FN Thomson Reuters Web of Science™ VR 1.0 PT J AU JOSHI, RP PATHAK, S MCADOO, JA AF JOSHI, RP PATHAK, S MCADOO, JA TI HOT-ELECTRON AND THERMAL EFFECTS ON THE DYNAMIC CHARACTERISTICS OF SINGLE-TRANSIT SIC IMPACT-IONIZATION AVALANCHE TRANSIT-TIME DIODES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAAS QUANTUM WELLS; MONTE-CARLO; SILICON-CARBIDE; BULK SEMICONDUCTORS; DEVICES; SCATTERING; MICROWAVE; TRANSPORT AB We report our simulation results for the dynamic characteristics of single-transit SiC SiC impact-ionization avalanche transit-time (IMPATT) diodes. An iterative Monte Carlo-Crank-Nicholson technique has been used to solve the coupled electron transport-heat conduction problem. This procedure allows for accurate computation of both the device current as a function of temperature, time, and position, and the internal heat generation. The technique is quite general, has not been used before, and can be applied for the analysis of any power device. Our results show that the internal power generation profile within the SiC IMPATT device can have a very nonuniform axial distribution, The internal heating is seen to significantly degrade the device efficiency and optimum operating frequency. With thermal effects the output current values are lower and the transit time is increased. (C) 1995 American Institute of Physics. C1 NASA,LANGLEY RES CTR,DIV AEROSP ELECTR SYST,ELECTROOPT BRANCH,HAMPTON,VA 23681. RP JOSHI, RP (reprint author), OLD DOMINION UNIV,DEPT ELECT & COMP ENGN,NORFOLK,VA 23529, USA. NR 33 TC 8 Z9 8 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 1 PY 1995 VL 78 IS 5 BP 3492 EP 3497 DI 10.1063/1.359982 PG 6 WC Physics, Applied SC Physics GA RR845 UT WOS:A1995RR84500094 ER PT J AU STEPHENS, EF VANDIVER, R TIN, P KOKTA, MR AF STEPHENS, EF VANDIVER, R TIN, P KOKTA, MR TI CONTINUOUS-WAVE OPERATION AND TUNING CHARACTERISTICS OF ND-LUALO3 AT 1083 NM FOR HE-3 AND HE-4 OPTICAL-PUMPING SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID LASER AB cw laser operation has been achieved from a diode-pumped Nd:LuAlO3 crystal for the first time. The tuning characteristics centered about 1083 nm are presented and the laser's use for He-3 and He-4 optical pumping are established. With 1.5 W of output at 1083 nm and a slope efficiency greater than 22%, this crystal represents the first viable alternative to Nd:LMA. (C) 1995 American Institute of Physics. C1 NASA,LEWIS RES CTR,PROC SCI & TECHNOL BRANCH,CLEVELAND,OH 44135. UNION CARBIDE CORP,DIV CRYSTAL PROD 750,WASHOUGAL,WA 98671. RP STEPHENS, EF (reprint author), UNIV MISSOURI,DEPT PHYS,ROLLA,MO 65401, USA. NR 5 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 1 PY 1995 VL 78 IS 5 BP 3543 EP 3545 DI 10.1063/1.359929 PG 3 WC Physics, Applied SC Physics GA RR845 UT WOS:A1995RR84500108 ER PT J AU THY, P SEGOBYE, AK MING, DW AF THY, P SEGOBYE, AK MING, DW TI IMPLICATIONS OF PREHISTORIC GLASSY BIOMASS SLAG FROM EAST-CENTRAL BOTSWANA SO JOURNAL OF ARCHAEOLOGICAL SCIENCE LA English DT Article DE IRON AGE SETTLEMENTS; MIDDEN SOIL; BIOMASS SLAG; BOTSWANA ID FUSION; COAL; ASH; TEMPERATURE; COMBUSTION; PREDICTION; MAGMAS AB Glassy biomass slag occurs in midden piles of prehistoric settlements of east-central Botswana. The slag forms decimetre thick concordant layers in stratified ashy soil, and lacks associations with domestic ceramic and iron melting activities. Petrographic evaluation of the slag suggests maximum temperatures in the order of 1155-1290 degrees C during burning of the midden. These values exceed reasonable estimates for combustion temperature of plant remnants and cattle manure in open fire. It is suggested, as alternatives, that the glassy slag formed either from surface melting caused by strokes of lightning in an accumulation of partially decomposed organic soil, or from subsurface combustion of organic soil strata ignited by grass fires. Glassy biomass slag of prehistoric settlements, therefore, may not result from human activities, such as intentional burning of excess midden piles, and may not be contemporaneous with human occupation of the sites. (C) 1995 Academic Press Limited C1 UNIV BOTSWANA & SWAZILAND,DEPT GEOL,GABORONE,BOTSWANA. UNIV BOTSWANA & SWAZILAND,DEPT HIST,ARCHAEOL UNIT,GABORONE,BOTSWANA. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 60 TC 16 Z9 16 U1 0 U2 1 PU ACADEMIC PRESS (LONDON) LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0305-4403 J9 J ARCHAEOL SCI JI J. Archaeol. Sci. PD SEP PY 1995 VL 22 IS 5 BP 629 EP 637 DI 10.1016/S0305-4403(95)80148-0 PG 9 WC Anthropology; Archaeology; Geosciences, Multidisciplinary SC Anthropology; Archaeology; Geology GA RX419 UT WOS:A1995RX41900005 ER PT J AU WATENPAUGH, DE VISSING, SF LANE, LD BUCKEY, JC FIRTH, BG ERDMAN, W HARGENS, AR BLOMQVIST, CG AF WATENPAUGH, DE VISSING, SF LANE, LD BUCKEY, JC FIRTH, BG ERDMAN, W HARGENS, AR BLOMQVIST, CG TI PHARMACOLOGICAL ATRIAL-NATRIURETIC-PEPTIDE REDUCES HUMAN LEG CAPILLARY FILTRATION SO JOURNAL OF CARDIOVASCULAR PHARMACOLOGY LA English DT Article DE EXTRACELLULAR FLUID; HEMOCONCENTRATION; CAPILLARY PERMEABILITY; CAPILLARY PRESSURE ID PLASMA-LEVELS; RESPONSES; PERMEABILITY; HEMATOCRIT; INCREASES; FOREARM; VOLUME; RATS AB Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethysmography of supine healthy male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n = 6) and during placebo infusion (n = 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma [ANP] from 30 +/- 4 to 2,568 +/- 595 pmol/L. Systemic hemoconcentration occurred during ANP infusion: mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3%, respectively, relative to preinfusion baseline values (p < 0.05). Mean calf filtration, however, was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20% with ANP infusion, whereas blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, pharmacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchnic sites or both, while having the opposite effect in the leg. C1 UNIV TEXAS,SW MED CTR,DALLAS,TX. RP WATENPAUGH, DE (reprint author), NASA,AMES RES CTR,DIV LIFE SCI,GRAVITAT RES BRANCH 239 11,MOFFETT FIELD,CA 94035, USA. NR 34 TC 5 Z9 5 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0160-2446 J9 J CARDIOVASC PHARM JI J. Cardiovasc. Pharmacol. PD SEP PY 1995 VL 26 IS 3 BP 414 EP 419 DI 10.1097/00005344-199509000-00011 PG 6 WC Cardiac & Cardiovascular Systems; Pharmacology & Pharmacy SC Cardiovascular System & Cardiology; Pharmacology & Pharmacy GA RT456 UT WOS:A1995RT45600011 PM 8583783 ER PT J AU NOEVER, DA AF NOEVER, DA TI ORDER AND STATISTICAL CRYSTALLOGRAPHY OF PATTERNED BREATH FIGURES SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article ID CELLS AB Patterned condensation or breath figures form from the dropwise condensation of water on a surface. Such networks have attracted recent attention as environmental sensors, optical diffraction gratings, and tools for studying thin film behavior. To test a random breath figure's regularity in shape and size, the formalism of statistical crystallography is developed here for drop sidedness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter, and nearest neighbor shapes. Taken together, these physicochemical laws predict a highly non-equilibrium structure for the breath figure which evolves as a unimodal shape distribution without dominant drop perimeter energy. (C) 1995 Academic Press,Inc. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES-76,HUNTSVILLE,AL 35812, USA. NR 14 TC 2 Z9 2 U1 1 U2 8 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD SEP 1 PY 1995 VL 174 IS 1 BP 92 EP 96 DI 10.1006/jcis.1995.1368 PG 5 WC Chemistry, Physical SC Chemistry GA RQ708 UT WOS:A1995RQ70800012 ER PT J AU WHANG, YC BURLAGA, LF NESS, NF AF WHANG, YC BURLAGA, LF NESS, NF TI LOCATIONS OF THE TERMINATION SHOCK AND THE HELIOPAUSE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND INTERACTION; INTERSTELLAR-MEDIUM; OUTER HELIOSPHERE; COSMIC-RAYS; HYDROGEN; MODEL; DISTANCE; EMISSION AB The locations of the termination shock and the heliopause are restudied by taking into account the effects of pickup protons. The study uses available plasma and magnetic field data from Voyagers over a 14-year period (1978-1991) and Voyager observations of the 1992-1993 radio emission event. Outside 30 AU, pickup protons have a significant influence on dynamical structures of the outer heliosphere. The solar wind is treated as a mixture of electrons, solar wind protons, and interstellar pickup protons. If the magnitude of the interstellar magnetic field B-int is given, one can quantitatively study the motion and location of the termination shock. We find that the location is anticorrelated with the sunspot number. The absolute mean of the shock speed is 19 km/s, and the quadratic mean of the shock speed is 24 km/s. Because B-int is poorly known, additional information is needed in studying the termination shock. Cummings et al, (1994) have used observations of anomalous cosmic rays to estimate the location of the shock. The observations of the 1991 global merged interaction region (GMIR) and GMIR shock and the 1992-1993 radio emission event provide another handle for the study of the termination shock and the heliopause. After its penetration through the termination shock, the GMIR shock continued to propagate in the subsonic region of the solar wind and eventually interacted with the heliopause. This interaction produced a transmitted shock propagating outward in the inter-stellar medium and a reflected shock propagating inward toward the Sun in the subsonic solar wind. The plasma frequencies behind the reflected and the transmitted shocks can be responsible for the 2- and 3-kHz radio emissions, respectively. We assume that the impingement of the GMIR shock at the heliopause occurred at the time when Voyagers started receiving the radio emissions. Taking into account the effects of pickup protons, we find that the locations of the termination shock and the heliopause in 1991-1992 are at approximately 66 AU and 150 AU, respectively. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP WHANG, YC (reprint author), CATHOLIC UNIV AMER,DEPT MECH ENGN,WASHINGTON,DC 20064, USA. NR 41 TC 54 Z9 54 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17015 EP 17023 DI 10.1029/95JA01106 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300003 ER PT J AU AGIM, YZ VINAS, AF GOLDSTEIN, ML AF AGIM, YZ VINAS, AF GOLDSTEIN, ML TI MAGNETOHYDRODYNAMIC AND HYBRID SIMULATIONS OF BROAD-BAND FLUCTUATIONS NEAR INTERPLANETARY SHOCKS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID POLARIZED ALFVEN WAVES; QUASI-PARALLEL SHOCKS; PROPAGATING HYDROMAGNETIC-WAVES; ION-BEAM INSTABILITIES; URANIAN BOW SHOCK; PARAMETRIC-INSTABILITIES; MODULATIONAL INSTABILITY; FINITE-AMPLITUDE; SOLAR-WIND; UPSTREAM WAVES AB We present results of a theoretical study of evolution of a spectrum of finite amplitude right-hand elliptically polarized magnetohydrodynamic (MHD) waves. The analysis includes use of one-and-a-half-dimensionel solutions of the equations that describe compressible MHD together with one-and-a-half-dimensional hybrid simulation of the phenomenon. The motivation of the study is to understand the origin and properties of finite amplitude waves often observed-in the vicinity of collisionless shocks in the heliosphere. The solutions of the MHD equations are compared with both the results of the hybrid simulations and observations previously reported by Vinas et al. (1984) in the vicinity of a quasi-parallel interplanetary shock. The initial conditions of the MHD solutions were constructed to model the observed spectrum of magnetic and velocity fluctuations; plasma parameters were also chosen to replicate the observed parameters. For the typical parameters of beta = 0.5, delta B/B-0 = 0.25 and a spectrum of parallel propagating, circularly polarized dispersive waves, initially the density and magnetic energy density correlations grow due to the (nonlinear) ponderomotive effect. The spectral features below the ion cyclotron frequency are established quickly on the Alfvenic timescale but then persist and match closely the observed fluctuations. The parametric decay instabilities that subsequently appear further enhance the density fluctuations and produce a high-frequency magnetic power spectrum consistent with the spacecraft observation. The MHD and hybrid simulations extend the previous picture of wave generation by a beam-driven ion cyclotron instability to the fully nonlinear stage. RP AGIM, YZ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,COD 692,GREENBELT,MD 20771, USA. RI Goldstein, Melvyn/B-1724-2008 NR 65 TC 18 Z9 18 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17081 EP 17106 DI 10.1029/95JA00527 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300010 ER PT J AU ROBERTS, DA AF ROBERTS, DA TI ON 2-COMPONENT MODELS OF SOLAR-WIND FLUCTUATIONS - COMMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID ALFVEN WAVES RP ROBERTS, DA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. RI Roberts, Dana/D-4625-2012 NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17135 EP 17135 DI 10.1029/95JA01025 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300014 ER PT J AU DELCOURT, DC SAUVAUD, JA MARTIN, RF MOORE, TE AF DELCOURT, DC SAUVAUD, JA MARTIN, RF MOORE, TE TI GYROPHASE EFFECTS IN THE CENTRIFUGAL IMPULSE MODEL OF PARTICLE MOTION IN THE MAGNETOTAIL SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD; PLASMA SHEET; NONLINEAR DYNAMICS; CHARGED-PARTICLES; MAGNETOSPHERE; DIFFUSION; BOUNDARY; ORBITS; CHAOS; TAIL AB We investigate the dynamics of charged particles in a magnetic field reversal in the particular case where the Larmor radius is comparable to the magnetic field line curvature radius. In the current interpretation framework based upon the parameter K (defined as the square root of the minimum curvature radius-to-maximum Larmor radius ratio), this situation corresponds to K of the order of 1. We show that this nonadiabatic regime, which lies at the transition between adiabatic motion (K >> 1) and the nonadiabatic one characterized by oscillations about the field minimum (K < 1), results from prominent centrifugal effects in the field reversal. To model these effects, we develop a simple analytical description which is based upon an impulsive centrifugal force perturbing the particle gyromotion on the time scale of the cyclotron turn. Comparisons with numerical calculations of ion trajectories demonstrate that this centrifugal impulse model adequately describes both the magnetic moment variations and the gyrophase variations experienced by the particles. As for the magnetic moment, three distinct behaviors (negligible change, strong phase dependence with possible damping, and systematic enhancement) are identified depending upon pitch angle. As for the gyration phase, important bunching effects are obtained which are interpreted as being due to the action of the impulsive centrifugal force. These phase bunching effects are enhanced as the K parameter approaches unity. In the limit K similar to 1, a strong imbalance is obtained between the two phase sectors corresponding to duskward and dawnward motions. This imbalance, which extends over a few tenths of an Earth radius in the Z direction, leads to the formation of a thin current sheet in the vicinity of the magnetotail midplane. C1 ILLINOIS STATE UNIV,DEPT PHYS,NORMAL,IL 61761. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. CTR ETUD SPATIALE RAYONNEMENTS,CNRS,F-31029 TOULOUSE,FRANCE. RP DELCOURT, DC (reprint author), CTR ETUD ENVIRONNEMENTS TERRESTRE & PLANETAIRES,4 AVE NEPTUNE,F-94107 ST MAUR FOSSES,FRANCE. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 26 TC 12 Z9 12 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17211 EP 17220 DI 10.1029/95JA00657 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300025 ER PT J AU BERNHARDT, PA SIEFRING, CL RODRIQUEZ, P HAAS, DG BAUMBACK, MM ROMERO, HA SOLIN, DA DJUTH, FT DUNCAN, LM HUNTON, DE POLLOCK, CJ SULZER, MP TEPLEY, CA WAGNER, LS GOLDSTEIN, JA AF BERNHARDT, PA SIEFRING, CL RODRIQUEZ, P HAAS, DG BAUMBACK, MM ROMERO, HA SOLIN, DA DJUTH, FT DUNCAN, LM HUNTON, DE POLLOCK, CJ SULZER, MP TEPLEY, CA WAGNER, LS GOLDSTEIN, JA TI THE IONOSPHERIC FOCUSED HEATING EXPERIMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID POWER RADIO-WAVES; ARTIFICIAL AIRGLOW; FREQUENCY; ARECIBO AB The Ionospheric Focused Heating rocket was launched on May 30, 1992. The sounding rocket carried an instrument and chemical payload along a trajectory that crossed the intersection of the beams from the 430-MHz incoherent scatter radar and the 5.1-MHz high-power radio wave facility near Arecibo. The release of 30 kg of CF3Br into the F region at 285 km altitude produced an ionospheric hole that acted like a convergent lens to focus the HF transmissions. The power density inside the radio beam was raised by 12 dB immediately after the release. A wide range of new processes were recorded by in situ and ground-based instruments. Measurements by instruments flying through the modified ionosphere show small-scale microcavities (<1 m) and downshifted electron plasma (Langmuir) waves inside the artificial cavity, electron density spikes at the edge of the cavity, and Langmuir waves coincident with ion gyroradius (4 m) cavities near the radio wave reflection altitude. The Arecibo incoherent scatter radar showed 20 dB or greater enhancements in ion acoustic and Langmuir wave turbulence after the 5.1-MHz radio beam was focused by the artificial lens. Enhancements in airglow from chemical reactions and, possibly, electron acceleration were recorded with optical instruments. The Ionospheric Focused Heating experiment verified some of the preflight predictions and demonstrated the value of active experiments that combine high-power radio waves with chemical releases. C1 GEOSPACE RES INC,EL SEGUNDO,CA. UNIV TULSA,SCH ENGN & APPL SCI,TULSA,OK 74104. GPID,PHILLIPS LAB,BEDFORD,MA. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NATL ASTRON & IONOSPHERE CTR,ARECIBO OBSERV,ARECIBO,PR 00613. USN,RES LAB,DIV INFORMAT TECHNOL,WASHINGTON,DC 20375. RP BERNHARDT, PA (reprint author), USN,RES LAB,DIV PLASMA PHYS,CODE 6794,4555 OVERLOOK RD,WASHINGTON,DC 20375, USA. NR 29 TC 22 Z9 22 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17331 EP 17345 DI 10.1029/94JA01887 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300036 ER PT J AU TORR, MR TORR, DG CHANG, T RICHARDS, P SWIFT, W LI, N AF TORR, MR TORR, DG CHANG, T RICHARDS, P SWIFT, W LI, N TI THERMOSPHERIC NITRIC-OXIDE FROM THE ATLAS-1 AND SPACELAB-1 MISSIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Review ID ELECTRON-IMPACT EXCITATION; REACTION-RATE COEFFICIENTS; CROSS-SECTIONS; ATOMIC OXYGEN; ROCKET MEASUREMENTS; SOLAR CYCLE-21; GAMMA-BAND; DISSOCIATIVE RECOMBINATION; TEMPERATURE-DEPENDENCE; IONIZATION FREQUENCIES AB Spectral and spatial images obtained with the Imaging Spectrometric Observatory on the ATLAS 1 and Spacelab 1 missions are used to study the ultraviolet emissions of nitric oxide in the thermosphere. By synthetically fitting the measured NO gamma bands, intensities are derived as a function of altitude and latitude. We find that the NO concentrations inferred from the ATLAS 1 measurements are higher than predicted by our thermospheric airglow model and tend to lie to the high side of a number of earlier measurements. By comparison with synthetic spectral fits, the shape of the NO gamma bands is used to derive temperature as a function of altitude. Using the simultaneous spectral and spatial imaging capability of the instrument, we present the first simultaneously acquired altitude images of NP gamma band temperature and intensity in the thermosphere. The lower thermospheric temperature images show structure as a function of altitude. The spatial imaging technique appears to be a viable means of obtaining temperatures in the middle and lower thermosphere, provided that good information is also obtained at the higher altitudes, as the contribution of the overlying, hotter NO is nonnegligible. By fitting both self-absorbed and nonabsorbed bands of the NO gamma system, we show that the self absorption effects are observable up to 200 km, although small above 150 km. The spectral resolution of the instrument (1.6 Angstrom) allows separation of the N+(S-5) doublet, and we show the contribution of this feature to the combination of the NO gamma (1,0) band and the N+(S-5) doublet as a function of altitude (less than 10% below 200 km). Spectral images including the NO delta bands support previous findings that the fluorescence efficiency is much higher than that determined from laboratory measurements, The Spacelab 1 data indicate the presence of a significant population of hot NO in the vehicle environment of that early shuttle mission. C1 UNIV ALABAMA,OPT AERON LAB,HUNTSVILLE,AL 35899. RP TORR, MR (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PAYLOAD PROJECT OFF,HUNTSVILLE,AL 35812, USA. NR 109 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17389 EP 17413 DI 10.1029/95JA01040 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300040 ER PT J AU SHEPHERD, MG MCCONNELL, JC TOBISKA, WK GLADSTONE, GR CHAKRABARTI, S SCHMIDTKE, G AF SHEPHERD, MG MCCONNELL, JC TOBISKA, WK GLADSTONE, GR CHAKRABARTI, S SCHMIDTKE, G TI INFERENCE OF ATOMIC OXYGEN CONCENTRATION FROM REMOTE-SENSING OF OPTICAL AURORA SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-IMPACT EXCITATION; ENERGY BUDGET CAMPAIGN; B RED AURORA; CROSS-SECTIONS; LOWER THERMOSPHERE; SATELLITE MEASUREMENTS; HIGH-LATITUDE; DISSOCIATIVE RECOMBINATION; ROCKET MEASUREMENTS; NEUTRAL ATMOSPHERE AB A remote sensing method has been developed for the determination of the [O]/[O-MSIS] ratio in aurora, using ratios of the O I (557.7 nm) and N-2(+) (391.4 nm) emissions, It is shown that the method can be used for the analysis of measurements integrated along the line of sight, provided data only above the emission rate peak are used. The method is applied to the case of horizontal viewing from a vertically oriented rocket so that a large volume of space was sampled around the rocket, The method can potentially be applied to satellite limb images, provided some independent information about the location of the aurora is available, as it was for the rocket observations, Photometric measurements of the N-2(+) (391.4 nm) and O I (557.7 nm) emissions obtained during the Energy Budget Campaign 1980 on flight E-2 with the instrument EF11 and its reflight in 1981 were used in the analysis presented, During the first flight the rocket horizontally viewed two distinct aurorae, a nearby diffuse patch, and a more distant pulsating aurora, Results obtained by the same EF11 instrument on a second flight through an auroral are in 1981 are also presented, Two types of atomic oxygen variability were found in both of the flights. In the first type, [O] is increased above [O-MSIS] by a factor of 1.5 at 180 km, is equal to the MSIS model at 160 km, and is less than MSIS below that; that is, the scale height of [O] was increased. The experimental I(557.7)/I(391.4) ratio was constant with altitude, In the second type, the [O] was depleted by about a factor of 2 over the altitude range of 120-180 km, while the 1(557.7)/I(391.4) ratio decreased with altitude. The inferred atomic oxygen concentrations of 0.5 to 2 with respect to MSIS suggested different vertical flows on the two cases, Independent evidence is provided by atmospheric composition measurements made during the same campaign. C1 NATL RES COUNCIL CANADA, HERZBERG INST ASTROPHYS, OTTAWA, ON K1A 0R6, CANADA. TELOS, JET PROPULS LAB, PASADENA, CA USA. SW RES INST, SAN ANTONIO, TX USA. BOSTON UNIV, CTR SPACE PHYS, BOSTON, MA 02215 USA. INST PHYS MESSTECH, W-7800 FREIBURG, GERMANY. RP SHEPHERD, MG (reprint author), YORK UNIV, CTR RES EARTH & SPACE SCI, 4700 KEELE ST, TORONTO, ON M3J 1P3, CANADA. NR 63 TC 6 Z9 6 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17415 EP 17428 DI 10.1029/94JA03374 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300041 ER PT J AU MAYNARD, NC AGGSON, TL HERRERO, FA LIEBRECHT, MC SABA, JL AF MAYNARD, NC AGGSON, TL HERRERO, FA LIEBRECHT, MC SABA, JL TI AVERAGE EQUATORIAL ZONAL AND VERTICAL ION DRIFTS DETERMINED FROM SAN-MARCO D-ELECTRIC-FIELD MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID F-REGION; PLASMA DRIFTS; DYNAMICS EXPLORER-2; WINDS; THERMOSPHERE; IONOSPHERE; JICAMARCA; MODEL; DE-2 AB San Marco D electric field measurements have been averaged in-terms of their equivalent ion drift to produce an average pattern of equatorial zonal and vertical ion drifts. Variations with season, solar activity, Kp, lunar phase and longitude have been analyzed. Similarities and some differences from previous Jicamarca, DE 2 and AE-E results are seen. Confirmation is given of the dominance of the F region dynamo in the 1900-2100 local time region. The daytime zonal ion drift is larger for high F10.7 values than that for low values. There is little variation between high and low values of Kp. Superrotation is evident in this data set and is larger at equinox compared to solstice. At the June solstice there are significant differences between the average ion drifts in the longitude sector where the geomagnetic equator is north of the geographic equator (Indian sector) and the sector where the geomagnetic equator is south of the geographic equator (Peruvian sector). The daytime upward velocity is larger in the Indian sector than in the Peruvian sector, and it reverses later in the evening in the Indian sector. Daytime westward zonal velocities are larger and the nighttime eastward velocities are smaller in the Indian sector. A presunrise enhancement is seen in the downward velocity in the Indian sector but not in the Peruvian sector. Significant variations are also seen with the phase of the moon. In light of current theory, the lunar variations suggest a complex interaction of E and F region dynamo sources with conductivity, changing in phase and character with latitude. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. MCL SCI SOFTWARE,SILVER SPRING,MD. HUGHES STX CORP,LANHAM,MD. RP MAYNARD, NC (reprint author), MISSION RES CORP,1 TARA BLVD,SUITE 302,NASHUA,NH 03062, USA. NR 49 TC 29 Z9 29 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD SEP 1 PY 1995 VL 100 IS A9 BP 17465 EP 17479 DI 10.1029/95JA00767 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT743 UT WOS:A1995RT74300045 ER PT J AU KELKAR, AG JOSHI, SM ALBERTS, TE AF KELKAR, AG JOSHI, SM ALBERTS, TE TI DISSIPATIVE CONTROLLERS FOR NONLINEAR MULTIBODY FLEXIBLE SPACE SYSTEMS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID POSITIVITY AB The problem of controlling a class of nonlinear multibody flexible space systems is considered. The system configuration consists of a flexible central body to which a number of flexible articulated appendages are attached, resulting in highly nonlinear dynamics. Assuming collocated actuators and sensors, global asymptotic stability of such systems is established using a nonlinear passivity-based control law. In addition, a special case where the central-body motion is small while the appendages can undergo unlimited motion, it is shown that the system, although highly nonlinear, can be stabilized by linear static and dynamic dissipative control laws. Furthermore, the static dissipative control law preserves stability despite actuator and sensor nonlinearities of certain types. In all cases, the stability does not depend on the knowledge of the model and hence is robust to modeling errors and uncertainties. The results are applicable to a broad class of systems, such as flexible multilink manipulators and multipayload space platforms. The stability proofs use the Lyapunov approach and exploit the inherent passivity of such systems. C1 OLD DOMINION UNIV,DEPT AEROSP ENGN,NORFOLK,VA 23529. RP KELKAR, AG (reprint author), NASA,LANGLEY RES CTR,DIV FLIGHT DYNAM & CONTROL,HAMPTON,VA 23665, USA. NR 16 TC 11 Z9 14 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD SEP-OCT PY 1995 VL 18 IS 5 BP 1044 EP 1052 DI 10.2514/3.21503 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RZ381 UT WOS:A1995RZ38100016 ER PT J AU SU, TJ BABUSKA, V CRAIG, RR AF SU, TJ BABUSKA, V CRAIG, RR TI SUBSTRUCTURE-BASED CONTROLLER-DESIGN METHOD FOR FLEXIBLE STRUCTURES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID OVERLAPPING INFORMATION SETS AB In this paper, a decentralized procedure for designing controllers for flexible structures is presented, With decentralized control design methods, the system to be controlled is divided into subsystems for which controllers are designed, These are then combined in some way to form a controller applicable to the original system, In the proposed method, the structure to be controlled is considered as a collection of substructures. For each substructure, a subcontroller is designed with linear quadratic optimal control theory, although any method can be used, Then, a controller synthesis scheme called Substructural Controller Synthesis (SCS) is used to assemble the subcontrollers into a system controller, which is used to control the whole structure, The proposed method is closely related to component mode synthesis methods of structural dynamics and to decentralized control using overlapping subsystems, It is attractive because, unlike most decentralized methods, an explicit decomposition is generally not needed since substructure models often exist a priori, Also, an SCS controller is very adaptable because each subcontroller is designed based on an individual substructure model; therefore, the controller can be updated very economically if part of the structure changes, A plane truss example bused to illustrate the proposed method. C1 UNIV TEXAS,DEPT AEROSP ENGN & ENGN MECH,AUSTIN,TX 78712. RP SU, TJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23662, USA. NR 14 TC 14 Z9 16 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD SEP-OCT PY 1995 VL 18 IS 5 BP 1053 EP 1061 DI 10.2514/3.21504 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RZ381 UT WOS:A1995RZ38100017 ER PT J AU RENAUD, ML AF RENAUD, ML TI MOVEMENTS AND SUBMERGENCE PATTERNS OF KEMPS RIDLEY TURTLES (LEPIDOCHELYS KEMPII) SO JOURNAL OF HERPETOLOGY LA English DT Article ID SEA-TURTLES AB Four Kemp's ridley (Lepidochelys kempii) turtles, ranging in straight-line carapace length from 51 to 60 cm and in weight from 19 to 27 kg, were released in 12 to 19 m water depths off Florida, Texas, and North Carolina and tracked for 1.0 to 8.5 months. Movements up to 2600 km were observed. The number of submergences per day was inversely proportional to the duration of submergences per day. These ridleys spent 89% of their time submerged and frequented waters ranging in depth from 1-140 m. Turtles ranged from inshore to 77 km offshore. Mean swimming speeds of these turtles were from 0.7 to 1.3 km/h, with over 95% of the actual velocity values less than or equal to 5 km/h. RP RENAUD, ML (reprint author), SE FISHERIES CTR,NATL MARINE FISHERIES SERV,GALVESTON LAB,4700 AVE U,GALVESTON,TX 77551, USA. NR 18 TC 18 Z9 21 U1 1 U2 6 PU SOC STUD AMPHIBIANS REPTILES PI OXFORD PA DEPT OF ZOOLOGY MIAMI UNIV, OXFORD, OH 45056 SN 0022-1511 J9 J HERPETOL JI J. Herpetol. PD SEP PY 1995 VL 29 IS 3 BP 370 EP 374 DI 10.2307/1564986 PG 5 WC Zoology SC Zoology GA TA491 UT WOS:A1995TA49100006 ER PT J AU LONG, MK BACKES, PG AF LONG, MK BACKES, PG TI EXTENDED IMPEDANCE CONTROL USING REAL AND VIRTUAL SENSORS FOR REDUNDANT MANIPULATORS SO JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS LA English DT Article DE REDUNDANT MANIPULATORS; IMPEDANCE CONTROL; FORCE CONTROL; SENSOR FUSION; SUPERVISED AUTONOMY; TASK SPACE AB Control of a redundant manipulator based on an impedance-control framework with multiple simultaneous control sources is described. Each control source provides a different behavior type. An application is decomposed into multiple simultaneous behaviors whose resultant behavior will provide the motion necessary to execute the task. The simultaneous control inputs are merged using impedance control to compute a resultant command to the manipulator. The task space of each behavior can have the dimensionality of the mechanism being controlled. Control of a seven-degree-of-freedom manipulator is described here with an available task space for each behavior of dimensionality seven. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0921-0296 EI 1573-0409 J9 J INTELL ROBOT SYST JI J. Intell. Robot. Syst. PD SEP PY 1995 VL 14 IS 1 BP 89 EP 103 DI 10.1007/BF01254009 PG 15 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA RU897 UT WOS:A1995RU89700006 ER PT J AU SHEN, TC WANG, ML AF SHEN, TC WANG, ML TI A NEW METHOD FOR THE PREPARATION OF POLYMERIC POROUS LAYER OPEN-TUBULAR COLUMNS FOR GC APPLICATION SO JOURNAL OF MICROCOLUMN SEPARATIONS LA English DT Article; Proceedings Paper CT 17th International Symposium on Capillary Chromatography and Electrophoresis CY MAY, 1995 CL WINTERGREEN, VA DE POROUS LAYER OPEN TUBULAR COLUMN; POLYMERIC POROUS LAYER CAPILLARY COLUMN; IN SITU POLYMERIZATION AB A new method to prepare polymeric PLOT columns by using in situ polymerization technology is described. The method involves a straightforward in situ polymerization of the monomer. The polymer produced is directly coated on the metal tubing. This eliminates many of the steps needed in conventional polymeric PLOT column preparation. Our method is easy to operate and produces very reproducible columns, as shown previously (T. C. Shen, J. Chromatogr. Sci. 30, 239, 1992). The effects of solvents, tubing pretreatments, initiators and reaction temperatures in the preparation of PLOT columns are studied. Several columns have been developed to separate (1) highly polar compounds, such as water and ammonia or water and HCN, and (2) hydrocarbons and inert gases. A recent improvement has allowed us to produce bonded polymeric PLOT columns. These were studied, and the results are included also. (C) 1995 John Wiley & Sons, Inc. RP SHEN, TC (reprint author), NASA,AMES RES CTR,SETI INST,MOFFETT FIELD,CA 94035, USA. NR 14 TC 4 Z9 4 U1 1 U2 2 PU MICROSEPARATIONS INC PI PROVO PA DEPT CHEM BRIGHAM YOUNG UNIV, PROVO, UT 84602-1022 SN 1040-7685 J9 J MICROCOLUMN SEP JI J. Microcolumn Sep. PD SEP-OCT PY 1995 VL 7 IS 5 BP 471 EP 475 DI 10.1002/mcs.1220070506 PG 5 WC Chemistry, Analytical SC Chemistry GA TF385 UT WOS:A1995TF38500005 PM 11543387 ER PT J AU COHEN, EA MCRAE, GA TAN, TL FRIEDL, RR JOHNS, JWC NOEL, M AF COHEN, EA MCRAE, GA TAN, TL FRIEDL, RR JOHNS, JWC NOEL, M TI THE NU(1) BAND OF HOBR SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID MOLECULAR-STRUCTURE; CONSTANTS; STRENGTHS; SPECTRUM AB The nu(1) band of HOBr centered at 3614.903 cm(-1) has been observed at 0.006 cm(-1) resolution. The band is a hybrid type with \(partial derivative mu(b)/partial derivative Q(1))/(partial derivative mu(a)/partial derivative Q(l))\ approximate to 0.84. The spectra of both bromine isotopes have been simultaneously fitted with a single calculation which includes all the previously reported rotational transitions. There appear to be no strong local perturbations to complicate the fitting of the line positions. Precise parameters are reported for the upper states as well as improved parameters for the ground states of both species. There is a prominent Herman-Wallis effect for the b-type transitions, which is well described by linear and quadratic terms in K-a. The equilibrium structure has been calculated. (C) 1995 Academic Press, Inc. C1 ATOM ENERGY CANADA LTD,CHALK RIVER NUCL LABS,CHALK RIVER,ON K0J 1J0,CANADA. NATL UNIV SINGAPORE,FAC SCI,DEPT PHYS,SINGAPORE 0511,SINGAPORE. NATL RES COUNCIL CANADA,STEACIE INST MOLEC SCI,OTTAWA,ON K1A 0R6,CANADA. NATL RES COUNCIL CANADA,INST NATL MEASUREMENT STAND,OTTAWA,ON K1A 0R6,CANADA. RP COHEN, EA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 16 TC 32 Z9 35 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD SEP PY 1995 VL 173 IS 1 BP 55 EP 61 DI 10.1006/jmsp.1995.1218 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA RU652 UT WOS:A1995RU65200008 ER PT J AU KLEINER, I TARRAGO, G BROWN, LR AF KLEINER, I TARRAGO, G BROWN, LR TI POSITIONS AND INTENSITIES IN THE 3-NU(2)/NU(2)+NU(4) VIBRATIONAL SYSTEM OF (NH3)-N-14 NEAR 4 MU-M SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID INVERSION-ROTATION SPECTRA; ENERGY-LEVELS; TETRAHEDRAL MOLECULES; AMMONIA; PENTAD; CORIOLIS; POLYADS; STATES; NH3; V3 AB We report experimental line positions and intensities of the 3 nu(2) and nu(2) + nu(4) bands of (NH3)-N-14 obtained from 0.011 cm(-1) unapodized resolution spectra recorded with the Fourier transform spectrometer at Kitt Peak National Observatory, A total of 1366 lines with J' less than or equal to 13 have been assigned from which 1213 line positions with J' less than or equal to 12 are fitted. using an effective rotation-inversion Hamiltonian to achieve a rms of 0.0069 cm(-1); 726 intensity measurements are modeled to 12 terms of dipole moment expansion to +/-6%. The band strengths of 3 nu(2) (s - a) at 2384.15 cm(-1), of 3 nu(2) (a - s) at 2895.52 cm(-1), of nu(2) + nu(4) (s - s) at 2540.53 cm(-1), and of nu(2) + nu(4) (a - a) at 2586.13 cm(-1) are estimated to be 0.61(3), 0.244(7), 0.186(3) and 0.174(25) cm(-2) atm(-1), respectively, at 296 K. In addition to the 3 nu(2)/nu(2) + nu(4) system, there are a number of strong lines that are thought to belong to hot bands. A prediction of the line positions and intensities has been generated for all lines with intensities greater than 0.1 X 10(-6) cm(-2) atm(-1) at 296 K and submitted to the HITRAN database. Implications about the suitability of the Hamiltonian used are explored, given that the experimental accuracy is about 16 times better than has been achieved by the fit. (C) 1995 Academic Press, Inc. C1 UNIV PARIS 11,LAB ASSOCIE,PARIS,FRANCE. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP KLEINER, I (reprint author), UNIV PARIS 06,PHYS MOLEC & APPLICAT LAB,CNRS,UNITE PROPRE,LAB ASSOCIE,TOUR 13,4 PL JUSSIEU,F-75252 PARIS 05,FRANCE. NR 26 TC 29 Z9 29 U1 0 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD SEP PY 1995 VL 173 IS 1 BP 120 EP 145 DI 10.1006/jmsp.1995.1224 PG 26 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA RU652 UT WOS:A1995RU65200014 ER PT J AU VANDERMEULEN, MCH MOREYHOLTON, ER CARTER, DR AF VANDERMEULEN, MCH MOREYHOLTON, ER CARTER, DR TI HINDLIMB SUSPENSION DIMINISHES FEMORAL CROSS-SECTIONAL GROWTH IN THE RAT SO JOURNAL OF ORTHOPAEDIC RESEARCH LA English DT Article ID MOUSE LONG BONES; SIMULATED WEIGHTLESSNESS; STRENUOUS EXERCISE; INDUCED OSTEOPENIA; MATURING RAT; STRENGTH; SPACEFLIGHT AB Growth, functional adaptation, and torsional strength were examined in the femora of 39-day-old male Sprague-Dawley rats subjected to hindlimb suspension for 0, 1, 2, 3, or 4 weeks and were compared with measurements for age-matched control animals. Our goal was to understand the effect of reduced loading on the normal age-related changes in femoral properties during growth. The control animals exhibited growth-related increases in all geometric and torsional properties of the femur. The mean body mass and femoral length of the hindlimb-suspended rats were similar to those of the controls throughout the experiment. Over 4 weeks, the femoral cross-sectional and torsional measurements from the hindlimb-suspended rats demonstrated increases in comparison with the basal values (+33% cross-sectional area, +64% polar moment of inertia, +67% ultimate torque, and +181% torsional rigidity), but the age-matched controls showed significantly greater growth-related increases (+71% cross-sectional area, +136% polar moment of inertia, +127% ultimate torque, and +367% torsional rigidity). The differences in femoral structural strength between the hindlimb-suspended animals and the age-matched controls were attributable to differences in altered cross-sectional geometry. C1 STANFORD UNIV,DEPT MECH ENGN,BIOMECH ENGN PROGRAM,STANFORD,CA. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP VANDERMEULEN, MCH (reprint author), VET AFFAIRS MED CTR,CTR REHABIL RES & DEV 153,3801 MIRANDA AVE,PALO ALTO,CA 94304, USA. RI van der Meulen, Marjolein/D-1549-2010 OI van der Meulen, Marjolein/0000-0001-6637-9808 NR 28 TC 36 Z9 37 U1 0 U2 1 PU JOURNAL BONE JOINT SURGERY INC PI NEEDHAM PA 20 PICKERING ST, NEEDHAM, MA 02192 SN 0736-0266 J9 J ORTHOPAED RES JI J. Orthop. Res. PD SEP PY 1995 VL 13 IS 5 BP 700 EP 707 DI 10.1002/jor.1100130509 PG 8 WC Orthopedics SC Orthopedics GA TH315 UT WOS:A1995TH31500008 PM 7472748 ER PT J AU BAIN, DB SMITH, CE HOLDEMAN, JD AF BAIN, DB SMITH, CE HOLDEMAN, JD TI MIXING ANALYSIS OF AXIALLY OPPOSED ROWS OF JETS INJECTED INTO CONFINED CROSS-FLOW SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A CFD parametric study was performed to analyze axially opposed rows of jets mixing with crossflow in a rectangular duct. Isothermal analysis was conducted to determine the influence of lateral geometric arrangement on mixing. Two lateral arrangements were analyzed: 1) inline (jets' centerlines aligned with each other on top and bottom walls) and 2) staggered (jets' centerlines offset with each other on top and bottom walls). For a jet-to-mainstream mass-now ratio (MR) of 2.0, design parameters were systematically varied for jet-to-mainstream momentum-nux ratios J between 16-64, and orifice spacing-to-duct height ratios S/H between 0.125-1.5. Comparisons were made between geometries optimized for S/H at a specified J. Inline configurations had a unique spacing for best mixing at a specified J. In contrast, staggered configurations had two ''good mixing'' spacings for each J, one corresponding to optimum inline spacing and the other corresponding to optimum wall-impinging jet spacing. The inline configurations, due to their smaller orifice size at optimum S/H, produced better initial mixing characteristics. At downstream locations (e.g., axial distance-to-duct height ratio of 1.5), the optimum staggered configuration produced better mixing than the optimum inline configuration for J of 64; the opposite results were observed for J of 16. Increasing J resulted in better mixing characteristics if each configuration was optimized with respect to orifice spacing. For jet-to-mainstream MRs of 2.0, the optimum mixing equation [(S/H)root J = C] of Holdeman was substantiated, except the optimum mixing constant C increased by a factor of 1.8 for two-sided inline configurations. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP BAIN, DB (reprint author), CFD RES CORP,ENGN,3325 TRIANA BLVD,HUNTSVILLE,AL 35805, USA. NR 27 TC 16 Z9 16 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 885 EP 893 DI 10.2514/3.23913 PG 9 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400001 ER PT J AU CLINE, MC MICKLOW, GJ YANG, SL NGUYEN, HL AF CLINE, MC MICKLOW, GJ YANG, SL NGUYEN, HL TI NUMERICAL-ANALYSIS OF THE FLOWFIELDS IN A STAGED GAS-TURBINE COMBUSTOR SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID SPEEDS AB The KIVA-II code was modified to allow calculation of the flowfields in a staged gas turbine combustor including the air-blast fuel nozzle. The results illustrate the complicated flowfields present in staged combustors. In particular, the thermal protection requirements of the quick-quench mixer used in this study may be similar to those of the rich-burn combustor, despite the presence of the cool dilution jet. Variation of the mass flow split between the fuel nozzle air passages has a significant effect on the velocity and temperature profiles. In addition, the slanted dilution slots form a counter-rotating flowfield. From the results obtained to date, it appears that the modified KIVA-II code can be used to study the effects of various staged combustor designs and operating conditions. C1 UNIV FLORIDA,DEPT MECH ENGN,GAINESVILLE,FL 32601. MICHIGAN TECHNOL UNIV,DEPT MECH ENGN & ENGN MECH,HOUGHTON,MI 49931. NASA,LEWIS RES CTR,COMBUSTER TECHNOL BRANCH,CLEVELAND,OH 44135. RP CLINE, MC (reprint author), LOS ALAMOS NATL LAB,T3 GRP,POB 1663,LOS ALAMOS,NM 87545, USA. NR 27 TC 3 Z9 3 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 894 EP 898 DI 10.2514/3.23914 PG 5 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400002 ER PT J AU PAXSON, DE AF PAXSON, DE TI COMPARISON BETWEEN NUMERICALLY MODELED AND EXPERIMENTALLY MEASURED WAVE-ROTOR LOSS MECHANISMS SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference and Exhibition CY JUN 28-30, 1993 CL MONTEREY, CA SP Amer Inst Aeronaut & Astronaut, Soc Automot Engineers, Amer Soc Mech Engineers, Amer Soc Engn Educ AB A numerical model has been developed that is capable of predicting the performance of a wave-rotor (pressure exchanger) of specified geometry over a wide range of operating conditions. The model can account for the major loss mechanisms of leakage from the tube ends, fluid viscosity, heat transfer to the tube walls, finite tube opening time, shock waves, and nonuniform port flows. It is a one-dimensional flow model that follows a single tube as it rotates past the various stationary ports. Since the model is relatively simple (i.e., one dimensional), it uses little computer time. This makes it suitable for design as well as analytical purposes. This article will present a brief description of the model and then discuss a comparison between the model predictions and several wave-rotor experiments. RP PAXSON, DE (reprint author), NASA,LEWIS RES CTR,SYST DYNAM BRANCH,M-S 77-1,CLEVELAND,OH 44135, USA. NR 21 TC 28 Z9 29 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 908 EP 914 DI 10.2514/3.23916 PG 7 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400004 ER PT J AU SULLIVAN, TA LINNE, D BRYANT, L KENNEDY, K AF SULLIVAN, TA LINNE, D BRYANT, L KENNEDY, K TI IN-SITU-PRODUCED METHANE AND METHANE/CARBON MONOXIDE MIXTURES FOR RETURN PROPULSION FROM MARS SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID EXTRATERRESTRIAL AB A summary of chemical process routes to produce oxygen, water, methane, carbon monoxide, and other fuels is provided. A conceptual design of a plant for use on a robotic Mars sample return mission is presented that predicts that propellant sufficient for a 500-kg return vehicle (dry) can be produced by a plant having a mass of 2.2 metric tons (MT) and using less than 6 kW. The mass includes the imported hydrogen and the power system. This is lower than the 3.34 mT of propellant it replaces, and provides for a much lower Earth launch mass. This design is based on conservative assumptions and existing hardware. Twice the required amount of hydrogen is imported to simplify the processing and to eliminate the need for a separate means of producing the needed amount of oxygen. The volume of the imported hydrogen does have a significant negative impact. Alternatives to pure methane as a fuel are presented. Mixtures of CO and CH4 are considered, with their physical properties and propellant performance predicted, The use of such mixtures in place of pure CH4 in the same sample return mission is analyzed and shown to be competitive. RP SULLIVAN, TA (reprint author), NASA,JOHNSON SPACE FLIGHT CTR,MAIL CODE SL,HOUSTON,TX 77058, USA. NR 19 TC 8 Z9 8 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 1056 EP 1062 DI 10.2514/3.23935 PG 7 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400024 ER PT J AU WANG, TS AF WANG, TS TI NUMERICAL-ANALYSIS OF BASE FLOWFIELD FOR A 4-ENGINE CLUSTERED NOZZLE CONFIGURATION SO JOURNAL OF PROPULSION AND POWER LA English DT Note CT AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference and Exhibition CY JUN 28-30, 1993 CL MONTEREY, CA SP Amer Inst Aeronaut & Astronaut, Soc Automot Engineers, Amer Soc Mech Engineers, Amer Soc Engn Educ RP WANG, TS (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,COMPUTAT FLUID DYNAM BRANCH,HUNTSVILLE,AL 35812, USA. NR 3 TC 8 Z9 8 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 1076 EP 1078 DI 10.2514/3.23938 PG 3 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400027 ER PT J AU BUSHNELL, DM AF BUSHNELL, DM TI HYPERVELOCITY SCRAMJET MIXING ENHANCEMENT SO JOURNAL OF PROPULSION AND POWER LA English DT Note ID TURBULENCE; LAYER; JETS; SWIRL RP BUSHNELL, DM (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 61 TC 14 Z9 15 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD SEP-OCT PY 1995 VL 11 IS 5 BP 1088 EP 1090 DI 10.2514/3.51445 PG 3 WC Engineering, Aerospace SC Engineering GA RU824 UT WOS:A1995RU82400032 ER PT J AU GANAPOL, BD AF GANAPOL, BD TI THE MILNE PROBLEM FOR A SPECULARLY REFLECTING BOUNDARY SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB The standard Milne problem, serving as an analytical benchmark for almost 50 years, is reconsidered in light of the numerical Laplace transform inversion. The application of the numerical inversion greatly reduces the effort in generating highly accurate numerical evaluations of solutions to particular transport problems. Le Caine's results for the integrated intensity are shown to contain only 3 or 4 correct digits. The Milne problem has also been generalized to include a specularly reflecting boundary. RP GANAPOL, BD (reprint author), NASA,AMES RES CTR,ECOSYST SCI & TECHNOL BRANCH,MAIL CODE 242-4,MOFFETT FIELD,CA 94035, USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD SEP PY 1995 VL 54 IS 3 BP 495 EP 508 DI 10.1016/0022-4073(95)00084-X PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA RR232 UT WOS:A1995RR23200005 ER PT J AU ENGMAN, ET AF ENGMAN, ET TI THE USE OF REMOTE-SENSING DATA IN WATERSHED RESEARCH SO JOURNAL OF SOIL AND WATER CONSERVATION LA English DT Article; Proceedings Paper CT International Symposium on Water Research and Management in Semiarid Environments CY NOV 01-03, 1994 CL TUCSON, AZ ID SATELLITE DATA; SPECTRAL DATA; SURFACE; MICROWAVE; RADIATION AB Remote sensing offers watershed researchers a very different type of data from that which they have traditionally worked with. The spatial nature of remote sensing data is its mast unique characteristic, especially when considering that all other hydrologic data are from point measurements. Remote sensing data give the researcher a new tool to use in scaling and in extrapolating point measurements to represent areas. In addition, remote sensing offers entirely new measurements, such as surface soil moisture, snow water content, and surface temperature, which have not been traditionally available to hydrologists. RP ENGMAN, ET (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,HYDROSHER PROC LAB,GREENBELT,MD 20771, USA. NR 29 TC 4 Z9 4 U1 0 U2 0 PU SOIL WATER CONSERVATION SOC PI ANKENY PA 7515 N E ANKENY RD, ANKENY, IA 50021-9764 SN 0022-4561 J9 J SOIL WATER CONSERV JI J. Soil Water Conserv. PD SEP-OCT PY 1995 VL 50 IS 5 BP 438 EP 440 PG 3 WC Ecology; Soil Science; Water Resources SC Environmental Sciences & Ecology; Agriculture; Water Resources GA RX578 UT WOS:A1995RX57800007 ER PT J AU MICOL, JR AF MICOL, JR TI AEROTHERMODYNAMIC MEASUREMENT AND PREDICTION FOR MODIFIED ORBITER AT MACH-6 AND MACH-10 SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Detailed heat-transfer rate distributions measured laterally over the windward surface of an orbiter-like configuration using thin-film resistance heat-transfer gauges and globally using the newly developed relative intensity, two-color thermographic phosphor technique are presented for Mach 6 and 10 in air. The angle of attack was varied from 0 to 40 deg, and the freestream Reynolds number based on the model length was varied from 4 x 10(5) to 6 x 10(6) at Mach 6, corresponding to laminar, transitional, and turbulent boundary layers; the Reynolds number at Mach 10 was 4 x 10(5), corresponding to laminar flow. The primary objective of the present study was to provide detailed benchmark heat-transfer data for the calibration of computational fluid-dynamics codes. Predictions from a Navier-Stokes solver referred to as the Langley aerothermodynamic upwind relaxation algorithm and an approximate boundary-layer solving method known as the axisymmetric analog three-dimensional boundary Layer code are compared with measurement. In general, predicted laminar heat-transfer rates are in good agreement with measurements. RP MICOL, JR (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 34 TC 9 Z9 9 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 737 EP 748 DI 10.2514/3.26678 PG 12 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700001 ER PT J AU BRAUCKMANN, GJ PAULSON, JW WEILMUENSTER, KJ AF BRAUCKMANN, GJ PAULSON, JW WEILMUENSTER, KJ TI EXPERIMENTAL AND COMPUTATIONAL ANALYSIS OF SHUTTLE ORBITER HYPERSONIC TRIM ANOMALY SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SCHEMES AB During the high-Mach-number, high-altitude portion of the first entry of the Shuttle Orbiter, the vehicle exhibited a nose-up pitching moment relative to preflight prediction of approximately Delta C-m = 0.03. This trim anomaly has been postulated to be due to compressibility, viscous, and/or real-gas (lowered specific heat ratio gamma) effects on basic body pitching moment, body-flap effectiveness, or both. In order to assess the relative contribution of each of these effects, an experimental study was undertaken to examine the effects of Mach number, Reynolds number, and ratio of specific heats. Complementary computational solutions were obtained for wind-tunnel and flight conditions. The primary cause of the anomaly was determined to be lower pressures on the aft windward surface of the Orbiter than deduced from hypersonic wind-tunnel tests with ideal- or near-ideal-gas test flow The lower pressure levels are a result of the lowering of the flowfield gamma due to high-temperature effects. This phenomenon was accurately simulated in a hypersonic wind tunnel using a heavy gas, which provided a lower gamma, and was correctly predicted by Navier-Stokes computations using nonequilibrium chemistry. RP BRAUCKMANN, GJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 28 TC 8 Z9 11 U1 2 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 758 EP 764 DI 10.2514/3.26680 PG 7 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700003 ER PT J AU MITCHELTREE, RA GNOFFO, PA AF MITCHELTREE, RA GNOFFO, PA TI WAKE FLOW ABOUT THE MARS-PATHFINDER ENTRY VEHICLE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID AEROBRAKE AB A computational approach is used to describe the aerothermodynamics of the Mars Pathfinder vehicle entering the Mars atmosphere at the maximum heating and maximum deceleration points in its trajectory. Ablating and nonablating boundary conditions are developed which produce maximum recombination of CO2 on the surface. For the maximum heating trajectory point, an axisymmetric, nonablating calculation predicts a stagnation-point value for the convective heating of 115 W/cm(2). Radiative heating estimates predict an additional 5-12 W/cm(2) at the stagnation point. Peak convective heating on the afterbody occurs on the vehicle's flat stern with a value of 5.9% of the stagnation value. The forebody flow exhibits chemical nonequilibrium behavior, and the how is frozen in the near wake. Including ablation injection on the forebody lowers the stagnation-point convective heating 18%. RP MITCHELTREE, RA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 28 TC 26 Z9 31 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 771 EP 776 DI 10.2514/3.26682 PG 6 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700005 ER PT J AU BUCK, GM AF BUCK, GM TI SIMULTANEOUS LUMINESCENCE PRESSURE AND TEMPERATURE-MEASUREMENT SYSTEM FOR HYPERSONIC WIND TUNNELS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Surface pressures and temperatures are determined from visible emission brightness and green-to-red color ratioing of induced luminescence from a ceramic surface with an organic dye coating. A ceramic-dye matrix of porous silica ceramic with an adsorbed dye is developed for high-temperature pressure sensitivity and stability (up to-150 degrees C). Induced luminescence mag be excited using a broad range of incident radiation from visible blue light (488-nm wavelength) to the near ultraviolet (365 nm). Ceramic research models and test samples are fabricated using net-form slip-casting and sintering techniques. Methods of preparation and effects of adsorption film thickness on measurement sensitivity are discussed. With the present I-bit imaging system a 10% pressure measurement uncertainty from 50 to 760 torr is estimated, with an improvement to 5% from 3 to 1500 torr with a 12-bit imaging system. RP BUCK, GM (reprint author), NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681, USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 791 EP 794 DI 10.2514/3.26685 PG 4 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700008 ER PT J AU MAGHAMI, PG JOSHI, SM PRICE, DB AF MAGHAMI, PG JOSHI, SM PRICE, DB TI INTEGRATED CONTROLS - STRUCTURES DESIGN METHODOLOGY FOR FLEXIBLE SPACECRAFT SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper proposes an approach for the design of flexible spacecraft, wherein the structural design and the control system design are performed simultaneously. The integrated design problem is posed as an optimization problem in which both the structural parameters and the control system parameters constitute the design variables, which are used to optimize a common objective function, thereby resulting in an optimal overall design. The approach is demonstrated by application to the integrated design of a geostationary platform, and to a ground-based flexible structure experiment. The numerical results obtained indicate that the integrated design approach generally yields spacecraft designs that are substantially superior to the conventional approach, wherein the structural design and control design are performed sequentially. RP MAGHAMI, PG (reprint author), NASA,LANGLEY RES CTR,GUIDANCE & CONTROL BRANCH,MAIL STOP 161,HAMPTON,VA 23681, USA. NR 11 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 839 EP 844 DI 10.2514/3.26693 PG 6 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700016 ER PT J AU DEVER, JA BRUCKNER, EJ SCHEIMAN, DA STIDHAM, CR AF DEVER, JA BRUCKNER, EJ SCHEIMAN, DA STIDHAM, CR TI CONTAMINATION AND SPACE ENVIRONMENTAL-EFFECTS ON SOLAR-CELLS AND THERMAL CONTROL SURFACES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB For surfaces in low Earth orbit on the International Space Station, contamination may occur from Space Shuttle thruster exhaust, sputter contamination products, and products of silicone degradation. Interaction of the natural low-Earth-orbit environment with the surface contaminants may degrade the performance of solar cells and thermal control coatings. This paper describes laboratory testing in which solar-cell materials and thermal control surfaces were exposed to simulated space environmental effects including contamination, atomic oxygen, ultraviolet radiation, and thermal cycling. Contamination from thruster exhaust in amounts significantly exceeding those expected on the Space Station resulted in increased solar absorptance of surfaces and in degradation of solar-cell performance. Fused silica samples that were subsequently exposed to an environment dominated by atomic oxygen and containing some vacuum-ultraviolet radiation showed reversal of this degradation, Materials which were exposed to vacuum-ultraviolet radiation subsequent to thruster-exhaust contamination showed slight additional degradation in solar absorptance. Despite significant differences between the simulated environments and the low-Earth-orbit environment, these data are useful in suggesting possible trends in performance changes for solar cells and thermal control surfaces due to the interactions between surface contaminants and the natural low-Earth-orbit environment. C1 CLEVELAND STATE UNIV,DEPT PHYS,CLEVELAND,OH 44115. NYMA INC,DEPT AEROSP TECHNOL,BROOKPARK,OH 44142. RP DEVER, JA (reprint author), NASA,LEWIS RES CTR,DIV POWER TECHNOL,ELECTROPHYS BRANCH,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 17 TC 3 Z9 4 U1 2 U2 7 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 850 EP 855 DI 10.2514/3.26695 PG 6 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700018 ER PT J AU MALLA, RB PAI, SS AF MALLA, RB PAI, SS TI PROBABILISTIC RESPONSE OF TRUSS-TYPE SPACE STRUCTURE WITH JOINT AND MEMBER IMPERFECTIONS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A truss-type space structure having a special type of joint defect and member initial imperfection is analyzed to determine its deterministic and probabilistic response. The joint defect is created by considering only the global translation (but not the rotation) degrees of freedom of selected member end nodes-the same as those of the joint at which the member ends meet. The initial member imperfection is considered in terms of some members being initially bent or crooked into a sinusoidal shape. A finite element computational code, ''Numerical Evaluation of Stochastic Structures under Stresses,'' of the NASA Lewis Research Center is used for the determination of the structural response, Results from the study include deterministic and probabilistic vibration frequencies, displacements, and buckling loads, Cumulative probability levels and sensitivity factors are obtained for these responses to delineate the effects on them of random changes in certain geometric, loading, and material design parameters, Results from both the deterministic and probabilistic studies show that the member-end connection defect has significant effects on vibration frequencies, especially the first mode. However, the deterministic results indicate that effects on displacements and buckling loads due to one end connection defect are small. Larger numbers of member end connection (joint) defects, however, can have appreciable influence on the displacement. Initial member imperfections are observed to have small effects on the structural response, Results from the probabilistic analysis indicate that although overall cumulative probabilities of displacements and buckling loads change very slightly as a result of initial member imperfection, different sets of design variables show greater sensitivity than in the case of the joint defect. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP MALLA, RB (reprint author), UNIV CONNECTICUT,DEPT CIVIL & ENVIRONM ENGN,STORRS,CT 06269, USA. NR 16 TC 3 Z9 3 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 870 EP 877 DI 10.2514/3.26698 PG 8 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700021 ER PT J AU TSUYUKI, GT FRENCH, LC AF TSUYUKI, GT FRENCH, LC TI ON-ORBIT TEMPERATURE DISTRIBUTION OF A SUBMILLIMETER-TELESCOPE PRIMARY-REFLECTOR PANEL SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A preliminary detailed primary-mirror thermal analysis has been performed for the Earth-orbiting Submillimeter Imager and Line Survey Telescope. The purpose of the analysis was to determine the spatial temperature distribution in a panel that composes the primary mirror, The primary mirror is formed from seven separate panels, and minimization of the temperature difference across the primary mirror is crucial to optical performance requirements. Previous work indicated that the temperature difference across the entire primary reflector mirror was small, but the nodal granularity was not sufficient to draw the same conclusion for a single panel. A finite difference model with a Large number of nodes for a particular panel was developed. Automated model generator code was developed to facilitate model construction. Steady-state analyses were performed, since the transitory effects of the Earth fluxes are overwhelmed by the solar environment. The analysis indicates that the panel temperature distribution is extremely isothermal, and therefore adequate optical performance is possible. A future, more rigorous analysis now can be performed so that the figure error can be sufficiently quantified. RP TSUYUKI, GT (reprint author), CALTECH,JET PROP LAB,THERMAL & PROPULS ENGN SECT,SPACECRAFT THERMAL ENGN & FLIGHT OPERAT GRP,PASADENA,CA 91109, USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 885 EP 889 DI 10.2514/3.26700 PG 5 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700023 ER PT J AU SUICH, R PATTERSON, R AF SUICH, R PATTERSON, R TI SPACECRAFT EXPECTED-COST ANALYSIS WITH K-OUT-OF-N-G SUBSYSTEMS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SUICH, R (reprint author), CALIF STATE UNIV FULLERTON,DEPT MANAGEMENT SCI INFORMAT SYST,FULLERTON,CA 92634, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD SEP-OCT PY 1995 VL 32 IS 5 BP 927 EP 928 DI 10.2514/3.26710 PG 2 WC Engineering, Aerospace SC Engineering GA TC857 UT WOS:A1995TC85700033 ER PT J AU HEYLIGER, P SARAVANOS, DA AF HEYLIGER, P SARAVANOS, DA TI EXACT FREE-VIBRATION ANALYSIS OF LAMINATED PLATES WITH EMBEDDED PIEZOELECTRIC LAYERS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID POLYMER PLATES; FREQUENCY AB Exact solutions are developed for predicting the coupled electromechanical vibration characteristics of simply supported laminated piezoelectric plates, composed of orthorhombic layers. The three-dimensional equations of motion and the charge equation are solved using the assumptions of the linear theory of piezoelectricity. The through-thickness distributions for the displacements and electrostatic potential are functions of eight constants for each layer of the laminate. Enforcing the continuity and surface conditions results in a linear system of equations representing the behavior of the complete laminate. The determinant of this system must be zero at a resonant frequency. The natural frequencies are found numerically by first incrementally stepping through the frequency spectrum and refining the final frequencies using bisection. Representative frequencies and mode shapes are presented for a variety of lamination schemes and aspect ratios. (C) 1995 Acoustical Society of America. C1 NASA, LEWIS RES CTR, STRUCT MECH BRANCH, CLEVELAND, OH 44135 USA. RP COLORADO STATE UNIV, DEPT CIVIL ENGN, FT COLLINS, CO 80523 USA. NR 14 TC 155 Z9 159 U1 0 U2 15 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 EI 1520-8524 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD SEP PY 1995 VL 98 IS 3 BP 1547 EP 1557 DI 10.1121/1.413420 PG 11 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA RT915 UT WOS:A1995RT91500027 ER PT J AU BROWN, CS SCHUERGER, AC SAGER, JC AF BROWN, CS SCHUERGER, AC SAGER, JC TI GROWTH AND PHOTOMORPHOGENESIS OF PEPPER PLANTS UNDER RED LIGHT-EMITTING-DIODES WITH SUPPLEMENTAL BLUE OR FAR-RED LIGHTING SO JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE LA English DT Article DE CAPSICUM ANNUUM; SOLANACEAE; SPECTRAL QUALITY; LED; PHYTOCHROME ID HIGH-PRESSURE SODIUM; SPECTRAL FILTERS; QUALITY; LETTUCE; WHEAT AB Light-emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems and photobiological research, They have small size, low mass, a long functional life, and narrow spectral output,In this study, we measured the growth and dry matter partitioning of 'Hungarian Wax' pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LE;Ds with supplemental blue or far-red radiation or under broad spectrum metal halide (MH) lamps, Additionally, we describe the thermal and spectral characteristics of these sources, The LEDs used in this study had a narrow bandwidth at half peak height (25 nm) and a focused maximum spectral output at 660 nm for the red and 735 nm for the far-red, Near infrared radiation (800 to 3000 nm) was below detection and thermal infrared radiation (3000 to 50,000 nm) was lower in the LEDs compared to the MH source, Although the red to far-red ratio varied considerably, the calculated phytochrome photostationary state (phi) was only slightly different between the radiation sources, Plant biomass was reduced when peppers were grown under red LEDs in the absence of blue wavelengths compared to plants grown under supplemental blue fluorescent lamps or MH lamps, The addition of far-red radiation resulted in taller plants with greater stem mass than red LEDs alone, There were fewer leaves under red or red plus far-red radiation than with lamps producing blue wavelengths, These results indicate that red LEDs may be suitable, in proper combination with other wavelengths of light, for the culture of plants in tightly controlled environments such as space-based plant culture systems. C1 WALT DISNEY WORLD CO,LAKE BUENA VISTA,FL 32830. NASA,BIOMED OPERAT & RES OFF,KENNEDY SPACE CTR,FL 32899. RP BROWN, CS (reprint author), DYNAMAC CORP,MAIL CODE DYN-3,KENNEDY SPACE CTR,FL 32899, USA. NR 25 TC 151 Z9 172 U1 4 U2 49 PU AMER SOC HORTICULTURAL SCIENCE PI ALEXANDRIA PA 701 NORTH SAINT ASAPH STREET, ALEXANDRIA, VA 22314-1998 SN 0003-1062 J9 J AM SOC HORTIC SCI JI J. Am. Soc. Hortic. Sci. PD SEP PY 1995 VL 120 IS 5 BP 808 EP 813 PG 6 WC Horticulture SC Agriculture GA RN055 UT WOS:A1995RN05500019 PM 11540133 ER PT J AU MANNEY, GL ZUREK, RW LAHOZ, WA HARWOOD, RS GILLE, JC KUMER, JB MERGENTHALER, JL ROCHE, AE ONEILL, A SWINBANK, R WATERS, JW AF MANNEY, GL ZUREK, RW LAHOZ, WA HARWOOD, RS GILLE, JC KUMER, JB MERGENTHALER, JL ROCHE, AE ONEILL, A SWINBANK, R WATERS, JW TI LAGRANGIAN TRANSPORT CALCULATIONS USING UARS DATA .1. PASSIVE TRACERS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERE RESEARCH SATELLITE; STRATOSPHERIC POLAR VORTEX; MICROWAVE LIMB SOUNDER; SOUTHERN-HEMISPHERE; WINTER; OZONE; AIR; MLS; EVOLUTION; CLAES AB The transport of passive tracers observed by the Upper Atmosphere Research Satellite is simulated using computed three-dimensional trajectories of approximate to 100 000 air parcels initialized on a stratospheric grid, with horizontal winds provided by the United Kingdom Meteorological Office data assimilation system, and vertical (cross isentropic) velocities computed using a fast radiation code. The conservative evolution of trace constituent fields is estimated over 20-30-day periods by assigning to each parcel the observed mixing ratio of the long-lived trace gases N2O and CH4 observed by the Cryogenic Limb Array Etalon Spectrometer(CLAES) and H2O observed by the Microwave Limb Sounder (MLS) on the initialization date. Agreement between calculated and observed fields is best inside the polar vortex and is better in the Arctic than in the Antarctic. Although there is not always detailed agreement outside the vortex, the trajectory calculations still reproduce the average large-scale characteristics of passive tracer evolution in midlatitudes. In late winter, synoptic maps from trajectory calculations reproduce all major features of the observations, including large tongues or blobs of material drawn from low latitudes into the region of the anticyclone during February-March 1993. Comparison of lower-stratospheric observations of the CLAES tracers with the calculations suggests that discontinuities seen in CLAES data in the Antarctic late winter lower stratosphere are inconsistent with passive tracer behavior. In the Arctic, and in the Antarctic late winter, MLS H2O observations show behavior that is inconsistent with calculations and with that expected for passive tracers inside the polar vortex in the middle-to-upper stratosphere. Diabatic descent rates in the Arctic lower stratosphere deduced from data are consistent with those from the calculations. In the Antarctic lower stratosphere, the calculations appear to underestimate the diabatic descent. The agreement between large-scale features of calculated and observed tracer fields supports the utility of these calculations in diagnosing trace species transport in the winter polar vortex. C1 CTR GLOBAL ATMOSPHER RES,READING,BERKS,ENGLAND. UNIV EDINBURGH,EDINBURGH,MIDLOTHIAN,SCOTLAND. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. METEOROL OFF,BRACKNELL RB12 2SZ,BERKS,ENGLAND. RP MANNEY, GL (reprint author), CALTECH,JET PROP LAB,MAIL STOP 183-701,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 40 TC 31 Z9 31 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD SEP 1 PY 1995 VL 52 IS 17 BP 3049 EP 3068 DI 10.1175/1520-0469(1995)052<3049:LTCUDP>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RR005 UT WOS:A1995RR00500001 ER PT J AU MANNEY, GL ZUREK, RW FROIDEVAUX, L WATERS, JW ONEILL, A SWINBANK, R AF MANNEY, GL ZUREK, RW FROIDEVAUX, L WATERS, JW ONEILL, A SWINBANK, R TI LAGRANGIAN TRANSPORT CALCULATIONS USING UARS DATA .2. OZONE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERE RESEARCH SATELLITE; MICROWAVE LIMB SOUNDER; POLAR VORTEX; WINTER; EVOLUTION; MLS AB Trajectory calculations are used to examine ozone transport in the polar winter stratosphere during periods of the Upper Atmosphere Research Satellite (UARS) observations. The value of these calculations for determining mass transport was demonstrated previously using UARS observations of long-lived tracers. In the middle stratosphere, the overall ozone behavior observed by the Microwave Limb Sounder in the polar vortex is reproduced by this purely dynamical model. Calculations show the evolution of ozone in the lower stratosphere during early winter to be dominated by dynamics in December 1992 in the Arctic. Calculations for June 1992 in the Antarctic show evidence of chemical ozone destruction and indicate that approximate to 50% of the chemical destruction may be masked by dynamical effects, mainly diabatic descent, which bring higher ozone into the lower-stratospheric vortex. Estimating differences between calculated and observed fields suggests that dynamical changes masked approximate to 20%-35% of chemical ozone loss during late February and early March 1993 in the Arctic. In the Antarctic late winter, in late August and early September 1992, below approximate to 520 K, the evolution of vortex-averaged ozone is entirely dominated by chemical effects; above this level, however, chemical ozone depletion can be partially or completely masked by dynamical effects. Our calculations for 1992 showed that chemical loss was nearly completely compensated by increases due to diabatic descent at 655 K. C1 CTR GLOBAL ATMOSPHER MODELLING,READING,BERKS,ENGLAND. METEOROL OFF,BRACKNELL RB12 2SZ,BERKS,ENGLAND. RP MANNEY, GL (reprint author), CALTECH,JET PROP LAB,MAIL STOP 183-701,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 21 TC 42 Z9 42 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD SEP 1 PY 1995 VL 52 IS 17 BP 3069 EP 3081 DI 10.1175/1520-0469(1995)052<3069:LTCUDP>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RR005 UT WOS:A1995RR00500002 ER PT J AU KRASICH, M AF KRASICH, M TI ON GIVING SO JOURNAL OF THE INSTITUTE OF ENVIRONMENTAL SCIENCES LA English DT Editorial Material RP KRASICH, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 301-466,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCI PI MOUNT PROSPECT PA 940 E NORTHWEST HIGHWAY, MOUNT PROSPECT, IL 60056 SN 1052-2883 J9 J INST ENVIRON SCI JI J. Inst. Environ. Sci. PD SEP-OCT PY 1995 VL 38 IS 5 BP 14 EP 14 PG 1 WC Engineering, Environmental; Environmental Sciences; Instruments & Instrumentation SC Engineering; Environmental Sciences & Ecology; Instruments & Instrumentation GA TB541 UT WOS:A1995TB54100002 ER PT J AU FORBES, GW WALLACE, JK AF FORBES, GW WALLACE, JK TI CAN THE BOUNDS TO SYSTEM PERFORMANCE IN GEOMETRICAL-OPTICS BE ATTAINED SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article AB The laws of geometrical optics establish that certain imaging properties cannot be realized. For example, it is impossible to image sharply any three-dimensional region with nonunit magnification. Hamilton's characteristic functions not only offer a simple means to determine whether certain properties are unattainable but have also been used to derive bounds in answer to the more practical question: ''How closely can any particular unattainable ideal be approached?'' Basic matters that relate to these bounds and whether they can be attained by realizable systems are considered here. Limits to the task of imaging more than a single plane object are used for illustration. A fundamental constraint has been overlooked in earlier research on this topic and a new hound is derived for the performance of systems in a classic lens design problem, but new questions emerge and remain unanswered. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP FORBES, GW (reprint author), MACQUARIE UNIV,DEPT PHYS,SYDNEY,NSW 2109,AUSTRALIA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD SEP PY 1995 VL 12 IS 9 BP 2064 EP 2071 DI 10.1364/JOSAA.12.002064 PG 8 WC Optics SC Optics GA RR754 UT WOS:A1995RR75400025 ER PT J AU HEXMOOR, H KORTENKAMP, D AF HEXMOOR, H KORTENKAMP, D TI ISSUES ON BUILDING SOFTWARE FOR HARDWARE AGENTS SO KNOWLEDGE ENGINEERING REVIEW LA English DT Article C1 NASA,JOHNSON SPACE CTR,METRICA INC,ROBOT & AUTOMAT GRP,HOUSTON,TX 77085. RP HEXMOOR, H (reprint author), SUNY BUFFALO,DEPT COMP SCI,226 BELL HALL,BUFFALO,NY 14260, USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0269-8889 J9 KNOWL ENG REV JI Knowl. Eng. Rev. PD SEP PY 1995 VL 10 IS 3 BP 301 EP 304 PG 4 WC Computer Science, Artificial Intelligence SC Computer Science GA TD801 UT WOS:A1995TD80100003 ER PT J AU HOFLUND, GB GARDNER, SD SCHRYER, DR UPCHURCH, BT KIELIN, EJ AF HOFLUND, GB GARDNER, SD SCHRYER, DR UPCHURCH, BT KIELIN, EJ TI EFFECT OF CO2 ON THE PERFORMANCE OF AU/MNOX AND PT/SNOX LOW-TEMPERATURE CO OXIDATION CATALYSTS SO LANGMUIR LA English DT Article ID REDUCIBLE OXIDE MATERIALS; SURFACE CHARACTERIZATION; CARBON-MONOXIDE; GOLD CATALYSTS; PT3SN ALLOY; PRETREATMENT; BEHAVIOR; REDUCTION; EXPOSURE; TIO2 AB The performance of Au/MnOx and Pt/SnOx catalysts for low-temperature (<100 degrees C) CO oxidation under stoichiometric conditions has been examined for the case where 8% or 16% CO2 is added to the feed gas. High concentrations of CO2 in the reaction gas mixture adversely affect the behavior of these catalysts due to CO2 retention at their surfaces. The magnitude of this detrimental effect can be reduced by adding an Fe promotor to both types of catalysts and optimizing various preparative and pretreatment variables. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP HOFLUND, GB (reprint author), UNIV FLORIDA,DEPT CHEM ENGN,GAINESVILLE,FL 32611, USA. NR 28 TC 25 Z9 25 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0743-7463 J9 LANGMUIR JI Langmuir PD SEP PY 1995 VL 11 IS 9 BP 3431 EP 3434 DI 10.1021/la00009a026 PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA RX243 UT WOS:A1995RX24300026 ER PT J AU FISHER, TH CHAO, P UPTON, CG DAY, AJ AF FISHER, TH CHAO, P UPTON, CG DAY, AJ TI ONE-DIMENSIONAL AND 2-DIMENSIONAL NMR-STUDY OF RESOL PHENOL-FORMALDEHYDE PREPOLYMER RESINS SO MAGNETIC RESONANCE IN CHEMISTRY LA English DT Article DE NMR; H-1 NMR; C-13 NMR; PHENOL-FORMALDEHYDE RESINS ID NUCLEAR MAGNETIC-RESONANCE; STATE C-13 NMR; THERMAL-DECOMPOSITION; INTRINSIC-VISCOSITY; CHEMICAL-SHIFTS; MODEL COMPOUNDS; SPECTROSCOPY; HEXAMETHYLENETETRAMINE; CHROMATOGRAPHY; POLARIZATION AB A one- and two-dimensional NMR study was performed on three commercial resol phenol-formaldehyde (PF) prepolymer resins. H-1, C-13, CSCM and DQF COSY NMR spectral data, in aceton-d(6), were obtained on each resin and on PF model compounds: phenol, five methylolphenols, four diphenylmethanes, two formals, two dibenzyl ethers and two dibenzylamines. Gated-decoupled C-13 experiments, using 2,4,6-trimethylphenol as internal standard, were used to quantitate the major components present in each of the three resins. The major chemical differences of the three resins were noted. A DQF COSY method was developed that allowed the qualitative identification of most of the major phenolic components present in each of the PF resins. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. THIOKOL HSO,HUNTSVILLE,AL 35806. RP FISHER, TH (reprint author), MISSISSIPPI STATE UNIV,DEPT CHEM,MISSISSIPPI STATE,MS 39762, USA. NR 46 TC 26 Z9 26 U1 2 U2 11 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0749-1581 J9 MAGN RESON CHEM JI Magn. Reson. Chem. PD SEP PY 1995 VL 33 IS 9 BP 717 EP 723 DI 10.1002/mrc.1260330905 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA RU581 UT WOS:A1995RU58100004 ER PT J AU BAAKLINI, GY BHATT, RT ECKEL, AJ ENGLER, P CASTELLI, MG RAUSER, RW AF BAAKLINI, GY BHATT, RT ECKEL, AJ ENGLER, P CASTELLI, MG RAUSER, RW TI X-RAY MICROTOMOGRAPHY OF CERAMIC AND METAL-MATRIX COMPOSITES SO MATERIALS EVALUATION LA English DT Article DE AERONAUTICS; CERAMICS; COMPOSITE MATERIALS; COMPUTED TOMOGRAPHY; DEFECTS; DISBONDS; ENGINES; METAL MATRIX COMPOSITES; NONDESTRUCTIVE EVALUATION; X-RADIOGRAPHY AB Capabilities and limitations of X-ray computed microtomography (CT) in characterizing relevant composite material issues as identified during manufacturing processes were investigated. Damage in engine subcomponents was evaluated and compared with damage detected in pedigreed coupon type specimens. The system used is a newly developed state-of-the-art X-ray computed tomography system capable of providing digital radiography, computed tomography and computed laminography. CT was found viable for characterizing processing defects and coating effect in thermally shocked carbon fiber reinforced silicon carbide matrix (C/SiC) samples. CT results from mechanically tested silicon carbide fiber reinforced reaction bonded silicon nitride (SiC/RBSN) matrix sample were evaluated and compared to engine tested SiC/RBSN turbine vanes. Thermomechanically cycled SiC (SCS-6) fiber reinforced Timetal 21S samples showed viability of CT in detecting composite constituents and limitations of CT in detecting matrix and fiber cracking. Also an engineering analysis approach was proposed to continuously integrate nondestructive evaluation modalities in the design-manufacturing-prototyping cycle of engine components. C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44114. NYMA INC,CLEVELAND,OH 44142. RP BAAKLINI, GY (reprint author), NASA,LEWIS RES CTR,MS 6-1,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 13 TC 6 Z9 7 U1 1 U2 6 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD SEP PY 1995 VL 53 IS 9 BP 1040 EP 1044 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA RT981 UT WOS:A1995RT98100008 ER PT J AU PROSSER, WH JACKSON, KE KELLAS, S SMITH, BT MCKEON, J FRIEDMAN, A AF PROSSER, WH JACKSON, KE KELLAS, S SMITH, BT MCKEON, J FRIEDMAN, A TI ADVANCED WAVE-FORM-BASED ACOUSTIC-EMISSION DETECTION OF MATRIX CRACKING IN COMPOSITES SO MATERIALS EVALUATION LA English DT Article DE ACOUSTIC EMISSION; COMPOSITE MATERIALS; CRACKS; GRAPHITE-EPOXY COMPOSITES; NONDESTRUCTIVE EVALUATION; TRANSVERSE MATRIX CRACKING ID TRANSVERSE CRACKING; EPOXY; STRENGTH; GLASS; WAVES AB An advanced, waveform based acoustic emission system was used to study the initiation of transverse matrix cracking in cross-ply graphite/epoxy composites. The acoustic emission signals were detected with broad band, high fidelity sensors, and digitized for analysis. Plate wave propagation analysis was used to discriminate noise signals from those generated by cracks. The noise signals were confirmed to have originated in the specimen grip region by a new, highly accurate form of location analysis which was independent of threshold setting. Six different specimen thicknesses ([0(n), 90(n), 0(n)],n = 1 to 6) were tested under stroke controlled, quasi-static tensile loading. The presence and location of the cracks were confirmed post test by microscopy. Back scatter ultrasonics, penetrant enhanced X-ray techniques, and in limited cases, destructive sectioning and microscopy were also used to determine the length of the cracks. For thicker specimens (n > 2), there was an exact, one to one correspondence between acoustic emission crack signals and observed cracks. The lengths of the cracks in these specimens extended the full specimen width. Precise linear location of the crack position was demonstrated. The average absolute value of the difference between the microscopy determined crack location and the acoustic emission crack location was 3.2 mm (0.225 in.) for a nominal sensor gage length of 152 mm (6 in.). A four-sensor array was used that improved the linear location accuracy and provided the lateral position of the crack initiation site. This allowed determination of whether the cracks initiated in the interior bulk of the specimens or along the free edges. For all cracks, the location of the crack initiation site was at one of the edges of the specimen. The cracks were more difficult to detect with acoustic emission in the thin specimens (n less than or equal to 2). The cracks in these specimens also initiated at the specimen edge, but did not immediately propagate across the specimen width. They generated significantly smaller amplitude acoustic emission signals. These measurements demonstrated that the same source mechanism can generate a wide range of acoustic emission signal amplitudes. C1 NASA, LANGLEY RES CTR, LOCKHEED ENGN & SCI CO, HAMPTON, VA 23681 USA. COLL WILLIAM & MARY, WILLIAMSBURG, VA 23187 USA. RP PROSSER, WH (reprint author), USA, NASA, LANGLEY RES CTR, MS 231, HAMPTON, VA 23681 USA. NR 37 TC 114 Z9 117 U1 1 U2 19 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD SEP PY 1995 VL 53 IS 9 BP 1052 EP 1058 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA RT981 UT WOS:A1995RT98100010 ER PT J AU LERCH, B HALFORD, G AF LERCH, B HALFORD, G TI EFFECTS OF CONTROL MODE AND R-RATIO ON THE FATIGUE BEHAVIOR OF A METAL-MATRIX COMPOSITE SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT TMS/ASM Symposium on Mechanisms and Mechanics of MMC Fatigue CY OCT 02-06, 1994 CL CHICAGO, IL SP TMS, ASM DE CONTROL MODE; R-RATIO; FATIGUE; METAL MATRIX COMPOSITE AB Thick specimens of [0](32) SiC/Ti-15-3 were cycled under a variety of loading conditions. Specimens were fatigued in strain- and load-controlled modes at both R = 0 (zero-tension) and R = -1 (fully reversed) loading ratios. In addition, a hybrid strain-controlled mode at R = 0 was used to simulate the true strain-controlled behaviour. The strain-controlled specimens had longer lives compared with the load-controlled specimens when cycled al an R-ratio of zero. Under fully reversed loading, there was no difference between the strain- and load-controlled modes. The hybrid strain-controlled data were found to approximate the load-controlled data better, rather than the true strain-controlled situation. Damage occurred through transverse fibre cracks for R = 0 loading for both the load- and strain-controlled modes. However, fully reversed loading caused matrix cracking to be the operative damage mechanism. RP LERCH, B (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 9 TC 22 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD SEP PY 1995 VL 200 IS 1-2 BP 47 EP 54 DI 10.1016/0921-5093(95)07005-2 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TA287 UT WOS:A1995TA28700007 ER PT J AU BRINDLEY, PK BARTOLOTTA, PA AF BRINDLEY, PK BARTOLOTTA, PA TI FAILURE MECHANISMS DURING ISOTHERMAL FATIGUE OF SIC/TI-24AL-11NB COMPOSITES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT TMS/ASM Symposium on Mechanisms and Mechanics of MMC Fatigue CY OCT 02-06, 1994 CL CHICAGO, IL SP TMS, ASM DE FAILURE; ISOTHERMAL FATIGUE; TITANIUM ALUMINIDE COMPOSITES ID ALLOY MATRIX COMPOSITES; FRACTURE MECHANISMS; TEMPERATURE AB Failure mechanisms during isothermal fatigue of unidirectional SiC/Ti-24Al-11Nb (at.%) composites have been determined by microstructural analysis of samples from tests interrupted prior to the end of life and from tests conducted to failure. Specimens from three regions of life were examined based on the maximum strain from a fatigue life diagram: Region I (high strain). Region II (mid-strain) and Region III (low strain). Crack lengths were also measured from interrupted samples and compared based on temperature (23-815 degrees C), region of life and numbers of cycles. Region I was controlled by fibre-dominated failure. A transition zone was observed between Regions I and II due to competition between failure mechanisms. Failure in Region II was generally described as surface-initiated cracking with varying amounts of fibre bridging. However, the specific descriptions of crack propagation through the fibres and matrix varied with strain and temperature over this broad region. Region III exhibited endurance behaviour at 23 degrees C with no cracking after 10(6) cycles. However at 425 degrees C, surface-initialed cracking was observed after 10(6) cycles with fractured fibres in the crack wake. If endurance behaviour exists for conditions of isothermal fatigue in air at temperatures of greater than or equal to 425 degrees C, it may only be found at very low strains and at greater than 10(6) cycles. RP BRINDLEY, PK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 30 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD SEP PY 1995 VL 200 IS 1-2 BP 55 EP 67 DI 10.1016/0921-5093(95)07013-3 PG 13 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TA287 UT WOS:A1995TA28700008 ER PT J AU JOHNSON, WS MILLER, JL MIRDAMADI, M AF JOHNSON, WS MILLER, JL MIRDAMADI, M TI FRACTOGRAPHIC INTERPRETATION OF FAILURE MECHANISMS IN TITANIUM MATRIX COMPOSITES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT TMS/ASM Symposium on Mechanisms and Mechanics of MMC Fatigue CY OCT 02-06, 1994 CL CHICAGO, IL SP TMS, ASM DE TITANIUM MATRIX COMPOSITES; FAILURE; FRACTOGRAPHIC STUDY AB Titanium matrix composites (TMC) offer a combination of good mechanical properties and high temperature durability that make them attractive candidate materials for advanced engine components and high temperature structural applications. In such applications the material will be subjected to changing mechanical loads and temperature fluctuations, resulting in complex stress states within the constituents of the composite, This study examines how the various loading conditions on the TMCs are reflected in the fracture behaviour to gain insight into the damage mechanisms active in these materials. A fractographic study was conducted on several different TMC specimens, fabricated from Ti-15-3 and Timetal 21S alloys and SCS-6 fibres, that have been subjected to various thermomechanical loading conditions. The analysis showed that the Ti-15-3 composites were more susceptible to damage during sustained load at elevated temperature than the Timetal 21S composites. For both materials, striations only appear during elevated temperature fatigue when the residual processing stresses are relieved. During the Generic Hypersonic Flight Profile (GHFP) tests, the higher temperatures of the Mission I profile induce more damage in the Timetal 21S composites. The striations appear in the composites containing centre holes, unlike the unnotched specimens, indicating that the combined effect of stress concentration due to the hole and an underdeveloped fibre bridging zone may have resulted in crack closure. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. ANALYT SERV & MAT INC,HAMPTON,VA 23666. RP JOHNSON, WS (reprint author), GEORGIA INST TECHNOL,DEPT MAT SCI & ENGN,ATLANTA,GA 30332, USA. NR 15 TC 6 Z9 6 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD SEP PY 1995 VL 200 IS 1-2 BP 78 EP 88 DI 10.1016/0921-5093(95)07016-8 PG 11 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TA287 UT WOS:A1995TA28700010 ER PT J AU MAJUMDAR, BS LERCH, BA AF MAJUMDAR, BS LERCH, BA TI STRUCTURAL-MATERIALS - PROPERTIES, MICROSTRUCTURE AND PROCESSING - PROCEEDINGS OF THE TMS/ASM SYMPOSIUM ON MECHANISMS AND MECHANICS OF MMC-FATIGUE, OCTOBER 2-6, 1994, CHICAGO, IL, USA - FOREWORD SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Editorial Material C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP MAJUMDAR, BS (reprint author), UNIVERSAL ENERGY SYST INC,DAYTON XENIA RD,DAYTON,OH 45432, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD SEP PY 1995 VL 200 IS 1-2 BP R7 EP R7 DI 10.1016/0921-5093(95)80042-5 PG 1 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TA287 UT WOS:A1995TA28700001 ER PT J AU SRIVASTAVA, SK IGA, I RAO, MVVS AF SRIVASTAVA, SK IGA, I RAO, MVVS TI A SEGMENTED TIME-OF-FLIGHT MASS-SPECTROMETER SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article AB The present paper describes the design of a time-of-flight mass spectrometer (TOFMS) in which the single flight tube of a conventional TOFMS has been replaced by several cylindrical electrostatic lenses in tandem. By a judicious choice of voltages on these lenses, an improved TOFMS has been realized which has a superior mass and energy resolution, shorter flight lengths, excellent signal-to-noise ratio and less stringent requirements on the bias voltages. RP CALTECH, JET PROP LAB, OAK GROVE DR, PASADENA, CA 91109 USA. RI Iga, Ione/C-1273-2015 NR 4 TC 3 Z9 3 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD SEP PY 1995 VL 6 IS 9 BP 1379 EP 1382 DI 10.1088/0957-0233/6/9/020 PG 4 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RW654 UT WOS:A1995RW65400021 ER PT J AU ANDERSON, KR GROZA, JR DRESHFIELD, RL ELLIS, D AF ANDERSON, KR GROZA, JR DRESHFIELD, RL ELLIS, D TI HIGH-PERFORMANCE DISPERSION-STRENGTHENED CU-8 CR-4 NB ALLOY SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID CU-8CR-4NB ALLOY AB A new high-temperature-strength, high-conductivity Cu-Cr-Nb alloy with a Cr:Nb ratio of 2:1 was developed to achieve improved performance and durability. The Cu-X Cr-4 No alloy studied has demonstrated remarkable thermal and microstructural stability after long exposures at temperatures up to 0.98 T-m. This stability was mainly attributed to the slow coarsening kinetics of the Cr2Nb precipitates present in the alloy. At all temperatures, the microstructure consists of a bimodal and sometimes trimodal distribution of strengthening Cr,Nb precipitates, depending on precipitation condition, i.e., from liquid or solid solution, and cooling rates. These precipitates remain in the same size range, i.e., large precipitates of approximately 1 mu m and small precipitates less than 300 nm, and effectively pin the grain boundaries, thus retaining a fine grain size of 2.7 mu m after 100 hours at 1323 K. This grain-boundary pinning and sluggish coarsening of Cr2Nb particles explain the retention of good mechanical properties after prolonged holding at very high temperatures, e.g., two-thirds of the original yield strength after aging for 100 hours at 1273 K, The main sources of strengthening are the Hall-Fetch and Orowan mechanisms due mostly to small particles. The coarsening kinetics of the large precipitates are most likely governed by grain-boundary diffusion and, to a lesser extent, volume diffusion mechanisms. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP ANDERSON, KR (reprint author), UNIV CALIF DAVIS,DEPT CHEM ENGN & MAT SCI,DAVIS,CA 95616, USA. NR 17 TC 45 Z9 45 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD SEP PY 1995 VL 26 IS 9 BP 2197 EP 2206 DI 10.1007/BF02671235 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA RR270 UT WOS:A1995RR27000001 ER PT J AU ALLEN, CC MORRIS, RV MCKAY, DS AF ALLEN, CC MORRIS, RV MCKAY, DS TI EXPERIMENTAL SPACE WEATHERING OF LUNAR SOILS SO METEORITICS LA English DT Meeting Abstract C1 LOCKHEED MARTIN,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 4 Z9 5 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 479 EP 480 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800004 ER PT J AU BENEDIX, GK MCCOY, TJ KEIL, K AF BENEDIX, GK MCCOY, TJ KEIL, K TI SILICATE INCLUSIONS IN IAB IRONS - CORRELATIONS BETWEEN METAL COMPOSITION AND INCLUSION PROPERTIES, AND INFERENCES FOR THEIR ORIGIN SO METEORITICS LA English DT Meeting Abstract ID METEORITE GROUPS IAB; IIICD C1 UNIV HAWAII MANOA,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 10 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 485 EP 485 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800015 ER PT J AU CASSEN, P AF CASSEN, P TI CHONDRITIC FRACTIONATION PATTERNS FROM COUPLED THERMAL-COAGULATION MODELS OF THE SOLAR NEBULA SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 6 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 495 EP 495 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800036 ER PT J AU COOPER, GW THIEMENS, MH JACKSON, T CHANG, S AF COOPER, GW THIEMENS, MH JACKSON, T CHANG, S TI SULFUR AND HYDROGEN ISOTOPIC ANOMALIES IN ORGANIC-COMPOUNDS FROM THE MURCHISON METEORITE SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF SAN DIEGO,DEPT CHEM,LA JOLLA,CA 92093. NR 6 TC 5 Z9 5 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 500 EP 500 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800046 ER PT J AU GARRISON, DH BOGARD, DD AF GARRISON, DH BOGARD, DD TI AR-39 AR-40 AGES OF SILICATES FROM IIE IRON-METEORITES SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NR 9 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 508 EP 508 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800062 ER PT J AU GARVIN, JB GRIEVE, RAF SCHNETZLER, CC AF GARVIN, JB GRIEVE, RAF SCHNETZLER, CC TI SATELLITE REMOTE-SENSING SIGNATURES OF IMPACT STRUCTURES SO METEORITICS LA English DT Meeting Abstract ID TERRESTRIAL IMPACT C1 NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. GEOL SURVEY CANADA,OTTAWA,ON K1A 0Y,CANADA. UNIV MARYLAND,DEPT GEOG,COLLEGE PK,MD 20742. NR 5 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 509 EP 509 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800063 ER PT J AU HANSON, BZ JONES, JH MITTLEFEHLDT, DW JUREWICZ, AJG AF HANSON, BZ JONES, JH MITTLEFEHLDT, DW JUREWICZ, AJG TI VANADIUM PARTITIONING AMONG PHASES RELEVANT TO EUCRITE PETROGENESIS SO METEORITICS LA English DT Meeting Abstract C1 SUNY ALBANY,DEPT GEOL,ALBANY,NY 12222. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. US SYNTHET CORP,PROVO,UT 84606. NR 4 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 516 EP 517 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800078 ER PT J AU HIROI, T PIETERS, CM ZOLENSKY, ME LIPSCHUTZ, ME AF HIROI, T PIETERS, CM ZOLENSKY, ME LIPSCHUTZ, ME TI POSSIBLE THERMAL METAMORPHISM ON THE C-ASTEROIDS SEEN FROM THE 3-MU-M HYDRATION BAND IN COMPARISON WITH HEATED CI/CM METEORITES SO METEORITICS LA English DT Meeting Abstract C1 BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. NR 8 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 521 EP 521 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800087 ER PT J AU KELLER, LP MCKAY, DS AF KELLER, LP MCKAY, DS TI THE ORIGIN OF AMORPHOUS RIMS ON LUNAR SOIL GRAINS - REVISITED SO METEORITICS LA English DT Meeting Abstract C1 MVA INC,NORCROSS,GA 30093. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 10 Z9 10 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 526 EP 526 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800100 ER PT J AU KELLER, LP THOMAS, KL BRADLEY, JP MCKAY, DS AF KELLER, LP THOMAS, KL BRADLEY, JP MCKAY, DS TI NITROGEN IN INTERPLANETARY DUST PARTICLES SO METEORITICS LA English DT Meeting Abstract ID ABUNDANCES; CARBON C1 MVA INC,NORCROSS,GA 30093. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 8 TC 10 Z9 10 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 526 EP 527 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800101 ER PT J AU KRING, DA MELOSH, HJ HUNTEN, DM AF KRING, DA MELOSH, HJ HUNTEN, DM TI ALTERATION AND DEHYDRATION IN THE PARENT ASTEROID OF ALLENDE SO METEORITICS LA English DT Meeting Abstract C1 UNIV HAWAII MANOA,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 11 TC 3 Z9 3 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 530 EP 531 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800111 ER PT J AU LERNER, NR AF LERNER, NR TI CARBOXYLIC-ACIDS AS INDICATORS OF PARENT BODY CONDITIONS SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,PLANETARY BIOL BRANCH,MOFFETT FIELD,CA 94035. NR 4 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 535 EP 536 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800121 ER PT J AU LINDSTROM, M ALLEN, J AF LINDSTROM, M ALLEN, J TI METEORITES FOR K-12 CLASSROOMS - NASA METEORITE EDUCATIONAL-MATERIALS SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NASA,LOCKHEED JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 537 EP 537 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800124 ER PT J AU LOFGREN, GE FAHEY, AJ WASSERBURG, GJ AF LOFGREN, GE FAHEY, AJ WASSERBURG, GJ TI A STUDY OF TRACE-ELEMENT PARTITIONING BETWEEN PYROXENE AND ANGRITIC MELT - EQUILIBRIUM AND KINETIC EFFECTS INCLUDING SECTOR ZONING IN PYROXENE SO METEORITICS LA English DT Meeting Abstract ID ANGRA-DOS-REIS C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. CALTECH,DIV GEOL & PLANETARY SCI,LUNAT ASYLUM,PASADENA,CA 91125. RI Fahey, Albert/C-5611-2015 NR 7 TC 1 Z9 1 U1 0 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 538 EP 538 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800126 ER PT J AU LONGHI, J JUREWICZ, AJG MITTLEFEHLDT, DW JONES, JH AF LONGHI, J JUREWICZ, AJG MITTLEFEHLDT, DW JONES, JH TI GRAPHICAL ANALYSIS OF ANGRITE PETROGENESIS SO METEORITICS LA English DT Meeting Abstract ID SYSTEM C1 LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964. US SYNTHET CORP,PROVO,UT 84606. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 4 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 538 EP 538 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800127 ER PT J AU MCCOY, TJ AF MCCOY, TJ TI SILICATE-BEARING IIE IRONS - EARLY MIXING AND DIFFERENTIATION IN A CORE-MANTLE ENVIRONMENT AND SHOCK RESETTING OF AGES SO METEORITICS LA English DT Meeting Abstract ID METEORITES; INCLUSIONS C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 13 TC 14 Z9 14 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 542 EP 543 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800136 ER PT J AU MCKAY, G CROZAZ, G MIKOUCHI, T MIYAMOTO, M AF MCKAY, G CROZAZ, G MIKOUCHI, T MIYAMOTO, M TI EXOTIC OLIVINE IN ANTARCTIC ANGRITES LEWIS-CLIFF-87051 AND ASUKA-881371 SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. WASHINGTON UNIV,ST LOUIS,MO 63130. UNIV TOKYO,TOKYO 113,JAPAN. NR 10 TC 7 Z9 7 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 543 EP 544 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800138 ER PT J AU MESSENGER, S CLEMETT, SJ KELLER, LP THOMAS, KL CHILLIER, XDF ZARE, RN AF MESSENGER, S CLEMETT, SJ KELLER, LP THOMAS, KL CHILLIER, XDF ZARE, RN TI CHEMICAL AND MINERALOGICAL STUDIES OF AN EXTREMELY DEUTERIUM-RICH IDP SO METEORITICS LA English DT Meeting Abstract ID INTERPLANETARY DUST PARTICLES C1 WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130. STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. MVA INC,NORCROSS,GA 30093. NASA,LOCKHEED JOHNSON SPACE CTR,HOUSTON,TX 77058. RI Zare, Richard/A-8410-2009 NR 5 TC 27 Z9 27 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 546 EP 547 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800144 ER PT J AU MIKOUCHI, T MIYAMOTO, M MCKAY, GA AF MIKOUCHI, T MIYAMOTO, M MCKAY, GA TI MINERALOGICAL COMPARISON OF OLIVINE XENOCRYSTS IN ANGRITES LEWIS-CLIFF-87051 AND ASUKA-881371 SO METEORITICS LA English DT Meeting Abstract C1 UNIV TOKYO,GRAD SCH SCI,INST MINERAL,TOKYO 113,JAPAN. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 2 Z9 2 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 549 EP 549 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800149 ER PT J AU NYQUIST, LE SHIH, CY WIESMANN, H BROWNLEE, DE XUE, S HALL, GS HERZOG, GF AF NYQUIST, LE SHIH, CY WIESMANN, H BROWNLEE, DE XUE, S HALL, GS HERZOG, GF TI CHROMIUM, NICKEL, AND IRON IN DEEP-SEA SPHERES SO METEORITICS LA English DT Meeting Abstract ID SPHERULES C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED MARTIN,HOUSTON,TX 77258. RUTGERS STATE UNIV,DEPT CHEM,NEW BRUNSWICK,NJ 08903. UNIV WASHINGTON,DEPT ASTRON,SEATTLE,WA 98105. NR 11 TC 5 Z9 5 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 558 EP 559 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800166 ER PT J AU RAO, MN GARRISON, DH BOGARD, DD PALMA, RL DREIBUS, G AF RAO, MN GARRISON, DH BOGARD, DD PALMA, RL DREIBUS, G TI ENHANCED SCR PROTON FLUX FROM THE EARLY SUN, REVISITED SO METEORITICS LA English DT Meeting Abstract C1 SAM HOUSTON STATE UNIV,HUNTSVILLE,AL. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. MAX PLANCK INST,MAINZ,GERMANY. NR 6 TC 2 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 564 EP 564 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800180 ER PT J AU ROMANEK, CS THOMAS, KL GIBSON, EK MCKAY, DS SOCKI, RA AF ROMANEK, CS THOMAS, KL GIBSON, EK MCKAY, DS SOCKI, RA TI CARBON-BEARING AND SULFUR-BEARING MINERALS IN THE MARTIAN METEORITE ALLAN-HILLS-84001 SO METEORITICS LA English DT Meeting Abstract ID CHEMISTRY C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NR 7 TC 4 Z9 4 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 567 EP 568 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800186 ER PT J AU SCOTT, ERD KROT, AN ZOLENSKY, ME AF SCOTT, ERD KROT, AN ZOLENSKY, ME TI SECONDARY MINERALIZATION OF COMPONENTS IN CV3 CHONDRITES - NEBULAR AND ASTEROIDAL MODELS SO METEORITICS LA English DT Meeting Abstract ID ALLENDE METEORITE; INCLUSIONS; ORIGIN C1 UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 14 TC 3 Z9 3 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 576 EP 576 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800202 ER PT J AU SOCKI, RA GIBSON, EK ROMANEK, CS AF SOCKI, RA GIBSON, EK ROMANEK, CS TI STABLE-ISOTOPE ENRICHMENT OF CARBONATE FROM THE MARTIAN METEORITE ALLAN-HILLS-84001 - TEST OF A HYPOTHESIS AT WRIGHT VALLEY, ANTARCTICA SO METEORITICS LA English DT Meeting Abstract ID CALCITE C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NR 10 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 580 EP 581 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800212 ER PT J AU STRAIT, MM THOMAS, KL MCKAY, DS AF STRAIT, MM THOMAS, KL MCKAY, DS TI POROSITY OF AN ANHYDROUS CHONDRITIC INTERPLANETARY DUST PARTICLE SO METEORITICS LA English DT Meeting Abstract ID MICROMETEORITES C1 ALMA COLL,ALMA,MI 48801. LOCKHEED MARTIN,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 583 EP 584 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800218 ER PT J AU THOMAS, KL KELLER, LP MCKAY, DS AF THOMAS, KL KELLER, LP MCKAY, DS TI A COMPREHENSIVE STUDY OF MAJOR-ELEMENT, MINOR-ELEMENT, AND LIGHT-ELEMENT ABUNDANCES IN OVER 100 INTERPLANETARY DUST PARTICLES SO METEORITICS LA English DT Meeting Abstract C1 LOCKHEED MARTIN,HOUSTON,TX 77058. MVA INC,NORCROSS,GA 30093. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RI Zare, Richard/A-8410-2009 NR 9 TC 9 Z9 9 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 587 EP 588 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800225 ER PT J AU THOMAS, KL CLEMETT, SJ ROMANEK, CS MACHELING, CR GIBSON, EK MCKAY, DS SCORE, R ZARE, RN AF THOMAS, KL CLEMETT, SJ ROMANEK, CS MACHELING, CR GIBSON, EK MCKAY, DS SCORE, R ZARE, RN TI POLYCYCLIC AROMATIC-HYDROCARBONS IN THE MARTIAN (SNC) METEORITE ALLAN-HILLS-84001 - HYDROCARBONS FROM MARS, TERRESTRIAL CONTAMINANTS, OR BOTH SO METEORITICS LA English DT Meeting Abstract C1 LOCKHEED MARTIN,HOUSTON,TX 77058. STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RI Zare, Richard/A-8410-2009 NR 6 TC 9 Z9 9 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 587 EP 587 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800224 ER PT J AU TROMBKA, JI BOYNTON, WV BRUCKNER, J SQUYRES, SW CLARK, PE EVANS, LG FLOYD, SR STARR, R FIORE, E GOLD, R GOLDSTEN, J MCNUTT, R AF TROMBKA, JI BOYNTON, WV BRUCKNER, J SQUYRES, SW CLARK, PE EVANS, LG FLOYD, SR STARR, R FIORE, E GOLD, R GOLDSTEN, J MCNUTT, R TI OBSERVATION OF 433-EROS WITH THE X-RAY GAMMA-RAY REMOTE-SENSING SPECTROMETER ON THE NEAR MISSION SO METEORITICS LA English DT Meeting Abstract C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV ARIZONA,TUCSON,AZ. MAX PLANCK INST CHEM,W-6500 MAINZ,GERMANY. CORNELL UNIV,ITHACA,NY. CATHOLIC UNIV AMER,WASHINGTON,DC 20064. COMP SCI CORP,LANHAM,MD. JOHNS HOPKINS UNIV,APPL PHYS LAB,BALTIMORE,MD 21218. RI McNutt, Ralph/E-8006-2010 OI McNutt, Ralph/0000-0002-4722-9166 NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 589 EP 590 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800229 ER PT J AU WASILEWSKI, PJ DICKINSON, TL AF WASILEWSKI, PJ DICKINSON, TL TI INTERPRETATION OF METEORITE MAGNETIC RECORDS NEEDS A PARADIGM SHIFT SO METEORITICS LA English DT Meeting Abstract C1 NASA,GODDARD SPACE FLIGHT CTR,USRA,GREENBELT,MD 20771. NR 4 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 594 EP 594 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800239 ER PT J AU WEISBERG, MK ZOLENSKY, ME PRINZ, M AF WEISBERG, MK ZOLENSKY, ME PRINZ, M TI FAYALITIC OLIVINE IN MATRIX OF THE KRYMKA LL3.1 CHONDRITE SO METEORITICS LA English DT Meeting Abstract ID TYPE-3 ORDINARY CHONDRITES; ORIGIN C1 AMER MUSEUM NAT HIST,DEPT EARTH & PLANETARY SCI,NEW YORK,NY 10024. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 597 EP 597 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800245 ER PT J AU ZOLENSKY, ME AF ZOLENSKY, ME TI CYCLICAL REGOLITH PROCESSES ON HYDROUS ASTEROIDS SO METEORITICS LA English DT Meeting Abstract ID CHONDRITES C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV EARTH SCI & SOLAR SYST EXPLORAT,HOUSTON,TX 77058. NR 6 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD SEP PY 1995 VL 30 IS 5 BP 606 EP 607 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RR518 UT WOS:A1995RR51800264 ER PT J AU KORANYI, DM GREEN, DA WARNER, PJ WALDRAM, EM PALMER, DM AF KORANYI, DM GREEN, DA WARNER, PJ WALDRAM, EM PALMER, DM TI SEARCH FOR A RADIO COUNTERPART TO THE GAMMA-RAY BURST GRB-940301 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Letter DE RADIATION MECHANISMS, NONTHERMAL; GAMMA-RAYS, BURSTS; RADIO CONTINUUM, GENERAL AB Observations of the field of the gamma-ray burst of 1994 March 1 (GRB 940301) at 151 MHz using the Cambridge Low Frequency Synthesis Telescope (CLFST) are presented. The field of this GRB was observed on six occasions from 1 to 36 d after the burst with a resolution of about 1 arcmin, and the results were compared with those from archival observations of the same field made in 1992 January. No significant variations were found for the sources in the field at a (2 sigma) level of about 80 mJy. The field of this burst was also observed in a non-imaging mode for six hours starting only one hour after the burst, to search for radio transients. No unusual radio 'spikes' were seen during this period, at the level of 200 Jy in the hour after the burst. C1 MULLARD RADIO ASTRON OBSERV, CAVENDISH LAB, CAMBRIDGE CB3 0HE, ENGLAND. UNIV SPACE RES ASSOC, NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Green, David/E-9609-2010 OI Green, David/0000-0003-3189-9998 NR 17 TC 15 Z9 15 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD SEP 1 PY 1995 VL 276 IS 1 BP L13 EP L17 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RR269 UT WOS:A1995RR26900004 ER PT J AU MECHOSO, CR ROBERTSON, AW BARTH, N DAVEY, MK DELECLUSE, P GENT, PR INESON, S KIRTMAN, B LATIF, M LETREUT, H NAGAI, T NEELIN, JD PHILANDER, SGH POLCHER, J SCHOPF, PS STOCKDALE, T SUAREZ, MJ TERRAY, L THUAL, O TRIBBIA, JJ AF MECHOSO, CR ROBERTSON, AW BARTH, N DAVEY, MK DELECLUSE, P GENT, PR INESON, S KIRTMAN, B LATIF, M LETREUT, H NAGAI, T NEELIN, JD PHILANDER, SGH POLCHER, J SCHOPF, PS STOCKDALE, T SUAREZ, MJ TERRAY, L THUAL, O TRIBBIA, JJ TI THE SEASONAL CYCLE OVER THE TROPICAL PACIFIC IN COUPLED OCEAN-ATMOSPHERE GENERAL-CIRCULATION MODELS SO MONTHLY WEATHER REVIEW LA English DT Article ID NINO SOUTHERN OSCILLATION; SEA-SURFACE TEMPERATURE; EL-NINO; VARIABILITY; SIMULATION; ENSO AB The seasonal cycle over the tropical Pacific simulated by 11 coupled ocean-atmosphere general circulation models (GCMs) is examined. Each model consists of a high-resolution ocean GCM of either the tropical Pacific or near-global oceans coupled to a moderate- or high-resolution atmospheric GCM, without the use of flux correction. The seasonal behavior of sea surface temperature (SST) and eastern Pacific rainfall is presented for each model. The results show that current state-of-the-art coupled GCMs share important successes and troublesome systematic errors. All 11 models are able to simulate the mean zonal gradient in SST at the equator over the central Pacific. The simulated equatorial cold tongue generally tends to be too strong, too narrow, and extend too far west. SSTs are generally too warm in a broad region west of Peru and in a band near 10 degrees S. This is accompanied in some models by a double intertropical convergence zone (ITCZ) straddling the equator over the eastern Pacific, and in others by an ITCZ that migrates across the equator with the seasons; neither behavior is realistic. There is considerable spread in the simulated seasonal cycles of equatorial SST in the eastern Pacific. Some simulations do capture the annual harmonic quite realistically, although the seasonal cold tongue tends to appear prematurely. Others overestimate the amplitude of the semiannual harmonic. Nonetheless, the results constitute a marked improvement over the simulations of only a few years ago when serious climate drift was still widespread and simulated zonal gradients of SST along the equator were often very weak. C1 UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,LOS ANGELES,CA 90095. SCRIPPS INST OCEANOG,LA JOLLA,CA. METEOROL OFF,HADLEY CTR CLIMATE PREDICT & RES,BRACKNELL,BERKS,ENGLAND. UNIV PARIS 06,LODYC,PARIS,FRANCE. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. CTR OCEAN LAND ATMOSPHERE STUDIES,CALVERTON,MD. MAX PLANCK INST METEOROL,HAMBURG,GERMANY. METEOROL DYNAM LAB,CNRS,PARIS,FRANCE. TOKYO INST TECHNOL,TOKYO 152,JAPAN. GEOPHYS FLUID DYNAM LAB,PRINCETON,NJ. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. EUROPEAN CTR MEDIUM RANGE WEATHER FORECASTS,READING RG2 9AX,BERKS,ENGLAND. CERFACS,F-31057 TOULOUSE,FRANCE. RI Neelin, J. David/H-4337-2011; THUAL, Olivier/D-5739-2014; Latif, Mojib/C-2428-2016; Robertson, Andrew/H-7138-2015; Terray, Laurent/B-8056-2008 OI THUAL, Olivier/0000-0002-1777-9415; Latif, Mojib/0000-0003-1079-5604; Terray, Laurent/0000-0001-5512-7074 NR 42 TC 361 Z9 380 U1 5 U2 35 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1995 VL 123 IS 9 BP 2825 EP 2838 DI 10.1175/1520-0493(1995)123<2825:TSCOTT>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RR513 UT WOS:A1995RR51300014 ER PT J AU SCHOPF, PS LOUGHE, A AF SCHOPF, PS LOUGHE, A TI A REDUCED-GRAVITY ISOPYCNIC OCEAN MODEL - HINDCASTS OF EL-NINO SO MONTHLY WEATHER REVIEW LA English DT Article ID COORDINATE MODEL; CIRCULATION MODEL; ATLANTIC; NORTH AB A global isopycnal ocean model is presented for the study of interannual to interdecadal variability in the global ocean. The model treats the primitive equations on a sphere with a generalized vertical coordinate. This coordinate is designed to represent a turbulent well-mixed surface layer and nearly isopycnal deeper layers. Disappearing isopycnics are treated through the quasi-isopycnal technique, in which the coordinate separates from the isopycnic in order to maintain a minimum layer thickness. A reduced gravity treatment is made,with the deepest interface at a mean depth of 2300 m. Coastal topography is represented, but the reduced gravity treatment precludes the use of variable bottom depth. The model is used for hindcast studies of El Nino during the decade from 1982 through 1991 using a combination of climatological wind forcing and wind anomalies derived from various sources. In order to carry out the hindcast experiments, a technique is developed for constructing a mean climatological surface heat flux using the model, climatological wind forcing, and climatological surface temperatures. In the hindcast runs, the climatological winds and heat flux are augmented by the wind anomalies and a weak damping of surface temperature anomalies. A series of tests compares different data products for the wind anomalies. The first product is obtained from the Florida State University (FSU) wind analysis. The second and third wind products are obtained from global climate GCM simulations run over observed sea surface temperatures (SST). Although the wind products appear quite similar, the model results show large differences in hindcast skill, reflecting the fact that subtle features of the winds can have large impacts on ocean simulations and can be seen as a primary cause of wide differences in coupled GCM performance. The model maintains a sharp thermocline and a strong equatorial undercurrent in the center of the ocean basin. The heat flux needed to keep the model near the observed temperatures appears consistent with observational studies of the mean heat flux. When measured in terms of the skill in simulating the Nino-3 SST, the NASA Coupled Climate Dynamics Group (CCDG) model and FSU wind products provide the highest skill. C1 GEN SCI CORP,LAUREL,MD. RP SCHOPF, PS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,COUPLED CLIMATE DYNAM GRP,GREENBELT,MD 20771, USA. NR 25 TC 90 Z9 90 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1995 VL 123 IS 9 BP 2839 EP 2863 DI 10.1175/1520-0493(1995)123<2839:ARGIOM>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RR513 UT WOS:A1995RR51300015 ER PT J AU MURTUGUDDE, R CANE, M PRASAD, V AF MURTUGUDDE, R CANE, M PRASAD, V TI A REDUCED-GRAVITY, PRIMITIVE EQUATION, ISOPYCNIC OCEAN GCM - FORMULATION AND SIMULATIONS SO MONTHLY WEATHER REVIEW LA English DT Article ID SEA-SURFACE TEMPERATURE; GENERAL-CIRCULATION MODEL; EQUATORIAL ATLANTIC-OCEAN; FLUX-CORRECTED TRANSPORT; TROPICAL INDIAN-OCEAN; MIXED-LAYER; COORDINATE MODEL; PACIFIC-OCEAN; SEASONAL CYCLE; VERTICAL COORDINATE AB A reduced gravity, primitive equation, ocean GCM with an isopycnal vertical coordinate is developed. A ''buffer'' layer is introduced to allow the mixed layer to detrain mass at arbitrary densities without the coordinate drift or the heat loss suffered by other isopycnal models. The diapycnal velocity is derived from the thermodynamic equation. Negative layers are removed by a heat- and mass-conserving convective adjustment scheme. The model formulation on a beta plane employs an A grid and allows irregular coastlines and local grid stretching. Simulations with climatological winds and surface heat fluxes based on observed sea surface temperatures. (SSTs) are presented for the Atlantic, the Pacific, and the Indian Oceans, The surface mixed layer is modeled as a constant depth layer, and salinity effects are neglected in this version. The surface heat flux parameterization used here leads to errors in model SSTs, which are reasonable in the Tropics but are higher in the western boundary current regions. The seasonal dependence of the currents compare reasonably well with the available observations and other model results, though there are differences in the amplitudes of the currents, The model thermocline reproduces the observed slopes, troughs, and ridges in the Tropics. Neglecting salinity effects and lack of a variable depth mixed layer affect the model simulation of the thermocline at higher latitudes. The cold tongue in the eastern Pacific is also affected by the assumption of a constant-depth mixed layer, but the warm pod in the west and the zonal slope of the thermocline correspond well with the observations. The Gulf Stream and the Kuroshio have reasonable current speeds but separate slightly earlier than observed, in contrast to most models that separate late. Seasonal reversal of the Somali Current in the Indian Ocean and the South Equatorial Current in the Pacific Ocean are reproduced, and the Equatorial Undercurrent is stronger than in most models with comparable grid resolution. Efforts underway to improve model performance are listed along the way. C1 COLUMBIA UNIV, LAMONT DOHERTY EARTH OBSERV, PALISADES, NY 10964 USA. SUNY STONY BROOK, DEPT MECH ENGN, STONY BROOK, NY 11794 USA. RP NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, CODE 971, GREENBELT, MD 20771 USA. NR 85 TC 14 Z9 14 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1995 VL 123 IS 9 BP 2864 EP 2887 DI 10.1175/1520-0493(1995)123<2864:ARGPEI>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RR513 UT WOS:A1995RR51300016 ER PT J AU Austin, RE Cook, SA AF Austin, RE Cook, SA TI SSTO rockets: Streamlining access to space SO NOUVELLE REVUE AERONAUTIQUE ASTRONAUTIQUE LA French DT Article AB The next generation of U.S. launch vehicles must dramatically lower the cost of space access. Today's launch systems consume such enormous quantities of the space program's funding, talent, and infrastructure that little is left for the bold endeavors that advance technology and inspire the imagination. lowering space transportation costs would spur U.S, competitiveness and industrial might. Today's launch systems, besides being too costly, lack sufficient reliability, safety, and operability. Increasingly, they are losing market share to international competition. For the U.S. to maintain leadership in the human exploration and commercial utilization of space, the first order of business must be to develop low-cost, reliable transportation to Earth orbit. The launch business is at a crossroads similar to that faced by the fledgling airline industry in the early 1930s. An evolutionary technical leap analogous to the DC-3, coupled with a revolutionary cultural shift, must occur for space access to become truly routine. NASA's Access to Space Study recommended development of a fully reusable single-stage-to-orbit rocket vehicle as an agency goal. An all-rocket SSTO vehicle appears to be the best blend of near-term achievable Technology for low-cost routine space access after the turn of the century This is an evolutionary path that will rely on 25 years of aerospace experience to mature and demonstrate several advanced technologies needed to create a cost-effective, reusable new launch vehicle. It is supported by the recently released National Space Transportation Policy. A fully reusable single stage-to-orbit rocket would slash launch costs by reducing the huge infrastructure needed for today's systems. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,REUSABLE LAUNCH VEHICLE TECHNOL PROJECT,HUNTSVILLE,AL 35812. RP Austin, RE (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ADV TRANSPORTAT TECHNOL OFF,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU DUNOD PI MONTROUGE CEDEX PA 15 RUE GOSSIN, 92543 MONTROUGE CEDEX, FRANCE SN 1247-5793 J9 NOUV REV AERONAUT AS JI Nouv. Rev. Aeronaut. Astronaut. PD SEP-OCT PY 1995 IS 5 BP 11 EP 16 PG 6 WC Engineering, Aerospace SC Engineering GA TK339 UT WOS:A1995TK33900003 ER PT J AU CHO, CS KIM, JC YOON, TH NAM, KG PARK, UY LIU, HK AF CHO, CS KIM, JC YOON, TH NAM, KG PARK, UY LIU, HK TI OPTOELECTRONIC IMPLEMENTATION OF A DIFFUSION NEURAL-NETWORK FOR EDGE-DETECTION SO OPTICS LETTERS LA English DT Article AB We investigate the feasibility of an optoelectronic edge detection system, using a diffusion neural network. The diffusion neural network performs the Gaussian operation efficiently by means of the diffusion process. We apply this in producing the difference-of-two-Gaussians function, which can detect the intensity changes of This system is composed of a spatial light modulator, a two-dimensional image sensor array, and a The processing of the system can be done at a rate of 30 frames/s, making it potentially applicable to systems that require edge detection of an image in real time. (C) 1995 Optical Society of America C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP CHO, CS (reprint author), PUSAN NATL UNIV,DEPT ELECTR ENGN,PUSAN 609735,SOUTH KOREA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD SEP 1 PY 1995 VL 20 IS 17 BP 1806 EP 1808 PG 3 WC Optics SC Optics GA RQ726 UT WOS:A1995RQ72600022 ER PT J AU DOMINIK, C TIELENS, AGGM AF DOMINIK, C TIELENS, AGGM TI RESISTANCE TO ROLLING IN THE ADHESIVE CONTACT OF 2 ELASTIC SPHERES SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID SURFACE-ENERGY; FRACTURE; SOLIDS AB For the stability of agglomerates of micron sized particles it is of considerable importance to study the effects of tangential forces on the contact of two particles. If the particles can slide or roll easily over each other, fractal structures of these agglomerates will not be stable. We use the description of contact forces by Johnson, Kendall and Roberts, along with arguments based on the atomic structure of the surfaces in contact, in order to calculate the resistance to rolling in such a contact. II is shown that the contact reacts elastically to torque forces up to a critical bending angle. Beyond that, irreversible rolling occurs. In the elastic regime, the moment opposing the attempt to roll is proportional to the bending angle and to the pull-off force P-c. Young's modulus of the involved materials has hardly any influence on the results. We show that agglomerates of sub-micron sized particles will in general be quite rigid and even long chains of particles cannot be bent easily. For very small particles, the contact will rather break than allow for rolling. We further discuss dynamic properties such as the possibility of vibrations in this degree of freedom and the typical amount of rolling during a collision of two particles. RP DOMINIK, C (reprint author), NASA,AMES RES CTR,MAIL STOP 245-3,MOFFETT FIELD,CA 94035, USA. NR 22 TC 113 Z9 114 U1 1 U2 16 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD SEP PY 1995 VL 72 IS 3 BP 783 EP 803 PG 21 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA TE280 UT WOS:A1995TE28000017 ER PT J AU BHALLA, CP GRABBE, SR BHATIA, AK AF BHALLA, CP GRABBE, SR BHATIA, AK TI DIFFERENTIAL CROSS-SECTIONS FOR THE ELECTRON-IMPACT EXCITATION OF HYDROGENLIKE CARBON SO PHYSICAL REVIEW A LA English DT Article ID HE-LIKE IONS; ANGULAR-DISTRIBUTION; RESONANCE TRANSITIONS; COLLISION STRENGTHS; AUGER ELECTRONS; ENERGY-LOSS; STATES; PROGRAM; ATOM; C-4+ AB We report on a study of total and differential excitation cross sections for the electron-impact excitation of hydrogenlike carbon for the transitions 1s(2)S --> 2s(2)S and 2p(2)P. These calculations have been performed for electron-impact energies ranging from 28.2 to 29.5 Ry using the close-coupling R-matrix method. This energy region has been chosen because in addition to the direct excitation of 2s and 2p, there is a sizable contribution to the excitation cross section from the doubly excited two-electron states (3l3l'), which decay predominantly to n = 2 via autoionization. Differential cross sections both for the direct nonresonant channel and in the vicinity of several autoionizing resonant states are presented. The differential cross sections in the vicinity of the autoionizing resonant states are shown to be very rich in structure. We discuss the relevance of these calculations to a recent experiment that measured the electron emission spectra for the collision of C5++H-2. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP BHALLA, CP (reprint author), KANSAS STATE UNIV AGR & APPL SCI,DEPT PHYS,JR MACDONALD LAB,MANHATTAN,KS 66506, USA. NR 46 TC 12 Z9 12 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD SEP PY 1995 VL 52 IS 3 BP 2109 EP 2119 DI 10.1103/PhysRevA.52.2109 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA RU159 UT WOS:A1995RU15900039 ER PT J AU PANDA, J ADAMOVSKY, G AF PANDA, J ADAMOVSKY, G TI LASER-LIGHT SCATTERING BY SHOCK-WAVES SO PHYSICS OF FLUIDS LA English DT Article AB Scattering of coherent light as it propagates parallel to a shock wave, formed in front of a bluff cylindrical body placed in a supersonic stream, is studied experimentally and numerically. Two incident optical fields are considered. First, a large diameter collimated beam is allowed to pass through the shock containing flow. The light intensity distribution in the resultant shadowgraph image, measured by a low light CCD camera, shows well-defined fringes upstream and downstream of the shadow cast by the shock. In the second situation, a narrow laser beam is brought to a grazing incidence on the shock and the scattered light, which appears as a diverging sheet from the point of interaction, is visualized and measured on a screen placed normal to the laser path. Experiments are conducted on shocks formed at various free-stream Mach numbers, M, and total pressures, P-0. It is found that the widths of the shock shadows in a shadowgraph image become independent of M and P-0 when plotted against the jump in the refractive index, Delta n, created across the shock. The total scattered light measured from the narrow laser beam and shock interaction also follows the same trend. In the numerical part of the study, the shock is assumed to be a ''phase object,'' which introduces phase difference between the upstream and downstream propagating parts of the light disturbances. For a given shape and Delta n of the bow shock the phase and amplitude modulations are first calculated by ray tracing. The wave front is then propagated to the screen using the Fresnel diffraction equation. The calculated intensity distribution, for both of the incident optical fields, shows good agreement with the experimental data. (C) 1995 American Institute of Physics. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP PANDA, J (reprint author), UNIV TOLEDO,2801 W BANCROFT ST,TOLEDO,OH 43606, USA. NR 16 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD SEP PY 1995 VL 7 IS 9 BP 2271 EP 2279 DI 10.1063/1.868475 PG 9 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RR501 UT WOS:A1995RR50100020 ER PT J AU REED, HL BRENNER, MP SHI, XD EGGERS, J NAGEL, SR BUCHHOLZ, J SIGURDSON, L PECK, B BUDZINSKI, JM BENJAMIN, RF DEPEUVEDIC, JM JACOBS, JW GOGINENI, SP WHITAKER, MM GOSS, LP ROQUEMORE, WM HOROWITZ, J WOO, MJ GREBER, I KOUMOUTSAKOS, P LEONARD, A METCALFE, G SHINBROT, T MCCARTHY, JJ OTTINO, JM MILLER, GD WILLIAMSON, CHK PETITJEANS, P WESFREID, JE RAMBOD, E GHARIB, M AF REED, HL BRENNER, MP SHI, XD EGGERS, J NAGEL, SR BUCHHOLZ, J SIGURDSON, L PECK, B BUDZINSKI, JM BENJAMIN, RF DEPEUVEDIC, JM JACOBS, JW GOGINENI, SP WHITAKER, MM GOSS, LP ROQUEMORE, WM HOROWITZ, J WOO, MJ GREBER, I KOUMOUTSAKOS, P LEONARD, A METCALFE, G SHINBROT, T MCCARTHY, JJ OTTINO, JM MILLER, GD WILLIAMSON, CHK PETITJEANS, P WESFREID, JE RAMBOD, E GHARIB, M TI GALLERY OF FLUID MOTION SO PHYSICS OF FLUIDS LA English DT Editorial Material AB This article displays winning photographs from the twelfth Annual Fluid Mechanics Photo Contest held at the November 1994 meeting of the American Physical Society, Division of Fluid Dynamics, Atlanta, Georgia. C1 MIT,CAMBRIDGE,MA 02139. UNIV ALBERTA,EDMONTON,AB,CANADA. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV ARIZONA,TUCSON,AZ 85721. SYST RES LABS INC,DAYTON,OH. NASA,LEWIS RES CTR,CLEVELAND,OH. CASE WESTERN RESERVE UNIV,CLEVELAND,OH. RP REED, HL (reprint author), ARIZONA STATE UNIV,AEROSP RES CTR,TEMPE,AZ 85287, USA. RI Metcalfe, Guy/C-1332-2008; Ottino, Julio/B-6682-2009; McCarthy, Joseph/K-6925-2012; Koumoutsakos, Petros/A-2846-2008; Jacobs, Jeffrey/B-1339-2013 OI Metcalfe, Guy/0000-0003-4679-8663; McCarthy, Joseph/0000-0002-2841-3128; Koumoutsakos, Petros/0000-0001-8337-2122; Jacobs, Jeffrey/0000-0003-0193-7105 NR 10 TC 0 Z9 0 U1 2 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD SEP PY 1995 VL 7 IS 9 BP S1 EP S12 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RR501 UT WOS:A1995RR50100001 ER PT J AU TRALLI, DM ITA, JJ AF TRALLI, DM ITA, JJ TI REGIONALIZED TEMPERATURE-VARIATIONS IN THE UPPER 400 KM OF THE EARTH MANTLE SO PHYSICS OF THE EARTH AND PLANETARY INTERIORS LA English DT Article; Proceedings Paper CT 4th International Symposium of the International-Union-of-Geodesy-and-Geophysics (IUGG) Union-Committee-for-Study-of-the-Earths-Deep-Interior (SEDI) CY AUG 07-12, 1994 CL WHISTLER MOUNTAIN, CANADA SP Int Union Geodesy & Geophys, Union Comm Study Earths Deep Interior ID TRAVEL-TIMES; LOCATION AB Tectonically regionalized variations in the temperature of the upper 400 km of the Earth's mantle are estimated from analysis of global seismic travel-time data cataloged by the International Seismological Centre (ISC). Seismic parameter profiles are determined from estimates of P and S velocities obtained by tau inversion. Summary phase diagrams for the olivine and pyroxene-garnet subsystems are constructed in conjunction with a thermodynamic potential formulation that allows self-consistent determination of density, bulk modulus and adiabats throughout the pressure and temperature regimes of the mantle. Perturbations in estimated seismic parameters are expressed in terms of variations in temperature using the model temperature derivatives of the bulk modulus and density at a given temperature and pressure. Confidence bounds on the velocity estimates are used to place corresponding bounds on the constructed seismic parameters. A simple differential relationship is solved iteratively to obtain a temperature variation for a given variation in seismic parameter. This approach allows the estimation of a range of seismically determined temperature variations by employing a given compositional model. Results indicate that whereas the P and S velocity variations in the upper mantle are consistent with the tectonic regionalization, variations in V-p/V-s ratios are irregular. This leads to unstable estimates of the seismic parameters and thus estimates of mean temperature anomalies, typically within 600 degrees C of the weighted mean, that are inconsistent with the regionalized seismic data. A comparison of two compositional models is used to show the trade-off with estimated temperature variations. A refined regionalization and analysis of a larger ISC data set are suggested to stabilize the S velocity inversion, reduce statistical uncertainties on the seismic parameters, and thus improve constraints on estimated temperature variations. C1 CALTECH,SEISMOL LAB,PASADENA,CA 91125. RP TRALLI, DM (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 13 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-9201 J9 PHYS EARTH PLANET IN JI Phys. Earth Planet. Inter. PD SEP PY 1995 VL 91 IS 1-3 BP 177 EP 186 DI 10.1016/0031-9201(95)03046-Y PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RU596 UT WOS:A1995RU59600015 ER PT J AU BROWN, AH CHAPMAN, DK JOHNSSON, A HEATHCOTE, D AF BROWN, AH CHAPMAN, DK JOHNSSON, A HEATHCOTE, D TI GRAVITROPIC RESPONSES OF THE AVENA-COLEOPTILE IN-SPACE AND ON CLINOSTATS .1. GRAVITROPIC RESPONSE THRESHOLDS SO PHYSIOLOGIA PLANTARUM LA English DT Article DE AVENA SATIVA; GRAVITROPISM; IML-1; MICROGRAVITY; OAT; RECIPROCITY; SPACE AB We conducted a series of gravitropic experiments on Avena coleoptiles in the weightlessness environment of Spacelab. The purpose was to test the threshold stimulus, reciprocity rule and autotropic reactions to a range of g-force stimulations of different intensities and durations The tests avoided the potentially complicating effects of earth's gravity and the interference from clinostat ambiguities. Using slow-speed centrifuges, coleoptiles received transversal accelerations in the hypogravity range between 0.1 and 1.0 g over periods that ranged from 2 to 130 min. All responses that occurred in weightlessness were compared to clinostat experiments on earth using the same apparatus. Characteristic gravitropistic response patterns of Avena were not substantially different from those observed in ground-based experiments. Gravitropic presentation times were extrapolated. The threshold at 1.0 g was less than 1 min (shortest stimulation time 2 min), in agreement with values obtained on the ground. The least stimulus tested, 0.1 g for 130 min, produced a significant response. Therefore the absolute threshold for a gravitropic response is less than 0.1 g. C1 UNIV TRONDHEIM,AVH,DEPT PHYS,N-7055 DRAGVOLL,NORWAY. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV PENN,DEPT BIOL,GODDARD LABS,PHILADELPHIA,PA 19104. GEN DYNAM CORP,KENNEDY SPACE CTR,FL 32899. NR 15 TC 22 Z9 22 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0031-9317 J9 PHYSIOL PLANTARUM JI Physiol. Plant. PD SEP PY 1995 VL 95 IS 1 BP 27 EP 33 DI 10.1034/j.1399-3054.1995.950104.x PG 7 WC Plant Sciences SC Plant Sciences GA TD520 UT WOS:A1995TD52000004 PM 11539922 ER PT J AU JOHNSSON, A BROWN, AH CHAPMAN, DK HEATHCOTE, D KARLSSON, C AF JOHNSSON, A BROWN, AH CHAPMAN, DK HEATHCOTE, D KARLSSON, C TI GRAVITROPIC RESPONSES OF THE AVENA-COLEOPTILE IN-SPACE AND ON CLINOSTATS .2. IS RECIPROCITY VALID SO PHYSIOLOGIA PLANTARUM LA English DT Article DE AVENA SALIVA; GRAVITROPISM; IML-1; MICROGRAVITY; OAT; RECIPROCITY; SPACE AB Experiments were undertaken to determine if the reciprocity rule is valid for gravitropic responses of oat coleoptiles in the acceleration region below 1 g. The rule predicts that the gravitropic response should be proportional to the product of the applied acceleration and the stimulation time. Seedlings were cultivated on 1 g centrifuges and transferred to test centrifuges to apply a transverse g-stimulation. Since responses occurred in microgravity, the uncertainties about the validity of clinostat simulation of weightlessness was avoided. Plants at two stages of coleoptile development were tested. Plant responses were obtained using time-lapse video recordings that were analyzed after the flight. Stimulus intensities and durations were varied and ranged from 0.1 to 1.0 g and from 2 to 130 min, respectively. For threshold g-doses the reciprocity rule was obeyed The threshold dose was of the order of 55 g s and 120 g a, respectively, for two groups of plants investigated. Reciprocity was studied also at bending responses which are from just above the detectable level to about 10 degrees. The validity of the rule could not be confirmed for higher g-doses, chiefly because the data were more variable. It was investigated whether the uniformity of the overall response data increased when the gravitropic dose was defined as (g(m) X t), with m-values different from unity. This was not the case and the reciprocity concept is, therefore, valid also in the hypogravity region. The concept of gravitropic dose, the product of the transverse acceleration and the stimulation time, is also well-defined in the acceleration region studied. With the same hardware, tests were done on earth where responses occurred on clinostats. The results did not contradict the reciprocity rule but scatter in the data was large. C1 UNIV PENN,DEPT BIOL,PHILADELPHIA,PA 19104. GEN DYNAM CORP,DYN3,KENNEDY SPACE CTR,FL 32899. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP JOHNSSON, A (reprint author), UNIV TRONDHEIM,AVH,DEPT PHYS,N-7055 DRAGVOLL,NORWAY. NR 8 TC 9 Z9 9 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0031-9317 J9 PHYSIOL PLANTARUM JI Physiol. Plant. PD SEP PY 1995 VL 95 IS 1 BP 34 EP 38 DI 10.1034/j.1399-3054.1995.950105.x PG 5 WC Plant Sciences SC Plant Sciences GA TD520 UT WOS:A1995TD52000005 PM 11539923 ER PT J AU AGUIRRE, AA BALAZS, GH SPRAKER, TR GROSS, TS AF AGUIRRE, AA BALAZS, GH SPRAKER, TR GROSS, TS TI ADRENAL AND HEMATOLOGICAL RESPONSES TO STRESS IN JUVENILE GREEN TURTLES (CHELONIA-MYDAS) WITH AND WITHOUT FIBROPAPILLOMAS SO PHYSIOLOGICAL ZOOLOGY LA English DT Article ID LOGGERHEAD SEA TURTLE; CARETTA-CARETTA; BLOOD; DISTRESS; ANIMALS; VALUES AB This study reports baseline adrenocortical, hematological, and plasma biochemical values for clinically healthy ,juvenile green turtles from a discrete population at Kaneohe Bay, island of Oahu, Hawaii. Using a general linear modeling program, we compared mean values for these parameters with mean values of a group afflicted with green turtle fibropapillomas (GTFP). Turtles of similar size classes from both groups were collected under the same conditions in the same study area and season at the same time of the day. Corticosterone, hematological, and enzymatic responses to acute and chronic stress were characterized for each group at four different sampling periods: 0 h (within 2 min of capture), 1 h, 3-4 h, and 24 h postcapture. On the basis of the differences identified between groups and times within a group, we conclude that turtles with GTFP are chronically stressed and immunosuppressed. C1 NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. WILDLIFE PATHOL INT,FT COLLINS,CO 80525. UNIV FLORIDA,INTERDISCIPLINARY CTR BIOTECHNOL RES,GAINESVILLE,FL 32611. RP AGUIRRE, AA (reprint author), COLORADO STATE UNIV,POB 1522,FT COLLINS,CO 80522, USA. NR 42 TC 99 Z9 105 U1 3 U2 15 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0031-935X J9 PHYSIOL ZOOL JI Physiol. Zool. PD SEP-OCT PY 1995 VL 68 IS 5 BP 831 EP 854 PG 24 WC Physiology; Zoology SC Physiology; Zoology GA RV962 UT WOS:A1995RV96200007 ER PT J AU HEAP, SR BRANDT, JC RANDALL, CE CARPENTER, KG LECKRONE, DS MARAN, SP SMITH, AM BEAVER, EA BOGGESS, A EBBETS, DC GARNER, HW HUTCHINGS, KB JURA, M LINSKY, JL SAVAGE, BD CARDELLI, JA TRAFTON, LM WALTER, FM WEYMANN, RJ AKE, TB CRENSHAW, DM MALUMUTH, EM ROBINSON, RD SANDOVAL, JL SHORE, SN WAHLGREN, GM BRUHWEILER, F LINDLER, DJ GILLILAND, RL HULBERT, SJ SODERBLOM, DR AF HEAP, SR BRANDT, JC RANDALL, CE CARPENTER, KG LECKRONE, DS MARAN, SP SMITH, AM BEAVER, EA BOGGESS, A EBBETS, DC GARNER, HW HUTCHINGS, KB JURA, M LINSKY, JL SAVAGE, BD CARDELLI, JA TRAFTON, LM WALTER, FM WEYMANN, RJ AKE, TB CRENSHAW, DM MALUMUTH, EM ROBINSON, RD SANDOVAL, JL SHORE, SN WAHLGREN, GM BRUHWEILER, F LINDLER, DJ GILLILAND, RL HULBERT, SJ SODERBLOM, DR TI THE GODDARD HIGH-RESOLUTION SPECTROGRAPH - IN-ORBIT PERFORMANCE SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID HUBBLE-SPACE-TELESCOPE AB The in-orbit performance of the Goddard High-Resolution Spectrograph onboard the Hubble Space Telescope (HST) is presented. This report covers the pre-COSTAR period, when instrument performance was limited by the effects of spherical aberration of the telescope's primary mirror The digicon detectors provide a linear response to count rates spanning over six orders of magnitude, ranging from the normal background flux of 0.01 counts diode(-1) s(-1) to values larger than 10(4) counts diode(-1) s(-1). Scattered light from the first-order gratings is small and can be removed by standard background-subtraction techniques. Scattered light in the echelle mode is more complex in origin, but it also can be accurately removed. Data have been obtained over a wavelength range from below 1100 Angstrom to 3300 Angstrom, at spectral resolutions as high as R = lambda/Delta lambda = 90,000. The wavelength scale is influenced by spectrograph temperature, outgassing of the optical bench, and interaction of the magnetic field within the detector with the Earth's magnetic field. Models of these effects lead to a default wavelength scale with an accuracy better than 1 diode, corresponding to 3 km s(-1) in the echelle mode. With care, the wavelength scale can be determined to an accuracy of 0.2 diodes. Calibration of the instrument sensitivity functions is tied into the HST flux calibration through observations of spectrophotometric standard stars. The measurements of vignetting and the echelle blaze function provide relative photometric precision to about 5% or better. The effects of fixed-pattern noise have been investigated, and techniques have been devised for recognizing and removing it from the data. The ultimate signal-to-noise ratio achievable with the spectrograph is essentially limited only by counting statistics, and values approaching 1000:1 have been obtained. C1 UNIV COLORADO, ATMOSPHER & SPACE PHYS LAB, BOULDER, CO 80309 USA. UNIV CALIF SAN DIEGO, CTR ASTROPHYS & SPACE SCI, LA JOLLA, CA 92093 USA. BALL AEROSP SYST GRP, BOULDER, CO 80306 USA. DOMINION ASTROPHYS OBSERV, VICTORIA, BC V8X 4M6, CANADA. UNIV CALIF LOS ANGELES, DEPT ASTRON, LOS ANGELES, CA 90024 USA. UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. NATL INST STAND & TECHNOL, BOULDER, CO 80309 USA. UNIV WISCONSIN, DEPT ASTRON, MADISON, WI 53706 USA. UNIV TEXAS, MCDONALD OBSERV, AUSTIN, TX 78712 USA. UNIV TEXAS, DEPT ASTRON, AUSTIN, TX 78712 USA. SUNY STONY BROOK, DEPT EARTH & SPACE SCI, STONY BROOK, NY 11794 USA. CARNEGIE INST WASHINGTON OBSERV, PASADENA, CA 91101 USA. NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, ASTRON PROGRAM, GREENBELT, MD 20771 USA. SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. CATHOLIC UNIV AMER, NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP HEAP, SR (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RI heap, sara/E-2237-2012; Carpenter, Kenneth/D-4740-2012; Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 25 TC 63 Z9 63 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD SEP PY 1995 VL 107 IS 715 BP 871 EP 887 DI 10.1086/133635 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RV821 UT WOS:A1995RV82100006 ER PT J AU CALVERT, W BENSON, RF CARPENTER, DL FUNG, SF GALLAGHER, DL GREEN, JL HAINES, DM REIFF, PH REINISCH, BW SMITH, MF TAYLOR, WWL AF CALVERT, W BENSON, RF CARPENTER, DL FUNG, SF GALLAGHER, DL GREEN, JL HAINES, DM REIFF, PH REINISCH, BW SMITH, MF TAYLOR, WWL TI THE FEASIBILITY OF RADIO SOUNDING IN THE MAGNETOSPHERE SO RADIO SCIENCE LA English DT Article ID CONTINUUM RADIATION; Z-MODE; REGIONS AB A radio sounder outside the plasmasphere could provide nearly continuous remote density measurements of the magnetopause and plasmasphere, as well as other important density features elsewhere in this region. Using digital integration and tuned reception at frequencies from a few kilohertz to a few megahertz with 400-m to 500-m tip-to-tip dipole antennas and 10 W transmitter power, such a sounder would be capable of 10% density resolution and 500 to 1300 km spatial resolution in only a few minutes at distances of up to 4 R(E). By providing such detailed observations of its principal density structures, such a sounder would then clearly revolutionize magnetospheric research. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. STANFORD UNIV, STAR LAB, STANFORD, CA 94305 USA. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, HUNTSVILLE, AL 35812 USA. UNIV MASSACHUSETTS, LOWELL, MA 01854 USA. RICE UNIV, HOUSTON, TX 77251 USA. NICHOLS RES CORP, ARLINGTON, VA 22209 USA. RP CALVERT, W (reprint author), UNIV IOWA, DEPT PHYS & ASTRON, IOWA CITY, IA 52242 USA. RI Fung, Shing/F-5647-2012; Reiff, Patricia/D-2564-2014 OI Reiff, Patricia/0000-0002-8043-5682 NR 52 TC 30 Z9 30 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 EI 1944-799X J9 RADIO SCI JI Radio Sci. PD SEP-OCT PY 1995 VL 30 IS 5 BP 1577 EP 1595 DI 10.1029/95RS01731 PG 19 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA RY692 UT WOS:A1995RY69200022 ER PT J AU BROWN, CW ESAIAS, WE THMPSON, AM AF BROWN, CW ESAIAS, WE THMPSON, AM TI PREDICTING PHYTOPLANKTON COMPOSITION FROM SPACE - USING THE RATIO OF EUPHOTIC DEPTH TO MIXED-LAYER DEPTH - AN EVALUATION SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID WATERS AB A technique to remotely characterize the taxonomic composition of phytoplankton would have application in several fields of environmental study. Satellite imagery available presently and in the near future will likely not be able to accomplish this, except in unique cases, using spectral methods. As an alternative approach, we empirically evaluated a technique that uses the ratio of euphotic depth (Z(eu)) to mixed-layer depth (Z(m)) as a parameter to predict the relative abundance of three major algal groups-diatoms, dinoflagellates, and coccolithophores in the surface layer of the temperate North Atlantic and North Pacific Oceans. The ratio can be ascertained without in situ measurements; Z(eu) can be estimated from ocean color imagery, and Z(m) can be derived from hydrographic models. Diatoms were found to dominate the phytoplankton community, in terms of cell concentration, at stations possessing significantly greater values of the ratio Z(eu):Z(m) than those stations where dinoflagellates dominated This is contrary to the generally accepted view that diatoms occupy less stratified water columns than dinoflagellates. The result, which may merely reflect the data set employed and as such requires further testing could aid in classifying the phytoplankton on a regional basis. However, we conclude that the use of the ratio Z(eu):Z(m) is not likely to provide a general; nonspectral technique to characterize the taxonomic composition of phytoplankton. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RP BROWN, CW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,OCEANS & ICE BRANCH,CODE 971,GREENBELT,MD 20771, USA. RI Brown, Christopher/B-8213-2008; Thompson, Anne /C-3649-2014 OI Brown, Christopher/0000-0002-9905-6391; Thompson, Anne /0000-0002-7829-0920 NR 17 TC 6 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD SEP PY 1995 VL 53 IS 3 BP 172 EP 176 DI 10.1016/0034-4257(95)00099-M PG 5 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RV896 UT WOS:A1995RV89600005 ER PT J AU MILLER, RL CRUISE, JF AF MILLER, RL CRUISE, JF TI EFFECTS OF SUSPENDED SEDIMENTS ON CORAL GROWTH - EVIDENCE FROM REMOTE-SENSING AND HYDROLOGIC MODELING SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID CARIBBEAN REEF CORALS; MONTASTRAEA-ANNULARIS; WATER-CONTENT; RATES; PATTERNS; STRESS AB Remotely sensed images derived from several sources were combined with in situ samples to estimate suspended sediments discharged from three rivers into Mayaguez Bay, Puerto Rico. Multispectral data were acquired using the Calibrated Airborne Multispectral Scanner (CAMS) and the Landsat Thematic Mapper (TM). CAMS data were used to produce spatial maps of suspended sediment concentrations in Mayaguez Bay during low to moderate discharge for 1990-1992. Images of band cover/land use during 1975 and 1985 were generated from a supervised density slicing technique applied to a mosaicked image of digitized aerial photos and from an unsupervised classification of the TM image. A geomorphic hydrologic model was used to simulate runoff and sediment yield from the drainage basin of the Guanajibo river; because land cover within the basin did not change significantly during 1975-1985, the hydrologic model provided estimates of sediment discharged by the Guanajibo river into the bay during this time period. Growth rates of the coral Montastrea annularis of Rodiguez reef were obtained from a previous study. Annual growth rates as determined from coral banding decreased significantly (r = 0.69) with increased sediment loading to the bay (tons/year). Evidence from remote sensing and hydrologic modeling suggests that sediment reaches the reef only during episodic, high-discharge events. During low to moderate discharge, sediments, both suspended within the river plume and resuspended sediments, are restricted to the near-shore regions by the prevailing circulation. Hence, a direct relationship between river runoff and coral growth rates was established in this study. C1 LOUISIANA STATE UNIV,DEPT CIVIL & ENVIRONM ENGN,BATON ROUGE,LA 70803. RP MILLER, RL (reprint author), NASA,EARTH OBSERV RES OFF,JA20 BLDG 1100,BAY ST LOUIS,MS 39529, USA. RI kohki, sowa/D-2955-2011 NR 41 TC 40 Z9 43 U1 1 U2 11 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD SEP PY 1995 VL 53 IS 3 BP 177 EP 187 DI 10.1016/0034-4257(95)00081-B PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RV896 UT WOS:A1995RV89600006 ER PT J AU YODER, BJ PETTIGREWCROSBY, RE AF YODER, BJ PETTIGREWCROSBY, RE TI PREDICTING NITROGEN AND CHLOROPHYLL CONTENT AND CONCENTRATIONS FROM REFLECTANCE SPECTRA (400-2500 NM) AT LEAF AND CANOPY SCALES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SPECTROSCOPY; CHEMISTRY; LEAVES; LIGHT AB An experiment was designed to determine whether chlorophyll and nitrogen concentrations could be predicted from reflectance (R) spectra of fresh bigleaf maple leaves in the laboratory, and, if so, whether the predictive spectral features could be correlated with chlorophyll and nitrogen concentration or content of simple canopies of maple seedlings. The best predictors for nitrogen and chlorophyll of fresh leaves appeared with first-difference transformations of log 1/R, and the bands selected were similar to those found in other studies. Shortwave infrared bands were best predictors for nitrogen, visible bands best for chlorophyll. In the shortwave infrared region, however the absolute differences in reflectance at critical bands was extremely small, and the bands of high correlation were narrow. High spectral and radiance resolution are required to resolve these differences accurately. The best shortwave infrared bands from the leaf scale were not good predictors of chemical content or concentration at the canopy scale; variability in canopy reflectance in the shortwave infrared region was at least an order of magnitude beyond that necessary to detect signals from chemicals. The variability in first-difference log 1/R on the canopy scale was related to the arrangement of trees with respect to direct solar radiation, instrument noise, leaf fluttering, and small changes in atmospheric moisture. C1 NASA,AMES RES CTR,JOHNSON CONTROLS INC,MOFFETT FIELD,CA 94035. RP YODER, BJ (reprint author), OREGON STATE UNIV,DEPT FOREST SCI,CORVALLIS,OR 97331, USA. NR 28 TC 338 Z9 406 U1 5 U2 49 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD SEP PY 1995 VL 53 IS 3 BP 199 EP 211 DI 10.1016/0034-4257(95)00135-N PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RV896 UT WOS:A1995RV89600008 ER PT J AU YAO, XZ YANG, TF CHANGDIAZ, FR AF YAO, XZ YANG, TF CHANGDIAZ, FR TI A LASER-INDUCED FLUORESCENCE MEASUREMENT TECHNIQUE FOR OBTAINING NEUTRAL HYDROGEN DENSITIES IN PLASMAS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID BALMER-ALPHA AB The resonance fluorescence of neutral hydrogen illuminated by H-alpha radiation has been used as a technique for the spatially and temporally resolved density measurements of neutral hydrogen in high temperature plasmas, such as in the tokamak and magnetic mirror plasma fusion devices. The fluorescence signal, usually very weak and buried in the background of stray laser light and H-alpha emission, is very difficult to extract and ifs measurements are inaccurate. This paper discusses the improvement of the signal extraction using two optical path laser-induced fluorescence (LIF) methods. One optical path carries the fluorescence signal and the background (the stray laser light and H-alpha emission), whereas the other path carries only the background signal. By combining these two signals, a clean fluorescence signal can be isolated by subtracting out the background using a differential amplifier. The measurement is obtained instantaneously from these two signals which are taken simultaneously in one pulse rather than being extracted from two separate spectra taken in two sequential pulses (double pulses). This method, therefore, makes a significant improvement on the double pulse technique in terms of the accuracy of the measurement and the time resolution. Using this LIF technique the measurement of the neutral density profile in the exhaust of a tandem mirror plasma propulsion device is obtained and presented. (C) 1995 American Institute of Physics. C1 CHINESE ACAD SCI,INST PHYS,BEIJING 100080,PEOPLES R CHINA. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP YAO, XZ (reprint author), MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139, USA. NR 19 TC 2 Z9 2 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD SEP PY 1995 VL 66 IS 9 BP 4595 EP 4599 DI 10.1063/1.1145295 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA RV679 UT WOS:A1995RV67900029 ER PT J AU YANG, TF LIU, P CHANGDIAZ, FR LANDER, H CHILDS, RA BECKER, HD FAIRFAX, SA AF YANG, TF LIU, P CHANGDIAZ, FR LANDER, H CHILDS, RA BECKER, HD FAIRFAX, SA TI A DOUBLE PENDULUM PLASMA THRUST BALANCE AND THRUST MEASUREMENT AT A TANDEM MIRROR EXHAUST SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB For the purpose of measuring the plasma momentum flux in a plasma system, a highly sensitive and precision balance has been developed. It can measure a force, an impulse, or thrust as low as 0.1 mN free of mechanical noise, electrical and magnetic pickups. The double pendulum system consists sf two parallel conducting plates. One or both of the plates can be suspended by needles. The needle suspended plate (or plates) can swing freely with negligible friction because of the sharp points of the needles. When one of the plates is impacted by an impulse it will swing relatively to the fixed plate or other movable plate. The capacitance between the plates changes as a result of such a motion. The change of capacitance as a function of time is recorded as an oscillating voltage signal. The amplitude of such a voltage signal is proportional to the impacting force or impulse. The proportional factor can be calibrated. The forces can thus be read out from the recorded value of the voltage, The equation of motion for the pendulum system has been solved analytically. The circuit equation for the electronic measurement system has been formulated and solved numerically. Using this balance the thrust at the exhaust of a Tandem Mirror plasma thuster has been measured. The analytical solution of the overall characteristics agrees greatly with the measurement. (C) 1995 American Institute of Physics. C1 SW INST PHYS,SICHUAN,PEOPLES R CHINA. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP YANG, TF (reprint author), MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139, USA. NR 6 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD SEP PY 1995 VL 66 IS 9 BP 4637 EP 4643 DI 10.1063/1.1146490 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA RV679 UT WOS:A1995RV67900035 ER PT J AU VOORHIES, CV AF VOORHIES, CV TI LUNAR PHASE INFLUENCE ON GLOBAL TEMPERATURES SO SCIENCE LA English DT Article RP VOORHIES, CV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,CODE 921,GREENBELT,MD 20771, USA. RI Voorhies, Coerte/D-4672-2012 NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 1 PY 1995 VL 269 IS 5228 BP 1285 EP 1285 DI 10.1126/science.269.5228.1285 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RR842 UT WOS:A1995RR84200042 PM 17732116 ER PT J AU ASIMOV, D AF ASIMOV, D TI THERES NO SPACE LIKE HOME SO SCIENCES-NEW YORK LA English DT Article C1 STANFORD UNIV,DEPT MATH,STANFORD,CA 94305. RP ASIMOV, D (reprint author), NASA,AMES RES CTR,MT VIEW,CA, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0036-861X J9 SCIENCES JI Sci.-New York PD SEP-OCT PY 1995 VL 35 IS 5 BP 20 EP 25 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RZ927 UT WOS:A1995RZ92700018 ER PT J AU FROSCH, RA AF FROSCH, RA TI THE INDUSTRIAL ECOLOGY OF THE 21ST-CENTURY SO SCIENTIFIC AMERICAN LA English DT Article C1 UN,ENVIRONM PROGRAM,NEW YORK,NY 10017. NASA,WASHINGTON,DC 20546. GM CORP,DETROIT,MI 48202. NR 4 TC 7 Z9 7 U1 0 U2 2 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD SEP PY 1995 VL 273 IS 3 BP 178 EP 181 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RP670 UT WOS:A1995RP67000051 ER PT J AU BAILEY, DH SWARZTRAUBER, PN AF BAILEY, DH SWARZTRAUBER, PN TI EFFICIENT DETECTION OF A CONTINUOUS-WAVE SIGNAL WITH A LINEAR FREQUENCY DRIFT SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE SIGNAL DETECTION; FREQUENCY DRIFT; FAST FOURIER TRANSFORM AB An efficient method is presented for the detection of a continuous-wave (CW) signal with a frequency drift that is linear in time. Signals of this type occur if the transmitter and receiver are rapidly accelerating with respect to one another, for example, as in interplanetary and space communications. We assume that both the frequency and the drift are unknown. We also assume that the signal is weak compared with the Gaussian noise. The signal is partitioned into subsequences whose discrete Fourier transforms provide a sequence of instantaneous spectra at equal time intervals. These spectra are then accumulated with a shift that is proportional to time. When the shift is equal to the frequency drift, the signal-to-noise ratio increases and detection occurs. In this paper, we show how to compute these accumulations for many shifts in an efficient manner using a variant of the fast Fourier transform (FFT). Computing time is proportional to LlogL, where L is the length of the time series. Computational results are presented. C1 NATL CTR ATMOSPHER RES,BOULDER,CO 80307. RP BAILEY, DH (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD SEP PY 1995 VL 16 IS 5 BP 1233 EP 1239 DI 10.1137/0916071 PG 7 WC Mathematics, Applied SC Mathematics GA RR541 UT WOS:A1995RR54100013 ER PT J AU ANTHONY, WH HUTCHINSON, GL LIVINGSTON, GP AF ANTHONY, WH HUTCHINSON, GL LIVINGSTON, GP TI CHAMBER MEASUREMENT OF SOIL-ATMOSPHERE GAS-EXCHANGE - LINEAR VS DIFFUSION-BASED FLUX MODELS SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Note ID NITROUS-OXIDE AB We compared linear regression with a diffusion-based model for N2O flux estimation using non-steady-state chamber gas concentrations from a long-term study of N cycling in a managed grass pasture on sandy soil in southern Texas, Of 2224 chamber deployments, 449 met criteria established for using the diffusion-based model, which yielded flux estimates that averaged 54% larger than linear regression (n = 3). Although they represented only about 20% of all chamber deployments, this group included most of the data with greatest influence on the magnitude and dynamics of total N2O exchange at our site; e.g., of the 263 fluxes >10 g N ha(-1) d(-1), 199 (or 73%) were included, Apparently, application of a linear model to nonlinear chamber concentration data represents a potentially serious source of measurement bias that may influence not only summary statistics for the experiment, but also larger scale budgets based partially or wholly on those data. C1 USDA ARS,SOIL PLANT NUTRIENT RES UNIT,FT COLLINS,CO 80522. PRAIRIE VIEW AM UNIV,COOPERAT AGR RES CTR,PRAIRIE VIEW,TX 77446. NASA,AMES RES CTR,DIV EARTH SYST SCI,MOFFETT FIELD,CA 94035. NR 8 TC 50 Z9 51 U1 5 U2 40 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD SEP-OCT PY 1995 VL 59 IS 5 BP 1308 EP 1310 PG 3 WC Soil Science SC Agriculture GA RU917 UT WOS:A1995RU91700015 ER PT J AU LAU, YT RAMATY, R AF LAU, YT RAMATY, R TI EVOLUTION OF ENERGETIC PROTONS IN TWISTED MAGNETIC LOOPS SO SOLAR PHYSICS LA English DT Article ID SOLAR AB We study the evolution of an ensemble of energetic (1 GeV) protons in a twisted force-free magnetic loop. The protons are followed with a bounce-average method and they are subjected to collisions with ambient gas and pitch-angle scattering by plasma turbulence in the loop. The proton loss is initially by drift and later by scattering into the loss cone. Gamma rays are produced by pion decays resulting from nuclear reactions of these lost protons. It is found that in order to have long-lasting protons, one of the following scenarios should hold: (1) For small loops (of length similar to 2 X 10(9) cm), the twist angle should be about 2 pi and the turbulence level below 10(-8) erg cm(-3). (2) For large loops (greater than or similar to 10(10) cm), the turbulence level should be below 10(-6) erg cm(-3). These set the conditions for testing the trapping picture as a viable explanation for the observed eight-hour gamma-ray emission. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP LAU, YT (reprint author), UNIV MARYLAND,INST PLASMA RES,COLLEGE PK,MD 20742, USA. NR 12 TC 3 Z9 4 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 SEP PY 1995 VL 160 IS 2 BP 343 EP 352 DI 10.1007/BF00732812 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500008 ER PT J AU MIHALOV, JD STRANGEWAY, RJ AF MIHALOV, JD STRANGEWAY, RJ TI LARGE SOLAR-WIND DISTURBANCES DURING LATE MAY AND EARLY JUNE 1991 SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; COSMIC-RAY MODULATION; SOFT-X-RAY; FLARES; HELIOSPHERE; DECREASES AB Solar wind data from the Ames experiment aboard the Pioneer Venus Orbiter, coincident with a period of unprecedented solar activity that began at the end of May, 1991, within the highly active earlier portion of 1991, are summarized and discussed. Some comparison is made with corresponding data from Earth. Some particularly large, strong shocks and solar ejecta were observed at Venus. The solar longitude of Venus, relative to associated flares, varied over a wide range, for a series of flares that produced X-rays that saturated the GOES X-ray counters. Some of the disturbances at Venus must be due to CMEs with longitudinal extents up to similar to 40-50 deg. C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP MIHALOV, JD (reprint author), NASA,AMES RES CTR,PLANETARY SYST BRANCH,MOFFETT FIELD,CA 94035, USA. NR 35 TC 1 Z9 1 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 SEP PY 1995 VL 160 IS 2 BP 363 EP 370 DI 10.1007/BF00732814 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500010 ER PT J AU HOYT, DV SCHATTEN, KH AF HOYT, DV SCHATTEN, KH TI OVERLOOKED SUNSPOT OBSERVATIONS BY HEVELIUS IN THE EARLY MAUNDER MINIMUM, 1653-1684 SO SOLAR PHYSICS LA English DT Article AB In the book Machina Coelestis (1679), Johannes Hevelius lists his daily solar observations from 1653 to 1679. He mentions 19 sunspot groups during this interval, of which 14 are unique to Hevelius and five are confirmed by other observers. There are an additional 9 sunspot groups during this interval that were not observed by Hevelius. In five cases he was not observing, but in the other four cases he did observe but failed to comment upon sunspots. The spots he missed or failed to observe tend to occur near the end of his career. This suggests Hevelius occasionally missed sunspots but usually was a reliable observer. These observations are important because they provide us the only known daily listing of solar observations during the early years of the Maunder Minimum. They are also important because they were overlooked by Wolf, Spoerer, Maunder, Eddy, and others in their study of solar activity in the seventeenth century. They provide us the best record of the sunspot maximum of 1660 when one sunspot lasted at least 86 days as it traversed the solar disk four times. The same region was active for seven solar rotations. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOYT, DV (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20770, USA. NR 15 TC 22 Z9 22 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 SEP PY 1995 VL 160 IS 2 BP 371 EP 378 DI 10.1007/BF00732815 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500011 ER PT J AU HOYT, DV SCHATTEN, KH AF HOYT, DV SCHATTEN, KH TI OBSERVATIONS OF SUNSPOTS BY FLAMSTEED DURING THE MAUNDER MINIMUM SO SOLAR PHYSICS LA English DT Article AB In the book Historia Coelestis Brittannica, John Flamsteed (1725) lists his daily solar observations from 1676 onwards. Coupled with his comments in the Philosophical Transactions of the Royal Society and his letters to William Derham in the Cambridge University Library, it is possible to reconstruct a daily chronology of his solar and sunspot observations from 1676 to 1700. These observations are important because, coupled with daily logs of observations by Picard, La Hire, Eimmart, and others, a detailed record of the observations during a portion of the Maunder Minimum can be constructed. For example, for 1691, a typical year, the longest gap between observations is only four days. Flamsteed's observations are also important because they add to the data gathered by Wolf, Spoerer, Maunder, Eddy, and others in their study of solar activity in the seventeenth century. Flamsteed's observations are summarized here and a sample of his observations is presented. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOYT, DV (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20770, USA. NR 5 TC 19 Z9 19 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 SEP PY 1995 VL 160 IS 2 BP 379 EP 385 DI 10.1007/BF00732816 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500012 ER PT J AU HOYT, DV SCHATTEN, KH AF HOYT, DV SCHATTEN, KH TI A NEW INTERPRETATION OF HORREBOW,CHRISTIAN SUNSPOT OBSERVATIONS FROM 1761 TO 1777 SO SOLAR PHYSICS LA English DT Article AB Christian Horrebow and his colleagues of Copenhagen, Denmark, actively observed sunspots from 1761 to 1777. These observations were examined by Thiele in 1859 and by d'Arrest in 1873 with markedly different conclusions. Thiele reported nearly twice as many sunspot groups as d'Arrest. To resolve this discrepancy, we have reexamined Horrebow's original notebooks. We find slightly more sunspot groups then did d'Arrest. Thiele apparently called individual sunspots sunspot groups, so he would call a bipolar group two groups. d'Arrest seems to have missed counting some of the smaller sunspot groups. A correct interpretation of Horrebow's observations is required in efforts to reconstruct solar activity. Wolf gave a sunspot number for 1769 of 106.1. On the basis of our re-examination of Horrebow's drawings and other observers, we deduce a sunspot number of about 80.5 for 1769. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOYT, DV (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20770, USA. NR 3 TC 16 Z9 16 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 SEP PY 1995 VL 160 IS 2 BP 387 EP 392 DI 10.1007/BF00732817 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500013 ER PT J AU HOYT, DV SCHATTEN, KH AF HOYT, DV SCHATTEN, KH TI A REVISED LISTING OF THE NUMBER OF SUNSPOT GROUPS MADE BY PASTORFF, 1819 TO 1833 SO SOLAR PHYSICS LA English DT Article AB J. W. Pastorff of Drossen, Germany, made about 1477 observations of sunspots between 1819 and 1833. These observations were erroneously interpreted by A. C. Ranyard in 1874 and then used by Rudolf Wolf in his calculations of the Wolf Sunspot Numbers. The result is a noisier daily time series and overestimation of the monthly and yearly means for these years. Pastorff was actually a very good observer. In this paper, Pastorff's original observations are reexamined and more nearly correct values for the number of sunspot groups are tabulated. We show some examples of the problems created by Ranyard's interpretation and the consequences for the history of solar activity that a correct interpretation of Pastorff's observations will have. Pastorff's observations provide valuable information on the first strong cycle after the Dalton Minimum (1795-1823). C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOYT, DV (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20770, USA. NR 1 TC 15 Z9 15 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 SEP PY 1995 VL 160 IS 2 BP 393 EP 399 DI 10.1007/BF00732818 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RW855 UT WOS:A1995RW85500014 ER PT J AU SIMON, HD STROHMAIER, E AF SIMON, HD STROHMAIER, E TI AMDAHLS LAW AND THE STATISTICAL CONTENT OF THE NAS PARALLEL BENCHMARKS SO SUPERCOMPUTER LA English DT Article AB The NAS Parallel Benchmarks have been developed at the NASA Ames Research Center. In the last three years extensive performance data have been reported for parallel machines both based on the NAS Parallel Benchmarks [1, 2] and on LINPACK [3]. In this study we have used the reported benchmark results and performed a number of statistical experiments. These included cluster, factor and regression analyses. We did this to find out how many of the NAS Parallel Benchmarks are - in a statistical sense - necessary, to represent all the reported results. We also fitted Amdahl's Law to the data, to see whether it is meaningful to apply more sophisticated performance models to the reported results. All statistical experiments were done for absolute performances as well as for the corresponding efficiencies. The analysis of Amdahl's Law was performed for both classes (Class A and B) of the NAS Parallel Benchmarks. C1 UNIV MANNHEIM,CTR COMP,D-68131 MANNHEIM,GERMANY. COMP SCI CORP,SILVER SPRING,MD 20910. RP SIMON, HD (reprint author), NASA,AMES RES CTR,DIV NUMER AERODYNAM SIMULAT SYST,APPL RES BRANCH,MAIL STOP T27A-1,MOFFETT FIELD,CA 94035, USA. NR 3 TC 4 Z9 4 U1 0 U2 0 PU ASFRA PI EDAM PA VOORHAVEN 33, 1135 BL EDAM, NETHERLANDS SN 0168-7875 J9 SUPERCOMPUTER JI Supercomputer PD SEP PY 1995 VL 11 IS 4 BP 75 EP 88 PG 14 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA RV984 UT WOS:A1995RV98400006 ER PT J AU BAUSCHLICHER, CW AF BAUSCHLICHER, CW TI LARGE ATOMIC NATURAL ORBITAL BASIS-SETS FOR THE FIRST TRANSITION ROW ATOMS SO THEORETICA CHIMICA ACTA LA English DT Article DE ANO; BASIS SETS ID GAUSSIAN-BASIS SETS; 2ND-ORDER PERTURBATION-THEORY; CORRELATED MOLECULAR CALCULATIONS; ELECTRIC-DIPOLE MOMENT; COUPLED-CLUSTER THEORY; ANO BASIS-SETS; WAVE-FUNCTIONS; METAL ATOMS; 1ST-ROW; NIH AB Large atomic natural orbital (ANO) basis sets are tabulated for the Sc to Cu atoms. The primitive sets are taken from the large sets optimized by Partridge, namely (21s13p8d) for Sc and Ti and (20s12p9d) for V to Cu. These primitive sets are supplemented with three p, one d, six f, and four g functions. The ANO sets are derived from configuration interaction density matrices constructed as the average of the lowest states derived from the 3d(n)4s(2) and 3d(n+1)4s(1) occupations. For Ni, the S-1(3d(10)) State is included in the averaging. The choice of basis sets for molecular calculations is discussed. RP BAUSCHLICHER, CW (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 38 TC 114 Z9 114 U1 2 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD SEP PY 1995 VL 92 IS 3 BP 183 EP 198 PG 16 WC Chemistry, Physical SC Chemistry GA RY717 UT WOS:A1995RY71700003 ER PT J AU ZHOU, Y PRASKOVSKY, A ONCLEY, S AF ZHOU, Y PRASKOVSKY, A ONCLEY, S TI ON THE LIGHTHILL RELATIONSHIP AND SOUND GENERATION FROM ISOTROPIC TURBULENCE SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article AB In 1952 Lighthill (1952) developed a theory for determining the sound generated by a turbulent motion of a fluid. With some statistical assumptions, Proudman (1952) applied this theory to estimate the acoustic power of isotropic turbulence. Recently, Lighthill established a simple relationship that relates the fourth-order retarded-time and space covariance of his stress tenser to the corresponding second-order covariance and the turbulent flatness factor, without making statistical assumptions for a homogeneous turbulence. Lilley (1994) revisited Proudman's work and applied the Lighthill relationship to evaluate the radiated acoustic power directly from isotropic turbulence. After choosing the time separation dependence in the two-point velocity time and space covariance based on the insights gained from direct numerical simulations, Lilley concluded that the Proudman constant is determined by the turbulent flatness factor and the second-order spatial velocity covariance. In order to estimate the Proudman constant at high Reynolds numbers, we analyzed a unique data set of measurements in a large wind tunnel and atmospheric surface layer that covers a range of the Taylor microscale-based Reynolds number 2.0 x 10(3) less than or equal to R(lambda) less than or equal to 12.7 x 10(3). Our measurements demonstrate that the Lighthill relationship is a good approximation, providing additional support to Lilley's approach. The flatness factor is found between 2.7 and 3.3 and the second-order spatial velocity covariance is obtained. Based on these experimental data, the Proudman constant is estimated to be 0.68-3.68. C1 NATL CTR ATMOSPHER RES,DIV ATMOSPHER TECHNOL,BOULDER,CO 80707. RP ZHOU, Y (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681, USA. NR 14 TC 8 Z9 10 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD SEP PY 1995 VL 7 IS 5 BP 355 EP 361 DI 10.1007/BF00312414 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RZ155 UT WOS:A1995RZ15500003 ER PT J AU THEDINGA, JF JOHNSON, SW AF THEDINGA, JF JOHNSON, SW TI RETENTION OF JET-INJECTED MARKS ON JUVENILE COHO AND SOCKEYE-SALMON SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Note AB Juvenile coho salmon Oncorhynchus kisutch and sockeye salmon O. nerka were marked by jet injection to determine mark retention of three substances: Alcian Blue dye, black india ink, and acrylic paint (red, fluorescent yellow, and fluorescent orange). Fish were marked on the caudal fin and then held for 40 weeks in flow-through freshwater tanks. Coho and sockeye salmon both retained Alcian Blue and fluorescent orange marks best. The highest mark retention after 40 weeks was 73% for Alcian Blue marks on sockeye salmon. Overall mark retention was greater for orange-, yellow-, and black-marked coho salmon than for similarly marked sockeye salmon. Differences in growth rate-sockeye salmon grew about 7 mm more than coho salmon-probably contributed to the differences in mark retention between species. All colors appear suitable for short-term (<6 weeks) marks. For long-term (>6 weeks) marks, we recommend Alcian Blue dye or fluorescent orange or yellow acrylic paint for coho salmon and Alcian Blue dye for sockeye salmon. RP THEDINGA, JF (reprint author), NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 12 TC 11 Z9 11 U1 1 U2 5 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD SEP PY 1995 VL 124 IS 5 BP 782 EP 785 DI 10.1577/1548-8659(1995)124<0782:ROJIMO>2.3.CO;2 PG 4 WC Fisheries SC Fisheries GA RW500 UT WOS:A1995RW50000014 ER PT J AU LEU, MT TIMONEN, RS KEYSER, LF YUNG, YL AF LEU, MT TIMONEN, RS KEYSER, LF YUNG, YL TI HETEROGENEOUS REACTIONS OF HNO3(G)+NACL(S)-]HCL(G)+NANO3(S) AND N2O5(G)+NACL(S)-]CLNO2(G)+NANO3(S) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID NITRIC-ACID; HYDROGEN-CHLORIDE; RATE CONSTANTS; GASEOUS N2O5; ATOMIC CL; ICE FILMS; NACL; WATER; TROPOSPHERE; STRATOSPHERE AB The heterogeneous reactions of HNO3(g) + NaCl(s) --> HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) --> CINO2(g) + NaNO3(s) (eq 2) were investigated over the temperature range 223-296 K in a now-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(-8) similar to 2 x 10(-6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1 sigma) at 296 K and >0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(-4) at both 223 and 296 K. The gas-phase reaction product was identified as CINO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) --> 2HNO(3)(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HC1 and HNO3 in the marine troposphere are discussed. C1 CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP LEU, MT (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 43 TC 87 Z9 89 U1 2 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD AUG 31 PY 1995 VL 99 IS 35 BP 13203 EP 13212 DI 10.1021/j100035a026 PG 10 WC Chemistry, Physical SC Chemistry GA RR846 UT WOS:A1995RR84600026 ER PT J AU TONG, CYE BLUNDELL, R BUMBLE, B STERN, JA LEDUC, HG AF TONG, CYE BLUNDELL, R BUMBLE, B STERN, JA LEDUC, HG TI QUANTUM LIMITED HETERODYNE-DETECTION IN SUPERCONDUCTING NONLINEAR TRANSMISSION-LINES AT SUBMILLIMETER WAVELENGTHS SO APPLIED PHYSICS LETTERS LA English DT Article ID RECEIVERS AB A non-linear superconducting transmission line has been successfully employed in heterodyne detection of sub-millimeter waves. In our experiments an Nb/Al/AlOx/Nb tunnel junction, measuring 0.15 x 40 mu m, with a critical current density of about 2500 A/cm(2) is used as a distributed mixer element. We have demonstrated that quantum limited sensitivity can be achieved with this type of device. At 460 GHz, a Y-factor of 2.5 has been recorded, corresponding to a double-side-band receiver noise temperature of 80 K, The double-side-band conversion loss is about 1 dB and the mixer noise temperature is estimated to be 18(+/- 10) K. (C) 1995 American Institute of Physics. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP TONG, CYE (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 14 TC 28 Z9 28 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 28 PY 1995 VL 67 IS 9 BP 1304 EP 1306 DI 10.1063/1.114405 PG 3 WC Physics, Applied SC Physics GA RR042 UT WOS:A1995RR04200043 ER PT J AU ZAHNLE, K LOW, MMM AF ZAHNLE, K LOW, MMM TI A SIMPLE-MODEL FOR THE LIGHT-CURVE GENERATED BY A SHOEMAKER-LEVY-9 IMPACT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB The impact of a typical Shoemaker-Levy 9 fragment produced three Light peaks as seen from Earth. The first peak is related to the entry of the fragment into the Jovian atmosphere. The second peak occurs when the exploding fireball rises above Jupiter's limb into direct view from Earth. The third peak, much the brightest, occurs when the ejecta plume falls back on the atmosphere. By contrast, Galileo, which had a direct view of the impacts, saw two peaks, one at entry, and one at plumefall. Here we present a simple, highly idealized model of a ballistic plume, which we then use to fit the observed light curve of the R impact as recorded at Mauna Kea and Mount Palomar. From the light curve we find that the nominal R fragment had diameter 450-500 m and mass similar to 2 - 3 x 10(13) g. The uncertainty in the mass is probably about a factor of 3, with a smaller event more Likely than a larger one. C1 UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP ZAHNLE, K (reprint author), NASA,AMES RES CTR,MS 245-3,MOFFETT FIELD,CA 94035, USA. OI Mac Low, Mordecai-Mark/0000-0003-0064-4060 NR 26 TC 33 Z9 33 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD AUG 25 PY 1995 VL 100 IS E8 BP 16885 EP 16894 DI 10.1029/95JE01620 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RT914 UT WOS:A1995RT91400002 ER PT J AU GRIFFITH, CA ZAHNLE, K AF GRIFFITH, CA ZAHNLE, K TI INFLUX OF COMETARY VOLATILES TO PLANETARY MOONS - THE ATMOSPHERES OF 1000 POSSIBLE TITANS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID VOYAGER-1 RADIO-OCCULTATION; SOLAR-SYSTEM; GEOLOGICAL HISTORIES; CARBON-MONOXIDE; SATURN; SATELLITES; ABUNDANCE; DEUTERIUM; SURFACE; TEMPERATURE AB We use a Monte Carlo model to simulate impact histories of possible Titans, Callistos, and Ganymedes. Comets create or erode satellite atmospheres, depending on their mass and velocity distributions: faster and bigger comets remove atmophiles; slower or smaller comets supply them. Mass distributions and the minimum total mass of comets passing through the Saturn system were derived from the crater records of Rhea and Iapetus. These were then scaled to give a minimum impact history for Titan. From this cometary population, of 1000 initially airless Titans 16% acquired atmospheres larger than Titan's present atmosphere (9 x 10(21) g), and more than half accumulated atmospheres larger than 10(21) g. In contrast to the work of Zahnle et al. (1992), we find that, in most trials, Callisto acquires comet-based atmospheres. Atmospheres acquired by Callisto and, especially, Ganymede are sensitive to assumptions regarding energy partitioning into the ejecta plume. If we assume that only the normal velocity component heats the plume, the majority of Ganymedes and half of the Callistos accreted atmospheres smaller than 10(20) g. If all the impactor's velocity heats the plume, Callisto's most likely atmosphere is 10(17) g and Ganymede's is negligible. The true cometary flux was most likely larger than that derived from crater records, which raises the probability that Titan, Ganymede, and Callisto acquired substantial atmospheres. However, other loss processes (e.g., sputtering by ions swept up by the planetary magnetic field, solar UV photolysis of hydrocarbons) are potentially capable of eliminating small atmospheres over the age of the solar system. The dark material on Callisto's surface may be a remnant of an earlier, now vanished atmosphere. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP GRIFFITH, CA (reprint author), NO ARIZONA UNIV,DEPT PHYS & ASTRON,FLAGSTAFF,AZ 86011, USA. NR 68 TC 40 Z9 40 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD AUG 25 PY 1995 VL 100 IS E8 BP 16907 EP 16922 DI 10.1029/95JE01135 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RT914 UT WOS:A1995RT91400004 PM 11539417 ER PT J AU WEISSMAN, PR AF WEISSMAN, PR TI SOURCE OF COMETS SO SCIENCE LA English DT Letter RP WEISSMAN, PR (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD AUG 25 PY 1995 VL 269 IS 5227 BP 1120 EP 1120 DI 10.1126/science.269.5227.1120-a PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RQ748 UT WOS:A1995RQ74800056 ER PT J AU WALCH, SP AF WALCH, SP TI MINIMUM ENERGY PATHWAYS FOR CHEMICAL-REACTIONS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 2 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25900925 ER PT J AU TOLBERT, MA ANTHONY, SE DISSELKAMP, R AF TOLBERT, MA ANTHONY, SE DISSELKAMP, R TI COMPOSITION OF POLAR STRATOSPHERIC CLOUDS FROM INFRARED-SPECTROSCOPY SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV COLORADO,BOULDER,CO 80309. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 24 EP ENVR PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP256 UT WOS:A1995RP25601454 ER PT J AU LEE, TJ AF LEE, TJ TI AB-INITIO STUDIES OF HALOGEN AND NITROGEN-OXIDE SPECIES OF INTEREST IN STRATOSPHERIC CHEMISTRY SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 52 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25900971 ER PT J AU OKUMURA, M MOORE, TA CRELLIN, KC HAAS, BM KUWATA, KT NELSON, CM TAGAWA, M MINTON, TK AF OKUMURA, M MOORE, TA CRELLIN, KC HAAS, BM KUWATA, KT NELSON, CM TAGAWA, M MINTON, TK TI GAS-PHASE CHEMISTRY OF CHLORINE NITRATE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CALTECH,DEPT CHEM,PASADENA,CA 91125. JET PROP LAB,PASADENA,CA 91109. OSAKA UNIV,FAC MED,DEPT PRECIS ENGN,OSAKA,JAPAN. MONTANA STATE UNIV,CTR BIOFILM ENGN,BOZEMAN,MT 59717. MONTANA STATE UNIV,DEPT CHEM,BOZEMAN,MT 59717. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 53 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25900972 ER PT J AU NICKOLAISEN, SL MILLER, CE SANDER, SP HAND, MR WILLIAMS, IH AF NICKOLAISEN, SL MILLER, CE SANDER, SP HAND, MR WILLIAMS, IH TI PRESSURE-DEPENDENCE AND METASTABLE STATE FORMATION IN THE PHOTOLYSIS OF DICHLORINE MONOXIDE (CL2O) SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV BATH,SCH CHEM,BATH BA2 7AY,AVON,ENGLAND. JET PROP LAB,PASADENA,CA 91109. PURDUE UNIV,W LAFAYETTE,IN 47907. RI Williams, Ian/A-7598-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 54 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25900973 ER PT J AU COLLINS, A AF COLLINS, A TI WHAT THE NATIONAL SCIENCE-EDUCATION STANDARDS MIGHT SAY TO CHEMISTS AND CHEMISTRY EDUCATORS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NATL RES COUNCIL,TALLAHASSEE,FL 32306. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 77 EP CHED PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP256 UT WOS:A1995RP25600601 ER PT J AU STIEGMAN, AE SCOTT, GW TRAN, K THURSTON, T KIM, SS AF STIEGMAN, AE SCOTT, GW TRAN, K THURSTON, T KIM, SS TI ELECTRONIC-STRUCTURE AND PHOTOCHEMICAL OXIDATIONS AT DISCRETE SILICA-BOUND OXOVANADIUM SITES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 FLORIDA STATE UNIV,DEPT CHEM,TALLAHASSEE,FL 32316. UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521. JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 82 EP COLL PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP256 UT WOS:A1995RP25601127 ER PT J AU STIEGMAN, AE ANDERSON, MA KIM, SS AF STIEGMAN, AE ANDERSON, MA KIM, SS TI POLYMERIZATION OF ORGANIC MONOMERS IN AN ACTIVE SILICA XEROGEL MATRIX - A NEW ROUTE TO NANOCOMPOSITE FABRICATION SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 FLORIDA STATE UNIV,DEPT CHEM,TALLAHASSEE,FL 32316. JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 90 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25901562 ER PT J AU WELCH, PJ AF WELCH, PJ TI NON-CHLOROFLUOROCARBON CLEANING OF AEROSPACE HARDWARE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,DIV MAT SCI,KENNEDY SPACE CTR,FL 32899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 143 EP IEC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP256 UT WOS:A1995RP25602102 ER PT J AU SOUTHWARD, RE THOMPSON, DS THOMPSON, DW CAPLAN, ML STCLAIR, AK AF SOUTHWARD, RE THOMPSON, DS THOMPSON, DW CAPLAN, ML STCLAIR, AK TI REFLECTIVE POLYIMIDE FILMS VIA IN-SITU FORMATION OF A SILVERED SURFACE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 COLL WILLIAM & MARY,DEPT CHEM & APPL SCI,WILLIAMSBURG,VA 23187. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 206 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25901678 ER PT J AU GUADAGNINI, R SCHATZ, GC WALCH, SP AF GUADAGNINI, R SCHATZ, GC WALCH, SP TI THEORETICAL-STUDY OF SMALL HYDROCARBON REACTIONS IN SOOT FORMATION SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. NASA,AMES RES CTR,INST THERMOSCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 245 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP259 UT WOS:A1995RP25901160 ER PT J AU FINLEY, CW FERRANTE, J AF FINLEY, CW FERRANTE, J TI THE SPECTROSCOPIC PARAMETERS OF THE HETERODIATOMIC BIMETALLIC SPECIES OF NI, PD, PT, CU, AG AND AU ARE CALCULATED USING THE EMBEDDED-ATOM METHOD SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 PENN STATE UNIV,NEW KENSINGTON,PA 15068. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 20 PY 1995 VL 210 BP 349 EP CHED PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA RP256 UT WOS:A1995RP25600873 ER PT J AU MOTTELER, HE STROW, LL MCMILLIN, L GUALTIERI, JA AF MOTTELER, HE STROW, LL MCMILLIN, L GUALTIERI, JA TI COMPARISON OF NEURAL NETWORKS AND REGRESSION-BASED METHODS FOR TEMPERATURE RETRIEVALS SO APPLIED OPTICS LA English DT Article DE TEMPERATURE SOUNDING; REMOTE SENSING; NEURAL NETWORKS ID TIROS-N; INVERSION; HIRS2; MSU AB Two methods for performing clear-air temperature retrievals from simulated radiances for the Atmospheric Infrared Sounder are investigated. Neural networks are compared with a well-known Linear method in which regression is performed after a change of bases. With large channel sets, both methods can rapidly perform clear-air retrievals over a variety of climactic conditions with an overall RMS error of less than 1 K. The Jacobian of the neural network is compared with the Jacobian (the regression coefficients) of the linear method, revealing a more fine-scale variation than expected from the underlying physics, particularly for the neural net. Some pragmatic information concerning the application of neural nets to retrieval problems is also included. C1 UNIV MARYLAND,DEPT PHYS,BALTIMORE,MD 21228. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,CAMP SPRINGS,MD 20746. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. RP MOTTELER, HE (reprint author), UNIV MARYLAND,DEPT COMP SCI,BALTIMORE,MD 21228, USA. NR 11 TC 17 Z9 19 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 20 PY 1995 VL 34 IS 24 BP 5390 EP 5397 PG 8 WC Optics SC Optics GA RP421 UT WOS:A1995RP42100018 PM 21060360 ER PT J AU LU, NY FREUDLING, W AF LU, NY FREUDLING, W TI LARGE-SCALE STRUCTURES IN THE ZONE OF AVOIDANCE - THE GALACTIC ANTICENTER REGION SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, CLUSTERING; GALAXIES, DISTANCES AND REDSHIFTS; RADIO LINES, GALAXIES ID IRAS GALAXIES; MILKY-WAY; PERSEUS SUPERCLUSTER; SEARCH; 230-DEGREES; CLUSTER; 60-MU-M; SAMPLE; FIELD AB We have selected a sample of 876 galaxy candidates from the IRAS Point Source Catalog in the region of 2(h) < alpha < 10(h) and 0 degrees < delta < 36 degrees, which crosses the Galactic anticenter part of the Zone of Avoidance (ZOA) and includes most of the highly obscured Orion-Taurus complex region. We have identified galaxies among the candidate sources by attempting to detect the 21 cm H I line of those sources which were not known to be galaxies at the beginning of the survey. In this manner, we constructed a galaxy sample which is largely free from Galactic reddening. Of the 272 observed candidates, 89 were detected in the H I line up to a heliocentric velocity of upsilon(h) approximate to 16,000 km s(-1). The resulting galaxy sample of 717 galaxies is fairly complete (within about 10%) and uniform (within about 4%) in the part of the survey area 10 degrees away from the Galactic plane and for velocities up to at least 9000 km s(-1). This provides, for the first time, a largely unbiased view on the large-scale structures in much of the survey area. Our main results are the following: (1) Several large voids are identified. In particular, a void between alpha approximate to 3(h) and 4(h), up to upsilon(h) similar to 6000 km s(-1), separates the Pisces-Perseus supercluster at alpha < 3(h) from structures at alpha > 4(h); and a ''nearby void'' occupies most of our survey area and reaches out to a redshift of nearly 3000 km s(-1). (2) We found no nearby galaxy concentration that could significantly contribute to the ''Local Velocity Anomaly'' (LVA), but a general excess of galaxies around upsilon(h) similar to 5000 km s(-1) in the survey area. (3) The contrast between the ''Great Wall'' at upsilon(h) similar to 8500 km s(-)1 and the void in front of it appears to gradually diffuse out after it enters the Zone of Avoidance from the northern Galactic hemisphere. (4) Our data combined with other galaxy surveys in or near the Galactic anticenter part of the ZOA suggest that the main ridge of the Pisces-Perseus supercluster does also not extend to Abell 569, a duster in the northern Galactic hemisphere, and that the simple gravitational model consisting of the Local Void of Tully and Fisher, our nearby void, and Puppis and Fornax-Eridanus clusters would predict a LVA whose direction is probably too far away from that derived from observations. C1 EUROPEAN SO OBSERV, SPACE TELESCOPE EUROPEAN COORDINATING FACIL, D-85748 GARCHING, GERMANY. RP LU, NY (reprint author), CALTECH, JET PROP LAB, MS 100-22, PASADENA, CA 91125 USA. NR 54 TC 20 Z9 20 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 AUG 20 PY 1995 VL 449 IS 2 BP 527 EP 549 DI 10.1086/176077 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP424 UT WOS:A1995RP42400014 ER PT J AU LEE, SJ SCHRAMM, DN MATHEWS, GJ AF LEE, SJ SCHRAMM, DN MATHEWS, GJ TI A MERGER MODEL AND GLOBULAR-CLUSTER FORMATION SO ASTROPHYSICAL JOURNAL LA English DT Article DE GLOBULAR CLUSTERS, GENERAL; STARS, FORMATION ID AGE-METALLICITY RELATION; HELIUM DIFFUSION; STAR FORMATION; GALAXIES; HALO; DISK AB We propose a self-consistent model for globular cluster formation in, but not limited to, our Galaxy, based on the merger model of Mathews & Schramm (1993). Stars and star clusters form in bursts at the merging interfaces as protogalactic clouds collide. We describe the formation of those star clusters with a simple schematic Ansatz which takes into account the thermal and Kelvin-Helmholtz instabilities. It is shown that this model is consistent with many observational properties such as the age and metallicity distributions of globular clusters, the overall number of globular clusters, and the near constancy of the numbers of globular clusters in different size host galaxies. Most of the features of this merger model are insensitive to choices of parameters. However, the model does not produce as many high-metallicity clusters as observed. Possible explanations for this are presented. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556. RP LEE, SJ (reprint author), UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637, USA. NR 31 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1995 VL 449 IS 2 BP 616 EP 622 DI 10.1086/176083 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP424 UT WOS:A1995RP42400020 ER PT J AU PALUMBO, ME TIELENS, AGGM TOKUNAGA, AT AF PALUMBO, ME TIELENS, AGGM TOKUNAGA, AT TI SOLID CARBONYL SULFIDE (OCS) IN W33A SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, ISM, LINES AND BANDS; ISM, CLOUDS; ISM, INDIVIDUAL (W33); ISM, MOLECULES; LINE, IDENTIFICATION; MOLECULAR PROCESSES ID ABSORPTION FEATURES; INFRARED-SPECTROSCOPY; MICRON ABSORPTION; METHANOL; ICE; CO; REGION; BAND AB We present ground-based observations of the 2041 cm(-1) (4.9 mu m) absorption We attribute this interstellar feature to solid carbonyl sulphide (OCS) embedded in icy grain mantles along the line of sight. We have made an extensive laboratory study of the infrared characteristics of OCS in various ice mixtures. Studies of the 2041 cm(-1) band of solid OCS and solid mixtures containing OCS show that its shape and peak position are sensitive to the molecular environment of the OCS molecule. Mie scattering calculations show that the peak position and profile of the OCS band depend on the shape and size of the absorbing grain when the OCS concentration is larger than 0.05. For lower OCS concentrations, laboratory-measured bulk spectra agree very well with the absorption spectra of small grains. We have compared the observed feature with laboratory and theoretical spectra of astrophysically relevant mixtures. The best agreement is obtained for mixtures with traces of OCS in a methanol-rich matrix. This would suggest the presence of independent grain components and in particular of a minor fraction of methanol-rich icy grain mantles in which OCS is embedded. From the strength of the absorption feature we deduce a OCS/H2O ratio, along the line of sight, of 4 x 10(-4). C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. RP PALUMBO, ME (reprint author), UNIV CATANIA, IST ASTRON, VIALE A DORIA 6, I-95125 CATANIA, ITALY. NR 29 TC 73 Z9 73 U1 0 U2 6 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 AUG 20 PY 1995 VL 449 IS 2 BP 674 EP 680 DI 10.1086/176088 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP424 UT WOS:A1995RP42400025 ER PT J AU STAPELFELDT, KR BURROWS, CJ KRIST, JE TRAUGER, JT HESTER, JJ HOLTZMAN, JA BALLESTER, GE CASERTANO, S CLARKE, JT CRISP, D EVANS, RW GALLAGHER, JS GRIFFITHS, RE HOESSEL, JG MOULD, JR SCOWEN, PA WATSON, AM WESTPHAL, JA AF STAPELFELDT, KR BURROWS, CJ KRIST, JE TRAUGER, JT HESTER, JJ HOLTZMAN, JA BALLESTER, GE CASERTANO, S CLARKE, JT CRISP, D EVANS, RW GALLAGHER, JS GRIFFITHS, RE HOESSEL, JG MOULD, JR SCOWEN, PA WATSON, AM WESTPHAL, JA TI WFPC2 IMAGING OF THE CIRCUMSTELLAR NEBULOSITY OF HL TAURI SO ASTROPHYSICAL JOURNAL LA English DT Article DE CIRCUMSTELLAR MATTER; STARS, INDIVIDUAL (HL TAURI); STARS, PRE-MAIN-SEQUENCE ID YOUNG STELLAR OBJECTS; HERBIG-HARO OBJECTS; STARS; DISKS; CLOUDS; PHOTOMETRY; EMISSION; OUTFLOWS; SPECTRA; EXCESS AB Planetary camera images of HL Tauri have been obtained through V-, R-, and I-band filters using the Wide Field and Planetary Camera 2 aboard the refurbished Hubble Space Telescope. These images show that HL Tauri is entirely reflection nebulosity at optical wavelengths, with no optical star visible to a limiting magnitude of V = 25.5. The optical nebula extends northeast of the stellar position along the direction of HL Tau's optical jet and has an unusual C-shaped morphology. The bright core of the nebula is only 1 '' in size and is centered only 1 ''.2 from the actual stellar position. We estimate that visual extinction toward the unseen point source is at least 22 mag and that the stellar photospheric luminosity must be at least 3 L.. These findings corroborate other evidence that this star is significantly younger and more embedded than typical T Tauri stars. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. LOWELL OBSERV,FLAGSTAFF,AZ 86001. UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,WESTON,ACT 2611,AUSTRALIA. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP STAPELFELDT, KR (reprint author), CALTECH,JET PROP LAB,MAIL STOP 179-225,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Stapelfeldt, Karl/D-2721-2012; Clarke, John/C-8644-2013 NR 39 TC 68 Z9 68 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1995 VL 449 IS 2 BP 888 EP 893 DI 10.1086/176106 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP424 UT WOS:A1995RP42400043 ER PT J AU ZHANG, W JAHODA, K SWANK, JH MORGAN, EH GILES, AB AF ZHANG, W JAHODA, K SWANK, JH MORGAN, EH GILES, AB TI DEAD-TIME MODIFICATIONS TO FAST FOURIER-TRANSFORM POWER SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article DE INSTRUMENTATION, DETECTORS; METHODS, DATA ANALYSIS AB Time series analysis in X-ray astronomy is complicated by the effects of detector dead time which can cause significant departures of power spectra from those expected from simple Poisson statistics. In this paper we study the effects of both the paralyzable and nonparalyzable dead times on the underlying time series which obeys Poisson counting statistics. We present analytical formulae for the autocorrelation function, autocovariances, and power spectra, for both kinds of dead time. These formulae, taken as a whole, offer a general qualitative and quantitative framework to further understand the effects of dead time in an X-ray detection and data processing system. C1 MIT, CTR SPACE RES, CAMBRIDGE, MA 02139 USA. RP ZHANG, W (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RI Jahoda, Keith/D-5616-2012; Swank, Jean/F-2693-2012 NR 16 TC 156 Z9 159 U1 0 U2 5 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 AUG 20 PY 1995 VL 449 IS 2 BP 930 EP 935 DI 10.1086/176111 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP424 UT WOS:A1995RP42400048 ER PT J AU GATES, EI GYUK, G TURNER, MS AF GATES, EI GYUK, G TURNER, MS TI THE LOCAL HALO DENSITY SO ASTROPHYSICAL JOURNAL LA English DT Article DE DARK MATTER; GALAXY, HALO; GALAXY, STRUCTURE; GRAVITATIONAL LENSING ID DARK-MATTER; GALACTIC HALO; MASS DENSITY; GALAXY; UNIVERSE; MODEL AB For almost 20 years models of the Galaxy have included a dark halo responsible for supporting a substantial fraction of the local rotation velocity and a flat rotation curve at large distances. Estimates of the local halo density range from 2 x 10(-25) g cm(-3) to 10 X 10(-25) g cm(-3). BY careful modeling of the Galaxy, taking account of the evidence that dark halos are flattened and recent microlensing data, we arrive at a more quantitative estimate, 9.2(-3.1)(+3.8) X 10(-25) g cm(-3). Microlensing toward the LMC indicates that only a small fraction, less than similar to 30%, can be in the form of MACHOs, which is consistent with the idea that most of the halo consists of cold dark matter particles. C1 FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60510 USA. UNIV CHICAGO, ENRICO FERMI INST, DEPT PHYS, CHICAGO, IL 60637 USA. RP GATES, EI (reprint author), UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, 5640 S ELLIS AVE, CHICAGO, IL 60637 USA. NR 50 TC 108 Z9 109 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 AUG 20 PY 1995 VL 449 IS 2 BP L123 EP L126 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP425 UT WOS:A1995RP42500007 ER PT J AU JOY, M PRESTWICH, AH BURTON, M GUIMOND, S AF JOY, M PRESTWICH, AH BURTON, M GUIMOND, S TI EXTENDED INFRARED-EMISSION IN THE GALAXY CLUSTER 1E-1111.9-3754 - NO EVIDENCE FOR A LOW-MASS ACCRETION POPULATION SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; INFRARED, GALAXIES ID COOLING FLOWS; PHOTOMETRIC SYSTEM AB Optical observations of an extended red halo surrounding the galaxy 1E 1111.9-3754 sparked considerable interest as potentially the first detection of low-mass star formation in an X-ray cooling flow. To test this possibility, we obtained near-infrared surface photometry of this galaxy at J (1.25 mu m) and K (2.15 mu m) and compare this data with models of a low-mass stellar accretion population. Our surface brightness measurements are consistent with a normal r(1/4) elliptical galaxy profile and show no evidence of an extended infrared halo, which argues against the low-mass stellar accretion hypothesis. C1 SMITHSONIAN ASTROPHYS OBSERV,CAMBRIDGE,MA 02138. UNIV NEW S WALES,SCH PHYS,KENSINGTON,NSW 2033,AUSTRALIA. MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717. RP JOY, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES84,HUNTSVILLE,AL 35812, USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1995 VL 449 IS 2 BP L113 EP L115 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP425 UT WOS:A1995RP42500004 ER PT J AU MACOMB, DJ AKERLOF, CW ALLER, HD ALLER, MF BERTSCH, DL BRUHWEILER, F BUCKLEY, JH CARTERLEWIS, DA CAWLEY, MF CHENG, KP DERMER, C FEGAN, DJ GAIDOS, JA GEAR, WK HALL, CR HARTMAN, RC HILLAS, AM KAFATOS, M KERRICK, AD KNIFFEN, DA KONDO, Y KUBO, H LAMB, RC MAKINO, F MAKISHIMA, K MARSCHER, A MCENERY, J MCHARDY, IM MEYER, DI MOORE, EM RAMOS, E ROBSON, EI ROSE, HJ SCHUBNELL, MS SEMBROSKI, G STEVENS, JA TAKAHASHI, T TASHIRO, M WEEKES, TC WILSON, C ZWEERINK, J AF MACOMB, DJ AKERLOF, CW ALLER, HD ALLER, MF BERTSCH, DL BRUHWEILER, F BUCKLEY, JH CARTERLEWIS, DA CAWLEY, MF CHENG, KP DERMER, C FEGAN, DJ GAIDOS, JA GEAR, WK HALL, CR HARTMAN, RC HILLAS, AM KAFATOS, M KERRICK, AD KNIFFEN, DA KONDO, Y KUBO, H LAMB, RC MAKINO, F MAKISHIMA, K MARSCHER, A MCENERY, J MCHARDY, IM MEYER, DI MOORE, EM RAMOS, E ROBSON, EI ROSE, HJ SCHUBNELL, MS SEMBROSKI, G STEVENS, JA TAKAHASHI, T TASHIRO, M WEEKES, TC WILSON, C ZWEERINK, J TI MULTIWAVELENGTH OBSERVATIONS OF MARKARIAN-421 DURING A TEV X-RAY FLARE SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL LACERTAE OBJECTS, GENERAL; BL LACERTAE OBJECTS, INDIVIDUAL (MARKARIAN 421) ID SIMULTANEOUS MULTIFREQUENCY OBSERVATIONS; LACERTAE OBJECT MARKARIAN-421; EMISSION AB A TeV flare from the BL Lac object Mrk 421 was detected in May of 1994 by the Whipple Observatory air Cherenkov experiment during which the flux above 250 GeV increased by nearly an order of magnitude over a 2-day period. Contemporaneous observations by ASCA showed the X-ray flux to be in a very high state. We present these results, combined with the first ever simultaneous or nearly simultaneous observations at GeV gamma-ray, UV, IR, mm, and radio energies for this nearest BL Lac object. While the GeV gamma-ray flux increased slightly, there is little evidence for variability comparable to that seen at TeV and X-ray energies. Other wavelengths show even less variability. This provides important constraints on the emission mechanisms at work. We present the multiwavelength spectrum of this gamma-ray blazar for both quiescent and flaring states and discuss the data in terms of current models of blazar emission. C1 UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109. UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. CATHOLIC UNIV AMER,WASHINGTON,DC 20064. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. ST PATRICKS COLL,DEPT PHYS,MAYNOOTH,KILDARE,IRELAND. USN,RES LAB,DIV SPACE SCI,WASHINGTON,DC 20375. PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. UNIV LEEDS,DEPT PHYS,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND. GEORGE MASON UNIV,CSI,INST SCI & TECHNOL,SPACE SCI PROGRAM,FAIRFAX,VA 22030. HAMPDEN SYDNEY COLL,DEPT PHYS & ASTRON,HAMPDEN SYDNEY,VA 23943. UNIV TOKYO,DEPT PHYS,BUNKYO KU,TOKYO 113,JAPAN. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. BOSTON UNIV,DEPT ASTRON,BOSTON,MA 02215. UNIV SOUTHAMPTON,DEPT PHYS,SOUTHAMPTON SO9 5NH,HANTS,ENGLAND. JOINT ASTRON CTR,HILO,HI 96720. UNIV CENT LANCASHIRE,CTR ASTROPHYS,PRESTON PR1 2HE,LANCS,ENGLAND. UNIV COLL DUBLIN,DEPT PHYS,DUBLIN 4,IRELAND. HARVARD SMITHSONIAN CTR ASTROPHYS,WHIPPLE OBSERV,AMADO,AZ 85645. RP MACOMB, DJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI McEnery, Julie/D-6612-2012; Tashiro, Makoto/J-4562-2012 NR 27 TC 119 Z9 121 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1995 VL 449 IS 2 BP L99 EP L103 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP425 UT WOS:A1995RP42500001 ER PT J AU SMITH, GL SMITH, NM AF SMITH, GL SMITH, NM TI SCENE IDENTIFICATION ERROR PROBABILITIES FOR EVALUATING EARTH RADIATION MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NIMBUS-7 ERB; BUDGET; CLOUD; ALGORITHMS AB The computation of radiant fluxes from radiance measurements by satellite radiometers requires the use of a bidirectional model. The bidirectional model, in turn, depends on the scene, so that a scene identification algorithm is required. The accuracy of scene identification varies with viewing zenith angle due mainly to geometric effects of the clouds and the measurements. This paper investigates the effects of viewing zenith angle on scene identification errors. Along-track measurements from the Earth Radiation Budget Experiment (ERBE) have been analyzed to quantify the probabilities of identifying a given scene as td its level of cloudiness, as used by the ERBE data processing system. Scene identification probabilities were initially computed on the basis of a select set of pixels. These restricted scene identification probabilities were then used to compute scene identification probabilities for all pixels, including those of marginal scene type. These probabilities are found to be functions of viewing zenith angle, but are insensitive to other parameters such as solar zenith angle, relative azimuth, and latitude, except in the Sun glint region. For most cases, the scene identification probabilities change very slowly for viewing zenith angle less than 40 degrees, but change rapidly for viewing zenith angle greater than 50 degrees. With increasing viewing zenith angles, the probability increases for identifying a scene as being more cloudy than its true cloud class. These results are useful for evaluation of flux errors due to scene identification errors in the data processing. C1 LOCKHEED ENGN & SCI CO, HAMPTON, VA 23666 USA. RP SMITH, GL (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. NR 18 TC 3 Z9 3 U1 0 U2 0 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 AUG 20 PY 1995 VL 100 IS D8 BP 16377 EP 16385 DI 10.1029/95JD01463 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700012 ER PT J AU CERNIGLIA, MC ROOD, RB DOUGLASS, AR AF CERNIGLIA, MC ROOD, RB DOUGLASS, AR TI 3-DIMENSIONAL SIMULATION OF THE INFLUENCE OF A CUTOFF LOW ON THE DISTRIBUTION OF NORTHERN-HEMISPHERE PROCESSED AIR IN LATE JANUARY 1992 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONSTITUENT TRANSPORT CALCULATIONS; ARCTIC TROPOPAUSE FOLD; OFF-LOW SYSTEMS; POTENTIAL VORTICITY; LOWER STRATOSPHERE; MIDDLE LATITUDES; OZONE; CONSERVATION; CHLORINE; EXCHANGE AB The NASA Goddard three-dimensional chemistry and transport model (3D CTM), utilizing winds and temperatures from a stratospheric data assimilation, is used to investigate the influence of a large cutoff low (COL) system on the transport of chemically processed stratospheric air. The conversion of hydrogen chloride to reactive chlorine is simulated for the early winter of 1991/1992. This heterogeneously converted air is defined as being processed. Throughout December and early January, simulated processed air remained nearly isolated within the Arctic vortex. In late January there were intrusions of midlatitude air across the boundary of the vortex over the North Atlantic and northwestern Europe. These intrusions, which are associated with horizontal transport associated with the COL system, dilute regions of highly processed air within several days. The simulation demonstrates the importance of synoptic scale events on processed air distribution within the vortex as well as transport out of the vortex base into the upper troposphere and midlatitudes. C1 APPL RES CORP, LANDOVER, MD 20785 USA. RP CERNIGLIA, MC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 916, GREENBELT, MD 20771 USA. RI Douglass, Anne/D-4655-2012; Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 NR 40 TC 8 Z9 8 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1995 VL 100 IS D8 BP 16431 EP 16443 DI 10.1029/95JD00689 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700016 ER PT J AU MORRIS, GA SCHOEBERL, MR SPARLING, LC NEWMAN, PA LAIT, LR ELSON, L WATERS, J SUTTIE, RA ROCHE, A KUMER, J RUSSELL, JM AF MORRIS, GA SCHOEBERL, MR SPARLING, LC NEWMAN, PA LAIT, LR ELSON, L WATERS, J SUTTIE, RA ROCHE, A KUMER, J RUSSELL, JM TI TRAJECTORY MAPPING AND APPLICATIONS TO DATA FROM THE UPPER-ATMOSPHERE RESEARCH SATELLITE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR VORTEX; STRATOSPHERE AB The problem of creating synoptic maps from asynoptically gathered trace gas data has prompted the development of a number of schemes. Most notable among these schemes are the Kalman filter, the Salby-Fourier technique, and constituent reconstruction. This paper explores a new technique called ''trajectory mapping.'' Trajectory mapping creates synoptic maps from asynoptically gathered data by advecting measurements backward or forward in time using analyzed wind fields. A significant portion of this work is devoted to an analysis of errors in synoptic trajectory maps associated with the calculation of individual parcel trajectories. In particular, we have considered (1) calculational errors; (2) uncertainties in the values and locations of constituent measurements, (3) errors incurred by neglecting diabatic effects, and (4) sensitivity to differences in wind field analyses, These studies reveal that the global fields derived from the advection of large numbers of measurements are relatively insensitive to the errors in the individual trajectories. The trajectory mapping technique has been successfully applied to a variety of problems. In this paper, the following two applications demonstrate the usefulness of the technique: an analysis of dynamical wave-breaking events and an examination of Upper Atmosphere Research Satellite data accuracy. C1 RICE UNIV, DEPT SPACE PHYS & ASTRON, HOUSTON, TX 77251 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. LOCKHEED PALO ALTO RES LABS, PALO ALTO, CA 94304 USA. HUGHES STX CORP, LANHAM, MD 20706 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. HERIOT WATT UNIV, EDINBURGH, MIDLOTHIAN, SCOTLAND. RP MORRIS, GA (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 916, GREENBELT, MD 20771 USA. RI Newman, Paul/D-6208-2012 OI Newman, Paul/0000-0003-1139-2508 NR 23 TC 48 Z9 48 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1995 VL 100 IS D8 BP 16491 EP 16505 DI 10.1029/95JD01072 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700018 ER PT J AU CLOUGH, SA RINSLAND, CP BROWN, PD AF CLOUGH, SA RINSLAND, CP BROWN, PD TI RETRIEVAL OF TROPOSPHERIC OZONE FROM SIMULATIONS OF NADIR SPECTRAL RADIANCES AS OBSERVED FROM SPACE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE; TEMPERATURE; POLLUTION AB The global remote sensing of tropospheric ozone profiles is a critical environmental measurement to be performed by future satellite experiments. We have applied the method of nonlinear least squares in conjunction with an efficient and accurate line-by-line radiative transfer model to directly retrieve vertical profiles of tropospheric ozone from simulated dear sky, nadir-viewing radiances covering the entire 9.6-mu m ozone band. The simulations have been generated for the specifications of the tropospheric emission spectrometer (TES), a Fourier transform spectrometer with 0.032 cm(-1) resolution (half width at half maximum (HWHM), unapodized) being developed for NASA's Earth Observing System. Profile retrieval errors for background tropospheric ozone levels are characterized as a function of measurement noise, spectral resolution, and vertical resolution based on a linear error analysis and an initial guess profile with minimal constraint, hence negligible potential profile bias at all altitudes. The main conclusions of the study are that (1) for the TES experiment design, ozone profiles are retrievable to approximately +/-5% (1 sigma) for a vertical resolution of 5 km in the middle and upper troposphere, (2) the stratospheric portion of the profile must be retrieved directly from the measured nadir spectrum, (3) for equal measurement times and considering the effects of both systematic error and source radiance noise, an optimal spectral interferometer resolution exists that is close to the TES resolution (0.032 cm(-1); HWHM unapodized), and (4) ozone boundary layer retrievals are highly dependent on the contrast between that layer and the surface. The results from an ozone retrieval utilizing simulated radiances from an atmosphere defined by a radiosonde observation at Ascension Island are considered in the context of the solution of the nonlinear problem and the linear error analysis, The ozone retrieval analyses presented in this paper are principally concerned with the effects of measurement error and thus represent the optimal retrieval capability for the assumed design. However, the availability of the full high-resolution spectrum will enable the detection and mitigation of the systematic errors. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. RP CLOUGH, SA (reprint author), ATMOSPHER & ENVIRONM RES INC, 840 MEM DR, CAMBRIDGE, MA 02139 USA. NR 32 TC 43 Z9 43 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1995 VL 100 IS D8 BP 16579 EP 16593 DI 10.1029/95JD01388 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700023 ER PT J AU POUGATCHEV, NS CONNOR, BJ RINSLAND, CP AF POUGATCHEV, NS CONNOR, BJ RINSLAND, CP TI INFRARED MEASUREMENTS OF THE OZONE VERTICAL-DISTRIBUTION ABOVE KITT PEAK SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FOURIER-TRANSFORM SPECTROSCOPY; LASER HETERODYNE SPECTROMETER; SOLAR SPECTRA; PROFILES; ABSORPTION; OXIDE AB The vertical distribution of the ozone in the troposphere and the lower and middle stratosphere has been retrieved from a series 0.005-0.013 cm(-1) resolution infrared solar spectra recorded with the McMath Fourier transform spectrometer at the National Solar Observatory on Kitt Peak. The analysis is based on a multilayer line-by-line forward model and a semiempirical version of the optimal estimation inversion method by Rodgers. The 1002.6-1003.2 cm(-1) spectral interval has been selected for the analysis on the basis of synthetic spectrum calculations. The characterization and error analysis of the method have been performed. It was shown that for the Kitt Peak spectral resolution and typical signal-to-noise ratio (greater than or equal to 100) the retrieval is stable, with the vertical resolution of approximate to 5 km attainable near the surface degrading to approximate to 10 km in the stratosphere. Spectra recorded from 1980 through 1993 have been analyzed. The retrieved total ozone and vertical profiles have been compared with total ozone mapping spectrometer (TOMS) satellite total columns for the location and dates of the Kitt Peak measurements and about 100 ozone ozonesoundings and Brewer total column measurements from Palestine, Texas, from 1979 to 1985. The total ozone measurements agree to +/- 2%. The retrieved profiles reproduce the seasonally averaged variations with altitude, including the ozone spring maximum and fall minimum measured by Palestine sondes, but up to 15% differences in the absolute values are obtained. C1 CHRISTOPHER NEWPORT UNIV, NEWPORT NEWS, VA USA. RP POUGATCHEV, NS (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. NR 32 TC 107 Z9 107 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1995 VL 100 IS D8 BP 16689 EP 16697 DI 10.1029/95JD01296 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700031 ER PT J AU HALL, TM PRATHER, MJ AF HALL, TM PRATHER, MJ TI SEASONAL EVOLUTIONS OF N2O, O-3, AND CO2 - 3-DIMENSIONAL SIMULATIONS OF STRATOSPHERIC CORRELATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC OZONE; TRACE CONSTITUENTS; NITROUS-OXIDE; ARCTIC VORTEX; POLAR VORTEX; TROPOSPHERE; EXPEDITION; ATMOSPHERE; CHEMISTRY; EXCHANGE AB Fluctuations in the concentrations of stratospheric trace gases are often correlated over a large range of space and time scales, an observation frequently used to infer the existence of various chemical processes. Three-dimensional models provide a tool to examine the causes and variations of trace gas relationships, because they can realistically simulate the interplay between stratospheric photochemistry and meteorology. Thus such models can aid the interpretation of observed trace gas relationships. We use the general circulation model of the Goddard Institute for Space Studies to simulate the evolution and distribution of N2O, CO2, and O-3 over a year. In the modeled lower stratosphere the constituents N2O and CO2 have well-correlated spatial variations, but the slope of the regression line depends on both the season and the direction of sampling. This departure from a universal form is due both to the annual cycle in tropospheric CO2 and to transport of air from the upper stratosphere photochemically depleted in N2O. Due to the short photochemical Lifetime of tropical O-3, its relationship with N2O is still more varied. In particular, the slope of the O-3-N2O regression line changes significantly from middle to high latitudes, behavior relevant to the use of N2O for estimating the rate of polar winter O-3 depletion. In general, a tight correlation between two trace gases such as N2O and O-3 is Often observed, but this datum cannot be used to infer a similar universal relationship because a different direction of sampling may change the slope and the scatter about it. C1 NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. COLUMBIA UNIV, NEW YORK, NY 10025 USA. UNIV CALIF IRVINE, DEPT EARTH SYST SCI, IRVINE, CA 92717 USA. NR 39 TC 40 Z9 40 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 20 PY 1995 VL 100 IS D8 BP 16699 EP 16720 DI 10.1029/94JD03300 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700032 ER PT J AU REMSBERG, E BURTON, J GORDLEY, L MARSHALL, BT BHATT, P MILES, T AF REMSBERG, E BURTON, J GORDLEY, L MARSHALL, BT BHATT, P MILES, T TI IMPROVEMENTS IN NIMBUS-7 LIMB INFRARED MONITOR OF THE STRATOSPHERE OZONE PROFILES AS OBTAINED WITH UPDATED SPECTRAL-LINE PARAMETERS AND RADIANCE ALGORITHMS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ABSOLUTE ABSORPTION; VALIDATION AB Ozone distributions from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) experiment of 1978-1979 are generally in good agreement with other concurrent ozone measurements in, the middle and upper stratosphere, but not at lower altitudes. LIMS ozone is too large below about the 15-hPa (or millibar) level, particularly at lower latitudes. A new LIMS ozone distribution is presented for 1 day of profiles, May 5, 1979, obtained with an improved forward radiance algorithm and using the spectral line parameters for the 9- to 10-mu m region in the HITRAN 92 compilation. However, we also divided our single day of retrieved ozone mixing ratio profiles by a suggested factor of 1.051, which makes them compatible with the ozone distributions from several of the UARS experiments. Our revised distribution still agrees with the archived LIMS ozone to better than +/- 5% above about the 15-hPa level, but there is a significant decrease for the revised ozone in the lower stratosphere. That decrease approaches 25% at 50 hPa in the tropics. In general, the revised LIMS ozone is now in accord with the comparison data sets for the stratosphere, except for the lowest levels (Umkehr layer 3 or 63-127 hPa), where the effects of interfering species and small biases in LIMS temperatures are most pronounced. It is concluded that the current 9- to 10-mu m ozone line list is adequate for obtaining good quality ozone mixing ratio profiles from satellite broadband limb-infrared measurements. C1 GATS INC, HAMPTON, VA USA. SCI APPLICAT INT CORP, HAMPTON, VA USA. HUGHES STX CORP, GREENBELT, MD USA. RP REMSBERG, E (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. NR 25 TC 4 Z9 4 U1 0 U2 0 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 AUG 20 PY 1995 VL 100 IS D8 BP 16727 EP 16733 DI 10.1029/95JD01745 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700034 ER PT J AU RANDEL, WJ WU, F RUSSELL, JM WATERS, JW FROIDEVAUX, L AF RANDEL, WJ WU, F RUSSELL, JM WATERS, JW FROIDEVAUX, L TI OZONE AND TEMPERATURE-CHANGES IN THE STRATOSPHERE FOLLOWING THE ERUPTION OF MOUNT-PINATUBO SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; EL-CHICHON; TROPICAL OZONE; MT PINATUBO; TOMS DATA; AEROSOLS; CIRCULATION; DEPLETION; TRENDS AB Global variations in stratospheric ozone and lower stratospheric temperature are documented for the period 1991-1994, following the eruption of Mount Pinatubo in June 1991. Column ozone measurements are from the total ozone mapping spectrometer instruments on the Nimbus 7 and Meteor 3 satellites, together with solar backscattered ultraviolet data from NOAA 11; these satellite ozone data are validated by comparisons with ground-based Dobson spectrophotometer measurements. Ozone profile data from the halogen occultation experiment and microwave limb sounder instruments on the upper atmosphere research satellite are also analyzed. Satellite temperature data are from the microwave sounding unit channel 4, representing a mean of the 150- to 50-mbar layer. The ozone observations show substantial decreases in column ozone (of order 5-10%) over large regions of the globe; largest losses are observed in northern hemisphere middle-high latitudes during winter-spring of each year (largest in 1992-1993), over southern hemisphere high latitudes in spring 1993, and episodically over the tropics during 1991-1993. Temperatures are anomalously warm (by order 1 K) over 30 degrees N-S for 1 to 2 years following the eruption. Significant cold anomalies are also observed over the northern hemisphere polar cap during summer 1993, a result probably related to the decreased ozone levels throughout 1993. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. CALTECH, JET PROP LAB, PASADENA, CA USA. RP RANDEL, WJ (reprint author), NATL CTR ATMOSPHER RES, POB 3000, BOULDER, CO 80307 USA. RI Randel, William/K-3267-2016 OI Randel, William/0000-0002-5999-7162 NR 48 TC 103 Z9 108 U1 2 U2 12 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 AUG 20 PY 1995 VL 100 IS D8 BP 16753 EP 16764 DI 10.1029/95JD01001 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700036 ER PT J AU SPARLING, LC SCHOEBERL, MR AF SPARLING, LC SCHOEBERL, MR TI MIXING ENTROPY ANALYSIS OF DISPERSAL OF AIRCRAFT EMISSIONS IN THE LOWER STRATOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE LATITUDES; TROPICS; MODEL AB A trajectory calculation is used to compare the characteristic time for northern midlatitude aircraft emissions to disperse during both summer and winter. The mixing process is summarized by the time evolution of the ''mixing entropy,'' which is proportional to the number of ways of partitioning N parcels over M equal area subregions of the hemisphere. The mixing entropy is a measure of the disorder in the parcel distribution and quantifies the approach to a spatially uniform state as time increases. We show that the time for a single release of exhaust to become mixed down to length scales of the order of 800 km is about 2 months in winter and at least 4 months in summer. We also examine the time evolution of the mixing entropy of emissions from a continuous source over two 6-month periods starting in January and June. For a single continuous source, which represents a persistent and highly asymmetric perturbation, we find that the horizontal distribution of the total emissions reaches a mixing steady state in 6-8 months. On this timescale the mixing entropy is close to the maximum value, and the likelihood of large temporal fluctuations becomes small. The dependence of the mixing on the location of the source and the effect of multiple flight paths on the overall uniformity of the spatial distribution is also considered. C1 HUGHES STX, LANHAM, MD USA. RP SPARLING, LC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 916, GREENBELT, MD 20771 USA. NR 21 TC 7 Z9 7 U1 0 U2 0 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 AUG 20 PY 1995 VL 100 IS D8 BP 16805 EP 16812 DI 10.1029/95JD01647 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700040 ER PT J AU KUMAR, CK SWAMINATHAN, PK ANDERSON, DE YEE, JH GUNSON, MR ABRAMS, MC AF KUMAR, CK SWAMINATHAN, PK ANDERSON, DE YEE, JH GUNSON, MR ABRAMS, MC TI ATMOS-ATLAS-1 MEASUREMENTS OF THERMOSPHERIC AND MESOSPHERIC NITRIC-OXIDE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The atmospheric trace molecule spectroscopy (ATMOS) instrument obtained solar occultation spectra of the terrestrial atmosphere during the Atmospheric Laboratory for Applications and Science (ATLAS 1) mission of March 26-April 4, 1992. During this time, A(p) varied between 11 and 18 while the F-10.7 index was near 192. The analyses of the 5.3-mu m spectral data to derive nitric oxide densities in the lower thermosphere and mesosphere are described here. The results show that a peak NO density of 1.0 x 10(8) cm(-3) occurs at 105 +/- 2.5 km for the latitude range 38 degrees N-58 degrees S. The density values are higher than previously reported using UV measurements. These measurements worsen the discrepancy with photochemical models at low latitudes where models already underpredict nitric oxide. C1 HOWARD UNIV, CTR STUDY TERR & EXTRA TERR ATMOSPHERES, WASHINGTON, DC 20059 USA. JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MD USA. CALTECH, JET PROP LAB, PASADENA, CA USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. RI Swaminathan, Pazhayannur/I-3609-2012 OI Swaminathan, Pazhayannur/0000-0003-1272-9694 NR 17 TC 8 Z9 8 U1 0 U2 0 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 AUG 20 PY 1995 VL 100 IS D8 BP 16839 EP 16846 DI 10.1029/95JD01542 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700043 ER PT J AU GLEASON, JF MCPETERS, R AF GLEASON, JF MCPETERS, R TI THE NIMBUS-7 SOLAR BACKSCATTER ULTRAVIOLET DATA IN THE NONSYNC PERIOD (FEBRUARY 1987 TO JUNE 1990) (VOL 100, PG 16873, 1995) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Correction ID OZONE RP GLEASON, JF (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, ATMOSPHER CHEM & DYNAM BRANCH, MAIL CODE 916, GREENBELT, MD 20771 USA. RI Gleason, James/E-1421-2012; McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 7 TC 10 Z9 10 U1 0 U2 0 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 AUG 20 PY 1995 VL 100 IS D8 BP 16873 EP 16877 DI 10.1029/95JD01530 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RU107 UT WOS:A1995RU10700048 ER PT J AU FRANCISCO, JS SANDER, SP AF FRANCISCO, JS SANDER, SP TI AB-INITIO PREDICTION OF THE BARRIER HEIGHT FOR ABSTRACTION OF HYDROGEN FROM H2O2 BY CLO RADICAL SO MOLECULAR PHYSICS LA English DT Article ID OZONE; STRATOSPHERE AB The reaction of ClO radicals with H2O2 has been investigated by ab initio molecular orbital theory with a variety of basis sets and levels of correlation. At the QCISD(T)/6-311 + + G(2df,2p) level of theory the heat of reaction for ClO + H2O2 is -8.4 +/- 2 kcal mol(-1) and the classical barrier height is 7.6 +/- 2 kcal mol(-1). C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 8 TC 3 Z9 3 U1 0 U2 1 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD AUG 20 PY 1995 VL 85 IS 6 BP 1069 EP 1071 DI 10.1080/00268979500101671 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RV614 UT WOS:A1995RV61400003 ER PT J AU RYU, SO HWANG, SM RABINOWITZ, MJ AF RYU, SO HWANG, SM RABINOWITZ, MJ TI RATE COEFFICIENT OF THE O+H-2=OH+H REACTION DETERMINED VIA SHOCK-TUBE LASER-ABSORPTION SPECTROSCOPY SO CHEMICAL PHYSICS LETTERS LA English DT Article ID LASER-ABSORPTION SPECTROSCOPY; RATE CONSTANTS; SHOCK-TUBE; RESONANCE-ABSORPTION; O+H2->OH+H; H-2; MIXTURES; O(P-3); D2; O+D2->OD+D AB The rate coefficient for the reaction O + H-2 = OH + H was determined via OH profile measurements in a lean H-2/O-2/Ar mixture behind reflected shock waves. Over the temperature range 1424-2427 K our expression is k(2) = (1.88 +/- 0.07) X 10(14) exp(- 6897 +/- 53 K/T) cm(3) mol(-1) s(-1). We do not support strong curvature in the rate expression for this temperature range. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP RYU, SO (reprint author), UNIV TOLEDO,DEPT CHEM ENGN,TOLEDO,OH 43606, USA. NR 27 TC 20 Z9 20 U1 1 U2 7 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 AUG 18 PY 1995 VL 242 IS 3 BP 279 EP 284 DI 10.1016/0009-2614(95)00733-K PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RR076 UT WOS:A1995RR07600006 ER PT J AU AKAPO, SO AF AKAPO, SO TI CHARACTERIZATION OF MICROPACKED ALKYL-BONDED SILICA COLUMNS FOR GAS-CHROMATOGRAPHIC ANALYSES OF LIGHT-HYDROCARBONS IN PLANETARY-ATMOSPHERES SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article ID MOLECULAR-WEIGHT HYDROCARBONS; PLOT CAPILLARY COLUMN; TITANS ATMOSPHERE; NITRILES; SEPARATION; PHASES AB Micropacked columns of different types of chemically bonded n-octyl- and n-octadecyl stationary phases were prepared and evaluated for the separation of light hydrocarbons under isothermal conditions. Column selectivities and efficiencies varied with surface coverage and the functionality of the silanizing agents. As might be expected, solute retentions are higher on the C-18 phases than on the C-8 phases due to the increased effective interactive surface between the solute and the stationary phase. Among the phases examined, the polymeric n-octadecyl packings gave the highest plate number and better retention characteristics for the test solutes. The H versus (u) over bar plots obtained revealed the applicability of the columns for fast analysis at low linear carrier-gas velocities and correspondingly low volumetric flow-rates without any substantial loss in efficiency. Within the temperature range investigated, thermal-stability experiments indicate that the polymeric n-octadecyl phase can be used at temperatures up to 250 degrees C with little or no column bleed. RP AKAPO, SO (reprint author), NASA,AMES RES CTR,MAIL STOP 239-12,MOFFETT FIELD,CA 94035, USA. NR 31 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD AUG 18 PY 1995 VL 709 IS 2 BP 291 EP 301 DI 10.1016/0021-9673(95)00479-7 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA RT436 UT WOS:A1995RT43600008 ER PT J AU SMITH, DE LEMOINE, F ZUBER, MT AF SMITH, DE LEMOINE, F ZUBER, MT TI SIMULTANEOUS ESTIMATION OF THE MASSES OF MARS, PHOBOS, AND DEIMOS USING SPACECRAFT DISTANT ENCOUNTERS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ASTROMETRIC OBSERVATIONS; SATELLITES; ASTEROIDS; SURFACE; GRAVITY; MODEL; WATER AB The masses of Mars and its satellites, Phobos and Deimos, have been estimated from the Mariner 9 and Viking 1 and 2 Orbiter tracking data. These spacecraft were sensitive to the gravitational force of Mars as well as to its satellites. Although the satellite masses are eight orders of magnitude smaller than Mars, their regular effect on the orbits of the spacecraft is evident in the tracking data and has enabled us to derive their masses simultaneously with that of Mars. Our method for estimating the satellite masses uses the many ''distant encounters'' of the spacecraft with these small bodies rather than the few ''close encounters'' used in previous studies. The mass estimate for Phobos leads to a mean density of 1530+/-100 kg m(-3) based on a volume of 5748+/-190 km(3) (Thomas, 1993), while the mass estimate of Deimos leads to a poorly constrained mean density of 1340+/-828 kg m(-3) based on a volume of 1017+/-130 km(3) (Thomas, 1993). Our analysis confirms, within the bounds of error, the anomalously low density of Phobos using an independent method and data set. If the result is valid within several times the estimated error (1 sigma), then factors other than composition, i.e., porosity, a thick regolith and/or a significant interior ice content, are required to explain the observed mass of this body. C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. JOHNS HOPKINS UNIV,DEPT EARTH & PLANETARY SCI,BALTIMORE,MD 21218. RP SMITH, DE (reprint author), UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742, USA. RI Lemoine, Frank/D-1215-2013 NR 27 TC 30 Z9 30 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 15 PY 1995 VL 22 IS 16 BP 2171 EP 2174 DI 10.1029/95GL01801 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RT333 UT WOS:A1995RT33300024 ER PT J AU RAY, RD BETTADPUR, S EANES, RJ SCHRAMA, EJO AF RAY, RD BETTADPUR, S EANES, RJ SCHRAMA, EJO TI GEOMETRICAL DETERMINATION OF THE LOVE NUMBER H(2) AT 4 TIDAL FREQUENCIES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTH; TIDES AB The Love number h(2) is determined at the M(2), N-2, O-1, and K-1 frequencies by combining satellite altimetry with in situ ocean tidal measurements. Topex/Poseidon altimetry is used to measure the (ocean + earth) tide, while gauges at 114 island and ocean-bottom sites determine the ocean tide; the difference sets constraints on h(2). Our h(2) standard errors are somewhat larger than recent VLBI estimates, but they clearly delineate the resonance in K-1 at the 6-sigma level. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. DELFT UNIV TECHNOL, FAC GEODET ENGN, 2629 JA DELFT, NETHERLANDS. RP UNIV TEXAS, CTR SPACE RES, AUSTIN, TX 78712 USA. RI Ray, Richard/D-1034-2012; Bettadpur, Srinivas/M-3744-2014 NR 20 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 15 PY 1995 VL 22 IS 16 BP 2175 EP 2178 DI 10.1029/95GL01809 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RT333 UT WOS:A1995RT33300025 ER PT J AU LUNDGREN, P GIARDINI, D AF LUNDGREN, P GIARDINI, D TI THE JUNE 9 BOLIVIA AND MARCH 9 FIJI DEEP EARTHQUAKES OF 1994 .1. SOURCE PROCESSES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COMPLEX BODY WAVES; ITERATIVE DECONVOLUTION; GREAT EARTHQUAKES; MOMENT TENSOR; P-WAVES; DEFORMATION; SEISMICITY; INVERSION; MODES AB We examined the source characteristics of the 1994 deep earthquakes of Bolivia (June 9) and Fiji (March 9) over a period range of 1-1000 s using moment tenser and body wave analyses. Moment tenser inversions from 100-1000 s reveal that these two earthquakes were essentially point sources at very long period with insignificant isotropic and non-double couple components with scalar moments M(o), = 2.56x10(21) Nm for the Bolivia and M(o) = 0.26x10(21) Nm for the Fiji earthquakes. Body wave analysis for the Bolivia event reveals a 45 s duration, a nearly linear E-NE 1 km/s rupture on the subhorizontal focal mechanism plane giving a stress drop Delta sigma = 114 MPa. For the Fiji earthquake we find a change in focal mechanism and a linear 3 km/s rupture plunging shallowly to the north on the steep dipping nodal plane with a duration of at least 20 s and Delta sigma = 14 MPa. Both ruptures propagated parallel their null (sigma(2)) axis and suggests that their width is controlled by the thickness of the seismogenic volume in deep slabs. C1 UNIV ROME 3,DIPARTIMENTO SCI GEOL,I-00154 ROME,ITALY. RP LUNDGREN, P (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Giardini, Domenico/F-5406-2011 NR 21 TC 20 Z9 20 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 15 PY 1995 VL 22 IS 16 BP 2241 EP 2244 DI 10.1029/95GL02233 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RT333 UT WOS:A1995RT33300042 ER PT J AU MARTIN, JML LEE, TJ TAYLOR, PR FRANCOIS, JP AF MARTIN, JML LEE, TJ TAYLOR, PR FRANCOIS, JP TI THE ANHARMONIC-FORCE FIELD OF ETHYLENE, C2H4, BY MEANS OF ACCURATE AB-INITIO CALCULATIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID STRETCHING VIBRATIONAL MANIFOLDS; 1ST PRINCIPLES COMPUTATION; CONFIGURATION-INTERACTION; WAVE-FUNCTIONS; BASIS-SETS; THERMOCHEMICAL PROPERTIES; HARMONIC APPROXIMATION; MOLECULAR CALCULATIONS; TRIPLE EXCITATIONS; INFRARED-SPECTRUM AB The quartic force field of ethylene, C2H4, has been calculated ab initio using augmented coupled cluster, CCSD(T), methods and correlation consistent basis sets of spdf quality. For the C-12 isotopomers C2H4, C2H3D, H2CCD2, cis-C2H2D2, trans-C2H2D2, C2HD3, and C2D4, all fundamentals are reproduced to better than 10 cm(-1), except for three cases where the error is 11 cm(-1). Our calculated harmonic frequencies suggest a thorough revision of the accepted cm experimentally derived values. Our computed and empirically corrected r(e) geometry differs substantially from experimentally derived values: Both the predicted r(z) geometry and the ground-state rotational constants are, however, in excellent agreement with experiment, suggesting revision of the older values. Anharmonicity constants agree well with experiment for stretches, but differ substantially for stretch-bend interaction constants, due to equality constraints in the experimental analysis that do not hold. Improved criteria for detecting Fermi and Coriolis resonances are proposed and found to work well, contrary to the established method based on harmonic frequency differences that fails to detect several important resonances for C2H4 and its isotopomers. Surprisingly good results are obtained with a small spd basis at the CCSD(T) level. The well-documented strong basis set effect on the v(8) out-of-plane motion is present to a much lesser extent when correlation-optimized polarization functions are used. Complete sets of anharmonic, rovibrational coupling, and centrifugal distortion constants for the isotopomers are available as supplementary material to the paper via the World-Wide Web. (C) 1995 American Institute of Physics. C1 UNIV INSTELLING ANTWERP, INST MAT SCI, DEPT CHEM, B-2610 WILRIJK, BELGIUM. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. SAN DIEGO SUPERCOMP CTR, SAN DIEGO, CA 92186 USA. RP MARTIN, JML (reprint author), LIMBURGS UNIV CENTRUM, DEPT SBG, UNIV CAMPUS, B-3590 DIEPENBEEK, BELGIUM. RI Lee, Timothy/K-2838-2012; Martin, Jan/A-7457-2008 OI Martin, Jan/0000-0002-0005-5074 NR 85 TC 257 Z9 258 U1 4 U2 28 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 1995 VL 103 IS 7 BP 2589 EP 2602 DI 10.1063/1.469681 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RP455 UT WOS:A1995RP45500022 ER PT J AU HOLDZKOM, JJ HOOKER, SB KIRWAN, AD AF HOLDZKOM, JJ HOOKER, SB KIRWAN, AD TI A COMPARISON OF A HYDRODYNAMIC LENS MODEL TO OBSERVATIONS OF A WARM-CORE RING SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID POTENTIAL VORTICITY; 82B; STRAIN AB Analysis of advanced very high resolution radiometer satellite images has shown long-period fluctuations in ring eccentricity for 82-B. Concurrent shipboard measurements as well as satellite data also suggest that this anticyclonic ring was often paired with one or more cyclonic eddies. Furthermore, satellite image analysis and recent numerical simulations suggest strong deformation in the fluid between the anticyclone and the cyclone. The purpose here is to investigate a causal relation between the time dependent environmental deformation and the eccentricity fluctuations. To this end, we attempt to parameterize the effects of the cyclone as environmental forcing on the anticyclone using a nonlinear, non-quasi-geostrophic, hydrodynamic lens model. Our results suggest that the strong deformation in the environmental flow could be responsible for long-period fluctuations in eccentricity. Other model ring features, such as spin (vorticity/2) and rotation rate of 82-B, are discussed and compared to observations. Another significant feature of the model results is the presence of superinertial frequencies in the solution fields. Since current mesoscale observation techniques are unable to resolve such high frequencies, it is unknown whether or not this result is realistic. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOLDZKOM, JJ (reprint author), OLD DOMINION UNIV,CTR COASTAL PHYS OCEANOG,CRITTENTON HALL,NORFOLK,VA 23529, USA. RI Hooker, Stanford/E-2162-2012 NR 24 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD AUG 15 PY 1995 VL 100 IS C8 BP 15889 EP 15897 DI 10.1029/95JC00966 PG 9 WC Oceanography SC Oceanography GA RP999 UT WOS:A1995RP99900007 ER PT J AU MARTIN, GM JOHNSON, DW ROGERS, DP JONAS, PR MINNIS, P HEGG, DA AF MARTIN, GM JOHNSON, DW ROGERS, DP JONAS, PR MINNIS, P HEGG, DA TI OBSERVATIONS OF THE INTERACTION BETWEEN CUMULUS CLOUDS AND WARM STRATOCUMULUS CLOUDS IN THE MARINE BOUNDARY-LAYER DURING ASTEX SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID AIRCRAFT OBSERVATIONS; WATER CLOUDS; MODEL; ENTRAINMENT; PARAMETERIZATION; SATELLITE; TURBULENT; FIRE AB Decoupling of the marine boundary layer beneath stratocumulus clouds and the formation of cumulus clouds at the top of a surface-based mixed layer (SML) have frequently been observed and modeled. When such cumulus clouds penetrate the overlying stratocumulus layer, the cloud microphysics and hence the radiative properties of the cloud are altered locally. Observations made during a series of Lagrangian experiments in the Azores as part of the Atlantic Stratocumulus Transition Experiment (ASTEX, June 1992) have been analyzed to ascertain how the properties of a stratocumulus layer with which cumulus clouds are interacting differ from those of an unaffected cloud layer. The results suggest that in regions where cumulus clouds penetrate the cloud layer, the stratocumulus is thickened as the cumuli spread out into its base. Transport of air from the SML into the cloud by convective updrafts is observed, and the increase in available moisture within the penetrating cumulus clouds results in increased liquid water content and hence changes in the droplet size spectra. The greater liquid water path results in a larger cloud optical depth, so that regions where cumulus are interacting with the stratocumulus layer can be observed in satellite measurements. Therefore, it is likely that the surface energy budget may be significantly altered by this process, and it may be necessary to parameterize these effects in large-scale numerical models. C1 SCRIPPS INST OCEANOG,LA JOLLA,CA. UNIV MANCHESTER,INST SCI & TECHNOL,DEPT ATMOSPHER PHYS,MANCHESTER M60 1QD,LANCS,ENGLAND. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195. RP MARTIN, GM (reprint author), METEOROL OFF,METEOROL RES FLIGHT,DRA,BLDG Y46,FARNBOROUGH GU14 6TD,HANTS,ENGLAND. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 42 TC 42 Z9 44 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 15 PY 1995 VL 52 IS 16 BP 2902 EP 2922 DI 10.1175/1520-0469(1995)052<2902:OOTIBC>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RN655 UT WOS:A1995RN65500016 ER PT J AU PLATNICK, S VALERO, FPJ AF PLATNICK, S VALERO, FPJ TI VALIDATION OF A SATELLITE CLOUD RETRIEVAL DURING ASTEX SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SOLAR-RADIATION MEASUREMENTS; EFFECTIVE PARTICLE RADIUS; ATMOSPHERIC CORRECTIONS; MARINE STRATOCUMULUS; OPTICAL-THICKNESS; LIGHT-SCATTERING; LIQUID WATER; CALIBRATION; ABSORPTION; AIRCRAFT AB An algorithm using NOAA-12 AVHRR (Advanced Very High Resolution Radiometer) solar reflectance measurements for retrieving cloud droplet size and optical thickness has been applied to a boundary layer stratocumulus cloud in the vicinity of the Azores on 12 June 1992 during the Atlantic Stratocumulus Transition Experiment (ASTEX). This day was particularly advantageous for validations because of the absence of cirrus or other higher-level clouds during the satellite overpass and the existence of a large relatively uniform stratus cloud deck. Uncertainty estimates for the retrievals are presented dong with a discussion of the algorithm. An in-flight absolute calibration of AVHRR channel 1, necessary for accurate optical thickness retrievals, was done concurrently with the retrievals through comparison with a visible radiometer flown on the National Aeronautics and Space Administration's ER-2 and using the stratus cloud as the common reflectance target. Results are compared with in situ microphysical measurements taken with the Particulate Volume Monitor (PVM-100) and Forward Scattering Spectrometer Probe (FSSP-100) instruments on the University of Washington C-131A aircraft. Satellite retrievals of both optical thickness and droplet size lie within the values measured by the two in situ instruments. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,CALIF SPACE INST,LA JOLLA,CA 92093. RI Platnick, Steven/J-9982-2014 OI Platnick, Steven/0000-0003-3964-3567 NR 48 TC 85 Z9 89 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 15 PY 1995 VL 52 IS 16 BP 2985 EP 3001 DI 10.1175/1520-0469(1995)052<2985:AVOASC>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RN655 UT WOS:A1995RN65500022 ER PT J AU CAHALAN, RF SILBERSTEIN, D SNIDER, JB AF CAHALAN, RF SILBERSTEIN, D SNIDER, JB TI LIQUID WATER PATH AND PLANE-PARALLEL ALBEDO BIAS DURING ASTEX SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATION BUDGET EXPERIMENT; CLOUD FIELDS; PARAMETERIZATION AB Inhomogeneous distributions of liquid water like those observed in real clouds generally reflect less solar radiation than idealized uniform distributions assumed in plane-parallel theory. Here the authors determine cloud reflectivity and the associated plane-parallel albedo bias from distributions of liquid water path derived from 28 days of microwave radiometer measurements obtained on Porto Santo Island in the Madeiras during June 1992 as part of the Atlantic Stratocumulus Transition Experiment (ASTEX). The distributions are determined for each hour of the day, both for composites of the full set of 28 days and for a subset of 8 days having a high fraction of relatively thick cloud. Both sets are compared with results obtained from California stratocumulus during FIRE [First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment]. In FIRE the albedo bias was dominated by the variability of the cloud optical depth, as measured by a fractal parameter, 0 less than or equal to f less than or equal to 1, while the ASTEX results are more complex. Mean cloud fraction above a 10 g m(-2) threshold is about 50% in the 28-day set, compared to 76% in the 8-day subset and 82% in FIRE, Cloud fraction is sensitive to the threshold for the 28 ASTEX days, probably due to a large fraction of thin cloud below the threshold, but this is not the case for the 8-day subset or for FIRE. Clear fractions during ASTEX are generally of shorter duration than those in FIRE, as are those in the 8-day subset. The diurnal mean fractal parameter is about 0.6 in ASTEX compared to 0.5 in FIRE, while the 8-day subset has nearly the same mean but a wider range. The diurnal cycle in cloud albedo and albedo bias is computed from the cloud parameters for both sets, assuming zero clear-sky albedo. The total absolute albedo bias rises to values above 0.3 at sunrise and sunset, but since there is little incident energy at that time, the reflected flux is more affected by the midday bias. The total albedo bias has a 1000 LST maximum of about 0.3, largely due to a cloud fraction contribution of 0.2, absent in FIRE because in that case cloud fraction remains near 100% until after 1000 LST. The albedo bias has a second maximum of about 0.2 at noon, again mainly from cloud fraction, and then drops to a minimum of about 0.1 at 1400 LST, when cloud fraction and fractal structure contribute about equally. Finally, a third maximum due to cloud fraction occurs at 1600 LST. In the 8-day subset, the 1000 LST maximum becomes dominated by the fractal structure, since the cloud fraction remains near 100% until 1000 LST, as in FIRE. The noon maximum receives roughly equal contributions, while the 1400 LST minimum bias is mainly due to fractal structure. Finally, the 1600 LST maximum and the evening limb bias are similar to those of the full 28-day set. These results show that cloud fractal and radiative properties can vary considerably from one site and time to another, and at different times within the same site, as meteorological conditions change. C1 HUGHES STX,LANHAM,MD. NOAA,ENVIRONM RES LAB,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. RP CAHALAN, RF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 913,GREENBELT,MD 20771, USA. RI Cahalan, Robert/E-3462-2012 OI Cahalan, Robert/0000-0001-9724-1270 NR 30 TC 37 Z9 37 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 15 PY 1995 VL 52 IS 16 BP 3002 EP 3012 DI 10.1175/1520-0469(1995)052<3002:LWPAPP>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RN655 UT WOS:A1995RN65500023 ER PT J AU GOLLMER, SM HARSHVARDHAN CAHALAN, RF SNIDER, JB AF GOLLMER, SM HARSHVARDHAN CAHALAN, RF SNIDER, JB TI WINDOWED AND WAVELET ANALYSIS OF MARINE STRATOCUMULUS CLOUD INHOMOGENEITY SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ANGLE RADIATIVE-TRANSFER; ATMOSPHERES; DIFFUSION; SPECTRA; MEDIA; RAIN AB To improve radiative transfer calculations for inhomogeneous clouds, a consistent means of modeling inhomogeneity is needed. One current method of modeling cloud inhomogeneity is through the use of fractal parameters. This method is based on the supposition that cloud inhomogeneity over a large range of scales is related. An analysis technique named wavelet analysis provides a means of studying the multiscale nature of cloud inhomogeneity. In this paper, the authors discuss the analysis and modeling of cloud inhomogeneity through the use of wavelet analysis. Wavelet analysis as well as other windowed analysis techniques are used to study liquid water path (LWP) measurements obtained during the marine stratocumulus phase of the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment. Statistics obtained using analysis windows, which are translated to span the LWP dataset, are used to study the focal (small scale) properties of the cloud field as well as their time dependence. The LWP data are transformed onto an orthogonal wavelet basis that represents the data as a number of times series. Each of these time series lies within a frequency band and has a mean frequency that is half the frequency of the previous band. Wavelet analysis combined with translated analysis windows reveals that the local standard deviation of each frequency band is correlated with the local standard deviation of the other frequency bands. The ratio between the standard deviation of adjacent frequency bands is 0.9 and remains constant with respect to time. This ratio defined as the variance coupling parameter is applicable to ail of the frequency bands studied and appears to be related to the slope of the data's power spectrum. Similar analyses are performed on two cloud inhomogeneity models, which use fractal-based concepts to introduce inhomogeneity into a uniform cloud field. The bounded cascade model does this by iteratively redistributing LWP at each scale using the value of the local mean. This model is reformulated into a wavelet multiresolution framework, thereby presenting a number of variants of the bounded cascade model. One variant introduced in this paper is the ''variance coupled model,'' which redistributes LWP using the local standard deviation and the variance coupling parameter. While the bounded cascade model provides an elegant two-parameter model for generating cloud inhomogeneity, the multiresolution framework provides more flexibility at the expense of model complexity. Comparisons are made with the results from the LWP data analysis to demonstrate both the strengths and weaknesses of these models. C1 PURDUE UNIV,DEPT EARTH & ATMOSPHER SCI,W LAFAYETTE,IN 47907. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. NOAA,ENVIRONM RES LAB,ENVIRONM TECHNOL LAB,BOULDER,CO 80303. RP GOLLMER, SM (reprint author), CEDARVILLE COLL,DEPT SCI & MATH,POB 601,CEDARVILLE,OH 45314, USA. RI Cahalan, Robert/E-3462-2012 OI Cahalan, Robert/0000-0001-9724-1270 NR 34 TC 12 Z9 12 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 15 PY 1995 VL 52 IS 16 BP 3013 EP 3030 DI 10.1175/1520-0469(1995)052<3013:WAWAOM>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RN655 UT WOS:A1995RN65500024 ER PT J AU CHEN, PS SANDERS, JH LIAW, YK AF CHEN, PS SANDERS, JH LIAW, YK TI DUCTILITY DEGRADATION OF VACUUM-PLASMA-SPRAYED NARLOY-Z AT ELEVATED-TEMPERATURES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE VACUUM PLASMA SPRAYING; NARLOY-Z; DUCTILITY; AEROSPACE COMPONENTS ID ISOSTATIC PRESSING DIAGRAMS; COPPER; OXYGEN AB Vacuum plasma spray forming is being used in the near-net fabrication of aerospace components at the Marshall Space Flight Center (MSFC), Alabama. For example, vacuum-plasma-sprayed (VPS) NARloy-Z (a copper-based alloy with high thermal conductivity) is used to form the combustion chamber liner of liquid rocket engines. VPS NARloy-Z possesses properties comparable with the wrought alloy at temperatures ranging from - 259 to 316 degrees C. However, VPS material exhibits lower ductility than the wrought material at chamber operating temperatures (ranging from 427 to 649 degrees C). Because of these findings, an investigation was initiated into the mechanisms responsible for the loss of high-temperature ductility. Fracture analysis indicated that ductility loss at elevated temperatures is associated with a transition in fracture mode from transgranular to intergranular. Low-ductility specimens featured extensive grain boundary cavitation with limited grain elongation in the stress direction. Grain size also influenced the high-temperature ductility; finer grained material is more ductile. VPS NARloy-Z had more cavities at grain boundaries and a higher bulk oxygen content than wrought NARloy-Z. The ductility loss at high temperatures appears to have been caused by compounding effects of excessive oxygen and grain boundary cavitation. High-temperature ductility was improved by altering the thermal processing (pre-hot isostatic pressing (HIP) vacuum anneal, HIP and post-HIP vacuum aging) to reduce oxygen and enhance grain boundary integrity. C1 ROCKWELL INT CORP,DIV ROCKETDYNE,HUNTSVILLE,AL 35806. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAT & PROC LAB,MET PROC BRANCH,HUNTSVILLE,AL 35812. RP CHEN, PS (reprint author), GEORGE C MARSHALL SPACE FLIGHT CTR,MET RES FACILIT,IIT,RES INST,HUNTSVILLE,AL 35812, USA. NR 14 TC 8 Z9 8 U1 3 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD AUG 15 PY 1995 VL 199 IS 2 BP 145 EP 152 DI 10.1016/0921-5093(94)09710-0 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA RV344 UT WOS:A1995RV34400004 ER PT J AU ICHIGE, M BEN, S CRAWFORD, HJ DOKE, T ENGELAGE, JM FLORES, I GREINER, L HAYASHI, T KASHIWAGI, T KIKUCHI, J KOBAYASHI, M MASUDA, K MOZUMDER, A MITCHELL, JW SHIBAMURA, E TAKASHIMA, T TULL, CE AF ICHIGE, M BEN, S CRAWFORD, HJ DOKE, T ENGELAGE, JM FLORES, I GREINER, L HAYASHI, T KASHIWAGI, T KIKUCHI, J KOBAYASHI, M MASUDA, K MOZUMDER, A MITCHELL, JW SHIBAMURA, E TAKASHIMA, T TULL, CE TI ANALYSIS OF DATA OBTAINED WITH AU IONS OF 700 MEV/N ENERGY IN AN ALLENE-DOPED LIQUID AR HOMOGENEOUS CALORIMETER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ARGON CALORIMETER; HEAVY-IONS; SCINTILLATION; IONIZATION; RESOLUTION; PARTICLES AB A new allene-doped liquid argon homogeneous calorimeter has been constructed for measurement of energies of relativistic heavy ions, its electrode system consists of thin multi-parallel plates and it has been tested for relativistic Au ions from Bevalac at LBL. The results are compared with those obtained by simulation, including ''quenching factor'', ''positive ion effect'' and ''electron attachment to electronegative impurities''. The pattern shown in Delta E-E scatter plots, obtained from the multi-parallel plate electrode calorimeter, is in good agreement with those obtained by simulation, but the energy resolution for An ions is three times or more worse than that of the simulation. At present the reason for the difference is not clear By simulation, it is shown that the identification of adjacent charges or isotopes is possible for relativistic Na, Fe and La ions stopped in the calorimeter, using signals both from the cell. in which ions stopped and from the preceding cell. C1 SAITAMA COLL HLTH,URAWA,SAITAMA 338,JAPAN. WASEDA UNIV,ADV RES CTR SCI & ENGN,SHINJUKU KU,TOKYO 169,JAPAN. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. KANAGAWA UNIV,FAC ENGN,KANAGAWA KU,YOKOHAMA,KANAGAWA 221,JAPAN. UNIV NOTRE DAME,RADIAT LAB,NOTRE DAME,IN 46556. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. NR 17 TC 3 Z9 3 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 AUG 15 PY 1995 VL 362 IS 2-3 BP 506 EP 516 DI 10.1016/0168-9002(95)00317-7 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA RP777 UT WOS:A1995RP77700032 ER PT J AU TINTO, M ESTABROOK, FB AF TINTO, M ESTABROOK, FB TI PARALLEL BEAM INTERFEROMETRIC DETECTORS OF GRAVITATIONAL-WAVES SO PHYSICAL REVIEW D LA English DT Article AB We discuss interferometric detection of gravitational waves using multiple bounce parallel beam systems. We consider as an example the simplest design that allows us to remove the laser frequency fluctuations, and yet gives a remaining nonzero gravitational wave signal, viz., an antiparallel pair of folded beams. The resultant sensitivity, however, is about B times smaller than the sensitivity of a two-arm Michelson interferometer optimally operating with B reflections, We have calculated other, less symmetrical, designs with similar results. Parallel beam interferometric detectors could possibly be preferred for engineering reasons, site availability, and simplicity of response. RP TINTO, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 17 TC 10 Z9 10 U1 0 U2 0 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 AUG 15 PY 1995 VL 52 IS 4 BP 1749 EP 1754 DI 10.1103/PhysRevD.52.1749 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RQ554 UT WOS:A1995RQ55400003 ER PT J AU COPELAND, EJ GLEISER, M MULLER, HR AF COPELAND, EJ GLEISER, M MULLER, HR TI OSCILLONS - RESONANT CONFIGURATIONS DURING BUBBLE COLLAPSE SO PHYSICAL REVIEW D LA English DT Article ID ELECTROWEAK PHASE-TRANSITION; SUBCRITICAL BUBBLES; FALSE VACUUM; NONTOPOLOGICAL SOLITONS; WAVE-EQUATIONS; DIMENSIONS; DYNAMICS; PULSONS; KINK; FATE AB Oscillons are localized, nonsingular, time-dependent, spherically symmetric solutions of nonlinear scalar field theories which, although unstable, are extremely long lived. We show that they naturally appear during the collapse of subcritical bubbles in models with symmetric and asymmetric double-well potentials. By a combination of analytical and numerical work we explain several of their properties, including the conditions for their existence, their longevity, and their final demise. We discuss several contexts in which we expect oscillons to be relevant. In particular, their nucleation during cosmological phase transitions may have wide-ranging consequences. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. DARTMOUTH COLL,DEPT PHYS & ASTRON,HANOVER,NH 03755. RP COPELAND, EJ (reprint author), UNIV SUSSEX,SCH MATH & PHYS SCI,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. NR 39 TC 107 Z9 108 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 AUG 15 PY 1995 VL 52 IS 4 BP 1920 EP 1933 DI 10.1103/PhysRevD.52.1920 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RQ554 UT WOS:A1995RQ55400015 ER PT J AU KOSOWSKY, A TURNER, MS AF KOSOWSKY, A TURNER, MS TI CBR ANISOTROPY AND THE RUNNING OF THE SCALAR SPECTRAL INDEX SO PHYSICAL REVIEW D LA English DT Note ID INFLATIONARY UNIVERSE; PERTURBATIONS AB Accurate (less than or equal to 1%) predictions for the anisotropy of the cosmic background radiation (CBR) are essential for using future high-resolution (less than or equal to 1 degrees) CBR maps to test cosmological models. In many inflationary models the variation (''running'') of the spectral index of the spectrum of density perturbations is a significant effect and leads to changes of around 1-10% in the CBR power spectrum. We propose a general method for taking running into account which uses the derivative of the spectral index (dn/dlnk). Conversely, high-resolution CBR maps may be able to determine dn/dlnk, giving important information about the inflationary potential. C1 HARVARD UNIV,LYMAN LAB PHYS,DEPT PHYS,CAMBRIDGE,MA 02138. UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP KOSOWSKY, A (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 27 TC 188 Z9 188 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 AUG 15 PY 1995 VL 52 IS 4 BP R1739 EP R1743 DI 10.1103/PhysRevD.52.R1739 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RQ554 UT WOS:A1995RQ55400001 ER PT J AU SMITH, GD JAFFE, RL YOON, DY AF SMITH, GD JAFFE, RL YOON, DY TI CONFORMATIONS OF PERFLUOROPOLY(OXYETHYLENE) FROM AB-INITIO ELECTRONIC-STRUCTURE CALCULATIONS ON MODEL MOLECULES SO MACROMOLECULES LA English DT Article ID 1,2-DIMETHOXYETHANE AB The conformational characteristics of perfluoropoly(oxyethylene) (PFPOE) chains have been investigated in detail, based upon ab initio electronic structure calculations on the model molecules perfluorodiethyl ether and perfluoro-1,2-dimethoxyethane, and have also been compared with those of poly(oxyethylene) (POE) and poly(tetrafluoroethylene) (PTFE). The C-C-O-C bond exhibits split trans conformations, similar to those for the C-C-C-C bond in PTFE, which are strongly favored over the gauche state by 2.5 kcal/mol. In contrast, O-C-C-O bond shows no splitting for the trans or gauche conformations due to the absence of pendant fluorine atoms on the oxygen atoms, and favors a gauche conformation over the trans state by about 0.2 kcal/mol, according to MP2 level ab initio calculations using a D95+* basis set. This oxygen gauche effect, coupled with an expanded C-O-C skeletal angle of 122 degrees, results in a relatively small predicted random coil dimension for PFPOE with a characteristic ratio of C-infinity approximate to 3.9 at 300 K. Within the limits of ab initio values for the conformational energies and geometries, the predicted value is in good agreement with experimental results of about 4.9. C1 NASA,AMES RES CTR,INST THERMOSCI,MOFFETT FIELD,CA 94035. IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. NR 13 TC 22 Z9 23 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD AUG 14 PY 1995 VL 28 IS 17 BP 5804 EP 5810 DI 10.1021/ma00121a017 PG 7 WC Polymer Science SC Polymer Science GA RR095 UT WOS:A1995RR09500017 ER PT J AU SMITH, GD YOON, DY JAFFE, RL AF SMITH, GD YOON, DY JAFFE, RL TI LONG-TIME MOLECULAR MOTIONS AND LOCAL CHAIN DYNAMICS IN N-C44H90 MELTS BY MOLECULAR-DYNAMICS SIMULATIONS SO MACROMOLECULES LA English DT Article ID MACROMOLECULAR CHAINS; GLASS-TRANSITION; POLYMER-CHAINS; RELAXATION; ANISOTROPY; LATTICE AB Dynamic properties of n-C44H90 melts have been investigated via molecular dynamics simulations with emphasis on long-time molecular motions and their connection to local chain dynamics. Correlation of conformational transitions is also examined. The model employs an atomistic force field which includes hydrogen atoms explicitly and reproduces the conformational energy surface of n-butane and n-hexane, in good agreement with recent ab initio electronic structure calculations. The simulations yield self-diffusion coefficients which are in good agreement with experiment. However, the monomer friction constants calculated from the self-diffusion coefficients are considerably smaller than estimates from the Rouse model fit of the end-to-end chain vector reorientation and experimental melt viscosities, indicative of the fact that these chains are not long enough to assume Gaussian coils. The local bond vector orientation autocorrelation functions (OACF) exhibit important contributions from long relaxation time modes, resulting in long-time ''tails'' in the OACF. In these cases the OACF can be accurately described only by empirical functions and theoretical models which account for the long relaxation time modes. Relaxation times of the long-time tails for the local bond vector OACF approach those of the end-to-end vector OACF of the C44H90 chains and are due to correlation of the relaxation of the local bond vectors to the relaxation of the chain backbone vectors. The torsional autocorrelation functions also show a long-time component which can be described reasonably by exponential-like decay. The relaxation times for the long-time component of the torsional autocorrelation functions are much shorter than was found for the long-time modes of bond vector OACF, indicative of local dynamic heterogeneities. For conformational transitions, directly correlated transitions are found to occur for the self, second, and fourth neighbors. Moreover, the second-neighbor correlated transitions appear to propagate more or less randomly along the chain. C1 NASA,AMES RES CTR,INST THERMOSCI,MOFFETT FIELD,CA 94035. IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 23 TC 38 Z9 38 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD AUG 14 PY 1995 VL 28 IS 17 BP 5897 EP 5905 DI 10.1021/ma00121a028 PG 9 WC Polymer Science SC Polymer Science GA RR095 UT WOS:A1995RR09500028 ER PT J AU PHILLIPS, NG KOGUT, A AF PHILLIPS, NG KOGUT, A TI FIELD ORDERING AND ENERGY DENSITY IN TEXTURE COSMOLOGY SO PHYSICAL REVIEW LETTERS LA English DT Article ID INFLATIONARY UNIVERSE; GLOBAL TEXTURE; PERTURBATIONS AB We use numerical simulations of the time evolution of global textures to investigate the relationship between ordering dynamics and energy density in an expanding universe. Events in which individual textures become fully wound are rare. The energy density is dominated by the more numerous partially wound configurations, with median neighbor-neighbor alignment <(alpha)over tilde>(rho) similar or equal to 0.44. This verifies the recent supposition that such partially wound configurations should dominate the cosmic microwave background. C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP PHILLIPS, NG (reprint author), UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742, USA. NR 24 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD AUG 14 PY 1995 VL 75 IS 7 BP 1264 EP 1267 DI 10.1103/PhysRevLett.75.1264 PG 4 WC Physics, Multidisciplinary SC Physics GA RN463 UT WOS:A1995RN46300007 ER PT J AU DOWNIE, JD AF DOWNIE, JD TI NONLINEAR COHERENT OPTICAL-IMAGE PROCESSING USING LOGARITHMIC TRANSMITTANCE OF BACTERIORHODOPSIN FILMS SO APPLIED OPTICS LA English DT Article ID NOISE AB The transmission properties of some bacteriorhodopsin-film spatial light modulators are uniquely suited to allow nonlinear optical image-processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude-transmission characteristic of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. I present experimental results demonstrating the principle and the capability for several different image and noise situations, including deterministic noise and speckle. The bacteriorhodopsin film studied here displays the logarithmic transmission response for write intensities spanning a dynamic range greater than 2 orders of magnitude. RP DOWNIE, JD (reprint author), NASA,AMES RES CTR,MAIL STOP 269-3,MOFFETT FIELD,CA 94035, USA. NR 24 TC 10 Z9 10 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 10 PY 1995 VL 34 IS 23 BP 5210 EP 5217 PG 8 WC Optics SC Optics GA RM677 UT WOS:A1995RM67700022 PM 21052368 ER PT J AU HUA, XM TITARCHUK, L AF HUA, XM TITARCHUK, L TI COMPTONIZATION MODELS AND SPECTROSCOPY OF X-RAY AND GAMMA-RAY SOURCES - A COMBINED STUDY BY MONTE-CARLO AND ANALYTICAL METHODS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, THEORY; PLASMAS; RADIATION MECHANISMS, THERMAL ID THERMAL PLASMAS; ACCRETION DISKS; CYGNUS X-1; SPECTRA; RADIATION; SIGMA; LINE AB We compare the analytical generalized Comptonization models, which take into account the relativistic effects, with Monte Carlo calculations for photon Comptonization by relativistic plasma clouds. We show that the new analytical models extend the previous work to a much wider range of plasma temperatures and optical depths. In general, the emergent spectra from a hot plasma cloud depend upon the spectral and spatial distributions of source photons as well as the plasma temperature and geometry. Based on the comparison between the theoretical and Monte Carlo calculations, we determine quantitatively a range of plasma geometry parameters and temperatures for which the emergent upscattering spectra are insensitive to the spectral and spatial distribution, of source photons. Within this parameter range, we show that the shape of the emergent spectrum depends on two parameters only, namely the plasma temperature and beta, the parameter which characterizes the photon distribution over the number of scatterings which the soft photons undergo before escaping from the plasma cloud. We find the exact solution of the Kompaneets equation for sub-relativistic energies and plasma temperatures in the optically thick regime. The solution covers both the low- and high-energy asymptotic forms studied by Titarchuk. Also, we modify the Sunyaev & Titarchuk formula to obtain a fairly good subrelativistic analytical approximation. This new formula, verified by Monte Carlo calculations, contains as partial cases the analytical results for optically thick and thin cases, respectively. Our Monte Carlo calculations and analytical models allow us to obtain the power-law indices of the photon spectra emergent from hot plasmas as a function of the plasma optical depth at various temperatures. The analytical models, examined by the present Monte Carlo calculations, make possible a more efficient spectral analysis of data obtained from X-ray and gamma-ray sources. RP HUA, XM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY PHYS LAB,GREENBELT,MD 20771, USA. NR 24 TC 104 Z9 104 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP 188 EP 203 DI 10.1086/176045 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM555 UT WOS:A1995RM55500021 ER PT J AU GOEBEL, JH CHEESEMAN, P GERBAULT, F AF GOEBEL, JH CHEESEMAN, P GERBAULT, F TI THE 11-MICRON EMISSIONS OF CARBON STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE CIRCUMSTELLAR MATTER; INFRARED, STARS; MOLECULAR PROCESSES; STARS, CARBON; STARS, FUNDAMENTAL PARAMETERS ID CIRCUMSTELLAR DUST SHELLS; LOW-RESOLUTION SPECTRA; R-CORONAE-BOREALIS; PLANETARY-NEBULAE; SILICON-CARBIDE; OXYGEN-RICH; C-STARS; RADIATIVE-TRANSFER; INFRARED-SPECTRUM; SIC PARTICLES AB A new classification scheme of the IRAS LRS carbon stars is presented. It comprises the separation of 718 probable carbon stars into 12 distinct self-similar spectral groupings. Continuum temperatures are assigned and range from 470 to 5000 K. Three distinct dust species are identifiable: SiC, alpha:C-H, and MgS. In addition to the narrow 11+ mu m emission feature that is commonly attributed to SiC, a broad 11+ mu m emission feature, that is correlated with the 8.5 and 7.7 mu m features, is found and attributed to alpha:C-H. SiC and alpha:C-H band strengths are found to correlate with the temperature progression among the Classes. We find a spectral sequence of Classes that reflects the carbon star evolutionary sequence of spectral types, or alternatively developmental sequences of grain condensation in carbon-rich circumstellar shells. If decreasing temperature corresponds to increasing evolution, then decreasing temperature corresponds to increasing C/O resulting in increasing amounts of carbon rich dust, namely alpha:C-H. If decreasing the temperature corresponds to a grain condensation sequence, then heterogeneous, or induced nucleation scenarios are supported. SiC grains precede alpha:C-H and form the nuclei for the condensation of the latter material. At still lower temperatures, MgS appears to be quite prevalent. No 11.3 mu m PAH features are identified in any of the 718 carbon stars. However, one of the coldest objects, IRAS 15048-5702, and a few others, displays an 11.9 mu m emission feature characteristic of laboratory samples of coronene. That feature corresponds to the C-H out of plane deformation mode of aromatic hydrocarbon. This band indicates the presence of unsaturated, sp(3), hydrocarbon bonds that may subsequently evolve into saturated bonds, sp(2), if, and when, the star enters the planetary nebulae phase of stellar evolution. The effusion of hydrogen from the hydrocarbon grain results in the evolution in wavelength of this 11.9 mu m emission feature to the 11.3 mu m feature. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,STERLING FED SYST,MOFFETT FIELD,CA 94035. RP GOEBEL, JH (reprint author), NASA,AMES RES CTR,SENSORS & INSRUMENTAT BRANCH,MS 244-10,MOFFETT FIELD,CA 94035, USA. NR 94 TC 38 Z9 39 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP 246 EP 257 DI 10.1086/176052 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM555 UT WOS:A1995RM55500028 ER PT J AU ZUCKER, DB RAYMOND, JC SILBER, A MASON, P CURIEL, S VRTILEK, S SCHLEGEL, E AF ZUCKER, DB RAYMOND, JC SILBER, A MASON, P CURIEL, S VRTILEK, S SCHLEGEL, E TI PHASE-RESOLVED IUE AND OPTICAL OBSERVATIONS OF THE POLAR BY CAMELOPARDALIS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; NOVAE; CATACLYSMIC VARIABLES; STARS, INDIVIDUAL (BY CAMELOPARDALIS); ULTRAVIOLET, STARS ID AM-HERCULIS; ULTRAVIOLET OBSERVATIONS; H0538+608 =; RAY; STATE; CYGNI AB Time-resolved IUE observations of the asynchronous polar BY Cam (H0538 + 608) over a period of 11 days show that the N v 1240 Angstrom emission-line velocity varies on the orbital period, with an amplitude of 368 +/- 27 km s(-1). The N v flux also varies on the orbital period, with maximum flux corresponding to maximum blueshift. This behavior is seen in He II 1640 Angstrom as well, although with a smaller velocity amplitude (244 +/- 26 km s(-1)). Variation on the orbital (rather than the white dwarf spin) period implies that the emission must originate outside the magnetosphere of the white dwarf, in the accretion stream, the heated face of the secondary, or some combination of the two. The rise, peak, and fall in line emission take place over similar to 0.3 of an orbit, constraining models of the system geometry; we discuss a number of potential explanations for the observed phenomena, including optically thick (in the lines) emission from the accretion stream, occultation of the emission region by the secondary, and combinations of the two processes. We also propose an alternative scenario, in which X-ray illumination from the environment of the white dwarf gives rise to anisotropic line emission from the accretion stream. Ultraviolet continuum intensities on different nights appeared to be in either low or high flux states; we obtained three nights of optical photometry during the same time period, and the optical light curves corresponding to the high and low flux states were distinct, supporting the idea that the pattern of accretion flow changes. Finally, we note that spectroscopic attempts to observe Na I lambda lambda 8183, 8194 in the photosphere of the secondary were not successful. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. CASE WESTERN RESERVE UNIV,DEPT ASTRON,CLEVELAND,OH 44104. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. RP ZUCKER, DB (reprint author), UNIV WASHINGTON,DEPT ASTRON,FM-20,SEATTLE,WA 98195, USA. NR 36 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP 310 EP 319 DI 10.1086/176056 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM555 UT WOS:A1995RM55500032 ER PT J AU MOHANTY, P SCHLEGEL, EM AF MOHANTY, P SCHLEGEL, EM TI A STUDY OF THE LONG-TERM BEHAVIOR OF THE SU URSAE-MAJORIS DWARF NOVAE VW-HYDRI AND Z-CHAMAELEONTIS SO ASTROPHYSICAL JOURNAL LA English DT Article DE NOVAE,; CATACLYSMIC VARIABLES; STARS, INDIVIDUAL (VW HYDRI, Z CHAMAELEONTIS) ID ORBITAL PERIOD CHANGES; CLOSE BINARIES; SS-CYGNI; SOLAR; SANDPILE; CYCLES; NOISE; STARS AB We present more than 30 years of outburst data on the dwarf novae VW Hyi and Z Cha from visual observations made by southern hemisphere amateurs. We study the statistical properties of the outburst durations, quiescence intervals, and cycle times. We compare correlations between these timescales for VW Hyi and Z Cha with the results for SS Cyg obtained by Cannizzo & Mattei (1992). Z Cha proves to be too faint for a complete analysis. VW Hyi, however, shows a richness of variations comparable to SS Cyg. No apparent differences between VW Hyi and SS Cyg can be attributed solely to the SU UMa phenomenon. C1 UNIV MARYLAND,COLLEGE PK,MD 20742. RP MOHANTY, P (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 668,GREENBELT,MD 20771, USA. NR 30 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP 330 EP 340 DI 10.1086/176058 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM555 UT WOS:A1995RM55500034 ER PT J AU ANGELINI, L WHITE, NE NAGASE, F KALLMAN, TR YOSHIDA, A TAKESHIMA, T BECKER, C PAERELS, F AF ANGELINI, L WHITE, NE NAGASE, F KALLMAN, TR YOSHIDA, A TAKESHIMA, T BECKER, C PAERELS, F TI NEON LINE EMISSION IN THE X-RAY-SPECTRUM OF THE PULSAR 4U-1626-67 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; STARS, INDIVIDUAL (4U 1626-67); X-RAYS, STARS ID HELIUM STARS; EVOLUTION; DISCOVERY; PERIOD AB Using the ASCA Observatory we have discovered a strong emission-line complex centered on 1 keV in the X-ray spectrum of the 7 s pulsar 4U 1626-67, The strongest line is identified with hydrogen-like Ne Ly alpha at 1.008 keV, The strength of the neon emission compared to the expected iron L complex implies a large neon overabundance relative to iron, 4U 1626-67 is a low-mass X-ray binary (LMXRB) system with an orbital period of 2485 s, and is unusual because it is one of a few LMXRB to contain an X-ray pulsar. A hydrogen burning companion star was suggested to explain the X-ray and optical characteristics. Neon is a by-product of helium burning and its overabundance in this system may indicate instead that the companion star is burning (or has burned) helium. C1 INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP ANGELINI, L (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 668,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 28 TC 39 Z9 39 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP L41 EP L45 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM556 UT WOS:A1995RM55600010 ER PT J AU FEIBELMAN, WA AF FEIBELMAN, WA TI THE IUE SPECTRUM OF THE O-VI-SEQUENCE PLANETARY-NEBULA HE-2-55 SO ASTROPHYSICAL JOURNAL LA English DT Article DE PLANETARY NEBULAE, INDIVIDUAL, (HE 2-55); ULTRAVIOLET, STARS ID EXTINCTION; STARS AB The first IUE observations of the ''O VI Sequence'' planetary nebula He 2-55 are reported. The ultraviolet spectrum is dominated by strong emission lines of O V, C IV, He II, and C III], plus a number of weaker ions for which emission line fluxes were measured. N V lambda 1240 and C IV lambda 1549 show P Cygni profiles. The stellar terminal wind velocity of 4500 +/- 400 km s(-1) is derived from the C IV lambda 1549 absorption. Interstellar extinction, E(B - V) = 0.54 +/- 0.1, was determined from the observed flux of the He II lambda 1640/lambda 4686 lines. The only density diagnostic available from low-dispersion data, the Si III]/C III] emission-line ratio, yields an electron density of log N-e = 9.5 +/- 0.5 cm(-3) but usually results in higher log N-e than that derived from the C III] F(lambda 1907/lambda 1909) diagnostic that requires high-dispersion data. RP FEIBELMAN, WA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6841,GREENBELT,MD 20771, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP L87 EP L89 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM556 UT WOS:A1995RM55600020 ER PT J AU HERBIG, T LAWRENCE, CR READHEAD, ACS GULKIS, S AF HERBIG, T LAWRENCE, CR READHEAD, ACS GULKIS, S TI A MEASUREMENT OF THE SUNYAEV-ZELDOVICH EFFECT IN THE COMA CLUSTER OF GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; DISTANCE SCALE; GALAXIES, CLUSTERS, INDIVIDUAL (COMA) ID MICROWAVE BACKGROUND-RADIATION; RADIO OBSERVATIONS; ABELL CLUSTERS; ANISOTROPY; REDSHIFTS; VELOCITY; SCALES; GAS AB We report the detection of the Sunyaev-Zel'dovich effect in the Coma cluster of galaxies with the 5.5 m telescope at the Owens Valley Radio Observatory. The measured decrement of the temperature of the cosmic microwave background is Delta T-0,T-obs,obs -270 +/- 29 mu K After correcting for the effect of discrete radio sources and applying current models for the X-ray atmosphere of the cluster, we calculate the peak of the effect to be Delta T-0(0) = -505 +/- 92 mu K. Using the same X-ray models, and assuming spherical symmetry for the gas atmosphere, we derive a Hubble constant of H-0= 71(-25)(+30) km s(-1) Mpc(-1). This is the first detection of the Sunyaev-Zel'dovich effect in a nearby cluster of galaxies. C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. RP HERBIG, T (reprint author), CALTECH,OWENS VALLEY RADIO OBSERV,PASADENA,CA 91125, USA. NR 24 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP L5 EP L8 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM556 UT WOS:A1995RM55600002 ER PT J AU SELLGREN, K BROOKE, TY SMITH, RG GEBALLE, TR AF SELLGREN, K BROOKE, TY SMITH, RG GEBALLE, TR TI A NEW 3.25 MICRON ABSORPTION FEATURE TOWARD MONOCEROS R2/IRS-3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE DUST; EXTINCTION; INFRARED, GENERAL; ISM, MOLECULES; STARS, PRE-MAIN-SEQUENCE ID INFRARED-SPECTROSCOPY; INTERSTELLAR DUST; EMISSION FEATURES; CLOUDS; MOLECULES; SPECTRA; IDENTIFICATION; EXTINCTION; PROTOSTARS; BANDS AB A new 3.2-3.5 mu m spectrum of the protostar Mon R2/IRS 3 confirms our previous tentative detection of a new absorption feature near 3.25 mu m. The feature in our new spectrum has a central wavelength of 3.256 mu m (3071 cm(-1)) and has a full width at half-maximum of 0.079 mu m (75 cm(-1)). We explore a possible identification with aromatic hydrocarbons at low temperatures, which absorb at a similar wavelength. If the feature is due to aromatics, the derived column density of C-H bonds is similar to 1.8 x 10(18) cm(-2). If the absorbing aromatic molecules are of roughly the same size as those responsible for aromatic emission features in the interstellar medium, then we estimate that similar to 9% of the cosmic abundance of carbon along this line of sight would be in aromatic hydrocarbons, in agreement with abundance estimates from emission features. C1 JET PROPULS LAB,PASADENA,CA 91109. UNIV NEW S WALES,UNIV COLL,DEPT PHYS,AUSTRALIAN DEF FORCE ACAD,CANBERRA,ACT 2600,AUSTRALIA. JOINT ASTRON CTR,HILO,HI 96720. RP SELLGREN, K (reprint author), OHIO STATE UNIV,DEPT ASTRON,174 W 18TH AVE,COLUMBUS,OH 43210, USA. NR 35 TC 61 Z9 61 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP L69 EP L72 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM556 UT WOS:A1995RM55600016 ER PT J AU WOO, R ARMSTRONG, JW BIRD, MK PATZOLD, M AF WOO, R ARMSTRONG, JW BIRD, MK PATZOLD, M TI FINE-SCALE FILAMENTARY STRUCTURE IN CORONAL STREAMERS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERPLANETARY MEDIUM; SOLAR WIND; SUN, CORONA ID RADIO SCATTERING OBSERVATIONS; SOLAR-WIND; DOPPLER SCINTILLATION; DENSITY FLUCTUATIONS; YOHKOH; 1-AU; SUN AB Doppler scintillation measurements of a coronal streamer lasting several solar rotations have been conducted by Ulysses in 1991 over a heliocentric distance range of 14-77 R(0). By showing that the solar corona is filamentary, and that Doppler frequency is the radio counterpart of white-light eclipse pictures processed to enhance spatial gradients, it is demonstrated that Doppler scintillation measurements provide the high spatial resolution that has long eluded white-light coronagraph measurements. The region of enhanced scintillation, spanning an angular extent of 1 degrees.8 in heliographic longitude, coincides with the radially expanding streamer stalk and represents filamentary structure with scale sizes at least as small as 340 km (0 ''.5) when extrapolated to the Sun. Within the stalk of the streamer, the fine-scale structure corresponding to scale sizes in the range of 20-340 km at the Sun and associated with closed magnetic fields amounts to a few percent of the mean density, while outside the stalk, the fine-scale structure associated with open fields is an order of magnitude lower. Clustering of filamentary structure that takes place within the stalk of the streamer is suggestive of multiple current sheets. Comparison with ISEE 3 in situ plasma measurements shows that significant evolution resulting from dynamic interaction with increasing heliocentric distance takes place by the time streamers reach Earth orbit. C1 UNIV BONN,INST RADIOASTRON,D-53121 BONN,GERMANY. UNIV COLOGNE,INST GEOPHYS & METEOROL,D-50923 COLOGNE,GERMANY. RP WOO, R (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 238-725,PASADENA,CA 91109, USA. NR 28 TC 34 Z9 35 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 10 PY 1995 VL 449 IS 1 BP L91 EP L94 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RM556 UT WOS:A1995RM55600021 ER PT J AU NEREM, RS JEKELI, C KAULA, WM AF NEREM, RS JEKELI, C KAULA, WM TI GRAVITY-FIELD DETERMINATION AND CHARACTERISTICS - RETROSPECTIVE AND PROSPECTIVE SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Review ID GRAVITATIONAL MODEL; TEMPORAL VARIATIONS; ABSOLUTE GRAVITY; VENUS GRAVITY; SATELLITE ALTIMETRY; HARMONIC-ANALYSIS; GLOBAL GRAVITY; EARTH ROTATION; GEOSAT DATA; TOPOGRAPHY AB Gravimetry has had a long history, using pendulums, torsion balances, and static spring gravimeters. Relative accuracy adequate for many geophysical problems was already attained by 1900, but it took another half century to build readily portable gravimeters. Calibration and datum definition remained problems until the 1970s when free-fall absolute gravimeters were developed that now have a precision of 10(-3) mGal. The problems of geographic inaccessibility and field party costs (notably in areas of greatest tectonic interest) are now being overcome by airborne gravimetry that has already achieved accuracies of 1-3 mGal with resolutions of 10 to 20 km. Satellite techniques are the best way to determine the long-wavelength variations of the gravity field. The resolution of the models has steadily improved with the number of satellites and the precision of the observations. The best current model includes tracking data from more than 30 satellites, satellite altimetry, and surface gravimetry and has a resolution of about 290 km (harmonic degree 70) with the most recent improvements coming from Doppler orbitography and radiopositioning integrated by satellite (DORIS) tracking of the SPOT 2 satellite and satellite laser ranging (SLR), DORIS, and Global Positioning System (GPS) tracking of the TOPEX/POSEIDON satellite. Meanwhile, radar altimetry has become the dominant technique to infer the marine geoid with a resolution of tens of kilometers or shorter. Similarly, the gravity fields of the Moon, Venus, and Mars have been determined to harmonic degrees 70, 75, and 50, respectively, although tracking limitations result in variations of spatial resolution. Modeling Earth's gravity field from the abundance of precise data has become an increasingly complex task, with which the development of computer capacity has kept pace. Contemporary solutions now entail about 10,000 parameters, half of them for effects other than the fixed gravity field of Earth. Temporal variations arising from tides have long been well modeled, and nontidal changes are now being identified. The improvement in gravitational models engendered corresponding advances in geophysical interpretation. Isostatic models were refined and expanded to account for regional thermal and tectonic histories. Interpretation of the long-wavelength gravity field determined by satellite techniques has been mainly in terms of plate tectonics as a manifestation of mantle convection. Gravity has been significant in inferring that there must be a large increase in viscosity with depth (most strongly, from the apparent slow sinking of subducted slabs). The prospects for increasing accuracy and resolution in the determination of Earth's gravity field rest primarily with the development of new measurement systems. Airborne gravimetry is taking promising new steps using GPS, but significant global model improvement awaits a dedicated satellite gravimetry system, and future satellite altimeter missions will do more for ocean dynamics studies than geoid improvement. Advances in interpretation will occur through the development of other data, such as seismic tomography, and larger-scale computer modeling of tectonics and convection. C1 OHIO STATE UNIV, DEPT GEODET SCI & SURVEYING, COLUMBUS, OH 43210 USA. UNIV CALIF LOS ANGELES, DEPT EARTH & PLANETARY SCI, LOS ANGELES, CA USA. RP NEREM, RS (reprint author), NASA, GODDARD SPACE FLIGHT CTR, SPACE GEODESY BRANCH, GREENBELT, MD 20771 USA. NR 227 TC 22 Z9 24 U1 1 U2 9 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 AUG 10 PY 1995 VL 100 IS B8 BP 15053 EP 15074 DI 10.1029/94JB03257 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RN992 UT WOS:A1995RN99200007 ER PT J AU MCEWAN, MJ ANICICH, VG AF MCEWAN, MJ ANICICH, VG TI A LOW-PRESSURE STUDY OF C2N2 ION CHEMISTRY SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ASSOCIATION REACTIONS; MOLECULE REACTIONS; TITAN; CYANOGEN; SYSTEM; PHOTOCHEMISTRY; ATMOSPHERE; IONOSPHERE; MODEL AB Ion-molecule reactions of C2N2+ and C2N2 With several ions and neutrals observed or predicted to be present in the atmosphere of Titan have been examined in an ion cyclotron resonance spectrometer at room temperature and low pressures. Rate coefficients and branching ratios are reported for N+, N-2(+), HCN+, C2H2+, C2H4+, C3H5+, C4H2+, and C4H3+ With C2N2 and for C2N2+ With N-2 and C2H2. The association reaction between C2N2+ and C2N2 forming C4N4+ was examined in some detail. No evidence was found for radiative (bimolecular) association, but rapid collisional stabilization was observed. The termolecular association rate coefficient is k(3) = 1.7 x 10(-23) cm(6) s(-1)(M = C2N2), and the relative collisional stabilization efficiencies for cm the bath gases M = He, Ne, Ar, and N-2 were also measured. The mean lifetime of the (C4N4+)* complex that exhibited collisional stabilization was tau beta = 104 mu s where beta is the relative efficiency of collisional stabilization. A possible form of the C4N4+ product of association is the ion NCCNNCCN+ resulting from unrearranged addition. A mechanism is also presented showing how pressure saturation can occur when the rate coefficient for association is much less that the collision rate. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 33 TC 6 Z9 6 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD AUG 10 PY 1995 VL 99 IS 32 BP 12204 EP 12208 DI 10.1021/j100032a023 PG 5 WC Chemistry, Physical SC Chemistry GA RN706 UT WOS:A1995RN70600023 ER PT J AU WISCOMBE, WJ AF WISCOMBE, WJ TI ATMOSPHERIC PHYSICS - AN ABSORBING MYSTERY SO NATURE LA English DT Editorial Material RP WISCOMBE, WJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 9 TC 25 Z9 26 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD AUG 10 PY 1995 VL 376 IS 6540 BP 466 EP 467 DI 10.1038/376466a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RN622 UT WOS:A1995RN62200022 ER PT J AU MARTIN, BG FATHAUER, RW JONES, EW KRABACH, TN DEJEWSKI, SM AF MARTIN, BG FATHAUER, RW JONES, EW KRABACH, TN DEJEWSKI, SM TI BLOCKING INJECTED DARK CURRENT IN IMPURITY-BAND-CONDUCTION PHOTODETECTORS USING A PTSI SCHOTTKY-BARRIER SO APPLIED PHYSICS LETTERS LA English DT Article AB An experimental investigation was made on the use of a PtSi Schottky barrier for blocking injected electron dark current in a back-illuminated impurity-band-conduction (IBC) photodetector, a device used for detecting long-wavelength infrared (LWIR) radiation. Measured results on the Schottky barrier height as well as current Versus applied bias results are presented, and show that the desired blocking capability has been attained. At the low operating temperatures (similar to 10 K) of the IBC device, the injected dark current is below our measurement capability for applied biases of up to 10 V. Injected dark current in conventional devices occurs at biases of similar to 1 V. The modified device configuration discussed here would enable one to store the mobile ionized donor charge for subsequent readout. (C) 1995 American Institute of Physics. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP MARTIN, BG (reprint author), ANALYSIS CONSULTANTS,LAKE FOREST,CA 92630, USA. NR 6 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 7 PY 1995 VL 67 IS 6 BP 774 EP 776 DI 10.1063/1.115463 PG 3 WC Physics, Applied SC Physics GA RN017 UT WOS:A1995RN01700015 ER PT J AU KENNEL, CF AF KENNEL, CF TI PROPOSED CUTS TO NASA BUDGET SO SCIENCE LA English DT Letter RP KENNEL, CF (reprint author), NASA,MISSION PLANET EARTH,WASHINGTON,DC 20546, USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD AUG 4 PY 1995 VL 269 IS 5224 BP 621 EP 621 DI 10.1126/science.269.5224.621 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RM702 UT WOS:A1995RM70200006 PM 17758799 ER PT J AU VORPERIAN, V AF VORPERIAN, V TI IMPROVED CIRCUIT ANALYSIS TECHNIQUES REQUIRE MINIMUM ALGEBRA SO EDN LA English DT Article RP VORPERIAN, V (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU CAHNERS-DENVER PUBLISHING CO PI HIGHLANDS RANCH PA 8773 S RIDGELINE BLVD, HIGHLANDS RANCH, CO 80126-2329 SN 0012-7515 J9 EDN JI EDN PD AUG 3 PY 1995 VL 40 IS 16 BP 125 EP & PG 0 WC Engineering, Electrical & Electronic SC Engineering GA RT359 UT WOS:A1995RT35900012 ER PT J AU WARREN, ES HARRIS, JE HASSAN, HA AF WARREN, ES HARRIS, JE HASSAN, HA TI TRANSITION MODEL FOR HIGH-SPEED FLOW SO AIAA JOURNAL LA English DT Article ID BOUNDARY-LAYER-TRANSITION AB A transition model for low speed flows has previously been developed by Young et al. which incorporates first-mode (Tollmien-Schlichting) disturbance information from linear stability theory. The present work extends the model to high-speed flows by incorporating the effects of second-mode disturbances. The transition model is incorporated into a Reynolds-averaged Navier-Stokes solver with a one-equation turbulence model. Results using a variable turbulent Prandtl number approach demonstrate that the current model accurately reproduces available experimental data for first and second-mode dominated transitional flows. The performance of the present model shows significant improvement over previous transition modeling attempts. C1 NASA,LANGLEY RES CTR,FLOW MODELING & CONTROL BRANCH,HAMPTON,VA 23665. RP WARREN, ES (reprint author), N CAROLINA STATE UNIV,DEPT MECH & AEROSP ENGN,RALEIGH,NC 27695, USA. NR 20 TC 7 Z9 11 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD AUG PY 1995 VL 33 IS 8 BP 1391 EP 1397 DI 10.2514/3.12687 PG 7 WC Engineering, Aerospace SC Engineering GA RN902 UT WOS:A1995RN90200004 ER PT J AU JOSLIN, RD NICOLAIDES, RA ERLEBACHER, G HUSSAINI, MY GUNZBURGER, MD AF JOSLIN, RD NICOLAIDES, RA ERLEBACHER, G HUSSAINI, MY GUNZBURGER, MD TI ACTIVE CONTROL OF BOUNDARY-LAYER INSTABILITIES - USE OF SENSORS AND SPECTRAL CONTROLLER SO AIAA JOURNAL LA English DT Note ID SIMULATION C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681. NR 9 TC 19 Z9 19 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD AUG PY 1995 VL 33 IS 8 BP 1521 EP 1523 DI 10.2514/3.12930 PG 3 WC Engineering, Aerospace SC Engineering GA RN902 UT WOS:A1995RN90200025 ER PT J AU FARRUGIA, CJ OSHEROVICH, VA BURLAGA, LF AF FARRUGIA, CJ OSHEROVICH, VA BURLAGA, LF TI THE SELF-SIMILAR, NONLINEAR EVOLUTION OF ROTATING MAGNETIC-FLUX ROPES SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID CORONAL MASS-EJECTIONS; SIMILAR MAGNETOHYDRODYNAMICS AB We study, in the ideal MHD approximation, the non-linear evolution of cylindrical magnetic flux tubes differentially rotating about their symmetry axis. Our force balance consists of inertial terms, which include the centrifugal force, the gradient of the axial magnetic pressure, the magnetic pinch force and the gradient of the gas pressure. We employ the ''separable'' class of self-similar magnetic fields, defined recently. Taking the gas to be a polytrope, we reduce the problem to a single, ordinary differential equation for the evolution function. In general, two regimes of evolution are possible; expansion and oscillation. We investigate the specific effect rotation has on these two modes of evolution. We focus on critical values of the flux rope parameters and show that rotation can suppress the oscillatory mode. We estimate the critical value of the angular velocity Omega(cvit), above which the magnetic flux rope always expands, regardless of the value of the initial energy. Studying small-amplitude oscillations of the rope, we find that torsional oscillations are superimposed on the rotation and that they have a frequency equal to that of the radial oscillations. By setting the axial component of the magnetic field to zero, we study small-amplitude oscillations of a rigidly rotating pinch. We find that the frequency of oscillation omega is inversely proportional to the angular velocity of rotating Omega; the product omega Omega being proportional to the inverse square of the Alfven time. The period of large-amplitude oscillations of a rotating flux rope of low beta increases exponentially with the energy of the equivalent 1D oscillator. With respect to large-amplitude oscillations of a non-rotating flux rope, the only change brought about by rotation is to introduce a multiplicative factor greater than unity, which further increases the period. This multiplicative factor depends on the ratio of the azimuthal speed to the Alfven speed. Finally, considering interplanetary magnetic clouds as cylindrical flux ropes, we inquire whether they rotate. We find that a 1 AU only a minority do. We discuss data on two magnetic clouds where we interpret the presence in each of vortical plasma motion about the symmetry axis as a sign of rotation. Our estimates for the angular velocities suggest that the parameters of the two magnetic clouds are below critical values. The two clouds differ in may respects (such as age, bulk flow speed, size, handedness of the magnetic field, etc.), and we find that their rotational parameters reflect some of these differences, particularly the difference in age. In both clouds, a rough estimate of the radial electric field in the rigidly rotating core, calculated in a non-rotating frame, yields values of the order mV m(-1). C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,LANHAM,MD 20706. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP FARRUGIA, CJ (reprint author), UNIV MALTA,DEPT MATH SCI & TECH EDUC,MSIDA,MALTA. NR 18 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD AUG PY 1995 VL 13 IS 8 BP 815 EP 827 DI 10.1007/s005850050220 PG 13 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA RU166 UT WOS:A1995RU16600002 ER PT J AU GOODMAN, ML AF GOODMAN, ML TI A 3-DIMENSIONAL ITERATIVE MAPPING PROCEDURE FOR THE IMPLEMENTATION OF AN IONOSPHERE MAGNETOSPHERE ANISOTROPIC OHM LAW BOUNDARY-CONDITION IN GLOBAL MAGNETOHYDRODYNAMIC SIMULATIONS SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID AURORAL-ZONE; EARTHS MAGNETOSPHERE; SOLAR-WIND; ELECTRON-PRECIPITATION; LATITUDINAL VARIATION; PLASMA SHEET; ENERGY FLUX; CONDUCTANCES; CONDUCTIVITY; IONIZATION AB The mathematical formulation of an iterative procedure for the numerical implementation of an ionosphere-magnetosphere (IM) anisotropic Ohm's law boundary condition is presented. The procedure may be used in global magnetohydrodynamic (MHD) simulations of the magnetosphere. The basic form of the boundary condition is well known, but a well-defined, simple, explicit method for implementing it in an MHD code has not been presented previously. The boundary condition relates the ionospheric electric field to the magnetic field-aligned current density driven through the ionosphere by the magnetospheric convection electric field, which is orthogonal to the magnetic field B, and maps down into the ionosphere along equipotential magnetic field lines. The source of this electric field is the flow of the solar wind orthogonal to B. The electric field and current density in the ionosphere are connected through an anisotropic conductivity tensor which involves the Hall, Pedersen, and parallel conductivities. Only the height-integrated Hall and Pedersen conductivities (conductances) appear in the final form of the boundary condition, and are assumed to be known functions of position on the spherical surface R = R(1) representing the boundary between the ionosphere and magnetosphere. The implementation presented consists of an iterative mapping of the electrostatic potential psi, the gradient of which gives the electric field, and the field-aligned current density between the IM boundary at R = R(1) and the inner boundary of an MHD code which is taken to be at R(2) > R(1). Given the field-aligned current density on R = R(2), as computed by the MHD simulation, it is mapped down to R = R(1) where it is used to compute psi by solving the equation that is the IM Ohm's law boundary condition. Then psi is mapped out to R = R(2), where it is used to update the electric field and the component of velocity perpendicular to B. The updated electric field and perpendicular velocity serve as new boundary conditions for the MHD simulation which is then used to compute a new field-aligned current density. This process is iterated at each time step. The required Hall and Pedersen conductances may be determined by any method of choice, and may be specified anew at each time step. In this sense the coupling between the ionosphere and magnetosphere may be taken into account in a self-consistent manner. RP GOODMAN, ML (reprint author), NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,CODE 695,GREENBELT,MD 20771, USA. NR 43 TC 29 Z9 29 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD AUG PY 1995 VL 13 IS 8 BP 843 EP 853 DI 10.1007/s00585-995-0843-z PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA RU166 UT WOS:A1995RU16600005 ER PT J AU TSUSAKA, Y SUZUKI, H YAMASHITA, K KUNIEDA, H TAWARA, Y OGASAKA, Y UCHIBORI, Y HONDA, H ITOH, M AWAKI, H TSUNEMI, H HAYASHIDA, K NOMOTO, S WADA, M MIYATA, E SERLEMITSOS, PJ JALOTA, L SOONG, Y AF TSUSAKA, Y SUZUKI, H YAMASHITA, K KUNIEDA, H TAWARA, Y OGASAKA, Y UCHIBORI, Y HONDA, H ITOH, M AWAKI, H TSUNEMI, H HAYASHIDA, K NOMOTO, S WADA, M MIYATA, E SERLEMITSOS, PJ JALOTA, L SOONG, Y TI CHARACTERIZATION OF THE ADVANCED SATELLITE FOR COSMOLOGY AND ASTROPHYSICS X-RAY TELESCOPE - PREFLIGHT CALIBRATION AND RAY-TRACING SO APPLIED OPTICS LA English DT Article AB The x-ray properties of multinested thin-foil mirror x-ray telescopes (XRT's) on board ASCA, the Advanced Satellite for Cosmology and Astrophysics, were fully evaluated with an x-ray pencil beam. Scanning over the telescope aperture of 35 cm in diameter with an x-ray pencil beam, we found the effective area of a set of XRT's to be 325, 200, and 113 cm(2) at energies of 1.5, 4.5, and 8.0 keV, respectively. We derive the point-spread functions (PSF's) of the XRT's by measuring the image profile at the focal plane with an x-ray CCD. The PSF is found to exhibit a sharp core concentrated within 30 arcsec and a broad wing extended to 3 arcmin in half-power diameter. We also evaluate the contribution of stray light, which is caused by the single reflection of x rays by primary or secondary mirrors and by the backside reflection of the mirrors. To obtain the characteristics of the XRT in the energy region of 0.5-10.0 keV, incorporated with the measurements at discrete energies, we develop a ray-tracing method with the telescope design parameter, the PSF, and optical constants. In particular, we obtain the optical constants around the gold-atom M shell (Au-IM) absorption-edge energies by measuring the reflectivity of our mirror sample, with monochromatized x-rays in the energy range of 2.0-3.5 keV from synchrotron radiation. Taking into account the PSF's and optical constants, we find that our ray-tracing program can reproduce all these XRT performances. (C) 1995 Optical Society America. C1 HAMAMATSU PHOTON CO LTD,HAMAMATSU,SHIZUOKA 435,JAPAN. NAGOYA UNIV,DEPT ASTROPHYS,CHIKUSA KU,NAGOYA,AICHI 46401,JAPAN. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. KYOTO UNIV,DEPT PHYS,SAKYO KU,KYOTO 60601,JAPAN. OSAKA UNIV,DEPT EARTH & SPACE SCI,TOYONAKA,OSAKA 560,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP TSUSAKA, Y (reprint author), INST MOLEC SCI,OKAZAKI,AICHI 444,JAPAN. NR 14 TC 39 Z9 39 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD AUG 1 PY 1995 VL 34 IS 22 BP 4848 EP 4856 PG 9 WC Optics SC Optics GA RL484 UT WOS:A1995RL48400031 PM 21052325 ER PT J AU JOHNSTON, KJ FEY, AL ZACHARIAS, N RUSSELL, JL MA, CP DEVEGT, C REYNOLDS, JE JAUNCEY, DL ARCHINAL, BA CARTER, MS CORBIN, TE EUBANKS, TM FLORKOWSKI, DR HALL, DM MCCARTHY, DD MCCULLOCH, PM KING, EA NICOLSON, G SHAFFER, DB AF JOHNSTON, KJ FEY, AL ZACHARIAS, N RUSSELL, JL MA, CP DEVEGT, C REYNOLDS, JE JAUNCEY, DL ARCHINAL, BA CARTER, MS CORBIN, TE EUBANKS, TM FLORKOWSKI, DR HALL, DM MCCARTHY, DD MCCULLOCH, PM KING, EA NICOLSON, G SHAFFER, DB TI A RADIO REFERENCE FRAME SO ASTRONOMICAL JOURNAL LA English DT Article ID OPTICAL REFERENCE FRAME; LONG BASELINE INTERFEROMETRY; MARK-III VLBI; SOURCE POSITIONS; SOUTHERN-HEMISPHERE; LINE INTERFEROMETRY; ADDITIONAL RADIO; NORTHERN-HEMISPHERE; OHIO SURVEY; 5 GHZ AB A catalogue is presented based on the radio positions of 436 extragalactic sources distributed over the entire sky. The positional accuracy of the sources is better than 3 milliarcsec (mas) in both coordinates, with the majority of the sources having errors better than 1 mas. This catalogue is based upon a general solution of all applicable dual frequency 2.3 and 8.3 GHz Mark-m VLBI data available through the end of 1993 consisting of 1,015,292 pairs of group delay and phase delay rate observations. Details and positions are also given for an additional 124 objects that either need further observation or are currently unsuitable for the definition of a reference frame. The final orientation of the catalogue has been obtained by a rotation of the positions into the system of the International Earth Rotation Service and is consistent with the FK5 J2000.0 optical system, within the limits of the link accuracy. (C) 1995 American Astronomical Society. C1 USN OBSERV,WASHINGTON,DC 20392. UNIV SPACE RES ASSOC,WASHINGTON,DC 20024. APPL RES CORP,LANDOVER,MD 20785. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV HAMBURG,HAMBURGER STERNWARTE,HAMBURG,GERMANY. CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. UNIV TASMANIA,HOBART,TAS 7001,AUSTRALIA. RADIOMETR INC,HENDERSON,NV 89014. RP JOHNSTON, KJ (reprint author), USN,RES LAB,DIV REMOTE SENSING,CODE 7200,WASHINGTON,DC 20375, USA. RI Ma, Chopo/D-4751-2012; King, Edward/A-1473-2012; OI King, Edward/0000-0002-6898-2130; Eubanks, Thomas Marshall/0000-0001-9543-0414 NR 81 TC 122 Z9 122 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 1995 VL 110 IS 2 BP 880 EP 915 DI 10.1086/117571 PG 36 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RL500 UT WOS:A1995RL50000037 ER PT J AU LINEWEAVER, CH HANCOCK, S SMOOT, GF LASENBY, AN DAVIES, RD BANDAY, AJ DELACRUZ, CMG WATSON, RA REBOLO, R AF LINEWEAVER, CH HANCOCK, S SMOOT, GF LASENBY, AN DAVIES, RD BANDAY, AJ DELACRUZ, CMG WATSON, RA REBOLO, R TI COMPARISON OF THE COBE DMR AND TENERIFE DATA SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; COSMOLOGY, OBSERVATIONS; DIFFUSE RADIATION; LARGE-SCALE STRUCTURE OF UNIVERSE ID DIFFERENTIAL MICROWAVE RADIOMETER; 1ST-YEAR MAPS; SKY SURVEY AB We have compared the Tenerife data with the COBE Differential Microwave Radiometer (DMR) 2 year data in the declination +40 degrees region of the sky observed by the Tenerife experiment. Using the Galactic plane signal at similar to 30 GHz we show that the two data sets are cross-calibrated to within 5%. The high Galactic latitude data were investigated for the presence of common structures with the properties of cosmic microwave background (CMB) fluctuations. The most prominent feature in the Tenerife data (Delta T similar to 80 mu K) appears to be present in both the 53 and 90 GHz DMR maps and has the Planckian spectrum expected for CMB anisotropy. The cross-correlation function of the Tenerife and DMR scans is indicative of common structure and at zero lag has the value C(0)(1/2) = 34(-15)(+13) mu K. The combination of the spatial and spectral information from the two data sets is consistent with the presence of cosmic microwave background anisotropies common to both. The probability that noise could produce the observed agreement is less than 5%. C1 MULLARD RADIO ASTRON OBSERV,CAVEVDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR SPACE SCI,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. INST ASTROFIS CANARIAS,E-38200 LA LAGUNA,SPAIN. RP LINEWEAVER, CH (reprint author), UNIV STRASBOURG 1,OBSERV ASTRON STRASBOURG,11 RUE UNIV,F-67000 STRASBOURG,FRANCE. NR 15 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1995 VL 448 IS 2 BP 482 EP 487 DI 10.1086/175978 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK722 UT WOS:A1995RK72200002 ER PT J AU PARKER, JW HEAP, SR MALUMUTH, EM AF PARKER, JW HEAP, SR MALUMUTH, EM TI IDENTIFICATION OF EMISSION-LINE STARS IN 30-DORADUS USING HST OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE H II REGIONS; MAGELLANIC CLOUDS; OPEN CLUSTERS AND ASSOCIATIONS, INDIVIDUAL (30 DORADUS); STARS, EVOLUTION; STARS, WOLF-RAYET ID WOLF-RAYET STARS; LARGE MAGELLANIC CLOUD; INITIAL MASS FUNCTION; OB ASSOCIATIONS; ABSOLUTE MAGNITUDES; PLANETARY CAMERA; STANDARD STARS; LOSS RATES; STELLAR; METALLICITY AB Using broadband (F439W) and narrowband (F469N) Hubble Space Telescope archive images of the R136 central cluster of 30 Doradus, we have identified candidate Wolf-Rayet stars from the strength of their He II lambda 4686 emission lines. The number ratio of Wolf-Rayet to O stars found in our data is 0.11 +/- 0.03. Our results are more consistent with an instantaneous burst with an age of about 3 x 10(6) yr than with a continuous star formation scenario. However, even in the starburst scenario, evolutionary model predictions for low-metallicity stellar evolution agree with our observations only if we also assume enhanced mass loss and/or a relatively flat slope (Gamma > -1.35) for the initial mass function with an upper mass limit of more than 80 M(.). C1 NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,ASTRON PROGRAMS,GHRS SCI TEAM,GREENBELT,MD 20771. RP PARKER, JW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,MAIL CODE 681,GREENBELT,MD 20771, USA. NR 60 TC 15 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1995 VL 448 IS 2 BP 705 EP 714 DI 10.1086/175998 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK722 UT WOS:A1995RK72200022 ER PT J AU FEIBELMAN, WA AF FEIBELMAN, WA TI THE IUE SPECTRUM OF THE PLANETARY-NEBULA NGC-6751 SO ASTROPHYSICAL JOURNAL LA English DT Article DE PLANETARY NEBULAE, INDIVIDUAL (NGC 6751); STARS, MASS LOSS; ULTRAVIOLET, ISM ID NGC-6751; NUCLEI; STARS AB We present the first high-dispersion IUE short-wavelength (SWP) spectrum of NGC 6751 (029.2 -05.9) from which log N-c = 3.9 +/- 0.05 cm(-3), terminal wind velocity nu(infinity) = 2450 +/- 150 km s(-1), and a maximum mass-loss rate of M((max)) approximate to 7.9 x 10(-8) M. yr(-1) are determined. Emission-line fluxes from low-dispersion spectra for the epochs 1981 and 1994 are presented which suggest some changes may have occurred. The C III] lambda lambda 1907, 1909 doublet displays an unusual triple-peaked profile in the high-resolution spectrum. The IUE range is characterized by a rich stellar spectrum of carbon lines at various stages of ionization and few nebular lines. RP FEIBELMAN, WA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6841,GREENBELT,MD 20771, USA. NR 28 TC 7 Z9 7 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 1 PY 1995 VL 448 IS 2 BP 766 EP 773 DI 10.1086/176004 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK722 UT WOS:A1995RK72200028 ER PT J AU TSAI, JC HSU, JJL AF TSAI, JC HSU, JJL TI PROTOSTELLAR COLLAPSE WITH A SHOCK SO ASTROPHYSICAL JOURNAL LA English DT Article DE HYDRODYNAMICS; SHOCK WAVES; STARS, FORMATION ID FAR-INFRARED OBSERVATIONS; MOLECULAR CLOUD CORES; STAR FORMATION; HIGH-RESOLUTION; PROTOSTARS AB We reexamine both numerically and analytically the collapse of the singular isothermal sphere in the context of low-mass star formation. We consider the case where the onset of collapse is initiated by some arbitrary process which is accompanied by a central output of either heat or kinetic energy. We find two classes of numerical solutions describing this manner of collapse. The first approaches in time the expansion wave solution of Shu, while the second class is characterized by an ever-decreasing central accretion rate and the presence of an outwardly propagating weak shock. The collapse solution which represents the dividing case between these two classes is determined analytically by a similarity analysis. This solution shares with the expansion wave solution the properties that the gas remains stationary with an r(-2) density profile at large radius and that, at small radius, the gas free-falls onto a nascent core at a constant rate which depends only on the isothermal sound speed. This accretion rate is a factor of similar to 0.1 that predicted by the expansion wave solution: This reduction is due in part to the presence of a weak shock which propagates outward at 1.26 times the sound speed. Gas in the postshock region first moves out subsonically but is then decelerated and begins to collapse. The existence of two classes of numerical collapse solutions is explained in terms of the instability to radial perturbations of the analytic solution. Collapse occurring in the manner described by some of our solutions would eventually unbind a finite-sized core. However, this does not constitute a violation of the instability properties of the singular isothermal sphere which is unstable both to collapse and to expansion. To emphasize this, we consider a purely expanding solution for isothermal spheres. This solution is found to be self-similar and results in a uniform density core in the central regions of the gas. Our solutions may be relevant to the ''luminosity'' problem of protostellar cores since the predicted central accretion rates are significantly reduced relative to that of the expansion wave solution. Furthermore, our calculations indicate that star-forming cloud cores are not very tightly bound and that modest disturbances can easily result in both termination of infall and dispersal of unaccreted material. C1 UNIV CALIF BERKELEY, CTR THEORET ASTROPHYS, BERKELEY, CA 94720 USA. RP TSAI, JC (reprint author), NASA, AMES RES CTR, MAIL STOP 245-3, MOFFETT FIELD, CA 94035 USA. NR 40 TC 32 Z9 32 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 AUG 1 PY 1995 VL 448 IS 2 BP 774 EP 787 DI 10.1086/176005 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK722 UT WOS:A1995RK72200029 ER PT J AU ANDERSON, JD LAU, EL KRISHER, TP DICUS, DA ROSENBAUM, DC TEPLITZ, VL AF ANDERSON, JD LAU, EL KRISHER, TP DICUS, DA ROSENBAUM, DC TEPLITZ, VL TI IMPROVED BOUNDS ON NONLUMINOUS MATTER IN SOLAR ORBIT SO ASTROPHYSICAL JOURNAL LA English DT Article DE CELESTIAL MECHANICS, STELLAR DYNAMICS; DARK MATTER; PLANETS AND SATELLITES, GENERAL; SOLAR SYSTEM, GENERAL ID SHORT-PERIOD COMETS; DARK MATTER; SYSTEM; CLOUD; STAR; SUN AB We improve, using a larger set of observations including Voyager 2 Neptune flyby data, previous bounds on the amount of dark matter (DM) trapped in a spherically symmetric distribution about the Sun. We bound DM by noting that such a distribution would increase the effective mass of the Sun as seen by the outer planets and by finding the uncertainty in that effective mass for Uranus and Neptune in fits to the JPL developmental ephemeris residuals, including optical data and those two planets' Voyager 2 flybys. We extend our previous procedure by fitting more parameters of the developmental ephamerides. In addition, we present here the values for Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 Jupiter-ranging normal points (and incorporate these data as well). Our principal result is to limit DM in spherically symmetric distributions in orbit about the Sun interior to Neptune's orbit to less than Earth mass and interior to Uranus's orbit to about 1/6 of Earth's mass. C1 UNIV TEXAS, CTR PARTICLE PHYS, AUSTIN, TX 78712 USA. UNIV TEXAS, DEPT PHYS, AUSTIN, TX 78712 USA. SO METHODIST UNIV, DEPT PHYS, DALLAS, TX 75275 USA. RP ANDERSON, JD (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 43 TC 45 Z9 45 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 AUG 1 PY 1995 VL 448 IS 2 BP 885 EP 892 DI 10.1086/176017 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK722 UT WOS:A1995RK72200041 ER PT J AU FENIMORE, EE INTZAND, JJM NORRIS, JP BONNELL, JT NEMIROFF, RJ AF FENIMORE, EE INTZAND, JJM NORRIS, JP BONNELL, JT NEMIROFF, RJ TI GAMMA-RAY BURST PEAK DURATION AS A FUNCTION OF ENERGY SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS AB Gamma-ray burst time histories often consist of many peaks. These peaks tend to be narrower at higher energy. If gamma-ray bursts are cosmological, the energy dependence of gamma-ray burst timescales must be understood in order to correct the timescale dependence due to the expansion of the universe. By using the average autocorrelation function and the average pulse width, we show that the narrowing with energy follows, quite well, a power law. The power-law index is similar to-0.4. This is the first quantitative relationship between temporal and spectral structure in gamma-ray bursts. It is unclear what physics causes this relationship. The average autocorrelation has a universal shape such that one energy range scales linearly with time into all other energy ranges. This shape is approximately the sum of two exponentials. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP FENIMORE, EE (reprint author), LOS ALAMOS NATL LAB, MS D436, LOS ALAMOS, NM 87545 USA. OI Nemiroff, Robert/0000-0002-4505-6599 NR 9 TC 190 Z9 195 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 AUG 1 PY 1995 VL 448 IS 2 BP L101 EP L104 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RK720 UT WOS:A1995RK72000010 ER PT J AU NEFF, SG ROBERTS, L HUTCHINGS, JB AF NEFF, SG ROBERTS, L HUTCHINGS, JB TI VLA MAPS OF RADIO GALAXIES TO Z=1 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE GALAXIES, STRUCTURE; RADIO CONTINUUM, GALAXIES; SURVEYS ID QUASARS; EVOLUTION AB We present 6 and 20 cm maps of a sample of 49 radio galaxies with z similar to 0.1-1.0. The sources were chosen without knowledge of morphology and spectral index, to match as nearly as possible the 11 cm flux/redshift distribution of a previously observed sample of quasars (Price et al. 1993). The observations were made with the VLA(4) in its A configuration, to match those of the quasar sample. The properties of these sources have been discussed and compared with the quasars in Hutchings et al. (1994). In this paper we also give the source nux measures and comments on the correspondence with the optically imaged host galaxies. C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. DOMINION ASTROPHYS OBSERV,VICTORIA,BC V8X 4M6,CANADA. RP NEFF, SG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 681,GREENBELT,MD 20771, USA. NR 9 TC 40 Z9 40 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD AUG PY 1995 VL 99 IS 2 BP 349 EP 389 DI 10.1086/192190 PG 41 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RL641 UT WOS:A1995RL64100002 ER PT J AU COX, CV BREGMAN, JN SCHOMBERT, JM AF COX, CV BREGMAN, JN SCHOMBERT, JM TI FAR-INFRARED EMISSION FROM ABELL CLUSTERS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE GALAXIES, CLUSTERS, GENERAL; GALAXIES, ELLIPTIC AND LENTICULAR, CD; INFRARED, GALAXIES; INTERGALACTIC MEDIUM ID COOLING FLOWS; GALAXIES; DUST; GAS AB We have examined the frequency with which central dominant galaxies are sources of far-infrared emission in a complete sample of clusters of galaxies. Previous searches for far-infrared emission (FIR; IRAS 60 and 100 mu m measurements) from dominant cluster galaxies (Bregman, McNamara, & O'Connell 1990; Grabelsky & Ulmer 1990) using small, inhomogeneous samples have found 20%-50% of clusters to have significant FIR emission. In a new study, we analyzed the 60 and 100 mu m emission properties of cD galaxies in a complete sample of 163 Abell Clusters. For comparison, a control sample of 207 blank fields was analyzed to determine the distribution of spurious detections, which is greater than expected from Gaussian statistics. The contribution of Galactic cirrus at 60 and 100 mu m to non-Gaussian noise is clearly demonstrated by the correspondence of a 98% confidence level to a signal to noise of 4 or 4.5 rather than to a signal-to-noise ratio of 2 as expected from Gaussian statistics. After correcting for contaminated fields and spurious detections, we find that similar to 10% of cD galaxies in rich clusters are sources of FIR emission. This rate is lower than that quoted in previous studies, which we attribute to our correction for spurious sources, and to the differences in sample selection and average redshift between our study and previous work. Typical detected cDs have FIR luminosities of similar to 3 x 10(44) ergs s(-1), which is comparable to the blue luminosities from these objects and an order of magnitude greater than the X-ray luminosities produced n the cores of clusters. Dust masses derived from the 60 and 100 mu m fluxes are similar to 10(7) M.. Because only similar to 10% of the clusters have high FIR luminosities, such strong emission is probably a transient state for an individual cluster. C1 NASA HEADQUARTERS,DIV ASTROPHYS CODE SZ,WASHINGTON,DC 20546. CALTECH,JET PROP LAB,IPAC,PASADENA,CA 91125. RP COX, CV (reprint author), UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109, USA. NR 14 TC 21 Z9 21 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD AUG PY 1995 VL 99 IS 2 BP 405 EP 425 DI 10.1086/192192 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RL641 UT WOS:A1995RL64100004 ER PT J AU PANDEY, DK LEE, RB PADEN, J AF PANDEY, DK LEE, RB PADEN, J TI EFFECTS OF ATMOSPHERIC EMISSIVITY ON CLEAR-SKY TEMPERATURES SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT International Conference on Sustainable Development Strategies and Global/Regional/Local Impacts on Atmospheric Composition and Climate CY JAN 25-30, 1993 CL INDIAN INST TECHNOL, DELHI, INDIA SP Indo US Sub Commiss Sci & Technol, Govt India, Dept Sci & Technol, Indian Inst Technol, Delhi HO INDIAN INST TECHNOL DE ATMOSPHERIC EMISSIVITY; CLEAR SKY TEMPERATURE; ERBE; ERRS; OUTGOING LONGWAVE RADIATION; SCANNING RADIOMETERS ID RADIATION BUDGET EXPERIMENT; LONG-WAVE RADIATION; SKIES; FORMULA; TRENDS AB The accurate determination of atmospheric temperatures from outgoing longwave radiation depends upon the effective atmospheric emissivity used in Stefan-Boltzmann's law. We reviewed the literature dealing with the atmospheric emissivity equations for clear sky and studied their effects on the clear sky atmospheric temperatures. The clear sky outgoing longwave radiation data were taken by the National Aeronautics and Space Administration's (NASA) Earth Radiation Budget Satellite (ERBS) scanning radiometers. The five years (1985-1989) of global annual-mean of clear sky atmospheric temperatures with different emissivity values are presented and discussed in this paper. The effect of emissivity on the retrieval of clear sky atmospheric temperatures are found to vary by 7-8 K (Kelvin). C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP PANDEY, DK (reprint author), SCI APPLICAT INT CORP,1 ENTERPRISE PKWY,SUITE 250,HAMPTON,VA 23666, USA. NR 34 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD AUG PY 1995 VL 29 IS 16 BP 2201 EP 2204 DI 10.1016/1352-2310(94)00243-E PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RT641 UT WOS:A1995RT64100026 ER PT J AU VANDOORNIK, DM MILNER, GB WINANS, GA AF VANDOORNIK, DM MILNER, GB WINANS, GA TI AN IMPROVED METHOD OF DATA-COLLECTION FOR TRANSFERRIN POLYMORPHISM IN COHO SALMON (ONCORHYNCHUS-KISUTCH) SO BIOCHEMICAL GENETICS LA English DT Note C1 NOAA,NATL MARINE FISHERIES SERV,NW FISHERIES SCI CTR,SEATTLE,WA 98112. RP VANDOORNIK, DM (reprint author), NATL MARINE FISHERIES SERV,POB 130,MANCHESTER,WA 98353, USA. NR 7 TC 2 Z9 4 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0006-2928 J9 BIOCHEM GENET JI Biochem. Genet. PD AUG PY 1995 VL 33 IS 7-8 BP 257 EP 260 PG 4 WC Biochemistry & Molecular Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Genetics & Heredity GA RY311 UT WOS:A1995RY31100005 PM 8595052 ER PT J AU ZBILUT, JP ZAK, M WEBBER, CL AF ZBILUT, JP ZAK, M WEBBER, CL TI PHYSIOLOGICAL SINGULARITIES IN RESPIRATORY AND CARDIAC DYNAMICS SO CHAOS SOLITONS & FRACTALS LA English DT Article ID HEART-RATE VARIABILITY; TRANSPLANT RECIPIENTS AB Chaotic nonlinear dynamics have been extensively used to analyze the complexities of physiological systems in health and disease. Many assertions in this regard, however, fail on the basis of (a) mathematical assumptions, and (b) basic understanding of the physiology involved. Our preliminary research using experimental data from breathing patterns as well as electrocardiographic signals suggest that some of these dynamics can be understood as oscillators with singular points from which emanate multi-choice responses to excitations. Deviations in the distributions of responses may reflect pathology. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. LOYOLA UNIV,STRITCH SCH MED,DEPT PHYSIOL,MAYWOOD,IL 60153. RP ZBILUT, JP (reprint author), RUSH MED COLL,DEPT MOLEC PHYSIOL & BIOPHYS,1653 W CONGRESS,CHICAGO,IL 60612, USA. NR 44 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD AUG PY 1995 VL 5 IS 8 BP 1509 EP 1516 DI 10.1016/0960-0779(94)00216-D PG 8 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA RV855 UT WOS:A1995RV85500012 ER PT J AU ELISHAKOFF, I LI, YW STARNES, JH AF ELISHAKOFF, I LI, YW STARNES, JH TI BUCKLING MODE LOCALIZATION IN ELASTIC PLATES DUE TO MISPLACEMENT IN THE STIFFENER LOCATION SO CHAOS SOLITONS & FRACTALS LA English DT Article AB This paper deals with the buckling of the stiffened plate under uni-axial compression. The direct integration of the governing differential equation is performed and the exact solution to the problem is obtained. As examples, a square plate with single stiffener, and a stiffened three-span, continuous plate are investigated, with special attention given to the influence of stiffener misplacement on the buckling load and mode shape of the plate. It is found that a small misplacement of the stiffeners from the nominal configuration may change the buckling mode from a global one to a highly localized one. C1 FLORIDA ATLANTIC UNIV, DEPT MECH ENGN, BOCA RATON, FL 33431 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23664 USA. RP FLORIDA ATLANTIC UNIV, CTR APPL STOCHAST RES, BOCA RATON, FL 33431 USA. NR 19 TC 11 Z9 12 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 EI 1873-2887 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD AUG PY 1995 VL 5 IS 8 BP 1517 EP 1531 DI 10.1016/0960-0779(94)00158-M PG 15 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA RV855 UT WOS:A1995RV85500013 ER PT J AU BOKHARI, SH AF BOKHARI, SH TI THE LINUX OPERATING SYSTEM SO COMPUTER LA English DT Article AB The enormous consumer market for IBM PCs and compatibles has made them affordable. Now,with a free operating system called Linux, these inexpensive machines can be converted into powerful workstations for teaching, research, and software development. Linux is a full-fledged operating system that provides all the capabilities normally associated with commercial Unix systems and has excellent compilers for C, C + + , Pascal, Modula-2 and -3, Oberon, Smalltalk, and Fortran. For professionals who use Unix-based workstations at work, Linux permits virtually identical working environments on their personal home machines. For cost-conscious educational institutions-especially in developing nations-Linux can create world-class computing environments from inexpensive, easily maintained PC clones. And, for university students-especially in science and engineering-Linux provides an essentially cost-free path into Unix and X Windows. Until recently, most information about Linux was found only on the Internet. This article attempts to remedy that situation by describing how to obtain, install, and use Linux, as well as the hardware requirements to run it. In addition to providing a survey of pertinent literature, the article describes several Public-domain applications that the author has found useful. C1 NASA,LANGLEY RES CTR,INST COMP APPL SCI & ENGN,HAMPTON,VA 23665. RP BOKHARI, SH (reprint author), UNIV ENGN & TECHNOL,DEPT ELECT ENGN,LAHORE 54890,PAKISTAN. RI Bokhari, Shahid/H-1330-2011 NR 13 TC 7 Z9 8 U1 1 U2 7 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0018-9162 J9 COMPUTER JI Computer PD AUG PY 1995 VL 28 IS 8 BP 74 EP 79 DI 10.1109/2.402081 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA RM692 UT WOS:A1995RM69200010 ER PT J AU KULKARNI, M BELYTSCHKO, T BAYLISS, A AF KULKARNI, M BELYTSCHKO, T BAYLISS, A TI STABILITY AND ERROR ANALYSIS FOR TIME INTEGRATORS APPLIED TO STRAIN-SOFTENING MATERIALS SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID LOCALIZATION AB The behavior of explicit time integrators is examined for the field equations of dynamic viscoplasticity in one dimension. The analysis proceeds by linearizing the field equations about the current state and freezing coefficients so that the solution to the system of ordinary differential equations can be computed explicitly. Amplification matrices for the central difference method (with rate tangent constitutive update) and fourth-order Runge-Kutta schemes are obtained by applying these schemes to the resulting linear, constant coefficient equations. These amplification matrices lead to local truncation error estimates for the temporal integrators as well as to estimates of the resulting growth rate. Analysis of the cental difference method with a forward Euler constitutive update indicates that the local truncation error involves as the product of the third power of the strain-rate and the square of the time step. In viscoplastic models, the viscoplastic strain-rate is an increasing (decreasing) function of the viscoplastic strain in softening (hardening). Also, the eigenvalues of the rate tangent method increase with strain-rate in softening. Thus, it is recommended that the time step be reduced in localization problems to keep the strain-increment within a prescribed tolerance. As a byproduct of the analysis, conditions for numerical stability for the central difference method with a rate tangent constitutive update are obtained for strain-hardening dynamic viscoplasticity. In the softening regime, the resulting linearized differential equations admit exponentially growing solution. Thus, conventional definitions of stability such as Neumann stability and absolute stability are inappropriate. In order to characterize stability of such systems, we introduce the concept of g-rel stability which combines the concept of relative and absolute stability. We show conditions under which the resulting system is g-rel stable and thus characterize the nature of the numerical stability that can be expected in such problems. C1 NORTHWESTERN UNIV,DEPT CIVIL ENGN,EVANSTON,IL 60208. NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23665. NORTHWESTERN UNIV,DEPT ENGN SCI & APPL MATH,EVANSTON,IL 60208. RI Belytschko, Ted/B-6710-2009; Bayliss, Alvin/B-7337-2009 NR 16 TC 11 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Methods Appl. Mech. Eng. PD AUG PY 1995 VL 124 IS 4 BP 335 EP 363 DI 10.1016/0045-7825(95)00786-Z PG 29 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA RR082 UT WOS:A1995RR08200004 ER PT J AU BAUER, FH LIGHTSEY, EG MCCULLOUGH, J ODONNELL, J SCHNURR, R AF BAUER, FH LIGHTSEY, EG MCCULLOUGH, J ODONNELL, J SCHNURR, R TI GADACS - A GPS ATTITUDE DETERMINATION AND CONTROL EXPERIMENT ON A SPARTAN SPACECRAFT SO CONTROL ENGINEERING PRACTICE LA English DT Article; Proceedings Paper CT 13th IFAC Symposium on Automatic Control in Aerospace (AEROSPACE 94) CY 1994 CL PALO ALTO, CA SP Int Federat Automat Control DE ATTITUDE CONTROL; GLOBAL POSITIONING SYSTEM; CONTROL SYSTEM DESIGN; SATELLITE CONTROL; AEROSPACE ENGINEERING AB An attitude experiment is currently being developed to fly on a Spartan Space Shuttle deployed spacecraft. The experiment, called the GPS Attitude Determination And Control System (GADACS), is expected to answer key questions to help pave the way for GPS attitude sensing in the future. An overview of the GADACS experiment, its mission goals, hardware description, and control law design, is presented. RP BAUER, FH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 712,GREENBELT,MD 20771, USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0967-0661 J9 CONTROL ENG PRACT JI Control Eng. Practice PD AUG PY 1995 VL 3 IS 8 BP 1125 EP 1130 DI 10.1016/0967-0661(95)00106-5 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA RM833 UT WOS:A1995RM83300010 ER PT J AU WATMUFF, JH AF WATMUFF, JH TI AN INVESTIGATION OF THE CONSTANT-TEMPERATURE HOT-WIRE ANEMOMETER SO EXPERIMENTAL THERMAL AND FLUID SCIENCE LA English DT Article DE HOT-WIRE; ANEMOMETER; INSTABILITY; FREQUENCY RESPONSE; TRANSFER FUNCTION AB An algorithm is developed for deriving the transfer functions of the constant-temperature hot-wire anemometer of arbitrary complexity. The only restriction is that the bridge elements, including the hot-wire filament, must be modeled by lumped components. A minimum of two equivalent amplifiers are required to model the feedback amplifier properly. The poles of the transfer functions for electronic and velocity perturbations are shown to be identical regardless of the frequency response characteristics of the feedback amplifier and the nature and quantity of components used to model the bridge impedances. Computer simulations are used to explore the behavior of representative configurations. It is shown that the frequency response characteristics of the feedback amplifier must be included in addition to the offset voltage and cable and balance inductance to fully account for the behaviour observed in real systems. This leads to an optimum system response when the balance inductor is in excess of that required for ac bridge balance. Increasing the frequency response and gain of the feedback amplifier have the rather surprising effect of increasing the damping of the dominant poles. It is the higher order poles that are responsible for the instabilities under these conditions. With subminiature wires it is shown that insufficient frequency response of the feedback amplifier is the most likely cause of instabilities. Operating modes are demonstrated that are misleading, in the sense that the operator can be deceived into interpreting an erroneous frequency response. Examples are provided to help operators of the instrument to identify and avoid these rather subtle and undesirable modes of operation. A brief description is given of a new considerations. RP WATMUFF, JH (reprint author), NASA,AMES RES CTR,MCAT INST,MAIL STOP 260-1,MOFFETT FIELD,CA 94035, USA. NR 12 TC 19 Z9 20 U1 0 U2 2 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0894-1777 J9 EXP THERM FLUID SCI JI Exp. Therm. Fluid Sci. PD AUG PY 1995 VL 11 IS 2 BP 117 EP 134 DI 10.1016/0894-1777(94)00137-W PG 18 WC Thermodynamics; Engineering, Mechanical; Physics, Fluids & Plasmas SC Thermodynamics; Engineering; Physics GA RN826 UT WOS:A1995RN82600001 ER PT J AU CHAPMAN, B MEHROTRA, P ZIMA, H AF CHAPMAN, B MEHROTRA, P ZIMA, H TI HIGH-PERFORMANCE FORTRAN LANGUAGES - ADVANCED APPLICATIONS AND THEIR IMPLEMENTATION SO FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF GRID COMPUTING AND ESCIENCE LA English DT Article; Proceedings Paper CT 1994 Europe Conference on High Performance Computing and Networking (HPCN Europe 94) CY 1994 CL MUNICH, GERMANY DE MASSIVELY PARALLEL MACHINES; FORTRAN LANGUAGE; DATA PARALLEL LANGUAGES; DATA DISTRIBUTION; NUMERICAL COMPUTATION ID EXECUTION; LOOPS AB High Performance Fortran Languages such as Vienna Fortran and High Performance Fortran (HPF) allow the programming of massively parallel machines at a relatively high level of abstraction, based on a user-specified distribution of data across the processors of the machine. In this paper we examine the parallelization of two advanced applications - which require irregular data and work distributions - in Vienna Fortran and identify the reasons why the current version of HPF does not provide adequate functionality for formulating efficient parallel versions of these codes. C1 NASA, LANGLEY RES CTR, ICASE, HAMPTON, VA 23681 USA. RP CHAPMAN, B (reprint author), UNIV VIENNA, INST SOFTWARE TECHNOL & PARALLEL SYST, LIECHTENSTEINSTR 22, A-1090 VIENNA, AUSTRIA. NR 16 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD AUG PY 1995 VL 11 IS 4-5 BP 401 EP 407 DI 10.1016/0167-739X(95)00010-P PG 7 WC Computer Science, Theory & Methods SC Computer Science GA RV458 UT WOS:A1995RV45800006 ER PT J AU GIAMPIERI, G VECCHIO, A AF GIAMPIERI, G VECCHIO, A TI LIMITS ON THE GRAVITATIONAL-WAVE BACKGROUND FROM SPACECRAFT DOPPLER EXPERIMENTS SO GENERAL RELATIVITY AND GRAVITATION LA English DT Article ID RADIATION AB Doppler tracking of an interplanetary spacecraft provides an unique opportunity to search for low frequency gravitational waves. In this paper, we describe in detail how Doppler experiments can be used to set an upper limit on a stochastic gravitational background, isotropically distributed. After reviewing the basic equations involved in this technique, we critically analyze three methods of data analysis, based on different assumptions about the physical properties of the signal. C1 UNIV PAVIA,DIPARTIMENTO FIS NUCL & TEOR,I-27100 PAVIA,ITALY. RP GIAMPIERI, G (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Vecchio, Alberto/F-8310-2015 OI Vecchio, Alberto/0000-0002-6254-1617 NR 17 TC 2 Z9 2 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0001-7701 J9 GEN RELAT GRAVIT JI Gen. Relativ. Gravit. PD AUG PY 1995 VL 27 IS 8 BP 793 EP 811 DI 10.1007/BF02113064 PG 19 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RL541 UT WOS:A1995RL54100002 ER PT J AU ARGUS, DF HEFLIN, MB AF ARGUS, DF HEFLIN, MB TI PLATE MOTION AND CRUSTAL DEFORMATION ESTIMATED WITH GEODETIC DATA FROM THE GLOBAL POSITIONING SYSTEM SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GPS AB We use geodetic data taken over four years with the Global Positioning System (GPS) to estimate (1) motion between six major plates and (2) motion relative to these plates of ten sites in plate boundary zones. The degree of consistency between geodetic velocities and rigid plates requires the (one-dimensional) standard errors in horizontal velocities to be similar to 2 mm/yr. Each of the 15 angular velocities describing motion between plate pairs that we estimate with GPS differs insignificantly from the corresponding angular velocity in global plate motion model NUVEL-1A, which averages motion over the past 3 m.y. The motion of the Pacific plate relative to both the Eurasian and North American plates is observed to be faster than predicted by NUVEL-1A, supporting the inference from Very Long Baseline Interferometry (VLBI) that motion of the Pacific plate has sped up over the past few m.y. The Eurasia-North America pole of rotation is estimated to be north of NUVEL-1A, consistent with the independent hypothesis that the pole has recently migrated northward across northeast Asia to near the Lena River delta. Victoria, which lies above the main thrust at the Cascadia subduction zone, moves relative to the interior of the overriding plate at 30% of the velocity of the subducting plate, reinforcing the conclusion that the thrust there is locked beneath the continental shelf and slope. RP ARGUS, DF (reprint author), CALTECH,JET PROP LAB,MAIL STOP 238-600,PASADENA,CA 91109, USA. RI Argus, Donald/F-7704-2011 NR 11 TC 78 Z9 90 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1995 VL 22 IS 15 BP 1973 EP 1976 DI 10.1029/95GL02006 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900010 ER PT J AU CHAO, BF RAY, RD EGBERT, GD AF CHAO, BF RAY, RD EGBERT, GD TI DIURNAL/SEMIDIURNAL OCEANIC TIDAL ANGULAR-MOMENTUM - TOPEX/POSEIDON MODELS IN COMPARISON WITH EARTHS ROTATION RATE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TIDES AB The oceanic tidal angular momentum (OTAM) has been demonstrated to be the primary cause for the diurnal and semidiurnal variations in the Earth's rotational rate, or Delta UT1. Three ocean tide models derived from the Topex/Poseidon altimetry mission are employed to yield predictions of Delta UT1 for eight major dirnal/semidiurnal tides. The predictions are compared with geodetic determinations of Delta UT1 from the very-long-baseline interferometry data both for long-term observations acid during intensive campaigns, The agreement is good, with discrepancies typically within 2-3 mu s. Systematic discrepancies observed for the well-determined M(2) tide clearly reveal the contribution of the Earth's spin libration. C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. OREGON STATE UNIV,COLL OCEAN & ATMOSPHER SCI,CORVALLIS,OR 97331. RP CHAO, BF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. RI Ray, Richard/D-1034-2012; Chao, Benjamin Fong/N-6156-2013; OI Egbert, Gary/0000-0003-1276-8538 NR 21 TC 13 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1995 VL 22 IS 15 BP 1993 EP 1996 DI 10.1029/95GL01788 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900015 ER PT J AU ALEXANDER, MJ PFISTER, L AF ALEXANDER, MJ PFISTER, L TI GRAVITY-WAVE MOMENTUM FLUX IN THE LOWER STRATOSPHERE OVER CONVECTION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ER-2 AIRCRAFT; STEP AB This work describes a method for estimating vertical fluxes of horizontal momentum carried by short horizontal scale gravity waves (lambda(x) = 10-100 km) using aircraft measured winds in the lower stratosphere. We utilize the in situ wind vector and pressure altitude measurements provided by the Meteorological Measurement System (MMS) on board the ER-2 aircraft to compute the momentum flux vectors at the flight level above deep convection during the tropical experiment of the Stratosphere Troposphere Exchange Project (STEP-Tropical), Data from Flight 9 are presented here for illustration. The vertical flux of horizontal momentum in these observations points in opposite directions on either side of the location of a strong convective updraft in the cloud shield. This property of internal gravity waves propagating from a central source compares favorably with previously described model results. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP ALEXANDER, MJ (reprint author), UNIV WASHINGTON,DEPT ATMOSPHER SCI,AK-40,SEATTLE,WA 98195, USA. NR 11 TC 103 Z9 105 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1995 VL 22 IS 15 BP 2029 EP 2032 DI 10.1029/95GL01984 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900024 ER PT J AU RICAUD, PD CARR, ES HARWOOD, RS LAHOZ, WA FROIDEVAUX, L READ, WG WATERS, JW MERGENTHALER, JL KUMER, JB ROCHE, AE PECKHAM, GE AF RICAUD, PD CARR, ES HARWOOD, RS LAHOZ, WA FROIDEVAUX, L READ, WG WATERS, JW MERGENTHALER, JL KUMER, JB ROCHE, AE PECKHAM, GE TI POLAR STRATOSPHERIC CLOUDS AS DEDUCED FROM MLS AND CLAES MEASUREMENTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTIC OZONE EXPERIMENT; AEROSOL; WINTER; WATER; VAPOR AB From 30 August 1992 to 3 September 1992 supersaturated area at 465 K potential temperature (similar to 50 hPa) is deduced from MLS water vapour measurements over western Antarctica, where high extinction coefficients measured by CLAES indicate Polar Stratospheric Clouds (PSCs). These PSCs are attributed partly to the effect of an anticyclone located over South America and partly to localized orographic waves, which raise the isentropes and generate rapid adiabatic cooling. A local minimum in column O-3 (less than or equal to 200 DU) is observed in this area, which is believed to be a consequence of the dynamics. Enhanced ClO abundances downstream of the region indicate PSC processing and chlorine activation. C1 UNIV EDINBURGH,DEPT METEOROL,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. CALTECH,JET PROP LAB,PASADENA,CA 91109. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. HERIOT WATT UNIV,DEPT PHYS,EDINBURGH EH14 4AS,MIDLOTHIAN,SCOTLAND. NR 18 TC 11 Z9 11 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1995 VL 22 IS 15 BP 2033 EP 2036 DI 10.1029/95GL00479 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900025 ER PT J AU NOSE, M IYEMORI, T SUGIURA, M SLAVIN, JA AF NOSE, M IYEMORI, T SUGIURA, M SLAVIN, JA TI A STRONG DAWN DUSK ASYMMETRY IN PC5 PULSATION OCCURRENCE OBSERVED BY THE DE-1 SATELLITE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOCAL TIME ASYMMETRY; MAGNETIC PULSATIONS; MAGNETOSPHERE; ORBIT AB Using the magnetic field data obtained by the DE-1 polar orbiting satellite, statistical characteristics of transverse Pc5 pulsations in the inner magnetosphere are examined. The occurrence distribution is found to have a strong dawn/dusk asymmetry. The occurrence is most frequent in the region around 72 degrees invariant latitude (ILAT) between 0800 and 1000MLT. The distribution shifts to lower ILAT both in the early morning and in the afternoon sectors. Our results are generally consistent with the occurrence distributions obtained by previous studies except for appreciable differences in the local time of the peak occurrence. The dependence of the transverse Pc5 occurrence on solar wind velocity is also investigated. Results show that the higher the solar wind velocity, the more frequent the Pc5 occurrence. This fact suggests that the energy source of these Pc5's is in the Kelvin-Helmholtz instability (KHI) on the magnetopause. To explain the strong dawn/dusk asymmetry, the dependence of the Pc5 occurrence on the angle between the solar wind velocity and the IMP in the ecliptic plane is investigated. It is found that this angle controls the magnetic local time of Pc5 appearance when the solar wind velocity is small. This dependence may be explained by the low threshold of KHI due to an influence of a quasi-parallel bow shock. C1 TOKAI UNIV,INST RES & DEV,TOKYO 151,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP NOSE, M (reprint author), KYOTO UNIV,FAC SCI,KYOTO 60601,JAPAN. RI Slavin, James/H-3170-2012; Nose, Masahito/B-1900-2015 OI Slavin, James/0000-0002-9206-724X; Nose, Masahito/0000-0002-2789-3588 NR 14 TC 29 Z9 29 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1995 VL 22 IS 15 BP 2053 EP 2056 DI 10.1029/95GL01794 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900030 ER PT J AU SLAVIN, JA OWEN, CJ KUZNETSOVA, MM AF SLAVIN, JA OWEN, CJ KUZNETSOVA, MM TI ISEE 3 OBSERVATIONS OF PLASMOIDS WITH FLUX ROPE MAGNECTIC TOPOLOGIES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DEEP GEOMAGNETIC TAIL; ENERGETIC ION BURSTS; DISTANT MAGNETOTAIL; AVERAGE AB This paper reports new evidence for the existence of plasmoids with force-free flux rope magnetic topologies. Motivated by the fact that force-free magnetic flux ropes have intense axial fields at their centers, the ISEE 3 observations have been searched for plasma sheet intervals in which the magnetic field intensity exceeds that in the lobes by greater than or equal to 10% for a minute or longer. A total of 39 "high field regions" were found which met this simple criterion. Further examination showed that they nearly always correspond to the core regions of plasmoids; i.e, intervals of bipolar B(z) with durations of minutes, fast tailward flows and clear substorm associations. A new, more realistic plasmoid magnetic field model which represents the core region as a non-linear force-free flux rope was developed and validated using these events. Finally, observations suggesting that plasmoids evolve toward quasi-force-free flux rope configurations as they move down the tail are presented. RP SLAVIN, JA (reprint author), NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, CODE 696, GREENBELT, MD 20771 USA. RI Owen, Christopher/C-2999-2008; Kuznetsova, Maria/F-6840-2012; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Slavin, James/0000-0002-9206-724X NR 21 TC 47 Z9 48 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 AUG 1 PY 1995 VL 22 IS 15 BP 2061 EP 2064 DI 10.1029/95GL01977 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RM649 UT WOS:A1995RM64900032 ER PT J AU BUBENHEIM, DL SARGIS, R WILSON, D AF BUBENHEIM, DL SARGIS, R WILSON, D TI SPECTRAL CHANGES IN METAL HALIDE AND HIGH-PRESSURE SODIUM LAMPS EQUIPPED WITH ELECTRONIC DIMMING SO HORTSCIENCE LA English DT Article DE CONTROLLED ENVIRONMENTS; GROWTH CHAMBERS; LIGHTING SYSTEMS; PHOTOBIOLOGY; PHOTOSYNTHETIC PHOTON FLUX AB Electronic dimming of high-intensity discharge lamps offers control of photosynthetic photon nux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400-W metal halide (MH) and high-pressure sodium (HPS) lamps were equipped with a dimmer system using silicon-controlled rectifiers (SCR) as highspeed switches. Phase control operation turned the line power off for some period of the alternating current cycle. At full power, the electrical input to BPS and MH lamps was 480 W (root mean squared) and could be decreased to 267 W and 428 W, respectively, before the are was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased, the 589-nm peak remained constant while the 595-nm peak decreased, equaling the 589-nm peak at 345-W input, and the 589-nm peak was almost absent at 270-W input. The MH lamp has a broader spectral output but also has a peak at 589 mn and another smaller peak at 545 nm. As input power to the MH lamps decreased, the peak at 589 diminished to equal the 545-nm peak. As input power approached 428 W, the 589-nm peak shifted ed to 570 nm. While the spectrum changed as input power was decreased in the MH and HPS lamps, the phytochrome equilibrium ratio (P-fr:P-tot) remains unchanged; for both lamp types. RP BUBENHEIM, DL (reprint author), NASA,AMES RES CTR,DIV ADV LIFE SUPPORT,REGENERAT SYST BRANCH,MOFFETT FIELD,CA 94035, USA. NR 4 TC 0 Z9 0 U1 2 U2 4 PU AMER SOC HORTICULTURAL SCIENCE PI ALEXANDRIA PA 701 NORTH SAINT ASAPH STREET, ALEXANDRIA, VA 22314-1998 SN 0018-5345 J9 HORTSCIENCE JI Hortscience PD AUG PY 1995 VL 30 IS 5 BP 1086 EP 1089 PG 4 WC Horticulture SC Agriculture GA RN158 UT WOS:A1995RN15800046 PM 11540960 ER PT J AU LONGARETTI, PY RAPPAPORT, N AF LONGARETTI, PY RAPPAPORT, N TI VISCOUS OVERSTABILITIES IN DENSE NARROW PLANETARY RINGS SO ICARUS LA English DT Article ID URANIAN RINGS; DYNAMICS; URANUS; OCCULTATION; DISKS AB We present a study of viscous overstabilities that can arise in a narrow ring whose particles are tightly packed, so that the pressure tenser exhibits a behavior different than that in a more dilute ring. The main objective of this work is to investigate the role of viscous overstabilities in the excitation of(azimuthal) eccentric modes in narrow rings. The problem is studied through an analytical study of a 2-streamline model and supported by a 10-streamline numerical simulation. There are two possible regimes of instabilities, one in which the mean eccentricity of the ring (i.e., of its azimuthal mode) decreases to a small but finite and nearly constant value, while internal modes of libration reach comparable amplitudes (''small eccentricity regime''), and the other one in which the mean eccentricity of the ring increases to a much larger asymptotic value (''large eccentricity regime'') while internal librations are strongly reduced, but not fully damped. This is to be contrasted with the behavior of viscously stable rings, in which both the librations and the mean eccentricity are fully damped, if one neglects the role of the shepherd satellites. Whether one or the other of these regimes is obtained depends on the initial conditions, but the final state in each regime is controlled by the viscous and self-gravitational evolution and not by these initial conditions. In both regimes, there is no rotating frame in which the ring looks stationary, in opposition to the assumption made in data analyses and in previous theoretical modeling. The large eccentricity regime is generically able to produce rings with stabilized mean eccentricities and mean eccentricity gradients quite similar to those of the eccentric rings of Uranus; however, this regime cannot be reached from an initially circular state, so that if viscous overstabilities alone are to account for the eccentricity of narrow rings, then the ring material must have been in eccentric motion at the time of formation. The residual librations in the large eccentricity regime may explain the problems of the standard self-gravity model for the rigid precession for the epsilon ring, but this appears much more difficult to accomplish for the alpha and beta rings; these residual librations may account for some of the kinematic residuals of the uranian rings, and may also relate to the absence of width-longitude relation in the smaller eccentric rings. (C) 1995 Academic Press, Inc. C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. RP LONGARETTI, PY (reprint author), OBSERV GRENOBLE,BP 53X,F-38041 GRENOBLE,FRANCE. NR 23 TC 15 Z9 15 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 1995 VL 116 IS 2 BP 376 EP 396 DI 10.1006/icar.1995.1131 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP804 UT WOS:A1995RP80400010 ER PT J AU TRYKA, KA BROWN, RH ANICICH, V AF TRYKA, KA BROWN, RH ANICICH, V TI NEAR-INFRARED ABSORPTION-COEFFICIENTS OF SOLID NITROGEN AS A FUNCTION OF TEMPERATURE SO ICARUS LA English DT Article ID TRITON; SURFACE; PLUTO; SPECTRA; RAMAN; ICES; O-2; N-2; CO AB We present the results of laboratory measurements characterizing the near infrared spectrum of solid nitrogen at temperatures between 35 K and 60 K. The measurements show that the appearance of the spectrum in the regions of both the fundamental vibrational transition and its first overtone is temperature dependent. The temperature dependence of the spectrum in the overtone region provides a means of determining the temperature of N-2 ice on Solar System objects using groundbased spectroscopy. (C) 1995 Academic Press, Inc. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP TRYKA, KA (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,MS 170-25,PASADENA,CA 91125, USA. OI Tryka, Kimberly/0000-0002-5399-4235 NR 16 TC 14 Z9 14 U1 2 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 1995 VL 116 IS 2 BP 409 EP 414 DI 10.1006/icar.1995.1133 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP804 UT WOS:A1995RP80400012 ER PT J AU FAHR, A MONKS, PS STIEF, LJ LAUFER, AH AF FAHR, A MONKS, PS STIEF, LJ LAUFER, AH TI EXPERIMENTAL-DETERMINATION OF THE RATE-CONSTANT FOR THE REACTION OF C2H3 WITH H-2 AND IMPLICATIONS FOR THE PARTITIONING OF HYDROCARBONS IN ATMOSPHERES OF THE OUTER PLANETS SO ICARUS LA English DT Article ID INFRARED OBSERVATIONS; VINYL RADICALS; JOVIAN SYSTEM; PHOTOCHEMISTRY; ACETYLENE; NEPTUNE; ABUNDANCES; JUPITER; METHANE; ETHANE AB The reaction between C2H3 and H-2, has been suggested to be potentially important in accounting for observational data on the abundance of low-molecular weight hydrocarbons in the atmospheres of the giant planets, especially the ratio of [C2H6]/[C2H2] in the jovian stratosphere. Previous values of the rate constant for this reaction have depended on or are derived from either calculated estimates or very indirect measurements in complex reaction systems, Further, reported values, both measured and calculated, for the rate constant k (C2H3 + H-2) at T = 298 K have ranged from 2.5 x 10(-17) to 9 x 10(-20) cm(3) molecule(-1) sec(-1). In this work the room temperature rate constant for the reaction of the vinyl radical with molecular hydrogen has been determined by employing laser photolysis coupled to a kinetic-absorption spectroscopic technique and separately via a gas chromatographic product analysis technique. In one set of experiments the vinyl radicals were generated through the lambda = 193 mm photolysis of divinyl mercury using an ArF excimer laser. The time history of vinyl radicals in the presence of hydrogen was monitored using the 1,3-butadiene (vinyl radical combination product) absorption at lambda = 215 nm. By employing kinetic modeling procedures a rate constant of (3 +/- 2) x 10(-20) cm(3) molecule(-1) sec(-1) was derived. Independently, the lambda = 193 mm photolysis of methyl vinyl ketone was used to generate nearly identical concentrations of methyl and vinyl radicals. Gas chromatographic analysis of the reaction products of the methylvinyl mixed radical system in the presence of H-2 result in a rate constant of the order of 1 x 10(-20) cm(3) molecule(-1) sec(-1). The planetary implications of the rate determinations are briefly discussed. (C) 1995 Academic Press, Inc. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. US DOE,OFF BASIC ENERGY SCI,WASHINGTON,DC 20545. RP FAHR, A (reprint author), NIST,DIV CHEM KINET & THERMODYNAM,GAITHERSBURG,MD 20899, USA. RI Monks, Paul/H-6468-2016 OI Monks, Paul/0000-0001-9984-4390 NR 31 TC 25 Z9 25 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 1995 VL 116 IS 2 BP 415 EP 422 DI 10.1006/icar.1995.1134 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP804 UT WOS:A1995RP80400013 ER PT J AU KIM, SJ KIM, YH MAILLARD, JP CALDWELL, J BJORAKER, G AF KIM, SJ KIM, YH MAILLARD, JP CALDWELL, J BJORAKER, G TI 4-MU-M POLAR CONTINUUM OF JUPITER SO ICARUS LA English DT Article ID FUNDAMENTAL-BAND; MU-M; H-3+; EMISSIONS; AURORAE AB Spectra of the 4-mu m continuum of the polar regions of Jupiter were obtained at the Canada-France-Hawaii Telescope. These spectra were compared with a low-resolution spectrum of the equatorial region obtained at the United Kingdom Infrared Telescope. The comparison shows that the continuum level of the equatorial spectrum is at least five times higher than those of the polar spectra. It was also found that the continuum levels of the north polar spectra are two to three times higher than that of a south polar spectrum. Continuum models of polar and equatorial regions were constructed for comparisons with observed spectra, We considered reflection of sunlight by clouds, absorption by polar haze and by molecules, and thermal radiation from the deep atmosphere in the models. We found that the reflection of sunlight is a dominant component of the 4-mu m continuum compared with the thermal emission. Overtone and combination bands of NH3 as well as CH4 and PH3 fundamental bands were identified in absorption in both polar and equatorial regions. We searched for heavy molecules that can possibly condense in the stratosphere of the polar regions forming the polar haze. We found that C6H6 and possibly C4H2 and/or undetected trace heavy hydrocarbons (C atoms greater than 5 or 6) can be the major components possibly creating the polar haze approximately at 20-mbar pressure levels. (C) 1995 Academic Press, Inc. C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. CHUNGNAM NATL UNIV,DEPT ASTRON & SPACE SCI,TAEJON,SOUTH KOREA. INST ASTROPHYS,F-75014 PARIS,FRANCE. YORK UNIV,DEPT PHYS,N YORK,ON M3J 1P3,CANADA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP KIM, SJ (reprint author), KYUNGHEE UNIV,DEPT ASTRON & SPACE SCI,KYUNGGI DO,SOUTH KOREA. RI Bjoraker, Gordon/D-5032-2012; Kim, Sang Joon/E-2383-2013 NR 27 TC 8 Z9 8 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD AUG PY 1995 VL 116 IS 2 BP 423 EP 432 DI 10.1006/icar.1995.1135 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RP804 UT WOS:A1995RP80400014 ER PT J AU SCHUH, MJ WOO, AC AF SCHUH, MJ WOO, AC TI CODE SCALING SO IEEE ANTENNAS AND PROPAGATION MAGAZINE LA English DT Note RP SCHUH, MJ (reprint author), NASA,AMES RES CTR,MAIL STOP 237-2,MOFFETT FIELD,CA 94035, USA. NR 7 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 SN 1045-9243 J9 IEEE ANTENNAS PROPAG JI IEEE Antennas Propag. Mag. PD AUG PY 1995 VL 37 IS 4 BP 82 EP 86 DI 10.1109/74.414743 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA RV488 UT WOS:A1995RV48800011 ER PT J AU OCHIAI, M TEMKIN, H FOROUHAR, S LOGAN, RA AF OCHIAI, M TEMKIN, H FOROUHAR, S LOGAN, RA TI INGAAS-INGAASP BURIED HETEROSTRUCTURE LASERS OPERATING AT 2.0-MU-M SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article ID QUANTUM-WELL LASERS AB Buried heterostructure lasers with highly strained InGaAs-InGaAsP active regions, emitting at 2 mu m have been fabricated and tested, The lasers exhibited threshold current densities of 500 A/cm(2) for 1-mm-long cavities, an internal loss of 11 cm(-1), and characteristic temperatures as high as 50 degrees C, The gain characteristics were also investigated and a linewidth enhancement factor of 8 was determined. C1 JET PROP LAB,PASADENA,CA 91109. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP OCHIAI, M (reprint author), COLORADO STATE UNIV,DEPT ELECT ENGN,FT COLLINS,CO 80523, USA. NR 9 TC 27 Z9 28 U1 2 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD AUG PY 1995 VL 7 IS 8 BP 825 EP 827 DI 10.1109/68.403985 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA RP038 UT WOS:A1995RP03800001 ER PT J AU HARTLEY, TT LORENZO, CF QAMMER, HK AF HARTLEY, TT LORENZO, CF QAMMER, HK TI CHAOS IN A FRACTIONAL ORDER CHUAS SYSTEM SO IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-FUNDAMENTAL THEORY AND APPLICATIONS LA English DT Note ID DISCRETIZED OPERATIONAL CALCULUS; CONVOLUTION QUADRATURE; EQUATIONS; POWER AB This brief studies the effects of fractional dynamics in chaotic systems. In particular, Chua's system is modified to include fractional order elements. By varying the total system order incrementally from 2.6 to 3.7, it is demonstrated that systems of ''order'' less than three can exhibit chaos as well as other nonlinear behavior. This effectively forces a clarification of the definition of order which can no longer be considered only by the total number of differentiations or by the highest power of the Laplace variable. C1 UNIV AKRON,DEPT ELECT ENGN,AKRON,OH 44325. UNIV AKRON,DEPT CHEM ENGN,AKRON,OH 44325. NASA,LEWIS RES CTR,SYST DYNAM BRANCH,CLEVELAND,OH 44135. NR 38 TC 490 Z9 517 U1 3 U2 20 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1057-7122 J9 IEEE T CIRCUITS-I JI IEEE Trans. Circuits Syst. I-Fundam. Theor. Appl. PD AUG PY 1995 VL 42 IS 8 BP 485 EP 490 DI 10.1109/81.404062 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA RP904 UT WOS:A1995RP90400012 ER PT J AU INDERHEES, SE KROEGER, RA JOHNSON, WN KINZER, RL KURFESS, JD GEHRELS, N AF INDERHEES, SE KROEGER, RA JOHNSON, WN KINZER, RL KURFESS, JD GEHRELS, N TI CAPACITIVE CHARGE DIVISION READOUT OF A DOUBLE-SIDED GERMANIUM STRIP DETECTOR SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1994 Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) CY OCT 30-NOV 05, 1994 CL NORFOLK, VA SP IEEE AB We have implemented a capacitive charge-division read-out for a germanium 5x5 orthogonal strip detector. We present measurements of non-linearity, and of energy and position resolution as a function of energy (60 and 662 keV) and of network capacitance. Energy and position non-linearities, which are worse for low capacitance networks, appear in the response along the charge division network, as well as along the length of each detector strip. The non-linearities can be corrected by using an independent gain calibration for each pixel, allowing for use of a lower capacitance charge division network which provides better position resolution. C1 USN,RES LAB,WASHINGTON,DC 20375. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP INDERHEES, SE (reprint author), UNIV SPACE RES ASSOC,WASHINGTON,DC, USA. RI Gehrels, Neil/D-2971-2012; Johnson, Neil/G-3309-2014 NR 5 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1995 VL 42 IS 4 BP 428 EP 431 DI 10.1109/23.467807 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA RP819 UT WOS:A1995RP81900044 ER PT J AU HUBBARD, GS MCMURRAY, RE KELLER, RG WERCINSKI, PF WALTON, JT AF HUBBARD, GS MCMURRAY, RE KELLER, RG WERCINSKI, PF WALTON, JT TI MULTI-LINE GAMMA-RAY SPECTROMETER PERFORMANCE OF A SI(LI) DETECTOR STACK SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 1994 Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) CY OCT 30-NOV 05, 1994 CL NORFOLK, VA SP IEEE AB Experimental data is presented which for the first time displays multi-line spectrometer performance of a Si(Li) detector stack at elevated temperature. The stack consists of four elements, each with a 2 cm diameter active area. Ba-133 and Ag-110m spectra are obtained using various techniques to enhance the peak-to-background ratio. Spectral data are shown as a function of temperature (94 K less than or equal to T less than or equal to 230 K) using optimized peak shaping. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP HUBBARD, GS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Chang, Yong/B-3541-2009 NR 3 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD AUG PY 1995 VL 42 IS 4 BP 441 EP 444 DI 10.1109/23.467804 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA RP819 UT WOS:A1995RP81900047 ER PT J AU JAIN, A RODRIGUEZ, G AF JAIN, A RODRIGUEZ, G TI DIAGONALIZED LAGRANGIAN ROBOT DYNAMICS SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article ID MULTIBODY SYSTEM DYNAMICS; SPATIAL OPERATOR ALGEBRA AB A diagonal equation nu + C(theta nu) = epsilon for robot dynamics is developed by combining recent mass matrix factorization results [1]-[7] with classical Lagrangian mechanics, Diagonalization implies that at each fixed time instant the equation at each joint is decoupled from all of the other joint equations, The equation involves two important variables: a vector nu of total joint rotational rates and a corresponding vector epsilon of working joint moments. The nonlinear Coriolis term C(theta, nu) depends on the joint angles theta and the rates nu. The total joint rates nu are related to the relative joint-angle rates theta by a linear spatial operator m*(theta) mechanized by a base-to-tip spatially recursive algorithm, The total rate nu(k) at a given joint k reflects, in a very unique sense, the total rotational velocity about the joint, and includes the combined effects from all the links between joint k and the manipulator base. This differs from the more traditional Joint-angle rates theta which only reflect the relative, as opposed to total, rotation about the joints, Similarly, the working moments epsilon = lT are related to the applied moments T by the spatial operator l(theta) = m(-1) (theta) mechanized by a tip-to-base spatially recursive algorithm. The working moment epsilon(k) at a given joint k is that part of the applied moment T(k) which does actual mechanical work, while its other part affects only the nonworking internal constraint forces, The diagonal equations are obtained by using the recently developed [1] mass matrix factorization M(theta) = m(theta)m*(theta) in the system Lagrangian. The diagonalization is achieved in velocity space, This means that only the velocity variables theta are replaced with the new variables nu while the original configuration variables a are retained, The new joint velocity variables theta can be viewed as time-derivatives of Lagrangian quasi-coordinates, similar to those of classical mechanics. The velocity transformations are shown to always exist for tree-like, articulated multibody systems, and they can be readily implemented using the spatially recursive filtering and smoothing methods [1], [4], [7] advanced by the authors in recent years. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 18 TC 73 Z9 77 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD AUG PY 1995 VL 11 IS 4 BP 571 EP 584 DI 10.1109/70.406941 PG 14 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA RR511 UT WOS:A1995RR51100009 ER PT J AU JAIN, A RODRIGUEZ, G AF JAIN, A RODRIGUEZ, G TI BASE-INVARIANT SYMMETRICAL DYNAMICS OF FREE-FLYING MANIPULATORS SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article ID SPATIAL OPERATOR ALGEBRA; FORMULATION AB The freedom of choice in designating a base-body for free-flying manipulators gives these manipulators a base-invariance symmetry that is not encountered in fixed-base manipulators. This paper analyzes the relationship between this natural symmetry and the dynamical equations for free-dying manipulators. The base-invariance symmetry is used to develop a new formulation of the manipulator dynamics in which two independent O(N) recursions proceeding in opposite directions are summed together to obtain the complete free-flying manipulator dynamics. Computation of the operational space inertia for the links in the manipulator is also discussed. RP JAIN, A (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 17 TC 5 Z9 6 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD AUG PY 1995 VL 11 IS 4 BP 585 EP 597 DI 10.1109/70.406942 PG 13 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA RR511 UT WOS:A1995RR51100010 ER PT J AU TOWNSHEND, JRG JUSTICE, CO AF TOWNSHEND, JRG JUSTICE, CO TI SPATIAL VARIABILITY OF IMAGES AND THE MONITORING OF CHANGES IN THE NORMALIZED DIFFERENCE VEGETATION INDEX SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SCALES; FIFE AB Pairs of Landsat Multispectral Scanner System images from seven contrasting areas were analysed using scale variance analysis to determine the spatial frequencies present. Specifically images of the Normalized Difference Vegetation Index (NDVI) were analysed, which is sensitive to vegetation activity. Analyses were performed on images for each of the two dates and change images derived by subtracting the NDVI values of the first images from those of the second date. As expected the change images were characterized by higher spatial frequencies than the images of individual dates, but this was only marked for four of the seven areas. Contrary to initial expectations, knowledge of the spatial frequency content of the images from the two dates could not be used to infer the spatial frequencies present in the change images and hence the spatial resolutions needed for detecting change in the NDVI. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP TOWNSHEND, JRG (reprint author), UNIV MARYLAND,DEPT GEOG,GLOBAL REMOTE SENSING SYST LAB,ROOM 1113 LEFRAK HALL,COLLEGE PK,MD 20742, USA. NR 17 TC 38 Z9 39 U1 2 U2 11 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD AUG PY 1995 VL 16 IS 12 BP 2187 EP 2195 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA RR495 UT WOS:A1995RR49500007 ER PT J AU EMSLIE, AG HORACK, JM AF EMSLIE, AG HORACK, JM TI DETERMINATION OF GAMMA-RAY BURST PROPERTIES THROUGH INTEGRAL MOMENT SELF-CONSISTENCY ANALYSIS SO INVERSE PROBLEMS LA English DT Article ID ORIGIN; BATSE AB Cosmic gamma-ray bursts (GRBs) were discovered serendipitously in 1969 by the Vela network of satellites, whose mission was to detect clandestine nuclear explosions. The distribution of GRBs on the sky is isotropic but not radially homogeneous; no known class of objects in the Galaxy satisfies these dual constraints. Furthermore, no counterpart object in the optical, radio or any other waveband has been identified for any of the GRBs observed to date. Since April 1991, over 1000 GRBs have been observed with the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory (GRO), providing unprecedented information on the brightnesses, spectra and celestial coordinates for these bursts. In this article we address the application of inversion techniques to this data set (in particular the brightness distribution of observed bursts) in order to constrain the physical properties of these enigmatic objects. The central method used is based on the interdependence of normalized integral moments of non-negative functions. We apply these techniques to bursts distributed both in Euclidean space and in various cosmological (non-Euclidean) spaces and derive surprisingly powerful constraints on the range of intrinsic luminosities of bursts and/or on their distribution in space. We also demonstrate the formal equivalence of our technique to one involving Mellin transforms. Finally, we point out the generality of our technique, which can be applied straightforwardly to any relation amongst three quantities A, B and C of the form A = B x C, where information about only the distribution of values of A is known or observed, and information about the distribution of values of B or C is desired. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP EMSLIE, AG (reprint author), UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899, USA. RI Horack, John/J-6670-2016 NR 37 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD AUG PY 1995 VL 11 IS 4 BP 743 EP 763 DI 10.1088/0266-5611/11/4/009 PG 21 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA RP926 UT WOS:A1995RP92600009 ER PT J AU GLICKSMAN, ME KOSS, MB WINSA, EA AF GLICKSMAN, ME KOSS, MB WINSA, EA TI THE CHRONOLOGY OF A MICROGRAVITY SPACEFLIGHT EXPERIMENT - IDGE SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID DENDRITIC GROWTH; CONVECTION AB The evolution of the Isothermal Dendritic Growth Experiment (IDGE), which was performed aboard the space shuttle Columbia, provides an example of how a space flight experiment is proposed, developed, built, and operated. To illustrate this example, this article traces the key developments of the IDGE from the initial concept to the actual space flight mission. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP GLICKSMAN, ME (reprint author), RENSSELAER POLYTECH INST,MAT RES CTR,TROY,NY 12180, USA. OI Glicksman, Martin/0000-0002-2675-2759 NR 21 TC 12 Z9 12 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD AUG PY 1995 VL 47 IS 8 BP 49 EP 54 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA RM658 UT WOS:A1995RM65800010 ER PT J AU HARDING, DR OGBUJI, LUT FREEMAN, MJ AF HARDING, DR OGBUJI, LUT FREEMAN, MJ TI TEMPERATURE-DEPENDENCE OF THE BIAXIAL MODULUS, INTRINSIC STRESS AND COMPOSITION OF PLASMA-DEPOSITED SILICON OXYNITRIDE FIRMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; THIN-FILMS; SIN-H AB Silicon oxynitride films were deposited by plasma-enhanced chemical-vapor deposition. The elemental composition was varied between silicon nitride and silicon dioxide: SiO0.3N1.0, SiO0.7N1.6, SiO0.7N1,1, and SiO1.7N0.5. These films were annealed in air, at temperatures of 40-240 degrees C above the deposition temperature (260 degrees C), to determine the stability and behavior of each composition. The biaxial modulus, biaxial intrinsic stress, and elemental composition were measured at discrete intervals within the annealing cycle. Films deposited from primarily ammonia possessed considerable hydrogen (up to 38 at. %) and lost nitrogen and hydrogen at anneal temperatures (260-300 degrees C) only marginally higher than the deposition temperature. As the initial oxygen content increased a different mechanism controlled the behavior of the film: The temperature threshold for change rose to similar or equal to 350 degrees C and the loss of nitrogen was compensated by an equivalent rise in the oxygen content. The transformation from silicon oxynitride to silica was completed after 50 h at 400 degrees C. The initial biaxial modulus of all compositions was 21-30 GPa and the intrinsic stress was -30 to 85 MPa. Increasing the oxygen content raised the temperature threshold where cracking first occurred; the two film compositions with the highest initial oxygen content did not crack, even at the highest temperature (450 degrees C) investigated. At 450 degrees C the biaxial modulus increased to similar or equal to 100 GPa and the intrinsic stress was similar or equal to 200 MPa. These increases could be correlated with the observed change in the him's composition. When nitrogen was replaced by oxygen, the induced stress remained lower than the biaxial strength of the material, but, when nitrogen and hydrogen were lost, stress-relieving microcracking occurred. (C) 1995 American Institute of Physics. C1 RENSSELAER POLYTECH INST,COGSWELL LAB,TROY,NY 12180. RP HARDING, DR (reprint author), NASA,LEWIS RES CTR,NYMA,M-S 106-5,CLEVELAND,OH 44135, USA. NR 25 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 1 PY 1995 VL 78 IS 3 BP 1673 EP 1680 DI 10.1063/1.360263 PG 8 WC Physics, Applied SC Physics GA RK576 UT WOS:A1995RK57600043 ER PT J AU WHITSON, PA CHARLES, JB WILLIAMS, WJ CINTRON, NM AF WHITSON, PA CHARLES, JB WILLIAMS, WJ CINTRON, NM TI CHANGES IN SYMPATHOADRENAL RESPONSE TO STANDING IN HUMANS AFTER SPACEFLIGHT SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE NOREPINEPHRINE; EPINEPHRINE; STROKE VOLUME; ORTHOSTASIS; PERIPHERAL RESISTANCE; MICROGRAVITY ID SPACE AB Plasma catecholamine levels and cardiovascular responses to standing were determined in astronauts before and after several Space Shuttle missions. Blood pressure, heart rate, and cardiac output were measured and blood samples for catecholamine analyses were drawn at the end of the supine and standing periods. Supine plasma norepinephrine and epinephrine concentrations increased 34 and 65%, respectively, on landing day compared with before flight. Standing on landing day resulted in a 65 and 91% increase in plasma norepinephrine and epinephrine, respectively. Supine and standing norepinephrine levels remained elevated 3 days after landing while epinephrine levels returned to preflight levels. On landing day, supine heart rate and systolic blood pressure increased 18 and 8.9%, respectively, and standing heart rate and diastolic blood pressure were elevated by 38 and 19%, respectively. On standing, stroke volume was decreased by 26% on landing day compared with before flight. Collectively, these data indicate that the decreased orthostatic function after spaceflight results largely from the decreased stroke volume. Possible mechanisms contributing to this condition are discussed. RP WHITSON, PA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV MED SCI,MAIL CODE SD,HOUSTON,TX 77058, USA. NR 21 TC 55 Z9 59 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD AUG PY 1995 VL 79 IS 2 BP 428 EP 433 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA RN689 UT WOS:A1995RN68900010 PM 7592198 ER PT J AU KELLEY, MC RIGGIN, D PFAFF, RF SWARTZ, WE PROVIDAKES, JF HUANG, CS AF KELLEY, MC RIGGIN, D PFAFF, RF SWARTZ, WE PROVIDAKES, JF HUANG, CS TI LARGE-AMPLITUDE QUASI-PERIODIC FLUCTUATIONS ASSOCIATED WITH A MIDLATITUDE SPORADIC-E LAYER SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID COLLISIONAL INTERCHANGE INSTABILITY; RADAR INTERFEROMETER OBSERVATIONS; PLASMA-DENSITY MEASUREMENTS; EQUATORIAL ELECTROJET; NUMERICAL SIMULATIONS; SCALE IRREGULARITIES; GRAVITY-WAVE; SPREAD-F; MU-RADAR; FIELD AB For the first time a sounding rocket has been launched into a mid-latitude sporadic E event which was shown to be the source of VHF radar echoes. The layer had a very high peak electron density (similar to 10(6) cm(-3)) and was thicker (similar to 5 km) than most events previously studied by rockets and incoherent scatter radars. The layer was modulated in a remarkable quasi-periodic manner which has not been reported earlier. Twenty cycles of these structures were detected and they seem to be oriented horizontally rather than vertically with periods in the rocket frame in the rage 6-10 s. There is also some evidence that the modulation was detected below as well as above the peak in the electron density, although the bulk of the flight was above the peak. Although the VHF radar echoes were decaying at the time and place where the rocket traversed the E layer, one burst of high amplitude short wavelength fluctuations was detected by the space-borne instruments and had a power spectrum similar to that of a secondary gradient drift mode. This burst occurred at the peak of one of the periodic electron density fluctuations. We discuss two possible sources for the dominant fluctuations: large-scale gradient drift waves and atmospheric acoustic waves. The latter seem most consistent with the data. C1 US DEF NUCL AGCY,RAAE,ALEXANDRIA,VA 22310. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. MITRE CORP,BEDFORD,MA 01730. CHINESE ACAD SCI,WUHAN INST PHYS,WUHAN,PEOPLES R CHINA. RP KELLEY, MC (reprint author), CORNELL UNIV,SCH ELECT ENGN,PHILLIPS HALL,ITHACA,NY 14853, USA. RI Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 39 TC 31 Z9 31 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD AUG PY 1995 VL 57 IS 10 BP 1165 EP 1178 DI 10.1016/0021-9169(94)00130-G PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RL123 UT WOS:A1995RL12300011 ER PT J AU HALLORAN, BP BIKLE, DD HARRIS, J AUTRY, CP CURRIER, PA TANNER, S PATTERSONBUCKENDAHL, P MOREYHOLTON, E AF HALLORAN, BP BIKLE, DD HARRIS, J AUTRY, CP CURRIER, PA TANNER, S PATTERSONBUCKENDAHL, P MOREYHOLTON, E TI SKELETAL UNLOADING INDUCES SELECTIVE RESISTANCE TO THE ANABOLIC ACTIONS OF GROWTH-HORMONE ON BONE SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Article ID OSTEOBLAST-LIKE CELLS; SIMULATED WEIGHTLESSNESS; FACTOR-I; INHIBITION; IMMOBILIZATION; OSTEOCALCIN; CALCIUM; INVITRO; RATS; GH AB Loss of skeletal weight bearing or physical unloading of bone in the growing animal inhibits bone formation and induces a bone mineral deficit, To determine whether the inhibition of bone formation induced by skeletal unloading in the growing animal is a consequence of diminished sensitivity to growth hormone (GH) we studied the effects of skeletal unloading in young hypophysectomized rats treated with GH (0, 50, 500 mu g/100 g body weight/day), Skeletal unloading reduced serum osteocalcin, impaired uptake of H-3-proline into bone, decreased proximal tibial mass, and diminished periosteal bone formation at the tibiofibular junction. When compared with animals receiving excipient alone, GH administration increased bone mass in all animals, The responses in serum osteocalcin, uptake of H-3-proline and Ca-45 into the proximal tibia, and proximal tibial mass in non-weight bearing animals were equal to those in weight bearing animals, The responses in trabecular bone volume in the proximal tibia and bone formation at the tibiofibular junction to GH, however, were reduced significantly by skeletal unloading, Bone unloading prevented completely the increase in metaphyseal trabecular bone normally induced by GH and severely dampened the stimulatory effect (158% vs, 313%, p < 0.002) of GH on periosteal bone formation, These results suggest that while GH can stimulate the overall accumulation of bone mineral in both weight bearing and non-weight bearing animals, skeletal unloading selectively impairs the response of trabecular bone and periosteal bone formation to the anabolic actions of GH. C1 UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA. UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA. VET AFFAIRS MED CTR,DIV ENDOCRINOL,SAN FRANCISCO,CA 94121. NASA,AMES RES CTR,DIV BIOMED RES,MOFFETT FIELD,CA 94035. UNIV CALIF SANTA CRUZ,DEPT BIOL,SANTA CRUZ,CA 95064. NR 28 TC 37 Z9 37 U1 0 U2 0 PU BLACKWELL SCIENCE PUBL INC CAMBRIDGE PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1995 VL 10 IS 8 BP 1168 EP 1176 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA RL318 UT WOS:A1995RL31800004 PM 8585419 ER PT J AU ARNAUD, SB HARPER, JS NAVIDI, M AF ARNAUD, SB HARPER, JS NAVIDI, M TI FEMORAL BONE-MINERAL IN MATURE RATS FED HIGH-SALT DIETS DURING EXPOSURE TO A SPACE-FLIGHT MODEL SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 1 TC 1 Z9 1 U1 0 U2 0 PU BLACKWELL SCIENCE PUBL INC CAMBRIDGE PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1995 VL 10 SU 1 BP S446 EP S446 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA RN484 UT WOS:A1995RN48401227 ER PT J AU GLOBUS, RK MOURSI, A LULL, JC ZIMMERMAN, D DOTY, SB DAMSKY, CH AF GLOBUS, RK MOURSI, A LULL, JC ZIMMERMAN, D DOTY, SB DAMSKY, CH TI FIBRONECTIN REGULATES GENE-EXPRESSION AND PROGRESSIVE DIFFERENTIATION OF OSTEOBLASTS SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT STOMATOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. HOSP SPECIAL SURG,NEW YORK,NY 10021. NR 0 TC 0 Z9 0 U1 1 U2 1 PU BLACKWELL SCIENCE PUBL INC CAMBRIDGE PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1995 VL 10 SU 1 BP S219 EP S219 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA RN484 UT WOS:A1995RN48400322 ER PT J AU VICO, L OHIAMIMASSERON, S LAFAGE, MH MALOUVIER, A LAROCHE, N ALEXANDRE, C DAUNTON, N MOREYHOLTON, E AF VICO, L OHIAMIMASSERON, S LAFAGE, MH MALOUVIER, A LAROCHE, N ALEXANDRE, C DAUNTON, N MOREYHOLTON, E TI DIFFERENTIAL-EFFECTS OF TIME EXPOSURE TO 2G CENTRIFUGATION ON RAT CANCELLOUS BONE SO JOURNAL OF BONE AND MINERAL RESEARCH LA English DT Meeting Abstract C1 FAC MED ST ETIENNE,BIOL TISSU OSSEUX LAB,ST ETIENNE,FRANCE. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE PUBL INC CAMBRIDGE PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0884-0431 J9 J BONE MINER RES JI J. Bone Miner. Res. PD AUG PY 1995 VL 10 SU 1 BP S346 EP S346 PG 1 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA RN484 UT WOS:A1995RN48400828 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI A MODIFICATION OF THE GAUSSIAN-2 APPROACH USING DENSITY-FUNCTIONAL THEORY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRON CORRELATION; ENERGIES AB The quadratic configuration interaction calculation in the Gaussian-2 second-order Moller-Plesset perturbation theory approach, G2(MP2), is replaced by a coupled-cluster (CC) singles and doubles calculation including a perturbational estimate of the triples excitations. In addition, the self-consistent-held (SCF) and MP2 geometry optimizations and SCF frequency calculation in the G2(MP2) approach are replaced by a density functional theory geometry optimization and frequency calculation [using the Becke three parameter hybrid functional with the Lee-Yang-Parr non-local correlation functional (B3LYP)] in the proposed G2(B3LYP/MP2/CC) approach. This simplification does not affect the average absolute deviation from experiment, but decreases the maximum error compared with the G2(MP2) approach. The G2(B3LYP/MP2/CC) atomization energies are compared with those obtained using the B3LYP approach, and the G2(B3LYP/MP2/CC) model is found to be more reliable, even if the B3LYP calculations are performed using a large basis set. RP NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 17 TC 396 Z9 397 U1 2 U2 12 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 AUG 1 PY 1995 VL 103 IS 5 BP 1788 EP 1791 DI 10.1063/1.469752 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RL767 UT WOS:A1995RL76700007 ER PT J AU BALACHANDRAN, NK RIND, D AF BALACHANDRAN, NK RIND, D TI MODELING THE EFFECTS OF UV VARIABILITY AND THE QBO ON THE TROPOSPHERE-STRATOSPHERE SYSTEM .1. THE MIDDLE ATMOSPHERE SO JOURNAL OF CLIMATE LA English DT Article ID QUASI-BIENNIAL OSCILLATION; NORTHERN-HEMISPHERE WINTER; INTERANNUAL VARIABILITY; SOLAR-CYCLE; CIRCULATION; CLIMATE; MODULATION; WARMINGS; MB AB Results of experiments with a GCM involving changes in UV input (+/-25%, +/-10%, +/-5% at wavelengths below 0.3 mu m) and simulated equatorial QBO are presented, with emphasis on the middle atmosphere response. The UV forcing employed is larger than observed during the last solar cycle and does not vary with wavelength, hence the relationship of these results to those from actual solar UV forcing should be treated with caution. The QBO alters the location of the zero wind line and the horizontal shear of the zonal wind in the low to middle stratosphere, while the UV change alters die magnitude of the polar jet and the vertical shear of the zonal wind. Both mechanisms thus affect planetary wave propagation. The east phase of the QBO leads to tropical cooling and high-latitude warming in the lower stratosphere; with opposite effects in the upper stratosphere. This quadrupole pattern is also seen in the observations. The high-latitude responses are due to altered planetary wave effects, while the model's tropical response in the upper stratosphere is due to gravity wave drag. Increased UV forcing warms tropical latitudes in the middle atmosphere, resulting in stronger extratropical west winds, an effect which peaks in the upper stratosphere/lower mesosphere with the more extreme UV forcing but at lower altitudes and smaller wind variations with the more realistic forcing. The increased vertical gradient of the zonal wind leads to increased vertical propagation of planetary waves, altering energy convergences and temperatures. The exact altitudes affected depend upon the UV forcing applied. Results with combined QBO and UV forcing show that in the Northern Hemisphere, polar warming for the east QBO is stronger when the UV input is reduced by 25% and 5% as increased wave propagation to high latitudes (east QBO effect) is prevented from then propagating vertically(reduced UV effect). The model results are thus in general agreement with observations associated with solar UV/QBO variations, although the west phase is not absolutely warmer with increased UV. Questions remain concerning the actual variation of stratospheric winds with the solar cycle as the magnitude of the variations reported in some observations cannot be associated with UV variations in this model (but do arise in the model without any external forcing). The model results actually come closer to reproducing observations with the reduced magnitude of UV forcing due to the lower altitude of west wind response, despite the smaller wind variations involved. An evaluation of the reality of the reported effects of combined QBO and solar UV variations on the middle atmosphere requires the use of proper UV solar cycle forcing and should include possible ozone variations. C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. COLUMBIA UNIV,INST GLOBAL SYST,NEW YORK,NY. NR 30 TC 84 Z9 86 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD AUG PY 1995 VL 8 IS 8 BP 2058 EP 2079 DI 10.1175/1520-0442(1995)008<2058:MTEOUV>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RN694 UT WOS:A1995RN69400010 ER PT J AU ROLIN, TD SZOFRAN, FR AF ROLIN, TD SZOFRAN, FR TI DETERMINATION OF THE ELECTRICAL-CONDUCTIVITY OF LIQUID GE0.95SI0.05 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID VERTICAL MAGNETIC-FIELD; CRYSTAL-GROWTH AB We have measured the electrical conductivity of molten germanium-silicon Ge0.95Si0.05 from the liquidus temperature (1050 degrees C) up to 1220 degrees C. The data were acquired with a unique apparatus which utilizes the standard four-probe technique. The basic unit consists of a fused silica enclosure that contains hermetic glass-to-tungsten seals that can support vacuum pressures down to 10(-7) Torr. With calibration, the measurement error for the low vapor pressure materials of this study was typically less than 7%. The temperature dependence of the electrical conductivity of a Ge0.95Si0.05 melt was found to vary from similar to 22 300 ohm(-1) cm(-1) at the liquidus temperature down to similar to 16 000 ohm(-1) cm(-1) at 1220 degrees C. The negative temperature coefficient as well as the magnitude of these data clearly indicate that the molten material is metallic in nature despite the semiconducting properties of the solid. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NR 20 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD AUG PY 1995 VL 153 IS 1-2 BP 6 EP 10 DI 10.1016/S0022-0248(08)80141-8 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA RQ414 UT WOS:A1995RQ41400002 ER PT J AU ELLENDER, RD HUANG, LP SHARP, SL TETTLETON, RP AF ELLENDER, RD HUANG, LP SHARP, SL TETTLETON, RP TI ISOLATION, ENUMERATION, AND IDENTIFICATION OF GRAM-POSITIVE COCCI FROM FROZEN CRABMEAT SO JOURNAL OF FOOD PROTECTION LA English DT Article DE STAPHYLOCOCCI; CRABMEAT; DETECTION ID BACTERIOLOGICAL QUALITY; STAPHYLOCOCCUS-AUREUS; SEAFOOD PRODUCTS; WATERS; FRESH AB Bacterial levels in frozen crabmeat samples were determined by plate counts using four staphylococcal isolation media incubated for 24, 48, and 72 h at 26 and 35 degrees C. Staphylococcal counts determined by the spread-plate Food and Drug Administration Baird-Parker protocol incubated at 35 degrees C for 48 h (FDABP48-35) served as the standard for comparison. When FDABP48-35 counts were compared to counts from 29 combinations of media, time of incubation, and incubation temperature, only FDABP and Borrego, Florido, Mrocek, and Romero (BFMR) counts, representing 11 combinations, were statistically comparable to FDABP48-35 counts. Cocci (91.5%) were the dominant bacterial type; gram-positive rods (8.3%) and gramnegative isolates (0.2%) were also detected. Isolates tested by the coagulase reaction were predominantly coagulase negative (CN) (97.7%). Of 100 isolates analyzed by the BIOLOG identification procedure, 62% were classified as Staphylococcus lentus, S. hominis, and S. epidermidis. Three isolates were identified as Staphylococcus aureus. These data indicate that species identification of staphylococci from crabmeat can assist in determining the source of contamination, and that staphylococcal isolates from crabmeat are more likely to be coagulase negative. C1 NATL MARINE FISHERIES SERV,NATL SEAFOOD INSPECT LAB,PASCAGOULA,MS 39568. RP ELLENDER, RD (reprint author), UNIV SO MISSISSIPPI,DEPT BIOL SCI,BOX 5165,HATTIESBURG,MS 39406, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU INT ASSOC MILK FOOD ENVIRONMENTAL SANITARIANS, INC PI DES MOINES PA 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2838 SN 0362-028X J9 J FOOD PROTECT JI J. Food Prot. PD AUG PY 1995 VL 58 IS 8 BP 853 EP 857 PG 5 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA RQ829 UT WOS:A1995RQ82900005 ER PT J AU LUHMANN, JG KASPRZAK, WT GREBOWSKY, JM AF LUHMANN, JG KASPRZAK, WT GREBOWSKY, JM TI ON REMOVING MOLECULAR-IONS FROM VENUS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ENERGETIC IONS; TAIL; MAGNETOTAIL; PICKUP AB Acceleration or ''pickup'' of exospheric atomic oxygen ions by the interplanetary convection electric field is a generally accepted mechanism for the observed removal of O+ from Venus. However, heavier escaping molecular ions (e.g., O-2(+), CO2+, N-2(+), CO+, and NO+) in high abundances were also detected in the wake by the Pioneer Venus Orbiter (PVO) neutral mass spectrometer (ONMS) operating in its ion mode. It was recently demonstrated that pickup of O+ at low velocities from the terminator upper ionosphere could explain some characteristics of the Venus ionospheric ''tail rays.'' Since the PVO ion mass spectrometer data indicate that a significant molecular ion component also contributes to the terminator ionosphere above the collisional region (greater than or equal to 250 to 300 km altitude), we apply the tail ray model to study both the associated low-altitude O+ flows and the behavior of heavier ions of similar origin. The predicted flow vectors show dawn/dusk asymmetries similar to those in the ONMS observations. Further, the heavier ions achieve higher peak energies, thus improving their chances of detection by the ONMS which has an energy threshold of similar to 36 eV in the spacecraft frame. The appeal of this explanation is that no exotic or complicated interpretations are required, and that a broad set of diverse observations fit a common scenario. The same mechanism could in principle be operating at Mars where molecular ions were also detected in the wake on Phobos 2. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RI Grebowsky, Joseph/I-7185-2013 NR 15 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14515 EP 14521 DI 10.1029/95JA00538 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400005 ER PT J AU POLLOCK, CJ CHANDLER, MO MOORE, TE ARNOLDY, RL KINTNER, PM CHESNEY, S CAHILL, LJ AF POLLOCK, CJ CHANDLER, MO MOORE, TE ARNOLDY, RL KINTNER, PM CHESNEY, S CAHILL, LJ TI PREFERENTIAL HEATING OF LIGHT-IONS DURING AN IONOSPHERIC AR+ INJECTION EXPERIMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID BEAM INSTABILITIES; ENVIRONMENT; WAVES AB The Argon Release for Controlled Studies (ARCS) 4 sounding rocket was launched northward into high altitude from Poker Flat Research Range on February 23, 1990. The vehicle crossed geomagnetic field lines containing discrete auroral activity, An instrumented subpayload released 100 eV and 200 eV Ar+ ion beams sequentially, in a direction largely perpendicular to both the local geomagnetic field and the subpayload spin axis. The instrumented main payload was separated along field lines from the beam-emitting subpayload by a distance which increased at a steady rate of similar to 2.4 m s(-1). Three-dimensional mass spectrometric ion observations of ambient H+ and O+ ions, obtained on board the main payload, are presented. Main payload electric field observations in the frequency range 0-16 kHz, are also presented. These observations are presented to demonstrate the operation of transverse ion acceleration, which was differential with respect to ion mass, primarily during 100-eV beam operations. The preferential transverse acceleration of ambient H+ ions, as compared with ambient Of ions, during the second, third, fourth, and fifth 100-eV beam operations, is attributed to a resonance among the injected Ar+ ions, beam-generated lower hybrid waves, and H+ ions in the tail of the ambient thermal distribution. This work provides experimental support of processes predicted by previously published theory and simulations. C1 UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,DURHAM,NH 03824. UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. CORNELL UNIV,DEPT ELECT ENGN,ITHACA,NY 14850. RP POLLOCK, CJ (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,SPACE PLASMA PHYS BRANCH,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 19 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14557 EP 14568 DI 10.1029/94JA03238 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400008 ER PT J AU BUONSANTO, MJ RICHARDS, PG TOBISKA, WK SOLOMON, SC TUNG, YK FENNELLY, JA AF BUONSANTO, MJ RICHARDS, PG TOBISKA, WK SOLOMON, SC TUNG, YK FENNELLY, JA TI IONOSPHERIC ELECTRON-DENSITIES CALCULATED USING DIFFERENT EUV FLUX MODELS AND CROSS-SECTIONS - COMPARISON WITH RADAR DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID REACTION-RATE COEFFICIENTS; E-F1 REGION IONOSPHERE; SOLAR EUV; F-REGION; ATOMIC OXYGEN; IONIZATION FREQUENCIES; N2; PHOTOIONIZATION; PHOTOELECTRON; O2 AB The recent availability of the new EUVAC (Richards et al., 1994) and EUV94X (Tobiska, 1993b, 1994) solar flux models and new wavelength bin averaged photoionization and photoabsorption cross section sets led us to investigate how these new flux models and cross sections compare with each other and how well electron densities (N-e) calculated using them compare with actual measurements collected by the incoherent scatter radar at Millstone Hill (42.6 degrees N, 288.5 degrees E). In this study we use the Millstone Hill semiempirical ionospheric model, which has been developed from the photochemical model of Buonsanto et al. (1992). For the F2 region, this model uses determinations of the motion term in the N-e continuity equation obtained from nine-position radar data. We also include two simulations from the field line interhemispheric plasma (FLIP) model. All the model results underestimate the measured N-e in the E region, except that the EUV94X model produces reasonable agreement with the data at the E region peak because of a large Lyman beta (1026 Angstrom) flux, but gives an unrealistically deep E-F1 valley. The ionospheric models predict that the O-2(+) density is larger than the NO+ density in the E region, while numerous rocket measurements show a larger NO+ density. Thus the discrepancy between the ionospheric models and the radar data in the E region is most likely due to an incomplete understanding of the NO+ chemistry. In the F2 region, the photoionization rate given by EW94X is significantly larger than that given by the EUVAC and earlier models. This is due to larger EUV fluxes in EW94X compared to EUVAC over the entire 300-1050 Angstrom wavelength range, apart from some individual spectral lines, In the case of EUVAC, this is partly compensated for by larger photoelectron impact ionization due to the larger EUV fluxes below 250 Angstrom. The differences between ionospheric model results for the different cross-section sets are generally much smaller than the differences with the data. C1 UNIV ALABAMA,EARTH SYST SCI LAB,HUNTSVILLE,AL 35899. UNIV ALABAMA,DEPT COMP SCI,HUNTSVILLE,AL 35899. UNIV ALABAMA,CTR SPACE PLASMA & AERONOM RES,HUNTSVILLE,AL 35899. UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,BOULDER,CO 80309. TELOS JET PROP LAB,PASADENA,CA 91109. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP BUONSANTO, MJ (reprint author), MIT,HAYSTACK OBSERV,ATMOSPHER SCI GRP,WESTFORD,MA 01886, USA. RI Solomon, Stanley/J-4847-2012 OI Solomon, Stanley/0000-0002-5291-3034 NR 59 TC 29 Z9 29 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14569 EP 14580 DI 10.1029/95JA00680 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400009 ER PT J AU TAGUCHI, S SUGIURA, M IYEMORI, T WINNINGHAM, JD SLAVIN, JA AF TAGUCHI, S SUGIURA, M IYEMORI, T WINNINGHAM, JD SLAVIN, JA TI HIGHLY STRUCTURED IONOSPHERIC CONVECTION FOR NORTHWARD INTERPLANETARY MAGNETIC-FIELD - A CASE-STUDY WITH DE-2 OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID LATITUDE BOUNDARY-LAYER; POLAR-CAP; BIRKELAND CURRENTS; MAGNETOTAIL; ARCS; MAGNETOPAUSE; ALTITUDES; PERIODS; MODEL; FLOW AB Dynamics Explorer 2 observed a highly structured plasma convection in the dawn sector of the high-latitude ionosphere on October 25, 1981. Analyzing the magnetic and electric field and plasma data for the event, we have clarified the relation between the electric field variations and the plasmas. There is a region of spiky electric field variations that create a highly structured convection. This region of spiky electric field variations generally coincides with a region having source electrons of low temperature (roughly 60-100 eV) and high density (roughly 1-5 cm(-3), sometimes much higher). Ions having energies of several hundred to several kilo electron volts precipitate in the region of the spiky electric field variations. Results of the analysis also suggest that the highly structured plasma drift is detached from the dayside reverse convection, that is, sunward flow at the highest latitudes and antisunward flow at lower latitudes. Thus our results do not agree with some of the previous studies which suggested that the structured plasma convection is a continuation of the dayside convection that has become irregular near the nightside edge and that its source region is the plasma sheet. We suggest that the source for the highly structured convection lies in the distant low-latitude boundary layer, and propose a source electric field configuration. C1 UNIV ELECTROCOMMUN,DEPT ELECTR ENGN,TOKYO,JAPAN. KYOTO UNIV,FAC SCI,DATA ANALYSIS CTR GEOMAGNETISM & SPACEMAGNETISM,KYOTO 606,JAPAN. TOKAI UNIV,INST RES & DEV,TOKYO 151,JAPAN. SW RES INST,SAN ANTONIO,TX 78284. RP TAGUCHI, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 696,GREENBELT,MD 20771, USA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 21 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14743 EP 14753 DI 10.1029/94JA03373 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400022 ER PT J AU BURLAGA, LF NESS, NF MCDONALD, FB AF BURLAGA, LF NESS, NF MCDONALD, FB TI MAGNETIC-FIELDS AND COSMIC-RAYS IN THE DISTANT HELIOSPHERE AT SOLAR MAXIMUM - VOYAGER-2 OBSERVATIONS NEAR 32-AU DURING 1990 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID OUTER HELIOSPHERE; MODULATION; FLUCTUATIONS AB The intensity of >70 MeV cosmic ray protons observed during solar cycle 22 by Voyager 2 (V2) in the distant heliosphere reached a minimum in 1990, corresponding to the maximum of solar activity in mid-1989 (allowing for the propagation time of the solar wind from the sun to Voyager 2 near 32 AU). A step decrease in the cosmic ray intensity observed within the first approximate to 125 days of 1990 was caused by a global merged interaction region (GMIR), consisting of a cluster of large-amplitude magnetic field strength fluctuations, in which the field was predominantly stronger than average. The step decrease consists of four events in each of which the decrease in cosmic ray intensity is relatively large, and the recovery is either brief or absent. The relation between the cosmic ray intensity and the magnetic field strength observed near 32 AU during this period at the maximum of solar activity in 1989/1990 is similar to that which Voyager 2 observed near 11 AU in 1982/1983 following the maximum of solar activity in the previous solar cycle in 1980. The local changes in the cosmic ray intensity profile are related to the magnetic field strength. Near solar maximum the emission rate of ejecta, which contain magnetic fields that deviate significantly from the spiral direction, is a maximum. Nevertheless, the distribution of elevation angles of the magnetic field observed by Voyager 2 during 1990 is essentially the same as that observed during earlier parts of the solar cycle from 1986 through 1989, including solar minimum in 1986 and 1987. During 1990, the width of the distribution of elevation angles at approximate to 32 AU was the same as that observed at 1 AU. Sectors were observed, but no sector structure was present during 1990, just as in 1988, 1989, and 1991. The distribution of daily averages of the magnetic field strength is lognormal for 0.05 nT < B < 0.25 nT. However there are more strong magnetic fields than the lognormal distribution predicts for 0.25 nT < B < 0.4 nT, owing to the large MIRs. The large-scale fluctuations of the magnetic field strength have a multifractal structure in the low-frequency range from 2.7 days to at least 21.3 days that influences the cosmic ray intensity profile. C1 UNIV MARYLAND, INST PHYS SCI & TECHNOL, COLLEGE PK, MD 20742 USA. UNIV DELAWARE, BARTOL RES INST, NEWARK, DE 19716 USA. RP BURLAGA, LF (reprint author), NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, GREENBELT, MD 20771 USA. NR 41 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14763 EP 14771 DI 10.1029/95JA01557 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400024 ER PT J AU JURAC, S BARAGIOLA, RA JOHNSON, RE SITTLER, EC AF JURAC, S BARAGIOLA, RA JOHNSON, RE SITTLER, EC TI CHARGING OF ICE GRAINS BY LOW-ENERGY PLASMAS - APPLICATION TO SATURN E-RING SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SECONDARY-ELECTRON-EMISSION; CROSS-SECTIONS; SPACE PLASMAS; EV SCATTERING; DUST GRAINS; SOLID H2O; MAGNETOSPHERE; ORIGIN AB The charging of ice grains in planetary plasmas is studied, including the effects of secondary electron emission and backscattering of the incident electrons. It is shown that existing charging models can not be simply extrapolated to the low-energy electron regime (below 30 eV) common in planetary magnetospheric plasmas. We derive expressions for the electrical potential of a grain immersed in a low-energy plasma which more carefully account for electron reflection and the threshold for secondary electron emission. Using plasma parameters from Voyager PLS experiment, we calculate the potential of Saturn's E ring grains to vary from -5.5 V at 4 R(s) to 5 V at 10 R(s). C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP JURAC, S (reprint author), UNIV VIRGINIA,SPACE RES LAB,THORNTON HALL B103,CHARLOTTESVILLE,VA 22903, USA. NR 46 TC 48 Z9 48 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14821 EP 14831 DI 10.1029/95JA00521 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400029 ER PT J AU FELDMAN, WC HONES, EW BARRACLOUGH, BL REEVES, GD BELIAN, RD CAYTON, TE LEE, P LEPPING, RP TROMBKA, JI STARR, R MOERSCH, J SQUYRES, SW RICH, FJ AF FELDMAN, WC HONES, EW BARRACLOUGH, BL REEVES, GD BELIAN, RD CAYTON, TE LEE, P LEPPING, RP TROMBKA, JI STARR, R MOERSCH, J SQUYRES, SW RICH, FJ TI POSSIBLE CONJUGATE RECONNECTION AT THE HIGH-LATITUDE MAGNETOPAUSE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-PRECIPITATION; MAGNETIC-FIELD; BOUNDARY-LAYER; RELATIVISTIC ELECTRONS; MAGNETOSPHERE; INTERPLANETARY; TRANSMITTER; RADIATION; EMISSIONS; MODEL AB Coordinated analysis of data sets from X ray, energetic electron, ionospheric convection velocity, interplanetary magnetic field (IMF), and solar wind plasma experiments yields a comprehensive picture of the stimulated precipitation of trapped relativistic electrons simultaneously onto both polar caps in response to a sharp northward-dawnward turning of the IMF after initiation of a substorm at about 1200 UT on December 17, 1992. Although several explanations are possible, these observations are consistent with the occurrence of conjugate magnetic reconnection tailward of both geomagnetic cusps caused by the draping of northward and dawnward directed IMF over the dayside magnetopause. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. CORNELL UNIV,CTR RADIOPHYS & SPACE RES,ITHACA,NY 14853. PHILLIPS LAB,BEDFORD,MA 01731. CATHOLIC UNIV AMER,WASHINGTON,DC 20064. RP FELDMAN, WC (reprint author), LOS ALAMOS NATL LAB,MS-D466,LOS ALAMOS,NM 87545, USA. RI Moersch, Jeffrey/F-7189-2010; Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 34 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD AUG 1 PY 1995 VL 100 IS A8 BP 14913 EP 14923 DI 10.1029/95JA01217 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RN064 UT WOS:A1995RN06400037 ER PT J AU VANFOSSEN, GJ SIMONEAU, RJ CHING, CY AF VANFOSSEN, GJ SIMONEAU, RJ CHING, CY TI INFLUENCE OF TURBULENCE PARAMETERS, REYNOLDS-NUMBER, AND BODY SHAPE ON STAGNATION-REGION HEAT-TRANSFER SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE FORCED CONVECTION; MODELING AND SCALING; TURBULENCE AB This experiment investigated the effects of free-stream turbulence intensity, length scale, Reynolds number, and leading-edge velocity gradient on stagnation-region heat transfer. Hear transfer was measured in the stagnation region of four models with elliptical leading edges downstream of five turbulence-generating grids. Stagnation-region heat transfer augmentation increased with decreasing length scale but an optimum scale was not found. A correlation was developed that fit heat transfer data for isotropic turbulence to within +/-4 percent but did not predict data for anisotropic turbulence. Stagnation heat transfer augmentation caused by turbulence was unaffected by the velocity gradient. The data of other researchers compared well with the correlation. A method of predicting heat transfer downstream of the stagnation point was developed. C1 SYRACUSE UNIV,SYRACUSE,NY. RP VANFOSSEN, GJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 31 TC 27 Z9 27 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 1995 VL 117 IS 3 BP 597 EP 603 DI 10.1115/1.2822619 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RX547 UT WOS:A1995RX54700006 ER PT J AU KAMOTANI, Y OSTRACH, S PLINE, A AF KAMOTANI, Y OSTRACH, S PLINE, A TI A THERMOCAPILLARY CONVECTION EXPERIMENT IN MICROGRAVITY SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE MICROGRAVITY HEAT TRANSFER; THERMOCAPILLARY FLOWS ID CRYSTAL-GROWTH PROCESS; MARANGONI NUMBER CONVECTION; LIQUID BRIDGES; ENERGY STABILITY; SQUARE CAVITY; MODEL; INSTABILITIES; SURFACE AB Results are reported of the Surface Tension Driven Convection Experiment (STDCE) aboard the USML-1 Spacelab, which was launched on June 25, 1992. In the experiment, 10 cSt silicone oil was placed in an open 10-cm-dia circular container, which was 5 cm deep. The fluid was heated either by a cylindrical heater (1.11 cm diameter) located along the container centerline or by a CO2 laser beam to induce thermocapillary flow. Several thermistor probes were placed in the fluid to measure the temperature distribution. The temperature distribution along the liquid-free surface was measured by an infrared imager. Tests were conducted over a range of heating powers, laser-beam diameters, and free surface shapes. An extensive numerical modeling of the flow was conducted in conjunction with the experiments. Some results of the temperature measurements with fiat free surfaces are presented in this paper and they are shown to agree well with the numerical predictions. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP KAMOTANI, Y (reprint author), CASE WESTERN RESERVE UNIV,DEPT MECH & AEROSP ENGN,CLEVELAND,OH 44106, USA. NR 25 TC 22 Z9 23 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 1995 VL 117 IS 3 BP 611 EP 618 DI 10.1115/1.2822621 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RX547 UT WOS:A1995RX54700008 ER PT J AU PARTHASARATHY, G LEE, HS CHAI, JC PATANKAR, SV AF PARTHASARATHY, G LEE, HS CHAI, JC PATANKAR, SV TI MONTE-CARLO SOLUTIONS FOR RADIATIVE HEAT-TRANSFER IN IRREGULAR 2-DIMENSIONAL GEOMETRIES SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Note C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP PARTHASARATHY, G (reprint author), UNIV MINNESOTA,DEPT ENGN MECH,MINNEAPOLIS,MN 55455, USA. RI Chai, John/A-3764-2010 NR 8 TC 20 Z9 20 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 1995 VL 117 IS 3 BP 792 EP 794 DI 10.1115/1.2822653 PG 3 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RX547 UT WOS:A1995RX54700040 ER PT J AU HAN, D KIM, YS NOZ, ME AF HAN, D KIM, YS NOZ, ME TI O(3,3)-LIKE SYMMETRIES OF COUPLED HARMONIC-OSCILLATORS SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID 2-PHOTON QUANTUM OPTICS; WIGNER PHASE-SPACE; SQUEEZED STATES; CANONICAL-TRANSFORMATIONS; FORMALISM; COHERENT AB In classical mechanics, the system of two coupled harmonic oscillators is shown to possess the symmetry of the Lorentz group O(3,3) or SL(4,r) in the four-dimensional phase space. In quantum mechanics, the symmetry is reduced to that of O(3,2) or Sp(4), which is a subgroup of O(3,3) or SL(4,r), respectively. It is shown that among the six Sp(4)-like subgroups, only one possesses the symmetry which can be translated into the group of unitary transformations in quantum mechanics. (C) 1995 American Institute of Physics. C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. NYU,DEPT RADIOL,NEW YORK,NY 10016. RP HAN, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 910 1,GREENBELT,MD 20771, USA. NR 32 TC 21 Z9 21 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD AUG PY 1995 VL 36 IS 8 BP 3940 EP 3954 DI 10.1063/1.530940 PG 15 WC Physics, Mathematical SC Physics GA RM885 UT WOS:A1995RM88500007 ER PT J AU VIKRAM, CS WITHEROW, WK TROLINGER, JD AF VIKRAM, CS WITHEROW, WK TROLINGER, JD TI FRINGE CONTRAST IN 2-COLOR HOLOGRAPHY IN THE PRESENCE OF A TRANSPARENT TEST MEDIUM SO JOURNAL OF MODERN OPTICS LA English DT Article AB The general theory of holographic fringe contrast in the presence of a transparent test cell in the object beam is presented. A specific case of triglycine sulphate aqueous solution with a concentration gradient in the test cell is also described in detail. The general irrationally related as well as frequency-doubled wavelengths for two-colour holography are considered and consequences on holographic fringes and their contrast are discussed. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. METROLASER,IRVINE,CA 92714. RP VIKRAM, CS (reprint author), UNIV ALABAMA,CTR APPL OPT,HUNTSVILLE,AL 35899, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD AUG PY 1995 VL 42 IS 8 BP 1665 EP 1676 DI 10.1080/09500349514551461 PG 12 WC Optics SC Optics GA RN929 UT WOS:A1995RN92900011 ER PT J AU ROBINSON, DH ARRIGO, KR ITURRIAGA, R SULLIVAN, CW AF ROBINSON, DH ARRIGO, KR ITURRIAGA, R SULLIVAN, CW TI MICROALGAL LIGHT-HARVESTING IN EXTREME LOW-LIGHT ENVIRONMENTS IN MCMURDO SOUND, ANTARCTICA SO JOURNAL OF PHYCOLOGY LA English DT Article DE ANTARCTIC; BENTHOS; CHROMATIC ADAPTATION; ICE ALGAE; PHOTOACCLIMATION; SEA ICE; SPECTRAL IRRADIANCE ID ICE MICROBIAL COMMUNITIES; COMPLEMENTARY CHROMATIC ADAPTATION; PHOTOSYNTHETIC ENERGY-CONVERSION; SEA-ICE; PHOTOSYSTEM-II; QUANTUM YIELD; ABSORPTION-SPECTRA; PHYSIOLOGICAL TEST; HIGH-RESOLUTION; ALGAE AB Microalgal pigment composition, photosynthetic characteristics, single-cell absorption efficiency (Qa((lambda))) spectra, and fluorescence-excitation (FE) spectra were determined for platelet ice and benthic communities underlying fast ice in McMurdo Sound, Antarctica, during austral spring 1988. Measurements for spectral irradiance (E((lambda))) and photosynthetically active radiation (PAR) as well as samples for particulate absorption measurements were taken directly under the congelation ice, within the platelet layer, as profiles vertically through the water column, and at the benthic surface. Light attenuation by sea ice, algal pigments, and particulates reduced PAR reaching the platelet ice layer to 3% (9-33 mu mol photons . m(-2). s(-1)) of surface values and narrowed its spectral distribution to a band between 400 and 580 nm. Attenuation by the water column further reduced PAR reaching the sea floor (28-m depth) to 0.05% of surface levels (<1 mu mol photons . m(-2). s(-1)), with a spectral distribution dominated by 470-580-nm wavelengths. The photoadaptive index (I-k) for platelet ice algae (5.9-12.6 mu mol photons . m(-2). s(-1)) was similar to ambient PAR, indicating that algae had acclimated to their light environment (i.e. the algae were light-replete). Maximum Qa(lambda) at the blue absorption peak (440 nm) was 0.63, and enhanced absorption was observed from 460-500 nm and was consistent with observed high cellular chlorophyll (chl) c : chl a and fucoxanthin : chl a molar ratios (0.4 and 1.2, respectively). Benthic algae were light-limited despite the maintenance of very low I-k values (4-11 mu mol photons . m(-2). s(-1)). Extremely high fucoxanthin : chl a ratios (1.6) in benthic algae produced enhanced green light absorption, resulting in a high degree of complementation between algal absorption and ambient spectral irradiance. Qa((lambda)) values for benthic algae were maximal (0.9) between 400 and 510 nm bet remained > 0.35 even at absorption minima. Strong spectral flattening, a characteristic of intense pigment packaging, was also apparent in the Qa(lambda) spectra for benthic algae. FE and Qa((lambda)) spectra were similar in shape for platelet ice algae, indicating that the efficiency at which absorbed energy was transferred to photosystem II (PSII) was independent of wavelength. fluorescence emission by benthic algae was greatest for 500-560-nm excitation wavelengths, suggesting that most energy absorbed by accessory pigments was transferred to PSII. These results suggest that under-ice algae employ complementary pigmentation and maximize absorption efficiency as adaptive strategies to low-light stress. Regulating the distribution of absorbed energy between PSI and PSII may be an adaptive response to the restricted spectral distribution of irradiance. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV SO CALIF,HANCOCK INST MARINE STUDIES,LOS ANGELES,CA 90089. RP ROBINSON, DH (reprint author), ALFRED WEGENER INST POLAR & MARINE RES,AM HANDELSHAFEN 12,D-27515 BREMERHAVEN,GERMANY. NR 63 TC 38 Z9 38 U1 2 U2 14 PU PHYCOLOGICAL SOC AMER INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD AUG PY 1995 VL 31 IS 4 BP 508 EP 520 DI 10.1111/j.1529-8817.1995.tb02544.x PG 13 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA RR626 UT WOS:A1995RR62600003 ER PT J AU WAJSOWICZ, RC AF WAJSOWICZ, RC TI THE RESPONSE OF THE INDO-PACIFIC THROUGHFLOW TO INTERANNUAL VARIATIONS IN THE PACIFIC WIND STRESS .1. IDEALIZED GEOMETRY AND VARIATIONS SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID DEPTH-INTEGRATED FLOW; INDONESIAN THROUGHFLOW; SOUTHERN OSCILLATION; OCEAN BOUNDARY; WORLD OCEAN; ATLANTIC; EXCHANGE; ISLAND; MODEL AB The effect of interannual variations in the Pacific wind stress on the barotropic and baroclinic components of the flow between the Pacific and Indian Oceans through the Indonesian Archipelago, the Indo-Pacific Throughflow, is investigated using a numerical ocean general circulation model (GCM) with a simplified geometry. In agreement with the modified Island Rule, variations in the depth-integrated throughflow are generated by zonal wind stress variations over the Pacific at the latitudes of the tips of the Australian continent, assuming the Pacific basin is flat bottomed. Wind stress variations at other latitudes generate variations in the depth-integrated transport only if they produce a depth-integrated pressure drop along the oceanic eastern boundary through the archipelago. From the Island Rule, alongshore wind stress variations on the west coasts of Australia and South America produce direct variations, but the observed signal is weak at interannual periods. Baroclinic variations in the throughflow are generated by baroclinic waves entering the archipelago, or by interaction between the barotropic component and the sills within the archipelago. Shallow sills within the archipelago are found to only partially block the throughflow. The dynamical constraint, that quasi-steady flow is parallel to f/H contours, is relaxed by weak friction; the reduction in throughflow is only 30% for sills blocking 70% of the water column at 9 degrees S. In the absence of sills, the throughflow response to a southern midlatitude wind stress anomaly is purely barotropic at interannual periods. Sills within the archipelago induce a baroclinic adjustment resulting in a surface trapping of the transport, which is in phase with the wind stress variations. Also, the depth-integrated pressure gradient through the archipelago produced by the topographic upwelling and downwelling is always directed to reduce the magnitude of the throughflow. For equatorial wind stress variations, the associated equatorial baroclinic Rossby waves are partially scattered into the archipelago. Sills within the archipelago block the transmitted equatorial Rossby waves, which would enhance the throughflow except that the baroclinic response to the topographic upwelling and downwelling negates the effect for part of the forcing cycle. Nonlinearity in the eastern equatorial response to an oscillating equatorial wind stress anomaly results in a mean throughflow from the Pacific to Indian Ocean. The combined effect of equatorial and southern midlatitude wind stresses, as typified by climatological mean values, yields a throughflow that is reduced by the inclusion of sills within the archipelago. Finally, in a comparison with the response in a GCM with a wholly blocked archipelago, the heat content anomaly (measured as the temperature averaged over the upper 300 m) in the equatorial Pacific is similar. However, the heat content anomaly in the archipelago and Indian Ocean is typically five to ten times larger than the equatorial anomaly difference between GCMs with an open/partially open and blocked archipelago, This is attributable to the difference in widths between equatorial and coastal baroclinic waveguides. The result suggests that the effect of variations in the throughflow on the Southern Oscillation is most likely felt in the archipelago and Indian Ocean. C1 NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771. NR 30 TC 14 Z9 14 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanog. PD AUG PY 1995 VL 25 IS 8 BP 1805 EP 1826 DI 10.1175/1520-0485(1995)025<1805:TROTIP>2.0.CO;2 PG 22 WC Oceanography SC Oceanography GA RM509 UT WOS:A1995RM50900004 ER PT J AU COLBAUGH, R GLASS, K SERAJI, H AF COLBAUGH, R GLASS, K SERAJI, H TI PERFORMANCE-BASED ADAPTIVE TRACKING CONTROL OF ROBOT MANIPULATORS SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article ID CONFIGURATION CONTROL; CONTROL LAWS; SYSTEMS; ROBUSTNESS; MOTION AB This article presents two new adaptive schemes for the motion control of robot manipulators. The proposed controllers are very general and computationally efficient because they do not require knowledge of either the mathematical model or the parameter values of the manipulator dynamics, and are implemented without calculation of the robot inverse dynamics or inverse kinematic transformation. It is shown that the control strategies are globally stable in the presence of bounded disturbances, and that in the absence of disturbances the ultimate bound on the size of the tracking errors can be made arbitrarily small. Computer simulation results are given for a PUMA 560 manipulator, and demonstrate that accurate and robust trajectory tracking can be achieved by using the proposed controllers. Experimental results are presented for an IMI Zebra Zero manipulator and confirm that the control schemes provide a simple and effective means of obtaining high-performance trajectory tracking. (C) 1995 John Wiley & Sons, Inc. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP COLBAUGH, R (reprint author), NEW MEXICO STATE UNIV,DEPT MECH ENGN,LAS CRUCES,NM 88003, USA. NR 25 TC 10 Z9 10 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0741-2223 J9 J ROBOTIC SYST JI J. Robot. Syst. PD AUG PY 1995 VL 12 IS 8 BP 517 EP 530 DI 10.1002/rob.4620120802 PG 14 WC Robotics SC Robotics GA RJ020 UT WOS:A1995RJ02000001 ER PT J AU HOU, AY MOLOD, A AF HOU, AY MOLOD, A TI MODULATION OF DYNAMIC HEATING IN THE WINTER EXTRATROPICS ASSOCIATED WITH THE CROSS-EQUATORIAL HADLEY CIRCULATION SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERE; ANOMALIES; FLOW AB The hypothesis that the cross-equatorial Hadley circulation can modulate the poleward heat transport in the winter extratropics is investigated using the Goddard Earth Observing System (GEOS-1) GCM for 10 northern winter initial conditions. Three-month forecasts are compared with parallel runs from the same initial conditions but with a slightly perturbed radiative forcing in the Tropics. Analysis of the zonal-mean climates shows that, on timescales longer than a month, a persistent intensification in the winter Hadley circulation is positively correlated with increased dynamic cooling in the winter midlatitudes and warming at the high latitudes throughout the troposphere, signaling an increased heat transport toward the winter pole. While the heating anomaly can undergo significant transient fluctuations in the winter extratropics, the variance of the time-averaged dynamic heating anomaly is dominated by contributions from low zonal wavenumbers (particularly wavenumbers 1 and 2), with minor contributions from wavenumbers 4 and higher, suggesting that the low-frequency planetary-scale waves are the primary vehicle for the increased poleward heat transport, with the synoptic-scale waves assuming a secondary role along the storm tracks. These results support the earlier idealized GCM study by Hou showing that a stronger winter Hadley circulation induced by a latitudinal shift in tropical convection can lead to enhanced upper-level tropical easterlies and a slightly stronger subtropical winter jet attended by increased poleward heat transport in the winter extratropics. Specific examples were also found in which the zonally averaged response is dominated by regional changes (notably over the North Pacific), indicating these relations may hold locally, as suggested by Bjerknes. The implication of this work is that the low-frequency variability in the Hadley circulation associated with persistent tropical rainfall anomalies may play an important role in global climate by modulating the subtropical wind shear and the energy available for baroclinic wave growth outside the Tropics. C1 GEN SCI CORP,LAUREL,MD. RP HOU, AY (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,DATA ASSIMILAT OFF,CODE 9103,GREENBELT,MD 20771, USA. RI Hou, Arthur/D-8578-2012 NR 25 TC 21 Z9 23 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD AUG 1 PY 1995 VL 52 IS 15 BP 2609 EP 2626 DI 10.1175/1520-0469(1995)052<2609:MODHIT>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RL815 UT WOS:A1995RL81500002 ER PT J AU BOGDANSKI, MS SLINEY, HE DELLACORTE, C AF BOGDANSKI, MS SLINEY, HE DELLACORTE, C TI THE EFFECT OF PROCESSING AND COMPOSITIONAL CHANGES ON THE TRIBOLOGY OF PM212 IN AIR SO LUBRICATION ENGINEERING LA English DT Article DE SELF-LUBRICATION; SOLID LUBRICATION AB The effects of processing and compositional variations on the tribological performance of PM212 were investigated. PM212 is a self-lubricating powder metallurgy composite comprised of a wear-resistant, metal-bonded chromium carbide matrix, containing the solid lubricants barium fluoride/calcium fluoride eutectic and silver. Several composites were formulated which had lubricant, matrix, and processing variations. Processing variations included sintering and hot isostatic pressing (HIPing). Pins fabricated from the composites were slid against superalloy disks in a pin-on-dish tribometer to study the tribological properties. Several composites exhibited low friction and wear in sliding against a nickel-based superalloy. The results showed that, under these test conditions, the tribological properties of PM212 are not highly sensitive to compositional and processing variations within the matrix studied. C1 CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,TRIOL GRP,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135. RP BOGDANSKI, MS (reprint author), PROCTER & GAMBLE CO,DIV PAPER PROD,CINCINNATI,OH, USA. NR 9 TC 9 Z9 9 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD AUG PY 1995 VL 51 IS 8 BP 675 EP 683 PG 9 WC Engineering, Mechanical SC Engineering GA RN330 UT WOS:A1995RN33000009 ER PT J AU BAGLEY, RL FREED, AD JONES, DIG AF BAGLEY, RL FREED, AD JONES, DIG TI A RENEWAL THEORY OF INELASTICITY SO MECHANICS OF MATERIALS LA English DT Article DE CREEP; PLASTICITY; VISCOPLASTICITY; INTRINSIC TIME; CONSTITUTIVE LAWS ID ENDOCHRONIC THEORY; YIELD-SURFACE; CYCLIC PLASTICITY; INTERNAL TIME; VISCOPLASTICITY; CREEP AB A uniaxial, high-temperature theory of inelastic deformation in metals and alloys is presented. The theory is based on a generalization of a creep theory to accommodate time-varying loads. The generalization is made possible through the concept of an ''intrinsic'' or ''internal'' time that arises from the mathematical theory of probability. The inelasticity theory is presented as a non-linear viscoelasticity theory and is used to predict the measured stress relaxation, stress-strain curves and load reversal response for a steel alloy. C1 NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135. TECHNOL SCI SERV INC,DAYTON,OH 45431. RP BAGLEY, RL (reprint author), USAF,WRIGHT LAB,FLIGHT DYNAM DIRECTORATE,DIV STRUCT,WRIGHT PATTERSON AFB,OH 45433, USA. OI Freed, Alan/0000-0002-3492-0628 NR 28 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD AUG PY 1995 VL 21 IS 2 BP 99 EP 117 DI 10.1016/0167-6636(95)00003-8 PG 19 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA RM928 UT WOS:A1995RM92800001 ER PT J AU ASTHANA, R TIWARI, R TEWARI, SN AF ASTHANA, R TIWARI, R TEWARI, SN TI INFLUENCE OF CR AND W ALLOYING ON THE FIBER-MATRIX INTERFACIAL SHEAR-STRENGTH IN CAST AND DIRECTIONALLY SOLIDIFIED SAPPHIRE NIAL COMPOSITES SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article AB Sapphire-reinforced NiAl matrix composites with chromium or tungsten as alloying additions were synthesized using casting and zone directional solidification (DS) techniques and characterized by a fiber pushout test as well as by microhardness measurements. The sapphire-NiAl(Cr) specimens exhibited an interlayer of Cr rich eutectic at the fiber-matrix interface and a higher interfacial shear strength compared to unalloyed sapphire-NiAl specimens processed under identical conditions. In contrast, the sapphire-NiAl(W) specimens did not show interfacial excess of tungsten rich phases, although the interfacial shear strength was high and comparable to that of sapphire-NiAl(Cr). The postdebond sliding stress was higher in sapphire-NiAl(Cr) than in sapphire-NiAl(W) due to interface enrichment with chromium particles. The matrix microhardness progressively decreased with increasing distance from the interface in both DS NiAl and NiAl(Cr) specimens. The study highlights the potential of casting and DS techniques to improve the toughness and strength of NiAl by designing dual-phase microstructures in NiAl alloys reinforced with sapphire fibers. C1 CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115. RP ASTHANA, R (reprint author), NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135, USA. NR 25 TC 10 Z9 10 U1 1 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD AUG PY 1995 VL 26 IS 8 BP 2175 EP 2184 DI 10.1007/BF02670688 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA RL362 UT WOS:A1995RL36200026 ER PT J AU CHOU, SH ATLAS, RM SHIE, CL ARDIZZONE, J AF CHOU, SH ATLAS, RM SHIE, CL ARDIZZONE, J TI ESTIMATES OF SURFACE HUMIDITY AND LATENT-HEAT FLUXES OVER OCEANS FROM SSM/I DATA SO MONTHLY WEATHER REVIEW LA English DT Article ID SENSOR MICROWAVE IMAGER; WESTERN EQUATORIAL PACIFIC; TOTAL PRECIPITABLE WATER; GLOBAL OCEANS; LEVEL HUMIDITY; SEA-SURFACE; WIND BURSTS; VARIABILITY; MOISTURE; PROFILES AB Monthly averages of daily latent heat fluxes over the oceans for February and August 1988 are estimated using a stability-dependent bulk scheme. Daily fluxes are computed from daily SSM/I (Special Sensor Microwave/Imager) wind speeds and EOF-retrieved SSM/I surface humidity, National Meteorological Center sea surface temperatures, and the European Centre for Medium-Range Weather Forecasts analyzed 2-m temperatures. Daily surface specific humidity (Q) is estimated from SSM/I precipitable water of total (W) and a 500-m bottom layer (W-B) using an EOF (empirical orthogonal function) method. This method has six W-based categories of EOFs (independent of geographical locations) and is developed using 23 177 FGGE IIb humidity soundings over the global oceans. For 1200 FGGE IIb humidity soundings, the accuracy of EOF-retrieved Q is 0.75 g kg(-1) for the case without errors in W and W-B and increases to 1.16 g kg(-1) for the case with errors in W and W-B. Compared to 342 collocated radiosonde observations, the EOF-retrieved SSM/I Q has an accuracy of 1.7 g kg(-1). The method improves upon the humidity retrieval of Liu and is competitive with that of Schulz et al. The SSM/I surface humidity and latent heat fluxes of these two months agree reasonably well with those of COADS (Comprehensive Ocean-Atmosphere Data Set). Compared to the COADS, the sea-air humidity difference of SSM/I has a positive bias of approximately 1-3 g kg(-1) (an overestimation of flux) over the wintertime trade wind belts and wintertime extratropical oceans. In the summertime extratropical Pacific and summertime eastern equatorial Pacific Ocean, it has a negative bias of about 1-2 g kg(-1) (an underestimation of flux). The results further suggest that the two monthly flux estimates, computed from daily and monthly mean data, do not differ significantly over the oceans. C1 SCI SYST & APPLICAT INC,LANHAM,MD. GEN SCI CORP,LAUREL,MD. RP CHOU, SH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE ATMOSPHER PROC BRANCH,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 35 TC 55 Z9 58 U1 2 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD AUG PY 1995 VL 123 IS 8 BP 2405 EP 2425 DI 10.1175/1520-0493(1995)123<2405:EOSHAL>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK480 UT WOS:A1995RK48000009 ER PT J AU LEE, SK PARK, J AF LEE, SK PARK, J TI DUAL-MODE DYNAMICS NEURAL-NETWORK FOR COMBINATORIAL OPTIMIZATION SO NEUROCOMPUTING LA English DT Article DE NEURAL OPTIMIZATION NETWORKS; COMBINATORIAL OPTIMIZATION; DUAL-MODE DYNAMICS; NEURAL NETWORK; N-QUEEN PROBLEM; KNAPSACK PROBLEM ID BIDIRECTIONAL ASSOCIATIVE MEMORIES; ALGORITHM AB This paper presents a new approach to solving combinatorial optimization problems based on a novel dynamic neural network featuring a dual-mode of network dynamics, the state dynamics and the weight dynamics. The network is referred to here as the dual-mode dynamics neural network (D2NN). Recently, neural network approaches have been studied for solutions to combinatorial optimization problems. There are two major difficulties in the neural network approaches. First, the objective function for a given problem must have the form that can be mapped onto the network, and secondly, due to the local minima problem, the quality of the solution is quite sensitive to various factors, such as the initial state and the parameters in the objective function. The proposed scheme overcomes these difficulties (1) by maintaining the objective function separately from the network energy function, rather than mapping it onto the network, and (2) by introducing a weight dynamics utilizing the objective function to overcome the local minima problem. The state dynamics defines state trajectories in a direction to minimize the network energy specified by the current weights and states, whereas the weight dynamics generates weight trajectories in a direction to minimize preassigned external objective function at a current state. D2NN is operated in such a way that the two modes of network dynamics alternately govern the network until an equilibrium is reached. The simulation results on the N-Queen problem and the knapsack problem indicate a superior performance of the D2NN. C1 UNIV SO CALIF,DEPT EE SYST & COMP SCI,LOS ANGELES,CA 90089. RP LEE, SK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-2312 J9 NEUROCOMPUTING JI Neurocomputing PD AUG PY 1995 VL 8 IS 3 BP 283 EP 304 DI 10.1016/0925-2312(94)00043-R PG 22 WC Computer Science, Artificial Intelligence SC Computer Science GA RQ640 UT WOS:A1995RQ64000004 ER PT J AU WURZ, P AELLIG, MR BOCHSLER, P GHIELMETTI, AG SHELLEY, EG FUSELIER, SA HERRERO, F SMITH, MF STEPHEN, TS AF WURZ, P AELLIG, MR BOCHSLER, P GHIELMETTI, AG SHELLEY, EG FUSELIER, SA HERRERO, F SMITH, MF STEPHEN, TS TI NEUTRAL ATOM IMAGING MASS SPECTROGRAPH SO OPTICAL ENGINEERING LA English DT Article DE NEUTRAL ATOMS; MAGNETOSPHERE; NEGATIVE IONS; REMOTE SENSING; MASS SPECTROGRAPH ID CHARGE-EXCHANGE; SURFACE COLLISIONS; HYDROGEN-IONS; CARBON FOILS; TIME; W(110) AB We describe a concept for an instrument to measure 2-D space plasma distributions by remote sensing of neutral atoms. The instrument measures in one dimension, and from a spinning spacecraft one obtains 2-D (line-of-sight) maps of the neutral flux. Because we want to employ this instrument for measurements in the magnetosphere, the main species of interest are neutral H and O atoms with kinetic energies ranging from about 10 eV to 1 keV. The instrument makes use of a low-work-function surface to convert neutral atoms efficiently to negative ions. The ions are then accelerated away from the surface and brought to an intermediate focus by a large aperture lens. After further acceleration, the ions are deflected by a spherical electrostatic analyzer into a time-of-flight mass spectrometer. Mass resolution of the device is sufficient to resolve H, D, He, and O. Energy and azimuth angle information are obtained by position imaging of the secondary electrons produced at the carbon foil. The large geometric factor combined with simultaneous angle-energy-mass measurement eliminates the need for cycling and provides the necessary high sensitivity for imaging at short time intervals. On a spinning spacecraft this instrument is capable of producing 2-D maps of low-energy neutral atom fluxes. C1 LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV DENVER,DENVER,CO 80208. RP WURZ, P (reprint author), UNIV BERN,INST PHYS,SIDLERSTR 5,CH-3012 BERN,SWITZERLAND. NR 40 TC 34 Z9 34 U1 1 U2 2 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD AUG PY 1995 VL 34 IS 8 BP 2365 EP 2376 DI 10.1117/12.205660 PG 12 WC Optics SC Optics GA RN199 UT WOS:A1995RN19900027 ER PT J AU MOROWITZ, H PETERSON, E CHANG, S AF MOROWITZ, H PETERSON, E CHANG, S TI THE SYNTHESIS OF GLUTAMIC-ACID IN THE ABSENCE OF ENZYMES - IMPLICATIONS FOR BIOGENESIS SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article AB This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis. C1 NASA,AMES RES CTR,PLANT BIOL BRANCH,MOFFETT FIELD,CA 94035. RP MOROWITZ, H (reprint author), GEORGE MASON UNIV,FAIRFAX,VA 22030, USA. NR 6 TC 12 Z9 12 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol Biosph. PD AUG PY 1995 VL 25 IS 4 BP 395 EP 399 DI 10.1007/BF01581777 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA RJ286 UT WOS:A1995RJ28600006 PM 11536704 ER PT J AU NESBITT, JA AF NESBITT, JA TI NUMERICAL MODELING OF HIGH-TEMPERATURE CORROSION PROCESSES SO OXIDATION OF METALS LA English DT Article DE MODELING; NUMERICAL MODELING; NUMERICAL TECHNIQUES; FINITE-DIFFERENCE TECHNIQUES; OXIDATION; CORROSION; CARBURIZATION; NITRIDATION; DIFFUSION ID PROTECTIVE SCALE FORMATION; SQUARE ROOT DIFFUSIVITY; NI-BASE ALLOYS; DESCRIBING CARBURIZATION; CYCLIC OXIDATION; AL; DEGRADATION; COATINGS AB Numerical modeling of the diffusional transport associated with high-temperature corrosion processes is reviewed. These corrosion processes include external scale formation and internal subscale formation during oxidation, coating degradation by oxidation and substrate interdiffusion, carburization, sulfidation and nitridation. The studies that are reviewed cover such complexities as concentration-dependent diffusivities, cross-term effects in ternary alloys, and internal precipitation where several compounds of the same element may form (e.g., carbides of Cr) or several compounds exist simultaneously (e.g., carbides containing varying amounts of Ni, CI, Fe or Mo). In addition, the studies involve a variety of boundary conditions that vary with time and temperature. Finite-difference (F-D) techniques have been applied almost exclusively to model either the salute or corrodant transport in each of these studies. Hence, the paper first reviews the use of F-D techniques to develop solutions to the diffusion equations with various boundary conditions appropriate to high-temperature corrosion processes. The bulk of the paper then reviews various F-D modeling studies of diffusional transport associated with high-temperature corrosion. RP NESBITT, JA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 39 TC 35 Z9 36 U1 2 U2 10 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0030-770X J9 OXID MET JI Oxid. Met. PD AUG PY 1995 VL 44 IS 1-2 BP 309 EP 338 DI 10.1007/BF01046731 PG 30 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA RQ461 UT WOS:A1995RQ46100012 ER PT J AU KAISER, MK HECHT, H AF KAISER, MK HECHT, H TI TIME-TO-PASSAGE JUDGMENTS IN NONCONSTANT OPTICAL FLOW FIELDS SO PERCEPTION & PSYCHOPHYSICS LA English DT Article; Proceedings Paper CT Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology CY MAY, 1994 CL SARASOTA, FL SP Assoc Res Vis & Ophthalmol ID EYE-MOVEMENTS; PERCEPTION; ACCELERATION; INFORMATION; COLLISION; VELOCITY; CONTACT; MOTION AB The time until an approaching object will pass an observer (time to passage, or TTP) is optically specified by a global flow field even in the absence of local expansion or size cues. Kaiser and Mowafy (1993) have demonstrated that observers are in fact sensitive to this global flow information. The present studies investigate two factors that are usually ignored in work related to TTP: (1) non-constant motion functions and (2) concomitant eye rotation. Non-constant velocities violate an assumption of some TTP derivations, and eye rotations may complicate heading extraction. Such factors have practical significance, for example, in the case of a pilot accelerating an aircraft or executing a roll. In our studies, a flow field of constant-sized stars was presented monocularly on a large screen. TTP judgments had to be made on the basis of one target star. The flow field varied in its acceleration pattern and its roll component. Observers did not appear to utilize acceleration information. In particular, TTPs with decelerating motion were consistently underestimated. TTP judgments were fairly robust with respect to roll, even when roll axis and track vector were decoupled. However, substantial decoupling between heading and track vector led to a decrement in performance, in both the presence and the absence of roll. RP KAISER, MK (reprint author), NASA,AMES RES CTR,MAIL STOP 262-2,MOFFETT FIELD,CA 94035, USA. RI Hecht, Heiko/H-3106-2011 NR 24 TC 30 Z9 30 U1 0 U2 1 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0031-5117 J9 PERCEPT PSYCHOPHYS JI Percept. Psychophys. PD AUG PY 1995 VL 57 IS 6 BP 817 EP 825 DI 10.3758/BF03206797 PG 9 WC Psychology; Psychology, Experimental SC Psychology GA RJ707 UT WOS:A1995RJ70700007 PM 7651806 ER PT J AU TENG, WL DORAISWAMY, PC WANG, JR AF TENG, WL DORAISWAMY, PC WANG, JR TI TEMPORAL VARIATIONS OF THE MICROWAVE POLARIZATION DIFFERENCE INDEX AND ITS RELATIONSHIP TO THE NORMALIZED DIFFERENCE VEGETATION INDEX IN A DENSELY CROPPED AREA SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID ANTECEDENT PRECIPITATION INDEX; SATELLITE DATA; SOIL-MOISTURE; AVHRR DATA; RADIOMETER; SMMR; DROUGHT; CORN AB The Microwave Polarization Difference Index (MPDI) for densely cropped areas contains information about the moisture and vegetation status of the ground surface. The surface parameters affecting MPDI and the relationship of MPDI to the Normalized Difference Vegetation Index (NDVI) vary seasonally To better understand this seasonal variation, MPDI derived from the Special Sensor Microwave/Imager and NDVI derived from the Advanced Very High Resolution Radiometer were geo-registered and compared with ground data and with each other. Analysis of MPDI time series showed that moisture effects dominated at the beginning of the growing season, vegetation effects dominated during the period of peak canopy cover and both effects were present at other times. MPDI was found to have an inverse, non-linear relationship with NDVI. MPDI varied more during the early part of the season, and NDVI varied more during the latter part of the season. Results were basically consistent with recent questions raised about the MPDI-vegetation relationship. The synergism between MPDI and NDVI is important for soil moisture and vegetation studies. C1 USDA ARS,REMOTE SENSING RES LAB,BELTSVILLE,MD 20705. RP TENG, WL (reprint author), HUGHES STX CORP,GODDARD SPACE FLIGHT CTR,CODE 902 2,GREENBELT,MD 20771, USA. NR 32 TC 9 Z9 9 U1 0 U2 1 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD AUG PY 1995 VL 61 IS 8 BP 1033 EP 1040 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA RN791 UT WOS:A1995RN79100008 ER PT J AU SCARPACI, JA CHAN, Y DIGREGORIO, D HARMON, BA POULIOT, J STOKSTAD, RG SURO, J AF SCARPACI, JA CHAN, Y DIGREGORIO, D HARMON, BA POULIOT, J STOKSTAD, RG SURO, J TI CENTRAL COLLISIONS IN THE O-16+C-12 REACTION AT 32.5 MEV/NUCLEON SO PHYSICAL REVIEW C LA English DT Article ID PHOSWICH DETECTOR; PERIPHERAL COLLISIONS; O-16 PROJECTILES; MEV NUCLEON; PARTICLES; EXCITATION AB Central collisions of O-16 on a C-12 target have been studied at 32.5 MeV/A. An analysis in terms of incomplete fusion followed by statistical decay is presented and the main channels for the incomplete fusion are extracted for this reaction. A detailed study of the specific channel, 5He+2H, shows a good agreement with a statistical decay of the Mg-24 parent nucleus while a multifragmentation model predicts a larger sphericity for these events. C1 INST PHYS NUCL LYON,F-91406 ORSAY,FRANCE. COMIS NACL ENERGIA ATOM,DEPT FIS,TANDAR,RA-1429 BUENOS AIRES,DF,ARGENTINA. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. UNIV LAVAL,PHYS NUCL LAB,QUEBEC CITY,PQ G1K 7P4,CANADA. UNIV NACL AUTONOMA MEXICO,INST FIS,MEXICO CITY 01000,DF,MEXICO. RP SCARPACI, JA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD AUG PY 1995 VL 52 IS 2 BP 764 EP 774 DI 10.1103/PhysRevC.52.764 PG 11 WC Physics, Nuclear SC Physics GA RQ227 UT WOS:A1995RQ22700041 ER PT J AU ZHOU, Y AF ZHOU, Y TI PHENOMENOLOGICAL TREATMENT OF ROTATING TURBULENCE SO PHYSICS OF FLUIDS LA English DT Note ID ISOTROPIC TURBULENCE AB In this Brief Communication, we first note the strong similarity between the magnetohydrodynamic (MHD) turbulence and initially isotropic turbulence subject to rotation. We then applied the MHD phenomenologies of Kraichnan [Phys. Fluids 8, 1385 (1965)] and Matthaeus and Zhou [Phys. Fluids B 1, 1929 (1989)] to rotating turbulence. We deduced a ''rule'' that relates spectral transfer time to the eddy turnover time and the time scale for decay of the triple correlations. Our hypothesis on the triple correlation decay rate leads to the spectral law, which varies between the ''-5/3'' (without rotation) and ''-2'' laws (with strong rotation). For intermediate rotation rates, the spectrum varies according to the value of a dimensionless parameter that measures the strength of the rotation wave number k(Omega)=Omega(3)/epsilon)(1/2) relative to the wave number k. The eddy viscosity is derived with an explicitly dependence on the rotation rate. (C) 1995 American Institute of Physics. RP ZHOU, Y (reprint author), NASA,LANGLEY RES CTR,INST COMP APPL SCI & ENGN,HAMPTON,VA 23681, USA. NR 20 TC 94 Z9 95 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 1995 VL 7 IS 8 BP 2092 EP 2094 DI 10.1063/1.868457 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RL706 UT WOS:A1995RL70600027 ER PT J AU BATTEN, JH STUTTE, GW WHEELER, RM AF BATTEN, JH STUTTE, GW WHEELER, RM TI EFFECT OF CROP DEVELOPMENT ON BIOGENIC EMISSIONS FROM PLANT-POPULATIONS GROWN IN CLOSED PLANT-GROWTH CHAMBERS SO PHYTOCHEMISTRY LA English DT Article DE TRITICUM AESTIVUM; GRAMINEAE; WHEAT; LACTUCA SATIVA; COMPOSITAE; LETTUCE; VOLATILES; FURAN; 2-METHYLFURAN; CARBON DISULFIDE; DIMETHYLSULFIDE; ISOPRENE; ALPHA-PINENE; 2-ETHYL-1-HEXANOL; 1-BUTANOL; NONANAL; BENZALDEHYDE; TETRAMETHYLUREA; TETRAMETHYLTHIOUREA ID VOLATILE COMPONENTS; CONTROLLED-ENVIRONMENT; LEAVES; SEED AB The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence. C1 DYNAMAC CORP,KENNEDY SPACE CTR,FL 32899. RP BATTEN, JH (reprint author), NASA,BIOL OPERAT & LIFE SUPPORT,MAIL CODE MD-RES,KENNEDY SPACE CTR,FL 32899, USA. NR 30 TC 22 Z9 24 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0031-9422 J9 PHYTOCHEMISTRY JI Phytochemistry PD AUG PY 1995 VL 39 IS 6 BP 1351 EP 1357 DI 10.1016/0031-9422(95)00126-R PG 7 WC Biochemistry & Molecular Biology; Plant Sciences SC Biochemistry & Molecular Biology; Plant Sciences GA RN858 UT WOS:A1995RN85800013 PM 7669278 ER PT J AU GRUN, E BAGUHL, M DIVINE, N FECHTIG, H HAMILTON, DP HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G SIDDIQUE, N STAUBACH, P ZOOK, HA AF GRUN, E BAGUHL, M DIVINE, N FECHTIG, H HAMILTON, DP HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G SIDDIQUE, N STAUBACH, P ZOOK, HA TI 3 YEARS OF GALILEO DUST DATA SO PLANETARY AND SPACE SCIENCE LA English DT Article AB From its launch in October 1989 until the end of 1992, the Galileo spacecraft traversed interplanetary space from Venus to the asteroid belt and successfully executed close flybys of Venus, the Earth, and the asteroid Gaspra. The dust instrument has been operating most of the time since it was switched on in December 1989. Except for short time intervals near Earth, data from the instrument were received via occasional(once per week to once per month) memory read outs containing 282-818 bytes of data. All events (impacts or noise events) were classified by an onboard program into 24 categories. Over the three-year time span, the dust detector recorded 469 ''big'' dust impacts. These were counted in 21 of the 24 event categories. The three remaining categories of very low amplitude events contain mostly noise events. The impact rate varied from 0.2 to 2 impacts per day depending on heliocentric distance and direction of spacecraft motion with respect to the interplanetary dust cloud. Because the average data transmission rate was very low, some data were not received on the ground. Complete data sets for 358 ''big'' impacts were received, but the other 111 ''big'' impacts were only counted. The observed impact rates are compared with a model of the meteoroid complex. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. LUND OBSERV,S-22100 LUND,SWEDEN. MAX PLANCK INST AERON,D-37191 KATLENBURG DUHM,GERMANY. UNIV KENT,CANTERBURY CT2 7NR,KENT,ENGLAND. MAX PLANCK INST EXTRATERR PHYS,D-85748 GARCHING,GERMANY. EUROPEAN SPACE TECHNOL CTR,2200 AG NOORDWIJK,NETHERLANDS. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP GRUN, E (reprint author), MAX PLANCK INST KERNPHYS,D-69029 HEIDELBERG,GERMANY. NR 16 TC 37 Z9 37 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD AUG PY 1995 VL 43 IS 8 BP 953 EP 969 DI 10.1016/0032-0633(94)00234-I PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT078 UT WOS:A1995RT07800002 ER PT J AU GRUN, E BAGUHL, M DIVINE, N FECHTIG, H HAMILTON, DP HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G SIDDIQUE, N STAUBACH, P ZOOK, HA AF GRUN, E BAGUHL, M DIVINE, N FECHTIG, H HAMILTON, DP HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G SIDDIQUE, N STAUBACH, P ZOOK, HA TI 2 YEARS OF ULYSSES DUST DATA SO PLANETARY AND SPACE SCIENCE LA English DT Article ID JUPITER; EJECTION; GALILEO; GRAINS AB From October 18, 1990 to February 8, 1992 the Ulysses spacecraft traversed interplanetary space between the Earth and Jupiter; at Jupiter the spacecraft was deflected below the ecliptic onto a highly-inclined orbit (i similar to 80 degrees). Here, we report on dust impact data obtained from launch until the end of 1992, nearly a year after the Jupiter flyby. During that time (792 days), the Ulysses dust detector recorded 968 impacts of dust particles with masses ranging from 10(-16) g to 10(-8) g. The impact rate varied from as low as one impact per week during quiet times to more than one per minute during the dust stream of March 10-11, 1992. In this paper, we present and describe the complete data set including both raw and reduced data. The performance of the sensor, which has been very satisfactory so far, is discussed in detail together with the noise discrimination scheme employed. The instrument's detection threshold is given as a function of both the particle's mass and its speed relative to Ulysses. The derived impact rates and the distribution of particle masses, speeds and impact directions are compared to a model of the meteoroid complex. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. LUND OBSERV,S-22100 LUND,SWEDEN. MAX PLANCK INST AERON,D-37191 KATLENBURG DUHM,GERMANY. UNIV KENT,CANTERBURY CT2 7NR,KENT,ENGLAND. MAX PLANCK INST EXTRATERR PHYS,D-85748 GARCHING,GERMANY. EUROPEAN SPACE TECHNOL CTR,2200 AG NOORDWIJK,NETHERLANDS. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP GRUN, E (reprint author), MAX PLANCK INST KERNPHYS,D-69029 HEIDELBERG,GERMANY. NR 24 TC 44 Z9 44 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD AUG PY 1995 VL 43 IS 8 BP 971 EP 999 DI 10.1016/0032-0633(94)00233-H PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RT078 UT WOS:A1995RT07800003 ER PT J AU GILES, AB JAHODA, K SWANK, JH ZHANG, W AF GILES, AB JAHODA, K SWANK, JH ZHANG, W TI PROSPECTS FOR COORDINATED OBSERVATIONS WITH XTE SO PUBLICATIONS ASTRONOMICAL SOCIETY OF AUSTRALIA LA English DT Article DE X-RAYS, GENERAL; INSTRUMENTATION, DETECTORS (XTE) ID RAY AB The X-ray Timing Explorer (XTE) is a NASA satellite designed to perform high-time-resolution studies of known X-ray sources. The two main experiments are a large-area proportional counter array (PCA) from the Goddard Space Flight Center (GSFC) and a high-energy X-ray timing experiment (HEXTE) from the University of California at San Diego (UCSD). The PCA data is processed by an electronic data system (EDS) built by the Massachusetts Institute of Technology (MIT) that performs many parallel processing analysis functions for on-board evaluation and data compression. MIT also provide an all-sky monitor (ASM) experiment so that XTE can be slewed rapidly to new transient sources. The spacecraft provides a mean science telemetry rate for the PCA of similar to 20 kilobits per second (kbps), with bursts to 256 kbps for durations of 30 minutes. Photons are tagged to 1 mu s and absolute timing should be better than 100 mu s XTE is due for launch in late August 1995 and the first NASA Research Announcement (NRA) is due out in January 1995. This paper summarises XTE's performance and then discusses the interactive and flexible operations of the satellite and some of the science it can do. These features should make XTE a productive spacecraft for coordinated observation programs. RP GILES, AB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 666,GREENBELT,MD 20771, USA. RI Jahoda, Keith/D-5616-2012; Swank, Jean/F-2693-2012 NR 17 TC 9 Z9 9 U1 0 U2 0 PU C S I R O PUBLICATIONS PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD VICTORIA 3066, AUSTRALIA SN 1323-3580 J9 PUBL ASTRON SOC AUST JI Publ. Astron. Soc. Aust. PD AUG PY 1995 VL 12 IS 2 BP 219 EP 226 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RV205 UT WOS:A1995RV20500014 ER PT J AU CUCINOTTA, FA WILSON, JW AF CUCINOTTA, FA WILSON, JW TI INITIATION-PROMOTION MODEL OF TUMOR PREVALENCE IN MICE FROM SPACE RADIATION EXPOSURES SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Heavy Ion Research - Space, Radiation Protection and Therapy CY MAR 21-24, 1994 CL SOPHIA ANTIPOLIS, FRANCE ID CARCINOGENESIS; ONCOGENE; MUTATION AB Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future. NASA missions, The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al, for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations. RP CUCINOTTA, FA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 15 TC 10 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD AUG PY 1995 VL 34 IS 3 BP 145 EP 149 DI 10.1007/BF01211540 PG 5 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA RN797 UT WOS:A1995RN79700004 PM 7480628 ER PT J AU TOWNSEND, LW CUCINOTTA, FA WILSON, JW AF TOWNSEND, LW CUCINOTTA, FA WILSON, JW TI THEORETICAL NUCLEAR DATABASE FOR HIGH-ENERGY, HEAVY-ION (HZE) TRANSPORT SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Heavy Ion Research - Space, Radiation Protection and Therapy CY MAR 21-24, 1994 CL SOPHIA ANTIPOLIS, FRANCE ID FRAGMENTATION; COLLISIONS; MODEL AB Theoretical methods for estimating high-energy, heavy-ion (HZE) particle absorption and fragmentation cross-sections are described and compared with available experimental data, Differences between theory and experiment range from several percent for absorption cross-sections up to about 25%-50% for fragmentation cross-sections. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 17 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD AUG PY 1995 VL 34 IS 3 BP 151 EP 154 DI 10.1007/BF01211541 PG 4 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA RN797 UT WOS:A1995RN79700005 PM 7480629 ER PT J AU SHINN, JL WILSON, JW SCHIMMERLING, W SHAVERS, MR MILLER, J BENTON, EV FRANK, AL BADAVI, FF AF SHINN, JL WILSON, JW SCHIMMERLING, W SHAVERS, MR MILLER, J BENTON, EV FRANK, AL BADAVI, FF TI A GREENS-FUNCTION METHOD FOR HEAVY-ION BEAM TRANSPORT SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Heavy Ion Research - Space, Radiation Protection and Therapy CY MAR 21-24, 1994 CL SOPHIA ANTIPOLIS, FRANCE ID 670A MEV NE-20; FRAGMENTATION; DEPTH; WATER AB The use of Green's function has played a fundamental role in transport calculations for high-charge high-energy (HZE) ions. Two recent developments have greatly advanced the practical aspects of implementation of these methods, The first was the formulation of a closed-form solution as a multiple fragmentation perturbation series, The second was the effective summation of the closed-form solution through nonperturbative techniques, The nonperturbative methods have been recently extended to an inhomogeneous, two-layer transport media to simulate the lead scattering foil present in the Lawrence Berkeley Laboratories (LBL) biomedical beam line used for cancer therapy. Such inhomogeneous codes are necessary for astronaut shielding in space. The transport codes utilize the Langley Research Center atomic and nuclear database. Transport code and database evaluation are performed by comparison with experiments performed at the LBL Bevalac facility using 670 A MeV Ne-20 and 600 A MeV Fe-56 ion beams. The comparison with a time-of-flight and Delta E detector measurement for the Ne-20 beam and the plastic nuclear track detectors for Fe-56 show agreement up to 35%-40% in water and aluminium targets, respectively. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV SAN FRANCISCO,SAN FRANCISCO,CA 94117. CHRISTOPHER NEWPORT UNIV,NEWPORT NEWS,VA 23601. RP SHINN, JL (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 13 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD AUG PY 1995 VL 34 IS 3 BP 155 EP 159 DI 10.1007/BF01211542 PG 5 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA RN797 UT WOS:A1995RN79700006 PM 7480630 ER PT J AU DURANTE, M GROSSI, GF GIALANELLA, G PUGLIESE, M NAPPO, M YANG, TC AF DURANTE, M GROSSI, GF GIALANELLA, G PUGLIESE, M NAPPO, M YANG, TC TI EFFECTS OF ALPHA-PARTICLES ON SURVIAL AND CHROMOSOMAL-ABERRATIONS IN HUMAN MAMMARY EPITHELIAL-CELLS SO RADIATION AND ENVIRONMENTAL BIOPHYSICS LA English DT Article ID C3H 10T1/2 CELLS; X-RAYS; HUMAN-LYMPHOCYTES; LUNG-CANCER; HEAVY-IONS; RADIOSENSITIVITY; RADIATION; DAMAGE; TRANSFORMATION; IRRADIATION AB We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell Line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/mu m] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D-0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gp; D-0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET a-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linear-quadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges. The RBE for the induction of total chromosome aberrations (2.3 at 37% cell survival) was lower than that for cell survival, suggesting that chromosome damage at the first postirradiation mitosis is not sufficient to account for the increased efficiency of alpha-particles in the induction of lethal effects. However, measured cell survival after alpha-particle irradiation can be predicted from chromosome damage when cells at differ ent population doubling numbers after irradiation are considered. In fact, a high percentage of alpha-irradiated cells carried unstable chromosomal aberrations up to population doubling number about 5. On the other hand, x-ray-induced damage disappeared rapidly. These results suggest that alpha-particle-induced reproductive death of human mammary epithelial cells is caused by chromosome damage in the first 5 generations following exposure, whereas the inactivation produced by low-LET radiation is mostly related to the aberrations at the first post-irradiation mitosis. C1 UNIV NAPLES FEDERICO II,DIPARTIMENTO SCI FIS,I-80125 NAPLES,ITALY. IST NAZL FIS NUCL,I-80125 NAPLES,ITALY. NASA,LYNDON B JOHNSON SPACE CTR,DIV MED SCI,HOUSTON,TX 77058. RI Durante, Marco/K-1315-2014; OI Durante, Marco/0000-0002-4615-553X NR 39 TC 22 Z9 22 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-634X J9 RADIAT ENVIRON BIOPH JI Radiat. Environ. Biophys. PD AUG PY 1995 VL 34 IS 3 BP 195 EP 204 DI 10.1007/BF01211548 PG 10 WC Biology; Biophysics; Environmental Sciences; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Environmental Sciences & Ecology; Radiology, Nuclear Medicine & Medical Imaging GA RN797 UT WOS:A1995RN79700012 PM 7480636 ER PT J AU FELDMAN, SC PELLETIER, RE WALSER, E SMOOT, JC AHL, D AF FELDMAN, SC PELLETIER, RE WALSER, E SMOOT, JC AHL, D TI A PROTOTYPE FOR PIPELINE ROUTING USING REMOTELY-SENSED DATA AND GEOGRAPHIC INFORMATION-SYSTEM ANALYSIS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB A prototype least cost analysis was performed for pipeline routing using remotely sensed data and GIS analysis. A snail section of the proposed Caspian oil pipeline was chosen for development of the prototype. The entire proposed 700-km Caspian pipeline would connect with existing pipelines and carry oil from the Tengiz oil field in Kazakhstan, on the Caspian Sea, to Novorossiysk in Russia, on the Black Sea. A model was developed incorporating pipeline length, topography, geology, land use, and stream, wetland, road, and railroad crossings to identify a least cost pathway. Satellite remote sensing imagery was used as a base to display results and to define the land cover. Geographic Information System (GIS) analysis was used for spatial modeling and data overlay. Costs associated with terrain conditions, geology, and land use were calculated from actual costs on a recent Bechtel pipeline project. The length and cost associated with a straight line path between four predetermined points along a section of the pipeline were compared with the length and cost of the least cost pathway. The straight line path was 42 km long, and the least cost pathway was 51 km long. Although longer in length, the least cost pathway (in the area considered) is 14% less expensive to construct than the straight line path. The least cost pathway realizes savings principally by avoiding higher cost urban and industrial cells on the straight line route. The results of this analysis demonstrate the benefits of integrating remotely sensed data with GIS analysis as a first look for pipeline routing. C1 NASA,COMMERCIAL REMOTE SENSING OFF,BAY ST LOUIS,MS. LOCKHEED STENNIS OPERAT,BAY ST LOUIS,MS. RP FELDMAN, SC (reprint author), BECHTEL CORP,50 BEALE ST,SAN FRANCISCO,CA 94105, USA. NR 11 TC 26 Z9 28 U1 1 U2 12 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD AUG PY 1995 VL 53 IS 2 BP 123 EP 131 DI 10.1016/0034-4257(95)00047-5 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RR224 UT WOS:A1995RR22400009 ER PT J AU MIURA, H CHARGIN, M AF MIURA, H CHARGIN, M TI APPROXIMATION OF FREQUENCY RESPONSES BASED ON LARSSONS METHOD SO STRUCTURAL OPTIMIZATION LA English DT Article AB This paper discusses the new aspects of the formulation for structural model updates presented by Larsson and Sas at the 10th International Modal Analysis Conference held in San Diego, California in February 1991. First, a closed-form representation of the reduced impedance matrix is presented. It clarifies the issues associated with the range of the excitation frequencies used in model updates. Second, the applicable range of excitation frequencies is considered through an example where low frequency local modes are present. Third, the computational aspects of this algorithm are studied. It is shown that displacement sensitivity vectors corresponding to the virtual loads are critical in the computation of the reduced impedance matrix sensitivity. Finally, applicability of this algorithm for approximate frequency responses in structural optimization is studied. Numerical results are included to illustrate the essence of this formulation. RP MIURA, H (reprint author), NASA,AMES RES CTR,SYST ANAL BRANCH,MS 237-11,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0934-4373 J9 STRUCT OPTIMIZATION JI Struct. Optim. PD AUG PY 1995 VL 10 IS 1 BP 9 EP 15 DI 10.1007/BF01743690 PG 7 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Mechanics SC Computer Science; Engineering; Mechanics GA RT323 UT WOS:A1995RT32300002 ER PT J AU SMITH, WL AF SMITH, WL TI NASA THINKS SMALL SO TECHNOLOGY REVIEW LA English DT Letter RP SMITH, WL (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MASS INST TECHNOL PI CAMBRIDGE PA CAMBRIDGE, MA 02139 SN 0040-1692 J9 TECHNOL REV JI Technol. Rev. PD AUG-SEP PY 1995 VL 98 IS 6 BP 6 EP 6 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RL926 UT WOS:A1995RL92600002 ER PT J AU CHEESEMAN, P AF CHEESEMAN, P TI FUZZY THINKING - DISCUSSION SO TECHNOMETRICS LA English DT Note RP CHEESEMAN, P (reprint author), NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035, USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER STATIST ASSN PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD AUG PY 1995 VL 37 IS 3 BP 282 EP 283 DI 10.2307/1269910 PG 2 WC Statistics & Probability SC Mathematics GA RK826 UT WOS:A1995RK82600006 ER PT J AU RICCA, A BAUSCHLICHER, CW AF RICCA, A BAUSCHLICHER, CW TI A COMPARISON OF DENSITY-FUNCTIONAL THEORY WITH AB-INITIO APPROACHES FOR SYSTEMS INVOLVING FIRST TRANSITION ROW METALS SO THEORETICA CHIMICA ACTA LA English DT Article DE DENSITY FUNCTIONAL THEORY; B3LYP; TRANSITION METALS; BINDING ENERGY ID COLLISION-INDUCED DISSOCIATION; ELECTRON CORRELATION; CORRELATION ENERGIES; BINDING-ENERGIES; WATER-MOLECULES; IONS; EXCHANGE; ATOMS; 1ST AB Density functional theory (DFT), using the B3LYP hybrid functional is found to give a better description of the geometries and vibrational frequencies of FeL and FeL(+) systems that second-order Mailer Plesset perturbation theory (MP2). Namely, DFT correctly predicts the shift in the CO vibrational frequency between free CO and the (5) Sigma(-) State of FeCO and yields a good result for the Fe-C distance in the quartet states of FeCH4+. These are properties where the MP2 results are unsatisfactory. Thus DFT appears to be an excellent approach for optimizing the geometries and computing the zero-point energies of systems containing first transition row atoms. Because the DFT approach is biased in favor of the 3d(7) occupation, whereas the more traditional approaches are biased in favor of the 3d(6) occupation, differences are found in the relative ordering of states. It is shown that if the dissociation energy is computed relative to the most appropriate atomic asymptote and corrected to the ground state asymptote using the experimental separations, the DFT results are in good agreement with high levels of theory. The energetics at the DFT level are much superior to MP2 and in most cases they are in good agreement with high levels of theory. RP RICCA, A (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 30 TC 133 Z9 136 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD AUG PY 1995 VL 92 IS 2 BP 123 EP 131 PG 9 WC Chemistry, Physical SC Chemistry GA RQ464 UT WOS:A1995RQ46400005 ER PT J AU ASKER, JR AF ASKER, JR TI MISSION CONTROL EASES ONTO NETWORK SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Article RP ASKER, JR (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD JUL 31 PY 1995 VL 143 IS 5 BP 56 EP 57 PG 2 WC Engineering, Aerospace SC Engineering GA RL635 UT WOS:A1995RL63500037 ER PT J AU BRADLEY, DS VONMEERWALL, ED ROBERTS, GD KAMVOURIS, J AF BRADLEY, DS VONMEERWALL, ED ROBERTS, GD KAMVOURIS, J TI NMR RELAXATION STUDY OF THERMAL-DEGRADATION IN CURED PMR POLYIMIDES SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE NMR RELAXATION; PMR POLYIMIDES; THERMAL DEGRADATION ID NUCLEAR MAGNETIC-RESONANCE; END-CAPPED POLYIMIDES; MOLECULAR MOBILITY; N-PHENYLNADIMIDE; COMPOSITES; POLYMERIZATION; GENERATION; DIFFUSION; STRAINS; VOLATILES AB We have studied cross-linking and thermal degradation of high-performance first- and second-generation PMR-15 polyimides, both thermoset and thermoplastic versions, by performing nonspectroscopic NMR solid echo T-2* relaxation measurements at temperatures up to 430 degrees C using probes built for this purpose. We employ signal averaging and automated decomposition of the relaxation decays into two Gaussian components, the slower of which gradually appears above 300 degrees C. Tracking the molecular mobility spectrum in terms of the relative intensity of the components and their relaxation times as temperature is cycled, we detect essentially no irreversible effects below the glass transition, measure permanent mobility reductions attributable to completion of cure, and find that exposure to temperatures above 380 degrees C on the order of 1 h is required for substantial thermal degradation to occur. These results are closely supported by thermal and mechanical measurements on parallel specimens. Second-generation PMR resins appear to have higher microscopic rigidity and reduced viscous fraction at high temperatures. (C) 1995 John Wiley & Sons, Inc. C1 UNIV AKRON,DEPT PHYS,AKRON,OH 44325. UNIV AKRON,MAURICE MORTON INST POLYMER SCI,AKRON,OH 44325. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 34 TC 9 Z9 9 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JUL 30 PY 1995 VL 33 IS 10 BP 1545 EP 1557 DI 10.1002/polb.1995.090331012 PG 13 WC Polymer Science SC Polymer Science GA RC148 UT WOS:A1995RC14800012 ER PT J AU PEROT, B MOIN, P AF PEROT, B MOIN, P TI SHEAR-FREE TURBULENT BOUNDARY-LAYERS .1. PHYSICAL INSIGHTS INTO NEAR-WALL TURBULENCE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID FRACTIONAL-STEP METHOD; MODEL AB Direct numerical simulation is used to examine the interaction of turbulence with a wall in the absence of mean shear. The influence of a solid wall on turbulence is analysed by first considering two 'simpler' types of boundaries. The first boundary is an idealized permeable wall. This boundary isolates and elucidates the viscous effects created by the wall. The second boundary is an idealized free surface. This boundary complements the first by allowing one to isolate and investigate the kinematic effects that occur near boundaries. The knowledge gained from these two simpler flows is then used to understand how turbulence is influenced by solid walls where both viscous and kinematic effects occur in combination. Examination of the instantaneous flow fields confirms the presence of previously hypothesized structures (splats), and reveals an additional class of structures (antisplats). Statistical analysis of the Reynolds stresses and Reynolds stress transport equations indicates the relative importance of dissipation, intercomponent energy transfer, and energy transport. It is found that it is not the structures themselves, but the imbalance between structures which leads to intercomponent energy transfer. Remarkably, this imbalance (and hence near-wall intercomponent energy transfer) is controlled by viscous processes such as dissipation and diffusion. The analysis presented herein is a departure from past notions of how boundaries influence turbulence. The efficacy of these qualitative physical concepts is demonstrated in Part 2 where improved near-wall turbulence models are derived based on these ideas. C1 STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 32 TC 117 Z9 117 U1 3 U2 8 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 25 PY 1995 VL 295 BP 199 EP 227 DI 10.1017/S0022112095001935 PG 29 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RM816 UT WOS:A1995RM81600008 ER PT J AU PEROT, B MOIN, P AF PEROT, B MOIN, P TI SHEAR-FREE TURBULENT BOUNDARY-LAYERS .2. NEW CONCEPTS FOR REYNOLDS STRESS TRANSPORT-EQUATION MODELING OF INHOMOGENEOUS FLOWS SO JOURNAL OF FLUID MECHANICS LA English DT Article ID NEAR-WALL TURBULENCE; DISSIPATION; CLOSURE AB Models for the dissipation tenser and (slow) pressure-strain terms of the Reynolds stress transport equations are presented which are applicable near boundaries. These models take into account the large inhomogeneity and anisotropy that can be present near walls and surfaces, and are inspired by the physical insights developed in Part 1 of this paper. The dissipation tenser model represents a fundamentally new approach to dealing with turbulence inhomogeneities. The pressure-strain model shows how the classic return-to-isotropy model of Lumley (1978) can be adapted to the near-wall region. The closure hypotheses underlying these two models are tested in an a priori fashion using direct numerical simulation (DNS) data. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. NR 22 TC 12 Z9 12 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 25 PY 1995 VL 295 BP 229 EP 245 DI 10.1017/S0022112095001947 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RM816 UT WOS:A1995RM81600009 ER PT J AU CHAMBERS, JG TAYLOR, LA PATCHEN, A MCKAY, DS AF CHAMBERS, JG TAYLOR, LA PATCHEN, A MCKAY, DS TI QUANTITATIVE MINERALOGICAL CHARACTERIZATION OF LUNAR HIGH-TI MARE BASALTS AND SOILS FOR OXYGEN PRODUCTION SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB Efficient lunar resource utilization requires accurate and quantitative evaluation of mineral and glass abundances, distribution, and extraction feasibility, especially for ilmenite. With this in mind, true modal analyses were performed on high-Ti mare basalts and soils with X ray/backscattered electron signal digital-imaging techniques, and these data indicate that (1) ilmenite concentrations are similar for basalts and immature-submature soils with similar TiO2 content; (2) ilmenite liberation of crushed mare basalts and immature-submature mare soils are comparable (i.e., both contain similar amounts of free ilmenite); and (3) because of impact melting and agglutination of primary minerals, mature mare soils contain less ilmenite (both free and attached). Modal analyses of magnetic separates of high-Ti mare basalts and soils show that (1) ilmenite was concentrated by a factor of greater than or equal to 3.3 and (2) soil ilmenite was concentrated to factors of 1.7-2.3. The lower soil ilmenite separation efficiency is attributed to Fe-o-bearing agglutinitic glass and amorphous rinds adhered to soil particles. Mass yields of magnetically generated feedstocks were generally less than 5 wt % in most cases. Calculation of oxygen yield (as released by hydrogen gas reduction of ilmenite) show that (1) beneficiated basalt will provide the most oxygen (8-10%), because of higher ilmenite concentration; (2) reduction of raw immature-submature mare soils and basalts will produce similar amounts of lunar liquid oxygen (LLOX) (2.1-3.1%); and (3) raw Fe-rich pyroclastic soil, 74220, will provide more oxygen (5.4%) than beneficiated high-Ti mare soils and half that of beneficiated high-Ti mare basalts. High-Ti mare soils are attractive resources for lunar liquid oxygen (LLOX) production because of their unconsolidated nature, high ilmenite abundance, and widespread occurrence. Energy-intensive excavation and comminution likely prohibits the basalt mining during early lunar occupation. Orange soils are important resources for LLOX and various volatile elements, but slower reaction kinetics and glass sintering pose potential difficulties for large-scale operations. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP CHAMBERS, JG (reprint author), UNIV TENNESSEE,INST PLANETARY GEOSCI,DEPT GEOL SCI,KNOXVILLE,TN 37996, USA. NR 48 TC 14 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUL 25 PY 1995 VL 100 IS E7 BP 14391 EP 14401 DI 10.1029/95JE00503 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL463 UT WOS:A1995RL46300003 ER PT J AU BLANEY, DL MCCORD, TB AF BLANEY, DL MCCORD, TB TI INDICATIONS OF SULFATE MINERALS IN THE MARTIAN SOIL FROM EARTHBASED SPECTROSCOPY SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS; CARBONATES; REFLECTANCE; SURFACE; SPECTRA; ORIGIN; DUST AB Telescopic measurements of Mars between 4.40 and 5.13 mu m at a spectral resolution (lambda/Delta lambda) of 300 were made on August 19, 1988, UT at the NASA infrared Telescope Facility on Mauna Kea, Hawaii. This wavelength region contains radiation from both solar reflection and thermal emission. Additionally, the Martian atmosphere has numerous atmospheric gas absorption features, dominated by the 4.2-mu m CO2 fundamental band. The Mars spectrum rise out of the 4.2 to 4.4-mu m CO2 band on the long-wavelength side cannot be matched solely by atmospheric gas constituents. An absorption must be added at roughly 4.5 mu m in order to decrease the reflectance rise and produce the 4.5-mu m inflection which is present in the data. The location of this feature at the position of the 2 nu 3 overtone of the SO42- anion indicates that the surface absorption is probably caused by sulfates on the Martian surface and/or in atmospheric dust, This is consistent with the known presence of sulfates on the Martian surface from the Viking results. An exact spectral match to a terrestrial sulfur mineral has not been made, but we suggest that the mineral on Mars has very weak band structure, probably due to an ion environment in the mineral with a high degree of electric field symmetry. Significant variation exists at 4.5 mu m among the observed spectra for different locations on Mars. In order of strength, from strongest absorption to weakest, are Eastern Solis Planum, Argyre Basin, Eastern Tharsis, and Valles Marineris for the four regions measured at similar Mars atmospheric conditions. C1 UNIV HAWAII,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822. RP BLANEY, DL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 28 TC 40 Z9 41 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUL 25 PY 1995 VL 100 IS E7 BP 14433 EP 14441 DI 10.1029/95JE00224 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL463 UT WOS:A1995RL46300006 ER PT J AU DODELSON, S KOSOWSKY, A AF DODELSON, S KOSOWSKY, A TI ANALYSIS OF SMALL-SCALE AND MEDIUM-SCALE COSMIC MICROWAVE BACKGROUND MEASUREMENTS SO PHYSICAL REVIEW LETTERS LA English DT Article ID DEGREE ANGULAR SCALES; RADIATION ANISOTROPY; DARK MATTER; COBE; UNIVERSE AB Anisotropies in the temperature of the cosmic microwave background have been detected on a range of scales by several different experiments. In principle, the largest barrier to a clean interpretation of the experimental results is contamination by foreground sources. We address this issue by projecting out likely sources of foreground contamination from seven separate small-angle and medium-angle experiments. All of the experiments are consistent so far with the simplest inflationary models; for n = 1 the experiments' combined best-fit quadrupole amplitude is Q(rms-ps) = 18(-1)(+3) mu K, in excellent agreement with the Cosmic Background Explorer two-year data. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. RP DODELSON, S (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 29 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 24 PY 1995 VL 75 IS 4 BP 604 EP 607 DI 10.1103/PhysRevLett.75.604 PG 4 WC Physics, Multidisciplinary SC Physics GA RK690 UT WOS:A1995RK69000004 ER PT J AU PAUL, W YOON, DY SMITH, GD AF PAUL, W YOON, DY SMITH, GD TI AN OPTIMIZED UNITED ATOM MODEL FOR SIMULATIONS OF POLYMETHYLENE MELTS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; SHORT-RANGE ORDER; SELF-DIFFUSION; POLYETHYLENE; POLYMERS; ALKANES; LIQUID; GLASS AB We present here an optimized united atom model that is able to reproduce properties of melts of n-alkane chains of varying molecular weights. This model differs from previous models in that the Lennard-Jones well depth for the terminal methyl group (0.2264 kcal/mol) differs from that of the methylene units (0.093 kcal/mol). The position of the minimum is at 4.5 Angstrom for both units. Properties of n-C44H90 melts from this model are compared with experiments and those from an explicit atom model. Good agreement with experiment is obtained for static properties of the melt, specifically P-V-T behavior, chain conformations, and x-ray scattering profiles. The large-scale dynamics, as measured by self-diffusion, are found to agree reasonably well with experimental results, being about 30% faster with our best united atom force field. Analysis of the end-to-end vector orientation autocorrelation function in terms of the Rouse model yields a monomer friction coefficient somewhat greater than that determined from the rate of self-diffusion, reflecting the fact that the n-C44H90 chains are not sufficiently long to behave as Gaussian coils. Detailed local chain dynamics for n-C44H90 melts, as measured by the P-1 (t) and P-2(t) orientation autocorrelation functions for C-H vectors, are found to agree reasonably well with results from simulations using an explicit atom model, and yield spin-lattice relaxation times T-1 and nuclear Overhauser enhancement values in reasonable agreement with experimental C-13 NMR measurements. As with large scale dynamics, local dynamics are faster in general (about 20%) than experimental results. (C) 1995 American Institute of Physics. C1 IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. NASA,AMES RES CTR,INST THERMOSCI,MOFFETT FIELD,CA 94035. UNIV MAINZ,INST PHYS,D-55099 MAINZ,GERMANY. NR 26 TC 177 Z9 179 U1 6 U2 33 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1995 VL 103 IS 4 BP 1702 EP 1709 DI 10.1063/1.469740 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RK378 UT WOS:A1995RK37800047 ER PT J AU RICCA, A BAUSCHLICHER, CW AF RICCA, A BAUSCHLICHER, CW TI THE LOW-LYING ELECTRONIC STATES OF LIB SO CHEMICAL PHYSICS LETTERS LA English DT Article ID IONS AB The spectroscopic constants for the triplet and singlet states of LiB below about 30000 cm(-1) are determined using an internally contracted multireference configuration-interaction approach. The ground state is (3) Pi as found in previous work. Transitions between the (3) Pi state and the (1)(3) Sigma(-), (2)(3) Pi, and (3)(3) Pi states are studied in detail. The (1)(3) Sigma(-) state is low-lying and may be hard to observe in many experimental approaches. The (2)(3) Pi and (3)(3) Pi states have bond lengths that are significantly longer than the ground state, resulting in transition intensities that are spread out over many vibrational levels of the ground state. RP RICCA, A (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 16 TC 10 Z9 10 U1 0 U2 0 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 JUL 21 PY 1995 VL 241 IS 3 BP 241 EP 247 DI 10.1016/0009-2614(95)00626-F PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RL181 UT WOS:A1995RL18100015 ER PT J AU BARNES, NP JANI, MG HUTCHESON, RL AF BARNES, NP JANI, MG HUTCHESON, RL TI DIODE-PUMPED, ROOM-TEMPERATURE TM-LUAG LASER SO APPLIED OPTICS LA English DT Article AB A diode-pumped, room-temperature Tm:LuAG laser demonstrated a total optical-to-optical efficiency of 0.073 and an optical-to-optical differential efficiency as high as 0.236. Laser performance and operating wavelength were investigated as a function of the Tm concentration. The highest laser output energy was achieved with a Tm concentration of 0.04 and at a wavelength of 2.0238 mu m. C1 SCI & TECHNOL CORP,HAMPTON,VA 23665. SCI MAT CORP,BOZEMAN,MT 59715. RP BARNES, NP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 13 TC 42 Z9 42 U1 3 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 1995 VL 34 IS 21 BP 4290 EP 4294 PG 5 WC Optics SC Optics GA RL129 UT WOS:A1995RL12900017 PM 21052259 ER PT J AU JOINER, J BHARTIA, PK CEBULA, RP HILSENRATH, E MCPETERS, RD PARK, H AF JOINER, J BHARTIA, PK CEBULA, RP HILSENRATH, E MCPETERS, RD PARK, H TI ROTATIONAL RAMAN-SCATTERING (RING EFFECT) IN SATELLITE BACKSCATTER ULTRAVIOLET MEASUREMENTS SO APPLIED OPTICS LA English DT Article DE ROTATIONAL RAMAN SCATTERING; SATELLITE ULTRAVIOLET ID IRRADIANCE COMPARISON EXPERIMENT-1; ABSORPTION-MEASUREMENTS; OZONE; SKY AB A detailed radiative transfer calculation has been carried out to estimate the effects of rotational Raman scattering (RRS) on satellite measurements of backscattered ultraviolet radiation. Raman-scattered light is shifted in frequency from the incident light, which causes filling in of solar Fraunhofer lines in the observed backscattered spectrum (also known as the Ring effect). The magnitude of the rotational Raman scattering filling in is a function of wavelength, solar zenith angle, surface reflectance, surface pressure, and instrument spectral resolution. The filling in predicted by our model is found to be in agreement with observations from the Shuttle Solar Backscatter Ultraviolet Radiometer and the Nimbus-7 Solar Backscatter Ultraviolet Radiometer. C1 HUGHES STX CORP,GREENBELT,MD 20770. RP JOINER, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. RI Joiner, Joanna/D-6264-2012; McPeters, Richard/G-4955-2013; Bhartia, Pawan/A-4209-2016 OI McPeters, Richard/0000-0002-8926-8462; Bhartia, Pawan/0000-0001-8307-9137 NR 25 TC 86 Z9 87 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 1995 VL 34 IS 21 BP 4513 EP 4525 PG 13 WC Optics SC Optics GA RL129 UT WOS:A1995RL12900042 PM 21052284 ER PT J AU MISHCHENKO, MI MACKOWSKI, DW TRAVIS, LD AF MISHCHENKO, MI MACKOWSKI, DW TRAVIS, LD TI SCATTERING OF LIGHT BY BISPHERES WITH TOUCHING AND SEPARATED COMPONENTS SO APPLIED OPTICS LA English DT Article DE LIGHT SCATTERING; NONSPHERICAL PARTICLES; COOPERATIVE EFFECTS; DEPOLARIZATION; MULTIPLE SCATTERING ID AXIALLY-SYMMETRICAL PARTICLES; SIZE SHAPE DISTRIBUTIONS; ELECTROMAGNETIC SCATTERING; DIELECTRIC SPHERES; T-MATRIX; WAVELENGTH; SYSTEMS AB We use the T-matrix method as described by Mishchenko and Mackowski [Opt. Lett. 19, 1604 (1994)] to compute light scattering by bispheres in fixed and random orientations extensively. For all our computations the index of refraction is fixed at a value 1.5 + 0.005i, which is close to the refractive index of mineral tropospheric aerosols and was used in previous extensive studies of light scattering by spheroids and Chebyshev particles. For monodisperse bispheres with touching components in a fixed orientation, electromagnetic interactions between the constituent spheres result in a considerably more complicated interference structure in the scattering patterns than that for single monodisperse spheres. However, this increased structure is largely washed out by orientational averaging and results in scattering patterns for randomly oriented bispheres that are close to those for single spheres with size equal to the size of the bisphere components. Unlike other nonspherical particles such as cubes and spheroids, randomly oriented bispheres do not exhibit pronounced enhancement of side scattering and reduction of backscattering and positive polarization at side-scattering angles. Thus the dominant feature of light scattering by randomly oriented bispheres is the single scattering from the component spheres, whereas the effects of cooperative scattering and concavity of the bisphere shape play a minor role. The only distinct manifestations of nonsphericity and cooperative scattering effects for randomly oriented bispheres are the departure of the ratio F-22/F-11 of the elements of the scattering matrix from unity, the inequality of the ratios F-33/F-11 and F-44/F-11, and nonzero linear and circular backscattering depolarization ratios. Our computations for randomly oriented bispheres with separated wavelength-sized components show that the component spheres become essentially independent scatterers at as small a distance between their centers as 4 times their radii. C1 AUBURN UNIV, DEPT MECH ENGN, AUBURN, AL 36849 USA. RP NASA, GODDARD INST SPACE STUDIES, 2880 BROADWAY, NEW YORK, NY 10025 USA. RI Mackowski, Daniel/K-1917-2013; Mishchenko, Michael/D-4426-2012 NR 42 TC 97 Z9 101 U1 3 U2 7 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 JUL 20 PY 1995 VL 34 IS 21 BP 4589 EP 4599 PG 11 WC Optics SC Optics GA RL129 UT WOS:A1995RL12900049 PM 21052291 ER PT J AU BERSANELLI, M BENSADOUN, M DANESE, L DEAMICI, G KOGUT, A LEVIN, S LIMON, M MAINO, D SMOOT, GF WITEBSKY, C AF BERSANELLI, M BENSADOUN, M DANESE, L DEAMICI, G KOGUT, A LEVIN, S LIMON, M MAINO, D SMOOT, GF WITEBSKY, C TI EFFECTS OF ATMOSPHERIC EMISSION ON GROUND-BASED MICROWAVE BACKGROUND MEASUREMENTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATMOSPHERIC EFFECTS; COSMIC MICROWAVE BACKGROUND; EARTH ID RADIATION TEMPERATURE; SCALE MEASUREMENT; SOUTH-POLE; 7.5 GHZ; WAVELENGTH; FREQUENCY; SPECTRUM; RANGE AB We present an analysis of multifrequency measurements of atmospheric emission in the Rayleigh-jeans portion of the cosmic microwave background spectrum (1-90 GHz) taken since 1986 from White Mountain, CA, and from the South Pole. Correlations of simultaneous data at 10 and 90 GHz and accurate low-frequency measurements show good agreement with model predictions for both sites. Our data from the South Pole 1989 campaign combined with real-time measurements of the local atmospheric profiles provide accurate verification of the expected independent contributions of H2O and O-2 emission. We show that variations on the order of 10% of the oxygen emission (both resonant and nonresonant components) are present on timescales of hours to days, mainly due to the evolution of the atmospheric pressure profile. Oxygen emission fluctuations appear larger than previously expected and may have significant consequences for ground-based cosmic microwave background experiments. C1 UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. SCUOLA INT SUPER STUDI AVANZATI,I-34014 TRIESTE,ITALY. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP BERSANELLI, M (reprint author), CNR,IST FIS COSM,VIA BASSINI 15,I-20133 MILAN,ITALY. RI Kogut, Alan/D-6293-2012 NR 37 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 8 EP 16 DI 10.1086/175937 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900002 ER PT J AU TSAI, JC MATHEWS, WG AF TSAI, JC MATHEWS, WG TI INTERSTELLAR GRAINS IN ELLIPTIC GALAXIES - GRAIN EVOLUTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE COOLING FLOWS; DUST, EXTINCTION; GALAXIES, ELLIPTIC AND LENTICULAR, CD; INFRARED, GALAXIES ID X-RAY; INFRARED-EMISSION; HOT GAS; TEMPERATURE-FLUCTUATIONS; SIZE DISTRIBUTION; DUST; CLUSTERS; PHOTOMETRY; FLOWS AB We consider the lifecycle of dust introduced into the hot interstellar medium in isolated elliptical galaxies. Dust grains are ejected into galactic-scale cooling flows in large ellipticals by normal mass loss from evolving red giants. Newly introduced dust rapidly enters the hot interstellar plasma and is sputtered away by thermal collisions with ions during the slow migration toward the galactic center in the cooling flow. Before the grains are completely sputtered away, however, they emit prodigious amounts of infrared radiation which may contribute to the large far infrared luminosities observed in ellipticals. The infrared emission depends critically on the sputtering rate. Since our understanding of both the plasma and radiation environments in ellipticals is quite good, these galaxies provide an excellent venue for studying the physical processes of dust grains and perhaps also their composition and size distribution. In older to study the global properties of grains in ellipticals we construct a new series of King-type galactic models which are consistent with the fundamental plane, galactic mass to light ratios and other relevant observational correlations. We describe a new ''continuity'' procedure to construct simple time-dependent gasdynamic models for cooling flows. Although grains can flow a considerable distance from their radius of origin in the hot interstellar medium of some galaxies before being sputtered away, we show that the grain size distribution at every radius is accurately determined by assuming in situ sputtering of dust grains, completely ignoring advection. This occurs since the stellar density profile is so steep that the majority of grains at any galactic radius is produced locally. Although thermal sputtering destroys the grains, we show that the dominant source of grain heating is absorption of starlight; grain heating by collisions with energetic thermal electrons or X-ray absorption are negligible. Previous studies have claimed that the loss of thermal energy from a hot, dusty plasma is dominated by grain heating via electron-grain collisions and subsequent IR radiation. However, we show that when self-consistent grain sputtering is included the dust-to-gas ratio is reduced and radiative cooling. not electron grain interactions dominates plasma cooling, even for the most massive ellipticals. This conclusion is insensitive to the grain size distribution assumed for the stellar ejecta. C1 UNIV CALIF SANTA CRUZ,UNIV CALIF OBSERV,LICK OBSERV,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064. UNIV TORONTO,MCLENNAN LABS,CANADIAN INST THEORET ASTROPHYS,TORONTO,ON M5S 1A7,CANADA. RP TSAI, JC (reprint author), NASA,AMES RES CTR,MAIL STOP 345-3,MOFFETT FIELD,CA 94035, USA. NR 54 TC 42 Z9 43 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 84 EP 97 DI 10.1086/175943 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900008 ER PT J AU HECKMAN, TM DAHLEM, M LEHNERT, MD FABBIANO, G GILMORE, D WALLER, WH AF HECKMAN, TM DAHLEM, M LEHNERT, MD FABBIANO, G GILMORE, D WALLER, WH TI AN X-RAY AND OPTICAL STUDY OF THE DWARF GALAXY NGC-1569 - EVIDENCE FOR A STARBURST-DRIVEN OUTFLOW SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, HALOS; GALAXIES, INDIVIDUAL (NGC 1569); GALAXIES, KINEMATICS AND DYNAMICS; GALAXIES, STARBURST; X-RAYS, GALAXIES ID ENHANCED GALACTIC WINDS; LOW-MASS GALAXIES; IRREGULAR GALAXIES; INTERSTELLAR-MEDIUM; STELLAR POPULATIONS; ELLIPTICAL GALAXIES; STAR FORMATION; VIRGO CLUSTER; EVOLUTION; NGC-1569 AB Supernova-driven outflows produced by intense bursts of star formation can drastically affect the structure and subsequent evolution of dwarf galaxies. Extensive mass loss from such systems may also provide an important source of chemical enrichment for the intergalactic medium. Despite the potential importance of these outflows, there is a very limited amount of direct observational evidence for their existence. One of the clearest signatures of a starburst-driven outflow is the X-ray emission from the hot gas that drives the outflow. We have therefore undertaken an X-ray imaging and optical spectroscopic investigation of the nearest and best-studied starbursting dwarf galaxy NGC 1569 using the HRI on ROSAT and the Ritchey-Chretien spectrograph on the KPNO 4 m telescope, respectively. We find that at least half the keV X-ray emission of NGC 1569 is associated with a diffuse halo that is some 3.'8 x 2.'2 similar to 2.4 x 1.5 kpc in size. Kiloparsec-scale ''spurs'' of diffuse X-ray emission extend outward along or near the optical minor axis of the galaxy. These diffuse X-ray spurs are morphologically associated with the well-known system of H alpha filaments. Previous kinematic studies have suggested that the H alpha filament system is a bipolar outflow. Our new optical spectroscopic data show that the H alpha emission comprises two kinematically distinct components: a quiescent system about 1 kpc in size responsible for about 75% of the H alpha emission and a fainter and more complex system over 2 kpc in size with radial velocities of as much as +/-200 km s(-1) relative to v(sys). The latter appears to define expanding hollow structures consisting of several kiloparsec-scale ''superbubbles.'' The dynamical age of the high-velocity system (similar to 10(7) yr) is similar to various estimates of the age of the starburst. We also see very broad wings (full width at zero intensity of 1400-2300 km s(-1)) on the H alpha emission-line profile at the location of super starcluster A, suggestive of recent supernova activity there. We argue that the starburst in NGC 1569 is driving an outflow of the interstellar medium on a global scale. Our simple models suggest that the X-ray emission is too bright to come primarily from the hot tenuous supernova-heated gas in the interior of a superbubble, unless this gas is evaporating or ablating cool dense material. This latter material may be the outer shell of the superbubble or interstellar clouds that have been engulfed by the superbubble. The high-velocity H alpha filaments probably correspond to the shocked and accelerated ambient material in the superbubble's outer walls, while the low-velocity material may be massive photoionized clouds in the starbursting galactic disk. The observed expansion speeds probably exceed the galactic escape velocity. It seems likely that the expanding material will ultimately ''blow out'' of the interstellar medium, and in so doing may allow most of the metals created by the starburst to escape from the galaxy. It is less clear whether the outflow will lead to the ejection of most or ah of this galaxy's interstellar medium, though it appears at least energetically feasible. We briefly discuss the significance of these results for ideas about the evolution of dwarf galaxies. C1 LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94551 USA. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, HUGHES STX CORP, GREENBELT, MD 20771 USA. RP HECKMAN, TM (reprint author), JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. NR 100 TC 129 Z9 129 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 JUL 20 PY 1995 VL 448 IS 1 BP 98 EP 118 DI 10.1086/175944 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900009 ER PT J AU BUTNER, HM LADA, EA LOREN, RB AF BUTNER, HM LADA, EA LOREN, RB TI PHYSICAL-PROPERTIES OF DENSE CORES - DCO+ OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, KINEMATICS AND DYNAMICS; ISM, MOLECULES; RADIO LINES, ISM ID L134N MOLECULAR CORE; DARK CLOUDS; INTERSTELLAR CLOUDS; DEUTERIUM FRACTIONATION; ROTATIONAL-EXCITATION; NH3 OBSERVATIONS; HCO+; CS; TEMPERATURE; EXTINCTION AB We conducted a survey for (CO)-O-18, DCO+, and (HCO+)-C-13 J = 1 --> 0 emission in a sample of low-mass cores previously surveyed in CS, NH3 and C3H2. The DCO+ and (HCO+)-C-13 observations were used to test deuterium fractionation chemistry models for TMC-1 type clouds. The [DCO+/HCO+] fractionation ratio (0.045 +/- 0.014) was found to be in excellent agreement with current models. In addition, we did a multiple transition study of DCO+ emission which revealed the presence of denser gas (n proportional to 10(5) cm(-3)) than most previous molecular line studies of these cores had found. The observations also suggested that those cores which are associated with young stars have slightly higher densities on average than those cores which have no associated star. We also found that DCO+ line-widths for the cores studied are significantly broader than the previously observed NH, line widths. The DCO+ line width broadening does not appear to be entirely an opacity effect. Instead, the broader line width suggests the presence inside the core of a dense supersonic gas component not traced by NH3. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742. RP BUTNER, HM (reprint author), CARNEGIE INST WASHINGTON,DEPT TERR MAGNETISM,5241 BROAD BRANCH RD NW,WASHINGTON,DC 20015, USA. OI Butner, Harold/0000-0003-4899-2064 NR 45 TC 79 Z9 79 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 207 EP 225 DI 10.1086/175953 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900018 ER PT J AU CHARNLEY, SB KRESS, ME TIELENS, AGGM MILLAR, TJ AF CHARNLEY, SB KRESS, ME TIELENS, AGGM MILLAR, TJ TI INTERSTELLAR ALCOHOLS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, ABUNDANCES; ISM, CLOUDS; ISM, MOLECULES; MOLECULAR PROCESSES ID MOLECULAR CLOUDS; MICROWAVE-SPECTRUM; ORGANIC-MOLECULES; COMPACT RIDGE; DIPOLE-MOMENT; DENSE CLOUDS; DARK CLOUDS; ABUNDANCES; CHEMISTRY; COMPLEXITY AB We have investigated the gas-phase chemistry in dense cores where ice mantles containing ethanol and other alcohols have been evaporated. Model calculations show that methanol, ethanol propanol, and butanol drive a chemistry leading to the formation of several large ethers and esters. Of these molecules, methyl ethyl ether (CH3OC2H5) and diethyl ether [(C2H5)(2)O] attain the highest abundances and should be present in detectable quantities within cores rich in ethanol and methanol. Gas-phase reactions act to destroy evaporated ethanol and a low observed abundance of gas-phase C2H5OH does not rule out a high solid-phase abundance. Grain surface formation mechanisms and other possible gas-phase reactions driven by alcohols are discussed, as are observing strategies for the detection of these large interstellar molecules. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. UNIV MANCHESTER,INST SCI & TECHNOL,DEPT MATH,MANCHESTER M60 1QD,LANCS,ENGLAND. RENSSELAER POLYTECH INST,DEPT PHYS,TROY,NY 12180. RP CHARNLEY, SB (reprint author), UNIV CALIF BERKELEY,DEPT ASTRON,601 CAMPBELL HALL,BERKELEY,CA 94720, USA. RI Charnley, Steven/C-9538-2012; OI Millar, Tom/0000-0001-5178-3656 NR 51 TC 141 Z9 141 U1 0 U2 17 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 232 EP 239 DI 10.1086/175955 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900020 ER PT J AU HESTER, JJ SCOWEN, PA SANKRIT, R BURROWS, CJ GALLAGHER, JS HOLTZMAN, JA WATSON, A TRAUGER, JT BALLESTER, GE CASERTANO, S CLARKE, JT CRISP, D EVANS, RW GRIFFITHS, RE HOESSEL, JG KRIST, J LYNDS, R MOULD, JR ONEIL, EJ STAPELFELDT, KR WESTPHAL, JA AF HESTER, JJ SCOWEN, PA SANKRIT, R BURROWS, CJ GALLAGHER, JS HOLTZMAN, JA WATSON, A TRAUGER, JT BALLESTER, GE CASERTANO, S CLARKE, JT CRISP, D EVANS, RW GRIFFITHS, RE HOESSEL, JG KRIST, J LYNDS, R MOULD, JR ONEIL, EJ STAPELFELDT, KR WESTPHAL, JA TI WFPC2 STUDIES OF THE CRAB-NEBULA .1. HST AND ROSAT IMAGING OF THE SYNCHROTRON NEBULA SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, INDIVIDUAL (CRAB NEBULA); ISM, JETS AND OUTFLOWS; ISM, STRUCTURE; X-RAYS, ISM ID PULSAR WIND BUBBLE; MAGNETOHYDRODYNAMIC MODEL; OPTICAL IMAGERY; MAGNETOSPHERES; ULTRAVIOLET; RESOLUTION; BAYS AB We present images of the Crab synchrotron nebula obtained with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. These data are compared with ROSAT HRI images, and with 0.''5 resolution Canada-France-Hawaii Telescope (CFHT) images previously published by van den Bergh and Pritchet (1989). These data strengthen the emerging picture of the Crab as a cylindrically symmetrical object with an axis running southeast to northwest, and inclined by similar to 20 degrees-30 degrees with respect to the plane of the sky, Identification of structure very near to the pulsar which shares this symmetry helps to better establish the link between the symmetry axis of the nebula and the spin axis of the pulsar. We report the discovery of a bright knot of visible emission located 0.''65 to the southeast of the pulsar, along the axis of the system. This knot and a second knot 3.''8 from the pulsar appear to be present but not well resolved in the 1988 CFHT image, indicating that they are persistent structures. The inner knot is interpreted as a shock in the pulsar wind similar to 1500 AU above the pole of the pulsar, No corresponding knots are seen to the northwest of the pulsar, which may indicate that the characteristics of the wind from the two poles are not symmetrical. The closest of the ''wisps'' to the northwest of the pulsar appear to close into a ringlike ''halo'' encircling the axis of the nebula. The wisps are resolved with widths of similar to 0.''2. This allows calculation of their volumes and volume emissivities, and in turn their equipartition fields and pressures, Equipartition pressures calculated for the knots and wisps are typically 10 to as much as 80 times the equipartition pressure calculated for the nebula as a whole. The wisps show significant substructure which changed considerably between 1988 and 1994. Previous reports of relativistic motions of the wisps were probably due to changes in the unresolved substructure of these features. Comparison of the CFHT and WFPC2 images show remarkable changes in the inner nebula, but inferences about physical conditions based on this comparison are limited by the resolution of the CFHT data and the long 5 year baseline between the images. The structure of the nebula in 1994 may be inconsistent with the recent model by Gallant and Arons (1994). Very fine fibrous texture visible in the WFPC2 image follows the structure of the X-ray torus. A puzzling anticorrelation is seen between the X-ray and visible surface brightness through part of the torus. Long contiguous low contrast features with widths of similar to 1''-2'' are seen to run throughout the volume of the nebula. These features are seen to move outward through the nebula at velocities in excess of homologous expansion. These features trace the magnetic structure of the nebula; they are probably due to differences in emissivity accompanying varying degrees of departure from equipartition at roughly constant total pressure. Visible fibers ''drape over'' and appear to expand away from an X-ray counterjet to the northwest of the pulsar, supporting the interpretation of the counterjet as a directed dow of energy along the symmetry axis of the nebula Other associations are also seen between X-ray and visible structures, including X-ray emission surrounding the east and west bays. An association is proposed between the observed structure of the nebula and different latitude zones found in models of winds from partially oblique rotators. We concur with previous suggestions that the X-ray torus and the sharp visible fibers associated with it mark a shock at r(s) similar to 1.2 x 10(18) cm in an equatorial striped magnetic wind. The halo and anvil arise at a distance of similar to 1.4 x 10(17) cm from the pulsar in a helically polarized wind at latitudes greater than about 35 degrees. Well collimated polar jets may be responsible for the knots to the southeast of the pulsar and for the jet and counterjet seen at X-ray and visible wavelengths. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. LOWELL OBSERV,FLAGSTAFF,AZ 86001. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV MICHIGAN,DEPT ATMOSPHER & OCEAN SCI,ANN ARBOR,MI 48109. JOHNS HOPKINS UNIV,DEPT ASTRON,BALTIMORE,MD 21218. NATL OPT ASTRON OBSERV,KITT PEAK NATL OBSERV,TUCSON,AZ 85726. AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,WESTON,ACT 2611,AUSTRALIA. CALTECH,DEPT GEOL & PLANETARY SCI,PASADENA,CA 91125. RP HESTER, JJ (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,BOX 871504,TYLER MALL,TEMPE,AZ 85287, USA. RI Stapelfeldt, Karl/D-2721-2012; Clarke, John/C-8644-2013 NR 63 TC 205 Z9 205 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 240 EP & DI 10.1086/175956 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900021 ER PT J AU ULMER, MP MATZ, SM GRABELSKY, DA GROVE, JE STRICKMAN, MS MUCH, R BUSETTA, MC STRONG, A KUIPER, L THOMPSON, DJ BERTSCH, D FIERRO, JM NOLAN, PL AF ULMER, MP MATZ, SM GRABELSKY, DA GROVE, JE STRICKMAN, MS MUCH, R BUSETTA, MC STRONG, A KUIPER, L THOMPSON, DJ BERTSCH, D FIERRO, JM NOLAN, PL TI COMPTON GAMMA-RAY OBSERVATORY OBSERVATIONS OF THE CRAB PULSAR SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, OBSERVATIONS; PULSARS, INDIVIDUAL (CRAB PULSAR) ID RAPIDLY SPINNING PULSARS; INSTRUMENT DESCRIPTION; ENERGETIC RADIATION; TELESCOPE; NEBULA AB We present Crab pulsar light curves and spectra over the similar to 50 keV to 10 GeV range from Compton Gamma-Ray Observatory observations made during MJD 48,373-48,406 (1991 April 27-1991 May 30 except for COMPTEL which started observations on April 28). The overall pulse phase-averaged spectrum is not well fitted by a single power law, but a broken power law does fit well, of the form F = A(E/E(B))((-alpha 1)); A(E/E(R))(-alpha 2) photons cm(-2) s(-1) MeV(-1) fits well (chi(min)(2), = 16, 26 degrees of freedom [dof]), where alpha(1) is the spectral index for E less than or equal to E(B) and alpha(2) for E > E(B). For the normalization values to the spectra quoted here, we report phase-averaged intensities, and we applied an estimate to the uncertainty of the absolute calibration of 10%. The best-fit values for the parameters with 68% uncertainties are A = 0.064 +/- 0.006, E(B) = 0.12 +/- 0.03 MeV, alpha(1) = 1.71(+0.15)(-0.19), and alpha(2) = 2.21 +/- 0.02. The outer gap model (with gap parameter equal to 0.38, and a normalization factor of 1.08) provided to us by Ho describes the data with an accuracy of better than 20%, but the formal chi(min)(2), is too high with a value of 68 for 28 dof. We derive a statistically equivalent result for the broken power law when we include lower energy data from the OSO 8 satellite. A broken power-law fit to the phase-resolved spectra (peak 1, the bridge, and peak 2) resulted in the following: for peak 1, A = 0.026 +/- 0.003, E(B) = 0.098 +/- 0.02 MeV, alpha(1) = 1.77(-0.25)(+0.188), alpha(2) = 2.09 +/- 0.01, chi(min)(2) = 45, 26 dof; for the bridge, A = 0.001 +/- 0.0001, E(B) = 0.45(-0.15)(+0.85) MeV, alpha(1) = 1.75 +/- 0.12, alpha(2) = 2.53(-0.12)(+0.10) chi(min)(2), d, = 16, 23 dof; and for peak 2, A = 0.02 +/- 0.002, E(B) = 0.13(-0.012)(+0.020) MeV, alpha(1) = 1.71 +/- 0.09, alpha 2 = 2.25 +/- 0.02, chi(min)(2) 21, 26 dof. For peak 1 only, the fit is greatly improved by using an outer gap model. The resultant values are a gap parameter of 0.450 +/- 0.003 with a normalization of 0.22 +/- 0.02, chi(min)(2). = 32, 28 dof. The separation of the pulse peaks is difficult to quantify objectively because the peaks are not symmetrical. When we use the maximum intensity values of each peak to determine the centroids, we find an energy-independent phase difference of 0.405 +/- 0.006 for the CGRO data (50 keV to 10 GeV) and 0.402 +/- 0.002 when other data were included covering the range from 0.5 to 300 keV. The energy-independent value of the phase of peak 1 relative to the radio is -0.003 +/- 0.012, where the uncertainty includes the absolute timing uncertainty. When the pulse shapes are characterized by asymmetric Lorentzian shapes, within the statistical uncertainty of the fits the widths of the peaks in the similar to 100 keV light curve are consistent within a factor of about 1.25 with the widths of the peaks in the similar to 100 MeV light curve. We discuss these results within the context of a bulk relativistic motion beaming model. C1 USN, RES LAB, EO HULBURT CTR SPACE RES, WASHINGTON, DC 20375 USA. ESTEC, DIV ASTROPHYS, 2200 AG NOORDWIJK, NETHERLANDS. MAX PLANCK INST EXTRATERR PHYS, D-85740 GARCHING, GERMANY. SRON, 3584 CA UTRECHT, NETHERLANDS. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. STANFORD UNIV, WW HANSEN EXPTL PHYS LAB, STANFORD, CA 94305 USA. STANFORD UNIV, DEPT PHYS, STANFORD, CA 94305 USA. RP ULMER, MP (reprint author), NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. RI Nolan, Patrick/A-5582-2009; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 38 TC 24 Z9 24 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 JUL 20 PY 1995 VL 448 IS 1 BP 356 EP 364 DI 10.1086/175966 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900031 ER PT J AU BOYD, PT VANCITTERS, GW DOLAN, JF WOLINSKI, KG PERCIVAL, JW BLESS, RC ELLIOT, JL NELSON, MJ TAYLOR, MJ AF BOYD, PT VANCITTERS, GW DOLAN, JF WOLINSKI, KG PERCIVAL, JW BLESS, RC ELLIOT, JL NELSON, MJ TAYLOR, MJ TI HIGH-SPEED PHOTOMETER OBSERVATIONS OF THE LMC-PULSAR B0540-69 SO ASTROPHYSICAL JOURNAL LA English DT Article DE PULSARS, INDIVIDUAL (B0540-69); ULTRAVIOLET, STARS ID LARGE MAGELLANIC CLOUD; 50 MILLISECOND PULSAR; PSR 0540-69; CRAB PULSAR; PSR-0540-69; ULTRAVIOLET AB The High-Speed Photometer (HSP) on board the Hubble Space Telescope (HST) observed the 50 ms pulsar B0540-69 in the Large Magellanic Cloud on 1993 August 26 for 1 hr in a passband extending from 1600 Angstrom to 7000 Angstrom. The pulse profile resembles both that in the optical region alone and in the X-ray region. The pulsed fraction in the UV-plus-visible passband is 0.16 +/- 0.02, similar to that measured in the X-ray region. The pulsar frequency on MJD 49225.2557 (start time of the observation) was 19.83448 +/- 0.00002 Hz. When we combine our observed frequency with other published X-ray and optical observations and assume no discontinuities (glitches) in the spin-down rate since 1979, we derive a braking index n = 2.28 +/- 0.02. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NATL SCI FDN,DIV ASTRON SCI,ARLINGTON,VA 22230. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. UNIV WISCONSIN,SPACE ASTRON LAB,MADISON,WI 53706. MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. LORAS COLL,DEPT PHYS & ENGN,DUBUQUE,IA 52004. RP BOYD, PT (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Boyd, Patricia/D-3274-2012 NR 27 TC 41 Z9 41 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1995 VL 448 IS 1 BP 365 EP 368 DI 10.1086/175967 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ489 UT WOS:A1995RJ48900032 ER PT J AU BELWARD, A HOLLIFIELD, A JAMES, M AF BELWARD, A HOLLIFIELD, A JAMES, M TI THE POTENTIAL OF THE NASA GAC PATHFINDER PRODUCT FOR THE CREATION OF GLOBAL THEMATIC DATA SETS - THE CASE OF BIOMASS BURNING PATTERNS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Note AB NASA's Advanced Very High Resolution Radiometer Global Area Coverage (GAG) Pathfinder data are compared with the European Commission's GAC data set, as a step towards validation of this new NASA product. Results show that the NASA data have considerable potential for describing global land surface processes, such as biomass burning patterns. C1 SERCO EUROPE LTD,SOUTHALL UB2 5NJ,MIDDX,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,CTR GLOBAL CHANGE DATA,GREENBELT,MD 20771. RP BELWARD, A (reprint author), COMMISS EUROPEAN COMMUNITIES,JOINT RES CTR,INST REMOTE SENSING APPLICAT,I-21020 ISPRA,ITALY. OI Hollifield, Ann/0000-0002-6800-9947 NR 6 TC 4 Z9 4 U1 0 U2 1 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUL 20 PY 1995 VL 16 IS 11 BP 2089 EP 2097 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA RP225 UT WOS:A1995RP22500013 ER PT J AU KOSTER, RD SUAREZ, MJ AF KOSTER, RD SUAREZ, MJ TI RELATIVE CONTRIBUTIONS OF LAND AND OCEAN PROCESSES TO PRECIPITATION VARIABILITY SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEA-SURFACE TEMPERATURE; NORTH-AMERICAN DROUGHT; UNITED-STATES; SOIL-MOISTURE; CLIMATE; CIRCULATION; RAINFALL; BRAZIL; MODEL; WATER AB A series of general circulation model simulations are used to quantify the relative contributions of land surface and ocean variability to variability in precipitation. The simulations show that land surface processes contribute significant to the variance of annual precipitation over continents. In contrast, ocean processes acting alone have a much smaller effect, particularly in midlatitudes. The precipitation variability reflects local evaporation variability and associated hydrological persistence, and it responds most strongly to the land surface during summer, when moist convection dominates. C1 NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, CLIMATE & RADIAT BRANCH, GREENBELT, MD 20771 USA. RP KOSTER, RD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HYDOSPHER PROC LAB, HYDROL SCI BRANCH, CODE 974, GREENBELT, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 39 TC 94 Z9 96 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 13775 EP 13790 DI 10.1029/95JD00176 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000003 ER PT J AU SHAH, KP RIND, D AF SHAH, KP RIND, D TI USE OF MICROWAVE BRIGHTNESS TEMPERATURES WITH A GENERAL-CIRCULATION MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MILLIMETER-WAVE-PROPAGATION; RADIOSONDE VALIDATION; SOUNDING UNIT; WATER-VAPOR; ANOMALIES; CLIMATE; AIR; PRECISION; TRENDS; MSU AB Brightness temperature maps from global monthly mean general circulation. model (GCM) atmospheric and surface fields are calculated with a new microwave radiative transfer postprocessor. This microwave radiative transfer model uses fields from the 4 degrees by 5 degrees Goddard Institute for Space Studies (GISS) GCM Model II and subsequent developmental versions of the GCM. The absolute brightness temperature maps from the microwave radiative transfer model are shown to be more accurate than maps from temperature weighting functions due to the inclusion of local surface emission and local radiative transfer effects. This permits direct comparison of calculated brightness temperatures to observed brightness temperatures measured by the microwave sounding unit (MSU) channels. Microwave maps are calculated for the January and July Geophysical Fluid Dynamics Laboratory (GFDL) radiosonde upper air and surface climatology and compared to the MSU climatology. This work tests the microwave radiative transfer model and comments on two disparate tropospheric climatologies used for trend analysis and GCM validation. The microwave comparison generally finds good agreement between the MSU channel 2 and the radiosonde climatologies. January brightness temperature differences of a few degrees come from spatial coverage gaps and land biasing in the radiosonde climatology, echoing results in previous comparison studies. The July microwave comparison finds unexpected warmth brightness temperatures from the radiosonde climatology over land masses. This July warmth may be related to diurnal sampling differences and to recent study by other researchers into radiosonde time series' sensitivity to instrumentation and to solar heating of the radiosonde. Comparison of calculated GCM microwave maps to observed monthly mean MSU maps aids development of the GISS GCM. MSU channel 2R and channel 2 are used to evaluate the impacts of GCM developments near the ocean surface and the midtroposphere, respectively. These microwave channels show large sensitivity to the planetary boundary layer scheme. MSU channel 4 confirms improvements in the lower stratosphere with addition of a parameterized gravity wave drag beneath the GCM's rigid model top. Overall, the MSU climatology with its global coverage, several broad vertical samplings, and horizontal resolution comparable to GCM grid cells complements more traditional observations used to validate general circulation models. C1 NASA, GODDARD INST SPACE STUDIES, GODDARD SPACE FLIGHT CTR, NEW YORK, NY 10025 USA. RP SHAH, KP (reprint author), NASA, GODDARD INST SPACE STUDIES, COLUMBIA UNIV, CTR CLIMATE SYST RES, 2800 BROADWAY, NEW YORK, NY 10025 USA. NR 58 TC 21 Z9 21 U1 0 U2 0 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 JUL 20 PY 1995 VL 100 IS D7 BP 13841 EP 13874 DI 10.1029/95JD00772 PG 34 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000007 ER PT J AU KENT, GS WANG, PH MCCORMICK, MP SKEENS, KM AF KENT, GS WANG, PH MCCORMICK, MP SKEENS, KM TI MULTIYEAR STRATOSPHERIC AEROSOL AND GAS EXPERIMENT-II MEASUREMENTS OF UPPER-TROPOSPHERIC AEROSOL CHARACTERISTICS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EQUATORIAL NORTH-ATLANTIC; EL-CHICHON; SIZE DISTRIBUTION; VERTICAL PROFILES; SAGE; SATELLITE; PINATUBO; CLOUD; VALIDATION; TRANSPORT AB Measurements of aerosol extinction at wavelengths of 0.525 and 1.02 mu m, made by the Stratospheric Aerosol and Gas Experiment (SAGE) II solar occultation satellite experiment, have been used to Study the global-scale characteristics of the upper tropospheric aerosol. Extinction measurements, in which only aerosols occurred along the optical path, have been separated from those that included high-altitude cloud by examining the wavelength variation of the extinction. Data for the time period October 1984 to May 1991 show that the two main influences on the upper tropospheric aerosol were seasonal lifting of material from below and downward transfer of volcanic aerosol from the stratosphere. Maximum lifting of surface material occurs in local spring in both hemispheres and is observed at all latitudes between 20 degrees N and 80 degrees N and 20 degrees S and 60 degrees S; the data also show a strong hemispheric asymmetry with more aerosol in the northern hemisphere. Downward transfer of volcanic aerosol is particularly observed poleward of 40 degrees latitude; where a substantial enhancement of material occurs down to altitudes 2-3 km below the tropopause. By comparing tropospheric aerosol concentrations at different times during the period of observation, it has been possible to differentiate the effects of volcanic aerosols from those of the background, or baseline, aerosols. A simple model, based on the ratio of the extinctions at the two measurement wavelengths, has bean used to calculate the aerosol mass density and effective radius. It was found that in 1984-1985, approximately 15% of the Volcanic aerosol still present: from the eruption of El Chichon in 1982, resided in the upper troposphere. Particle sizes for the volcanic aerosol in the lower stratosphere and upper troposphere were of the order of 0.5 mu m, while those for the baseline aerosol were about 0.15 mu m. Slightly larger aerosol sizes, of the order of 0.25 mu m, were observed at altitudes 6-8 km during the springtime enhancements. The low-latitude aerosol enhancements in both hemispheres appear to have the characteristics of material derived from arid surface regions, while the higher-latitude aerosol in the northern hemisphere appears more likely to be derived from anthropogenic sources. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. RP KENT, GS (reprint author), SCI & TECHNOL CORP, 101 RES DR, POB 7390, HAMPTON, VA 23666 USA. NR 70 TC 47 Z9 49 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 13875 EP 13899 DI 10.1029/95JD00017 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000008 ER PT J AU LUO, M CICERONE, RJ RUSSELL, JM AF LUO, M CICERONE, RJ RUSSELL, JM TI ANALYSIS OF HALOGEN OCCULTATION EXPERIMENT HF VERSUS CH4 CORRELATION PLOTS - CHEMISTRY AND TRANSPORT IMPLICATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRACE CONSTITUENTS; N2O; MODEL AB The relationship between stratospheric CH4 and Hydrogen Fluoride (HF) observed simultaneously by the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) has been examined globally. The meridional structures of the two long-lived species for the equinox and solstice seasons are found to be very similar. Their surfaces of constant mixing ratio, however, are found to not quite coincide. The isopleth of CH4 graphed as pressure versus latitude shows a steeper slope than that of HF. This feature can be clearly seen from the scatterplots of CH4 versus HF for a sequence of latitude regions. In general, CH4-HF correlation plots are characterized by tightly fitted curves for different latitude bands; curves for the tropics and high latitudes define the envelope for the correlations. The NCAR two-dimensional model simulation of CH4 and HF agrees well with HALOE observations, and it shows that the altitude-latitude dependences of CH4 removal and HF production rates play an important role in determining global CH4-HF correlations. It is found that the CH4-HF correlation inside the Antarctic vortex is nearly linear and is shifted from that of outside the vortex and from that of polar late-summer before the formation of the vortex. HALOE observations of CH4 and HF indicate that the two species are not in states of perfect ''slope equilibrium'' or ''gradient equilibrium'' globally. The obvious shift of HF values on CH4 surfaces or vice versa is usually found across dynamical barriers. There is no universal relationship between CH4 and HF. The HF mixing ratios are observed to change up to 20-35% for a given CH4 from different dynamically isolated regions such as the polar vortex, midlatitudes, and the tropics, and the same magnitudes of change in CH4 could also be found for a fixed HF. Therefore one must be cautious in the usage of correlation-inferring methods for any pair of tracers in place of unavailable measurements or for evaluating chemical disturbances. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. RP LUO, M (reprint author), UNIV CALIF IRVINE, DEPT EARTH SYST SCI, IRVINE, CA 92717 USA. NR 25 TC 16 Z9 16 U1 0 U2 0 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 JUL 20 PY 1995 VL 100 IS D7 BP 13927 EP 13937 DI 10.1029/95JD00621 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000011 ER PT J AU MANNEY, GL FROIDEVAUX, L WATERS, JW ZUREK, RW GILLE, JC KUMER, JB MERGENTHALER, JL ROCHE, AE ONEILL, A SWINBANK, R AF MANNEY, GL FROIDEVAUX, L WATERS, JW ZUREK, RW GILLE, JC KUMER, JB MERGENTHALER, JL ROCHE, AE ONEILL, A SWINBANK, R TI FORMATION OF LOW-OZONE POCKETS IN THE MIDDLE STRATOSPHERIC ANTICYCLONE DURING WINTER SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR VORTEX; SOUTHERN; ATMOSPHERE; CLAES; UARS; MLS AB Microwave limb sounder observations of midstratospheric ozone during stratospheric warmings show tongues of high ozone drawn up from low latitudes into the developing anticyclone. Several days later, an isolated pocket of low ozone mixing ratios appears, centered in the anticyclone, and extending in the vertical from approximate to 15 to 5 hPa, with higher mixing ratios both above and below. These low ozone mixing ratios during northern hemisphere warmings are comparable to values well inside the vortex and are approximate to 3 parts per million by volume lower than typical midlatitude extra-vortex mixing ratios. This type of feature is seen whenever the anticyclone is strong and persistent, including during relatively strong minor warmings in the southern hemisphere. Three-dimensional back trajectory calculations indicate that the air in the region of the low-ozone pockets originates at higher altitudes and low latitudes, where ozone mixing ratios are much higher. The air parcels studied here are typically confined together for 1 to 3 weeks before the lowest ozone mixing ratios are observed. The trajectory calculations and comparisons with passive tracer data confirm that the observed low-ozone regions in the midstratosphere could not result solely from transport processes. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. LOCKHEED PALO ALTO RES LABS, PALO ALTO, CA 94304 USA. UNIV READING, CTR GLOBAL ATMOSPHER MODDELLING, READING RG6 2AU, BERKS, ENGLAND. METEOROL OFF, DIV CR, BRACKNELL RG12 2SZ, BERKS, ENGLAND. RP MANNEY, GL (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MAIL STOP 183-701, PASADENA, CA 91109 USA. NR 20 TC 34 Z9 35 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 13939 EP 13950 DI 10.1029/95JD00372 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000012 ER PT J AU ECKMAN, RS GROSE, WL TURNER, RE BLACKSHEAR, WT RUSSELL, JM AF ECKMAN, RS GROSE, WL TURNER, RE BLACKSHEAR, WT RUSSELL, JM TI STRATOSPHERIC TRACE CONSTITUENTS SIMULATED BY A 3-DIMENSIONAL GENERAL-CIRCULATION MODEL - COMPARISON WITH UARS DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFATE AEROSOLS; OZONE DEPLETION; ODD NITROGEN; CHEMISTRY; WINTER; ATMOSPHERE; HOLE; CLO AB Constituent distributions are presented from the NASA Langley three-dimensional general circulation model, incorporating a comprehensive chemistry scheme. A 7-year, gas phase model simulation was performed to investigate long-term model stability, In addition, a 1-year simulation was made using parameterized polar heterogeneous processes and reactions occurring on sulfate aerosols. The results of these simulations are compared with species climatologies and with satellite data sets in order to characterize and evaluate model performance and identify aspects of the chemical scheme requiring improvement. The agreement between the modeled seasonal variation of total ozone and the measurement climatologies is satisfactory but with some differences with respect to the depth and persistence of the southern springtime ozone depletion. Comparisons of the model simulation with observations made from UARS were performed. There is good accord between the microwave limb sounder observations of ozone and the model. Areas of agreement and disagreement are revealed between the model and the cryogenic array etalon spectrometer measurements of HNO3 and ClONO2, suggesting the need for a more detailed representation of sulfate aerosol processes in the model. The comparison between the modeled and the measured partitioning of odd chlorine species is improved in the upper stratosphere by the inclusion of an additional pathway to HCl from the reaction of ClO + OH. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. LOCKHEED PALO ALTO RES LABS, PALO ALTO, CA 94304 USA. RP ECKMAN, RS (reprint author), NASA, LANGLEY RES CTR, MAIL STOP 401B, HAMPTON, VA 23681 USA. NR 50 TC 36 Z9 36 U1 0 U2 0 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 JUL 20 PY 1995 VL 100 IS D7 BP 13951 EP 13966 DI 10.1029/95JD01278 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000013 ER PT J AU DOUGLASS, AR SCHOEBERL, MR STOLARSKI, RS WATERS, JW RUSSELL, JM ROCHE, AE MASSIE, ST AF DOUGLASS, AR SCHOEBERL, MR STOLARSKI, RS WATERS, JW RUSSELL, JM ROCHE, AE MASSIE, ST TI INTERHEMISPHERIC DIFFERENCES IN SPRINGTIME PRODUCTION OF HCL AND CLONO2 IN THE POLAR VORTICES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERE RESEARCH SATELLITE; MICROWAVE LIMB SOUNDER; ANTARCTIC OZONE; STRATOSPHERE; EVOLUTION; DEPLETION; CHLORINE; VORTEX; CLAES; CIO AB UARS observations of O-3 and ClO (Microwave Limb Sounder), ClONO2 and HNO3 (Cryogenic Array Etalon Spectrometer), NO, NO2, and HCl (Halogen Occultation Experiment), and model calculations are used to produce an exposition of the different processes through which the reservoir gases ClONO2 and HCl are reformed and the end of the polar winter. Comparison of the observations within the polar vortices shows that HCl increases more rapidly in the Antarctic vortex in spring than in the Arctic vortex. Model analysis shows that this occurs because the O-3 concentrations in the southern vortex fall well below those in the northern vortex. The Cl/ClO fraction calculated for the southern hemisphere is therefore up to 30 times higher, leading to rapid HCl formation by Cl + CH4. The concentrations of NO observed by HALOE are substantially lower for the northern hemisphere than for the southern hemisphere, even for similar values of the concentration of HNO3 and the production of NOX from HNO3 through photolysis and reaction with OH. This is consistent with the dependence of the NO/NOX ratio on the O-3 concentration, i.e., the daytime production rate of NO2 via NO + O-3 is reduced, leading to higher NO in the southern hemisphere. This higher concentration of NO also contributes to the rapid HCl increase as Cl production from ClO + NO is enhanced. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. LOCKHEED PALO ALTO RES LABS, PALO ALTO, CA 94303 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP DOUGLASS, AR (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHER CHEM & DYNAM BRANCH, GREENBELT, MD 20771 USA. RI Douglass, Anne/D-4655-2012; Stolarski, Richard/B-8499-2013 OI Stolarski, Richard/0000-0001-8722-4012 NR 29 TC 96 Z9 96 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 13967 EP 13978 DI 10.1029/95JD00698 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000014 ER PT J AU RINSLAND, CP GUNSON, MR ABRAMS, MC LOWES, LL ZANDER, R MAHIEU, E GOLDMAN, A IRION, FW AF RINSLAND, CP GUNSON, MR ABRAMS, MC LOWES, LL ZANDER, R MAHIEU, E GOLDMAN, A IRION, FW TI APRIL 1993 ARCTIC PROFILES OF STRATOSPHERIC HCL, CLONO2, AND CCL2F2 FROM ATMOSPHERIC TRACE MOLECULE SPECTROSCOPY ATLAS 2 INFRARED SOLAR OCCULTATION SPECTRA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WINTER STRATOSPHERE; NITRIC-ACID; SPACELAB-3; CHLORINE; GASES; OZONE AB Partitioning among the major components of the stratospheric odd chlorine family inside and outside of the remanent Arctic vortex has been studied on the basis of infrared solar occultation measurements obtained by the atmospheric trace molecule spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS 2 shuttle mission (April 8-17, 1993). Profiles of hydrogen chloride (HCl) and simultaneous profiles of chlorine nitrate (ClONO2) and CFC-12 (CCl2F2) are reported for examples of in-vortex and out-of-vortex conditions. Increased ClONO2 volume-mixing ratios (VMRs) are measured in the vortex below 20 mbar (similar to 25 km altitude) with a peak ClONO2 VMR of 2.05 +/- 0.45 ppbv (10(-9) per volume) at 56 mbar (similar to 19 km altitude). The reported error correspond to la uncertainties. Simultaneous CCl2F2 and N2O measurements, combined with published empirical relations, indicate that only 0.34 +/- 0.15 ppbv, about 10% of total chlorine, was bound in organic species at the ClONO2 VMR peak in the vortex. A colocated vortex profile of HCl, referenced to simultaneous N2O VMR measurements, has been used to derive a HCl mixing ratio of 1.21 +/- 0.12 ppbv corresponding to the ClONO2 VMR peak. The internal consistency of the ATMOS measurements is demonstrated by the agreement between the total chlorine mixing ratio of 3.60 +/- 0.72 ppbv derived at the ClONO2 VMR peak in the vortex and HCl measurements of 3.37 +/- 0.37 and 3.76 +/- 0.41 ppbv at 0.56 mbar, where HCl is the only significant chlorine-bearing molecule. Outside the vortex the mixing ratio of HCl exceeds the mixing ratio of ClONO2 throughout the stratosphere. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV DENVER, DEPT PHYS, DENVER, CO 80208 USA. CALTECH, DEPT CHEM ENGN, PASADENA, CA 91125 USA. UNIV LIEGE, INST ASTROPHYS, B-4000 LIEGE, BELGIUM. RP RINSLAND, CP (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL STOP 401A, HAMPTON, VA 23681 USA. NR 38 TC 15 Z9 15 U1 0 U2 0 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 JUL 20 PY 1995 VL 100 IS D7 BP 14019 EP 14027 DI 10.1029/95JD01047 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000018 ER PT J AU TORRES, O HERMAN, JR BHARTIA, PK AHMAD, Z AF TORRES, O HERMAN, JR BHARTIA, PK AHMAD, Z TI PROPERTIES OF MOUNT-PINATUBO AEROSOLS AS DERIVED FROM NIMBUS-7 TOTAL OZONE MAPPING SPECTROMETER MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFURIC-ACID; CLOUDS AB The perturbations to the radiances measured by the Nimbus 7 total ozone mapping spectrometer (TOMS) during the 18 months after the eruption of Mount Pinatubo are used to derive weekly zonal mean values for the stratospheric aerosol optical thickness at 312.5 nm and zonal-mean values for the area-weighted or effective radius. The method uses the TOMS observations, on both sides of the orbital track, of the detailed structure in the backscattering region of the aerosol-scattering phase function. Spatial and temporal evolution of the aerosol optical thickness and effective radius is obtained for the tropical region (25 degrees N to 25 degrees S) during most of the period mid-July 1991 to December 1992. The largest derived value of optical thickness was 0.22 (+36%/-10%), obtained for the latitude zone from 5 degrees to 15 degrees S at the end of July 1991. By the end of 1992, tropical optical depths varied from 0.02 to 0.06 over the 25 degrees N to 25 degrees S geographical area. The main source of uncertainty in the derived optical depth is the altitude of the aerosol layer. The inferred time evolution of the effective radius clearly shows an increase in particle size. At the end of July 1991, effective radius values of about 0.5 mu m were derived, while in the fall of 1992, these values were between 0.7 and 1.4 mu m. Corrections and error estimates are obtained for the measured ozone amounts. The zonal average retrieved ozone amounts corrected for the presence of aerosols are within 1% of the uncorrected zonal averages. Individual scan angles can have ozone amount corrections of +/-3%, with a nadir view correction of 2%. C1 SCI & DATA SYST INC, SILVER SPRING, MD 20906 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. HUGHES STX CORP, LANHAM, MD USA. RI Torres, Omar/G-4929-2013; Bhartia, Pawan/A-4209-2016 OI Bhartia, Pawan/0000-0001-8307-9137 NR 34 TC 20 Z9 22 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 14043 EP 14055 DI 10.1029/95JD01224 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000020 ER PT J AU KRUEGER, AJ WALTER, LS BHARTIA, PK SCHNETZLER, CC KROTKOV, NA SPROD, I BLUTH, GJS AF KRUEGER, AJ WALTER, LS BHARTIA, PK SCHNETZLER, CC KROTKOV, NA SPROD, I BLUTH, GJS TI VOLCANIC SULFUR-DIOXIDE MEASUREMENTS FROM THE TOTAL OZONE MAPPING SPECTROMETER INSTRUMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BACKSCATTER ULTRAVIOLET; PINATUBO AEROSOLS; STRATOSPHERIC SO2; ERUPTIONS; CLOUDS; INDEX; TOMS; ASH AB The total ozone mapping spectrometer (TOMS), first flown on the Nimbus 7 satellite, has delivered an unanticipated set of unique information about volcanic plumes because of its contiguous spatial mapping and use of UV wavelengths. The accuracies of TOMS sulfur dioxide retrievals, volcanic plume masses, and eruption totals under low-latitude conditions are evaluated using radiative transfer simulations and error analysis. The retrieval algorithm is a simultaneous solution of the absorption optical depth equations including ozone and sulfur dioxide at the four shortest TOMS wavelengths and an empirical correction based on background condition residuals. The retrieval algorithm reproduces model stratospheric sulfur dioxide plume amounts within +/-10% over most central scan angles and moderate solar zenith angles if no aerosols or ash are present. The errors grow to 30% under large solar zenith angle conditions. Volcanic ash and sulfate aerosols in the plume in moderate optical depths (0.3) produce an overestimation of the sulfur dioxide by 15-25% depending on particle size and composition. Retrievals of tropospheric volcanic plumes are affected by the reflectivity of the underlying surface or clouds. The precision of individual TOMS SO2 soundings is limited by data quantization to +/-6 Dobson units. The accuracy is independent of most instrument calibration errors but depends linearly on relative SO2 absorption cross-section errors at the TOMS wavelengths. Volcanic plume mass estimates are dependent on correction of background offsets integrated over the plume area. The errors vary with plume mass and area, thus are highly individual. In general, they are least for moderate size, compact plumes. Estimates of the total mass of explosively erupted sulfur dioxide depend on extrapolation of a series of daily plume masses backward to the time of the eruption. Errors of 15-30% are ndt unusual. Effusive eruption total mass estimates are more uncertain due to difficulties in separating new from old sulfur dioxide in daily observations. C1 MICHIGAN TECHNOL UNIV, DEPT GEOL ENGN & SCI, HOUGHTON, MI 49931 USA. NASA, GODDARD SPACE FLIGHT CTR, USRA, VISITING SCIENTIST PROGRAM, GREENBELT, MD 20771 USA. UNIV MARYLAND, DEPT GEOG, COLLEGE PK, MD 20742 USA. HUGHES STX CORP, LANHAM, MD 20706 USA. RP KRUEGER, AJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, EARTH SCI DIRECTORATE, GREENBELT, MD 20771 USA. RI Krotkov, Nickolay/E-1541-2012 OI Krotkov, Nickolay/0000-0001-6170-6750 NR 35 TC 163 Z9 172 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 14057 EP 14076 DI 10.1029/95JD01222 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000021 ER PT J AU STONE, EM STANFORD, JL ZIEMKE, JR ALLEN, DR TAYLOR, FW RODGERS, CD LAWRENCE, BN FISHBEIN, EF ELSON, LS WATERS, JW AF STONE, EM STANFORD, JL ZIEMKE, JR ALLEN, DR TAYLOR, FW RODGERS, CD LAWRENCE, BN FISHBEIN, EF ELSON, LS WATERS, JW TI SPACE-TIME INTEGRITY OF IMPROVED STRATOSPHERIC AND MESOSPHERIC SOUNDER AND MICROWAVE LIMB SOUNDER TEMPERATURE-FIELDS AT KELVIN WAVE SCALES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SBUV OZONE DATA; EQUATORIAL; OSCILLATIONS AB Space-time analyses, which are sensitive to details of retrieval and gridding processes not seen in zonal and time means, are used to investigate the integrity of version 8 gridded retrieved temperatures from the improved stratospheric and mesospheric sounder (ISAMS) on the upper atmosphere research satellite (UARS). This note presents results of such analyses applied to ISAMS tropical data. Comparisons are made with microwave limb sounder (MLS), also on UARS, temperatures. Prominent zonal wave number 1 features are observed with characteristics similar to those expected for Kelvin waves. Time versus longitude plots reveal quasi-regular eastward phase progression from November 1991 to mid-January 1992. The perturbations extend throughout the upper stratosphere and lower mesosphere (altitudes of 32-64 km), exhibiting peak-to-peak amplitudes of up to 2 degrees-3 degrees it and periods from similar to 2 weeks in midstratosphere to similar to 1 week at higher altitudes. Faster Kelvin waves with periods of 3-5 days are also found in the lower mesosphere. Height versus time plots reveal downward phase and upward group velocities, consistent with forcing from below. Vertical wavelengths are similar to 20 km for the slower mode and about twice this scale for the faster 3 to 5-day mode. The features are trapped within +/-10 degrees-15 degrees bf the equator. Kelvin wave signatures in ISAMS and MLS temperatures are compared at 10 and 1 hPa. Good agreement is found, illustrating the internal consistency and ability of both ISAMS and MLS temperature grids to capture relatively small amplitude features with space-time scales of fast, zonally asymmetric equatorial modes. C1 CALTECH, JET PROP LAB, PASADENA, CA USA. UNIV OXFORD, DEPT ATMOSPHER OCEAN & PLANETARY PHYS, OXFORD, ENGLAND. RP STONE, EM (reprint author), IOWA STATE UNIV SCI & TECHNOL, DEPT PHYS & ASTRON, AMES, IA 50011 USA. NR 23 TC 10 Z9 10 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1995 VL 100 IS D7 BP 14089 EP 14096 DI 10.1029/95JD01171 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK570 UT WOS:A1995RK57000023 ER PT J AU DENNING, AS FUNG, IY RANDALL, D AF DENNING, AS FUNG, IY RANDALL, D TI LATITUDINAL GRADIENT OF ATMOSPHERIC CO2 DUE TO SEASONAL EXCHANGE WITH LAND BIOTA SO NATURE LA English DT Article ID GENERAL-CIRCULATION MODEL; PLANETARY BOUNDARY-LAYER; CARBON-DIOXIDE; GLOBAL DISTRIBUTION; BIOSPHERE; VARIABILITY; BUDGET; SINKS AB THE concentration of carbon dioxide in the atmosphere is increasing, largely because of fossil-fuel combustion, but the rate of increase is only about half of the total emission rate(1). The balance of the carbon must be taken up in the oceans and the terrestrial biosphere, but the relative importance of each of these sinks-as well as their geographical distribution and the uptake mechanisms involved-are still a matter of debate(1-4). Measurements of CO2 concentrations at remote marine sites(5-9) have been used with numerical models of atmospheric transport to deduce the location, nature and magnitude of these carbon sinks(2,10-19). One of the most important constraints on such estimates is the observed interhemispheric gradient in atmospheric CO2 concentration. Published models that simulate the transport of trace gases suggest that the gradient is primarily due to interhemispheric differences in fossil-fuel emissions, with small contributions arising from natural exchange of CO2 with the various carbon reservoirs. Here we use a full atmospheric general circulation model with a more realistic representation of turbulent mixing near the ground to investigate CO2 transport. We find that the latitudinal (meridional) gradient imposed by the seasonal terrestrial biota is nearly half as strong as that imposed by fossil-fuel emissions. Such a contribution implies that the sinks of atmospheric CO2 in the Northern Hemisphere must be stronger than previously suggested. C1 NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025. UNIV VICTORIA,SCH EARTH & OCEAN SCI,VICTORIA,BC V8W 2Y2,CANADA. RP DENNING, AS (reprint author), COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80521, USA. RI Denning, Scott/F-4974-2011; Randall, David/E-6113-2011 OI Denning, Scott/0000-0003-3032-7875; Randall, David/0000-0001-6935-4112 NR 31 TC 270 Z9 275 U1 1 U2 24 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JUL 20 PY 1995 VL 376 IS 6537 BP 240 EP 243 DI 10.1038/376240a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RK331 UT WOS:A1995RK33100042 ER PT J AU FEBVRE, P SALEZ, M MCGRATH, WR BUMBLE, B LEDUC, HG AF FEBVRE, P SALEZ, M MCGRATH, WR BUMBLE, B LEDUC, HG TI PERFORMANCE LIMITATIONS OF NIOBIUM-BASED SUBMILLIMETER-WAVE QUASI-PARTICLE MIXERS OPERATING NEAR THE GAP FREQUENCY SO APPLIED PHYSICS LETTERS LA English DT Article ID TUNNEL JUNCTION MIXERS AB We have measured the noise temperature of heterodyne receivers employing Nb/AlOx/Nb tunnel junction mixers at frequencies ranging from 70% to 93% of the gap frequency of niobium (similar to 700 GHz). The sensitivity of the receiver is decreased by the overlap of the n=l and n=2 photon steps of opposite sign. At bias voltages where these photon steps overlap, there is an increase in receiver noise up to 50%. Theoretical calculations using the Tucker theory agree well with the observed mixer performance. This overlap already affects the receiver operation for best performance at frequencies well below 700 GHz. (C) 1995 American institute of Physics. C1 OBSERV PARIS,DEMIRM,F-75014 PARIS,FRANCE. RP FEBVRE, P (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 11 TC 3 Z9 3 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 17 PY 1995 VL 67 IS 3 BP 424 EP 426 DI 10.1063/1.114620 PG 3 WC Physics, Applied SC Physics GA RK396 UT WOS:A1995RK39600043 ER PT J AU SCHNEEGURT, MA ARIELI, B MCKEEHEN, JD STEPHENS, SD NIELSEN, SS SAHA, PR TRUMBO, PR SHERMAN, LA AF SCHNEEGURT, MA ARIELI, B MCKEEHEN, JD STEPHENS, SD NIELSEN, SS SAHA, PR TRUMBO, PR SHERMAN, LA TI COMPOSITIONAL AND TOXICOLOGICAL EVALUATION OF THE DIAZOTROPHIC CYANOBACTERIUM, CYANOTHECE SP STRAIN ATCC-51142 SO AQUACULTURE LA English DT Article DE CYANOBACTERIA, HUMAN NUTRITION; CYANOTHECE; TOXICOLOGY ID BLUE-GREEN-ALGAE; FATTY-ACID COMPOSITION AB Compositional analyses of Cyanothece sp. strain ATCC 51142 showed high protein (50-60%) and low fat (0.4-1%) content, and the ability to synthesize vitamin B-12. The amino acid profile indicated that Cyanothece sp. was a balanced protein source. Fatty acids of the 18:3n-3 type were also present. Mineral analyses indicated the cellular biomass may be a good source of Fe, Zn, and Na. Caloric content was 4.5 to 5.1 kcal g dry weight(-1) and the carbon content was approximately 40% on a dry weight basis. Nitrogen content was 8 to 9% on a dry weight basis and total nucleic acids were 1.3% on a dry weight basis, Short-term feeding studies in rats followed by histopathology found no toxicity or dietary incompatibility problems. The level of uric acid and allantoin in urine and tissues was low, suggesting no excess of nucleic acids, as sometimes reported in the past for a cyanobacteria-containing diet. The current work discusses the potential implications of these results for human nutrition applications. C1 PURDUE UNIV,NASA,SPECIALIZED CTR RES & TRAINING,DEPT SCI BIOL,W LAFAYETTE,IN 47907. PURDUE UNIV,NASA,SPECIALIZED CTR RES & TRAINING,DEPT FOOD SCI,W LAFAYETTE,IN 47907. PURDUE UNIV,NASA,SPECIALIZED CTR RES & TRAINING,DEPT FOOD & NUTR,W LAFAYETTE,IN 47907. NR 22 TC 7 Z9 8 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD JUL 15 PY 1995 VL 134 IS 3-4 BP 339 EP 349 DI 10.1016/0044-8486(95)00054-6 PG 11 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA RU491 UT WOS:A1995RU49100014 PM 11539278 ER PT J AU GUHATHAKURTA, M FISHER, RR AF GUHATHAKURTA, M FISHER, RR TI CORONAL STREAMERS AND FINE-SCALE STRUCTURES OF THE LOW-LATITUDE CORONA AS DETECTED WITH SPARTAN-201-01 WHITE-LIGHT CORONAGRAPH SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The solar corona was observed with an externally occulted White Light Coronagraph carried on the SPARTAN 201-01 spacecraft for a 47 hour period beginning on April 11, 1993. At this phase of the descending solar magnetic activity cycle there were well developed coronal helmet streamers located over both the east and west limbs of the sun. Of additional interest in the SPARTAN data are the finer scale streamer structures observed in the low latitude corona which are partially resolved by the SP201-01 instrument. The purpose of this investigation was to determine the physical and morphological characteristics of the streamers and the fine scale ray structures observed in the region between streamers. A comparison of these low latitude rays with the polar rays observed in the north and south polar holes during the same flight suggest that they have similar morphology and physical characteristics. C1 CATHOLIC UNIV AMER,DEPT PHYS,WASHINGTON,DC 20064. RP GUHATHAKURTA, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 682,GREENBELT,MD 20771, USA. NR 8 TC 36 Z9 36 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1841 EP 1844 DI 10.1029/95GL01603 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000001 ER PT J AU SZABO, A LEPPING, RP KING, JH AF SZABO, A LEPPING, RP KING, JH TI MAGNETIC-FIELD OBSERVATIONS OF THE 1.3-YEAR SOLAR-WIND OSCILLATION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ACTIVITY INDEXES; PERIODICITIES; IRRADIANCE; EUV AB A 1.3-year oscillation in the IMP-8 and Voyager 2 solar wind plasma radial speed observations for the period of 1987-94 was recently reported [Richardson et al., 1994]. The same periodicity is identified for the same time period in the North-South component of the interplanetary magnetic field at 1 AU when studied with a dynamic power spectrum. This observation sheds new light on the nature of these unusual oscillations. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,GREENBELT,MD 20771. RP SZABO, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 25 TC 34 Z9 35 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1845 EP 1848 DI 10.1029/95GL01737 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000002 ER PT J AU JOHNSON, DG TRAUB, WA CHANCE, KV JUCKS, KW STACHNIK, RA AF JOHNSON, DG TRAUB, WA CHANCE, KV JUCKS, KW STACHNIK, RA TI ESTIMATING THE ABUNDANCE OF CLO FROM SIMULTANEOUS REMOTE-SENSING MEASUREMENTS OF HO2, OH, AND HOCL SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Using a simple photochemical model we derive the mixing ratio profile of ClO in the altitude range 20-38 km from simultaneous measurements of HO2, OH, HOCl, temperature, pressure, and ozone. The measurements were made with the FIRS-2 far-infrared spectrometer during a balloon flight on September 29, 1992. We compare the derived ClO with the ClO profile obtained by the SLS instrument while flying on the same gondola. The good agreement between the two profiles validates our simple model and confirms the relevant rate constants and photolysis cross sections. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP JOHNSON, DG (reprint author), SMITHSONIAN ASTROPHYS OBSERV,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. RI Johnson, David/F-2376-2015; OI Johnson, David/0000-0003-4399-5653; Chance, Kelly/0000-0002-7339-7577 NR 9 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1869 EP 1871 DI 10.1029/95GL01249 PG 3 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000008 ER PT J AU YUE, GK POOLE, LR MCCORMICK, MP VEIGA, RE WANG, PH RIZI, V MASCI, F DALTORIO, A VISCONTI, G AF YUE, GK POOLE, LR MCCORMICK, MP VEIGA, RE WANG, PH RIZI, V MASCI, F DALTORIO, A VISCONTI, G TI COMPARING SIMULTANEOUS STRATOSPHERIC AEROSOL AND OZONE LIDAR MEASUREMENTS WITH SAGE-II DATA AFTER THE MOUNT-PINATUBO ERUPTION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MT-PINATUBO; VOLCANIC-ERUPTION; SIZE DISTRIBUTION; EL CHICHON; HAWAII; PLUME AB Stratospheric aerosol and ozone profiles obtained simultaneously from the lidar station at the University of L'Aquila (42.35 degrees, 13.33 degrees E, 683m above sea level) during the first months following the eruption of Mount Pinatubo are compared with corresponding nearby Stratospheric Aerosol and Gas Experiment (SAGE) II profiles. The agreement between the two data sets is found to be reasonably good. The temporal change of aerosol profiles obtained by both techniques showed the intrusion and growth of Pinatubo aerosols. In addition, ozone concentration profiles derived from an empirical time-series model based on SAGE II ozone data obtained before the Pinatubo eruption are compared with measured profiles. Good agreement is shown in the 1991 profiles, but ozone concentrations measured in January 1992 were reduced relative to time-series model estimates. Possible reasons for the differences between measured and model-based ozone profiles are discussed. C1 SCI APPLICAT INT CORP,HAMPTON,VA 23666. SCI & TECHNOL CORP,HAMPTON,VA 23666. UNIV AQUILA,DIPARTIMENTO FIS,I-67010 COPPITO,ITALY. IST NAZL GEOFIS,I-00143 ROME,ITALY. RP YUE, GK (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 28 TC 10 Z9 10 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1881 EP 1884 DI 10.1029/95GL00796 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000011 ER PT J AU CHOU, MD ARKING, A OTTERMAN, J RIDGWAY, WL AF CHOU, MD ARKING, A OTTERMAN, J RIDGWAY, WL TI THE EFFECT OF CLOUDS ON ATMOSPHERIC ABSORPTION OF SOLAR-RADIATION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BUDGET EXPERIMENT; CLIMATE; PARAMETERIZATIONS AB It has long been an issue of whether clouds enhance or reduce atmospheric absorption of solar radiation. Radiative transfer calculations show that the effect of clouds on atmospheric absorption of solar radiation depends strongly on the solar zenith angle, cloud height and surface albedo. Over wide ranges of these parameters, clouds have the effect of reducing atmospheric solar heating. This result can be altered if the cloud specific absorption is amplified by a factor of 5. For the ratio of cloud forcing at the surface to that at the top of the atmosphere to reach 1.5, as suggested by recent observational analyses, cloud specific absorption would be required to increase by a factor of approximate to 40 beyond what has been determined by in situ aircraft measurements. Since there is no observational evidence to support such strong absorption, the excess cloud absorption, if it occurs, can only be explained by some unknown factors other than the cloud specific absorption. C1 JOHNS HOPKINS UNIV, BALTIMORE, MD 21218 USA. LAND ATMOSPHERE OCEAN RES, GREENBELT, MD USA. APPL RES CORP, LANDOVER, MD 20785 USA. RP NASA, GODDARD SPACE FLIGHT CTR, CODE 913, GREENBELT, MD 20771 USA. NR 21 TC 35 Z9 35 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1885 EP 1888 DI 10.1029/95GL01350 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000012 ER PT J AU RICHARDSON, WP STEIN, S STEIN, CA ZUBER, MT AF RICHARDSON, WP STEIN, S STEIN, CA ZUBER, MT TI GEOID DATA AND THERMAL STRUCTURE OF THE OCEANIC LITHOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MENDOCINO FRACTURE-ZONE; SEA-FLOOR DEPTH; HEAT-FLOW; HEIGHT DATA; AGE; ANOMALIES; CONSTRAINTS; EVOLUTION; STRESSES; MODELS AB A long-standing question is whether old oceanic lithosphere continues cooling as the boundary layer of a halfspace or approaches thermal equilibrium, as modeled by a finite thickness plate. Although the latter is the most direct inference from seafloor depths and heat flow, other explanations have been proposed. We investigate this issue using published results for the derivative of the oceanic geoid with age estimated from geoid offsets across fracture zones. Such data have not been used extensively in analyses of the thermal evolution of the lithosphere, primarily because they are inconsistent with two commonly used thermal models: a halfspace or a 125-km-thick plate. Recent studies, however, find that depth and heat flow data are better fit by a thinner (95 km) plate model. We thus compile published geoid slope results, and find that these data, though scattered, can discriminate between the models. Geoid slope changes with age, rather than being constant as predicted for a cooling halfspace. This variation is greater than predicted for a thick plate and is better fit by a thin plate. Geoid data should thus be useful for improving thermal models of the lithosphere. C1 UNIV ILLINOIS,DEPT GEOL SCI,CHICAGO,IL 60607. JOHNS HOPKINS UNIV,DEPT EARTH & PLANETARY SCI,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. RP RICHARDSON, WP (reprint author), NORTHWESTERN UNIV,DEPT GEOL SCI,EVANSTON,IL 60208, USA. NR 30 TC 11 Z9 11 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1995 VL 22 IS 14 BP 1913 EP 1916 DI 10.1029/95GL01595 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK290 UT WOS:A1995RK29000019 ER PT J AU GREEN, S AF GREEN, S TI COMMENT ON SYMMETRY OF THE INTERACTION BETWEEN AN ASYMMETRIC RIGID ROTOR AND A LINEAR RIGID ROTOR SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COLLISION-INDUCED TRANSITIONS; ROTATIONAL-EXCITATION; PROPENSITY RULES; CROSS-SECTIONS; RATE CONSTANTS; ORTHO-H2; PARA-H2; NH3; SCATTERING; MOLECULES AB In fitting an ab initio potential for H2O-H-2, Phillips et al. [J. Chem. Phys. 101, 5824 (1994)] excluded certain terms in the angular expansion they believed to vanish because of ''the requirement that the potential is invariant to inversion of all coordinates through the origin.'' However, there has been some question in the literature as to whether these terms must, in fact, vanish owing to spatial inversion symmetry. By providing counterexamples, it is demonstrated here that this is not required by fundamental spatial symmetry. However, these terms do appear to vanish for realistic molecular interactions and this symmetry may arise from the two-body nature of the electrostatic Hamiltonian. RP GREEN, S (reprint author), NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, NEW YORK, NY 10025 USA. NR 24 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 15 PY 1995 VL 103 IS 3 BP 1035 EP 1042 DI 10.1063/1.469813 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RJ371 UT WOS:A1995RJ37100019 ER PT J AU MILLER, RN BUSALACCHI, AJ HACKERT, EC AF MILLER, RN BUSALACCHI, AJ HACKERT, EC TI SEA-SURFACE TOPOGRAPHY FIELDS OF THE TROPICAL PACIFIC FROM DATA ASSIMILATION SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID EXPENDABLE BATHYTHERMOGRAPH DATA; ATLANTIC-OCEAN; DYNAMIC HEIGHT; HEAT-CONTENT; XBT DATA; MODEL; LEVEL; CIRCULATION; TRANSPORTS; WINDS AB Time series of maps of monthly tropical Pacific dynamic topography anomalies from 1979 through 1985 were constructed by means of assimilation of tide gauge and expendable bathythermograph (XBT) data into a linear model driven by observed winds. Estimates of error statistics were calculated and compared to actual differences between hindcasts and observations. Four experiments were performed as follows: one with no assimilation, one with assimiation of sea level anomaly data from eight selected island tide gauge stations, one with assimilation of dynamic height anomalies derived from XBT data, and one with both XBT and tide gauge data assimilated. Data from seven additional tide gauge stations were withheld from the assimilation process and used for verification in all four experiments. Statistical objective maps based on data alone were also constructed for comparison purposes. The dynamic response of the model without assimilation was, in general, weaker than the observed response. Assimilation resulted in enhanced signal amplitude in al three assimilation experiments. RMS amplitudes of statistical objective maps were only strong near observing points. In large data-void regions these maps show amplitudes even weaker than the wind-driven model without assimilation. With. few exceptions the error estimates generated by the Kalman filter appeared quite reasonable. Since the error processes cannot be assumed to be white or stationary, we could find no straightforward way to test the formal statistical hypothesis that the time series of differences between the filter output and the actual observations were drawn from a population with statistics given by the Kalman filter estimates. The autocovariance of the innovation sequence, i.e., the sequence of differences between forecasts before assimilation and observations, has long been used as an indicator of how close a filter is to optimality. We found that the best filter we could devise was still short of the goal of producing a white innovation sequence. In this and earlier studies, little sensitivity has been found to the parameters under our direct control. Extensive changes in the assumed error statistics make only marginal differences. The same is true for long time and space scale behavior of different models with richer physics and finer resolution. Better data assimilation results will probably require relaxation of the assumptions of stationarity and serial independence of the errors. Formulation of such detailed noise models will require longer time series, with the attendant problems of matching very different data sets. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771. HUGHES STX CORP,GREENBELT,MD 20771. RP MILLER, RN (reprint author), OREGON STATE UNIV,COLL OCEAN & ATMOSPHER SCI,OCEANOG ADM BLDG 104,CORVALLIS,OR 97331, USA. RI Hackert, Eric/A-9915-2011 NR 46 TC 18 Z9 18 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1995 VL 100 IS C7 BP 13389 EP 13425 DI 10.1029/95JC00721 PG 37 WC Oceanography SC Oceanography GA RJ356 UT WOS:A1995RJ35600022 ER PT J AU NGHIEM, SV KWOK, R YUEH, SH DRINKWATER, MR AF NGHIEM, SV KWOK, R YUEH, SH DRINKWATER, MR TI POLARIMETRIC SIGNATURES OF SEA-ICE .1. THEORETICAL-MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID STRONG PERMITTIVITY FLUCTUATIONS; MICROWAVE-FREQUENCIES; DIELECTRIC-PROPERTIES; SCATTERING; SNOW; CONSTANT; EXCHANGE; BRINE; MEDIA AB Physical, structural, and electromagnetic properties and interrelating processes in sea ice are used to develop a composite model for polarimetric backscattering signatures of sea ice. Physical properties of sea ice constituents such as ice, brine, air, and salt are presented in terms of their effects on electromagnetic wave interactions. Sea ice structure and geometry of scatterers are related to wave propagation, attenuation, and scattering. Temperature and salinity, which are determining factors for the thermodynamic phase distribution in sea ice, are consistently used to derive both effective permittivities and polarimetric scattering coefficients. Polarimetric signatures of sea ice depend on crystal sizes and brine volumes, which are affected by ice growth rates. Desalination by brine expulsion, drainage, or other mechanisms modifies wave penetration and scattering. Sea ice signatures are further complicated by surface conditions such as rough interfaces, hummocks, snow cover, brine skim, or slush layer. Based on the same set of geophysical parameters characterizing sea ice, a composite model is developed to calculate effective permittivities and backscattering covariance matrices at microwave frequencies for interpretation of sea ice polarimetric signatures. RP NGHIEM, SV (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Drinkwater, Mark/C-2478-2011 OI Kwok, Ron/0000-0003-4051-5896; Drinkwater, Mark/0000-0002-9250-3806 NR 48 TC 49 Z9 49 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1995 VL 100 IS C7 BP 13665 EP 13679 DI 10.1029/95JC00937 PG 15 WC Oceanography SC Oceanography GA RJ356 UT WOS:A1995RJ35600040 ER PT J AU NGHIEM, SV KWOK, R YUEH, SH DRINKWATER, MR AF NGHIEM, SV KWOK, R YUEH, SH DRINKWATER, MR TI POLARIMETRIC SIGNATURES OF SEA-ICE .2. EXPERIMENTAL-OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID COMPLEX-DIELECTRIC-CONSTANT; MICROWAVE-FREQUENCIES; BRINE; SNOW; GHZ AB Experimental observations of polarimetric signatures are presented for sea ice in the Beaufort Sea under cold winter conditions and interpreted with the composite model developed in Part 1. Polarimetric data were acquired in March 1988 with the Jet Propulsion Laboratory multifrequency airborne synthetic aperture radar (SAR) during the Beaufort Sea Flight Campaign. The experimental area was located near 75 degrees N latitude and spanned 140 degrees-145 degrees W longitude. Selected sea ice scenes contain various ice types, including multiyear, thick first-year, and thin lead ice. Additionally, the C band SAR on the first European Remote Sensing Satellite provides supplementary backscattering data of winter Beaufort Sea ice for small incident angles (20 degrees-26 degrees) at vertical polarization. Sea ice characterization and environmental data used in the model were collected at the Applied Physics Laboratory drifting ice station to the northeast of Prudhoe Bay; additional data from field and laboratory experiments are also utilized in this analysis. The model relates sea ice polarimetric backscattering signatures to physical, structural, and electromagnetic properties of sea ice. Scattering mechanisms contributing to sea ice signatures are explained, and sensitivities of polarimetric signatures to sea ice characterization parameters are studied. RP NGHIEM, SV (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 300-235,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Drinkwater, Mark/C-2478-2011 OI Kwok, Ron/0000-0003-4051-5896; Drinkwater, Mark/0000-0002-9250-3806 NR 34 TC 48 Z9 48 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1995 VL 100 IS C7 BP 13681 EP 13698 DI 10.1029/95JC00938 PG 18 WC Oceanography SC Oceanography GA RJ356 UT WOS:A1995RJ35600041 ER PT J AU YURTSEVER, U AF YURTSEVER, U TI REMARKS ON THE AVERAGED NULL ENERGY CONDITION IN QUANTUM-FIELD THEORY SO PHYSICAL REVIEW D LA English DT Note AB I propose a simple generalization of the ANEC (averaged null energy condition), in which the right-hand side of the ANEC inequality is replaced by a finite (but in general negative) state-independent lower bound. It is plausible that unlike the original ANEC this version might hold generally in four-dimensional curved spacetime. I study some of the implications of the generalized ANEC, and show, in particular, that if it holds in static traversable wormhole spacetimes (which is likely but remains to be shown), then the generalized ANEC rules out macroscopic (but not necessarily microscopic, Planck-size) static wormholes. C1 CALTECH,PASADENA,CA 91125. RP YURTSEVER, U (reprint author), CALTECH,JET PROP LAB 169-327,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 10 TC 12 Z9 12 U1 0 U2 0 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 JUL 15 PY 1995 VL 52 IS 2 BP R564 EP R568 DI 10.1103/PhysRevD.52.R564 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RJ948 UT WOS:A1995RJ94800002 ER PT J AU OGBUJI, LUJT HARDING, DR AF OGBUJI, LUJT HARDING, DR TI A NOVEL METHOD FOR DETERMINING THE STRENGTH OF PECVD SILICON (OXY)NITRIDE FILMS SO THIN SOLID FILMS LA English DT Article DE CERAMICS; NITRIDES; SILICON; SURFACE STRESS ID STRESS AB A technique is described for determining the strength of plasma-enhanced chemical vapor-deposited (PECVD) thin films from the bursting size of microscopic bubbles formed by escaping volatiles upon annealing. The strength of a PECVD SiOxNy (silicon oxynitride) film is estimated using this approach. RP OGBUJI, LUJT (reprint author), NASA,LEWIS RES CTR,NYMA,CLEVELAND,OH 44135, USA. NR 7 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUL 15 PY 1995 VL 263 IS 2 BP 194 EP 197 DI 10.1016/0040-6090(95)06578-4 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA RM783 UT WOS:A1995RM78300010 ER PT J AU FRANCISCO, JS SANDER, SP AF FRANCISCO, JS SANDER, SP TI A COMPUTATIONAL STUDY OF DISSOCIATION PATHWAYS IN THE FOCL-FCL0 SYSTEM SO CHEMICAL PHYSICS LETTERS LA English DT Article ID QUADRATIC CONFIGURATION-INTERACTION; ELECTRON CORRELATION; BRUECKNER AB Ab initio molecular orbital calculations have been carried out to determine the relative stabilities and decomposition pathways of FOCl and FClO. Second-order Moller-Plesset perturbation theory along with quadratic configuration interaction and Brueckner doubles including perturbational corrections of connected triple excitation (BD(T)) methods are used. We find that FClO is more stable than FOCI. An examination of the potential energy surface for the reaction of oxygen atoms with FCl shows that only FClO should be produced. This is consistent with the experimental observation from matrix studies. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 21 TC 8 Z9 8 U1 0 U2 0 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 JUL 14 PY 1995 VL 241 IS 1-2 BP 33 EP 38 DI 10.1016/0009-2614(95)00613-9 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RK762 UT WOS:A1995RK76200006 ER PT J AU NOEVER, DA AF NOEVER, DA TI KINETIC EFFECTS IN PROTEIN CRYSTALS .1. THE ROLE OF HYDRATION IN PROTEIN AGGREGATION SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID EGG-WHITE LYSOZYME; LIGHT-SCATTERING METHOD; GROWTH; MICROGRAVITY; CRYSTALLIZATION; SURFACE AB Crystallizing proteins presents long-standing problems with sluggish kinetics and competing growth-limiting factors in solution. This work examines potential limiting factors arising from protein-water interactions and protein-protein aggregation. Since a hydrated shell shields bare protein contacts, multiple layers of highly viscous water impose restrictions on protein addition. If proteins attach to the crystal as aggregates, they are found to be particularly sensitive to misalignments and denaturation. The modelling extends to include the protein's shape as a fractal, the number of its binding sites and possible effects of flow-induced shear. It concludes that: (i) when protein-water interactions are taken into account, convective shear approaches velocities of the order of magnitude that alter protein kinetics; (ii) protein aggregation puts narrow tolerances on correct molecular alignments; and (iii) a protein's characteristic 'stringy' shape as a fractal can favour aggregates compared with the monomer as a growth unit. A model for protein addition as an extensible, tethered molecule is proposed and examined against flow strengths and random thermal vibrations. Comparison of the protein model with experimental lysozyme results suggests that forced fluid flows as small as 100 mu m s(-1) can disrupt protein attachment and thus detrimentally limit crystal growth on a microscospic scale. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, ES 76, HUNTSVILLE, AL 35812 USA. NR 46 TC 5 Z9 5 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 EI 1361-6463 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD JUL 14 PY 1995 VL 28 IS 7 BP 1384 EP 1392 DI 10.1088/0022-3727/28/7/016 PG 9 WC Physics, Applied SC Physics GA RK879 UT WOS:A1995RK87900016 ER PT J AU NOEVER, DA AF NOEVER, DA TI KINETIC EFFECTS IN PROTEIN CRYSTALS .2. GEOMETRY AND MISALIGNMENT TOLERANCE WITH EXPERIMENTAL RESULTS SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID GROWTH AB A geometric model for protein crystallization and attachment kinetics is considered. The tolerance for misalignment is found for random versus preferred orientation. The protein growth unit can either be modelled as a sphere or as a rough and stringy fractal. It is found that the larger surface area available for a fractal makes its attachment orientation more critical than for a solidly modelled protein. The magnitude of such tolerance increases threefold compared with a simple sphere. The probability of successful (aligned) binding varies as the exponential of the number of attachment sites, so larger protein building blocks place a premium on correct orientation. Larger proteins (more residues) or oligomeric growth units are thus predicted to show marked sensitivity to solution conditions that favour or disfavour preferred orientation. For an octameric (N = 8) fractal aggregate, these tolerances reach a 1000-fold narrowing compared with single molecular spheres. Very weak electric fields (V) as low as 50D(2), where D is the surface diffusion coefficient, are found to be of the same order of magnitude as the randomizing surface diffusion and thus offer one experimentally realizable condition for setting a particular molecular alignment. In conclusion, protein geometry is found to be a significant factor in determining crystallization and attachment kinetics in solution-sensitive growth. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES 76,HUNTSVILLE,AL 35812, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD JUL 14 PY 1995 VL 28 IS 7 BP 1393 EP 1399 DI 10.1088/0022-3727/28/7/017 PG 7 WC Physics, Applied SC Physics GA RK879 UT WOS:A1995RK87900017 ER PT J AU LINDERMAN, JK WHITTALL, JB GOSSELINK, KL WANG, TJ MUKKU, VR BOOTH, FW GRINDELAND, RE AF LINDERMAN, JK WHITTALL, JB GOSSELINK, KL WANG, TJ MUKKU, VR BOOTH, FW GRINDELAND, RE TI STIMULATION OF MYOFIBRILLAR PROTEIN-SYNTHESIS IN HINDLIMB SUSPENDED RATS BY RESISTANCE EXERCISE AND GROWTH-HORMONE SO LIFE SCIENCES LA English DT Article DE HINDLIMB SUSPENSION; RESISTANCE EXERCISE; GROWTH HORMONE ID SKELETAL-MUSCLE; SOLEUS MUSCLE; SPACEFLIGHT; ATROPHY; SUSPENSION; METABOLISM; TURNOVER AB The objective of this study was to determine the ability of a single bout of resistance exercise alone or in combination with recombinant human growth hormone (rhGH) to stimulate myofibrillar protein synthesis (Ks) in hindlimb suspended (HLS) adult female rats. Plantar flexor muscles were stimulated with resistance exercise, consisting of 10 repetitions of ladder climbing on a Im grid (85 degrees), carrying an additional 50% of their body weight attached to their tails. Saline or rhGH (1 mg/kg) was administered 30' prior to exercise, and Ks was determined with a constant infusion of H-3-Leucine at 15', 60', 180', and 360' following exercise. Three days of HLS depressed Ks similar to 65% and 30-40% in the soleus and gastrocnemius muscles, respectively (p less than or equal to 0.05). Exercise increased soleus Ks in saline-treated rats 149% 60' following exercise (p less than or equal to 0.05), decaying to that of non-exercised animals during the next 5 hours. Relative to suspended, non-exercised rats rhGH+exercise increased soleus Ks 84%, 108%, and 72% at 15', 60' and 360' following exercise (p less than or equal to 0.05). Gastrocnemius Ks was not significantly increased by exercise or the combination of rhGH and exercise up to 360' post-exercise. Results from this study indicate that resistance exercise stimulated Ks 60' post-exercise in the soleus of HLS rats, with no apparent effect of rhGH to enhance or prolong exercise-induced stimulation. Results suggests that exercise frequency may be important to maintenance of the slow-twitch soleus during non-weightbearing, but that the ability of resistance exercise to maintain myofibriliar protein content in the gastrocnemius of hindlimb suspended rats cannot be explained by acute stimulation of synthesis. C1 UNIV TEXAS,SCH MED,DEPT PHYSIOL & CELL BIOL,HOUSTON,TX 77225. GENENTECH INC,S SAN FRANCISCO,CA 94080. RP LINDERMAN, JK (reprint author), NASA,AMES RES CTR,DIV LIFE SCI 239-11,MOFFETT FIELD,CA 94035, USA. NR 25 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0024-3205 J9 LIFE SCI JI Life Sci. PD JUL 14 PY 1995 VL 57 IS 8 BP 755 EP 762 DI 10.1016/0024-3205(95)02003-2 PG 8 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA RJ739 UT WOS:A1995RJ73900003 PM 7637549 ER PT J AU CHARLES, CD RIND, D JOUZEL, J KOSTER, RD FAIRBANKS, RG AF CHARLES, CD RIND, D JOUZEL, J KOSTER, RD FAIRBANKS, RG TI SEASONAL PRECIPITATION TIMING AND ICE CORE RECORDS SO SCIENCE LA English DT Article C1 GODDARD INST SPACE STUDIES,NEW YORK,NY 10028. CTR ETUD SACLAY,MODELISAT CLIMAT & ENVIRONNEMENT LAB,F-91191 GIF SUR YVETTE,FRANCE. LAB GLACIOL & GEOPHYS ENVIRONM,CNRS,F-38402 ST MARTIN DHERES,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20904. COLUMBIA UNIV,DEPT GEOL SCI,NEW YORK,NY 10025. LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964. RP CHARLES, CD (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 5 TC 13 Z9 14 U1 1 U2 7 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUL 14 PY 1995 VL 269 IS 5221 BP 247 EP 248 DI 10.1126/science.269.5221.247 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RJ029 UT WOS:A1995RJ02900048 PM 17789853 ER PT J AU HSU, KJ DEMORE, WB AF HSU, KJ DEMORE, WB TI TEMPERATURE-DEPENDENT RATE CONSTANTS AND SUBSTITUENT EFFECTS FOR THE REACTIONS OF HYDROXYL RADICALS WITH 3 PARTIALLY FLUORINATED ETHERS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID OH AB Rate constants and temperature dependencies for the reactions of OH with CF3OCH3 (HFOC-143a), CF2HOCF2H (HFOC-134), and CF3OCF2H (HFOC-125) were studied using a relative rate technique in the temperature range 298-393 K. The following absolute rate constants were derived: HFOC-143a, 1.9E-12 exp(-1555/T); HFOC-134, 1.9E-12 exp(-2006/T); HFOC-125, 4.7E-13 exp(-2095/T). Units are cm(3) molecule(-1) s(-1). Substituent effects on OH abstraction rate constants are discussed, and it is shown that the CF3O group has an effect on the OH rate constants similar to that of a fluorine atom. The effects are related to changes in the C-H bond energies of the reactants (and thereby the activation energies) rather than changes in the preexponential factors. On the basis of a correlation of rate constants with bond energies, the respective D(C-H) bond strengths in the three ethers are found to be 102, 104, and 106 kcal/mol, with an uncertainty of about 1 kcal/mol. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 9 TC 77 Z9 78 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUL 13 PY 1995 VL 99 IS 28 BP 11141 EP 11146 DI 10.1021/j100028a014 PG 6 WC Chemistry, Physical SC Chemistry GA RK018 UT WOS:A1995RK01800014 ER PT J AU LINDH, R LEE, TJ BERNHARDSSON, A PERSSON, BJ KARLSTROM, G AF LINDH, R LEE, TJ BERNHARDSSON, A PERSSON, BJ KARLSTROM, G TI EXTENDED AB-INITIO AND THEORETICAL THERMODYNAMICS STUDIES OF THE BERGMAN REACTION AND THE ENERGY SPLITTING OF THE SINGLET O-BENZYNES, M-BENZYNES, AND P-BENZYNES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID 2ND-ORDER PERTURBATION-THEORY; MOLECULAR WAVE-FUNCTIONS; ANO BASIS-SETS; ANTITUMOR ANTIBIOTICS; ROW ATOMS; CASSCF; FAMILY; SCF; CI; CALICHEMICIN-GAMMA-1 AB The autoaromatization of (Z)-hex-3-ene-1,5-diyne to the singlet biradical p-benzyne has been reinvestigated by state of the art ab initio methods. Previous CCSD(T)/6-31G(d,p) and CASPT2[0]/ANO[C(5s4p2dlf)/H(3s2p)] calculations estimated the reaction heat at 298 K to be 8-10 and 3.9 +/- 3.2 kcal/mol, respectively. Recent NO- and oxygen-dependent trapping experiments and collision-induced dissociation threshold energy experiments estimate the heat of reaction to be 8.5 +/- 1.0 kcal/mol at 470 K (corrected to 9.5 +/- 1.0 kcal/mol at 298 K) and 8.4 +/- 3.0 kcal/mol at 298 K, respectively. New theoretical estimates at 298 K predict the values at the basis set Limit for the CCSD(T) and CASPT2[gl] methods to be 12.7 +/- 2.0 and 5.4 +/- 2.0 kcal/mol, respectively. The experimentally predicted electronic contribution to the heat of activation is 28.6 kcal/mol. This can be compared with 25.5 and 29.8 kcal/mol from the CASPT2[gl] and the CCSD(T) methods, respectively. The new study has a much larger one-particle basis set for the CCSD(T) method as compared to earlier studies. For the CASPT2 investigation the better suited CASPT2[gl] approximation is utilized. The original CASPT2 method, CASPT2[0], systematically favors open-shell systems relative to closed-shell systems. This was previously corrected empirically. The current study shows that the energy difference between CCSD(T) and CASPT2[gl] at the basis set limit is estimated to be 7 +/- 2 kcal/mol. The study also demonstrates that the estimated heat of reaction is very sensitive to the quality of the basis set. In particular CCSD(T)/6-31G(d,p) approach underestimates the basis set limit of the enthalpy by approximately 5 kcal/mol. Furthermore, the relative energies of the p-, m-, and o-benzynes are computed at the CASPT2[gl] and CCSD(T) levels of theory. These results help to explain the discrepancy between the two methods in the case of the Bergman reaction. The deficiency of the CASPT2 method is mainly attributed to the approximate way in which the dynamic correlation is included by perturbation theory. A similar sized error is attributed to the CCSD(T) method due to the approximate way in which near degeneracy effects are included. This combined CCSD(T) and CASPT2[gl] study indicates that the most recent experimental value of the p-benzyne-o-benzyne energy splitting is overestimated. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP LINDH, R (reprint author), LUND UNIV,CTR CHEM,DEPT THEORET CHEM,BOX 124,S-22100 LUND,SWEDEN. RI Karlstrom, Gunnar/A-8290-2010; Lindh, Roland/F-3471-2012; Lee, Timothy/K-2838-2012 OI Lindh, Roland/0000-0001-7567-8295; NR 41 TC 100 Z9 100 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 12 PY 1995 VL 117 IS 27 BP 7186 EP 7194 DI 10.1021/ja00132a019 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA RJ035 UT WOS:A1995RJ03500019 ER PT J AU DOWNIE, JD AF DOWNIE, JD TI OPTICAL CORRELATION OF IMAGES WITH SIGNAL-DEPENDENT NOISE USING CONSTRAINED-MODULATION FILTER DEVICES SO APPLIED OPTICS LA English DT Article ID RECOGNITION; TARGET AB Images with signal-dependent noise present challenges beyond those of images with additive white or colored signal-independent noise in terms of designing the optimal 4-f correlation filter that maximizes correlation-peak signal-to-noise ratio, or combinations of correlation-peak metrics. Determining the proper design becomes more difficult when the filter is to be implemented on a constrained-modulation spatial light modulator device. The design issues involved for updatable optical filters for images with signal-dependent film-grain noise and speckle noise are examined. It is shown that although design of the optimal linear filter in the Fourier domain is impossible far images with signal-dependent noise, proper nonlinear preprocessing of the images allows the application of previously developed design rules for optimal filters to be implemented on constrained-modulation devices. Thus the nonlinear preprocessing becomes necessary for correlation in optical systems with current spatial light modulator technology. These results are illustrated with computer simulations of images with signal-dependent noise correlated with binary-phase-only filters and ternary-phase-amplitude filters. RP DOWNIE, JD (reprint author), NASA, AMES RES CTR, M-S 269-3, MOFFETT FIELD, CA 94035 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 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 JUL 10 PY 1995 VL 34 IS 20 BP 3896 EP 3903 PG 8 WC Optics SC Optics GA RH839 UT WOS:A1995RH83900005 PM 21052212 ER PT J AU HORACK, JM EMSLIE, AG HARMANN, DH AF HORACK, JM EMSLIE, AG HARMANN, DH TI THE EFFECTS OF PURE DENSITY EVOLUTION ON THE BRIGHTNESS DISTRIBUTION OF COSMOLOGICAL GAMMA-RAY BURSTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, THEORY; GAMMA RAYS, BURSTS ID BATSE AB In this work, we explore the effects of burst rate density evolution on the observed brightness distribution of cosmological gamma-ray bursts. Although the brightness distribution of gamma-ray bursts observed by the BATSE experiment has been shown to be consistent with a nonevolving source population observed to redshifts of order unity, evolution of some form is likely to be present in the gamma-ray bursts. Additionally, nonevolving models place significant constraints on the range of observed burst luminosities, which are relaxed if evolution of the burst population is present. In this paper, three analytic forms of density evolution are examined. In general, forms of evolution with densities that increase monotonically with redshift require that the BATSE data correspond to bursts at larger redshifts, or to incorporate a wider range of burst luminosities, or both. Independent estimates of the maximum observed redshift in the BATSE data and/or the range of luminosity from which a large fraction of the observed bursts are drawn therefore allow for constraints to be placed on the amount of evolution that may be present in the burst population. Specifically, if recent measurements obtained from analysis of the BATSE duration distribution of the actual limiting redshift in the BATSE data at z(lim) - 2 are correct, the BATSE N(P) distribution in a Lambda = 0 universe is inconsistent at a level of similar to 3 sigma with nonevolving gamma-ray bursts and some form of evolution in the population is required. The sense of this required source evolution is to provide a higher density, larger luminosities, or both with increasing redshift. C1 UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. RP HORACK, JM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES-84,HUNTSVILLE,AL 35812, USA. RI Horack, John/J-6670-2016 NR 24 TC 18 Z9 18 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP 474 EP 481 DI 10.1086/175891 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF788 UT WOS:A1995RF78800002 ER PT J AU FIERRO, JM ARZOUMANIAN, Z BAILES, M BELL, JF BERTSCH, DL BRAZIER, KTS CHIANG, J DAMICO, N DINGUS, BL ESPOSITO, JA FICHTEL, CE HARTMAN, RC HUNTER, SD JOHNSTON, S KANBACH, G KASPI, VM KNIFFEN, DA LIN, YC LYNE, AG MANCHESTER, RN MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NEL, HI NICE, D NOLAN, PL SCHNEID, EJ SHRIVER, SK SREEKUMAR, P TAYLOR, JH THOMPSON, DJ WILLIS, TD AF FIERRO, JM ARZOUMANIAN, Z BAILES, M BELL, JF BERTSCH, DL BRAZIER, KTS CHIANG, J DAMICO, N DINGUS, BL ESPOSITO, JA FICHTEL, CE HARTMAN, RC HUNTER, SD JOHNSTON, S KANBACH, G KASPI, VM KNIFFEN, DA LIN, YC LYNE, AG MANCHESTER, RN MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NEL, HI NICE, D NOLAN, PL SCHNEID, EJ SHRIVER, SK SREEKUMAR, P TAYLOR, JH THOMPSON, DJ WILLIS, TD TI EGRET HIGH-ENERGY GAMMA-RAY PULSAR STUDIES .2. INDIVIDUAL MILLISECOND PULSARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, OBSERVATIONS; PULSARS, GENERAL ID GLOBULAR-CLUSTERS; BINARY; EVOLUTION; DISCOVERY; TELESCOPE; RADIATION; CATALOG; GAPS AB More than 2 yr of observations performed by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma Ray Observatory (CGRO) are examined for evidence of high-energy gamma-ray emission from individual millisecond pulsars. Upper limits are placed on steady emission. In addition, for those millisecond pulsars for which an accurate timing solution is available, upper limits to pulsed gamma-ray emission are established. The results are compared with predictions of current pulsar gamma-ray emission models. In particular, the absence of a detection of gamma-rays from the nearby millisecond pulsar PSR J0437--4715 severely constrains theories regarding gamma-ray emission from millisecond pulsars. C1 PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,WESTON,ACT 2611,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. UNIV PALERMO,IST FIS,I-40126 BOLOGNA,ITALY. CNR,IST RADIOASTRON,I-40126 BOLOGNA,ITALY. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. UNIV SYDNEY,THEORET ASTROPHYS RES CTR,SYDNEY,NSW 2006,AUSTRALIA. MAX PLANCK INST EXTRATERR PHYS,D-80740 GARCHING,GERMANY. HAMPDEN SYDNEY COLL,HAMPDEN SYDNEY,VA 23943. UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,JODRELL BANK,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. POTCHEFSTROOM UNIV CHRISTIAN HIGHER EDUC,DEPT PHYS,POTCHEFSTROOM 2520,SOUTH AFRICA. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. RP FIERRO, JM (reprint author), STANFORD UNIV,WW HANSEN LABS PHYS,STANFORD,CA 94305, USA. RI Nolan, Patrick/A-5582-2009; D'Amico, Nichi/A-5715-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 49 TC 47 Z9 47 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP 807 EP 812 DI 10.1086/175919 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF788 UT WOS:A1995RF78800030 ER PT J AU LYU, CH BRUHWEILER, FC SMITH, AM AF LYU, CH BRUHWEILER, FC SMITH, AM TI TOMOGRAPHY POWER SPECTRUM TECHNIQUES FOR REMOVAL OF FIXED PATTERN NOISE FROM HUBBLE-SPACE-TELESCOPE SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article DE METHODS, ANALYTICAL; METHODS, DATA ANALYSIS; STARS, INDIVIDUAL (ALPHA GRUIS); ULTRAVIOLET, STARS AB We have developed tomography/power spectrum algorithms to differentiate the intrinsic stellar spectrum from the pronounced fluctuations in the spectrum counts due to photocathode granularity and diode-to-diode gain variations. We have presented the results of four typical high signal-to-noise (SIN) and high-resolution data sets, obtained from the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST), for the bright star alpha Gru to demonstrate various utilities of these techniques. Our algorithms allow the final merged HST spectrum to achieve a higher signal-to-noise ratio, and could be applied to resolve the fixed pattern noise (FPN) problems that would be found in the distorted/degraded detectors in both current and future planned instrumentations, e.g., the GHRS and the second generation Space Telescope Imaging Spectrograph (STIS) for the HST. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP LYU, CH (reprint author), CATHOLIC UNIV AMER,DEPT PHYS,ASTROPHYS PROGRAM,WASHINGTON,DC 20064, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP 880 EP 888 DI 10.1086/175925 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF788 UT WOS:A1995RF78800036 ER PT J AU ASCHWANDEN, MJ SCHWARTZ, RA ALT, DM AF ASCHWANDEN, MJ SCHWARTZ, RA ALT, DM TI ELECTRON TIME-OF-FLIGHT DIFFERENCES IN SOLAR-FLARES SO ASTROPHYSICAL JOURNAL LA English DT Article DE RADIATION MECHANISMS, NONTHERMAL; SUN, CORONA; SUN, FLARES; SUN, PARTICLE EMISSION; SUN, X-RAYS, GAMMA RAYS ID HARD X-RAY; BURSTS; MICROWAVES; MODELS AB In the thick-target model for hard X-ray (HXR) emission in solar flares, electron acceleration is assumed to occur in flaring loops at coronal heights, while HXR bremsstrahlung emission is produced in the chromosphere. Under this assumption, the velocity spectrum of the accelerated electrons causes time-of-flight differences that are expected to result in the lower energy HXRs to be delayed with respect to the higher energies. Here we report on the first observational evidence for such a delay. The electron time-of-flight differences between electrons that produce 25-50 keV and 50-100 keV HXR emission are found to have a distribution with a mean of tau = 16.7 +/- 1.9 ms and a standard deviation of sigma(tau) = 16.8 ms. This result is based on the statistics of 5430 HXR pulses detected during 640 solar flares, recorded in the Discriminator Science Data (DISCSC) burst trigger mode with a time resolution of 64 ms by the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma Ray Observatory (CGRO). From the time-of-flight differences we infer a mean altitude of the acceleration site of H = 7300 +/- 800 km (with a standard deviation of sigma(H) = 7300 km) above the level at which the electrons lose their energy. This derived mean loop height should be considered as a lower limit because it is based on the predominance of time-of-light effects over opposite delay effects caused by pitch-angle scattering or trapping. For the electron density in the flare loops we find an upper limit of n(e) less than or equal to 4 x 10(12) cm(-3), based on the requirement that the electron travel time has to be shorter than the collision time. The relatively small time-of-flight differences correspond typically to only approximate to 3% of the HXR pulse duration, and, therefore, no rapid variation in the spectral slope of the observed HXR spectrum is expected. C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. CASE WESTERN RESERVE UNIV,DEPT ASTRON,CLEVELAND,OH 44106. RP ASCHWANDEN, MJ (reprint author), UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742, USA. NR 23 TC 83 Z9 83 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP 923 EP 935 DI 10.1086/175930 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF788 UT WOS:A1995RF78800041 ER PT J AU BELL, JF BESSELL, MS STAPPERS, BW BAILES, M KASPI, VM AF BELL, JF BESSELL, MS STAPPERS, BW BAILES, M KASPI, VM TI PSR J0045-7319 - A DUAL-LINE BINARY RADIO PULSAR SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, SPECTROSCOPIC; PULSARS, INDIVIDUAL (PSR JOO45-7319); STARS, FUNDAMENTAL PARAMETERS ID SMALL MAGELLANIC CLOUD; STAR COMPANION; NEUTRON STARS; MASSES AB Binary radio pulsars are superb tools for mapping binary orbits because of the precision of the pulse timing method (e.g., Taylor and Weisberg). To date, all orbital parameters for binary pulsars have been derived from observations of the pulsar alone. We present the first observations of the radial velocity variations due to the binary motion of a companion to a radio pulsar. Our results demonstrate that the companion to the Small Magellanic Cloud pulsar J0045-7319 is the B1 V star identified by Kaspi et al. The mass ratio of the system is 6.3 +/- 1.2, which, for a neutron star mass of 1.4 M., implies a mass of 8.8 +/- 1.8 M. for the companion, consistent with the mass expected for a B1 V star. The inclination angle for the binary system is therefore 44 degrees +/- 5 degrees, and the projected rotational velocity of the companion is 113 +/- 10 km s(-1). The heliocentric radial velocity of the binary system is consistent with that of other stars and gas in the same region of the Small Magellanic Cloud. C1 CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. CALTECH,JET PROP LAB,IPAC,PASADENA,CA 91125. RP BELL, JF (reprint author), AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,INST ADV STUDIES,WESTON,ACT 2611,AUSTRALIA. NR 20 TC 36 Z9 36 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP L117 EP L119 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF790 UT WOS:A1995RF79000014 ER PT J AU FISHER, R GUHATHAKURTA, M AF FISHER, R GUHATHAKURTA, M TI PHYSICAL-PROPERTIES OF POLAR CORONAL RAYS AND HOLES AS OBSERVED WITH THE SPARTAN-201-01 CORONAGRAPH SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, CORONA ID SOLAR AB Physical conditions and characteristics of polar coronal rays and polar coronal holes are derived from white-light coronal observations aboard the Spartan 201-01 spacecraft and the ground-based K-coronameter in Mauna Loa, Hawaii, on 1993 April 11-12. An array of polar rays extending from 1.16 to 5.0 R. was observed in both the north and south polar coronal hole regions. They appear as coherent structures at much higher altitudes than previously observed. Densities and scale height temperatures are estimated as a function of radial height for the holes and the rays. These profiles suggest that there is extended heating up to heights of 1.4-2.6 R.. C1 CATHOLIC UNIV AMER,DEPT PHYS,WASHINGTON,DC 20064. RP FISHER, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 682,GREENBELT,MD 20771, USA. NR 15 TC 143 Z9 143 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP L139 EP L142 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF790 UT WOS:A1995RF79000020 ER PT J AU RAMANAMURTHY, PV BERTSCH, DL DINGUS, BL ESPOSITO, JA FIERRO, JM FICHTEL, CE HUNTER, SD KANBACH, G KNIFFEN, DA LIN, YC LYNE, AG MATTOX, JR MAYERHASSELWANDER, HA MERCK, M MICHELSON, PF VONMONTIGNY, C MUKHERJEE, R NOLAN, PL THOMPSON, DJ AF RAMANAMURTHY, PV BERTSCH, DL DINGUS, BL ESPOSITO, JA FIERRO, JM FICHTEL, CE HUNTER, SD KANBACH, G KNIFFEN, DA LIN, YC LYNE, AG MATTOX, JR MAYERHASSELWANDER, HA MERCK, M MICHELSON, PF VONMONTIGNY, C MUKHERJEE, R NOLAN, PL THOMPSON, DJ TI EGRET DETECTION OF PULSED GAMMA-RADIATION FROM PSR B1951+32 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, OBSERVATIONS; PULSARS, INDIVIDUAL (PSR B1951+32) ID RAPIDLY SPINNING PULSARS; ENERGETIC RADIATION; RAY; NEBULA; CRAB AB We detected a sixth high-energy gamma-ray pulsar, PSR B1951+32, pulsating in gamma rays at E greater than or equal to 100 MeV with the same 39.5 ms periodicity as in radio, using the data obtained during 1991 May to 1994 July by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma Ray Observatory. Although seen only as a weak source amidst the high background of galactic disk emission, the pulsation in high-energy gamma rays is clearly seen. The pulsed radiation has a photon spectral index of -1.74 +/- 0.11. There is no evidence as yet for unpulsed emission from the object. The pulsar appears to have an efficiency of similar to 0.004 for converting its rotational energy loss into gamma rays at E greater than or equal to 100 MeV. C1 STANFORD UNIV,WW HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. MAX PLANCK INST EXTRATERR PHYS,D-85748 GARCHING,GERMANY. HAMPDEN SYDNEY COLL,DEPT PHYS,HAMPDEN SYDNEY,VA 23943. UNIV MANCHESTER,DEPT PHYS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. COMP SCI CORP,COMPTON OBSERV,CTR SCI SUPPORT,GREENBELT,MD 20770. RP RAMANAMURTHY, PV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; OI Thompson, David/0000-0001-5217-9135; Dingus, Brenda/0000-0001-8451-7450 NR 34 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 1995 VL 447 IS 2 BP L109 EP L112 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF790 UT WOS:A1995RF79000012 ER PT J AU MCKENNA, JT AF MCKENNA, JT TI JOINT FLIGHT PROVES SHUTTLE-MIR PLANS SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Article RP MCKENNA, JT (reprint author), LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD JUL 10 PY 1995 VL 143 IS 2 BP 22 EP 23 PG 2 WC Engineering, Aerospace SC Engineering GA RH022 UT WOS:A1995RH02200005 ER PT J AU CHANDRA, S VAROTSOS, CA AF CHANDRA, S VAROTSOS, CA TI RECENT TRENDS OF THE TOTAL COLUMN OZONE - IMPLICATIONS FOR THE MEDITERRANEAN REGION SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT 1st International Symposium on Ozone Depletion and Solar Ultraviolet Radiation - Impacts on Human Health: A Case Study of the Mediterranean Region (1st OSUR) CY APR 09-10, 1994 CL ATHENS, GREECE SP Univ Athens, Russian Acad Sci, Res Ctr Ecol Safety, NASA, Goddard Space Flight Ctr, Dundee Univ, Alfred Wegener Inst Polar & Marine Res, Andreas Sygros Hosp Athens, Photobiol Unit AB The daily ozone column amounts during the 14-year period (1979-1992), which are inferred from measurements made with both the Total Ozone Mapping Spectrometer (TOMS) mounted on board the Nimbus-7 satellite have been used to study longitudinal trends at mid-latitudes. The main findings are: (1) There is a large longitudinal variation of the monthly trend in total ozone over the northern mid-latitudes ranging from 1.5 to 8.5 per cent per year with a large standard error, (2) The trend in the total ozone content over the Mediterranean area varies in a similar way with the zonal average total ozone trend over mid-latitudes. Also, the trend of the total ozone over Athens, Greece, is representative of the whole Mediterranean region and so it is representative of the zonal average total ozone trend over the northern mid-latitudes, and (3) The interannual variability of the amplitude of the annual wave in the total ozone amount over the Mediterranean region compares extremely well with the interannual variability of the total ozone amount over this location. C1 UNIV ATHENS,DEPT APPL PHYS,GR-10680 ATHENS,GREECE. RP CHANDRA, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Varotsos, Costas/H-6257-2013 OI Varotsos, Costas/0000-0001-7215-3610 NR 2 TC 61 Z9 62 U1 0 U2 0 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUL 10 PY 1995 VL 16 IS 10 BP 1765 EP 1769 PG 5 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA RM209 UT WOS:A1995RM20900004 ER PT J AU CRIMINALE, WO JACKSON, TL LASSEIGNE, DG AF CRIMINALE, WO JACKSON, TL LASSEIGNE, DG TI TOWARDS ENHANCING AND DELAYING DISTURBANCES IN FREE SHEAR FLOWS SO JOURNAL OF FLUID MECHANICS LA English DT Article AB The family of shear flows comprising the jet, wake, and the mixing layer are subjected to perturbations in an inviscid incompressible fluid. By modelling the basic mean hows as parallel with piecewise linear variations for the velocities, complete and general solutions to the linearized equations of motion can be obtained in closed form as functions of all space variables and time when posed as an initial-value problem. The results show that there is a continuous spectrum as well as the discrete spectrum that is more familiar in stability theory and therefore there can be both algebraic and exponential growth of disturbances in time. These bases make it feasible to consider control of such flows. To this end, the possibility of enhancing the disturbances in the mixing layer and delaying the onset in the jet and wake is investigated. It is found that growth of perturbations can be delayed to a considerable degree for the jet and the wake but, by comparison, cannot be enhanced in the mixing layer. By using moving coordinates, a method for demonstrating the predominant early and long time behaviour of disturbances in these flows is given for continuous velocity profiles. It is shown that the early time transients are always algebraic whereas the asymptotic limit is that of an exponential normal mode. Numerical treatment of the new governing equations confirm the conclusions reached by use of the piecewise linear basic models. Although not pursued here, feedback mechanisms designed for control of the flow could be devised using the results of this work. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681. OLD DOMINION UNIV,DEPT MATH & STAT,NORFOLK,VA 23529. RP CRIMINALE, WO (reprint author), UNIV WASHINGTON,DEPT APPL MATH,SEATTLE,WA 98195, USA. NR 9 TC 14 Z9 14 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 10 PY 1995 VL 294 BP 283 EP 300 DI 10.1017/S0022112095002898 PG 18 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RM288 UT WOS:A1995RM28800012 ER PT J AU SCHMIDT, GR CHUNG, TJ NADARAJAH, A AF SCHMIDT, GR CHUNG, TJ NADARAJAH, A TI THERMOCAPILLARY FLOW WITH EVAPORATION AND CONDENSATION AT LOW GRAVITY .1. NON-DEFORMING SURFACE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID ZONE CRYSTAL-GROWTH; RECTANGULAR CAVITY; COMBINED BUOYANCY; CONVECTION; STABILITY; INTERFACE; MODEL AB The problem of steady motion and thermal behaviour of a volatile, wetting liquid in an open cavity under low gravity is defined and examined. The domain geometrically approximates a two-phase pore of liquid on a wicking structure surface, and consists of a 1 to 10(2) mu m wide rectangular cavity bounded by a saturated vapour and liquid reservoir on its upper and lower surfaces, respectively. Thermal non-equilibrium and convection are established by symmetrically superheating or subcooling the pore boundaries by similar to 1 K relative to the vapour. Numerical analyses show that although thermocapillary flow competes with interfacial phase change in dictating the circulation and flow structure, it tends to reinforce the convective effects of evaporation and condensation on surface temperature and heat transport. In addition, highly wetting fluids with curved menisci are characterized by greater circulation intensities and dynamic pressure gradients than a flat surface. The magnitude of these gradients suggests that the fixed menisci shapes assumed in this study are unrealistic, and that the influence of convection on surface morphology should be considered. C1 UNIV ALABAMA,DEPT MECH ENGN,HUNTSVILLE,AL 35899. UNIV ALABAMA,DEPT CHEM ENGN,HUNTSVILLE,AL 35899. RP SCHMIDT, GR (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PROPULS LAB,HUNTSVILLE,AL 35812, USA. NR 30 TC 4 Z9 6 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 10 PY 1995 VL 294 BP 323 EP 347 DI 10.1017/S0022112095002916 PG 25 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RM288 UT WOS:A1995RM28800014 ER PT J AU SCHMIDT, GR CHUNG, TJ NADARAJAH, A AF SCHMIDT, GR CHUNG, TJ NADARAJAH, A TI THERMOCAPILLARY HOW WITH EVAPORATION AND CONDENSATION AT LOW GRAVITY .2. DEFORMABLE SURFACE SO JOURNAL OF FLUID MECHANICS LA English DT Article AB The free surface behaviour of a volatile wetting liquid at low gravity is studied using scaling and numerical techniques. An open cavity model, which was applied in part 1 to investigate fluid flow and heat transfer in non-deforming pores, is used to evaluate the influence of convection on surface morphology with length scales and subcooling/superheating limits of 1 less than or equal to D less than or equal to 10(2) mu m and similar to 1 K, respectively. Results show that the menisci shapes of highly wetting fluids are sensitive to thermocapillary flow and to a lesser extent the recoil force associated with evaporation and condensation. With subcooling, thermocapillarity produces a suction about the pore centreline that promotes loss of mechanical equilibrium, while condensation exerts an opposing force that under some conditions offsets this destabilizing influence. With-superheating, thermocapillarity and evaporation act in the same direction and mutually foster; surface stability. All of these trends are magnified by high capillary and Riot numbers, and the stronger circulation intensities associated with small contact angles. These phenomena strongly depend on the thermal and interfacial equilibrium between the liquid and vapour, and have important ramifications for systems designed to maintain a pressure differential across a porous surface. C1 UNIV ALABAMA,DEPT MECH ENGN,HUNTSVILLE,AL 35899. UNIV ALABAMA,DEPT CHEM ENGN,HUNTSVILLE,AL 35899. RP SCHMIDT, GR (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PROPULS LAB,HUNTSVILLE,AL 35812, USA. NR 5 TC 3 Z9 3 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUL 10 PY 1995 VL 294 BP 349 EP 366 DI 10.1017/S0022112095002928 PG 18 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RM288 UT WOS:A1995RM28800015 ER PT J AU WINTSCH, RP CHRISTOFFERSEN, R KRONENBERG, AK AF WINTSCH, RP CHRISTOFFERSEN, R KRONENBERG, AK TI FLUID-ROCK REACTION WEAKENING OF FAULT ZONES SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Review ID SHEAR ZONES; DEFORMATION MECHANISMS; SAN-ANDREAS; REGIONAL METAMORPHISM; ACCRETIONARY PRISMS; HEAT-FLOW; CONTINENTAL LITHOSPHERE; CHEMICAL-CHANGES; NORTH-CAROLINA; MYLONITE ZONE AB The presence of weak phyllosilicates may explain the low shear strengths of fault zones if they define well-developed fabrics. The growth of phyllosilicates is favored in meteoric water-dominated granitic fault systems, where mineral-aqueous fluid equilibria predict that modal phyllosilicate will increase via feldspar replacement reactions. In deeper, more alkaline, rock-dominated regimes, the reactions reverse, and feldspars tend to replace phyllosilicates. In Mg-rich mafic rocks, however, phyllosilicates (chlorite, biotite) can replace stronger framework and chain silicates in both shallower ( several MeV. This class includes radio-quiet AGNs in addition to radio galaxies apparently viewed at large angles with respect to the radio jet axis. The redshifts of objects in the second class, which are associated with AGNs classified as blazars, are as large as z congruent to 2.3, and the range of 100 MeV-5 GeV luminosities, assuming isotropic emission, extends to 10(49) ergs s(-1). The approximate to 20 MeV-30 GeV gamma-ray luminosity often dominates the bolometric luminosity in objects of this class. These sources probably represent AGNs that are observed nearly along the axis of a radio jet. Some AGNs show evidence from the high-energy data for transitional behavior between the two classes. We consider whether the qualitatively different properties of the two gamma-ray classes provide evidence for quasi-isotropic emission from the Seyferts and beamed emission from the blazars. Comparison of the observed redshift and luminosity distributions with model distributions derived from a treatment of the cosmological statistics of isotropic and beamed sources gives, however, inconclusive results. We treat gamma-ray transparency arguments for beaming, avoiding earlier unproven assumptions that X-rays and E > 100 MeV gamma rays originate from the same site. The pair-production optical depth of E > 100 MeV gamma rays interacting with other gamma rays is much less than 1 and does not require beaming, but data from OSSE give evidence for beaming in a few blazars. We generalize to the gamma-ray regime the Elliot-Shapiro relation, which is based on the assumption that AGN radiation is isotropically emitted and that the luminosity is generated by Eddington-limited accretion. Available gamma-ray data do not yet demonstrate a strong conflict with this limit. The generalization of the Eddington-luminosity limit to the Klein-Nishina limit suggests, however, a new type of object that can accrete at luminosities much greater than 10(46) M(8) ergs s(-1) by radiating photons at gamma-ray energies. Here M(8), is the black hole mass in units of 10(8) M(.). Beaming arguments from gamma-ray observations require more observations of blazars, but superluminal observations probably still provide the most compelling evidence for bulk relativistic motion in blazars. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RP USN, RES LAB, EO HULBURT CTR SPACE RES, CODE 7653, WASHINGTON, DC 20375 USA. RI Gehrels, Neil/D-2971-2012 NR 172 TC 101 Z9 104 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP 103 EP 120 DI 10.1086/175859 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900009 ER PT J AU WEAVER, KA ARNAUD, KA MUSHOTZKY, RF AF WEAVER, KA ARNAUD, KA MUSHOTZKY, RF TI A CONFIRMATION OF 2-40 KEV SPECTRAL COMPLEXITY IN SEYFERT-GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, NUCLEI; GALAXIES, SEYFERT; X-RAYS, GALAXIES ID ACTIVE GALACTIC NUCLEI; X-RAY-SPECTRA; COLD MATTER; NGC-4151; VARIABILITY; REFLECTION AB We have reanalyzed 40 spectra of 25 Seyfert and narrow emission line galaxies (NELGs) and one QSO, all of which were obtained during the pointed observations phase (1978 May-1979 January) of the HEAO I A-2 experiment. This investigation was prompted by Ginga results which indicate that Fe Ka lines are common X-ray spectral features of active galactic nuclei (AGNs) and that a high-energy ''bump'' associated with reprocessing of nuclear radiation may be common as well. The HEAO I data, which cover the 2-40 keV energy band, provide a large sample of AGNs with which to test the Ginga results. New analysis techniques are employed which consist of simultaneous fitting of data from both the medium-energy (2-20 keV) and high-energy (3-40 keV) detectors, as well as the subtracting of summed background spectra (up to 230,000 s of data) in order to improve the ratio of signal to noise. These improved techniques have resulted in the detection of Fe K features and/or spectral flattening above similar to 5-10 keV in similar to 75% of the HEAO I sample. This confirms the Ginga result that spectral complexity is common in the X-ray spectra of Seyfert galaxies. We find that strong Fe K lines tend not to be associated with the presence of high-energy flattening, implying that Fe Ka emission is not entirely the result of fluorescence from accretion disks. Our spectral results typically agree with Ginga for overlapping sources for which we have adequate signal-to-noise ratios, although we find a significantly larger reflection component in IC 4329A, NGC 5506, and Mrk 509. For IC 4329A and NGC 5506, a time lag in the response of the reflection component to variability in the intrinsic source flux can explain the presence of more reflection, since the sources were fainter during the HEAO 1 epoch. A similar effect can explain the larger reflection component in Mrk 509, provided the continuum underwent a flux outburst before or during HEAO 1 epoch. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP WEAVER, KA (reprint author), PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,525 DAVEY LAB,UNIVERSITY PK,PA 16802, USA. NR 40 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP 121 EP 138 DI 10.1086/175860 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900010 ER PT J AU WOLFCHASE, GA WALKER, CK AF WOLFCHASE, GA WALKER, CK TI THE DENSE GAS COMPONENT OF OUTFLOWS IN THE MONOCEROS OB1 DARK CLOUD SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, INDIVIDUAL (MONOCEROS OB1); ISM, JETS AND OUTFLOWS; ISM, MOLECULES MOLECULAR PROCESSES; RADIO LINES, ISM ID YOUNG STELLAR OBJECTS; MOLECULAR CLOUD; NGC-2264 AB Wolf-Chase, Walker, & Lada (1995, hereafter WWL) found that most of the CS J = 2-->1 emission in the Mon OB1 dark cloud is concentrated in two regions they refer to as the South Cloud (SCL) and North Cloud (NCL). These regions encompass five of the 10 outflows previously identified in CO by Margulis, Lada, and Snell (1988). The spatial morphologies of the CS J = 5-->4 and CS J = 7-->6 emission regions in the SCL (WWL) are significantly different from those of the CS J = 2-->1 emission. Velocity centroid plots of the CS J = 2-->1 and CS J = 5-->4 emission in the line cores indicate that the upper transition primarily traces dense core material, but the lower transition primarily traces dense outflow material. We have found that the CS J = 2-->1 transition traces a large portion of the dense, low-velocity component of outflows in the Mon OB1 dark cloud. The outflows are identifiable through non-Gaussian, asymmetric wings in the CS J = 2-->1 lines. This outflow component is not identifiable in CO because the gas in the asymmetric CS line wings is moving at velocities which lie within the core of the much broader CO lines. Two of the outflows which were previously classified as monopolar in CO (Margulis et al. 1988) appear bipolar in CS. We find the mass of this component to be about an order of magnitude greater than previous estimates of the low-velocity outflow component. Comparison of the masses derived for the CS outflows to the masses derived by WWL for the total CS emission in the SCL and NCL indicate that at least 20% of the material in the SCL has been entrained in outflows, and approximately 25%-50% of the material in the NCL is associated with a rotating cloud swept up by an outflow. The addition of the low-velocity CS outflow component to previous estimates of outflow energetics implies that multiple generations of outflows need not be required to support this cloud against collapse. Our results neither support nor rule out the existence of fossil outflows in this cloud. A fully sampled, unbiased survey of the cloud is required to search for such outflows. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WOLFCHASE, GA (reprint author), UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721, USA. NR 15 TC 8 Z9 8 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP 244 EP 256 DI 10.1086/175870 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900020 ER PT J AU OWENS, A SCHAEFER, BE SEMBAY, S AF OWENS, A SCHAEFER, BE SEMBAY, S TI DERIVING GAMMA-RAY BURSTER DISTANCES FROM SOFT-X-RAY MEASUREMENTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS ID ABSORPTION; COUNTERPARTS; MODELS; BATSE AB Perhaps the most startling conclusion that can be inferred from observations by the Burst and Transient Source Experiment is that the long-standing question of burster origins may not be answered by gamma-ray measurements alone. The data show that the measured spatial distribution of burst sources is both isotropic and sampled to its characteristic distance-meaning that it is very unlikely that they are related to a Galactic population of neutron stars. When coupled with the lack of an identifiable counterpart at any wavelength or a convincing correlation with any astronomical population, the data have led to a confused proliferation of models. Whereas models tend to be vague on much of the burst details, they can at least be grouped according to a distance scale. We contend that the burster origin problem can best be solved by establishing that scale. Although several techniques have been proposed, we show that this can be easily carried out at soft X-ray wavelengths by measuring the effective column densities of a representative sample of burst spectra. Even if the result does not lead to a unique association with a particular class of object, it will eliminate whole classes of models by providing the first quantitative description of the three-dimensional distribution of burst sources in the universe. In this paper, we demonstrate the feasibility of this technique, both scientifically and technically, and explore actual and perceived problems. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RP UNIV LEICESTER, DEPT PHYS, LEICESTER LE1 7RH, LEICS, ENGLAND. NR 54 TC 3 Z9 3 U1 0 U2 0 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 JUL 1 PY 1995 VL 447 IS 1 BP 279 EP 288 DI 10.1086/175873 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900023 ER PT J AU BAND, DL FORD, LA MATTESON, JL BRIGGS, MS PACIESAS, WS PENDLETON, GN PREECE, RD PALMER, DM TEEGARDEN, BJ SCHAEFER, BE AF BAND, DL FORD, LA MATTESON, JL BRIGGS, MS PACIESAS, WS PENDLETON, GN PREECE, RD PALMER, DM TEEGARDEN, BJ SCHAEFER, BE TI BATSE GAMMA-RAY BURST LINE SEARCH .3. LINE DETECTABILITY SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS; LINE, IDENTIFICATION; METHODS, STATISTICAL ID CYCLOTRON; SPECTRA AB We evaluate the ability of the BATSE spectroscopy detectors to detect the absorption lines observed by Ginga in gamma-ray burst spectra. We find that BATSE can detect the 20.6 keV line in the S1 segment of GB 870303 with a detection probability of similar to 1/4 in nearly normal incident bursts, with the probability dropping off to nearly 0 at a burst angle of 50 degrees; the lines at 19.4 and 38.8 keV in GB 880205 have a high detection probability in BATSE up to burst angles of 75 degrees In addition, we calculate detection probabilities for these two line types as a function of signal-to-noise ratio and burst angle for use in detailed comparisons between BATSE and Ginga. Finally, we consider the probability averaged over the sky of detecting a line feature with the actual array of BATSE detectors on CGRO. C1 UNIV ALABAMA,HUNTSVILLE,AL 35899. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770. RP BAND, DL (reprint author), UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI,LA JOLLA,CA 92093, USA. OI Preece, Robert/0000-0003-1626-7335 NR 23 TC 14 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP 289 EP 301 DI 10.1086/175874 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900024 ER PT J AU PRAVDO, SH ANGELINI, L AF PRAVDO, SH ANGELINI, L TI EMISSION-LINE PRE-MAIN-SEQUENCE STARS AND X-RAY SOURCES IN ORION SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, EMISSION-LINE, BE; STARS, FLARE; STARS, PRE-MAIN-SEQUENCE; X-RAYS, STARS ID T-TAURI STARS; M-DWARFS; STELLAR POPULATION; DARK CLOUD; PROFILES; NEBULA; ABSORPTION; ROTATION; CORONAE; REGION AB We use low-resolution, broadband optical spectroscopy and high-resolution X-ray imaging to continue the study of X-ray sources in the Orion star formation region about 1 degrees south of the Trapezium. We identify 10 new M and K pre-main-sequence (PMS) stars as X-ray sources. At least eight and perhaps all have emission lines. Two stars, V942 and V988 Ori, show evidence for Hot equivalent-width variability. Emission-line PMS (ePMS) stars including both classical (CTTS) and weak-lined T Tauri stars (WTTS) obey the relation between X-ray luminosity and stellar luminosity, L(x) (ergs s(-1)) = 2.2 x 10(8)L*(0.67). The X-ray emission thus tracks the total stellar emission, probably through the dependence of both on stellar surface area, as has been suggested before. Higher mass PMS stars show a similar but flatter dependence of L(x) on L*. For TTS the average value of L(x)/L* = 1.78 x 10(-5). We also detect the integrated X-ray emission from an ensemble of optically fainter stars that may be located deeper in the cluster. The X-ray observations continue to show that the inventory of X-ray sources at a given detection limit stays almost constant over a period of greater than or equal to 10 yr. The probability that a star in this sample flares in X-rays with greater than a factor of similar to 2 increase in average intensity for any similar to 5000 s observation is constrained to be < 10%. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RP CALTECH, JET PROP LAB, MAIL STOP 306-431, PASADENA, CA 91109 USA. NR 53 TC 3 Z9 3 U1 0 U2 0 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 JUL 1 PY 1995 VL 447 IS 1 BP 342 EP 352 DI 10.1086/175878 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900028 ER PT J AU WEILAND, JL SHORE, SN BEAVER, EA LYONS, RW ROSENBLATT, EI AF WEILAND, JL SHORE, SN BEAVER, EA LYONS, RW ROSENBLATT, EI TI GODDARD HIGH-RESOLUTION SPECTROGRAPH OBSERVATIONS OF THE INTERACTING BINARY-SYSTEM W-SERPENTIS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; BINARIES, ECLIPSING; CIRCUMSTELLAR MATTER; STARS, INDIVIDUAL (W SERPENTIS); ULTRAVIOLET, STARS ID BETA-LYRAE; STARS; ALGOL; COMPONENT; MODEL; HOT AB Spectroscopic observations of the interacting binary system W Serpentis have been made at two orbital phases using the Goddard High-Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST). Differences in Si IV 1393, 1403 lambda lambda emission-line strengths and profile shapes observed between the two phases suggest that a hot spot exists where the giant stellar companion has transferred mass to an accretion disk surrounding the mass-gaining component. Moreover, strong absorption features superposed on the Si IV emission lines indicate that the accretion disk is geometrically and optically thick. These absorption features have been modeled to constrain the physical conditions of the disk. C1 INDIANA UNIV,DEPT PHYS & ASTRON,S BEND,IN 46634. UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI,LA JOLLA,CA 92093. RP WEILAND, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEN SCI CORP,CODE 6853,GREENBELT,MD 20771, USA. NR 29 TC 8 Z9 8 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP 401 EP 407 DI 10.1086/175883 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF079 UT WOS:A1995RF07900033 ER PT J AU LANZ, T HEAP, SR HUBENY, I AF LANZ, T HEAP, SR HUBENY, I TI HST/GHRS OBSERVATIONS OF THE BETA-PICTORIS SYSTEM - BASIC PARAMETERS AND THE AGE OF THE SYSTEM SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, EARLY-TYPE; STARS, EVOLUTION; STARS, FUNDAMENTAL PARAMETERS; STARS, INDIVIDUAL (BETA PICTORIS); STARS, PRE-MAIN-SEQUENCE ID CIRCUMSTELLAR DISK; SHELL STARS; PHOTOMETRY; EVOLUTION; CANDIDATE; TERMS; FE/H; MASS AB We have reevaluated the basic parameters and age of the A5 IV-V star, beta Pictoris, making use of new observations obtained by the Goddard High-Resolution Spectrograph aboard the Hubble Space Telescope and using modern methods of atmospheric modeling and spectral synthesis. We derive stellar parameters appropriate to its spectral type (T-eff = 8200 +/- 150 K, log g = 4.25 + 0.1) including a normal (solar) metallicity. When dated by comparison with current evolutionary tracks, we find that (1) the star is apparently ''underluminous''-a situation we attribute to (gray) extinction by the disk-and (2) the star is either a pre-main-sequence (PMS) star nearing the zero-age main sequence (ZAMS), or it is a main-sequence star older than 0.3 Gyr. Given the apparent youth of the disk as inferred from its high density, we judge the PMS interpretation as most likely. RP LANZ, T (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 32 TC 46 Z9 46 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP L41 EP L44 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF081 UT WOS:A1995RF08100011 ER PT J AU VANPARADIJS, J WHITE, N AF VANPARADIJS, J WHITE, N TI THE GALACTIC DISTRIBUTION OF LOW-MASS X-RAY BINARIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXY, KINEMATICS AND DYNAMICS; STARS, BINARIES, CLOSE; STARS, NEUTRON; X-RAYS, GENERAL ID VELOCITY; PULSARS; STAR; SUN AB We have analyzed the Galactic distribution of low-mass X-ray binaries (LMXBs) in which the accreting compact object is a neutron star. The rms value of their distances, z, to the Galactic plane equals similar to 1 kpc. This wide z-distribution cannot be explained by systemic velocities that increased as a result of sudden symmetric mass loss at the formation of the neutron star alone. Kick velocities imparted on the neutron star, following the radio pulsar velocity distribution recently derived by Lyne and Lorimer (1994) can account for the LMXB z-distribution. This distribution is consistent with formation of the neutron stars in LMXBs from direct collapse of a helium star and also from accretion-induced collapse of a white dwarf. The triple-star evolution proposed by Eggleton and Verbunt is not a dominant production mechanism for LMXBs. C1 CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP VANPARADIJS, J (reprint author), UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,KRUISLAAN 403,1098 SJ AMSTERDAM,NETHERLANDS. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 21 TC 62 Z9 62 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1995 VL 447 IS 1 BP L33 EP L36 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF081 UT WOS:A1995RF08100009 ER PT J AU PUN, CSJ KIRSHNER, RP SONNEBORN, G CHALLIS, P NASSIOPOULOS, G ARQUILLA, R CRENSHAW, DM SHRADER, C TEAYS, T CASSATELLA, A GILMOZZI, R TALAVERA, A WAMSTEKER, W AF PUN, CSJ KIRSHNER, RP SONNEBORN, G CHALLIS, P NASSIOPOULOS, G ARQUILLA, R CRENSHAW, DM SHRADER, C TEAYS, T CASSATELLA, A GILMOZZI, R TALAVERA, A WAMSTEKER, W TI ULTRAVIOLET OBSERVATIONS OF SN 1987A WITH THE IUE SATELLITE SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE ULTRAVIOLET, STARS; STARS, INDIVIDUAL (SN 1987A) ID LARGE MAGELLANIC CLOUD; OPTICAL SPECTROPHOTOMETRIC ATLAS; BOLOMETRIC LIGHT-CURVE; SUPERNOVA 1987A; INTERSTELLAR EXTINCTION; UBVRI PHOTOMETRY; CERRO-TOLOLO; NEUTRINO BURST; SPECTRAL-LINES; CCD PHOTOMETRY AB Ultraviolet (lambda: 1150-3300 Angstrom) observations of SN 1987A with the IUE satellite provide a unique data set. Observations started the day after discovery, 1987 February 24 (day 1.6), and a total of 751 spectra were obtained through 1992 June 9 (day 1567). The data have been processed to generate a complete catalog of SN 1987A ultraviolet spectra. The data reduction procedure includes careful line-by-line extraction, removing hits and hot pixels, and, most importantly, a scrupulous subtraction of the contribution from stars near SN 1987A within the IUE aperture. In addition to processing the data, we have also extracted light curves, and combined them with the ground-based optical data and HST observations (day 1278 to 2431) to extend the study in both wavelength and time. The data-processing procedures of our IUE study produce results that are consistent with the HST data where they overlap, but not with the IUE study by Sanz Fernandez de Cordoba (1993) because of its incorrect background subtraction. The IUE data are consistent with the ground-based Walraven VBLUW photometry, while we found that flux scale of the Soviet ASTRON satellite spectroscopic data is low by similar to 15%. The UV flux plummeted during the earliest days of observations because of the drop in the photospheric temperature and the increase in opacity. However, after reaching a minimum of 0.04% on day 44, the UV flux increased by 175 times in its contribution to 7% of the total UVOIR bolometric luminosity at day 800. A revised set of bolometric data has been constructed which includes the contribution of UV from day 1 to day 1352. Studies of the UV colors show that the supernova started to get bluer in UV around the time when dust started to form in the ejecta. Our results are consistent with the possibility that the dust condensed may be metal-rich. C1 NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, GREENBELT, MD 20771 USA. VILSPA, ESA IUE OBSERV, E-28080 MADRID, SPAIN. STOCKHOLM OBSERV, S-13336 SALTSJOBADEN, SWEDEN. SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. UNIV SPACE RES ASSOC, WASHINGTON, DC USA. UNIV CATANIA, CATANIA, ITALY. RP PUN, CSJ (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS, 60 GARDEN ST, CAMBRIDGE, MA 02138 USA. NR 139 TC 56 Z9 57 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 1995 VL 99 IS 1 BP 223 EP 261 DI 10.1086/192185 PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RD575 UT WOS:A1995RD57500009 ER PT J AU CAIRNS, B AF CAIRNS, B TI DIURNAL-VARIATIONS OF CLOUD FROM ISCCP DATA SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT International Minimax Workshop on Asymmetric Change of Daily Temperature Range CY SEP 27-30, 1993 CL COLLEGE PK, MD SP US NOAA, Natl Environm Watch Project, US DOE, Global Change Res Program ID UNITED-STATES AB Information on the diurnal cyle of low, mid and high level cloud amount, for the period December 1984 to November 1990, compiled by the International Cloud Climatology Project (ISCCP), is analyzed using complex empirical orthogonal functions applied to the complex envelope of seasonal variations in the diurnal cycle. It is found that previous results on the diurnal variation of cloud amount, obtained from satellite and station data for more restricted periods and regions than that used here, are verified by the ISCCP data. The early afternoon maximum in low level cloud amount over all the world's continental land masses implies that diurnal variability enhances this cloud type's albedo effect. Conversely the nightime and early morning maxima in mid and high level cloud amount, over much of the globe, enhance their greenhouse effect. Any secular change in the diurnal variability of these cloud types could therefore have a significant effect on the net radiation at the Earth's surface. RP CAIRNS, B (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. OI Cairns, Brian/0000-0002-1980-1022 NR 15 TC 34 Z9 38 U1 0 U2 3 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUL PY 1995 VL 37 IS 1-3 BP 133 EP 146 DI 10.1016/0169-8095(94)00074-N PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RM746 UT WOS:A1995RM74600014 ER PT J AU HANSEN, J SATO, M RUEDY, R AF HANSEN, J SATO, M RUEDY, R TI LONG-TERM CHANGES OF THE DIURNAL TEMPERATURE CYCLE - IMPLICATIONS ABOUT MECHANISMS OF GLOBAL CLIMATE-CHANGE SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT International Minimax Workshop on Asymmetric Change of Daily Temperature Range CY SEP 27-30, 1993 CL COLLEGE PK, MD SP US NOAA, Natl Environm Watch Project, US DOE, Global Change Res Program ID GENERAL CIRCULATION MODEL; AIR-TEMPERATURE; TRENDS AB We use a global climate model to investigate the impact of a wide range of radiative forcing and feedback mechanisms on the diurnal cycle of surface air temperature. This allows us not only to rule out many potential explanations for observed diurnal changes, but to infer fundamental information concerning the nature and location of the principal global climate forcings of this century. We conclude that the observed changes of the diurnal cycle result neither from natural climate variability nor a globally-distributed forcing, but rather they require the combination of a (negative) radiative forcing located primarily over continental regions together with the known globally-distributed forcing due to anthropogenic greenhouse gases, Tropospheric aerosols can account for part of the continentally-located forcing, but alone they do not damp the diurnal cycle as observed. Only an increase of continental cloud cover, possibly a consequence of anthropogenic aerosols, can damp the diurnal cycle by an amount comparable to observations. A corollary of these results is quantitative confirmation of the widely held suspicion that anthropogenic greenhouse gas warming has been substantially counterbalanced by a forced cooling. Under the assumption that the cloud change is sulfate driven, a further implication is that the net rate of global warming is likely to increase substantially in coming years. We note that, on the long run, the daily maximum temperature will increase by an amount not much less than the increase of the mean temperature. RP HANSEN, J (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 37 TC 83 Z9 85 U1 0 U2 4 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUL PY 1995 VL 37 IS 1-3 BP 175 EP 209 DI 10.1016/0169-8095(94)00077-Q PG 35 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RM746 UT WOS:A1995RM74600017 ER PT J AU ZINN, HP KOWALSKI, AD AF ZINN, HP KOWALSKI, AD TI AN EFFICIENT PBL MODEL FOR GLOBAL CIRCULATION MODELS - DESIGN AND VALIDATION SO BOUNDARY-LAYER METEOROLOGY LA English DT Article ID PLANETARY BOUNDARY-LAYER; SIMILARITY FUNCTIONS AB An efficient planetary boundary layer (PBL) model is developed and validated with empirical data for applications in general circulation models (GCMs). The purpose of this PBL model is to establish the turbulent surface fluxes as a function of the principal external PBL parameters in a numerically efficient way. It consists of a surface layer and a mixed layer matched together with the conditions of constant momentum and heat flux at the interface. An algebraic solution to the mean momentum equations describes the mixed-layer velocity profile and thus determines the surface wind vector. The velocity profile is globally valid by incorporating the effect of variable Coriolis force without becoming singular at the equator. Turbulent diffusion depends on atmospheric stability and is modeled in the surface layer by a drag law and with first-order closure in the mixed layer. Radiative cooling in the stably stratified PBL is considered in a simple manner. The coupled system is solved by an iterative method. In order to preserve the computational efficiency of the large-scale model, the PBL model is implemented into the GISS GCM by means of look-up tables with the bulk PBL Richardson number, PBL depth, neutral drag coefficient, and latitude as independent variables. A validation of the PBL model with observed data in the form of Rossby number similarity theory shows that the internal feedback mechanisms are represented correctly. The model, however, underpredicted the sensible heat-flux.A subsequent correction in the turbulence parameterization yields better agreement with the empirical data. The behavior of the principal internal PBL quantities is presented for a range of thermal stabilities and latitudes. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP ZINN, HP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 24 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD JUL PY 1995 VL 75 IS 1-2 BP 25 EP 59 DI 10.1007/BF00721043 PG 35 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RV039 UT WOS:A1995RV03900002 ER PT J AU SCHMALZER, PA AF SCHMALZER, PA TI BIODIVERSITY OF SALINE AND BRACKISH MARSHES OF THE INDIAN-RIVER LAGOON - HISTORIC AND CURRENT PATTERNS SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT Biodiversity of the Indian River Lagoon Conference CY FEB 15-16, 1994 CL HARBOR BRANCH OCEANOG OMST, FT PIERCE, FL SP Indian River Lagoon, Natl Estuary Program HO HARBOR BRANCH OCEANOG OMST ID FLORIDA; FIRE AB The Indian River Lagoon (IRL) crosses a zone of climatic transition. Historically, marshes dominated saline and brackish environments in the north of the lagoon, while mangroves were dominant to the south. Periodic freezes limited mangrove distribution and abundance. A unique feature of most IRL marshes was seasonal and wind-driven tidal inundation rather than daily tidal fluctuations; near inlets, tidally influenced marshes occurred. Distribution of marsh communities was influenced by hydrology, salinity, soil characteristics, and fire, as well as periodic freezes. Major marsh community types included cabbage palm (Sabal palmetto) savanna, sand cordgrass (Spartina bakeri) marsh, black rush (Juncus roemerianus) marsh, saltgrass marsh (Distichlis spicata, Paspalum distichum), and mixed halophyte (Batis maritima, Salicornia virginica) marsh. Mud hats occupied significant areas. Black (Avicennia germinans) and white (Languncularia racemosa) mangroves occurred in some areas in open to dense stands associated with saltgrasses and mixed halophytes. Red mangroves (Rhizophora mangle) apparently occurred as scattered individuals fringing the lagoon. Many of these communities were marked by a few dominant species and relatively low within-community plant species diversity. The resulting landscape pattern was complex and diverse. Marshes of the Indian River Lagoon have been greatly modified since the 1940s. Impoundment or ditching for mosquito control has affected most areas. Much of the low marsh was replaced by open water or by extensive cattail (Typha cf. domingensis) marshes. Loss of connection with the uplands and changed hydrology probably reduced fire frequency and intensity in the high marshes, favoring invasion by wetland shrubs (Salix caroliniana, Myrica cerifera, Baccharis spp.) and the exotic Brazilian pepper (Schinus terebinthifolius). Other impacts to marshes include dredging and filling and nutrient enrichment. Dominant and characteristic plant species of these saline and brackish marshes are widespread throughout the Indian River Lagoon. Few rare plants are associated with Indian River Lagoon marshes. Despite significant modifications, marsh plant species have not been lost from the region, but community and landscape patterns have been greatly modified and ecosystem processes altered. Vertebrates dependent on these marshes have not all faired as well, as evidenced by the extinction of the Dusky Seaside Sparrow (Ammodramus maritimus nigrescens) that depended on marshes of the Indian River Lagoon and the St. Johns River. RP SCHMALZER, PA (reprint author), NASA,BIOMED OPERAT & RES OFF,MAIL CODE DYN-2,KENNEDY SPACE CTR,FL 32899, USA. NR 67 TC 18 Z9 19 U1 7 U2 21 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 1995 VL 57 IS 1 BP 37 EP 48 PG 12 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA RH265 UT WOS:A1995RH26500006 ER PT J AU PRABHAKARA, C NUCCIARONE, JJ YOO, JM AF PRABHAKARA, C NUCCIARONE, JJ YOO, JM TI EXAMINATION OF GLOBAL ATMOSPHERIC-TEMPERATURE MONITORING WITH SATELLITE MICROWAVE MEASUREMENTS .1. THEORETICAL CONSIDERATIONS SO CLIMATIC CHANGE LA English DT Article ID RAINFALL; WATER; OCEAN AB In recent studies (Spencer and Christy, 1990; and Spencer et al., 1990) it is suggested that observations at 53.74 GHz made by the Microwave Sounding Unit (MSU), flown on NOAA operational weather satellites, can yield a precise estimate of global mean temperature and its change as a function of time. Hansen and Wilson (1993) question their interpretation of temporal changes on the grounds that the microwave observations could be influenced by the opacity of the variable constituents in the atmosphere. This issue has broad interest because of the importance of detection of global climatic change. In order to help resolve this issue, in this study we utilize a radiative transfer model to simulate: (a) the observations of MSU Channel 1 (Ch. 1) at 50.3 GHz, in the weakly absorbing region of the 60 GHz molecular oxygen absorption band; and (b) the observations of MSU Channel 2 (Ch. 2) at 53.74 GHz, in the moderately strong absorption region of the same band. This radiative transfer model includes extinction due to clouds and rain in addition to absorption due to molecular oxygen and water vapor. The model simulations show that, over the oceans, extinction due to rain and clouds in Ch. 1 causes an increase in brightness temperature, while in Ch. 2 it causes a decrease. Over the land, however, both Ch. 1 and Ch. 2 show a decrease in brightness temperature due to rain and cloud extinction. These theoretical results are consistent with simultaneous observations in Ch. 1 and Ch. 2 made by MSU. Based on theory and observations we infer that a substantial number of the MSU observations at 53.74 GHz used by Spencer et al. contain rain and cloud contamination. As a result, their MSU derived global mean temperatures and long term trend is questionable. C1 HUGHES STX CORP,GREENBELT,MD 20770. EWHA WOMANS UNIV,SEOUL 120750,SOUTH KOREA. RP PRABHAKARA, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 913,GREENBELT,MD 20771, USA. NR 16 TC 14 Z9 14 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUL PY 1995 VL 30 IS 3 BP 349 EP 366 DI 10.1007/BF01091931 PG 18 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RH590 UT WOS:A1995RH59000006 ER PT J AU KU, JC GRIFFIN, DW GREENBERG, PS ROMA, J AF KU, JC GRIFFIN, DW GREENBERG, PS ROMA, J TI BUOYANCY-INDUCED DIFFERENCES IN SOOT MORPHOLOGY SO COMBUSTION AND FLAME LA English DT Note ID DIFFUSION FLAMES; PARTICLES C1 WAYNE STATE UNIV,DEPT MECH ENGN,DETROIT,MI 48202. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,DEPT ELECT ENGN & APPL PHYS,CLEVELAND,OH 44106. NR 14 TC 21 Z9 22 U1 1 U2 1 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUL PY 1995 VL 102 IS 1-2 BP 216 EP 218 DI 10.1016/0010-2180(95)00108-I PG 3 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA RG615 UT WOS:A1995RG61500019 ER PT J AU STEMPLE, AD RHIM, JW KIM, YH AF STEMPLE, AD RHIM, JW KIM, YH TI VIBRATION ANALYSIS OF ROTATING COMPOSITE BEAMS USING A FINITE-ELEMENT MODEL WITH WARPING DEGREES OF FREEDOM SO COMPUTATIONAL MECHANICS LA English DT Article AB A finite element beam formulation that properly takes into account the warping of the cross-sections has been extended to the free vibration analysis of rotating and non-rotating composite beams. The formulation allows transverse shear deformation and the warping effects are incorporated by superimposing warping displacements that are parallel to the beam axis in the deformed configuration. For modeling of thin and moderately thick walled sections, the strain is assumed to be linear through the wall thickness. Numerical tests were conducted to calculate the natural frequencies of cantilever composite beams with various ply layups. Correlations of the calculated natural frequencies with experimentally measured values demonstrate the validity of the present approach. Although only rectangular solid and box beams were considered for numerical tests, the formulation allows modeling of beams with complicated cross-sections, tapers, pretwists and arbitrary planforms. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681. MCDONNELL DOUGLAS CORP,ST LOUIS,MO 63166. UNIV MARYLAND,DEPT AEROSP ENGN,COLLEGE PK,MD 20742. NR 17 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0178-7675 J9 COMPUT MECH JI Comput. Mech. PD JUL PY 1995 VL 16 IS 4 BP 258 EP 265 PG 8 WC Mathematics, Interdisciplinary Applications; Mechanics SC Mathematics; Mechanics GA RM543 UT WOS:A1995RM54300006 ER PT J AU COLBAUGH, R GLASS, K SERAJI, H AF COLBAUGH, R GLASS, K SERAJI, H TI ROBUST ADAPTIVE-CONTROL OF LAGRANGIAN SYSTEMS SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article DE ADAPTIVE CONTROL; LAGRANGIAN SYSTEM CONTROL; LYAPUNOV METHODS; ROBOT CONTROL ID ROBOTIC MANIPULATORS; CONFIGURATION CONTROL; MECHANICAL SYSTEMS; REDUNDANT ROBOTS; ATTITUDE-CONTROL; STABILIZATION; SPACECRAFT; MOTION AB This paper presents a new adaptive scheme for the motion control of an important class of Lagrangian systems. The proposed controller does not require knowledge of either the structure or the parameter values of the system dynamic model. As a consequence, the control scheme is very general and computationally efficient, and is implementable with a wide variety of systems. It is shown that the control strategy is globally stable in the presence of bounded disturbances, and that in the absence of disturbances the ultimate bound on the size of the trajectory tracking errors can be made arbitrarily small. The capabilities of the proposed control scheme are illustrated through computer simulations and experiments involving industrial robots. These studies demonstrate that the controller provides a simple and effective means of obtaining high performance trajectory tracking. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP COLBAUGH, R (reprint author), NEW MEXICO STATE UNIV,DEPT MECH ENGN,DEPT 3450,BOX 30001,LAS CRUCES,NM 88003, USA. NR 41 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PD JUL PY 1995 VL 21 IS 4 BP 229 EP 241 DI 10.1016/0045-7906(95)00008-I PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA RH133 UT WOS:A1995RH13300002 ER PT J AU KAISER, MK HECHT, H AF KAISER, MK HECHT, H TI THE PERCEPTUAL SYSTEM - A PHILOSOPHICAL AND PSYCHOLOGICAL PERSPECTIVE - BENZEEV,A SO CONTEMPORARY PSYCHOLOGY LA English DT Book Review C1 NASA,AMES RES CTR,NATL RES COUNCIL,MOFFETT FIELD,CA 94035. RP KAISER, MK (reprint author), NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS RES,MOFFETT FIELD,CA 94035, USA. RI Hecht, Heiko/H-3106-2011 NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 SN 0010-7549 J9 CONTEMP PSYCHOL JI Comtemp. Psychol. PD JUL PY 1995 VL 40 IS 7 BP 653 EP 655 PG 3 WC Psychology, Multidisciplinary SC Psychology GA RG832 UT WOS:A1995RG83200015 ER PT J AU KAISER, MK HECHT, H AF KAISER, MK HECHT, H TI FOUNDATIONS OF PERCEPTUAL THEORY - MASIN,SC SO CONTEMPORARY PSYCHOLOGY LA English DT Book Review C1 NASA,AMES RES CTR,NATL RES COUNCIL,MOFFETT FIELD,CA 94035. RP KAISER, MK (reprint author), NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS RES,MOFFETT FIELD,CA 94035, USA. RI Hecht, Heiko/H-3106-2011 NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 SN 0010-7549 J9 CONTEMP PSYCHOL JI Comtemp. Psychol. PD JUL PY 1995 VL 40 IS 7 BP 653 EP 655 PG 3 WC Psychology, Multidisciplinary SC Psychology GA RG832 UT WOS:A1995RG83200014 ER PT J AU WANG, SG SHIEH, LS SUNKEL, JW AF WANG, SG SHIEH, LS SUNKEL, JW TI ROBUST OPTIMAL POLE-CLUSTERING IN A VERTICAL STRIP AND DISTURBANCE REJECTION FOR UNCERTAIN LAGRANGE SYSTEMS SO DYNAMICS AND CONTROL LA English DT Article ID LINEAR-SYSTEMS; STABILIZATION AB This paper presents an approach to design a state-feedback robust control law for uncertain Lagrange's systems such that the designed closed-loop systems have the properties of robust pole-clustering within a vertical strip and disturbance rejection with an H(infinity)-norm constraint. This approach is based on solving an algebraic Riccati equation with the adjustable scalars and prespecified parameters. The uncertainties considered include both unstructured and structured uncertainties in the system and the input matrices. Also, a constraint is established to verify that the proposed robust LQRs preserve H-2 optimality with respect to a specific quadratic cost function. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV AVION SYST,HOUSTON,TX 77058. UNIV HOUSTON,DEPT ELECT & COMP ENGN,HOUSTON,TX 77204. RP WANG, SG (reprint author), PRAIRIE VIEW A&M UNIV,TEXAS A&M UNIV SYST,DEPT MECH ENGN,PRAIRIE VIEW,TX 77446, USA. NR 13 TC 12 Z9 12 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0925-4668 J9 DYNAM CONTROL JI Dynam. Control PD JUL PY 1995 VL 5 IS 3 BP 295 EP 312 DI 10.1007/BF01968679 PG 18 WC Automation & Control Systems; Engineering, Mechanical SC Automation & Control Systems; Engineering GA RD465 UT WOS:A1995RD46500005 ER PT J AU HAMPTON, RW NELSON, DV AF HAMPTON, RW NELSON, DV TI EFFECT OF SURFACE CONDITION AND PRIOR PLASTIC-DEFORMATION ON X-RAY EFFECTIVE ELASTIC PARAMETERS IN A STEEL AND ITS WELD SO EXPERIMENTAL TECHNIQUES LA English DT Article C1 STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. RP HAMPTON, RW (reprint author), NASA,AMES RES CTR,TEST ENGN & ANAL BRANCH,MOFFETT FIELD,CA 94035, USA. NR 5 TC 2 Z9 2 U1 0 U2 1 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0732-8818 J9 EXP TECHNIQUES JI Exp. Tech. PD JUL-AUG PY 1995 VL 19 IS 4 BP 25 EP 28 PG 4 WC Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Engineering; Mechanics; Materials Science GA RL814 UT WOS:A1995RL81400005 ER PT J AU ABLE, KW FAHAY, MP SHEPHERD, GR AF ABLE, KW FAHAY, MP SHEPHERD, GR TI EARLY-LIFE HISTORY OF BLACK-SEA BASS, CENTROPRISTIS-STRIATA IN THE MID-ATLANTIC BIGHT AND A NEW-JERSEY ESTUARY SO FISHERY BULLETIN LA English DT Article ID POPULATIONS; BAY AB This study focuses on composite field collections and in situ observations from the mid-Atlantic Eight continental shelf and a New Jersey estuary in order to elucidate aspects of the early life history of age 0+ black sea bass, Centropristis striata. Spawning in the mid-Atlantic Eight is prolonged (April through November, with a peak between June and September) and is most intense in the southern portion of this range. Between 1977 and 1987, larvae were collected between Cape Hatteras, North Carolina, and Long Island, New York. In New Jersey coastal waters larvae first appear in July but can occur into November. Recently settled individuals (15-24 mm total length [TL]) were collected at an inner continental shelf site and an adjacent estuary from July through October. By fall, fishes from these areas were 18-91 mm TL, and many had moved offshore from New Jersey estuarine waters and other estuaries to inner continental shelf waters between southern Massachusetts and Cape Hatteras. Subsequently, they continued to move offshore and during their first winter, they were concentrated near the shelf or slope break in the southern portion of the mid-Atlantic Eight. Some age 0+ individuals moved back into New Jersey estuaries in early spring, at sizes approximating those of the previous fall (50-96 mm TL). Thus, black sea bass reach relatively small sizes after 12 months of growth partly because little or no growth occurs during their first winter. This year class reached sizes of 78-175 mm TL by midsummer and 134-225 mm TL by the following fall. During summer, benthic juveniles were collected or observed primarily in a variety of structured habitats. On the inner continental shelf they were found among accumulations of surfclam Spisula solidissima valves or among smaller pieces of shell, and occasionally in burrows in exposed clay. While in the estuary, they were collected from areas with a variety of structured habitats, such as shell accumulations in marsh creeks and peat banks. The data suggest that during their first summer, black sea bass have similar densities and growth rates in estuarine and inner continental shelf habitats, and thus both areas serve as nurseries. C1 SANDY HOOK LAB,NE FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,HIGHLANDS,NJ 07732. WOODS HOLE LAB,NE FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,WOODS HOLE,MA 02543. RP ABLE, KW (reprint author), RUTGERS STATE UNIV,INST MARINE & COASTAL SCI,MARINE FIELD STN,800 GREAT BAY BLVD,TUCKERTON,NJ 08087, USA. NR 58 TC 21 Z9 24 U1 3 U2 8 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1995 VL 93 IS 3 BP 429 EP 445 PG 17 WC Fisheries SC Fisheries GA RG190 UT WOS:A1995RG19000001 ER PT J AU RENAUD, ML CARPENTER, JA WILLIAMS, JA MANZELLATIRPAK, SA AF RENAUD, ML CARPENTER, JA WILLIAMS, JA MANZELLATIRPAK, SA TI ACTIVITIES OF JUVENILE GREEN TURTLES, CHELONIA-MYDAS, AT A JETTIED PASS IN SOUTH TEXAS SO FISHERY BULLETIN LA English DT Note ID SEA TURTLES C1 USA,CORPS ENGINEERS,GALVESTON,TX 77553. RP RENAUD, ML (reprint author), NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,GALVESTON LAB,4700 AVE U,GALVESTON,TX 77551, USA. NR 31 TC 25 Z9 26 U1 1 U2 6 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1995 VL 93 IS 3 BP 586 EP 593 PG 8 WC Fisheries SC Fisheries GA RG190 UT WOS:A1995RG19000015 ER PT J AU PETERS, MT SHAFFER, EE BURNETT, DS KIM, SS AF PETERS, MT SHAFFER, EE BURNETT, DS KIM, SS TI MAGNESIUM AND TITANIUM PARTITIONING BETWEEN ANORTHITE AND TYPE-B CAI LIQUID - DEPENDENCE ON OXYGEN FUGACITY AND LIQUID COMPOSITION SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID AL-RICH INCLUSIONS; CRYSTALLIZATION SEQUENCES; CARBONACEOUS CHONDRITES; REFRACTORY INCLUSION; ALLENDE; COEFFICIENTS; PLAGIOCLASE; MELILITE; MELTS; TEMPERATURE AB Experiments were conducted in air and at low oxygen fugacity (f(o2)) to evaluate Mg and Ti partitioning between anorthite and liquid (D-Mg and D-Ti) in a synthetic composition similar to that of a Type B Ca, Al-rich inclusion (CAI). The starting material showed a range of compositions, which allowed assessment of the composition dependence of D-Mg and D-Ti in this system. Additional experiments using a homogeneous split of the same material investigated the effect of oxygen fugacity on the partitioning of Ti3+ and Ti4+ between anorthite and liquid. The low f(o2) charges were purple, consistent with the presence of significant amounts of Ti3+. This was verified by electron spin resonance (ESR) spectra, and quantitative estimates of Ti3+ contents were obtained using ESR. The Ti and Mg partition coefficients in the air run using the homogeneous starting material are similar (0.034 and 0.036, respectively) and consistent with those determined in other studies. However, D-Ti at low f(o2) is slightly greater than D-Ti in the air experiments. Using Ti3+/total Ti from the ESR measurements, D-Ti3+ is calculated to be about 0.040. The range of compositions reveal a clustering of D-Mg and D-Ti within charges, but a wide range of Ds between charges of different composition. A well-defined inverse correlation exists between D-Mg and D-Ti. This variation is not due to temperature-dependence, but is instead due to the dependence of D-Mg and D-Ti on liquid composition (Si and Al in particular). D-Mg correlates positively with Si content and negatively with Al content, while D-Ti Shows the opposite correlations. The results of these experiments have interesting implications for the petrogenesis of Type B CAIs and for substitution mechanisms of Mg, Ti4+, and Ti3+ into anorthite. Crystallization models for Type B CAIs permit certain predictions concerning trace element systematics in plagioclase. The Mg and Ti systematics are best explained by a fractional crystallization model where plagioclase crystallizes very late (>95% crystallization), and D-Ti3+ is equal to D-Ti4+. The results from our experiments support this model for the relative partitioning of Ti4+ and Ti3+ between plagioclase and liquid. In addition, the dependence of D-Mg and D-Ti on the Si content of a Type B CAI liquid helps explain systematics expected during late-stage crystallization of plagioclase. The composition dependence of D-Mg and D-Ti also allows assessment of substitution mechanisms in anorthite using a crystallization reaction approach. Using these methods, a plausible mechanism for Mg involves substitution for tetrahedral Al by the reaction Mg2+ + Si4+ = 2Al(3+) consistent with that proposed by previous workers. The systematics are also consistent with Ti4+ and Ti3+ substitution for tetrahedral Si4+ by the reactions 2Al(3+) + Ti4+ = Ca2+ + 2Si4(+) and Al3+ + Ti3+ = Ca2+ +Si4+, respectively. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP PETERS, MT (reprint author), CALTECH,DEPT GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. NR 44 TC 13 Z9 13 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUL PY 1995 VL 59 IS 13 BP 2785 EP 2796 DI 10.1016/0016-7037(95)00173-W PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL234 UT WOS:A1995RL23400012 ER PT J AU THOMAS, KL BLANFORD, GE CLEMETT, SJ FLYNN, GJ KELLER, LP KLOCK, W MAECHLING, CR MCKAY, DS MESSENGER, S NIER, AO SCHLUTTER, DJ SUTTON, SR WARREN, JL ZARE, RN AF THOMAS, KL BLANFORD, GE CLEMETT, SJ FLYNN, GJ KELLER, LP KLOCK, W MAECHLING, CR MCKAY, DS MESSENGER, S NIER, AO SCHLUTTER, DJ SUTTON, SR WARREN, JL ZARE, RN TI AN ASTEROIDAL BRECCIA - THE ANATOMY OF A CLUSTER IDP SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID INTERPLANETARY DUST PARTICLES; UNEQUILIBRATED ORDINARY CHONDRITES; MAJOR ELEMENT COMPOSITION; MURCHISON METEORITE; ISOTOPIC VARIATIONS; SIZE DISTRIBUTIONS; HELIUM; CARBON; ACIDS; MICROMETEORITES AB We report results of a consortium study of a large interplanetary dust particle known as cluster 1,2008#5. This cluster is composed of fifty-three fragments (>5 mu m in diameter) and several hundred fines (<5 mu m in diameter). Fragments and some fines were characterized using a variety of chemical and mineralogical techniques including: energy dispersive X-ray analyses for bulk chemical compositions for elements carbon through nickel, transmission electron microscopy for mineralogy, noble gas measurements, synchrotron X-ray fluorescence for trace element abundances, isotopic abundances using an ion probe, trace organic abundances, and reflectance spectroscopy. Our results show that cluster L2008#5 displays strong chemical and mineralogical heterogeneity on a size scale of the individual fragments (similar to 10 mu m in diameter). Despite the strong heterogeneity, we believe that nearly all of the analyzed fragments were originally part of the same cluster in space. Several methods were used to estimate the degree of heating that this cluster experienced. Variations in the inferred peak temperatures experienced by different fragments suggest that a thermal gradient was maintained. The cluster as a whole was not strongly heated; it is estimated to have a low earth-encounter velocity which is consistent with origin from an object in an asteroidal orbit rather than from a comet, which would most likely have a high entry velocity. Our conclusions show that cluster 1,2008#5 consists of a chemically and mineralogically diverse mixture of fragments. We believe that cluster 1,2008#5 represents a heterogeneous breccia and that it was most likely derived from an object in an asteroidal orbit. We also present an important cautionary note for attempts to interpret individual, small-sized 10-15 mu m IDPs as representative of parent bodies. It is not unique that individual building blocks of IDPs, such as discrete olivine, pyroxene, sulfide grains, regions of carbonaceous material, and other noncrystalline material, are found in several fragments; however, it is unique that these building blocks are combined in various proportions in related IDPs from one large cluster particle. C1 UNIV HOUSTON CLEAR LAKE, HOUSTON, TX 77058 USA. STANFORD UNIV, DEPT CHEM, STANFORD, CA 94305 USA. SUNY COLL PLATTSBURGH, DEPT PHYS, PLATTSBURGH, NY 12901 USA. MVA INC, NORCROSS, GA 30093 USA. UNIV MUNSTER, INST PLANETOL, W-4400 MUNSTER, GERMANY. NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. WASHINGTON UNIV, MCDONNELL CTR SPACE SCI, DEPT PHYS, ST LOUIS, MO 63130 USA. UNIV MINNESOTA, SCH PHYS & ASTRON, MINNEAPOLIS, MN 55455 USA. UNIV CHICAGO, DEPT GEOPHYS SCI, CHICAGO, IL 60637 USA. RP THOMAS, KL (reprint author), LOCKHEED ENGN & SCI CO, 2400 NASA RD 1, HOUSTON, TX 77058 USA. RI Zare, Richard/A-8410-2009 NR 60 TC 48 Z9 48 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUL PY 1995 VL 59 IS 13 BP 2797 EP 2815 DI 10.1016/0016-7037(95)00174-X PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL234 UT WOS:A1995RL23400013 ER PT J AU NYQUIST, LE WIESMANN, H BANSAL, B SHIH, CY KEITH, JE HARPER, CL AF NYQUIST, LE WIESMANN, H BANSAL, B SHIH, CY KEITH, JE HARPER, CL TI SM-146-ND-142 FORMATION INTERVAL FOR THE LUNAR MANTLE SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID MARE BASALTS; SM-ND; RB-SR; AGE; EVOLUTION; SAMPLES; DIFFERENTIATION; ND-142; SYSTEMATICS; ABUNDANCES AB Now-extinct Sm-146 (t(1/2) = 103 Ma) was present in the early solar system, and lunar basalts might be expected to have inherited small anomalies in Nd-142 abundances from mantle sources with variable Sm/Nd ratios established during the early global differentiation of the Moon. Nd-142/Nd-144 ratios were measured for several lunar basalts, and values of epsilon(Nd)(142), (deviations from terrestrial Nd-142/Nd-144 in parts in 10(4)) calculated for them. The epsilon(Nd)(142) values show very small variations attributable to Sm-146 decay. Neutron capture near the lunar surface also modified both the samarium and neodymium isotopic compositions of the basalt samples. The calculated neutron fluences range from similar to 0 to similar to 7.8 X 10(16) n/cm(2). Both thermal and epithermal neutron fluences were calculated from the Sm isotopic compositions of the basalts and used to correct the epsilon(Nd)(142) values for neutron capture by neodymium. Well-resolved radiogenic enrichments epsilon(Nd)(142) = + 0.28 +/- 0.11 and + 0.17 +/- 0.08 (2 sigma), respectively, were measured for lunar meteorite Asuka 881757 and Apollo 17 basalt 74255, respectively, for which the neutron fluences were nil. Basalts 70135 and 75075, which were exposed to small, measureable neutron fluences of similar to 2.5 x 10(15) and similar to 7.7 x 10(15) n/Cm-2, respectively, have neutron-corrected epsilon(Nd)(142) values of + 0.25 +/- 0.15 and + 0.29 +/- 0.11, respectively. The average value of radiogenic epsilon(Nd)(142) for the three high-Ti basalts from Apollo 17 is + 0.22 +/- 0.06. Neutron capture effects were greater for the other basalts, but can be corrected using the measured neutron fluences derived from the samarium isotopic data. The neutron-corrected epsilon(Nd)(142) = + 0.19 +/- 0.20 for Apollo 12 ilmenite basalt 12056, consistent with its derivation from a highly depleted mantle source also. Three low-Ti basalts from Apollo 12 and Apollo 15 (12038, 15076, 15555), have neutron corrected epsilon(Nd)(142) which are not resolved from zero, and average + 0.04 +/- 0.06. A fourth low-Ti basalt, 12039, has neutron-corrected epsilon(Nd)(142) = +/- 0.25 Nd +/- 0.12, but is subject to the largest neutron correction of similar to 0.32 epsilon-units. KREEP basalt 14078 was exposed to only a small neutron fluence of similar to 6.4 X 10(15) n/cm(2), and has a small deficit of Nd-142, corresponding to epsilon(Nd)(142) = -0.11 +/- 0.08. The average neutron-corrected epsilon(Nd)(142) of three KREEP basalts is -0.05 +/- 0.04. The epsilon(Nd)(142) values of the basalts correlate with Sm-147/Nd-144 values for their source regions as calculated from their ages and initial epsilon(NdCHUR,I)(143) values. Sm-147/Nd-143 and Sm-146-Nd-142 systematics were combined in a three-stage model yielding an isochron equation for the lunar mantle formation interval, which was calculated to be 238(-40)(+56) Ma (2 sigma). Sm/Nd ratios for the source regions also are derived from the model and compare favorably with values from conventional geochemical models of mare basalt petrogenesis. If the Moon were formed by impact of a large, Mars-sized planetesimal with the Earth, the impact was early enough that the lunar mantle cooled to neodymium isotopic closure by similar to 4. 32 Ga ago. The bulk lunar epsilon(Moon)(142) evaluated from the mantle isochron at (Sm-147/Nd-144)(CHUR) = 0.1967 is -0.01 +/- 0.03 (2 sigma), consistent with derivation of lunar and terrestrial neodymium from a common reservoir. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77258. HARVARD UNIV,DEPT EARTH & PLANETARY SCI,CAMBRIDGE,MA 02138. RP NYQUIST, LE (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058, USA. NR 78 TC 101 Z9 106 U1 2 U2 17 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUL PY 1995 VL 59 IS 13 BP 2817 EP 2837 DI 10.1016/0016-7037(95)00175-Y PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL234 UT WOS:A1995RL23400014 ER PT J AU DESSLER, AE CONSIDINE, DB MORRIS, GA SCHOEBERL, MR RUSSELL, JM ROCHE, AE KUMER, JB MERGENTHALER, JL WATERS, JW GILLE, JC YUE, GK AF DESSLER, AE CONSIDINE, DB MORRIS, GA SCHOEBERL, MR RUSSELL, JM ROCHE, AE KUMER, JB MERGENTHALER, JL WATERS, JW GILLE, JC YUE, GK TI CORRELATED OBSERVATIONS OF HCL AND CLONO2 FROM UARS AND IMPLICATIONS FOR STRATOSPHERIC CHLORINE PARTITIONING SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HETEROGENEOUS CHEMISTRY; CLOUD AB We present the first near-global set of correlated measurements of stratospheric HCl and ClONO2 concentrations. These data, obtained from the Upper Atmosphere Research Satellite (UARS) between August 1992 and March 1993, are analyzed using the Goddard trajectory mapping technique. These data indicate that, between 20 and 30 km altitude and 60 degrees N to 60 degrees S latitude, total inorganic chlorine (Cry) is fairly evenly distributed between ClONO2 and HCl, with HCl the slightly more dominant reservoir. The sum of UARS measurements of HCl and nighttime ClONO2, which approximates Cry at these; altitudes, closely agrees with Cry derived from a tracer-Cly relation originally derived from aircraft data, increasing confidence in the UARS data. Comparisons between these data and two-dimensional model results suggest that models underpredict ClONO2 (overpredict HCl) near 20 km and overpredict ClONO2 (underpredict KCl) near 30 km, although the 20-km underprediction is not as large as analyses of aircraft measurements have indicated. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP DESSLER, AE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 15 TC 40 Z9 40 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1721 EP 1724 DI 10.1029/95GL01593 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900022 ER PT J AU TABAZADEH, A TOON, OB HAMILL, P AF TABAZADEH, A TOON, OB HAMILL, P TI FREEZING BEHAVIOR OF STRATOSPHERIC SULFATE AEROSOLS INFERRED FROM TRAJECTORY STUDIES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIDAR OBSERVATIONS; CLOUDS; WATER; VAPOR AB Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE I (1989) and AAOE (1987) are presented. These trajectories along with the properties of the observed PSC (polar stratospheric cloud) particles are used here to infer the physical state of the preexisting sulfuric acid aerosols. Of all the ER-2 flights described here, only the PSCs observed on the flights of January 24 and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3H2O (Type Ib PSCs). For these two days, back trajectories indicate that the air mass was exposed to SAT (sulfuric acid tetrahydrate) melting temperatures about 24 hours prior to being sampled by the ER-2. For the remaining ER-2 flights (January, 16, 19, and 20 for the AASE I campaign and August 17 for the AAOE campaign), the observed PSCs were probably composed of amorphous solid solutions of HNO3 and H2O (Type Ic PSCs). Formation of such Type Ic PSCs requires the presence of solid H2SO4 aerosols since liquid aerosols yield ternary solutions. The 10-day back trajectories of these flights indicate that the air mass was not exposed to SAT melting temperatures during the past week and had experienced cooling/warming cycles prior to being sampled by the ER-2. These temperature histories, recent laboratory measurements and the properties of glassy solids suggest that stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at similar to 198 K after going through a cooling cycle to about 194 K or lower. C1 SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 94035. RP TABAZADEH, A (reprint author), NASA,AMES RES CTR,MS 245-4,MOFFETT FIELD,CA 94035, USA. NR 23 TC 58 Z9 58 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1725 EP 1728 DI 10.1029/95GL01335 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900023 ER PT J AU GOSLING, JT MCCOMAS, DJ PHILLIPS, JL PIZZO, VJ GOLDSTEIN, BE FORSYTH, J LEPPING, RP AF GOSLING, JT MCCOMAS, DJ PHILLIPS, JL PIZZO, VJ GOLDSTEIN, BE FORSYTH, J LEPPING, RP TI A CME-DRIVEN SOLAR-WIND DISTURBANCE OBSERVED AT BOTH LOW AND HIGH HELIOGRAPHIC LATITUDES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ULYSSES AB A solar wind disturbance produced by a fast coronal mass ejection, CME, that departed from the Sun on Feburary 20, 1994 was observed in the ecliptic plane at 1 AU by IMP 8 and at high heliographic latitudes at 3.53 AU by Ulysses. In the ecliptic the disturbance included a strong forward shock but no reverse shock, while at high latitudes the disturbance was bounded by a relatively weak forward-reverse shock pair. It is clear that the disturbance in the ecliptic plane was driven primarily by the relative speed between the CME and a slower ambient solar wind ahead, whereas at higher latitudes the disturbance was driven by expansion of the CME. The combined IMP 8 and Ulysses observations thus provide a graphic illustration of how a single fast CME can produce very different types of solar wind disturbances at low and high heliographic latitudes. Simple numerical simulations help explain observed differences at the two spacecraft. C1 NOAA, SPACE ENVIRONM LAB, BOULDER, CO 80303 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV LONDON IMPERIAL COLL SCI & TECHNOL, BLACKETT LAB, LONDON SW7 2BZ, ENGLAND. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP LOS ALAMOS NATL LAB, MS D466, LOS ALAMOS, NM 87545 USA. NR 12 TC 55 Z9 56 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1753 EP 1756 DI 10.1029/95GL01776 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900030 ER PT J AU NERNEY, S SUESS, ST AF NERNEY, S SUESS, ST TI POTENTIAL FLOW DOWNSTREAM OF THE HELIOSPHERIC TERMINAL SHOCK - A NONSPHERICAL SHOCK SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC-FIELD; HELIOPAUSE AB We have solved for the potential flow downstream of the terminal shock of the solar wind in the limit of small departures from a spherical shock due to a latitudinal ram pressure variation in the supersonic solar wind. The solution connects anisotropic streamlines at the shock to uniform streamlines down the heliotail because we use a non-slip boundary condition on the heliopause at large radii. The rotational velocity about the heliotail in the near-field solution decays as the fourth power of distance from the shock. The polar divergence of the streamlines will have consequences for the previously discussed magnetic pressure ridge that may build-up just inside the heliopause. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB ES82,HUNTSVILLE,AL 35812. NR 10 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1757 EP 1760 DI 10.1029/95GL01658 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900031 ER PT J AU DESCH, MD KAISER, ML FARRELL, WM MACDOWALL, RJ STONE, RG AF DESCH, MD KAISER, ML FARRELL, WM MACDOWALL, RJ STONE, RG TI TRAVERSAL OF COMET SL-9 THROUGH THE JOVIAN MAGNETOSPHERE AND IMPACT WITH JUPITER - RADIO UPPER LIMITS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Continuous radio observations below 1 MHz of Jupiter from the Ulysses spacecraft are used to establish an upper limit to the radiated power at low frequencies associated with the traversal through the magnetosphere and impact of Comet SL-9 with the planet. Although Jovian emissions were observed throughout the impact interval, no systematic intensity changes were observed before, during, or after the fragment impact times as a whole. Examined individually, a large intensity increase, probably associated with a solar wind compression at Jupiter, was observed at the time of the P impact. Intense solar type III bursts, which can sometimes be confused with Jovian emissions, occurred often, which serves as a caution to other (groundbased) radio observers. We derive an upper limit for the interfragment dust density of 10(-3)/m(3) in the context of a dust-magnetosphere interaction model proposed earlier. RP DESCH, MD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI MacDowall, Robert/D-2773-2012; Farrell, William/I-4865-2013 NR 12 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1781 EP 1784 DI 10.1029/95GL00357 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900037 ER PT J AU KLEIN, MJ GULKIS, S BOLTON, SJ AF KLEIN, MJ GULKIS, S BOLTON, SJ TI CHANGES IN JUPITER 13-CM SYNCHROTRON RADIO-EMISSION FOLLOWING THE IMPACT OF COMET SHOEMAKER-LEVY-9 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLANETS AB Results of an observing program to monitor the synchrotron radio emission from Jupiter's inner radiation belts before, during and after the impact of Comet SL-9 are reported. The observations were made at 2295 Mhz as part of the NASA-JPL Jupiter Patrol, a long-term radio astronomy monitoring program begun in 1971. The data indicate that the intensity of the synchrotron emission at 13 cm wavelength increased by 27 percent within a few days after the comet impacts; the longitudinal beaming curve Was distorted during the week of impacts; the magnetic latitude beaming curves flattened after the week of impacts suggesting an increase in the emission at higher magnetic latitudes; and the decay of the enhanced emission is consistent with an exponential with a time constant of similar to 125 days. The reported changes following the SL-9 impact are unprecedented in the 23-year history of the Jupiter Patrol. RP KLEIN, MJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 22 Z9 22 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1797 EP 1800 DI 10.1029/95GL01415 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900041 ER PT J AU BOLTON, SJ FOSTER, RS WALTMAN, WB AF BOLTON, SJ FOSTER, RS WALTMAN, WB TI OBSERVATIONS OF JUPITER SYNCHROTRON-RADIATION AT 18 CM DURING THE COMET SHOEMAKER-LEVY/9 IMPACTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The results of observations of Jupiter's synchrotron radiation during the period surrounding the impacts of comet Shoemaker-Levy/9 are reported. The observations were made at the Naval Research Laboratory's Maryland Point Observatory 85 foot radio antenna operating at 1665 MHz (18 cm). The data indicate that an increase in the intensity of the synchrotron emission of 23% took place over the full duration of the impact period. The increase was accompanied by two characteristic changes in the beaming curve: a flattening and the creation of brightness temperature variations on hourly timescales. We interpret the latter as longitudinal variations in the beaming curve which suggests a localized mechanism resulting in a redistribution of the radiating electrons in the Jovian radiation belts. C1 USN,RES LAB,DIV REMOTE SENSING,WASHINGTON,DC 20375. RP BOLTON, SJ (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,M-S 264-744,PASADENA,CA 91109, USA. NR 16 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1801 EP 1804 DI 10.1029/95GL01516 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900042 ER PT J AU BOLTON, SJ THORNE, RM AF BOLTON, SJ THORNE, RM TI ASSESSMENT OF MECHANISMS FOR JOVIAN SYNCHROTRON VARIABILITY ASSOCIATED WITH COMET SL-9 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIATION BELT ELECTRONS; WHISTLERS AB The impact of comet SL9 with Jupiter induced a number of variations in Jupiter's synchrotron radiation; including a 20-30% increase in emission intensity, spectral changes, and a possible broadening in the latitudinal distribution of the emission. Here we consider the consequences of three potential mechanisms for inducing such effects; namely electron acceleration, radial diffusion and pitch-angle scattering. While none of the processes can be ruled out as insignificant, we show that pitch-angle scattering is consistent with al! of the available radio frequency data and demonstrate that this could be due to realistic enhanced amplitudes of cyclotron resonant whistler-mode waves associated with the comet impacts. We suggest that the waves could result from electrical storm activity or be excited by natural instabilities of the electron distribution in Jupiter's radiation belts. C1 UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,LOS ANGELES,CA 90024. RP BOLTON, SJ (reprint author), CALTECH,JET PROP LAB,M-S 169-506,PASADENA,CA 91109, USA. NR 14 TC 24 Z9 24 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1995 VL 22 IS 13 BP 1813 EP 1816 DI 10.1029/95GL01515 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RK059 UT WOS:A1995RK05900045 ER PT J AU WILSON, JW NEALY, JE WOOD, JS QUALLS, GD ATWELL, W SHINN, JL SIMONSEN, LC AF WILSON, JW NEALY, JE WOOD, JS QUALLS, GD ATWELL, W SHINN, JL SIMONSEN, LC TI VARIATIONS IN ASTRONAUT RADIATION EXPOSURE DUE TO ANISOTROPIC SHIELD DISTRIBUTION SO HEALTH PHYSICS LA English DT Article DE EXPOSURE, RADIATION; RADIATION, ATMOSPHERIC; SHIELDING; RISK ANALYSIS ID SOLAR AB The dose incurred in an environment generated by extraterrestrial space radiations within an anisotropic shield distribution depends on the orientation of the astronaut's body relative to the shield geometry. The fluctuations in exposure of specific organ sites due to astronaut re-orientation are found to be a factor of 2 or more in a typical space habitation module and typical space radiations. An approximation function is found that overestimates astronaut exposure in most cases studied and is recommended as a shield design guide for future deep space missions. C1 FLIGHT MECH CONTROL INC, HAMPTON, VA 23669 USA. ROCKWELL INT CORP, DIV INT SPACE TRANSPORTAT SYST, HOUSTON, TX 77058 USA. RP WILSON, JW (reprint author), NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NR 21 TC 8 Z9 9 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD JUL PY 1995 VL 69 IS 1 BP 34 EP 45 DI 10.1097/00004032-199507000-00005 PG 12 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA RF830 UT WOS:A1995RF83000005 PM 7790212 ER PT J AU DISANTI, MA MUMMA, MJ GEBALLE, TR DAVIES, JK AF DISANTI, MA MUMMA, MJ GEBALLE, TR DAVIES, JK TI SYSTEMATIC OBSERVATIONS OF METHANOL AND OTHER ORGANICS IN COMET P/SWIFT-TUTTLE - DISCOVERY OF NEW SPECTRAL STRUCTURE AT 3.42 MU-M SO ICARUS LA English DT Article ID EMISSION FEATURE; INFRARED-SPECTROSCOPY; HALLEYS-COMET; LEVY; ICES; IDENTIFICATION; IRRADIATION; GRAINS; MODEL; BAND AB We present a detailed study of the 3.4-mu m ''cometary organics feature'' in Comet P/Swift-Tuttle (1992 XXVIII). The study is based on spectra acquired from Kitt Peak and Mauna Kea Observatories on UT 1992 November 8, 9, 12, 13, 26, and 27, during which time the heliocentric distance decreased from 1.12 to 0.99 AU. Two distinct components are present, cometary methanol (CH3OH), and another as yet unidentified organic volatile responsible for an emission feature centered at similar to 3.424 mu m. We obtain a CH3OH abundance of 4.3 +/- 0.5% relative to H2O, revising our previously reported value of 7 +/- 1%. The revisions result from improved data analysis, inclusion of additional P/Swift-Tuttle observations, and use of corrected CH3OH g-factors. The unidentified feature consistently accounted for one-half of the flux contained in the 3.4-mu m feature and exhibited a heliocentric dependence consistent with a volatile parent species, in agreement with conclusions based on observations of several recent comets. We present the first echelle spectrum of this feature (resolving power lambda/Delta lambda approximate to 8000), which reveals spectral structure in the form of a pronounced peak centered at a rest frequency of (2920.24 +/- 0.09) cm(-1). We suspect this to be representative of asymmetric CH2 (or CH-X) vibrational stretching in some as yet unidentified organic compound. Our results indicate the presence of an additional abundant form of volatile carbon in comets. If the unidentified band(s) possess g-factors similar to those of the adjacent methanol bands, the inferred abundance of the unidentified emitting species would be comparable to that of methanol. (C) 1995 Academic Press, Inc. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,PLANETARY SYST BRANCH,GREENBELT,MD 20771. JOINT ASTRON CTR,HILO,HI 96720. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. RI mumma, michael/I-2764-2013 NR 56 TC 26 Z9 26 U1 0 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 1995 VL 116 IS 1 BP 1 EP 17 DI 10.1006/icar.1995.1110 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ716 UT WOS:A1995RJ71600001 ER PT J AU BOCKELEEMORVAN, D BROOKE, TY CROVISIER, J AF BOCKELEEMORVAN, D BROOKE, TY CROVISIER, J TI ON THE ORIGIN OF THE 3.2- TO 3.6-MU-M EMISSION FEATURES IN COMETS SO ICARUS LA English DT Article ID MICRON EMISSION; MU-M; INFRARED FLUORESCENCE; P/BRORSEN-METCALF; PARENT MOLECULES; ORGANIC GRAINS; P/HALLEY; FORMALDEHYDE; METHANOL; HALLEY AB We investigate the contribution of the nu(2), nu(3), and nu(9) CH-stretching bands of methanol to the 3.2- to 3.6-mu m emission feature observed in seven comets at a range of heliocentric distances and analyze the residual emission spectra. The comets examined are P/Halley, Wilson 1987 VII, Bradfield 1987 XXIX, P/Brorsen-Metcalf, Okazaki-Levy-Rudenko 1989 XIX, Austin 1990 V, and Levy 1990 XX. From the fitting of its nu(3) band at 3.52 mu m, we infer that methanol is present in all of the comets with abundances ranging from 0.6 to 5% with respect to water. We do not see strong evidence for a bimodal distribution of methanol-rich and methanol-poor comets, though Levy appears to be relatively low. The methanol fundamental bands are found to contribute up to 60% of the total 3.2 to 3.6-mu m emission flux. All 7 comets have residual emission with a distinct feature centered at 3.43 mu m. The flux of this 3.43-mu m feature is correlated with the water production rate, suggesting a gaseous origin, but the correlation with the methanol production rate is even tighter, suggesting a connection between the 3.43-mu m emitter and methanol. Another residual emission feature at 3.28 mu m is roughly correlated with the water production rate, but is stronger in dustier comets. If the 3.28-mu m feature is due to ultraviolet-pumped IR fluorescence of aromatic molecules, abundances between 1.5 and 10 x 10(-6) are estimated. These abundances are at least 100 times smaller than the value deduced from UV observations of P/Halley (G. Moreels et al., 1994, Astron. Astrophy. 282, 643-656), but both the UV- and IR-derived abundances depend on modeling assumptions which are still uncertain. Additional residual emission features between 3.30 and 3.40 mu m and near 3.24 mu m vary among the comets examined. In addition to the nu(2), nu(3), and nu(9) fundamental bands, overtones, and combination bands of methanol are present in the 3.2 to 3.6-mu m spectral region and may be enhanced due to Fermi resonances with the CH stretches. How this could affect the residual cometary emissions is discussed. Further laboratory work and theoretical modeling of the methanol infrared spectra are needed to fully understand the contribution of methanol to the 3.2 to 3.6-mu m spectrum of comets. (C) 1995 Academic Press, Inc. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP BOCKELEEMORVAN, D (reprint author), OBSERV PARIS,MEUDON SECT,F-92195 MEUDON,FRANCE. NR 73 TC 68 Z9 69 U1 2 U2 6 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 1995 VL 116 IS 1 BP 18 EP 39 DI 10.1006/icar.1995.1111 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ716 UT WOS:A1995RJ71600002 ER PT J AU LIOU, JC ZOOK, HA JACKSON, AA AF LIOU, JC ZOOK, HA JACKSON, AA TI RADIATION PRESSURE, POYNTING-ROBERTSON DRAG, AND SOLAR-WIND DRAG IN THE RESTRICTED 3-BODY PROBLEM SO ICARUS LA English DT Article ID PARTICLES; RESONANCE; ASTEROIDS AB In this paper, we examine the effects of radiation pressure, Poynting-Robertson (PR) drag, and solar wind drag on dust grains trapped in mean motion resonances with the Sun and Jupiter in the restricted (negligible dust mass) three-body problem. We especially examine the evolution of dust grains in the 1:1 resonance. As a first step, the Sun and Jupiter are idealized to both be in circular orbit about a common center of mass (circular restricted three-body problem). From the equation of motion of the dust particle in the rotating reference frame, the drag-induced time rate of change of its Jacobi ''constant,'' C, is then derived and expressed in spherical coordinates. This new mathematical expression in spherical coordinates shows that C, in the 1:1 resonance, both oscillates and secularly increases with increasing time. The new expression gives rise to an easy understanding of how an orbit evolves when the radiation force and solar wind drag are included. All dust grain orbits are unstable in time when PR and solar wind drag are included in the Sun-Jupiter-dust system. Tadpole orbits evolve into horseshoe orbits; and these orbits continuously expand in size to lead to close encounters with Jupiter. Permanent trapping is impossible. Orbital evolutions of a dust grain trapped in the 1:1 resonance in the planar circular, an inclined case, an eccentric case, and the actual Sun-Jupiter case are numerically simulated and compared with each other and show grossly similar time behavior. Resonances other than 1:1 are also explored with the new expression. Stable exterior resonance trapping may be possible under certain conditions. One necessary condition for such a trap is derived. Trapping in interior resonances is shown to be always unstable. (C) 1995 Academic Press, Inc. C1 LUNAR & PLANETARY INST,HOUSTON,TX 77058. RP LIOU, JC (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN3,HOUSTON,TX 77058, USA. NR 24 TC 39 Z9 39 U1 4 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUL PY 1995 VL 116 IS 1 BP 186 EP 201 DI 10.1006/icar.1995.1120 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ716 UT WOS:A1995RJ71600011 ER PT J AU KARAM, MA LEVINE, DM ANTAR, YMM STOGRYN, A AF KARAM, MA LEVINE, DM ANTAR, YMM STOGRYN, A TI IMPROVEMENT OF THE RAYLEIGH APPROXIMATION FOR SCATTERING FROM A SMALL SCATTERER SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID STRONG FLUCTUATION THEORY AB An improvement of the Rayleigh approximation for electromagnetic scattering from an arbitrary small scatterer is developed through solving the conventional integro-differential equation governing the electric field inside the scatterer. The improvement is represented by an equivalent polarizability tenser differing from that used in the Rayleigh approximation in two aspects: i) it is frequency dependent, and ii) it gives a scattering amplitude tenser satisfying energy conservation. The energy conservation is investigated through formulating the extinction, scattering, and absorption losses according to the equivalent polarizability tenser. Numerical calculations on spheres and spheroids indicate that the present extinction loss formulation has a wider validity range than the extinction loss formulation according to the Rayleigh approximation. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ROYAL MIL COLL CANADA,DEPT ELECT & COMP ENGN,KINGSTON,ON K7K 5LO,CANADA. RP KARAM, MA (reprint author), AEROJET ELECTR SYST PLANT,AZUSA,CA 91702, USA. NR 19 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JUL PY 1995 VL 43 IS 7 BP 681 EP 688 DI 10.1109/8.391139 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA RH073 UT WOS:A1995RH07300006 ER PT J AU KELKAR, AG JOSHI, SM ALBERTS, TE AF KELKAR, AG JOSHI, SM ALBERTS, TE TI PASSIVITY-BASED CONTROL OF NONLINEAR FLEXIBLE MULTIBODY SYSTEMS (VOL 40, PG 910, 1995) SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Correction, Addition C1 OLD DOMINION UNIV,NORFOLK,VA 23529. RP KELKAR, AG (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 1 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 SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD JUL PY 1995 VL 40 IS 7 BP 1328 EP 1328 PG 1 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA RH925 UT WOS:A1995RH92500030 ER PT J AU LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM AF LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM TI DOPING-SPIKE PTSI SCHOTTKY INFRARED DETECTORS WITH EXTENDED CUTOFF WAVELENGTHS SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article AB A technique incorporating a p(+) doping spike at the silicide/Si interface to reduce the effective Schottky barrier of the silicide infrared detectors and thus extend the cutoff wavelength has been developed. In contrast to previous approaches which relied on the tunneling effect, this approach utilizes a thinner doping spike (< 2 nm) to take advantage of the strong Schottky image force near the silicide/Si interface and thus avoid the tunneling effect. The critical thickness, i,e., the maximum spike thickness without the tunneling effect has been determined and the extended cutoff wavelengths have been observed for the doping-spike PtSi Schottky infrared detectors, Thermionic-emission-limited and thermally assisted tunneling dark current characteristics were observed for detectors with spikes thinner and thicker than the critical thickness, respectively. RP LIN, TL (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,TECH STAFF,PASADENA,CA 91109, USA. NR 10 TC 0 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 SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JUL PY 1995 VL 42 IS 7 BP 1216 EP 1220 DI 10.1109/16.391201 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RE530 UT WOS:A1995RE53000003 ER PT J AU STOFAN, ER EVANS, DL SCHMULLIUS, C HOLT, B PLAUT, JJ VANZYL, J WALL, SD WAY, J AF STOFAN, ER EVANS, DL SCHMULLIUS, C HOLT, B PLAUT, JJ VANZYL, J WALL, SD WAY, J TI OVERVIEW OF RESULTS OF SPACEBORNE IMAGING RADAR-C, X-BAND SYNTHETIC-APERTURE RADAR (SIR-C/X-SAR) SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID MARGINAL ICE-ZONE; FOREST BIOMASS; BACKSCATTER; DEPENDENCE; SPECTRA AB The Spaceborne Imaging Radar-C, X-Band Synthetic Aperture Radar (SIR-C/X-SAR) was launched on the Space Shuttle Endeavour for two ten day missions in the spring and fall of 1994. Radar data from these missions are being used to better understand the dynamic global environment, During each mission, radar images of over 300 sites around the Earth were obtained, returning over a terabit of data, SIR-C/X-SAR science investigations were focused on quantifying radar's ability to estimate surface properties of importance to understanding global change; and focused studies in geology, ecology, hydrology and oceanography, as well as radar calibration and electromagnetic theory studies, In addition, the second flight featured an interferometry experiment, where digital elevation maps were obtained by interfering data from the first and second shuttle flight, and from successive days on the second flight, SIR-C/X-SAR data have been used to validate algorithms which produce maps of vegetation type and biomass; snow, soil and vegetation moisture; and the distribution of wetlands, developed with earlier aircraft data. C1 DLR,INST HOCHFREQUENZTECH,W-8031 WESSLING,GERMANY. RP STOFAN, ER (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 52 TC 77 Z9 79 U1 0 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 817 EP 828 DI 10.1109/36.406668 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400001 ER PT J AU JORDAN, RL HUNEYCUTT, BL WERNER, M AF JORDAN, RL HUNEYCUTT, BL WERNER, M TI THE SIR-C/X-SAR SYNTHETIC-APERTURE RADAR SYSTEM SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB The Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) was a joint United States/German/Italian space agency imaging radar system successfully flown aboard the shuttle Endeavor in April 1994 and again in September/October 1994, The multifaceted SIR-C/X-SAR represents a major technological step forward in radar remote sensing and is the first spaceborne multifrequency, polarimetric SAR, The United States developed SIR-C operated at L- and C-band, each with quad polarization, The SIR-C antenna was an active phased array, with the capability for electronic beam steering and multiple swath width illumination, The German/Italian X-SAR operated at X-band with a single polarization using a slotted waveguide antenna, mechanically steerable in elevation, SIR-C and X-SAR were designed to operate synchronously, collecting data over common sites synchronously, A total of 143 hours (93 terabits) of SAR data were recorded on tape. RP JORDAN, RL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 84 Z9 98 U1 6 U2 18 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 829 EP 839 DI 10.1109/36.406669 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400002 ER PT J AU FREEMAN, A ALVES, M CHAPMAN, B CRUZ, J KIM, Y SHAFFER, S SUN, J TURNER, E SARABANDI, K AF FREEMAN, A ALVES, M CHAPMAN, B CRUZ, J KIM, Y SHAFFER, S SUN, J TURNER, E SARABANDI, K TI SIR-C DATA QUALITY AND CALIBRATION RESULTS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID POLARIMETRIC RADAR IMAGES; SAR AB The SIR-C/X-SAR imaging radar took its first flight on the Space Shuttle Endeavour in April 1994 and flew for a second time in October 1994. This multifrequency radar has fully polarimetric capability at L- and C-band, and a single polarization at X-band (X-SAR). The Endeavour missions were designated the Space Radar Laboratory-1 (SRL-1) and -2 (SRL-2), Calibration of polarimetric L- and C-band data for all the different modes SIR-C offers is an especially complicated problem, The solution involves extensive analysis of pre-flight test data to come up with a model of the system, analysis of in-flight test data to determine the antenna pattern and gains of the system during operation, and analysis of data from over fourteen calibration sites distributed around the SIR-C/X-SAR orbit track. The SRL missions were the first time a multifrequency polarimetric imaging radar employing a phased array antenna has been flown in space. Calibration of SIR-C data products involved some unique technical problems given the complexity of the radar system. in this paper, the approach adopted for calibration of SIR-C data is described and the calibration performance of the data products is presented. C1 UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109. RP FREEMAN, A (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 67 Z9 76 U1 2 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 848 EP 857 DI 10.1109/36.406671 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400004 ER PT J AU SARABANDI, K PIERCE, LE DOBSON, MC ULABY, FT STILES, JM CHIU, TC DEROO, R HARTIKKA, R ZAMBETTI, A FREEMAN, A AF SARABANDI, K PIERCE, LE DOBSON, MC ULABY, FT STILES, JM CHIU, TC DEROO, R HARTIKKA, R ZAMBETTI, A FREEMAN, A TI POLARIMETRIC CALIBRATION OF SIR-C USING POINT AND DISTRIBUTED TARGETS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SAR CALIBRATION; MUELLER MATRIX AB In preparation for the Shuttle Imaging Radar-C/XSAR (SIR-C/XSAR) flights, the University of Michigan has been involved in the development of calibration procedures and precision calibration devices to quantify the complex radar images with an accuracy of 0.5 dB in magnitude and 5 degrees in phase, In this paper, the preliminary results of the SIR-C calibration and a summary of the University of Michigan's activity in the Raco calibration super-site is presented. In this calibration campaign an array of point calibration targets including trihedral corner reflectors and polarimetric active radar calibrators (PARC's) in addition to a uniform distributed target were used for characterizing the radiometric calibration constant and the distortion parameters of the C-band SAR, Two different calibration methods, one based on the application of point targets and the other based on the application of the distributed target, are used to calibrate the SIR-C data and the results are compared with calibrated images provided by JPL, The distributed target used in this experiment was a held of grass, sometimes covered with snow, whose differential Mueller matrix was measured immediately after the SIR-C overpass using The University of Michigan polarimetric scatterometer systems, The scatterometers were calibrated against a precision metallic sphere and measured 100 independent spatial samples for characterizing the differential Mueller matrix of the distributed target to achieve the desired calibration accuracy, The L-band SAR has not yet been adequately calibrated for inclusion here. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP SARABANDI, K (reprint author), UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,RADIAT LAB,MICROWAVE IMAGE PROC FACIL,ANN ARBOR,MI 48109, USA. RI De Roo, Roger/J-2208-2012 OI De Roo, Roger/0000-0001-8391-2950 NR 18 TC 24 Z9 27 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 858 EP 866 DI 10.1109/36.406672 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400005 ER PT J AU RANSON, KJ SAATCHI, S SUN, GQ AF RANSON, KJ SAATCHI, S SUN, GQ TI BOREAL FOREST ECOSYSTEM CHARACTERIZATION WITH SIR-C/XSAR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID RADAR IMAGES; CLASSIFICATION; BIOMASS AB This paper discusses early results obtained from Spaceborne Imaging Radar-C (SIR-C) and X-band synthetic aperture radar (XSAR) data over a boreal forest in Saskatchewan, Canda. Multifrequency and multipolarization image data were made available during the SRL-1 (Apr. 10, 1994) and SRL-2 (Oct. 1, 1994) missions. These image data sets were analyzed and maps of forest cover type and above ground woody dry biomass were generated. A portion of the Southren Study Area of the Boreal Ecosystem-Atmosphere Study (BOREAS) was mapped for forest cover type with classification accuracies on the order of 80%, Maps of estimated biomass were also produced that match observed patterns and preliminary ground data, The upper limit of sensitivity of the radar to boreal forest biomass in our study area was about 20 kg/m(2) or 200 tons/ha, The highest average observed biomass in our ground measurements was about 25 kg/m(2). Highest sensitivity of the radar to biomass was attained using April backscatter data and a ratio of L-band HV to C-band HV. Results show that radar estimates of biomass were within +/- 2 kg/m(2) at the 95% confidence level, A comparison of the April and October data sets was conducted to understand the effects of seasons on the analysis. It appears that the frozen trees and wetter background contributes to increased backscattering observed in the April data, These early results indicate that multiple polarization and multiple frequency SAR data can be used to monitor and map northern forest biomes. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. SCI SYST APPLICAT INC,LANHAM,MD 20706. RP RANSON, KJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 24 TC 78 Z9 80 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 867 EP 876 DI 10.1109/36.406673 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400006 ER PT J AU DUBOIS, PC VANZYL, J ENGMAN, T AF DUBOIS, PC VANZYL, J ENGMAN, T TI MEASURING SOIL-MOISTURE WITH IMAGING RADARS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID CALIBRATION; SCATTERING; IMAGES; MODEL AB An empirical algorithm for the retrieval of soil moisture content and surface Root Mean Square (RMS) height from remotely sensed radar data was developed using scatterometer data, The algorithm is optimized for bare surfaces and requires two copolarized channels at a frequency between 1.5 and 11 GHz. It gives best results for kh less than or equal to 2.5, mu nu, less than or equal to 35%, and theta greater than or equal to 30 degrees. Omitting the usually weaker hv-polarized returns makes the algorithm less sensitive to system cross-talk and system noise, simplify the calibration process and adds robustness to the algorithm in the presence of vegetation, However, inversion results indicate that significant amounts of vegetation (NDVI > 0.4) cause the algorithm to underestimate soil moisture and overestimate RMS height. A simple criteria based on the sigma(hv)(O)/sigma(vv)(O) ratio is developed to select the areas where the inversion is not impaired by the vegetation. The inversion accuracy is assessed on the original scatterometer data sets but also on several SAR data sets by comparing the derived soil moisture values with in-situ measurements collected over a variety of scenes between 1991 and 1994, Both spaceborne (SIR-C) and airborne (AIRSAR) data are used in the test, Over this large sample of conditions, the RMS error in the soil moisture estimate is found to be less than 4.2% soil moisture. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP DUBOIS, PC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91009, USA. RI Mitchard, Edward/C-6346-2009; Dubois-Fernandez, Pascale/A-6743-2012 NR 42 TC 420 Z9 464 U1 3 U2 43 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 915 EP 926 DI 10.1109/36.406677 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400010 ER PT J AU ITO, S OGUCHI, T IGUCHI, T KUMAGAI, H MENEGHINI, R AF ITO, S OGUCHI, T IGUCHI, T KUMAGAI, H MENEGHINI, R TI DEPOLARIZATION OF RADAR SIGNALS DUE TO MULTIPLE-SCATTERING IN RAIN SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID RADIATIVE-TRANSFER EQUATION; BACKSCATTERING; LIGHT; MEDIA AB The linear depolarization ratio (LDR) of radar returns from rain is studied, Pulse intensities of copolarized and cross-polarized components are calculated by using the second-order solution of the time-dependent radiative transfer equation for a finite rain layer composed of spherical raindrops, Theoretical results show significant differences in LDR values between X and Ka bands for light to moderate rainfall rates and a rapid increase in the LDR reaching a level of about - 8.5 dB at radar ranges near the rear edge of the rain layer. These characteristics of the LDR are in good agreement with observations from an air-borne dual-frequency, dual-polarized radar and suggest that a part of the depolarized radar power is caused by second-order multiple scattering effects. C1 TOKYO METROPOLITAN INST TECHNOL,HINO,TOKYO 191,JAPAN. COMMUN RES LABS,KOGANEI,TOKYO 184,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP ITO, S (reprint author), TOYO UNIV,FAC ENGN,KAWAGOE,SAITAMA 350,JAPAN. NR 13 TC 20 Z9 20 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1995 VL 33 IS 4 BP 1057 EP 1062 DI 10.1109/36.406691 PG 6 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RQ874 UT WOS:A1995RQ87400024 ER PT J AU HERMAN, MI LEE, KA KOLAWA, EA LOWRY, LE TULINTSEFF, AN AF HERMAN, MI LEE, KA KOLAWA, EA LOWRY, LE TULINTSEFF, AN TI NOVEL TECHNIQUES FOR MILLIMETER-WAVE PACKAGES SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article ID MICROSTRIP LINES AB A new millimeter-wave package architecture with supporting electrical, mechanical and material science experiment and analysis is presented, This package is well suited for discrete devices, monolithic microwave integrated circuits (MMIC's) and multichip module (MCM) applications. It has low-loss wideband RF transitions which are necessary to overcome manufacturing tolerances leading to lower per unit cost, Potential applications of this new packaging architecture which go beyond the standard requirements of device protection include integration of antennas, compatibility to photonic networks and direct transitions to waveguide systems. Techniques for electromagnetic analysis, thermal control and hermetic sealing mere explored. Three dimensional electromagnetic analysis was performed using a finite-difference time-domain (FDTD) algorithm and experimentally verified for millimeter-wave package input and output transitions. New multi-material system concepts (AIN, Cu, and diamond thin films) which allow excellent surface finishes to be achieved with enhanced thermal management have been investigated, A new approach utilizing block copolymer coatings was employed to hermetically seal packages which met MIL STD-883. RP HERMAN, MI (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 32 TC 8 Z9 8 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JUL PY 1995 VL 43 IS 7 BP 1516 EP 1523 DI 10.1109/22.392909 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA RH824 UT WOS:A1995RH82400013 ER PT J AU BALDI, PF HORNIK, K AF BALDI, PF HORNIK, K TI LEARNING IN LINEAR NEURAL NETWORKS - A SURVEY SO IEEE TRANSACTIONS ON NEURAL NETWORKS LA English DT Article ID PRINCIPAL-COMPONENT ANALYSIS; EIGENVALUES; ARCHITECTURE; EIGENVECTORS; CONVERGENCE; ALGORITHMS; EMERGENCE; EXAMPLES; MATRICES; SYSTEMS AB Networks of linear units are the simplest kind of networks, where the basic questions related to learning, generalization, and self-organization can sometimes be answered analytically, We survey most of the known results on linear networks, including: 1) backpropagation learning and the structure of the error function landscape, 2) the temporal evolution of generalization, and 3) unsupervised learning algorithms and their properties, The connections to classical statistical ideas, such as principal component analysis (PCA), are emphasized as well as several simple but challenging open questions, A few new results are also spread across the paper, including an analysis of the effect of noise on backpropagation networks and a unified view of all unsupervised algorithms. C1 CALTECH,DIV BIOL,PASADENA,CA 91109. VIENNA TECH UNIV,INST STAT & WAHRSCHEINLICHKEITSTHEORIE,A-1040 VIENNA,AUSTRIA. RP BALDI, PF (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 52 TC 107 Z9 112 U1 3 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1045-9227 J9 IEEE T NEURAL NETWOR JI IEEE Trans. Neural Netw. PD JUL PY 1995 VL 6 IS 4 BP 837 EP 858 DI 10.1109/72.392248 PG 22 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA RF582 UT WOS:A1995RF58200004 PM 18263374 ER PT J AU CHIEN, S GRATCH, J BURL, M AF CHIEN, S GRATCH, J BURL, M TI ON THE EFFICIENT ALLOCATION OF RESOURCES FOR HYPOTHESIS EVALUATION - A STATISTICAL APPROACH SO IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE LA English DT Article DE MACHINE LEARNING; THE UTILITY PROBLEM; PLANNING AND SCHEDULING; PARAMETER ESTIMATION; ADAPTIVE PROBLEM-SOLVING AB This paper considers the decision-making problem of selecting a strategy from a set of alternatives on the basis of incomplete information (e.g., a finite number of observations). At any time the system can adopt a particular strategy or decide to gather additional information at some cost. Balancing the expected utility of the new information against the cost of acquiring the information is the central problem we address. In our approach, the cost and utility of applying a particular strategy to a given problem are represented as random variables from a parametric distribution. By observing the performance of each strategy on a randomly selected sample of problems, we can use parameter estimation techniques to infer statistical models of performance on the general population of problems. These models can then be used to estimate: 1) the utility and cost of acquiring additional information and 2) the desirability of selecting a particular strategy from a set of choices. Empirical results are presented that demonstrate the effectiveness of the hypothesis evaluation techniques for tuning system parameters in a NASA antenna scheduling application. C1 UNIV SO CALIF,DEPT COMP SCI,LOS ANGELES,CA 90089. UNIV ILLINOIS,BECKMAN INST,URBANA,IL 61801. RP CHIEN, S (reprint author), CALTECH,JET PROP LAB,ADV INFORMAT SYST SECT,ARTIFICIAL INTELLIGENCE GRP,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 24 TC 12 Z9 12 U1 0 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0162-8828 J9 IEEE T PATTERN ANAL JI IEEE Trans. Pattern Anal. Mach. Intell. PD JUL PY 1995 VL 17 IS 7 BP 652 EP 665 DI 10.1109/34.391408 PG 14 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA RF224 UT WOS:A1995RF22400002 ER PT J AU PATWARDHAN, AR EVANS, JM BERK, M GRANDE, KJ CHARLES, JB KNAPP, CF AF PATWARDHAN, AR EVANS, JM BERK, M GRANDE, KJ CHARLES, JB KNAPP, CF TI SPECTRAL INDEXES OF CARDIOVASCULAR ADAPTATIONS TO SHORT-TERM SIMULATED MICROGRAVITY EXPOSURE SO INTEGRATIVE PHYSIOLOGICAL AND BEHAVIORAL SCIENCE LA English DT Article DE SYMPATHETIC PARASYMPATHETIC BALANCE; HEART RATE AND BLOOD PRESSURE SPECTRA; HEAD DOWN BEDREST ID HEART-RATE-VARIABILITY; RESPIRATORY SINUS ARRHYTHMIA; ARTERIAL-PRESSURE; BLOOD-PRESSURE; DOWN TILT; HUMANS; RESPONSES; ATROPINE; BEDREST; FLIGHT AB We investigated the effects of exposure to microgravity on the baseline autonomic balance in cardiovascular regulation using spectral analysis of cardiovascular variables measured during supine rest. Heart rate, arterial pressure, radial flow, thoracic fluid impedance and central venous pressure were recorded from nine volunteers before and after simulated microgravity, produced by 20 hours of 6 degrees head down bedrest plus furosemide. Spectral powers increased after simulated microgravity in the low frequency region (centered at about 0.03 Hz) in arterial pressure, heart rate and radial flow, and decreased in the respiratory frequency region (centered at about 0.25 Hz) in heart rate. Reduced heart rate power in the respiratory frequency region indicates reduced parasympathetic influence on the heart. A concurrent increase in the low frequency power in arterial pressure, heart rate, and radial flow indicates increased sympathetic influence. These results suggest that the baseline autonomic balance in cardiovascular regulation is shifted towards increased sympathetic and decreased parasympathetic influence after exposure to short-term simulated microgravity. C1 UNIV KENTUCKY,DIV CARDIOL,LEXINGTON,KY 40506. NASA,LYNDON B JOHNSON SPACE CTR,CARDIOVASC LAB,HOUSTON,TX 77058. RP PATWARDHAN, AR (reprint author), UNIV KENTUCKY,CTR BIOMED ENGN,WENNER GREN RES LAB 2,LEXINGTON,KY 40506, USA. RI Grande-Allen, Kathryn/P-4042-2014 OI Grande-Allen, Kathryn/0000-0003-1533-3767 FU PHS HHS [M01-2602] NR 36 TC 5 Z9 5 U1 2 U2 3 PU TRANSACTION PERIOD CONSORTIUM PI NEW BRUNSWICK PA DEPT 3091 RUTGERS-THE STATE UNIV OF NJ, NEW BRUNSWICK, NJ 08903 SN 1053-881X J9 INTEGR PHYS BEH SCI JI Integr. Physiol. Behav. Sci. PD JUL-SEP PY 1995 VL 30 IS 3 BP 201 EP 214 DI 10.1007/BF02698574 PG 14 WC Psychology, Biological; Neurosciences SC Psychology; Neurosciences & Neurology GA RQ676 UT WOS:A1995RQ67600003 PM 7577683 ER PT J AU SHAMANNA, M CAMERON, K WHITAKER, SR AF SHAMANNA, M CAMERON, K WHITAKER, SR TI MULTIPLE-INPUT, MULTIPLE-OUTPUT PASS TRANSISTOR LOGIC SO INTERNATIONAL JOURNAL OF ELECTRONICS LA English DT Article AB Techniques are presented for the design of multiple-input, multiple-output pass transistor circuits. By using shared functions as map-entered variables, dramatic reductions in transistor count can be achieved. Applied to a Viterbi decoder design for NASA, the transistor count of a CMOS integrated circuit was reduced by nearly 100 000 transistors over the best previously known techniques. A proof is presented which lowers the known theoretical upper bound on transistor count for circuits with six or more input variables. The implementation of practical single-output functions of less than six input variables is also shown to benefit from these techniques. C1 UNIV NEW MEXICO,NASA,SPACE ENGN RES CTR VLSI SYST DESIGN,ALBUQUERQUE,NM 87106. RP SHAMANNA, M (reprint author), SOMERSET MOTOROLA INC,GREAT HILLS TRAIL,AUSTIN,TX 78731, USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0020-7217 J9 INT J ELECTRON JI Int. J. Electron. PD JUL PY 1995 VL 79 IS 1 BP 33 EP 45 DI 10.1080/00207219508926248 PG 13 WC Engineering, Electrical & Electronic SC Engineering GA RL774 UT WOS:A1995RL77400005 ER PT J AU TSUJIKAWA, Y NORTHAM, GB AF TSUJIKAWA, Y NORTHAM, GB TI OPTIMIZATION OF SCRAMJET ENGINE PERFORMANCE WITH THE 3-TEMPERATURE FLOW MODEL SO INTERNATIONAL JOURNAL OF HYDROGEN ENERGY LA English DT Article AB An important element in the spaceplane research program is the development of the analytical tools or models that are needed for analyzing and gaining insight into the combustion problems associated with propulsion systems required to operate at flight speeds up to Mach 25. The three-temperature modes applied to the flow in the scramjet combustor. Separate temperatures are assigned to the hydrogen, the air and the ignition source material. A mixing routine is included in the model which allows the unmixed fuel and air to be mixed at a prescribed schedule along the combustor. The area distribution along the flow direction is used as a design parameter and is optimized by the multiplier method. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP TSUJIKAWA, Y (reprint author), UNIV OSAKA PREFECTURE,1-1 GAKUEN CHO,SAKAI 593,JAPAN. NR 9 TC 1 Z9 1 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0360-3199 J9 INT J HYDROGEN ENERG JI Int. J. Hydrog. Energy PD JUL PY 1995 VL 20 IS 7 BP 593 EP 599 DI 10.1016/0360-3199(94)00098-K PG 7 WC Chemistry, Physical; Electrochemistry; Energy & Fuels SC Chemistry; Electrochemistry; Energy & Fuels GA RC154 UT WOS:A1995RC15400010 ER PT J AU KAISER, DK AF KAISER, DK TI HUMAN-FACTORS IN ALARM DESIGN - STANTON,N SO INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS LA English DT Book Review RP KAISER, DK (reprint author), NASA,AMES RES CTR,BOEING AEROSP OPERAT,M-S 19-21,MT VIEW,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-8141 J9 INT J IND ERGONOM JI Int. J. Ind. Ergon. PD JUL PY 1995 VL 16 IS 1 BP 74 EP 75 DI 10.1016/0169-8141(95)90012-8 PG 2 WC Engineering, Industrial; Ergonomics SC Engineering GA RK300 UT WOS:A1995RK30000008 ER PT J AU MADENCI, E ILERI, L STARNES, JH AF MADENCI, E ILERI, L STARNES, JH TI ANALYSIS OF PIN-LOADED HOLES IN COMPOSITE LAMINATES UNDER COMBINED BEARING-BYPASSS AND SHEAR LOADING SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article AB This study investigates the contact stresses in single-fastener mechanical joints in composite laminates with finite boundaries subjected to combined bearing-bypass and shear loading. The bearing stresses and the contact region are determined by imposing the appropriate mixed boundary conditions along the boundary of the hole. No-slip and slip zones of the contact region arising from the presence of friction are obtained as part of the analysis. A boundary collocation method, in conjunction with a complex variable formulation of the solution for anisotropic laminates, is utilized in the analysis. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP MADENCI, E (reprint author), UNIV ARIZONA,DEPT AEROSP & MECH ENGN,TUCSON,AZ 85721, USA. NR 7 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD JUL PY 1995 VL 32 IS 14 BP 2053 EP 2062 DI 10.1016/0020-7683(94)00218-L PG 10 WC Mechanics SC Mechanics GA RC178 UT WOS:A1995RC17800007 ER PT J AU ZANETTI, LJ POTEMRA, TA AF ZANETTI, LJ POTEMRA, TA TI MAGNETIC-FIELD EXPERIMENT ON THE SWEDISH FREJA SATELLITE SO JOHNS HOPKINS APL TECHNICAL DIGEST LA English DT Article AB Freja is a joint Swedish and German scientific satellite launched on 6 October 1992 to acquire high-resolution measurements of plasmas, fields, and ultraviolet emissions associated with auroral phenomena. The Magnetic Field Experiment was developed by APL and incorporates a ring-core fluxgate sensor and an APL-designed Forth reduced instruction set computer microprocessor. This programmable microprocessor has significant advantages including (1) the flexibility to adapt to different mission requirements with only software changes, (2) the ability to substantially reduce the need for ground-based data processing with powerful onboard rear-time processing, and (3) the capacity to increase the sensitivity and resolution of the basic measurements using onboard processing to compress the data stream to fit the available telemetry bandwidth. The Freja mission enables real-time data display on a laptop-sized computer linked to the ground receiving station in Kiruna, Sweden. This PC-telephone link also provides the real-time means to send commands to Freja to change instrument modes and even to reprogram the entire processor. The details of this unique instrument and satellite mission and some uses of its real-time data capabilities are described in this article. RP ZANETTI, LJ (reprint author), NASA,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHNS HOPKINS UNIV PI LAUREL PA APPLIED PHYSICS LABORATORY ATTN: MANAGING EDITOR JOHN HOPKINS RD, BLDG 1-E254, LAUREL, MD 20723-6099 SN 0270-5214 J9 J HOPKINS APL TECH D JI Johns Hopkins APL Tech. Dig. PD JUL-SEP PY 1995 VL 16 IS 3 BP 233 EP 245 PG 13 WC Engineering, Multidisciplinary SC Engineering GA RM669 UT WOS:A1995RM66900003 ER PT J AU BOITNOTT, RL STARNES, JH JOHNSON, ER AF BOITNOTT, RL STARNES, JH JOHNSON, ER TI NONLINEAR RESPONSE AND FAILURE OF PRESSURIZED COMPOSITE CURVED PANELS SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB Results of an experimental and analytical study of the nonlinear response and failure characteristics of internally pressurized 4- to 16-ply-thick graphite-epoxy cylindrical panels are presented. Specimens were clamped in a test fixture to simulate the skin between two frames and two stringers of a typical transport fuselage and tested to failure, Aluminum specimens were also tested to failure and the results of these tests are compared with the graphite-epoxy test results. The graphite-epoxy specimens failed at their edges where the magnitudes of severe local bending gradients and interlaminar stresses are maximum. A shell analysis using the STAGS computer code showed that the response is independent of the axial coordinate outside of the bending boundary layers at the curved ends. A nonlinear, one-dimensional analysis in the circumferential coordinate is developed that includes transverse shearing deformations and computes interlaminar stresses. Accurate panel radius measurements and measurements of edge circumferential displacements associated with specimen slipping were required in the one-dimensional analysis to obtain good correlation between analytical and experimental results. Results indicate that all panels tested, including the thin four-ply panels, can support supplied internal pressures that are well above the proof pressure loading expected for transport fuselage structures. C1 NASA,LANGLEY RES CTR,DIV STRUCT,STRUCT MECH BRANCH,HAMPTON,VA 23665. VIRGINIA POLYTECH INST & STATE UNIV,DEPT AEROSP & OCEAN ENGN,BLACKSBURG,VA 24061. RP BOITNOTT, RL (reprint author), USA,RES LAB,LANGLEY RES CTR,VEHICLE STRUCT DIRECTORATE,HAMPTON,VA 23681, USA. NR 15 TC 2 Z9 2 U1 2 U2 4 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JUL PY 1995 VL 8 IS 3 BP 129 EP 138 DI 10.1061/(ASCE)0893-1321(1995)8:3(129) PG 10 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA RZ835 UT WOS:A1995RZ83500001 ER PT J AU SPANOS, PD EBERLE, RR HAMILTON, D MUSHUNG, L AF SPANOS, PD EBERLE, RR HAMILTON, D MUSHUNG, L TI TRIVARIATE SPECTRAL MODELING OF SPACE-SHUTTLE FLIGHT DATA SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article ID MULTIVARIATE RANDOM-PROCESSES; RECURSIVE SIMULATION AB Acceleration time histories recorded during liftoff in six Space Shuttle flights are analyzed digitally. Accelerations are measured in the three axial directions of the shuttle using accelerometers calibrated for the 0-50 Hz range. The event analyzed involves the interval beginning at solid rocket booster ignition and lasting for 2.5 sec. During this interval the data are assumed to be realizations of a stationary trivariate random process, Power spectral density models are formulated using a two-stage auto/cross-correlation matching (ACM) technique. In this technique, the spectra of the vector process representing the measured data are modeled using an autoregressive (AR) filter, From this filter, a reduced-order autoregressive moving average (ARMA) model is formulated. Further, when considering a univariate random process, additional order reduction is achieved by using a novel modal-energy-based, system order-reduction technique applied to the initial AR model. The numerical results of this paper should be viewed in contest with the usefulness for Space Shuttle related studies of information on the degree of correlation of excitations along different geometrical axes; also, the derivation of simplified univariate power spectra for design purposes is useful. C1 RICE UNIV,DEPT MECH ENGN & MAT SCI,HOUSTON,TX 77251. NASA,LYNDON B JOHNSON SPACE CTR,LOADS & STRUCT DYNAM BRANCH,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. RP SPANOS, PD (reprint author), RICE UNIV,LB RYON CHAIR ENGN,POB 1892,HOUSTON,TX 77251, USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JUL PY 1995 VL 8 IS 3 BP 148 EP 155 DI 10.1061/(ASCE)0893-1321(1995)8:3(148) PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA RZ835 UT WOS:A1995RZ83500003 ER PT J AU STRAWN, RC BISWAS, R GARCEAU, M AF STRAWN, RC BISWAS, R GARCEAU, M TI UNSTRUCTURED ADAPTIVE MESH COMPUTATIONS OF ROTORCRAFT HIGH-SPEED IMPULSIVE NOISE SO JOURNAL OF AIRCRAFT LA English DT Article AB A new method is developed for modeling helicopter high-speed impulsive (HSI) noise. The aerodynamics and acoustics near the rotor blade tip are computed by solving the Euler equations on an unstructured grid, A stationary Kirchhoff surface integral is then used to propagate these acoustic signals to the far field, The near-field Euler solver uses a solution-adaptive grid scheme to improve the resolution of the acoustic signal, Grid points are locally added and/or deleted from the mesh at each adaptive step, An important part of this procedure is the choice of an appropriate error indicator, The error indicator is computed from the flowfield solution and determines the regions for mesh coarsening and refinement, Computed results for HSI noise compare favorably with experimental data for three different hovering rotor cases. RP STRAWN, RC (reprint author), NASA,AMES RES CTR,USA,AVIAT & TROOP COMMAND,AEROFLIGHTDYNAM DIRECTORATE,M-S 258-1,MOFFETT FIELD,CA 94035, USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 1995 VL 32 IS 4 BP 754 EP 760 DI 10.2514/3.46787 PG 7 WC Engineering, Aerospace SC Engineering GA RP012 UT WOS:A1995RP01200010 ER PT J AU HEIDELBERG, LJ HALL, DG AF HEIDELBERG, LJ HALL, DG TI INLET ACOUSTIC MODE MEASUREMENTS USING A CONTINUOUSLY ROTATING RAKE SO JOURNAL OF AIRCRAFT LA English DT Article AB Comprehensive measurements of the spinning acoustic mode structure in the inlet of the advanced ducted propeller were obtained using a unique method that was first proposed by Sofrin. A continuously rotating microphone system was employed. Three inlet configurations with cut-on as well as cut-off stator vane sets were tested. The cut-off stator was designed to suppress all modes at the blade passing frequency. Rotating rake measurements indicate: that several extraneous circumferential modes, possibly due to the interaction between the rotor and small interruptions in the casing tip treatment, were present. The cut-on stator produced the expected circumferential modes plus higher levels of the unexpected modes seen with the cut-off stator. RP HEIDELBERG, LJ (reprint author), NASA,LEWIS RES CTR,M-S 77-6,CLEVELAND,OH 44135, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 1995 VL 32 IS 4 BP 761 EP 767 DI 10.2514/3.46788 PG 7 WC Engineering, Aerospace SC Engineering GA RP012 UT WOS:A1995RP01200011 ER PT J AU ATWOOD, CA AF ATWOOD, CA TI COMPUTATION OF A CONTROLLED STORE SEPARATION FROM A CAVITY SO JOURNAL OF AIRCRAFT LA English DT Article AB Coupling of the Reynolds-averaged Navier-Stokes equations, rigid-body dynamics, and a pitch-attitude control law is demonstrated in two and three dimensions, The application problem was the separation of a canard-controlled store from an open-flow rectangular cavity at a freestream Mach number of 1.2. The transient flowfield was computed using a diagonal scheme in an overset mesh framework, with the resultant aerodynamic loads used as the forcing functions in the nonlinear dynamics equations. The proportional and rate gyro sensitivities were computed via pole placement techniques for the linearized dynamical equations, in which computed aerodynamic stability derivatives were used, In two dimensions, a comparison between full and linearized now equations for a perturbed pinned missile was made, and a controlled store was found to possess improved separation characteristics over a canard-fixed store, in three dimensions, trajectory comparisons with quasisteady wind-tunnel data for the canard-fixed case were made, Comparisons of canard-fixed and canard-active simulations showed that controlled store offers only modest improvements in cavity separation characteristics for these high-ejection rate cases. RP ATWOOD, CA (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JUL-AUG PY 1995 VL 32 IS 4 BP 846 EP 852 DI 10.2514/3.46800 PG 7 WC Engineering, Aerospace SC Engineering GA RP012 UT WOS:A1995RP01200023 ER PT J AU WANG, JR MELFI, SH RACETTE, P WHITEMEN, DN CHANG, LA FERRARE, RA EVANS, KD SCHMIDLIN, FJ AF WANG, JR MELFI, SH RACETTE, P WHITEMEN, DN CHANG, LA FERRARE, RA EVANS, KD SCHMIDLIN, FJ TI SIMULTANEOUS MEASUREMENTS OF ATMOSPHERIC WATER-VAPOR WITH MIR, RAMAN LIDAR, AND RAWINSONDES SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID MICROWAVE RADIOMETRY; MOISTURE PROFILES; RETRIEVAL; SATELLITE; AEROSOLS; CLEAR; MODEL; GHZ AB Simultaneous measurements of atmospheric water vapor were made by the Millimeter-wave Imaging Radiometer (MIR), Raman lidar, and rawinsondes. Two types of rawinsonde sensor packages (AIR and Vaisala) were carried by the same balloon. The measured water vapor profiles from Raman lidar, and the Vaisala and AIR sondes were used in the radiative transfer calculations. The calculated brightness temperatures were compared with those measured from the MIR at all six frequencies (89, 150, 183.3 +/- 1, 183.3 +/- 3, 183.3 +/- 7, and 220 GHz). The results show that the MIR-measured brightness temperatures agree well (within +/-2 K) with those calculated from the Raman lidar and Vaisala measurements. The brightness temperatures calculated from the AIR sondes differ from the MIR measurements by as much as 10 K, which can be attributed to low sensitivity of the AIR sondes at relative humidity less than 20%. Both calculated and the MIR-measured brightness temperatures were also used to retrieve water vapor profiles. These retrieved profiles were compared with those measured by the Raman lidar and rawinsondes. The results of these comparisons suggest that the MIR can measure the brightness of a target to an accuracy of at most +/-2 K and is capable of retrieving useful water vapor profiles. C1 FUTURETECH CORP,GAITHERSBURG,MD. HUGHES STX CORP,LANHAM,MD. NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. RP WANG, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 975,GREENBELT,MD 20771, USA. NR 38 TC 21 Z9 21 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 1995 VL 34 IS 7 BP 1595 EP 1607 DI 10.1175/1520-0450-34.7.1595 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RE824 UT WOS:A1995RE82400009 ER PT J AU SCHACHAM, SE MENA, RA HAUGLAND, EJ ALTEROVITZ, SA AF SCHACHAM, SE MENA, RA HAUGLAND, EJ ALTEROVITZ, SA TI 2 CARRIER ANALYSIS OF PERSISTENT PHOTOCONDUCTIVITY IN MODULATION-DOPED STRUCTURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DIMENSIONAL ELECTRON-GAS; FIELD-EFFECT TRANSISTORS; ALXGA1-XAS/GAAS HETEROSTRUCTURES; GAAS/ALXGA1-XAS HETEROJUNCTIONS; QUANTUM WELLS; MOBILITY; GAAS; TEMPERATURE; RELAXATION; MODEL RP SCHACHAM, SE (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 38 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1995 VL 78 IS 1 BP 321 EP 329 DI 10.1063/1.360679 PG 9 WC Physics, Applied SC Physics GA RE582 UT WOS:A1995RE58200047 ER PT J AU PLOUTZSNYDER, LL TESCH, PA CRITTENDEN, DJ DUDLEY, GA AF PLOUTZSNYDER, LL TESCH, PA CRITTENDEN, DJ DUDLEY, GA TI EFFECT OF UNWEIGHTING ON SKELETAL-MUSCLE USE DURING EXERCISE SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE MAGNETIC RESONANCE IMAGING; NEUROMUSCULAR; ACTIVATION; ATROPHY ID LOWER-LIMB SUSPENSION; HUMAN QUADRICEPS; MOTOR UNITS; PROTON T2; BED REST; STRENGTH; IMMOBILIZATION; SPECTROSCOPY; ACTIVATION; VOLUNTARY AB Exercise-induced spin-spin relaxation time (T-2) shifts in magnetic resonance (MR) images were used to test the hypothesis that more muscle would be used to perform a given submaximal task after 5 wk of unweighting. Before and after unilateral lower Limb suspension (ULLS), 7 subjects performed 5 sets of 10 unilateral concentric actions with the quadriceps femoris muscle group (QF) at each of 4 loads: 25, 40, 55, and 70% of maximum. T-2-weighted MR images of the thigh were collected at rest and after each relative load. ULLS elicited a 20% decrease in strength of the left unweighted QF and a 14% decrease in average cross-sectional area (CSA) with no changes in the right weight-bearing QF. Average CSA of the left or right QF showing exercise-induced T-2 shift increased as a function of exercise intensity both before and after ULLS. On average, 12 +/- 1, 15 +/- 2, 18 +/- 2, and 22 +/- 1 cm(2) of either QF showed elevated T-2 for the 25, 40, 55, and 70% loads, respectively, before ULLS. Average CSA of the left but not the right QF, showing elevated T-2 after ULLS, was increased to 16 +/- 2, 23 +/- 3, 31 +/ 7, and 39 +/- 5 cm(2), respectively. The results indicated that unweighting increased exercise-induced T-2 shift in MR images, presumably due to greater muscle mass involvement in exercise after than before unweighting, suggesting a change in motor control. C1 KAROLINSKA INST,DEPT PHYSIOL & PHARMACOL,S-17177 STOCKHOLM,SWEDEN. UNIV CENT FLORIDA,DEPT HLTH SCI,ORLANDO,FL 32816. NASA,BIOMED OPERAT & RES OFF,KENNEDY SPACE CTR,FL 32899. RP PLOUTZSNYDER, LL (reprint author), OHIO UNIV,DEPT BIOL SCI,IRVINE HALL,ATHENS,OH 45701, USA. NR 36 TC 67 Z9 67 U1 0 U2 4 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUL PY 1995 VL 79 IS 1 BP 168 EP 175 PG 8 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA RK488 UT WOS:A1995RK48800026 PM 7559216 ER PT J AU ROSENFIELD, JE AF ROSENFIELD, JE TI THE SENSITIVITY OF STRATOSPHERIC PHOTODISSOCIATION RATES TO THE SOLAR SPECTRAL RESOLUTION IN THE SCHUMANN-RUNGE BANDS SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID CROSS-SECTIONS; IRRADIANCE AB Several molecules important in the chemistry of the stratosphere, including N2O, H2O, HNO3, and several chlorofluorocarbons, photodissociate in the wavelength interval 1750-2050 Angstrom. The transmission of solar radiation in this spectral region is largely controlled by the Schumann-Runge (S-R) bands of molecular oxygen. The absorption cross sections of oxygen in this region vary by several orders of magnitude as a function of wavelength, resulting in large variations in the magnitude of solar radiation penetrating into the middle atmosphere. It is thus of interest to examine the potential effects that a knowledge of the fine structure of the solar spectrum would have on the accurate calculation of stratospheric photodissociation rates. A U.S. Naval Research Laboratory solar spectrum with a resolution of 0.07 Angstrom has been used to compute high resolution photodissociation rates for several molecular species. Computations have also been performed in which this solar spectrum has been degraded by roughly a factor of 100. These calculations show that knowledge of the fine structure in the S-R region of the solar spectrum produces only a marginal (1-2%) improvement in the computation of the photodissociation rates. This results from the fact that the photodissociation rate is a spectrally integrated quantity, and that there is, on average over the S-R bands, no correlation between the solar spectrum and the oxygen absorption cross sections. This very small improvement should be compared with the much larger uncertainties in important chemical reaction rates, absorption cross sections, and quantum yields, which are often 50-100%. C1 GODDARD SPACE FLIGHT CTR,GREENBELT,MD. RP ROSENFIELD, JE (reprint author), APPL RES CORP,LANDOVER,MD 20785, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD JUL PY 1995 VL 57 IS 8 BP 847 EP 855 DI 10.1016/0021-9169(94)00069-Z PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RA328 UT WOS:A1995RA32800002 ER PT J AU BOROWSKI, P ROOS, BO RACINE, SC LEE, TJ CARTER, S AF BOROWSKI, P ROOS, BO RACINE, SC LEE, TJ CARTER, S TI THE OZONIDE ANION - A THEORETICAL-STUDY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SELF-CONSISTENT FIELD; ANHARMONIC POTENTIAL FUNCTION; 2ND-ORDER PERTURBATION-THEORY; ARGON MATRIX; VIBRATIONAL FREQUENCIES; ELECTRON-AFFINITY; INFRARED-SPECTRA; BASIS-SETS; O-3; ENERGY C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV READING,DEPT CHEM,READING RG6 2AD,BERKS,ENGLAND. RP BOROWSKI, P (reprint author), CHEM CTR LUND,POB 124,S-22100 LUND,SWEDEN. RI Lee, Timothy/K-2838-2012 NR 39 TC 21 Z9 21 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 1995 VL 103 IS 1 BP 266 EP 273 DI 10.1063/1.469639 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RF726 UT WOS:A1995RF72600029 ER PT J AU WETZEL, PJ BOONE, A AF WETZEL, PJ BOONE, A TI A PARAMETERIZATION FOR LAND-ATMOSPHERE-CLOUD EXCHANGE (PLACE) - DOCUMENTATION AND TESTING OF A DETAILED PROCESS MODEL OF THE PARTLY CLOUDY BOUNDARY-LAYER OVER HETEROGENEOUS LAND SO JOURNAL OF CLIMATE LA English DT Article ID SOIL-MOISTURE; SURFACE PROCESSES; CUMULUS ONSET; FLUXES; HEAT; EVAPOTRANSPIRATION; DYNAMICS; FIELD; FIFE; PHOTOSYNTHESIS AB This paper presents a general description of, and demonstrates the capabilities of, the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE). The PLACE model is a detailed process model of the partly cloudy atmospheric boundary layer and underlying heterogeneous land surfaces. In its development, particular attention has been given to three of the model's subprocesses: the prediction of boundary layer cloud amount, the treatment of surface and soil subgrid heterogeneity, and the liquid water budget. The model includes a three-parameter nonprecipitating cumulus model that feeds back to the surface and boundary layer through radiative effects. Surface heterogeneity in the PLACE model is treated both statistically and by resolving explicit subgrid patches. The model maintains a vertical column of liquid water that is divided into seven reservoirs, from the surface interception store down to bedrock. Five single-day demonstration cases are presented, in which the PLACE model was initialized, run, and compared to field observations from four diverse sites. The model is shown to predict cloud amount well in these cases while predicting the surface fluxes with similar accuracy. A slight tendency to underpredict boundary layer depth is noted in all cases. Sensitivity tests were also run using anemometer-level forcing provided by the Project for Inter-comparison of Land-surface Parameterization Schemes (PILPS). The purpose is to demonstrate the relative impact of heterogeneity of surface parameters on the predicted annual mean surface fluxes. Significant sensitivity to subgrid variability of certain parameters is demonstrated, particularly to parameters related to soil moisture. A major result is that the PLACE-computed impact of total (homogeneous) deforestation of a rain forest is comparable in magnitude to the effect of imposing heterogeneity of certain surface variables, and is similarly comparable to the overall variance among the other PILPS participant models. Were this result to be bourne out by further analysis, it would suggest that today's average land surface parameterization has little credibility when applied to discriminating the local impacts of any plausible future climate change. RP WETZEL, PJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE DYANAM & PRECIPITAT BRANCH,CODE 912,GREENBELT,MD 20771, USA. NR 58 TC 76 Z9 76 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1995 VL 8 IS 7 BP 1810 EP 1837 DI 10.1175/1520-0442(1995)008<1810:APFLCE>2.0.CO;2 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK219 UT WOS:A1995RK21900006 ER PT J AU SCOTT, R KOSTER, RD ENTEKHABI, D SUAREZ, MJ AF SCOTT, R KOSTER, RD ENTEKHABI, D SUAREZ, MJ TI EFFECT OF A CANOPY INTERCEPTION RESERVOIR ON HYDROLOGICAL PERSISTENCE IN A GENERAL-CIRCULATION MODEL SO JOURNAL OF CLIMATE LA English DT Note ID SIMPLE BIOSPHERE MODEL AB Using decadal GCM simulations, the effects of a SVAT (Surface-Vegetation-Atmosphere-Transfer) and a ''bucket'' land surface parameterization on simulated hydrological persistence are contrasted. The bucket model promotes persistence, as measured by the one-month-lagged autocorrelations of precipitation and evaporation, relative to the SVAT model, particularly in the Tropics. An additional simulation shows that despite the many complexities incorporated into the SVAT model's evaporation formulation, it is the canopy interception reservoir alone that explains most of the difference. Water that evaporates from this reservoir bypasses bare soil and stomatal resistances. The interception reservoir thus acts as a short circuit in the soil and vegetation resistance network that decreases hydrological persistence by reducing the residence time of surface moisture. C1 MIT, RALPH M PARSONS LAB, DEPT CIVIL & ENVIRONM ENGN, CAMBRIDGE, MA 02139 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 15 TC 24 Z9 24 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1995 VL 8 IS 7 BP 1917 EP 1922 DI 10.1175/1520-0442(1995)008<1917:EOACIR>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RK219 UT WOS:A1995RK21900012 ER PT J AU WARD, GT HERRMANN, DJ HILLBERRY, BM AF WARD, GT HERRMANN, DJ HILLBERRY, BM TI FATIGUE-LIFE BEHAVIOR AND MATRIX FATIGUE-CRACK SPACING IN UNNOTCHED SCS-6/TIMETAL(R)21S METAL-MATRIX COMPOSITES SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE FATIGUE; TITANIUM MATRIX; SILICON-CARBIDE FIBERS; UNNOTCHED; CROSS-PLY LAMINATES; MATRIX FATIGUE CRACK SPACING ID FIBER; FRACTURE AB Fatigue tests of the SCS-6/Timetal(R)21S composite system were performed to characterize the fatigue behavior for unnotched specimens. The stress-life behavior of the unnotched [0/90](2S) laminates was investigated for stress ratios of R = 0.1 and R = 0.3. No difference in fatigue lives was observed when comparing the two stress ratios on a stress-range basis. The unnotched SCS-6/Timetal 21S composites had shorter fatigue lives than those reported in the literature for the SCS-6/Ti-15-3 composites; however, the neat Timetal 21S matrix material had a longer fatigue life than those reported for the neat Ti-15-3. Multiple matrix crack initiation sites were observed throughout the composite, as well as evenly spaced transverse fatigue cracks along the length of the specimens. The spacing between fatigue cracks was investigated, as were the effects of surface cracking on composite stiffness. C1 NASA,LANGLEY RES CTR,MAT & MECH BRANCH,HAMPTON,VA 23681. RP WARD, GT (reprint author), PURDUE UNIV,SCH MECH ENGN,W LAFAYETTE,IN 47907, USA. NR 16 TC 6 Z9 6 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD JUL PY 1995 VL 17 IS 3 BP 205 EP 211 PG 7 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA RJ652 UT WOS:A1995RJ65200004 ER PT J AU COHEN, D HYER, MW SHUART, MJ GRIFFIN, OH PRASAD, C YALAMANCHILI, SR AF COHEN, D HYER, MW SHUART, MJ GRIFFIN, OH PRASAD, C YALAMANCHILI, SR TI FAILURE CRITERION FOR THICK MULTIFASTENER GRAPHITE-EPOXY COMPOSITE JOINTS SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE COMPOSITE AVERAGE STRESS CRITERION; MULTIFASTENER JOINTS; SINGLE-FASTENER JOINTS; MATERIAL STRENGTH; MAXIMUM STRAIN CRITERION ID PIN LOADED HOLES; LAMINATED COMPOSITES; STRENGTH AB A method for accurately predicting the strength of multifastener, thick composite joints is discussed. The method is based on the average stress criterion applied around the hole circumference. Basic laminate strength data are obtained from single-fastener and reduced-section notched specimens. Using ABAQUS finite element analyses (FEA), the stress-field distribution around the fastener-loaded hole in both the single-fastener and multifastener joints is determined. The single-fastener test data in conjunction with this FEA and the average stress criterion are then used to predict the multifastener joint strength. Multifastener joint strength of three different laminate lay-ups is predicted to within 1% accuracy. However, the results show that the average stress criterion cannot accurately predict the location of failure initiation. In the current investigation, the maximum strain criterion is used to locate possible sites of failure initiation. When this information is used in conjunction with the average stress criterion, the predicted multifastener joint strength based on single-fastener net-tension data is reasonably accurate. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061. NASA,LANGLEY RES CTR,DIV STRUCT MECH,HAMPTON,VA 23681. ANALYT SERV & MAT INC,HAMPTON,VA 23681. GM CORP,TRUCK ENGN,WARREN,MI 48091. RP COHEN, D (reprint author), ALLIANT TECHNOSYST INC,BALL AEROSP SYST GRP,POB 98,MAGNA,UT 84044, USA. NR 17 TC 9 Z9 9 U1 0 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD JUL PY 1995 VL 17 IS 3 BP 237 EP 248 PG 12 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA RJ652 UT WOS:A1995RJ65200009 ER PT J AU HARARI, I TURKEL, E AF HARARI, I TURKEL, E TI ACCURATE FINITE-DIFFERENCE METHODS FOR TIME-HARMONIC WAVE-PROPAGATION SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID SCHEMES; REFLECTION; EQUATION AB Finite difference methods for solving problems of time-harmonic acoustics are developed and analyzed. Multi-dimensional inhomogeneous problems with variable, possibly discontinuous, coefficients are considered, accounting for the effects of employing nonuniform grids. A weighted-average representation is less sensitive to transition in wave resolution (due to variable wave numbers or non-uniform grids) than the standard pointwise representation. Further enhancement in method performance is obtained by basing the stencils on generalizations of Padi! approximation, or generalized definitions of the derivative, reducing spurious dispersion, anisotropy, and reflection, and by improving the representation of source terms. The resulting schemes have fourth-order accurate local truncation error on uniform grids and third order in the nonuniform case. Guidelines for discretization pertaining to grid orientation and resolution are presented. (C) 1995 Academic Press, Inc. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681. RP HARARI, I (reprint author), TEL AVIV UNIV,RAMAT AVIV,ISRAEL. RI Turkel, Eli/F-6297-2011 OI Turkel, Eli/0000-0003-4273-0303 NR 20 TC 75 Z9 77 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL PY 1995 VL 119 IS 2 BP 252 EP 270 DI 10.1006/jcph.1995.1134 PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RG565 UT WOS:A1995RG56500005 ER PT J AU TIDRIRI, MD AF TIDRIRI, MD TI DOMAIN DECOMPOSITION FOR COMPRESSIBLE NAVIER-STOKES EQUATIONS WITH DIFFERENT DISCRETIZATIONS AND FORMULATIONS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article AB The purpose of this work is to couple different numerical models and approximations for the calculation of high speed external flows governed by the compressible Navier-Stokes equations. The proposed coupling is achieved by the boundary conditions, which impose viscous fluxes and friction forces on the body for the calculation of the global external flow and which impose Dirichlet type boundary conditions on the interface for the local model. (C) 1995 Academic Press, Inc. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. NR 14 TC 16 Z9 16 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL PY 1995 VL 119 IS 2 BP 271 EP 282 DI 10.1006/jcph.1995.1135 PG 12 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RG565 UT WOS:A1995RG56500006 ER PT J AU CHANG, SC AF CHANG, SC TI THE METHOD OF SPACE-TIME CONSERVATION ELEMENT AND SOLUTION ELEMENT - A NEW APPROACH FOR SOLVING THE NAVIER-STOKES AND EULER EQUATIONS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID FINITE-DIFFERENCE; LAWS; SCHEMES AB A new numerical framework for solving conservation laws is being developed. This new framework differs substantially in both concept and methodology from the well-established methods, i.e., finite difference, finite volume, finite element, and spectral methods. It is conceptually simple and designed to overcome several key limitations of the above traditional methods. A two-level scheme for solving the convection-diffusion equation partial derivative u/partial derivative t + a partial derivative u/partial derivative x - mu partial derivative(2)u/partial derivative x(2) = 0 (mu greater than or equal to 0) is constructed and used to illuminate major differences between the present method and those mentioned above. This explicit scheme, referred to as the a-mu, scheme, has two independent marching variables u eta and (u(x))eta which are the numerical analogues of u and partial derivative u/partial derivative x at (j, n), respectively. The a-mu scheme has the unusual property that its stability is limited only by the CFL condition, i.e., it is independent of mu. Also it ca n be shown that the amplification factors of the a-mu scheme are identical to those of the Leapfrog scheme if mu = 0, and to those of the DuFort-Frankel scheme if a = 0. These coincidences are unexpected because the a-mu scheme and the above classical schemes are derived from completely different perspectives, and the a-mu scheme does not reduce to the above classical schemes in the limiting cases. The a-mu scheme is extended to solve the 1D time-dependent Navier-Stokes equations of a perfect gas. Stability of this explicit solver also is limited only by the CFL condition. In spite of the fact that it does not use (i) any techniques related to the high-resolution upwind methods, and (ii) any ad hoc parameter, the current Navier-Stokes solver is capable of generating highly accurate shock tube solutions. Particularly, for high-Reynolds-number flows, shock discontinuities can be resolved within one mesh interval. The inviscid (mu = O) a-mu scheme is reversible in time. It also is neutrally stable, i.e., free from numerical dissipation. Such a scheme generally cannot be extended to solve the Euler equations. Thus, the inviscid version is modified. Stability of this modified scheme, referred to as the a-E scheme, is limited by the CFL condition and 0 less than or equal to epsilon less than or equal to 1, where epsilon is a special parameter that controls numerical dissipation. Moreover, if epsilon = 0, the amplification factors of the a-epsilon scheme are identical to those of the Leapfrog scheme, which has no numerical dissipation. On the other hand, if epsilon = 1, the two amplification factors of the a-epsilon scheme become the same function of the Courant number and the phase angle. Unexpectedly, this function also is the amplification factor of the highly diffusive Lax scheme. Note that, because the Lax scheme is very diffusive and it uses a mesh that is staggered in time, a two-level scheme using such a mesh is often associated with a highly diffusive scheme. The a-epsilon scheme, which also uses a mesh staggering in time, demonstrates that it can also be a scheme with no numerical dissipation. The Euler extension of the a-epsilon scheme has stability conditions similar to those of the a-epsilon scheme itself. It has the unusual property that numerical dissipation at all mesh points can be controlled by a set of local parameters. Moreover, it is capable of generating accurate shock tube solutions with the CFL number ranging from close to 1 to 0.022 (C) 1995 Academic Press, Inc. RP CHANG, SC (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 30 TC 206 Z9 268 U1 2 U2 20 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL PY 1995 VL 119 IS 2 BP 295 EP 324 DI 10.1006/jcph.1995.1137 PG 30 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RG565 UT WOS:A1995RG56500008 ER PT J AU LEE, J LEE, DJ LEE, JH AF LEE, J LEE, DJ LEE, JH TI ON THE MECHANISM OF OSCILLATION IN A SIMULATED FLOATING-ZONE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID TENSION DRIVEN FLOW; THERMOCAPILLARY CONVECTION; MARANGONI-CONVECTION; REDUCED GRAVITY; SURFACE; STEADY AB An experimental study is performed to investigate the unstable oscillatory thermocapillary flow and its associate temperature characteristics in a simulated floating zone. Oscillatory flow, which is three dimensional and has an azimuthal directional velocity, appears when the Marangoni number is greater than a certain critical value. The flow patterns in the liquid zone are classified with mode numbers according to the oscillatory flow characteristics. It is determined that the mode depends on the aspect ratio but not on Marangoni number. Also, the thermal oscillation frequency is observed to be equal to the rotation frequency of the flow. Flow oscillation, temperature oscillation and the free surface deformation are found to be closely coupled and these frequencies are equal. C1 GOLDSTAR LTD,LIVING SYST LAB,SEOUL,SOUTH KOREA. NASA,LEWIS RES CTR,MICROGRAV BRANCH,CLEVELAND,OH 44135. RP LEE, J (reprint author), YONSEI UNIV,DEPT MECH ENGN,SEOUL 120749,SOUTH KOREA. NR 14 TC 14 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 1995 VL 152 IS 4 BP 341 EP 346 DI 10.1016/0022-0248(95)00098-4 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA RL343 UT WOS:A1995RL34300017 ER PT J AU ROKHLIN, SI CHU, YC BAAKLINI, GY AF ROKHLIN, SI CHU, YC BAAKLINI, GY TI ASSESSMENT OF DAMAGE IN CERAMICS AND CERAMIC-MATRIX COMPOSITES USING ULTRASONIC TECHNIQUES SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 39th International Gas Turbine and Aeroengine Congress and Exposition CY JUN 13-16, 1994 CL THE HAGUE, NETHERLANDS ID THERMAL-SHOCK; BEHAVIOR AB This paper addresses the application of ultrasonic methods to damage assessment in ceramics and ceramic matrix composites. It focuses on damage caused by thermal shock and oxidation at elevated temperatures. The damage-induced changes in elastic constants and elastic anisotropy are determined by measuring the velocities of ultrasonic waves in different propagation directions within the sample. Thermal shock damage measurement is performed in ceramic samples of reaction bonded silicon nitride (RBSN) and aluminum oxide. Thermal shock treatment from different temperatures up to 1000 degrees C is applied to produce the microcracks. Both surface and bulk ultrasonic wave methods are used to correlate the change of elastic constants to microstructural degradation and to determine the change in elastic anisotropy induced by microcrack damage. Oxidation damage is studied in silicon carbide fiber/reaction bonded silicon nitride matrix (SCS-6/RBSN) composites. The oxidation is done by exposing the samples in a flowing oxygen environment at elevated temperatures, up to 1400 degrees C, for 100 hours. Significant changes of ultrasonic velocities were observed for composites before and after oxidation. The elastic constants of the composites were determined from the measured velocity data. The Young's modulus in the fiber direction as obtained from ultrasonic measurements decreases significantly at 600 degrees C but retains its original value at temperatures above 1200 degrees C. This agrees well with the results of destructive tests by other authors. The transverse longitudinal and shear moduli obtained from ultrasonic measurements decrease continually until 1200 degrees C. The results of this work show that the damage-induced anisotropy in both ceramics and ceramic matrix composites can be determined successfully by ultrasonic methods. This suggests the possibility of assessing damage severity using ultrasonic techniques. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP ROKHLIN, SI (reprint author), OHIO STATE UNIV,DEPT WELDING ENGN,COLUMBUS,OH 43210, USA. NR 15 TC 1 Z9 1 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JUL PY 1995 VL 117 IS 3 BP 417 EP 423 DI 10.1115/1.2814113 PG 7 WC Engineering, Mechanical SC Engineering GA RR457 UT WOS:A1995RR45700006 ER PT J AU JOHNSEN, BP CRUSE, TA MILLER, RA BRINDLEY, WJ AF JOHNSEN, BP CRUSE, TA MILLER, RA BRINDLEY, WJ TI COMPRESSIVE FATIGUE OF A PLASMA-SPRAYED ZRO2-8WT-PERCENT-Y2O3 AND ZRO2-10WT-PERCENT-NICRALCOY TTBC SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID PREDICTION MODEL DEVELOPMENT AB High cycle ( > 10(6) cycles) fatigue (HCF) behavior of thick thermal barrier coatings (TTBC's) was examined for applied stresses near the compressive strength of the material. Test data were obtained on four coating systems: two base materials in the unsealed and CrO2 dip sealed conditions. Free standing tubular specimens were evaluated. The data show that compressive fatigue limits exist for the four coating systems at room temperature (RT) and sealing with CrO2 improves RT fatigue life. Test results also show the ratio of the peak cyclic stress, at 10(5) cycles, to ultimate compressive strength (UCS) of the Yttria Stabilized Zirconia (YSZ) tubular specimens approaches 0.90 at R = 0.6 (R = minimum/maximum compressive stress). Residual UCS increases were observed after fatigue run-outs at elevated temperatures (5 at 700 degrees C and 1 at 400 degrees C) for both YSZ and the cermet. Ratchetting with cyclic hardening was observed during fatigue with deformation occurring primarily in the initial portion of the high cycle fatigue life of the specimens. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP JOHNSEN, BP (reprint author), VANDERBILT UNIV,DEPT MECH ENGN,NASHVILLE,TN 37235, USA. NR 14 TC 16 Z9 16 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD JUL PY 1995 VL 117 IS 3 BP 305 EP 310 DI 10.1115/1.2804544 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA RQ710 UT WOS:A1995RQ71000009 ER PT J AU SEON, J FRANK, LA LAZARUS, AJ LEPPING, RP AF SEON, J FRANK, LA LAZARUS, AJ LEPPING, RP TI SURFACE-WAVES ON THE TAILWARD FLANKS OF THE EARTHS MAGNETOPAUSE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID KELVIN-HELMHOLTZ INSTABILITY; LATITUDE BOUNDARY-LAYER; ELECTRIC-FIELD EVIDENCE; INTERPLANETARY MAGNETIC-FIELD; FLUX-TRANSFER EVENTS; VISCOUS INTERACTION; MAGNETOSPHERIC BOUNDARY; PARTICLE OBSERVATIONS; SEMIANNUAL VARIATION; GEOMAGNETIC ACTIVITY AB Forty-three examples of ISEE 1 tailward flank side magnetopause crossings are examined and directly compared with upstream solar wind parameters. The crossings are classified into two groups. In the first group, a few sudden magnetopause crossings are observed, whereas repeated magnetopause crossings and oscillatory motions, often with boundary layer signatures, are observed in the second group. These distinctive characteristics of the two groups are interpreted in terms of the surface waves due to the Kelvin-Helmholtz instability. It is found that low solar wind speed tends to favor characteristics of the first group, whereas high solar wind speed yields those of the second group. However, no evident correlations between the groups and the interplanetary magnetic field directions are found. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP SEON, J (reprint author), UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242, USA. RI Seon, Jongho/E-2363-2013 NR 60 TC 33 Z9 33 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 11907 EP 11922 DI 10.1029/94JA03314 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700008 ER PT J AU SUESS, ST MCCOMAS, DJ BAME, SJ GOLDSTEIN, BE AF SUESS, ST MCCOMAS, DJ BAME, SJ GOLDSTEIN, BE TI SOLAR-WIND EDDIES AND THE HELIOSPHERIC CURRENT SHEET SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID VELOCITY FLUCTUATIONS; OUTER HELIOSPHERE; SECTOR STRUCTURE; STREAMER BELT; VORTEX STREET; ALFVEN WAVES; ULYSSES; EVOLUTION; SYSTEM; MODEL AB Ulysses has collected data between 1 and 5 AU during, and just following solar maximum, when the heliospheric current sheet (HCS) can be thought of as reaching its maximum tilt and being subject to the maximum amount of turbulence in the solar wind. The Ulysses solar wind plasma instrument measures the vector velocity and can be used to estimate the flow speed and direction in turbulent ''eddies'' in the solar wind that are a fraction of an astronomical unit in size and last (have either a turnover or dynamical interaction time of) several hours to more than a day. Here, in a simple exercise, these solar wind eddies at the HCS are characterized using Ulysses data. This character is then used to define a model flow field with eddies that is imposed on an ideal HCS to estimate how the RCS will be deformed by the flow. This model inherently results in the complexity of the HCS increasing with heliocentric distance, but the result is a measure of the degree to which the observed change in complexity is a measure of the importance of solar wind flows in deforming the HCS. By comparison with randomly selected intervals not located on the RCS, it appears that eddies on the HCS are similar to those elsewhere at this time during the solar cycle, as is the resultant deformation of the interplanetary magnetic field (IMF). The IMF deformation is analogous to what is often termed the ''random walk'' of interplanetary magnetic field lines. C1 LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NASA, JET PROP LAB, PASADENA, CA USA. RP SUESS, ST (reprint author), NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, MS ES82, HUNTSVILLE, AL 35801 USA. NR 34 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 12261 EP 12273 DI 10.1029/95JA00764 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700036 ER PT J AU SRIVASTAVA, KM TSURUTANI, BT SAUER, K SHARMA, V AF SRIVASTAVA, KM TSURUTANI, BT SAUER, K SHARMA, V TI PARTICLE INTERACTIONS WITH OBLIQUELY PROPAGATING MAGNETOSONIC WAVES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID COMET GIACOBINI-ZINNER; WATER GROUP IONS; PICKUP IONS; VELOCITY DISTRIBUTIONS; SOLAR-WIND; BOW-SHOCK; HALLEY; PROTONS; DIFFUSION; UPSTREAM AB Four cases of nonlinear obliquely propagating magnetosonic (MS) waves are considered using a test particle approach for particles interaction with (1) monochromatic waves propagating both sunward and antisunward, (2) monochromatic waves propagating unidirectionally toward the Sun, (3) a broad band spectrum, propagating both sunward and antisunward, and (4) a broadband spectrum, propagating sunward only. As the solar wind decelerates rapidly inside the bow shock, the interplanetary magnetic field (IMF) increases. Calculations have been performed taking into account such a spatially dependent IMF (based on observations). We find that significant particle acceleration is achieved for both the monochromatic wave and the ''turbulent'' MS waves, for oblique propagation (angles between the interplanetary magnetic field and the propagation vector larger than 30 degrees). This is due to the fact that at oblique angles resonance width increases. We have compared the relative acceleration of particles for the four cases. Pitch angle scattering and acceleration of particles are found to be much larger in the case of sunward and antisunward propagating waves than those for the sunward waves only. This is due to larger relative phase velocities in the two cases. Also, acceleration of particles is less in the case of a uniform magnetic field than that in the case of spatially increasing magnetic field. The particles get more pitch angle scattered and accelerated in the latter case. C1 INST SYST STUDIES & ANAL,DEF SCI RES ORG,DELHI 110054,INDIA. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP SRIVASTAVA, KM (reprint author), MAX PLANCK INST EXTRATERR PHYS,RODOWER CHAUSSEE 5,D-12498 BERLIN,GERMANY. NR 20 TC 0 Z9 0 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 12275 EP 12284 DI 10.1029/95JA00769 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700037 ER PT J AU FARRUGIA, CJ OSHEROVICH, VA BURLAGA, LF AF FARRUGIA, CJ OSHEROVICH, VA BURLAGA, LF TI MAGNETIC-FLUX ROPE VERSUS THE SPHEROMAK AS MODELS FOR INTERPLANETARY MAGNETIC CLOUDS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR ENERGETIC PARTICLES; HYDROMAGNETIC CLOUDS; FIELD STRUCTURE; DYNAMICS; MAGNETOSPHERE; VOYAGER; FLARES AB Magnetic clouds form a subset of interplanetary ejecta with well-defined magnetic and thermodynamic properties. Observationally, it is well established that magnetic clouds expand as they propagate antisunward. The aim of this paper is to compare and contrast two models which have been proposed for the global magnetic field line topology of magnetic clouds: a magnetic flux tube geometry, on the one hand, and a spheromak geometry (including possible higher multiples), on the other. Traditionally, the magnetic structure of magnetic clouds has been modeled by force-free configurations. In a first step, we therefore analyze the ability of static force-free models to account for the asymmetries observed in the magnetic field profiles of magnetic clouds. For a cylindrical flux tube the magnetic field remains symmetric about closest approach to the magnetic axis on all spacecraft orbits intersecting it, whereas in a spheromak geometry one can have asymmetries in the magnetic field signatures along some spacecraft trajectories. The duration of typical magnetic cloud encounters at 1 AU (1 to 2 days) is comparable to their travel time from the Sun to 1 AU and thus magnetic clouds should be treated as strongly nonstationary objects. In a second step, therefore, we abandon the static approach and model magnetic clouds as self-similarly evolving MHD configurations. In our theory, the interaction of the expanding magnetic cloud with the ambient plasma is taken into account by a drag force proportional to the density and the velocity of expansion. Solving rigorously the full set of MHD equations, we demonstrate that the asymmetry in the magnetic signature may arise solely as a result of expansion. Using asymptotic solutions of the MHD equations, we least squares fit both theoretical models to interplanetary data. We find that while the central part of the magnetic cloud is adequately described by both models, the ''edges'' of the cloud data are modeled better by the magnetic flux tube. Further comparisons of the two models necessarily involve thermodynamic properties, since real magnetic configurations are never exactly force-free and gas pressure plays an essential role. We consider a polytropic gas. Our theoretical analysis shows that the self-similar expansion of a magnetic flux tube requires the polytropic index gamma to be less than unity. For the spheromak, however, self-similar, radially expanding solutions are known only for gamma equal to 4/3. This difference, therefore, yields a good way of distinguishing between the two geometries. It has been shown recently (Osherovich et al., 1993a) that the polytropic relationship is applicable to magnetic clouds and that the corresponding polytropic index is similar to 0.5. This observational result is consistent with the self-similar model of the magnetic flux rope but is in conflict with the self-similar spheromak model. C1 NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX, GREENBELT, MD 20771 USA. NR 41 TC 85 Z9 89 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-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 12293 EP 12306 DI 10.1029/95JA00272 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700039 ER PT J AU OSHEROVICH, VA FARRUGIA, CJ BURLAGA, LF AF OSHEROVICH, VA FARRUGIA, CJ BURLAGA, LF TI NONLINEAR EVOLUTION OF MAGNETIC-FLUX ROPES .2. FINITE-BETA PLASMA SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CLOUDS; MODELS; MAGNETOTAIL AB In this second paper on the evolution of magnetic flux ropes we study the effects of gas pressure. We assume that the energy transport is described by a polytropic relationship and reduce the set of ideal MHD equations to a single, second-order, nonlinear, ordinary differential equation for the evolution function. For this conservative system we obtain a first integral of motion. To analyze the possible motions, we use a mechanical analogue-a one-dimensional, nonlinear oscillator. We find that the effective potential for such an oscillator depends on two parameters: the polytropic index gamma and a dimensionless quantity kappa the latter being a function of the plasma beta, the strength of the azimuthal magnetic field relative to the axial field of the flux rope, and gamma. Through a study of this effective potential we classify all possible modes of evolution of the system. In the main body of the paper, we focus on magnetic flux ropes whose field and gas pressure increase steadily towards the symmetry axis. In this case, for gamma > 1 and all values of kappa, only oscillations are possible. For gamma < 1, however, both oscillations and expansion are allowed. For gamma < 1 and kappa below a critical value, the energy of the nonlinear oscillator determines whether the flux rope will oscillate or expand to infinity. For gamma < 1 and kappa above critical, however, only expansion occurs. Thus by increasing kappa while keeping gamma fixed (<1), a phase transition occurs at kappa = kappa(critical) and the oscillatory mode disappears. We illustrate the above theoretical considerations by the example of a flux rope of constant field line twist evolving self-similarly. For this example, we present the full numerical MHD solution. In an appendix to the paper we catalogue all possible evolutions when (1) either the magnetic field or (2) the gas pressure decreases monotonically toward the axis. We find that in these cases critical conditions can occur for gamma > 1. While in most cases the flux rope collapses, there are notable exceptions when, for certain ranges of kappa and gamma, collapse may be averted. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX, GREENBELT, MD 20771 USA. NR 24 TC 43 Z9 45 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 12307 EP 12318 DI 10.1029/95JA00273 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700040 ER PT J AU GOLDSTEIN, ML AF GOLDSTEIN, ML TI ALFVENIC DISTURBANCES IN THE EQUATORIAL SOLAR-WIND WITH A SPIRAL MAGNETIC-FIELD - COMMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID EVOLUTION RP GOLDSTEIN, ML (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. RI Goldstein, Melvyn/B-1724-2008 NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1995 VL 100 IS A7 BP 12319 EP 12320 DI 10.1029/95JA01212 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG737 UT WOS:A1995RG73700041 ER PT J AU FISHER, S SCHULTZ, KI TAYLOR, LW AF FISHER, S SCHULTZ, KI TAYLOR, LW TI VIBRATIONS OF THE LOW-POWER ATMOSPHERIC COMPENSATION EXPERIMENT SATELLITE SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB The Low Power Atmospheric Compensation (LACE) satellite dynamics experiment has measured vibrations of an orbiting satellite from a ground site and has observed the excitation of satellite vibrations by a sequence of boom movements. The preprogrammed boom movements were initiated by commands from a ground control site and observed by the Massachusetts Institute of Technology Lincoln Laboratory Firepond laser radar facility located in Westford, Massachusetts. In the tests, a narrow-band heterodyne CO2 laser radar, operating at a wavelength of 10.6 mu m, detected vibration-induced differential Doppler signatures of the LACE satellite. Augmentation of vibration amplitudes was achieved through timing of repeated boom movements. Evidence of open loop vibration damping by this method of repeated boom movements was also obtained, although the data were not conclusive since only a single attempt at open-loop damping was observed. The tests have demonstrated the feasibility and advantages of using relatively low cost ground-based observation techniques for vibration measurements and health monitoring of orbiting structures and for improving the accuracy of mathematical models for the structural dynamics of light, flexible space structures. C1 MIT,LINCOLN LAB,DEPT AIR DEF TECHNOL,LEXINGTON,MA 02173. NASA,LANGLEY RES CTR,SPACECRAFT CONTROL BRANCH,HAMPTON,VA 23681. RP FISHER, S (reprint author), USN,RES LAB,DEPT SPACECRAFT ENGN,WASHINGTON,DC 20375, USA. NR 14 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 650 EP 656 DI 10.2514/3.21443 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700002 ER PT J AU HSIAO, MH HUANG, JK TAYLOR, LW AF HSIAO, MH HUANG, JK TAYLOR, LW TI OPTIMAL MODAL-SPACE CONTROLLER FOR STRUCTURAL DAMPING ENHANCEMENTS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB A stochastic optimum-based compensator is developed to enhance structural damping with collocated rate sensors/actuators. This controller is based on explicit solutions for the Riccati equations from a modal-space model. The performance of each controlled mode can be easily adjusted by the corresponding design parameters in the controller. NASA's Spacecraft Control Laboratory Experiment facility is used to demonstrate the effectiveness of this control design. A distributed-parameter model is first obtained by using Holzer's transfer matrix method and the corresponding modal parameters are identified. Then the distributed-parameter model is reduced to a finite-dimensional modal-space model for the controller design. Three torque actuators and three collocated rate sensors are used to suppress the vibration of the first five modes. Analytical and experimental results show that the proposed controller is effective in damping enhancements for large flexible structures. C1 OLD DOMINION UNIV,DEPT MECH ENGN,NORFOLK,VA 23529. NASA,LANGLEY RES CTR,DIV GUIDANCE & CONTROL,HAMPTON,VA 23681. RP HSIAO, MH (reprint author), NATL TAIWAN INST TECHNOL,DEPT MECH ENGN,TAIPEI 10772,TAIWAN. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 657 EP 663 DI 10.2514/3.21444 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700003 ER PT J AU DEMEO, ME GILBERT, MG SCOTT, MA LEPANTO, JA BAINS, EM JENSEN, MC AF DEMEO, ME GILBERT, MG SCOTT, MA LEPANTO, JA BAINS, EM JENSEN, MC TI HUMAN-IN-THE-LOOP EVALUATION OF REMOTE MANIPULATOR SYSTEM ACTIVE DAMPING AUGMENTATION SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID DESIGN AB This paper describes the application of controls-structures integration technology to benefit the on-orbit performance of the Space Shuttle remote manipulator system. Called active damping augmentation, the goal is to reduce the vibration decay time of the remote manipulator system following normal payload maneuvers and operations. Simulation of active damping augmentation was conducted in a real-time human-in-the-loop simulation of the remote manipulator system with the objective of obtaining qualitative and quantitative measurements of operational performance improvements from astronaut operators. Sensing of vibratory motions was simulated using a three-axis accelerometer mounted at the end of the lower boom of the remote manipulator system. The sensed motions were used in a feedback control law to generate commands to the remote manipulator system joint servo mechanisms which reduced the unwanted oscillations. Active damping of the remote manipulator system with an attached 3990-lb payload was successfully demonstrated. Six astronaut operators examined the performance of an active damping augmentation control law following payload maneuvers and Shuttle thruster firings. Significant reductions in the dynamic response were observed and investigation of performance benefits with heavier attached payloads was recommended. C1 NASA,LANGLEY RES CTR,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23681. NASA,LANGLEY RES CTR,SPACECRAFT CONTROLS BRANCH,HAMPTON,VA 23681. CHARLES STARK DRAPER LAB INC,DIV CONTROL & DECIS SYST,CAMBRIDGE,MA 02139. NASA,LYNDON B JOHNSON SPACE CTR,SIMULAT SYST BRANCH,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,DEPT SIMULAT DEV,HOUSTON,TX 77058. RP DEMEO, ME (reprint author), VIGYAN INC,MULTIDISCIPLINARY RES GRP,HAMPTON,VA, USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 689 EP 695 DI 10.2514/3.21448 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700007 ER PT J AU ZELENKA, RE YEE, Z ZIRKLER, A AF ZELENKA, RE YEE, Z ZIRKLER, A TI FLIGHT TEST OF RADAR ALTIMETER ENHANCEMENT FOR TERRAIN-REFERENCED GUIDANCE SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Aircraft operations at low altitude near the terrain require high pilot workload and are Inherently of high risk, even in fair weather and nonhostile environments. To reduce crew workload and allow safer flight in this regime, an automated guidance system was developed that presents a low altitude trajectory to the pilot on a helmet-mounted display. The guidance trajectory is generated by employing a digital terrain elevation map subject to mission requirements and aircraft performance limits. The flight envelope of this system is principally limited by accuracy in above ground level (AGL) positioning of the aircraft. Errors of the terrain elevation map and airborne navigation systems restricted flight to above 300 ft AGL. In this work, a Kalman filter state estimator has been developed that blends a radar altimeter with the airborne navigation and stored terrain elevation data for improved AGL positioning. This AGL altitude state estimator was integrated in a near terrain guidance system aboard a U.S. Army helicopter and flight tested in moderately rugged terrain over a variety of flight and system conditions. The minimum operating altitude of this terrain database referenced guidance system was reduced to 150 ft with the addition of this radar altimeter-based Kalman filter state estimator. C1 USA,COMMAND CONTROL & SYST INTEGRAT DIRECTORATE,FT MONMOUTH,NJ 07703. VITRON INC,EATONTOWN,NJ 07724. RP ZELENKA, RE (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 702 EP 708 DI 10.2514/3.21450 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700009 ER PT J AU CHEN, CW HUANG, JK JUANG, JN AF CHEN, CW HUANG, JK JUANG, JN TI IDENTIFICATION OF LINEAR STOCHASTIC-SYSTEMS THROUGH PROJECTION FILTERS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB A novel method is presented for identifying a state-space model and a state estimator for linear stochastic systems from input and output data. The method is primarily based on the relationship between the state-space model and the finite difference mode) of linear stochastic systems derived through projection filters. It is proved that least-squares identification of a finite difference model converges to the model derived from the projection filters. System pulse response samples are computed from the coefficients of the finite difference model. In estimating the corresponding state estimator gain, a z-domain method is used. First the deterministic component of the output is subtracted out, and then the state estimator gain is obtained by whitening the remaining signal. An experimental example is used to illustrate the feasibility of the method. C1 OLD DOMINION UNIV,DEPT MECH ENGN,NORFOLK,VA 23529. NASA,LANGLEY RES CTR,STRUCT DYNAM BRANCH,HAMPTON,VA 23681. RP CHEN, CW (reprint author), GEOPHYS & ENVIRONM RES CORP,MILLBROOK,NY 12545, USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 767 EP 772 DI 10.2514/3.21458 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700017 ER PT J AU CHENG, VHL LAM, T AF CHENG, VHL LAM, T TI AUTOMATIC GUIDANCE AND CONTROL FOR HELICOPTER OBSTACLE AVOIDANCE (VOL 17, PG 1252, 1994) SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Correction, Addition C1 STERLING SOFTWARE,PALO ALTO,CA 94303. RP CHENG, VHL (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JUL-AUG PY 1995 VL 18 IS 4 BP 935 EP 935 DI 10.2514/3.56684 PG 1 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RP557 UT WOS:A1995RP55700047 ER PT J AU UTKU, S KUO, CP GARBA, JA WADA, BK AF UTKU, S KUO, CP GARBA, JA WADA, BK TI SHAPE CONTROL OF INFLATABLE REFLECTORS SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article AB In this work studied are the means of maintaining the target design geometry of inflatable membranes that are used for low frequency antenna collectors. Considering the deviations from the target state as the linear combinations of a set of given n normalized undesirable displacement patterns (e.g., Fourier-Zernike functions), the linearized thin shell and membrane theories are used to obtain expressions for the components of the corresponding n number of induced macro strain states. Then the problems associated with the failure in implementing by piezofilm actuators all the components of the geometrically compatible macro strain states are studied. As a result of these studies several recommendations are given. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP UTKU, S (reprint author), DUKE UNIV,DEPT GEOL,DEPT CIVIL & ENVIRONM ENGN,BOX 90287,DURHAM,NC 27708, USA. NR 13 TC 5 Z9 6 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD JUL PY 1995 VL 6 IS 4 BP 550 EP 556 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA RN490 UT WOS:A1995RN49000012 ER PT J AU BISWAS, A WEBER, JKR NORDINE, PC AF BISWAS, A WEBER, JKR NORDINE, PC TI REMOVAL OF RESIDUAL CHROMIUM FROM ALUMINUM-OXIDE BY CONTAINERLESS LIQUID-PHASE PROCESSING SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB Verneuil sapphire was purified of Cr3+ by containerless melting and processing at ca. 2550 K in argon, dry air, and pure oxygen. Recovered material was examined by laser induced fluorescence and Raman spectroscopy. The Cr3+ fluorescence intensity decreased in processed specimens at rates proportional to the chromium concentration and p(O-2)(0.21) The initial chromium concentration was ca. 5 ppm and decreased by factors of ca. 50, 3000, and 2 X 10(5) after processing for 300 s in argon, air, and oxygen, respectively. Evidence is presented that the Cr3+ was removed predominantly as CrO2(g) and not by conversion to other oxidation states of chromium in the condensed phase. C1 CONTAINERLESS RES INC,EVANSTON,IL 60201. RP BISWAS, A (reprint author), CALTECH,JET PROP LAB,MICROGRAV RES GRP,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 20 TC 7 Z9 7 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1995 VL 10 IS 7 BP 1823 EP 1827 DI 10.1557/JMR.1995.1823 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA RE759 UT WOS:A1995RE75900032 ER PT J AU FLAUD, JM GROSSKLOSS, R RAI, SB STUBER, R DEMTRODER, W TATE, DA WANG, LG GALLAGHER, TF AF FLAUD, JM GROSSKLOSS, R RAI, SB STUBER, R DEMTRODER, W TATE, DA WANG, LG GALLAGHER, TF TI DIODE-LASER SPECTROSCOPY OF H-2 S-32 AROUND 0.82 MU-M SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID FAR-INFRARED SPECTRUM; HYDROGEN-SULFIDE; ROTATIONAL-CONSTANTS; (H2S)-S-33; WATER; NU-2; H2S AB The absorption spectrum of H2S has been investigated in the range 11 930-12 300 cm(-1) by means of an externally frequency modulated tunable diode laser and a multipath absorption cell. Approximately 290 lines have been assigned to rovibrational transitions of the 3 nu(1) + 2 nu(3) and 2 nu(1) + 3 nu(3) bands which are in strong interaction. The rotational structure of the corresponding excited vibrational states has been satisfactorily reproduced using a Hamiltonian model which takes explicitly into account the strong Coriolis interaction coupling the levels of(302) with those of (203), as well as weaker anharmonic and Coriolis-type interactions between the levels of(302) and (203) and those of (222) and (321). Precise band centers and rotational and coupling constants have been derived and the local mode behavior of the energy levels was clearly observed. (C) 1995 Academic Press, Inc. C1 UNIV KAISERSLAUTERN,FACHBEREICH PHYS,D-67653 KAISERSLAUTERN,GERMANY. COLBY COLL,WATERVILLE,ME 04901. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV VIRGINIA,CHARLOTTESVILLE,VA 22901. RP FLAUD, JM (reprint author), UNIV PARIS 06,PHYS MOLEC & APPLICAT LAB,CNRS,BTE 76,4 PL JUSSIEU,F-75252 PARIS 05,FRANCE. RI Rai, Shyam/D-4689-2013 NR 23 TC 25 Z9 27 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUL PY 1995 VL 172 IS 1 BP 275 EP 281 DI 10.1006/jmsp.1995.1175 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA RG022 UT WOS:A1995RG02200025 ER PT J AU KORTE, JJ HODGE, JS AF KORTE, JJ HODGE, JS TI FLOW QUALITY OF HYPERSONIC WIND-TUNNEL NOZZLES DESIGNED USING COMPUTATIONAL FLUID-DYNAMICS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID NAVIER-STOKES PROCEDURE AB A new methodology has been demonstrated for designing the aerodynamic contour of hypersonic wind-tunnel nozzles using a computational fluid dynamics based design and optimization procedure, The new design method was based on a least-squares parabolized Navier-Stokes design and optimization procedure developed by the first author, An optimization problem was solved using the new design method to determine the aerodynamic contour that minimized the flowfield Mach-number variation, Two existing wind-tunnel nozzles were remachined with the new aerodynamic contours designed with this procedure. The flow quality of the nozzles was examined using detailed pitot-pressure profiles measured in the test section, The flow quality of the remachined nozzles showed an improvement over a recently designed and constructed wind-tunnel nozzle based on the classical method-of-characteristics boundary-layer correction technique, However, the how quality was not as uniform as predicted, because of disturbances emanating from mechanical joints. The pitot-pressure profile away from the disturbance was extremely uniform, significantly better than for previous wind-tunnel nozzles at similar Mach numbers, demonstrating the importance of using a computational-based design procedure for wind-tunnel nozzles that have to operate with thick boundary layers. C1 NASA,LANGLEY RES CTR,DIV GAS DYNAM,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681. RP KORTE, JJ (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH & ACOUST,MULTIDISCIPLINARY DESIGN OPTIMIZAT BRANCH,HAMPTON,VA 23681, USA. NR 29 TC 1 Z9 3 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 569 EP 580 DI 10.2514/3.26655 PG 12 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600001 ER PT J AU BLANCHARD, RC NICHOLSON, JY RITTER, JR LARMAN, KT AF BLANCHARD, RC NICHOLSON, JY RITTER, JR LARMAN, KT TI ORBITAL ACCELERATION RESEARCH EXPERIMENT - CALIBRATION MEASUREMENTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The Orbital Acceleration Research Experiment (OARE), which has flown on STS-40, STS-50, and STS-58, contains a three-axis accelerometer with a single, nonpendulous, electrostatically suspended proofmass, which can resolve accelerations to the 10(-9) g level, The experiment also contains a full calibration station to permit in situ bias and scale-factor calibration, This on-orbit calibration capability eliminates the large uncertainty of ground-based calibrations encountered with accelerometers flown in the past on the Orbiter, and thus provides absolute acceleration measurement accuracy heretofore unachievable, This is the first time accelerometer scale-factor measurements have been performed on orbit, A detailed analysis of the calibration process is given, along with results of the calibration factors from the on-orbit OARE flight measurements on STS-58, In addition, the analysis of OARE flight-maneuver data used to validate the scale-factor measurements in the sensor's most sensitive range are also presented, Estimates on calibration uncertainties are discussed, These uncertainty estimates provides bounds on the STS-58 absolute acceleration measurements for future applications. C1 VIGYAN INC,HAMPTON,VA 23666. LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. RP BLANCHARD, RC (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 408A,HAMPTON,VA 23681, USA. NR 15 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 619 EP 626 DI 10.2514/3.26662 PG 8 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600008 ER PT J AU IH, CHC HILBERT, KB AF IH, CHC HILBERT, KB TI REDESIGN OF THE CELESTIAL PAINTING CONE CONTROL GAINS FOR THE GALILEO SPACECRAFT SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB During September and October 1991, pictures of the Gaspra asteroid and neighboring stars were taken by the Galileo Optical Navigation Team for the purpose of navigating the Galileo spacecraft for a successful Gaspra encounter. The star tracks in these pictures showed that the scan-platform celestial-pointing cone controller performed poorly in compensating for wobble-induced cone offsets. This poor performance is attributed to the very conservative cone control gains selected before launch. Thus the cone control gains were redesigned. The simulation results, the in-flight confirmation test, and the more recent optical-navigation pictures of the Ida asteroid all indicated that tremendous improvement in the scan-platform performance in compensating for the cone offsets has been achieved using the new gains, at no additional cost of the control torque. RP IH, CHC (reprint author), CALTECH,JET PROP LAB,AUTOMAT & CONTROL SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 4 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 627 EP 633 DI 10.2514/3.26663 PG 7 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600009 ER PT J AU FOSTER, CL TINKER, ML NURRE, GS TILL, WA AF FOSTER, CL TINKER, ML NURRE, GS TILL, WA TI SOLAR-ARRAY-INDUCED DISTURBANCE OF THE HUBBLE-SPACE-TELESCOPE POINTING SYSTEM SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The investigation of the vibrational disturbances of the Hubble Space Telescope that were discovered soon after deployment in orbit is described in detail. It was found that the disturbances were particularly evident during orbital day-night crossings, and that the magnitude of the disturbances was considerably larger than the design jitter requirement. This paper describes the process by which the vibrations were characterized and isolated to a particular mechanism, The analysis of the flight data and comparisons with computer simulation results showed that the source of the disturbances was the thermally driven deformation of the solar arrays In conjunction with frictional effects in the array mechanisms. The control system was successfully modified to attenuate the disturbances to tolerable levels pending mechanical and thermal redesign of the solar arrays, The new arrays were installed during the first Space Telescope servicing mission, and in combination with the enhanced control system algorithm reduced the disturbances to satisfactory levels. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV STRUCT ANAL,DYNAM & LOADS BRANCH,HUNTSVILLE,AL 35812. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT & DYNAM LAB,HUNTSVILLE,AL 35812. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV THERMAL & LIFE SUPPORT,SYST THERMAL DEISGN BRANCH,HUNTSVILLE,AL 35812. RP FOSTER, CL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV MECH SYST,SUPPORT EQUIPMENT BRANCH,HUNTSVILLE,AL 35812, USA. NR 16 TC 29 Z9 38 U1 2 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 634 EP 644 DI 10.2514/3.26664 PG 11 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600010 ER PT J AU JANKOVSKY, RS ARYA, VK KAZAROFF, JM HALFORD, GR AF JANKOVSKY, RS ARYA, VK KAZAROFF, JM HALFORD, GR TI STRUCTURALLY COMPLIANT ROCKET ENGINE COMBUSTION-CHAMBER - EXPERIMENTAL AND ANALYTICAL VALIDATION SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID ELEMENT AB A new, structurally compliant design for a rocket engine combustion chamber has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000% increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion-chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations. C1 UNIV AKRON,DEPT MATH SCI,AKRON,OH 44325. RP JANKOVSKY, RS (reprint author), NASA,LEWIS RES CTR,ON BOARD PROP BRANCH,CLEVELAND,OH 44135, USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 645 EP 652 PG 8 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600011 ER PT J AU RHODES, MD WILL, RW QUACH, CC AF RHODES, MD WILL, RW QUACH, CC TI VERIFICATION TESTS OF AUTOMATED ROBOTIC ASSEMBLY OF SPACE TRUSS STRUCTURES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A multidisciplinary program has been conducted at the Langley Research Center to develop operational procedures for supervised autonomous assembly of truss structures suitable for large-aperture antennas, The hardware and operations required to assemble a 102-member tetrahedral truss and attach 12 hexagonal panels were developed and evaluated. A brute-force automation approach was used to develop baseline assembly hardware and software techniques. However, as the system matured and operations were proven, upgrades were incorporated and assessed against the baseline test results. These upgrades included the use of distributed microprocessors to control dedicated end-effector operations, machine vision guidance for strut installation, and the use of an expert-system-based executive-control program. This paper summarizes the developmental phases of the program, the results of several assembly tests, and a series of proposed enhancements. No problems that mould preclude automated in-space assembly of truss structures have been encountered. The test system was developed at a breadboard level and continued development at an enhanced level is warranted. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,DIV INFORMAT & ELECTROMAGNET TECHNOL,HAMPTON,VA 23681. RP RHODES, MD (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT,MS 190,HAMPTON,VA 23681, USA. NR 13 TC 0 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 686 EP 696 DI 10.2514/3.26670 PG 11 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600016 ER PT J AU KASSEL, PC WORTMAN, JJ AF KASSEL, PC WORTMAN, JJ TI METAL-OXIDE-SILICON CAPACITOR DETECTORS FOR MEASURING MICROMETEOROID AND SPACE-DEBRIS FLUX SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Capacitor-type micrometeoroid flux detectors have been fabricated and tested. The detectors were of the metal-oxide-silicon type and were formed using standard silicon technology developed for fabricating microelectronic devices and circuits. The detectors were tested using an electrostatic accelerator and carbonyl iron projectiles ranging in size from 0.3 to 5.0 mu m in diameter (1 x 10(-13) to 5 x 10(-10) g) with velocities from 1 to 20 km/s, The detector operation was found to be reliable if the bias voltage was held above a threshold value that is necessary for a significant capacitor discharge. Variations of the bias voltage above the bias threshold did not appear to affect the detector sensitivity. An empirical relationship has been developed relating the sensitivity of the detectors to the detector thickness (dielectric plus top electrode) and the projectile diameter, velocity, and angle of impact. The mechanism responsible for the capacitor discharge appears to be the creation of charge carriers, followed by cascade ionization in the dielectric, caused by an impacting projectile. Once triggered, the discharge is then powered by the charge stored in the capacitor, which forms a plasma (spark) that causes a portion of the top metal electrode to vaporize, creating an open circuit at the impact site (i,e., the discharge self-extinguishes), which then allows the capacitor to recharge, The detector area lost as a result of impact damage is dependent on the discharge energy and is negligible for most applications. C1 N CAROLINA STATE UNIV,DEPT ELECT & COMP ENGN,RALEIGH,NC 27695. RP KASSEL, PC (reprint author), NASA,LANGLEY RES CTR,DIV EXPTL TESTING TECHNOL,ACOUST OPT & CHEM MEASUREMENT BRANCH,HAMPTON,VA 23681, USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 710 EP 718 DI 10.2514/3.26673 PG 9 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600019 ER PT J AU ALHORN, DC POLITES, ME AF ALHORN, DC POLITES, ME TI ROTATING UNBALANCED-MASS DEVICES FOR SCANNING - PROOF-OF-CONCEPT TEST-RESULTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PRECIS POINTING SYST BRANCH,HUNTSVILLE,AL 35812. RP ALHORN, DC (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,CONTROL ELECTR BRANCH,HUNTSVILLE,AL 35812, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JUL-AUG PY 1995 VL 32 IS 4 BP 732 EP 733 DI 10.2514/3.26676 PG 2 WC Engineering, Aerospace SC Engineering GA RP016 UT WOS:A1995RP01600022 ER PT J AU CHU, YC LAVRENTYEV, AI ROKHLIN, SI BAAKLINI, GY BHATT, RT AF CHU, YC LAVRENTYEV, AI ROKHLIN, SI BAAKLINI, GY BHATT, RT TI ULTRASONIC EVALUATION OF INITIATION AND DEVELOPMENT OF OXIDATION DAMAGE IN CERAMIC-MATRIX COMPOSITES SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article AB In this paper we report on the development of a method for ultrasonic nondestructive characterization of oxidation damage in ceramic-matrix composites, The method is based on ultrasonic measurement of elastic moduli of the composite, which are then used to determine the elastic moduli of the fiber-matrix interphase, Thus the interphasial damage may be estimated quantitatively, As a model system we used, to demonstrate applicability of the method, a unidirectional SiC-fiber-reinforced reaction-bonded silicon nitride matrix composite (SiC/RBSN), The composite samples mere oxidized in Bowing oxygen for 0.1, 1, 10, and 100 h at 600 degrees, 900 degrees, 1200 degrees, and 1400 degrees C, The ultrasonic phase velocity in the composite was measured at room temperature before and after oxidation; the data were then used to find the composite moduli, which quantify the induced damage, Significant changes in ultrasonic velocities and composite moduli were found as a result of oxidation, Fiber-matrix interphasial moduli were determined by multiphase micromechanical analysis, We found that oxidation of the carbon interphasial layer is the dominant mechanism in decreasing the elastic moduli of the composite, The critical exposure time for transition from the nondamaged to the damaged state at different oxidation temperatures has been determined. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CHU, YC (reprint author), OHIO STATE UNIV,NONDESTRUCT EVALUAT PROGRAM,COLUMBUS,OH 43210, USA. NR 22 TC 8 Z9 8 U1 0 U2 0 PU AMER CERAMIC SOC 735 CERAMIC PLACE PI WESTERVILLE PA PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUL PY 1995 VL 78 IS 7 BP 1809 EP 1817 DI 10.1111/j.1151-2916.1995.tb08893.x PG 9 WC Materials Science, Ceramics SC Materials Science GA RJ680 UT WOS:A1995RJ68000014 ER PT J AU Ghee, TA Elliott, JW AF Ghee, TA Elliott, JW TI The wake of a small-scale rotor in forward flight using flow visualization SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB An experimental investigation was conducted in the 14- by 22-Foot Subsonic tunnel at NASA Langley Research Center to quantify the rotor wake behind a scale model helicopter rotor in forward flight (mu = 0.15 and 0.23) at one thrust level (C-T = 0.0064). The rotor system used in the present test consisted of a four-bladed, fully articulated hub and utilized blades of rectangular planform with a NACA-0012 airfoil section. A laser light sheet, seeded with propylene glycol smoke, was used to visualize the flow in planes parallel and perpendicular to the freestream flow. Quantitative measurements of vortex location, vertical skew angle, and vortex particle void radius were obtained for vortices in the flow; convective velocities were obtained for blade tip vortices. Comparisons were made between the experimental results and the wake geometry generated by computational predictions. The results of these comparisons show that the interaction between wake vortex structures is an important consideration for correctly predicting the wake geometry. C1 NASA,LANGLEY RES CTR,DIRECTORATE ATCOM,USA AEROFLIGHTDYNAM,HAMPTON,VA 23665. RP Ghee, TA (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA, USA. NR 40 TC 8 Z9 9 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 1995 VL 40 IS 3 BP 52 EP 65 PG 14 WC Engineering, Aerospace SC Engineering GA TX639 UT WOS:A1995TX63900007 ER PT J AU Strawn, RC Biswas, R AF Strawn, RC Biswas, R TI Computation of helicopter rotor acoustics in forward flight SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article ID STOKES AB This paper presents a new method for computing acoustic signals from helicopter rotors in forward flight. The aerodynamic and acoustic solutions in the near field are computed with a finite-difference solver for the Euler equations. A nonrotating cylindrical Kirchhoff surface is then placed around the entire rotor system, This Kirchhoff surface moves subsonically with the rotor in forward flight. The finite-difference solution is interpolated onto this cylindrical surface at each time step and a Kirchhoff integration is used to carry the acoustic signal to the far field. Computed values for highspeed impulsive noise show excellent agreement with model-rotor and flight-test experimental data, Results from the new method offer high accuracy with reasonable computer resource requirements. C1 NASA,AMES RES CTR,RIACS,MOFFETT FIELD,CA 94035. RP Strawn, RC (reprint author), USA,AFDD,NASA,AMES RES CTR,MOFFETT FIELD,CA, USA. NR 16 TC 9 Z9 10 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 1995 VL 40 IS 3 BP 66 EP 72 PG 7 WC Engineering, Aerospace SC Engineering GA TX639 UT WOS:A1995TX63900008 ER PT J AU McCarthy, TR Chattopadhyay, A Talbot, PD Madden, JF AF McCarthy, TR Chattopadhyay, A Talbot, PD Madden, JF TI A performance based optimization of high speed prop-rotors SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB An optimization procedure is developed to investigate the effect of blade aerodynamic characteristics on cruise and hover performance of prop-rotor aircraft. The objective is to simultaneously maximize the high speed cruise propulsive efficiency and the hover figure of merit. Constraints are imposed on the hover and cruise thrust which are representative of the operating conditions of civil tiltrotor aircraft. Design variables include the blade chord, twist, thickness and zero lift angle of attack distributions. The aerodynamic analysis is performed using the classical blade element momentum approach, including a representation of the high lift potential of propeller/rotor blades in comparison to two dimensional airfoil properties. Optimum designs are presented for hover only, airplane mode only and for simultaneous hover/cruise modes. The results are compared with the XV-15 rotor blade performance at 300 knots. Optimum results for simultaneous hover/cruise modes are also presented for 400 knots operation. C1 NASA,AMES RES CTR,ROTORCRAFT TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP McCarthy, TR (reprint author), ARIZONA STATE UNIV,DEPT MECH & AEROSP ENGN,TEMPE,AZ 85287, USA. NR 22 TC 3 Z9 3 U1 0 U2 2 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 1995 VL 40 IS 3 BP 92 EP 100 PG 9 WC Engineering, Aerospace SC Engineering GA TX639 UT WOS:A1995TX63900011 ER PT J AU Hanson, JM Shrader, MW Cruzen, CA AF Hanson, JM Shrader, MW Cruzen, CA TI Ascent guidance comparisons SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB This paper contains results from ascent guidance studies conducted at the NASA Marshall Space Flight Center. The studies include investigation of different guidance schemes for a variety of potential launch vehicles. Criteria of a successful ascent guidance scheme are low operations cost, satisfaction of load indicator constraints, and maximization of performance. Results show that open-loop designs as a function of altitude or velocity are preferable to designs that are functions of time. Optimized open-loop trajectories can increase performance while maintaining load indicators within limits. Closed-loop atmospheric schemes that involve linear tangent steering or feedback of velocity terms for trajectory modification did not yield any improvement. Early release of vacuum closed-loop guidance, including use during solid rocket booster operation, yields some improvements. Evaluation of a closed-loop optimization scheme for flying through the atmosphere shows no advantages over open-loop optimization. Dispersion study results for several potential guidance schemes and launch vehicles are included in the paper and are not a discriminator between guidance schemes. The primary cost driver is mission operations philosophy, not choice of guidance scheme. More autonomous guidance schemes can help in movement towards a philosophy that would reduce operations costs. RP Hanson, JM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 15 TC 9 Z9 11 U1 2 U2 2 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JUL-SEP PY 1995 VL 43 IS 3 BP 307 EP 326 PG 20 WC Engineering, Aerospace SC Engineering GA TM799 UT WOS:A1995TM79900006 ER PT J AU WEI, MY AF WEI, MY TI A NEW FORMULATION OF THE EXCHANGE OF MASS AND TRACE CONSTITUENTS BETWEEN THE STRATOSPHERE AND TROPOSPHERE - REPLY SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Letter RP WEI, MY (reprint author), NASA,OFF MISS PLANER EARTH,DIV SCI,300 E ST SW,WASHINGTON,DC 20546, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1995 VL 52 IS 13 BP 2494 EP 2494 DI 10.1175/1520-0469(1995)052<2494:R>2.0.CO;2 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RG062 UT WOS:A1995RG06200013 ER PT J AU HARRELL, JA AF HARRELL, JA TI CONSTANT-BEAMWIDTH ONE-OCTAVE BANDWIDTH END-FIRE LINE ARRAY OF LOUDSPEAKERS SO JOURNAL OF THE AUDIO ENGINEERING SOCIETY LA English DT Article AB Broad-band acoustic signals, such as voice and music, intended for entertainment require uniform coverage over an audience such that the spectral distribution in the area remains constant. Thus the effective beamwidth of the acoustic source needs to be constant with frequency. The ideal solution to array-beamwidth control would be to create a coverage pattern that has one main lobe with small or no sidelobes, with the entire pattern remaining constant with frequency. Such a method for two-dimensional beamwidth control over an octave is presented. The methodology is most flexible and useful when utilizing digital signal processing, since the element responses could be derived with loudspeaker response corrections as part of the synthesis task. The relatively simple algebra of line array superposition yields constant beamwidths very close to theory (when the driver size is accounted for). Considering the strong match with predicted beam pattern, with 20-dB sidelobe suppression for weightings designed for such, this case is presented as a compelling validation of the basic technique. RP HARRELL, JA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 14 TC 3 Z9 3 U1 1 U2 1 PU AUDIO ENGINEERING SOC PI NEW YORK PA 60 E 42ND ST, NEW YORK, NY 10165-2520 SN 0004-7554 J9 J AUDIO ENG SOC JI J. Audio Eng. Soc. PD JUL-AUG PY 1995 VL 43 IS 7-8 BP 581 EP 591 PG 11 WC Acoustics; Engineering, Multidisciplinary SC Acoustics; Engineering GA RL992 UT WOS:A1995RL99200003 ER PT J AU KRASICH, M AF KRASICH, M TI IN PURSUIT OF EDUCATION SO JOURNAL OF THE INSTITUTE OF ENVIRONMENTAL SCIENCES LA English DT Editorial Material RP KRASICH, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 301-466,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCI PI MOUNT PROSPECT PA 940 E NORTHWEST HIGHWAY, MOUNT PROSPECT, IL 60056 SN 1052-2883 J9 J INST ENVIRON SCI JI J. Inst. Environ. Sci. PD JUL-AUG PY 1995 VL 38 IS 4 BP 14 EP 14 PG 1 WC Engineering, Environmental; Environmental Sciences; Instruments & Instrumentation SC Engineering; Environmental Sciences & Ecology; Instruments & Instrumentation GA RX832 UT WOS:A1995RX83200003 ER EF