34M UT WOS:000175726300111 ER PT S AU Figer, DF Kim, SS Morris, M Serabyn, E AF Figer, DF Kim, SS Morris, M Serabyn, E BE VanderHucht, KA Koenigsberger, G Eenens, PRJ TI Super star clusters in the Galactic Center as revealed by HST-NICMOS SO WOLF-RAYET PHENOMENA IN MASSIVE STARS AND STARBURST GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 193rd Symposium of the International-Astronomical-Union CY NOV 03-07, 1998 CL PUERTO VALLARTA, MEXICO SP Int Astron Union ID MASSIVE STARS; HOT STARS; MILKY-WAY AB The three massive clusters in the Galactic Center are not only the most massive young clusters in the Galaxy, but they harbor more Wolf-Rayet stars than any other starburst region in the Local Group. An understanding of their stellar content will be valuable for extending models to starburst regions in other galaxies. We present HST-NICMOS images, luminosity functions, and color-magnitude diagrams of two of these: the Quintuplet and Arches clusters. The images allow the detection of stars over 6 magnitudes fainter than ever before and reveal previously undetected multiple star systems. For the first time, we clearly identify the main sequence in the Quintuplet cluster, and we extend earlier detections of the main sequence in the Arches cluster to M-initial < 10 M-circle dot. We estimate that the Arches cluster has an initial mass function slope which is greater than the Salpeter value. Given their stellar content, the Galactic Center clusters provide both the best nearby examples of super star clusters and the best nearby locale in which to investigate WR phenomena in starburst galaxies and galactic nuclei. We discuss the content of the Galactic Center clusters, with a particular emphasis on how they compare to other massive clusters of the local group. We expect that many of the massive stars in the Galactic Center will soon evolve to become WR stars, and eventually become supernovae at a rate of similar to1 per 20 000 years for the next several Myr. We note that our preliminary N-body simulations suggest that such dense clusters are short-lived in the strong tidal field of the Galactic Center, consistent with the fact that no older dense clusters are seen in the central 50 pc. This implies a star formation rate of 5(10(-3)) M-circle dot yr(-1) in the Galactic Center. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Korea Adv Inst Sci & Technol, Dept Phys, Space Sci Lab, Taejon 305701, South Korea. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Figer, DF (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-004-8 J9 IAU SYMP PY 1999 IS 193 BP 459 EP 469 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU34M UT WOS:000175726300116 ER PT S AU de Koter, A Heap, SR Hillier, DJ Hubeny, I AF de Koter, A Heap, SR Hillier, DJ Hubeny, I BE VanderHucht, KA Koenigsberger, G Eenens, PRJ TI Synthetic spectra of young starbursts: exploring the metallicity dependence SO WOLF-RAYET PHENOMENA IN MASSIVE STARS AND STARBURST GALAXIES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 193rd Symposium of the International-Astronomical-Union CY NOV 03-07, 1998 CL PUERTO VALLARTA, MEXICO SP Int Astron Union AB We present first results of fully synthetic UV spectra of young starbursts. With this we mean that the spectra used to model the OB and WN stars result from unified non-LTE model atmospheres, in which stellar winds are accounted for. An important aim of this project is to construct meaningful models for young starbursts at low metallicities. We discuss the presence of He II emission as a function of maximum initial mass and age of the burst. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NASA, Goddard Space Flight Ctr, Natl Opt Astron Observ, AURA, Greenbelt, MD 20771 USA. RP de Koter, A (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-004-8 J9 IAU SYMP PY 1999 IS 193 BP 485 EP 486 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU34M UT WOS:000175726300125 ER PT S AU Wilson, SD AF Wilson, SD BE Selby, CC TI Reflections on a career in the aerospace industry SO WOMEN IN SCIENCE AND ENGINEERING: CHOICES FOR SUCCESS SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT Conference on Choices and Successes - Women in Science and Engineering CY MAR 12-13, 1998 CL NEW YORK, NEW YORK SP Lounsbery Fdn, Avon Prod Inc, IBM Res C1 NASA, Lyndon B Johnson Space Ctr, Astronaut Appearance Off, Houston, TX 77058 USA. RP Wilson, SD (reprint author), NASA, Lyndon B Johnson Space Ctr, Astronaut Appearance Off, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-166-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1999 VL 869 BP 110 EP 112 DI 10.1111/j.1749-6632.1999.tb08364.x PG 3 WC Multidisciplinary Sciences; Women's Studies SC Science & Technology - Other Topics; Women's Studies GA BN02L UT WOS:000080423400018 ER PT S AU Huntoon, CL AF Huntoon, CL BE Selby, CC TI Opening doors for women in space: A perspective from the National Aeronautics and Space Administration SO WOMEN IN SCIENCE AND ENGINEERING: CHOICES FOR SUCCESS SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT Conference on Choices and Successes - Women in Science and Engineering CY MAR 12-13, 1998 CL NEW YORK, NEW YORK SP Lounsbery Fdn, Avon Prod Inc, IBM Res C1 NASA, Arlington, VA 22202 USA. RP Huntoon, CL (reprint author), NASA, 1501 Crystal Dr,Apt 1028, Arlington, VA 22202 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-166-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1999 VL 869 BP 204 EP 206 DI 10.1111/j.1749-6632.1999.tb08376.x PG 3 WC Multidisciplinary Sciences; Women's Studies SC Science & Technology - Other Topics; Women's Studies GA BN02L UT WOS:000080423400030 PM 11536902 ER PT B AU van Belle, GT AF van Belle, GT BE Unwin, S Stachnik, R TI Predicting stellar angular sizes SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID VISUAL SURFACE BRIGHTNESS; EFFECTIVE TEMPERATURES; SPECTRAL TYPES; DIAMETERS; STARS; CALIBRATION AB Reliable prediction of stellar diameters, particularly angular diameters, is a useful and necessary tool for the increasing number of milliarcsecond resolution studies being carried out in the astronomical community. A new and accurate technique of predicting angular sizes is presented for giant and supergiant stars, and for more evolved sources such as carbon stars and Mira variables. This technique uses observed K and either V or B broad-band photometry to predict V = 0 or B = 0 zero magnitude angular sizes; which are then readily scaled to the apparent angular sizes with the V or B photometry. The spread in the relationship is 11-12% for giant and supergiant stars, and for evolved sources, results are at the 20-26% level. Compared to other simple predictions of angular size, such as linear radius-distance methods or black-body estimates, zero magnitude angular size predictions can provide apparent angular sizes with errors that are 2 to 5 times smaller. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP van Belle, GT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 64 EP 73 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300010 ER PT B AU Shaya, E Phelps, S Peebles, PJE Tully, RB AF Shaya, E Phelps, S Peebles, PJE Tully, RB BE Unwin, S Stachnik, R TI Masses and mass distributions of galaxies calculated using Numerical Action and proper motions from SIM SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID NEARBY GALAXIES AB The Numerical Action method is an elegant, non-chaotic technique for calculating the full trajectories of systems in a cosmological context. It has been used extensively on the Local Group in a series of papers by Peebles and for the Local Supercluster by the authors. We are now extending this analysis to find trajectories back to t=0 for about 150 individual galaxies wit hin 6 Mpc plus about 1200 groups of galaxies beyond this domain extending to 3000 km/s. Our repertoire of tools include codes that hold present distances constant and predict possible redshifts, hold present redshifts fixed and predict possible distances, and iterate on distances until a proper redshift is found. We are also developing a new action principal to directly deter mine possible individual galaxy masses and mass distributions from a set of observed distances, redshifts, and proper motions. The addition of proper motions obtained by SIM will allow calculation of the mass distributions of galaxies and of groups, measurement of the dynamical friction between dark matter and galaxies, detection of additional mass other than that of known galaxies, if it exists, and a rigorous testing of the basic theories of cosmological structure formation. C1 NASA, Goddard Space Flight Ctr, RITSS, Greenbelt, MD 20771 USA. RP Shaya, E (reprint author), NASA, Goddard Space Flight Ctr, RITSS, Code 631, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 74 EP 77 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300011 ER PT B AU Shao, M Baron, R AF Shao, M Baron, R BE Unwin, S Stachnik, R TI The practice of astrometry in space with the space interferometry mission instrument SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB A short tutorial covering the basics of astrometry and interferometry relating to the SIM mission is presented. The material includes: a description of interferometry, the definition of delay, how it is measured how it is converted into an angle, some of the difficulties of space interferometry, global and inertial coordinate frames, the SIM Grid and error sources associated with the mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shao, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 107 EP 113 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300018 ER PT B AU Turyshev, SG AF Turyshev, SG BE Unwin, S Stachnik, R TI Relativistic stellar aberration requirements for the space interferometry mission SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB We summarize here results of our recent study of the relativistic stellar aberration requirements for the Space Interferometry Mission (SIM). Based on a simplified model for differential astrometric observations with a free-flying single-baseline interferometer, we analyzed the astrometric errors introduced by imperfect metrology, inaccurate baseline length estimations, and those due to relativistic orbital motion of the spacecraft. We have shown that motion of the spacecraft in the direction perpendicular to a tile provides the most stringent requirement on the accuracy of knowledge of the barycentric velocity of the spacecraft. We consider a number of non-gravitational forces acting on the spacecraft and estimate their impact on the navigational accuracy. We show that, if not properly accounted, the solar radiation pressure and the anisotropic thermal radiation of the spacecraft may have a significant impact on the accuracy of future astrometric observations with SIM. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Turyshev, SG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 142 EP 146 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300023 ER PT B AU Booth, AJ Colavita, MM Shao, M Swanson, PN van Belle, GT Crawford, SL Palmer, DL Reder, LJ Serabyn, E Swain, MR Vashist, G Wallace, JK Wizinowich, P Kendrick, R Lupton, W Walker, J AF Booth, AJ Colavita, MM Shao, M Swanson, PN van Belle, GT Crawford, SL Palmer, DL Reder, LJ Serabyn, E Swain, MR Vashist, G Wallace, JK Wizinowich, P Kendrick, R Lupton, W Walker, J BE Unwin, S Stachnik, R TI The Keck Interferometer: Instrument overview and proposed science SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID ASTROMETRY AB One of the keg ground-based components of NASA's Origins Program is the Keck Interferometer being developed by JPL and CARA. The interferometer will combine the two 10-m Keck telescopes with four proposed 1.8-m outrigger telescopes located at the periphery of the Keck site on Mauna Kea. incorporation of adaptive optics on the Keck telescopes with cophasing using an isoplanatic reference provides high sensitivity. Back-end instrumentation will include two-way combiners for cophasing and single-baseline measurements, a nulling combiner for high-dynamic-range measurements. and a multi-way imaging combiner. Science objectives include the characterization of zodiacal dust around other stars, detection of hot Jupiters and brown dwarfs through multicolor differential-phase measurements, astrometric searches for planets down to Uranus-mass, and a wide range of infrared imaging. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Booth, AJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 13 Z9 13 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 256 EP 263 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300040 ER PT B AU Gorham, PW Folkner, WM Blackwood, GH AF Gorham, PW Folkner, WM Blackwood, GH BE Unwin, S Stachnik, R TI Enabling concepts for a dual spacecraft formation-flying optical interferometer for NASA's ST3 mission SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB We present the enabling concept and technology for a dual spacecraft formation-flying optical interferometer, to be launched into a deep space orbit as Space Technology 3 in 2003. The combiner spacecraft. makes use of a nested cat's eye delay line configuration that minimizes wavefront distortion and stores 20 m of optical pathlength in a package of similar to 1.5 m length. A parabolic trajectory for the secondary collector spacecraft enables baselines of up to 200 m for a fixed 20 m stored delay and spacecraft separations of up to 1 km. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gorham, PW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 359 EP 365 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300055 ER PT B AU Lay, OP Blackwood, GH Dubovitsky, S Gorham, PW Linfield, RP AF Lay, OP Blackwood, GH Dubovitsky, S Gorham, PW Linfield, RP BE Unwin, S Stachnik, R TI Design of the ST3 formation flying interferometer SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB The Space Technology 3 mission (formerly Deep Space 3), scheduled for launch in 2003, will be the first long baseline optical interferometer in space. The interferometer will operate in both a single spacecraft mode and a formation Aging mode using two spacecraft with a separation of up to 1 km. The primary goal is to validate interferometer and formation flying technology for future missions, but ST3 is also designed to return scientific data within its cost and mission constraints. This paper presents an overview of the current design, highlighting some of the technical challenges that must be overcome. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lay, OP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 366 EP 372 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300056 ER PT B AU Gezari, D AF Gezari, D BE Unwin, S Stachnik, R TI A rotating space interferometer with variable baselines and low power consumption SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB A new concept is presented for a large, rotating space interferometer which would achieve full u,v plane coverage with reasonably uniform integration times, yet once set in motion no additional energy would be required to change collector separations, maintain constant baseline rotation rates, or to counteract centrifugal forces on the collectors. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gezari, D (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 385 EP 388 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300060 ER PT B AU Beichman, CA Velusamy, T AF Beichman, CA Velusamy, T BE Unwin, S Stachnik, R TI Sensitivity of the TPF interferometer for planet detection SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID EXTRASOLAR PLANETS AB The Terrestrial Planet Finder (TPF) offers the prospect of revolutionizing humanity's perception of its own place in the Universe by identifying habitable and possibly even Life-bearing planets orbiting other stars. TPF will be able to find planets that are like the Earth in essential respects: warm with water and an oxygen-containing atmosphere. This paper introduces some of the issues that define the sensitivity of TPF for planet detection. TPF will also be able to image astrophysical sources with sub-milli-arcsecond resolution, but that topic is beyond the scope of this paper. The major conclusion of this paper is that a nulling interferometer operating at 1 AU with four 3.5-m telescopes can detect and characterize Earth-like planets as far away as 15 pc. A smaller system using similar to 2.5-m apertures could still detect Earth-like planets but would not be able to search for signs of life, such as ozone, in any but the nearest planetary systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Beichman, CA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 6 Z9 6 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 408 EP 422 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300064 ER PT B AU Lawson, PR Dumont, PJ Colavita, MM AF Lawson, PR Dumont, PJ Colavita, MM BE Unwin, S Stachnik, R TI Interferometer designs for the Terrestrial Planet Finder SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID NULLING INTERFEROMETER; EXTRASOLAR PLANETS; ARRAY CONFIGURATIONS; SEARCH AB The Terrestrial Planet Finder (TPF) is a space-based infrared interferometer that will combine high sensitivity and spatial resolution to detect and characterize planetary systems within 15 pc of our sun. TPF is a key element in NASA's Origins Program and is currently under study in its Pre-Formulation Phase. We review some of the interferometer designs that have been considered for starlight nulling, with particular attention to the architecture and subsystems of the central beam-combiner. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lawson, PR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lawson@huey.jpl.nasa.gov NR 17 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 423 EP 429 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300065 ER PT B AU Velusamy, T Beichman, CA Shao, M AF Velusamy, T Beichman, CA Shao, M BE Unwin, S Stachnik, R TI A dual 3-element nulling interferometer for TPF SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA ID EXTRASOLAR PLANETS AB We present an interferometer design that provides a null at, the star and a direct measurement of both visibility amplitude and phase of the planets. Six telescopes are configured to form two identical nulling interferometers. Each nulling interferometer with 3 telescopes, aperture sizes (1:2:1) on a baseline 30 - 50 m; produces a theta(4) null. They are placed on a longer baseline (similar to 100 - 1000 m). The null beams are combined to produce a chopped output, by introducing a phase shift in one of the beams, and by switching it between 0 degrees and 180 degrees (cosine chop) or between 90 degrees and 270 degrees (sine chop). The sine/cos chops measure directly the complex visibility of the planets. Simple synthesis techniques are used for image reconstruction by measuring the visibilities in a number of u-v points by rotating the baselines. This scheme has an enhanced capability for planet detection and characterization. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Velusamy, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 430 EP 436 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300066 ER PT B AU Serabyn, E Wallace, JK Nguyen, HT Schmidtlin, EGH Hardy, GJ AF Serabyn, E Wallace, JK Nguyen, HT Schmidtlin, EGH Hardy, GJ BE Unwin, S Stachnik, R TI Nulling interferometry: Working on the dark fringe SO WORKING ON THE FRINGE: OPTICAL AND IR INTERFEROMETRY FROM GROUND AND SPACE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Working on the Fringe - Optical and IR Interferometry from Ground and Space CY MAY 24-27, 1999 CL DANA POINT, CA AB Deep nulling of both laser and thermal radiation has been demonstrated in the laboratory at visible wavelengths, by means of a rotational shearing interferometer (RSI) coupled to single-mode input and output fibers. To date, the best null depth obtained with a laser-diode source is 8 x 10(-6). The laser-diode null has also been passively stabilized to the few x 10(-5) level, implying a short-term interferometer stability of approximate to 1 nm. A transient null depth of 2 x 10(-4) has also been achieved on a filtered, single-polarization, white-light source of 8% bandwidth. This null depth exceeds that which simple destructive interference in a standard ''constructive" interferometer can provide, thus demonstrating the more achromatic nature of the central null in RSIs. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Serabyn, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-020-X J9 ASTR SOC P PY 1999 VL 194 BP 437 EP 442 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP85M UT WOS:000086435300067 ER PT S AU Corcoran, MF AF Corcoran, MF BE Morrell, NL Niemela, VS Barba, RH TI X-ray emission from massive stars in open clusters SO WORKSHOP ON HOT STARS IN OPEN CLUSTERS OF THE GALAXY AND THE MAGELLANIC CLOUDS SE REVISTA MEXICANA DE ASTRONOMIA Y ASTROFISICA, SERIE DE CONFERENCIAS LA English DT Proceedings Paper CT Workshop on Hot Stars in Open Clusters of the Galaxy and the Magellanic Clouds CY DEC 01-05, 1997 CL UNIV NACL LA PLATA, LA PLATA, ARGENTINA SP La Plat Natl Univ, UNESCO, Argentine Astron Assoc HO UNIV NACL LA PLATA DE X-rays : stars; open clusters and associations : (individual) (SCO OB1; CYG OB2; TR14; TR16; CO 228) ID O-TYPE STARS; ETA-CARINAE; ZETA-ORIONIS; CYG OB2; ROSAT; VARIABILITY; NEBULA; PUPPIS; WINDS AB I present a review of studies of X-ray emission from massive O, B, and WR stars in open clusters based mostly on data from the ROSAT X-ray observatory. Such open cluster studies can address the dependence of the X-ray emission from massive stars on stellar age and metallicity, on local environment, and explore questions of the generation of diffuse X-ray emission and cluster history and the influence of X-ray emission on the parent molecular cloud. C1 NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. NR 32 TC 5 Z9 5 U1 0 U2 0 PU UNIVERSIDAD NACIONAL AUTONOMA MEXICO INSTITUTO ASTRONOMIA PI MEXICO CITY PA APARTADO POSTAL 70-264, MEXICO CITY 04510, MEXICO SN 1405-2059 J9 REV MEX AST ASTR PY 1999 VL 8 BP 131 EP 136 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BP72Z UT WOS:000085992800026 ER PT B AU Hall, L Hung, CK Lin, II AF Hall, L Hung, CK Lin, II BE Callaos, N Nada, N Cherif, A Aveledo, M TI NASA JPL distributed systems technology (DST) object-oriented component approach for software inter-operability and reuse SO WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL 1, PROCEEDINGS: INFORMATION SYSTEMS LA English DT Proceedings Paper CT World Multiconference on Systemics, Cybernetics and Informatics/5th International Conference on Information Systems, Analysis and Synthesis (ISAS 99) CY JUL 31-AUG 04, 1999 CL ORLANDO, FL SP Int Inst Informat & System, IEEE Comp Soc, Venezuela Chapter, World Org System & Cybernet, Int Federat Syst Res, Int Soc Syst Sci, Int Syst Inst, CUST, Int Inst Av Studies Syst Res & Cybernet, Soc Appl Syst Res, Cybernet & Human Knowing, Cent Univ Venezuela, Simon Bolivar Univ DE software reuse; inter-operability; object-oriented; object component software; component-based development; infrastructure; distributed systems; prototypes AB The purpose of this paper is to provide a description of NASA JPL Distributed Systems Technology (DST) Section's object-oriented component approach to open inter-operable systems software development and software reuse. It will address what is meant by the terminology object component software, give an overview of the component-based development approach and how it relates to infrastructure support of software architectures and promotes reuse, enumerate on the benefits of this approach, and give examples of application prototypes demonstrating its usage and advantages. Utilization of the object-oriented component technology approach for system development and software reuse will apply to several areas within JPL, and possibly across other NASA Centers. C1 CALTECH, Jet Prop Lab, Distributed Comp & Syst Engn Grp, Pasadena, CA 91109 USA. RP Hall, L (reprint author), CALTECH, Jet Prop Lab, Distributed Comp & Syst Engn Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU INT INST INFORMATICS & SYSTEMICS PI ORLANDO PA 14269 LORD BARCLAY DR, ORLANDO, FL 32837 USA BN 980-07-5912-3 PY 1999 BP 626 EP 631 PG 6 WC Computer Science, Cybernetics; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BU36X UT WOS:000175784700100 ER PT S AU Petre, R Chen, C Cohen, L Content, D Harms, RJ Mongrard, O Monnelly, G Saha, T Schattenburg, M Serlemitsos, P Zhang, W AF Petre, R Chen, C Cohen, L Content, D Harms, RJ Mongrard, O Monnelly, G Saha, T Schattenburg, M Serlemitsos, P Zhang, W BE Hoover, RB Walker, ABC TI Segmented x-ray mirror development for Constellation-X SO X-RAY OPTICS, INSTRUMENTS, AND MISSIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Optics, Instruments, and Mission II CY JUL 18-20, 1999 CL DENVER, CO SP SPIE DE x-ray optics; Constellation-X ID TELESCOPE AB Segmented mirrors are one of the two approaches being investigated for both the Spectroscopy X-Ray Telescope (SXT) and the Hard X-Ray Telescope (HXT) on Constellation-X. Mirrors based on the grazing incidence foil optics pioneered by GSFC will meet the stringent Constellation-X SXT weight requirement, but the currently achieved resolution falls short of the 15" half-power diameter (HPD) required for Constellation-X. Significant contributions to the blur arise from the figure of individual reflectors and from inaccurate mounting. Only a small contribution to the HPD of the existing mirrors arises from the conical approximation. In this paper, we describe our program for improving the spatial resolution of segmented mirrors to meet the Constellation-X requirement. Our effort incorporates accurately figured replication mandrels, mechanically more robust reflector substrates, high accuracy alignment, and ultimately a transition from conical to curved reflecting surfaces. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Petre, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 13 Z9 13 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3252-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3766 BP 11 EP 21 DI 10.1117/12.363639 PG 11 WC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology SC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology GA BN95G UT WOS:000083637600002 ER PT S AU Content, D Saha, T Petre, R Lyons, JJ Wright, G Zaniewski, J Chan, KW AF Content, D Saha, T Petre, R Lyons, JJ Wright, G Zaniewski, J Chan, KW BE Hoover, RB Walker, ABC TI Superpolishing and precision metrology on a metal mandrel and replicated segments for Constellation-X SO X-RAY OPTICS, INSTRUMENTS, AND MISSIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Optics, Instruments, and Mission II CY JUL 18-20, 1999 CL DENVER, CO SP SPIE DE X-ray optics; superpolishing precision metrology; Constellation-X; power spectral density ID PERFORMANCE; ULTRAVIOLET AB We have superpolished a diamond-turned aluminum mandrel (coated with electroless Ni) to an axial roughness of 0.34 nm rms. The mandrel is made to the Astro-E secondary mirror design for the 81st shell. Precision metrology at 100 mm to submicron scales has established the power spectral density of the mandrel and ultralightweight gold coated replicated segments. Predicted image quality of a set of optimally aligned replicated segments of this and a matching primary is substantially improved as compared to the flight mirrors for Astro-E. This approach using metal mandrels, superpolishing, and replicated ultralightweight foil mirrors, may represent a cost-effective approach to meeting the 15 arcsec half-energy width and weight requirements for the Constellation-X mission. Descriptions of the polishing apparatus, the precision metrology instruments, and the surface data analysis are presented. The general methods described are applicable to precision optics for both normal incidence and grazing incidence optics. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Content, D (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, MC551, Greenbelt, MD 20771 USA. NR 20 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3252-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3766 BP 22 EP 33 DI 10.1117/12.363647 PG 12 WC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology SC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology GA BN95G UT WOS:000083637600003 ER PT S AU Zissa, DE AF Zissa, DE BE Hoover, RB Walker, ABC TI AXAF-I High Resolution Mirror Assembly image model and comparison with x-ray ground-test image SO X-RAY OPTICS, INSTRUMENTS, AND MISSIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Optics, Instruments, and Mission II CY JUL 18-20, 1999 CL DENVER, CO SP SPIE DE AXAF; Chandra X-ray Observatory; CXO; x-ray optics; grazing-incidence optics; image modeling; ray-trace modeling; x-ray scattering ID OPTICS AB The completed High Resolution Mirror Assembly (HRMA) of the Advanced X-ray Astrophysics Facility - imaging (AXAF-I) was tested at the X-ray Calibration Facility (XRCF) at the NASA-Marshall Space Flight Center (MSFC) in 1997. The MSFC image model was developed during the development of AXAF-I (now named Chandra X-ray Observatory). The MSFC model is a detailed ray-trace model of the as-built HRMA optics and the XRCF test conditions. The image encircled-energy distributions from the model are found to generally agree well with XRCF test data and the preliminary Smithsonian Astrophysical Observatory (SAO) model. MSFC model effective-area results generally agree with those of the preliminary SAO model. Preliminary model effective-area results were reported by SAO to be similar to 5-13% above initial XRCF test results. The XRCF test conditions are removed from the MSFC ray-trace model to derive an on-orbit prediction of the HRMA image. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Zissa, DE (reprint author), NASA, George C Marshall Space Flight Ctr, SD73, Huntsville, AL 35812 USA. NR 12 TC 5 Z9 5 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3252-0 J9 P SOC PHOTO-OPT INS PY 1999 VL 3766 BP 36 EP 50 DI 10.1117/12.363656 PG 15 WC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology SC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology GA BN95G UT WOS:000083637600004 ER PT J AU De, S Heaney, PJ Hargraves, RB Vicenzi, EP Taylor, PT AF De, S Heaney, PJ Hargraves, RB Vicenzi, EP Taylor, PT TI Microstructural observations of polycrystalline diamond: a contribution to the carbonade conundrum SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE carbonado; diamond; ultrastructure ID CHICXULUB CRATER; SILICON-CARBIDE; CENTRAL-AFRICA; IMPACT CRATER; MELT ROCK; ORIGIN; DEFORMATION; IRON; INCLUSIONS; PHASES AB The formation mechanism of carbonade, a polycrystalline variety of diamond, remains unresolved. Here we report a microstructural analysis of systematic defects and inclusions in carbonades from Brazil and the Central African Republic (CAR). Transmission electron microscopy (TEM) has revealed the presence of pervasive defect lamellae in both the CAR and Brazilian carbonades that are distinct from planar defects observed in synthetic polycrystalline diamond (PCD). Analyses of included minerals by energy dispersive spectroscopy (EDS) yielded strong evidence for metallic Fe, Ti, and Si, as well as SIC and Fe-Cr alloys, within the diamond matrix. Our results offer strong evidence for a close genetic relationship between Brazilian and Central African carbonades, suggesting formation within a united landmass during the late Archaean, The data do not preclude carbonade nucleation by meteoritic impact, though this issue remains contentious. The role of water in the growth of carbonade merits further exploration. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP De, S (reprint author), Penn State Univ, Dept Geosci, 438 Deike Bldg Off,322-324 Deike Bldg Lab, University Pk, PA 16802 USA. EM barna@geosc.psu.edu RI Taylor, Patrick/D-4707-2012 OI Taylor, Patrick/0000-0002-1212-9384 NR 64 TC 39 Z9 39 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X EI 1385-013X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD DEC 30 PY 1998 VL 164 IS 3-4 BP 421 EP 433 DI 10.1016/S0012-821X(98)00229-5 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 153TB UT WOS:000077847800002 ER PT J AU Shebalin, JV AF Shebalin, JV TI Phase space structure in ideal homogeneous turbulence SO PHYSICS LETTERS A LA English DT Article DE classical ensemble theory; homogeneous turbulence; plasmas; magnetohydrodynamics ID MAGNETOHYDRODYNAMIC TURBULENCE; ABSOLUTE EQUILIBRIUM; BROKEN ERGODICITY AB The phase spaces of finite Fourier representations of ideal, incompressible, homogeneous fluid and magneto-fluid turbulence are discussed. Helical invariance allows the definition of set-theoretic characteristic functions which partition the various ensemble phase spaces into disjoint components. This explicit disjointness explains the previously observed nonergodicity in ideal, incompressible, homogeneous turbulence. (C) 1998 Elsevier Science B.V. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP NASA, Lyndon B Johnson Space Ctr, Mail Code OZ4, Houston, TX 77058 USA. EM j.shebalin@jsc.nasa.gov NR 19 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 EI 1873-2429 J9 PHYS LETT A JI Phys. Lett. A PD DEC 28 PY 1998 VL 250 IS 4-6 BP 319 EP 322 DI 10.1016/S0375-9601(98)00802-0 PG 4 WC Physics, Multidisciplinary SC Physics GA 155GD UT WOS:000077937600014 ER PT J AU Jensen, EJ Ackerman, AS Stevens, DE Toon, OB Minnis, P AF Jensen, EJ Ackerman, AS Stevens, DE Toon, OB Minnis, P TI Spreading and growth of contrails in a sheared environment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB A case study of persistent contrail evolution in a sheared environment is simulated over time-scales of 15-180 min using a large-eddy simulation model with detailed microphysics. Model results are compared to satellite and in situ measurements of persistent contrails from the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) experiment. In simulations with large ambient supersaturations and moderate wind shear, crystals with lengths >200 mu m are generated within 45 min by depositional growth. These crystals fall rapidly, and the contrail horizontal extent increases due to the wind shear. Strong radiative heating (with rates up to 10 K d(-1)) drives a local updraft and lofts the contrail core several hundred meters. The observed rate of contrail spreading and maintenance of optical depths larger than 0.05 can be approximately explained simply by growth and precipitation of ice crystals nucleated during the initial contrail formation if the environmental humidity is very high (relative humidity with respect to ice >125%). This result is consistent with observed high humidities in regions where persistent contrails formed during SUCCESS. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94550 USA. Univ Colorado, LASP, Boulder, CO 80309 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, Ames Res Ctr, MS 245-4, Moffett Field, CA 94035 USA. EM ejensen@sky.arc.nasa.gov; stevens@mothra.lbl.gov; toon@lasp.colorado.edu; p.minnis@larc.nasa.gov RI Ackerman, Andrew/D-4433-2012; Minnis, Patrick/G-1902-2010 OI Ackerman, Andrew/0000-0003-0254-6253; Minnis, Patrick/0000-0002-4733-6148 NR 24 TC 49 Z9 49 U1 0 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 DEC 27 PY 1998 VL 103 IS D24 BP 31557 EP 31567 DI 10.1029/98JD02594 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000004 ER PT J AU Shah, KP Rind, D AF Shah, KP Rind, D TI Comparing upper tropospheric and lower stratospheric temperatures: Microwave sounding unit, radiosonde, COSPAR International Reference Atmosphere, and National Center for Environmental Prediction National Center for Atmospheric Research reanalysis monthly mean climatologies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; DEEP-LAYER TEMPERATURES; CLIMATE-CHANGE; VALIDATION; PRECISION; MSU; PARAMETERS; TRANSPORT; ANOMALIES; SPECTRUM AB Climate-modeling groups are having to assess their models' temperatures at high, thinly observed altitudes in order to investigate near-tropopause forcings with confidence. To support such analyses, the microwave sounding unit (MSU), GFDL/Oort radiosonde, COSPAR International Reference Atmosphere (CIRA), and new 13-year National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis Project climatologies are intercompared herein in terms of their monthly mean microwave brightness temperatures T-b. In the lower stratosphere these climatologies agree extremely well. Small differences between NCEP/NCAR and MSU T-b centered at about 80 mbar amount to less than or equal to 2 K year round across the tropics and less than or equal to 5 K in southern winter polar latitudes. Artificial land-ocean outlines less than or equal to 2 K do appear in maps of the NCEP/NCAR lower stratospheric T-b between 30 degrees S and 30 degrees N. This NCEP/NCAR land-ocean T-b distinction may be due to sparseness of inputed radiosonde data at lower stratospheric heights not compensated for by satellite retrievals in the NCEP/NCAR assimilation process. In the upper troposphere, good agreement again occurs between the GFDL radiosonde, the CIRA, and the NCEP/NCAR reanalysis T-b. However, the experimental MSU channel 3R climatology has markedly cooler upper tropospheric T-b. Coolness peaks at over 6 K across low latitudes and diminishes to a few kelvins at polar latitudes with little seasonal dependence. The cool bias of the MSU channel 3R is likely due to a combination of channel 3 receiver drift and limb-darkening problems. Latitudinal correction terms are suggested for this experimental, but valuable, MSU product based on comparisons with calculated NCEP/NCAR reanalysis T-b. C1 Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10024 USA. RP Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10024 USA. EM kshah@giss.nasa.gov; kps9@columbia.edu NR 46 TC 7 Z9 7 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 DEC 27 PY 1998 VL 103 IS D24 BP 31569 EP 31591 DI 10.1029/98JD02452 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000005 ER PT J AU Kratz, DP Chou, MD Yan, MMH Ho, CH AF Kratz, DP Chou, MD Yan, MMH Ho, CH TI Minor trace gas radiative forcing calculations using the k distribution method with one-parameter scaling SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRANSMISSION FUNCTIONS; COOLING RATES; CO2; ABSORPTION; ATMOSPHERES; CFC-11; CIRRUS; BANDS AB The k distribution method with one-parameter pressure and temperature scaling, first developed for water vapor, has now been applied to the minor trace gas (N2O, CH4, CFCs, and two minor bands of CO2) absorption in the infrared window region (800-1380 cm(-1)). The derivation of the k distributions is based upon an exponential sum fitting to the monochromatically calculated transmission functions at a predetermined reference pressure and temperature. For nonhomogeneous path lengths, one-parameter scaling is utilized in conjunction with the k distribution method. To determine the accuracies of the k distribution method as compared to the monochromatic calculations, fluxes and cooling rates are calculated for a wide variety of atmospheric conditions. For the entire 800-1380 cm(-1) spectral range the effect of the minor trace gases on the fluxes calculated using the k distribution method is within 2.3% of the monochromatic method. In addition to being accurate, this method is computationally very fast. When implemented into the Goddard EOS general circulation model, the computing time for the longwave flux calculations is increased by only 20% despite the inclusion of the minor trace gas absorption bands. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Seoul Natl Univ, Dept Atmospher Sci, Seoul 151742, South Korea. Sci Syst & Applicat Inc, Seabrook, MD 20706 USA. RP NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. EM d.p.kratz@larc.nasa.gov; chou@climate.gsfc.nasa.gov; yan@climate.gsfc.nasa.gov; hoch@climate.snu.ac.kr RI Ho, Chang-Hoi/H-8354-2015 NR 25 TC 29 Z9 29 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 DEC 27 PY 1998 VL 103 IS D24 BP 31647 EP 31656 DI 10.1029/1998JD200009 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000010 ER PT J AU Clark, HL Harwood, RS Mote, PW Read, WG AF Clark, HL Harwood, RS Mote, PW Read, WG TI Variability of water vapor in the tropical upper troposphere as measured by the Microwave Limb Sounder on UARS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID 40-50 DAY OSCILLATION; EL-NINO; INTRASEASONAL OSCILLATION; CIRCULATION ANOMALIES; RELATIVE-HUMIDITY; PACIFIC OCEANS; CONVECTION; SATELLITE; TEMPERATURE; COOLNESS AB The Microwave Limb Sounder (MLS), an instrument on the Upper Atmosphere Research Satellite (UARS), measures water vapor in the upper troposphere, with best sensitivity at the standard UARS level at 215 hPa. In this paper, we analyze the MLS observations with a view to characterizing the temporal and zonal variations of upper tropospheric water vapor between 20 degrees N and 20 degrees S. Time series of water vapor throughout the tropics show a strong annual cycle with maximum amplitude at 20 degrees N and 90 degrees E. An intraseasonal cycle with a period of 30-85 days is evident over the Western Pacific at latitudes from 10 degrees N to 20 degrees S. The cycle is associated with eastward propagating disturbances of zonal wavenumbers 1-2, suggesting that this intraseasonal cycle is related to the Madden-Julian oscillation. C1 Univ Edinburgh, Dept Meteorol, Edinburgh EH8 3JZ, Midlothian, Scotland. NW Res Associates Inc, Bellevue, WA 98009 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Edinburgh, Dept Meteorol, W Mains Rd, Edinburgh EH8 3JZ, Midlothian, Scotland. EM H.Clark@ed.ac.uk; r.harwood@ed.ac.uk; mote@nwra.com; bill@mls.jpl.nasa.gov NR 38 TC 14 Z9 15 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 DEC 27 PY 1998 VL 103 IS D24 BP 31695 EP 31707 DI 10.1029/98JD02702 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000014 ER PT J AU Kaufman, YJ Hobbs, PV Kirchhoff, VWJH Artaxo, P Remer, LA Holben, BN King, MD Ward, DE Prins, EM Longo, KM Mattos, LF Nobre, CA Spinhirne, JD Ji, Q Thompson, AM Gleason, JF Christopher, SA Tsay, SC AF Kaufman, YJ Hobbs, PV Kirchhoff, VWJH Artaxo, P Remer, LA Holben, BN King, MD Ward, DE Prins, EM Longo, KM Mattos, LF Nobre, CA Spinhirne, JD Ji, Q Thompson, AM Gleason, JF Christopher, SA Tsay, SC TI Smoke, Clouds, and Radiation - Brazil (SCAR-B) experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID TROPICAL SOUTH-ATLANTIC; ATMOSPHERIC CHEMISTRY; SPECTRAL RADIANCES; SATELLITE IMAGERY; SULFATE AEROSOLS; FIELD EXPERIMENT; LAND SURFACES; SAVANNA FIRES; DRY SEASON; BIOMASS AB The Smoke, Clouds, and Radiation-Brazil (SCAR-B) field project took place in the Brazilian Amazon and cerrado regions in August-September 1995 as a collaboration between Brazilian and American scientists. SCAR-B, a comprehensive experiment to study biomass burning, emphasized measurements of surface biomass, fires, smoke aerosol and trace gases, clouds, and radiation, their climatic effects, and remote sensing from aircraft and satellites. It included aircraft and ground-based in situ measurements of smoke emission factors and the compositions, sizes, and optical properties of the smoke particles; studies of the formation of ozone; the transport and evolution of smoke; and smoke interactions with water vapor and clouds. This overview paper introduces SCAR-B and summarizes some of the main results obtained so far. (1) Fires: measurements of the size distribution of fires, using the 50 m resolution MODIS Airborne Simulator, show that most of the fires are small (e.g., 0.005 km(2)), but the satellite sensors (e.g., AVHRR and MODIS with 1 km resolution) can detect fires in Brazil which are responsible for 60-85% of the burned biomass; (2) Aerosol: smoke particles emitted from fires increase their radius by as much as 60% during their first three days in the atmosphere due to condensation and coagulation, reaching a mass median radius of 0.13-0.17 mu m; (3) Radiative forcing: estimates of the globally averaged direct radiative forcing due to smoke worldwide, based on the properties of smoke measured in SCAR-B (-0.1 to -0.3 W m(-2)), are smaller than previously modeled due to a lower single-scattering albedo (0.8 to 0.9), smaller scattering efficiency (3 m(2) g(-1) at 550 nm), and low humidification factor; and (4) Effect on clouds: a good relationship was found between cloud condensation nuclei and smoke volume concentrations, thus an increase in the smoke emission is expected to affect cloud properties. In SCAR-B, new techniques were developed for deriving the absorption and refractive index of smoke from ground-based remote sensing. Future spaceborne radiometers (e.g., MODIS on the Earth Observing System), simulated on aircraft, proved to be very useful for monitoring smoke properties, surface properties, and the impacts of smoke on radiation and climate. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, Brazil. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Inst Nacl Pesquisas Espaciais, BR-12201970 Sao Jose Dos Campos, Brazil. NOAA, NESDIS, ORA, Madison, WI 53706 USA. US Forest Serv, Intermt Res Stn, Missoula, MT 59807 USA. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, Mail Code 913, Greenbelt, MD 20771 USA. EM kaufman@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011; Christopher, Sundar/E-6781-2011; Gleason, James/E-1421-2012; Tsay, Si-Chee/J-1147-2014; Artaxo, Paulo/E-8874-2010; Thompson, Anne /C-3649-2014 OI King, Michael/0000-0003-2645-7298; Artaxo, Paulo/0000-0001-7754-3036; Thompson, Anne /0000-0002-7829-0920 NR 102 TC 216 Z9 219 U1 2 U2 35 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 DEC 27 PY 1998 VL 103 IS D24 BP 31783 EP 31808 DI 10.1029/98JD02281 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000021 ER PT J AU Echalar, F Artaxo, P Martins, JV Yamasoe, M Gerab, F Maenhaut, W Holben, B AF Echalar, F Artaxo, P Martins, JV Yamasoe, M Gerab, F Maenhaut, W Holben, B TI Long-term monitoring of atmospheric aerosols in the Amazon Basin: Source identification and apportionment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRACE-ELEMENTS; TROPICAL FOREST; NUCLEPORE FILTERS; RECEPTOR MODELS; EMISSIONS; PARTICLES; BRAZIL; SULFUR; SIZE; DISTRIBUTIONS AB Continuous sampling of atmospheric aerosols was carried out at mio different sites in the Amazon Basin: Cuiaba (16 degrees S, 56 degrees W), since July 1990, and Alta Floresta (09 degrees S, 56 degrees W), since August 1992. Aerosols were collected on polycarbonate filters mounted in stacked filter units (SFU). Particle-induced X ray emission (PIXE) was used to measure concentrations of up to 26 elements (Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Zr, Au, and Pb). Black carbon (BC) and gravimetric mass analyses were also performed. Inhalable particle ground concentrations showed a marked seasonality, with maxima of more than 100 mu g m(-3) in the dry season. The high aerosol optical thickness (AOT) values in this period (up to 4.0 at lambda = 0.440 mu m) indicate that the whole air column has a significant aerosol load. Three main types of aerosol sources were identified: biomass burning, natural biogenic emissions, and soil dust resuspension. During the dry season the fine mode aerosol originated predominantly from biomass burning emissions (they were responsible for about 73% of fine aerosol mass), while the coarse mode was dominated by soil dust particles (50 to 60% of the aerosol mass). Crustal elements exhibited a unimodal coarse mode size distribution, while the pyrogenic elements showed a clear submicrometer mode. Black carbon had a submicrometer mode centered at 0.175 mu m. During the wet season, biogenic aerosols were the dominant particle type and also the main source of atmospheric P in the region. C1 Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. Univ Ghent, Inst Nucl Sci, B-9000 Ghent, Belgium. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Sao Paulo, Inst Fis, Caixa Postal 66318, BR-05315970 Sao Paulo, Brazil. EM artaxo@if.usp.br; maenhaut@inwchem.rug.ac.be; brent@kratmos.gsfc.nasa.gov RI Yamasoe, Marcia/L-3667-2013; Maenhaut, Willy/M-3091-2013; Artaxo, Paulo/E-8874-2010 OI Yamasoe, Marcia/0000-0003-3066-9146; Maenhaut, Willy/0000-0002-4715-4627; Artaxo, Paulo/0000-0001-7754-3036 NR 73 TC 60 Z9 61 U1 0 U2 11 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 DEC 27 PY 1998 VL 103 IS D24 BP 31849 EP 31864 DI 10.1029/98JD01749 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000025 ER PT J AU Eck, TF Holben, BN Slutsker, I Setzer, A AF Eck, TF Holben, BN Slutsker, I Setzer, A TI Measurements of irradiance attenuation and estimation of aerosol single scattering albedo for biomass burning aerosols in Amazonia SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OPTICAL-PROPERTIES; SATELLITE DATA; SURFACE; SMOKE; DEFORESTATION; ABSORPTION; RADIATION; BASIN AB Investigation of the effects of biomass burning aerosols on the surface irradiance were conducted as a part of the Smoke, Clouds, and Radiation - Brazil (SCAR-B) experiment during August - September 1995. Measurements of broadband and spectral irradiance, in conjuction with measurements of aerosol physical and optical properties (optical depth, phase function, and size distribution) were made under varying conditions of aerosol loading during the SCAR-B field campaign. Estimates of aerosol single scattering albedo (omega(o)) were made from matching of the measured irradiance values to the model computed irradiances by varying omega(o), for observations made under cloudless conditions. Values of omega(o), at approximately 550 nm, estimated from this technique using broadband 400-700 nm irradiance measurements, ranged from approximately 0.82 to 0.94 for the dates and times of these SCAR-B measurements. Utilizing spectral irradiance data, the model retrieved values of omega(o) decreased with increasing wavelength, with the change of omega(o) as a function of wavelength differing on different days. Reductions in photosynthetically active radiation (PAR; 400-700 MI) incident at the surface were computed to range from about 20 to 45% compared to background aerosol conditions for the 2 month biomass burning season at several locations in the southern Amazon Basin. These large reductions in incident PAR at the surface due to the heavy aerosol loadings could have implications for primary production of sensitive ecosystems. In addition, reductions of total incident solar radiation from aerosol direct radiative effects may have significant impact on reducing surface heating and increasing aerosol layer heating from absorption. C1 NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Inst Nacl Pesquisas Espaciais, BR-12201970 Sao Jose Dos Campos, Brazil. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Code 923, Greenbelt, MD 20771 USA. EM tom@spamer.gsfc.nasa.gov; brent@spamer.gsfc.nasa.gov; ilya@spamer.gsfc.nasa.gov; asetzer@ltid.inpe.br RI ECK, THOMAS/D-7407-2012 NR 33 TC 105 Z9 106 U1 0 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 DEC 27 PY 1998 VL 103 IS D24 BP 31865 EP 31878 DI 10.1029/98JD00399 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000026 ER PT J AU Remer, LA Kaufman, YJ Holben, BN Thompson, AM McNamara, D AF Remer, LA Kaufman, YJ Holben, BN Thompson, AM McNamara, D TI Biomass burning aerosol size distribution and modeled optical properties SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL SOUTH-ATLANTIC; AIRBORNE; SMOKE; POLLUTION; ALBEDO; PARTICLES; RADIATION; CLOUDS AB Satellite remote sensing of smoke aerosol and estimates of aerosol forcing of climate require knowledge of the aerosol optical properties. A smoke aerosol physical and optical model is developed from a database of over 800 volume size distributions inverted from sky radiance data measured by the AERONET radiometer network in Brazil over a 3-year period. The model represents total column, ambient conditions during the burning season in the Amazon Basin and cerrado region of Brazil. The mean volume size distributions are bimodal and can be represented by two lognormals. Accumulation mode modal radius is 0.13 +/- 0.02 mu m with sigma = 0.60 +/- 0.04, and coarse-mode modal radius ranges from 6 to 40 mu m, with a mean of 11.5 mu m and sigma = 1.26 +/- 0.23. The volume of each mode varies with optical thickness, causing the ratio of accumulation mode and coarse mode to vary as well, but the effect on the optical properties is negligible. Refractive index is taken to be 1.43-0.0035i, and single scattering albedo is assumed to be 0.90, which is modeled with an external mixing of black carbon. The optical properties in the visible are dominated by the accumulation mode. Accumulation mode characteristics do not vary from year to year, from forest to cerrado region, with optical thickness or with precipitable water vapor. At one test location, accumulation mode characteristics do vary with air mass trajectory origin. The model is tested with independent data and can accurately predict the scattering phase function and path radiance in the backscattering direction that determines remote sensing properties and is responsible for scattering sunlight back to space. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, 913, Greenbelt, MD 20771 USA. EM remer@climate.gsfc.nasa.gov RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 46 TC 95 Z9 99 U1 0 U2 9 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 DEC 27 PY 1998 VL 103 IS D24 BP 31879 EP 31891 DI 10.1029/98JD00271 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000027 ER PT J AU Yamasoe, MA Kaufman, YJ Dubovik, O Remer, LA Holben, BN Artaxo, P AF Yamasoe, MA Kaufman, YJ Dubovik, O Remer, LA Holben, BN Artaxo, P TI Retrieval of the real part of the refractive index of smoke particles from Sun/sky measurements during SCAR-B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SCATTERING PHASE FUNCTION; VAPOR COLUMN ABUNDANCE; LABORATORY MEASUREMENTS; OPTICAL-PROPERTIES; AEROSOL-PARTICLES; BIOMASS; DISTRIBUTIONS; ATMOSPHERE; FIRE; APPROXIMATION AB A method is used to retrieve the real part of the refractive index of ambient aerosol particles in the entire vertical column using ground-based measurements of the angular dependence of the spectral sky radiance. The method is applied to smoke aerosol particles using spectral Sun/sky data measured by the AERONET (Aerosol Robotic Network) radiometers in Cuiaba, Brazil, during the SCAR-B (Smoke, Clouds, and Radiation-Brazil) experiment in 1995. The refractive index is retrieved from comparison between measurements taken in the solar almucantar and calculations using Mie theory. First the aerosol size distribution is derived from sky radiance at scattering angles less then 40 degrees, then the refractive index is derived from sky radiances for angles of 20 degrees-100 degrees, Simulations and sensitivity studies are presented showing that the expected error is +/-0.03. Application of the method to the Cuiaba region, which is dominated by smoke from cerrado vegetation burning, resulted in a mean value for the real part of the index of refraction of 1.53 +/- 0.04, 1.55 +/- 0.04, 1.59 +/- 0.02, and 1.58 +/- 0.01, respectively, for wavelengths of 438, 670, 870, and 1020 nm, Though we do not have independent verification of the results, we tested the effect of water vapor on the refractive index. The low humidification factors measured in Brazil and the lack of high relative humidities suggested a small effect of water vapor. In fact, as expected, a nonsignificant correlation was observed between the retrieved values of refractive index and total precipitable water vapor. Application to aerosol in the eastern United States (not reported here), with high humidity and high humidification factors, did show a strong reduction of the refractive index with increase of the total precipitable water vapor, thus generating confidence in the methodology. C1 Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Univ Sao Paulo, Inst Fis, Caixa Postal 66318, BR-05315970 Sao Paulo, Brazil. EM akemi@if.usp.br RI Dubovik, Oleg/A-8235-2009; Yamasoe, Marcia/L-3667-2013; Artaxo, Paulo/E-8874-2010 OI Dubovik, Oleg/0000-0003-3482-6460; Yamasoe, Marcia/0000-0003-3066-9146; Artaxo, Paulo/0000-0001-7754-3036 NR 46 TC 43 Z9 45 U1 0 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 DEC 27 PY 1998 VL 103 IS D24 BP 31893 EP 31902 DI 10.1029/98JD01211 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000028 ER PT J AU Dubovik, O Holben, BN Kaufman, YJ Yamasoe, M Smirnov, A Tanre, D Slutsker, I AF Dubovik, O Holben, BN Kaufman, YJ Yamasoe, M Smirnov, A Tanre, D Slutsker, I TI Single-scattering albedo of smoke retrieved from the sky radiance and solar transmittance measured from ground SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SIZE DISTRIBUTION; BRIGHTNESS MEASUREMENTS; TROPOSPHERIC AEROSOLS; REFRACTIVE-INDEX; PHASE FUNCTION; PARTICLES; ABSORPTION; ATMOSPHERE AB A method of aerosol single-scattering albedo retrieval from diffuse radiance measured in the solar almucantar and direct solar measurements is proposed, The aerosol scattering optical thickness is derived from the diffuse radiance by applying a radiative transfer model driven by aerosol microstructure parameters and Mie theory. To improve the accuracy of the scattering optical thickness, the inversion results are acceptable only if the radiance is measured across the total almucantar and is accurately fitted by a theoretical model. The aerosol is assumed as an external mixture of purely scattering particles and soot particles, with the soot approximated as a pure absorber. The criterion for the acceptance of fit is determined from the analysis of the effects of random and systematic errors on the single-scattering albedo retrieval. The method was applied to measurements conducted during the Smoke, Clouds, and Radiation - Brazil (SCAR-B) campaign in August and September 1995. Aerosol radiance data were extensively collected by the Aerosol Robotic Network (AERONET) of ground-based Sun/sky radiometers. The analysis focuses on the studies of the time variability of the biomass burning aerosol in the local Cuiaba area, supplemented by measurements collected in Cuiaba in 1993-1994. The results show reasonable ranges of the aerosol single-scattering albedo variability (for example, single-scattering albedo averages 0.87 +/-0.08 at 670 nm). The spectral dependence of the single-scattering albedo has both tendencies: decreasing and increasing with wavelength. The potential reasons causing different spectral behavior are analyzed theoretically. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. UST Lille, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. RP NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. EM dubovik@spamer.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Yamasoe, Marcia/L-3667-2013 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Yamasoe, Marcia/0000-0003-3066-9146 NR 37 TC 76 Z9 79 U1 2 U2 12 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 DEC 27 PY 1998 VL 103 IS D24 BP 31903 EP 31923 DI 10.1029/98JD02276 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000029 ER PT J AU Ross, JL Hobbs, PV Holben, B AF Ross, JL Hobbs, PV Holben, B TI Radiative characteristics of regional hazes dominated by smoke from biomass burning in Brazil: Closure tests and direct radiative forcing SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL SOUTH-ATLANTIC; ATMOSPHERIC AEROSOL; OPTICAL-PROPERTIES; SPECTROMETER PROBE; CROSS-SECTION; AMAZON BASIN; ABSORPTION; SCATTERING; DEPOSITION; AIRBORNE AB Ground-based Sun photometer measurements, and airborne measurements of the physical and optical properties of regional hazes dominated by smoke from biomass burning in Brazil, are used for aerosol radiative vertical column and local radiative closure tests. Optical depths at midvisible wavelengths of up to 2.5 measured by two independent methods (ground-based Sun photometers and airborne measurements of the vertical profiles of aerosol optical extinction to the top of the smoke layer) agreed, on average, to within similar to 20%. Local aerosol closure tests were carried out using in situ measurements of particle size distributions as inputs to a computational model of the aerosol. Calculated aerosol masses, aerosol absorption and scattering coefficients, and the amounts of solar radiation backscattered by the aerosol were generally within 25% of the measured values. The computational model was used to calculate a broader range of radiative transfer parameters, including aerosol mass scattering and absorption efficiencies, the asymmetry parameter, and upscatter fraction, across the solar spectrum. Regional values of direct aerosol radiative forcing produced by smoke aerosol in the cerrado and primary forest areas of Brazil are derived using the radiative transfer parameters as inputs to a radiative transfer model. The resulting net direct radiative forcing can result in either a cooling or a heating depending on the underlying surface albedo. Over a typical tropical forest the change in the daily average net shortwave flux per unit optical depth (at a wavelength of 550 nm) is -20 +/- 7 W m(-2) (where a negative value indicates cooling). Over the cerrado the forcing is -8 +/- 9 W m(-2), while over a dark surface, such as the ocean, the forcing is -26 +/- 6 W m(-2). Over a reflective surface, such as a desert, we calculate a positive (heating) forcing of +25 +/- 12 W m(-2). C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Washington, Dept Atmospher Sci, Box 351640, Seattle, WA 98195 USA. EM John.Ross2@PSS.Boeing.com; phobbs@atmos.washington.edu; brent@spamer.gsfc.nasa.gov NR 37 TC 81 Z9 83 U1 0 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 DEC 27 PY 1998 VL 103 IS D24 BP 31925 EP 31941 DI 10.1029/97JD03677 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000030 ER PT J AU Tsay, SC King, MD Arnold, GT Li, JY AF Tsay, SC King, MD Arnold, GT Li, JY TI Airborne spectral measurements of surface anisotropy during SCAR-B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIDIRECTIONAL REFLECTANCE; HEMISPHERICAL REFLECTANCE; VEGETATED SURFACES; EOS-MODIS; ALBEDO; NADIR; CANOPIES AB During the Smoke, Clouds, and Radiation-Brazil (SCAR-B) deployment, angular distributions of spectral reflectance for vegetated surfaces and smoke layers were measured using the scanning cloud absorption radiometer (CAR) mounted on the University of Washington C-131A research aircraft. The CAR contains 13 narrowband spectral channels between 0.3 and 2.3 mu m with a 190 degrees scan aperture (5 degrees before zenith to 5 degrees past nadir) and 1 degrees instantaneous field of view. The bidirectional reflectance is obtained by flying a clockwise circular orbit above the surface, resulting in a ground track similar to 3 km in diameter within about 2 min. Although the CAR measurements are contaminated by minor atmospheric effects, results show distinct spectral characteristics for various types of surfaces. Spectral bidirectional reflectances of three simple and well-defined surfaces are presented: cerrado (August 18, 1995) and dense forest (August 25, 1995), both measured in Brazil under nearly clear-sky conditions, and thick smoke layers over dense forest (September 6 and 11, 1995). The bidirectional reflectances of cerrado and dense forest revealed fairly symmetric patterns along the principal plane, with varying maximal strengths and widths spectrally in the backscattering direction. In the shortwave-infrared region the aerosol effect is very small due to low spectral optical depth. Also, these backscattering maxima can be seen on the bidirectional reflectance of smoke layer over dense forest. These detailed measurements of the angular distribution of spectral reflectance can be parameterized by a few independent variables and utilized to retrieve either surface characteristics or aerosol microphysical and optical properties (e.g., size distribution and single-scattering parameters), if proper physical and radiation models are used. The spectral-hemispherical albedo of these surfaces is obtained directly by integrating all angular measurements and is compared with the measured nadir reflectance. Using CAR nadir reflectance as a surrogate for spectral-hemispherical albedo can cause albedos to be underestimated by 10-60%, depending on solar zenith angle. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Applicat Corp, Vienna, VA USA. RP NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. EM tsay@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011; Tsay, Si-Chee/J-1147-2014 OI King, Michael/0000-0003-2645-7298; NR 24 TC 28 Z9 31 U1 0 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 DEC 27 PY 1998 VL 103 IS D24 BP 31943 EP 31953 DI 10.1029/98JD01167 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000031 ER PT J AU Kaufman, YJ Kleidman, RG King, MD AF Kaufman, YJ Kleidman, RG King, MD TI SCAR-B fires in the tropics: Properties and remote sensing from EOS-MODIS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AFRICAN SAVANNA ECOSYSTEMS; BIOMASS; RESOLUTION; CO AB Two moderate resolution imaging spectroradiometer (MODIS) instruments are planned for launch in 1999 and 2000 on the NASA Earth Observing System (EOS) AM-1 and EOS PM-1 satellites. The MODIS instrument will sense fires with designated 3.9 and 11 mu m channels that saturate at high temperatures (450 and 400 K, respectively). MODIS data will be used to detect fires, to estimate the rate of emission of radiative energy from the fire, and to estimate the fraction of biomass burned in the smoldering phase. The rate of emission of radiative energy is a measure of the rate of combustion of biomass in the fires. In the Smoke, Clouds, and Radiation-Brazil (SCAR-B) experiment the NASA ER-2 aircraft flew the MODIS airborne simulator (MAS) to measure the fire thermal and mid-IR signature with a 50 m spatial resolution. These data are used to observe the thermal properties and sizes of fires in the cerrado grassland and Amazon forests of Brazil and to simulate the performance of the MODIS 1 km resolution fire observations. Although some fires saturated the MAS 3.9 mu m channel, all the fires were well within the MODIS instrument saturation levels. Analysis of MAS data over different ecosystems, shows that the fire size varied from single MAS pixels (50 x 50 m) to over 1 km(2). The 1 x 1 km resolution MODIS instrument can observe only 30-40% of these fires, but the observed fires are responsible for 80 to nearly 100% of the emitted radiative energy and therefore for 80 to 100% of the rate of biomass burning in the region. The rate of emission of radiative energy from the fires correlated very well with the formation of fire burn scars (correlation coefficient = 0.97). This new remotely sensed quantity should be useful in regional estimates of biomass consumption. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, Sci Syst & Applicat Inc, Code 913, Greenbelt, MD 20771 USA. EM kaufman@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011 OI King, Michael/0000-0003-2645-7298 NR 15 TC 52 Z9 56 U1 2 U2 6 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 DEC 27 PY 1998 VL 103 IS D24 BP 31955 EP 31968 DI 10.1029/98JD02460 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000032 ER PT J AU Gleason, JF Hsu, NC Torres, O AF Gleason, JF Hsu, NC Torres, O TI Biomass burning smoke measured using backscattered ultraviolet radiation: SCAR-B and Brazilian smoke interannual variability SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AEROSOLS; AMAZON AB A recently developed method for monitoring biomass burning smoke from space has been applied to measurements over Brazil. Long-term measurements of aerosol index measured from space by a series of satellites show the interannual variability of smoke-covered areas over Brazil. Using a newly developed algorithm, the aerosol index has been inverted into aerosol optical depth values. Coincident ground-based Sun photometer aerosol optical thickness measurements are used to validate this inversion. The interannual variability of the area covered by smoke of varying intensity is described over the period 1978 to 1995. The results show that 1995, the year of the Smoke, Clouds, and Radiation-Brazil (SCAR-B) mission, was similar to recent years for overall smoke area, but the area covered by heavier smoke was larger than other years in the data record. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hughes STX, Lanham, MD 20706 USA. RP NASA, Goddard Space Flight Ctr, Mail Code 916, Greenbelt, MD 20771 USA. EM gleason@redwind.gsfc.nasa.gov RI Gleason, James/E-1421-2012; Hsu, N. Christina/H-3420-2013; Torres, Omar/G-4929-2013 NR 16 TC 27 Z9 27 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 DEC 27 PY 1998 VL 103 IS D24 BP 31969 EP 31978 DI 10.1029/98JD00160 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000033 ER PT J AU Chu, DA Kaufman, YJ Remer, LA Holben, BN AF Chu, DA Kaufman, YJ Remer, LA Holben, BN TI Remote sensing of smoke from MODIS airborne simulator during the SCAR-B experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR; SATELLITE IMAGERY; GREENHOUSE GASES; RELATIVE ROLES; AEROSOL; CLOUD; SPECTROMETER; REFLECTANCE; ALGORITHM; LAND AB MODIS (moderate resolution imaging spectroradiometer) airborne simulator (MAS) data acquired during the SCAR-B (Smoke, Clouds, and Radiation-Brazil) experiment provide a test bed to evaluate aerosol retrievals for MODIS measurements over land. The SCAR-B MAS data covered forest and cerrado regions with varying smoke concentration as a result of fires in August-September, 1995. Excellent agreement is obtained by comparing the retrieved aerosol optical thickness from the MAS data with AERONET (Aerosol Robotic Network) ground-based Sun photometer observations. The evaluation of MODIS aerosol algorithm was performed for a range of smoke optical thickness from 0.1 to 2 at 0.66 mu m wavelength over cerrado and forest sites. All the retrieved values of optical thickness are found within the anticipated retrieval errors of Delta tau = +/-0.05+/-0.2 tau. This confirms for smoke aerosol the validity of the MODIS algorithms and the use of the new dynamic aerosol models in this algorithm (the algorithm was already validated previously for urban/industrial aerosol). The retrieved optical thickness is found to be very sensitive to the assumed value of the single-scattering albedo but not sensitive to the aerosol refractive index (real part). The single-scattering albedo of 0.90 suggested in the aerosol model yields the best results. Test of the MODIS use of a grid box of 10 x 10 km in the aerosol algorithm shows that the standard deviation of the retrieved aerosol should generally not be more than 10% of the average value for a large range of optical thickness values from 0.2 to 2.0, close and far from fires. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 913, Greenbelt, MD 20771 USA. EM achu@climate.gsfc.nasa.gov; kaufman@climate.gsfc.nasa.gov; remer@climate.gsfc.nasa.gov; holben@spamer.gsfc.nasa.gov NR 37 TC 51 Z9 53 U1 2 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 DEC 27 PY 1998 VL 103 IS D24 BP 31979 EP 31987 DI 10.1029/98JD01148 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000034 ER PT J AU King, MD Tsay, SC Ackerman, SA Larsen, NF AF King, MD Tsay, SC Ackerman, SA Larsen, NF TI Discriminating heavy aerosol, clouds, and fires during SCAR-B: Application of airborne multispectral MAS data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR; SPECTROMETER; RADIANCES; MODIS AB A multispectral scanning spectrometer was used to obtain measurements of the reflection function and brightness temperature of smoke, clouds, and terrestrial surfaces at 50 discrete wavelengths between 0.55 and 14.2 mu m. These observations were obtained from the NASA ER-2 aircraft as part of the Smoke, Clouds, and Radiation-Brazil (SCAR-B) campaign, conducted over a 1500 x 1500 km region of cerrado and rain forest throughout Brazil between August 16 and September. 1995. Multispectral images of the reflection function and brightness temperature in 10 distinct bands of the MODIS airborne simulator (MAS) were used to derive a confidence in clear sky (or alternatively the probability of cloud), shadow, fire: and heavy aerosol, In addition to multispectral imagery, monostatic lidar data were obtained along the nadir ground track of the aircraft and used to assess the accuracy of the cloud mask results. This analysis shows that the cloud and aerosol mask being developed for operational use on the moderate-resolution imaging spectroradiometer (MODIS), and tested using MAS data in Brazil, is quite capable of separating cloud, aerosol, shadow, and fires during daytime conditions over land. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99701 USA. RP NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 900, Greenbelt, MD 20771 USA. EM king@climate.gsfc.nasa.gov RI King, Michael/C-7153-2011; Ackerman, Steven/G-1640-2011; Tsay, Si-Chee/J-1147-2014 OI King, Michael/0000-0003-2645-7298; Ackerman, Steven/0000-0002-4476-0269; NR 17 TC 17 Z9 17 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 DEC 27 PY 1998 VL 103 IS D24 BP 31989 EP 31999 DI 10.1029/98JD01043 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000035 ER PT J AU Reid, JS Hobbs, PV Liousse, C Martins, JV Weiss, RE Eck, TF AF Reid, JS Hobbs, PV Liousse, C Martins, JV Weiss, RE Eck, TF TI Comparisons of techniques for measuring shortwave absorption and black carbon content of aerosols from biomass burning in Brazil SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTEGRATING SPHERE TECHNIQUES; THERMAL CHARACTERIZATION; ATMOSPHERIC AEROSOL; OPTICAL-PROPERTIES; ELEMENTAL CARBON; COEFFICIENT; FILTERS; SMOKE; PARTICULATE; PARTICLES AB Six methods for measuring the shortwave absorption and/or black carbon (BC) content of aerosols from biomass burning were compared during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) experiment. The methods were the optical extinction cell (OEC), integrating plate (IP), optical reflectance (OR), particle soot/absorption photometer (PSAP), thermal evolution (TE), and remote sensing (RS). Comparisons were made for individual smoke plumes and for regional hazes dominated by smoke. Taking the OEC as a primary standard, measurements of the absorption coefficient (sigma(a)) showed that the OR method had the lowest uncertainty (17%) in sigma(a). The other optical methods had uncertainties ranging from 20 to 40%. However, with sufficient sample size, the values of sigma(a) derived from the optical methods converged to within 20% of each other. For biomass burning aerosols in regional hazes over Brazil, this led to systematic differences of +/-0.02 in the values of the single-scattering albedo derived from the various in situ techniques. It was found also that the BC content of the aerosol and sigma(a) were poorly correlated. This is likely due to a large uncertainty in the BC content of the aerosol measured by TE, and/or a high variability in the mass absorption efficiency of BC in biomass burning aerosol. Hence there is a high uncertainty in inferring sigma(a) from the BC content of smoke aerosol. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. CEA, CNRS, Ctr Faibles Radioact, Lab Mixte, F-91198 Gif Sur Yvette, France. Univ Sao Paulo, Inst Fis, BR-05508 Sao Paulo, Brazil. Radiance Res, Seattle, WA 98177 USA. NASA, Goddard Space Flight Ctr, Hughes STX Corp, Greenbelt, MD 20771 USA. RP Univ Washington, Dept Atmospher Sci, Box 35160, Seattle, WA 98195 USA. EM reid@atmos.washington.edu; phobbs@atmos.washington.edu; cachier@eole.cfr.cnrsig.fr; vanderlei@if.usp.br; radiance@cmc.net; teck@ltpsun.gsfc.nasa.gov RI ECK, THOMAS/D-7407-2012; Reid, Jeffrey/B-7633-2014 OI Reid, Jeffrey/0000-0002-5147-7955 NR 48 TC 81 Z9 82 U1 1 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 DEC 27 PY 1998 VL 103 IS D24 BP 32031 EP 32040 DI 10.1029/98JD00773 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000038 ER PT J AU Martins, JV Artaxo, P Liousse, C Reid, JS Hobbs, PV Kaufman, YJ AF Martins, JV Artaxo, P Liousse, C Reid, JS Hobbs, PV Kaufman, YJ TI Effects of black carbon content, particle size, and mixing on light absorption by aerosols from biomass burning in Brazil SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTEGRATING SPHERE TECHNIQUES; OPTICAL-PROPERTIES; ATMOSPHERIC PARTICLES; ASYMMETRY PARAMETER; ELEMENTAL CARBON; SMOKE PARTICLES; COEFFICIENT; PLATE; SCATTERING; SOOT AB Black carbon mass absorption efficiencies of smoke particles were measured for various types of biomass fires during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) experiment using thermal evolution measurements for black carbon and optical absorption methods. The obtained results range between 5.2 and 19.3 m(2) g(-1) with an average value of 12.1 +/- 4.0 m(2) g(-1). Particle size distributions and optical properties were also measured to provide a full set of physical parameters for modeling calculations. Mie theory was used to model the optical properties of the particles assuming both internal and external mixtures coupling the modeling calculations with the experimental results obtained during the campaign. For internal mixing, a particle model with a layered structure consisting of an absorbing black carbon core, surrounded by a nonabsorbing shell, was assumed. Also, for internal mixing, a discrete dipole approximation code was used to simulate packed soot clusters commonly found in electron microscopy photographs of filters collected during the experiment, The modeled results for layered spheres and packed clusters explain black carbon mass absorption coefficients up to values of about 25 m(2) g(-1), but measurements show even higher values which were correlated with the chemical composition and characteristics of the structure of the particles. Unrealistic high values of black carbon absorption efficiencies were linked to high concentrations of K, which influence the volatilization of black carbon (BC) at lower temperatures than usual, possibly causing artifacts in the determination of BC by thermal technique. The modeling results are compared with nephelometer and light absorption measurements. C1 Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CEA, CNRS, Ctr Faibles Radioact, F-91198 Gif Sur Yvette, France. RP Univ Sao Paulo, Inst Fis, CP 66318, BR-05315970 Sao Paulo, Brazil. EM vanderlei@if.usp.br RI Reid, Jeffrey/B-7633-2014; Artaxo, Paulo/E-8874-2010 OI Reid, Jeffrey/0000-0002-5147-7955; Artaxo, Paulo/0000-0001-7754-3036 NR 31 TC 165 Z9 173 U1 5 U2 29 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 DEC 27 PY 1998 VL 103 IS D24 BP 32041 EP 32050 DI 10.1029/98JD02593 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000039 ER PT J AU Kaufman, YJ AF Kaufman, YJ TI Preface SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material ID CLIMATE C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. NR 12 TC 3 Z9 3 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 DEC 27 PY 1998 VL 103 IS D24 BP 32139 EP 32140 DI 10.1029/98JD02796 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000048 ER PT J AU Gao, BC Kaufman, YJ Han, W Wiscombe, WJ AF Gao, BC Kaufman, YJ Han, W Wiscombe, WJ TI Correction of thin cirrus path radiances in the 0.4-1.0 mu m spectral region using the sensitive 1.375 mu m cirrus detecting channel SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATIVE-TRANSFER; CLOUD; MODIS; SCATTERING; AEROSOL AB We have developed an empirical algorithm for removing thin cirrus effects from AVIRIS (airborne visible infrared imaging spectrometer) images at any wavelength in the region 0.4-1 mu m using narrow channels near 1.38, 1.24, and 0.66 mu m. In this algorithm the imaging pair of 1.38 and 1.24 mu m channels is used for cirrus removal over water surfaces, while the imaging pair of 1.38 and 0.66 mu m channels is used over land surfaces. The AVIRIS data on which the algorithm is based were measured from an ER-2 aircraft at 20 km altitude during several field programs over both land and ocean, From these data we earlier discovered that narrow channels near the center of the strong 1.38-mu m water vapor bands are very sensitive in detecting thin cirrus clouds. The present paper is a logical continuation of that work. Our new algorithm has considerable generality. As a first application, it can be incorporated as a front end to the first-generation moderate resolution imaging spectrometer (MODIS) (on EOS AM and PM platforms) atmospheric correction algorithms for ocean color and land applications in order to yield improved atmospheric aerosol, land surface, and ocean color products. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. SFA Inc, Largo, MD 20774 USA. RP USN, Res Lab, Remote Sensing Div, Code 7212, Washington, DC 20375 USA. EM gao@neptune.nrl.navy.mil RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 15 TC 41 Z9 44 U1 1 U2 6 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 DEC 27 PY 1998 VL 103 IS D24 BP 32169 EP 32176 DI 10.1029/98JD02006 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000051 ER PT J AU Kahn, R Banerjee, P McDonald, D Diner, DJ AF Kahn, R Banerjee, P McDonald, D Diner, DJ TI Sensitivity of multiangle imaging to aerosol optical depth and to pure-particle size distribution and composition over ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTHROPOGENIC AEROSOLS; SATELLITE; SHAPE AB Multiangle, multispectral remote sensing observations, such as those anticipated from the Earth Observing System (EOS) Multiangle Imaging Spectroradiometer (MISR), can significantly improve our ability to constrain aerosol properties from space. Simulations over cloud-free, calm ocean conditions were studied for pure particles with natural ranges of optical depth, particle size, and indices of refraction. According to the theoretical simulations we can retrieve column optical depth from measurements over calm ocean for all but the darkest particles, with typical size distributions and compositions, to an uncertainty of at most 0.05 or 20%, whichever is larger, even if the particle properties are poorly known. For one common particle type, soot, constraints on the optical depth over dark ocean are very poor. The simulated measurements also allow us to distinguish spherical from nonspherical particles, to separate two to four compositional groups based on indices of refraction, and to identify three to four distinct size groups between 0.1 and 2.0 mu m characteristic radius at most latitudes. The technique is most sensitive to particle microphysical properties in the "accumulation mode" sizes, where particle scattering undergoes the transition from Rayleigh to large-particle regimes for the MISR wavelengths. On the basis of these results we expect to distinguish air masses containing different aerosol types, routinely and globally, with multiangle remote sensing data. Such data complement in situ and field data, which can provide detailed information about aerosol size and composition locally. An extension of this study to mixtures of pure particles is part of continuing work. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-237, Pasadena, CA 91109 USA. EM ralph.kahn@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 25 TC 97 Z9 99 U1 1 U2 7 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 DEC 27 PY 1998 VL 103 IS D24 BP 32195 EP 32213 DI 10.1029/98JD01752 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000053 ER PT J AU Kaufman, YJ Justice, CO Flynn, LP Kendall, JD Prins, EM Giglio, L Ward, DE Menzel, WP Setzer, AW AF Kaufman, YJ Justice, CO Flynn, LP Kendall, JD Prins, EM Giglio, L Ward, DE Menzel, WP Setzer, AW TI Potential global fire monitoring from EOS-MODIS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE DETECTION; SAVANNA ECOSYSTEMS; WATER-VAPOR; DATA SET; BIOMASS; AEROSOL; SMOKE; RESOLUTION; IDENTIFICATION; EMISSIONS AB The National Aeronautic and Space Administration (NASA) plans to launch the moderate resolution imaging spectroradiometer (MODIS) on the polarorbiting Earth Observation System (EOS) providing morning and evening global observations in 1999 and afternoon and night observations in 2000. These four MODIS daily fire observations will advance global fire monitoring with special 1 km resolution fire channels at 4 and 11 rim with high saturation of about 450 and 400 K, respectively. MODIS data will also be used to monitor burn scars, vegetation type and condition, smoke aerosols, water vapor, and clouds for overall monitoring of the fire process and its effets on ecosystems, the atmosphere, and the climate. The MODIS fire science team is preparing algorithms that use the thermal signature to separate the fire signal from the background signal. A database of active fire products will be generated and archived at a 1 km resolution and summarized on a grid of 10 km and 0.5 degrees, daily, 8 days, and monthly. It includes the fire occurrence and location, the rate of emission of thermal energy from the fire, and a rough estimate of the smoldering/flaming ratio.. This information will be used in monitoring the spatial and temporal distribution of fires in different ecosystems, detecting changes in fire distribution and identifying new fire frontiers, wildfires, and changes in the frequency of the fires or their relative strength. We plan to combine the MODIS fire measurements with a detailed diurnal cycle of the fires from geostationary satellites. Sensitivity studies and analyses of aircraft and satellite data from the Yellowstone wildfire of 1988 and prescribed fires in the Smoke, Clouds, and Radiation (SCAR) aircraft field experiments are used to evaluate and validate the fire algorithms and to establish the relationship between the fire thermal properties, the rate of biomass consumption, and the emissions of aerosol and trace gases from fires. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. Univ Hawaii, Hawaii Inst Geophys & Planets, Honolulu, HI 96822 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. US Forest Serv, Intermt Res Stn, USDA, Missoula, MT USA. NOAA, NESDIS, Madison, WI 53706 USA. Inst Pesquisas Espaciais, Sao Paulo, Brazil. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM justice@kratmos.gsfc.nasa.gov RI Menzel, W. Paul/B-8306-2011 OI Menzel, W. Paul/0000-0001-5690-1201 NR 83 TC 270 Z9 292 U1 4 U2 37 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 DEC 27 PY 1998 VL 103 IS D24 BP 32215 EP 32238 DI 10.1029/98JD01644 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000054 ER PT J AU Knyazikhin, Y Martonchik, JV Diner, DJ Myneni, RB Verstraete, M Pinty, B Gobron, N AF Knyazikhin, Y Martonchik, JV Diner, DJ Myneni, RB Verstraete, M Pinty, B Gobron, N TI Estimation of vegetation canopy leaf area index and fraction of absorbed photosynthetically active radiation from atmosphere-corrected MISR data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID REFLECTANCE; SOIL AB The multiangle imaging spectroradiometer (MISR) instrument is designed to provide global imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. This paper describes an algorithm for the retrieval of leaf area index (LAI) and fraction of photosynthetically active radiation absorbed by vegetation (FPAR) from atmospherically corrected MISR data. The proposed algorithm is designed to utilize all the information provided by this instrument, using a two-step process. The first step involves a comparison of the retrieved spectral hemispherically integrated reflectances with those determined from the model which depend on biome type, canopy structure, and soil/understory reflectances. The biome/canopy/soil/understory models that pass this comparison test are subject to the second step, which is a comparison of their directional reflectances at the MISR angles to the retrieved spectral directional reflectances. This procedure, however, can produce multiple acceptable solutions. The measure theory is used to specify the most probable values of LAI and FPAR using the set of all acceptable solutions. Optimization of the retrieval technique for efficient global processing is discussed. This paper is the second of a two-part set describing a synergistic algorithm for producing global LAI and FPAR fields from canopy reflectance data provided by the MODIS (moderate resolution imaging spectroradiometer) and MISR instruments. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Commiss European Communities, Joint Res Ctr, Space Applicat Inst, I-21020 Ispra, VA, Italy. RP Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM jknjazi@crsa.bu.edu; jvm@jord.jpl.nasa.gov; djd@jord.jpl.nasa.gov; rmyneni@crsa.bu.edu; michel.verstraete@jrc.it; bernard.pinty@irc.it; nadine.gobron@jrc.it RI Myneni, Ranga/F-5129-2012; OI Verstraete, Michel/0000-0003-0968-8721 NR 27 TC 200 Z9 217 U1 5 U2 25 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 DEC 27 PY 1998 VL 103 IS D24 BP 32239 EP 32256 DI 10.1029/98JD02461 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000055 ER PT J AU Knyazikhin, Y Martonchik, JV Myneni, RB Diner, DJ Running, SW AF Knyazikhin, Y Martonchik, JV Myneni, RB Diner, DJ Running, SW TI Synergistic algorithm for estimating vegetation canopy leaf area index and fraction of absorbed photosynthetically active radiation from MODIS and MISR data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID REFLECTANCE; TRANSPORT; MODELS AB A synergistic algorithm for producing global leaf area index and fraction of absorbed photosynthetically active radiation fields from canopy reflectance data measured by MODIS (moderate resolution imaging spectroradiometer) and MISR (multiangle imaging spectroradiometer) instruments aboard the EOS-AM I platform is described here. The proposed algorithm is based on a three-dimensional formulation of the radiative transfer process in vegetation canopies. It allows the use of information provided by MODIS (single angle and up to 7 shortwave spectral bands) and MISR (nine angles and four shortwave spectral bands) instruments within one algorithm. By accounting features specific to the problem of radiative transfer in plant canopies, powerful techniques developed in reactor theory and atmospheric physics are adapted to split a complicated three-dimensional radiative transfer problem into two independent, simpler subproblems, the solutions of which are stored in the form of a look-up table. The theoretical background required for the design of the synergistic algorithm is discussed. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Montana, Sch Forestry, Missoula, MT 59812 USA. RP Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM jknjazi@crsa.bu.edu; jvm@jord.jpl.nasa.gov; rmyneni@crsa.bu.edu; djd@jord.jpl.nasa.gov; swr@ntsg.umt.edu RI Myneni, Ranga/F-5129-2012 NR 50 TC 424 Z9 461 U1 6 U2 41 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 DEC 27 PY 1998 VL 103 IS D24 BP 32257 EP 32275 DI 10.1029/98JD02462 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000056 ER PT J AU Wald, AE Kaufman, YJ Tanre, D Gao, BC AF Wald, AE Kaufman, YJ Tanre, D Gao, BC TI Daytime and nighttime detection of mineral dust over desert using infrared spectral contrast SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SAHARAN-DUST; OPTICAL-THICKNESS; AEROSOLS; RETRIEVAL; AFRICA; IMPACT; OCEAN AB Desert dust has a potentially strong effect on climate and climate forcing as evident from satellite data, yet its detection close to its sources over deserts and semidesert regions is difficult. The lifted dust often has the same mineral composition as the surface sand left behind. The main consistent difference between airborne dust and surface sand is particle size. This difference is used here to develop a remote sensing technique for the detection of dust over desert. The technique uses two infrared channels that will be on the Earth Observing System (EOS) moderate resolution imaging spectroradiometer (MODIS). It is based on measurements and modeling of the thermal infrared spectrum of silicate and carbonate minerals that show strong differences between the thermal properties of the smaller dust particles (diameter of 2-5 mu m) and the larger sand particles (diameter > 70 mu m). In particular, the emissivity of quartz increases with the particle size at 11 mu m and decreases at 8.6 mu m. This different behavior allows use of these two MODIS channels to distinguish between variations of the dust temperature and surface temperature from the variation in the loading of the smaller dust particles in the atmosphere. We report simulations of the technique for day and night remote sensing and apply it to high resolution infrared sounder (HIRS) data which is validated against ground-based measurements by Sun photometers. The technique is found to be sensitive to the dust loading over sand surfaces and not very sensitive to the dust height. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Sci & Tech Lille Flandres Artois, Lab Opt Atmospher, F-59655 Villeneuve Dascq, France. USN, Res Lab, Washington, DC 20375 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Sci, Baltimore, MD 21228 USA. RP NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 913, Greenbelt, MD 20771 USA. EM wald@climate.gsfc.nasa.gov; kaufman@climate.gsfc.nasa.gov; Didier.Tanre@univ-lille1.fr; gao@neptune.nrl.navy.mil NR 36 TC 41 Z9 45 U1 0 U2 6 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 DEC 27 PY 1998 VL 103 IS D24 BP 32307 EP 32313 DI 10.1029/98JD01454 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155VL UT WOS:000077967000059 ER PT J AU Na, Y Moin, P AF Na, Y Moin, P TI The structure of wall-pressure fluctuations in turbulent boundary layers with adverse pressure gradient and separation SO JOURNAL OF FLUID MECHANICS LA English DT Article ID CHANNEL FLOW; SIMULATION AB Space-time correlations and frequency spectra of wall-pressure fluctuations, obtained from direct numerical simulation, are examined to reveal the effects of pressure gradient and separation on the characteristics of wall-pressure fluctuations. In the attached boundary layer subjected to adverse pressure gradient, contours of constant two-point spatial correlation of wall-pressure fluctuations are more elongated in the spanwise direction. Convection velocities of wall-pressure fluctuations as a function of spatial and temporal separations are reduced by the adverse pressure gradient. In the separated turbulent boundary layer, wall-pressure fluctuations are reduced inside the separation bubble, and enhanced downstream of the reattachment region where maximum Reynolds stresses occur. Inside the separation bubble, the frequency spectra of wall-pressure fluctuations normalized by the local maximum Reynolds shear stress correlate well compared to those normalized by free-stream dynamic pressure, indicating that local Reynolds shear stress has more direct influence on the wall-pressure spectra. Contour plots of two-point correlation of wall-pressure fluctuations are highly elongated in the spanwise direction inside the separation bubble, implying the presence of large two-dimensional roller-type structures. The convection velocity determined from the space-time correlation of wall-pressure fluctuations is as low as 0.33U(0) (U(0) is the maximum inlet velocity) in the separated zone, and increases downstream of reattachment. C1 Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Na, Y (reprint author), Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. NR 29 TC 48 Z9 50 U1 0 U2 15 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD DEC 25 PY 1998 VL 377 BP 347 EP 373 DI 10.1017/S0022112098003218 PG 27 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 161ZU UT WOS:000078321100014 ER PT J AU Chanover, NJ Glenar, DA Hillman, JJ AF Chanover, NJ Glenar, DA Hillman, JJ TI Multispectral near-IR imaging of Venus nightside cloud features SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID DARK SIDE; GALILEO; IMAGES; CIRCULATION; LEVEL; WINDS AB Near-infrared imaging observations of the Venus nightside were made on May 17-23, 1996, at the Apache Point Observatory. The data were taken with an acousto-optic tunable filter camera (AOTF), which is a newly developed, RF;tunable imager with a spectral resolution of lambda/Delta lambda = 422 at 2.3 mu m. The observations;were made at several discrete wavelengths in the 2.3 mu m spectral window in the Venus atmosphere that correspond to molecular absorption minima and maxima of several species. These data are sensitive to properties of the lower cloud deck of Venus; we examined the zonal wind speeds near an altitude of 50 km and studied the implications of the brightness contrasts seen in the images. We confirmed the similar to 5-day rotational period of the cloud features previously seen at this altitude level. We also confirmed previously reported contrast ratios between the brightest and darkest regions of 20:1 and found that this contrast ratio corresponds to a variation in optical depth of at least 8. We demonstrated the new technology of the near-IR AOTF camera by illustrating one of its many applications for planetary science. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Chanover, NJ (reprint author), New Mexico State Univ, Dept Astron, Box 30001-MSC 4500, Las Cruces, NM 88003 USA. NR 27 TC 20 Z9 20 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 DEC 25 PY 1998 VL 103 IS E13 BP 31335 EP 31348 DI 10.1029/1998JE900009 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600002 ER PT J AU Delitsky, ML Lane, AL AF Delitsky, ML Lane, AL TI Ice chemistry on the Galilean satellites SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PROTON IRRADIATED H2O+CO2; GANYMEDE MAGNETIC-FIELD; ION IRRADIATION; CARBONIC-ACID; WATER ICE; ASTROPHYSICAL ICES; JUPITER; MAGNETOSPHERE; SURFACE; CO AB Jupiter's icy satellites Europa, Ganymede, and Callisto are subject to energy fluxes from; electrons, photons, and magnetospheric plasma ion bombardment. As water ice and CO2, ice are thought to be present on their surfaces, the radiolysis of these materials over time should produce more complicated CHO-containing molecules. These may include CH3OH, H2CO, CH2CO, C3O2, HCOOH, CH3COOH, H2CO3, HCOOCH, (CH3)(2)CO, CH3CH2OH, HOCH2CK2OH, polymeric C3O2, and polymeric H2CO. The water fragmentation products OH, O-2, HO2, H2O2, and O-3 should also be produced. The molecules formed should be detectable with ground-based intruments because of their many active infrared bands. Another product produced is CO, which will have a high vapor pressure over a Galilean satellite surface at typical temperatures. The vapor pressure of CO at the nighttime temperature of 70 K could be as high as 150 mbar. Ganymede's unique dipolar magnetic field should induce more chemistry in its polar regions due to the focusing of radiation to higher latitudes. The observed lack of leading/trailing asymmetry in its SO2 absorption correlates with this redirection of plasma ions toward the poles. The observance of O atom emissions at high latitudes by Hall et al. [1998] is also consistent with this picture. The ratio of plasma energies directed to the poles to those directed to the equatorial regions is similar to 4. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Delitsky, ML (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-237, Pasadena, CA 91109 USA. EM mona.delitsky@jpl.nasa.gov; arthur.l.lane@jpl.nasa.gov NR 73 TC 47 Z9 48 U1 1 U2 8 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 DEC 25 PY 1998 VL 103 IS E13 BP 31391 EP 31403 DI 10.1029/1998JE900020 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600005 ER PT J AU Clifford, S Treiman, A Newsom, H Farmer, J AF Clifford, S Treiman, A Newsom, H Farmer, J TI Introduction to special section: Early Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Editorial Material C1 Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Mexico, Dept Earth & Planetary Sci, Inst Meteorit, Albuquerque, NM 87131 USA. RP Clifford, S (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 5 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 DEC 25 PY 1998 VL 103 IS E13 BP 31405 EP 31405 DI 10.1029/98JE01896 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600006 PM 11542258 ER PT J AU Nyquist, LE Borg, LE Shih, CY AF Nyquist, LE Borg, LE Shih, CY TI The Shergottite age paradox and the relative probabilities for Martian meteorites of differing ages SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SNC METEORITES; THERMAL HISTORY; IMPACT EJECTA; ORIGIN; MARS; ACHONDRITES; SYSTEMATICS; CHRONOLOGY; EVOLUTION; ALH84001 AB The apparent paradox that the majority of impacts yielding Martian meteorites appear to have taken place on only a few percent of the Martian surface can be resolved if all the shergottites were ejected in a single event rather than in multiple events. The apparent degree by which shergottites are overrepresented among Martian meteorites is thereby reduced to about fourfold relative to other types of Martian meteorites for nominal cratering rate models, and further reduced for higher cratering rate models. If the shergottite-ejection event is assigned to one of three craters in the vicinity of Olympus Mons that were previously identified as candidate source craters for the SNC (shergottites, nakhlites, Chassigny) meteorites, and the nakhlite/chassignite event is assigned to a candidate crater in the vicinity of Ceraunius Tholus, the implied ages of the surrounding terrains agree well with crater density ages. Because of their young crystallization ages, the likely origin of the shergottites is in the Tharsis region even for cratering rates up to twice the nominal value (minimum terrain ages). For these higher cratering rates, the nakhlite source need not be in the Tharsis region. Since the source of the ancient orthopyroxenite, ALH84001, was probably in the ancient southern uplands, meteorite-yielding impacts may have been widely dispersed on the Martian surface. C1 NASA, Lyndon B Johnson Space Ctr, Natl Res Council, Houston, TX 77058 USA. Lockheed Engn & Sci Co, Houston, TX 77058 USA. RP Nyquist, LE (reprint author), NASA, Lyndon B Johnson Space Ctr, Natl Res Council, SN2, Houston, TX 77058 USA. EM laurence.e.nyquist1@jsc.nasa.gov; lborg@jsc.nasa.gov; chi-yu.shih1@jsc.nasa.gov NR 62 TC 30 Z9 30 U1 0 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 DEC 25 PY 1998 VL 103 IS E13 BP 31445 EP 31455 DI 10.1029/98JE01965 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600010 ER PT J AU Bishop, JL Froschl, H Mancinelli, RL AF Bishop, JL Froschl, H Mancinelli, RL TI Alteration processes in volcanic soils and identification of exobiologically important weathering products on Mars using remote sensing SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HAWAIIAN PALAGONITIC SOIL; 5-25 MU-M; REFLECTANCE SPECTROSCOPY; MAGNETIC-PROPERTIES; ANALOG MATERIALS; LOW-TEMPERATURE; IMAGING SPECTROSCOPY; SPECTRAL REFLECTANCE; REFLECTIVITY SPECTRA; AQUEOUS ALTERATION AB Determining the mineralogy of the Martian surface material provides information about the past and present environments on Mars which are an integral aspect of whether or not Mars was suitable for the origin of life. Mineral identification on Mars will most likely be achieved through visible-infrared remote sensing in combination with other analyses on landed missions. Therefore, understanding the visible and infrared spectral properties of terrestrial samples formed via processes similar to those thought to have occurred on Mars is essential to this effort and will facilitate site selection for future exobiology missions to Mars. Visible to infrared reflectance spectra are presented here for the fine-grained fractions of altered tephra/lava from the Haleakala summit basin on Maul, the Tarawera volcanic complex on the northern island of New Zealand, and the Greek Santorini island group. These samples exhibit a range of chemical and mineralogical compositions, where the primary minerals typically include plagioclase, pyroxene, hematite, and magnetite. The kind and abundance of weathering products varied substantially for these three sites due, in part, to the climate and weathering environment. The moist environments at Santorini and Tarawera are more consistent with postulated past environments on Mars, while the dry climate at the top of Haleakala is more consistent with the current Martian environment. Weathering of these tephra is evaluated by assessing changes in the leachable and immobile elements, and through detection of phyllosilicates and iron oxide/oxyhydroxide minerals. Identifying regions on Mars where phyllosilicates and many kinds of iron oxides/oxyhydroxides are present would imply the presence of water during alteration of the surface material. Tephra samples altered in the vicinity of cinder cones and steam vents contain higher abundances of phyllosilicates, iron oxides, and sulfates and may be interesting sites for exobiology. C1 NASA, Ames Res Ctr, NRC, Moffett Field, CA 94035 USA. Austrian Res & Testing Ctr Arsenal, Analyt Geochem Dept, A-1030 Vienna, Austria. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Bishop, JL (reprint author), NASA, Ames Res Ctr, NRC, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM jbishop@mail.arc.nasa.gov; Froeschl.H@arsenal.ac.at; rmancinelli@mail.arc.nasa.gov RI Mancinelli, Rocco/L-8971-2016 NR 96 TC 29 Z9 29 U1 1 U2 7 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 DEC 25 PY 1998 VL 103 IS E13 BP 31457 EP 31476 DI 10.1029/1998JE900008 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600011 PM 11542259 ER PT J AU Vaniman, D Bish, D Blake, D Elliott, ST Sarrazin, P Collins, SA Chipera, S AF Vaniman, D Bish, D Blake, D Elliott, ST Sarrazin, P Collins, SA Chipera, S TI Landed XRD/XRF analysis of prime targets in the search for past or present Martian life SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS; PRESERVATION; FOSSILS; DEVICES AB Mars landers seeking evidence for past or present life will be guided by information from orbital mapping and from previous surface exploration. Several target options have been proposed, including sites that may harbor extant life and sites most likely to preserve evidence of past life. These sites have specific mineralogic characteristics. Extant life might be gathered around the sinters and associated mineral deposits of rare active fumaroles, or held within brine pockets and inclusions in a few evaporite-mineral deposits. Possibilities for fossilization include deltaic and lake-bottom sediments of once-flooded craters, sinters formed by ancient hot-spring deposits, and the carbonate deposits associated with some evaporite systems. However, the highly varied mineralogy of fossil occurrences on Earth leads to the inference that Mars, an equally complex planet, could host a broad variety of potential fossilizing deposits. The abundance of volcanic systems on Mars and evidence for close associations between volcanism and water release suggest possibilities of organism entrapment and mineralization in volcaniclastic deposits, as found in some instances on Earth. Thus the targets being considered for exploration include a wide variety of unique deposits that would be characterized by silica or various nonsilicate minerals. Beyond these "special" deposits and in the most general case, an ability to distinguish mineralized from uncemented volcanic detritus may be the key to success in finding possible fossil-bearing authigenic mineralogies. A prototype miniaturized X ray diffraction/X ray fluorescence (XRD/XRF) instrument has been evaluated with silica, carbonate, and sulfate minerals and with a basalt, to examine the capabilities of this tool in mineralogic and petrologic exploration for exo-biological goals. This instrument, CHEMIN (chemical and mineralogical analyzer), is based on an innovative low-power X ray tube, transmission geometry, and CCD collection and discrimination of diffracted and fluoresced X rays. The ability to accumulate and integrate the entire circumference of each complete Debye diffraction ring compensates for poor powder preparations, as might be produced by robotic sampling systems. With CHEMIN, a wide range of minerals can be uniquely identified. Using Rietveld analysis of the XRD results, mineral quantification is also possible. Expanded capabilities in phase analysis and constrained data solutions using quantitative XRD and XRF are within reach. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Etablissement Natl Enseignement Super Agron Dijon, Lab Genie Agroequipements Procedes, F-21800 Quetigny, France. RP Vaniman, D (reprint author), Univ Calif Los Alamos Natl Lab, MS D462, Los Alamos, NM 87545 USA. NR 41 TC 15 Z9 15 U1 3 U2 14 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 DEC 25 PY 1998 VL 103 IS E13 BP 31477 EP 31489 DI 10.1029/98JE01428 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600012 PM 11542260 ER PT J AU Zent, AP AF Zent, AP TI On the thickness of the oxidized layer of the Martian regolith SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS; LIFE; SOIL; ATMOSPHERE; SURFACE; H2O AB A revised model of the diffusion of H2O2 through the Martian regolith is presented, which argues that oxidant diffusion may be more efficient than previously thought. Recent models of the adsorption of H2O at Mars-like conditions indicate that it adsorbs more poorly than previously believed. H2O adsorption is a necessary proxy for peroxide adsorption; hence the adsorptive slowing of peroxide diffusion is modeled as less efficient. Because the peroxide has a finite lifetime, it has a finite extinction depth as well. The effects of regolith gardening by impacts are quantitatively estimated and combined with the effects of oxidation by atmospheric gases to produce estimates of the degree of oxidation of the Martian surface with depth. We explore the effects of different crater production populations along with variations in H2O2 extinction depths, and hydrothermal oxidation of ejects. In very select circumstances involving very early onset of oxidizing conditions during heavy bombardment, 150-200 m of regolith could be fully oxidized. More likely scenarios for the crater production population, onset of oxidizing conditions, and oxidant extinction depth yield estimates of no more than a few meters to putative reducing material. In addition, uncertainties remain regarding the degree to which hydrothermal or other high-temperature chemistry might oxidize materials in ejecta blankets. The trade-off between accessing unlithified sediments or rock interiors must be considered. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Zent, AP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 36 TC 43 Z9 43 U1 0 U2 6 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 DEC 25 PY 1998 VL 103 IS E13 BP 31491 EP 31498 DI 10.1029/98JE01895 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 154QU UT WOS:000077900600013 PM 11542261 ER PT J AU Asai, K Dotani, T Hoshi, R Tanaka, Y Robinson, CR Terada, K AF Asai, K Dotani, T Hoshi, R Tanaka, Y Robinson, CR Terada, K TI ASCA observations of transient x-ray sources in quiescence SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE black holes; stars : neutron; X-rays : binaries; X-rays : sources ID ADVECTION-DOMINATED ACCRETION; GAS IMAGING SPECTROMETER; BLACK-HOLE; CENTAURUS X-4; DYNAMICAL EVIDENCE; ROSAT OBSERVATIONS; NEUTRON-STAR; V404 CYGNI; MODEL; MASS AB Soft X-ray transients are most probably low-mass binary systems containing either a neutron star (NS-LMXB) or a black hole (BH-LMXB). We have systematically investigated thirteen soft X-ray transients (four NS-LMXBs and nine BH-LMXBs) in the quiescent state using the available ASCA data. The luminosities of the observed NS-LMXBs in quiescence are on the order of similar to 10(32-33) erg s(-1), whereas those of the BH-LMXBs are found to be systematically lower, most of them giving upper limits in the range below 10(32) erg s(-1). The quiescent luminosity of LMXBs may be explained in terms of an optically thin, advection-dominated accretion disk, for which most of the thermal and kinetic energies of accreting matter are advected into the compact object with little X-ray emission. However, this scenario predicts a much larger luminosity for NS-LMXBs than observed, if the advected energies are liberated at the neutron-star surface, which is absent in BH-LMXBs. Mass accretion onto the neutron-star surface may be suppressed through some mechanism, such as the so-called propeller effect. The soft component observed in the NS-LMXBs is most probably emission from the magnetic pole regions of the neutron star. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Rikkyo Univ, Dept Phys, Tokyo 1718501, Japan. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Hiroshima Univ, Fac Sci, Dept Earth & Planetary Syst Sci, Higashihiroshima, Hiroshima 7398526, Japan. RP Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan. EM asai@astro.isas.ac.jp NR 49 TC 90 Z9 90 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD DEC 25 PY 1998 VL 50 IS 6 BP 611 EP 619 DI 10.1093/pasj/50.6.611 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152YD UT WOS:000077804700010 ER PT J AU Francisco, JS Parthiban, S Lee, TJ AF Francisco, JS Parthiban, S Lee, TJ TI Adiabatic electron affinity and ionization potential for BrO radical SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; TRIPLE EXCITATIONS; MOLECULAR CALCULATIONS; LOWER STRATOSPHERE; ENERGIES; SPECTROSCOPY; ATOMS; CLO; IO; CONTRACTION AB The adiabatic electron affinity (EA) and ionization potential (IP) for the BrO radical have been computed at high levels of theory. Specifically, the singles and doubles coupled-cluster method that includes a perturbational correction for connected triple excitations, denoted CCSD(T), has been used in conjunction with several one-particle basis sets. The largest basis sets are of the atomic natural orbital (ANO) type and include up through g functions. Our best IP and EA values, 241.1 +/- 0.8 and 55.6 +/- 1.8 kcal mol(-1), respectively, have been obtained by extrapolating the CCSD(T)/ANO results to the one-particle basis-set limit, and are in excellent agreement with the latest experimental values. Our best computed IP shows, definitively, that the experimental result due to Monks ct al. is more reliable than the value given by Lias et al. The reliability of our CCSD(T)/ANO calculations is also demonstrated by the excellent agreement between experiment and our best calculations for the BrO and BrO- equilibrium bond distances and vibrational frequencies. Our calculations provide the most reliable equilibrium bond distance, 1.640 Angstrom, and vibrational frequency, 854 cm(-1), for BrO+ to date, since experimental data are unavailable. Based on the agreement found for BrO and BrO-, we expect the BrO+ bond distance and vibrational frequency to be accurate to within +/-0.005 Angstrom and +/-20 cm(-1), respectively. (C) 1998 American Institute of Physics. [S0021-9606(98)30248-2]. C1 Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RI Lee, Timothy/K-2838-2012 NR 38 TC 13 Z9 13 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 22 PY 1998 VL 109 IS 24 BP 10818 EP 10822 DI 10.1063/1.477778 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 148QB UT WOS:000077542400029 ER PT J AU Asnin, VM Krainsky, IL AF Asnin, VM Krainsky, IL TI Fine structure in the secondary electron emission peak for diamond crystal with (100) negative electron affinity surface SO APPLIED PHYSICS LETTERS LA English DT Article ID EXCITON BREAKUP; PHOTOEMISSION; SPECTROSCOPY AB A fine structure was discovered in the low-energy peak of the secondary electron emission spectra of the diamond surface with negative electron affinity. We studied this structure for the (100) surface of the natural type-IIb diamond crystal. We have found that the low-energy peak consists of a total of four maxima, The relative energy positions of three of them could be related to the electron energy minima near the bottom of the conduction band. The fourth peak, having the lowest energy, was attributed to the breakup of the bulk exciton at the surface during the process of secondary electron emission. (C) 1998 American Insitute of Physics. [S0003-6951(98)02751-X]. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Asnin, VM (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 24 TC 13 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 21 PY 1998 VL 73 IS 25 BP 3727 EP 3729 DI 10.1063/1.122876 PG 3 WC Physics, Applied SC Physics GA 146XH UT WOS:000077458200034 ER PT J AU Rolfes, R Noor, AK Sparr, H AF Rolfes, R Noor, AK Sparr, H TI Evaluation of transverse thermal stresses in composite plates based on first-order shear deformation theory SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID LAMINATED PLATES; ELEMENTS; PREDICTION AB A postprocessing procedure is presented for the evaluation of the transverse thermal stresses in laminated plates. The analytical formulation is based on the first-order shear deformation theory and the plate is discretized by using a single-field displacement finite element model. The procedure is based on neglecting the derivatives of the in-plane forces and the twisting moments, as well as the mixed derivatives of the bending moments, with respect to the in-plane coordinates. The calculated transverse shear stiffnesses reflect the actual stacking sequence of the composite plate. The distributions of the transverse stresses through-the-thickness are evaluated by using only the transverse shear forces and the thermal effects resulting from the finite element analysis. The procedure is implemented into a postprocessing routine which can be easily incorporated into existing commercial finite element codes. Numerical results are presented for four- and ten-layer cross-ply laminates subjected to mechanical and thermal loads. Published by Elsevier Science S.A. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. German Aerosp Res Estab, DLR, Inst Struct Mech, Braunschweig, Germany. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. NR 20 TC 48 Z9 51 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD DEC 21 PY 1998 VL 167 IS 3-4 BP 355 EP 368 DI 10.1016/S0045-7825(98)00150-9 PG 14 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 156KW UT WOS:000078001100010 ER PT J AU Jenniskens, P Betlem, H de Lignie, M ter Kuile, C van Vliet, MCA van't Leven, J Koop, M Morales, E Rice, T AF Jenniskens, P Betlem, H de Lignie, M ter Kuile, C van Vliet, MCA van't Leven, J Koop, M Morales, E Rice, T TI On the unusual activity of the Perseid meteor shower (1989-96) and the dust trail of comet 109P/Swift-Tuttle SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE comets : individual : 109P/Swift-Tuttle; meteors, meteoroids; Solar system : general ID STREAM ACTIVITY; P/SWIFT-TUTTLE; PERIOD; MOTION; ORBITS; STORMS AB We present the first measurements of the radiant and orbit of meteoroids that are part of the unusual Perseid activity called the 'Perseid Filament'. This filament was encountered by Earth in the years before and after the return of the comet to perihelion in December of 1992. Between 1989 and 1996, there were brief meteor outbursts of near-constant duration with a symmetric activity profile. In 1993, however, rates increased more gradually to the peak. That gradual increase is identified here as a separate dust component, which we call the 'Nodal Blanket'. We find that the Nodal Blanket has a very small radiant dispersion. On the other hand, the Perseid Filament has a radiant that is significantly dispersed and systematically displaced by 0.3 degrees. This dispersion implies that unusually high ejection velocities or planetary perturbations must have had time to disperse the stream. In both cases, one would expect a rapid dispersion of matter along the comet orbit. In order to explain the concentration of dust near the comet position, we propose a novel scenario involving long-term accumulation in combination with protection of the region near the comet against close encounters with Jupiter due to librations of the comet orbit around the 1:11 mean-motion resonance. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Dutch Meteor Soc, NL-2318 NB Leiden, Netherlands. Calif Meteor Soc, San Jose, CA 92129 USA. SETI Inst, Mt View, CA USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM peter@max.arc.nasa.gov NR 62 TC 17 Z9 19 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD DEC 21 PY 1998 VL 301 IS 4 BP 941 EP 954 DI 10.1046/j.1365-8711.1998.02020.x PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 154DA UT WOS:000077872300005 ER PT J AU Fonte, P Peskov, V Ramsey, BD AF Fonte, P Peskov, V Ramsey, BD TI Rate and gain limitations of MSGCs and MGCs combined with GEM and other preamplification structures SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Wire Chamber Conference CY FEB 23-27, 1998 CL VIENNA, AUSTRIA ID GAS COUNTERS; FEEDBACK AB We have studied the rate and gain limits of diamond-coated Microstrip Gas Counters (MSGCs) and Micro-Gap Counters (MGCs) when combined with various preamplification structures: Gas Electron Multiplier (GEM), Parallel-Plate Avalanche Chamber (PPAC) or a MICROMEGAS-type structure. Measurements were done both with X-rays and alpha particles with various detector geometries and in different gas mixtures at pressures from 0.05 to 10 atm. The results obtained varied significantly with detector design, gas mixture and pressure, but some general features can be identified. We found that in all cases, bare MSGCs, MGCs, PPACs and MICROMEGAS, the maximum achievable gain drops with rate. The addition of preamplification structures significantly increases the gain of MSGCs and MGCs, but this gain is still rate dependent. There would seem to be a general rate-dependant effect governing the usable gain of all these detectors. We speculate on possible mechanisms for this effect, and identify a safe, spark-free, operation zone for each system (detector + preamplification structure) in the rate-gain coordinate plane. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, ES 84, Huntsville, AL 35812 USA. Univ Coimbra, LIP, Coimbra, Portugal. ESEC, Coimbra, Portugal. RP Peskov, V (reprint author), NASA, George C Marshall Space Flight Ctr, ES 84, Huntsville, AL 35812 USA. RI Fonte, Paulo/B-1842-2008 OI Fonte, Paulo/0000-0002-2275-9099 NR 13 TC 22 Z9 22 U1 0 U2 0 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 DEC 21 PY 1998 VL 419 IS 2-3 BP 405 EP 409 DI 10.1016/S0168-9002(98)00815-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 149WN UT WOS:000077629400033 ER PT J AU Treyer, M Scharf, C Lahav, O Jahoda, K Boldt, E Piran, T AF Treyer, M Scharf, C Lahav, O Jahoda, K Boldt, E Piran, T TI Large-scale fluctuations in the X-ray background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; diffuse radiation; large-scale structure of universe ID APM GALAXY SURVEY; POWER SPECTRUM; HEAO-1 AB We present an attempt to measure the large angular scale fluctuations in the X-ray background (XRB) from the HEAO 1 A2 data, expressed in terms of spherical harmonics. We model the harmonic coefficients assuming a power spectrum and an epoch-dependent bias parameter, b(X)(z), and using a phenomenological scenario describing the evolution of the X-ray sources. From the few low-order multipoles detected above shot noise, we estimate the power-spectrum normalization on scales intermediate between those explored by local galaxy redshift surveys (similar to 100 h(-1) Mpc) and those probed by the COBE cosmic microwave background (CMB) measurements (similar to 1000 h(-1) Mpc). We find that the HEAO 1 harmonics are consistent with present-epoch rms fluctuations of the X-ray sources b(X)(O)sigma(8) similar to 1-2 in 8 h(-1) Mpc spheres. Therefore, the observed fluctuations in the XRB are roughly as expected from interpolation between the local galaxy surveys and the COBE CMB experiment. We predict that an X-ray all-sky surface brightness survey resolving sources a factor of 10 fainter than HEAO 1 could reveal fluctuations to significantly larger scales, and therefore more strongly constrain the large-scale structure of the universe on scales of hundreds of Mpc. C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. RP Treyer, M (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. RI Jahoda, Keith/D-5616-2012 NR 33 TC 20 Z9 20 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP 531 EP 536 DI 10.1086/306515 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DH UT WOS:000079250700004 ER PT J AU Bautista, MA Kallman, TR Angelini, L Liedahl, DA Smits, DP AF Bautista, MA Kallman, TR Angelini, L Liedahl, DA Smits, DP TI Hydrogen-like ion emission in the spectra of low-mass X-ray binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; binaries : close; X-rays : stars ID RECOMBINATION-LINE-INTENSITIES; CASE-B CALCULATIONS; COEFFICIENTS AB We study the emission from H-like ions, particularly oxygen and neon, observed in ASCA spectra of low-mass X-ray binaries (LMXBs). The observed strengths of Ly alpha emission lines relative to the recombination continua differ from the classical recombination model. This suggests a different excitation mechanism for the lines. Various mechanisms are considered, which include three-body recombination, collisional excitation, recombination satellite line emission, and resonant fluorescent excitation. We find that the detection of Lyman recombination continuum implies that the plasma is photoionized, in agreement with previous studies by Hatchett, Buff, & McCray and Liedahl & Paerels. Under collisional ionization conditions, on the other hand, the Lyman continuum should be negligible unless the temperature were greater than 3 x 10(6) K. Otherwise, the enhancement of Ly alpha emission with respect to the continuum may be due to (1) three-body recombination at electron densities greater than 10(17) cm(-3) and temperatures below 2 x 10(5) K, (2) contributions to the recombination spectrum from collisional excitation of the H-like ionization stage, (3) contributions to recombination Ly alpha emission from satellite lines due to recombination onto the He-like ionization stage, and (4) contributions to the recombination spectrum from resonant fluorescence excitation of the H-like ionization stage. Further observations of higher order Lyman series lines and lines from other ionization stages are suggested to discriminate between the various excitation mechanisms. In addition, the implications of the different spectral formation mechanisms to the hydrodynamic accretion model of LMXBs are discussed. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. HartRAO, ZA-1740 Krugersdrop, South Africa. RP Bautista, MA (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 27 TC 15 Z9 15 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP 848 EP 855 DI 10.1086/306516 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DH UT WOS:000079250700032 ER PT J AU de Koter, A Heap, SR Hubeny, I AF de Koter, A Heap, SR Hubeny, I TI An empirical isochrone of very massive stars in R136a SO ASTROPHYSICAL JOURNAL LA English DT Article DE Magellanic Clouds; stars : early-type; stars : evolution; stars : fundamental parameters; stars : mass loss; ultraviolet : stars ID RADIATION-DRIVEN WINDS; HOT LUMINOUS STARS; O-TYPE STARS; HUBBLE-SPACE-TELESCOPE; LARGE MAGELLANIC CLOUD; NON-LTE ANALYSIS; X-RAY-EMISSION; STELLAR WINDS; LOSS RATES; TERMINAL VELOCITIES AB We report on a detailed spectroscopic study of 12 very massive and luminous stars (M greater than or similar to 35M.) in the core of the compact cluster R136a, near the center of the 30 Doradus complex. The three brightest stars of the cluster, R136a1, R136a2, and R136a3, have been investigated earlier by de Koter, Heap, & Hubeny. Low-resolution spectra (<200 km s(-1)) of the program stars were obtained with the GHRS and FOS spectrographs on the Hubble Space Telescope. These instruments covered the spectral range from 1200 to 1750 Angstrom and from 3200 to 6700 Angstrom, respectively. Fundamental stellar parameters were obtained by fitting the observations by model spectra calculated with the unified ISA-WIND code of de Koter et al. supplemented by synthetic data calculated using the program TLUSTY. We find that the stars are almost exclusively of spectral type O3. They occupy only a relatively narrow range in effective temperatures between 40 and 46 kK. The reason for these similar T-eff's is that the isochrone of these very massive stars, which we determined to be at similar to 2 Myr, runs almost vertically in the H-R diagram. We present a quantitative method of determining the effective temperature of O3-type stars based on the strength of the O v lambda 1371 line. Present-day evolutionary calculations by Meynet et al. imply that the program stars have initial masses in the range of M-i similar to 37-76 M.. The observed mass-loss rates are up to 3 (2) times higher than is assumed in these evolution tracks when adopting a metallicity Z = 0.004 (0.008) for the LMC. The high observed mass-loss rates imply that already at an age of similar to 2 Myr the most luminous of our program stars will have lost a significant fraction of their respective initial masses. For the least luminous stars investigated in this paper, the observed mass loss agrees with the prediction by the theory of radiation-driven winds (Kudritzki et al.). However, for increasing luminosity the observed mass loss becomes larger, reaching up to 3-4 times what is expected from the theory. Such an increasing discrepancy fits in with the results of de Koter et al., where an observed overpredicted mass-loss ratio of up to 8 was reported for the brightest members of the R136a cluster, for which M-i similar to 100 M. was found. The failure of the theory is also present when one compares observed over predicted wind momentum as a function of wind performance number. This strongly indicates that the shortcoming of the present state of the theory is connected to the neglect of effects of multiple photon momentum transfer. C1 Adv Comp Concepts, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Goddard Space Flight Ctr, Natl Opt Astron Observ, AURA, Greenbelt, MD 20771 USA. RP de Koter, A (reprint author), Adv Comp Concepts, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. EM dekoter@astro.uva.nl; hrsheap@hrs.dnet.nasa.gov; hubeny@stars.gsfc.nasa.gov NR 72 TC 57 Z9 57 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP 879 EP 896 DI 10.1086/306503 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DH UT WOS:000079250700035 ER PT J AU Bauschlicher, CW AF Bauschlicher, CW TI The reaction of polycyclic aromatic hydrocarbon cations with hydrogen atoms: The astrophysical implications SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : molecules; molecular data; molecular processes ID COUPLED-CLUSTER THEORY; GAUSSIAN-BASIS SETS; EMISSION FEATURES; ENERGIES AB The reaction of the naphthalene cation, C10H8+, with H atoms is exothermic by about 60 kcal mol(-1) and yields the 1-hydronaphthalene cation C10H9+. The addition of a second H atom is exothermic by about 45 kcal mol(-1), leading to the 1, 2-dihydronaphthalene cation C10H10+, which has less aromatic character than the parent naphthalene cation. Such products have been identified from the C-H stretching modes of the unidentified infrared bands. The abstraction of H from the 1-hydronaphthalene cation is found to have little, if any, barrier. This suggests that the polycyclic aromatic hydrocarbon (PAH) cations can catalyze the recombination of H atoms in the gas phase. Since the barrier to abstracting a deuterium is larger than hydrogen, reactions of hydrogen with PAH cations could enhance the degree of deuterium enrichment in PAHs. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, STC-230-3,Bldg 230,Room 205,Walcott Rd, Moffett Field, CA 94035 USA. NR 19 TC 69 Z9 69 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP L125 EP L127 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800016 ER PT J AU Charnley, SB AF Charnley, SB TI Stochastic astrochemical kinetics SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : molecules; methods : numerical; methods : statistical ID INTERSTELLAR CLOUDS; CHEMICAL-REACTIONS; DEPLETION; MOLECULES; CHEMISTRY; MODELS AB I present the first stochastic treatment of the chemical evolution of dense molecular clouds. The stochastic simulation algorithm, based on the Monte Carlo method, is described, and the computed solutions are shown to agree well with those obtained from the corresponding deterministic model. This approach to astrochemical kinetics should form the basis for realistic and accurate modeling of astrochemical processes that are inherently stochastic, such as grain surface reactions. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Charnley, Steven/C-9538-2012 NR 16 TC 47 Z9 47 U1 2 U2 2 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 DEC 20 PY 1998 VL 509 IS 2 BP L121 EP L124 DI 10.1086/311764 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800015 ER PT J AU Martin, EL Basri, G Brandner, W Bouvier, J Osorio, MRZ Rebolo, R Stauffer, J Allard, F Baraffe, I Hodgkin, ST AF Martin, EL Basri, G Brandner, W Bouvier, J Osorio, MRZ Rebolo, R Stauffer, J Allard, F Baraffe, I Hodgkin, ST TI Discovery of a very low mass binary with the Hubble Space Telescope near-infrared camera and multiobject spectrometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; open clusters and associations : individual (Pleiades); stars : evolution; stars : formation; stars : low-mass, brown dwarfs ID BROWN DWARFS; PLEIADES CLUSTER; CANDIDATES; SEQUENCE; LITHIUM; STARS AB Hubble Space Telescope Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations of six brown dwarf candidates in the Pleiades open cluster are presented. One of them, namely CFHT-Pl-18, is clearly resolved as a binary with an angular separation of 0".33. The very low density of contaminating background stars in our images and the photometry of the components support that this system is a physical binary rather than a chance projection. All of the available photometric and spectroscopic data indicate that the CFHT-Pl-18 system is likely a member of the Pleiades cluster, but a final confirmation will have to wait until lithium can be detected. Assuming cluster membership, we compare our NICMOS photometry with evolutionary models and find that the inclusion of the effects of dust grains is necessary for fitting the data. We estimate that the masses of the components are about 0.045 and 0.035 M.. The binary system has a projected separation of 42 AU (for a distance of 125 pc) that is common among stellar binaries. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Observ Grenoble, F-38041 Grenoble, France. Inst Astrofis Canarias, E-38200 La Laguna, Spain. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Ecole Normale Super Lyon, Ctr Rech Astron Lyon, F-69364 Lyon, France. Univ Leicester, Dept Phys & Astron, Astron Grp, Leicester LE1 7RH, Leics, England. RP Martin, EL (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Zapatero Osorio, Maria Rosa/C-2744-2017 OI Zapatero Osorio, Maria Rosa/0000-0001-5664-2852 NR 21 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP L113 EP L116 DI 10.1086/311775 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800013 ER PT J AU Michael, E McCray, R Pun, CSJ Borkowski, K Garnavich, P Challis, P Kirshner, RP Chevalier, R Filippenko, AV Fransson, C Panagia, N Phillips, M Schmidt, B Suntzeff, N Wheeler, JC AF Michael, E McCray, R Pun, CSJ Borkowski, K Garnavich, P Challis, P Kirshner, RP Chevalier, R Filippenko, AV Fransson, C Panagia, N Phillips, M Schmidt, B Suntzeff, N Wheeler, JC TI New Hubble Space Telescope observations of high-velocity Ly alpha and H alpha in SNR 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; shocks; supernova remnants ID X-RAY; SN-1987A AB We describe and model high-velocity (approximate to 15,000 km s(-1)) Ly alpha and H alpha emission from the supernova remnant SNR 1987A seen in 1997 September and October with the Space Telescope Imaging Spectrograph. Part of this emission comes from a reverse shock located at approximate to 75% of the radius of the inner boundary of the inner circumstellar ring and confined within +/- 30 degrees of the equatorial plane. Departure from axisymmetry in the Ly alpha and H alpha emission correlates with that seen in nonthermal radio emission and reveals an asymmetry in the circumstellar gas distribution. We also see diffuse high-velocity Ly alpha emission from supernova debris inside the reverse shock that may be due to excitation by nonthermal particles accelerated by the shock. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NASA, Lab Astron & Space Phys, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Stockholm Observ, S-13336 Saltsjobaden, Sweden. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Opt Astron Observ, Cerro Tololo Interamer Observ, La Serena, Chile. Mt Stromlo & Siding Spring Observ, Weston, ACT, Australia. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. RP Michael, E (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 11 TC 37 Z9 37 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP L117 EP L120 DI 10.1086/311780 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800014 ER PT J AU Sekanina, Z AF Sekanina, Z TI Modeling dust halos in comet Hale-Bopp (1995 O1): Existence of two active nuclei unequivocally implied SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (Hale-Bopp 1995 O1); methods : data analysis; techniques : image processing ID MORPHOLOGY AB The morphology of the comet's expanding, nearly concentric dust halos, which were observed extensively in 1997 February-April, is modeled by employing a Monte Carlo computer-simulation technique. A satisfactory model for the halos in late March requires only a slight correction to the spin-vector position determined previously from the diurnal evolution of a jet on February 28. A surprising result is the finding that, with this spin constraint, the halos observed in late February, only a few days before the jet, cannot be accounted for by ejecta from any combination of dust sources on the nucleus. Instead, the presence of a source on another nearby object-a second nucleus-is clearly implied. The spin vectors of the two nuclei are found to have subtended an angle greater than 90 degrees, but the tilt of their equatorial planes to the comet's heliocentric orbital plane may have practically been the same. Dust emission from the second nucleus is also shown to account for some of the fine jet features observed in late March. Thus, the existence of an active satellite nucleus, independent evidence for which was reported elsewhere, is strongly suggested by the comet's dust morphology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP L133 EP L136 DI 10.1086/311774 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800018 ER PT J AU Wang, QD Gotthelf, EV AF Wang, QD Gotthelf, EV TI ROSAT HRI detection of the 16 ms pulsar PSR J0537-6910 inside supernova remnant N157B SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; pulsars : individual (PSR J0537-6910); supernova remnants; X-rays : general ID RAY AB Based on a deep ROSAT HRI observation, we have detected a pulsed signal in the 0.1-2 keV band from PSR J0537-6910, the recently discovered pulsar associated with the supernova remnant N157B in the Large Magellanic Cloud. The measured pulse period 0.01611548182 s +/- 0.02 ns, epoch MJD 50,540.5, gives a revised linear spin-down rate of 5.1271 x 10(-14) s s(-1), which is slightly greater than the previously derived value. The narrow pulse shape (FWHM similar to 10% duty cycle) in the ROSAT band resembles those seen in both RXTE and ASCA data (greater than or similar to 2 keV), but there is also marginal evidence for an interpulse. This ROSAT detection enables us to locate the pulsar at R.A. = 5(h)37(m)47(s).2, decl. = -69 degrees 10'23" (J2000). With its uncertainty approximate to 3", this position coincides with the centroid of a compact X-ray source. But the pulsed emission accounts for only similar to 10% of the source luminosity of similar to 2 x 10(36) ergs(-1) in the 0.1-2 keV band. These results support our previous suggestions: (1) the pulsar is moving at a high velocity (similar to 10(3) km s(-1)); (2) a bow shock, formed around the pulsar, is responsible for most of the X-ray emission from the source; and (3) a collimated outflow from the bow shock region powers a pulsar wind nebula that accounts for an elongated nonthermal radio and X-ray feature to the northwest of the pulsar. C1 Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wang, QD (reprint author), Northwestern Univ, Dept Phys & Astron, 2145 Sheridan Rd, Evanston, IL 60208 USA. NR 5 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1998 VL 509 IS 2 BP L109 EP L112 DI 10.1086/311781 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DJ UT WOS:000079250800012 ER PT J AU Pickering, KE Wang, YS Tao, WK Price, C Muller, JF AF Pickering, KE Wang, YS Tao, WK Price, C Muller, JF TI Vertical distributions of lightning NOx for use in regional and global chemical transport models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID 10-11 JUNE 1985; MESOSCALE CONVECTIVE SYSTEM; SQUALL LINE; TOGA COARE; NUMERICAL SIMULATIONS; FREE TROPOSPHERE; PRE-STORM; MIDLATITUDE; THUNDERSTORMS; PRECIPITATION AB We have constructed profiles of lightning NOx mass distribution for use in specifying the effective lightning NOx source in global and regional chemical transport models. The profiles have been estimated for midlatitude continental, tropical continental, and tropical marine regimes based on profiles computed for individual storms in each regime. In order to construct these profiles we have developed a parameterization for lightning occurrence, lightning type, flash placement, and NOx production in a cloud-scale tracer transport model using variables computed in the two-dimensional Goddard Cumulus Ensemble (GCE) model. Wind fields from the GCE model are used to redistribute the lightning NOx throughout the duration of the storm. Our method produces reasonable results in terms of computed flash rates and NOx mixing ratios compared with observations. The profiles for each storm are computed by integrating the lightning NOx mass across the cloud model domain for each model layer at the end of the: storm. The results for all three regimes show a maximum in the mass profile in the upper troposphere, usually within 2-4 km of the tropopause. Downdrafts appear to be the strongest in the simulated midlatitude continental systems, evidenced by substantial lightning NOx mass (up to 23%) in the lowest kilometer. Tropical systems, particularly those over marine areas, tended to have a greater fraction of intracloud flashes and weaker downdrafts, causing only minor amounts of NOx to remain in the boundary layer following a storm. Minima appear in the profiles typically in the 2-5 km layer. Even though a substantial portion of the NOx is produced by cloud-to-ground flashes in the lowest 6 km, at the end of the storm most of the NOx is in the upper troposphere (55-75% above 8 km) in agreement with observations. With most of the effective lightning NOx source in the upper troposphere where the NOx lifetime is several days, substantial photochemical O-3 production is expected in this layer downstream of regions of deep convection containing lightning. We demonstrate that the effect on upper tropospheric NOx and O-3 is substantial when the vertical distribution of the lightning NOx source in a global model is changed from uniform to being specified by our profiles. Uncertainties in a number of aspects of our parameterization are discussed. C1 Univ Maryland, Dept Meteorol, Joint Ctr Earth Syst Sci, College Pk, MD 20742 USA. Belgian Inst Space Aeron, B-1180 Brussels, Belgium. Tel Aviv Univ, Dept Geophys & Planetary Sci, IL-69978 Ramat Aviv, Israel. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Greenbelt, MD USA. RP Pickering, KE (reprint author), Univ Maryland, Dept Meteorol, Joint Ctr Earth Syst Sci, College Pk, MD 20742 USA. EM pickerin@atmos.umd.edu; wang@carmen.gsfc.nasa.gov; tao@agnes.gsfc.nasa.gov; cprice@flash.tau.ac.il; Jean-Francois.Muller@bira-iasb.oma.be RI Pickering, Kenneth/E-6274-2012 NR 52 TC 255 Z9 260 U1 3 U2 27 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 DEC 20 PY 1998 VL 103 IS D23 BP 31203 EP 31216 DI 10.1029/98JD02651 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 154GM UT WOS:000077880800014 ER PT J AU Henning, T Salama, F AF Henning, T Salama, F TI Carbon - Carbon in the Universe SO SCIENCE LA English DT Review ID ULTRAVIOLET EXTINCTION CURVES; AMORPHOUS-CARBON; INTERSTELLAR CARBON; SILICON-CARBIDE; ELECTRONIC-STRUCTURE; AROMATIC-MOLECULES; ION IRRADIATION; GRAINS; GRAPHITE; DUST AB Carbon is a major player In the evolutionary scheme of the universe because of its abundance and its ability to form complex species. It is also a key element in the evolution of prebiotic molecules. The different forms of cosmic carbon are reviewed ranging from carbon atoms and carbon-bearing molecules to complex, solid-state, carbonaceous structures. The current state of knowledge is assessed an the observational and laboratory fronts. Fundamental astrophysical implications are examined as well as the impact of these studies on the hitherto poorly understood physical and chemical properties of carbon materials in space. C1 Inst Astrophys, D-07745 Jena, Germany. Univ Sternwarte, D-07745 Jena, Germany. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Henning, T (reprint author), Inst Astrophys, Schillergasschen 2-3, D-07745 Jena, Germany. RI Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 84 TC 212 Z9 226 U1 10 U2 74 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 DEC 18 PY 1998 VL 282 IS 5397 BP 2204 EP 2210 DI 10.1126/science.282.5397.2204 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150CR UT WOS:000077645800030 PM 9856936 ER PT J AU Muravyov, A AF Muravyov, A TI Forced vibration responses of a viscoelastic structure SO JOURNAL OF SOUND AND VIBRATION LA English DT Letter ID SYSTEMS C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP Muravyov, A (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 403,6 N Dryden St, Hampton, VA 23681 USA. NR 15 TC 19 Z9 21 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD DEC 17 PY 1998 VL 218 IS 5 BP 892 EP 907 DI 10.1006/jsvi.1998.1819 PG 16 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 147DJ UT WOS:000077472700009 ER PT J AU Zuber, MT Smith, DE Phillips, RJ Solomon, SC Banerdt, WB Neumann, GA Aharonson, O AF Zuber, MT Smith, DE Phillips, RJ Solomon, SC Banerdt, WB Neumann, GA Aharonson, O TI Shape of the northern hemisphere of Mars from the Mars Orbiter Laser Altimeter (MOLA) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Eighteen profiles of similar to N-S-trending topography from the Mars Orbiter Laser Altimeter (MOLA) are used to analyze the shape of Mars' northern hemisphere. MOLA observations show smaller northern hemisphere flattening than previously thought. The hypsometric distribution is narrowly peaked with > 20% of the surface lying within 200 m of the mean elevation. Low elevation correlates with low surf-ice roughness, but the elevation and roughness may reflect different mechanisms. Bouguer gravity indicates less variability in crustal thickness and/or lateral density structure than previously expected. The 3.1-km offset between centers of mass and figure along the polar axis results in a pole-to-equator slope at all longitudes. The N-S slope distribution also shows a subtle longitude-dependent variation that may represent the antipodal effect of the formation of Tharsis. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. RP Zuber, MT (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RI Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 14 TC 19 Z9 19 U1 0 U2 4 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 DEC 15 PY 1998 VL 25 IS 24 BP 4393 EP 4396 DI 10.1029/1998GL900129 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600001 ER PT J AU Smith, DE Zuber, MT AF Smith, DE Zuber, MT TI The relationship between MOLA northern hemisphere topography and the 6.1-Mbar atmospheric pressure surface of Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIO OCCULTATION MEASUREMENTS; MARINER-9; POLAR AB To assist in targeting of landers and to enable comparison of new elevation data to previous topography models, we have re-determined the position of the 6.1-mbar atmospheric pressure surface on Mars with respect to surface topography from the Mars Orbiter Laser Altimeter (MOLA). The 6.1-mbar surface lies, on average, 1600 m below the geoid-defined zero level of MOLA topography, which occurs at an average pressure of 5.2 mbars at L-S=0 degrees. The elevation of the 6.1-mbar surface is expected to vary by 1.5-2.5 km over the Martian year due to the seasonal exchange of CO2 between the atmosphere and polar caps. For average Martian atmospheric conditions, the pressure at the Mars Surveyor '98 landing site is expected to be similar to 5.0 mbars during the lander science phase of the mission assuming an elevation of 1600 meters above the zero level defined by MOLA topography. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Smith, DE (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 920, Greenbelt, MD 20771 USA. NR 25 TC 32 Z9 32 U1 1 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 DEC 15 PY 1998 VL 25 IS 24 BP 4397 EP 4400 DI 10.1029/1998GL900085 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600002 ER PT J AU Head, JW Kreslavsky, M Hiesinger, H Ivanov, M Pratt, S Seibert, N Smith, DE Zuber, MT AF Head, JW Kreslavsky, M Hiesinger, H Ivanov, M Pratt, S Seibert, N Smith, DE Zuber, MT TI Oceans in the past history of Mars: Tests for their presence using Mars Orbiter Laser Altimeter (MOLA) data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB An ancient north polar ocean on Mars has been proposed [Parker et al., 1989] and we use MOLA data to test the hypothesis. Of the two proposed contacts/shorelines, the younger Contact 2 shows the closest approximation to an equipotential surface; vertical variations along this surface occur in areas with post-contact-formation geological activity or suspected changes in the position of an equipotential surface (e.g., Tharsis) with time. The surface of Mars is smoother at all scales below Contact 2 than above. The volume of the region below Contact 2 (similar to 1.5 x 10(7) km(3)) is between the minimum estimated total outflow channel discharge and the maximum estimated megaregolith pore space. These results are consistent with the hypothesis that a large standing body of water occupied the northern lowlands in the past history of Mars. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Head, JW (reprint author), Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. RI Kreslavsky, Mikhail/J-3425-2013; OI Kreslavsky, Mikhail/0000-0002-1900-826X NR 13 TC 81 Z9 81 U1 1 U2 4 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 DEC 15 PY 1998 VL 25 IS 24 BP 4401 EP 4404 DI 10.1029/1998GL900116 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600003 ER PT J AU Garvin, JB Frawley, JJ AF Garvin, JB Frawley, JJ TI Geometric properties of Martian impact craters: Preliminary results from the Mars Orbiter Laser Altimeter SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EJECTA; WATER; ICE AB The Mars Orbiter Laser Altimeter (MOLA) acquired high spatial and vertical resolution topographic data for 18 tracks across the northern hemisphere of Mars during the Fall of 1997. It sampled 98 minimally degraded impact craters between the latitudes of 80 degrees N and 12 degrees S The best fitting depth (d) versus diameter (D) power-law relationship for these craters is: d = 0.14 D-0.90 for Simple varieties, and d = 0.25 D-0.49 for complex structures. The simple-to-complex transition diameter is 8 km (+/- 0.5 km). The cross-sectional "shape" of the crater cavities was determined by fitting a power-function to each profile. Variation in the exponent (n) suggest the craters flatten with increasing diameter and impact energy. The ejecta thickness is skewed suggesting that use of existing empirical expressions for the expected radial decay of ejecta thickness is inappropriate for Mars in most cases. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Herring Bay Geophys, Tracys Landing, MD 20799 USA. RP Garvin, JB (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 921, Greenbelt, MD 20771 USA. NR 18 TC 59 Z9 59 U1 1 U2 5 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 DEC 15 PY 1998 VL 25 IS 24 BP 4405 EP 4408 DI 10.1029/1998GL900177 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600004 ER PT J AU Frey, H Sakimoto, SE Roark, J AF Frey, H Sakimoto, SE Roark, J TI The MOLA topographic signature at the crustal dichotomy boundary zone on Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ORIGIN AB MOLA data collected during the aerobraking hiatus provide good longitudinal sampling of the crustal dichotomy boundary zone in eastern Mars and reveal a significant topographic signature associated with the transition from cratered highlands to lowland plains. Total relief between the two major units is always >2.5 km and sometimes >6 km; median elevation differences are about 4 km. Regional slopes are very low (< 0.02 degrees) in both cratered terrain south and in lowland plains north of the boundary. Within the transition zone where cratered terrain changes to detached plateaus, mesas and knobby terrain, slopes are 50-100 times steeper and over a few hundred kilometers average about 1 degrees. The topographic signature of the boundary zone is best described as a 2-4 km step function between two nearly flat surfaces, similar in slope and amplitude to some terrestrial passive margins. This supports previous conclusions of a significant difference in crustal properties (thickness, composition, or both) between the lowland plains and cratered terrain, and suggests this difference occurs over a relatively short distance of a few to several hundred kilometers. C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Geodynam Branch, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Sci Syst & Appl Inc, Lanham, MD USA. RP Frey, H (reprint author), NASA, Goddard Space Flight Ctr, Geodynam Branch, Code 921, Greenbelt, MD 20771 USA. EM frey@denali.gsfc.nasa.gov; sakimoto@denali.gsfc.nasa.gov; roark@denali.gsfc.nasa.gov NR 13 TC 31 Z9 31 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 DEC 15 PY 1998 VL 25 IS 24 BP 4409 EP 4412 DI 10.1029/1998GL900095 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600005 ER PT J AU Aharonson, O Zuber, MT Neumann, GA Head, JW AF Aharonson, O Zuber, MT Neumann, GA Head, JW TI Mars: Northern hemisphere slopes and slope distributions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VENUS AB We investigate slope distributions in the northern hemisphere of Mars from topographic profiles collected by the Mars Orbiter Laser Altimeter. Analysis of the region from about 12 degrees S to 82 degrees N, over diverse geologic units, indicates that the range of regional-scale slopes is small, generally < 3 degrees. Surface smoothness is most distinctive in the vast northern hemisphere plains, where slopes are typically < 1 degrees. Amazonis Planitia is particularly remarkable in its smoothness, exhibiting an rms variation in topography of < 2 m over a 100-km baseline. This relative smoothness is still present when compared with other sampled areas of the Martian northern hemisphere and with volcanically resurfaced terrains elsewhere in the solar system. Planetary surfaces of large areal extent that are most comparable to Amazonis in terms of rms elevation variation over long baselines are depositional in origin and include terrestrial oceanic abyssal plains and certain sedimentary basins. Slopes across the Valles Marineris canyon system show that the upper portion of the walls are significantly and consistently steeper than the lower walls, characteristic of extensive mass wasting. The observed long-runout is consistent with a high-energy collapsed flow. In the neighboring Noctis Labyrinthus canyons the duality between the upper and lower walls is reduced, and indicates a lower energy modificational history and/or greater cohesion of wall rock. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Aharonson, O (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RI Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 17 TC 34 Z9 37 U1 1 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 DEC 15 PY 1998 VL 25 IS 24 BP 4413 EP 4416 DI 10.1029/1998GL900057 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600006 ER PT J AU Domingue, DL Lane, AL AF Domingue, DL Lane, AL TI IUE views Europa: Temporal variations in the UV SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GALILEAN SATELLITES; ABSORPTION-BAND; REFLECTANCE; BOMBARDMENT; SURFACE; SPECTRA; FROST; WATER; NM AB Observations taken with the International Ultraviolet Explorer (IUE) show the first detection of temporal changes in the UV spectral reflectance of the Jovian quadrant of Europa's leading side between 15 degrees-75 degrees longitude over a time scale considered extraordinarily short for a large planetary object (commensurate with possible resurfacing events). The central trailing side region displays a 0.28 mu m SO2 absorption that has remained constant in relative depth over the past decade to within the instrument detection limits. A new 0.33 mu m absorption feature is seen on the leading side. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Domingue, DL (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 27 TC 13 Z9 13 U1 0 U2 0 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 DEC 15 PY 1998 VL 25 IS 24 BP 4421 EP 4424 DI 10.1029/1998GL900209 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600008 ER PT J AU Cane, HV Richardson, IG von Rosenvinge, TT AF Cane, HV Richardson, IG von Rosenvinge, TT TI Interplanetary magnetic field periodicity of similar to 153 days SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR; FLARES AB We report on the finding of a 153-day periodicity in the magnetic field strength and solar wind speed measured at 1 AU during the years 1978-1982. The period and the occurence epoch are consistent with the "154-day" periodicity previously reported for events occurring at the Sun. In particular, the variations in the field strength and the occurence rate of energetic (tens of MeV) solar particle events are in phase. The similar periodicities in the interplanetary field and solar phenomena are consistent with a global phenomenon. Whereas this periodicity is quite strong for the magnetic field magnitude, there is only a weak periodicity for the individual field components. The field magnitude shows essentially no periodicity at this period during the previous and following solar maxima. The lack of persistence, and of significant harmonic components of the observed periodicity, does not support the proposal of a solar "clock" mechanism. The most significant variations in the complete near-earth magnetic field data base (1963-1997) with periods of less than 200 days occur at 166 and 146 days. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas, Australia. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Cane, HV (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. OI Richardson, Ian/0000-0002-3855-3634 NR 13 TC 41 Z9 45 U1 0 U2 0 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 DEC 15 PY 1998 VL 25 IS 24 BP 4437 EP 4440 DI 10.1029/1998GL900208 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600012 ER PT J AU Levelt, PF Khattatov, BV Gille, JC Brasseur, GP Tie, XX Waters, JW AF Levelt, PF Khattatov, BV Gille, JC Brasseur, GP Tie, XX Waters, JW TI Assimilation of MLS ozone measurements in the global three-dimensional chemistry transport model ROSE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERE AB A method for assimilating observations of ozone was implemented in the three-dimensional global stratospheric chemistry transport model ROSE. The model contains an extensive photochemical scheme which includes heterogeneous chemistry and uses temperature and wind fields from the UKMO (United Kingdom Meteorological Office) stratospheric analysis. Ozone measurements obtained by the Microwave Limb Sounder (MLS) on board the Upper Atmosphere Research Satellite (UARS) were assimilated in the model using the sequential statistical interpolation approach. The analysis is performed using a time invariant background error covariance matrix that only includes horizontal covariances. Results from a sixty day simulation are presented and it is shown that assimilation of the MLS observations results in improved global three-dimensional distributions of ozone as seen from comparisons with MLS data not assimilated in the model. For further validation, the stratospheric total ozone fields computed from the analysis are compared with the TOVS total ozone measurements and it is shown that they agree within the uncertainty of the data. C1 Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Levelt, PF (reprint author), Royal Netherlands Meteorol Inst, POB 201, NL-3730 AE De Bilt, Netherlands. NR 9 TC 38 Z9 38 U1 1 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 DEC 15 PY 1998 VL 25 IS 24 BP 4493 EP 4496 DI 10.1029/1998GL900152 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600026 ER PT J AU Fujiwara, S Yarai, H Ozawa, S Tobita, M Murakami, M Nakagawa, H Nitta, K Rosen, PA Werner, CL AF Fujiwara, S Yarai, H Ozawa, S Tobita, M Murakami, M Nakagawa, H Nitta, K Rosen, PA Werner, CL TI Surface displacement of the March 26, 1997 Kagoshima-kenhokuseibu earthquake in Japan from synthetic aperture radar interferometry SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LANDERS EARTHQUAKE; DEFORMATION; CALIFORNIA AB A JERS 1 differential L-band synthetic aperture radar (SAR) interferogram of the March 26, 1997 Kagoshimaken-hokuseibu earthquake (M-w=6.1) in southwestern Japan shows about 9 cm peak-to-peak coseismic surface displacement in the radar line-of-sight (LOS) direction. A permanent GPS array detected 1 to 2 cm horizontal displacements from this earthquake. By inverting the SAR and GPS data together, we estimated a fault mechanism without any seismological data. A theoretical radar LOS displacement pattern from a single fault model of the earthquake motion matches the SAR and GPS observations closely. The model assumes left lateral slip of 0.46 cm with rake angle of 19 degrees on a rectangular fault plane of dimensions 11 km (width) by 12 km (length). We demonstrate that L-band SAR interferometry can describe several cm surface displacement in detail and construct a fault model. However, despite the acquisitions being during the cold season, there are apparent water vapor signatures in the interferogram with equivalent path delays of up to 1.5 cm. C1 Geog Survey Inst, Tsukuba, Ibaraki 3050811, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fujiwara, S (reprint author), Geog Survey Inst, Kitasato 1, Tsukuba, Ibaraki 3050811, Japan. NR 17 TC 14 Z9 15 U1 0 U2 0 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 DEC 15 PY 1998 VL 25 IS 24 BP 4541 EP 4544 DI 10.1029/1998GL900191 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 154HD UT WOS:000077882600038 ER PT J AU Bauer, S Swenson, MS Griffa, A Mariano, AJ Owens, K AF Bauer, S Swenson, MS Griffa, A Mariano, AJ Owens, K TI Eddy mean flow decomposition and eddy-diffusivity estimates in the tropical Pacific Ocean 1. Methodology SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID EQUATORIAL PACIFIC; SURFACE CURRENTS; VARIABILITY; TURBULENCE; CIRCULATION; DISPERSION; DRIFTERS; VELOCITY; FIELDS AB The tropical Pacific Ocean surface current system can be characterized by a strong degree of nonstationarity due to the fast response time of equatorial and near-equatorial dynamics. The ocean-atmospheric dynamics create longitudinally coherent zonal flow (zonal length scales l(x) similar to 60 degrees) with strong meridional shear (l(y) similar to 1 degrees in latitude) in the large-scale mean and an energetic mesoscale (O(100 km)) component. Parameterization of the effects of the mesoscale field depends on the separation of the large-scale mean from the observed velocity. In this paper the focus is placed on the key issue: separating the flow into large-scale mean and mesoscale eddy components in order to compute meaningful eddy diffusivity estimates in flow regimes that demonstrate strong currents and strong shear. Large gradients in the large-scale mean have precluded diffusivity estimation by traditional binning techniques. In this first of two publications, a method is developed for using Lagrangian data to estimate the diffusivity addressing the inhomogeneity of the mean flow. The spatially dependent estimate of the mean field is computed with a least squares bicubic smoothing spline interpolation scheme with an optimized roughness parameter which guarantees minimum energy in the fluctuation field at low frequencies. Numerical simulations based on a stochastic model of a turbulent shear flow are used to validate our approach in a conceptually simple but realistic scenario. The technique is applied to near-surface drifter observations obtained from 1979-1946 from two dynamically distinct time-space regions of the tropical Pacific Ocean. The first region, in the South Equatorial Current, is characterized by a linear zonal shear mean flow and an approximately exponential autocovariance structure in the residuals. The velocity residuals have velocity variance of (s) over cap(2) = 130 cm(2) s(-2) for both components, and horizontal diffusivities are <(kappa)over cap>(u) approximate to 7 X 10(7) cm(2) s(-1) and <(kappa)over cap>(v) approximate to 3 X 10(7) cm(2) s(-1). No significant interannual variations of the estimates are detected, but residual trends in the estimators arise from intraseasonal variations in the velocity field during the 3-month season. The second region, in the North Equatorial Countercurrent and the North Equatorial Current, has a mean flow with a strong zonal shear and a weak northward velocity. The autocovariance is approximately exponential for the zonal component, while the meridional component has a negative lobe at about 10 days, probably due to the presence of instability waves. The variance is 380 cm(2) s(-2) for the zonal component and 360 cm(2) s(-2) for the meridional component, while the horizontal diffusivities are <(kappa)over cap>(u) approximate to 15 X 10(7) cm(2) s(-1) and <(kappa)over cap>(v) approximate to 4 X 10(7) cm(2) s(-1). Strong intraseasonal variability requires a maximum time window of 2 months for approximate stationarity to hold for the covariance calculations. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Bauer, S (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. EM swenson@aoml.erl.gov NR 30 TC 74 Z9 74 U1 3 U2 7 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 DEC 15 PY 1998 VL 103 IS C13 BP 30855 EP 30871 DI 10.1029/1998JC900009 PG 17 WC Oceanography SC Oceanography GA 155YR UT WOS:000077974900015 ER PT J AU Nazarenko, L Holloway, G Tausnev, N AF Nazarenko, L Holloway, G Tausnev, N TI Dynamics of transport of "Atlantic signature" in the Arctic Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TOPOGRAPHIC STRESS; SEA ICE; GENERAL-CIRCULATION; MODEL; WATER; PARAMETERIZATION; ALGORITHMS; BASIN AB Understanding the circulation of the Arctic is the basis for considering questions relating to transport of contaminants from all sources. In this study a numerical ice-ocean model has been used to address problems of the dispersion and transport pathways of contaminants in the water column. We investigate sensitivity of the contaminant distribution to parameterization of sub-grid-scale eddies and to numerical representation of tracer advection. An implementation of flux-corrected transport helps preserve tracer properties along their advective paths. Eddy parameterization is found to be important insofar as eddy-topography interactions contribute to propelling and sustaining narrow boundary currents. These boundary currents, cyclonic around the Arctic and each of its subbasins, are the main vehicle that transports Atlantic water properties. Consideration of ice and ocean models together does not lead to significant alterations in distribution of Atlantic properties. Although inclusion of sea ice affects circulation of the upper (halocline) layers, the main transport of Atlantic properties occurs in deeper layers, which are much less affected by ice processes. C1 Fisheries Oceans Canada Inst Ocean Sci, Sidney, BC V8L 4B2, Canada. Inst No Ecol Problems, Apatity 184200, Russia. RP Columbia Univ, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM lnazarenko@giss.nasa.gov NR 53 TC 41 Z9 41 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 1998 VL 103 IS C13 BP 31003 EP 31015 DI 10.1029/1998JC900017 PG 13 WC Oceanography SC Oceanography GA 155YR UT WOS:000077974900023 ER PT J AU Hribar, MR Taylor, VE Boyce, DE AF Hribar, MR Taylor, VE Boyce, DE TI Termination detection for parallel shortest path algorithms SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article DE parallel shortest path; idle time; synchronization; termination detection AB Shortest path computation is required by a large number of applications such as VLSI, transportation, and communication networks. These applications, which are often. very complex and have sparse networks, generally use parallel labeling shortest path algorithms. Such algorithms, when implemented on a distributed memory machine, require termination detection methods; these methods consist of some type of synchronization among all processors. Because global synchronization can be costly, it is assumed that the best termination detection methods synchronize as infrequently as possible. The frequency, however, can significantly impact the idle time of parallel labeling shortest path algorithms. In this paper we analyze the impact of this frequency on the performance, in particular the idle time, and identify when low versus high frequency detection is best. The analysis and results indicate that when the size of the subnetwork assigned to processor is small enough so that the computation time is less than or equal to the communication time within an iteration, high frequency termination detection methods should be used. Otherwise, low frequency methods should be used. (C) 1998 Academic Press. C1 Univ Illinois, Dept Civil & Mat Engn, Chicago, IL 60607 USA. Northwestern Univ, ECE Dept, Evanston, IL 60208 USA. RP Hribar, MR (reprint author), NASA, MRJ Technol Solut Inc, Ames Res Ctr, MS T27A-2, Moffett Field, CA 94035 USA. NR 15 TC 6 Z9 7 U1 0 U2 0 PU ACADEMIC PRESS INC 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 DEC 15 PY 1998 VL 55 IS 2 BP 153 EP 165 DI 10.1006/jpdc.1998.1502 PG 13 WC Computer Science, Theory & Methods SC Computer Science GA 159GC UT WOS:000078162900001 ER PT J AU Quijada, M Cerne, J Simpson, JR Drew, HD Ahn, KH Millis, AJ Shreekala, R Ramesh, R Rajeswari, M Venkatesan, T AF Quijada, M Cerne, J Simpson, JR Drew, HD Ahn, KH Millis, AJ Shreekala, R Ramesh, R Rajeswari, M Venkatesan, T TI Optical conductivity of manganites: Crossover from Jahn-Teller small polaron to coherent transport in the ferromagnetic state SO PHYSICAL REVIEW B LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; DOUBLE-EXCHANGE; ELECTRONIC-STRUCTURE; THIN-FILMS; LA1-XSRXMNO3; TRANSITION; LA1-XCAXMNO3; LOCALIZATION; RESISTIVITY; SPECTRA AB We report on the optical properties of the hole-doped manganites Nd0.7Sr0.3MnO3, La0.7Ca0.3MnO3, and La0.7Sr0.3MnO3. The low-energy optical conductivity in the paramagnetic-insulating state of these materials is characterized by a broad maximum near 1 eV. This feature shifts to lower energy and grows in optical oscillator strength as the temperature is lowered into the ferromagnetic state. It remains identifiable well below T-c and transforms eventually into a Drude-like response. This optical behavior and the activated transport in the paramagnetic state of these materials are consistent with a Jahn-Teller small polaron. The optical spectra and oscillator strength changes compare well with models that include both double exchange and the dynamic Jahn-Teller effect in the description of the electronic structure. [S0163-1829(98)06848-9]. C1 Lab Phys Sci, College Pk, MD 20740 USA. Univ Maryland, Dept Phys, Mat Res Lab, College Pk, MD 20742 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Quijada, M (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 45 TC 175 Z9 176 U1 3 U2 21 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 DEC 15 PY 1998 VL 58 IS 24 BP 16093 EP 16102 DI 10.1103/PhysRevB.58.16093 PG 10 WC Physics, Condensed Matter SC Physics GA 151BE UT WOS:000077700400030 ER PT J AU Berera, A Gleiser, M Ramos, RO AF Berera, A Gleiser, M Ramos, RO TI Strong dissipative behavior in quantum field theory SO PHYSICAL REVIEW D LA English DT Article ID ELECTROWEAK PHASE-TRANSITION; FINITE-TEMPERATURE; EARLY UNIVERSE; SCALAR FIELD; EVOLUTION EQUATION; HIGGS FIELD; SUBCRITICAL BUBBLES; THERMAL-EQUILIBRIUM; EXPANDING UNIVERSE; REAL-TIME AB We study the conditions under which an overdamped regime can be attained in the dynamic evolution of a quantum field configuration. Using a real-time formulation of finite temperature field theory, we compute the effective evolution equation of a scalar field configuration, quadratically interacting with a given set of other scalar fields. We then show that, in the overdamped regime, the dissipative kernel in the field equation of motion is closely related to the shear viscosity coefficient, as computed in scalar field theory at finite temperature. The effective dynamics is equivalent to a time-dependent Ginzburg-Landau description of the approach to equilibrium in phenomenological theories of phase transitions. Applications of our results, including a recently proposed inflationary scenario called "warm inflation," are discussed. [S0556-2821(98)03474-5]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Osservatorio Astron Roma, I-00136 Rome, Italy. Univ Estado Rio de Janeiro, Inst Fis, Dept Fis Teor, BR-20550013 Rio De Janeiro, Brazil. RP Berera, A (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. EM berera@vuhep.phy.vanderbilt.edu; gleiser@peterpan.dartmouth.edu; rudnei@symbcomp.uerj.br RI Ramos, Rudnei/C-4492-2008 OI Ramos, Rudnei/0000-0001-8781-4928 NR 61 TC 140 Z9 141 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 1998 VL 58 IS 12 AR 123508 DI 10.1103/PhysRevD.58.123508 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 154RR UT WOS:000077903000019 ER PT J AU Kinney, WH AF Kinney, WH TI Constraining inflation with cosmic microwave background polarization SO PHYSICAL REVIEW D LA English DT Article ID COSMOLOGICAL PARAMETERS; ANISOTROPY EXPERIMENTS; DENSITY PERTURBATIONS; TENSOR PERTURBATIONS; SYMMETRY-BREAKING; UNIVERSE SCENARIO; MODELS; SCALE; SPECTRUM; RADIATION AB Observations of the polarization of the cosmic microwave backround (CMB) have the potential to place much tighter constraints on cosmological parameters than observations of the fluctuations in temperature alone. We discuss using CMB polarization to constrain parameters relevant for distinguishing among popular models for cosmological inflation, using the MAP and Planck satellite missions as example cases. Of particular interest is the ability to detect tiny contributions to the CMB anisotropy from tensor modes, which is fundamentally limited by cosmic variance in temperature-only observations. The ability to detect a tensor/scalar ratio r similar to 0.01 would allow precision tests of interesting inflation models, and is possible with a modest increase in sensitivity over that planned for the Planck satellite or is potentially achievable by ground-based experiments. [S0556-2821(98)01822-0]. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Kinney, WH (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM kinneyw@fnal.gov NR 60 TC 81 Z9 81 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 1998 VL 58 IS 12 AR 123506 DI 10.1103/PhysRevD.58.123506 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 154RR UT WOS:000077903000017 ER PT J AU Kogej, T Beljonne, D Meyers, F Perry, JW Marder, SR Bredas, JL AF Kogej, T Beljonne, D Meyers, F Perry, JW Marder, SR Bredas, JL TI Mechanisms for enhancement of two-photon absorption in donor-acceptor conjugated chromophores SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NONLINEAR-OPTICAL-PROPERTIES; 2-PHOTON ABSORPTION; POLARIZATION; EXCITATION; POLYENES; STORAGE AB Two-photon absorption (TPA) is a nonlinear optical process that is gaining increasing attention since it can be exploited in a number of optical applications. Here, on the basis of correlated quantum-chemical calculations, we investigate the structure-TPA property relationships for donor-acceptor pi-conjugated compounds. These relationships provide strategies to design dyes with large TPA cross-sections for fundamental photon wavelengths in the desired 0.6-1.0 mu m range of wavelengths. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Mons, Ctr Res Mol Elect & Photon, Lab Chem Novel Mat, B-7000 Mons, Belgium. CALTECH, Beckman Inst, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bredas, JL (reprint author), Univ Mons, Ctr Res Mol Elect & Photon, Lab Chem Novel Mat, Pl Parc 20, B-7000 Mons, Belgium. EM jeanluc@averell.umh.ac.be RI Bredas, Jean-Luc/A-3431-2008; Perry, Joseph/B-7191-2011 OI Bredas, Jean-Luc/0000-0001-7278-4471; Perry, Joseph/0000-0003-1101-7337 NR 21 TC 268 Z9 274 U1 5 U2 36 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 11 PY 1998 VL 298 IS 1-3 BP 1 EP 6 DI 10.1016/S0009-2614(98)01196-8 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 149LX UT WOS:000077607700001 ER PT J AU Zuber, MT Smith, DE Solomon, SC Abshire, JB Afzal, RS Aharonson, O Fishbaugh, K Ford, PG Frey, HV Garvin, JB Head, JW Ivanov, AB Johnson, CL Muhleman, DO Neumann, GA Pettengill, GH Phillips, RJ Sun, ZL Zwally, HJ Banerdt, WB Duxbury, TC AF Zuber, MT Smith, DE Solomon, SC Abshire, JB Afzal, RS Aharonson, O Fishbaugh, K Ford, PG Frey, HV Garvin, JB Head, JW Ivanov, AB Johnson, CL Muhleman, DO Neumann, GA Pettengill, GH Phillips, RJ Sun, ZL Zwally, HJ Banerdt, WB Duxbury, TC TI Observations of the north polar region of Mars from the Mars Orbiter Laser Altimeter SO SCIENCE LA English DT Article ID PLANETARY CONDITIONS; WATER-VAPOR; ICE; BEHAVIOR; MODEL AB Elevations from the Mars Orbiter Laser Altimeter (MOLA) have been used to construct a precise topographic map of the martian north polar region. The northern ice cap has a maximum elevation of 3 kilometers above its surroundings but Lies within a 5-kilometer-deep hemispheric depression that is contiguous with the area into which most outflow channels emptied, Polar cap topography displays evidence of modification by ablation, flow, and wind and is consistent with a primarily H2O composition. Correlation of topography with images suggests that the cap was more spatially extensive in the past. The cap volume of 1.2 x 10(6) to 1.7 x 10(6) cubic kilometers is about half that of the Greenland ice cap. Clouds observed over the polar cap are Likely composed of CO2 that condensed out of the atmosphere during northern hemisphere winter. Many clouds exhibit dynamical structure Likely caused by the interaction of propagating wave fronts with surface topography. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Earth Sci Directorate, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. CALTECH, Pasadena, CA 91125 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zuber, MT (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RI Sun, Xiaoli/B-5120-2013; Abshire, James/I-2800-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 49 TC 188 Z9 188 U1 3 U2 16 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 DEC 11 PY 1998 VL 282 IS 5396 BP 2053 EP 2060 DI 10.1126/science.282.5396.2053 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 147BB UT WOS:000077467100040 PM 9851922 ER PT J AU George, IM Mushotzky, R Turner, TJ Yaqoob, T Ptak, A Nandra, K Netzer, H AF George, IM Mushotzky, R Turner, TJ Yaqoob, T Ptak, A Nandra, K Netzer, H TI The X-ray spectral variability of the Seyfert galaxy NGC 3227 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3227); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; ASCA OBSERVATIONS; CIRCUMNUCLEAR REGION; WARM ABSORBER; NGC-3227; EMISSION; ABSORPTION; LINE; COMPTONIZATION; ULTRAVIOLET AB We present the results from ASCA observations of NGC 3227 performed during 1993 and 1995, along with those from a ROSAT observation performed pseudosimultaneously with the former. We find the 0.6-10 keV continuum to be consistent with a power law with a photon index Gamma similar to 1.6, flatter than that typically observed in Seyfert galaxies confirming previous results. Significant Fe K-shell emission is observed during both epochs, with an equivalent width and profile typical of Seyfert 1 galaxies. The ASCA observations in 1993 reveal absorption by a screen N-H,z(ion) similar or equal to 3 x 10(21) cm(-2) of ionized material with an X-ray ionization parameter U-X similar or equal to 0.01. Both the column and ionization state of this material are at the low end of the distribution of parameters observed for Seyfert I galaxies. Joint analysis of the ASCA and ROSAT data at this epoch shows an additional screen of neutral material instrinsic to NGC 3227 with N-H,z(neu) similar to few x 10(20) cm(-2). We find NGC 3227 to exhibit significant spectral variability both within and between the observations. The most likely explanation involves short-term variability in the continuum emission and longer term variability in the column density of the ionized material. Time-resolved spectroscopy and color-color analysis indicate that the slope of the continuum steepened by Delta Gamma similar or equal to 0.1 during a hare of duration similar to 10(4) s, within the 1993 observation. However, we were unable to distinguish between a steepening of the "primary" continuum and a change in the relative strengths of the power law and a putative Compton-reflection component. The absorbing column increased by a factor of similar to 10 by the 1995 epoch, while the continuum is consistent with that observed in 1993. The 1995 data also show evidence that the warm absorber allows similar to 10% of the nuclear emission to escape without attenuation. We review our findings in the context of the previous results from this and similar objects and discuss the prospects of future observations. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Wise Observ, IL-69978 Tel Aviv, Israel. RP George, IM (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Ptak, Andrew/D-3574-2012 NR 73 TC 29 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP 146 EP 162 DI 10.1086/306477 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400015 ER PT J AU O'Brien, PT Dietrich, M Leighly, K Alloin, D Clavel, J Crenshaw, DM Horne, K Kriss, GA Krolik, JH Malkan, MA Netzer, H Peterson, BM Reichert, GA Rodriguez-Pascual, PM Wamsteker, W Anderson, KSJ Bochkarev, NG Cheng, FZ Filippenko, AV Gaskell, CM George, IM Goad, MR Ho, LC Kaspi, S Kollatschny, W Korista, KT MacAlpine, G Marlow, D Martin, PG Morris, SL Pogge, RW Qian, BC Recondo-Gonzalez, MC Espinosa, JMR Santos-Lleo, M Shapovalova, AI Shull, JM Stirpe, GM Sun, WH Turner, TJ Vio, R Wagner, S Wanders, I Wills, KA Wu, H Xue, SJ Zou, ZL AF O'Brien, PT Dietrich, M Leighly, K Alloin, D Clavel, J Crenshaw, DM Horne, K Kriss, GA Krolik, JH Malkan, MA Netzer, H Peterson, BM Reichert, GA Rodriguez-Pascual, PM Wamsteker, W Anderson, KSJ Bochkarev, NG Cheng, FZ Filippenko, AV Gaskell, CM George, IM Goad, MR Ho, LC Kaspi, S Kollatschny, W Korista, KT MacAlpine, G Marlow, D Martin, PG Morris, SL Pogge, RW Qian, BC Recondo-Gonzalez, MC Espinosa, JMR Santos-Lleo, M Shapovalova, AI Shull, JM Stirpe, GM Sun, WH Turner, TJ Vio, R Wagner, S Wanders, I Wills, KA Wu, H Xue, SJ Zou, ZL TI Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. XIII. Ultraviolet observations of the broad-line radio galaxy 3C 390.3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (3C 390.3); ultraviolet : galaxies ID SHORT-TIMESCALE VARIABILITY; MULTIWAVELENGTH OBSERVATIONS; X-RAY; EMISSION-LINES; OPTICAL WAVELENGTHS; ACCRETION DISKS; UV CONTINUUM; NGC-5548; NGC-4151; 3C-390.3 AB As part of an extensive multiwavelength monitoring campaign, the Inter national Ultraviolet Explorer satellite was used to observe the broad-line radio galaxy 3C 390.3 during the period 1994 December 31-1996 March 5. Spectra were obtained every 6-10 days. The UV continuum varied by a factor of 7 through the campaign, while the broad emission lines varied by factors of 2-5. Unlike previously monitored Seyfert 1 galaxies, in which the X-ray continuum generally varies with a larger amplitude than the UV, in 3C 390.3 the UV continuum light curve is similar in both amplitude and shape to the X-ray light curve observed by ROSAT. The UV broad emission-line variability lags that of the UV continuum by 35-70 days for Ly alpha and C rv, values larger than those found for Seyfert 1 galaxies of comparable UV luminosity. These lags are also larger than those found for the Balmer lines in 3C 390.3 over the same period. The red and blue wings of C rv and Ly alpha vary in phase, suggesting that radial motion does not dominate the kinematics of the UV line-emitting gas. Comparison with archival data provides evidence for velocity-dependent changes in the Ly alpha and C rv line profiles, indicating evolution in the detailed properties and/or distribution of the broad-line emitting gas. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Landessternwarte, D-69117 Heidelberg, Germany. Columbia Univ, Astrophys Lab, New York, NY 10027 USA. Ctr Etud Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. European Space Agcy, ISO Project, Madrid 28080, Spain. NASA, Goddard Space Flight Ctr, Comp Sci Corp, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KYI16 9SS, Fife, Scotland. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90024 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Wise Observ, IL-69978 Tel Aviv, Israel. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ESA IUE Observ, Madrid 28080, Spain. New Mexico State Univ, Dept Astron, Dept 4500, Las Cruces, NM 88003 USA. Moscow MV Lomonosov State Univ, Sternberg Astron Inst, Moscow 119899, Russia. Univ Sci & Technol, Ctr Astrophys, Hefei, Anhui, Peoples R China. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Sternwarte Gottingen, D-37083 Gottingen, Germany. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Manchester, Nuffield Radio Astron Lab, Jodrell Bank, Macclesfield SK11 9DL, Cheshire, England. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Chinese Acad Sci, Shanghai Astron Observ, Shanghai 20030, Peoples R China. LAEFF, E-28080 Madrid, Spain. Russian Acad Sci, Special Astrophys Observ, Nizhni Arkhyz 357147, Karachaj Cherkn, Russia. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Osservatorio Astron Bologna, I-40126 Bologna, Italy. Natl Cent Univ, Inst Astron, Chungli 32054, Taiwan. Chinese Acad Sci, Beijing Astron Observ, Beijing 100080, Peoples R China. RP O'Brien, PT (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. RI Morris, Simon/G-7981-2011; Recondo, Carmen/B-1215-2012; Stirpe, Giovanna/O-9393-2015; OI Morris, Simon/0000-0003-4866-110X; Recondo, Carmen/0000-0001-9813-6798; Stirpe, Giovanna/0000-0002-3702-8731; Gaskell, C/0000-0003-4888-2009 NR 57 TC 67 Z9 68 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP 163 EP 176 DI 10.1086/306464 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400016 ER PT J AU Jones, FC Jokipii, JR Baring, MG AF Jones, FC Jokipii, JR Baring, MG TI Charged-particle motion in electromagnetic fields having at least one ignorable spatial coordinate. SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; cosmic rays; methods : analytical; MHD ID SUPERCRITICAL COLLISIONLESS SHOCKS; WIND TERMINATION SHOCK; EARTHS BOW SHOCK; SOLAR-WIND; HYBRID SIMULATIONS; INTERPLANETARY SHOCKS; PERPENDICULAR SHOCKS; MAGNETIC-FIELDS; ACCELERATION; IONS AB We give a rigorous derivation of a theorem showing that charged particles in an arbitrary electromagnetic field with at least one ignorable spatial coordinate remain forever tied to a given magnetic field line. Such a situation contrasts with the significant motions normal to the magnetic field that are expected in most real three-dimensional systems. It is pointed out that while the significance of the theorem has not been widely appreciated, it has important consequences for a number of problems and is of particular relevance for the acceleration of cosmic rays by shocks. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Arizona, Tucson, AZ 85721 USA. RP Jones, FC (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 660, Greenbelt, MD 20771 USA. EM frank.c.jones@gsfc.nasa.gov; jokipii@lpl.arizona.edu; baring@lheavx.gsfc.nasa.gov NR 29 TC 81 Z9 82 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP 238 EP 243 DI 10.1086/306480 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400022 ER PT J AU Gezari, DY Backman, DE Werner, MW AF Gezari, DY Backman, DE Werner, MW TI Mid-infrared imaging of Orion BN/KL. II. Luminosity sources, extinction distribution, and the nature of IRc2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : ISM : continuum; ISM : individual (Orion-BN); ISM : individual (Orion Kleinmann-Low) ID APERTURE SYNTHESIS; MOLECULAR CLOUD; SIO MASER; STAR FORMATION; KLEINMANN-LOW; BN-KL; NEBULA; EMISSION; REGION; CORE AB We have recalculated the luminosities of IRc2 and the BN Object in the Orion BN/KL complex and determined the distributions of color temperature and silicate absorption-line strength over the region with much greater precision than before, using a complete set of well-sampled and nearly diffraction-limited array camera images of BN/KL at nine wavelengths between 4.8 and 20 mu m. We find that the total infrared luminosity of IRc2 itself is only L similar to 1000 L. (much lower than the generally accepted value). However, the temperature and extinction distributions show that the significant luminosity source(s) in BN/KL must still be located within several arcseconds of IRc2. Our results, considered with recent radio continuum and maser emission observations, suggest that a luminous early-type star located at radio source "I" is embedded close to IRc2, obscured by similar to 60 mag of visual extinction from dust grains both local to IRc2 and in intervening clouds along the line of sight. The combined heating contributions of the hot stars ionizing the compact H II regions "I" (near IRc2), "B" (the BN Object), and "L" (infrared source "n"), compact IRc objects (including 10 new peaks resolved here), and distributed near-infrared sources can account for the observed similar to 10(5) L. total luminosity of the BN/KL complex. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gezari, DY (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 48 TC 103 Z9 103 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP 283 EP 298 DI 10.1086/306462 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400027 ER PT J AU Wade, RA Hubeny, I AF Wade, RA Hubeny, I TI Detailed mid- and far-ultraviolet model spectra for accretion disks in cataclysmic binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; novae, cataclysmic variables; stars : atmospheres; ultraviolet : stars ID DWARF NOVAE; VARIABLES; STARS; ATMOSPHERES; TELESCOPE; EMISSION AB We present a large grid of computed far- and mid-ultraviolet spectra (850-2000 Angstrom) of the integrated light from steady-state accretion disks in luminous cataclysmic variables. The spectra are tabulated at 0.25 Angstrom intervals with an adopted FWHM resolution of 1.0 Angstrom, so they are suitable for use with observed spectra from a variety of modern space-borne observatories. Twenty-six different combinations of white dwarf mass M(wd) and mass accretion rate (m) over dot are considered, and spectra are presented for six different disk inclinations i. The disk models are computed self-consistently in the plane-parallel approximation, assuming LTE and vertical hydrostatic equilibrium, by solving simultaneously the radiative transfer, hydrostatic equilibrium, and energy balance equations. Irradiation from external sources is neglected. Local spectra of disk annuli are computed taking into account line transitions from elements 1-28 (H through Ni). Limb darkening as well as Doppler broadening and blending of lines are taken into account in computing the integrated disk spectra. The radiative properties of the models are discussed, including the dependence of ultraviolet fluxes and colors on M(wd), (m) over dot, and i. The appearance of the disk spectra is illustrated, with regard to changes in the same three parameters. Finally, possible future improvements to the present models and spectra are discussed. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, AURA, NOAO, Greenbelt, MD 20771 USA. RP Wade, RA (reprint author), Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. EM wade@astro.psu.edu; hubeny@tlusty.gsfc.nasa.gov NR 31 TC 91 Z9 91 U1 0 U2 0 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 DEC 10 PY 1998 VL 509 IS 1 BP 350 EP 361 DI 10.1086/306496 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400031 ER PT J AU Linnell, AP Hubeny, I Harmanec, P AF Linnell, AP Hubeny, I Harmanec, P TI New light synthesis and spectrum synthesis constraints on a model for beta Lyrae SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion : accretion disks; binaries : close; binaries : eclipsing; stars : individual (beta Lyrae) ID ACCRETION DISK; CATACLYSMIC VARIABLES; BINARY STARS; SYNTHESIS PROGRAM; ALGOL SYSTEMS; DWARF NOVAE; CURVES; ECLIPSES; EVAPORATION; TURBULENCE AB A suite of programs that calculates both synthetic light curves and synthetic spectra for a binary system with an optically thick accretion disk has been applied for the first time to beta Lyrae A. Our results demonstrate that the standard accretion disk model by Hubeny & Plavec shows significant residuals from observations, both photometric and spectroscopic, and that no changes in adjustable parameters are able to remove the residuals. The basic problem is that the Hubeny & Plavec model requires a small visible segment of the hot star at the center of the accretion disk and this requirement conflicts with the photometric evidence. As an alternative, we investigate standard accretion disk models in which the central star is hidden from view. We find that no model of this type can satisfy either the observed photometry or the IUE spectra. To resolve this impasse, we suggest the presence of a lightscattering region above the accretion disk faces, which scatters light from the central star into the line of sight and provides the high-T(eff) radiation component required by both the light curves and the observed spectra. This source of radiation is very likely related to the jets proposed by Harmanec et al. and Hoffman et al. We calculate the location of stream impact on the accretion disk rim. Observations show no detectable photometric signature of a rim bright spot. We suggest that the liberated kinetic energy is spread over a region sufficiently large and at a sufficient optical depth to suppress appearance of a bright spot. A slight asymmetry of primary minimum may indicate swelling of the accretion disk rim downstream from the stream impact point, with an attendant slight increase in obscuration of the background light sources. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NASA, Goddard Space Flight Ctr, NOAO, AURA, Greenbelt, MD 20771 USA. Acad Sci Czech Republic, Inst Astron, CS-25165 Ondrejov, Bohemia, Czech Republic. RP Linnell, AP (reprint author), Univ Washington, Dept Astron, Seattle, WA 98195 USA. EM linnell@pa.msu.edu; hubeny@stars.gsfc.nasa.gov; hec@sunstel.asu.cas.cz NR 81 TC 17 Z9 18 U1 0 U2 0 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 DEC 10 PY 1998 VL 509 IS 1 BP 379 EP 391 DI 10.1086/306484 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DE UT WOS:000079250400034 ER PT J AU Higdon, JC Lingenfelter, RE Ramaty, R AF Higdon, JC Lingenfelter, RE Ramaty, R TI Cosmic-ray acceleration from supernova ejecta in superbubbles SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; dust, extinction; Galaxy : abundances; Galaxy : evolution; supernovae : general ID OB ASSOCIATIONS; LUMINOSITY FUNCTION; SHOCK ACCELERATION; EVOLUTION; GALAXY; CLOUDS; DUST; GAS; REMNANTS; BUBBLES AB We suggest that the cosmic rays are accelerated primarily out of the supernova ejecta-enriched matter in the interiors of superbubbles. These hot, low-density superbubbles, which reach dimensions of several hundred parsecs, are generated by the winds and ejecta of supernova explosions of massive stars formed in giant molecular cloud OB associations that last for tens of megayears, Since these bubbles expand with shell velocities that are much faster than the dispersion velocities of the O and B star progenitors of the supernovae that power the bubbles, the bulk of the supernovae occur in their cores, The expanding remnants of each of these supernovae fill only less than 1% of this core before they have slowed to sonic velocities. Thus, the bulk of these supernovae remnants, together with their metal-rich grain and gas ejecta and their cosmic-ray-accelerating shocks, are well confined within the cores of superbubbles. These cores can thus provide a source of cosmic-ray matter of essentially constant metallicity throughout the age of the Galaxy, which is required to account for the constancy of cosmic-ray-produced Be relative to supernova-produced Fe observed in halo stars formed in the early Galaxy. The interactions of the grains and gas in metal-rich superbubbles, with recurrent supernova shocks every similar to 3 x 10(5) yr, also reconcile the requirement of a supernova ejects source of cosmic rays with the recent observations that require a greater than 10(5) yr delay between nucleosynthesis and acceleration for the cosmic-ray metals. Supernova-enriched bubble metallicity may also explain the X-ray emission from the interiors of superbubbles in the Large Magellanic Cloud. C1 Claremont Mckenna Coll, WM Keck Sci Ctr, Claremont, CA 91711 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Higdon, JC (reprint author), Claremont Mckenna Coll, WM Keck Sci Ctr, Claremont, CA 91711 USA. EM jimh@lobach.claremont.edu; rlingenfelter@ucsd.edu; ramaty@gsfc.nasa.gov NR 44 TC 96 Z9 96 U1 0 U2 0 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 DEC 10 PY 1998 VL 509 IS 1 BP L33 EP L36 DI 10.1086/311757 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DF UT WOS:000079250500009 ER PT J AU Koresko, CD van Belle, GT Boden, AF Colavita, MM Creech-Eakman, MJ Dumont, PJ Gubler, J Kulkarni, SR Lane, BF Mobley, DW Pan, XP Shao, M Wallace, JK AF Koresko, CD van Belle, GT Boden, AF Colavita, MM Creech-Eakman, MJ Dumont, PJ Gubler, J Kulkarni, SR Lane, BF Mobley, DW Pan, XP Shao, M Wallace, JK CA PTI Collaborat TI The visual orbit of the 0 '' 002 RS CVn binary star TZ Trianguli from near-infrared long-baseline interferometry SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : individual (TZ Trianguli); techniques : interferometric ID EMISSION; MASSES AB We report new observations of the RS Canum Venaticorum binary star TZ Trianguli with the Palomar Testbed Interferometer. The object exhibits fringe visibilities below the measured instrumental visibility, which indicates that it is partially resolved at the angular scales detectable by our observations. In most respects, the visibility data are consistent with the predictions of previous photometric and spectroscopic measurements. Comparison with a simple binary star model reveals clear evidence of orbital motion with the expected period and phase. The evolved primary star is resolved, and its size is found to be close to that derived by Hall in 1990. The relative brightness of the secondary star appears to be somewhat smaller than expected at the 2.2 mu m wavelength of the new observations. We conclude that the interferometric observations, which represent a new and nearly independent test of the models for this binary star, essentially confirm the spectroscopic results. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. RP Koresko, CD (reprint author), CALTECH, Div Geol & Planetary Sci, 1200 E Calif Blvd, Pasadena, CA 91125 USA. NR 9 TC 8 Z9 8 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP L45 EP L48 DI 10.1086/311759 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DF UT WOS:000079250500012 ER PT J AU Vassiliadis, D Anastasiadis, A Georgoulis, M Vlahos, L AF Vassiliadis, D Anastasiadis, A Georgoulis, M Vlahos, L TI Derivation of solar flare cellular automata models from a subset of the magnetohydrodynamic equations SO ASTROPHYSICAL JOURNAL LA English DT Article DE chaos; diffusion; MHD; Sun : flares; Sun : magnetic fields; turbulence ID DRIVEN DISSIPATIVE SYSTEMS; AVALANCHES; FREQUENCY AB Cellular automata (CA) models account for the power-law distributions found for solar flare hard X-ray observations, but their physics has been unclear. We examine four of these models and show that their criteria and magnetic field distribution rules can be derived by discretizing the MHD diffusion equation as obtained from a simplified Ohm's law. Identifying the discrete MHD with the CA models leads to an expression for the resistivity as a function of the current on the flux tube boundary, as may be expected from current-driven instabilities. Anisotropic CA models correspond to a nonlinear resistivity eta(J), while isotropic ones are associated with hyperresistivity eta(del(2)J). The discrete equations satisfy the necessary conditions for self-organized criticality (Lu): there is local conservation of a field (magnetic flux), while the nonlinear resistivity provides a rapid dissipation and relaxation mechanism. The approach justifies many features of the CA models that were originally based on intuition. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Univ Thessaloniki, Dept Phys, Sect Astrophys Astron & Mech, Thessaloniki 54006, Greece. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 692, Greenbelt, MD 20771 USA. RI Anastasiadis, Anastasios/G-8917-2011 NR 19 TC 37 Z9 37 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 1998 VL 509 IS 1 BP L53 EP L56 DI 10.1086/311750 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 178DF UT WOS:000079250500014 ER PT J AU Swanson, RC Radespiel, R Turkel, E AF Swanson, RC Radespiel, R Turkel, E TI On some numerical dissipation schemes SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE numerical dissipation; Euler; Navier-Stokes ID PRECONDITIONING METHODS; ARTIFICIAL DIFFUSION; CENTRAL-DIFFERENCE; GAS-DYNAMICS; EQUATIONS; DESIGN; FLOWS AB Several schemes for introducing an artificial dissipation into a central difference approximation to the Euler and Navier-Stokes equations are considered. The focus of the paper is on the convective upwind and split pressure (CUSP) scheme, which is designed to support single interior point discrete shock waves. This scheme is analyzed and compared in detail with scalar dissipation and matrix dissipation (MATD) schemes. Resolution capability is determined by solving subsonic, transonic, and hypersonic flow problems. A finite-volume discretization and a multistage time-stepping scheme with multigrid are used to compute solutions to the flow equations. Numerical solutions are also compared with either theoretical solutions or experimental data, For transonic airfoil flows the best accuracy on coarse meshes for aerodynamic coefficients is obtained with a simple MATD scheme. The coarse-grid accuracy for the original CUSP scheme is improved by modifying the limiter function used with the scheme, giving comparable accuracy to that obtained with the MATD scheme. The modifications reduce the background dissipation and provide control over the regions where the scheme can become first order. (C) 1998 Academic Press. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. DLR, Inst Design Aerodynam, Braunschweig, Germany. Tel Aviv Univ, Sackler Fac Exact Sci, Sch Math Sci, IL-69978 Tel Aviv, Israel. RP Swanson, RC (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. RI Turkel, Eli/F-6297-2011 OI Turkel, Eli/0000-0003-4273-0303 NR 35 TC 31 Z9 32 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC 10 PY 1998 VL 147 IS 2 BP 518 EP 544 DI 10.1006/jcph.1998.6100 PG 27 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 147YR UT WOS:000077525800013 ER PT J AU Myong, RS Roe, PL AF Myong, RS Roe, PL TI On Godunov-type schemes for magnetohydrodynamics 1. A model system SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Godunov-type schemes; conservation laws; magnetohydrodynamics ID DEGENERATE HYPERBOLIC SYSTEM; MHD INTERMEDIATE SHOCKS; CONSERVATION-LAWS; IDEAL MAGNETOHYDRODYNAMICS; RAREFACTION WAVES; RIEMANN PROBLEM; SOLAR-WIND; EQUATIONS; SOLVER; SPACE AB In the light of recent analytical results on the MHD Riemann problem, Godunov-type numerical schemes for magnetohydrodynamics (MHD) are revisited. As the first step, a model system that exactly preserves the MHD hyperbolic singularities is considered. For this model, analytical results on shock waves are summarized and critical problems occurring in developing shock-capturing methods are identified. Using the results, we propose a new way to define fluxes on cell interfaces. It consists of two solvers, one on the well-posed Riemann problem and another on the evolution of Alfven waves. Numerical experiments show that the new scheme is more efficient in calculating large-time solutions. (C) 1998 Academic Press. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Aerosp Engn, WM Keck Fdn Lab CFD, Ann Arbor, MI 48109 USA. RP Myong, RS (reprint author), NASA, Goddard Space Flight Ctr, Mail Stop 930, Greenbelt, MD 20771 USA. EM myong@lucullus.gsfc.nasa.gov; philroe@engin.umich.edu NR 45 TC 21 Z9 21 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC 10 PY 1998 VL 147 IS 2 BP 545 EP 567 DI 10.1006/jcph.1998.6101 PG 23 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 147YR UT WOS:000077525800014 ER PT J AU Peltzer, G Rosen, P Rogez, F Hudnut, K AF Peltzer, G Rosen, P Rogez, F Hudnut, K TI Poroelastic rebound along the Landers 1992 earthquake surface rupture SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID 28 JUNE 1992; DIFFERENTIAL RADAR INTERFEROMETRY; SYNTHETIC-APERTURE RADAR; SAN-ANDREAS FAULT; PORE FLUID-FLOW; MOJAVE-DESERT; SOUTHERN CALIFORNIA; EASTERN CALIFORNIA; TOPOGRAPHIC MAPS; HALF-SPACE AB Maps of surface displacement following the 1992 Landers, California, earthquake, generated by interferometric processing of ERS-1 synthetic aperture radar (SAR) images, reveal effects of various postseismic deformation processes along the 1992 surface rupture. The large-scale pattern of the postseismic displacement field includes large lobes, mostly visible on the west side of the fault, comparable in shape with the lobes observed in the coseismic displacement field. This pattern and the steep displacement gradient observed near the Emerson-Camp Rock fault cannot be simply explained by afterslip on deep sections of the 1992 rupture. Models show that horizontal slip occurring on a buried dislocation in a Poisson's material produces a characteristic quadripole pattern in the surface displacement field with several centimeters of vertical motion at distances of 10-20 km from the fault, yet this pattern is not observed in the postseismic interferograms. As previously proposed to explain local strain in the fault step overs [Peltzer er al., 1996b], we argue that poroelastic rebound caused by pore fluid flow may also occur over greater distances from the fault, compensating the vertical ground shift produced by fault afterslip. Such a rebound is explained by the gradual change of the crustal rocks' Poisson's ration value from undrained (coseismic) to drained (postseismic) conditions as pore pressure gradients produced by the earthquake dissipate. Using the Poisson's ratio values of 0.27 and 0.31 for the drained and undrained crustal rocks, respectively, elastic dislocation models show that the combined contributions of afterslip on deep sections of the fault and poroelastic rebound can account for the range change observed in the SAR data and the horizontal displacement measured at Global Positioning System (GPS) sites along a 60-km-long transect across the Emerson fault [Savage and Svarc, 1997]. Using a detailed surface slip distribution on the Homestead Valley, Kickapoo, and Johnson Valley faults, we modeled the poroelastic rebound in the Homestead Valley pull apart. A Poisson's ratio value: Of 0.35 for the undrained gouge rocks in the fault zone is required to for the observed surface uplift in the 3.5 years following the earthquake. This large value implies a seismic velocity ratio V-p/V-s of 2.1, consistent with the observed low V-s values of fault zone guided waves at shallow depth [Li et al., 1997]. The SAR data also reveal postseismic creep along shallow patches of the Eureka Peak and Burnt Mountain faults with a characteristic decay time of 0.8 years. Coseismic, dilatant hardening (locking process) followed by post-seismic, pore pressure controlled fault creep provide a plausible mechanism to account for the decay time of the observed slip rate along this section of the fault. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Pasadena, CA 91106 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-233, Pasadena, CA 91109 USA. EM gilles@altyn.jpl.nasa.gov RI Hudnut, Kenneth/B-1945-2009; Hudnut, Kenneth/G-5713-2010 OI Hudnut, Kenneth/0000-0002-3168-4797; NR 60 TC 164 Z9 171 U1 3 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 DEC 10 PY 1998 VL 103 IS B12 BP 30131 EP 30145 DI 10.1029/98JB02302 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 155VK UT WOS:000077966900023 ER PT J AU Bauschlicher, CW AF Bauschlicher, CW TI Heats of formation of GaCl3 and its fragments SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN-BASIS SETS; CORRELATED MOLECULAR CALCULATIONS; COUPLED-CLUSTER THEORY; ELECTRON CORRELATION; WAVE-FUNCTIONS; 3RD-ROW ATOMS; HARTREE-FOCK; ENERGIES; 1ST-ROW AB The heats of formation of GaCl3 and its fragments are computed. The geometries and frequencies are obtained at the B3LYP level. The CCSD(T) approach is used to solve the correlation problem. The effect of Ga 3d correlation is studied and found to affect the bond energies by up to 1 kcal/mol. Both basis set extrapolation and bond functions are considered as ways to approach the basis set limit. Spin-orbit and scalar relativistic effects are also considered. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, STC-230-3, Moffett Field, CA 94035 USA. NR 32 TC 19 Z9 19 U1 0 U2 1 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 DEC 10 PY 1998 VL 102 IS 50 BP 10424 EP 10429 DI 10.1021/jp9832600 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 148QP UT WOS:000077543700031 ER PT J AU Zioutas, K Thompson, DJ Paschos, EA AF Zioutas, K Thompson, DJ Paschos, EA TI Search for energetic cosmic axions utilizing terrestrial/celestial magnetic fields SO PHYSICS LETTERS B LA English DT Article DE energetic axion telescopes; (celestial) magnetic fields; Primakoff effect; gamma detectors ID ORTHOPOSITRONIUM DECAY; NEUTRON-STARS; GAMMA-RAYS; PSEUDOSCALAR CONVERSION; INVISIBLE-AXION; GALACTIC PLANE; SN 1987A; X-RAY; LIMITS; BOSONS AB Orbiting gamma-detectors combined with the external magnetic field of the Earth or the Sun can work parasitically as cosmic axion telescopes. The relatively short field lengths allow the axion-to-photon conversion to be coherent for m(axion) similar to 10(-4) eV, if the axion kinetic energy is above similar to 500 keV (Earth's field), or similar to 50 MeV (Sun's field), allowing thus searches for axions from e(+)c(-) annihilations, M1 transitions, supernova explosions, etc. With a detector angular resolution of similar to 1 degrees, a more efficient sky survey for energetic cosmic axions passing through the Sun can be performed. The axion signal will be an excess in gamma-rays coming either from an active celestial place behind the Sun, e.g. the Galactic Center, or, from any other direction in the sky being associated with a violent astrophysical event, e.g. a supernova. Earth bound detectors are also of potential interest. Similar to the axion searches in accelerator beam dump experiments, axions or other axion-like particles might be created during the interaction of the cosmic radiation with the Sun; the coherent axion-to-photon conversion inside Sun's external magnetic field is beyond the reach of man made magnets. The axion scenario also applies to other stars or binary systems in the Universe, in particular to those with superstrong magnetic/electric fields. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Thessaloniki, Dept Phys, GR-54006 Salonika, Greece. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Dortmund, Inst Phys, D-44221 Dortmund, Germany. RP Zioutas, K (reprint author), Univ Thessaloniki, Dept Phys, GR-54006 Salonika, Greece. RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 70 TC 5 Z9 5 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 DEC 10 PY 1998 VL 443 IS 1-4 BP 201 EP 208 DI 10.1016/S0370-2693(98)01346-X PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 152EP UT WOS:000077763500032 ER PT J AU Ahn, CC Ye, Y Ratnakumar, BV Witham, C Bowman, RC Fultz, B AF Ahn, CC Ye, Y Ratnakumar, BV Witham, C Bowman, RC Fultz, B TI Hydrogen desorption and adsorption measurements on graphite nanofibers SO APPLIED PHYSICS LETTERS LA English DT Article ID PRESSURE ADSORPTION; CARBON; STORAGE AB Graphite nanofibers were synthesized and their hydrogen desorption and adsorption properties are reported for 77 and 300 K. Catalysts were made by several different methods including chemical routes, mechanical alloying, and gas condensation. The nanofibers were grown by passing ethylene and H-2 gases over the catalysts at 600 degrees C. Hydrogen desorption and adsorption were measured using a volumetric analysis Sieverts' apparatus, and the graphite nanofibers were characterized by transmission electron microscopy and Brunauer-Emmett-Teller surface area analysis. The absolute level of hydrogen desorption measured from these materials was typically less than the 0.01 H/C atom, comparable to other forms of carbon. (C) 1998 American Institute of Physics. [S0003-6951(98)04549-5]. C1 CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ahn, CC (reprint author), CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. OI Bowman, Robert/0000-0002-2114-1713 NR 12 TC 208 Z9 212 U1 0 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 7 PY 1998 VL 73 IS 23 BP 3378 EP 3380 DI 10.1063/1.122755 PG 3 WC Physics, Applied SC Physics GA 146MJ UT WOS:000077432600020 ER PT J AU Nikzad, S Yu, QM Smith, AL Jones, TJ Tombrello, TA Elliott, ST AF Nikzad, S Yu, QM Smith, AL Jones, TJ Tombrello, TA Elliott, ST TI Direct detection and imaging of low-energy electrons with delta-doped charge-coupled devices SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; QUANTUM EFFICIENCY; LOSS SPECTROSCOPY; CCDS; ULTRAVIOLET; STABILITY; GROWTH; UV AB We report the use of delta-doped charge-coupled devices (CCDs) for direct detection of electrons in the 50-1500 eV energy range. We show that modification of the CCD back surface by molecular beam epitaxy can greatly improve sensitivity to low-energy electrons by introducing an atomically abrupt dopant profile to eliminate the dead layer. Using delta-doped CCDs, we have extended the energy threshold for detection of electrons by over an order of magnitude. We have also measured high gain in response to low-energy electrons using delta-doped CCDs. The effect of multiple electron hole pair production on the observed signals is discussed. Electrons have been directly imaged with a delta-doped CCD in the 250-750 eV range. (C) 1998 American Institute of Physics. [S0003-6951(98)03549-9]. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. RP Nikzad, S (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 18 TC 19 Z9 19 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 7 PY 1998 VL 73 IS 23 BP 3417 EP 3419 DI 10.1063/1.122783 PG 3 WC Physics, Applied SC Physics GA 146MJ UT WOS:000077432600033 ER PT J AU Lissauer, JJ AF Lissauer, JJ TI Looking for Earths - The race to find new solar systems SO SCIENCE LA English DT Book Review C1 NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, MS-245-3, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 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 DEC 4 PY 1998 VL 282 IS 5395 BP 1832 EP 1832 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 144WG UT WOS:000077338100029 ER PT J AU Dowling, JP AF Dowling, JP TI Optical physics - Mirror on the wall: You're omnidirectional after all? SO SCIENCE LA English DT Editorial Material C1 CALTECH, NASA, Jet Prop Lab, Quantum Comp Grp, Pasadena, CA 91109 USA. RP Dowling, JP (reprint author), CALTECH, NASA, Jet Prop Lab, Quantum Comp Grp, MS 126-347, Pasadena, CA 91109 USA. EM jonathan.p.dowling@jpl.nasa.gov RI DOWLING, JONATHAN/L-2749-2013 NR 4 TC 52 Z9 60 U1 0 U2 3 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 DEC 4 PY 1998 VL 282 IS 5395 BP 1841 EP 1842 DI 10.1126/science.282.5395.1841 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 144WG UT WOS:000077338100035 ER PT J AU Farassat, F Brentner, KS AF Farassat, F Brentner, KS TI Supersonic quadrupole noise theory for high-speed helicopter rotors SO JOURNAL OF SOUND AND VIBRATION LA English DT Article; Proceedings Paper CT American-Helicopter-Society-Technical-Specialists Meeting for Rotorcraft Acoustics and Aerodynamics CY OCT 28-30, 1997 CL WILLIAMSBURG, VIRGINIA SP Amer Helicopter Soc, Tech Specialists ID IMPULSIVE NOISE; ROBUST METHOD; PREDICTION; EFFICIENT AB High-speed helicopter rotor impulsive noise prediction is an important problem of aeroacoustics. The deterministic quadrupoles have been shown to contribute significantly to high-speed impulsive (HSI) noise of rotors, particularly when the phenomenon of delocalization occurs. At high rotor-tip speeds, some of the quadrupole sources lie outside the sonic circle and move at supersonic speed. Brentner has given a formulation suitable for efficient prediction of quadrupole noise inside the sonic circle. In this paper, a simple formulation is presented based on the acoustic analogy that is valid,for both subsonic and supersonic quadrupole noise prediction. Like the formulation of Brentner, the model is exact for an observer in the far field and in the rotor plane, and is approximate elsewhere. The full analytic derivation of this formulation is given in this paper. The method of implementation on a computer for supersonic quadrupoles using marching cubes for constructing the influence surface (C-surface) of an observer space-time variable (x, t) is presented. Then, several examples of noise prediction are given for both subsonic and supersonic quadrupoles. It is shown that in the case of transonic flow over rotor blades, the inclusion of the supersonic quadrupoles improves the prediction of the acoustic pressure signature. The equivalence is shown of the new formulation to that of Brentner for subsonic quadrupoles. It is shown that the regions of high quadrupole source strength are primarily produced by the shock surface and the flow over the leading edge of the rotor. The primary role of the supersonic quadrupoles is to increase the width of a strong acoustic signal. (C) 1998 Academic Press. C1 NASA, Fluid Mech & Acoust Div, Langley Res Ctr, Hampton, VA 23665 USA. RP Farassat, F (reprint author), NASA, Fluid Mech & Acoust Div, Langley Res Ctr, Hampton, VA 23665 USA. NR 27 TC 19 Z9 19 U1 1 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD DEC 3 PY 1998 VL 218 IS 3 BP 481 EP 500 DI 10.1006/jsvi.1998.1836 PG 20 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 142WH UT WOS:000077223000007 ER PT J AU Bills, BG AF Bills, BG TI An oblique view of climate SO NATURE LA English DT Editorial Material ID EARTHS OBLIQUITY; GLACIATION; FRICTION C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, Scripps Inst Oceanog,Inst Geophys & Planetary Phy, Greenbelt, MD 20771 USA. RP Bills, BG (reprint author), NASA, Goddard Space Flight Ctr, Geodynam Branch, Scripps Inst Oceanog,Inst Geophys & Planetary Phy, Mailstop 921-0, Greenbelt, MD 20771 USA. RI Bills, Bruce/C-1156-2008 NR 12 TC 4 Z9 5 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD DEC 3 PY 1998 VL 396 IS 6710 BP 405 EP 406 DI 10.1038/24711 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 145KL UT WOS:000077370100020 PM 9853740 ER PT J AU Sistla, AP Wolfson, O AF Sistla, AP Wolfson, O TI Towards a theory of cost management for digital libraries and electronic commerce SO ACM TRANSACTIONS ON DATABASE SYSTEMS LA English DT Article DE average case analysis; caching; cost models; demand; on-line services; protocols; subscription; worst case analysis AB One of the features that distinguishes digital libraries from traditional databases is new cost models for client access to intellectual property. Clients will pay for accessing data items in digital libraries, and we believe that optimizing these costs will be as important as optimizing performance in traditional databases. In this article we discuss cost models and protocols for accessing digital libraries, with the objective of determining the minimum cost protocol for each model. We expect that in the future information appliances will come equipped with a cost optimizer, in the same way that computers today come with a built-in operating system. This article makes the initial steps towards a theory and practice of intellectual property cost management. C1 Univ Illinois, Dept Elect Engn & Comp Sci, Chicago, IL 60607 USA. NASA, Goddard Space Flight Ctr, Ctr Excellence Space Data & Informat Sci, Greenbelt, MD 20771 USA. RP Sistla, AP (reprint author), Univ Illinois, Dept Elect Engn & Comp Sci, 851 S Morgan St, Chicago, IL 60607 USA. EM wolfson@eecs.uic.edu NR 29 TC 3 Z9 3 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0362-5915 EI 1557-4644 J9 ACM T DATABASE SYST JI ACM Trans. Database Syst. PD DEC PY 1998 VL 23 IS 4 BP 411 EP 452 DI 10.1145/296854.277641 PG 42 WC Computer Science, Information Systems; Computer Science, Software Engineering SC Computer Science GA 180CK UT WOS:000079367400002 ER PT J AU Giering, R Kaminski, T AF Giering, R Kaminski, T TI Recipes for adjoint code construction SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE adjoint model; adjoint operator; automatic differentiation; computational differentiation; data assimilation; differentiation of algorithms; implicit functions; inverse modeling; optimization; reverse mode ID GENERAL-CIRCULATION MODEL; EQUATORIAL OCEAN MODEL; DATA ASSIMILATION; PARAMETERIZED DISCONTINUITIES; METEOROLOGICAL OBSERVATIONS; VARIATIONAL ASSIMILATION; VORTICITY EQUATION; PHYSICAL PROCESSES AB Adjoint models are increasingly being developed for use in meteorology and oceanography. Typical applications are data assimilation, model tuning, sensitivity analysis, and determination of singular vectors. The adjoint model computes the gradient of a cost function with respect to control variables. Generation of adjoint code may be seen as the special case of differentiation of algorithms in reverse mode, where the dependent function is a scalar. The described method for adjoint code generation is based on a few basic principles, which permits the establishment of simple construction rules for adjoint statements and complete adjoint subprograms. These rules are presented and illustrated with some examples. Conflicts that occur due to loops and redefinition of variables are also discussed. Direct coding of the adjoint of a more sophisticated model is extremely time consuming and subject to errors. Hence, automatic generation of adjoint code represents a distinct advantage. An implementation of the method, described in this article, is the tangent linear and adjoint model compiler (TAMC). C1 Max Planck Inst Meteorol, D-20146 Hamburg, Germany. RP Giering, R (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ralf@oceanaut.jpl.nasa.gov NR 36 TC 393 Z9 403 U1 0 U2 18 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD DEC PY 1998 VL 24 IS 4 BP 437 EP 474 DI 10.1145/293686.293695 PG 38 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 173KC UT WOS:000078978900007 ER PT J AU Fay, CC Hinkley, JA St Clair, TL Working, C AF Fay, CC Hinkley, JA St Clair, TL Working, C TI Mechanical properties of LaRC (TM)-IA and ULTEM (R) melt-extruded fibers and melt-pressed films SO ADVANCED PERFORMANCE MATERIALS LA English DT Article DE melt extrusion; polyimide fibers; tensile properties; LaRC (TM)-IA; ULTEM (R) ID POLYIMIDE AB LaRC(TM)-IA, the polyimide prepared with 3,4'-oxydianiline (3,4'-ODA) and oxydiphthalic anhydride (ODPA), is useful as a film, coating, adhesive, and composite matrix. The high temperature capability and fire-resistance of polyimides also makes them attractive candidates for textile fibers for a variety of uses in the automotive, chemical, and aerospace industries. This research describes for the first time the melt-spinning of phthalic anhydride endcapped LaRC(TM)-IA and the effects of processing conditions on the mechanical properties of slightly-drawn fibers. Average draw ratios varied from 1 to 3.9. Tensile strengths ranged from 103 to 159 MPa; moduli ranged from 2.80 to 3.21 GPa; elongations at break ranged from 14 to 103%. For comparison, tensile properties of compression-molded films prepared at the same temperatures are also reported. Melt-extruded fibers and melt-pressed films of another thermoplastic, ULTEM(R), were also fabricated. ULTEM(R) fibers exhibited tensile strengths ranging from 138 to 207 MPa for average draw ratios of 4.5 to 10.3. Moduli ranged from 2.70 to 3.22 GPa. Elongations at break ranged from 47 to 111%. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Mitsubishi Chem Amer, Chesapeake, VA 23320 USA. NR 22 TC 2 Z9 3 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0929-1881 J9 ADV PERFORM MATER JI Adv. Perform. Mater. PD DEC PY 1998 VL 5 IS 3 BP 193 EP 200 DI 10.1023/A:1008630431071 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 155HX UT WOS:000077941900004 ER PT J AU Fenno, CC Bayliss, A Maestrello, L AF Fenno, CC Bayliss, A Maestrello, L TI Interaction of sound from supersonic jets with nearby structures SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 35th Aerospace Science Meeting / Nonlinear Dynamical Systems Symposium CY JAN 06-10, 1997 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut, USAF, Off Sci Res, Sandia Natl Labs ID NOISE; VIBRATION; RADIATION; LAYER; FLOW AB We numerically solve a model of sound generated in an ideally expanded two-dimensional supersonic (Mach 2) jet. Two configurations are considered: 1) a free jet and 2) an installed jet with a nearby array of flexible aircraft type panels, In the later case the panels vibrate in response to loading by sound from the jet, and the full coupling between the panels and the jet is simulated, accounting for panel response and radiation as well as the jet acoustics, We consider the Long time behavior of the jet/panel system and present results for the flowfield and far field pressure and the vibration of, and radiation from, the panels. The pressure within the jet changes from a nearly discrete spectrum peaked at a preferred frequency f*, which depends on properties of the jet, to a continuous spectrum as downstream distance increases. The far-field pressure is characterized by a highly directional beaming of sound with a spectral peak atf, within the Mach line and a lower-level breakup into small-scale structures away from the Mach line, We show that the location of the panels relative to the Mach line is critical in determining panel response, Panels located upstream of the Mach line are subject to a low-level continuous spectrum loading and exhibit a comparable response. In contrast, panels located within the Mach line are subject to a high-lever loading due to the intense Mach wave radiation of sound peaked atf, and exhibit a comparable response. The panels radiate in a similar fashion to the sound in the jet, In particular, there is a strong beaming of sound waves at frequency f* from the excited panels within the Mach angle from the bounding wall, indicating a significant effect of Mach wave radiation on both interior sound levels and spectral content in the supersonic regime. C1 NASA, Langley Res Ctr, Fluid Mech & Acoust Div, MS 263, Hampton, VA 23681 USA. Northwestern Univ, Dept Engn Sci & Appl Math, Evanston, IL 60208 USA. RP Fenno, CC (reprint author), InterNational Res Inst, Newport News, VA 23602 USA. RI Bayliss, Alvin/B-7337-2009 NR 25 TC 4 Z9 4 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1998 VL 36 IS 12 BP 2153 EP 2162 DI 10.2514/2.329 PG 10 WC Engineering, Aerospace SC Engineering GA 148KK UT WOS:000077503900001 ER PT J AU Bhardwaj, MK Kapania, RK Reichenbach, E Guruswamy, GP AF Bhardwaj, MK Kapania, RK Reichenbach, E Guruswamy, GP TI Computational fluid dynamics computational structural dynamics interaction methodology for aircraft wings SO AIAA JOURNAL LA English DT Article ID EQUATIONS AB With advanced subsonic transports and military aircraft operating in the transonic regime, it is becoming important to determine the effects of the coupling between aerodynamic loads and elastic forces. Because aeroelastic effects can significantly impact the design of these aircraft, there is a strong need in the aerospace industry to predict these interactions computationally. Such an analysis in the transonic regime requires high-fidelity computational fluid dynamics (CFD) analysis tools, due to the nonlinear behavior of the aerodynamics, and high-fidelity computational structural dynamics (CSD) analysis tools. Also, there is a need to be able to use a wide variety of CFD and CSD methods to predict aeroelastic effects. Because source codes are not always available, it is necessary to couple the CFD and CSD codes without alteration of the source codes. In this study, an aeroelastic coupling procedure is developed to determine the static aeroelastic response of aircraft wings using any CFD and CSD code with little code integration. The procedure is demonstrated on an F/A-18 stabilator using NASTD tan in-house McDonnell Douglas CFD code) and NASTRAN. In addition, the Aeroelastic Research Wing is used for demonstration with ENSAERO (NASA Ames Research Center CFD code) coupled with a finite element wing-box code. The results obtained from the present study are compared with those available from an experimental study conducted at NASA Langley Research Center and a study conducted at NASA Ames Research Center using ENSAERO and modal superposition. The results compare well with experimental data. C1 Virginia Polytech Inst & State Univ, Dept Aerosp & Ocean Engn, Blacksburg, VA 24061 USA. Boeing Co, Aeromech Dept, St Louis, MO 63166 USA. NASA, Ames Res Ctr, Appl Computat Aerodynam Branch, Moffett Field, CA 94035 USA. RP Bhardwaj, MK (reprint author), Sandia Natl Labs, Struct Dynam Dept, Limited Term Staff, POB 5800,MS-0439, Albuquerque, NM 87185 USA. NR 43 TC 20 Z9 20 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1998 VL 36 IS 12 BP 2179 EP 2186 DI 10.2514/2.342 PG 8 WC Engineering, Aerospace SC Engineering GA 148KK UT WOS:000077503900004 ER PT J AU Venter, G Haftka, RT Starnes, JH AF Venter, G Haftka, RT Starnes, JH TI Construction of response surface approximations for design optimization SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/USAF/NASA/ISSMO 6th Symposium on Multidisciplinary Analysis and Optimization CY SEP 04-06, 1996 CL BELLEVUE, WASHINGTON SP AIAA, USAF, NASA, ISSMO AB Using response surface approximations for design constraints in design optimization provides the designer with an overall perspective of the system response within the design space. Response surface approximations also reduce the numerical noise inherent in many numerical models and simplify the process of integrating several design codes, as is typically required in multidisciplinary optimization. Procedures are discussed for constructing accurate response surface approximations to represent design constraints in design optimization. Response surface approximations are constructed for the stresses and buckling loads of an isotropic plate with an abrupt change of thickness. These response surface approximations are constructed from numerical experiments conducted with a finite element analysis procedure and are used for minimum-weight optimum design of the plate. Nondimensional variables and stepwise regression are used to reduce the complexity and increase the accuracy of the response surface approximations. Additionally, higher-order polynomials (cubic and quartic instead of the more traditional quadratic) are used as response surface approximations, and a detailed error analysis, using an independent data set, is performed. Finally, it is shown that, by making use of response surface approximations, the optimum weight of the plate may be presented in the form of a design chart for a wide range of geometric, loading, and material constants. C1 Univ Florida, Dept Aerosp Engn Mech & Engn Sci, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23681 USA. RP Venter, G (reprint author), Vanderplaats Res & Dev Inc, Res & Dev, 1767 S 8th St,Suite 210, Colorado Springs, CO 80906 USA. OI Venter, Gerhard/0000-0001-9513-9774 NR 17 TC 40 Z9 40 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1998 VL 36 IS 12 BP 2242 EP 2249 DI 10.2514/2.333 PG 8 WC Engineering, Aerospace SC Engineering GA 148KK UT WOS:000077503900013 ER PT J AU Ashen, JB Goff, LJ AF Ashen, JB Goff, LJ TI Galls on the marine red alga Prionitis lanceolata (Halymeniaceae): Specific induction and subsequent development of an algal-bacterial symbiosis SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE eubacteria; galls; Halymeniaceae; in situ hybridization; Prionitis lanceolata; red algae; symbiosis ID WHOLE-CELL HYBRIDIZATION; SEQUENCE-ANALYSIS; IDENTIFICATION; INSITU; ENDOSYMBIONTS; CHLOROPHYCEAE; LOCALIZATION AB Gall formation in Prionitis laceolata is associated with a specific eubacterium (Proteobacteria [alpha subclass], Rhodobacter grouping), which, typical of bacterial symbionts, has not yet been cultivated or isolated in pure culture. This investigation tested the hypothesis that P. laceolata gall formation was caused by the associated eubacterium using a species-specific rDNA probe (S-S-P.l.sym-0949-a-A-25) to identify and assay for symbiont presence during consecutive laboratory induction trials. Gall induction was quantified and whole-cell in situ hybridization used to determine the relative percentage of symbiotic eubacteria in inoculation homogenates. In situ hybridization of symbionts in sections allowed localization and monitoring of this microbe during gall development. Induction trial results indicate a significant correlation between bacterial symbiont presence and gall initiation (P = 0.00005). The gall bacterium comprised the majority of the eubacteria hybridized in laboratory induction homogenates (85-97%?), in galls induced in the laboratory and in three algal populations in nature. The evidence presented here demonstrates the causative role of the identified eubacterium in gall induction and formation. This investigation is significant in the application of molecular methods towards understanding the roles of noncultivable marine bacteria in marine algal-microbe interactions. C1 Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. RP Ashen, JB (reprint author), NASA, Ames Res Ctr, Mail Stop 239-12, Moffett Field, CA 94035 USA. NR 30 TC 16 Z9 16 U1 0 U2 10 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY 1735 NEIL AVE, COLUMBUS, OH 43210 USA SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD DEC PY 1998 VL 85 IS 12 BP 1710 EP 1721 DI 10.2307/2446505 PG 12 WC Plant Sciences SC Plant Sciences GA 151BX UT WOS:000077696200007 PM 21719414 ER PT J AU Thrasher, TN Keil, LC AF Thrasher, TN Keil, LC TI Arterial baroreceptors control blood pressure and vasopressin responses to hemorrhage in conscious dogs SO AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY LA English DT Article DE angiotensin; antidiuretic hormone; adrenocorticotropic hormone; cardiac receptors; atrial receptors; blood volume ID CARDIAC NERVE BLOCKADE; PLASMA VASOPRESSIN; ATRIAL PRESSURE; RELATIVE ROLES; RENIN RELEASE; SECRETION; RECEPTORS; MECHANISMS; CORTISOL; PROCAINE AB The goal of this study was to determine the role of arterial baroreceptors in the reflex control of arginine vasopressin (AVP), renin, and cortisol secretion in response to a 30-ml/kg hemorrhage in conscious dogs. The hormonal responses were measured in six dogs under four treatment conditions: 1) intact, 2) acute cardiac denervation (CD) by intrapericardial infusion of procaine, 3) after sinoaortic denervation (SAD), and 4) during combined SAD + CD. In the intact condition, mean arterial pressure (MAP) was maintained at control levels until blood loss reached 20 ml/kg and the absolute magnitude of the fall at 30 ml/kg was 35 +/- 10 mmHg. Similar responses were obtained during acute CD. In contrast, MAP fell earlier (at 5 ml/kg, P < 0.05) and to much lower levels in both the SAD and SAD + CD conditions. The individual slopes relating systolic pressure to plasma AVP, renin activity (PRA), and cortisol were used to compare the treatment effects using a 2 X 2 factorial analysis. There was a significant (P < 0.01) effect of SAD on the slope relating AVP to systolic pressure but no effect of CD and no SAD X CD interaction. In contrast, there was no effect of either SAD or CD on the relationship between PRA or plasma cortisol and systolic pressure. These results indicate that maintenance of blood pressure and the normal pattern of ANP secretion during hemorrhage depend on intact arterial baroreceptor reflexes. C1 Univ Maryland, Dept Surg, Baltimore, MD 21201 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Thrasher, TN (reprint author), Univ Maryland, Dept Surg, 10 S Pine St,Rm 400, Baltimore, MD 21201 USA. FU NHLBI NIH HHS [HL-41313] NR 41 TC 20 Z9 20 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6119 J9 AM J PHYSIOL-REG I JI Am. J. Physiol.-Regul. Integr. Comp. Physiol. PD DEC PY 1998 VL 275 IS 6 BP R1843 EP R1857 PG 15 WC Physiology SC Physiology GA 155YA UT WOS:000077973200013 PM 9843873 ER PT J AU Beyerle, G McDermid, IS AF Beyerle, G McDermid, IS TI Ray-tracing formulas for refraction and internal reflection in uniaxial crystals SO APPLIED OPTICS LA English DT Article ID MONOAXIAL OPTICAL-COMPONENTS; ACTIVE MEDIA AB Formulas for the calculation of the direction cosines of refracted and internally reflected rays in anisotropic uniaxial crystals are presented. The method is based on a transformation to a nonorthonormal coordinate system in which the normal surface associated with the extraordinary ray is of spherical shape. A numerical example for the case of refraction and internal reflection in calcite is given. (C) 1998 Optical Society of America. C1 CALTECH, Jet Prop Lab, Table Mt Facil, Wrightwood, CA 92397 USA. RP Telegraphenberg A43, D-14473 Potsdam, Germany. EM mcdermid@tmf.jpl.nasa.gov OI Beyerle, Georg/0000-0003-1215-2418 NR 10 TC 21 Z9 23 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 DEC 1 PY 1998 VL 37 IS 34 BP 7947 EP 7953 DI 10.1364/AO.37.007947 PG 7 WC Optics SC Optics GA 141XB UT WOS:000077168600003 PM 18301683 ER PT J AU Keski-Kuha, RAM Blumenstock, GM Fleetwood, CM Schmitt, DR AF Keski-Kuha, RAM Blumenstock, GM Fleetwood, CM Schmitt, DR TI Effects of space exposure on ion-beam-deposited silicon-carbide and boron-carbide coatings SO APPLIED OPTICS LA English DT Article ID EXTREME-ULTRAVIOLET; REFLECTANCE; DEGRADATION; FILMS; ORBIT AB Two recently developed optical coatings, ion-beam-deposited silicon carbide and ion-beam-deposited boron carbide, are very attractive as coatings on optical components for instruments for space astronomy and earth sciences operating in the extreme-UV spectral region because of their high reflectivity, significantly higher than any conventional coating below 105 nm. To take full advantage of these coatings in space applications, it is important to establish their ability to withstand exposure to the residual atomic oxygen and other environmental effects at low-earth-orbit altitudes. The first two flights of the Surface Effects Sample Monitor experiments flown on the ORFEUS-SPAS and the CRISTA-SPAS Shuttle missions provided the opportunity to study the effects of space exposure on these materials. The results indicate a need to protect ion-beam-deposited silicon-carbide-coated optical components from environmental effects in a low-earth orbit. The boron-carbide thin-film coating is a more robust coating able to withstand short-term exposure to atomic oxygen in a low-earth-orbit environment. (C) 1998 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Deutsch Zentrum Luft & Raumfahrt, Inst Flugfuhrung, D-38108 Braunschweig, Germany. RP Keski-Kuha, RAM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 9 Z9 10 U1 4 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 1998 VL 37 IS 34 BP 8038 EP 8042 DI 10.1364/AO.37.008038 PG 5 WC Optics SC Optics GA 141XB UT WOS:000077168600016 PM 18301696 ER PT J AU Sahoo, NK Shapiro, AP AF Sahoo, NK Shapiro, AP TI MgO-Al2O3-ZrO2 amorphous ternary composite: a dense and stable optical coating SO APPLIED OPTICS LA English DT Article ID PARTIALLY STABILIZED ZIRCONIA; ION-ASSISTED DEPOSITION; THIN-FILMS; OXIDE-FILMS; SPUTTER-DEPOSITION; BEAM; MICROSTRUCTURE; COEVAPORATION; CONSTANTS; ZRO2 AB The process-parameter-dependent optical and structural properties of MgO-Al2O3-ZrO2 ternary mixed composite material were investigated. Optical properties were derived from spectrophotometric measurements. The surface morphology, grain size distributions, crystallographic phases, and process-dependent material composition of films were investigated through the use of atomic force microscopy, x-ray diffraction analysis, and energy-dispersive x-ray analysis. Energy-dispersive x-ray analysis made evident the correlation between the optical constants and the process-dependent compositions in the films. It is possible to achieve environmentally stable amorphous films with high packing density under certain optimized process conditions. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Bhabha Atom Res Ctr, Div Spect, Bombay 400085, Mumbai, India. RP Sahoo, NK (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Code EB52, Huntsville, AL 35812 USA. NR 32 TC 11 Z9 13 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 1998 VL 37 IS 34 BP 8043 EP 8056 DI 10.1364/AO.37.008043 PG 14 WC Optics SC Optics GA 141XB UT WOS:000077168600017 PM 18301697 ER PT J AU Yamashita, K Serlemitsos, PJ Tueller, J Barthelmy, SD Bartlett, LM Chan, KW Furuzawa, A Gehrels, N Haga, K Kunieda, H Kurczynski, P Lodha, G Nakajo, N Nakamura, N Namba, Y Ogasaka, Y Okajima, T Palmer, D Parsons, A Soong, Y Stahl, SM Takata, H Tamura, K Tawara, Y Teegarden, BJ AF Yamashita, K Serlemitsos, PJ Tueller, J Barthelmy, SD Bartlett, LM Chan, KW Furuzawa, A Gehrels, N Haga, K Kunieda, H Kurczynski, P Lodha, G Nakajo, N Nakamura, N Namba, Y Ogasaka, Y Okajima, T Palmer, D Parsons, A Soong, Y Stahl, SM Takata, H Tamura, K Tawara, Y Teegarden, BJ TI Supermirror hard-x-ray telescope SO APPLIED OPTICS LA English DT Article ID MULTILAYER SUPERMIRROR; MIRRORS AB The practical use of a grazing x-ray telescope is demonstrated for hard-x-ray imaging as hard as 40 keV by means of a depth-graded d-spacing multilayer, a so-called supermirror. Platinum-carbon multilayers of 26 layer pairs in three blocks with a different periodic length d of 3-5 nm were designed to enhance the reflectivity in the energy range from 24 to 36 keV at a grazing angle of 0.3 deg. The multilayers were deposited on thin-replica-foil mirrors by a magnetron de sputtering system. The reflectivity was measured to be 25%-30% in this energy range; 20 mirror shells thus deposited were assembled into the tightly nested grazing-incidence telescope. The focused hard-x-ray image was observed with a newly developed position-sensitive CdZnTe solid-state detector. The angular resolution of this telescope was found to be 2.4 arc min in the half-power diameter. (C) 1998 Optical Society of America. C1 Nagoya Univ, Dept Phys, Chikusa Ku, Nagoya, Aichi 4648602, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Chubu Univ, Dept Mech Engn, Kasugai, Aichi 487, Japan. RP Yamashita, K (reprint author), Nagoya Univ, Dept Phys, Chikusa Ku, Nagoya, Aichi 4648602, Japan. RI Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; Barthelmy, Scott/D-2943-2012; Parsons, Ann/I-6604-2012 NR 16 TC 98 Z9 100 U1 2 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 1998 VL 37 IS 34 BP 8067 EP 8073 DI 10.1364/AO.37.008067 PG 7 WC Optics SC Optics GA 141XB UT WOS:000077168600019 PM 18301699 ER PT J AU Volin, CE Ford, BK Descour, MR Garcia, JP Wilson, DW Maker, PD Bearman, GH AF Volin, CE Ford, BK Descour, MR Garcia, JP Wilson, DW Maker, PD Bearman, GH TI High-speed spectral imager for imaging transient fluorescence phenomena SO APPLIED OPTICS LA English DT Article ID SPECTROMETER AB We describe fluorescence spectral imaging results with the microscope computad-tomography imaging spectrometer (mu CTIS). This imaging spectrometer is capable of recording spatial and spectral data simultaneously. Consequently, mu CTIS can be used to image dynamic phenomena. The results presented consist of proof-of-concept imaging results with static targets composed of 6-mu m fluorescing microspheres. Image data were collected with integration times of 18 ms, comparable with video-frame-rate integration times. Conversion of raw data acquired by the mu CTIS to spatial and spectral data requires postprocessing. The emission spectra were sampled at 10-nm intervals between 420 and 710 nm. The smallest spatial sampling interval presented is 1.7 mu m. (C) 1998 Optical Society of America. C1 Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Volin, CE (reprint author), Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. NR 15 TC 12 Z9 12 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 1998 VL 37 IS 34 BP 8112 EP 8119 DI 10.1364/AO.37.008112 PG 8 WC Optics SC Optics GA 141XB UT WOS:000077168600025 PM 18301705 ER PT J AU Wickramasekera, IE Kolm, P Pope, A Turner, M AF Wickramasekera, IE Kolm, P Pope, A Turner, M TI Observation of a paradoxical temperature increase during cognitive stress in some chronic pain patients SO APPLIED PSYCHOPHYSIOLOGY AND BIOFEEDBACK LA English DT Article DE stress; paradoxical vasodilatation; hand temperature AB A total of 224 chronic pain somatoform disorder patients without obvious pathophysiology or psychopathology were found to have colder hands than nonpatients. A paradoxical temperature increase (PTI) in response to a cognitive stressor (mental arithmetic) was noted in a subset of these chronic pain patients. Patients were defined as "PTI" responders if during cognitive stress, an increase in digital temperature occurred over a prior eyes closed resting condition. It was found that 49.4% of males and 42.6% of females in a total sample of 224 patients demonstrated PTI. The PTI patients had significantly colder hands than non-PTI patients prior to stress. A concurrent SCL measure of sympathetic activation found no difference between the PTI and non-PTI groups either at baseline or during cognitive stress. It appears from this data that PTI is specific to the peripheral vascular system of these patients and may be a marker of psychophysiological dissociation or trauma blocked from consciousness. C1 Saybrook Inst, Stanford, CA 94305 USA. Stanford Med Sch, Stanford, CA USA. Eastern Virginia Med Sch, Norfolk, VA 23501 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Wickramasekera, IE (reprint author), Saybrook Inst, Stanford, CA 94305 USA. NR 34 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1090-0586 J9 APPL PSYCHOPHYS BIOF JI Appl. Psychophysiol. Biofeedback PD DEC PY 1998 VL 23 IS 4 BP 233 EP 241 DI 10.1023/A:1022261615117 PG 9 WC Psychology, Clinical SC Psychology GA 218MT UT WOS:000081556900004 PM 10457814 ER PT J AU Tziotziou, K Martens, PCH Hearn, AG AF Tziotziou, K Martens, PCH Hearn, AG TI Energy and momentum deposition in coronal holes - Solar coronal hole simulations compared with interpretations of Yohkoh SXT observations SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE hydrodynamics; methods : numerical; stars : coronae; stars : mass loss ID STELLAR CORONAE; TEMPERATURE STRUCTURE; TRANSITION REGION; MAGNETIC-FIELD; ALFVEN WAVES; WIND PLASMA; A MISSION; BALANCE; ATMOSPHERE; MODELS AB A grid of 74 coronal models with parameterized heating distribution, representing a wide range of physical parameters, has been calculated. We find that three of these models reproduce the recent observations made by Hara et al. (1994) with the soft X-ray telescope aboard the Japanese satellite Yohkoh, which indicate a temperature of 1.8 similar to 2.4 x 10(6) K with an emission measure of 10(25.5) to 10(26.2) cm(-5), while other solutions reproduce the more standard Yohkoh and Skylab observations, which have a temperature of about 1.4 x 10(6) K. The best fit for the coronal temperature and emission measure gives a velocity at the Earth's orbit of only 10 km s(-1). A model including acceleration by Alfven waves gives a final velocity of 630 km s(-1) which is in agreement with the observations. The mechanical heating flux at the transition region is 2.1 x 10(5) erg cm(-2) s(-1) with a weighted average dissipation scale length of 0.1 R.. The flux of Alfven waves is 2.1 x 10(5) erg cm(-2) s(-1). In our models the velocity of the solar wind from coronal holes is completely determined by the Alfven wave acceleration, in contrast to previous models in which the Alfven wave acceleration increased the velocity of the purely thermal model only by a factor 2. Observations of the non thermal broadening of the coronal red and green lines are consistent with this model. C1 Sterrekundig Inst, NL-3508 TA Utrecht, Netherlands. NASA, Goddard Space Flight Ctr, ESA Space Sci Dept, SOHO Project, Greenbelt, MD 20771 USA. RP Hearn, AG (reprint author), Sterrekundig Inst, POB 80000, NL-3508 TA Utrecht, Netherlands. EM A.G.Hearn@astro.uu.nl RI Tziotziou, Konstantinos/L-5415-2013 NR 53 TC 4 Z9 4 U1 0 U2 1 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 DEC PY 1998 VL 340 IS 1 BP 203 EP 215 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 144FK UT WOS:000077303200025 ER PT J AU Stetson, PB Saha, A Ferrarese, L Rawson, DM Ford, HC Freedman, WL Gibson, BK Graham, JA Harding, P Han, MS Hill, RJ Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Kelson, DD Kennicutt, RC Madore, BF Mould, JR Phelps, RL Sakai, S Silberman, NA Turner, A AF Stetson, PB Saha, A Ferrarese, L Rawson, DM Ford, HC Freedman, WL Gibson, BK Graham, JA Harding, P Han, MS Hill, RJ Hoessel, JG Huchra, JP Hughes, SMG Illingworth, GD Kelson, DD Kennicutt, RC Madore, BF Mould, JR Phelps, RL Sakai, S Silberman, NA Turner, A TI The extragalactic distance scale key project. XVI. Cepheid variables in an inner field of M101 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; galaxies : distances and redshifts; galaxies : individual (M101); galaxies : photometry ID HUBBLE-SPACE-TELESCOPE; H-II REGIONS; STELLAR PHOTOMETRY; PEAK BRIGHTNESS; CCD PHOTOMETRY; CALIBRATION; DISCOVERY; PROGRAM; WFPC2; HST AB We report on the identification of 255 candidate variable stars in a field located some 1.'7 from the center of the late-type spiral galaxy M101 = NGC 5457, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Photometric measurements in the F555W and F814W filters-analyzed independently with the DAOPHOT/ALLFRAME and DoPHOT software suites-have been transformed to the Johnson V and Kron-Cousins I standard magnitude systems. Periods and intensity-averaged mean magnitudes for 61 carefully selected candidate Cepheid variables with periods in the range 10-48 days indicate a reddening-corrected mean distance modulus (m - M)(o) = 29.05 +/- 0.14 (if the true modulus of the Large Magellanic Cloud is 18.50 +/- 0.10, and if there is no dependence of the period-luminosity relation on metal abundance); results consistent with this are obtained whether or not the sample is expanded to include a larger fraction of the candidates. Applying a metallicity-dependent correction of +0.16 +/- 0.10 mag would increase this estimate to (m - M)(o) = 29.21 +/- 0.17 mag. C1 Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, IPAC, Pasadena, CA 91125 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston Creek, ACT 2611, Australia. Johns Hopkins Univ, Baltimore, MD 21218 USA. Space Telescope Inst, Baltimore, MD 21218 USA. Carnegie Observ, Pasadena, CA 91101 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Wisconsin, Madison, WI 53706 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon STX Corp, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Royal Greenwich Observ, Cambridge CB3 0EZ, England. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Stetson, PB (reprint author), Dominion Astrophys Observ, 5071 W Saanich Rd, Victoria, BC V8X 4M6, Canada. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 37 TC 97 Z9 97 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 491 EP 517 DI 10.1086/306443 PN 1 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500005 ER PT J AU Abel, T Stebbins, A Anninos, P Norman, ML AF Abel, T Stebbins, A Anninos, P Norman, ML TI First structure formation. II. Cosmic string plus hot dark matter models SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic strings; cosmology : theory; elementary particles; hydrodynamics ID HYDROGEN MOLECULES; NEUTRINOS; OBJECTS; SCHEME; WAKES AB We examine the structure of baryonic wakes in the cosmological fluid that would form behind grand unified theory-scale cosmic strings at early times (redshifts z greater than or similar to 100) in a neutrino-dominated universe. We show, using simple analytical arguments as well as one- and two-dimensional hydrodynamical simulations, that these wakes will not be able to form interesting cosmological objects before the neutrino component collapses. The width of the baryonic wakes (less than or similar to 10 kpc comoving) is smaller than the scale of wiggles on the strings and is probably not enhanced by the wiggliness of the string network. C1 Univ Illinois, Natl Ctr Supercomp Applicat, Lab Computat Astrophys, Urbana, IL 61801 USA. Max Planck Inst Astrophys, D-85748 Garching, Germany. Fermi Natl Accelerator Lab, NASA, Astrophys Ctr, Batavia, IL 60510 USA. RP Abel, T (reprint author), Univ Illinois, Natl Ctr Supercomp Applicat, Lab Computat Astrophys, 405 N Mathews Ave, Urbana, IL 61801 USA. EM abel@mpa-garching.mpg.de; stebbins@fnal.gov; panninos@ncsa.uiuc.edu; norman@ncsa.uiuc.edu NR 33 TC 7 Z9 7 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 530 EP 534 DI 10.1086/306413 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500007 ER PT J AU Xu, C Hacking, PB Fang, F Shupe, DL Lonsdale, CJ Lu, NY Helou, G Stacey, GJ Ashby, MLN AF Xu, C Hacking, PB Fang, F Shupe, DL Lonsdale, CJ Lu, NY Helou, G Stacey, GJ Ashby, MLN TI Emission features and source counts of galaxies in the mid-infrared SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : luminosity function, mass function; galaxies : photometry; galaxies : statistics; infrared : galaxies ID STAR-FORMATION HISTORY; HUBBLE DEEP FIELD; INTERSTELLAR DUST; REDSHIFT SURVEY; SMALL GRAINS; WIDE-FIELD; EVOLUTION; ISOCAM; SPECTROPHOTOMETRY; MODELS AB In this work we incorporate the newest Infrared Space Observatory (ISO) results on the mid-infrared spectral energy distributions (MIR SEDs) of galaxies into models for the number counts and redshift distributions of MIR surveys. A three-component model, with empirically determined MIR SED templates of (1) a cirrus/photodissociation region component, (2) a starburst component, and (3) an active galactic nucleus (AGN) component, is developed for infrared (3-120 mu m) SEDs of galaxies. The model includes a complete IRAS 25 mu m selected sample of 1406 local galaxies (z less than or equal to 0.1). Results based on these 1406 spectra show that the MIR emission features cause significant effects on the redshift dependence of the K-corrections for fluxes in the WIRE 25 mu m band and ISOCAM 15 mu m band. This in turn will affect deep counts and redshift distributions in these two bands, as shown by the predictions of two evolution models [a luminosity evolution model with L proportional to (1 + z)(3) and a density evolution model with rho proportional to (1 + z)(4)]. Th, dips and bumps on curves of MIR number counts, caused by the emission features, should be useful indicators of the evolution mode. The strong emission features at similar to 6-8 mu m will help the detections of relatively high redshift (z similar to 2) galaxies in MIR surveys. On the other hand, determinations of the evolutionary rate based on the slope of source counts and studies on the large-scale structures using the redshift distribution of MIR sources will have to treat the effects of the MIR emission features carefully. We have also estimated a 15 mu m local luminosity function from the predicted 15 mu m fluxes of the 1406 galaxies using the bivariate (15 mu m vs. 25 mu m luminosities) method. This luminosity function will improve our understanding of the ISOCAM 15 mu m surveys. C1 CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Smithsonian Astrophys Observ, Opt & Infared Astron Div, Cambridge, MA 02138 USA. RP Xu, C (reprint author), CALTECH, Jet Prop Lab, Ctr Infrared Proc & Anal, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 68 TC 75 Z9 75 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 576 EP 589 DI 10.1086/306424 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500012 ER PT J AU Turner, TJ George, IM Nandra, K AF Turner, TJ George, IM Nandra, K TI X-ray signatures of an ionized reprocessor in the Seyfert galaxy Ton S180 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Ton S180); galaxies : nuclei; galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; FE-II EMISSION; IMAGING SPECTROMETER; VARIABILITY; REFLECTION; CONTINUUM; RADIATION; ACCRETION; QUASARS; SPECTRA AB We discuss the hard X-ray properties of the Seyfert galaxy Ton S180 based on the analysis of ASCA data. We find the X-ray flux varied by a factor similar to 2 on a timescale of a few thousand seconds. The source showed a significantly higher amplitude of variability in the 0.5-2 keV band than in the 2-10 keV band. The continuum is adequately parameterized as a Gamma similar to 2.5 power law across the 0.6-10 keV band. We confirm the recent discovery of an emission line of high equivalent width due to Fe K shell emission from highly ionized material. These ASCA data show the Fe line profile to be broad and asymmetric, and they tentatively suggest it is stronger during the X-ray hares, which is consistent with an origin from the inner parts of an accretion disk. The X-ray spectrum is complex below 2 keV, possibly because of emission from a blend of soft X-ray lines, which would support the existence of an ionized reprocessor most likely due to a relatively high accretion rate in this source. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Turner, TJ (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Code 660, Greenbelt, MD 20771 USA. NR 38 TC 44 Z9 44 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 648 EP 656 DI 10.1086/306434 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500018 ER PT J AU Stapelfeldt, KR Burrows, CJ Krist, JE Watson, AM Ballester, GE Clarke, JT Crisp, D Evans, RW Gallagher, JS Griffiths, RE Hester, JJ Hoessel, JG Holtzman, JA Mould, JR Scowen, PA Trauger, JT Westphal, JA AF Stapelfeldt, KR Burrows, CJ Krist, JE Watson, AM Ballester, GE Clarke, JT Crisp, D Evans, RW Gallagher, JS Griffiths, RE Hester, JJ Hoessel, JG Holtzman, JA Mould, JR Scowen, PA Trauger, JT Westphal, JA TI Hubble Space Telescope imaging of the circumstellar nebulosity of T Tauri SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; ISM : jets and outflows; stars : imaging; stars : individual (T Tauri) ID YOUNG STELLAR OBJECTS; MAIN-SEQUENCE STARS; BINARY-SYSTEM; IMAGES; WFPC2; DISCOVERY; COMPANION; ENVELOPES; OUTFLOWS; SEARCH AB Short-exposure Planetary Camera images of T Tauri have been obtained using broadband filters spanning the wavelength range 0.55-0.80 mu m. The optically visible star lies very close to an are of reflection nebulosity. The are's northern arm extends approximately 5 " from the star, while its southwestern arm appears brighter and extends only 2 ". The are shows an approximate symmetry along an axis toward the west-northwest, the direction of Hind's Nebula and the blueshifted molecular outflow. The morphology of the reflected light is similar to models of scattered light within an illuminated, axisymmetric outflow cavity in a circumbinary envelope, viewed approximate to 45 degrees from the outflow axis. However, our model images do not successfully account for the amount of limb brightening that is seen. No optical counterpart to the infrared companion is seen to a limiting magnitude of V = 19.6, which suggests A(V) > 7 mag toward this source. There is no evidence for an optical tertiary, to a limiting Delta V = 5.1 mag fainter than the primary, at the position where such an object has been previously reported. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. European Space Agcy, Dept Space Sci, Div Astrophys, F-75738 Paris 15, France. Univ Nacl Autonoma Mexico, Inst Astron, Morelia 58090, Michoacan, Mexico. Univ Michigan, AOSS, Space Res Lab, Ann Arbor, MI 48109 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Stapelfeldt, KR (reprint author), CALTECH, Jet Prop Lab, MS 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM krs@wfpc2-mail.jpl.nasa.gov RI Stapelfeldt, Karl/D-2721-2012; Clarke, John/C-8644-2013 NR 32 TC 44 Z9 44 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 DEC 1 PY 1998 VL 508 IS 2 BP 736 EP 743 DI 10.1086/306422 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500030 ER PT J AU Canuto, VM AF Canuto, VM TI Turbulence in stars. II. Shear, stable stratification, and radiative losses SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; stars : interiors; turbulence ID DIRECT NUMERICAL-SIMULATION; REYNOLDS STRESS APPROACH; LARGE-EDDY SIMULATION; DYNAMICAL MODEL; ROTATING STARS; STELLAR EVOLUTION; CONVECTION; BUOYANCY; FLOWS; OCEAN AB For many years shear-driven turbulence was thought to provide sufficient turbulent mixing in stably stratified regions to explain stellar structure data. It has recently been argued that the mixing is too weak and that alternative mixing mechanisms are required. The conclusion is predicated, among others, on the key assumption that turbulence exists only for Ri < Ri(cr) = 1/4. This result follows from linear stability analysis and contradicts a variety of data. We suggest a new definition of Ri(cr): it is the value of Ri at which the turbulent kinetic energy vanishes. We find that for Pe > 1 (no radiative losses) Ri(cr) similar to 1, while for Pe < 1 (important radiative losses) Ri(cr) similar to Pe(-1) greater than or equal to 1. Thus, we find more mixing. We present an internally consistent treatment of all the physical variables, individually and collectively, and show that turbulence is alive and well above the Ri > 1/4 limit. However, without a specific application of the model to a stellar case, we cannot claim that the new model will provide the mixing required by stellar data. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 60 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 767 EP 779 DI 10.1086/306427 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500035 ER PT J AU Contopoulos, I Kazanas, D AF Contopoulos, I Kazanas, D TI A cosmic battery SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; stars : formation; stars : magnetic fields; Sun : magnetic fields ID ADVECTION-DOMINATED ACCRETION; MAGNETIC-FIELDS; BLACK-HOLES; AMBIPOLAR DIFFUSION; CLOUD CORES; JETS; FORMULATION; GENERATION; RADIO; DISKS AB We show that the Poynting-Robertson drag effect in an optically thin advection-dominated accretion flow around active gravitating objects generates strong azimuthal electric currents that give rise to astrophysically significant magnetic fields. Although the mechanism is most effective in accreting compact objects, it also seems very promising as a way to account for the generation of stellar dipolar fields during the late protostellar collapse phase, when the star approaches the main sequence. C1 Univ Crete, Dept Phys, Heraklion 71003, Greece. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Contopoulos, I (reprint author), Univ Crete, Dept Phys, POB 2208, Heraklion 71003, Greece. NR 30 TC 36 Z9 36 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP 859 EP 863 DI 10.1086/306426 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MC UT WOS:000077780500042 ER PT J AU Brown, TM Ferguson, HC Deharveng, JM Jedrzejewski, RI AF Brown, TM Ferguson, HC Deharveng, JM Jedrzejewski, RI TI Measurements of far-UV emission from elliptical galaxies at z=0.375 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : abundances; galaxies : evolution; galaxies : stellar content; ultraviolet : galaxies; ultraviolet : stars ID SPECTROPHOTOMETRIC STANDARD STARS; ENERGY-DISTRIBUTIONS; STELLAR POPULATIONS; REDSHIFT CLUSTERS; S0 GALAXIES; ULTRAVIOLET; SPECTRA; PHOTOMETRY; EVOLUTION; ORIGIN AB The "UV upturn" is a sharp rise in spectra of elliptical galaxies shortward of rest-frame 2500 Angstrom. It is a ubiquitous phenomenon in nearby giant elliptical galaxies and is thought to arise primarily from low-mass evolved stars on the extreme horizontal branch and beyond. Models suggest that the UV upturn is a very strong function of age for these old stellar populations, increasing as the galaxy gets older. In some models, the change in UV/optical flux ratio is a factor of 25 over timescales of less than 3 Gyr. To test the predictions for rapid evolution of the UV upturn, we have observed a sample of normal elliptical galaxies in the z = 0.375 cluster Abell 370 with the Faint Object Camera aboard the Hubble Space Telescope. A combination of two long-pass filters was used to isolate wavelengths shortward of rest-frame 2700 Angstrom, providing a measurement of the UV upturn at a lookback time of approximately 4 Gyr. Surprisingly, the four elliptical galaxies observed show a range of UV upturn strength that is similar to that seen in nearby elliptical galaxies, with an equivalent m(1550) - V color ranging from 2.9 to 3.4 mag. Our result is inconsistent with some models for the UV upturn; other models are consistent only for a high redshift of formation (z(f) greater than or equal to 4). C1 NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CNRS, Astron Spatiale Lab, F-13376 Marseille 12, France. RP Brown, TM (reprint author), NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. EM tbrown@pulsar.gsfc.nasa.gov; ferguson@stsci.edu; jmd@astrsp-mrs.fr; rilj@stsci.edu OI Brown, Thomas/0000-0002-1793-9968 NR 32 TC 20 Z9 20 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 DEC 1 PY 1998 VL 508 IS 2 BP L139 EP L142 DI 10.1086/311743 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MD UT WOS:000077780600006 ER PT J AU Sahu, KC Sahu, MS AF Sahu, KC Sahu, MS TI Spectroscopy of MACHO 97-SMC-1: Self-lensing within the Small Magellanic Cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; galaxies : individual (Small Magellanic Cloud); Galaxy : halo ID MICROLENSING EVENTS; STARS; HALO; FIELD; DISK AB More than a dozen microlensing events have been detected so far toward the LMC, and two have been detected toward the SMC. If all of the lenses are in the Galactic halo, both the LMC and the SMC events are expected to have similar timescales. However, the first event toward the SMC, MACHO 97-SMC-1, had a timescale of 123 days, which is much larger than the typical timescale for the LMC events. Since the observed timescale of the SMC event would need the mass of the halo lens to be similar to 3 M-. it has been argued earlier that the lens must be within the SMC, which we spectroscopically confirm in this Letter. From optical depth estimates, we first show that the stars within the SMC play a dominant role as gravitational lenses and can fully account for the observed microlensing events, mainly due to its large physical depth. We also show that if the lenses are within the Magellanic Clouds, then the SMC events should be longer in duration than the LMC events, a fact that is consistent with the observations. The timescale of the event implies that the mass of the lens is greater than or similar to 2 M-. if it is in the Milky Way disk or halo, in which case the lens, if it is a normal star, is expected to be bright and should reveal itself in the spectrum. Here, we present an optical spectrum of MACHO 97-SMC-1 obtained in 1997 May that shows that the source is a main-sequence B star. There is no trace of any contribution from the lens, which suggests that the lens is not in the Milky Way disk or halo but is a low-mass star within the SMC. The other alternative, that the lens could be a black hole in the Galactic halo, cannot be ruled out from the spectrum alone, but this is disfavored by the timescales of the I,MC events. It is worth noting here that MACHO SMC-98-1 is the only other observed event toward the SMC. This was a binary lens event for which the caustic crossing timescale as observed by the PLANET, MACHO, EROS, and OGLE collaborations suggests that the lens is within the SMC. Furthermore, the only LMC event for which we have independent information on the location of the lens is the binary lens event MACHO LMC-9, where the caustic crossing timescale suggests the lens to be within the LMC. Thus, our current knowledge of the events indicates that all three microlensing events toward the Magellanic Clouds for which we have independent knowledge of the location of the lenses are due to self-lensing within the Magellanic Clouds. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ USA. RP Sahu, KC (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 36 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1998 VL 508 IS 2 BP L147 EP L150 DI 10.1086/311746 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 152MD UT WOS:000077780600008 ER PT J AU Sloan, GC Price, SD AF Sloan, GC Price, SD TI The infrared spectral classification of oxygen-rich dust shells SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE circumstellar matter; infrared : stars; stars : AGB and post-AGB; stars : fundamental parameters; stars : mass loss ID LOW-RESOLUTION SPECTRA; M-MIRA VARIABLES; EMISSION FEATURES; SILICATE DUST; CIRCUMSTELLAR DUST; IRAS SOURCES; LRS SPECTRA; CALIBRATION; MICRONS; STARS AB This paper presents infrared spectral classifications for a flux-limited sample of 635 optically identified oxygen-rich variables including supergiants and sources on the asymptotic giant branch (AGB). Several classes of spectra from oxygen-rich dust exist, and these can be arranged in a smoothly varying sequence of spectral shapes known as the silicate dust sequence. Classification based on this sequence reveals several dependencies of the dust emission on the properties of the central star. Nearly all S stars show broad emission features from alumina dust, while most of the supergiants exhibit classic features from amorphous silicate dust. Mira variables with symmetric light curves generally show broad alumina emission, while those with more asymmetric light curves show classic silicate emission. These differences may arise from differences in the photospheric C/O ratio. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Phillips Lab, PL GPOB, Bedford, MA 01731 USA. RP Sloan, GC (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 34 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD DEC PY 1998 VL 119 IS 2 BP 141 EP 158 DI 10.1086/313156 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 150VW UT WOS:000077687300002 ER PT J AU Feibelman, WA AF Feibelman, WA TI The IUE spectra of three optically narrow-line O VI planetary nebulae: NGC 1501, IC 1747, and IC 1297 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE planetary nebulae : individual (NGC 1501 IC 1747, IC 1297) ID CENTRAL STARS; NUCLEI; RATIOS AB The IUE spectra of NGC 1501, IC 1747, and IC 1297 have been analyzed with the Final Archive NEWSIPS processing and contain a large amount of new information. The UV spectra of the first two objects have received very little attention up to now, although they belong to the astrophysically rare but important group of planetary nebulae that exhibit O VI, O VII, and O VIII emission lines. Terminal wind velocities in the range -2500 < V-infinity < -3880 km s(-1) were derived for the three objects from P Cygni profiles of the O V lambda 1371 and C IV lambda 1549 lines and are thought to be the first detection of stellar winds for these planetaries. Electron densities for IC 1297 have been redetermined, and more than 60 emission lines were identified. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Feibelman, WA (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 22 TC 8 Z9 8 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD DEC PY 1998 VL 119 IS 2 BP 197 EP 205 DI 10.1086/313160 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 150VW UT WOS:000077687300006 ER PT J AU Brosius, JW Davila, JM Thomas, RJ AF Brosius, JW Davila, JM Thomas, RJ TI Solar active region and quiet-sun extreme-ultraviolet spectra from SERTS-95 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE instrumentation : spectrographs; Sun : activity; Sun : corona; Sun : UV radiation ID LYMAN-ALPHA; SPECTROGRAPH; WAVELENGTHS; DIAGNOSTICS; ANGSTROMS; EMISSION; FLARES; LINES; VLA AB Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph was flown on 1995 May 15 (SERTS-95), carrying a multilayer-coated toroidal diffraction grating that enhanced the instrumental sensitivity in its second-order wave band (171-225 Angstrom). Spectra and spectroheliograms of NOAA active region 7870 (N09 W22) were obtained in this wave band with a spectral resolution (instrumental FWHM) similar to 30 m Angstrom and in the first-order wave band (235-335 Angstrom) with a spectral resolution similar to 55 m Angstrom. Spectra and spectroheliograms of quiet-Sun areas northeast of the active region were also obtained. We derived the SERTS-95 relative radiometric calibration directly from flight data by means of density- and temperature-insensitive line intensity ratios. Most theoretical values for such ratios were obtained from the CHIANTI database. A total of 44 different lines were used to derive the relative radiometric calibration in the two spectral orders, most of them coming from seven (Fe X-Fe XVI) of the nine (Fe IX-Fe XVII) observed ionization stages of iron. The resulting relatively calibrated line intensities agree well with their corresponding normalized theoretical values. This supports the overall accuracy of the atomic physics parameters and demonstrates the power of the technique. The present work extends earlier work by Brosius, Davila, & Thomas, who determined the SERTS-95 second-order response using this technique. Many of the ratios employed here can be used to carry out a similar calibration exercise on spectra from the Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory (SOHO). We placed the line intensities onto an absolute scale by forcing our quiet-Sun He II lambda 303.8 + Si XI lambda 303.3 intensity to match that from previous observations. The resulting active region and quiet-Sun absolutely calibrated line lists contain 127 and 20 lines, respectively. Active region densities derived from density-sensitive line intensity ratios of Fe X, XI, XIII, and XIV are mutually consistent with log n(e) similar to 9.4 +/- 0.2; densities derived from Fe XII are significantly greater (log n(e) similar to 10). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Brosius, JW (reprint author), STX Corp, 4400 Forbes Blvd, Lanham, MD 20706 USA. NR 36 TC 73 Z9 74 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD DEC PY 1998 VL 119 IS 2 BP 255 EP 276 DI 10.1086/313163 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 150VW UT WOS:000077687300009 ER PT J AU Dunagan, N Greenleaf, JE Cisar, CJ AF Dunagan, N Greenleaf, JE Cisar, CJ TI Thermoregulatory effects of caffeine ingestion during submaximal exercise in men SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID METABOLIC RESPONSES; PROLONGED EXERCISE; COLD; PERFORMANCE AB Background: The exclusive effect of caffeine ingestion on exercise thermoregulation is unclear; data indicate that caffeine may have a positive effect, a negative effect, or no effect. Methods: Rectal (TRE) and mean skin ((T) over bar SK) temperatures, skin heat conductance (HSK), and sweat rate ((M)over dot SW) were measured during 30 min of rest and subsequent 70 min of submaximal cycle-ergometer exercise (67% (V)over dot O(2)PEAK) in 11 aerobically conditioned men (mean +/- SD 29 +/- 6 yr, 49 +/- 6 mL.min(-1).kg(-1) (V)over dot O(2)PEAK) under two conditions: a caffeine (10 mg.kg(-1)) ingestion (CI) session and a noncaffeine ingestion (NCI) control session. Results: There were no significant differences in physiological or thermoregulatory parameters during exercise: (X) over bar (+/-SE) end exercise levels fur the NCI and CI sessions, respectively, were (V)over dot O-2 = 2.50 +/- 0.09 vs. 2.55 +/- 0.09 L.min(-1); heart rate = 145 +/- 7 vs. 145 +/- 5 bpm; HSK = 30 +/- 3 vs. 28 +/- 3 kcal.m(-2).h(-1).degrees C-1; (M)over dot SW = 393 +/- 35 vs. 378 +/- 36 g.m(-2).h(-1); and TRE = 38.3 +/- 0.2 vs. 38.4 +/- 0.1 degrees C. Control (T) over bar SK was lower than that fur CI by 0.4 to 0.5 degrees C at rest and during exercise. Conclusion: Ingestion of a high level (10 mg.kg(-1)) of caffeine has no effect on skin heat conductance, sweating, or the rate of increase and final level of rectal temperature during moderate, submaximal leg exercise. C1 NASA, Ames Res Ctr, Gravitat Res Branch 239 11, Lab Human Environm Physiol, Moffett Field, CA 94035 USA. San Jose State Univ, Exercise Physiol Lab, San Jose, CA 95192 USA. RP Greenleaf, JE (reprint author), NASA, Ames Res Ctr, Gravitat Res Branch 239 11, Lab Human Environm Physiol, Moffett Field, CA 94035 USA. NR 25 TC 10 Z9 10 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 DEC PY 1998 VL 69 IS 12 BP 1178 EP 1181 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 142DF UT WOS:000077184100009 PM 9856543 ER PT J AU Jaunky, N Knight, NF Ambur, DR AF Jaunky, N Knight, NF Ambur, DR TI Buckling analysis of anisotropic variable-curvature panels and shells SO COMPOSITE STRUCTURES LA English DT Article ID NONCIRCULAR CYLINDRICAL-SHELLS; FREE-VIBRATION; CROSS-SECTION AB A buckling formulation for anisotropic variable-curvature panels is presented in this paper. The variable-curvature panel is assumed to consist of two or more panels of constant curvature where each panel may have a different curvature. Bezier functions are used as Ritz functions. Displacement (C-0), and slope (C-1) continuities between segments are imposed by manipulation of the Bezier control points. A first-order shear-deformation theory is used in the buckling formulation. Results obtained from the present formulation are compared with those from finite element simulations and are found to be in good agreement. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Old Dominion Univ, Dept Aerosp Engn, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23681 USA. RP Knight, NF (reprint author), MRJ Technol Solut, 303 Heavens Way, Yorktown, VA 23693 USA. NR 21 TC 0 Z9 0 U1 0 U2 1 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 DEC PY 1998 VL 43 IS 4 BP 321 EP 329 DI 10.1016/S0263-8223(98)00118-4 PG 9 WC Materials Science, Composites SC Materials Science GA 175DP UT WOS:000079077800005 ER PT J AU Decyk, VK Norton, CD Szymanski, BK AF Decyk, VK Norton, CD Szymanski, BK TI How to support inheritance and run-time polymorphism in Fortran 90 SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article AB Fortran 90 does not support automatic inheritance and run-time polymorphism as language mechanisms. This paper discusses techniques for software emulation of inheritance and polymorphism in Fortran 90, which simplifies the implementation of an object-oriented programming style in Fortran 90. (C) 1998 Elsevier Science B.V. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Rensselaer Polytech Inst, Dept Comp Sci, Troy, NY 12180 USA. RP Decyk, VK (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RI Szymanski, Boleslaw/A-9121-2009 OI Szymanski, Boleslaw/0000-0002-0307-6743 NR 10 TC 26 Z9 26 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD DEC 1 PY 1998 VL 115 IS 1 BP 9 EP 17 DI 10.1016/S0010-4655(98)00101-5 PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 145AF UT WOS:000077348200002 ER PT J AU Wan, M Bryson, S Kaufman, A AF Wan, M Bryson, S Kaufman, A TI Boundary cell-based acceleration for volume ray casting SO COMPUTERS & GRAPHICS-UK LA English DT Article DE scientific visualization; fast volume rendering; incremental computation; projection template; 2D scan conversion AB Several effective acceleration techniques for volume rendering offer efficient means to skip over empty space, providing significant speedup without affecting image quality. The effectiveness of such an approach depends on its ability to accurately estimate the object boundary inside a volume with minimal computational overhead. We propose a novel boundary cell-based acceleration technique for ray casting which skips over empty space by accurately calculating the intersection distance for each ray. Very short distance estimation time is achieved by exploiting a projection template to calculate the parallel-projection values of each boundary cell and the coherency of adjacent cells. Since no hardware acceleration is used, the projection procedure can also be efficiently parallelized. Experimental results are provided to demonstrate the performance of our new algorithm. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 SUNY Stony Brook, Ctr Visual Comp, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Comp Sci, Stony Brook, NY 11794 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP SUNY Stony Brook, Ctr Visual Comp, Stony Brook, NY 11794 USA. NR 14 TC 7 Z9 14 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0097-8493 EI 1873-7684 J9 COMPUT GRAPH-UK JI Comput. Graph.-UK PD DEC PY 1998 VL 22 IS 6 BP 715 EP 721 DI 10.1016/S0097-8493(98)00070-3 PG 7 WC Computer Science, Software Engineering SC Computer Science GA 167PE UT WOS:000078641800009 ER PT J AU Sogard, SM Olla, BL AF Sogard, SM Olla, BL TI Contrasting behavioral responses to cold temperatures by two marine fish species during their pelagic juvenile interval SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE fish behavior; diel patterns; activity; temperature ID POLLOCK THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; VERTICAL-DISTRIBUTION; FOOD; THERMOCLINES; PATTERNS; GROWTH; PALLAS; LIGHT AB Motor activity of juvenile walleye pollock, Theragra chalcogramma, and sablefish, Anoplopoma fimbria, was monitored in the laboratory during high and low light levels under a changing temperature regime over a 5 d period. Water temperatures were ambient (12 degrees C) for the first 24 h of observation, rapidly lowered to 3 degrees C for the next 48 h, then raised back to 12 degrees C for the final 48 h. We hypothesized that the fishes' behavior would either follow a simple bioenergetic response of lowered activity associated with reduced metabolic rates at the colder temperature, or an avoidance response, with increased activity at decreased temperatures. Results for walleye pollock were consistent with a bioenergetic response, with activity decreasing in the presence of cold water under both high and low light levels, then returning to initial levels when temperatures increased. The response of sablefish, in contrast, indicated avoidance of cold temperatures, depending on light level. During high light, when sablefish were typically highly active, cold water induced a slight but insignificant decrease in activity. At low light, however, the presence of cold water caused a marked increase in sablefish movement through the experimental tanks, with a seven fold increase in the measured index of activity. When water temperatures were raised back to 12 degrees C, sablefish activity at low light returned to its normal, minimal level. The sharp increase in activity of sablefish in cold water, followed by a decrease in activity when the temperature was raised to pre-test levels, is suggestive of an avoidance response. The contrasting responses of the two species to thermal changes are consistent with their separate life history patterns and natural distributions. C1 Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. RP Sogard, SM (reprint author), Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. EM susan.sogard@hmsc.orst.edu NR 34 TC 9 Z9 9 U1 3 U2 11 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD DEC PY 1998 VL 53 IS 4 BP 405 EP 412 DI 10.1023/A:1007485417486 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 144KR UT WOS:000077314200007 ER PT J AU Able, KW Manderson, JP Studholme, AL AF Able, KW Manderson, JP Studholme, AL TI The distribution of shallow water juvenile fishes in an urban estuary: The effects of manmade structures in the lower Hudson river SO ESTUARIES LA English DT Article ID MOVEMENTS; TURBIDITY AB The objective of this study was to determine what effect, if any, large pile-supported platforms (piers) have on the habitat distribution and abundance of juvenile fishes. Trapping techniques were used in 1993 and 1994 under piers, in pile fields, and in open-water habitat types in shallow areas (<5 m) in the lower Hudson River estuary (40 degrees 44'N, 70 degrees 01'W). Nearly 1500 fishes, mostly juveniles, representing 24 species were collected in 1865 trap-days from May through October in the 2-yr study. The presence of relatively large numbers of young-of-the-year (YOY) fish during both years lends support to the idea that shallow areas in the lower Hudson River estuary currently function as nursery habitats for a variety of fishes. Two seasonal assemblages were apparent, but their composition varied somewhat between years. Microgadus tomcod and Pseudopleuronectes americanus YOY dominated an early summer assemblage (May-July) while large numbers of YOY Morone saxatilis were collected as part of a late summer assemblage (August-September). The effects of habitat type on fish assemblage structure were significant during both years. Fish abundance and species richness were typically low under piers; YOY fishes were rare and Anguilla rostrata accounted for a large proportion of the total catch. In contrast, YOY fishes dominated collections at pile field and open-water stations, where abundance and species richness were high. These results indicate that habitat quality under the platforms of large piers (>20,000 m(2)) is probably poor for YOY fishes when compared with nearby pile field and open-water habitat types. C1 Rutgers State Univ, Marine Field Stn, Inst Marine & Coastal Sci, Tuckerton, NJ 08087 USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Able, KW (reprint author), Rutgers State Univ, Marine Field Stn, Inst Marine & Coastal Sci, 800 Great Bay Blvd,132 Great Bay Blvd, Tuckerton, NJ 08087 USA. EM able@arctic.rutgers.edu NR 55 TC 44 Z9 44 U1 2 U2 11 PU ESTUARINE RESEARCH FEDERATION PI PORT REPUBLIC PA 2018 DAFFODIL, PO BOX 510, PORT REPUBLIC, MD 20676 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD DEC PY 1998 VL 21 IS 4B BP 731 EP 744 DI 10.2307/1353277 PG 14 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 169KE UT WOS:000078746300007 ER PT J AU McComas, DJ Bame, SJ Barker, PL Delapp, DM Feldman, WC Gosling, JT Santiago, E Skoug, RM Tokar, RL Riley, P Phillips, JL Griffee, JW AF McComas, DJ Bame, SJ Barker, PL Delapp, DM Feldman, WC Gosling, JT Santiago, E Skoug, RM Tokar, RL Riley, P Phillips, JL Griffee, JW TI An unusual coronal mass ejection: First Solar Wind Electron, Proton, Alpha Monitor (SWEPAM) results from the Advanced Composition Explorer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ABUNDANCE AB This paper reports the first scientific results from the Solar Wind Electron Proton Alpha Monitor (SWEPAM) instrument on board the Advanced Composition Explorer (ACE) spacecraft. We analyzed a coronal mass ejection (CME) observed in the solar wind using data from early February, 1998. This event displayed several of the common signatures of CMEs, such as counterstreaming halo electrons and depressed ion and electron temperatures, as well as some unusual features. During a portion of the CME traversal, SWEPAM measured a very large helium to proton abundance ratio. Other heavy ions, with a set of ionization states consistent with normal (1-2 x 10(6) IC) coronal temperatures, were proportionately enhanced at this time. These observations suggest a source for at least some of the CME material, where heavy ions are initially concentrated relative to hydrogen and then accelerated up into the solar wind, independent of their mass and first ionization potential. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Scibernet Inc, San Diego, CA 92121 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP McComas, DJ (reprint author), Univ Calif Los Alamos Natl Lab, D466, Los Alamos, NM 87545 USA. NR 14 TC 19 Z9 19 U1 1 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 DEC 1 PY 1998 VL 25 IS 23 BP 4289 EP 4292 DI 10.1029/1998GL900174 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400013 ER PT J AU Jost, H Loewenstein, M Pfister, L Margitan, JJ Chang, AY Salawitch, RJ Michelsen, HA AF Jost, H Loewenstein, M Pfister, L Margitan, JJ Chang, AY Salawitch, RJ Michelsen, HA TI Laminae in the tropical middle stratosphere: Origin and age estimation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB In situ measurements of N2O and O-3 aboard the Observations from the Middle Stratosphere (OMS) balloon payload in the tropics are presented. In November 1997 at 7 degrees S very distinct laminated structures in the N2O profile were observed in contrast to earlier studies based solely on O-3 profiles. The laminae probably are an observation of Rossby wave-breaking events that lead to transport of midlatitude air into the tropics. Using a photochemical model of the ozone response within those air parcels, their residence time in the tropics is estimated to be 4 to 6 weeks. In February 1997 at 7 degrees S a similar vertical profile of N2O revealed no mid-latitude laminae. We present dynamical arguments to support the existence of such laminae in November, but not in February. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. AER Inc, San Ramon, CA 94583 USA. RP Jost, H (reprint author), NASA, Ames Res Ctr, MS 245-5, Moffett Field, CA 94035 USA. EM hjost@mail.arc.nasa.gov RI Salawitch, Ross/B-4605-2009 OI Salawitch, Ross/0000-0001-8597-5832 NR 18 TC 18 Z9 18 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 DEC 1 PY 1998 VL 25 IS 23 BP 4337 EP 4340 DI 10.1029/1998GL900153 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400025 ER PT J AU Gierens, K Jensen, E AF Gierens, K Jensen, E TI A numerical study of the contrail-to-cirrus transition SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AIRCRAFT AB A numerical 2D-simulation of the transformation of a contrail in its vortex phase to a cirrus-like cloud during the dispersion phase has been performed using a model that handles both wake dynamics and ice microphysics. The contrail is located in an environment characterized by measured profiles of wind and temperature. The ambient humidity at cruise level slightly exceeds ice-saturation. The thermal structure of the atmosphere causes a strong vertical growth of the contrail cloud, even into a dry layer, until a stably stratified layer is reached. Thereafter the cloud expands mainly horizontally and after 30 min it eventually disappears because of entrainment of dry ambient air. C1 DLR Oberpfaffenhofen, Inst Phys Atmosphare, D-82234 Wessling, Germany. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gierens, K (reprint author), DLR Oberpfaffenhofen, Inst Phys Atmosphare, D-82234 Wessling, Germany. NR 17 TC 16 Z9 16 U1 0 U2 0 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 DEC 1 PY 1998 VL 25 IS 23 BP 4341 EP 4344 DI 10.1029/1998GL900151 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400026 ER PT J AU Wang, L Koblinsky, C Howden, S Beckley, B AF Wang, L Koblinsky, C Howden, S Beckley, B TI Intermittence and modulation of mesoscale variability SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID KUROSHIO EXTENSION; GEOSAT ALTIMETRY; NORTH-ATLANTIC; ENERGY AB We studied both the fast and slow modulation of mesoscale variability in the western Kuroshio Extension region (along track 119) by analyzing 4-year TOPEX/Poseidon altimetry data. Bulk of the mesoscale variability lies near the axis of the Kuroshio Extension and the western boundary current along the east coast of Japan. It is found that both the intensity and spreading of mesoscale variability in the frequency band has significant, both abrupt and slow, variations. The slow modulation may be mainly caused by low-frequency variation in the background mean flow, while the abrupt change is primarily due to strong nonlinear processes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wang, L (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 13 TC 4 Z9 4 U1 0 U2 0 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 DEC 1 PY 1998 VL 25 IS 23 BP 4365 EP 4368 DI 10.1029/1998GL900164 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400033 ER PT J AU Yueh, SH Kwok, R AF Yueh, SH Kwok, R TI Arctic sea ice extent and melt onset from NSCAT observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SYNTHETIC-APERTURE-RADAR AB NSCAT Ku-band microwave observations of the Arctic sea ice cover are described on their potential use for estimating ice extent and timing of spring melt. A simple comparative analysis of the NSCAT Arctic sea ice extent and high-resolution Radarsat imagery suggests that the SSM/I 25% ice concentration contour appears to be a good indicater of the winter Arctic ice edge. For spring melt-onset, a comparative study of NSCAT sea ice observations and NCEP/NCAR surface air temperature indicates that Ku-band backscatter of the snow cover over multiyear ice has a clear and steep change as the surface air temperature rises above freezing. This signature of melt onset should provide useful large-scale estimates of the dates of melt onset with spaceborne scatterometer date. A more extensive validation of the potential of this dataset is suggested. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yueh, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 6 TC 10 Z9 10 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 DEC 1 PY 1998 VL 25 IS 23 BP 4369 EP 4372 DI 10.1029/1998GL900080 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400034 ER PT J AU Rosenfield, JE Douglass, AR AF Rosenfield, JE Douglass, AR TI Doubled CO2 effects on NOy in a coupled 2D model SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERE; BANDS; OZONE AB Stratospheric NOy fields calculated using a zonally averaged interactive chemistry-radiation-dynamics model show significant sensitivity to the model CO2. Modeled upper stratospheric NOy decreases by about 15% in response to CO2 doubling, mainly due to the temperature decrease calculated to result from increased CO2 cooling. The abundance of atomic nitrogen, N, increases because the rate of the strongly temperature dependent reaction N + O-2 --> NO + O decreases at lower temperatures. Increased N leads to an increase in the loss of NOy which is controlled by the reaction N + NO --> N-2 + O. The decrease in NOy due to the lowered temperatures is partially compensated by changes in the residual circulation. In addition, the NOy reduction is shown to be sensitive to the NO photolysis rate. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Gen Sci Corp, Laurel, MD USA. RP Rosenfield, JE (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 916, Greenbelt, MD 20771 USA. RI Douglass, Anne/D-4655-2012 NR 13 TC 31 Z9 31 U1 0 U2 5 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 DEC 1 PY 1998 VL 25 IS 23 BP 4381 EP 4384 DI 10.1029/1998GL900147 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 143XG UT WOS:000077282400037 ER PT J AU Wood, EF Lettenmaier, DP Liang, X Lohmann, D Boone, A Chang, S Chen, F Dai, YJ Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchel, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC AF Wood, EF Lettenmaier, DP Liang, X Lohmann, D Boone, A Chang, S Chen, F Dai, YJ Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchel, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC TI The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) phase 2(c) Red-Arkansas River basin experiment: 1. Experiment description and summary intercomparisons SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT Project for Intercomparison of Landsurface Parameterization Schemes Workshop (PILPS) CY JUN, 1997 CL MELBOURNE, AUSTRALIA DE PILPS; land-surface parameterization; continental river basin modeling; energy/water balance; calibration of land-surface schemes; Red-Arkansas River basin AB 0Sixteen land-surface schemes participating in the Project for the Intercomparison of Land-surface Schemes (PILPS) Phase 2(c) were run using 10 years (1979-1988) of forcing data for the Red-Arkansas River basins in the Southern Great Plains region of the United States. Forcing data (precipitation, incoming radiation and surface meteorology) and land-surface characteristics (soil and vegetation parameters) were provided to each of the participating schemes. Two groups of runs are presented. (1) Calibration-validation runs, using data from six small catchments distributed across the modeling domain. These runs were designed to test the ability of the schemes to transfer information about model parameters to other catchments and to the computational grid boxes. (2) Base-runs, using data for 1979-1988, designed to evaluate the ability of the schemes to reproduce measured energy and water fluxes over multiple seasonal cycles across a climatically diverse, continental-scale basin. All schemes completed the base-runs but five schemes chose not to calibrate. Observational data (from 1980-1986) including daily river flows and monthly basin total evaporation estimated through an atmospheric budget analysis, were used to evaluate model performance. In general, the results are consistent with earlier PILPS experiments in terms of differences among models in predicted water and energy fluxes. The mean annual net radiation varied between 80 and 105 W m(-2) (excluding one model). The mean annual Bowen ratio varied from 0.52 to 1.73 (also excluding one model) as compared to the data-estimated value of 0.92. The run-off ratios varied from a low of 0.02 to a high of 0.41, as compared to an observed value of 0.15. In general, those schemes that did not calibrate performed worse, not only on the validation catchments, but also at the scale of the entire modeling domain. This suggests that further PILPS experiments on the value of calibration need to be carried out. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. USAF, Res Lab, Hanscom AFB, MA USA. NOAA, NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Univ Arizona, Inst Atmospher Phys, Tucson, AZ USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Oregon State Univ, Corvallis, OR 97331 USA. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Meteo France, CNRM, Toulouse, France. Univ New S Wales, Ctr Adv Numer Computat Engn & Sci, Sydney, NSW 2052, Australia. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. NOAA, GFDL, Princeton, NJ USA. Russian Acad Sci, Inst Geog, Moscow, Russia. Climate Res Branch, Atmospher Environm Serv, Toronto, ON, Canada. GKSS Forschungszentrum Geesthacht GmbH, Res Ctr, D-2054 Geesthacht, Germany. Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. RP Wood, EF (reprint author), Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. RI Dai, Yongjiu/D-1070-2010; Yang, Zong-Liang/B-4916-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; Duan, Qingyun/C-7652-2011; gusev, yugeniy/G-4711-2014; Shao, Yaping/G-3606-2013; Dai, Yongjiu/D-6261-2014; OI Wood, Eric/0000-0001-7037-9675; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; gusev, yugeniy/0000-0003-3886-2143; Shao, Yaping/0000-0002-2041-5479; Dai, Yongjiu/0000-0002-3588-6644; Habets, Florence/0000-0003-1950-0921 NR 17 TC 208 Z9 228 U1 1 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD DEC PY 1998 VL 19 IS 1-4 BP 115 EP 135 DI 10.1016/S0921-8181(98)00044-7 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 139GF UT WOS:000077019100008 ER PT J AU Liang, X Wood, EF Lettenmaier, DP Lohmann, D Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC AF Liang, X Wood, EF Lettenmaier, DP Lohmann, D Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC TI The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) phase 2(c) Red-Arkansas River basin experiment: 2. Spatial and temporal analysis of energy fluxes SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT Project for Intercomparison of Landsurface Parameterization Schemes Workshop (PILPS) CY JUN, 1997 CL MELBOURNE, AUSTRALIA DE PILPS; energy balance; land-surface models; Red-Arkansas River basin ID SOIL HEAT-FLUX; MODEL AB The energy components of sixteen Soil-Vegetation Atmospheric Transfer (SVAT) schemes were analyzed and intercompared using 10 years of surface meteorological and radiative forcing data from the Red-Arkansas River basin in the Southern Great Plains of the United States. Comparisons of simulated surface energy fluxes among models showed that the net radiation and surface temperature generally had the best agreement among the schemes. On an average (annual and monthly) basis, the estimated latent heat fluxes agreed (to within approximate estimation errors) with the latent heat fluxes derived from a radiosonde-based atmospheric budget method for slightly more than half of the schemes. The sensible heat fluxes had larger differences among the schemes than did the latent heat fluxes, and the model-simulated ground heat fluxes had large variations among the schemes. The spatial patterns of the model-computed net radiation and surface temperature were generally similar among the schemes, and appear reasonable and consistent with observations of related variables, such as surface air temperature. The spatial mean patterns of latent and sensible heat fluxes were less similar than for net radiation, and the spatial patterns of the ground heat flux vary greatly among the 16 schemes. Generally, there is less similarity among the models in the temporal (interannual) variability of surface fluxes and temperature than there is in the mean fields, even for schemes with similar mean fields. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. USAF, Res Lab, Hanscom, MA USA. NOAA, NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Macquarie Univ, Climat Impacts Ctr, Sydney, NSW 2109, Australia. Univ Arizona, Inst Atmospher Phys, Tucson, AZ USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Oregon State Univ, Corvallis, OR 97331 USA. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Meteo France, CNRM, Toulouse, France. Univ New S Wales, Ctr Adv Numer Computat Eng & Sci, Sydney, NSW 2052, Australia. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. NOAA, GFDL, Princeton, NJ USA. Russian Acad Sci, Inst Geog, Moscow, Russia. Climate Res Branch, Atmospher Environm Serv, Toronto, ON, Canada. RP Liang, X (reprint author), Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. RI Dai, Yongjiu/D-1070-2010; Yang, Zong-Liang/B-4916-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; Duan, Qingyun/C-7652-2011; gusev, yugeniy/G-4711-2014; Shao, Yaping/G-3606-2013; Dai, Yongjiu/D-6261-2014; OI Wood, Eric/0000-0001-7037-9675; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; gusev, yugeniy/0000-0003-3886-2143; Shao, Yaping/0000-0002-2041-5479; Dai, Yongjiu/0000-0002-3588-6644; Habets, Florence/0000-0003-1950-0921 NR 13 TC 73 Z9 82 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD DEC PY 1998 VL 19 IS 1-4 BP 137 EP 159 DI 10.1016/S0921-8181(98)00045-9 PG 23 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 139GF UT WOS:000077019100009 ER PT J AU Lohmann, D Lettenmaier, DP Liang, X Wood, EF Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC AF Lohmann, D Lettenmaier, DP Liang, X Wood, EF Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC TI The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) phase 2(c) Red-Arkansas River basin experiment: 3. Spatial and temporal analysis of water fluxes SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT Project for Intercomparison of Landsurface Parameterization Schemes Workshop (PILPS) CY JUN, 1997 CL MELBOURNE, AUSTRALIA DE PILPS; water balance; routing model; continental river basin modeling; Red-Arkansas River basin ID MODELS AB The water-balance components of 16 Soil-Vegetation Atmospheric Transfer (SVAT) schemes were evaluated by comparing predicted and observed streamflow, predicted evapotranspiration and evapotranspiration inferred from an atmospheric moisture budget analysis, and soil moisture storage changes for a seven-year period (1980-1986) using data from the Red-Arkansas River basins of the Southern Great Plains of the USA. The evaluations support the following suggestions: (a) The mean annual runoff of all models follows, at least generally, the strong climatic East-West gradient of precipitation, although most models predict too much runoff in the dry part of the basin. (b) The mean monthly storage change tends to be underestimated, even though all models capture reasonably well the seasonality of the evapotranspiration. (c) The wide range of conceptualizations used for generation of surface and subsurface runoff strongly affect runoff generation on seasonal, and shorter, time scales. Model responses to summer precipitation ranged from almost no summer runoff tone model) to the (more common) situation of persistent overprediction of summer runoff, especially in the driest part of the basin. (d) All models tended to underpredict evapotranspiration in summer and overpredict in winter. (e) Model-derived mean seasonal cycles of changes in soil moisture storage are qualitatively similar to those inferred from observations, but most models do not predict the decrease in April soil moisture storage and the increase in October that is inferred from observations. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. USAF, Res Lab, Hanscom AFB, MA USA. NOAA, NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Macquarie Univ, Climat Impacts Ctr, Sydney, NSW 2109, Australia. Univ Arizona, Inst Atmospher Phys, Tucson, AZ USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Oregon State Univ, Corvallis, OR 97331 USA. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Meteo France, CNRM, Toulouse, France. Univ New S Wales, Ctr Adv Numer Computat Engn & Sci, Sydney, NSW 2052, Australia. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. NOAA, GFDL, Princeton, NJ USA. Russian Acad Sci, Inst Geog, Moscow, Russia. Climate Res Branch, Atmospher Environm Serv, Toronto, ON, Canada. GKSS Forschungszentrum Geesthacht GmbH, Res Ctr, D-2054 Geesthacht, Germany. Ctr Ocean Land Atmospher Studies, Calverton, MD USA. RP Lohmann, D (reprint author), Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. RI Dai, Yongjiu/D-1070-2010; Yang, Zong-Liang/B-4916-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; Duan, Qingyun/C-7652-2011; gusev, yugeniy/G-4711-2014; Shao, Yaping/G-3606-2013; Dai, Yongjiu/D-6261-2014; OI Wood, Eric/0000-0001-7037-9675; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; gusev, yugeniy/0000-0003-3886-2143; Shao, Yaping/0000-0002-2041-5479; Dai, Yongjiu/0000-0002-3588-6644; Habets, Florence/0000-0003-1950-0921 NR 25 TC 135 Z9 144 U1 0 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD DEC PY 1998 VL 19 IS 1-4 BP 161 EP 179 DI 10.1016/S0921-8181(98)00046-0 PG 19 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 139GF UT WOS:000077019100010 ER PT J AU Potter, CS Klooster, SA AF Potter, CS Klooster, SA TI Interannual variability in soil trace gas (CO2, N2O, NO) fluxes and analysis of controllers on regional to global scales SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID NET PRIMARY PRODUCTION; ATMOSPHERIC CARBON-DIOXIDE; NDVI DATA SET; NITROUS-OXIDE; CLIMATE-CHANGE; BOREAL FOREST; TEMPORAL VARIABILITY; TROPICAL FOREST; EMISSIONS; ECOSYSTEMS AB Interannual variability in flux rates of biogenic trace gases must be quantified in order to understand the differences between short-term trends and actual long-term change in biosphere-atmosphere interactions. We simulated interannual patterns (1983-1988) of global trace gas fluxes from soils using the NASA Ames Research Center version of the Carnegie-Ames-Stanford Approach (CASA) model in a transient simulation mode. This ecosystem model has been calibrated for simulations driven by satellite vegetation index data from the National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer over the mid-1980s, The predicted interannual pattern of soil heterotropic CO2 emissions indicates that relatively large increases in global carbon flux from soils occurred about 3 years following the strong El Nino-Southern Oscillation event of 1983, Results for the years 1986 and 1987 showed an annual increment of +1 Pg (10(15) g) C-CO2 emitted from soils, which tended to dampen the estimated global increase in net ecosystem production with about a 2-year lag period relative to plant carbon fixation. Zonal discrimination of model results implies that 80-90% of the yearly positive increments in soil CO2 emission during 1986-1987 were attributable to soil organic matter decomposition in the low latitudes (between 30 degrees N and 30 degrees S). Soils of the northern middle-latitude zone (between 30 degrees and 60 degrees N) accounted for the residual of these annual increments. Total annual emissions of nitrogen trace gases (N2O and NO) from soils were estimated to vary from 2 to 4% over the time period modeled, a level of variability that is consistent with predicted interannual fluctuations in global soil CO2 fluxes. Interannual variability of precipitation in tropical and subtropical zones (30 degrees N to 20 degrees S) appeared to drive the dynamic inverse relationship between higher annual emissions of NO versus emissions of N2O. Global mean emission rates from natural (heterotrophic) soil sources over the period modeled (1983-1988) were estimated at 57.1 Pg C-CO2 yr(-1), 9.8 Tg (10(12) g) N-NO yr(-1), and 9.7 Tg N-N2O yr(-1). Chemical fertilizer contributions to global soil N gas fluxes were estimated at between 1.3 to 7.3 Tg N-NO yr(-1) and 1.2 re 4.0 Tg N-N2O yr(-1). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Seaside, CA 93955 USA. RP Potter, CS (reprint author), NASA, Ames Res Ctr, Mail Stop 242-4, Moffett Field, CA 94035 USA. NR 49 TC 36 Z9 37 U1 0 U2 17 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 DEC PY 1998 VL 12 IS 4 BP 621 EP 635 DI 10.1029/98GB02425 PG 15 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 148BZ UT WOS:000077533900007 ER PT J AU Rapalee, G Trumbore, SE Davidson, EA Harden, JW Veldhuis, H AF Rapalee, G Trumbore, SE Davidson, EA Harden, JW Veldhuis, H TI Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID ATMOSPHERIC CO2; BALANCE; PEATLANDS; BOG AB Boreal forests and wetlands are thought to be significant carbon sinks, and they could become net C sources as the Earth warms. Most of the C of boreal forest ecosystems is stored in the moss layer and in the soil. The objective of this study was to estimate soil C stocks (including moss layers) and rates of accumulation and loss for a 733 km(2) area of the BOReal Ecosystem-Atmosphere Study site in northern Manitoba, using data from smaller-scale intensive field studies. A simple process-based model developed from measurements of soil C inventories and radiocarbon was used to relate soil C storage and dynamics to soil drainage and forest stand age. Soil C stocks covary with soil drainage class, with the largest C stocks occurring in poorly drained sites. Estimated rates of soil C accumulation or loss are sensitive to the estimated decomposition constants for the large pool of deep soil C, and improved understanding of deep soil C decomposition is needed. While the upper moss layers regrow and accumulate C after fires, the deep C dynamics vary across the landscape, from a small net sink to a significant source. Estimated net soil C accumulation, averaged for the entire 733 km(2) area, was 20 g C m(-2) yr(-1) (28 g C m(-2) yr(-1) accumulation in surface mosses offset by 8 g C m(-2) yr(-1) lost from deep C pools) in a year with no fire. Most of the C accumulated in poorly and very poorly drained soils (peatlands and wetlands). Burning of the moss layer in only 1% of uplands would offset the C stored in the remaining 99% of the area. Significant interannual variability in C storage is expected because of the irregular occurrence of fire in space and time. The effects of climate change and management on fire frequency and on decomposition of immense deep soil C stocks are key to understanding future C budgets in boreal forests. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Woods Hole Res Ctr, Woods Hole, MA 02543 USA. US Geol Survey, Menlo Park, CA 94025 USA. Univ Manitoba, Agr & Agri Food Canada, Brandon Res Ctr, Manitoba Land Resource Unit, Winnipeg, MB R3T 2N2, Canada. RP Rapalee, G (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. RI Trumbore, Susan/B-1948-2013; Davidson, Eric/K-4984-2013 OI Davidson, Eric/0000-0002-8525-8697 NR 39 TC 84 Z9 88 U1 9 U2 35 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 DEC PY 1998 VL 12 IS 4 BP 687 EP 701 DI 10.1029/98GB02336 PG 15 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 148BZ UT WOS:000077533900011 ER PT J AU Sada, PV Bjoraker, GL Jennings, DE McCabe, GH Romani, PN AF Sada, PV Bjoraker, GL Jennings, DE McCabe, GH Romani, PN TI Observations of CH4, C2H6, and C2H2 in the stratosphere of Jupiter SO ICARUS LA English DT Article DE Jupiter; Jupiter; atmosphere; atmospheres; structure; atmospheres; composition; infrared observations ID JOVIAN AURORAL STRATOSPHERE; GALILEO PROBE; POLAR BRIGHTENINGS; THERMAL PROFILES; RATE-CONSTANT; ATMOSPHERE; ETHANE; ACETYLENE; ABUNDANCES; PHOTOCHEMISTRY AB We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 mu m), C2H6 (12.16 mu m), and C2H2 (13.45 mu m) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9(-1.3)(+1.9) x 10(-6) for C2H6, (5 mbar pressure level), and 2.3 +/- 0.5 x 10(-8) for C2H2 (8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties. (C) 1998 academic Press. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. RP Sada, PV (reprint author), Univ Monterrey, Dept Fis & Matemat, Av I Morones Prieto 4500 Pte, Garza Garcia 62238, NL, Mexico. EM psada@ix.netcom.com RI Romani, Paul/D-2729-2012; Bjoraker, Gordon/D-5032-2012; Jennings, Donald/D-7978-2012 NR 57 TC 31 Z9 31 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1998 VL 136 IS 2 BP 192 EP 201 DI 10.1006/icar.1998.6021 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157QN UT WOS:000078073300002 PM 11878354 ER PT J AU Zahnle, K Dones, L Levison, HF AF Zahnle, K Dones, L Levison, HF TI Cratering rates on the Galilean satellites SO ICARUS LA English DT Article DE comets; impacts; craters; Ganymede; Europa; Jupiter ID SHORT-PERIOD COMETS; JUPITER-FAMILY COMETS; HALLEY-TYPE COMETS; SIZE DISTRIBUTION; SOLAR-SYSTEM; DYNAMICAL EVOLUTION; LAPLACE RESONANCE; ASTEROID BELT; KUIPER BELT; GANYMEDE AB We exploit recent theoretical advances toward the origin and orbital evolution of comets and asteroids to obtain revised estimates for cratering rates in the jovian system. We find that most, probably more than 90%, of the craters on the Galilean satellites are caused by the impact of Jupiter-family comets (JFCs). These are comets with short periods, in generally low-inclination orbits, whose dynamics are dominated by Jupiter. Nearly isotropic comets (long period and Halley-type) contribute at the 1-10% level. Trojan asteroids might also be important at the 1-10% level; if they are important, they would be especially important for smaller craters. Main belt asteroids are currently unimportant, as each 20-km crater made on Ganymede implies the disruption of a 200-km diameter parental asteroid, a destruction rate far beyond the resources of today's asteroid belt, Twenty-kilometer diameter craters are made by kilometer-size impacters; such events occur on a Galilean satellite about once in a million years. The paucity of 20-km craters on Europa indicates that its surface is of order 10 Ma. Lightly cratered surfaces on Ganymede are nominally of order 0.5-1.0 Ga. The uncertainty in these estimates is about a factor of five. Callisto is old, probably more than 4 Ga. It is too heavily cratered to be accounted for by the current flux of JFCs. The lack of pronounced apex-antapex asymmetries on Ganymede may be compatible with crater equilibrium, but it is more easily understood as evidence for nonsynchronous rotation of an icy carapace. (C) 1998 Academic Press. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SW Res Inst, Boulder, CO 80302 USA. RP Zahnle, K (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM kzahnle@mail.arc.nasa.gov RI Levison, Harold/C-6061-2013 OI Levison, Harold/0000-0001-5847-8099 NR 82 TC 157 Z9 159 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 DEC PY 1998 VL 136 IS 2 BP 202 EP 222 DI 10.1006/icar.1998.6015 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157QN UT WOS:000078073300003 PM 11878353 ER PT J AU Buratti, BJ Mosher, JA Nicholson, PD McGhee, CA French, RG AF Buratti, BJ Mosher, JA Nicholson, PD McGhee, CA French, RG TI Near-infrared photometry of the saturnian satellites during ring plane crossing SO ICARUS LA English DT Article ID CCD OBSERVATIONS; ENCELADUS; ALBEDO; TETHYS; DIONE; SPECTROPHOTOMETRY; DYNAMICS; SYSTEM; MIMAS; TITAN AB The first near-infrared (0.9 mu m) photometric observations of Saturn's five medium-sized satellites were obtained during the August 1995 ring plane crossing with Palomar Observatory's 60-in. telescope. The albedos of the satellites are very high, indicating that a very low fraction of dark opaque contaminants is present on their icy surfaces. The geometric albedos for the leading sides of the satellites are Enceladus: 1.02; Tethys: 0.90; Dione: 0.72; and Rhea: 0.76. The geometric albedo of the trailing side of Mimas is 0.72. The amplitudes of the satellites' rotational lightcurves are somewhat less than those measured at visible wavelengths. They range from 0.40 (Dione) to 0.10 (Rhea) to 0.05 (Tethys). Both Enceladus and Mimas are brighter on the trailing side, unlike the other three satellites. These results suggest that the optical properties of all five satellites are determined by interactions with Saturn's E-ring. (C) 1998 Academic Press. C1 CALTECH, Palomar Observ, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Cornell Univ, Palomar Observ, Ithaca, NY 14853 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Wellesley Coll, Dept Astron, Wellesley, MA 02181 USA. RP Buratti, BJ (reprint author), CALTECH, Palomar Observ, 4800 Oak Grove Dr,Mail Code 183-501, Pasadena, CA 91109 USA. NR 32 TC 31 Z9 31 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1998 VL 136 IS 2 BP 223 EP 231 DI 10.1006/icar.1998.6026 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157QN UT WOS:000078073300004 ER PT J AU Baker, RD Schubert, G AF Baker, RD Schubert, G TI Deep convective entrainment by downdrafts in Jupiter's atmosphere SO ICARUS LA English DT Article DE Jupiter; Jupiter; atmosphere; atmospheres; dynamics; Galileo ID GALILEO PROBE; COMPRESSIBLE CONVECTION; ABUNDANCE; DYNAMICS; WATER; GAS AB The Galileo probe into Jupiter's atmosphere entered a "hot spot" composed of dry, less dense air. Despite assertions that hot spots are regions of downwelling, no viable mechanism has been proposed to transport less dense air over a scale height into the deep atmosphere. Here, we present a numerical simulation of convection in Jupiter's atmosphere which indicates that less dense air from above the clouds may be carried into the deep atmosphere by strong convective entrainment, (C) 1998 Academic Press. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Baker, RD (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Mesoscale Atmospher Proc Branch, Code 912, Greenbelt, MD 20771 USA. NR 30 TC 10 Z9 10 U1 2 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1998 VL 136 IS 2 BP 340 EP 343 DI 10.1006/icar.1998.6016 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157QN UT WOS:000078073300011 ER PT J AU Dowling, JP AF Dowling, JP TI Parity, time-reversal and group delay for inhomogeneous dielectric slabs: Application to pulse propagation in finite, one-dimensional, photonic bandgap structures SO IEE PROCEEDINGS-OPTOELECTRONICS LA English DT Article DE dielectric structures; electromagnetic pulse propagation ID PHASE-CONJUGATE MIRROR; REFLECTION; EDGE; GAP AB The author considers the symmetries associated with the group-velocity delay of pulse transmission and reflection in a one-dimensionally inhomogeneous, planar, dielectric structure. From the principles of energy and parity conservation - as well as time-reversal symmetry - he derives the generalised Stokes reciprocity relations for such a slab. From these relations, he obtains very general equations relating the group delays and phases of the transmitted and reflected pulses. These results have important applications to pulse propagation through one-dimensional photonic bandgap structures. C1 USA, Aviat & Missile Command, MIssile Res Dev & Engn Ctr,AMSAM,RD,WS,ST, Weap Sci Directorate,Sci & Tech Off Optimal Sci, Redstone Arsenal, AL 35898 USA. RP Dowling, JP (reprint author), NASA, Jet Propuls Lab, Quantum Informat Project, Sect 395, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jonathan.p.dowling@jpl.nasa.gov RI DOWLING, JONATHAN/L-2749-2013 NR 29 TC 19 Z9 19 U1 1 U2 5 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1350-2433 J9 IEE P-OPTOELECTRON JI IEE Proc.-Optoelectron. PD DEC PY 1998 VL 145 IS 6 BP 420 EP 435 DI 10.1049/ip-opt:19982473 PG 16 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 184HE UT WOS:000079604600020 ER PT J AU Shieh, W Maleki, L AF Shieh, W Maleki, L TI Phase noise of optical interference in photonic RF systems (vol 10, pg 1617, 1998) SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Correction C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shieh, W (reprint author), Lucent Technol, Opt Networking, Holmdel, NJ 07733 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD DEC PY 1998 VL 10 IS 12 BP 1799 EP 1799 DI 10.1109/LPT.1998.730509 PG 1 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 140EL UT WOS:000077074100045 ER PT J AU Imbriale, WA Esquivel, MS Manshadi, F AF Imbriale, WA Esquivel, MS Manshadi, F TI Novel solutions to low-frequency problems with geometrically designed beam-waveguide systems SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE beam waveguides; phase conjugation AB The poor low-frequency performance of geometrically designed beam-waveguide antennas is shown to be caused by the diffraction phase centers being far from the geometrical optics mirror foci, resulting in substantial spillover and defocusing loss. Two novel solutions are proposed: 1) reposition the mirrors to focus low frequencies and redesign the high frequencies to utilize the new mirror positions and 2) redesign the input feed system to provide an optimum solution for the low frequency. A novel use of the conjugate phase-matching technique is utilized to design the optimum low-frequency feed system and the new feed system has been implemented in the Jet Propulsion Laboratory (JPL) Research and Development beam-wavesguide (BWG) as part of a dual S/X-band feed system, The new S-band feed system is shown to perform significantly better than the original geometrically designed system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Imbriale, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 8 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD DEC PY 1998 VL 46 IS 12 BP 1790 EP 1796 DI 10.1109/8.743814 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 164UP UT WOS:000078482200003 ER PT J AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS TI A unified approach to the probability of error for noncoherent and differentially coherent modulations over generalized fading channels SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE multichannel reception; Nakagami fading; noncoherent and differentially coherent communications; postdetection diversity ID STATISTICAL-MODEL; RADIO PROPAGATION; CDMA SYSTEMS; PERFORMANCE; COMMUNICATION; DQPSK; PARAMETERS; BAND; DPSK AB We present a unified approach to determine the exact bit error rate (BER) of noncoherent and differentially coherent modulations with single and multichannel reception over additive white Gaussian noise and generalized fading channels. The multichannel reception results assume independent fading in the channels and are applicable to systems that employ postdetection equal gain combining. Our approach relies on an alternate form of the Marcum Q-function and leads to expressions of the BER involving a single finite-range integral which can be readily evaluated numerically. Aside from unifying the past results, the new approach also allows for a more general solution to the problem in that it includes many situations that in the past defied a simple solution, The best example of this occurs for multichannel reception where the fading on each channel need not be identically distributed nor even distributed according to the same family of distributions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Elect Engn, Commun Grp, Pasadena, CA 91125 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 64 TC 116 Z9 118 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD DEC PY 1998 VL 46 IS 12 BP 1625 EP 1638 DI 10.1109/26.737401 PG 14 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 152EU UT WOS:000077763900014 ER PT J AU Mehdi, I Marazita, SM Humphrey, DA Lee, TH Dengler, RJ Oswald, JE Pease, AJ Martin, SC Bishop, WL Crowe, TW Siegel, PH AF Mehdi, I Marazita, SM Humphrey, DA Lee, TH Dengler, RJ Oswald, JE Pease, AJ Martin, SC Bishop, WL Crowe, TW Siegel, PH TI Improved 240-GHz subharmonically pumped planar Schottky diode mixers for space-borne applications SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE millimeter-wave receivers; mixer noise; mixers; Schottky diode mixers ID WAVE-GUIDE MIXERS; PERFORMANCE; GHZ AB Low-noise broad intermediate frequency (IF) band 240-GHz subharmonically pumped planar Schottky diode mixers for space-borne radiometers have been developed and characterized, The planar GaAs Schottky diodes are fully integrated with the RF/IF filter circuitry via the quartz-substrate upside-down integrated device (QUID) process resulting in a robust and easily handled package, ii best double-sideband-mixer noise temperature of 490 K was achieved with 3 mW of local-oscillator power at 2-GHz IF. Over an IF band of 1.5-10 GHz, the noise temperature is below 1000 K, This state-of-the-art performance is attributed to lower parasitic capacitance devices and a low-loss waveguide circuit, Device fabrication technology and the resulting RF mixer performance obtained in the 200-250-GHz frequency range will be described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Virginia, Semicond Device Lab, Charlottesville, VA 22903 USA. RP Mehdi, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 15 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD DEC PY 1998 VL 46 IS 12 BP 2036 EP 2042 DI 10.1109/22.739280 PN 1 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 158CP UT WOS:000078098700008 ER PT J AU Boric-Lubecke, O Denning, RF Janssen, MA Frerking, MA AF Boric-Lubecke, O Denning, RF Janssen, MA Frerking, MA TI Miniature low-power submillimeter-wave spectrometer for remote sensing in the solar system SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE Gunn device oscillators; planetary atmospheres; remote sensing; submillimeter-wave frequency conversion; submillimeter-wave mixers; submillimeter-wave oscillators; submillimeter-wave radiometry; submillimeter-wave spectroscopy; temperature; temperature control AB Mass and power for the next generation of NASA's heterodyne spectrometers must be greatly reduced to satisfy the constraints of future small-spacecraft missions. In this paper, we present a new receiver concept for remote sensing in the solar system, with greatly reduced mass, power, and size compared to instruments implemented in current missions. This spectrometer was originally proposed for operation in the vicinity of the 557-GHz emission from the H2O ground-state transition. With the 557-GHz mixer and associated multiplier chain still under development, we prototyped a 220-GHz version of the instrument to verify the receiver concept, and experimentally demonstrated its functionality. The 220-GHz prototype Schottky-diode receiver requires less than 4.8 W, and has a mass of less than 1.1 kg-more than a factor of ten in mass and power reduction compared to current instruments, This significant savings, achieved through minimizing the number of receiver components, does not compromise the functionality necessary, e,g,, for a surface-based Mars atmospheric sounding instrument. For the 557-GHz version, we anticipate that the total mass would be about the same as that of the millimeter-wave prototype, while required power would be reduced by about 1.5 W with the use of InP MMIC amplifiers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boric-Lubecke, O (reprint author), RIKEN, Inst Phys & Chem Res, Photodynam Res Ctr, Sendai, Miyagi 980, Japan. EM olga@postman.riken.go.jp NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD DEC PY 1998 VL 46 IS 12 BP 2061 EP 2067 DI 10.1109/22.739283 PN 1 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 158CP UT WOS:000078098700011 ER PT J AU Lubecke, VM McGrath, WR Stimson, PA Rutledge, DB AF Lubecke, VM McGrath, WR Stimson, PA Rutledge, DB TI Micromechanical tuning elements in a 620-GHz monolithic integrated circuit SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE micromachining; submillimeter waves; tuners ID COPLANAR TRANSMISSION-LINES; SUBMILLIMETER; DISPERSION; ASTRONOMY; PARABOLA AB While monolithic integrated-circuit technology promises a practical means for realizing reliable reproducible planar millimeter and submillimeter-wave circuits, conventional planar circuits do not allow for critical post-fabrication optimization of performance. A 620-GHz quasi-optical monolithic detector circuit is used here to demonstrate the performance of two integrated micromechanical planar tuning elements. This is the first reported demonstration of integrated micromechanical tuning at submillimeter wavelengths. The tuning elements, called sliding planar backshorts (SPB's), are used to adjust the electrical length of planar transmission-line tuning stubs to vary the power delivered between a substrate-lens coupled planar antenna and a thin-film bismuth detector over a range of nearly 15 dB, The circuit performance agrees with theoretical calculations and microwave measurements of a -0.06-dB reflection coefficient made for a scale model of the integrated tuners. The demonstrated tuning range for the SPB tuners indicates that they can be valuable for characterizing components in developmental circuits and for optimizing the in-use performance of various millimeter and submillimeter-wave integrated circuits. C1 CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91125 USA. RP Lubecke, VM (reprint author), RIKEN, Inst Phys & Chem Res, Photodynam Res Ctr, Sendai, Miyagi 980, Japan. NR 30 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD DEC PY 1998 VL 46 IS 12 BP 2098 EP 2103 DI 10.1109/22.739288 PN 1 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 158CP UT WOS:000078098700016 ER PT J AU Coss, JR AF Coss, JR TI Donald K. Nichols - In memoriam SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Biographical-Item C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Coss, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1998 VL 45 IS 6 BP 2337 EP 2337 PN 1 PG 1 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 149UM UT WOS:000077624200004 ER EF