FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Davies, JK Geballe, TR Hanner, MS Weaver, HA Crovisier, J Bockelee-Morvan, D AF Davies, JK Geballe, TR Hanner, MS Weaver, HA Crovisier, J Bockelee-Morvan, D TI Thermal infrared spectra of comet Hale-Bopp at heliocentric distances of 4 and 2.9 AU SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet; infrared; dust; silicates ID SPECTROPHOTOMETRY; C/1995-O1; AIRBORNE; P/HALLEY; GRAINS AB We present 10 and 20 mu m spectra of comet Hale-Bopp taken at UKIRT on 1996 June 20 and 1996 September 29. The 10 mu m spectra clearly show a strong silicate feature with peaks at 10.0 and 11.2 mu m. The 20 mu m spectrum on September 29 has strong excess flux relative to a blackbody and a peak near 19 mu m, in good agreement with the ISO SWS spectra obtained a week later. However, the 20 mu m spectrum on June 20 has significantly lower flux than would be expected based on a blackbody extrapolation from the flux at 12.5 mu m. C1 Joint Astron Ctr, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Observ Paris Meudon, F-92195 Meudon, France. RP Davies, JK (reprint author), Joint Astron Ctr, 660 N Aohoku Pl, Hilo, HI 96720 USA. RI Weaver, Harold/D-9188-2016 NR 14 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 293 EP 298 DI 10.1023/A:1006229906690 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400045 ER PT J AU Peschke, SB Grun, E Bohnhardt, H Campins, H Osip, DJ Hanner, MS Heinrichsen, I Knacke, RF Leinert, CH Lemke, D Stickel, M Lisse, CM Sykes, M Zarnecki, J AF Peschke, SB Grun, E Bohnhardt, H Campins, H Osip, DJ Hanner, MS Heinrichsen, I Knacke, RF Leinert, CH Lemke, D Stickel, M Lisse, CM Sykes, M Zarnecki, J TI Isophot observations of comet Hale-Bopp - First results SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet Hale-Bopp; ISOPHOT; spectral energy distribution; dust temperatures ID C/1995-O1 AB Comet Hale-Bopp has been observed five times with ISOPHOT, the photometer on board the Infrared Space Observatory (ISO), four times before its perihelion passage at heliocentric distances of 4.92, 4.58, 2.93 and 2.81 AU, and at 3.91 AU postperihelion. Each time, multi-filter photometry covering the range between 3.6-175 mu m with eight to ten filters was performed to sample the spectral energy distribution of the comet. These measurements were used to determine dust temperatures for the cometary coma. The evolution of the strength of the silicate feature can be followed in the data as well as the flux deficit at longer wavelengths. C1 Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. European So Observ, Santiago 19, Chile. Univ Florida, Gainesville, FL USA. Jet Prop Labs, Pasadena, CA USA. ESA, Div Astrophys, ISO Sci Operat Ctr, Vilspa, Spain. Penn State Univ, Erie, PA 16563 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Maryland, College Pk, MD 20742 USA. Univ Arizona, Tucson, AZ USA. Univ Kent, Canterbury, Kent, England. RP Max Planck Inst Kernphys, Saupfercheckweg 1, D-69117 Heidelberg, Germany. EM peschke@galileo.mpi-hd.mpg.de RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 8 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 EI 1573-0794 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 299 EP 304 DI 10.1023/A:1006281923528 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400046 ER PT J AU Sekanina, Z Boehnhardt, H AF Sekanina, Z Boehnhardt, H TI Dust morphology of comet Hale-Bopp (C/1995 O1). II. Introduction of a working model SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet Hale-Bopp; nucleus; active area; dust morphology; computer modelling ID 1995-O1 AB A Monte Carlo image simulation code for dust features in comets is applied to comet Hale-Bopp in order to model the object's persistent porcupine-like appearance on high-resolution images taken between May 11 and Nov. 2, 1996. A self-consistent fan model is proposed, with six isolated sources of dust emission assumed at various locations on the surface of the rotating nucleus and with the spin axis undergoing a complex motion in an inertial coordinate system. In the framework of this model, jet pairs represent boundaries of fan-shaped formations described by dust ejected from isolated sources during periods of time when the Sun is above the local horizon. The spin axis is found to have traveled through a field of 10 degrees by 20 degrees during the examined period of nearly six months. Still more successful is a fan model with large diurnal dust-emission fluctuations, which is consistent with an inertially fixed position of the spin axis and requires only three discrete sources. In this scenario, the dust-emission profile is dominated by several brief flare-ups, or "puffs", in the production of dust from one of the sources. The results are insensitive to the spin rate, but the observed dust coma appearance is more typical of a rapidly rotating comet. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European So Observ, Santiago 19, Chile. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 8 Z9 8 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 313 EP 319 DI 10.1023/A:1006286024437 PG 7 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400048 ER PT J AU Pittichova, J Sekanina, Z Birkle, K Boehnhardt, H Engels, D Keller, P AF Pittichova, J Sekanina, Z Birkle, K Boehnhardt, H Engels, D Keller, P TI An early investigation of the striated tail of comet Hale-Bopp (C/1995 O1) SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet Hale-Bopp; dust tail; striae; particle fragmentation; particle lifetime; emission source ID DUST AB The Sekanina-Farrell particle fragmentation model for the striated tails of dust comets is successfully applied to two images of comet Hale-Bopp to study the motions of 12 striae in a time span of March 12-15, 1997. There is evidence for recurring outbursts with a periodicity of 11(h) 21(m), consistent with results based on analysis of dust jets. The ejecta in all the striae appear to have been released from one source on the nucleus between the end of January and the second half of February 1997, some 60 to 40 days before perihelion. The parent particles were subjected to a radiation pressure acceleration of beta(p) similar or equal to 0.55 and their fragmentation lifetimes in 11 of the 12 striae were practically constant and equal to 13-15 days, when normalized to 1 AU from the Sun. Brief analysis of Watanabe et al.'s measurements of striae on their images from March 5-9, 1997 shows even shorter fragmentation lifetimes for the parent particles, mostly about 7-11 days at 1 AU. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Slovak Acad Sci, Astron Inst, Bratislava, Slovakia. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Ctr Astron Hispano Aleman, Almeria, Spain. European So Observ, Santiago 19, Chile. Hamburger Sternwarte, Hamburg, Germany. RP CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 EI 1573-0794 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 329 EP 338 DI 10.1023/A:1006242209416 PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400050 ER PT J AU Sekanina, Z Pittichova, J AF Sekanina, Z Pittichova, J TI Distribution law for particle fragmentation times in a theory for striated tails of dust comets: Application to comet Hale-Bopp (C/1995 O1) SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet Hale-Bopp; dust tail; striae; particle fragmentation; particle lifetime; distribution of fragmentation times AB Sekanina and Farrell's model for the striated dust tails of comets describes the formation of striae as a two-step fragmentation process that is characterized by an ejection time t(e) of parent particles, by their radiation pressure acceleration beta(p), and by their fragmentation time t(f). Of these three, t(f) is the weakest parameter in that a range of t(f) offers a set of nearly equivalent solutions. In this context, we comment on Nishioka et al.'s finite-lifetime model, which is a modification of the fragmentation model. We propose a truncated Gaussian function as a first-approximation distribution law for particle fragmentation times. We apply this generalized model to a stria in comet Hale-Bopp detected on March 5-15, 1997 and analyzed by Pittichova et al. in a recent paper. We find that in order to fit the stria's estimated width of similar to 150 000 km, the fragmentation times cannot be distributed over a period of more than approximately 2 to 3 days. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Slovak Acad Sci, Astron Inst, Bratislava, Slovakia. European So Observ, Munich, Germany. RP CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 EI 1573-0794 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 339 EP 346 DI 10.1023/A:1006294226254 PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400051 ER PT B AU Chu, WP McCormick, MP Zawodny, JM Mauldin, LE AF Chu, WP McCormick, MP Zawodny, JM Mauldin, LE BE Barnes, WL TI Stratospheric aerosol and gas experiment III SO EARTH OBSERVING SYSTEMS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Earth Observing Systems II Conference CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE remote sensing; space-borne instrument; aerosols; ozone; environmental monitoring; climate monitoring AB SAGE III is part of the Mission to Planet Earth's (MTPE) Earth Observatory System (EOS) with a first launch in the summer of 1998. SAGE III will provide long term monitoring of atmospheric species such as ozone and aerosols which play an important role in global environmental and climatic changes. This paper will briefly describe the goal of the SAGE LII experiment, the instrument design, and the development of the processing algorithm for routine data processing to produce scientifically important data products for the science community. RP Chu, WP (reprint author), NASA,LANGLEY RES CTR,MS 475,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2539-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3117 BP 11 EP 18 DI 10.1117/12.283815 PG 8 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ67N UT WOS:A1997BJ67N00002 ER PT B AU Atlas, R AF Atlas, R BE Barnes, WL TI Preliminary evaluation of NASA scatterometer data and its application to ocean surface analysis and numerical weather prediction SO EARTH OBSERVING SYSTEMS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Earth Observing Systems II Conference CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers RP Atlas, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DATA ASSIMILAT OFF,CODE 910-4,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2539-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3117 BP 90 EP 97 DI 10.1117/12.278914 PG 8 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ67N UT WOS:A1997BJ67N00010 ER PT B AU Woodhouse, RM Bruegge, CJ Gaitley, BJ Saghri, G Chrien, NL AF Woodhouse, RM Bruegge, CJ Gaitley, BJ Saghri, G Chrien, NL BE Barnes, WL TI Multi-angle Imaging SpectroRadiometer (MISR) ancillary radiometric product SO EARTH OBSERVING SYSTEMS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Earth Observing Systems II Conference CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE ARP; DAAC; EOS; MISR; radiometric calibration; SCF; SDP; spectral calibration AB The in-flight calibration program for the EOS-AM1 Multi-angle Imaging SpectroRadiometer (MISR) includes on-orbit calibration, characterization of instrument properties and a calibration integrity process. One of the primary activities of the In-flight Radiometric Calibration and Characterization (IFRCC) group responsible for the MISR calibration program at the Science Computing Facility (SCF) is to produce a data file called the Ancillary Radiometric Product (ARP). Radiance scaling and conditioning processing at the Distributed Active Archive Center (DAAC), as well as other science data product generation, proceed using ARP parameters. The parameters that make up the ARP include pre-flight data which give an account of the instrument radiometric response, along with other instrument descriptors. Radiometric response will be maintained and updated throughout the mission. RP Woodhouse, RM (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2539-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3117 BP 158 EP 169 DI 10.1117/12.283805 PG 12 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ67N UT WOS:A1997BJ67N00018 ER PT B AU Bruegge, CJ Diner, DJ AF Bruegge, CJ Diner, DJ BE Barnes, WL TI Instrument verification tests on the Multi-angle Imaging SpectroRadiometer (MISR) SO EARTH OBSERVING SYSTEMS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Earth Observing Systems II Conference CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE MISR; verification testing; geometric calibration AB The Multi-angle Imaging SpectroRadiometer (MISR) cameras completed detailed calibration and characterization testing a year ago, as reported in earlier literature. Since that time the cameras have been assembled onto a common flight optical bench, along with photodiode detector standards and diffuse calibration targets. The orderly multiplexing of high-rate data streams from nine camera, twenty-four calibration photodiode channels, and engineering measurements of temperatures and voltages into packets has been verified. Camera fields-of-view clearances have been established, and a verification of camera and photodiode relative response established. These verification tests of the instrument have been followed by shipment of the instrument to the spacecraft integrator facility, where testing continues. Even for the simplest of experiments, the insight learned into the functionality of the instrument has been invaluable. This paper reviews a sampling of these tests and lessons learned, from the simplest verification experiments, to the complex camera boresight determinations. RP Bruegge, CJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2539-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3117 BP 170 EP 175 DI 10.1117/12.283806 PG 6 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ67N UT WOS:A1997BJ67N00019 ER PT B AU Lee, RB Smith, GL Barkstrom, BR Priestley, KJ Thomas, S Paden, J Pandey, DK Thornhill, KL Bolden, WC Wilson, RS AF Lee, RB Smith, GL Barkstrom, BR Priestley, KJ Thomas, S Paden, J Pandey, DK Thornhill, KL Bolden, WC Wilson, RS BE Barnes, WL TI Ground calibrations of the clouds and the earth's radiant energy system (CERES) tropical rainfall measuring mission spacecraft thermistor bolometers SO EARTH OBSERVING SYSTEMS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Earth Observing Systems II Conference CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE radiometry; calibration; climate; longwave; shortwave AB The Clouds and the Earth's Radiant Energy System (CERES) spacecraft scanning thermistor bolometers will measure earth-reflected solar and earth-emitted longwave radiances, at tile top-of-the-atmosphere. The measurements are performed in the broadband shortwave (0.3 - 5.0 mu m) and longwave (5.0 - >100 mu m) spectral regions as well as in the 8 - 12 mu m water vapor window over geographical footprints as smell as 10 kilometers at the nadir. The CERES measurements are designed to improve our knowledge of the earth's natural climate processes, in particular those related to clouds, and man's impact upon climate as indicated by atmospheric temperature. November 1997, the first set of CERES bolometers is scheduled for launch on the Tropical Rainfall Measuring Mission (TRMM) Spacecraft. The CERES bolometers were calibrated radiometrically in a vacuum ground facility using absolute reference sources, tied to the International Temperature Scale of 1990. Accurate bolometer calibrations are dependent upon the derivations of the radiances from the spectral properties [reflectance, transmittance, emittance, etc.] of both the sources and bolometers. In this paper, the overall calibration approaches are discussed for the longwave and shortwave calibrations. The spectral responses for the TRMM bolometer units are presented and applied to the bolometer ground calibrations in order to determine pre-launch calibration gains. RP Lee, RB (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MS 420,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2539-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3117 BP 281 EP 293 PG 13 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ67N UT WOS:A1997BJ67N00031 ER PT S AU Smith, JA Pedelty, JA Ballard, JR Schmugge, TJ AF Smith, JA Pedelty, JA Ballard, JR Schmugge, TJ BE Cecchi, G Engman, ET Zilioli, E TI Three-dimensional modeling of agricultural canopies for thermal IR excitance studies SO EARTH SURFACE REMOTE SENSING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Earth Surface Remote Sensing CY SEP 22-25, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE thermal infrared; canopy model; brightness temperature; surface energy balance AB We present a simple, three-dimensional vegetation canopy thermal infrared exitance model for agricultural scenes. Computer graphics and ray-tracing techniques are used to estimate three-dimensional canopy view factors and scene shadows. The view factors are used to weight the individual contributions of soil and vegetation emission computed by steady-state energy budget formulations. We compare the three-dimensional model results to a one-dimensional formulation for an agricultural test site from the Hydrologic Atmospheric Pilot Experiment and Modelisation du Bilan Hydrique. The root mean square error in daylight brightness temperature for the one dimensional model was 2.5 deg C and 2.0 deg C for the three dimensional model. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2654-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3222 BP 50 EP 57 PG 8 WC Agronomy; Forestry; Geosciences, Multidisciplinary; Remote Sensing; Optics; Water Resources SC Agriculture; Forestry; Geology; Remote Sensing; Optics; Water Resources GA BK34B UT WOS:000071842800005 ER PT S AU Engman, ET AF Engman, ET BE Cecchi, G Engman, ET Zilioli, E TI Potential for remotely sensed soil moisture data in hydrologic modeling SO EARTH SURFACE REMOTE SENSING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Earth Surface Remote Sensing CY SEP 22-25, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev AB Many hydrologic processes display a unique signature that is detectable with microwave remote sensing. These signatures are in the form of the spatial and temporal distributions of surface soil moisture and portray the spatial heterogeneity of hydrologic processes and properties that one encounters in drainage basins. The hydrologic processes that may be detected include ground water recharge and discharge zones, storm runoff contributing areas, regions of potential and less than potential ET, and information about the hydrologic properties of soils and heterogeneity of hydrologic parameters. Microwave remote sensing has the potential to detect these signatures within a basin in the form of volumetric soil moisture measurements in the top few cm.. These signatures should provide information on how and where to apply soil physical parameters in distributed and lumped parameter models and how to subdivide drainage basins into hydrologically similar sub-basins. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Hydrospher Proc Lab, Greenbelt, MD 20771 USA. RP Engman, ET (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Hydrospher Proc Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2654-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3222 BP 161 EP 170 PG 10 WC Agronomy; Forestry; Geosciences, Multidisciplinary; Remote Sensing; Optics; Water Resources SC Agriculture; Forestry; Geology; Remote Sensing; Optics; Water Resources GA BK34B UT WOS:000071842800017 ER PT S AU Krishnan, GS AF Krishnan, GS BE KaldeichSchurmann, B TI Management of a coordinated Parts Program SO EECC'97 - PROCEEDINGS OF THE THIRD ESA ELECTRONIC COMPONENTS CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 3rd ESA Electronic Components Conference (EECC 97) CY APR 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP European Space Agcy, ESTEC HO ESTEC AB NASA is involved in projects conducting experiments related to earth, solar, and galactic studies in space via various manned and unmanned missions. Instruments are fabricated by experiments, using electrical, electronics, and electro-mechanical (EEE) parts, to conduct such experiments. Reliable operation of the Instrument is the key to the success of the mission and as such management of the parts program is vital. This paper describes briefly how a Parts Program is managed in general and goes on to describe in detail how a specific coordinated Parts Program was managed utilizing the services of the Support Contractor. This paper also discusses the organizational structure faced by the Parts Manager and the advantages and disadvantages of managing a coordinated Parts Program. It concludes with the future research that will be conducted in the area of management of a Parts Program, the setting up of Decision Support Model that will aid the Parts Manager in the decision making and the controlling processes. RP Krishnan, GS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,8714 GILBERT PL,7 TAKOMA PK,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-263-X J9 ESA SP PUBL PY 1997 VL 395 BP 107 EP 111 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BJ69Z UT WOS:A1997BJ69Z00015 ER PT S AU Krishnan, GS AF Krishnan, GS BE KaldeichSchurmann, B TI Application of artificial intelligence (AI) concepts to the development of space flight parts approval model SO EECC'97 - PROCEEDINGS OF THE THIRD ESA ELECTRONIC COMPONENTS CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 3rd ESA Electronic Components Conference (EECC 97) CY APR 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP European Space Agcy, ESTEC HO ESTEC AB The National Aeronautics & Space Administration (NASA), and the European Space Agency (ESA) missions involves the performance of scientific experiments in Space. To perform these experiments, instruments are designed, developed, built, and launched. The Instruments are fabricated using many electronic parts. For Instruments to perform reliably for the specified duration of the mission, the selection of commercial parts must be monitored and strictly controlled. NASA's process to achieve this goal is by the review and approval of commercial parts used to build the Instrument. ESA also follows a similar process although some requirements are different. The present system to select and approve parts for space applications is very inefficient, manual, inconsistent, slow and tedious, and very costly. This paper presents a cost-effective, accurate, and consistent model which uses the artificial intelligence techniques in the selection and approval of parts. The knowledge which is acquired from the specialists for different part types are then represented in a knowledge base in the form of rules and objects. The parts information is stored separately in a database and is isolated from the knowledge base for ease of maintenance. Validation, verification, and performance issues as well as other implementation details are highlighted. RP Krishnan, GS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-263-X J9 ESA SP PUBL PY 1997 VL 395 BP 147 EP 155 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BJ69Z UT WOS:A1997BJ69Z00021 ER PT S AU Shaw, JJ Virmani, N AF Shaw, JJ Virmani, N BE KaldeichSchurmann, B TI Preliminary reliability evaluation of Flip Chip on Flex interconnect technology SO EECC'97 - PROCEEDINGS OF THE THIRD ESA ELECTRONIC COMPONENTS CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 3rd ESA Electronic Components Conference (EECC 97) CY APR 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP European Space Agcy, ESTEC HO ESTEC RP Shaw, JJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ELECT PACKAGING & PROC BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-263-X J9 ESA SP PUBL PY 1997 VL 395 BP 205 EP 212 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BJ69Z UT WOS:A1997BJ69Z00030 ER PT S AU Barnes, C Johnston, A Lee, C Swift, G Rax, B AF Barnes, C Johnston, A Lee, C Swift, G Rax, B BE KaldeichSchurmann, B TI Recent radiation effects activities at JPL: Coping with cots SO EECC'97 - PROCEEDINGS OF THE THIRD ESA ELECTRONIC COMPONENTS CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 3rd ESA Electronic Components Conference (EECC 97) CY APR 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP European Space Agcy, ESTEC HO ESTEC AB In this paper we discuss radiation effects issues that have become important for NASA programs in the last few years. Particularly critical is the increasing usage of commercial off-the-shelf (COTS) devices and circuits in interplanetary missions that experience significant exposure to radiation. Demands for increased performance levels in spacecraft systems will drive the insertion of the latest electronic and photonic devices. Advances in electronics to achieve high performance will result in scaling (miniaturization) of devices, which, in turn, will lead to increased radiation vulnerability in many cases. These issues are discussed within the context of recent technical examples of challenging radiation effects problems. RP Barnes, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-263-X J9 ESA SP PUBL PY 1997 VL 395 BP 227 EP 244 PG 18 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BJ69Z UT WOS:A1997BJ69Z00032 ER PT B AU Buehler, MG Ryan, MA AF Buehler, MG Ryan, MA BE Fallahi, M Howden, E TI Temperature and humidity dependence of a polymer-based gas sensor SO ELECTRO-OPTICAL TECHNOLOGY FOR REMOTE CHEMICAL DETECTION AND IDENTIFICATION II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Electro-Optical Technology for Remote Chemical Detection and Identification II CY APR 21, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE gas sensor; polymers; temperature; humidity; test circuit; test chip; co-fired ceramic AB This paper quantifies the temperature and humidity dependence of a polymer-based gas sensor. The measurement and analysis of three polymers indicates that resistance changes in the polymer films, due to temperature and humidity, can be positive or negative. The temperature sensitivity ranged from +1600 to -320 ppm/degrees C and the relative humidity sensitivity ranged from +1100 to -260 ppm/%. These results were obtained from three-day experiments in an air ambient where the gas sensors were kept in stagnant air to allow for equilibration of the gas sensors and instruments used to measure the temperature and humidity. In spite of significant variations in temperature and humidity, the detection of 50 ppm resistance changes is possible. RP Buehler, MG (reprint author), CALTECH,JET PROP LAB,MICRODEVICES LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2497-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3082 BP 40 EP 48 DI 10.1117/12.280933 PG 9 WC Chemistry, Analytical; Engineering, Electrical & Electronic; Optics SC Chemistry; Engineering; Optics GA BJ34Z UT WOS:A1997BJ34Z00005 ER PT B AU Chettri, S Netanyahu, N AF Chettri, S Netanyahu, N BE Schaefer, D Williams, EF TI Spectral unmixing of remotely sensed imagery using Maximum Entropy SO EMERGING APPLICATIONS OF COMPUTER VISION - 25TH AIPR WORKSHOP SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 25th AIPR Workshop on Emerging Applications of Computer Vision CY OCT 16-18, 1996 CL WASHINGTON, DC SP Soc Photo Opt Instrumentat Engineers, Appl Imagery Pattern Recognit Execut Comm DE spectral unmixing; maximum entropy; remote sensing; information theory; statistical thermodynamics AB This paper addresses the importance of a maximum entropy formulation for the extraction of content from a single picture element in a remotely sensed image. Most conventional classifiers assume a winner take all procedure in assigning classes to a pixel whereas in general it is the case that there exists more than one class within the picture element. There have been attempts to perform spectral unmixing using variants of least-squares techniques, but these suffer from conceptual and numerical problems which include the possibility that negative fractions of ground cover classes may be returned by the procedure. In contrast, a maximum entropy (MAXENT) based approach for sub-pixel content extraction possesses the useful information theoretic property of not assuming more information than is given, while automatically guaranteeing positive fractions. In this paper we apply MAXENT to obtain the fractions of ground cover classes present in a pixel and show its clear numerical superiority over conventional methods. The optimality of this method stems from the combinatorial properties of the information theoretic entropy. RP Chettri, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GST,CODE 9350,GREENBELT,MD 20771, USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2366-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 2962 BP 55 EP 62 DI 10.1117/12.267839 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BH32N UT WOS:A1997BH32N00006 ER PT B AU Raghavan, S Cromp, R Srinivasan, S Poovendran, R Campbell, WJ Kanal, L AF Raghavan, S Cromp, R Srinivasan, S Poovendran, R Campbell, WJ Kanal, L BE Schaefer, D Williams, EF TI Extracting an image similarity index using meta-data content for image mining applications SO EMERGING APPLICATIONS OF COMPUTER VISION - 25TH AIPR WORKSHOP SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 25th AIPR Workshop on Emerging Applications of Computer Vision CY OCT 16-18, 1996 CL WASHINGTON, DC SP Soc Photo Opt Instrumentat Engineers, Appl Imagery Pattern Recognit Execut Comm AB The motivation behind this research has been to identify, and where possible, minimize or eliminate potential problem areas facing NASA in its mission of gathering and analyzing remotely-sensed imagery in both Earth and space disciplines. Managing and extracting useful information from the massive image databases resulting from such missions is a challenging task for NASA. The key to real-time archival and retrieval of this massive image data lies in the notion of content based image data management. Two major steps are involved in this process. The first one is to automatically extract image content or meta-data from satellite imagery. The second one is to organize this database to permit users from numerous disciplines and communities to access data relevant to their needs. Accordingly, each data set is indexed in multiple ways, enabling users to retrieve images by specifying constraints over a combination of attributes. One such method provides users the ability to search the data holdings using a metric of similarity in content so that neighboring images in the database have a high probability of hit when queried for a specific type of meta-data content. An important area of research is therefore to compute and evaluate similarity measures for images. In this paper, we present a backpropagation neural network based technique to classify a multispectral satellite image and extract a similarity measure using the meta-data classification content. RP Raghavan, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 935,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2366-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 2962 BP 78 EP 91 DI 10.1117/12.267841 PG 14 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BH32N UT WOS:A1997BH32N00008 ER PT B AU Reed, K AF Reed, K BE Schaefer, D Williams, EF TI Milestones on the road to independence for the blind. SO EMERGING APPLICATIONS OF COMPUTER VISION - 25TH AIPR WORKSHOP SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 25th AIPR Workshop on Emerging Applications of Computer Vision CY OCT 16-18, 1996 CL WASHINGTON, DC SP Soc Photo Opt Instrumentat Engineers, Appl Imagery Pattern Recognit Execut Comm AB Ken will talk about his experiences as an end user of technology. Even moderate technological progress in the field of pattern recognition and artificial intelligence can be, often suprisingly, of great help to the Blind. An example is the providing of portable bar code scanners so that a blind person knows what he is buying and what color it is. In this age of microprocessors controlling everything, how can a blind person find out what his VCR is doing? Is there some technique that will allow a blind musician to convert print music into midi files to drive a synthesizer? Can computer vision help the blind cross a road including predictions of where oncoming traffic will be located? Can computer vision technology provide spoken description of scenes so a blind person can figure out where doors and entrances are located, and what the signage on the building says? He asks ''can computer vision help me flip a pancake?'' His challenge to those in the computer vision field is ''where can we go from here?'' RP Reed, K (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SOLID STATE DEVICE DEV BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2366-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 2962 BP 94 EP 96 DI 10.1117/12.267812 PG 3 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BH32N UT WOS:A1997BH32N00009 ER PT J AU Brooke, TY AF Brooke, TY TI Comets and interstellar ices: a cosmic connection SO ENDEAVOUR LA English DT Article ID CHEMICAL-MODELS; HYAKUTAKE; SPECTRUM; WATER AB The most abundant volatile molecules released from comets are also seen in the ice phase on grains in interstellar molecular clouds. Recent detections of new trace molecules in comet Hyakutake provide further evidence for a link between the two. RP Brooke, TY (reprint author), NASA,JET PROP LAB,PASADENA,CA 91109, USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0160-9327 J9 ENDEAVOUR JI Endeavour PY 1997 VL 21 IS 3 BP 101 EP 104 DI 10.1016/S0160-9327(97)80217-7 PG 4 WC History & Philosophy Of Science; Multidisciplinary Sciences SC History & Philosophy of Science; Science & Technology - Other Topics GA YA204 UT WOS:A1997YA20400003 ER PT J AU Bikle, DD Halloran, BP MoreyHolton, E AF Bikle, DD Halloran, BP MoreyHolton, E TI Space flight and the skeleton: Lessons for the earthbound SO ENDOCRINOLOGIST LA English DT Review ID GROWTH-FACTOR-I; FETAL-RAT CALVARIAE; INDUCED BONE LOSS; MESSENGER-RIBONUCLEIC-ACID; RESTORES CANCELLOUS BONE; OSTEOBLAST-LIKE CELLS; IGF-BINDING-PROTEIN; GROWING RATS; BED-REST; SIMULATED WEIGHTLESSNESS AB Loss of bone during extended space flight has long been a concern that could limit the ability of humans to explore the universe. Surprisingly, the available data do not support the concept that weightlessness leads inexorably to a depleted skeleton unable to withstand the stress of a return to a 1-g environment. Nevertheless, some bone loss does occur, especially in those bones most stressed by gravity prior to flight, which provides confirmation of the proposal formulated over a century ago by Julius Wolff that mechanical stress determines the form and function of bone. Although the phenomenon of bone loss with skeletal unloading, whether by space night or immobilization or just taking a load off your feet (literally) is well established, the mechanisms by which bone senses load and adjusts to it are not so clear. What actually is the stimulus, and what are the sensors? What are the target cells' How do the sensors communicate the message into the cells, and by what pathways do the cells respond? What is the role of endocrine factors vs. paracrine or autocrine factors in mediating or modulating the response? None of these questions has been answered with certainty, but, as will become apparent in this review, we have some some clues directing us to the answers. Although the focus of this review concerns space flight, it seems highly likely that the mechanisms mediating the transmission of mechanical load to changes in bone formation and resorption apply equally well to all forms of disuse osteoporosis and are likely to be the same mechanisms affected by other etiologies of osteoporosis. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Bikle, DD (reprint author), UNIV CALIF SAN FRANCISCO, VET AFFAIRS MED CTR, ENDOCRINE UNIT 111N, 4150 CLEMENT ST, SAN FRANCISCO, CA 94121 USA. NR 149 TC 34 Z9 34 U1 0 U2 3 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 1051-2144 J9 ENDOCRINOLOGIST JI Endocrinologist PD JAN-FEB PY 1997 VL 7 IS 1 BP 10 EP 22 PG 13 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA WK649 UT WOS:A1997WK64900003 PM 11540416 ER PT J AU Perry, CA Gurdal, Z Starnes, JH AF Perry, CA Gurdal, Z Starnes, JH TI Minimum-weight design of compressively loaded stiffened panels for postbuckling response SO ENGINEERING OPTIMIZATION LA English DT Article DE buckling; composite design; imperfection sensitivity; postbuckling; stiffened panels ID OPTIMIZATION; COMPOSITE AB A computationally efficient procedure, NLPANOPT, is developed for the optimal design of thin-walled stiffened composite panels loaded in uniaxial compression based on a geometrically nonlinear analysis. An approximate, semi-analytical nonlinear analysis code NLPAN, which requires buckling eigenfunction information from the buckling analysis code VIPASA, has been linked with the optimization code ADS. To demonstrate the capabilities, a blade stiffened panel is designed using NLPANOPT. For the same configuration, optimal designs based on a linear analysis are obtained using the design code PASCO. Comparisons of panel weight and imperfection sensitivity between the linear designs and nonlinear designs are made. In general, the designs that are obtained based on the nonlinear analysis are lighter and less imperfection sensitive. C1 NASA,LANGLEY RES CTR,STRUCT MECH BRANCH,HAMPTON,VA 23681. RP Perry, CA (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061, USA. NR 14 TC 13 Z9 13 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0305-215X J9 ENG OPTIMIZ JI Eng. Optimiz. PY 1997 VL 28 IS 3 BP 175 EP 197 DI 10.1080/03052159708941131 PG 23 WC Engineering, Multidisciplinary; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA XW019 UT WOS:A1997XW01900002 ER PT B AU McCandless, JW Kaiser, MK AF McCandless, JW Kaiser, MK BE Verly, JG TI Obstacle detection in air-to-air images SO ENHANCED AND SYNTHETIC VISION 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Enhanced and Synthetic Vision 1997 CY APR 21-22, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE image; obstacle detection; optical flow; gradient; expansion; translation; divergence; collision AB One means of locating and classifying obstacles in video images is through the analysis of optical flow, defined as the motion on the image surface that results from camera and/or object motion. We present a computer vision algorithm that analyzes two classes of optical flow to determine the direction of a moving object captured in image sequences. First, the optical flow is computed with the Lucas-Kanade gradient-based technique. Then, the optical flow at each point in the image is decomposed into a translation component (by examining the consistency of the flow in the surrounding region) and an expansion component (by computing the divergence). Translation optical flow can be caused by motion perpendicular to the line of sight, whereas expansion optical flow can be caused by motion along the line of sight. By analyzing both types of optical flow, our computer vision algorithm successfully classifies scenarios into four types: 1) a collision condition; 2) a crossing condition, in which the target crosses in front of the camera; 3) a passing condition, in which the target passes to the side of the camera; and 4) a safe condition, in which the target travels away from the camera. RP McCandless, JW (reprint author), NASA,AMES RES CTR,FLIGHT MANAGEMENT & HUMAN FACTORS DIV,MS 262-2,MOFFETT FIELD,CA 94035, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2503-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3088 BP 40 EP 49 DI 10.1117/12.277243 PG 10 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Electrical & Electronic; Optics SC Engineering; Computer Science; Optics GA BJ16R UT WOS:A1997BJ16R00005 ER PT B AU Parsons, A Palmer, DM Kurczynski, P Barbier, L Barthelmy, S Bartlett, L Gehrels, N Krizmanic, J Stahle, CM Tueller, J Teegarden, B AF Parsons, A Palmer, DM Kurczynski, P Barbier, L Barthelmy, S Bartlett, L Gehrels, N Krizmanic, J Stahle, CM Tueller, J Teegarden, B BE Siegmund, OHW Gummin, MA TI Position resolution performance of prototype segmented CdZnTe arrays SO EUX, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy VIII CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE CdZnTe; BASIS; CZT; solid-state radiation detectors; gamma-ray bursts AB The Burst and All Sky Imaging Survey (BASIS) is a proposed mission to provide +/-3 are-second locations of an estimated 90 Gamma-Ray Bursts (GRBs) per year. The BASIS coded aperture imaging system requires a segmented detector plane able to detect the position of photon absorption to less than 100 microns. To develop prototype detector arrays with such fine position resolution we have fabricated many 15 mm x 15 mm x 2 mm 100 micron pitch CdZnTe strip detectors. A 2 x 2 prototype 100 micron CdZnTe strip detector array has been fabricated and has been used to test the capabilities of the BASIS imaging system. Preliminary shadowgrams of a 1 mm wide gap between two tungsten straight edges indicate that our position resolution is on the order of 69 mu m. Both the array and imaging tests will be described. A 6 x 6 element CdZnTe detector array is also being fabricated at GSFC. The assembly of this flight prototype array will be discussed as well as applications for BASIS. RP Parsons, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 661,GREENBELT,MD 20771, USA. RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012; Parsons, Ann/I-6604-2012 NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2536-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3114 BP 341 EP 348 DI 10.1117/12.283778 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Engineering; Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BJ87K UT WOS:A1997BJ87K00028 ER PT B AU Zhang, W Petre, R Peele, AN Jahoda, K Marshall, FE Soong, Y White, NE AF Zhang, W Petre, R Peele, AN Jahoda, K Marshall, FE Soong, Y White, NE BE Siegmund, OHW Gummin, MA TI A broad band and large area X-ray omni sky monitor (BLOSM) SO EUX, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy VIII CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE instrumentation; x-ray optics, all sky monitor AB We present a conceptual design for a new X-ray all sky monitor (ASM). Compared with previous ASMs, its salient features are: (1) it has a focusing capability that increases the signal to background ratio by a factor of 3; (2) it has a broad-band width: 200 eV to 15 keV; (3) it has a large X-ray collection area: similar to 10(2) cm(2); (4) it has a duty cycle of nearly 100%, and (5) it can measure the position of a new source with an accuracy of a few minutes of are. These features combined open up an opportunity for discovering new phenomena as well as monitoring existing phenomena with unprecedented coverage and sensitivity. RP Zhang, W (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012; Jahoda, Keith/D-5616-2012 OI White, Nicholas/0000-0003-3853-3462; NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2536-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3114 BP 466 EP 480 DI 10.1117/12.283787 PG 15 WC Engineering, Aerospace; Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Engineering; Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BJ87K UT WOS:A1997BJ87K00040 ER PT B AU Tveekrem, JL KeskiKuha, RAM Webb, AT AF Tveekrem, JL KeskiKuha, RAM Webb, AT BE Siegmund, OHW Gummin, MA TI Gas permeability through thin-foil X-ray filters SO EUX, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy VIII CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE X-ray; filter; permeation; leak rate; outgassing; contamination AB We have measured the permeation rates of helium and water through thin-foil UV-blocking filters used in the ASTRO-E/X-Ray Spectrometer (XRS) instrument. In the XRS program, there is a concern that outgassed contaminants such as water could permeate through the outermost filter which will be at room temperature and freeze on the inner filters which will be at cryogenic temperatures. The filters tested consisted of similar to 1000 Angstrom Al on similar to 1000 Angstrom of either Lexan or polyimide. Measurements were made using a vacuum apparatus consisting essentially of two small chambers separated by the filter under test. A helium leak detector was used to measure helium permeation rates, and a residual gas analyzer (RGA) was used to detect water. Results discussed include permeation rate as a function of pressure difference across a filter, the ratio of helium permeation rate over water permeation rate, and the effect of the aluminum layer thickness on permeation. RP Tveekrem, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2536-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3114 BP 506 EP 513 DI 10.1117/12.278900 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Engineering; Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BJ87K UT WOS:A1997BJ87K00044 ER PT B AU Larruquert, JI KeskiKuha, RAM AF Larruquert, JI KeskiKuha, RAM BE Siegmund, OHW Gummin, MA TI Multilayer coatings for narrowband imaging in the extreme ultraviolet SO EUX, X-RAY, AND GAMMA-RAY INSTRUMENTATION FOR ASTRONOMY VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on EUV, X-ray, and Gamma-Ray Instrumentation for Astronomy VIII CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE narrowband imaging; magnetospheric imagery; atmospheric remote sensing; multilayer coatings; extreme ultraviolet AB Multilayer coatings for narrowband imaging in the extreme ultraviolet (EUV) have been designed and prepared. Multilayers were designed to optimize reflectivity at O+ 83.4 Mn spectral line, and simultaneously to reject radiation at 121.6 nn Lyman cc hydrogen line. Al/MgF2/Mo multilayer coatings were prepared and high reflection/suppression ratios at the above wavelengths were measured. The coatings also exhibited a dip in reflectivity at 102.6 nn Lyman beta. The coatings showed some slow degradation over time, but maintained a high reflection/suppression ratio after a few months. Sample cleaning was found effective in restoring a very low reflectivity at 121.6 Mn for samples aged of over 100 days. RP Larruquert, JI (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 717,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2536-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3114 BP 608 EP 616 DI 10.1117/12.283794 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Engineering; Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BJ87K UT WOS:A1997BJ87K00054 ER PT S AU Costen, RC Marchello, JM AF Costen, RC Marchello, JM BE Haulik, T Bailey, V Burton, R TI Sensitivity studies for in-situ automated tape placement of thermoplastic composites SO EVOLVING TECHNOLOGIES FOR THE COMPETITIVE EDGE, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 42nd International SAMPE Symposium and Exhibition on Evolving Technologies for the Competitive Edge (42nd ISSE) CY MAY 04-08, 1997 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE modelling; carbon fibers; thermoplastic polymers; composites; PEEK/C AB This modeling effort seeks to improve the interlaminate bond strength of thermoplastic carbon composites produced by the in-situ automated tape placement (ATP) process. An existing high productivity model is extended to lower values of the Peclet number that correspond to the present operating conditions of the Langley ATP robot. (The Peclet number is the dimensionless ratio of inertial to diffusive heat transfer.) In sensitivity studies, all of the process and material parameters are individually varied. The model yields the corresponding variations in the effective bonding time (EBT) referred to the glass transition temperature. According to reptation theory, the interlaminate bond strength after wetting occurs is proportional to the one-fourth power of EBT. The model also computes the corresponding variations in the thermal input power (TIP) and the mass and volumetric process rates. Process studies show that a 10 percent increase in the consolidation length results in a 20 percent increase in EBT and a 5 percent increase in TIP. A surprising result is that a 10 K decrease in the tooling temperature results in a 25 percent increase in EBT and an 8 percent increase in TIP. Material studies show that a 10 K decrease in glass transition temperature results in an 8 percent increase in EBT and a 8 percent decrease in TIP. A 20 K increase in polymer degradation temperature results in a 23 percent increase in EBT with no change in TIP. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Costen, RC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 13 TC 2 Z9 2 U1 0 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-77-8 J9 INT SAMPE TECH CONF PY 1997 VL 42 BP 33 EP 47 PG 15 WC Engineering, Civil; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA BK24H UT WOS:000071607200004 ER PT S AU Hinkley, JA Messier, BC Marchello, JM AF Hinkley, JA Messier, BC Marchello, JM BE Haulik, T Bailey, V Burton, R TI Effect of pressure in thermoplastic ribbon thermal welding SO EVOLVING TECHNOLOGIES FOR THE COMPETITIVE EDGE, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 42nd International SAMPE Symposium and Exhibition on Evolving Technologies for the Competitive Edge (42nd ISSE) CY MAY 04-08, 1997 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE tow placement; thermoplastic composites; consolidation ID COMPOSITES AB An inexpensive apparatus was designed to simulate some features of on-the-fly thermal welding in heated-head robotic tow placement. Previous studies have shown how ply/ply weld strength depends on weld time/temperature history. The apparatus has now been modified to apply higher contact forces. Welding at pressures up to 1.7 MPa (250 psi) produced more consistent welds and fewer intra-ply voids. This has permitted a study of the conditions required for achieving the limiting ply/ply cohesive strength in simulated tow placement of a polyimide oligomer. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hinkley, JA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-77-8 J9 INT SAMPE TECH CONF PY 1997 VL 42 BP 1209 EP 1216 PG 8 WC Engineering, Civil; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA BK24H UT WOS:000071607200120 ER PT S AU Chuang, KC Waters, JE Hardy-Green, D AF Chuang, KC Waters, JE Hardy-Green, D BE Haulik, T Bailey, V Burton, R TI A high T-g thermosetting polyimide SO EVOLVING TECHNOLOGIES FOR THE COMPETITIVE EDGE, BOOKS 1 AND 2 SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 42nd International SAMPE Symposium and Exhibition on Evolving Technologies for the Competitive Edge (42nd ISSE) CY MAY 04-08, 1997 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE polyimides; oligomers; endcaps; advanced composites ID TEMPERATURE AB Carbon fiber (T-650-35) composites were fabricated from a high T-g thermosetting polyimide (DMBZ-15), using 3,3',4,4'-benzophenone tetracarboxylic acid, dimethyl ester (BTDE) and 2,2'-dimethylbenzidine (DMBZ) with nadic eater (NE) as the endcap. The thermo-oxidative stability as well as the physical properties of the DMBZ-15 polyimide/carbon fiber composite will be compared to that of the PMR-15 composite. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chuang, KC (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 7 Z9 7 U1 0 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-77-8 J9 INT SAMPE TECH CONF PY 1997 VL 42 BP 1283 EP 1290 PG 8 WC Engineering, Civil; Engineering, Mechanical; Materials Science, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA BK24H UT WOS:000071607200128 ER PT J AU Hudec, R Spurny, P Florian, J Bocek, J Tichy, M Ticha, J Vyskocil, L Wenzel, W Barthelmy, S Cline, T Gehrels, N Fishman, G Kouveliotou, C Meegan, C Mutafov, A AF Hudec, R Spurny, P Florian, J Bocek, J Tichy, M Ticha, J Vyskocil, L Wenzel, W Barthelmy, S Cline, T Gehrels, N Fishman, G Kouveliotou, C Meegan, C Mutafov, A TI European Observation Network: Ground-based support for gamma-ray satellites SO EXPERIMENTAL ASTRONOMY LA English DT Article; Proceedings Paper CT 4th Meeting of the European-Astronomical-Society / Italian-Astronomical-Society on Progress in European Astrophysics - New Instruments and Technologies CY SEP 25-29, 1995 CL CATANIA, ITALY SP European Astronom Soc, Italian Astronom Soc AB We present first preliminary results obtained with the European Observation Network consisting of 9 observatories in the Czech Republic, Germany and Bulgaria. We also discuss related problems such as the background of unknown variable stars and suggest a strategy for work in this area. C1 Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. Klet Observ, CZ-37001 Ceske Budejovice, Czech Republic. Upice Observ, CZ-54232 Upice, Czech Republic. Sternwarte Sonneberg, D-96515 Sonneberg, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Astron Observ, BG-1504 Sofia, Bulgaria. RP Hudec, R (reprint author), Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Spurny, Pavel/G-9044-2014; Hudec, Rene/G-9018-2014 NR 10 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 0922-6435 J9 EXP ASTRON JI Exp. Astron. PY 1997 VL 7 IS 4 BP 319 EP 323 DI 10.1023/A:1007933102971 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YZ683 UT WOS:000072280100008 ER PT J AU Layne, CS McDonald, PV Bloomberg, JJ AF Layne, CS McDonald, PV Bloomberg, JJ TI Neuromuscular activation patterns during treadmill walking after space flight SO EXPERIMENTAL BRAIN RESEARCH LA English DT Article DE electromyography; adaptation; space flight; locomotion; human ID GAIT ANALYSIS; EMG PROFILES; LOCOMOTION; COMPUTER; MICROGRAVITY; PERFORMANCE; MUSCLES; HUMANS AB Astronauts adopt a variety of neuromuscular control strategies during space flight that are appropriate for locomoting in that unique environment, but are less than optimal upon return to Earth. We report here the first systematic investigation of potential adaptations in neuromuscular activity patterns associated with post flight locomotion. Astronaut-subjects were tasked with walking on a treadmill at 6.4 km/h while fixating a visual target 30 cm away from their eyes after space flights of 8-15 days. Surface electromyography was collected from selected lower limb muscles and normalized with regard to mean amplitude and temporal relation to heel strike. In general, high correlations (more than 0.80) were found between preflight and postflight activation waveforms for each muscle and each subject; however, relative activation amplitude around heel strike and toe off was changed as a result of flight. The level of muscle cocontraction and activation variability, and the relation ship between the phasic characteristics of the ankle musculature in preparation for toe off also were altered by space flight. Subjects also reported oscillopsia during treadmill walking after flight. These findings indicate that, after space flight, the sensory-motor system can generate neuromuscular-activation strategies that permit treadmill walking, but subtle changes in lower-limb neuromuscular activation are present that may contribute to increased lower limb kinematic variability and oscillopsia also present during postflight walking. C1 NASA, LYNDON B JOHNSON SPACE CTR, LIFE SCI RES LABS, HOUSTON, TX 77058 USA. RP Layne, CS (reprint author), KRUG LIFE SCI, MOVEMENT & COORDINAT LAB, 1290 HERCULES, SUITE 120, HOUSTON, TX 77058 USA. NR 35 TC 54 Z9 56 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0014-4819 J9 EXP BRAIN RES JI Exp. Brain Res. PD JAN PY 1997 VL 113 IS 1 BP 104 EP 116 DI 10.1007/BF02454146 PG 13 WC Neurosciences SC Neurosciences & Neurology GA WE157 UT WOS:A1997WE15700011 PM 9028779 ER PT J AU Crouser, PD Bethea, MD Merat, FL AF Crouser, PD Bethea, MD Merat, FL TI Unattenuated tracer particle extraction through time-averaged, background image subtraction with outlier rejection SO EXPERIMENTS IN FLUIDS LA English DT Article AB Fluid-flow analysis using particle tracking seeks to assign velocity vectors to sequences of still images (tracks) of particles suspended in a transparent fluid or gas. This requires that high quality particle images be obtained from a system of moving particles. In practice, however, the images are contaminated by a variety of noise sources which must be removed before tracking can be performed. The traditional approach to prefiltering, which is being used in commercially-available systems, is to perform background subtraction in concert with some form of thresholding and/or image stretching. Unfortunately, these methods can attenuate particle images so badly that valid track yields are significantly reduced. In place of these methods, we present a non-attenuating background subtraction method with outlier rejection together with a non-attenuating substitute for thresholding. These algorithms have been tested on real track data and can recover virtually all images of particles in suspension with very little attenuation of particle-image intensity. C1 NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,DEPT ELECT ENGN,CLEVELAND,OH 44135. RP Crouser, PD (reprint author), CASE WESTERN RESERVE UNIV,DEPT COMP ENGN & SCI,CLEVELAND,OH 44135, USA. NR 11 TC 2 Z9 2 U1 5 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD JAN PY 1997 VL 22 IS 3 BP 220 EP 228 DI 10.1007/s003480050040 PG 9 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA WE816 UT WOS:A1997WE81600005 ER PT S AU Mather, JC Seery, BD Stockman, HS Bely, PY AF Mather, JC Seery, BD Stockman, HS Bely, PY GP EUROPEAN SPACE AGCY TI The Next Generation Space Telescope (NGST) - Science and technology SO FAR INFRARED AND SUBMILLIMETRE UNIVERSE: AN ESA SYMPOSIUM DEVOTED TO THE FAR INFRARED AND SUBMILLIMETRE TELESCOPE (FIRST) MISSION SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT ESA Symposium on the Far InfraRed and Submillimetre Universe CY APR 15-17, 1997 CL INST RADIO ASTRON MILLIMETR, GRENOBLE, FRANCE SP European Space Agcy HO INST RADIO ASTRON MILLIMETR AB The scientific requirements and the implications for the instruments and telescope design for the Next Generation Space Telescope are described. One candidate concept is a deployable 8 meter diameter telescope optimized for the near infrared region (1-5 mu m), but with instruments capable of observing from the visible all the way to 30 mu m. The observatory is radiatively cooled to about 30 K and could be launched on an Atlas II-AS to the Lagrange Point L2. RP Mather, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 685,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-287-7 J9 ESA SP PUBL PY 1997 VL 401 BP 213 EP 218 PG 6 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BJ82Z UT WOS:A1997BJ82Z00031 ER PT S AU Bock, JJ LeDuc, HG Lange, AE Zmuidzinas, J AF Bock, JJ LeDuc, HG Lange, AE Zmuidzinas, J GP EUROPEAN SPACE AGCY TI A monolithic bolometer array suitable for first SO FAR INFRARED AND SUBMILLIMETRE UNIVERSE: AN ESA SYMPOSIUM DEVOTED TO THE FAR INFRARED AND SUBMILLIMETRE TELESCOPE (FIRST) MISSION SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT ESA Symposium on the Far InfraRed and Submillimetre Universe CY APR 15-17, 1997 CL INST RADIO ASTRON MILLIMETR, GRENOBLE, FRANCE SP European Space Agcy HO INST RADIO ASTRON MILLIMETR AB We are developing arrays of infrared bolometers that are suitable for use on FIRST. The array architecture is based on the silicon nitride micromesh (''spider-web'') bolometer that is currently baselined for use on Planck. The micromesh architecture allows each pixel to be efficiently coupled to one or both polarizations and to one or more spatial modes of radiation. Relative to a conventional absorber consisting of a solid metalized dielectric, the micromesh structure offers i) 98% reduction in cosmic ray cross-section, ii) 95% reduction in absorber heat capacity, iii) improved thermal isolation from the heat sink, and iv) reduced microphonic sensitivity. Large format arrays of micromesh bolometers can be fabricated on a single silicon wafer. Radiation is coupled to the detectors by a close-packed array of feedhorns which control the field-of-view of each detector and shield against electromagnetic interference. A variety of thermistor technologies can be implemented on the micromesh structures. Detectors with small (300 x 100 x 20 mu m) Neutron Transmutation Doped Ge thermistors that are Indium bump-bonded to the micromesh achieve electrical NEPs and time constants of 2 x 10(-18) W/root Hz and 65 ms at 100 mK and 1.2 x 10(-17) W/root Hz and 100 ms at 300 mK. The very low thermal conductivity of the silicon nitride supports in principle allows sensitivities of 3 x 10(-19) W/root Hz at 100 mK and 3 x 10(-18) W/root Hz at 300 mK. Such devices would have an impractically long time constant if coupled to a NTD Ge thermistor, but can achieve time constants of order 1 ms using a device that provides strong electro-thermal feedback, such as a superconducting film voltage-biased at its transition edge. We are currently developing micromesh structures coupled to transition-edge sensors and read out by a SQUID amplifier. If these devices are successful, then the relatively large cooling power available at 300 mK may enable a SQUID-based multiplexer to be integrated on the same wafer with the array, creating a monolithic, fully multiplexed 2-dimensional array with relatively few electrical connections to the sub-Kelvin stage. RP Bock, JJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-287-7 J9 ESA SP PUBL PY 1997 VL 401 BP 349 EP 352 PG 4 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BJ82Z UT WOS:A1997BJ82Z00063 ER PT S AU McGrath, WR Skalare, A Karasik, B Gaidis, M Bumble, B LeDuc, HG Burke, PJ Schoelkopf, RJ Prober, DE Verghese, S McIntosh, KA Brown, ER AF McGrath, WR Skalare, A Karasik, B Gaidis, M Bumble, B LeDuc, HG Burke, PJ Schoelkopf, RJ Prober, DE Verghese, S McIntosh, KA Brown, ER GP EUROPEAN SPACE AGCY TI Superconductive hot electron mixers with ultra-wide RF bandwidth for heterodyne receiver applications up to 3 THz SO FAR INFRARED AND SUBMILLIMETRE UNIVERSE: AN ESA SYMPOSIUM DEVOTED TO THE FAR INFRARED AND SUBMILLIMETRE TELESCOPE (FIRST) MISSION SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT ESA Symposium on the Far InfraRed and Submillimetre Universe CY APR 15-17, 1997 CL INST RADIO ASTRON MILLIMETR, GRENOBLE, FRANCE SP European Space Agcy HO INST RADIO ASTRON MILLIMETR AB We report on the development of quasioptical Nb hot-electron bolometer mixers for heterodyne receivers at 1.2 THz and 2.5 THz. The devices have submicron in-plane sizes, thus exploiting diffusion as the electron cooling mechanism. Quasioptical mixer circuits have been developed with planar double-dipole or twin-slot antennas. Specially designed THz test systems which avoid atmospheric absorption were used in the experiments. The measured (DSB) receiver noise temperatures are 1900K at 1.2 THz, with an estimated mixer noise temperature of 950 K, and 2750 K at 2.5 THz, with an estimated mixer noise temperature of approximate to 900 K. These results demonstrate the low-noise operation of the diffusion-cooled bolometer mixer over a wide range of frequencies up to at least 2.5 THz. RP McGrath, WR (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,MAIL STOP 168-314,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Gaidis, Michael/D-3327-2013; Burke, Peter/F-3308-2010 NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-287-7 J9 ESA SP PUBL PY 1997 VL 401 BP 401 EP 404 PG 4 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BJ82Z UT WOS:A1997BJ82Z00076 ER PT S AU Newman, JC AF Newman, JC BE Underwood, JH Macdonald, BD Mitchell, MR TI The merging of fatigue and fracture mechanics concepts: A historical perspective SO FATIGUE AND FRACTURE MECHANICS: 28TH VOL SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 28th National Symposium on Fatigue and Fracture Mechanics CY JUN 25-27, 1996 CL SARATOGA SPRINGS, NY SP ASTM Comm E 08 Fatigue & Fracture, USA Res Off DE fatigue; fracture mechanics; microstructure; cracks; surface cracks; stress-intensity factor; J-integral; fatigue crack growth; crack closure; elasticity; plasticity; finite element method; constraint AB The seventh Jerry L. Swedlow Memorial Lecture presents a review of some of the technical developments, that have occurred during the past 40 years, which have led to the merger of fatigue and fracture mechanics concepts. This review is made from the viewpoint of ''crack propagation.'' As methods to observe the ''fatigue'' process have improved, the formation of fatigue micro-cracks have been observed earlier in life and the measured crack sizes have become smaller. These observations suggest that fatigue damage can now be characterized by ''crack size.'' In parallel, the crack-growth analysis methods, using stress-intensity factors, have also improved. But the effects of material inhomogeneities, crack-fracture mechanisms, and nonlinear behavior must now be included in these analyses. The discovery of crack-closure mechanisms, such as plasticity, roughness, and oxide/corrosion/fretting product debris, and the use of the effective stress-intensity factor range, has provided an engineering tool to predict small-and large-crack-growth rate behavior under service loading conditions. These mechanisms have also provided a rationale for developing new, damage-tolerant materials. This review suggests that small-crack growth behavior should be viewed as typical behavior, whereas large-crack threshold behavior should be viewed as the anomaly. Small-crack theory has unified ''fatigue'' and ''fracture mechanics'' concepts; and has bridged the gap between safe-life and durability/damage-tolerance design concepts. RP Newman, JC (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 7 Z9 7 U1 1 U2 4 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 SN 1071-5827 BN 0-8031-2410-4 J9 AM SOC TEST MATER PY 1997 VL 1321 BP 3 EP 51 DI 10.1520/STP12300S PG 49 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BJ51Y UT WOS:A1997BJ51Y00001 ER PT J AU Piascik, RS Newman, JC Underwood, JH AF Piascik, RS Newman, JC Underwood, JH TI The extended compact tension specimen SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE extended compact tension specimen; compliance; stress-intensity factor AB An extended compact tension, EC(T), specimen has been developed for fatigue and fracture testing. The EC(T) specimen exhibits distinct advantages compared to other cracked specimen configurations, i.e., standard compact tension, single-edge crack, and middle-crack tension specimens. Documented herein are stress-intensity factor and compliance expressions for the EC(T) specimen. C1 USA,ARMAMENT RE&E CTR,BENET LABS,WATERVLIET,NY 12189. RP Piascik, RS (reprint author), NASA,LANGLEY RES CTR,MECH MAT BRANCH,HAMPTON,VA 23681, USA. NR 3 TC 18 Z9 19 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PY 1997 VL 20 IS 4 BP 559 EP 563 DI 10.1111/j.1460-2695.1997.tb00287.x PG 5 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA WV711 UT WOS:A1997WV71100004 ER PT J AU Zhao, W Newman, JC Sutton, MA Wu, XR Shivakumar, KN AF Zhao, W Newman, JC Sutton, MA Wu, XR Shivakumar, KN TI Stress intensity factors for corner cracks at a hole by a 3-D weight function method with stresses from the finite element method SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE stress intensity factors; corner cracks; weight function method; stress concentrations ID SURFACE CRACKS; SEMICIRCULAR NOTCH; ELLIPTIC CRACKS; ELASTIC PLATES; GRADIENTS; EDGE; COMPUTATION; TENSION; BODIES; FIELDS AB Stress intensity factors for quarter-elliptical corner cracks emanating from a circular hole are determined using a 3-D weight function method combined with a 3-D finite element method. The 3-D finite element method is used to analyze uncracked configurations and provide stress distributions in the region where a crack is likely to occur. Using this stress distribution as input, the 3-D weight function method is used to determine stress intensity factors. Three different loading conditions, i.e. remote tension, remote bending and wedge loading, are considered for a wide range of geometrical parameters. The significance of using 3-D uncracked stress distributions is studied. Comparisons are made with solutions available in the literature. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. INST AERONAUT MAT,BEIJING 100095,PEOPLES R CHINA. N CAROLINA AGR & TECH STATE UNIV,GREENSBORO,NC 27410. RP Zhao, W (reprint author), UNIV S CAROLINA,COLUMBIA,SC 29208, USA. NR 48 TC 13 Z9 13 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PY 1997 VL 20 IS 9 BP 1255 EP 1267 DI 10.1111/j.1460-2695.1997.tb01485.x PG 13 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XZ723 UT WOS:A1997XZ72300002 ER PT B AU Duarte, LS AF Duarte, LS BE Schmieder, B Iniesta, JCD Vazquez, M TI The SOHO archive SO FIRST ADVANCES IN SOLAR PHYSICS EUROCONFERENCE : ADVANCES IN THE PHYSICS OF SUNSPOTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1st Euroconference on Advances in the Physics of Sunspots CY OCT 02-06, 1996 CL PUERTO DE LA CRUZ, SPAIN SP European Union, Spanish Direcc Gen Ensenanza Super, Canarian Acad Sci, Cabildo Insular Santa Cruz Tenerife, Ayuntamiento Puerto Cruz, Observ Paris, Inst Astrofis Canarias AB This paper presents an overview of the Solar and Heliospheric Observatory (SOHO) archive built at NASA Goddard Space Flight Center from both the architectural and the end user point of view. The archive, which started operating on August 1996, provides homogeneus access to the data collected by the SOHO payload and support to joint observing programs of several of the SORO instruments as well as to campaigns carried out together with other space or ground based observatories. C1 NASA, Goddard Space Flight Ctr, European Space Agcy, Dept Space Sci, Greenbelt, MD 20771 USA. RP Duarte, LS (reprint author), NASA, Goddard Space Flight Ctr, European Space Agcy, Dept Space Sci, Code 682-3, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-38-4 J9 ASTR SOC P PY 1997 VL 118 BP 378 EP 381 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK79Y UT WOS:000073439600054 ER PT B AU Duarte, LS Fleck, B Bentley, R AF Duarte, LS Fleck, B Bentley, R BE Schmieder, B Iniesta, JCD Vazquez, M TI The Whole Sun Catalogue SO FIRST ADVANCES IN SOLAR PHYSICS EUROCONFERENCE : ADVANCES IN THE PHYSICS OF SUNSPOTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1st Euroconference on Advances in the Physics of Sunspots CY OCT 02-06, 1996 CL PUERTO DE LA CRUZ, SPAIN SP European Union, Spanish Direcc Gen Ensenanza Super, Canarian Acad Sci, Cabildo Insular Santa Cruz Tenerife, Ayuntamiento Puerto Cruz, Observ Paris, Inst Astrofis Canarias AB To maximize the scientific outcome of the wealth of solar observations available, it would be extremely useful to have a complete, central catalogue giving some basic information such as 'where, when, what' about all solar observations made. This paper presents a proposal for such a catalogue based on the infrastructure developed for the SOHO Archive, but being independent of it. Our goal is to refine this proposal with the help of the JOSO group and to implement it by 1997. C1 NASA, Goddard Space Flight Ctr, European Space Agcy, Dept Space Sci, Greenbelt, MD 20771 USA. RP Duarte, LS (reprint author), NASA, Goddard Space Flight Ctr, European Space Agcy, Dept Space Sci, Code 682-3, Greenbelt, MD 20771 USA. RI Fleck, Bernhard/C-9520-2012 NR 0 TC 6 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-38-4 J9 ASTR SOC P PY 1997 VL 118 BP 382 EP 384 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK79Y UT WOS:000073439600055 ER PT S AU Satyapal, S Luhman, ML Fischer, J Greenhouse, MA Wolfire, MG AF Satyapal, S Luhman, ML Fischer, J Greenhouse, MA Wolfire, MG GP ESA TI Photoionization modeling of the LWS fine-structure lines in IR bright galaxies SO FIRST ISO WORKSHOP ON ANALYTICAL SPECTROSCOPY: WITH SWS, LWS, PHT-S, AND CAM-CVF SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st ISO Workshop on Analytical Spectroscopy CY OCT 06-08, 1997 CL MADRID, SPAIN SP European Space Agcy DE galaxies, starburst, active; infrared, galaxies; infrared, ISM, lines and bands AB Stellar evolutionary synthesis models combined with photoionization and photodissociation region models are used to self-consistently model LWS fine structure lines from IR luminous galaxies. Starburst and active galactic nuclei (AGN) models are presented and the effects of dust in the ionized region are examined. These models provide diagnostics of, for example, the age of the starburst and the dominant luminosity source. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Satyapal, S (reprint author), Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-676-7 J9 ESA SP PUBL PY 1997 VL 419 BP 293 EP 294 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK66F UT WOS:000072989100057 ER PT B AU Ruzicka, K AF Ruzicka, K BE Martin, RE Collette, RL Salvin, JW TI NMFS sensory program SO FISH INSPECTION, QUALITY CONTROL AND HACCP: A GLOBAL FOCUS LA English DT Proceedings Paper CT 2nd International Conference on Fish Inspection and Quality Control CY MAY 19-24, 1996 CL ARLINGTON, VA SP Natl Fisheries Inst, US FDA, UN Food & Agr Org, US Natl Marine Fisheries Serv, Canadian Dept Fihseries & Oceans, Fisheries Council Canada, Joseph Slavin & Associates, GEM Biomed Inc AB Seafood quality is paramount to consumers and sensory evaluation is an integral part of monitoring for quality. In a recent survey conducted across the country, we asked consumers why they didn't buy more seafood. They consistently told us that the number one reason was due to inconsistent quality and too high prices. The U.S. National Marine Fisheries Service offers a voluntary seafood inspection program; and one of the services NMFS provides is quality inspection for imported and exported products. A key element in certifying quality rests in effective objective sensory evaluation. Sensory evaluation as a science can be objective, sensitive and reliable. The objective of sensory training is to increase consistency of product assessments from one analyst to another; in other words, to have analysts act as one sensory unit. Sensory science provides better tools to do that. C1 Natl Marine Fisheries Serv, NE Inspect Branch, Gloucester, MA 01930 USA. RP Ruzicka, K (reprint author), Natl Marine Fisheries Serv, NE Inspect Branch, 1 Blackburn Dr, Gloucester, MA 01930 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-546-3 PY 1997 BP 494 EP 497 PG 2 WC Fisheries; Food Science & Technology SC Fisheries; Food Science & Technology GA BQ50E UT WOS:000088535800058 ER PT B AU Rainosek, AP AF Rainosek, AP BE Martin, RE Collette, RL Salvin, JW TI Inherent risks in acceptance sampling SO FISH INSPECTION, QUALITY CONTROL AND HACCP: A GLOBAL FOCUS LA English DT Proceedings Paper CT 2nd International Conference on Fish Inspection and Quality Control CY MAY 19-24, 1996 CL ARLINGTON, VA SP Natl Fisheries Inst, US FDA, UN Food & Agr Org, US Natl Marine Fisheries Serv, Canadian Dept Fihseries & Oceans, Fisheries Council Canada, Joseph Slavin & Associates, GEM Biomed Inc AB Lot acceptance sampling plans are extensively used in practice as a means of gathering data to assist in determine whether or not a product produced (usually on a lot-by-lot basis) satisfies one or more specifications. The results obtained from sampling are then used to judge the quality/safety condition of the total product (lot) under evaluation. Based on this inferential process, there always exists the possibility of making an incorrect decision on the actual lot status, i.e., rejection of a conforming ("good") lot or acceptance of a nonconforming ("bad") lot. In particular, an inadequate awareness of the inherent limitations of a sampling plan may lead to an unjustified sense of security by those responsible for its use. The possibility that a sampling plan will lead to an incorrect decision on the actual lot status can be described by that plan's performance characteristics, i.e., the chance of accepting lots that vary in quality. This paper will examine the performance characteristics of selected sampling plans currently in use by the Food and Drug Administration, National Marine Fisheries Service, Coder Alimentarius, and the International Commission on Microbiological Specifications for Foods. C1 Natl Marine Fisheries Serv, Pascagoula, MS 39568 USA. RP Rainosek, AP (reprint author), Natl Marine Fisheries Serv, PO Drawer 1207, Pascagoula, MS 39568 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-546-3 PY 1997 BP 530 EP 537 PG 2 WC Fisheries; Food Science & Technology SC Fisheries; Food Science & Technology GA BQ50E UT WOS:000088535800063 ER PT B AU Winters, RS AF Winters, RS BE Martin, RE Collette, RL Salvin, JW TI Automated computerization of laboratory analyses SO FISH INSPECTION, QUALITY CONTROL AND HACCP: A GLOBAL FOCUS LA English DT Proceedings Paper CT 2nd International Conference on Fish Inspection and Quality Control CY MAY 19-24, 1996 CL ARLINGTON, VA SP Natl Fisheries Inst, US FDA, UN Food & Agr Org, US Natl Marine Fisheries Serv, Canadian Dept Fihseries & Oceans, Fisheries Council Canada, Joseph Slavin & Associates, GEM Biomed Inc AB With today's corporate and government downsizing and bottom line accountability, automation and computerization of analytical data are becoming a necessity. Fewer personnel, increased workloads and the financial pressures from management to show a profit are the principal driving forces behind increased computer automation of laboratory analyses. The method of automating depends on management and laboratory needs. Automated computerization of laboratory analyses may be as simple as using a personal computer (PC), or as complex as adding a Laboratory Information Management System (LIMS). Regardless of the automated system chosen, management and end user must ensure that the system meets the analytical requirements of the laboratory. For a laboratory to operate under quality management standards proper system and software validation is essential. C1 Natl Marine Fisheries Serv, Pascagoula, MS 39568 USA. RP Winters, RS (reprint author), Natl Marine Fisheries Serv, PO Drawer 1207, Pascagoula, MS 39568 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-546-3 PY 1997 BP 577 EP 581 PG 3 WC Fisheries; Food Science & Technology SC Fisheries; Food Science & Technology GA BQ50E UT WOS:000088535800069 ER PT J AU Parrish, FA DeMartini, EE Ellis, DM AF Parrish, FA DeMartini, EE Ellis, DM TI Nursery habitat in relation to production of juvenile pink snapper, Pristipomoides filamentosus, in the Hawaiian Archipelago SO FISHERY BULLETIN LA English DT Article ID FISHES; COMMUNITY; ESTUARIES AB Densities of juveniles of the Hawaiian deepwater snapper Pristipomoides filamentosus were surveyed for 3 years in relation to their demersal environment at an east Oahu study site. Juveniles settled annually to spatially stable aggregations, occupying expanses of uniform sedimentary habitat. Habitat data were collected and used in a logistic regression model to predict correctly 68% of the juveniles' spatial variability. Premium habitat was identified as a sediment bottom, free of relief, and close to focused sources of drainage (reef platforms, embayments, and anthropogenic sources) in adjacent shallows. Surveys for juveniles elsewhere on insular slopes of the Hawaiian Archipelago indicated low juvenile abundance except at infrequent locations close to point sources of coastal drainage. Estimates of recruit production, based on densities of juveniles from other than premium habitat, were a small fraction of the recruits needed (calculated from catch) to account for the fishery's current landings of adult snappers. The 68-fold higher juvenile abundance at premium habitat can reconcile this difference, indicating that such infrequent high-quality habitat is an important (perhaps critical) fishery resource. RP Parrish, FA (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822, USA. NR 37 TC 10 Z9 10 U1 1 U2 3 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 JAN PY 1997 VL 95 IS 1 BP 137 EP 148 PG 12 WC Fisheries SC Fisheries GA WK139 UT WOS:A1997WK13900012 ER PT B AU Biswas, R Oliker, L AF Biswas, R Oliker, L GP IEEE COMP SOC TI Load balancing sequences of unstructured adaptive grids SO FOURTH INTERNATIONAL CONFERENCE ON HIGH-PERFORMANCE COMPUTING, PROCEEDINGS LA English DT Proceedings Paper CT 4th International Conference on High-Performance Computing (HiPC 97) CY DEC 18-21, 1997 CL BANGALORE, INDIA SP IEEE Comp Soc, Tech Comm Parallel Proc, ACM SIGARCH, Supercomp Educ & Res Ctr, India, Ctr Dev Adv Comp, India, CSIR Ctr Math Modelling & Comp Simulat, India, Tata Inst Fundamental Res, India, Indian Inst Technol RP Biswas, R (reprint author), NASA,AMES RES CTR,MRJ TECHNOL SOLUT,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8067-9 PY 1997 BP 212 EP 217 DI 10.1109/HIPC.1997.634495 PG 6 WC Computer Science, Theory & Methods SC Computer Science GA BJ88F UT WOS:A1997BJ88F00033 ER PT B AU Newman, JC Dodds, RH AF Newman, JC Dodds, RH BE Rossmanith, HP TI From brittle to elastic-plastic fracture mechanics SO FRACTURE RESEARCH IN RETROSPECT: AN ANNIVERSARY VOLUME IN HONOUR OF GEORGE R. IRWIN'S 90TH BIRTHDAY LA English DT Proceedings Paper CT Special Session on Fracture Research in Retrospect, in Honour of the 90th Birthday of George Rankin Irwin, at the 9th International Congress of Fracture (ICF-9) CY APR, 1997 CL SYDNEY, AUSTRALIA DE cracks; stress-intensity factor; plasticity; fracture; J-integral; CTOD; CTOA; microstructure; aluminum alloy; steel AB This paper is written in honour of Dr George R. Irwin, in celebration of his 90th birthday, and reviews several key developments in fracture mechanics from his 'stress-intensity factor' concept to the advanced, non-linear fracture simulations performed today. Applications of Irwin's early concepts, by other researchers, to characterise the fracture of metallic materials under brittle and elastic-plastic conditions are discussed. The progression from single-parameter to two-parameter fracture mechanics, focusing on constraint effects, is highlighted. From these initial studies, two advanced fracture analysis methods, which employ detailed finite-element modelling to predict ductile tearing, have evolved. These methods utilise a local criterion for material separation: either a void growth and coalescence model or a critical crack-tip opening angle (or displacement) parameter. Recently developed key results from these approaches are presented and discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU A A BALKEMA PUBLISHERS PI LEIDEN PA SCHIPHOLWEG 107C, PO BOX 447, 2316 XC LEIDEN, NETHERLANDS BN 90-5410-679-4 PY 1997 BP 265 EP 282 PG 18 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BK60J UT WOS:000072713200019 ER PT B AU Montgomery, EE AF Montgomery, EE BE OShea, PG Bennett, HE TI Beamed energy transportation initiatives at MSFC SO FREE-ELECTRON LASER CHALLENGES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Electron Laser Challenges CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE laser; rocket; upper stage; propulsion; launch vehicle; combined cycle AB A historical summary review of recent component technology advancements within NASA's program for launch vehicles and space transfer systems utilizing high average power laser beams sets the foundation of this paper. Research into highly speculative propulsion alternatives is being sponsored by the Advanced concepts branch of the Advanced Space Transportation Program. Topics include such high payoff technologies as an energy beam fired combined cycle rocket engine for launch of small payloads from the ground to space and high specific impulse upper stage propulsion utilizing energy supplied from photovoltaic arrays illuminated with a ground based laser. The NASA Beamed Energy Transportation (BET) development plan will be described. RP Montgomery, EE (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PS02,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2399-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 2988 BP 272 EP 279 DI 10.1117/12.274391 PG 8 WC Optics SC Optics GA BH88P UT WOS:A1997BH88P00031 ER PT B AU Wilson, KE Lesh, JR Araki, K Arimoto, Y AF Wilson, KE Lesh, JR Araki, K Arimoto, Y BE Mecherle, GS TI Overview of the Ground-to-Orbit Lasercom Demonstration SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE Lasercom; ETS-VI; optical communications AB The Ground-to-Orbit Lasercom Demonstration conducted between the ETS-VI spacecraft and the ground station at JPL's Table Mountain Facility, Wrightwood CA was the first ground-to-space two-way optical communications experiment. The demonstration was conducted over a period of seven months and required simultaneous and cooperative operations by team members in Tokyo and California. A key objective was to measure the atmospheric attenuation and seeing during the demonstration to validate the performance of the optical link. The telemetry downlinked from the laser communications equipment provided information on the in-orbit performance of the onboard laser transmitter. Downlinked PN data enabled measurement of bit error rates. BERs as low as 10(-4) were measured on the uplink and 10(-5) on the downlink. Measured signal powers (corrected for measured atmospheric attenuation) agreed with theoretical predictions. RP Wilson, KE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91101, USA. RI Institute of Chemistry - USP, Dept. of Chemistry/B-8988-2012 NR 0 TC 15 Z9 16 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 23 EP 30 DI 10.1117/12.273703 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00003 ER PT B AU Jeganathan, M Toyoshima, M Wilson, K James, J Xu, G Lesh, J AF Jeganathan, M Toyoshima, M Wilson, K James, J Xu, G Lesh, J BE Mecherle, GS TI Data analysis results from the GOLD experiments SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE free-space optical communication; atmospheric scintillation; multi-beam uplink; downlink; aperture averaging; laser communication; link budget AB Analyses of uplink and downlink data from recent free-space optical communications experiments carried out between Table Mountain Facility (near Pasadena, CA) and the Japanese ETS-VI satellite are presented. Fluctuations in signal power collected by the satellite's laser communication experiment (LCE) due to atmospheric scintillation and its amelioration using multiple uplink beams are analyzed and compared to experimental data. Downlink data was analyzed to determine the cause of a larger than expected variation in signal strength. In spite of the difficulty in deconvolving atmospheric effects from pointing errors and spacecraft vibration, experimental data clearly indicate significant improvement in signal reception on the uplink with multiple beams, and the need for stable pointing to establish high data rate optical communications. RP Jeganathan, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 19 Z9 19 U1 2 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 70 EP 81 DI 10.1117/12.273711 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00008 ER PT B AU Yan, TY Jeganathan, M Lesh, JR AF Yan, TY Jeganathan, M Lesh, JR BE Mecherle, GS TI Progress on the development of the optical communications demonstrator SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers AB The Optical Communications Demonstrator (OCD) is a laboratory-based lasercom demonstration terminal designed to validate several key technologies, including beacon acquisition, high bandwidth tracking, precision beam pointing, and point-ahead compensation functions. It has been under active development over the past few years. The instrument uses a CCD array detector for both spatial acquisition and high-bandwidth tracking, and a fiber coupled laser transmitter. The array detector tracking concept provides wide field-of-view acquisition and permits effective platform jitter compensation and point-ahead control using only one steering mirror. The use of a fiber-coupled transmitter modularizes the transmitter design and de-couples its thermal management problems from the main system optics. The reduction in design complexity can lead to a reduced system cost and an improved system reliability. This paper describes recent progress on the development of the OCD terminal. RP Yan, TY (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 3 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 94 EP 101 DI 10.1117/12.273684 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00010 ER PT B AU Jeganathan, M Erickson, D AF Jeganathan, M Erickson, D BE Mecherle, GS TI An overview of the Atmospheric Visibility Monitoring (AVM) Program SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE atmospheric visibility; atmospheric transmission; atmospheric attenuation; cloud-cover statistics; free-space optical communication; laser communication; Link Budget AB The objective of the Atmospheric Visibility Monitoring (AVM) program at the Jet Propulsion Laboratory is to obtain atmospheric transmission statistics data to support free-space optical communications experiments and missions. Atmospheric transmission data is collected through a set of three autonomous systems, all located in the southwestern US, that observe the stars throughout the year. Data from the three sites are collected and processed on a regular basis to obtain cumulative distribution functions of atmospheric attenuation at different spectral regions. These data will be used to determine site diversity information. In addition, work is underway to build a database of atmospheric transmission data collected by the AVM program and to upgrade the AVM systems to obtain improved data at the important 1.06 mu m wavelength. RP Jeganathan, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 114 EP 120 DI 10.1117/12.273686 PG 7 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00012 ER PT B AU Wilson, KE Page, N Biswas, A Hemmati, H Masters, K Erickson, D Lesh, JR AF Wilson, KE Page, N Biswas, A Hemmati, H Masters, K Erickson, D Lesh, JR BE Mecherle, GS TI The lasercom test and evaluation station for flight terminal evaluation SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE laser terminal; optical; lasercom; laser transmitter; divergence; testbed AB Full-up pre-launch characterization of a lasercom terminal's communications and acquisition/tracking subsystems can provide quantitative characterization of the terminal and better realize the benefits of any demonstration. The lasercom test and evaluation station (LTES) being developed at NASA/JPL is a high quality optical system that will measure the key characteristics of lasercom terminals that operate over the visible and near-infrared spectral region. The LTES's large receiving aperture will accommodate terminals up to 20 cm. in diameter. The unit has six optical channels and it measures far-field beam pattern, divergence, data rates up to 1.4 Gbps and bit-error rates as low as 10(-9). It also measures the output power of the laser-terminal's beacon and communications channels. The 1 kHz frame rate camera in LTES's acquisition channel measures the point-ahead angle of the laser communications terminal to a resolution of 1 mu rad. When combined with the data channel detection, the acquisition channel measures; acquisition and reacquisition times with a 1 ms resolution. RP Wilson, KE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 3 Z9 3 U1 1 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 152 EP 158 DI 10.1117/12.273690 PG 7 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00016 ER PT B AU Hemmati, H Layland, J Lesh, J Wilson, K Sue, M Rascoe, D Lansing, F Wilhelm, M Harcke, L Chen, C Feria, Y AF Hemmati, H Layland, J Lesh, J Wilson, K Sue, M Rascoe, D Lansing, F Wilhelm, M Harcke, L Chen, C Feria, Y BE Mecherle, GS TI Comparative study of optical and RF communication systems for a Mars mission .2. Unified value metrics SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies IX CY FEB 13-14, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers AB In this Part-II report of the Advanced Communications Benefits study, two critical metrics for comparing the benefits of utilizing X-band, Ka-band and Optical frequencies for supporting generic classes of Martian exploration missions have been evaluated. The first of these is the overall equivalent communications system mass on the spacecraft. The second comparison metric is the overall cost impact. This ''overall'' cost assessment has considered the costs for both the spacecraft end of the link and the ground end. In both cases the metrics indicate that higher frequency communication bands have favorable mass and cost, particularly at higher data volumes transmitted daily to the earth. The same metrics are also applied to telecommunication for a hypothetical Neptune mission, extrapolating from the designs for the Mars case. RP Hemmati, H (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2401-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 2990 BP 200 EP 214 DI 10.1117/12.273697 PG 15 WC Engineering, Aerospace; Remote Sensing; Optics; Telecommunications SC Engineering; Remote Sensing; Optics; Telecommunications GA BH74Z UT WOS:A1997BH74Z00022 ER PT S AU Coleman, C AF Coleman, C GP EP INNOVATIONS TI Women in engineering: A personal success story SO FRONTIERS IN EDUCATION 1997 - 27TH ANNUAL CONFERENCE, PROCEEDINGS, BOLS I - III SE PROCEEDINGS-FRONTIERS IN EDUCATION CONFERENCE LA English DT Proceedings Paper CT 27th Annual Conference on Frontiers in Education - Teaching and Learning in an Era of Change (FIE 97) CY NOV 05-08, 1997 CL PITTSBURGH, PA SP IEEE Educ Soc, IEEE Comp Soc, Amer Soc Engn Educ, Educ Res & Methods Div, Univ Pittsburgh RP Coleman, C (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0190-5848 BN 0-7803-4087-6 J9 PROC FRONT EDUC CONF PY 1997 BP 10 EP 10 PG 1 WC Education & Educational Research; Education, Scientific Disciplines SC Education & Educational Research GA BJ93M UT WOS:A1997BJ93M00004 ER PT B AU Zhu, DM Stout, JH Shores, DA AF Zhu, DM Stout, JH Shores, DA BE Shores, DA Rapp, RA Hou, PY TI Determination of stress gradients in oxidized Ni-Cr alloy substrates by in-situ X-ray diffraction SO FUNDAMENTAL ASPECTS OF HIGH TEMPERATURE CORROSION SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Symposium on Fundamental Aspects of High Temperature Corrosion, at the 190th Meeting of the Electrochemical-Society CY OCT 08-09, 1996 CL SAN ANTONIO, TX SP Electrochem Soc DE high temperature oxidation; strain gradient; concentration gradient; variable lattice parameter AB Stresses that develop in oxide scales and in the metal substrate during oxidation and subsequent heating/cooling cycles often cause scale cracking and spallation, a common mode of alloy degradation. To understand the origin and evolution of these stresses, one must have knowledge of their distributions, especially in the direction of the scale thickness. This paper reports on an experimental determination of strain gradients (stresses are inferred) in the substrate of oxidized Ni-30Cr and Ni-30Cr-0.5Y alloys by in-situ X-ray diffraction. The measurements must be corrected for the concentration gradient in the alloy substrate arising from chromium depletion. The variation of strain with depth is determined by the use of variable tilt angles of incident X-ray beam. Earlier work reported strain gradients in the oxide scales on these alloys. The results show that the stress gradients on these two alloys were different, possibly due to the segregation of yttrium in the scale near the metal/scale interface. RP Zhu, DM (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 10 S MAIN ST, PENNINGTON, NJ 08534-2896 BN 1-56677-126-9 J9 ELEC SOC S PY 1997 VL 96 IS 26 BP 41 EP 61 PG 21 WC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science GA BH09D UT WOS:A1997BH09D00004 ER PT B AU Ogbuji, LUJT Humphrey, DL AF Ogbuji, LUJT Humphrey, DL BE Shores, DA Rapp, RA Hou, PY TI Comparing the oxidation rates of SiC before and after oxide devitrification SO FUNDAMENTAL ASPECTS OF HIGH TEMPERATURE CORROSION SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Symposium on Fundamental Aspects of High Temperature Corrosion, at the 190th Meeting of the Electrochemical-Society CY OCT 08-09, 1996 CL SAN ANTONIO, TX SP Electrochem Soc AB The oxidation rate of SIC was measured before and after devitrification of the oxide, and compared to determine the effect of oxide crystallinity on the oxidation kinetics. For valid comparison, some stringent precautions had to be taken to ensure that no other significant factor in the oxidation. process had changed between the oxidation and reoxidation runs, apart from the state of the oxide. Those precautions are discussed here. RP Ogbuji, LUJT (reprint author), NASA,LEWIS RES CTR,NYMA SETAR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 10 S MAIN ST, PENNINGTON, NJ 08534-2896 BN 1-56677-126-9 J9 ELEC SOC S PY 1997 VL 96 IS 26 BP 163 EP 173 PG 11 WC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science GA BH09D UT WOS:A1997BH09D00013 ER PT B AU Zhu, DM Stout, JH Shores, DA AF Zhu, DM Stout, JH Shores, DA BE Shores, DA Rapp, RA Hou, PY TI Influence of yttrium on chromia scale growth on Ni-Cr alloys SO FUNDAMENTAL ASPECTS OF HIGH TEMPERATURE CORROSION SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Symposium on Fundamental Aspects of High Temperature Corrosion, at the 190th Meeting of the Electrochemical-Society CY OCT 08-09, 1996 CL SAN ANTONIO, TX SP Electrochem Soc DE reactive element effect; chemical potential gradient; defect structure; interface instability; stress effect AB The Cr2O3 scale formed on Ni-Cr alloys is generally regarded as growing by nearly exclusive cation diffusion. The scale exhibits two regions defined by their predominant defects: an inner region near the oxide/alloy interface where chromium interstitials predominate; and an outer region near the oxide/gas interface where chromium vacancies are predominant. The transport of these defects determines the oxidation mechanism and the scale growth rate. Since the total chemical potential gradient is a function of the stress gradient as well as the oxygen potential gradient, the oxidation stresses and distributions of stresses will affect the defect structure type and relative importance of anion transport as compared to cation transport. It is proposed that the total chemical potential gradient across the Cr2O3 scale in Ni-30Cr-0.5Y alloy establishes a steeper oxygen vacancy gradient and a less steep chromium interstitial gradient through the oxide scale as compared with that of the Ni-30Cr alloy, thereby enhancing oxygen anion inward diffusion along grain boundaries and reducing chromium cation outward diffusion. Therefore, the oxidation mechanism in the yttrium-containing alloy is no longer exclusive cation diffusion but includes a small, but important oxygen flux. It is also suggested that the enhanced oxygen inward diffusion is an important factor in the growth instability of the oxide/alloy interface commonly observed in yttrium-doped alloys. The convoluted metal/scale interface is often cited as an important factor in improving the scale's resistance to fracture and spallation. RP Zhu, DM (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 10 S MAIN ST, PENNINGTON, NJ 08534-2896 BN 1-56677-126-9 J9 ELEC SOC S PY 1997 VL 96 IS 26 BP 220 EP 240 PG 21 WC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science GA BH09D UT WOS:A1997BH09D00018 ER PT B AU Opila, EJ Jacobson, NS AF Opila, EJ Jacobson, NS BE Shores, DA Rapp, RA Hou, PY TI Volatile hydroxide species of common protective oxides and their role in high temperature corrosion SO FUNDAMENTAL ASPECTS OF HIGH TEMPERATURE CORROSION SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Symposium on Fundamental Aspects of High Temperature Corrosion, at the 190th Meeting of the Electrochemical-Society CY OCT 08-09, 1996 CL SAN ANTONIO, TX SP Electrochem Soc AB Thermodynamic data for volatile hydroxides and oxyhydroxides formed from the reaction of water vapor with Cr2O3, SiO2, Al2O3, Y2O3, and ZrO2 were assembled. The volatile species formed at temperatures between 800 and 2200K in model combustion environments containing 10% water vapor and 10% oxygen at 1 and 10 bar total pressure were calculated using free energy minimization techniques. Assuming an acceptable maximum vapor pressure limit for volatile species of 10(-6) bar, an upper use temperature for these oxides was determined at 1 and 10 bar total pressure. The dependence of these volatile species on both water vapor and oxygen pressure was determined. RP Opila, EJ (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 0 TC 14 Z9 14 U1 0 U2 3 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 10 S MAIN ST, PENNINGTON, NJ 08534-2896 BN 1-56677-126-9 J9 ELEC SOC S PY 1997 VL 96 IS 26 BP 269 EP 280 PG 12 WC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science GA BH09D UT WOS:A1997BH09D00021 ER PT B AU Zhu, DM Miller, RA AF Zhu, DM Miller, RA BE Shores, DA Rapp, RA Hou, PY TI Evaluation of oxidation damage in thermal barrier coating systems SO FUNDAMENTAL ASPECTS OF HIGH TEMPERATURE CORROSION SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Symposium on Fundamental Aspects of High Temperature Corrosion, at the 190th Meeting of the Electrochemical-Society CY OCT 08-09, 1996 CL SAN ANTONIO, TX SP Electrochem Soc AB A method based on the technique of dilatometry has been established to quantitatively evaluate the interfacial damage due to the oxidation in a thermal barrier coating system. Strain isolation and adhesion coefficients have been proposed to characterize the thermal barrier coating (TBC) performance based on its thermal expansion behavior. It has been found that, for a thermal barrier coating system consisting of ZrO2-8%Y2O3/FeCrAlY/4140 steel substrate, the oxidation of the bond coat and substrate significantly reduced the ceramic coating adherence, as inferred from the dilatometry measurements. The in-situ thermal expansion measurements under 30 degrees C to 700 degrees C thermal cycling in air showed that the adhesion coefficient, A(i), decreased by 25% during the first 35 oxidation cycles. Metallography showed that delamination occurred at both the ceramic/bond coat and bond coat/substrate interfaces. In addition, the strain isolation effect has been improved by increasing the FeCrAlY bond coat thickness. The strain isolation coefficient, S-i, increased from about 0.04 to 0.25, as the bond coat thickness changed from 0.1 mm to 1.0 mm. It may be possible to design optimum values of strain isolation and interface adhesion coefficients to achieve the best TBC performance. RP Zhu, DM (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 10 S MAIN ST, PENNINGTON, NJ 08534-2896 BN 1-56677-126-9 J9 ELEC SOC S PY 1997 VL 96 IS 26 BP 289 EP 307 PG 19 WC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Electrochemistry; Metallurgy & Metallurgical Engineering; Materials Science GA BH09D UT WOS:A1997BH09D00023 ER PT S AU Proffitt, CR AF Proffitt, CR BE Bedding, TR Booth, AJ Davis, J TI The importance of helium and metals diffusion in stars SO FUNDAMENTAL STELLAR PROPERTIES: THE INTERACTION BETWEEN OBSERVATION AND THEORY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 189th Symposium of the International-Astronomical-Union on Fundamental Stellar Properties - The Interaction Between Observation and Theory CY JAN 13-17, 1997 CL UNIV SYDNEY, WOMENS COLLEGE, SYDNEY, AUSTRALIA SP Int Astron Union HO UNIV SYDNEY, WOMENS COLLEGE ID PARTIALLY IONIZED-GASES; SOLAR MODELS; ELEMENT DIFFUSION; THERMAL-DIFFUSION; OSCILLATIONS; ABUNDANCE; INTERIOR; SUN AB Comparisons between models of the solar interior and sound speed profiles derived from inversions of helioseismic data have demonstrated that it is essential to include the effects of gravitational settling when calculating the structure and evolution of the Sun. Including settling should also be necessary for models of metal poor main-sequence stars and results in a substantial reduction in the ages derived for globular clusters. In many cases it is clear that competing hydrodynamic processes, such as mass loss or rotationally driven mixing, will limit the effectiveness of gravitational separation of chemical elements. However, the quantitative details and even the relative importance of the different processes in various types of stars remains poorly understood. C1 CATHOLIC UNIV AMER, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP Proffitt, CR (reprint author), COMP SCI CORP, CODE 680, GREENBELT, MD 20771 USA. NR 31 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4651-3 J9 IAU SYMP PY 1997 IS 189 BP 355 EP 360 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ51R UT WOS:A1997BJ51R00047 ER PT J AU Lewis, JS AF Lewis, JS TI Escaping the ultimate disaster - A cosmic collision SO FUTURIST LA English DT Article RP Lewis, JS (reprint author), UNIV ARIZONA,LUNAR & PLANETARY LAB,NASA,ARIZONA SPACE ENGN RES CTR,TUCSON,AZ 85721, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD FUTURE SOCIETY PI BETHESDA PA 7910 WOODMONT AVE, SUITE 450, BETHESDA, MD 20814 SN 0016-3317 J9 FUTURIST JI Futurist PD JAN-FEB PY 1997 VL 31 IS 1 BP 16 EP 19 PG 4 WC Social Issues SC Social Issues GA WE851 UT WOS:A1997WE85100011 ER PT S AU Kim, M Fujiwara, BH Humphrey, DA Martin, SC Smith, RP Siegel, PH AF Kim, M Fujiwara, BH Humphrey, DA Martin, SC Smith, RP Siegel, PH GP IEEE TI A 600 GHz planar frequency multiplier feed on a silicon dielectric-filled parabola SO GAAS IC SYMPOSIUM - 19TH ANNUAL, TECHNICAL DIGEST 1997 SE TECHNICAL DIGEST - IEEE GALLIUM ARSENIDE INTEGRATED CIRCUIT SYMPOSIUM LA English DT Proceedings Paper CT 19th Annual IEEE Gallium Arsenide Integrated Circuit (GaAs IC) Symposium CY OCT 12-15, 1997 CL ANAHEIM, CA SP IEEE Electron Devices Soc, IEEE Microwave Theory & Tech Soc AB A novel all-planar quasi-optical schottky varactor diode frequency doubler has been fabricated and has produced more than 1 mW of output power at 600 GHz with an approximately 2 percent conversion efficiency. This simple-to-assemble all-planar diode multiplier could replace complicated waveguide blocks commonly used at submillimeter-wave frequencies to provide local oscillator power for terahertz receiver components. RP Kim, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 168-314,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1064-7775 BN 0-7803-4084-1 J9 TG IEEE GAL ARS PY 1997 BP 287 EP 290 DI 10.1109/GAAS.1997.628288 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ80G UT WOS:A1997BJ80G00064 ER PT B AU Loewenstein, M AF Loewenstein, M BE Soker, N TI Cooling flows in elliptical galaxies SO GALACTIC AND CLUSTER COOLING FLOWS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Galactic and Cluster Cooling Flows CY AUG 05-08, 1996 CL UNIV HAIFA, ORANIM, ISRAEL HO UNIV HAIFA AB Cooling flows in elliptical galaxies are reviewed with an emphasis on recent x-ray results and a comparison with the phenomenon as manifest in clusters of galaxies. There is now strong, though indirect, evidence far both inflow and cooling in the hot ISM in elliptical galaxies. The search for signatures of catastrophic cooling such as excess absorption, central surface brightness excesses, and multiple temperatures has begun, but strong evidence for these has yet to be uncovered. A notable exception is the ASCA detection of at least two temperature components in the center of NGC 4636 which I have recently confirmed and present here. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RP Loewenstein, M (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20770 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-35-X J9 ASTR SOC P PY 1997 VL 115 BP 100 EP 108 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK79W UT WOS:000073437600013 ER PT S AU Beye, R George, T AF Beye, R George, T BE Abernathy, CR Amano, H Zolper, JC TI A chemical and structural study of the AlN-Si interface SO GALLIUM NITRIDE AND RELATED MATERIALS II SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Gallium Nitride and Related Materials II CY APR 01-04, 1997 CL SAN FRANCISCO, CA SP Mat Res Soc AB Samples of AlN grown on silicon [111] substrates were examined using electron energy loss spectroscopy (EELS) and selected area diffraction (SAD) with high-resolution transmission electron microscopy (TEM) to determine the source of out-of-plane tilts and in-plane rotations of the AlN crystallites at the Si interface. SAD results indicate that the interfacial crystallites are sheared along vertical planes, with random, intercrystalline rotation. The interfacial phenomena are believed to be the result of Si-Al-N interaction. Analytical experiments show no evidence of silicon nitride formation, witnessed by nitrogen-K peak shape, up to the Si interface. No evidence of substrate-epilayer interdiffusion was observed. Chemical interaction within one monolayer of the interface is therefore suspected as the cause of the epilayer tilts and rotations. RP Beye, R (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-372-X J9 MATER RES SOC SYMP P PY 1997 VL 468 BP 269 EP 274 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BJ46Q UT WOS:A1997BJ46Q00043 ER PT J AU Krot, AN Zolensky, ME Wasson, JT Scott, ERD Keil, K Ohsumi, K AF Krot, AN Zolensky, ME Wasson, JT Scott, ERD Keil, K Ohsumi, K TI Carbide-magnetite assemblages in type-3 ordinary chondrites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID FISCHER-TROPSCH SYNTHESIS; INTERPLANETARY DUST; SEMARKONA; METEORITE; ORIGINS; SOLAR; FE AB Abundant carbide-magnetite assemblages occur in matrix, chondrules, and chondrule rims in several H3, L3, and LL3 chondrites. Carbides, cohenite ((Fe,Ni)(3)C), and haxonite ((Fe,Ni)(23)C-6) show compositional variations between different meteorites and appreciable ranges within meteorites. Carbides in H chondrites have lower Co contents (0-0.6 wt%) than those in L and LL chondrites (0.3-1.2 wt%). Metal associated with carbides and magnetite consists of high-Ni (50-70 wt%) taenite and, in L and LL chondrites, Co-rich (up to 35 wt%) kamacite; minor element contents of troilite and magnetite are very low. Textural observations indicate that carbide-magnetite assemblages formed by replacement of metal-sulfide nodules. The high Co contents of residual kamacite in association with carbides indicates that Co is not incorporated into carbides (i.e., Fe/Co is much higher in the carbides than in kamacite). Because Ni in carbides and magnetite is low, the Ni contents of residual taenite tend to be high. Ni-rich sulfides were found only in LL3 chondrites, possibly indicating their more extensive oxidation and/or aqueous alteration. We suggest that carbide-magnetite assemblages in type-3 ordinary chondrites formed as the result of hydrothermal alteration of metallic Fe in metal-troilite nodules by a C-O-H-bearing fluid on their parent bodies. This alteration resulted in carbidization of Fe-Ni metal, probably by CO gas (e.g., 15 Fe(s) + 4 CO(g) = Fe-3(s) + Fe3O4(s) or 3 Fe(s) + 2 CO(g) = Fe3C(s), CO2(g)), and oxidation, probably by H2O gas (e.g., 3Fe(s) + 4H(2)O(g) = Fe3O4(s) + 4H(2)(g)). The C-O-H-bearing fluids, which were possibly released during metamorphism and transported through zones of high permeability, may have been derived from ices, adsorbed gases, or hydrated minerals. The CO may be the result of the reaction of carbon compounds (e.g., hydrocarbons) with water vapor or magnetite. Copyright (C) 1997 Elsevier Science Ltd C1 UNIV HAWAII MANOA,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822. NASA,LYNDON B JOHNSON SPACE CTR,EARTH SCI & SOLAR SYST EXPLORAT DIV,HOUSTON,TX 77058. NATL INST HIGH ENERGY PHYS,PHOTON FACTORY,TSUKUBA,IBARAKI,JAPAN. RP Krot, AN (reprint author), UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90095, USA. OI Wasson, John/0000-0002-7253-2300 NR 34 TC 62 Z9 62 U1 1 U2 12 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 JAN PY 1997 VL 61 IS 1 BP 219 EP 237 DI 10.1016/S0016-7037(96)00336-5 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WE861 UT WOS:A1997WE86100015 ER PT J AU Mittlefehldt, DW Lindstrom, MM AF Mittlefehldt, DW Lindstrom, MM TI Magnesian basalt clasts from the EET 92014 and Kapoeta howardites and a discussion of alleged primary magnesian HED basalts SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PARENT BODY; MESOSIDERITES; CHONDRITES; EUCRITES; ORIGIN; PETROGENESIS; DIOGENITES AB We have performed petrologic and geochemical studies on pyroxene-phyric, magnesian basalt clasts from the howardites EET 92014 and Kapoeta. Pyroxenes in the EET 92014 clast are strongly zoned from Wo(4.5)En(68.9)Fs(26.6) cores to Wo(22.2)En(18.5)Fs(59.2) rims. The pyroxene has also suffered later FeO metasomatism along healed fractures that has resulted in compositions with atypically high FeO/MnO ratios. Metasomatized pyroxenes reach compositions as ferroan as Wo(3.2)En(37.0)Fs(59.8). Pyroxenes in the Kapoeta clast have cores that are more magnesian, Wo(1.8)En(80.2)Fs(18.0), and are less strongly zoned, to Wo(3.6)En(51.0)Fs(45.4). Atypically high FeO/MnO in the most ferroan pyroxenes in this clast coupled with late ferroan olivine (up to similar to Fa(64)), reflect late-stage addition of FeO to the melt rather than igneous fractionation. The EET 92014 clast is enriched in the refractory incompatible lithophile elements and shows a refractory lithophile element pattern similar to Stannern and Bouvante. The clast is enriched in Cr2O3 and MgO and depleted in Al2O3 and CaO compared to main group or Stannern trend eucrites. Based on bulk major and trace lithophile element composition, this pyroxene-phyric clast cannot be directly related to basaltic eucrites. This clast is either an impact melt of a trace element-rich, polymict eucrite or howardite target, or a primary melt of a more magnesian source region than that which produced basaltic eucrites. We favor the former interpretation. Low siderophile element abundances, within the ranges for monomict eucrites, indicate <0.5% chondritic contamination in the clast, however. The Kapoeta clast has a major element composition within the range of howardites and likely is an impact melt of such a target lithology. Comparison with other reported magnesian basalt clasts from howardites indicates that in all likelihood, all heretofore alleged primary magnesian basalt clasts are impact melts of polymict targets. Two magnesian eucrites, ALHA81001 and Pomozdino, and magnesian eucrite clasts from the polymict eucrite Petersburg may possibly be primary melts of a magnesian source region not directly related to basaltic eucrites. Copyright (C) 1997 Elsevier Science Ltd. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP Mittlefehldt, DW (reprint author), LOCKHEED MARTIN ENGN & SCI SERV,C23,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 35 TC 20 Z9 21 U1 0 U2 0 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 JAN PY 1997 VL 61 IS 2 BP 453 EP 462 DI 10.1016/S0016-7037(96)00357-2 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WG851 UT WOS:A1997WG85100016 ER PT J AU Becker, L Glavin, DP Bada, JL AF Becker, L Glavin, DP Bada, JL TI Polycyclic aromatic hydrocarbons (PAHs) in Antarctic Martian meteorites, carbonaceous chondrites, and polar ice SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Letter ID SNC METEORITES; ISOTOPIC COMPOSITION; WEATHERING PRODUCTS; ALH 84001; MARS; EETA-79001; GREENLAND; NITROGEN; ALH84001; OXYGEN AB Recent analyses of the carbonate globules present in the Martian meteorite ALH84001 have detected polycyclic aromatic hydrocarbons (PAHs) at the ppm level (McKay et al., 1996). The distribution of PAHs observed in ALH84001 was interpreted as being inconsistent with a terrestrial origin and were claimed to be indigenous to the meteorite, perhaps derived from an ancient martian biota. We have examined PAHs in the Antarctic shergottite EETA79001, which is also considered to be from Mars, as well as several Antarctic carbonaceous chondrites. We have found that many of the same PAHs detected in the ALH84001 carbonate globules are present in Antarctic carbonaceous chondrites and in both the matrix and carbonate (druse) component of EETA79001. We also investigated PAHs in polar ice and found that carbonate is an effective scavenger of PAHs in ice meltwater. Moreover, the distribution of PAHs in the carbonate extract of Antarctic Allan Hills ice is remarkably similar to that found in both EETA79001 and ALH84001. The reported presence of L-amino acids of apparent terrestrial origin in the EETA79001 druse material (McDonald and Bada, 1995) suggests that this meteorite is contaminated with terrestrial organics probably derived from Antarctic ice meltwater that had percolated through the meteorite. Our data suggests that the PAHs observed in both ALH84001 and EETA79001 are derived from either the exogenous delivery of organics to Mars or extraterrestrial and terrestrial PAHs present in the ice meltwater or, more likely, from a mixture of these sources. It would appear that PAHs are not useful biomarkers in the search for extinct or extant life on Mars. Copyright (C) 1997 Elsevier Science Ltd. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RP Becker, L (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA. RI Glavin, Daniel/D-6194-2012 OI Glavin, Daniel/0000-0001-7779-7765 FU NCCDPHP CDC HHS [DPP91-18494] NR 33 TC 73 Z9 74 U1 0 U2 14 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 JAN PY 1997 VL 61 IS 2 BP 475 EP 481 DI 10.1016/S0016-7037(96)00400-0 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WG851 UT WOS:A1997WG85100018 PM 11541466 ER PT J AU Andreev, AA Nikolaev, VI Boi'sheiyanov, DY Petrov, VN AF Andreev, AA Nikolaev, VI Boi'sheiyanov, DY Petrov, VN TI Pollen and isotope investigations of an ice core from Vavilov Ice Cap, October Revolution Island, Severnaya Zemlya Archipelago, Russia SO GEOGRAPHIE PHYSIQUE ET QUATERNAIRE LA French DT Article ID CANADA; SHEET AB The Vavilov Ice Cap (79 degrees 27'N, 95 degrees 21'E) was cored during February and March of 1988. The corer passed through 457.18m of glacier ice, 2.15 m of moraine-containing ice, and 2.28 m of underlying rocks. Structural-stratigraphical and isotope analysis show the glacier ice is of Holocene in age; the ice layer covered by frozen deposits is Pleistocene glacier ice; and the ground (ice wedge?) ice from underlying sediments was formed during the Last Interglacial. Palynological studies of this core, carried out for the first time in the Russian Arctic demonstrate that the pollen spectra have a unique pattern. It reduces the possibility of correlation between the Vavilov Ice Cape spectra and pollen spectra from other surficial deposits, because the ice retains pollen and spores brought from enormous distances. Only the upper 65 m of the core is easily dated, to the last millennium, by the presence of cereals, Plantago lanceolata, Centaurea cyanus, Cannabis pollen. That is in good agreement with the model of age distribution based upon depth. The presence of considerable amounts of Tilia cordifolia pollen, a West-European species in the upper layers suggests that summer air masses have been dominantly from the southwest during the last 500 years. The pollen data do not contradict the conclusion the Vavilov ice core is composed of a section of Holocene ice, moraine-containing ice representing the Pleistocene episode, and a ground ice formed during an earlier warm period (Last Interglacial?). C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Andreev, AA (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Andreev, Andrei/J-2701-2015 NR 54 TC 18 Z9 20 U1 0 U2 4 PU PRESSES UNIV MONTREAL PI MONTREAL PA PO BOX 6128, SUCCURSALE A, MONTREAL, QUEBEC H3C 3J7, CANADA SN 0705-7199 J9 GEOGR PHYS QUATERN JI Geogr. Phys. Quat. PY 1997 VL 51 IS 3 BP 379 EP 389 PG 11 WC Geography, Physical; Paleontology SC Physical Geography; Paleontology GA YP297 UT WOS:000071262800015 ER PT S AU DesMarais, DJ AF DesMarais, DJ BE Banfield, JF Nealson, KH TI Long-term evolution of the biogeochemical carbon cycle SO GEOMICROBIOLOGY: INTERACTIONS BETWEEN MICROBES AND MINERALS SE REVIEWS IN MINERALOGY LA English DT Review CT Short Course on Geomicrobiology CY OCT 18-19, 1997 CL ALTA, UT SP Mineral Soc Amer ID EARTHS EARLY ATMOSPHERE; WESTERN-AUSTRALIA; SURFACE TEMPERATURES; CONTINENTAL-CRUST; PHANEROZOIC TIME; ORGANIC-CARBON; PILBARA BLOCK; BILLION YEARS; SOUTH-AFRICA; OXYGEN RP NASA, AMES RES CTR, DIV SPACE SCI, MOFFETT FIELD, CA 94035 USA. NR 100 TC 19 Z9 19 U1 1 U2 4 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 0275-0279 BN 0-939950-45-6 J9 REV MINERAL JI Rev. Mineral. PY 1997 VL 35 BP 429 EP 448 PG 20 WC Mineralogy SC Mineralogy GA BJ74J UT WOS:A1997BJ74J00013 ER PT J AU Wu, XP Wahr, JM AF Wu, XP Wahr, JM TI Effects of non-hydrostatic core-mantle boundary topography and core dynamics on Earth rotation SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE core-mantle boundary; Earth's rotation; nutation ID PKP TRAVEL-TIMES; FORCED NUTATIONS; INNER CORE; TIDE OBSERVATIONS; OCEANLESS EARTH; INTERFEROMETRY; WOBBLE AB VLBI estimates for the retrograde annual nutation have shown that there is a 2 mas discrepancy with model results that assume a hydrostatically pre-stressed earth. This discrepancy has been used to infer that the non-hydrostatic Y-2(O) component of core-mantle-boundary (CMB) topography is roughly 0.5 km in amplitude. However, the possible effects of other topographic components have not been fully examined. Based on an earth model with a rigid mantle, a homogeneous and incompressible fluid core, and a slightly non-hydrostatic core-mantle boundary, we investigate effects of the core and of non-hydrostatic CMB topography on the Earth's nutations, Chandler wobble and tidal changes of the length of day (LOD). A convergent numerical technique is developed to solve the differential and boundary equations for both the free and forced motions. fn our solution, the fluid pressure is represented by a truncated sum of spherical harmonic functions in a special set of coordinates. We retain second-order CMB topographic factors with the equatorial core rotation in our nutation calculations. Using the degree variances of a recent seismically inferred CMB model (with nonhydrostatic CMB topography of about 3.5 km rms), the rms contribution of the randomly generated non-Y-2(O) topographic components to the retrograde annual nutation is about 0.55 mas. However, the effects of CMB topography depend on the reference earth model. A simple analysis shows that nutational effects for a realistic earth, with a non-rigid mantle and realistically stratified core, can be inferred by dividing our results by a factor of 2.61. The transformation then gives an rms effect of about 0.2 mas on the retrograde annual nutation. The effects depend on some CMB components more than they do on others. For example, results as large as 0.77 mas in the retrograde annual amplitude are possible for a realistic earth due to certain individual non-Y-2(O) CMB topographic components with mean-to-peak amplitudes of 4-5 km. The effects grow quadratically with topography, so that a 2 mas nutation amplitude would require those components to be 6-7 km in amplitude. The CMB topography is poorly known at present, but components of such magnitude may be unlikely. For the Chandler wobble and the tidal variations of LOD, the effects of CMB topography are likely to be small. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP Wu, XP (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 238-600,PASADENA,CA 91125, USA. NR 27 TC 14 Z9 14 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD JAN PY 1997 VL 128 IS 1 BP 18 EP 42 DI 10.1111/j.1365-246X.1997.tb04069.x PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WC166 UT WOS:A1997WC16600003 ER PT J AU Newell, RE Zhu, Y Read, WG Waters, JW AF Newell, RE Zhu, Y Read, WG Waters, JW TI Relationship between tropical upper tropospheric moisture and eastern tropical Pacific sea surface temperature at seasonal and interannual time scales SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN AB Water vapor in the tropical upper troposphere, above the altitudes ordinarily sampled by radiosonde humidity elements, is important in controlling atmospheric infrared energy loss to space, both by its dominance of infrared transmission and its role in cloud formation. Much of the water vapor arrives in the upper troposphere above about 12 km in plumes associated with cumulonimbus complexes; values at 215 and 147 hPa have recently been estimated from the Microwave Limb Sounder on the NASA Upper Atmosphere Research Satellite. In equatorial regions, time changes of upper troposphere moisture over a three year period, 1991-1994, are closely related to sea surface temperature changes in the eastern tropical Pacific, including seasonal and nonseasonal variations. Maps of the annual and semi-annual components at 215 and 147 hPa show maxima over the eastern hemisphere land masses and the maritime continent, as well as over Central and South America. C1 CALTECH,JET PROP LAB,PASADENA,CA. RP Newell, RE (reprint author), MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. NR 20 TC 19 Z9 19 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 JAN 1 PY 1997 VL 24 IS 1 BP 25 EP 28 DI 10.1029/96GL03776 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WB786 UT WOS:A1997WB78600007 ER PT J AU Schoeberl, MR Roche, AE Russell, JM Ortland, D Hays, PB Waters, JW AF Schoeberl, MR Roche, AE Russell, JM Ortland, D Hays, PB Waters, JW TI An estimation of the dynamical isolation of the tropical lower stratosphere using UARS wind and trace gas observations of the quasibiennial oscillation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DIABATIC CIRCULATION; MODEL AB Upper Atmosphere Research Satellite tropical wind and constituent measurements are used to estimate an upper limit of mid-latitude to tropical trace gas exchange by examining the phase of the N2O/CH4 ratio with respect to the Quasi-Biennial Oscillation winds. Assuming a simple diffusive model for tropical - mid-latitude exchange in the 20-28 km region, the mixing times are estimated to be at least 18 months, and, we estimate an eddy mixing coefficient of 7 x 10(8) cm(2)/sec. This low mixing rate suggests that if significant chemical mixing into the lower tropical stratosphere occurs, as has been suggested by observational data, then this mixing must take place below 20 km. C1 LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV MICHIGAN,ANN ARBOR,MI 48109. CALTECH,JET PROP LAB,PASADENA,CA. RP Schoeberl, MR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 910,GREENBELT,MD 20771, USA. NR 24 TC 30 Z9 31 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 JAN 1 PY 1997 VL 24 IS 1 BP 53 EP 56 DI 10.1029/96GL03370 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WB786 UT WOS:A1997WB78600014 ER PT J AU Dwyer, JR Mason, GM Mazur, JE vonRosenvinge, TT AF Dwyer, JR Mason, GM Mazur, JE vonRosenvinge, TT TI Acceleration of solar flare He-3 at the Earth's bow shock SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ENERGETIC PARTICLES; EVENTS; WIND; IONS; TRANSPORT; UPSTREAM AB The STEP instrument on the WIND spacecraft observed several upstream events in coincidence with He-3 and Fe-rich solar energetic particle events in late 1994. The distinctive ion composition of the impulsive solar energetic particle population provides an opportunity to study mechanisms that produce upstream events. We report energy spectra and mass composition of both the upstream event ions and SEP ions as well as the first detection of He-3 ions in an upstream event. The detection of He-3 unambiguously demonstrates that salar energetic particles can undergo further acceleration near the Earth. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Dwyer, JR (reprint author), UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742, USA. NR 25 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 JAN 1 PY 1997 VL 24 IS 1 BP 61 EP 64 DI 10.1029/96GL03660 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WB786 UT WOS:A1997WB78600016 ER PT J AU Hanisco, TF Wennberg, PO Cohen, RC Anderson, JG Fahey, DW Keim, ER Gao, RS Wamsley, RC Donnelly, SG DelNegro, LA Salawitch, RJ Kelly, KK Proffitt, MH AF Hanisco, TF Wennberg, PO Cohen, RC Anderson, JG Fahey, DW Keim, ER Gao, RS Wamsley, RC Donnelly, SG DelNegro, LA Salawitch, RJ Kelly, KK Proffitt, MH TI The role of HOx in super- and subsonic aircraft exhaust plumes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER STRATOSPHERE; RADICALS; EMISSION AB The generation of sulfuric acid aerosols in aircraft exhaust has emerged as a critical issue in determining the impact of supersonic aircraft on stratospheric ozone. It has long been held that the first step in the mechanism of aerosol formation is the oxidation of SO2 emitted from the engine by OH in the exhaust plume. We report in situ measurements of OH and HO2 in the exhaust plumes of a supersonic (Air France Concorde) and a subsonic (NASA ER-2) aircraft in the lower stratosphere. These measurements imply that reactions with OH are responsible for oxidizing only a small fraction of SO2 (2%), and thus cannot explain the large number of particles observed in the exhaust wake of the Concorde. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP Hanisco, TF (reprint author), HARVARD UNIV, DEPT CHEM, 12 OXFORD ST, CAMBRIDGE, MA 02138 USA. RI Salawitch, Ross/B-4605-2009; Cohen, Ronald/A-8842-2011; Wennberg, Paul/A-5460-2012; Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013 OI Salawitch, Ross/0000-0001-8597-5832; Cohen, Ronald/0000-0001-6617-7691; Fahey, David/0000-0003-1720-0634 NR 17 TC 19 Z9 19 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 1997 VL 24 IS 1 BP 65 EP 68 DI 10.1029/96GL03724 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WB786 UT WOS:A1997WB78600017 ER PT J AU Woo, R AF Woo, R TI Evidence for the reversal of magnetic field polarity in coronal streamers SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND; FLUCTUATIONS; PLASMA; SHEET; 1-AU AB Faraday rotation observations are unique amongst radio occultation measurements in that they respond to magnetic field in addition to electron density, making it possible to probe the coronal magnetic field. Signatures interpreted as transients in Faraday rotation measurements made by Pioneer 6 in 1968 in the heliocentric distance range of 6-11 R(O) are shown to be caused by coronal streamer stalks of angular size 1-2 degrees observed in white-light measurements rather than the magnetic bottles interpreted earlier. This identification makes available the first magnetic field observations of coronal streamers. The detection of the reversal of magnetic field polarity high in the corona provides observational evidence confirming what has previously only been inferred from modeling - that streamers observed in white-light measurements are the manifestation of the heliospheric current sheet. These results reinforce the apparent connection between the coronal streamer stalk observed in white-light coronagraphs and the heliospheric plasma sheet identified by in situ fields and particles measurements beyond 0.3 AU. RP Woo, R (reprint author), CALTECH,JET PROP LAB,MS 238-725,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 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 JAN 1 PY 1997 VL 24 IS 1 BP 97 EP 100 DI 10.1029/96GL03479 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WB786 UT WOS:A1997WB78600025 ER PT S AU Pennoyer, S AF Pennoyer, S BE Pikitch, EK Huppert, DD Sissenwine, MP TI Bycatch management in Alaska groundfish fisheries SO GLOBAL TRENDS: FISHERIES MANAGEMENT SE AMERICAN FISHERIES SOCIETY SYMPOSIUM SERIES LA English DT Proceedings Paper CT Symposium on Global Trends - Fisheries Management CY JUN 14-16, 1994 CL UNIV WASHINGTON, SEATTLE, WA SP Natl Marine Fisheries Serv, Univ Washington Coll Ocean & Fishery Sci, Wards Cove Packing Co, Ocean Trawl Inc HO UNIV WASHINGTON AB The history of the Alaska groundfish fisheries is reviewed with emphasis on the rapid evolution of the domestic fishery and its management based on experience gained through observation and management of the foreign groundfish fisheries since the early 1960s. The stable status of the Alaska groundfish resource is attributed largely to historical and ongoing efforts to collect information on resource status and inseason groundfish harvests, and closure of fisheries when annual quotas are reached. Nonselective harvesting techniques used in the groundfish fisheries result in incidental catches (bycatch) of nontarget species, size categories, or sex. An open-access management of the Alaska groundfish fisheries contributes to bycatch amounts that are greater than what is minimally needed to conduct the groundfish fisheries. Similarly, efforts to control bycatch are hampered by the intense competition for Alaska groundfish resources that result from overcapitalization of the domestic groundfish fleet and increasingly short fishing seasons. The effectiveness of numerous measures implemented to address the bycatch problem is reviewed, and a discussion of future approaches bring considered for effective bycatch management is presented. RP Pennoyer, S (reprint author), NATL MARINE FISHERIES SERV,ALASKA REG,POB 21668,JUNEAU,AK 99802, USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE, STE 110, BETHESDA, MD 20814-2199 SN 0892-2284 BN 1-888569-03-4 J9 AM FISH S S PY 1997 VL 20 BP 141 EP 150 PG 10 WC Fisheries SC Fisheries GA BJ91M UT WOS:A1997BJ91M00014 ER PT B AU Ivancic, WD Bobinsky, EA AF Ivancic, WD Bobinsky, EA GP IEEE TI ATM quality of service parameters at 45 Mbps using a satellite emulator: Laboratory measurements SO GLOBECOM 97 - IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, CONFERENCE RECORD, VOLS 1-3 LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 97) CY NOV 03-08, 1997 CL PHOENIX, AZ SP IEEE AB Results of 45-Mbps DS3 intermediate-frequency loopback measurements of asynchronous transfer mode (ATM) quality of service parameters (cell error ratio and cell loss ratio) are presented. These tests, which were conducted at the NASA Lewis Research Center in support of satellite-ATM interoperability research, represent initial efforts to quantify the minimum parameters for stringent ATM applications, such as MPEG-1 and MPEG-2 video transmission. Portions of these results were originally presented to the International Telecommunications Union's ITU-R Working Party 4B in February 1996 in support of their Draft Preliminary Recommendation on the Transmission of ATM Traffic via Satellite. RP Ivancic, WD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4199-6 J9 GLOB TELECOMM CONF PY 1997 BP 1129 EP 1132 PG 4 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BJ90L UT WOS:A1997BJ90L00214 ER PT B AU Weisskopf, MC ODell, SL AF Weisskopf, MC ODell, SL BE Hoover, RB Walker, ABC TI Calibration of the AXAF observatory: Overview SO GRAZING INCIDENCE AND MULTILAYER X-RAY OPTICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Grazing Incidence and Multilayer X-ray Optical Systems CY JUL 27-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE x rays; calibration; grazing-incidence optics; gratings; detectors; x-ray imaging; x-ray spectroscopy AB The Advanced X-ray Astrophysics Facility (AXAF) will soon begin its exploration of the x-fay universe, providing unprecedented angular and spectral resolution. Also unprecedented is the ambitious goal of calibrating the AXAF observatory to an accuracy of a few percent. Toward this end, AXAF science and engineering teams undertook an extensive calibration program at component, subsystem, and system levels. This paper is an overview of the system-level calibration activities, conducted over the past year at the Marshall Space Flight Center (MSFC) X-Ta,ay Calibration Facility (XRCF). C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP ODell, SL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES84,HUNTSVILLE,AL 35812, USA. OI O'Dell, Stephen/0000-0002-1868-8056 NR 0 TC 38 Z9 38 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2535-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3113 BP 2 EP 17 DI 10.1117/12.278838 PG 16 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BJ31L UT WOS:A1997BJ31L00001 ER PT B AU Kolodziejczak, JJ Austin, RA Elsner, RF ODell, SL Sulkanen, ME Swartz, DA Tennant, AF Weisskopf, MC Zirnstein, G McDermott, WC AF Kolodziejczak, JJ Austin, RA Elsner, RF ODell, SL Sulkanen, ME Swartz, DA Tennant, AF Weisskopf, MC Zirnstein, G McDermott, WC BE Hoover, RB Walker, ABC TI Uses of continuum radiation in the AXAF calibration SO GRAZING INCIDENCE AND MULTILAYER X-RAY OPTICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Grazing Incidence and Multilayer X-ray Optical Systems CY JUL 27-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE x rays; calibration; x-ray sources; grazing-incidence optics; detectors AB X-ray calibration of the Advanced X-ray Astrophysics Facility (AXAF) observatory at the MSFC X-Ray Calibration Facility (XRCF) made novel use of the x-ray continuum from a conventional electron-impact source. Taking advantage of the good spectral resolution of solid-state detectors, continuum measurements proved advantageous in calibrating the effective area of AXAF's High-Resolution Mirror Assembly (HRMA) and in verifying its alignment to the XRCF's optical axis. C1 USRA,MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP ODell, SL (reprint author), USRA,MARSHALL SPACE FLIGHT CTR,ES84,HUNTSVILLE,AL 35812, USA. OI O'Dell, Stephen/0000-0002-1868-8056 NR 0 TC 6 Z9 6 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2535-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3113 BP 65 EP 76 DI 10.1117/12.278889 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BJ31L UT WOS:A1997BJ31L00006 ER PT B AU Serlemitsos, PJ Ogasaka, Y Soong, Y Chan, KW AF Serlemitsos, PJ Ogasaka, Y Soong, Y Chan, KW BE Hoover, RB Walker, ABC TI The multilayer option for conical foil X-ray mirrors SO GRAZING INCIDENCE AND MULTILAYER X-RAY OPTICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Grazing Incidence and Multilayer X-ray Optical Systems CY JUL 27-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE X-rays; multilayers; foil mirrors; mirror design AB Multilayers used at grazing incidence offer likely the only real opportunity for extending imaging techniques in X-ray astronomy to tens of keV, or well beyond the usual upper bound when using single material reflecting surfaces. There are several reasons why conical foils are particularly suited for multilayer applications. For one thing, many of the arguments made in the past in favor of foil reflectors still hold, since multilayers do not eliminate the need elf extreme oblique incidence. Pie will show, additionally, that foil reflectors offer other important advantages which are likely to be essential toward the realization of wide band X-ray mirrors. Successful multilayer depositions on segments of our epoxy replicated foil reflectors have already been reported. In this paper we will review our own efforts at multilayer deposition on replicated surface fails, addressing in detail such relevant issues as consistency, quality and uniformity of the deposits, boundary roughness and potential, stress-induced foil shape distortions. Finally, we will present detailed mirror design and modeling aimed at future wide-band astronomical research. RP Serlemitsos, PJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2535-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3113 BP 244 EP 252 DI 10.1117/12.278853 PG 9 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BJ31L UT WOS:A1997BJ31L00021 ER PT S AU Kia, T Mellstrom, J Klumpp, A Munson, T Vaze, P AF Kia, T Mellstrom, J Klumpp, A Munson, T Vaze, P BE Culp, RD Wiens, SB TI TOPEX/POSEIDON autonomous maneuver experiment (TAME) design and implementation SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The need for higher level of spacecraft autonomy is gaining increased importance in future space missions planning. Future space missions will continue to be scientifically and technically more ambitious, and will demand more autonomy to accomplish complex tasks in uncertain environments and in close proximity to terrestrial bodies. In addition to mission demands, affordability is now a primary driver. The call is for smaller missions with greatly reduced ground control and operation. Spacecraft with highly autonomous, goal directed control systems would be required to meet these challenges. It is believed the autonomy in addition to reducing the mission operations cost. will enable science objectives not possible using the current spacecraft architectural designs. Autonomous maneuver planning and implementation is one the key candidate technologies identified for such missions. This paper describes the design and the implementation of an autonomous maneuver experiment. The experiment will provide proof of concept technology for an important area of on-board autonomy. TOPEX/POSEIDON Autonomous Maneuver Experiment (TAME) will provide the necessary algorithm for autonomous planning of constraint free attitude maneuvers to execute an Orbital Maintenance Maneuver (OMM). Currently the experiment is scheduled for June 1997. This paper will describe TAME's architecture, its planner algorithm and the design of the software. RP Kia, T (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 41 EP 56 PG 16 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00003 ER PT S AU Ketchum, EA Flatley, TW Morrissey, JR AF Ketchum, EA Flatley, TW Morrissey, JR BE Culp, RD Wiens, SB TI Application and flight data test results of an earth albedo model SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB Solar radiation at the earth's surface is at least partially reflected, This earth shine, or albedo, can be mistakenly sensed by a silicon solar cell found in coarse sun sensors commonly used for attitude determination resulting in skewed or erroneous measurements of the sun position, A mathematical model for simulating the coarse sun sensor output due to radiation originating from the visible sunlit portion of the earth was presented by Flatley and Moore, This paper discusses the validation of this model with flight data from the Rossi Xray Timing Explorer (RXTE) as well as the model's subsequent application to the Spartan 207 mission. Spartan 207 is a pre-programmed spacecraft with no RF command link that is deployed by the orbiter's Remote Manipulator System (RMS), Spartan 207 carried the Inflatable Antenna Experiment (IAE), a 50 ft. diameter inflatable structure mounted on 100 ft. long inflatable struts. After release from the RMS, the antenna was set to inflate after a timer was triggered when the Spartan Intermediate Sun Sensor (SISS) acquired the sun. This was done to insure that the antenna would not be mistakenly inflated inside the orbiter payload bay if the system was released then regrappled, or for some reason was still close to the orbiter, The analysis presented in this paper describes how the albedo model was used to set thresholds for the SISS to ensure that the earth albedo could not trigger an in bay release of the Spartan 207 IAE. RP Ketchum, EA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SPECIAL PAYLOADS DIV,CODE 745,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 79 EP 92 PG 14 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00005 ER PT S AU Gagosian, JS Furber, RD Malek, SC AF Gagosian, JS Furber, RD Malek, SC BE Culp, RD Wiens, SB TI Tracking and data relay satellites H, I, J compliance with NASA's orbital debris policy: A case study SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB Hughes Space and Communications (HSC) and NASA engineers have ensured that the next generation of Tracking and Data Relay Satellites (TDRS H, I, J) will comply to the greatest extent possible with NASA's policy on limiting orbital debris generation. The NASA policy has been in effect since 1993; specific guidelines for compliance with the policy were released more recently, and TDRS H, I, J is one of the first programs required to use this system of criteria. The TDRS H, I, J spacecraft is based on an existing spacecraft bus design that already incorporates several features to lower the probability of debris generation. Through extensive analysis and design trade documentation, it has been demonstrated that debris issues themselves will not dictate any design changes, End-of-life disposal will be accomplished by transferring the spacecraft to a supersynchronous orbit and, wherever it is practical, draining on-board sources of stored energy. RP Gagosian, JS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SPACECRAFT PROP GRP,CODE 713,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 119 EP 130 PG 12 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00009 ER PT S AU Flanegan, M LaBel, K AF Flanegan, M LaBel, K BE Culp, RD Wiens, SB TI Radiation hardened electronic component development at GSFC SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB Our experience at Goddard Space Flight Center (GSFC) is that a combination of Commercial-Off-The-Shelf (COTS) and radiation hardened technologies often provide the most cost effective solution for spaceflight applications. Limited availability of COTS components that satisfy certain spacecraft functions has led GSFC and others to develop radiation hardened versions for spaceflight use. This paper provides an introduction to some of these devices, including a high performance processor, mid and high rate on-board communication interfaces and an embedded processor/interface controller. A high density memory module is included because of the importance of bulk data storage to many spacecraft. Although the parts in it are not radiation hard, the module may be used in spaceflight due to a combination of testing and a system level error mitigation approach. RP Flanegan, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 735,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 133 EP 138 PG 6 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00010 ER PT S AU Barnes, C Johnston, A Lee, C Swift, G Rax, B AF Barnes, C Johnston, A Lee, C Swift, G Rax, B BE Culp, RD Wiens, SB TI Radiation effects issues for JPL interplanetary missions SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB In this paper we discuss radiation effects issues that have become important for JPL missions in the last few years. Particularly critical is the increasing usage of commercial off-the-shelf (COTS) devices and circuits in interplanetary missions that experience significant exposure to radiation. Demands for increased performance levels in spacecraft systems will drive the insertion of the latest electronic and photonic devices. Advances in electronics to achieve high performance will result in scaling (miniaturization) of devices, which, in turn, will lead to increased radiation vulnerability in many cases. These issues are discussed within the context of recent technical examples of challenging radiation effects problems. RP Barnes, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 151 EP 167 PG 17 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00012 ER PT S AU Kia, T Bayard, DS Tolivar, F AF Kia, T Bayard, DS Tolivar, F BE Culp, RD Wiens, SB TI A precision pointing control system for the space infrared telescope facility (SIRTF) SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The SIRTF telescope carries on-board imaging, spectroscopy, and photometry instrumentation to investigate fundamental questions about the early universe, formation and evolution of galaxies, and formation of planetary systems, based on infrared astronomical observations. In order to meet stringent science objectives, the Pointing Control System (PCS) must achieve sub-arcsecond pointing accuracy and stability over exposure times in excess of 500 seconds. Requirements are complicated by the use of canning instruments that must be coordinated with PCS mapping maneuvers, in addition to the use of spectrographs requiring the stable placement of poorly known IR objects in the center of narrow slits. Constraints on size, cost and weight of the space telescope impose additional engineering challenges, and demand the effective use of integrated modeling, analysis, simulation, and control design tools. RP Kia, T (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 267 EP 283 PG 17 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00019 ER PT S AU Robertson, BP San, JK Selby, VH AF Robertson, BP San, JK Selby, VH BE Culp, RD Wiens, SB TI On-orbit in the TOMS-EP earth sensors SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Total Ozone Mapping Spectrometer - Earth Probe (TOMS-EP) is an Earth-pointed, pitch momentum bias satellite launched on July 2, 1996. The Attitude Control and Determination System (ACDS) utilizes two identical SCANWHEELs(R), each of which consist of a momentum wheel and a conical Earth Sensor Assembly (ESA). Each ESA provides roll and pitch axis attitude error measurements. These signals are the primary attitude measurements during the Earth Acquisition Mode, the thruster-based Attitude Hold Mode, and the wheel-based Science Mode operations. The ESA signals are also used by the fault detection software to trigger fail-overs to the TOMS-EP Safe Modes. Soon after launch of TOMS-EP, anomalies were observed in the ESA signals. This paper describes the on-orbit processing, operation, and performance of the TOMS-EP ESAs. In addition, on-orbit modifications made to the TOMS-EP software database are described which minimize the impact of anomalous ESA measurements on ACDS performance and the science mission. Finally, a discussion relating the anomaly mechanism to both natural radiation effects and ground-based electromagnetic interference is presented. RP Robertson, BP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 712,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 331 EP 345 PG 15 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00022 ER PT S AU Watzin, JG AF Watzin, JG BE Culp, RD Wiens, SB TI Fast mission start-up, an attitude control stress test SO GUIDANCE AND CONTROL 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 20th Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 05-09, 1997 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Fast Auroral Snapshot Explorer (FAST) spacecraft was launched on August 21, 1996, into a nearly perfect orbit by the Pegasus XL launch vehicle. After a successful turn-on and initial stabilization the mission began deploying its many magnetic, electric field, and particle sensors. FAST had thirteen instrument deployables. All were not destined to work smoothly. One 30 meter wire boom failed to complete its deployment. The spacecraft Attitude Control System (ACS) was called upon to attempt to free the boom. Various unplanned spin-ups, spin-downs, and solar attitudes were developed and tried to unstick this boom. All, sadly, were unsuccessful. However, the scope of these activities pressed the ACS beyond its design limits, proving the robustness and versatility of the system. This paper will describe the FAST spacecraft system, focusing on the unique, unplanned activities associated with the failed wire boom deployment and the spacecraft system performance. RP Watzin, JG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 701-3,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-430-3 J9 ADV ASTRONAUT SCI PY 1997 VL 94 BP 381 EP 395 PG 15 WC Automation & Control Systems; Engineering, Aerospace SC Automation & Control Systems; Engineering GA BJ04Q UT WOS:A1997BJ04Q00025 ER PT B AU Stahle, CM Shi, ZQ Hu, K Barthelmy, SD Snodgrass, SJ Bartlett, LM Shu, PK Lehtonen, SJ Mach, KJ AF Stahle, CM Shi, ZQ Hu, K Barthelmy, SD Snodgrass, SJ Bartlett, LM Shu, PK Lehtonen, SJ Mach, KJ BE Hoover, RB Doty, FP TI Fabrication of CdZnTe strip detectors for large area arrays SO HARD X-RAY AND GAMMA-RAY DETECTOR PHYSICS, OPTICS, AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray and Gamma-Ray Detector Physics, Optics, and Applications CY JUL 31-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE CdZnTe; strip detector; gamma ray; hard x-ray; imaging; spectroscopy; wire bonding; fabrication; testing; array AB A CdZnTe strip detector array with capabilities for are second imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. Two dimensional orthogonal strip detectors with 100 mu m pitch have been fabricated and tested for a large area array (similar to 60 cm(2) with 36 detectors). Details for the fabrication and evaluation of the detectors will be presented. Critical issues to be addressed include fabricating metal contacts with low leakage current and with excellent wire bonding yield, achieving high yield for good strips, and surface cleaning and passivation. RP Stahle, CM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 718-1,GREENBELT,MD 20771, USA. RI Barthelmy, Scott/D-2943-2012 NR 0 TC 29 Z9 29 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2537-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3115 BP 90 EP 97 DI 10.1117/12.277669 PG 8 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BJ31M UT WOS:A1997BJ31M00011 ER PT B AU Kasper, EF Haworth, LA Szoboszlay, ZP King, RD Halmos, ZL AF Kasper, EF Haworth, LA Szoboszlay, ZP King, RD Halmos, ZL BE Lewandowski, RJ Haworth, LA Girolamo, HJ TI Effects of in-flight field of view restriction on rotorcraft pilot head movement SO HEAD-MOUNTED DISPLAYS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Head-Mounted Displays II CY APR 21-22, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE helicopters; field-of-view; pilot workload; visionic systems; night-vision devices; pilot performance; helmet-mounted displays AB The work reported in this paper examines the effect of restricting visual field-of-view(FOV) on rotorcraft pilot head movement. To simulate the FOVs of current and future helmet mounted displays (HMDs) used for night vision pilotage, a FOV restrictor was attached to the helmets of the test subject pilots. The restrictor limited horizontal FOV to 100, 80, 60, 40, and 20 degrees. Ten test subject pilots executed a set of low altitude flight maneuvers in an instrumented NAH-1S helicopter at the NASA Crows' Landing Airfield. Head movement was measured with an infrared head tracker for those pilots who flew in the rear seat and by a video camera for those who flew in the front seat. Test data indicated that pilots responded to restrictions in horizontal FOV by changing their pattern of head movement, both in azimuth and elevation. These compensation strategies change as FOV decreases and vary from pilot to pilot. Test results reported in this paper, in conjunction with referenced data outlining FOV effects on flight performance, handling qualities, and visual cue ratings, give visionic system designers and users predictive information on pilot workload and performance. RP Kasper, EF (reprint author), USA,AVIAT RES DEV & ENGN CTR,NASA,ROTORCRAFT DIV,AEROFLIGHTDYNAM DIRECTORATE,MOFFETT FIELD,CA 94035, USA. NR 0 TC 9 Z9 9 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2473-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3058 BP 34 EP 45 DI 10.1117/12.276658 PG 12 WC Engineering, Aerospace; Computer Science, Cybernetics; Optics SC Engineering; Computer Science; Optics GA BJ12Z UT WOS:A1997BJ12Z00004 ER PT B AU Murray, J AF Murray, J BE Lewandowski, RJ Haworth, LA Girolamo, HJ TI Content and media analysis for intelligent helmet mounted displays SO HEAD-MOUNTED DISPLAYS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Head-Mounted Displays II CY APR 21-22, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE intelligent displays; helmet mounted displays; communicative acts AB The design of intelligent helmet mounted displays (HMDs) requires addressing what information should be presented and how should that information be presented. This paper presents a systematic approach for identifying what information should be displayed, the context sensitive nature of the information, and context dependent means of deciding how to display the information. This approach incorporates the following features. First, the representation of content separate from the means of displaying the information and representation of multiple perspectives of context. Second, the characterization of the display device and the explicit representation of the design problem space for mapping information to display media methods. Third, identification of the worth and cost estimates associated with each information-to-display-method choice. Finally, a mechanism for allocating information to display media methods at both design-time and runtime. The approach provides support for the hierarchical representation of goals using communicative acts, least-commitment constraint posting for display plans, and context sensitive evaluation of worth and cost values used to allocate information to media. This approach also support traceability of design decisions. RP Murray, J (reprint author), NASA,AMES RES CTR,RETICULAR SYST,M-S 243-4,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2473-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3058 BP 86 EP 96 DI 10.1117/12.276663 PG 11 WC Engineering, Aerospace; Computer Science, Cybernetics; Optics SC Engineering; Computer Science; Optics GA BJ12Z UT WOS:A1997BJ12Z00009 ER PT S AU Marsden, RG Smith, EJ AF Marsden, RG Smith, EJ BE Page, DE Marsden, RG TI Ulysses: A summary of the first high-latitude survey SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID HELIOSPHERIC MAGNETIC-FIELD; SOUTH POLAR-REGION; PLASMA OBSERVATIONS; COSMIC-RAY; SOLAR; STREAM; SPEED; ACCELERATION; EXPANSION; PARTICLES AB The unique in-situ observations acquired by the scientific instrumentation on board the Ulysses spacecraft have provided, for the first time, a comprehensive, 3-dimensional view of the heliosphere from the solar equator to the poles near solar minimum. Since beginning its journey out of the ecliptic plane in February, 1992, Ulysses has acquired a wealth of truly new observations concerning the particles and fields in the previously unreachable high-latitude regions of the heliosphere. This paper discusses the status of the mission, and presents a summary of some of the most recent results. (C) 1997 COSPAR. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Marsden, RG (reprint author), EUROPEAN SPACE AGCY,ESTEC,DEPT SPACE SCI,SOLAR SYST DIV,POB 299,NL-2200 AG NOORDWIJK,NETHERLANDS. NR 47 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 825 EP 834 DI 10.1016/S0273-1177(97)00286-X PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00001 ER PT S AU Forsyth, FJ Balogh, A Horbury, TS Smith, EJ AF Forsyth, FJ Balogh, A Horbury, TS Smith, EJ BE Page, DE Marsden, RG TI The heliospheric magnetic field at solar minimum as observed by Ulysses SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID SECTOR STRUCTURE; WIND; SOUTH; POLE AB Since February 1992 the Ulysses spacecraft has been in a polar orbit round the Sun, reaching 80 degrees heliolatitude over the south pole in September 1994 and over the north pole in July 1995. During this time solar activity has been gradually declining towards its present minimum in mid-1996. We discuss how the large scale configuration of the heliospheric magnetic field and its embedded current sheet have evolved throughout this period, based upon measurements obtained by the magnetometer experiment on Ulysses, contrasting the snapshot of the field configuration obtained under solar minimum conditions during the fast transit from south pole to north. pole with the results from earlier years where the slower traversal of latitude allowed effects of the evolution of the corona with solar activity to be more apparent. (C) 1997 COSPAR. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Forsyth, FJ (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. NR 13 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 839 EP 842 DI 10.1016/S0273-1177(97)00288-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00003 ER PT S AU Horbury, TS Balogh, A Forsyth, RJ Smith, EJ AF Horbury, TS Balogh, A Forsyth, RJ Smith, EJ BE Page, DE Marsden, RG TI Ulysses observations of intermittent heliospheric turbulence SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID SOLAR-WIND AB Structure function measurements of small scale magnetic field fluctuations in high speed streams emanating from the Sun's polar coronal holes are well described by a multifractal model of intermittent turbulence. We discuss structure functions and present measurements of intermittency through the transition regime - encompassing scales between waves and inertial range turbulence - and demonstrate that fluctuations in this regime are probably not more or less intermittent than those in the inertial range. The observations are in good agreement with a recently published model of evolving intermittent turbulence. (C) 1997 COSPAR. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Horbury, TS (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,PRINCE CONSORT RD,LONDON SW7 2AZ,ENGLAND. NR 12 TC 37 Z9 38 U1 1 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 847 EP 850 DI 10.1016/S0273-1177(97)00290-1 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00005 ER PT S AU MacDowall, RJ Hess, RA Lin, N Thejappa, G AF MacDowall, RJ Hess, RA Lin, N Thejappa, G BE Page, DE Marsden, RG TI Plasma wave observations from the Ulysses spacecraft's fast heliographic latitude scan SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID SOLAR-WIND; HEAT-FLUX; INSTABILITY; FIELD AB Plasma wave observations obtained by the Ulysses spacecraft in 1994 and 1995 over a heliographic latitude range of -70 to +70 degrees show significantly different wave characteristics inside and outside the streamer belt. Langmuir wave bursts are most commonly found in magnetic holes, especially in fast solar wind. The intensities of ion-acoustic-like waves are reduced at high latitudes. Low frequency electrostatic wave levels show variations that may correlate with solar wind velocity. The maximum levels of whistler waves are correlated with magnetic field magnitude. C1 HUGHES STX,LANHAM,MD 20706. UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. RP MacDowall, RJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI MacDowall, Robert/D-2773-2012 NR 19 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 873 EP 876 DI 10.1016/S0273-1177(97)00295-0 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00010 ER PT S AU Lin, NG Kellogg, PJ MacDowall, RJ Scime, EE Phillips, JL Balogh, A Forsyth, RJ AF Lin, NG Kellogg, PJ MacDowall, RJ Scime, EE Phillips, JL Balogh, A Forsyth, RJ BE Page, DE Marsden, RG TI Low frequency plasma waves in the solar wind: From ecliptic plane to the solar polar regions SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID INTERPLANETARY SHOCKS; HEAT-FLUX; RADIO AB Traveling from the ecliptic to the solar polar regions, Ulysses observed wave activity below the local electron cyclotron frequency f(ce). In regions near the heliospheric current sheet (hereafter HCS regions), two wave modes are observed: (1) whistler mode electromagnetic waves near interplanetary shocks and during periods of rapidly increasing solar wind velocity, and (2) apparently electrostatic waves occurring during the periods when gradually decreasing solar wind velocity is observed. At high heliographic latitudes, in the region with relatively steady high speed solar wind streams, wave activity is consistently observed near and below f(ce) with little time variability of the spectra. It is found that in the periods when intense waves of the second type are observed in the HCS regions, the electron heat flux decreases. This may imply that these law frequency waves limit the intensity of the heat flux through wave particle scattering. (C) 1997 COSPAR. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. W VIRGINIA UNIV,DEPT PHYS,MORGANTOWN,WV 26506. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON,ENGLAND. RP Lin, NG (reprint author), UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455, USA. RI MacDowall, Robert/D-2773-2012 NR 13 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 877 EP 881 DI 10.1016/S0273-1177(97)00296-2 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00011 ER PT S AU Gangopadhyay, P Judge, DL Liewer, PC AF Gangopadhyay, P Judge, DL Liewer, PC BE Page, DE Marsden, RG TI Pioneer 10 and Voyagers 1 and 2 backscattered UV data and the nature of the interstellar medium SO HELIOSPHERE AT SOLAR MINIMUM AND BEYOND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT DO-2 Symposium of COSPAR Scientific Commission D on the Heliosphere at Solar Minimum and Beyond, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID TERMINATION SHOCK; HYDROGEN AB It has not yet been unambiguously established whether the bulk velocity of the very local interstellar medium (VLISM) relative to the Sun is subsonic or supersonic. Till now there has been no way to decide between the two possibilities although the backscattered UV data base obtained from the Pioneer 10 and Voyagers 1 and 2 missions in principle contain the required information. The principal difficulty in interpreting the UV data has been the lack of self-consistent heliospheric models. In recent years, however, several self-consistent models have become available. We have used two two-dimensional axisymmetric hydrodynamic models of the heliosphere developed by one of the authors for both supersonic and subsonic VLISM flow and compared their predictions with the observed backscattered Lyman-cr data. We found that neither model can satisfactorily reproduce the observed Pioneer 10 and Voyager 2 UV data except for the large distance Pioneer 10 downstream UV data. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Gangopadhyay, P (reprint author), UNIV SO CALIF,DEPT PHYS & ASTRON,LOS ANGELES,CA 90089, USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043107-0 J9 ADV SPACE RES PY 1997 VL 19 IS 6 BP 957 EP 960 DI 10.1016/S0273-1177(97)00312-8 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH99D UT WOS:A1997BH99D00027 ER PT S AU Hollenbach, D AF Hollenbach, D BE Reipurth, B Bertout, C TI The physics of molecular shocks in YSO outflows SO HERBIG-HARO FLOWS AND THE BIRTH OF LOW MASS STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 182nd Symposium of the International-Astronomical-Union on Herbig-Haro Flows and the Birth of Low Mass Stars CY JAN 20-26, 1997 CL CHAMONIX, FRANCE SP Int Astron Union ID C-TYPE SHOCKS; H2O MASERS; INTERSTELLAR SHOCKS; INFRARED-EMISSION; DIFFUSE CLOUDS; YOUNG STARS; WAVES; LINE; ORION; JETS AB Shock waves light up the jets, winds and outflows around YSOs and diagnose the physical conditions and processes resident in these regions. This paper discusses the differences between the jet/wind shock and the ambient shock, between C shocks and J shocks, and between the shocks produced by pure jets and by collimated wide angle winds. Basic shock physics is briefly reviewed, with a special focus on the temperature structure in shocks and the Wardle instability of C shocks. Application is made to the origin of shocked H-2 emission and to H2O masers. RP Hollenbach, D (reprint author), NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 61 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4660-2 J9 IAU SYMP PY 1997 IS 182 BP 181 EP 198 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ28R UT WOS:A1997BJ28R00016 ER PT S AU Stapelfeldt, K Burrows, CJ Krist, JE AF Stapelfeldt, K Burrows, CJ Krist, JE BE Reipurth, B Bertout, C TI Hubble Space Telescope imaging of the disks and jets of Taurus young stellar objects SO HERBIG-HARO FLOWS AND THE BIRTH OF LOW MASS STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 182nd Symposium of the International-Astronomical-Union on Herbig-Haro Flows and the Birth of Low Mass Stars CY JAN 20-26, 1997 CL CHAMONIX, FRANCE SP Int Astron Union ID HERBIG-HARO JET; POPULATION; OUTFLOWS; CLOUDS; STAR AB We report on Hubble Space Telescope imaging of eleven young stellar objects in the nearby Taurus molecular clouds. The high spatial resolution and stable point spread function of HST reveal important new details of the circumstellar nebulosity of these objects. Three sources (HH 30, FS Tau B, and DG Tau B) are resolved as compact bipolar nebulae without a directly visible star. In all three cases, jet widths near the sources are found to be 50 AU or less. Flattened disk structures are seen in absorption in HH 30 and FS Tau B, and in reflection about GM Aur. Extended envelope structures traced by scattered light are present in HL large opening angle and is already resolved into a bow-like structure less than 3 '' from the star. C1 SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. RP Stapelfeldt, K (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MAIL STOP 183-900, PASADENA, CA 91109 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 26 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4660-2 J9 IAU SYMP PY 1997 IS 182 BP 355 EP 364 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ28R UT WOS:A1997BJ28R00029 ER PT S AU Bell, KR Chick, KM AF Bell, KR Chick, KM BE Reipurth, B Bertout, C TI The radiative impact of FU Orionis outbursts on protostellar envelopes SO HERBIG-HARO FLOWS AND THE BIRTH OF LOW MASS STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 182nd Symposium of the International-Astronomical-Union on Herbig-Haro Flows and the Birth of Low Mass Stars CY JAN 20-26, 1997 CL CHAMONIX, FRANCE SP Int Astron Union ID DISK MODELS; YOUNG STARS; EVOLUTION; VARIABLES; OUTFLOW AB We present preliminary results of an investigation into the radiative impact of FU Orionis outbursts on protostellar envelopes. In the thermal accretion disk instability model, the inner portion of the disk is inflated in such a way as to funnel most of the outburst luminosity along the poles of the system. A multidimensional radiative transfer code is employed to derive the thermal equilibrium structure of the surrounding protostellar envelope and the backheated accretion disk during outburst. The radiation emitted during outburst is modeled as a combination of a self-luminous accretion disk and a central point source. We compare the relative heating of circumstellar material due to (1) an isotropic point source and (2) an anisotropic point source in which the emitted radiation is confined to a 30 degrees cone about the polar axis. The isotropic point source creates a spherical dust cavity, while the anisotropic source naturally results in a cavity which is hourglass-shaped. Repeated outbursts may ultimately be responsible for the large-scale polar cavities commonly inferred to exist around young stellar objects. We also show that due to the anisotropy of the radiation expected during outburst, disk annuli within a few au will be shielded from the radiation of the outburst. RP Bell, KR (reprint author), NASA, AMES RES CTR, DIV SPACE SCI, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4660-2 J9 IAU SYMP PY 1997 IS 182 BP 407 EP 416 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ28R UT WOS:A1997BJ28R00033 ER PT S AU Terebey, S Padgett, DL AF Terebey, S Padgett, DL BE Reipurth, B Bertout, C TI Millimeter interferometry of class 0 sources: Rotation and infall towards L1448N SO HERBIG-HARO FLOWS AND THE BIRTH OF LOW MASS STARS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 182nd Symposium of the International-Astronomical-Union on Herbig-Haro Flows and the Birth of Low Mass Stars CY JAN 20-26, 1997 CL CHAMONIX, FRANCE SP Int Astron Union ID BIPOLAR OUTFLOW; CLOUDS AB In order to study the kinematics of protostellar collapse we present high-spatial resolution millimeter interferometer data of the class 0 source L1448 N. The L1448 N cloud core has fragmented into two rapidly rotating subcores containing three protostars. One subcore is a protobinary system with 2000 AU separation. Strong evidence for infall is seen towards the N(B) component. C1 CALTECH, JET PROP LAB, PASADENA, CA 91125 USA. RP Terebey, S (reprint author), EXTRASOLAR RES GRP, 720 MAGNOLIA AVE, PASADENA, CA 91106 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4660-2 J9 IAU SYMP PY 1997 IS 182 BP 507 EP 514 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ28R UT WOS:A1997BJ28R00042 ER PT S AU Shao, M AF Shao, M BE Lagrange, AM Mourard, D Lena, P TI Astrometry with O/IR interferometers SO HIGH ANGULAR RESOLUTION IN ASTROPHYSICS SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on High Angular Resolution in Astrophysics CY APR 09-19, 1996 CL LES HOUCHES, FRANCE SP NATO, Adv Study Inst AB This paper is a tutorial on astrometry with long baseline ground based interferometers. There are two types of astrometric measurements with ground based interferometers, global astrometry and narrow angle astrometry. The ultimate limits for both types of measurements are set by the atmosphere. However the instrumental considerations for the two types of measurements are quite different. This paper gives an overview of the instrumental aspects of these two different types of astrometric instruments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shao, M (reprint author), CALTECH, Jet Prop Lab, 306-388,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-4767-6 J9 NATO ADV SCI I C-MAT PY 1997 VL 501 BP 109 EP 114 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK72Q UT WOS:000073224300006 ER PT B AU Newman, JC AF Newman, JC BE Soboyejo, WO Srivatsan, TS TI Crack growth under variable amplitude and spectrum loading in 2024-T3 aluminum alloys SO HIGH CYCLE FATIGUE OF STRUCTURAL MATERIALS LA English DT Proceedings Paper CT Symposium on High Cycle Fatigue of Structural Materials in Honor of Professor Paul C Paris, Held During Materials Week 97 CY SEP 14-18, 1997 CL INDIANAPOLIS, IN SP Minerals Met & Mat Soc, Struct Mat Div, ASM Int AB This paper is dedicated to Professor Paul C. Paris and is concerned with the application of a "plasticity-induced" crack closure model to study fatigue crack growth under various load histories. The model is based on the Dugdale model but accounts for constraint effects (plane-strain to plane-stress transition) on crack growth behavior. The model was used to correlate crack growth rate data under constant-amplitude loading and was then used to predict crack growth under variable-amplitude and spectrum loading on several thin-sheet 2024-T3 aluminum alloys. Crack-opening stresses from the model agreed fairly well with test measurements from the literature. Crack-growth lives agreed within a factor of two for spike overload-underload tests and for two different wing load spectra. Some of the differences were attributed to fretting-product-debris-induced closure and three-dimensional effects not included in the model. C1 NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Mech Mat Branch, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-382-1 PY 1997 BP 109 EP 121 PG 13 WC Engineering, Mechanical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Engineering; Materials Science; Metallurgy & Metallurgical Engineering GA BK49Y UT WOS:000072372400009 ER PT S AU Horn, TJ Richards, WL Gong, L AF Horn, TJ Richards, WL Gong, L BE Khounsary, AM Macrander, AT TI A technique for transient thermal testing of thick structures SO HIGH HEAT FLUX AND SYNCHROTRON RADIATION BEAMLINES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 4th High Heat Flux Engineering Conference, as part of the SPIE International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 28-29, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE structural tests; thermal testing; radiant heating; transient thermal simulation; heat flux; heat transfer AB A new open-loop heat flux control technique has been developed to conduct transient thermal testing of thick, thermally-conductive aerospace structures. This technique uses calibration of the radiant heater system power level as a function of heat flux, predicted aerodynamic heat flux, and the properties of an instrumented test article. An iterative process was used to generate open-loop heater power profiles prior to each transient thermal test. Differences between the measured and predicted surface temperatures were used to refine the heater power level command profiles through the iteration process. This iteration process has reduced the effects of environmental and test system design factors, which are normally compensated for by closed-loop temperature control, to acceptable levels. The final revised heater power profiles resulted in measured temperature time histories which deviated less than 25 degrees F from the predicted surface temperatures. C1 NASA, Dryden Flight Res Ctr, Edwards, CA 93523 USA. RP Horn, TJ (reprint author), NASA, Dryden Flight Res Ctr, MS 48202A,POB 273, Edwards, CA 93523 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2573-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3151 BP 73 EP 91 DI 10.1117/12.294500 PG 19 WC Engineering, Mechanical; Optics SC Engineering; Optics GA BK21Q UT WOS:000071550400007 ER PT S AU Drummond, LA Farrara, JD Mechoso, CR Lou, JZ AF Drummond, LA Farrara, JD Mechoso, CR Lou, JZ BE Hertzberger, B Sloot, P TI Performance optimization of an atmospheric model in massively parallel computers SO HIGH-PERFORMANCE COMPUTING AND NETWORKING SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT High Performance Computing and Networking Europe 1997 Conference CY APR 28-30, 1997 CL VIENNA, AUSTRIA ID GENERAL-CIRCULATION MODEL AB This paper discusses optimization issues to be addressed in producing a major improvement in the performance of a state-of-the-art general circulation model of the atmosphere on massively parallel computer systems. Our work is based on the UCLA Atmospheric General Circulation Model (AGCM). The UCLA AGCM is a "grid-point model", which uses a three dimensional staggered grid to compute flow variables around the globe. The current goal is to produce a code that runs at the 50 GFLOP level by early 1998. We focus on load balancing strategies and single node optimization techniques. The target architecture for the single node optimization is the GRAY T3D. In the near future, the work will be extended to the GRAY T3E. This research is been carried out in the framework of NASA High Performance Computing and Communication program (BPCC). C1 Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. RP Drummond, LA (reprint author), Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN 33 PA HEIDELBERGER PLATZ 3, W-1000 BERLIN 33, GERMANY SN 0302-9743 BN 3-540-62898-3 J9 LECT NOTES COMPUT SC PY 1997 VL 1225 BP 263 EP 271 PG 9 WC Computer Science, Information Systems; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BK98Z UT WOS:000074015300026 ER PT B AU Yao, XS Maleki, L AF Yao, XS Maleki, L BE Kwong, NS Nagarajan, R TI Opto-electronic oscillator and its applications SO HIGH-SPEED SEMICONDUCTOR LASERS FOR COMMUNICATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on High-Speed Semiconductor Lasers for Communication CY FEB 10-11, 1997 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE oscillator; opto-electronics; microwave; electro-optic modulator; laser; phase noise; optical pulses AB We review the properties of a new class of microwave oscillators called opto-electronic oscillators (OEO). We present theoretical and experimental results of a multi-loop technique for single mode selection. We then describe a new development called coupled OEO (COEO) in which the electrical oscillation is directly coupled with the optical oscillation, producing an OEO that generates stable optical pulses and single mode microwave oscillation simultaneously. Finally we discuss various applications of OEO. RP Yao, XS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2449-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3038 BP 97 EP 107 DI 10.1117/12.271449 PG 3 WC Optics; Telecommunications SC Optics; Telecommunications GA BH66G UT WOS:A1997BH66G00012 ER PT S AU Jacobson, NS AF Jacobson, NS BE Streiff, R Stringer, J Krutenat, RC Caillet, M Rapp, RA TI Use of a free-jet expansion, molecular beam mass spectrometer to understand processes involving volatile corrosion products SO HIGH TEMPERATURE CORROSION AND PROTECTION OF MATERIALS 4, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th International Symposium on High Temperature Corrosion and Protection of Materials CY MAY 20-24, 1996 CL LES EMBIEZ, FRANCE SP CEFRACOR, Paris, France, Univ Provence, Marseille, France, E P R I, Palo Alto, US, European Federat Corros Event No 207 DE volatile products; mass spectrometry; chlorination; hydroxyl species ID OXIDATION-CHLORINATION; GAS AB Many high-temperature corrosion processes generate volatile products in addition to condensed phase products. Examples of these volatile products are chlorides, oxychlorides, and certain oxides and hydroxyl species. One of the best techniques to identify high temperature vapor molecules is mass spectrometry. Most mass spectrometers operate in high vacuum and are generally used to examine processes ocurring at greatly reduced pressures. However, a free-jet expansion, molecular beam mass spectrometer system allows direct sampling of volatile corrosion products. This instrument is described. Several examples from our studies on chlorination/oxidation of metals and ceramics are discussed. In addition, reactions of Cr2O3, SiO2, and Al2O3 with water vapor, which produce volatile hydroxyl species are discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Jacobson, NS (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RI Jacobson, Nathan/A-9411-2009 NR 19 TC 0 Z9 0 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-774-9 J9 MATER SCI FORUM PY 1997 VL 251-2 BP 235 EP 242 PN 1-2 PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK31U UT WOS:000071768900028 ER PT S AU Sarioglu, S Blachere, JR Pettit, FS Meier, GH Smialek, JL Mennicke, C AF Sarioglu, S Blachere, JR Pettit, FS Meier, GH Smialek, JL Mennicke, C BE Streiff, R Stringer, J Krutenat, RC Caillet, M Rapp, RA TI The effects of reactive element additions, sulfur removal, and specimen thickness on the oxidation behaviour of alumina-forming Ni- and Fe-base alloys SO HIGH TEMPERATURE CORROSION AND PROTECTION OF MATERIALS 4, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th International Symposium on High Temperature Corrosion and Protection of Materials CY MAY 20-24, 1996 CL LES EMBIEZ, FRANCE SP CEFRACOR, Paris, France, Univ Provence, Marseille, France, E P R I, Palo Alto, US, European Federat Corros Event No 207 DE alumina; adherence; Fe-base alloys; Ni-base alloys; cyclic oxidation; stress in alumina scales ID OXIDE SCALE ADHERENCE; MECHANISM; RESISTANCE; ADHESION AB The effects of sulfur content, specimen thickness, and reactive element additions on the isothermal and cyclic oxidation behavior of a variety of alumina-forming alloys have been studied. These alloys include: single crystal Ni-base superalloys, ferritic Fe-Cr-Al alloys, and NiAl. The results have shown that desulfurization by hydrogen annealing decreases the amount of interface void formation and can result in improvements in cyclic oxidation comparable to that achieved by doping with reactive elements. The results have also indicated that there is less stress generation during the cyclic oxidation of Y-doped FeCrAl compared to Ti-doped or desulfurized FeCrAl. This indicates that the growth mechanism, as well as the strength of the oxide/alloy interface is influenced by Y additions, The effects of Al depletion from thin specimens, which leads to breakaway oxidation, has also been evaluated. C1 Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Max Planck Inst Metallforsch, Stuttgart, Germany. RP Sarioglu, S (reprint author), Univ Pittsburgh, Dept Mat Sci & Engn, Pittsburgh, PA 15261 USA. NR 28 TC 8 Z9 8 U1 0 U2 3 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-774-9 J9 MATER SCI FORUM PY 1997 VL 251-2 BP 405 EP 412 PN 1-2 PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK31U UT WOS:000071768900048 ER PT S AU Jacobson, NS Opila, EJ Fox, DS Smialek, JL AF Jacobson, NS Opila, EJ Fox, DS Smialek, JL BE Streiff, R Stringer, J Krutenat, RC Caillet, M Rapp, RA TI Oxidation and corrosion of silicon-based ceramics and composites SO HIGH TEMPERATURE CORROSION AND PROTECTION OF MATERIALS 4, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th International Symposium on High Temperature Corrosion and Protection of Materials CY MAY 20-24, 1996 CL LES EMBIEZ, FRANCE SP CEFRACOR, Paris, France, Univ Provence, Marseille, France, E P R I, Palo Alto, US, European Federat Corros Event No 207 DE ceramics; silicon carbide; silicon nitride; composites; silica; oxidation; corrosion by molten salts ID TEMPERATURE ACTIVE OXIDATION; CARBIDE; SI3N4; VAPOR; KINETICS; ENVIRONMENTS; ATMOSPHERE; INTERFACE; COATINGS; MODEL AB Silica scales exhibit slow growth rates and a low activation energy. Thus silica-protected materials are attractive high temperature: structural materials for their potentially excellent oxidation resistance and well-documented high temperature strength. This review focuses on silicon carbide, silicon nitride, and composites of these materials. It is divided into four parts: (i) Fundamental oxidation mechanisms, (ii) Special properties of silica scales, (iii) Protective coatings, and (iv) Internal oxidation behavior of composites. While the fundamental oxidation mechanism of SiC is understood, there are still many questions regarding the oxidation mechanism of Si3N4. Silica scales exhibit many unique properties as compared to chromia and alumina. These include slower growth rates, SiO(g) formation, sensitivity to water vapor and impurities, and dissolution by basic molten salts. Protective coatings can limit the deleterious effects. The fourth area-internal oxidation of fibers and fiber coatings in composites-has limited the application of these novel materials. Strategies for understanding and limiting this internal oxidation are discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, NASA Lewis, Cleveland, OH 44135 USA. RP Jacobson, NS (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RI Jacobson, Nathan/A-9411-2009 NR 49 TC 15 Z9 15 U1 0 U2 5 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-774-9 J9 MATER SCI FORUM PY 1997 VL 251-2 BP 817 EP 831 PN 1-2 PG 15 WC Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK31U UT WOS:000071768900096 ER PT S AU Garg, A Whittenberger, JD Luton, MJ AF Garg, A Whittenberger, JD Luton, MJ BE Koch, CC Liu, CT Stoloff, NS Wanner, A TI Microstructure and strengthening of creep-tested cryomilled NiAl-AlN SO HIGH-TEMPERATURE ORDERED INTERMETALLIC ALLOYS VII SE MATERIALS RESEARCH SOCIETY CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Symposium on High-Temperature Ordered Intermetallic Alloys VII CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc AB The mechanical grinding of prealloyed NiAl powder in liquid nitrogen (cryomilling) results in an intermetallic matrix composite where micron sized particle free aluminide cores (grains) are surrounded by thin mantles comprised of nanometer sized AlN particles and NiAl grains. Under high temperature, slow strain rate conditions both compressive and tensile creep testing have shown that the mechanical strength of hot extruded cryomilled NiAl approaches the levels exhibited by advanced NiAl-based single crystals and simple Ni-based superalloys. Transmission electron microscopy of cryomilled materials tested between 1100 and 1300 K revealed little, if any, dislocation structure within the mantle regions, while the NiAl cores contained subgrains and dislocation networks after testing at all strain rates between 10(-4) and 10(-8) s(-1). These and other microstructural observations suggest that creep strength is the result of a fine NiAl grain/subgrain size, the inability of dislocations to move through the mantle and stabilization of the microstructure by the AlN particles. RP Garg, A (reprint author), NASA,LEWIS RES CTR,AYT,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0886-7860 BN 1-55899-364-9 J9 MAT RES S C PY 1997 VL 460 BP 413 EP 418 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BJ28E UT WOS:A1997BJ28E00060 ER PT S AU Raj, SV Garg, A Bieler, TR AF Raj, SV Garg, A Bieler, TR BE Koch, CC Liu, CT Stoloff, NS Wanner, A TI Comparison of the creep properties of cast and powder metallurgy-extruded binary NiAl SO HIGH-TEMPERATURE ORDERED INTERMETALLIC ALLOYS VII SE MATERIALS RESEARCH SOCIETY CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Symposium on High-Temperature Ordered Intermetallic Alloys VII CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc AB A comparison of published creep data on binary NiAl showed that there is a discrepancy in the reported magnitudes of the stress exponents, n, which usually vary between about 4.5 and 6.5. In general, a close examination of the data suggested that n approximate to 4.5 for cast materials and 6.5 for powder-metallurgy extruded NiAl. Constant load compression creep tests were conducted on a cast and extruded binary NiAl between 800 and 1200 K over a wide range of initial applied stresses varying between 4.0 and 200 MPa, The microstructures were characterized by transmission electron microscopy. The observed variations in the creep behavior of the extruded cast and powder-metallurgy NiAl appeared to be due to a grain size effect. Despite similarities in the values of n, no significant substructure was observed in most of the grains in the cast and extruded specimens at 1100 and 1200 K in contrast to the PM-extruded alloy, which revealed a wide range of substructural features in the power-law creep region. However, extensive subgrain formation and dislocations were widely observed at lower temperatures and higher stresses in the cast and extruded material. RP Raj, SV (reprint author), NASA,LEWIS RES CTR,MS 24-1,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0886-7860 BN 1-55899-364-9 J9 MAT RES S C PY 1997 VL 460 BP 473 EP 478 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BJ28E UT WOS:A1997BJ28E00070 ER PT S AU Whittenberger, JD Grahle, P Arzt, E Behr, R Zoltzer, K Hebsur, M AF Whittenberger, JD Grahle, P Arzt, E Behr, R Zoltzer, K Hebsur, M BE Koch, CC Liu, CT Stoloff, NS Wanner, A TI Powder processing of NiAl for elevated temperature strength SO HIGH-TEMPERATURE ORDERED INTERMETALLIC ALLOYS VII SE MATERIALS RESEARCH SOCIETY CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Symposium on High-Temperature Ordered Intermetallic Alloys VII CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc AB In an effort to superimpose two different elevated temperature strengthening mechanisms in NiAl one lot of an oxide dispersion strengthened (ODS) NiAl powder has been milled in liquid nitrogen (cryomilled) to introduce AIN particles at the grain boundaries, and a second lot of ODS powder was simply roasted in gaseous nitrogen as an alternative means to produce AIN reinforced grain boundaries. Powder from both of these lots as well as the starting material have been consolidated by hot extrusion and tested at 1300 K. Both nitrogen roasting and cryomilling produced AIN within the ODS NiAl matrix which strengthened the alloy; however, based on the AIN content, cryomilling is more effective. RP Whittenberger, JD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0886-7860 BN 1-55899-364-9 J9 MAT RES S C PY 1997 VL 460 BP 487 EP 492 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BJ28E UT WOS:A1997BJ28E00072 ER PT S AU GarciaSanchez, J Preston, RA Jones, DL Weissman, PR Lestrade, JF Latham, DW Stefanik, RP AF GarciaSanchez, J Preston, RA Jones, DL Weissman, PR Lestrade, JF Latham, DW Stefanik, RP BE OFlaherty, KS TI A search for stars passing close to the sun SO HIPPARCOS VENICE '97 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Hipparcos Venice 97 CY MAY 13-16, 1997 CL VENICE, ITALY SP European Space Sgcy, City Venice, Fdn Cini DE space astrometry; comets, general; Stars, distances; stars, kinematics AB We have combined Hipparcos proper motion and parallax data for nearby stars with ground-based radial velocity measurements to find stars which may have passed (or will pass) close enough to the Sun to perturb the Oort cloud. Close stellar encounters could deflect large numbers of comets into the inner solar system, with possibly serious consequences for the impact hazard on the Earth. Only one star (Gliese 710) is found with a predicted closest approach of less than 0.5 parsec, although several stars come within about 1 parsec during a +/-8.5 Myr interval. In most cases the uncertainty in closest approach distance is dominated either by uncertainties in published radial velocity measurements or by uncertainties in the barycentric motion of binary systems. We have begun a program to obtain new radial velocities for stars in our sample with no previously published values. RP GarciaSanchez, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-291-5 J9 ESA SP PUBL PY 1997 VL 402 BP 617 EP 620 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ70B UT WOS:A1997BJ70B00145 ER PT S AU Boden, A Unwin, S Shao, M AF Boden, A Unwin, S Shao, M BE OFlaherty, KS TI Global astrometry with the space interferometry mission SO HIPPARCOS VENICE '97 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Hipparcos Venice 97 CY MAY 13-16, 1997 CL VENICE, ITALY SP European Space Sgcy, City Venice, Fdn Cini DE space astrometry; microarcsec astrometry; optical interferometry AB In this paper we will discuss the prospects for global astrometric measurements with the Space Interferometry Mission (SIM). SIM will perform four microarcsec astrometric measurements on objects as dim as 20th magnitude using optical interferometric techniques with a 10 m baseline. SIM performs both narrow-angle astrometry and global astrometry by means of an astrometric grid. We will report on sensitivities of SIM global astrometric performance and grid accuracy versus instrumental parameters and sky coverage schemes. The problems in finding suitable astrometric grid objects to support microarcsec astrometry, and ground-based observing programs that address these issues will be discussed. RP Boden, A (reprint author), CALTECH,JET PROPULS LAB,PASADENA,CA 91125, USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-291-5 J9 ESA SP PUBL PY 1997 VL 402 BP 789 EP 793 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ70B UT WOS:A1997BJ70B00178 ER PT B AU Mosier, KL Heers, S Skitka, LJ Burdick, M AF Mosier, KL Heers, S Skitka, LJ Burdick, M BE Mouloua, M Koonce, JM TI Patterns in the use of cockpit automation SO HUMAN-AUTOMATION INTERACTION: RESEARCH AND PRACTICE LA English DT Proceedings Paper CT 2nd Automation Technology and Human Performance Conference CY MAR 07-09, 1996 CL COCOA BEACH, FL SP Catholic Univ Amer, Cognit Sci Lab, Univ Cent Florida, Ctr Appl Human Factors Aviat, Univ Cent Florida, Coll Arts & Sci, USN, Off Naval Res, NASA, Langley Res Ctr RP Mosier, KL (reprint author), NASA,AMES RES CTR,MS 262-4,MOFFETT FIELD,CA 94035, USA. NR 0 TC 6 Z9 6 U1 1 U2 1 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 BN 0-8058-2841-9 PY 1997 BP 167 EP 173 PG 7 WC Engineering, Aerospace; Computer Science, Cybernetics; Ergonomics SC Engineering; Computer Science GA BH32S UT WOS:A1997BH32S00023 ER PT B AU Watson, AB Borthwick, R Taylor, M AF Watson, AB Borthwick, R Taylor, M BE Rogowitz, BE Pappas, TN TI Image quality and entropy masking SO HUMAN VISION AND ELECTRONIC IMAGING II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging II CY FEB 10-13, 1997 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, Soc Photo Opt Instrumentat Engineers DE noise; contrast gain control; normalization; pattern recognition; signal detection theory; spatial vision; background; entropy masking; image compression; DCTune AB Image quality models usually include a mechanism whereby artifacts are masked by the image acting as a background Scientific study of visual masking has followed two traditions: contrast masking and noise masking, depending primarily on whether the mask is deterministic or random. In the former tradition, masking is explained by a decrease in the effective gain of the early visual system. In the latter tradition, masking is explained by an increased variance in some internal decision variable. The masking process in image quality models is usually of the gain-control variety, derived from the contrast masking tradition. In this paper we describe a third type of masking, which I call entropy masking, that arises when the mask is deterministic but unfamiliar. Some properties and implication of entropy masking are discussed. we argue that image quality models should incorporate entropy masking, as well as contrast masking. RP Watson, AB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 37 Z9 37 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2427-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3016 BP 2 EP 12 DI 10.1117/12.274501 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BJ06U UT WOS:A1997BJ06U00001 ER PT B AU Ahumada, AJ Beard, BL AF Ahumada, AJ Beard, BL BE Rogowitz, BE Pappas, TN TI Image discrimination models: Detection in fixed and random noise SO HUMAN VISION AND ELECTRONIC IMAGING II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging II CY FEB 10-13, 1997 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, Soc Photo Opt Instrumentat Engineers DE vision models; image discrimination; signal detection; visual masking; noise masking; internal noise AB Image discrimination models are used to predict the visibility of the difference between two images. Using a four category rating scale method, Rohaly et al. (SPIE Vol. 2411) and Ahumada & Beard (SPIE Vol. 2657) found that image discrimination models can predict target detectability when the background is kept constant, or 'fixed'. In Experiment I, we use this same rating scale method and find no difference between 'fixed' and 'random' noise (where the white noise changes from trial to trial). In Experiment II, we compare fixed noise and two random noise conditions. Using a two-interval forced-choice procedure, the 'random' noise was tither the same or different in the two intervals. Contrary to image discrimination model predictions, the same random noise condition produced greater masking than the 'fixed' noise. This suggests that observers use less efficient target templates than image discrimination models implicitly assume. Also, performance appeared limited by internal process variability rather than external noise variability since similar masking was obtained for both random noise types. RP Ahumada, AJ (reprint author), NASA,AMES RES CTR,MS 262-2,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2427-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3016 BP 34 EP 43 PG 10 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BJ06U UT WOS:A1997BJ06U00004 ER PT B AU Mulligan, JB AF Mulligan, JB BE Rogowitz, BE Pappas, TN TI Application of temporal error diffusion to motion-JPEG SO HUMAN VISION AND ELECTRONIC IMAGING II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Human Vision and Electronic Imaging II CY FEB 10-13, 1997 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, Soc Photo Opt Instrumentat Engineers DE motion; motion JPEG; M-JPEG; error diffusion; temporal contrast sensitivity; visual quality AB The term error diffusion has been used in the halftoning literature to describe processes in which pixels' quantization errors are spread in space to their unquantized neighbors, causing neighboring errors to be negatively correlated and relatively invisible. The general principle may be extended to the time dimension as well, which we will refer to as temporal error diffusion In this paper we will consider the use of temporal error diffusion to ameliorate the errors introduced by JPEG image compression of a stream of images. RP Mulligan, JB (reprint author), NASA,AMES RES CTR,MS 262-2,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2427-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3016 BP 288 EP 295 DI 10.1117/12.274524 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BJ06U UT WOS:A1997BJ06U00029 ER PT S AU Heymann, M Lin, F Meyer, G AF Heymann, M Lin, F Meyer, G BE Maler, O TI Control synthesis for a class of hybrid systems subject to configuration-based safety constraints SO HYBRID AND REAL-TIME SYSTEMS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on Hybrid and Real-Time Systems (HART 97) CY MAR 26-28, 1997 CL GRENOBLE, FRANCE SP European Community ID DISCRETE AB We examine a class of hybrid systems called Composite Hybrid Machines (CHMs), that consist of the concurrent (and partially synchronized) operation of Elementary Hybrid Machines (EHMs). Legal behavior is specified by a set of illegal configurations that the CHM may not enter, and is to be achieved by the concurrent operation of the CHM with a suitably designed legal controller. A legal controller is minimally restrictive if, when composed to operate concurrently with another legal controller, it will never interfere with the operation of the other controller. We focus attention on the problem of synthesizing a minimally restrictive legal controller, whenever a legal controller exists. We present an algorithm for the synthesis of minimally restrictive legal controllers for CHMs with rate-limited dynamics, where legal guards are conjunctions or disjunctions of atomic formulas in the dynamic variables (of the type x less than or equal to x(o) or x greater than or equal to x(o)). We demonstrate our approach by synthesizing a minimally restrictive controller for a steam boiler (the verification of which recently received a great deal of attention). C1 Technion Israel Inst Technol, Dept Comp Sci, IL-32000 Haifa, Israel. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Wayne State Univ, Dept Elect & Comp Engn, Detroit, MI 48202 USA. RP Heymann, M (reprint author), Technion Israel Inst Technol, Dept Comp Sci, IL-32000 Haifa, Israel. EM heymann@cs.technion.ac.il; flin@ece.eng.wayne.edu; meyer@tarski.arc.nasa.gov NR 20 TC 10 Z9 10 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN 33 PA HEIDELBERGER PLATZ 3, W-1000 BERLIN 33, GERMANY SN 0302-9743 BN 3-540-62600-X J9 LECT NOTES COMPUT SC PY 1997 VL 1201 BP 376 EP 390 PG 15 WC Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA BK20X UT WOS:000071535700033 ER PT S AU Bibring, JP Borg, J Bunch, T Chardin, A Deshpande, S Jolly, H Maag, C Mandeville, JC McDonnell, JAM Nishioka, K Salvetat, P Stevenson, T Vassent, B AF Bibring, JP Borg, J Bunch, T Chardin, A Deshpande, S Jolly, H Maag, C Mandeville, JC McDonnell, JAM Nishioka, K Salvetat, P Stevenson, T Vassent, B BE McDonnell, JAM Spohn, T Mohlmann, D Klinger, J TI The ESEF instrument: A European facility for exposing active and passive particle detectors in low Earth orbits SO HYPERVELOCITY IMPACTS IN SPACE AND PLANETOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO.8, BO.3 and BO.5 Symposium of COSPAR Scientific Commission B on Hypervelocity Impacts in Space and Planetology, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, Int Union Geodesy & Geophys, European Space Agcy, European Geophys Soc AB In the context of dust collections in space, the COMET experiment (Collecte en Orbite de Matiere Extra Terrestre) was proposed in 1982 and has been accepted in 1985 in the framework of the Soviet French space cooperation program. The idea of such an experiment was to install collectors inside hermetic boxes, to have these boxes mounted outside a space station, orbiting the Earth and to have the capability of chosing the date and duration of the collection. In February 94, it has been proposed to fly an improved version of this instrument, as part of the payload of the EUROMIR 95 mission. Renamed as the European Space Exposure Facility (ESEF), it carries experiments from several principal investigators (PIs). These experiments have been designed to analyse in real time some parameters of the encountered particles and to collect material, both of terrestrial and extraterrestrial origin, to be brought back to the Earth at the end of the mission. Three types of collecting material are used: high purity metals, foams and silica aerogels. All grains down to submicron sizes can be possibly identified by such a variety of collectors; the presence of very low density collectors, like the foams and silica aerogels, should permit the collection of grains least modified, one of the primary goals of this investigation. This paper refers to the description of the instrument and of the various experiments. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Inst Astrophys Spatiale, F-91405 Orsay, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Mare Crisium, Freshwater PO40 9EP, England. Univ Kent, Unit Space Sci, Canterbury CT2 7NR, Kent, England. T&M Engn, Cape Canaveral, FL 32920 USA. ONERA, CERT DERTS, F-31055 Toulouse, France. SETI Inst, Moffett Field, CA 94035 USA. RP Bibring, JP (reprint author), Inst Astrophys Spatiale, Batiment 121,Campus, F-91405 Orsay, France. NR 9 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043305-7 J9 ADV SPACE RES PY 1997 VL 20 IS 8 BP 1477 EP 1480 DI 10.1016/S0273-1177(97)00420-1 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK38J UT WOS:000071955300011 ER PT S AU Grieve, RAF Cintala, MJ AF Grieve, RAF Cintala, MJ BE McDonnell, JAM Spohn, T Mohlmann, D Klinger, J TI Planetary differences in impact melting SO HYPERVELOCITY IMPACTS IN SPACE AND PLANETOLOGY SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO.8, BO.3 and BO.5 Symposium of COSPAR Scientific Commission B on Hypervelocity Impacts in Space and Planetology, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, Int Union Geodesy & Geophys, European Space Agcy, European Geophys Soc ID CRATERING MECHANICS; VENUS; METAMORPHISM; RECORD AB Surface gravity is a major variable in determining crater dimensions in impact events but it is not a factor in impact melting. This leads to differential scaling between crater and melt dimensions. The extent and effects of differential scaling are examined through model calculations and compared, where possible, with observational data Compared to smaller impacts on the same planet, relatively more melt is produced in larger impact events and this melt is relatively free of lithic clasts, hotter and less viscous. There are also differences between impacts resulting in similar-sized craters on planetary bodies of differing surface gravity. The absence of central peaks and the appearance of rings at smaller diameters in venusian and terrestrial, compared to lunar, complex impact craters may be due to weakening of uplifted transient cavity floor materials by impact melting. Some other examples of second-order differences in craters between these bodies due to differences in impact melting include the possibility that major impacts on the early Earth (and Venus) did not result in classic multiring craterforms, as observed on the moon. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Geol Survey Canada, Ottawa, ON K1A 0Y3, Canada. NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Grieve, RAF (reprint author), Geol Survey Canada, Ottawa, ON K1A 0Y3, Canada. NR 38 TC 23 Z9 24 U1 1 U2 5 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043305-7 J9 ADV SPACE RES PY 1997 VL 20 IS 8 BP 1551 EP 1560 DI 10.1016/S0273-1177(97)00877-6 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK38J UT WOS:000071955300026 ER PT B AU Piascik, RS Willard, SA AF Piascik, RS Willard, SA BE Cook, R Poole, P TI The characteristics of multi-site fatigue damage in the fuselage riveted lap splice joint SO ICAF 97: FATIGUE IN NEW AND AGEING AIRCRAFT, VOLS I AND II: VOL I: LECTURE PAPERS, VOL II: POSTER PAPERS LA English DT Proceedings Paper CT 19th Symposium of the International-Committee-on-Aeronautical-Fatigue - Fatigue in New and Ageing Aircraft (ICAF 97) CY JUN 18-20, 1997 CL EDINBURGH, SCOTLAND SP Int Comm Aeronaut Fatigue AB Destructive examinations were performed to document the progression of multi-site damage (MSD) in a four bay riveted lap joint removed from a full scale fuselage test article that was tested to 60,000 full pressurization cycles. Upper rivet row outer skin fatigue cracks initiated by a faying surface fretting damage mechanism, grew to lengths equivalent to 2 or 3 skin thicknesses before penetrating the outer skin surface, and propagated until link-up between rivet holes occurred. Fractography was used to characterize the growth of fatigue cracks ranging from 100 mu m to 5 mm in length. Results show that fatigue cracks emanating from fuselage lap splice rivet holes grow at similar rates and are predicted by fracture mechanics based methods. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Piascik, RS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 20 TC 1 Z9 1 U1 0 U2 0 PU ENGINEERING MATERIALS ADVISORY SERVICES LTD PI SHEFFIELD PA C/O NCODE, 230 WOODBOURN RD, SHEFFIELD S9 3LQ, ENGLAND BN 0-947817-97-2 PY 1997 BP 93 EP 114 PG 22 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BN07N UT WOS:000080598500005 ER PT B AU Harris, CE Coats, TW AF Harris, CE Coats, TW BE Cook, R Poole, P TI Analytical predictions of the residual strength of graphite fiber-reinforced laminated composites SO ICAF 97: FATIGUE IN NEW AND AGEING AIRCRAFT, VOLS I AND II: VOL I: LECTURE PAPERS, VOL II: POSTER PAPERS LA English DT Proceedings Paper CT 19th Symposium of the International-Committee-on-Aeronautical-Fatigue - Fatigue in New and Ageing Aircraft (ICAF 97) CY JUN 18-20, 1997 CL EDINBURGH, SCOTLAND SP Int Comm Aeronaut Fatigue ID THERMOMECHANICAL CONSTITUTIVE THEORY; PROGRESSIVE DAMAGE MODEL; STRESS-CONCENTRATIONS; MACROSCOPIC FRACTURE; ELASTIC COMPOSITES; DISTRIBUTED DAMAGE; MECHANICS AB Analytical predictions and experimental results are presented in this paper which experimentally verify the application of the progressive damage model developed by the authors to predict the residual strength of graphite-reinforced laminated composites. The investigation included laminates of IM7/5260 graphite/bismaleimide, AS4/3501-6 and AS4/93X graphite/epoxy, and AS4/APC-2 graphite/polyetheretherketone with several laminate stacking sequences. Test specimen geometries included unnotched, open-holes at several diameters, and crack-like thin-slit notches at several lengths. The progressive damage model, which has been implemented into a finite element structural analysis code, was used to predict the residual strength of the various test specimens due to quasistatic, monotonic tensile loading. The model predictions were in good agreement to the experimental results. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Harris, CE (reprint author), NASA, Langley Res Ctr, Mail Stop 188M, Hampton, VA 23681 USA. NR 41 TC 0 Z9 0 U1 0 U2 0 PU ENGINEERING MATERIALS ADVISORY SERVICES LTD PI SHEFFIELD PA C/O NCODE, 230 WOODBOURN RD, SHEFFIELD S9 3LQ, ENGLAND BN 0-947817-97-2 PY 1997 BP 267 EP 286 PG 20 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BN07N UT WOS:000080598500015 ER PT B AU Newman, JC Harris, CE James, MA Shivakumar, KN AF Newman, JC Harris, CE James, MA Shivakumar, KN BE Cook, R Poole, P TI Fatigue-life prediction of riveted lap-splice joints using small-crack theory SO ICAF 97: FATIGUE IN NEW AND AGEING AIRCRAFT, VOLS I AND II: VOL I: LECTURE PAPERS, VOL II: POSTER PAPERS LA English DT Proceedings Paper CT 19th Symposium of the International-Committee-on-Aeronautical-Fatigue - Fatigue in New and Ageing Aircraft (ICAF 97) CY JUN 18-20, 1997 CL EDINBURGH, SCOTLAND SP Int Comm Aeronaut Fatigue AB Widespread fatigue damage (WFD) in aging aircraft is a potential threat to structural integrity because fatigue cracks may greatly reduce residual strength. The purpose of this study was to develop, and verify with existing test data, the fatigue-crack initiation methodology required to predict the onset of WFD. Stress analyses of riveted single lap-splice joints were conducted using two- and three-dimensional elastic/elastic-plastic finite-element analyses including the influence of rivet interference. Using these analyses and small-crack theory, fatigue analyses were conducted on these joints. Predicted fatigue fives were compared to results from a comprehensive test program. These comparisons provided an assessment of the capability to analytically predict fatigue lives of riveted lap-splice joints based solely on crack propagation using small-crack theory. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 24 TC 1 Z9 1 U1 0 U2 0 PU ENGINEERING MATERIALS ADVISORY SERVICES LTD PI SHEFFIELD PA C/O NCODE, 230 WOODBOURN RD, SHEFFIELD S9 3LQ, ENGLAND BN 0-947817-97-2 PY 1997 BP 523 EP 552 PG 30 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BN07N UT WOS:000080598500028 ER PT B AU Starnes, JH Rose, CA Young, RD Rankin, CC AF Starnes, JH Rose, CA Young, RD Rankin, CC BE Cook, R Poole, P TI Effects of combined loads on the nonlinear response of stiffened shells with long cracks SO ICAF 97: FATIGUE IN NEW AND AGEING AIRCRAFT, VOLS I AND II: VOL I: LECTURE PAPERS, VOL II: POSTER PAPERS LA English DT Proceedings Paper CT 19th Symposium of the International-Committee-on-Aeronautical-Fatigue - Fatigue in New and Ageing Aircraft (ICAF 97) CY JUN 18-20, 1997 CL EDINBURGH, SCOTLAND SP Int Comm Aeronaut Fatigue AB The results of an analytical study of the nonlinear response of stiffened fuselage shells with long cracks are presented. The shells are modeled with a hierarchical modeling strategy and analyzed with a nonlinear shell analysis code that maintains the shell in a nonlinear equilibrium state while the crack is grown. The analysis accurately accounts for global and local structural response phenomena. Results are presented for various combinations of internal pressure and mechanical loads, and the effects of crack orientation on the shell response are described. The effects of combined loading conditions and the effects of varying structural parameters on the stress-intensity factors associated with a crack are presented. The dynamic amplification of the stress-intensity factors associated with the transient response of a suddenly broken fail-safe strap is also described. C1 NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23665 USA. RP Starnes, JH (reprint author), NASA, Langley Res Ctr, Struct Mech Branch, Hampton, VA 23665 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ENGINEERING MATERIALS ADVISORY SERVICES LTD PI SHEFFIELD PA C/O NCODE, 230 WOODBOURN RD, SHEFFIELD S9 3LQ, ENGLAND BN 0-947817-97-2 PY 1997 BP 967 EP 978 PG 12 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BN07N UT WOS:000080598500059 ER PT J AU Duxbury, NS Brown, RH AF Duxbury, NS Brown, RH TI The role of an internal heat source for the eruptive plumes on triton SO ICARUS LA English DT Article ID INFINITE PRANDTL NUMBER; GEYSER-LIKE PLUMES; THERMAL-CONVECTION; PHASE-COMPOSITION; NITROGEN ICE; TEMPERATURE; TRANSPORT; VISCOSITY; ATMOSPHERE; SURFACE AB For the first time the role of the internal heat source, due to radioactive decay in Triton's core, is investigated with respect to geyser-like plumes. Triton is one of only three known objects in the Solar System (the other two are Earth and the jovian satellite Io) where eruptive activity has been definitely observed. A new mechanism of energy supply to the Tritonian eruptive plumes is proposed. This mechanism is based on heat transport in the solid-nitrogen polar caps due to thermal convection, in addition to conduction. The conductive-convective model shows that a 1 K increase in the N-2 ice subsurface temperature over the surface value is reached much closer to the surface in the region of an upwelling subsurface plume compared with a pure conductive case. This temperature rise is sufficient to double the nitrogen vapor pressure. Therefore, it is enough to drive the atmospheric plumes to the observed height of approximate to 8 km, provided 1 K warmer nitrogen ice encounters a vent and hence is exposed to the approximate to 15-mu bar Tritonian atmosphere. Solid-state convection onsets if a nitrogen layer is sufficiently thick and the average solid N-2 grain size is small enough. Critical values of these parameters are presented for Triton. A possible origin of the subsurface vents on Triton is also suggested. (C) 1997 Academic Press RP Duxbury, NS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STN 183-501,PASADENA,CA 91109, USA. NR 43 TC 11 Z9 11 U1 1 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 1997 VL 125 IS 1 BP 83 EP 93 DI 10.1006/icar.1996.5554 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WE897 UT WOS:A1997WE89700008 ER PT J AU Bezard, B Griffith, CA Kelly, DM Lacy, JH Greathouse, T Orton, G AF Bezard, B Griffith, CA Kelly, DM Lacy, JH Greathouse, T Orton, G TI Thermal infrared imaging spectroscopy of Shoemaker-Levy 9 impact sites: Temperature and HCN retrievals SO ICARUS LA English DT Article ID COMET SHOEMAKER-LEVY-9; JUPITER; COLLISION; STRATOSPHERE; ATMOSPHERE; ABUNDANCES; ABSORPTION; TELESCOPE; METHANE; H-2 AB We present high-resolution 8-14 mu m observations of Shoemaker-levy 9 sites conducted on July 20, 30, and 31 1994 UT at the NASA Infrared Telescope Facility. Stratospheric heating was detected from strong enhancements of methane emission near 8.1 mu m over areas at least 15,000 km wide around the K site observed 23 hr after impact and around the L site 11 hr after impact. The intensity distribution between strong and weaker CH4 lines implies that the stratospheric heating was primarily confined to pressures less than 500 mu bar. The L site temperature increased by 80 +/- 10 K at 5 mu bar, but did not exceed 20 K around 1 mbar or 10 K around 10 mbar. The older K site was still 30 +/- 5 K warmer than the surroundings at the 10-mu bar level. The excess thermal energy stored in the upper jovian stratosphere was 3(-1.5)(+3) x 10(26) erg over the L site, and 2(-1)(+2) x 10(26) erg over the K site at the time of the observations. Comparison with numerical simulations indicates that a large fraction (>20%) of the kinetic energy of the L plume was transferred to the jovian atmosphere and not immediately radiated away. Acetylene line emission near 13.4 mu m was enhanced over an area similar to 18,000 km wide centered on the E site 2.6 days after impact. Radiative transfer models of this emission indicate temperatures 37 +/- 7 K higher than nominal around 3 mu bar. No such enhancement was seen in CH, spectral images, implying that the temperature perturbation did not significantly extend below the similar to 20-mu bar level. The H site observed simultaneously was 12 +/- 5 K warmer than the surroundings 1.4 day after impact. C2H2 lines were still slightly more intense over the K + W and Q1 sites on July 30 and 31, 8 to 10 days after impact. These observations can be interpreted either by temperature differences of about 13 and 10 K respectively in the 3-mu bar region, or by an increase in the C2H2 column density of 2.5-5 x 10(17) molecule cm(-2). Emission from hydrogen cyanide lines around 13.4 mu m was detected over all sites observed, The mass of HCN is about 2 x 10(12) g for the biggest plumes (K, L, G), 0.95 +/- 0.5 x 10(12) g over the E site, and 0.45 +/- 0.2 x 10(12) g over the H site, The total mass of HCN produced by all fragments is estimated to be 1.1 +/- 0.4 x 10(13) g. A consistent interpretation of the different pieces of information available suggests that the H plume was richer in dust than the E or A plume. (C) 1997 Academic Press C1 NO ARIZONA UNIV,DEPT PHYS & ASTRON,FLAGSTAFF,AZ 86011. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Bezard, B (reprint author), OBSERV PARIS,DEPT RECH SPATIALE,F-92195 MEUDON,FRANCE. NR 42 TC 30 Z9 30 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 1997 VL 125 IS 1 BP 94 EP 120 DI 10.1006/icar.1996.5610 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WE897 UT WOS:A1997WE89700009 ER PT B AU Million, S Hinedi, S AF Million, S Hinedi, S GP IEEE TI Tracking performance of the soft digital data transition tracking loop SO ICC'97: 1997 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS - TOWARDS THE KNOWLEDGE MILLENNIUM, CONFERENCE RECORD - VOLS 1-3 LA English DT Proceedings Paper CT 1997 IEEE International Conference on Communications - Towards the Knowledge Millennium (ICC 97) CY JUN 08-12, 1997 CL MONTREAL, CANADA SP IEEE Commun Soc AB This paper evaluates the steady-state tracking performance of the soft DTTL symbol synchronizer which is a low SNR approximation of the hyperbolic tangent nonlinearity in the in-phase channel. The normalized a-curve, slope of the a-curve, and normalized noise density are derived and compared to the hard DTTL which is a high SNR approximation of the nonlinearity. Moreover, the symbol SNR region where the steady-state timing jitter of the soft DTTL outperforms that of the hard DTTL is determined. RP Million, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 238-343,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3926-6 PY 1997 BP 26 EP 29 PG 4 WC Telecommunications SC Telecommunications GA BJ13Y UT WOS:A1997BJ13Y00006 ER PT B AU Lo, VY AF Lo, VY GP IEEE TI Characterization and simulation of end-to-end data link performance of the NASA deep space network SO ICC'97: 1997 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS - TOWARDS THE KNOWLEDGE MILLENNIUM, CONFERENCE RECORD - VOLS 1-3 LA English DT Proceedings Paper CT 1997 IEEE International Conference on Communications - Towards the Knowledge Millennium (ICC 97) CY JUN 08-12, 1997 CL MONTREAL, CANADA SP IEEE Commun Soc AB This paper contains an end-to-end performance characterization of subsystems which are used in both acquisition and data delivery of the NASA deep space network (DSN). Signal Processing WorkSystem (SPW) simulation runs are conducted to gain insight into the dynamics of the front-end subsystem signal acquisition. Comparisons are made among the mathematical acquisition models, the simulation results and the actual Mars Global Surveyer (MGS) emergency mode test data. The test shows that at high symbol signal-to-noise pow er ratio (SSNR>3dB), the measured end-re-end acquisition time is about 12 minutes. This result marches the prediction by the end-to-end link model and by the simulation. RP Lo, VY (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 161-241,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3926-6 PY 1997 BP 152 EP 158 PG 7 WC Telecommunications SC Telecommunications GA BJ13Y UT WOS:A1997BJ13Y00031 ER PT B AU Budinger, JM Fujikawa, G Kunath, RR Nguyen, NT Romanofsky, RR Spence, RL AF Budinger, JM Fujikawa, G Kunath, RR Nguyen, NT Romanofsky, RR Spence, RL GP IEEE TI Direct data distribution from low-Earth orbit SO ICC'97: 1997 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS - TOWARDS THE KNOWLEDGE MILLENNIUM, CONFERENCE RECORD - VOLS 1-3 LA English DT Proceedings Paper CT 1997 IEEE International Conference on Communications - Towards the Knowledge Millennium (ICC 97) CY JUN 08-12, 1997 CL MONTREAL, CANADA SP IEEE Commun Soc AB NASA Lewis Research Center (LeRC) is developing the space and ground segment technologies necessary to demonstrate a direct data distribution (D-3) system for use in space-to-ground communication links from spacecraft in low-Earth orbit (LEG) to strategically located tracking ground terminals. The key space segment. technologies include a K-band (19 GHz) MMIC-based transmit phased array antenna, and a multichannel bandwidth- and power-efficient digital encoder/modulator with an aggregate data rate of 622 Mb/s. Along with small (1.8 meter), low-cost tracking terminals on the ground, the D-3 system enables affordable distribution of data to the end user or archive facility through interoperability with commercial terrestrial telecommunications networks. The D-3 system is applicable to both government and commercial science and communications spacecraft in LEO. The features and benefits of the D-3 system concept are described. Starting with typical orbital characteristics, a set of baseline requirements for representative applications is developed including requirements for onboard storage and tracking terminals, and sample link budgets are presented. Characteristics of the transmit array antenna and digital encoder/modulator are described. The architecture and components of the tracking terminal are described, including technologies for the next generation terminal. Candidate flights of opportunity for risk mitigation and space demonstration of the D-3 features are identified. RP Budinger, JM (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3926-6 PY 1997 BP 662 EP 673 PG 12 WC Telecommunications SC Telecommunications GA BJ13Y UT WOS:A1997BJ13Y00127 ER PT B AU Popernack, TG Owens, LR Hamner, MP Morris, MJ AF Popernack, TG Owens, LR Hamner, MP Morris, MJ BE Owen, FK TI Application of temperature sensitive paint for detection of boundary layer transition SO ICIASF '97 RECORD - INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES LA English DT Proceedings Paper CT 17th International Congress on Instrumentation in Aerospace Simulation Facilities CY SEP 29-OCT 02, 1997 CL ASILOMAR CONF CTR, PACIFIC GROVE, CA SP Naval Postgrad Sch, Complere Inc HO ASILOMAR CONF CTR AB Temperature sensitive paint systems exploit the variation in convective heat transfer associated with changes from laminar to turbulent flow for detection of boundary layer transition. For this detection technique, it is important for wind tunnel models to have slow thermal response relative to convection heat transfer. Wind tunnels that can produce rapid changes in freestream temperature can create a model thermal response allowing temperature sensitive paint to indicate transition. Numerical heat transfer simulations provide acceptable estimates to assess test techniques and model thermal characteristics, Data are presented to substantiate that the desired test condition could be achieved for a period of time sufficient to document the boundary layer state. RP Popernack, TG (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 2 Z9 2 U1 0 U2 2 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4168-6 PY 1997 BP 77 EP 83 DI 10.1109/ICIASF.1997.644666 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BJ90A UT WOS:A1997BJ90A00009 ER PT B AU Chandrasekhara, MS Carr, LW Wilder, MC Paulson, GN Sticht, CD AF Chandrasekhara, MS Carr, LW Wilder, MC Paulson, GN Sticht, CD BE Owen, FK TI Design and development of a dynamically deforming leading edge airfoil for unsteady flow control SO ICIASF '97 RECORD - INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES LA English DT Proceedings Paper CT 17th International Congress on Instrumentation in Aerospace Simulation Facilities CY SEP 29-OCT 02, 1997 CL ASILOMAR CONF CTR, PACIFIC GROVE, CA SP Naval Postgrad Sch, Complere Inc HO ASILOMAR CONF CTR AB A novel approach to unsteady flow separation and dynamic stall control using a dynamically deforming leading edge airfoil is described. The design details of a carbon-fiber composite skin airfoil having a thickness of 0.002 in at the leading edge and capable of deforming at 20 Hz in unsteady flow at freestream Mach numbers of up to 0.45, are discussed. Implementation of the scheme at model scales places extraordinary demands on the design, material and fabrication of such an airfoil. Rate scaling further requires very-rapid-response instrumentation, measurement techniques and data acquisition schemes. The special instrumentation control system developed for these experiments as well as the fluid dynamic results of successful flow control that was achieved using this method, are also discussed. RP Chandrasekhara, MS (reprint author), USN,POSTGRAD SCH,DEPT AERONAUT & ASTRONAUT,NASA,JOINT INST AERONAUT,MONTEREY,CA 93943, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4168-6 PY 1997 BP 132 EP 140 DI 10.1109/ICIASF.1997.644673 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BJ90A UT WOS:A1997BJ90A00014 ER PT B AU Tuma, ML Elam, KA Sawatari, T Gaubis, P Lin, YP AF Tuma, ML Elam, KA Sawatari, T Gaubis, P Lin, YP BE Owen, FK TI Fabry-Perot photonic temperature sensor system SO ICIASF '97 RECORD - INTERNATIONAL CONGRESS ON INSTRUMENTATION IN AEROSPACE SIMULATION FACILITIES LA English DT Proceedings Paper CT 17th International Congress on Instrumentation in Aerospace Simulation Facilities CY SEP 29-OCT 02, 1997 CL ASILOMAR CONF CTR, PACIFIC GROVE, CA SP Naval Postgrad Sch, Complere Inc HO ASILOMAR CONF CTR AB In order to monitor aircraft engine performance, there is a need for a sensor which can accurately measure temperature from -50 degrees C to 600 degrees C in an aircraft environment. The objective of the development and testing of this prototype sensor system was to determine the feasibility of operating an optical sensor in such a hostile environment. In this work a photonic sensor was utilized to monitor the exhaust gas temperature (EGT) of an OV-10D aircraft engine. The sensor has successfully flown over 50 hours and proven to be immune to source fluctuations, surface deterioration of the optical element (located inside the sensor head), and able to withstand and operate in normal flight conditions as well as sustained severe flight conditions with forces exceeding 4 g's. Potential commercial uses for this sensor include monitoring temperature for aeropropulsion system control, military vehicle and naval engine control, conventional and nuclear power plant monitoring, and industrial plant monitoring. RP Tuma, ML (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4168-6 PY 1997 BP 369 EP 377 DI 10.1109/ICIASF.1997.644755 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BJ90A UT WOS:A1997BJ90A00039 ER PT B AU Perrone, D Di Stefano, S AF Perrone, D Di Stefano, S GP AMER INST CHEM ENGINEERS TI Survey of lithium - Ion battery performance for potential use in NASA missions SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB This paper presents the initial results of an exploratory effort undertaken at JPL to establish the baseline electrical performance and cycle life envelope for commercially available lithium-ion cells. Sample cells were obtained from three manufacturers for evaluation. Testing consists of evaluating the charge and discharge characteristics at different temperatures and rates. Cycle life performance is being determined with both 40% and 100% depth of discharge regimes without the benefit of individual cell bypass circuitry during charge. Energy densities in excess of 100 watt-hours per kilogram and very promising cycle life performance have actually been demonstrated in some cases. It is expected that this technology will be of value for future NASA missions if it can be scaled up to the 20 ampere-hour level and particularly if cycle life comparable to that of nickel-cadmium or nickel-hydrogen can be demonstrated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Perrone, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 39 EP 41 PG 3 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900009 ER PT B AU Smart, MC Huang, CK Ratnakumar, BV Surampudi, S AF Smart, MC Huang, CK Ratnakumar, BV Surampudi, S GP AMER INST CHEM ENGINEERS TI Development of advanced lithium-ion rechargeable cells with improved low temperature performance SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Due to future plans to explore Mars and the outer planets, NASA has interest in developing lithium-ion rechargeable batteries that are capable of operating at low temperatures. To address these problems, we have initiated research focused upon the development of advanced electrolyte systems for lithium-ion cells with improved low temperature performance. Promising electrolyte solutions were selected based on conductivity and stability considerations and incorporated into C/LiCoO2 cells for evaluation. The discharge capacity and rate capability as a function of temperature were evaluated in two types of lithium-ion cells, consisting of graphite-based systems with EC-based electrolytes and coke-based systems with PC-based electrolytes. Some of the experimental lithium-ion cells fabricated with these electrolytes were found to be capable of operating at temperatures as low as -30 degrees C (both charging and discharging at -30 degrees C) and provide more than 55% of the room temperature capacity. Cycle life testing of the these cells at -20 degrees C and at room temperature is in progress. Some of the cells have completed more than 500 cycles to date (100% DOD). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 5 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 52 EP 57 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900012 ER PT B AU Deligiannis, F Frank, H Davies, E Russell, PG Reddy, TB AF Deligiannis, F Frank, H Davies, E Russell, PG Reddy, TB GP AMER INST CHEM ENGINEERS TI Ultra low temperature batteries for Martian applications SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Mars Microprobes are secondary payload on the 1998 Mars Surveyor Lander Mission. Two identical microprobes will be attached on the 1998 Mars Surveyor spacecraft that will be launched on a McDonnell Douglas Med-Lite in January 1999. After an 11-month journey to Mars the two probes will be released immediately after the 1998 Lander and cruise stage separate. The probes will use a self-orienting, non-ablative aeroshell for their single-stage passive entry, decent, and landing on Mars. The Microprobes will penetrate through the aeroshell and into the surface upon impact with a impact velocity approximately 200 m/sec. The impact site will be within 100 miles of the Martian south polar cap and about 120 miles from the 1998 Lander. During penetration, the probes will separate into two sections; a surface (aft-body) module and a subsurface (fore-body) module. The aft-body module will house the power source and the telecommunication subsystem. The fore-body will house most of the science instruments. The power source for the Microprobes will be two lithium primary batteries. The batteries will provide power for all the Microprobe instruments and data relays during all phases of the mission. The batteries will be designed to survive the peak landing shock that may reach 80,000 g and to withstand the stringent Martian surface temperatures (-80 degrees C). Primary lithium batteries were selected for the Microprobes based on the high specific energy and the promising low temperature performance. Modifications to existing lithium primary cells were made to develop a battery that met all requirements. This paper will describe the cell/battery design and will provide test results obtained during the various phases of development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deligiannis, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 72 EP 76 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900016 ER PT B AU Manzo, MA Hall, SW AF Manzo, MA Hall, SW GP AMER INST CHEM ENGINEERS TI Aerospace nickel-cadmium cell verification - An update SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Over the past twenty-five years NASA has successfully flown "NASA-Standard" nickel-cadmium (Ni-Cd) Cells manufactured by GE/Gates/SAFT on a variety of spacecraft. In 1992 a NASA Battery Review Board determined that the strategy of a NASA Standard Cell and Battery Specification and the accompanying NASA control of a standard manufacturing control document (MCD) for Ni-Cd cells and batteries was unwarranted. As a result of that determination, standards were abandoned and the use of cells other than the NASA standard became more accepted. In order to gain insight into the performance and characteristics of the various aerospace Ni-Cd products available, tasks were initiated within the NASA Aerospace Flight Battery Systems Program that involve the procurement and testing of representative aerospace Ni-Cd cell designs. A standard set of test conditions has been established in order to provide similar information about the products from various vendors. The objective of this testing is to provide independent verification of representative commercial flight cells available in the marketplace today. This paper will provide an update on the progress of verification tests being run on cells from the following manufacturers: Sanyo 35 Ampere-hour (Ah) standard and 35 Ah advanced Ni-Cd cells, SAFT 50 Ah Ni-Cd cells and 21 Ah Magnum and 21 Ah Super Ni-Cd-TM cells from Eagle Picher. A limited number of 18 Ah and 55 Ah cells from Acme Electric are also on test to provide an initial evaluation of the Acme aerospace cell designs. Additionally, 21, 35 Ah aerospace design Ni-MH cells from Sanyo are being evaluated under the standard conditions established for this program. To date, all cells have been received and have been fully characterized. Life tests are in progress on all of the cell packs. Data from this program will establish the performance characteristics of the cells produced by the various vendors. It will also provide baseline information for comparison with future cell lots. The design parameters for the cells being evaluated as part of this program, details of the verification test plan, and the test results available to date will be discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Manzo, MA (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,MS 309-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 99 EP 107 PG 9 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900021 ER PT B AU Britton, DL AF Britton, DL GP AMER INST CHEM ENGINEERS TI Development of lightweight nickel fiber electrodes for nickel-based systems SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Development of a high specific energy battery is the main goal of the lightweight nickel electrode program at the NASA Lewis Research Center. The approach has been to improve the nickel electrode by continuing combined inhouse and contract efforts to develop a more efficient and lighter weight electrode for nickel-hydrogen and nickel-metal hydride cells. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydroxide active material. Two of the fiber plaques used in this development program were developed by Memtec America Corporation and by Ribbon Technology Corporation. These plaques are new material products that have the advantage of an increased surface area available for the deposition of active material as well as an increase in the electrochemical accessibility to the active material. Initial tests include activation and capacity measurements at different discharge levels followed by half-cell cycle testing at 80 percent depth-of-discharge in a low-Earth-orbit regime. The electrodes that pass the initial tests are life cycle-tested in a boiler plate nickel-hydrogen cell before flightweight designs are built and tested. A grant with Auburn University to develop a high performance nickel hydroxide electrode utilizing composite micro-structure nickel fiber electrodes will also be described. NASA Lewis has contracted with Hughes Space and Communications Company to transfer the technology and commercially develop the lightweight nickel electrode. Encouraging performance of the small diameter nickel fiber electrode has been demonstrated and the goal of a 100 wh/kg cell appears feasible. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Britton, DL (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,MS 309-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 114 EP 119 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900023 ER PT B AU Di Stefano, S Perrone, D Ratnakumar, BV AF Di Stefano, S Perrone, D Ratnakumar, BV GP AMER INST CHEM ENGINEERS TI Characterization of nickel-hydrogen 2-cell common pressure vessels for NASA missions SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Cells from the flight lot of The Mars Global Surveyor (MGS) battery were configured as a test pack and underwent characterization tests. The MGS battery is based on 20 Ampere-hour 2-Cell Common Pressure Vessel (CPV) technology. The primary goal of the current CPV characterization test was to understand how (NiH2) V/T curves would map onto the NiCd curves existing in spacecraft hardware. To that end, (NiH2) V/T curves were experimentally determined. The results of that determination are described below. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Di Stefano, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 154 EP 158 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900031 ER PT B AU Rao, GM Armantrout, JD Hafen, DP Brown, RA AF Rao, GM Armantrout, JD Hafen, DP Brown, RA GP AMER INST CHEM ENGINEERS TI Voltage vs temperature characterization of standard 80Ah Eagle-Picher NiH2 cells SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The electrical and thermal performance of 22 common or standard 80 Ah individual pressure vessel (IPV) Nickel-Hydrogen (NiH2) cells manufactured with slurry process electrodes and three cycled dry sinter process electrode cells similar to those used on the Hubble Space Telescope (HST) Battery have been acceptance tested and characterized over a matrix of operating conditions from 14 degrees F to 86 degrees F. The testing included standard capacity tests and electrical cycling using 96-minute cycling regimens incorporating constant depth of discharge (DOD) cycles with step changes in cell current at two points in the discharge. The testing was performed in both a test cart and an environmental chamber, with some of the cycling repeated under isothermal conditions. The results of the testing included cyclic heat generation during a typical 96-minute cycle, operating capacity data vs. cutoff voltage To generate a temperature-compensated voltage curve, and voltage characteristics suitable to develop a voltage prediction model. Four additional cells were subjected to electrical cycling within an environmental chamber for the purpose of acquiring cyclic heat generation data as a function of state-of-charge, temperature and charge/discharge rate. The testing in the environmental chamber included conditioning cycles and characterization cycles at various load conditions. The voltage characteristics for matrix conditions tested within the chamber matched those obtained for the corresponding testing within the test cart. C1 NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20777 USA. RP Rao, GM (reprint author), NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20777 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 159 EP 173 PG 15 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900032 ER PT B AU Timmerman, P Bugga, R AF Timmerman, P Bugga, R GP AMER INST CHEM ENGINEERS TI Reconditioning mechanism for nickel-hydrogen batteries SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB This paper provides a detailed discussion of the mechanism of reconditioning for nickel-hydrogen batteries. It gives the chemistry of the various phases of hydrated nickel oxides, and details their differences. The interaction of cell design, operational parameters, and performance are described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91104 USA. RP Timmerman, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91104 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 198 EP 200 PG 3 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900037 ER PT B AU Lowery, JE Brewer, JC Whitt, TH Jackson, LG AF Lowery, JE Brewer, JC Whitt, TH Jackson, LG GP AMER INST CHEM ENGINEERS TI AXAF-I electrical power system breadboard simulation testing SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Electrical Power System (EPS) breadboard simulation testing for the Advanced X-ray Astrophysics Facility-Imaging (AXAF-I) spacecraft is being performed at NASA's Marshall Space Flight Center(MSFC). This real-time testing will verify functionality of software control routines and where possible, operation of flight type hardware. The breadboard completely encompasses the AXAF-I EPS allowing contingency simulation and planning. The planned cycling operation of the breadboard will provide a real-time orbital cycle lead over the flight vehicle and hopefully identify any chronologically induced anomalies while sufficient time remains to take corrective action or make preventative moves on the flight vehicle. The breadboard system will also offer a platform for analysis of the EPS of the flight vehicle to investigate the source of anomalies observed during flight. The AXAF-I EPS testbed utilizes three Nickel-Hydrogen (NiH2) batteries composed of cells from the same build lot as the cells in the batteries on the flight vehicle. Operation of the breadboard EPS with the flight type NiH2 batteries is scheduled to begin early June 1997; the launch of the AXAF-I spacecraft is scheduled for summer 1998. This paper will discuss the design and assembly of the AXAF-I EPS breadboard testbed with an emphasis on the design and performance of the NiH2 batteries. Future papers will report on ongoing testing and performance from the AXAF-I EPS breadboard testbed. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Lowery, JE (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 219 EP 223 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900041 ER PT B AU Hoberecht, MA Green, RD AF Hoberecht, MA Green, RD GP AMER INST CHEM ENGINEERS TI Use of excess solar array power by Regenerative Fuel Cell energy storage systems in low Earth orbit SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Regenerative Fuel Cells (RFC's) are a competing energy storage system technology for a number of low-earth-orbit applications. The system is comprised of an electrolyzer which utilizes solar array power to convert water into hydrogen and oxygen reactants, a fuel cell that recombines the reactants back into water and produces power during eclipse, and associated controls and reactant storage. Round-trip electrical efficiencies of RFC systems are typically lower than competing battery energy storage systems. This results in larger solar arrays for the same application, with inherent drag, mass, and cost penalties. However, the increase in solar array size can be limited, if not totally eliminated, because of the ability of RFC systems to use excess solar array power. With a RFC system, any excess solar array power can be converted directly into reactants. In some cases the quantity of reactants can be significant. This is in addition to the normal quantity of reactants produced during the insolation (sunlit) portion of a typical orbital cycle. Assuming sufficiently sized reactant storage tanks, the additional reactants can be used to reduce the required input power for all orbital cycles throughout the year, effectively reducing the required size of the solar array. With battery energy storage systems, excess solar array power is typically shunted and not utilized. For this paper, the International Space Station (ISS) application was chosen for evaluation and comparison of battery and REC energy storage systems. This selection was based on the authors' familiarity with the ISS design and the availability of a detailed in-house computer model specific to the ISS electrical power system (SPACE). Combined altitude and orientation effects, seasonal variations, and beginning-of-life solar array performance were examined for individual orbits at and above specified reference points. Charging characteristics of the battery system were also investigated. The evaluation allowed a comparison of the solar array size required with the existing battery energy storage system to the projected solar array size required with a possible RFC system. The results of the examination indicated that no increase in solar array size would be necessary for the ISS if outfitted with a RFC energy storage system, in spite of the lower round-trip electrical efficiency. For orbits with a minimum of excess power, the battery energy storage system used only 73% of the available solar array power as compared to 100% usage for a RFC system. The usage by the battery system was far less for the orbits with higher amounts of excess power. In terms of solar array size, a 59% efficient RFC system thus becomes equivalent to an 80% efficient battery system. Thus, for the ISS and possibly other low-earth-orbit spacecraft, there would be little if any solar array size advantage as a result of a difference in round-trip electrical efficiency between battery and RFC energy storage systems. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hoberecht, MA (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 224 EP 227 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900042 ER PT B AU Warshay, M Prokopius, P Le, M Voecks, G AF Warshay, M Prokopius, P Le, M Voecks, G GP AMER INST CHEM ENGINEERS TI The NASA fuel cell upgrade program for the Space Shuttle Orbiter SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB As part of NASA's overall efforts to improve the Space Shuttle operations, a program to upgrade the existing fuel cell powerplant has begun. The upgrade will involve replacing the alkaline fuel cell (AFC) system with a proton exchange membrane (PEM) fuel cell system, resulting in a much lower life cycle cost of the powerplant. The program is being implemented by a team comprised of NASA/JSC, NASA/LeRC, and JPL personnel, with support from NASA/KSC. With extremely high annual maintenance costs ($12M-$19M per year) and subsystem replacement costs (which had recently been costing $28.5M per shipset per year), the need for a lower cost Orbiter fuel cell powerplant is obvious. Earlier NASA plans to upgrade the shuttle fuel cell were not adequately funded and only focused upon upgrading the existing AFC. For the current program, the PEM fuel cell system will be implemented because the projected long life (10,000 hrs. vs. 2,000 hrs. for AFC), high power density (PEM projected to produce 50% more power), and enhanced system reliability and safety all lead to significantly lower life cycle powerplant costs. And in addition to the Orbiter application, PEM fuel cell development would support a number of important space applications that the AFC would not, such as Lunar/Mars transportation, the Reusable Launch Vehicle (RLV), Space Station emergency power and/or future energy storage applications, and various portable applications. NASA is also leveraging all of the large scale PEM fuel cell development activities that are ongoing for DOE, DOD, and commercial applications. There is no activity in the AFC area. The Shuttle Fuel Cell Upgrade plan of the JSC/LeRC/JPL team includes the following key elements: 1) Systems Analyses to assure compatibility/maximum utilization by shuttle of the best PEM fuel cell characteristics; 2) Short Stack Testing of the leading PEM fuel cell contractors' hardware; 3) Detailed Task Objective (DTO) Flight Experiment to verify PEM system water management and thermal management under zero-g operation; 4) A Downselect to the best PEM system; and 5) Development of the Flight Hardware Powerplant system, including, of course both the power and accessory subsystems. The planned success-oriented, four year effort is a coherent program to develop a 20 kW PEM fuel cell powerplant. The current major program tasks under way are Short Stack Testing, and Systems Analyses. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Warshay, M (reprint author), NASA, Lewis Res Ctr, Mail Stop 301-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 228 EP 231 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900043 ER PT B AU Keys, DJ Ho, R Scolese, CJ Wingard, RB Tasca, DM Bortulin, MJ Ferrara, AA Longcoy, DF AF Keys, DJ Ho, R Scolese, CJ Wingard, RB Tasca, DM Bortulin, MJ Ferrara, AA Longcoy, DF GP AMER INST CHEM ENGINEERS TI Transient effects during 120 VDC spacecraft high voltage dc fuse clearing SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Historically, spacecraft power system nominal bus voltages have been increasing over time to accommodate increasing bus load demands while reducing spacecraft mass, particularly in electrical harnesses. The use of higher nominal spacecraft bus voltages requires higher rated circuit protection devices as well as a thorough understanding of power system dynamics during fault clearing events. Understanding the power system dynamics is also a necessity in the design phase for operation and survival of all electrical components and spacecraft instruments that may be exposed to high voltage induced transients. The Earth Observing System (EOS) AM-1 spacecraft, being built for the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center by Lockheed Martin Missiles & Space, utilizes a tightly regulated 120 volt de primary bus architecture and predominantly relies on fuses to provide power system bus protection. During the design phase of the program, and subsequent development of susceptibility requirements for spacecraft component testing, extensive SPICE modeling efforts were undertaken to evaluate system voltage transient effects under various fault clearing conditions. Detailed analysis and subsequent testing produced an accurate model of behavior for a typical power system feed during fuse clearing events. This paper presents details of the EOS AM-1 power subsystem topology, which is a single point ground 120 VDC +/-4% regulated power system, correlation of the power system analytical modeling and subsequent testing of actual fuse blow transients, as well as covering the power subsystem test configuration that was developed to simulate the actual EOS AM-I spacecraft bus topology. The analytical modeling and test configuration presented in the paper will focus on transient voltage response for 120 VDC line-to-ground and line-to-return fault clearing events involving Mepcopal P600L-135 series 5 and 10 ampere rated fuses and various power cable lengths consisting of shielded 5 and 7 wire AWG #20 wires. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Keys, DJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 364 EP 369 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900069 ER PT B AU Carr, GA Franco, LA AF Carr, GA Franco, LA GP AMER INST CHEM ENGINEERS TI X2000 power system architecture SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB JPL is starting a new program that targets the exploration of the outer planets in our Solar System. The Advanced Deep Space System Development Program (ADSSDP) is to provide a spacecraft system for a series of missions exploring the outer planets. The first objective of the program is to provide an engineering model of the spacecraft system by the year 2000. The engineering model dubbed the X2000, is basis for the first series of missions. The program will continue to advance the "state of the art" in spacecraft system development with a new engineering model every three years to benefit the missions that follow. The X2000 power system must answer the challenge of an outer planets spacecraft by reducing its power, mass and volume envelope. Traditionally, there has been an increasing trend of the percentage of the power system electronics to the total spacecraft mass. With all of the previous technology focus on high-density digital packaging, the power system electronics has not been keeping pace forcing the spacecraft to take a major hit in the power system mass. New technology being developed and validated by the New Millennium Program will aid in the reduction of the power system allocation to meet the total spacecraft mass and volume budget. The new technology in MCM packaging and mixed signal ASICs increase the packaging density of the power system electronics allowing for the integration in to the spacecraft avionics package. Although new technology has improved the power electronics packaging density, a power system architecture is required that can reduce the requirements on the spacecraft loads. The architecture can reduce the number of power converters on the spacecraft by providing load specific voltages and by increasing capability in de-coupling loads. The architecture also needs the modularity to accommodate multiple missions while maintaining a low recurring cost. Although the focus has been on shrinking the power system volume and mass, the efficiency and functionality cannot be ignored. Increased efficiency and functionality will only enhance the power systems capability to reduce spacecraft power requirements. The combination of the New Millennium packaging technology with the X2000 power system architecture produces a product capable of meeting a wide range of mission requirements with a low system recurring cost. C1 CALTECH, Jet Prop Lab, Power Syst Engn Grp, Pasadena, CA 91109 USA. RP Carr, GA (reprint author), CALTECH, Jet Prop Lab, Power Syst Engn Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 381 EP 386 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900072 ER PT B AU Barry, RK AF Barry, RK GP AMER INST CHEM ENGINEERS TI Implementation and test of a partial array shunt system for two small explorer spacecraft SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB A power system which utilizes a partial array shunt has been designed and built for two new Small Explorer (SMEX) scientific satellites. The power system topology is significantly changed from earlier SMEX spacecraft which carried full array shunt systems. The first application of the new SMEX power system is for the Transition Region And Coronal Explorer (TRACE) mission. This new power system development included higher fidelity solar array hardware and software to allow integrated ground testing that more closely matches actual on-orbit operating modes. Also, existing airborne support equipment for use on the L1011 Pegasus launch platform has been modified to provide full spacecraft power system functional testing just prior to launch. The implementation and test of the new SMEX power system and associated electrical ground/airborne equipment for the TRACE mission will be presented in this paper. Results of functional tests on the TRACE spacecraft have demonstrated robust control stability of the new SMEX power system design under varying spacecraft power profiles and good fidelity in the new test system. C1 NASA, Space Power Applicat Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barry, RK (reprint author), NASA, Space Power Applicat Branch, Goddard Space Flight Ctr, Mail Code 723, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 387 EP 390 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900073 ER PT B AU Lewis, CR Phillips, WM Shields, VB Stella, PM Bekey, I AF Lewis, CR Phillips, WM Shields, VB Stella, PM Bekey, I GP AMER INST CHEM ENGINEERS TI Multi-bandgap high efficiency converter (RAINBOW) SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Many proposals have been made to increase solar array efficiency by using two or more cells with appropriately spaced bandgaps to span a greater portion of the incident spectrum. One such technique is to split the solar spectrum and focus each portion on a different cell bandgap. Each bandgap is selected to best match the input spectral portion and thus obtain maximum efficiency. This paper reports on the reexamination of the spectrally split, individually matched cell approach using modern-day optics and lightweight structures. The RAINBOW multi-bandgap system represents a unique combination of solar cells, concentrators and beam splitters. The use of separate cells offers the widest possible scope of material choices. Many different component combinations are possible. The relatively low temperature operation, due to reduced thermal input per cell, adds to the performance increase. Finally, RAINBOW is a flexible system which can readily expand as new high efficiency components are developed. Based to a large extent on data for real cells and optical components, RAINBOW is expected to convert over 40% of incident solar energy to electricity at the system level. This conclusion is based on preliminary analyses of cell and optics performances. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lewis, CR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 401 EP 406 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900076 ER PT B AU Jaworske, DA AF Jaworske, DA GP AMER INST CHEM ENGINEERS TI Reflectivity of silver and silver-coated substrates from 25 degrees C TO 800 degrees C SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB A bench top facility was used to evaluate the reflectivity of several candidate coating-substrate combinations in vacuum at elevated temperatures. Silver was selected as the reflective coating of choice, while copper, nickel, electroless nickel on copper, and 304 stainless steel were selected as substrates. Pure silver, with no coating at all, was also evaluated. An optically flat silver-coated sapphire substrate was used as a standard. All metal substrates were either metallurgically polished or diamond turned to a mirror finish prior to silver deposition. Silicon dioxide was used as a protective coating in most cases. Reflectivity measurements were made at room temperature in the visible range with a spectrophotometer, and at elevated temperatures up to 800 degrees C with a helium-neon laser at 632 nm. Results from the high temperature reflectivity measurements will be presented. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Jaworske, DA (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 407 EP 411 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900077 ER PT B AU Bailey, S Brinker, D Curtis, H Jenkins, P Scheiman, D AF Bailey, S Brinker, D Curtis, H Jenkins, P Scheiman, D GP AMER INST CHEM ENGINEERS TI Solar cell calibration and measurement techniques SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The increasing: complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WD15387, "Requirements for Measurement and Calibration Procedures for Space Solar Cells" was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and the international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Bailey, S (reprint author), NASA, Lewis Res Ctr, MS 302-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 412 EP 415 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900078 ER PT B AU Kerslake, TW Mason, LS Strumpf, HJ AF Kerslake, TW Mason, LS Strumpf, HJ GP AMER INST CHEM ENGINEERS TI High-flux, high-temperature thermal vacuum qualification testing of a solar receiver aperture shield SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LeRC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal multi-foil insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near equilibrium temperature of 2072 K was achieved. The aperture shield sustained no visible damage as a result of the exposures. This paper describes the aperture shield thermal-vacuum qualification test program including the test article, test facility, procedures, data collection, test success criteria, results and conclusions. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Kerslake, TW (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 440 EP 445 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900084 ER PT B AU Mason, LS Shaltens, RK Espinosa, WD AF Mason, LS Shaltens, RK Espinosa, WD GP AMER INST CHEM ENGINEERS TI Experimental data for two different alternator configurations in a solar brayton power system SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB A solar dynamic (SD) space power system has been under test at the NASA Lewis Research Center since 1994. The SD Ground Test Demonstration (GTD) system includes a solar concentrator, heat receiver with thermal energy storage, Brayton power conversion unit, and radiator installed in a thermal-vacuum chamber with a solar simulator. The Brayton unit has been operated with two different turboalternator-compressor (TAC) assemblies, one which included a Rice-Lundell alternator and another which incorporated a permanent magnet (PM) alternator. The Rice alternator was part of the mini-Brayton rotating unit, designed and built during the 1970's and refurbished for the GTD. The PM TAC was a development unit from the Joint US/Russian SD Flight Project. This paper highlights the operational differences (and similarities) between the Rice and PM TAC configurations including a comparative evaluation of startup characteristics and operating performance. The two alternator configurations were tested under similar thermal conditions, as an interchangeable component within the SD system. The electrical characteristics of the two units, however, dictated the use of significantly different power conditioning and control strategies. The electrical control architectures are described and compared. Test data are presented on TAC startup and system operating performance for both configurations. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Mason, LS (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 454 EP 459 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900086 ER PT B AU Mondt, JF Underwood, ML Nesmith, BJ AF Mondt, JF Underwood, ML Nesmith, BJ GP AMER INST CHEM ENGINEERS TI Future radioisotope power needs for missions to the solar system SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB NASA is no longer using single, large, highly instrumented spacecraft for space exploration. Instead NASA is identifying scientific information that is desired about our solar system and beyond and using multiple, small, low-cost spacecraft with small specific instruments to obtain that data These smaller, low-cost spacecraft require less power, have lower launch mass and thus require lower trajectory injection energy, thereby reducing launch costs. However, to enable such spacecraft to obtain the desired scientific data, NASA may be able to use a more efficient power source that is compatible with the lower launch and injection mass and the lower level of power demand. NASA is exploring many types of power source technologies. One discussed in this paper is a new high efficiency, low mass, energy converter to replace the present thermoelectric converter in the radioisotope thermoelectric generator (RTG). This new technology converter will allow the number of radioisotope-fueled heat sources and the mass to be reduced. NASA and DOE plan a cooperative team effort with industry, government laboratories and universities to develop a near term, low cost, low power, (100 watt electric class), low mass, (<10 kg), advanced radioisotope space power source (ARPS) and in the process reduce the plutonium-related costs as well. The near term is focused on developing an advanced energy converter to use with the General Purpose Heat Source (GPHS). The GPHS was developed and used for the current radioisotope thermoelectric generators (RTGs). Advanced energy converter technologies are needed as a more efficient replacement for the existing thermoelectric converters so that the space radioisotope power source mass and cost can be reduced. A more advanced technology space radioisotope power system program is also planned that addresses a longer-term need. Twenty first century robotic scientific information missions to the outer planets and beyond are planned to be accomplished with microspacecraft which may demand safe, even more compact, lower-power, lower-mass radioisotope power sources than those which can be achieved as a result of the near term efforts. The longer-term program focuses not only on converter technology but also on lower power, more compact radioisotope heat source technology and smaller, lower mass radioisotope heater units for second generation microspacecraft. This more ambitious, longer time-horizon focus necessarily occurs at this time on the technology R&D level rather than at the system technology level. NASA and DOE plan a cooperative team effort with Universities, Government Laboratories and Industry to develop technologies for a 100 milliwatt electric class radioisotope power source and a 10 watt electric class small radioisotope power source. This power source will be compatible with NASA's long term technology for low cost, low mass microspacecraft for the 21st century robotic space missions. This paper describes requirements for potential needs for three different sizes of space radioisotope power sources. All three must be safe, low cost, low mass and have short delivery schedules. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mondt, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 460 EP 464 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900087 ER PT B AU Borshchevsky, A Chmielewski, A Chen-Kuo, H Bass, J Bugby, D Pustovalov, A Gusev, V AF Borshchevsky, A Chmielewski, A Chen-Kuo, H Bass, J Bugby, D Pustovalov, A Gusev, V GP AMER INST CHEM ENGINEERS TI Powerstick development SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB A device called a Powerstick is being developed to satisfy the requirements of several potential solar system exploration missions. The Powerstick is a small power source consisting of three major components: a space qualified heat source (RHU), a thermopile (thermoelectric converter) and a set of rechargeable batteries. The Powerstick merges several devices developed earlier by space power programs. The RHU was developed by DOE for the Galileo and Ulysses missions, the thermopile is a combination of the early RTG technology and pace maker technology with new packaging techniques, and a lithium-ion rechargeable battery is currently being developed for space applications. NASA has recently awarded a Small Business Technology Transfer (STTR) contract to Hi-Z Technology, Inc. of San Diego to manufacture a miniaturized thermopile and provide a preliminary design of the Powerstick. JPL's Solar System Exploration Program funded Powerstick prototype design and fabrication contract with Swales & Associates, Inc. The Swales unit and the Hi-Z thermopile will be integrated at JPL. This integrated prototype with the thermopile, rechargeable batteries and electrical RHU simulator will be tested at JPL. At the same time JPL is pursuing a "ruggedized" Powerstick development with the Russian company BIAPOS. BIAPOS is to independently design, build and deliver to JPL for testing their own version of the Powerstick. According to the technology development road map for small space sources the American and Russian efforts will lead to the development of an engineering and qualification Powerstick unit by the end of the century. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Borshchevsky, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 465 EP 468 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900088 ER PT B AU Underwood, ML Dobbs, M Giglio, J AF Underwood, ML Dobbs, M Giglio, J GP AMER INST CHEM ENGINEERS TI AMTEC flight experiment progress and plans SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB An experiment is being developed to validate the performance of AMTEC technology in the space microgravity environment. A group of AMTEC cells have been fabricated and assembled into an experiment module and instrumented for operation. The experiment is manifested as a Hitchhiker payload on STS-88 now planned for flight in July 1998. The AMTEC cells will be operated in space for up to ten days. The microgravity developed distribution of the sodium working fluid will be frozen in place before the cells are returned to Earth. Upon return the cells will be destructively evaluated to determine the location of the sodium and to assure that the sodium has been properly controlled by the sodium control elements. This paper describes the experiment purpose, status, and plans for the flight operations and data analysis. An overview of how this experiment fits into the overall AMTEC development is also provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Underwood, ML (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 484 EP 488 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900092 ER PT B AU Kimnach, GL Lebron, RC Fox, DA AF Kimnach, GL Lebron, RC Fox, DA GP AMER INST CHEM ENGINEERS TI Design and testing of a breadboard electrical power control unit for the fluid combustion facility experiment SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Fluid Combustion Facility (FCF) Project at the NASA Lewis Research Center in Cleveland, OH and the Sundstrand Corporation in Rockford, IL are jointly developing an Electrical Power Converter Unit (EPCU) for the Fluid Combustion Facility to be flown on the International Space Station (ISS). The FCF facility experiment contains three racks: A core rack, a combustion rack, and a fluids rack. The EPCU will be used as the power interface to the ISS 120V(dc) power distribution system by each FCF experiment rack which requires 28V(dc). The EPCU is a modular design which contains three 120V(dc)-to-28V(dc) full-bridge, power converters rated at 1 kW(e) each; bus transferring input relays and solid-state, current-limiting input switches; 48 current-limiting, solid-state, output switches; and control and telemetry hardware. The EPCU has all controls required to autonomously share power among the power converters and-if absolutely necessary-shed loads. The EPCU, which maximizes the usage of allocated ISS power and minimizes loss of power to loads, can be paralleled with other EPCUs. This paper overviews the electrical design and operating characteristics of the EPCU and provides test data for a breadboard design. C1 NASA, Lewis Res Ctr, Power Technol Div, Cleveland, OH 44135 USA. RP Kimnach, GL (reprint author), NASA, Lewis Res Ctr, Power Technol Div, 21000 Brookpark Rd,MS 301-5, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 532 EP 537 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900099 ER PT B AU Hoffman, DJ Scheiman, DA AF Hoffman, DJ Scheiman, DA GP AMER INST CHEM ENGINEERS TI Thermal cycling of Mir cooperative solar array (MCSA) test panels SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Mir Cooperative Solar Array (MCSA) project was a joint US/Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA is currently being used to increase the electrical power on Mir and provide PV array performance data in support of Phase I of the International Space Station (ISS), which will use arrays based on the same solar cells used in the MCSA. The US supplied the photovoltaic power modules (PPMs) and provided technical and programmatic oversight while Russia provided the array support structures and deployment mechanism and built and tested the array. In order to ensure that there would be no problems with the interface between US and Russian hardware, an accelerated thermal life cycle test was performed at NASA Lewis Research Center on two representative samples of the MCSA. Over an eight-month period (August 1994 - March 1995), two 15-cell MCSA solar array "mini" panel test articles were simultaneously put through 24000 thermal cycles (+80 degrees C to 100 degrees C), equivalent to four years on-orbit. The test objectives, facility, procedure and results are described in this paper. Post-test inspection and evaluation revealed no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early as an artifact of the test and removed from consideration. The interesting nature of the performance degradation caused by this one cell, which only occurred at elevated temperatures, is discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the US solar cell modules with the Russian support structure would be able to withstand at least 24000 thermal cycles (4 years on-orbit). C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hoffman, DJ (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 597 EP 602 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900110 ER PT B AU Kerslake, TW Hoffman, DJ AF Kerslake, TW Hoffman, DJ GP AMER INST CHEM ENGINEERS TI Mir Cooperative Solar Array flight performance data and computational analysis SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States (US) and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir, The MCSA was launched to Mir in November 1995 and installed on the Kvant-1 module in May 1996. Since the MCSA photovoltaic panel modules (PPMs) are nearly identical to those of the International Space Station (ISS) photovoltaic arrays, MCSA operation offered an opportunity to gather multi-year performance data on this technology prior to its implementation on ISS. Two specially designed test sequences were executed in June and December 1996 to measure MCSA performance. Each test period encompassed 3 orbital revolutions whereby the current produced by the MCSA channels was measured. The temperature of MCSA PPMs was also measured. To better interpret the MCSA flight data, a dedicated FORTRAN computer code was developed to predict the detailed thermal-electrical performance of the MCSA. Flight data compared very favorably with computational performance predictions. This indicated that the MCSA electrical performance was fully meeting pre-flight expectations. There were no measurable indications of unexpected or precipitous MCSA performance degradation due to contamination or other causes after 7 months of operation on orbit. Power delivered to the Mir bus was lower than desired as a consequence of the retrofitted power distribution cabling. The strong correlation of experimental and computational results further bolsters the confidence level of performance codes used in critical ISS electric power forecasting. In this paper, MCSA flight performance tests are described as well as the computational modeling behind the performance predictions. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Kerslake, TW (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 603 EP 608 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900111 ER PT B AU Kerslake, TW Scheiman, DA Hoffman, DJ AF Kerslake, TW Scheiman, DA Hoffman, DJ GP AMER INST CHEM ENGINEERS TI Pre-flight dark forward electrical testing of the Mir Cooperative Solar Array SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States (US) and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir. After final assembly in Russia, the MCSA was shipped to the NASA Kennedy Space Center (KSC) in the summer of 1995 and launched to Mir in November 1995. Program managers were concerned of the potential for MCSA damage during the transatlantic shipment and the associated handling operations. To address this concern, NASA Lewis Research Center (LeRC) developed an innovative dark-forward electrical test program to assess the gross electrical condition of each generator following shipment from Russia The use of dark test techniques, which allow the array to remain in the stowed configuration, greatly simplifies the checkout of large area solar arrays. MCSA dark electrical testing was successfully performed at KSC in July 1995 following transatlantic shipment. Data from this testing enabled engineers to quantify the effects of potential MCSA physical damage that would degrade on-orbit electrical performance. In this paper, an overview of the principles and heritage of photovoltaic array dark testing is given. The specific MCSA dark test program is also described including the hardware, software, testing procedures and test results. The current-voltage (IV) response of both solar cell circuitry and bypass diode circuitry was obtained. To guide the development of dark test hardware, software and procedures, a dedicated FORTRAN computer code was developed to predict the dark IV responses of generators with a variety of feasible damage modes. By comparing the actual test data with the predictions, the physical condition of the generator could be inferred. Based on this data analysis, no electrical short-circuits or open-circuits were detected. This suggested the MCSA did not sustain physical damage that affected electrical performance during handling and shipment from Russia to the US. Good agreement between the test data and computational predictions indicated MCSA electrical performance was amenable to accurate analysis and was well understood. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Kerslake, TW (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 619 EP 624 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900114 ER PT B AU Stevenson, SM AF Stevenson, SM GP AMER INST CHEM ENGINEERS TI Mars Pathfinder Rover-Lewis Research Center technology experiments program SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB An overview of NASA's Mars Pathfinder Program is given and the development and role of three technology experiments from NASA's Lewis Research Center and carried on the Mars Pathfinder rover is described. Two recent missions to Mars were developed and managed by the Jet Propulsion Laboratory, and launched late last year: Mars Global Surveyor in November 1996 and Mars Pathfinder in December 1996. Mars Global Surveyor is an orbiter which will survey the planet with a number of different instruments, and will arrive in September 1997, and Mars Pathfinder which consists of a lander and a small rover, landing on Mars July 4, 1997. These are the first two missions of the Mars Exploration Program consisting of a ten year series of small robotic martian probes to be launched every 26 months. The Pathfinder rover will perform a number of technology and operational experiments which will provide the engineering information necessary to design and operate more complex, scientifically oriented surface missions involving roving vehicles and other machinery operating in the martian environment. Because of its expertise in space power systems and technologies, space mechanisms and tribology, Lewis Research Center was asked by the Jet Propulsion Laboratory, which is heading the Mars Pathfinder Program, to contribute three experiments concerning the effects of the martian environment on surface solar power systems and the abrasive qualities of the Mars surface material. In addition, rover static charging was investigated and a static discharge system of several fine Tungsten points was developed and fixed to the rover. These experiments and current findings are described herein. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Stevenson, SM (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 722 EP 727 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900132 ER PT B AU Landis, GA Jenkins, PP Hunter, G AF Landis, GA Jenkins, PP Hunter, G GP AMER INST CHEM ENGINEERS TI Materials adherence experiment on Mars Pathfinder: Early results SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Materials Adherence Experiment ("MAE") on the Pathfinder "Sojourner" rover will measure the dust deposition rate. By August, the Sojourner Rover on Mars Pathfinder will have completed its primary mission, and the experiment will have data on dust deposition during the first three weeks of operation on Mars. This paper will present the initial data from the experiment. This will be the first presentation of the results from the Pathfinder MAE experiment. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 732 EP 733 PG 2 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900134 ER PT B AU Ferguson, DC AF Ferguson, DC GP AMER INST CHEM ENGINEERS TI The Wheel Abrasion Experiment - How abrasive is the Martian dust? SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Wheel Abrasion Experiment (WAE) is one of the technology experiments on the Mars Pathfinder Rover (Sojoumer) which will land and begin operations on the planet Mars in July, 1997. By abrading thin film metallic surfaces on one of Sojourner's wheels, and detecting the resulting changes of reflectivity with a special photovoltaic sensor, WAE will measure the abrasive characteristics of the Martian sand or dust In this paper, we review the purpose of the experiment, its general design and functionality, specifics about the wheel design and construction, the ground tests necessary for it to yield meaningful answers, and what it might tell us about the surface of Mars for use on future robotic revers and possible future manned exploration. Ground tests have already revealed the possibility of significant charging on wheeled vehicles in the Martian atmosphere. Further tests may enable us to better design future vehicles for use on Mars. C1 NASA, Space Environm Effects Branch, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ferguson, DC (reprint author), NASA, Space Environm Effects Branch, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 734 EP 737 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900135 ER PT B AU Wilt, DM Jenkins, PP Scheiman, DA AF Wilt, DM Jenkins, PP Scheiman, DA GP AMER INST CHEM ENGINEERS TI Photodetector development for the wheel abrasion experiment on the Sojourner microrover of the Mars Pathfinder mission SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB On-board the Mars Pathfinder spacecraft, launched in December of 1996, is a small roving vehicle named Sojourner. On Sojourner is an experiment to determine the abrasive characteristics of the Martian surface, called the Wheel Abrasion Experiment (WAE). The experiment works as follows: one of the wheels of the rover has a strip of black anodized aluminum bonded to the tread. The aluminum strip has thin coatings of aluminum, nickel and platinum deposited in patches. There are five (5) patches or samples of each metal, and the patches range in thickness from 200 Angstrom to 1000 Angstrom. The different metals were chosen for their differing hardness and their environmental stability. As the wheel is spun in the Martian soil, the thin patches of metal are abraded away, exposing the black anodization. The abrasion is monitored by measuring the amount of light reflected off of the samples. A photodetector was developed for this purpose, and that is the subject of this paper. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Wilt, DM (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 302-1, Cleveland, OH 44135 USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 738 EP 742 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900136 ER PT B AU Kolecki, JC AF Kolecki, JC GP AMER INST CHEM ENGINEERS TI Electrostatic charging of the Mars Pathfinder rover and charging phenomena on the planet Mars SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB While the Mars Pathfinder rover was being developed, laboratory tests and calculations predicted that it would accumulate a sizable electrostatic charge as it moved over the Martian surface. The result could be a sustained Paschen discharge through the Martian atmosphere. Consequently, a recommendation was implemented to add discharge points as a precaution against charging, and, subsequently, to modify rover on-board electronics. This paper contains a summary of the Pathfinder charging work, then goes on to advance preliminary arguments supporting the general occurrence of electric charging and discharge phenomena on Mars, and to recommend instruments that might be sent to Mars to observe and measure these phenomena. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Kolecki, JC (reprint author), NASA, Lewis Res Ctr, Mail Stop 302-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 749 EP 752 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900138 ER PT B AU Chock, R Ferguson, DC AF Chock, R Ferguson, DC GP AMER INST CHEM ENGINEERS TI Environments workbench - An official NASA space environments tool SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Environments WorkBench (EWB) is an integrated software tool for evaluation and prediction of space environments in low Earth Orbit (LEG). EWB v5.0 was unveiled earlier this year. It is the official International Space Station (ISS) plasma prediction and verifications tool, and has been adopted as the official integrated tool of the national Space Environments and Effects Program. In this paper, we describe the history of the tool and the motivation behind an integrated software tool for LEO space environments and effects, the software architecture, the capabilities and features of the code, the environments and effects it enables one to evaluate, the code verification and validation, and the method by which it can be used to make initial LEO hardware design easier and faster. Sample analyses of LEO spacecraft will be given, and we conclude by describing how the code may be obtained, and on what platforms it will operate. C1 NASA, Space Environm Effects Branch, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chock, R (reprint author), NASA, Space Environm Effects Branch, Lewis Res Ctr, 2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 753 EP 757 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900139 ER PT B AU Landis, GA AF Landis, GA GP AMER INST CHEM ENGINEERS TI Mars dust removal technology SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Mars atmosphere contains a significant load of suspended dust. Settling of atmospheric dust onto the surface of the solar array is potentially a lifetime limiting factor for a power system on any Mars mission. For long-term operation of arrays on Mars, it may be necessary to develop techniques to remove deposited dust. Dust is expected to adhere to the array by Van der Waals adhesive forces. These forces are quite strong at the dust particle sizes expected. If the array surface is insulating, it is possible that they may also be subject to electrostatic adhesion, which may be extremely strong. Dust removal methods must overcome this force. Dust removal methods can be categorized briefly into four categories: natural, mechanical, electromechanical, and electrostatic. The environment of Mars is expected to be an ideal one for use of electrostatic dust removal techniques. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 764 EP 767 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900141 ER PT B AU Halpert, G Narayanan, SR Valdez, T Chun, W Frank, H Kindler, A Surampudi, S Kosek, J Cropley, C LaConti, A AF Halpert, G Narayanan, SR Valdez, T Chun, W Frank, H Kindler, A Surampudi, S Kosek, J Cropley, C LaConti, A GP AMER INST CHEM ENGINEERS TI Progress with the direct methanol liquid-feed fuel cell system SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Direct Methanol, Liquid-Feed Fuel Cell with Proton Exchange Membrane (DMLFFC/PEM) technology offers a number of system advantages which on the whole compare favorably with the direct hydrogen PEM fuel cell system or the indirect fuel cell system. This paper summarizes progress in cell, stack, and system development based on the Direct Methanol, Liquid-Feed Fuel Cell concept. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Halpert, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 774 EP 778 DI 10.1109/IECEC.1997.660237 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900143 ER PT B AU Fleurial, JP Borshchevsky, A Caillat, T Ewell, R AF Fleurial, JP Borshchevsky, A Caillat, T Ewell, R GP AMER INST CHEM ENGINEERS TI New materials and devices for thermoelectric applications SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The development of new, more efficient materials and devices is the key to expanding the range of application of thermoelectric generators and coolers. In the last couple of years, efforts to discover "breakthrough" thermoelectric materials have intensified, in particular in the U.S. Recent results on novel materials have already demonstrated that dimensionless figure of merit ZT values 40 to 50% larger than 1.0, the current limit, could be obtained in the 475 to 950K temperature range. New terrestrial power generation applications have been recently described in the literature. There exists a wide range of heat source temperatures for these applications, from low grade waste heat, at 325-350K, up to 850 to 1100K, such as in the heat recovery from a processing plant of combustible solid waste. The automobile industry has also recently developed a strong interest in a waste exhaust heat recovery power source operating in the 375-750K temperature range to supplement or replace the alternator and thus decrease fuel consumption. Based on results achieved to date at the Jet Propulsion Laboratory (JPL) on novel materials, the performance of an advanced segmented generator design operating in a large 300-945K temperature gradient is predicted to achieve about 15% conversion efficiency. This would be a very substantial improvement over state-of-the-art (SOA) thermoelectric power converters. Such a terrestrial power generator could be using waste heat or liquid fuels as a heat source. High performance radioisotope generators (RTG) are still of interest for deep space missions but the shift towards small, light spacecrafts has developed a need for advanced power sources in the watt to milliwatt range. The "powerstick" concept would provide a sturdy, compact, lightweight and low cost answer to this need. The development of thin film thermoelectric devices also offer attractive possibilities. The combination of semiconductor technology, thermoelectric films and high thermal conductivity materials could lead to the fabrication of light weight, high voltage devices with high cooling or high electrical power density characteristics. The use of microcoolers for the thermal management of power electronics is of particular interest. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fleurial, JP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 4 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1080 EP 1085 DI 10.1109/IECEC.1997.661920 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900198 ER PT B AU Good, BS Chubb, DL AF Good, BS Chubb, DL GP AMER INST CHEM ENGINEERS TI A comparison of planar and cylindrical thermophotovoltiac energy conversion systems SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB We have previously reported results [1] of computer modeling of planar thermophotovoltaic (TPV) systems. it is well known, however, that the geometry of such systems is one of the primary determinants of system performance. At the NASA Lewis Research Center, we have produced a new computer modeling code that permits the investigation of a wide variety of system configurations. We have used this code to perform an analysis of the effects of system geometry on performance. The general system under consideration consists of an emitter, a protective window, a filter, a PV cell, and lateral reflectors. The computer code solves a set of nine algebraic equations for the radiation fluxes on both sides of the emitter and filter, and the inward-facing surfaces of the emitter, cell, and three distinct regions of the lateral reflectors. The model code requires at initialization the optical properties of the components, along with the emitter and cell temperatures. It is known that the optical properties of the various system components are functions of wavelength. However, for large regions of the spectrum, these properties may be essentially constant, or slowly varying functions of wavelength. In order to make the best use of experimentally-available data while keeping the input as simple as possible, we divide the spectrum into a number of "constant" bands, over which the optical properties are assumed not to vary, and "variable" bands, over which the properties are assumed to be strong functions of wavelength. The equations described above are solved for wavelengths that range from 1 to 10,000 nm, for a combination of constant and variable bands. Because the emitted powers of the hot components are strongly temperature-dependent, the above computation must be performed iteratively, adjusting the component temperatures until energy balance at each component surface is achieved. In this paper we present results of an analysis of the effects of the geometry of planar and cylindrical TPV systems on the efficiency of the thermal cavity. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Good, BS (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,302-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1113 EP 1118 DI 10.1109/IECEC.1997.661926 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900204 ER PT B AU Wilt, DM Fatemi, NS Jenkins, PP Weizer, VG Hoffman, RW Murray, CS Riley, DR AF Wilt, DM Fatemi, NS Jenkins, PP Weizer, VG Hoffman, RW Murray, CS Riley, DR GP AMER INST CHEM ENGINEERS TI Electrical and optical performance characteristics of p/n InGaAs monolithic interconnected modules SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) devices series-connected on a single semiinsulating indium phosphide (InP) substrate. The MIMs are exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 cm(2) device consisting of eight (8) series interconnected cells. MIM devices, produced from 0.74eV InGaAs, have demonstrated V-oc = 3.2 volts, J(sc) = 70 mA/cm(2) and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurements ( > 2 mu M) of these devices indicate a reflectivity of > 82%. MIM devices produced from 0.55eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AMO) have been demonstrated. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Wilt, DM (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,MS 302-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1119 EP 1124 DI 10.1109/IECEC.1997.661927 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900205 ER PT B AU Williams, RM Ryan, MA Phillips, WM AF Williams, RM Ryan, MA Phillips, WM GP AMER INST CHEM ENGINEERS TI Loss of alkali oxide from beta '' alumina and its importance to AMTEC life issues SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Loss of sodium oxide into a gas phase comprised of low to high pressure sodium at typical AMTEC operating conditions does not seem indicated as a life limiting step under projected conditions. Sodium oxide loss is strongly thermally activated and strongly suppressed by external sodium gas pressure. However, loss of sodium oxide into liquid sodium may be, but is not clearly known to be, much more rapid than loss into the gas phase and could result both BASE degradation and enhanced corrosion of other AMTEC components. This favors conservative selection of vapor-fed cell designs and may significantly influence materials selection and use of getters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1220 EP 1223 DI 10.1109/IECEC.1997.661942 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900220 ER PT B AU Lin, EI AF Lin, EI GP AMER INST CHEM ENGINEERS TI Analytical thermal model validation for Cassini radioisotope thermolelectric generator SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Saturn-bound Cassini spacecraft is designed to rely, without precedent, on the waste heat from its three radioisotope thermoelectric generators (RTGs) to warm the propulsion module subsystem, and the RTG end dome temperature is a key determining factor of the amount of waste heat delivered. A previously validated SINDA thermal model of the RTG was the sole guide to understanding its complex thermal behavior, but displayed large discrepancies against some initial thermal development test data A careful revalidation effort led to significant modifications and adjustments of the model, which result in a doubling of the radiative heat transfer from the heat source support assemblies to the end domes and bring up the end dome and flange temperature predictions to within 2 degrees C of the pertinent test data The increased inboard end dome temperature has a considerable impact on thermal control of the spacecraft central body. The validation process offers an example of physically-driven analytical model calibration with test data from not only an electrical simulator but also a nuclear-fueled flight unit, and has established the end dome temperatures of a flight RTG where no in-flight or ground-test data existed before. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lin, EI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1445 EP 1450 DI 10.1109/IECEC.1997.661982 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900260 ER PT B AU Choi, MK AF Choi, MK GP AMER INST CHEM ENGINEERS TI An experimental technique to resolve the Landsat-7 spacecraft heater debond issue SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Results of thermal vacuum testing of simulated 100% debonded equipment panel heaters revealed that with the primary heater on all the time and an 80 degrees C heat sink, the worst case maximum heater temperature is 166 degrees C for a .448 W/cm(2) heater power density, and 223 degrees C for a .673 W/cm(2) heater power density. All the heaters on the equipment panels of the Landsat-7 spacecraft have a maximum heater power density of .460 W/cm(2) or less, with only either the primary or redundant heater turned on. The equipment panel heaters have a 200 degrees C maximum allowable temperature in the manufacturer's specifications. The maximum heater temperature for a 100% debonded heater in the worst case is 170 degrees C, which has a 30 degrees C margin. In order to exceed the 200 degrees C maximum allowable temperature, the maximum heater power density needs to be higher than .589 W/cm(2). Data from the tests to induce heater failure showed that the heater failed after it had reached 250 degrees C to 253 degrees C for 25 minutes. In order to exceed 250 degrees C, the maximum heater power density needs to be higher than .9 W/cm(2). For these reasons, there was no need to replace the equipment panel heaters which were suspected to have debonded. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Choi, MK (reprint author), NASA, Goddard Space Flight Ctr, Code 724, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1451 EP 1456 DI 10.1109/IECEC.1997.661983 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900261 ER PT B AU Choi, MK AF Choi, MK GP AMER INST CHEM ENGINEERS TI An innovative thermal balance test for Landsat-7 ETM+ instrument: Cheaper, faster, unusual, successful SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB A thermal balance test with cold vacuum chamber walls is needed at the instrument level for the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) instrument. The initial approaches for the thermal balance test had significant impacts on the cost and schedule. This paper presents an innovative approach, which is cheaper, faster and better. It consists of two modifications to the baseline thermal vacuum (TN) test profile, and win maintain the total test time in the vacuum chamber the same as the baseline. The first modification is to change the chamber wall temperature from 0 degrees C to -90 degrees C and enable the standby and safehold flight heaters during the 2.6-day radiative cooler cooldown to perform a cold thermal balance. The second modification is to reverse the order of 20% and 30% ETM+ duty cycles during orbital simulations in orbits #36 through #44, and change the chamber wall temperature from 0 degrees C to -90 degrees C and increase the duty cycle from 30% to 36% during orbital simulations in orbits #25 through #40 to perform a hot thermal balance. Reversing the order of 20% and 30% duty cycles in orbits #36 through #44 increases the time for 30% duty cycle continuous simulation by .3 day, and has-a better chance of reaching a dynamic equilibrium. The innovative thermal balance test requires some extra test preparation time for adding kapton film heaters, kapton tape and a .0508 mm thick aluminized kapton cover to the Thematic Mapper Calibrator (TMC) test fixture. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Choi, MK (reprint author), NASA, Goddard Space Flight Ctr, Code 724, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1457 EP 1462 DI 10.1109/IECEC.1997.661984 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900262 ER PT B AU Choi, MK AF Choi, MK GP AMER INST CHEM ENGINEERS TI Thermal design of Landsat-7 ETM+ Earth space background simulators SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB In the Landsat-7 observatory thermal balance/thermal vacuum (TB/TV) test, deployments of the radiative cooler door and full aperture calibrator (FAC) of the Enhanced Thematic Mapper Plus (ETM+) scanner will be tested. A space background simulator (SBS) to simulate the space radiative heat sink for the cooler aperture and the interior of the cooler door has been designed, built and tested in a vacuum chamber. The SBS is an open loop cryogenics system using a liquid helium dewar. Results of the SBS thermal vacuum test showed that it satisfactorily operated and simulated the space radiative heat sink. An earth background simulator (EBS) to simulate the equivalent heat sink temperature for the mapper aperture of the scanner has also been designed and built. It also protects the FAC and FAC actuator from being exposed to the liquid nitrogen cooled chamber walls. This paper presents the thermal design of the SBS and EBS, and the SBS thermal vacuum test and its results. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Choi, MK (reprint author), NASA, Goddard Space Flight Ctr, Code 724, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1470 EP 1475 DI 10.1109/IECEC.1997.661986 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900264 ER PT B AU Choi, MK AF Choi, MK GP AMER INST CHEM ENGINEERS TI Thermal success of GGS SWE and HYDRA instruments: Design, analysis, verification, flight performance SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Solar Wind Experiment (SWE) is an essential instrument on the National Aeronautics and Space Administration (MASA) Global Geospace Science (GGS) Interplanetary Physics Laboratory (WIND) spacecraft. Fast Plasma Analyzer (HYDRA) is an essential instrument on the GGS Polar Plasma Laboratory (POLAR) spacecraft. WIND was successfully launched into orbit on November 1, 1994, and POLAR was successfully launched on February 24, 1996. The channeltrons of both the Vector Electron and Ion Spectrometers (VEIS) of SWE and Douo Deka Electron and Ion Spectrometers (DDEIS) of HYDRA, and the Faraday Cup (FC) detectors of SWE are critical components, which require an optimum operating temperature range of 0 degrees C to 20 degrees C. The thermal performance data in flight for the first two years for SWE and the first year for HYDRA showed that the operating temperatures of these components are within the optimum range. This paper presents the thermal design, thermal analysis, verification and flight thermal performance of SWE and HYDRA. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Choi, MK (reprint author), NASA, Goddard Space Flight Ctr, Code 724, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1476 EP 1481 DI 10.1109/IECEC.1997.661987 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900265 ER PT B AU Benner, SM Martins, MS AF Benner, SM Martins, MS GP AMER INST CHEM ENGINEERS TI Development of a neat-driven pulse pump for spacecraft applications - Part 2 SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB As mentioned in Reference 1, one serious deficiency when dealing with one or two-phase now spacecraft systems, such as thermal control systems, is the existence of a long-lived, high-reliability pump. The Heat Driven Pulse Pump (HDPP) consists of a grooved cylinder, two check valves, a wick, and two strip heaters. Three pumps are installed in parallel to provide a continuous flow rate. When heated, the working fluid, ammonia, vaporizes and produces the pumping pressure head. With only two simple moving parts, the HDPP should function over the long lifetimes required by current spacecraft without maintenance or replacement. This paper provides the results of a second series of tests that were performed after developing an automated control system. These included the effect of sink temperature, the maximum allowable power to the pumps, the influence of the reservoir on flow rate oscillations, and the effect of the timing sequence on now rate oscillations. For most of the tests, the sink and saturation temperatures were set to 15 degrees C and 28 degrees C, respectively. Applying 50 Watts alternatively to each pump generated an average flow rate of 28 g/min, which is capable of removing 600 W of heat from an instrument. The timing sequence was optimized by turning each pump heater on for 20 seconds at a time but then overlapping the operation of the heaters by 4 seconds. One disadvantage of this timing sequence is that it requires twice the power for 4 seconds. While the average now rate remained the same, compared to applying 50 watts sequentially to each pump, the magnitude of the oscillations were reduced by roughly one third. By using "off the shelf" 1/3 psi pressure drop check valves, the oscillations could not be eliminated. The best way to dampen the oscillations, short of designing a lower pressure drop check valve for space applications, is to adjust the timing sequence. Using a timing sequence also allowed the recovery time for the pumps to be optimized. The performance of the pumps was sensitive to the temperature of the sink that maintained the cold bias required by the pumps. As a result, the control system must take the sink temperature into consideration. For a required loop saturation temperature, a corresponding sink temperature needs to be maintained. The next step is to develop a flight experiment to test the operation of the HDPP in a micro-gravity environment. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Benner, SM (reprint author), NASA, Goddard Space Flight Ctr, Code 724, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1482 EP 1485 DI 10.1109/IECEC.1997.661988 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900266 ER PT B AU Voecks, GE Rohatgi, NK Jan, DL Ferraro, NW Moore, SH Warshay, M Prokopius, PR Edwards, HS Smith, GD AF Voecks, GE Rohatgi, NK Jan, DL Ferraro, NW Moore, SH Warshay, M Prokopius, PR Edwards, HS Smith, GD GP AMER INST CHEM ENGINEERS TI Operation of the 25 kW NASA Lewis Research Center Solar Regenerative Fuel Cell Testbed Facility SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB Assembly of the NASA Lewis Research Center (LeRC) Solar Regenerative Fuel Cell (RFC) Testbed Facility has been completed and system testing has proceeded. This facility includes the integration of two 25 kW photovoltaic solar cell arrays, a 25 kW proton exchange membrane (PEM) electrolysis unit, four 5 kW PEM fuel cells, high pressure hydrogen and oxygen storage vessels, high purity water storage containers, and computer monitoring, control and data acquisition. The fuel cell and electrolyzer subsystems' installation was carried out by the Jet Propulsion Laboratory (JPL). The photovoltaic arrays and electrical interconnect to the electrolyzer were provided by the U. S. Navy/China Lake Naval Air Warfare Center. JPL is responsible for conducting the testing and operations at the LeRC facility. There are multiple objectives for this program. The near term objectives are: (1) design, assemble, and test the solar RFC power plant system to serve as a pre-prototype operational testbed facility; (2) evaluate performance criteria of the total system, subsystems, and components against various operational duty cycles; and (3) develop automation and controls commensurate with advanced system operating requirements. The long term objectives are: (1) develop a highly reliable, long life, highly efficient solar RFC power system for future manned space missions; and 2) demonstrate the dual use aspects of RFCs applicable to commercial and military applications. The system description and initiation of system testing constitute Phase I of multiple activities planned to take place in the next few years. System modeling is being performed in parallel with the experimental testing and will be used to determine the most efficient system design, from the standpoint of weight, volume and cost of electrical power. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Voecks, GE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1543 EP 1549 PG 7 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900277 ER PT B AU Christopher, DA Beach, RF Barton, JR AF Christopher, DA Beach, RF Barton, JR GP AMER INST CHEM ENGINEERS TI A flywheel energy storage system test on the International Space Station SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Christopher, DA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 1762 EP 1766 PG 5 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900316 ER PT B AU Gluck, PR AF Gluck, PR GP AMER INST CHEM ENGINEERS TI Spacecraft power management software for the new millennium SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Jet Propulsion Laboratory's (JPL's) New Millennium Program (NMP) is a proving ground for 21st century spacecraft technologies. Chief among these technologies is the field of spacecraft automation. The NMP Deep Space One (DS1) mission will have the most sophisticated autonomous software ever flown an robotic spacecraft. An important element of this software is the Power Management System. Since power is a system resource, this software spans many mission and spacecraft systems. It must predict future: spacecraft power generation, plan activities within expected power resources, query on-board navigation and attitude control systems for position and attitude information (which impact solar power generation), monitor and analyze power system state and health, and diagnose and respond to power system failures and emergencies. This paper describes the DS1 Power Management System and its rare in the DS1 autonomy software. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gluck, PR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 2228 EP 2230 PG 3 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900400 ER PT B AU Shirbacheh, M AF Shirbacheh, M GP AMER INST CHEM ENGINEERS TI Power and pyro subsystems for Mars Pathfinder SO IECEC-97 - PROCEEDINGS OF THE THIRTY-SECOND INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE, VOLS 1-4: VOL.1: AEROSPACE POWER SYSTEMS AND TECHNOL; VOL 2: ELECTROCHEMICAL TECHNOL, CONVERSION TECHNOL, THERMAL MANAGEMENT; VOLS 3: ENERGY SYSTEMS, RENEWABLE ENERGY RESOURCES, ENVIRONMENTAL IMPACT, POLICY IMPACTS ON ENERGY; VOL 4: POST DEADLINE PAPERS, INDEX LA English DT Proceedings Paper CT 32nd Intersociety Energy Conversion Engineering Conference (IECEC-97) CY JUL 27-AUG 02, 1997 CL HONOLULU, HI SP Amer Inst Chem Engineers, Amer Nucl Soc, SAE Int, AIAA, ASME, IEEE AB The Power and Pyre Subsystem (PPS) for Mars Pathfinder was designed to support the spacecraft activities during Launch, Cruise, Entry and Landing and Mars operation phases of the mission. The key design constraints were cost, volume and mass. The PPS consists of solar arrays, batteries and power electronics. This paper describes the Mars pathfinder mission, key requirements on PPS, PPS system architecture and description of each element of the PPS system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shirbacheh, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4515-0 PY 1997 BP 2231 EP 2236 PG 6 WC Engineering, Aerospace; Electrochemistry; Engineering, Chemical; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK53Q UT WOS:000072467900401 ER PT B AU Hammoud, A Gerber, S Baumann, E Overton, E AF Hammoud, A Gerber, S Baumann, E Overton, E GP IEEE TI Development of a 1 kW, 200 degrees C Mapham inverter utilizing high temperature components SO IEEE 1997 ANNUAL REPORT - CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA, VOLS I AND II LA English DT Proceedings Paper CT 66th Annual Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) CY OCT 19-22, 1997 CL MINNEAPOLIS, MN SP IEEE Dielect & Elect Insulat Soc AB Electronic systems and components are often exposed to high temperature environment in space-based applications, nuclear power facilities, and geothermal energy extraction fields. A key requirement for these systems is, therefore, to withstand the high temperature exposure while maintaining efficient and reliable operation. Efforts were taken to design and develop a high temperature power inverter capable of 200 degrees C operation. In this work, a 1 kW, 20 kHz Mapham inverter was designed and built utilizing components developed for high temperature operation. These components, which included capacitors, inductors, transformers, were developed and demonstrated at 200 degrees C. The inverter system was evaluated as a function of temperature at different load levels. The inverter system, excluding its input, control and logic circuitries, was characterized at temperatures from ambient to 200 degrees C at 0%, 50%, and 100% resistive loading. With an applied input voltage of 75 VDC, the inverter produced an output of 250 VAC. The results obtained, which have indicated good operational characteristics of the inverter up to 200 degrees C, are presented and discussed. RP Hammoud, A (reprint author), NYMA INC,NASA,LEWIS RES GRP,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3852-9 PY 1997 BP 194 EP 200 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA BJ96D UT WOS:A1997BJ96D00046 ER PT B AU McCollum, MB Clark, TL AF McCollum, MB Clark, TL GP IEEE TI Control of unintentionally generated low frequency RF fields SO IEEE 1997 INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY - SYMPOSIUM RECORD LA English DT Proceedings Paper CT IEEE 1997 International Symposium on Electromagnetic Compatibility CY AUG 18-22, 1997 CL AUSTIN CONVENT CTR, AUSTIN, TX SP Amplifier Res, Compliance Engn, EMC Test Syst, ENR Newsletter, Schlegel Corp, Chomerics, Compliance Design, Fischer Custom Commun, Intertek Testing Serv, Omega Shielding Prod, Inc, Technit Shielding, TUV Prod Serv, Vanguard Prod HO AUSTIN CONVENT CTR AB Radiated emissions and susceptibility requirements imposed in bands where intentional RF reception or transmission does not occur is problematical. It is often desired to compare radiated emissions with radiated susceptibility performance to assess system level compatibility. For both theoretical and practical measurement limitations, this is not realistic. A limit and test method are proposed which work around the present limitations and provide direct comparison of radiated emissions and radiated susceptibility performance, in those cases where only unintentional emissions and reception are of interest (non-tunable electronics). C1 NASA, George C Marshall Space Flight Ctr, Electromagnet & Aerosp Environm Branch, MSFC, AL USA. RP McCollum, MB (reprint author), NASA, George C Marshall Space Flight Ctr, Electromagnet & Aerosp Environm Branch, MSFC, AL USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4140-6 PY 1997 BP 314 EP 319 DI 10.1109/ISEMC.1997.667695 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BK64P UT WOS:000072926700061 ER PT B AU Perez, R AF Perez, R GP IEEE TI Signal integrity issues in ASIC and FPGA design SO IEEE 1997 INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY - SYMPOSIUM RECORD LA English DT Proceedings Paper CT IEEE 1997 International Symposium on Electromagnetic Compatibility CY AUG 18-22, 1997 CL AUSTIN CONVENT CTR, AUSTIN, TX SP Amplifier Res, Compliance Engn, EMC Test Syst, ENR Newsletter, Schlegel Corp, Chomerics, Compliance Design, Fischer Custom Commun, Intertek Testing Serv, Omega Shielding Prod, Inc, Technit Shielding, TUV Prod Serv, Vanguard Prod HO AUSTIN CONVENT CTR AB Most often when addressing electromagnetic compatibility issues in electronic design of analog and digital circuits, EMC principles such as grounding, coupling, emissions, shielding, ..etc are commonly scrutinized. Studies and research within EMC normally extends to the more fundamental principles of interference and compatibility as developed from the basic framework of electromagnetic theory. This framework has lately been extended to include computational methods for the solution of interference problems that are otherwise difficult to address analytically. However, it is usually observed that newly design hardware first encounter electromagnetic interference in the area of signal integrity where the design must overcome the inherited electromagnetic constraints imposed by high speed logic and the very low noise threshold levels of analog components. Addressing the most important signal integrity issues in digital electronic design, and which are common to most present design, are briefly covered in this paper, as well as the relevance of such issues to the electromagnetic compatibility principles previously mentioned. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Perez, R (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 IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4140-6 PY 1997 BP 334 EP 339 DI 10.1109/ISEMC.1997.667699 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BK64P UT WOS:000072926700065 ER PT B AU Perez, R AF Perez, R GP IEEE TI A simple computational electromagnetic analysis example of electromagnetic coupling to pyrocircuits SO IEEE 1997 INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY - SYMPOSIUM RECORD LA English DT Proceedings Paper CT IEEE 1997 International Symposium on Electromagnetic Compatibility CY AUG 18-22, 1997 CL AUSTIN CONVENT CTR, AUSTIN, TX SP Amplifier Res, Compliance Engn, EMC Test Syst, ENR Newsletter, Schlegel Corp, Chomerics, Compliance Design, Fischer Custom Commun, Intertek Testing Serv, Omega Shielding Prod, Inc, Technit Shielding, TUV Prod Serv, Vanguard Prod HO AUSTIN CONVENT CTR AB Analysis of electromagnetic coupling to pyre circuits with the objective of preventing adverse effects such as un-intentional firing, have been studied in the past using a variety of analytical approaches. It is proposed that a much simpler and faster approach, based on computational electromagnetic, can provide similar results. A portion of a pyro MOSFET circuit is first examined addressing failure modes within the design that can un-intentionally fire a pyre device if adverse electromagnetic fields of sufficient strength are present. The electrical conditions that will also contribute for the pyre circuits to fire un-intentionally are also discussed. Finally, the method of moments is used to address the field-to wire coupling scenario and to find if the necessary induced voltages within the pyre circuits are sufficient for a firing condition. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Perez, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4140-6 PY 1997 BP 573 EP 579 DI 10.1109/ISEMC.1997.667745 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BK64P UT WOS:000072926700111 ER PT S AU Bryson, S Johan, S Schlecht, L AF Bryson, S Johan, S Schlecht, L GP IEEE COMP SOC TI An extensible interactive visualization framework for the virtual windtunnel SO IEEE 1997 VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM, PROCEEDINGS SE PROCEEDINGS OF THE IEEE VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM LA English DT Proceedings Paper CT Virtual Reality Annual International Symposium CY MAR 01-05, 1997 CL ALBUQUERQUE, NM SP IEEE, Comp Soc, Tech Comm Comp Graph, IEEE, Neural Network Counc Virtual Real Techn Comm AB This paper describes a new software framework for the virtual windtunnel, a virtual reality-based, near-real-time interactive system for scientific visualization. This framework meets the requirements of extensibility, interactive performance, and interface independence. Creating a framework which meets ail of these requirements presented a major challenge We describe this framework's object-oriented structure and process architecture, including interprocess communications and control. Device independence of both the command and display structures are developed, providing the ability to use a wide variety of interface hardware options. The resulting framework supports a high-performance visualization environment which cart be easily extended to new capabilities as desired. RP Bryson, S (reprint author), NASA,AMES RES CTR,MRI INC,MOFFETT FIELD,CA 94035, USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1087-8270 BN 0-7803-3948-7 J9 P IEEE VIRT REAL ANN PY 1997 BP 106 EP 113 DI 10.1109/VRAIS.1997.583051 PG 8 WC Computer Science, Cybernetics; Computer Science, Software Engineering SC Computer Science GA BH39E UT WOS:A1997BH39E00015 ER PT S AU Ellis, SR Breant, F Menges, B Jacoby, R Adelstein, BD AF Ellis, SR Breant, F Menges, B Jacoby, R Adelstein, BD GP IEEE COMP SOC TI Factors influencing operator interaction with virtual objects viewed via head-mounted see-through displays: Viewing conditions and rendering latency SO IEEE 1997 VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM, PROCEEDINGS SE PROCEEDINGS OF THE IEEE VIRTUAL REALITY ANNUAL INTERNATIONAL SYMPOSIUM LA English DT Proceedings Paper CT Virtual Reality Annual International Symposium CY MAR 01-05, 1997 CL ALBUQUERQUE, NM SP IEEE, Comp Soc, Tech Comm Comp Graph, IEEE, Neural Network Counc Virtual Real Techn Comm AB A head-mounted visual display was used in a see-through format to present computer generated, space-stabilized, nearby wire-like virtual objects to 14 subjects. The visual requirements of their experimental tasks were similar to those needed for visually-guided manual assembly of aircraft wire harnesses. In the first experiment subjects visually traced wire paths with a head-referenced cursor, subjectively rated aspects of viewing, and had their vision tested before and after monocular, biocular, or stereo viewing. Only the viewing difficulty with the biocular display was adversely effected by the visual task. This viewing difficulty is likely due to conflict between looming and stereo disparity cues. A second experiment examined the precision with which operators could manually move ring-shaped virtual objects over virtual paths without collision. Accuracy of performance was studied as a function of required precision, path complexity, and system response latency. Results show that high precision tracing is most sensitive to increasing latency. Ring placement with less than 1.8 cm precision will require system latency less than 50 msec before asymptotic performance is found. RP Ellis, SR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 9 Z9 9 U1 0 U2 2 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1087-8270 BN 0-7803-3948-7 J9 P IEEE VIRT REAL ANN PY 1997 BP 138 EP 145 DI 10.1109/VRAIS.1997.583063 PG 8 WC Computer Science, Cybernetics; Computer Science, Software Engineering SC Computer Science GA BH39E UT WOS:A1997BH39E00019 ER PT B AU Pogorzelski, RJ York, RA AF Pogorzelski, RJ York, RA GP IEEE TI A simplified theory of coupled oscillator array phase control SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Pogorzelski, RJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 324 EP 327 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00078 ER PT B AU Pogorzelski, RJ Beckon, RJ AF Pogorzelski, RJ Beckon, RJ GP IEEE TI An application of the ''virtual spacecraft'' concept in evaluation of the Mars Pathfinder Lander low gain antenna SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Pogorzelski, RJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 558 EP 561 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00134 ER PT B AU Cwik, T Lou, J AF Cwik, T Lou, J GP IEEE TI Error estimation and h-adaptivity for optimal finite element analysis SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Cwik, T (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 664 EP 667 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00159 ER PT B AU Hussein, Z RahmatSamii, Y Kellogg, K AF Hussein, Z RahmatSamii, Y Kellogg, K GP IEEE TI Design and near-field measurement performance evaluation of the SeaWinds dual-beam reflector antenna SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Hussein, Z (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 852 EP 855 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00204 ER PT B AU Lee, RQ Simons, RN AF Lee, RQ Simons, RN GP IEEE TI Magnetic field distributions at close proximity of a tapered slot antenna SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI AB The magnetic field distribution at close proximity of a linearly tapered slot antenna was measured for several frequencies ranging from 2.3 to 10.8 GHz. These results provide some insight into the radiation mechanism of this type of antenna. RP Lee, RQ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1114 EP 1117 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00265 ER PT B AU Huang, J Pogorzelski, RJ AF Huang, J Pogorzelski, RJ GP IEEE TI Microstrip reflectarray with elements having variable rotation angles SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Huang, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 14 Z9 14 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1280 EP 1283 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00305 ER PT B AU Zaman, AJ Lee, RQ AF Zaman, AJ Lee, RQ GP IEEE TI A spherical to plane wave transformation using a reflectarray SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Zaman, AJ (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1284 EP 1287 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00306 ER PT B AU Huang, J Lou, M Caro, E AF Huang, J Lou, M Caro, E GP IEEE TI Super-low-mass spaceborne SAR array concepts SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Huang, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91009, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1288 EP 1291 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00307 ER PT B AU Bondyopadhyay, PK AF Bondyopadhyay, PK GP IEEE TI Omni-directional microstrip antenna on a near spherical surface. SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Meeting Abstract CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI C1 NASA,LYNDON B JOHNSON SPACE CTR,AV SYST BRANCH,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1520 EP 1520 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00361 ER PT B AU Zuffada, C Cwik, T Ditchman, C AF Zuffada, C Cwik, T Ditchman, C GP IEEE TI Synthesis of novel all-dielectric grating filters using genetic algorithms SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI RP Zuffada, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 1676 EP 1679 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00400 ER PT B AU Simons, RN Lee, RQ AF Simons, RN Lee, RQ GP IEEE TI Feasibility study of optically transparent microstrip patch antenna SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM 1997, VOLS 1-4 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium / North American Radio Science Meeting CY JUL 13-18, 1997 CL MONTREAL, CANADA SP IEEE Antennas & Propagat Soc, Natl Res Council Canada, Canadian Natl Comm URSI, US Natl Comm URSI AB The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively, They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications. RP Simons, RN (reprint author), NASA,LEWIS RES CTR,NYMA GRP,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 0 TC 11 Z9 11 U1 0 U2 3 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4178-3 PY 1997 BP 2100 EP 2103 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BJ61W UT WOS:A1997BJ61W00500 ER PT J AU Benedetto, S Divsalar, D Montorsi, G Pollara, F AF Benedetto, S. Divsalar, D. Montorsi, G. Pollara, F. TI A Soft-Input Soft-Output APP Module for Iterative Decoding of Concatenated Codes SO IEEE COMMUNICATIONS LETTERS LA English DT Article AB Concatenated coding schemes consist of the combination of two or more simple constituent encoders and interleavers. The parallel concatenation known as "turbo code" has been shown to yield remarkable coding gains close to theoretical limits, yet admitting a relatively simple iterative decoding technique. The recently proposed serial concatenation of interleaved codes may offer superior performance to that of turbo codes. In both coding schemes, the core of the iterative decoding structure is a soft-input soft-output (SISO) a posteriori probability (APP) module. In this letter, we describe the SISO APP module that updates the APP's corresponding to the input and the output bits, of a code, and show how to embed it into an iterative decoder for a new hybrid concatenation of three codes, to fully exploit the benefits of the proposed SISO APP module. C1 [Benedetto, S.; Montorsi, G.] Politecn Torino, I-10122 Turin, Italy. [Divsalar, D.; Pollara, F.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Benedetto, S (reprint author), Politecn Torino, I-10122 Turin, Italy. EM dariush@shannon.jpl.nasa.gov RI Montorsi, Guido/D-4867-2012; OI benedetto, sergio/0000-0002-7648-5396 NR 4 TC 342 Z9 357 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1089-7798 J9 IEEE COMMUN LETT JI IEEE Commun. Lett. PD JAN PY 1997 VL 1 IS 1 BP 22 EP 24 AR PII S 1089-7798(97)01348-3 DI 10.1109/4234.552145 PG 3 WC Telecommunications SC Telecommunications GA V04VS UT WOS:000207086500007 ER PT J AU Liu, AK Peng, CY Chang, SYS AF Liu, AK Peng, CY Chang, SYS TI Wavelet analysis of satellite images for coastal watch SO IEEE JOURNAL OF OCEANIC ENGINEERING LA English DT Article DE marine technology; marine vehicle detection and tracking; process monitoring; satellite applications; wavelet transforms ID SYNTHETIC-APERTURE RADAR AB The two-dimensional wavelet transform is a very efficient bandpass filter, which can be used to separate various scales of processes and show their relative phase/location. In this paper, algorithms and techniques for automated detection and tracking of mesoscale features from satellite imagery employing wavelet analysis are developed. The wavelet transform has been applied to satellite images, such as those from synthetic aperture radar (SAR), advanced very-high-resolution radiometer (AVHRR), and coastal zone color scanner (CZCS) for feature extraction. The evolution of mesoscale features such as oil slicks, fronts, eddies, and ship wakes can be tracked by the wavelet analysis using satellite data from repeating paths. Several examples of the wavelet analysis applied to various satellite images demonstrate the feasibility of this technique for coastal monitoring. RP Liu, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771, USA. NR 16 TC 46 Z9 50 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0364-9059 J9 IEEE J OCEANIC ENG JI IEEE J. Ocean. Eng. PD JAN PY 1997 VL 22 IS 1 BP 9 EP 17 DI 10.1109/48.557535 PG 9 WC Engineering, Civil; Engineering, Ocean; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA WL763 UT WOS:A1997WL76300002 ER PT J AU Jani, MG Barnes, NP Murray, KE Hart, DW Quarles, GJ Castillo, VK AF Jani, MG Barnes, NP Murray, KE Hart, DW Quarles, GJ Castillo, VK TI Diode-pumped Ho:Tm:LuLiF4 laser at room temperature SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE diode-pumped solid-state lasers; Ho:Tm: doped Scheelite materials; Ho:Tm:LuLiF4; Ho:Tm:YLiF4; Ho:Tm:YAG lasers at 2-mu m wavelength ID 2.1-MU-M AB diode-pumped room-temperature Ho:Tm:LuLiF4 laser achieved an optical efficiency of 9.4% under normal mode operation, Under similar experimental conditions, Ho:Tm:LuLiF4 yielded 1.5 times greater optical efficiency than Ho:Tm:YLiF4. Absorption spectra and lifetimes as a function of pump energy were measured for evaluation of this laser material. C1 SCI & TECHNOL CORP,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,NATL RES COUNCIL,HAMPTON,VA 23681. VLOC,TARPON SPRINGS,FL 34689. NR 21 TC 35 Z9 36 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JAN PY 1997 VL 33 IS 1 BP 112 EP 115 DI 10.1109/3.554905 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA WA194 UT WOS:A1997WA19400015 ER PT J AU Raybon, G Koren, U Miller, BI Chien, M Young, MG Capik, RJ Dreyer, K Derosier, RM AF Raybon, G Koren, U Miller, BI Chien, M Young, MG Capik, RJ Dreyer, K Derosier, RM TI A wavelength-tunable semiconductor amplifier/filter for add/drop multiplexing in WDM networks SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE adjunct multiplexing; WDM networks; semiconductor filter AB Reconfigurable channel drop in a wavelength-division multiplexed system is demonstrated using a packaged semiconductor amplifier/filter. The filter is electrically tunable over 9.0 nm with a 0.9-nm width and is used with an optical circulator to demultiplex three 5.0-Gb/s WDM channels spaced by 2.25 nm, A receiver sensitivity improvement and low optical crosstalk is observed over a dynamic range of nearly 10 dB. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. AT&T BELL LABS,RES,HOLMDEL,NJ 07733. RP Raybon, G (reprint author), AT&T BELL LABS,LUCENT TECHNOL,CRAWFORDS CORNER RD,HOLMDEL,NJ 07733, USA. NR 6 TC 19 Z9 19 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 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD JAN PY 1997 VL 9 IS 1 BP 40 EP 42 DI 10.1109/68.554475 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA VZ875 UT WOS:A1997VZ87500015 ER PT J AU Vorperian, V McLyman, WT AF Vorperian, V McLyman, WT TI Analysis of a PWM-resonant converter SO IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS LA English DT Article AB When a parallel resonant tank is excited by a bipolar current pulse train a sinusoidal voltage develops across the tank whose amplitude depends on the duty cycle of the pulse train An isolated secondary can be derived by applying the tank voltage to an isolation transformer whose magnetizing inductance acts as the resonant inductor of the tank circuit a de output voltage is obtained after rectification and filtering of the sinusoidal secondary voltage and regulation is achieved by controlling the duty cycle of the pulse train. The sinusoidal nature of the voltage across the isolation transformer alleviates some of the noise problems associated with parasitic capacitances of an isolation transformer when operated with square voltage waveforms. In this work the de and small-signal analysis of the converter is given and an equivalent small-signal circuit model is derived. Experimental results which confirm the validity of the model are presented. RP Vorperian, V (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 303-300,PASADENA,CA 91109, USA. NR 3 TC 1 Z9 1 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 0018-9251 J9 IEEE T AERO ELEC SYS JI IEEE Trans. Aerosp. Electron. Syst. PD JAN PY 1997 VL 33 IS 1 BP 163 EP 170 DI 10.1109/7.570734 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA WC812 UT WOS:A1997WC81200017 ER PT J AU Padgett, C KreutzDelgado, K AF Padgett, C KreutzDelgado, K TI A grid algorithm for autonomous star identification SO IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS LA English DT Article ID PATTERN AB An autonomous star identification algorithm is described that is simple and requires less computer resources than other such algorithm. In simulations using an 8 x 8 degree field of view (FOV), the algorithm identifies the correct section of sky on 99.7% of the sensor orientations where spatial accuracy of the imaged star is 1 pixel (56.25 are seconds) in standard deviation and the apparent brightness deviates by 0.4 units stellar magnitude. This compares very favorably with other algorithms in the literature. C1 SAN DIEGO STATE UNIV,SAN DIEGO,CA 92182. RP Padgett, C (reprint author), CALTECH,JET PROP LAB,AUTONOMOUS FEATURE & STAR TRACKING PROJECT,MS 198-235,PASADENA,CA 91109, USA. NR 13 TC 69 Z9 96 U1 3 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9251 J9 IEEE T AERO ELEC SYS JI IEEE Trans. Aerosp. Electron. Syst. PD JAN PY 1997 VL 33 IS 1 BP 202 EP 213 DI 10.1109/7.570743 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA WC812 UT WOS:A1997WC81200020 ER PT J AU Zuffada, C Cwik, T Jamnejad, V AF Zuffada, C Cwik, T Jamnejad, V TI Modeling radiation with an efficient hybrid finite-element integral-equation waveguide mode-matching technique SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE mode-matching methods; electromagnetic radiation ID CAVITY-BACKED ANTENNAS; SCATTERING; ARRAYS; EDGE AB A method is presented to model electromagnetic radiation, combining the finite-element technique in the penetrating portion of a three-dimensional (3-D) radiating structure with an integral equation on the outer surface of the computational domain, and with a waveguide mode-matching technique on a cross section of the feeding waveguide. The antenna can be of general shape, provided a portion of the surrounding medium up to a surface of revolution is chosen as part of the computational domain, This truncation scheme and the accurate source representation are more general than those existing in the literature for radiation modeling, An open-ended waveguide and a waveguide with a choke ring are analyzed and their radiation patterns are obtained and compared with available measurements. RP Zuffada, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 20 TC 11 Z9 11 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 JAN PY 1997 VL 45 IS 1 BP 34 EP 39 DI 10.1109/8.554238 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA WC125 UT WOS:A1997WC12500007 ER PT J AU Musgrave, JL Guo, TH Wong, EM Duyar, A AF Musgrave, JL Guo, TH Wong, EM Duyar, A TI Real-time accommodation of actuator faults on a reusable rocket engine SO IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY LA English DT Article DE fault diagnosis; rockets; model-based fault detection; propulsion; control systems; real-time systems AB An intelligent control system for reusable rocket engines is under development at the NASA Lewis Research Center, The primary objective is to extend the useful life of a reusable rocket propulsion system while minimizing flight maintenance and maximizing engine life and performance through improved control and monitoring algorithms and additional sensing and actuation, The main result of this work is the successful integration and real-time demonstration of model-based fault detection with a reconfigurable control as a nem technique for valve fault accommodation on a reusable rocket engine. The fault detection scheme detects a variety of fault modes for a valve including freezing, limiting, and leakage, However, the focus here is on detecting and accommodating a frozen (stuck in a fixed position) oxidizer valve during a down-thrust and up-thrust maneuver by examining fault parameters produced by the algorithm, The valve is selected because of its critical role in regulating the main combustion chamber mixture ratio (oxygen/fuel), The detection scheme estimates the position of the frozen valve as a function of the fault parameters, A new thrust limit is computed based on the position of the frozen valve and is used by the controller during throttling, Degraded thrust potential in a particular engine within an engine cluster can be managed at the propulsion level to meet mission requirements. Real-time simulation results demonstrate the effectiveness of the approach for two fault scenarios during a typical throttling maneuver. C1 FLORIDA ATLANTIC UNIV,BOCA RATON,FL 33431. RP Musgrave, JL (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 16 TC 7 Z9 7 U1 3 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1063-6536 J9 IEEE T CONTR SYST T JI IEEE Trans. Control Syst. Technol. PD JAN PY 1997 VL 5 IS 1 BP 100 EP 109 DI 10.1109/87.553668 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA WB875 UT WOS:A1997WB87500009 ER PT J AU Gunapala, SD Park, JS Sarusi, G Lin, TL Liu, JK Maker, PD Muller, RE Shott, CA Hoelter, T AF Gunapala, SD Park, JS Sarusi, G Lin, TL Liu, JK Maker, PD Muller, RE Shott, CA Hoelter, T TI 15-mu m 128x128 GaAs/AlxGa1-xAs quantum well infrared photodetector focal plane array camera SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID DETECTORS AB In this paper, we discuss the development of very sensitive, very long wavelength infrared GaAs/AlxGal-xAs quantum well infrared photodetectors (QWIP's) based on bound-to-quasi-bound intersubband transition, fabrication of random reflectors for efficient light coupling, and the demonstration of a 15-mu m cutoff 128 x 128 focal plane array imaging camera. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 30 mK has been achieved. C1 AMBER,GOLETA,CA 93117. RP Gunapala, SD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 12 TC 61 Z9 63 U1 0 U2 7 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 JAN PY 1997 VL 44 IS 1 BP 45 EP 50 DI 10.1109/16.554790 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA VY968 UT WOS:A1997VY96800007 ER PT J AU Gunapala, SD Liu, JK Park, JS Sundaram, M Shott, CA Hoelter, T Lin, TL Massie, ST Maker, PD Muller, RE Sarusi, G AF Gunapala, SD Liu, JK Park, JS Sundaram, M Shott, CA Hoelter, T Lin, TL Massie, ST Maker, PD Muller, RE Sarusi, G TI 9-mu m cutoff 256x256 GaAs/AlxGa1-xAs quantum well infrared photodetector hand-held camera SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article AB A 9-mu m cutoff 256 x 256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 26 mK has been achieved. In this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array and its performance in quantum efficiency, NE Delta T, minimum resolvable temperature (MRTD), uniformity, and operability. C1 AMBER,GOLETA,CA 93117. QUANTUM EPITAXIAL DESIGNS INC,BETHLEHEM,PA 18015. RP Gunapala, SD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 8 TC 91 Z9 103 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 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JAN PY 1997 VL 44 IS 1 BP 51 EP 57 DI 10.1109/16.554791 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA VY968 UT WOS:A1997VY96800008 ER PT J AU Mehregany, M Tong, LJ Matus, LG Larkin, DJ AF Mehregany, M Tong, LJ Matus, LG Larkin, DJ TI Internal stress and elastic modulus measurements on micromachined 3C-SiC thin films SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID RESIDUAL-STRESS; TRANSISTORS; SILICON AB Fabrication of epitaxial 3C-SiC microstructures by bulk micromachining of the underlying silicon substrate was investigated. Initial studies of the mechanical properties of epitaxial 3C-SiC films deposited on silicon were carried out on microstructures fabricated by bulk micromachining of the silicon substrate to evaluate the potential of these films for micromechanics. Residual stress and biaxial modulus of 3C-SiC films were measured by load-deflection measurements of suspended diaphragms. The film's residual stress was tensile with an average of 212 MPa, while the in-plane biaxial modulus averaged 441 GPa. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Mehregany, M (reprint author), CASE WESTERN RESERVE UNIV,DEPT ELECT ENGN & APPL PHYS,MICROFABRICAT LAB,CLEVELAND,OH 44106, USA. NR 31 TC 45 Z9 45 U1 1 U2 5 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 JAN PY 1997 VL 44 IS 1 BP 74 EP 79 DI 10.1109/16.554795 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA VY968 UT WOS:A1997VY96800012 ER PT J AU Khazenie, N LeToan, T AF Khazenie, N LeToan, T TI Special issue on the retrieval of bio- and geophysical parameters from SAR data for land applications - Foreword SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Editorial Material C1 CTR ETUD SPATIALES BIOSPHERE,TOULOUSE,FRANCE. RP Khazenie, N (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1997 VL 35 IS 1 BP 3 EP 3 PG 1 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WE878 UT WOS:A1997WE87800001 ER PT J AU Wegmuller, U Werner, C AF Wegmuller, U Werner, C TI Retrieval of vegetation parameters with SAR interferometry SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Symposium on Retrieval of Bio and Geophysical Parameters from SAR Data for Land Applications CY OCT 10-13, 1995 CL TOULOUSE, FRANCE SP CNES, GRSS, URSI Commission F, Electromagnet Acad, NASA, ESA DE change monitoring; land use classification; SAR interferometry AB The potential of SAR interferometric techniques for the retrieval of vegetation parameters was investigated using ERS-1 data over agricultural and forested test sites, In a first experiment an interferometrically derived forest map was generated, The classification was based on the interferometric correlation and the backscatter intensities, The result was geocoded, using the interferometrically derived height map generated from the same ERS SAR data pair, and validated with a conventional digital forest map. Forest mapping accuracies of around 90% and better were achieved, In a second experiment, multitemporal data over an agricultural site were used to investigate the potential of repeat-pass interferometry to monitor farming activity, crop development, and soil moisture variations. The interferometric correlation was used as an indicator of dense vegetation and geometric change, It was possible, for example, to identify harvesting by the high correlation of the post-harvest bare or stubble field, Decreasing interferometric correlation was observed as a consequence of crop growth. C1 CALTECH,JET PROP LAB,PASADENA,CA. RP Wegmuller, U (reprint author), GAMMA REMOTE SENSING AG,THUNSTR 130,CH-3074 MURI,BE,SWITZERLAND. NR 12 TC 116 Z9 118 U1 1 U2 10 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 JAN PY 1997 VL 35 IS 1 BP 18 EP 24 DI 10.1109/36.551930 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WE878 UT WOS:A1997WE87800003 ER PT J AU Long, DG Spencer, MW AF Long, DG Spencer, MW TI Radar backscatter measurement accuracy for a spaceborne pencil-beam wind scatterometer with transmit modulation SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE scatterometry; SeaWinds; wind measurement AB Scatterometers are remote sensing radars designed to measure near-surface winds over the ocean. The difficulties of accommodating traditional fan-beam scatterometers on spacecraft has lead to the development of a scanning pencil-beam instrument known as SeaWinds, SeaWinds will be part of the Japanese Advanced Earth Observing Satellite II (ADEOS-II) to be launched in 1999. To analyze the performance of the SeaWinds design, a new expression for the measurement accuracy of a pencil-beam system is required. In this paper we derive a general expression for the backscatter measurement accuracy for a pencil-beam scatterometer which includes the effects of transmit signal modulation with simple power detection. Both separate and simultaneous signal+noise and noise-only measurements are considered. The utility of the new expression for scatterometer design tradeoffs is demonstrated using a simplified geometry, A separate paper [8] describes detailed tradeoffs made to develop the SeaWinds design. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Long, DG (reprint author), BRIGHAM YOUNG UNIV,DEPT ELECT & COMP ENGN,PROVO,UT 84602, USA. RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 8 TC 28 Z9 31 U1 1 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 JAN PY 1997 VL 35 IS 1 BP 102 EP 114 DI 10.1109/36.551939 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA WE878 UT WOS:A1997WE87800012 ER PT J AU Spencer, MW Wu, CL Long, DG AF Spencer, MW Wu, CL Long, DG TI Tradeoffs in the design of a spaceborne scanning pencil beam scatterometer: Application to SeaWinds SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE radar; scatterometry; SeaWinds; wind measurement ID OCEAN AB SeaWinds is a spaceborne wind scatterometer to be flown on the second Japanese Advanced Earth Observing Satellite (ADEOS-II) in 1999, An important international element of NASA's earth observing system (EOS), SeaWinds is an advanced follow-on to the NASA scatterometer (NSCAT) on the first ADEOS platform, Unlike previous operational spaceborne scatterometer systems, SeaWinds employs a scanning ''pencil-beam'' antenna rather than a ''fan-beam'' antenna, making the instrument more compact and yielding greater ocean coverage, The goals of this paper are twofold, First, the overall SeaWinds functional design and backscatter measurement approach are described, and the relative advantages of the pencil-beam technique are outlined. Second, the unique aspects of measurement accuracy optimization and signal processing for the SeaWinds instrument are discussed, Applying the results of a separate companion paper [11], a technique to significantly improve measurement accuracy by modulating the transmit pulse is described, Trade-offs to optimize the transmit modulation bandwidth are presented. C1 BRIGHAM YOUNG UNIV,DEPT ELECT & COMP ENGN,PROVO,UT 84602. RP Spencer, MW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 17 TC 57 Z9 63 U1 1 U2 1 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 JAN PY 1997 VL 35 IS 1 BP 115 EP 126 DI 10.1109/36.551940 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 WE878 UT WOS:A1997WE87800013 ER PT J AU Olson, CF Huttenlocher, DP AF Olson, CF Huttenlocher, DP TI Automatic target recognition by matching oriented edge pixels SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Article ID DISTANCE; IMAGES AB This paper describes techniques to perform efficient and accurate target recognition in difficult domains, In order to accurately model small, irregularly shaped targets, the target objects and images are represented by their edge maps, with a local orientation associated with each edge pixel, Three-dimensional objects are modeled by a set of two-dimensional (2-D) views of the object, Translation, rotation, and scaling of the views are allowed to approximate full three-dimensional (3-D) motion of the object. A version of the Hausdorff measure that incorporates both location and orientation information is used to determine which positions of each object model are reported as possible target locations, These positions are determined efficiently through the examination of a hierarchical cell decomposition of the transformation space, This allows large volumes of the space to be pruned quickly. Additional techniques are used to decrease the computation time required by the method when matching is performed against a catalog of object models. The probability that this measure will yield a false alarm and efficient methods for estimating this probability at run time are considered in detail. This information can be used to maintain a low false alarm rate or to rank competing hypotheses based on their likelihood of being a false alarm, Finally, results of the system recognizing objects in infrared and intensity images are given. C1 CORNELL UNIV, DEPT COMP SCI, ITHACA, NY 14853 USA. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 22 TC 178 Z9 198 U1 2 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1057-7149 EI 1941-0042 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD JAN PY 1997 VL 6 IS 1 BP 103 EP 113 DI 10.1109/83.552100 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA WK685 UT WOS:A1997WK68500009 PM 18282882 ER PT J AU Coffey, JT Kiely, AB AF Coffey, JT Kiely, AB TI The capacity of coded systems SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE data processing; superchannel; encoder; decoder AB There are many situations in which a coding scheme is fixed for a given channel, The data processing theorem implies that the capacity of the composite channel cannot be higher than that of the original channel; usually, the capacity will be strictly lower, This paper examines the problem of how much capacity must be lost in the most common such situations, The various combinations of presence and absence of encoder and decoder, along with choice of encoder and decoder, are considered, The degree to which coding schemes can both deliver low error probability and maintain high capacity in the composite channel Is examined. C1 CALTECH,JET PROP LAB,COMMUN RES GRP,PASADENA,CA 91109. RP Coffey, JT (reprint author), UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. NR 18 TC 4 Z9 4 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 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD JAN PY 1997 VL 43 IS 1 BP 113 EP 127 DI 10.1109/18.567656 PG 15 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA WB749 UT WOS:A1997WB74900009 ER PT J AU Fixsen, D Mahler, RPS AF Fixsen, D Mahler, RPS TI The modified Dempster-Shafer approach to classification SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS LA English DT Article AB This paper describes ''modified Dempster-Shafer'' (MDS), an approach to object identification which incorporates Bayesian prior distributions into an altered Dempster-Shafer rule of combination. The MDS combination rule reduces, under strong independence assumptions, to a special case of Bayes' rule. We show that MDS has rigorous probabilistic foundations in the theory of random sets. We also demonstrate close relationships between MDS and Smets' ''pignistic'' probabilities, which in the MDS framework become true posterior distributions. We describe the application of MDS to a practical classification algorithm which uses an information-theoretic technique to limit the combinatorial explosion of evidence. We also define a non-ad hoc, MDS-based classification ''miss distance'' metric used to measure the performance of this algorithm. C1 LOCKHEAD MARTIN CORP,EAGAN,MN 55121. RP Fixsen, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,GREENBELT,MD 20771, USA. NR 31 TC 55 Z9 60 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1083-4427 J9 IEEE T SYST MAN CY A JI IEEE Trans. Syst. Man Cybern. Paart A-Syst. Hum. PD JAN PY 1997 VL 27 IS 1 BP 96 EP 104 DI 10.1109/3468.553228 PG 9 WC Computer Science, Cybernetics; Computer Science, Theory & Methods SC Computer Science GA VY961 UT WOS:A1997VY96100009 ER PT B AU Siqueira, P Chapman, B Saatchi, S Freeman, T AF Siqueira, P Chapman, B Saatchi, S Freeman, T GP IEEE TI Amazon rainforest visualization/classification by orbiting radar, enabled by supercomputers (ARVORES) SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The ARVORES project is a specific science task (part of a larger supercomputing effort) whose purpose is to develop SAR resources based on JERS-1 multi-season coverage of the Amazon rainforest using available state of the art computing technology. Because of the basin-wide coverage of this data set, in addition to providing the immediate science goals of landcover classification, it will also serve as a foundation which present and future data sets may be overlain and compared to. In addition, it is the goal of this project to use the science requirements related to the study of the Amazon region to guide the development of a flexible, large-scale computing environment for addressing SAR specific tasks. RP Siqueira, P (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 104 EP 106 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00030 ER PT B AU Haltrin, VI AF Haltrin, VI GP IEEE TI Diffuse reflectance of the optically deep sea under combined illumination of its surface SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The processing of remotely measured color imagery involves knowledge of the diffuse reflectance of the oceanic water. This paper presents two approaches to this problem. The first one is analytical and consists of an approximate solution to the radiative transfer equation. As a result it gives an equation for diffuse reflectance of the sea as a function of inherent optical properties, the sun elevation angle and the ratio of the direct illumination by sun to the diffuse illumination by sky. The second approach is a numerical Monte Carlo simulation. The results of this simulation are processed to produce regressions that connect diffuse reflectance of the seawater for different hydrooptical situations to the sun elevation angle. RP Haltrin, VI (reprint author), USN,RES LAB,OCEAN SCI BRANCH,STENNIS SPACE CTR,CODE 7331,BAY ST LOUIS,MS 39529, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 296 EP 298 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00086 ER PT B AU Haltrin, VI AF Haltrin, VI GP IEEE TI Light scattering coefficient of seawater for arbitrary concentrations of hydrosols SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The scattering coefficient of seawater as a function of concentration of hydrosol particles is calculated. The approach used is based on the Maxwell's equations in a stochastically scattering seawater. The water is modeled as thermally fluctuated medium filled with the hydrosol particles. It is found that the scattering coefficient quadratically depends on concentration when the concentration of scatterers is very small. The scattering coefficient is linear to concentration of scatterers at values typical to the open ocean. At the values of concentrations typical to coastal waters the dependence on concentration weakens and reaches the saturation at very high values. RP Haltrin, VI (reprint author), USN,RES LAB,OCEAN SCI BRANCH,STENNIS SPACE CTR,CODE 7331,BAY ST LOUIS,MS 39529, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 299 EP 301 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00087 ER PT B AU LeVine, DM Kao, M AF LeVine, DM Kao, M GP IEEE TI Effects of Faraday rotation on microwave remote sensing from space at L-band SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The effect of Faraday rotation on the remote sensing of soil moisture from space is investigated using the International Reference Ionosphere (IRI) to obtain electron density profiles and the International Geomagnetic Reference Field (IGRF) to model the magnetic field. With a judicious choice of satellite orbit (6 am, sunsynchronous) the errors caused by ignoring Faraday rotation are less than 1 K at incidence angles less than 40 degrees. RP LeVine, DM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,CODE 975,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 377 EP 379 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00109 ER PT B AU Jin, MY AF Jin, MY GP IEEE TI High quality spotlight SAR processing algorithm - Designed for LightSAR mission SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB A high quality spotlight SAR processing algorithm is presented. In this algorithm, subband images of the radar illuminated spot are processed using well known strip mode processing algorithms. A full resolution image is then formed by (1) merging the spectra of subband images into a full band spectrum, and (2) taking an Inverse FFT. Advantages of this algorithm include (1) higher image quality, (2) higher processing throughput rate, and (3) lower S/W development cost. The image quality achieved by this algorithm is better than that previously achieved by the backprojection algorithm. The fine image quality is demonstrated by the SIR-C spotlight SAR images. RP Jin, MY (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 300-243,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 477 EP 480 PG 4 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00138 ER PT B AU Schoeberl, MR Douglass, AR Jackman, CH AF Schoeberl, MR Douglass, AR Jackman, CH GP IEEE TI A summary of the Upper Atmosphere Research Satellite (UARS) SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The UARS satellite has been operating for six years and has gathered an unprecedented amount of data on the stratosphere. The most significant findings from UARS are associated with the mapping of the polar ozone depletions sold the observations of the long term trends in chlorine gases in the stratosphere. RP Schoeberl, MR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Douglass, Anne/D-4655-2012; Jackman, Charles/D-4699-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 542 EP 544 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00155 ER PT B AU Foster, JL Hall, DK Chang, ATC Rango, A Wergin, W Erbe, E AF Foster, JL Hall, DK Chang, ATC Rango, A Wergin, W Erbe, E GP IEEE TI Snow crystal shape and microwave scattering SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Foster, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,LAB HYDROL PROC,CODE 974,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 625 EP 627 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00177 ER PT B AU Khazenie, N Stockman, S AF Khazenie, N Stockman, S GP IEEE TI NASA's mission to planet earth invests in the future through a broad national education program SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB NASA's Mission to Planet Earth Program (MTPE) is a long-term research program to examine the global effects of human-induced and natural influences on the Earth's interacting physical, biological, and chemical systems. MTPE's Earth Observing System (EOS) is a comprehensive system which consists of a set of Earth-observing instruments on spacecraft and in situ to collect the data needed for the research, and a data and information system to process, store, distribute, and make accessible the acquired instrument data. While the most significant and visible goal of MTPE is increased scientific understanding, education, in its broadest form, has become an extremely important part of the program, and is embedded in our goals and success criteria. One goal of the MTPE program is to ''foster the development of an informed and environmentally aware public.'' Within this context, contributions by MTPE to the advancement of formal education are a major aspect of how the success of the program will be measured. The MTPE educational programs and resources are designed with the following objectives: 1) train next generation of scientists to use an interdisciplinary, Earth system science approach; 2) continue to educate and train educators as research evolves and capabilities change; 3) raise awareness of policy makers and citizens to enable prudent policy determination regarding global change; 4) improve science and math literacy; 5) improve interface between educators and scientists; 6) explore mechanisms to leverage the development of materials; and 7) educate the populace to be better caretakers of Earth for future generations. As a response to the above objectives several key national educational programs have been identified and implemented. These include: 1) Teacher Preparation Programs; 2) Curriculum Support Materials Development; 3) Systemic Change - US Global Change Education Workshops; and 4) Global Learning and Observations to Benefit the Environment (GLOBE). RP Khazenie, N (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MISSION PLANET EARTH PROGRAM OFF,CODE 170,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 685 EP 687 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00197 ER PT B AU Kahn, R AF Kahn, R GP IEEE TI Practical uses of math and science (PUMAS) SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Meeting Abstract CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Kahn, R (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 169-237,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 698 EP 698 PG 1 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00201 ER PT B AU Comiso, JC Zwally, HJ AF Comiso, JC Zwally, HJ GP IEEE TI Temperature corrected bootstrap algorithm SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB A temperature corrected Bootstrap Algorithm has been developed using Nimbus-7 Scanning Multichannel Microwave Radiometer data in preparation to the upcoming AMSR instrument aboard ADEOS and EOS-PM The procedure first calculates the effective surface emissivity using emissivities of ice and water at 6 GHz and a mixing formulation that utilizes ice concentrations derived using the current Bootstrap algorithm but using brightness temperatures from 6 GHz and 37 GHz channels. These effective emissivities are then used to calculate surface ice temperatures which in turn are used to convert the 18 GHz and 37 GHz brightness temperatures to emissivities. Ice concentrations are then derived using the same technique as with the Bootstrap algorithm but using emissivities instead of brightness temperatures. The results show significant improvements in areas where ice temperature is expected to vary considerably such as near the continental areas in the Antarctic, where the ice temperature is colder than average, and in marginal ice-zones. RP Comiso, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,CODE 971,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 857 EP 861 PG 5 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00252 ER PT B AU Yanow, G Herzog, A AF Yanow, G Herzog, A GP IEEE TI Project SUN (students understanding nature) SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Yanow, G (reprint author), NASA,JET PROPULS LAB,4800 OAK GROVE DR,MAIL STOP CS-530,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 951 EP 953 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00280 ER PT B AU Skiles, JW Kennedy, KD Rundberg, WB Peterson, DL AF Skiles, JW Kennedy, KD Rundberg, WB Peterson, DL GP IEEE TI Using the World Wide Web for distributed learning: Two examples SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB This paper details two projects that use the World Wide Web (WWW) for dissemination of curricula that focus on remote Sensing. 1) Presenting grade-school students with the concepts used in remote sensing involves educating the teacher and then providing the teacher with lesson plans. In a NASA-sponsored project designed to introduce students in grades 4 through 12 to some of the ideas and terminology used in remote sensing, teachers from local grade schools and middle schools were recruited to write lessons about remote sensing concepts they could use in their classrooms. Twenty-two lessons were produced and placed in seven modules that include: the electromagnetic spectrum, two-and three-dimensional perception, maps and topography, scale, remote sensing, biotic and abiotic concepts, and landscape change. Each lesson includes a section that evaluates what students have learned by doing the exercise. The lessons, instead of being published in a workbook and distributed to a limited number of teachers, have been placed on a WWW server, enabling much broader access to the package. This arrangement also allows for the lessons to be modified after feedback from teachers accessing the package. 2) Two-year colleges serve to teach trade skills, prepare students for enrollment in senior institutions of learning, and more and more, re-train students who have college degrees in new technologies and skills. A NASA-sponsored curriculum development project is producing a curriculum using remote sensing analysis and Earth science applications. The project has three major goals. First, it will implement the use of remote sensing data in a broad range of community college courses. Second it will create curriculum modules and classes that are transportable to other community colleges. Third, the project will be an ongoing source of data and curricular materials to other community colleges. The curriculum will have these course pathways to a certificate; a) a Science emphasis, b) an Arts and Letters emphasis, and c) a Computer Science emphasis. Each pathway includes course work in remote sensing, geographical information systems (GIS), computer science, Earth science, software and technology utilization, and communication. Distribution of products from this project to other two-year colleges will be accomplished using the WWW. RP Skiles, JW (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV,MAIL STOP 239-20,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 957 EP 959 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00282 ER PT B AU Yanow, G AF Yanow, G GP IEEE TI ''Winds of change'', the NSCAT CD-ROM SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Yanow, G (reprint author), NASA,JET PROPULS LAB,EDUC AFFAIRS OFF,4800 OAK GROVE DR,MAIL STOP CS-530,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 960 EP 962 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00283 ER PT B AU Hilliard, L Jenstrom, D Chesters, D Racette, P AF Hilliard, L Jenstrom, D Chesters, D Racette, P GP IEEE TI Geosynchronous technology infusion studies SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB NASA and NOAA are now sponsoring Advanced Geosynchronous Studies (AGeoS), technology work that will lead to the next generation of space sensors located in geosynchronous orbit. RP Hilliard, L (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 984 EP 986 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00291 ER PT B AU Mattikalli, NM Engman, ET Jackson, TJ AF Mattikalli, NM Engman, ET Jackson, TJ GP IEEE TI Microwave remote sensing of soil moisture for estimation of soil properties SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Surface soil moisture dynamics was derived using microwave remote sensing, and employed to estimate soil physical and hydraulic properties. The L-band ESTAR radiometer was employed in an airborne campaign over the Little Washita watershed, Oklahoma during June 10-18, 1992. Brightness temperature (TB) data were employed in a soil moisture inversion algorithm which corrected for vegetation and soil effects. Analyses of spatial TB and soil moisture dynamics during the dry-down period revealed a direct relationship between changes in TB, soil moisture and soil texture. Extensive regression analyses were carried out which yielded statistically significant quantitative relationships between ratio of percent sand to percent clay (RSC, a term derived to quantify soil texture) and saturated hydraulic conductivity (Ksat) in terms of change components of TB and surface soil moisture. Validation of results indicated that both RSC and Ksat can be estimated with reasonable accuracy. These findings have potential applications for deriving spatial distributions of RSC and Ksat over large areas. RP Mattikalli, NM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,HYDROL SCI BRANCH,CODE 974,HUGES STX,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1093 EP 1095 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00326 ER PT B AU Lakshmi, V Susskind, J AF Lakshmi, V Susskind, J GP IEEE TI Land surface hydrological processes using satellite data SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Field experiments designed to support climate studies are of limited spatial and temporal coverage. Satellite data bridges the gap between field experiments and large scale modeling by aiding in model validation. The Tires Operational Vertical Sounder (TOVS) Pathfinder Path A surface data of surface skin temperature, surface air temperature and the relative humidity will be used for the Red River Basin grid box in the GCIP LSA-SW region to simulate the surface fluxes, surface skin temperature and surface soil moisture. The surface skin temperatures simulated and observed by the TOVS will be compared. RP Lakshmi, V (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 9104,GREENBELT,MD 20771, USA. RI Lakshmi, Venkat/I-3078-2016 OI Lakshmi, Venkat/0000-0001-7431-9004 NR 0 TC 2 Z9 2 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1102 EP 1104 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00329 ER PT B AU Fishtahler, LE AF Fishtahler, LE GP IEEE TI Standard data products from the MODIS science team SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Fishtahler, LE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1249 EP 1251 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00377 ER PT B AU Ziskin, DC Chan, P AF Ziskin, DC Chan, P GP IEEE TI Innovations in response to floods of data SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The good news is that the Earth Science community will not be data-starved in the Earth Observing System (EOS) era. The bad news is that techniques to cope with enormous volumes of Earth Science data have not yet met the challenge. Coping with data involves processes such as becoming familiar with a data center's inventory, searching for appropriate data, and retrieving only the data that are needed. The Center for Earth Observations and Space Research (CEOSR) of George Mason University, in partnership with the NASA Goddard Distributed Active Archive Center (DAAC), have developed some innovations to reduce barriers that users may experience in accessing Earth Science data. The techniques are extensions of two fundamental concepts: Data distribution must become responsive to data users' needs, and statistical summaries of data stored as metadata can provide a basis for content-based data selection. RP Ziskin, DC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DISTRIBUTED ACT ARCH CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1255 EP 1256 PG 2 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00379 ER PT B AU Hsu, AY ONeill, PE Wood, EF Zion, M AF Hsu, AY ONeill, PE Wood, EF Zion, M GP IEEE TI Examination of soil moisture retrieval using SIR-C radar data and a distributed hydrological model SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Hsu, AY (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SSAI,CODE 974,GREENBELT,MD 20771, USA. OI Wood, Eric/0000-0001-7037-9675 NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1266 EP 1268 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00383 ER PT B AU Comiso, JC Stock, L AF Comiso, JC Stock, L GP IEEE TI Antarctic surface temperatures using satellite infrared data from 1979 through 1995 SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB The large scale spatial and temporal variations of surface ice temperature over the Antarctic region are studied using infrared data derived from the Nimbus-7 Temperature Humidity Infrared Radiometer (THIR) from 1979 through 1985 and from the NOAA Advanced Very High Resolution Radiometer (AVHRR) from 1984 through 1995. Enhanced techniques suitable for the polar regions for cloud masking and atmospheric correction were used before converting radiances to surface temperatures. The observed spatial distribution of surface temperature is highly correlated with surface ice sheet topography and agrees well with ice station temperatures with 2K to 4K standard deviations. The average surface ice temperature over the entire continent fluctuates by about 30K from summer to winter while that over the Antarctic Plateau varies by about 45K. Interannual fluctuations of the coldest temperatures are observed to be as large as 15K. Also, the interannual variations in surface temperatures are highest at the Antarctic Plateau and the ice shelves (e.g., Ross and Ronne) with a periodic cycle of about 5 years and standard deviations of about 11K and 9K, respectively. Despite large temporal variability, however, especially in some regions, a regression analysis that includes removal of the seasonal cycle shows no apparent trend in temperature during the period 1979 through 1995. RP Comiso, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,CODE 971,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1300 EP 1304 PG 5 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00394 ER PT B AU VanZyl, JJ Chu, AH Hensley, S Lou, YL Kim, YJ Madsen, SN AF VanZyl, JJ Chu, AH Hensley, S Lou, YL Kim, YJ Madsen, SN GP IEEE TI The AIRSAR/TOPSAR integrated multi-frequency polarimetric and interferometric SAR processor SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP VanZyl, JJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1358 EP 1360 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00411 ER PT B AU Lou, Y Kim, Y vanZyl, J Maldonado, L Miller, T OLeary, E Romero, G Skotnicki, W Taylor, V AF Lou, Y Kim, Y vanZyl, J Maldonado, L Miller, T OLeary, E Romero, G Skotnicki, W Taylor, V GP IEEE TI The NASA/JPL Airborne Synthetic Aperture Radar's 1996 PacRim deployment SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB In November and December 1996, the NASA/JPL Airborne Synthetic Aperture Radar system (AIRSAR) embarked on a seven-week campaign to several Pacific Rim countries. This mission was jointly organized by NASA, Australia's Office of Space Science and Application, and University of New South Wales. The major purpose of the mission is to establish a collaborative effort in the area of radar remote sensing application between the United States and the Pacific Rim countries. SAR data were acquired for both U.S. researchers as well as the participating countries. In addition to Hawaii, we imaged areas of interest in New Zealand, Australia, Papua New Guinea, Malaysia, Brunei, the Philippines, Taiwan, Thailand, and Cambodia including coastal regions of some countries. The target areas of this multi-frequency, polarimetric and interferometric SAR system included volcanoes, sites for studies in geology, hydrology, and landuse mapping, and forested mountains to generate height maps of rugged and inaccessible areas. RP Lou, Y (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 300-243,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1404 EP 1406 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00425 ER PT B AU Liu, WT AF Liu, WT GP IEEE TI Observation of global ocean-atmosphere exchanges from spaceborne sensors SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Liu, WT (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1435 EP 1437 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00435 ER PT B AU Lau, WKM AF Lau, WKM GP IEEE TI Water vapor and cloud feedback mechanisms: Inferences from satellite observations and numerical modeling SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Satellite observations show large sensitivity of water vapor and cloud forcings to sea surface temperature changes during major climate events such as the El Nine Southern Oscillation (ENSO). This lead to two very important questions: What are the mechanisms of the observed large sensitivity? and can we use ENSO as a surrogate to understand mechanisms for climate change? This paper addresses the above questions. We have studied the sensitivity of water vapor and cloud forcings to ocean temperature changes and their relationship with large scale circulation regimes using AVHRR and ERBE satellite outgoing longwave radiation, sea surface temperature and large scale circulation data. Results show that on interannual time scales, changes in the large scale circulation regimes contribute substantially to anomalies in the water vapor and cloud forcing observed during major climate events such as ENSO. Experiments show that over 75% of the observed apparent sensitivity of water vapor and cloud feedback sensitivity are due to changes in the large scale circulation with direct radiative feedback accounting for less than 20% of the observed changes. On interannual time scales, when adjustments are made for changes in the large scale circulation, the so-called supergreenhouse effect, i.e., run away greenhouse warming, does not exist. The results point to possible pitfalls in interpreting results for cloud and radiation feedback processes and that ENSO or other natural climate variations such as the seasonal cycle cannot simply be used as a surrogates for climate change without taking into account the effect of large scale dynamics. RP Lau, WKM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CLIMATE & RADIAT BRANCH,CODE 913,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 0 TC 0 Z9 0 U1 0 U2 2 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1438 EP 1440 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00436 ER PT B AU Liu, AK Wu, SY Tseng, WY AF Liu, AK Wu, SY Tseng, WY GP IEEE TI Wavelet analysis of satellite images for coastal monitoring SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB In this paper, algorithms and techniques for automated detection and tracking of mesoscale features from satellite imagery employing wavelet analysis are presented. The wavelet transform has been applied to satellite images, such as those from Synthetic Aperture Radar (SAR), Advanced Very High-Resolution Radiometer (AVHRR), and Coastal Zone Color Scanner (CZCS) for feature extraction and Special Sensor Microwave/Imager (SSM/I) data for sea ice drift. The evolution of mesoscale features such as oil slicks, fronts, eddies, and ice floes/textures can be tracked by the wavelet analysis using satellite data from repeating paths. RP Liu, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 971,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1441 EP 1443 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00437 ER PT B AU Cahalan, RF Davis, A Marshak, A Silberstein, D Wiscombe, W AF Cahalan, RF Davis, A Marshak, A Silberstein, D Wiscombe, W GP IEEE TI Cloud macrostructure and radiation SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Cloud radiative properties are sensitive not only to drop size and other parameters of cloud micro-structure, but also cloud shape, spacing, other parameters of cloud macro-structure. Field programs such as DoE/ARM and DoE/UAV are now underway to improve the measurement and modelling of physical and radiative properties of clouds under a variety of meteorological. conditions. A parallel effort is underway to improve cloud remote sensing from current GOES and AVHRR platforms as well as the upcoming NASA suite of EOS instrument which will provide higher spectral and/or spatial resolution, such as MODIS and ETM+/LATI. Corrections to plane-parallel theory to account for cloud inhomogeneity take different forms for the 100 km scale of climate model grids, and for the 1 km scale of typical satellite pixels. A first approximation for grid-scale fluxes is obtained by a linear weighting of clear clear and cloudy fractions, using an ''effective cloud thickness'' which depends on the within-cloud variability. A key finding for improving pixel-scale retrievals is that there is a characteristic ''radiative smoothing'' scale of several hundred meters. This scale has been observed as a change in the spatial spectrum of Landsat cloud radiances, and was also recently found with the help of Spinhirne's lidar at NASA-Goddard, by searching for returns from directions nonparallel to the incident beam. ''Offbeam'' Lidar returns are now being used to estimate the cloud ''Green's function'', which will be applied to improving simple IPA estimates of cloud radiative properties. This and other measurements of 3D transfer in clouds, coupled with 30 Monte Carlo transfer methods, are beginning to provide a better understanding of the dependence of radiation on cloud inhomogeneity, and to suggest new retrieval and parameterization algorithms which fake account of cloud inhomogeneity. RP Cahalan, RF (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 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1444 EP 1447 PG 4 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00438 ER PT B AU Tsay, SC AF Tsay, SC GP IEEE TI Global monitoring and retrievals of atmospheric aerosols and clouds SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB A knowledge of aerosol and cloud radiative properties and their variation in space and time is especially crucial to the understanding of the radiative forcing in all climate related studies. The role of clouds in modifying the Earth's radiation balance - albedo cooling effect in short-wave radiation and greenhouse warming effect in longwave radiation - is well recognized as a key source of uncertainty. Man-made processes, both burning of fossil fuels and biomass, generate greenhouse gases and aerosol particles. Directly, aerosol particles can scatter and absorb the sun light. Indirectly, these particles may serve as cloud condensation nuclei and alter cloud albedo. Ship tracks have provided intriguing examples of cloud albedo modification by anthropogenic aerosols. There has been a general concern that the potential climate forcing from the indirect effects of aerosol on clouds can be of comparable magnitude, but opposite in sign, to greenhouse gas radiative forcing. Global monitoring of aerosol and cloud radiative effects relies on advanced Earth Observing Systems (e.g., NASA's EOS and NASDA's ADEOS). Key advances include simultaneous observation of radiation budget and aerosol/cloud properties, additional information on particle size, phase, and vertical layer structure. Comprehensive radiation models are used to develop retrieval algorithms. This paper presents an overview of the science and technique in remote sensing and retrievals of atmospheric aerosols and clouds. High quality multi-spectral imagery, together with nadir propagating lidar measurements, acquired from high altitude aircraft in many field experiments ale served as examples for discussion. RP Tsay, SC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CLIMATE & RADIAT BRANCH,CODE 913,GREENBELT,MD 20771, USA. RI Tsay, Si-Chee/J-1147-2014 NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1448 EP 1450 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00439 ER PT B AU Imhoff, ML Milne, AK Sisk, TD Lawrence, WT Brennan, K AF Imhoff, ML Milne, AK Sisk, TD Lawrence, WT Brennan, K GP IEEE TI Mapping vegetation structure for biodiversity analysis using synthetic aperture radar SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB An integrated remote sensing/field ecology project was carried out to link the use of synthetic aperture radar (SAR) and other remotely sensed data to studies of landscape spatial heterogeneity and bird community ecology as a first step toward applications in predicting biodiversity. P-, L-, and C-band SAR data were collected over a section of the South Alligator River in Kakadu National Park in Australia's Northern Territory as part of the Joint NASA/Australia DC-8 AIRSAR data acquisition campaign in 1993 and the NASA/PACRIM AIRSAR deployment in 1996. The SAR data were analyzed with field data integrating vegetation structure and floristics with bird abundances across a heterogeneous study site that spanned several abrupt habitat edges. Results indicate that SAR data are able to discern structural differences relevant to bird habitat quality within floristically homogeneous stands, while multispectral sensors successfully identified floristic differences among habitat types. RP Imhoff, ML (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1624 EP 1626 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00496 ER PT B AU Durden, SL Haddad, ZS Kitiyakara, A Li, FK AF Durden, SL Haddad, ZS Kitiyakara, A Li, FK GP IEEE TI Effect of non-uniform beam-filling on TRMM PR rainfall measurements SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB We investigate effects of non-uniform beam-filling on TRMM PR rain retrieval using data from the NASA/JPL Airborne Rain MApping Radar (ARMAR) acquired during TOGA COARE, in early 1993. Our approach is to simulate TRMM PR observations using the ARMAR data and compare the radar observables and retrieved rain rate from the simulated PR data with those corresponding to the high-resolution radar measurements. RP Durden, SL (reprint author), CALTECH,JET PROP LAB,JPL 300 235,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1639 EP 1641 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00501 ER PT B AU Haddad, ZS Durden, SL Im, E AF Haddad, ZS Durden, SL Im, E GP IEEE TI Bayesian fusion of TRMM passive and active measurements SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB a Bayesian method was adopted to combine the instantaneous measurements of the Tropical Rainfall Measuring Mission (TRMM)'s radar and radiometer ([4]). The method makes multiple estimates of the rain-rate profile using the radar reflectivities assuming various plausible values for the drop size distribution (DSD) shape parameters, then selects those parameter values which produce estimates that are most consistent with the passive observations. The resulting estimates are expressed directly in terms of the DSD parameters, thus allowing one to calculate any rain-related quantity, such as rain rate profile, precipitating liquid water profile, etc. The Bayesian approach also allows one to calculate the ''error bar'' associated with each estimate. RP Haddad, ZS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1642 EP 1644 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00502 ER PT B AU Ranson, KJ Sun, G AF Ranson, KJ Sun, G GP IEEE TI Effect of environmental temperatures on SAR forest biomass estimates. SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB This paper discusses the observed effects of temperature conditions on estimates of forest biomass in a portion of the Canadian boreal forest. Biomass estimation equations were developed from relationships between SAR backscatter and measured forest biomass for several forest stands. Separate relationships were developed for SAR images acquired under widely different temperature conditions. The biomass estimates obtained from the different images were compared. Differences in observed backscatter behavior and biomass results are discussed. RP Ranson, KJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1722 EP 1724 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00528 ER PT B AU Wang, JR Racette, P AF Wang, JR Racette, P GP IEEE TI Airborne millimeter-wave radiometric observations of cirrus clouds SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB This paper reports the first radiometric measurements of cirrus clouds in the frequency range of 89-325 GHz from a high-altitude aircraft flight. The measurements are conducted with a Millimeter-wave Imaging Radiometer (MIR) on board the NASA ER-2 aircraft over a region in northern Oklahoma. Aboard the same aircraft are a cloud lidar system and a multichannel radiometer operating at the visible and infrared wavelengths. The instrument ensemble is well suited for identifying cirrus clouds. It is shown that the depressions in brightness temperatures associated with a few intense cirrus clouds occur at all frequency channels of the MIR. Estimates of total ice water path of the cirrus clouds are derived from comparisons of radiative transfer calculations and observed brightness depressions. RP Wang, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1737 EP 1739 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00533 ER PT B AU Winker, DM AF Winker, DM GP IEEE TI Application of space lidar to the remote sensing of clouds and aerosols SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Clouds and aerosols have important influences on the climate and remote sensing from space is required to assess their effects on a global scale. Current capabilities to observe clouds and aerosols using passive satellite sensors are limited, however. The Lidar In-space Technology Experiment, flown on the space shuttle in September 1994, demonstrated the application of space lidar to the study of clouds and aerosols. Lidar technology has now matured to a point where satellite lidars are feasible. Space lidar will provide new measurement capabilities and provide improved detection and characterization of the role of aerosol and cloud in global climate. RP Winker, DM (reprint author), NASA,LANGLEY RES CTR,MS-475,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1740 EP 1742 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00534 ER PT B AU Conel, JE Ledeboer, WC Pilorz, SH Martonchik, JV Kahn, R Abdou, W Bruegge, C Helmlinger, MC Gaitley, BJ AF Conel, JE Ledeboer, WC Pilorz, SH Martonchik, JV Kahn, R Abdou, W Bruegge, C Helmlinger, MC Gaitley, BJ GP IEEE TI Ground-based validation of the EOS Multi-angle Imaging SpectroRadiometer (MISR) aerosol retrieval algorithms and science data products SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB A plan for the ground-based validation of MISR aerosol retrieval is outlined. Activities occur in two phases: (1) pre-launch, work is focused on technique development and MISR algorithm validation using conventional groundbased methods and a MISR simulator (AirMISR) operating from the ER-2 aircraft to simulate MISR on-orbit observations. (2) Post-launch, the validation program relies on ground campaigns, underflights with the MISR simulator and the use of local measurements of aerosol loading and properties and irradiance measurements derived from the AERONET and ISIS networks. RP Conel, JE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 169-237,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1743 EP 1748 PG 6 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00535 ER PT B AU Moghaddam, M Saatchi, S Treuhaft, R AF Moghaddam, M Saatchi, S Treuhaft, R GP IEEE TI Estimating soil moisture in a boreal old jack pine forest SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB Polarimetric L-and P-band AIRSAR data, corresponding model simulations, and classification algorithms have shown that in a boreal old jack pine (OJP) stand, the principal scattering mechanism responsible for radar backscatter is the double-bounce mechanism between the tree trunks and the ground [1]. The data to be used here were taken during six flights from April to September 1994 as part of the BOREAS project. The dielectric constants, or equivalently moisture contents, of the trunks and soil, can change rapidly during this period. To estimate these dynamic unknowns, parametric models of observed radar backscatter for the double-bounce mechanism are developed by using a series of simulations of a numerical forest scattering model. The resulting simulated data are used to derive polynomial fits of backscattering cross section as a function of the ground and trunk dielectric constants. Empirical and field data are used to relate the real and imaginary parts of the dielectric constants, and hence formulate the parametric model in terms of two unknowns only. Three data channels, P-HH, P-VV, and L-HH are used to solve of the two unknowns. A nonlinear optimization procedure is used to estimate the dielectric constants, and hence, in particular, soil moisture. Point ground measurements are used to verify the results of the estimation algorithm. RP Moghaddam, M (reprint author), CALTECH,JET PROP LAB,MS 300 235,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1881 EP 1883 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00579 ER PT B AU Treuhaft, RN Moghaddam, M Yoder, BJ AF Treuhaft, RN Moghaddam, M Yoder, BJ GP IEEE TI Forest vertical structure from multibaseline interferometric radar for studying growth and productivity SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB This paper describes the first quantitative attempt to estimate the vertical profile characteristics of forests from multibaseline interferometric radar (INSAR) data. In order to calculate the accuracy with which vertical characteristics can be estimated with INSAR, a simple, two-layer (sucanopy and canopy) forest is assumed to be observed by 4 baselines, most of which can be realized by current airborne systems. Calculations suggest that the height of the subcanopy layer, the total height of the forest, and the altitude of the underlying surface can be estimated with accuracies of 2-4 meters, with multiple baselines at C-band (wave length=0.056 cm). Extinction coefficients of each layer can be estimated with accuracies of 0.1 db/m. The estimation of height and extinction parameters from INSAR data is nonlinear, and accuracies therefore may depend heavily on the actual characteristics of the observed forest. This paper also discusses the application of vertical profile information estimated from INSAR to the identification of old-growth forests and their characteristics of growth and productivity. Because old-growth forests are characterized by layered vertical structures, the subanopy and canopy characteristics discussed in this paper may enable identification and monitoring of old-growth stands, which in turn would facilitate ecosystem management and assessment of primary production on a global scale. RP Treuhaft, RN (reprint author), CALTECH,JET PROP LAB,MS 300 325,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1884 EP 1886 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00580 ER PT B AU Wang, JR Racette, P Triesky, ME Browell, EV Ismail, S Chang, LA AF Wang, JR Racette, P Triesky, ME Browell, EV Ismail, S Chang, LA GP IEEE TI Simultaneous measurements of water vapor profiles from airborne MIR and LASE SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci AB A NASA ER-2 aircraft flight with both Millimeter-wave Imaging radiometer (MIR) and Lidar Atmospheric Sensing Experiment (LASE) was made over ocean areas in the eastern United States on September 25, 1995. The water vapor profiles derived from both instruments under both clear and cloudy conditions are compared in this paper. It is shown that good agreement is found between the MIR-derived and the LASE-measured water vapor profiles over the areas of clear-sky condition. In the cloudy areas, the MIR-retrieved values at the altitudes of the cloud layers and below are generally higher than those measured by the LASE. RP Wang, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 1969 EP 1971 PG 3 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00608 ER PT B AU Liu, WT AF Liu, WT GP IEEE TI Studies of atmospheric and oceanic phenomena with the NASA scatterometer SO IGARSS '97 - 1997 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM, PROCEEDINGS VOLS I-IV: REMOTE SENSING - A SCIENTIFIC VISION FOR SUSTAINABLE DEVELOPMENT LA English DT Proceedings Paper CT 1997 International Geoscience and Remote Sensing Symposium (IGARSS 97) on Remote Sensing - A Scientific Vision for Sustainable Development CY AUG 03-08, 1997 CL SINGAPORE, SINGAPORE SP IEEE Geosci & Remote Sensing Soc, Natl Univ Singapore, Ctr Remote Imaging Sensing & Proc, NASA, NOAA, USN, Off Naval Res, Int Union Radio Sci RP Liu, WT (reprint author), CALTECH,JET PROP LAB 300 323,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3837-5 J9 INT GEOSCI REMOTE SE PY 1997 BP 2082 EP 2083 PG 2 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BJ48Y UT WOS:A1997BJ48Y00645 ER PT S AU Beye, R George, T Yang, JW Khan, MA AF Beye, R George, T Yang, JW Khan, MA BE Ponce, FA Moustakas, TD Akasaki, I Monemar, BA TI A microstructural analysis of orientation variation in epitaxial AlN on Si, its probable origin, and effect on subsequent GaN growth SO III-V NITRIDES SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on III-V Nitrides CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc, AIXTRON MORITANI, Matsushita Elect Ind Co Ltd, Cent Res Labs, Cree Res, Fujitsu Ltd, Hewlett Packard Labs Japan Inc, Hitachi Ltd, Cent Res Lab, JEOL US Inc, USN, Off Naval Res, NEC Corp, Opto Electr Res Labs, Nichia Chem Ind Ltd, Renishaw, Rockwell Int Corp, Sharp Corp Cent Res Labs, Sony Corp Res Ctr, Toyoda Gosei Co Ltd, Xerox Palo Alto Res Ctr AB A structural examination of aluminum nitride growth on [111] silicon was carried out using transmission electron microscopy. Electron diffraction indicates that the basal planes of the wurtzitic overlayer mimic the orientation of the close-packed planes of the substrate. However, considerable, random rotation in the basal plane and random out of plane tilts of about +/-3-4 degrees are evident. The orientation variations were traced to the Si interface, where crystallites and an amorphous-like background were present. A strong relationship between these phenomena and substrates containing Si is established by comparing the present growth results with those reported elsewhere. Crystalline quality of the overgrown GaN on the AIN layer is described, with suggestions for the relation between surface pyramids or peaks and the mis-oriented buffer layer. RP Beye, R (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-353-3 J9 MATER RES SOC SYMP P PY 1997 VL 449 BP 113 EP 118 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BH46L UT WOS:A1997BH46L00017 ER PT S AU Huang, ZC Mott, DB Shu, PK Zhang, R Chen, JC Wickenden, DK AF Huang, ZC Mott, DB Shu, PK Zhang, R Chen, JC Wickenden, DK BE Ponce, FA Moustakas, TD Akasaki, I Monemar, BA TI Optical quenching of photoconductivity in GaN photo-conductors SO III-V NITRIDES SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on III-V Nitrides CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc, AIXTRON MORITANI, Matsushita Elect Ind Co Ltd, Cent Res Labs, Cree Res, Fujitsu Ltd, Hewlett Packard Labs Japan Inc, Hitachi Ltd, Cent Res Lab, JEOL US Inc, USN, Off Naval Res, NEC Corp, Opto Electr Res Labs, Nichia Chem Ind Ltd, Renishaw, Rockwell Int Corp, Sharp Corp Cent Res Labs, Sony Corp Res Ctr, Toyoda Gosei Co Ltd, Xerox Palo Alto Res Ctr AB We report the first observation of optical quenching of photoconductivity in GaN photoconductors at room temperature. Three prominent quenching bands were found at E(V)+1.44, 1.58 and 2.20 eV, respectively. These levels are related to the three hole traps in GaN materials based on a hole trap model to interpret the quenching mechanism. The responsivity was reduced about 12% with an additional He-Ne laser shining on the detector. RP Huang, ZC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SOLID STATE DEVICE DEV BRANCH,CODE 718,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-353-3 J9 MATER RES SOC SYMP P PY 1997 VL 449 BP 799 EP 804 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BH46L UT WOS:A1997BH46L00121 ER PT S AU Freed, M Remington, R AF Freed, M Remington, R BE Pollack, ME TI Managing decision resources in plan execution SO IJCAI-97 - PROCEEDINGS OF THE FIFTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 AND 2 SE INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE LA English DT Proceedings Paper CT 15th International Joint Conference on Artificial Intelligence CY AUG 23-29, 1997 CL NAGOYA, JAPAN SP Int Joint Conf Artificial Intelligence Inc, Japanese Soc Artificial Intelligence AB We describe an approach to the problem of managing resources in routine decision-making tasks. The central feature of this approach is the use of reusable RAP-like plans to generate decisions. This allows our system, APEX, to take advantage of the flexibility in scheduling and method selection provided by execution mechanisms and thereby minimize or circumvent resource conflicts, We then discuss an application of APEX for simulating a human air traffic controller in order to aid in the evaluation of radar display designs. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Freed, M (reprint author), NASA, Ames Res Ctr, MS 262-2, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA SN 1045-0823 BN 1-55860-480-4 J9 INT JOINT CONF ARTIF PY 1997 BP 322 EP 326 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BK59Y UT WOS:000072707200048 ER PT S AU Frank, J AF Frank, J BE Pollack, ME TI Learning short-term weights for GSAT SO IJCAI-97 - PROCEEDINGS OF THE FIFTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 AND 2 SE INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE LA English DT Proceedings Paper CT 15th International Joint Conference on Artificial Intelligence CY AUG 23-29, 1997 CL NAGOYA, JAPAN SP Int Joint Conf Artificial Intelligence Inc, Japanese Soc Artificial Intelligence AB We investigate an improvement to GSAT which associates a weight with each clause. We change the objective function so that GSAT moves to assignments maximizing the weight of satisfied clauses, and each clause's weight is changed when GSAT moves to an assignment in which this clause is unsatisfied. We present results showing that this version of GSAT has good performance when clause weights are. reduced geometrically throughout the course of a single try. We conclude that clause weights are best interpreted as short-term, context sensitive indicators of low hard different clauses are to satisfy. C1 NASA, Ames Res Ctr, Caelum Res Corp, Moffett Field, CA 94035 USA. RP Frank, J (reprint author), NASA, Ames Res Ctr, Caelum Res Corp, Mail Stop 269-2, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA SN 1045-0823 BN 1-55860-480-4 J9 INT JOINT CONF ARTIF PY 1997 BP 384 EP 389 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BK59Y UT WOS:000072707200057 ER PT S AU Williams, BC Nayak, PP AF Williams, BC Nayak, PP BE Pollack, ME TI A reactive planner for a model-based executive SO IJCAI-97 - PROCEEDINGS OF THE FIFTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 AND 2 SE INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE LA English DT Proceedings Paper CT 15th International Joint Conference on Artificial Intelligence CY AUG 23-29, 1997 CL NAGOYA, JAPAN SP Int Joint Conf Artificial Intelligence Inc, Japanese Soc Artificial Intelligence AB A new generation of reactive, model-based executives are emerging that make extensive use of component-based declarative models to analyze anomalous situations and generate novel sequences for the internal control of complex autonomous systems. Burton, a generative, model-based planner offers a core element that bridges the gap between current and target states within the reactive loop. Burton is a sound, complete, reactive planner that generates a single control action of a valid plan in average case constant time, and compensates for anomalies at every step. Burton will not generate irreversible, potentially damaging sequences, except to effect repairs. We present model compilation, causal analysis, and online policy construction methods that are key to Burton's performance. C1 NASA, Ames Res Ctr, Computat Sci Div MS 269 2, Moffett Field, CA 94035 USA. RP Williams, BC (reprint author), NASA, Ames Res Ctr, Computat Sci Div MS 269 2, Moffett Field, CA 94035 USA. NR 0 TC 13 Z9 13 U1 0 U2 1 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA SN 1045-0823 BN 1-55860-480-4 J9 INT JOINT CONF ARTIF PY 1997 BP 1178 EP 1185 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BK59Y UT WOS:000072707200170 ER PT S AU Pell, B Gat, E Keesing, R Muscettola, N Smith, B AF Pell, B Gat, E Keesing, R Muscettola, N Smith, B BE Pollack, ME TI Robust periodic planning and execution for autonomous spacecraft SO IJCAI-97 - PROCEEDINGS OF THE FIFTEENTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE, VOLS 1 AND 2 SE INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE LA English DT Proceedings Paper CT 15th International Joint Conference on Artificial Intelligence CY AUG 23-29, 1997 CL NAGOYA, JAPAN SP Int Joint Conf Artificial Intelligence Inc, Japanese Soc Artificial Intelligence AB The New Millennium Remote Agent (NMRA) will be the first on-board AI system to control an actual spacecraft. The spacecraft domain raises a number of challenges far planning and execution, ranging from extended agency and long-term planning to dynamic recoveries, ies and robust concurrent execution, all in the presence of tight real-time deadlines, changing gods, scarce resource constraints, and a wide variety of possible failures. NMRA is one of the first systems to integrate closed-loop planning and execution of concurrent temporal plans. It is also the first autonomous system that will be able to achieve a sustained, multi-stage, multiyear mission without communication or guidance from earth. C1 NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. RP Pell, B (reprint author), NASA, Ames Res Ctr, Recom Technol, MS 269-2, Moffett Field, CA 94035 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN FRANCISCO PA 340 PINE STR, 6TH FLR, SAN FRANCISCO, CA 94104-3205 USA SN 1045-0823 BN 1-55860-480-4 J9 INT JOINT CONF ARTIF PY 1997 BP 1234 EP 1239 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BK59Y UT WOS:000072707200178 ER PT B AU Watson, AB Taylor, M Borthwick, R AF Watson, AB Taylor, M Borthwick, R BE Kim, YM TI DCTune perceptual optimization of compressed dental X-rays SO IMAGE DISPLAY - MEDICAL IMAGING 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Image Display - Medical Imaging 1997 CY FEB 23-25, 1997 CL NEWPORT BEACH, CA SP Soc Photo Opt Instrumentat Engineers, Amer Assoc Physicists Med, Amer Physiol Soc, US FDA, Ctr Devices & Radiol Hlth, Soc Imaging Sci & Technol, Natl Elect Manufacturers Assoc, Diagnost Imaging & Therapy Syst Div, Radiol Informat Syst Consortium, Radiol Soc N Amer, Soc Comp Applicat Radiol DE JPEG; compression; quantization; adaptive; image quality AB This is a brief report on research on the subject of DCTune optimization of JPEG compression of dental x-rays. DCTune is a technology for optimizing DCT quantization matrices to yield maximum perceptual quality for a given bit-rate, or minimum bit-rate for a given perceptual quality. In addition, the technology provides a means of setting the perceptual quality of compressed imagery in a systematic way. We optimized matrices for a total of 20 images at two resolutions (150 and 300 dpi) and four bit-rates (0.25, 0.5, 0.75, 1.0 bits/pixel), and examined structural regularities in the resulting matrices. We also conducted some brief psychophysical studies to validate the DCTune quality metric and to demonstrate the visual advantage of DCTune compression over standard JPEG. RP Watson, AB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2442-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3031 BP 358 EP 371 DI 10.1117/12.273914 PG 14 WC Optics; Radiology, Nuclear Medicine & Medical Imaging SC Optics; Radiology, Nuclear Medicine & Medical Imaging GA BH93H UT WOS:A1997BH93H00036 ER PT S AU Leung, K Nguyen, Q Cheng, T Tung, W AF Leung, K Nguyen, Q Cheng, T Tung, W BE Desachy, J Tajbakhsh, S TI Parallel computing implementation for ScanSAR mode data SO IMAGE PROCESSING, SIGNAL PROCESSING, AND SYNTHETIC APERTURE RADAR FOR REMOTE SENSING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Image Processing, Signal Processing, and Synthetic Aperture Radar for Remote Sensing CY SEP 22-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE parallel computing; concurrent processing; ScanSAR; burst mode; Alaska SAR Facility; Radarsat AB Synthetic aperture radar (SAR) data processing has matured over the past decade with development in processing approaches that include traditional time-domain methods, popular and efficient frequency-domain methods, and relatively new and more precise chirp-scaling methods. These approaches have been used in various processing applications to achieve various degrees of efficiency and accuracy. One common trait amongst ail SAR data processing algorithms, however, is their iterative and repetitive nature that make them amenable to parallel computing implementation. With SAR's contribution to remote sensing now well-established, the processing throughput demand has steadily increased with each new mission. Parallel computing implementation of SAR processing algorithms is therefore an important means of attaining high SAR data processing throughput to keep up with the ever-increasing science demand. This paper concerns parallel computing implementation of a mode of data called ScanSAR. ScanSAR has the unique advantage of yielding wide swath coverage in a single data collection pass. This mode of data collection has been demonstrated on SIR-C and is being used operationally for the first time on Radarsat. The burst nature of ScanSAR data is a natural candidate for parallel computing implementation. This paper gives a description of such an implementation experience at Alaska SAR Facility for Radarsat ScanSAR mode data. A practical concurrent processing technique is also described that allows further improvement in throughput at a slight increase in system cost. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Leung, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2649-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3217 BP 142 EP 151 DI 10.1117/12.295595 PG 10 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Computer Science; Engineering; Remote Sensing; Optics GA BK46C UT WOS:000072275200015 ER PT B AU Woodgate, B Kimble, R Bowers, C Kraemer, S Kaiser, ME Danks, A Grady, J Loiacono, J Hood, D Meyer, W VanHouten, C Argabright, V Bybee, R Timothy, JG Blouke, M Dorn, D Bottema, M Woodruff, R Michika, D Sullivan, J Hetlinger, J Stocker, R Brumfield, M Feinberg, L Delamere, A Rose, D Garner, H Lindler, D Gull, T Heap, S Joseph, C Green, R Jenkins, E Linsky, J Hutchings, J Moos, HW Boggess, A Maran, S Roesler, F Weistrop, D Sonneborn, G Bower, G Gardner, J AF Woodgate, B Kimble, R Bowers, C Kraemer, S Kaiser, ME Danks, A Grady, J Loiacono, J Hood, D Meyer, W VanHouten, C Argabright, V Bybee, R Timothy, JG Blouke, M Dorn, D Bottema, M Woodruff, R Michika, D Sullivan, J Hetlinger, J Stocker, R Brumfield, M Feinberg, L Delamere, A Rose, D Garner, H Lindler, D Gull, T Heap, S Joseph, C Green, R Jenkins, E Linsky, J Hutchings, J Moos, HW Boggess, A Maran, S Roesler, F Weistrop, D Sonneborn, G Bower, G Gardner, J BE Descour, MR Shen, SS TI First results from the Space Telescope Imaging Spectrograph. SO IMAGING SPECTROMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Spectrometry Conference CY JUL 28-30, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE Hubble; spectrograph; echelle; ultraviolet; optical; spectra; MAMA; black hole; galaxies; supernova AB The STIS instrument was installed into HST in February 1997 during the Servicing Mission 2. It has almost completed checkout and is beginning its science program, and is working well. Several scientific demonstration observations were taken, illustrating some of the range of scientific uses and modes of observation of STIS. RP Woodgate, B (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2540-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3118 BP 2 EP 12 DI 10.1117/12.283820 PG 11 WC Remote Sensing; Optics; Spectroscopy SC Remote Sensing; Optics; Spectroscopy GA BJ97Y UT WOS:A1997BJ97Y00001 ER PT B AU Wilson, DW Maker, PD Muller, RE AF Wilson, DW Maker, PD Muller, RE BE Descour, MR Shen, SS TI Reconstructions of computed-tomography imaging spectrometer image cubes using calculated system matrices SO IMAGING SPECTROMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Spectrometry Conference CY JUL 28-30, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE imaging spectrometry; tomography; image reconstruction; expectation-maximization algorithm AB The computed-tomography imaging spectrometer (CTIS) captures a scene's spatial and spectral information without any type of scanning. This capability enables a variety of applications that require spectral imaging of transient events. In this work, we demonstrate a flexible CTIS calibration technique that allows multiple scene resolutions to be reconstructed from a single detector frame. The technique combines measurements with simulations to determine the transfer matrix of the system. Reconstructions of an experimental scene are performed to demonstrate the flexibility of the approach. RP Wilson, DW (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2540-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3118 BP 184 EP 193 DI 10.1117/12.283827 PG 10 WC Remote Sensing; Optics; Spectroscopy SC Remote Sensing; Optics; Spectroscopy GA BJ97Y UT WOS:A1997BJ97Y00019 ER PT B AU Wang, Y Russell, SD Shimabukuro, RL AF Wang, Y Russell, SD Shimabukuro, RL BE Descour, MR Shen, SS TI Surface plasmon tunable filter and spectrometer-on-a-chip SO IMAGING SPECTROMETRY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Spectrometry Conference CY JUL 28-30, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE surface plasmons; tunable filter; electrooptics; thin film; spectrometer AB The surface plasmon tunable filter (SPTF) is a new technology invented at the Jet Propulsion Laboratory. When white light is incident on a metal/air/metal structure, under appropriate conditions, surface plasmon waves are excited at one metal/air material interface. Those photons in the surface plasmon resonance wavelength range will be converted into the energy of free electrons in the metal, then coupled into the other metal film which re-radiates light at the identical resonant wavelength. This surface plasmon resonance depends on the dielectric constant of the metal and the thickness of the air gap. When the thickness of the air gap changes, the surface plasmon resonance spectrum shifts from one wavelength to another, and the device functions as a tunable filter. The SPTF is a light weight, low power device, which can be integrated with a solid state image sensor to form a spectrometer-on-a-chip. Theoretical calculation has shown that this image spectrometer can also work in JR range up to at least 10 mu m. RP Wang, Y (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 1 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2540-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 3118 BP 288 EP 294 DI 10.1117/12.292689 PG 7 WC Remote Sensing; Optics; Spectroscopy SC Remote Sensing; Optics; Spectroscopy GA BJ97Y UT WOS:A1997BJ97Y00029 ER PT B AU Cutri, RM AF Cutri, RM BE Garzon, F Epchtein, N Omont, A Burton, B Persi, P TI The 2MASS point source processing pipeline: Design and prototype results SO IMPACT OF LARGE SCALE NEAR-IR SKY SURVEYS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Workshop on the Impact of Large Scale Near-IR Sky Surveys CY APR 22-26, 1996 CL PUERTO CRUZ, SPAIN SP Inst Astrofis Canarias, DENIS Grp RP Cutri, RM (reprint author), CALTECH,JET PROP LAB,CTR INFRARED PROC & ANAL,MS 100-22,PASADENA,CA 91125, USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4434-0 J9 ASTROPHYS SPACE SC L PY 1997 VL 210 BP 187 EP 195 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH46H UT WOS:A1997BH46H00037 ER PT B AU Jarrett, T Chester, T Schneider, S Huchra, J AF Jarrett, T Chester, T Schneider, S Huchra, J BE Garzon, F Epchtein, N Omont, A Burton, B Persi, P TI The effect of stellar contamination on different measures of galaxy photometry SO IMPACT OF LARGE SCALE NEAR-IR SKY SURVEYS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Workshop on the Impact of Large Scale Near-IR Sky Surveys CY APR 22-26, 1996 CL PUERTO CRUZ, SPAIN SP Inst Astrofis Canarias, DENIS Grp AB Stars superimposed on galaxies are a major problem for 2MASS and DENIS. If no effort is made to subtract stars, galaxy fluxes are biased high by >10% for 5-10% of galaxies at the pole, 10-20% of galaxies at b=20 degrees, and 50-80 degrees at b=5 degrees, where the lower number refers to a very local isophotal magnitude and the higher number refers to the total observed magnitude. The bias and number of galaxies affected is nearly independent of galaxy magnitude. We have therefore investigated a number of different star-subtraction techniques to derive the least biased measure, We used the observed galaxies from two prototype camera scans through tile Coma Cluster as a baseline, We then add artificial stars to these scans and determine the change in the galaxy photometry relative to the actual scans. For 2MASS, the measure with the smallest bias and scatter is one that computes a global background and subtracts nearly every detected neighboring source. The bias is less than 4% (3 sigma upper limit) even at densities corresponding to b=5 degrees, and the scatter due solely to stellar contamination is similar to 8%. Doing the same full subtraction at high Galactic latitudes causes only 2% of the galaxies to have a flux change of over 5%, and most of these changes are due to distinct stars on top of the galaxies or flux from a neighboring galaxy. RP Jarrett, T (reprint author), CALTECH,JET PROP LAB,IPAC,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4434-0 J9 ASTROPHYS SPACE SC L PY 1997 VL 210 BP 213 EP 220 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH46H UT WOS:A1997BH46H00041 ER PT B AU Moses, RW AF Moses, RW BE Sater, JM TI Vertical tail buffeting alleviation using piezoelectric actuators - Some results of the Actively Controlled Response Of Buffet-Affected Tails (ACROBAT) program SO INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES: SMART STRUCTURES AND MATERIALS 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Industrial and Commercial Applications of Smart Structures Technologies, at Smart Structures and Materials 1997 Meeting CY MAR 04-06, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Mech engineers, USAF Wright Lab, Def Adv Res Projects Agcy, Intelligent Mat Forum, Japan, Amer Inst Chem Engineers, Amer Phys Soc, Div Mat Phys, Ceram Soc Japan, USA Res Lab DE piezoelectric; buffeting alleviation; active controls AB A 1/6-scale F-18 wind-tunnel model was tested in the Transonic Dynamics Tunnel at the NASA Langley Research Center as part of the Actively Controlled Response Of Buffet Affected Tails (ACROBAT) program to assess the use of active controls in reducing vertical tail buffeting. The starboard vertical tail was equipped with an active rudder and the port vertical tail was equipped with piezoelectric actuators. The tunnel conditions were atmospheric air at a dynamic pressure of 14 psf. By using single-input-single-output control laws at gains well below the physical limits of the actuators, the power spectral density of the root strains at the frequency of the first bending mode of the vertical tail was reduced by as much as 60 percent up to angles of attack of 37 degrees. Root mean square (RMS) values of root strain were reduced by as much as 19 percent. Buffeting alleviation results when using the rudder are presented for comparison. Stability margins indicate that a constant gain setting in the control law may be used throughout the range of angle of attack tested. RP Moses, RW (reprint author), NASA,LANGLEY RES CTR,AEROELAST BRANCH,HAMPTON,VA 23665, USA. NR 0 TC 13 Z9 13 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2457-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3044 BP 87 EP 98 DI 10.1117/12.274700 PG 12 WC Engineering, Aerospace; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BH98C UT WOS:A1997BH98C00009 ER PT B AU Wise, SA Hardy, RC Dausch, DE AF Wise, SA Hardy, RC Dausch, DE BE Sater, JM TI Design and development of an optical path difference scan mechanism for Fourier transform spectrometers using high displacement RAINBOW actuators SO INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES: SMART STRUCTURES AND MATERIALS 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Industrial and Commercial Applications of Smart Structures Technologies, at Smart Structures and Materials 1997 Meeting CY MAR 04-06, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Mech engineers, USAF Wright Lab, Def Adv Res Projects Agcy, Intelligent Mat Forum, Japan, Amer Inst Chem Engineers, Amer Phys Soc, Div Mat Phys, Ceram Soc Japan, USA Res Lab DE optical translation; Fourier transform spectrometers; high displacement actuators; RAINBOWs; actuator slacks AB A new piezoelectric drive mechanism has bean developed for optical translation in space-based spectrometer systems, The mechanism utilizes a stack of RAINBOW high displacement piezoelectric actuators to move optical components weighing less than 250 grams through a one centimeter travel. The mechanism uses the direct motion of the piezoelectric devices, stacked such that the displacement of the individual RAINBOW actuators is additive. A prototype device has been built which utilizes 21 RAINBOWs to accomplish the necessary travel. The mechanism weighs approximately 0.6 kilograms and uses less than 2 Watts of power ar a scanning frequency of 0.5 Hertz, significantly less power than that required by state-of-the-art motor systems. RP Wise, SA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2457-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3044 BP 342 EP 349 DI 10.1117/12.274677 PG 8 WC Engineering, Aerospace; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BH98C UT WOS:A1997BH98C00033 ER PT B AU Hooker, MW AF Hooker, MW BE Sater, JM TI Properties and performance of RAINBOW piezoelectric actuator stacks SO INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES: SMART STRUCTURES AND MATERIALS 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Industrial and Commercial Applications of Smart Structures Technologies, at Smart Structures and Materials 1997 Meeting CY MAR 04-06, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Mech engineers, USAF Wright Lab, Def Adv Res Projects Agcy, Intelligent Mat Forum, Japan, Amer Inst Chem Engineers, Amer Phys Soc, Div Mat Phys, Ceram Soc Japan, USA Res Lab DE RAINBOWs; actuators; stacks; high-displacement AB Stacks of RAINBOW high-displacement actuators are currently under consideration for use in scanning mechanisms capable of providing controlled travels on the order of 1 cm. In this work actuator stacks were produced by stacking PZT-5A and PZT-5H RAINBOWs in a clamshell configuration The displacement properties of the RAINBOW stacks were then evaluated as a function of applied electric field, static load number of actuators in the stack and diameter of the actuators. The displacement properties of the stacks were found to increase nearly proportionately to the number of actuators in the stack, with the PZT-5A RAINBOW stacks generating one and a half to two times the displacement of the PZT-5H stacks at +/-8 and +/-16 kV/cm. RP Hooker, MW (reprint author), NASA,LANGLEY RES CTR,LOCKHEED MARTIN ENGN & SCI,MAIL STOP 188B,HAMPTON,VA 23681, USA. NR 0 TC 13 Z9 13 U1 1 U2 3 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2457-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3044 BP 413 EP 420 DI 10.1117/12.274686 PG 8 WC Engineering, Aerospace; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BH98C UT WOS:A1997BH98C00042 ER PT J AU Weisbin, CR Lavery, D Rodriguez, G AF Weisbin, CR Lavery, D Rodriguez, G TI Robots in space into the 21st century SO INDUSTRIAL ROBOT LA English DT Article DE automation; robotics; robots ID CONFIGURATION CONTROL; MANIPULATORS AB Describes the technological developments which are establishing the foundation for an exciting era of in situ exploration missions to planets, comets and asteroids with advanced robotic systems. Also outlines important concurrent terrestrial applications and spin offs of the space robotics technology. These include high-precision robotic manipulators for microsurgical operations and dexterous arm control systems. C1 NASA,TELEROBOT RES & MARS TECHNOL PROGRAM,NASA HEADQUARTERS,WASHINGTON,DC 20024. RP Weisbin, CR (reprint author), CALTECH,JET PROP LAB,ROBOT & MARS EXPLORAT TECHNOL,4800 OAK GROVE DR,MAIL STOP 180-603,PASADENA,CA 91109, USA. NR 25 TC 0 Z9 1 U1 0 U2 0 PU MCB UNIV PRESS LTD PI BRADFORD PA 60/62 TOLLER LANE, BRADFORD, W YORKSHIRE, ENGLAND BD8 9BY SN 0143-991X J9 IND ROBOT JI Ind. Robot PY 1997 VL 24 IS 2 BP 169 EP & DI 10.1108/01439919710165734 PG 14 WC Engineering, Industrial; Robotics SC Engineering; Robotics GA XC587 UT WOS:A1997XC58700013 PM 11540587 ER PT B AU Bejczy, AK AF Bejczy, AK BE Rudas, IJ TI Task-level servocontrol in robotics SO INES'97 : 1997 IEEE INTERNATIONAL CONFERENCE ON INTELLIGENT ENGINEERING SYSTEMS, PROCEEDINGS LA English DT Proceedings Paper CT 1997 IEEE International Conference on Intelligent Engineering Systems (INES 97) CY SEP 15-17, 1997 CL BUDAPEST, HUNGARY SP IEEE Ind Electr Soc, IEEE Hungary Sect, Banki Donat Polytech, Hungary, Natl Comm Technol Dev, Hungary, IEEE Robot & Automat Soc DE robot arm control, model errors, joint space; task space relations AB Application of computers permit the design and implementation of several different types of servocontrol schemes for the control of robot arms. This paper focuses on the description of task-space error feedback techniques which can provide excellent performance for tracking position and force trajectories in both manual and automatic modes of control. Model assumptions and computational requirements implied in these techniques are outlined and the outstanding performance capabilities of the techniques are illustrated by numerous experimental results. RP Bejczy, AK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3627-5 PY 1997 BP 39 EP 47 PG 9 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Manufacturing; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BJ96E UT WOS:A1997BJ96E00004 ER PT S AU Manthripragada, S Hu, K Peters, F Burgess, A Babu, S Shi, J Krebs, D Mott, DB Shu, P AF Manthripragada, S Hu, K Peters, F Burgess, A Babu, S Shi, J Krebs, D Mott, DB Shu, P BE Manaasreh, MO Myers, TH Julien, FH TI Off-area bonding of HgCdTe photoconductive infrared detectors using tri-layer photolithography and wet/dry etching techniques SO INFRARED APPLICATIONS OF SEMICONDUCTORS - MATERIALS, PROCESSING AND DEVICES SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Infrared Applications of Semiconductors - Materials, Processing and Devices, at 1996 MRS Fall Meeting / 1996 International Conference on Electronic Materials CY DEC 02-06, 1996 CL BOSTON, MA SP Mat Res Soc AB On-area wire bonding of HgCdTe photoconductive (PC) infrared detectors usually causes material damage underneath the bonding pads. Such damage may propagate into the active area, potentially degrading performance and posing long-term reliability problems. Some off-area bonding fabrication techniques can also induce some degree of semiconductor material damage. In this paper, we report a relatively straightforward off-area bonding scheme that solves these problems. The process uses multiple photolithography and chemical etching steps to create a continuous slope or staircase in the HgCdTe leading down to the epoxy surface. The staircase ensures smooth step coverage for the subsequent metalization. Tri-layer photolithography (resist/metal/resist) and reactive ion etching (RIE) is then used to remove the epoxy in the bonding pad area. Since all areas other than the pad region are protected by the metal film, no RIE radiation damage is induced to the active area. The contact metalization is achieved by using standard liftoff techniques. Our so called staircase off-area bonding fabrication technique can be used to fabricate highly reliable, high density, small-size, detector arrays. RP Manthripragada, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 718,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-354-1 J9 MATER RES SOC SYMP P PY 1997 VL 450 BP 301 EP 306 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Materials Science, Multidisciplinary; Optics SC Engineering; Instruments & Instrumentation; Materials Science; Optics GA BH52B UT WOS:A1997BH52B00041 ER PT B AU Wooden, DH AF Wooden, DH BE Eiroa, C Alberdi, A Thronson, H DeGraauw, T Schalinski, CJ TI Stellar death: Ejecta and circumstellar matter SO INFRARED SPACE INTERFEROMETRY: ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT UAM/LAEFF/IAA Workshop on Infrared Space Interferometry - Astrophysics and the Study of Earth-Like Planets CY MAR 11-14, 1996 CL TOLEDO, SPAIN SP UAM, LAEFF, IAA DE dust condensation; C-rich and O-rich AGB stars; novae; supernovae AB IR 15 milli-arcsecond interferometry in the 5-15 mu m wavelength region of the circumstellar environments of AGE stars probes the dust condensation zones close to the stellar photospheres. Interferometric measurements which spatially resolve Galactic novae will provide distance determinations, can reveal dense knots in the structure of the ejected shells, will probe nonspherical accretion onto the compact white dwarfs, and in many novae will witness dust grain growth despite grain destruction by photodesorption and sputtering. Interferometric imaging of nearby supernovae (d less than or equal to 50 kpc) will show the explosion structure frozen-in to the homologously expanding ejecta, the interaction of the ejecta with the surrounding medium, and possibly dust formation in an iron-and nickel rich ejecta. Interferometric reconnaissance of the chemically anomalous clumpy outflows and ejecta of AGE stars, novae, and supernovae will scrutinize the theories for the microscopic processes of dust nucleation, grain cluster aggregation, grain sputtering, and photodesorption of grains, i.e., critical processes dictating the enrichment of the ISM. RP Wooden, DH (reprint author), NASA,AMES RES CTR,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4598-3 J9 ASTROPHYS SPACE SC L PY 1997 VL 215 BP 133 EP 145 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ51J UT WOS:A1997BJ51J00019 ER PT B AU Coulter, DR Macenka, SA AF Coulter, DR Macenka, SA BE Eiroa, C Alberdi, A Thronson, H DeGraauw, T Schalinski, CJ TI Recent advances in cryogenic optics technology for space infrared telescope and interferometer systems SO INFRARED SPACE INTERFEROMETRY: ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT UAM/LAEFF/IAA Workshop on Infrared Space Interferometry - Astrophysics and the Study of Earth-Like Planets CY MAR 11-14, 1996 CL TOLEDO, SPAIN SP UAM, LAEFF, IAA DE cryogenic optics technology; space infrared interferometry AB In this paper we will describe recent advances in the development of optical systems for future space infrared telescope and interferometer applications which will operate at very low or cryogenic temperatures (T less than or equal to 77K) with emphasis on beryllium and silicon carbide optics. New material formulations and advanced processing and manufacturing techniques are enabling the development of large, very low mass, high performance cryogenic optics. The design, manufacturing and cryogenic testing of several recently developed mirrors and optical assemblies will be discussed. RP Coulter, DR (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4598-3 J9 ASTROPHYS SPACE SC L PY 1997 VL 215 BP 173 EP 185 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ51J UT WOS:A1997BJ51J00024 ER PT B AU Mather, J AF Mather, J BE Eiroa, C Alberdi, A Thronson, H DeGraauw, T Schalinski, CJ TI The next generation space telescope (NGST) SO INFRARED SPACE INTERFEROMETRY: ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT UAM/LAEFF/IAA Workshop on Infrared Space Interferometry - Astrophysics and the Study of Earth-Like Planets CY MAR 11-14, 1996 CL TOLEDO, SPAIN SP UAM, LAEFF, IAA DE infrared; space telescope AB The Next Generation Space Telescope (NGST) is under study by NASA as a successor to the Hubble Space Telescope (HST), and the infrared missions SIRTF (Space Infrared Telescope Facility), SOFIA (Stratospheric Observatory for Infrared Astronomy), and ISO (Infrared Space Observatory). It would have an aperture > 4 m, optimized for 1-5 mu m, with a goal of 8 m and 0.5 -20 mu m. It would be radiatively cooled and would be launched on an Atlas IIAS to the Lagrange Point L2 around 2006. At wavelengths longer than a few mu m, it offers a speed advantage of the order of 10(6) over a large ground based telescope. RP Mather, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INFRARED ASTROPHYS BRANCH,CODE 685,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4598-3 J9 ASTROPHYS SPACE SC L PY 1997 VL 215 BP 227 EP 232 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ51J UT WOS:A1997BJ51J00031 ER PT B AU Shao, M Unwin, S Boden, A VanBuren, D Kulkarni, S AF Shao, M Unwin, S Boden, A VanBuren, D Kulkarni, S BE Eiroa, C Alberdi, A Thronson, H DeGraauw, T Schalinski, CJ TI Space interferometry mission SO INFRARED SPACE INTERFEROMETRY: ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT UAM/LAEFF/IAA Workshop on Infrared Space Interferometry - Astrophysics and the Study of Earth-Like Planets CY MAR 11-14, 1996 CL TOLEDO, SPAIN SP UAM, LAEFF, IAA DE space; interferometry; astrometry; imaging AB The Space Interferometry Mission (SIM) will be a 10-m optical interferometer in Earth orbit. SIM will enable a wide variety of science programs in Galactic and extra-galactic astronomy, including the calibration of cosmic distance indicators, and will address questions related to the origins and prevalence of planetary systems. SIM is designed primarily as an astrometric mission, providing high-throughput wide-angle astrometry, with an expected noise floor of about 4 mu as for bright targets, and about 1 mu as over small angles. Accurate parallaxes and proper motions will be available for a large number of stars of various types, providing data for fundamental programs in the stellar dynamics of star clusters and our Galaxy as a whole. SIM will have seven light-collecting siderostats (effective diameters 0.3m) spaced along the main boom, to allow synthesis imaging with a resolution of 10 mas, by rotating the spacecraft about the line of sight. It is NASA's first space science interferometer, and in addition to enabling a strong astronomical science program, it is designed to demonstrate several key technologies needed for future missions in NASA's Origins Program, such as the Next Generation Space Telescope (NGST) and Terrestrial Planet Finder (TPF). Interferometric nulling will be used by TPF to provide coronagraphic-type extinction of a bright star, allowing detection of faint companions. SIM will implement an achromatic null to a level of 10(-4) and will study dust disks around main-sequence stars, and image the disks around young stellar objects. RP Shao, M (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4598-3 J9 ASTROPHYS SPACE SC L PY 1997 VL 215 BP 267 EP 278 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ51J UT WOS:A1997BJ51J00036 ER PT B AU Martineau, RJ Shi, J Hu, K Manthripragada, S Peters, FA Burgess, AS Godfrey, J Krebs, DJ AF Martineau, RJ Shi, J Hu, K Manthripragada, S Peters, FA Burgess, AS Godfrey, J Krebs, DJ BE Strojnik, M Andresen, BF TI PC detector passivation for high performance SO INFRARED SPACEBORNE REMOTE SENSING V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 5th Conference on Infrared Spaceborne Remote Sensing, at SPIEs Annual Meeting CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE passivation; infrared; HgCdTe; detector AB Probably the most important factor in producing HgCdTe detectors of high performance is surface passivation. A good passivant for PC HgCdTe detectors accumulates the surface thereby reflecting minority carriers from surface imperfections and increasing minority carrier lifetime. A variety of passivants are known and used to various degrees, including sulfides, fluorides, oxides, and others. One of the problems with known passivants is that they tend to accumulate the surface too strongly, thus producing non-optimal results. We have developed a new passivation process which passivates the surface without strong accumulation. This results in detector resistance that is about 50% higher than that achieved with traditional KOH passivation, responsivities that are from 100 to 200% higher, and detectivities that are from 50 to 100% higher for long wavelength devices. Materials and processing details used to achieve these results, as well as experimental data will be presented. RP Martineau, RJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 718,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2544-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3122 BP 392 EP 398 DI 10.1117/12.279000 PG 7 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ90W UT WOS:A1997BJ90W00036 ER PT B AU Gunapala, SD Krabach, TN Bandara, SV Liu, JK Sundaram, M AF Gunapala, SD Krabach, TN Bandara, SV Liu, JK Sundaram, M BE Andresen, BF Strojnik, M TI Applications of long-wavelength 256x256 quantum well infrared photodetector (QWIP) hand-held camera SO INFRARED TECHNOLOGY AND APPLICATIONS XXIII, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXIII Conference CY APR 20-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers AB A 9 mu m cutoff 256 x 256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 26 mK has been achieved. In this paper, we discuss the performance of this portable long-wavelength infrared camera in quantum efficiency, NE Delta T, minimum resolvable temperature difference (MRTD), uniformity, etc. and its applications in science, medicine and defense. RP Gunapala, SD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 2 U2 3 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2476-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 3061 BP 292 EP 299 DI 10.1117/12.280347 PG 8 WC Optics SC Optics GA BJ64N UT WOS:A1997BJ64N00032 ER PT B AU Gunapala, SD Bandara, SV Liu, JK Hong, W Sundaram, M Carralejo, R Shott, CA Maker, PD Miller, RE AF Gunapala, SD Bandara, SV Liu, JK Hong, W Sundaram, M Carralejo, R Shott, CA Maker, PD Miller, RE BE Andresen, BF Strojnik, M TI Long-wavelength 640x484 GaAs/AlxGa1-xAs quantum well infrared photodetector focal plane array camera SO INFRARED TECHNOLOGY AND APPLICATIONS XXIII, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXIII Conference CY APR 20-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE intersubband transitions; infrared (IR); long-wavelength infrared (LWIR); gallium arsenide (GaAs); quantum well infrared photodetector (QWIP); focal plane arrays; noise equivalent temperature difference (NE Delta T); infrared imaging cameras AB A 9 mu m cutoff 640x484 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 43 mi; has been achieved. in this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NE Delta T, uniformity, and operability. RP Gunapala, SD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 18 Z9 18 U1 1 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2476-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 3061 BP 722 EP 727 DI 10.1117/12.280393 PG 6 WC Optics SC Optics GA BJ64N UT WOS:A1997BJ64N00074 ER PT B AU Bandara, SV Gunapala, SD Liu, JK Hong, W Park, JS AF Bandara, SV Gunapala, SD Liu, JK Hong, W Park, JS BE Andresen, BF Strojnik, M TI Two dimensional periodic grating light coupling in quantum well infrared photodetectors SO INFRARED TECHNOLOGY AND APPLICATIONS XXIII, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Infrared Technology and Applications XXIII Conference CY APR 20-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE Quantum Wells; intersubband; infrared; detectors; grating AB Quantum Well Infrared Photodetectors do not respond to normal incident light due to the quantum mechanical selection rules associated with intersubband transitions, Thus alternate light coupling systems, such as gratings are required in order deflect the incoming light away from the normal. The resolution of the photolithography and accuracy of the etching become key issues in producing mailer grating feature sizes especially in shorter wavelengths. An enhancement factor of three due to 2D periodic grating fabricated on a QWIP structure was observed. Variation of the enhancement factor with groove depth and feature size of the grating can be theoretically explained. RP Bandara, SV (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2476-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 3061 BP 758 EP 763 DI 10.1117/12.280394 PG 6 WC Optics SC Optics GA BJ64N UT WOS:A1997BJ64N00078 ER PT B AU Barengoltz, JB AF Barengoltz, JB GP INST ENVIRONM SCI TI Microbiological cleanliness of the Mars Pathfinder spacecraft SO INSTITUTE OF ENVIRONMENTAL SCIENCES, 1997 PROCEEDINGS - CONTAMINATION CONTROL LA English DT Proceedings Paper CT 43rd Annual Technical Meeting on Integrated Product Development CY MAY 04-08, 1997 CL LOS ANGELES, CA SP Inst Environm Sci DE contamination; Mars; microbiology; planetary protection; spacecraft AB The recently launched Mars Pathfinder spacecraft, involving a lander and a rover scheduled to land on Mars in July 1997, was required to comply with the National Aeronautics and Space Administration planetary protection regulations for such space missions. The microbial cleanliness requirements drove a major, successful effort to assemble a clean spacecraft and to verify and maintain its cleanliness. Planetary protection for Mars missions is introduced, and the approach taken by the Mars Pathfinder Project is discussed. Specific topics include ethyl alcohol wiping, dry heat microbial reduction, microbiological assays, and the Kennedy Space Center's SAEF-2 clean room. Quantitative results for the number of aerobic spores found on the spacecraft are presented and compared to the Viking 1975 values. RP Barengoltz, JB (reprint author), CALTECH,JET PROP LAB,MECH SYST ENGN & RES DIV,MAT TESTING & CONTAMINAT CONTROL GRP,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 BN 1-877862-54-1 PY 1997 BP 242 EP 248 PG 7 WC Engineering, Environmental; Engineering, Chemical; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA BJ08K UT WOS:A1997BJ08K00034 ER PT B AU Aveni, GJ AF Aveni, GJ GP INST ENVIRONM SCI TI Contamination control for the Cassini imaging science subsystem SO INSTITUTE OF ENVIRONMENTAL SCIENCES, 1997 PROCEEDINGS - CONTAMINATION CONTROL LA English DT Proceedings Paper CT 43rd Annual Technical Meeting on Integrated Product Development CY MAY 04-08, 1997 CL LOS ANGELES, CA SP Inst Environm Sci DE Cassini; ISS; contamination control; molecular; particulate; susceptibility; signal throughput degradation; UV sensitive; transport factors; flux; fluence; control plan; MCIF; TQCMs; NVR; PCL AB The contamination control activity performed for the Cassini Imaging Science Subsystem (ISS) consisted of an overall system analysis for susceptibility to molecular and particulate contamination at the sensor's most sensitive wavelengths. This analysis considered the system functional requirements, the expected sources of contaminants, the expected effects of those contaminants, and the transport of those contaminants to the sensors. The derived requirements and a plan to meet them during assembly, test, and storage of the instrument were documented in the Contamination Handling Requirements (procedure). The final phase of the contamination control activity was to monitor the hardware (record data and implement cleaning procedures) during assembly and thermal vacuum testing prior to delivery to Assembly, Test and Launch Operations (ATLO). RP Aveni, GJ (reprint author), CALTECH,JET PROP LAB,CONTAMINAT CONTROL TEAM,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 BN 1-877862-54-1 PY 1997 BP 249 EP 254 PG 6 WC Engineering, Environmental; Engineering, Chemical; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA BJ08K UT WOS:A1997BJ08K00035 ER PT B AU Barnes, C Johnston, A Lee, C Swift, G Rax, B AF Barnes, C Johnston, A Lee, C Swift, G Rax, B GP INST ENVIRONM SCI TI Radiation issues associated with the insertion of commercial technologies in space systems SO INSTITUTE OF ENVIRONMENTAL SCIENCES, 1997 PROCEEDINGS - DESIGN, TEST, AND EVALUATION - PRODUCT RELIABILITY LA English DT Proceedings Paper CT 43rd Annual Technical Meeting on Integrated Product Development CY MAY 04-08, 1997 CL LOS ANGELES, CA SP Inst Environm Sci AB In this payer we discuss radiation effects issues that have become important for NASA programs in the last few years. Particularly critical is the increasing usage of commercial off-the-shelf (COTS) devices and circuits in interplanetary missions that experience significant exposure to radiation. Demands for increased performance levels in spacecraft systems will drive the insertion of the latest electronic and photonic devices. Advances in electronics to achieve high performance will result in scaling (miniaturization) of devices, which, in turn, will lead to increased radiation vulnerability in many cases. These issues are discussed within the context of recent technical examples of challenging radiation effects problems. RP Barnes, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST ENVIRONMENTAL SCIENCES PI MT PROSPECT PA 940 E NORTHWEST HIGHWAY, MT PROSPECT, IL 60056 BN 1-877862-55-X PY 1997 BP 196 EP 210 PG 15 WC Engineering, Multidisciplinary; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA BJ09L UT WOS:A1997BJ09L00031 ER PT B AU McKay, DS Gibson, EK ThomasKeprta, K Romanek, CS AF McKay, DS Gibson, EK ThomasKeprta, K Romanek, CS BE Hoover, RB TI Evidence for possible past life in a Martian meteorite: A current assessment SO INSTRUMENTS, METHODS, AND MISSIONS FOR THE INVESTIGATION OF EXTRATERRESTRIAL MICROORGANISMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms CY JUL 29-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers AB In the initial report by McKay et al.(1) on ALH84001 several lines of evidence were given to suggest the presence of biogenic activity on Mars: (i) the presence of the carbonate globules within fractures and pores of a 4.5 Gy old igneous rock after the primary crystallization event; (ii) formation age: of the carbonates is younger than the age of the host Igneous rock but older than the carbonate's age; (iii) SEM and TEM images of carbonate globules and assorted features resemble terrestrial biogenic structures and fossilized nanobacteria; (iv) the occurrence of magnetite and iron sulfide particles could have resulted from oxidation and reduction reactions known to be important in terrestrial microbial systems; and. (v) presence of PAHs associated carbonate globules indicating potential indigenous organic molecules. As noted in McKay et al.(1), none of these observations is in itself conclusive proof for the existence of past life on Mars. Although there are alternative explanations for each of these phenomena taken individually, when they are considered collectively, particularly in view of their close spatial association, it was concluded that they may represent the first direct; evidence for primitive life on early Mars. Since the initial report, additional supporting evidence(2-8) and contradictory evidence(9-14), including alternative inorganic explanations have been presented. The time and temperatures of carbonate formation in ALH84001 continues to be hotly debated. Knoft et al.(15) suggests the carbonates were formed at 3.6 Gy, whereas Wadhwa and Lugmair(16) noted the formation may be as late as 1.3 Gy. Turner et al.(17) argue that the 3.6 Gy date is not; well defined and additional studies are needed to define the carbonate formation date. RP McKay, DS (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,ES & SSED,HOUSTON,TX 77058, USA. NR 0 TC 1 Z9 1 U1 1 U2 3 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2533-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3111 BP 2 EP 6 DI 10.1117/12.278774 PG 5 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BJ31K UT WOS:A1997BJ31K00001 ER PT B AU Hoover, RB AF Hoover, RB BE Hoover, RB TI Meteorites, microfossils, and exobiology SO INSTRUMENTS, METHODS, AND MISSIONS FOR THE INVESTIGATION OF EXTRATERRESTRIAL MICROORGANISMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms CY JUL 29-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE SNC meteorites; Murchison; carbonaceous chondrites; exobiology; extremophiles; microfossils AB The discovery of evidence for biogenic activity and possible microfossils in a Martian meteorite may have initiated a paradigm shift regarding the existence of extraterrestrial microbial life. Terrestrial extremophiles that live in deep granite and hydrothermal vents and nanofossils in volcanic tuffs have altered the premise that microbial life and microfossils are inconsistent with volcanic activity and igneous rocks. Evidence for biogenic activity and microfossils in meteorites can no longer be dismissed solely because the meteoritic rock matrix is not sedimentary. Meteorite impact-ejection and comets provide mechanisms for planetary cross-contamination of biogenic chemicals, microfossils, and living microorganisms. Hence, previously dismissed evidence for complex indigenous biochemicals and possible microfossils in carbonaceous chondrites must be re-examined. Many similar, unidentifiable, biological-like microstructures have been found in different carbonaceous chondrites and the prevailing terrestrial contaminant model is considered suspect. This paper reports the discovery of microfossils indigenous to the Murchison meteorite. These forms were found in-situ in freshly broken, interior surfaces of the meteorite. Environmental Scanning Electron Microscope (ESEM) and optical microscopy images indicate that a population of different biological-like forms are represented. Energy Dispersive Spectroscopy reveals these forms have high carbon content overlaying an elemental distribution similar to the matrix. Efforts at identification with terrestrial microfossils and microorganisms were negative. Some forms strongly resemble bodies previously isolated in the Orgueil meteorite and considered microfossils by prior researchers. The Murchison forms are interpreted to represent an indigenous population of the preserved and altered carbonized remains (microfossils) of microorganisms that lived in the parent body of this meteorite at diverse times during the past 4.5 billion years (Gy). RP Hoover, RB (reprint author), GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES82,HUNTSVILLE,AL 35812, USA. NR 0 TC 31 Z9 32 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2533-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3111 BP 115 EP 136 DI 10.1117/12.278766 PG 22 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BJ31K UT WOS:A1997BJ31K00013 ER PT B AU Farmer, JD AF Farmer, JD BE Hoover, RB TI Implementing a strategy for Mars exopaleontology SO INSTRUMENTS, METHODS, AND MISSIONS FOR THE INVESTIGATION OF EXTRATERRESTRIAL MICROORGANISMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms CY JUL 29-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE Mars; exploration exopaleontology; geology; mineralogy; robotics; rovers; spectroscopy; sedimentary; sample AB A critical step in implementing a strategy to explore for evidence of past or present Martian life and/or prebiotic chemistry is to locate accessible surface outcrops of aqueously-formed sedimentary deposits, especially fine-grained, clay-rich detrital sediments, water-lain volcanic ash deposits, and chemical precipitates which provide especially favorable environments for microbial fossilization. We are presently limited in our site selection efforts by a lack of high spatial resolution remote sensing data at wavelengths that can provide information about surface mineralogy. Globally-distributed compositional data will be obtained at an average spatial resolution of similar to 3 km/pixel by the Thermal Emission Spectrometer (TES) instrument launched on the Global Surveyor orbiter in 1996. This will provide a basis for initial targeting of sites for a landed rover missions in 2001 and '03 which will cache samples for potential Earth return in '05. During '05, a sample return vehicle will be sent to one of the previous landed mission sites based on what is learned from those missions during in situ rover investigations. To optimize planning for rover missions to explore for evidence of past life, we need to attain outcrop-scale spatial resolution in the range similar to 100 to 300 m/pixel. This will be required to precisely locate sedimentary deposits of the right mineralogy (i.e. rock types most favorable for preserving a fossil record of past life) at landing sites and be able to reach them with rovers during nominal mission times. The earliest opportunity to obtain high spatial resolution orbital mapping of mineralogy is the 2001 opportunity. This data is needed as early as possible in the (Oa mission to influence the landing site selection for the '03 rover mission. RP Farmer, JD (reprint author), NASA,AMES RES CTR,MS 239-4,MOFFETT FIELD,CA 94035, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2533-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3111 BP 200 EP 212 DI 10.1117/12.278773 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BJ31K UT WOS:A1997BJ31K00020 ER PT B AU Horvath, J Carsey, F Cutts, J Jones, J Johnson, E Landry, B Lane, L Lynch, G Jezek, K ChelaFlores, J Jeng, TW Bradley, A AF Horvath, J Carsey, F Cutts, J Jones, J Johnson, E Landry, B Lane, L Lynch, G Jezek, K ChelaFlores, J Jeng, TW Bradley, A BE Hoover, RB TI Searching for ice and ocean biogenic activity on Europa and Earth SO INSTRUMENTS, METHODS, AND MISSIONS FOR THE INVESTIGATION OF EXTRATERRESTRIAL MICROORGANISMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Instruments, Methods, and Missions for the Investigation of Extraterrestrial Microorganisms CY JUL 29-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE Europa; exobiology; instrumentation; submersibles; ice probes AB One of the more likely places in the solar system for the existence of extraterrestrial life forms is the Jovian moon Europa. It has been postulated that a volcanically-heated ocean is likely to exist underneath Europa's icy surface. If a detailed remote-sensing reconnaissance of Europa determines that an ocean does exist under the ice, then in-situ measurements will be needed to directly explore the Europan ocean and the ice that lies above it. In order to make quantitative measurements of the Europan environment, a lander spacecraft capable of penetrating the surface ice layer by melting through it is proposed, This vehicle, dubbed a ''Cryobot'', will be designed to carry a small deployable submersible (a ''Hydrobot'') equipped with a complement of instruments. The design of an instrument package to search for li-fe across the wide range of thermal and pressure environments expected on Europa, the issues in sample handling, and long-term reliability for a potential multi-year transit through the ice all present difficult design issues. Opportunities for performing investigations of deep, submerged Antarctic lakes on Earth are described which would test the Cryobot/Hydrobot system while collecting intrinsically valuable terrestrial science data. RP Horvath, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 8 Z9 8 U1 0 U2 4 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2533-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3111 BP 490 EP 500 DI 10.1117/12.278805 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Instruments & Instrumentation; Microbiology; Optics GA BJ31K UT WOS:A1997BJ31K00048 ER PT J AU Miranda, FA Romanofsky, RR VanKeuls, FW Mueller, CH Treece, RE Rivkin, TV AF Miranda, FA Romanofsky, RR VanKeuls, FW Mueller, CH Treece, RE Rivkin, TV TI Thin film multilayer conductor ferroelectric tunable microwave components for communication applications SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 9th International Symposium on Integrated Ferroelectrics CY MAR 02-05, 1997 CL SANTA FE, NM SP USN, Naval Postgraduate Sch, Univ Colorado, Gordon & Breach Sci Publ, Integrated Ferroelectrics, Sandia Natl Lab, Symetrix Corp DE (HTS,metal)/ferroelectric structures; tunable microwave components; dielectric constant; loss tangent; parallel plate and interdigital capacitors; phase shifters; ring resonators ID PHASE SHIFTERS AB A study of Au/SrTiO3/YBa2Cu3O7-delta/LaAlO3 and (Au,YBa2Cu3O7-delta)/BaxSr1-xTiO3/LaAlO3 (x = 0, 0.50, and 0.40) multilayered structures is presented. At 1.0 MHz, the largest tuning of Au/SrTiO3/YBa(2)Cu(3)0(7-delta) parallel plate capacitors corresponded to single-phased, epitaxial 300-500 nm thick SrTiO3 thin films deposited at 800 degrees C. For SrTiO3/LaAlO3 structures having SrTiO3 films of similar quality, we observed that at 1.0 MHz and 77 K, interdigital capacitors exhibit higher tunabilities and lower losses than parallel plate configurations, but required higher dc voltage. For a 300 nm thick SrTiO3 film, a 25 Omega YBa2Cu3O7-delta/SrTiO3/LaAlO3 phase shifter exhibited a phase shift similar to 2.6 times larger than its Au/SrTiO3/LaAlO3 counterpart. At 19 GHz and 32V, a 360 degrees phase shift could in principle be achieved with coupled microstripline sections only 7.0 mm long. At 14 GHz, 77 K and 260 V, for 1.0 mu m and 300 nm thick SrTiO3 films, 25 Omega 360 degrees Au/SrTiO3/LaAlO3 phase shifters would be nominally 4.0 mm and 12 mm long, respectively. For a 2 lambda YBa2Cu3 O7-deltaSrTiO3/LaAlO3 ring resonator a tuning rate of 0.7 MHz/Volt was achieved at 10 GHz and 77 K. The relevance of these structures for phased array antennas and as tunable elements in discriminator-stabilized oscillators is discussed. C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. SCT, GOLDEN, CO 80401 USA. RP NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 13 TC 39 Z9 39 U1 1 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 1058-4587 EI 1607-8489 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1997 VL 17 IS 1-4 BP 231 EP 246 DI 10.1080/10584589708012998 PG 16 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA YF222 UT WOS:A1997YF22200024 ER PT J AU Cherry, HB Haller, EE Reade, RP Beeman, JW Hubbard, GS McMurray, RE AF Cherry, HB Haller, EE Reade, RP Beeman, JW Hubbard, GS McMurray, RE TI Potassium tantalate niobate thin films for spaceborne pyroelectric detectors SO INTEGRATED FERROELECTRICS LA English DT Article AB Potassium tantalate niobate (KTN) thin film pyroelectric detectors are being developed for broad band spaceborne sensors where passively cooled operating temperatures similar to 90K are easily attained. The ability to tailor the phase transition temperature of KTN through composition control makes it an ideal candidate for such applications. Decreasing the operating temperature from 300K to 90K allows for over an order of magnitude increase in the background-limited sensitivity of a pyroelectric detector. Current research focuses on optimizing the composition and structure of laser deposited KTa0.91Nb0.09O3 (T-c = 93K) thin films. Preliminary studies of materials for bottom electrodes are being performed using Pt and conducting oxides with the perovskite structure: La0.5Sr0.5CoO3 (LSC), YBa2Cu3O7-partial derivative (YBCO) and SrRuO3. KTN films have been grown by pulsed laser deposition on LaAlO3, Pt/Si3N4/Si, LSC/LaAlO3, YBCO/SrTiO3, YBCO/LaAlO3, and YBCO/YSZ (yttria-stabilized ZrO2) substrates and heterostructures. The highest quality KTN films on (100)-pseudocubic LaAlO3 are grown at PO2 = 300-400 mTorr and 650-750 degrees C exhibit in and out of plane orientation. The FWHM rocking curves of these films vary from 0.43-0.73 degrees. The presence of undesirable pyrochlore phase, as evidenced by X-ray Diffraction, can be eliminated at partial oxygen pressures of 300 and 400 mTorr. Initially a potassium deficiency of 40-50% was measured in films using Rutherford Backscattering Spectrometry and X-ray Photoelectron Spectroscopy. This deficiency is eliminated by using a potassium enriched (117%) fully reacted ceramic target in addition to growing in higher oxygen partial pressures (400 mTorr). Devices have been fabricated from Pt, LSC and YBCO bottom electrode heterostructures. Results from these structures are discussed. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Cherry, HB (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 8 TC 1 Z9 1 U1 2 U2 3 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1997 VL 15 IS 1-4 BP 261 EP 269 DI 10.1080/10584589708015717 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA WR715 UT WOS:A1997WR71500028 ER PT J AU Miranda, FA Mueller, CH Treece, RE Rivkin, TV Thompson, JB Moutinho, HR Dalberth, M Rogers, CT AF Miranda, FA Mueller, CH Treece, RE Rivkin, TV Thompson, JB Moutinho, HR Dalberth, M Rogers, CT TI Effect of SrTiO3 deposition temperature on the dielectric properties of SrTiO3/YBa2Cu3O7-delta/LaAlO3 structures SO INTEGRATED FERROELECTRICS LA English DT Article; Proceedings Paper CT 8th International Symposium on Integrated Ferroelectrics CY MAR 18-20, 1996 CL TEMPE, AZ SP Naval Postgrad Sch, Univ Colorado, Motorola, Gordon & Breach Sci Publ, Texas Instruments, Tegal Corp ID THIN-FILMS AB We report on the effect of the deposition temperature of SrTiO3 on the dielectric properties of SrTiO3/YBa2Cu3O7-delta/LaAlO3 thin film multilayer structures. In these structures, the YBa2Cu3O7-delta (YBCO) films were deposited at 800 degrees C by laser ablation, followed by the in-situ deposition of the SrTiO3 (STO) layer at one of the following temperatures: 750 degrees C, 650 degrees C, 550 degrees C, 450 degrees C, 350 degrees C, and 250 degrees C. Gold (Au) films were deposited and patterned on top of the STO layer to form planar Au/STO/YBCO capacitor structures. The electrical response was studied by measuring the dielectric constant (epsilon(r)) and loss tangent (tan delta) of the ferroelectric film from 300-40 K, at 1.0 MHz, and at electric fields up to 100 kV/cm. Our results show 750 degrees C to be a deposition temperature which allows for large variations of epsilon(r) with applied field, and with limited enhancement of tan delta. Lower deposition temperatures cause a reduction of the induced change in epsilon(r) and an increase in tan delta with applied field. C1 SUPERCONDUCTING CORE TECHNOL,GOLDEN,CO 80401. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. UNIV COLORADO,BOULDER,CO 80309. RP Miranda, FA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 14 TC 10 Z9 10 U1 0 U2 2 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 1058-4587 J9 INTEGR FERROELECTR JI Integr. Ferroelectr. PY 1997 VL 14 IS 1-4 BP 173 EP 180 DI 10.1080/10584589708019990 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA WR714 UT WOS:A1997WR71400021 ER PT B AU Flood, DJ AF Flood, DJ GP IEEE IEEE IEEE TI Satellite solar energy systems SO INTELEC 97 - 19TH INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE, PROCEEDINGS: POWER AND ENERGY SYSTEMS IN CONVERGING MARKETS LA English DT Meeting Abstract CT 19th International Telecommunications Energy Conference (Intelec 97) CY OCT 19-23, 1997 CL MELBOURNE, AUSTRALIA SP IEEE, IEEE, Power Electr Soc, COM10, GNB Technol, Hawker Batteries, M&H Power Syst, Telstra Corp, Austr Tourist Commiss, MGE UPS Syst, Battery Energy S Pacific, FIAMM, Whats New Magazines C1 NASA, Lewis Res Ctr, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-3997-5 PY 1997 BP 12 EP 12 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA BK12N UT WOS:000071242800003 ER PT B AU Flood, DJ AF Flood, DJ GP IEEE IEEE IEEE TI Advanced space photovoltaic technology: Applications to telecommunication systems SO INTELEC 97 - 19TH INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE, PROCEEDINGS: POWER AND ENERGY SYSTEMS IN CONVERGING MARKETS LA English DT Proceedings Paper CT 19th International Telecommunications Energy Conference (Intelec 97) CY OCT 19-23, 1997 CL MELBOURNE, AUSTRALIA SP IEEE, IEEE, Power Electr Soc, COM10, GNB Technol, Hawker Batteries, M&H Power Syst, Telstra Corp, Austr Tourist Commiss, MGE UPS Syst, Battery Energy S Pacific, FIAMM, Whats New Magazines AB For nearly two decades, most NASA and commercial space power systems were typically in the 1 to 2 kilowatt range. Now, however, the demand for more power per unit mass and area of satellite solar arrays is rising dramatically, driven entirely by the telecommunications industry and some U.S. military applications. Commercial satellites with power system capabilities exceeding 10 kilowatts have already been launched, and hundreds more are in the planning stages. At the same time, however, NASA mission programs are striving for smaller, more specialized spacecraft which can still achieve complex mission objectives, but at lower total mission cost. These apparently divergent sets of requirements are surprisingly synergistic: both place a high priority on developing power systems with high efficiency, low mass and long life in the space environment. Key elements of the near term NASA advanced technology program include (1) development and eventual commercial production of multibandgap (MEG) solar cells with air mass zero (AM0) efficiencies approaching 30%; (2) commercial availability of a flight qualified concentrator solar array with superior lifetime and lower cost than conventional planar solar arrays. For the far term, the program is focussed on development of ultra lightweight, thin film solar arrays. The potential impact of all these technologies on telecommunication satellites will discussed. C1 NASA, Lewis Res Ctr, Space Environm Branch MS3021, Cleveland, OH 44135 USA. RP Flood, DJ (reprint author), NASA, Lewis Res Ctr, Space Environm Branch MS3021, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-3997-5 PY 1997 BP 647 EP 652 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA BK12N UT WOS:000071242800102 ER PT B AU Schenker, PS Sword, LF Ganino, AJ Bickler, DB Hickey, GS Brown, DK Baumgartner, ET Matthies, LH Wilcox, BH Balch, T Aghazarian, H Garrett, MS AF Schenker, PS Sword, LF Ganino, AJ Bickler, DB Hickey, GS Brown, DK Baumgartner, ET Matthies, LH Wilcox, BH Balch, T Aghazarian, H Garrett, MS BE Casasent, DP TI Lightweight rovers for Mars science exploration and sample return SO INTELLIGENT ROBOTS AND COMPUTER VISION XVI: ALGORITHMS, TECHNIQUES, ACTIVE VISION, AND MATERIALS HANDLING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Intelligent Robots and Computer Vision XVI - Algorithms, Techniques, Active Vision, and Materials Handling CY OCT 15-17, 1997 CL PITTSBURGH, PA SP Soc Photo Opt Instrumentat Engineers, NIST, Coalit Intelligent Mfg Syst, Acad Coalit Intelligent Mfg Syst DE mobile robots; 3D sensing; robotic sampling; planetary science; Mars sample return AB We report on the development of new mobile robots for Mars exploration missions. These ''lightweight survivable rover (LSR)'' systems are of potential interest to both space and terrestrial applications, and ape distinguished from more conventional designs by their use of new composite materials, collapsible running gear, integrated thermal-structural chassis, and other mechanical features enabling improved mobility and environmental robustness at reduced mass, volume, and power. Our first demonstrated such rover architecture, LSR-1, introduces running gear based on 2D composite struts and 3D machined composite joints, a navel collapsible hybrid composite-aluminum wheel design, a unit-body structural-thermal chassis with improved internal temperature isolation and stabilization, and a spot-pushbroom laser/CCD sensor enabling accurate, fast hazard detection and terrain mapping. LSR-1 is a similar to .7 x 1.0 meter(Lambda)2(WxL) footprint six-wheel (20 cm dia.) rocker-bogie geometry vehicle of similar to 30 cm ground clearance, weighing only 7 kilograms with an onboard 3 kilogram multi-spectral imager and spectroscopic photometer. By comparison, NASA/JPL's recently flown Mars Pathfinder rover Sojourner is an 11+ kilogram flight experiment (carrying a 1 kg APXS instrument) having similar to .45 x.6 meter(Lambda)2 (WxL) footprint and 15 cm ground clearance, and about half the warm electronics enclosure (WEE) volume with twice the diurnal temperature swing (-40 to +40 degrees C) of LSR-1 in nominal Mars environments. We are also developing a new, smaller 5 kilogram class LSR-type vehicle for Mars sample return - the travel to, localization of, pick-up, and transport back to an Earth return ascent vehicle of a sample cache collected by earlier science missions. This Sample Retrieval Rover R&D prototype has a. completely collapsible mobility system enabling rover stowage to similar to 25% operational volume, as well an actively articulated axle, allowing changeable pose of the wheel strut geometry for improved traverse and manipulation characteristics. RP Schenker, PS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 125-224,PASADENA,CA 91109, USA. NR 0 TC 7 Z9 7 U1 1 U2 7 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2640-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3208 BP 24 EP 36 DI 10.1117/12.290300 PG 13 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Optics SC Automation & Control Systems; Computer Science; Optics GA BJ68N UT WOS:A1997BJ68N00003 ER PT B AU Schenker, PS Baumgartner, ET Lee, S Aghazarian, H Garrett, MS Lindemann, RA Brown, DK BarCohen, Y Lih, SS Joffe, B Kim, SS Hoffman, BH Huntsberger, T AF Schenker, PS Baumgartner, ET Lee, S Aghazarian, H Garrett, MS Lindemann, RA Brown, DK BarCohen, Y Lih, SS Joffe, B Kim, SS Hoffman, BH Huntsberger, T BE Casasent, DP TI Dexterous robotic sampling for Mars in-situ science SO INTELLIGENT ROBOTS AND COMPUTER VISION XVI: ALGORITHMS, TECHNIQUES, ACTIVE VISION, AND MATERIALS HANDLING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Intelligent Robots and Computer Vision XVI - Algorithms, Techniques, Active Vision, and Materials Handling CY OCT 15-17, 1997 CL PITTSBURGH, PA SP Soc Photo Opt Instrumentat Engineers, NIST, Coalit Intelligent Mfg Syst, Acad Coalit Intelligent Mfg Syst DE space robotics; manipulators; intelligent control; mobile robots; planetary sampling; Mars sample return AB Robotic exploration of the Martian surface will provide important scientific data on planetary climate, life history, and geologic resources. Ln particular, robotic arms will assist in the detailed visual inspection, instrumented analysis, extraction, and earth return of soil and rock samples. To this end, we are developing new robotic manipulation concepts for use on landers and rovers, wherein mass, volume, power and the ambient Mars environment are significant design constraints. Our earlier work led to MarsArmI, a 2.2 meter, 3-d.o.f. hybrid metal/composite, DC-motor actuated arm operating under coordinated joint-space control; NASA's Mars Surveyor '98 mission utilizes this design concept More recently, we have conceived and implemented new, all-composite, very light robot arms: MarsArmII, a 4.0 kilogram, 2.3 meter arm for lander operations, and MicroArm-I and MicroArm-2, two smaller 1.0+ kilogram, .7 meter rover arms for mobile sample acquisition and Mars sample return processing. Features of these arms include our creation of new 3D machined composites for critical load-bearing parts; actuation by high-torque density ultrasonic motors; and visually-designated inverse kinematics positioning with contact force adaptation under a novel task-level, dexterous controls paradigm, Our demonstrated results include robotic trenching, sample grasp-manipulation-and-transfer, and fresh rock surface exposure-probing via the science operator's ''point-and-shoot'' visual task designation in a stereo workspace. Sensor-referenced control capabilities include red-time adaptation to positioning error and environmental uncertainties (e.g., variable soil resistance and impediments), and the synthesis of power optimal trajectories for free space manipulation. RP Schenker, PS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 125-224,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2640-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3208 BP 170 EP 185 DI 10.1117/12.290290 PG 16 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Optics SC Automation & Control Systems; Computer Science; Optics GA BJ68N UT WOS:A1997BJ68N00019 ER PT S AU Hepp, AE Fatemi, NS Wilt, DM Ferguson, DC Hoffman, RW Hill, MM AF Hepp, AE Fatemi, NS Wilt, DM Ferguson, DC Hoffman, RW Hill, MM BE Briant, CL Carter, CB Hall, EL TI Wheel abrasion experiment metals selection for Mars Pathfinder Mission SO INTERFACIAL ENGINEERING FOR OPTIMIZED PROPERTIES SE MATERIALS RESEARCH SOCIETY CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Interfacial Engineering for Optimized Properties CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc AB A series of metals was examined for suitability for the Wheel Abrasion Experiment, one of ten microrover experiments of the Mars Pathfinder Mission. The seven candidate metals were: Ag, Al, Au, Cu, Ni, Pt, and W. Thin films of candidate metals from 0.1 to 1.0 micrometer thick were deposited on black anodized aluminum coupons by e-beam and resistive evaporation and chemical vapor deposition. Optical, corrosion, abrasion, and adhesion criteria were used to select Al, Ni, and Pt. A description is given of the deposition and testing of thin films, followed by a presentation of experimental data and a brief discussion of follow-on testing and flight qualification. RP Hepp, AE (reprint author), NASA,LEWIS RES CTR,MS 302 1,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0886-7860 BN 1-55899-362-2 J9 MAT RES S C PY 1997 VL 458 BP 231 EP 236 PG 6 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Materials Science GA BJ28D UT WOS:A1997BJ28D00033 ER PT J AU Whittenberger, JD Noebe, RD Johnson, DR Oliver, BF AF Whittenberger, JD Noebe, RD Johnson, DR Oliver, BF TI Compressive and tensile creep of a directionally solidified NiAl-14.5(at%)Ta alloy SO INTERMETALLICS LA English DT Article DE nickel aluminide; based on NiAl; multiphase intermetallics; Laves phase; creep; mechanical properties at high temperature ID IN-SITU COMPOSITES; MECHANICAL-PROPERTIES; SYSTEMS AB Three directionally solidified (DS'ed) bars of NiAl-14.5(at%)Ta possessing a non-uniform distribution of approximately 10 vol% of dendritic NiAl in a lamellar NiAl and NiAlTa eutectic mixture have been tested in air at elevated temperatures. Samples from two bars were subjected to constant velocity and constant load compression testing between 1200 and 1400 K, while specimens cut from the third bar were creep rupture tested in tension at 1200 and 1300 K. Although a number of samples failed on loading at 1200 K, five successful tensile creep tests were conducted with elongations of 10% or more prior to failure. A Larson-Miller analysis indicated that the stress rupture properties of DS'ed NiAl-14.5Ta were equivalent to the Ni-based superalloy Rene80 and better than those of first generation NiAl-based single crystals and a particulate AlN reinforced NiAl. In spite of the inhomogeneous microstructure, no dependency on either test mode or bar of material was found in the flow stress-strain rate-temperature properties. Comparison of the 1300 and 1400 K creep properties of several directionally solidified NiAl-based alloys indicated that DS'ed NiAl-14.5Ta is one of the strongest materials studied to date; however, its inherent brittleness, as reflected by a low room temperature fracture toughness and high brittle to ductile transition temperature (BDTT), appear to limit its usefulness. (C) 1997 Elsevier Science Ltd. C1 KYOTO UNIV,SAKYO KU,KYOTO 606,JAPAN. UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996. RP Whittenberger, JD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 15 TC 26 Z9 26 U1 4 U2 18 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0966-9795 J9 INTERMETALLICS JI Intermetallics PY 1997 VL 5 IS 3 BP 173 EP 183 DI 10.1016/S0966-9795(96)00078-7 PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA WK734 UT WOS:A1997WK73400002 ER PT S AU Fang, WC Yang, G Pain, B Sheu, BJ AF Fang, WC Yang, G Pain, B Sheu, BJ GP IEEE COMP SOC TI A low power smart vision system based on active pixel sensor integrated with programmable neural processor SO INTERNATIONAL CONFERENCE ON COMPUTER DESIGN - VLSI IN COMPUTERS AND PROCESSORS, PROCEEDINGS SE PROCEEDINGS - IEEE INTERNATIONAL CONFERENCE ON COMPUTER DESIGN LA English DT Proceedings Paper CT International Conference on Computer Design - VLSI in Computers and Processors (ICCD 97) CY OCT 12-15, 1997 CL AUSTIN, TX SP IEEE Comp Soc, Tech Comm Design Automat, IEEE Circuits & Syst Soc AB A low power smart vision system based on a large format (currently 1Kx1K) active pixel sensor (APS) integrated with a programmable neural processor for fast vision applications is presented. The concept of building a low power smart vision system is demonstrated by a system design which is composed with an APS sensor, a smart image window handler, and a neural processor. The paper also shows that it is feasible to put the whole smart vision system into a single chip in a standard CMOS technology. This smart vision system on-a-chip can take the combined advantages of the optics and electronics to achieve ultra-high-speed smart sensory information processing and analysis at the focal plane. The proposed system will enable many applications including robotics and machine vision, guidance and navigation, automotive applications, and consumer electronics. Future applications will also include scientific sensors such as those suitable for highly integrated imaging systems used in NASA deep space and planetary spacecraft. RP Fang, WC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1063-6404 BN 0-8186-8207-8 J9 PR IEEE COMP DESIGN PY 1997 BP 429 EP 434 DI 10.1109/ICCD.1997.628905 PG 6 WC Computer Science, Hardware & Architecture SC Computer Science GA BJ80H UT WOS:A1997BJ80H00061 ER PT B AU Matthies, L Chen, B Petrescu, J AF Matthies, L Chen, B Petrescu, J GP IEEE SIGNAL PROC SOC TI Stereo vision, residual image processing and Mars rover localization SO INTERNATIONAL CONFERENCE ON IMAGE PROCESSING - PROCEEDINGS, VOL III LA English DT Proceedings Paper CT International Conference on Image Processing CY OCT 26-29, 1997 CL SANTA BARBARA, CA SP IEEE Signal Proc Soc DE stereo vision; Mars rover localization; random fields; segmentation; clustering AB Experiments had been conducted on Mars rover detection and localization using residue image processing and stereo vision. in NASA's Pathfinder mission. an unmanned lander had been landed on Mars and a microrover was released from the lander to perform scientific experiments. Rover localization is an important issue because, for navigation purpose, the rover's position needs to be continuously updated. Three aspects of the problem have been studied: motion detection, residue image processing, and range estimation. The algorithms are described in this paper. Stereo-pairs of images taken at Jet Propulsion's Laboratory's (JPL's) Mars Test Arena were used to test the algorithms. The results were presented along with analysis of range estimation accuracy. RP Matthies, L (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8183-7 PY 1997 BP 248 EP 251 PG 4 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BJ90D UT WOS:A1997BJ90D00064 ER PT B AU Turmon, MJ Mukhtar, S AF Turmon, MJ Mukhtar, S GP IEEE SIGNAL PROC SOC TI Recognizing chromospheric objects via Markov chain Monte Carlo SO INTERNATIONAL CONFERENCE ON IMAGE PROCESSING - PROCEEDINGS, VOL III LA English DT Proceedings Paper CT International Conference on Image Processing CY OCT 26-29, 1997 CL SANTA BARBARA, CA SP IEEE Signal Proc Soc AB The solar chromosphere consists of three classes which contribute differentially to ultraviolet radiation reaching the earth. We describe a data set of solar images, means of segmenting the images into the constituent classes, and a novel high-level representation for compact objects based on a triangulated spatial 'membership function.' Such representations are fitted in a variable-dimension Markov chain Monte Carlo scheme. RP Turmon, MJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8183-7 PY 1997 BP 320 EP 323 PG 4 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BJ90D UT WOS:A1997BJ90D00082 ER PT B AU Yan, JC AF Yan, JC BE Arabnia, HR TI By hand or not by-hand - A case study of computer aided parallelization tools for CFD applications SO INTERNATIONAL CONFERENCE ON PARALLEL AND DISTRIBUTED PROCESSING TECHNIQUES AND APPLICATIONS, VOLS I-III, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 97) CY JUN 30-JUL 03, 1997 CL LAS VEGAS, NV SP Comp Sci Res, Educ & Applicat Tech, N Amer Transputer Users Grp, Comp Vis Res & Applicat Tech, US DOE, Natl Super Comp Ctr Energy & Environm DE parallel processing; performance evaluation; computer-aided parallelization AB Scientists at NASA Ames have been. developing multidisciplinary applications on highly parallel architectures over the past ten years. During the same time period, a steady transition of hardware and system software took place, forcing us to expand great efforts into migrating and re-coding our applications. As applications and machine architectures become increasingly complex, the cost and time required for this process will become prohibitive. Various attempts to exploit software tools to assist and automate the parallelization process have not produced favorable results. This paper presents our recent experiences with CAPTools. In particular, the performance of CAPTooLs generated code was compared against three handwritten. NAS Parallel Benchmarks: LU, BT, and SP. In one case, CAPTools was able to generate code within 5% of hand-written MPI code. Based on, these favorable results obtained, CAPTooLs will be applied on some full-scale aerodynamic solvers in the coming year. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP Yan, JC (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, MS T27A-1, Moffett Field, CA 94035 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU C S R E A PRESS PI ATHENS PA 115 AVALON DR, ATHENS, GA 30606 USA BN 0-9648666-8-4 PY 1997 BP 364 EP 372 PG 9 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BR81J UT WOS:000167624100045 ER PT J AU De Vantier, BA Finn, JE AF De Vantier, BA Finn, JE TI Discrete dispersion relations and Taylor-Galerkin FEM for transport of dispersed fronts SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE finite elements; adsorption; Taylor-Galerkin method; dispersed fronts ID INCOMPRESSIBLE FLOWS AB A time and space accurate method for computing the movement of an adsorbing contaminant in a carrier fluid is presented. The method uses a finite element analog to a previously described finite difference approach which can accurately describe movement of highly convected, but dispersing fronts. An operator splitting scheme between convection and dispersion is employed which provides fourth order time accuracy on the convection step. The higher accuracy for the convection step is also accompanied with better mass conservation properties than is common for most algorithms which model purely convective problems. The method is demonstrated on problems varying in one dimension by applications to pure convection-dispersion, the nonlinear Burger's equation, convection-reaction equations, and convection-dispersion through an adsorbing medium. The model predictions are found to provide accurate and stable results. C1 So Illinois Univ, Dept Civil Engn & Mech, Carbondale, IL 62901 USA. NASA, Regenerat Life Support Syst Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. RP De Vantier, BA (reprint author), So Illinois Univ, Dept Civil Engn & Mech, Carbondale, IL 62901 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1997 VL 9 IS 1 BP 59 EP 70 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YQ976 UT WOS:000071444100004 ER PT J AU Morano, E Mavriplis, DJ AF Morano, E Mavriplis, DJ TI Implementation of a parallel unstructured 3D Euler solver on the CM-5 SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE parallel computing; CM-5 architecture; 3D Euler solver; unstructured grids AB An unstructured 3D Euler solver is parallelized on a Thinking Machine Corporation Connection Machine 5, distributed memory computer with vectorizing capability. In this paper, the SIMD strategy is employed through the use of the CM Fortran language and the CMSSL scientific library. The performance of the CMSSL mesh partitioner is evaluated and the overall efficiency of the parallel flow solver is discussed. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. RP Morano, E (reprint author), UNIV HOUSTON,DEPT MATH,HOUSTON,TX 77204, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1997 VL 8 IS 2 BP 93 EP 98 DI 10.1080/10618569708940797 PG 6 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA XE474 UT WOS:A1997XE47400002 ER PT J AU Mavriplis, DJ Venkatakrishnan, V AF Mavriplis, DJ Venkatakrishnan, V TI A unified multigrid solver for the Navier-Stokes equations on mixed element meshes SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE multigrid; unstructured grids; Navier-Stokes ID EULER EQUATIONS; UNSTRUCTURED MESHES; AGGLOMERATION; FLOWS AB A unified multigrid solution technique is presented for solving the Euler and Reynolds-averaged Navier-Stokes equations on unstructured meshes using mixed elements consisting of triangles and quadrilaterals in two dimensions, and of hexahedra, pyramids, prisms and tetrahedral in three dimensions. While the use of mixed elements is by no means a novel idea, the contribution of the paper lies in the formulation of a complete solution technique which can handle structured grids, block structured grids, and unstructured grids of tetrahedra or mixed elements without any modification. This is achieved by discretizing the full Navier-Stokes equations on tetrahedral elements, and the thin layer version of these equations on other types of elements, while using a single edge-based data-structure to construct the discretization over all element types. An agglomeration multigrid algorithm, which naturally handles meshes of any types of elements, is employed to accelerate convergence. An automatic algorithm which reduces the complexity of a given triangular or tetrahedral mesh by merging candidate triangular or tetrahedral elements into quadrilateral or prismatic elements is also described. The gains in computational efficiency afforded by the use of non-simplicial meshes over fully tetrahedral meshes are demonstrated through several examples. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP Mavriplis, DJ (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. NR 31 TC 27 Z9 27 U1 1 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1997 VL 8 IS 4 BP 247 EP 263 DI 10.1080/10618569708940807 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YQ112 UT WOS:000071349700002 ER PT J AU Yee, HC Sweby, PK AF Yee, HC Sweby, PK TI On spurious behavior of super-stable implicit methods SO INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS LA English DT Article DE super-stable; implicit methods; linear multistep methods; TVD schemes; total variation diminishing schemes; grid adaptation; spurious solutions ID NONLINEAR DIFFERENTIAL-EQUATIONS; STATE NUMERICAL-SOLUTIONS; MULTIPLE STEADY-STATES; INITIAL-VALUE PROBLEMS; STABILITY; DYNAMICS; SCHEMES AB The objective of this paper is to gain a better understanding of the asymptotic nonlinear behavior of super-stable implicit linear multistep methods for constant time steps. Examples of the nonlinear effect caused by grid adaptation and super-stable implicit total variation diminishing (TVD) schemes on the overall performance of the numerical procedure are given. A method to minimize spurious steady-state numerical solutions is discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Reading, Reading RG6 2AX, Berks, England. RP Yee, HC (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 42 TC 2 Z9 2 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1061-8562 J9 INT J COMPUT FLUID D JI Int. J. Comput. Fluid Dyn. PY 1997 VL 8 IS 4 BP 265 EP + DI 10.1080/10618569708940808 PG 31 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YQ112 UT WOS:000071349700003 ER PT J AU Lewicki, DG Ballarini, R AF Lewicki, DG Ballarini, R TI Rim thickness effects on gear crack propagation life SO INTERNATIONAL JOURNAL OF FRACTURE LA English DT Article DE rims; crack propagation; crack growth; gears; fracture mechanics; finite element modeling; stress intensity; factors ID TOOTH AB Analytical and experimental studies were performed to investigate the effect of gear rim thickness on crack propagation life. The FRANC (FRacture ANalysis Code) computer program was used to simulate crack propagation. The FRANC program used principles of linear elastic fracture mechanics, finite element modeling, and a unique re-meshing scheme to determine crack tip stress distributions, estimate stress intensity factors, and model crack propagation. Various fatigue crack growth models were used to estimate crack propagation life based on the calculated stress intensity factors. Experimental tests were performed in a gear fatigue rig to validate predicted crack propagation results. Test gears were installed with special crack propagation gages in the tooth fillet region to measure bending fatigue crack growth. Good correlation between predicted and measured crack growth was achieved when the fatigue crack closure concept was introduced into the analysis. As the gear rim thickness decreased, the compressive cyclic stress in the gear tooth fillet region increased. This retarded crack growth and increased the number of crack propagation cycles to failure. C1 NASA, USA, Res Lab, Vehicle Propuls Directorate,Langley Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Civil Engn, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. RP Lewicki, DG (reprint author), NASA, USA, Res Lab, Vehicle Propuls Directorate,Langley Res Ctr, Cleveland, OH 44135 USA. NR 33 TC 28 Z9 31 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0376-9429 J9 INT J FRACTURE JI Int. J. Fract. PY 1997 VL 87 IS 1 BP 59 EP 86 DI 10.1023/A:1007368801853 PG 28 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA ZC473 UT WOS:000072582800004 ER PT J AU Mostafa, I Hailu, S Welsch, G Hazony, D Halford, GR AF Mostafa, I Hailu, S Welsch, G Hazony, D Halford, GR TI Detection and measurement of fatigue crack in HSLA steel with a dedicated ultrasonic pulse transmission method SO INTERNATIONAL JOURNAL OF FRACTURE LA English DT Article AB A dedicated 'ultrasound transmission' method was used for detection of fatigue cracks. The measurements were done in-situ on hourglass-shaped specimens of HSLA steel that had piezoelectric transducers embedded in each end. Time-limited pulses were emitted from one transducer and received by the other. Longitudinal and surface waves resulted from each pulse and were monitored with a storage oscilloscope. During fatigue cycling between zero and a constant tensile load, the changes in the rime-of-flight and in the transmitted amplitudes of the ultrasonic waves were used to monitor the elastic and plastic strains in order to detect fatigue damage and crack initiation. During the initial fatigue cycles, a decrease in the transmitted wave amplitude occurred due to plastic deformation. In subsequent cycles, during which the stress-strain hysteresis loops indicated essentially zero plastic strain, the transmitted wave amplitudes remained constant. Eventually, a fatigue crack nucleated and grew. This was detected by a decrease of the transmitted wave amplitudes. From here on, further decrease of the transmitted amplitudes measured the crack growth. Crack growth was also measured from marked crack fronts in the final fracture surface. The entire history of fatigue damage evolution from initial strain hardening, through strain saturation, crack nucleation and growth could be monitored with the present technique. C1 Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Elect Engn & Appl Phys, Cleveland, OH 44106 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Mostafa, I (reprint author), Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. NR 20 TC 2 Z9 2 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0376-9429 J9 INT J FRACTURE JI Int. J. Fract. PY 1997 VL 85 IS 2 BP 99 EP 109 DI 10.1023/A:1007490423869 PG 11 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA YN383 UT WOS:000071163100001 ER PT J AU Buyevich, YA Webbon, BW AF Buyevich, YA Webbon, BW TI The isolated bubble regime in pool nucleate boiling SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID CRITICAL HEAT-FLUX; POWER TRANSIENTS; PREDICTION; THICKNESS; MODEL AB We consider an isolated bubble boiling regime in which vapour bubbles are intermittently produced at a prearranged set of nucleation sites on an upward facing overheated wall plane. In this boiling regime, the bubbles depart from the wall and move as separate entities. Heat transfer properties specific to this regime cannot be described without bubble detachment size, and we apply our previously developed dynamic theory of vapour bubble growth and detachment to determine this size. Bubble growth is presumed to be thermally controlled. Two limiting cases of bubble evolution are considered: the one in which buoyancy prevails in promoting bubble detachment and the one in which surface tension prevails. We prove termination of the isolated regime of pool nucleate boiling to result from one of the four possible causes, depending on relevant parameters values. The first cause consists in the fact that the upward flow of rising bubbles hampers the downward liquid flow, and under certain conditions, prevents the liquid from coming to the wail in an amount that would be sufficient to compensate for vapour removal from the wall. The second cause is due to the lateral coalescence of growing bubbles that are attached to their corresponding nucleation sites, with ensuing generation of larger bubbles and extended vapour patches near the wall. The other two causes involve longitudinal coalescence either: (1) immediately in the wall vicinity, accompanied by the establishment of the multiple bubble boiling regime or (2) in the bulk, with the formation of vapour columns. The longitudinal coalescence in the bulk is shown to be the most important cause. The critical wall temperature and the heat flux density associated with isolated bubble regime termination are found to be functions of the physical and operating parameters and are discussed in detail. Copyright (C) 1996 Elsevier Science Ltd. RP Buyevich, YA (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 34 TC 8 Z9 8 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD JAN PY 1997 VL 40 IS 2 BP 365 EP 377 DI 10.1016/0017-9310(96)00097-X PG 13 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA VM848 UT WOS:A1997VM84800012 ER PT J AU Garg, VK Gaugler, RE AF Garg, VK Gaugler, RE TI Effect of coolant temperature and mass flow on film cooling of turbine blades SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID JET AB A three-dimensional Navier-Stokes code has been used to study the effect of coolant temperature, and coolant to mainstream mass flow ratio on the adiabatic effectiveness of a film-cooled turbine blade. The blade chosen is the VKI rotor with six rows of cooling holes including three rows on the shower head. The mainstream is akin to that under real engine conditions with stagnation temperature = 1900K and stagnation pressure = 3 MPa. Generally, the adiabatic effectiveness is lower for a higher coolant temperature due to nonlinear effects via the compressibility of air. However, over the suction side of shower-head holes, the effectiveness is higher for a higher coolant temperature than that for a lower coolant temperature when the coolant to mainstream mass flow ratio is 5% or more. For a fixed coolant temperature, the effectiveness passes through a minima on the suction side of shower-head holes as the coolant to mainstream mass flow ratio increases, while on the pressure side of shower-head holes, the effectiveness decreases with increase in coolant mass flow due to coolant jet lift-off. In all cases, the adiabatic effectiveness is highly three-dimensional. Copyright (C) 1996 Elsevier Science Ltd. C1 NASA,LEWIS RES CTR,TURBOMACHINERY FLOW PHYS BRANCH,INTERNAL FLUID MECH DIV,CLEVELAND,OH 44135. NR 22 TC 25 Z9 28 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD JAN PY 1997 VL 40 IS 2 BP 435 EP 445 DI 10.1016/0017-9310(96)00040-3 PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA VM848 UT WOS:A1997VM84800017 ER PT J AU Bernhard, RP Christiansen, EL Kessler, DE AF Bernhard, RP Christiansen, EL Kessler, DE TI Orbital debris as detected on exposed spacecraft SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY AB Spacecraft surfaces returned to the laboratory after being exposed to the low Earth orbit (LEO) environment have been examined by Scanning Electron Microscopy and Energy Dispersive X-ray (SEM/EDX) over the last two decades. Although many of these surfaces were not intended to be used as hypervelocity impact capture medium, meteoroid and orbital debris particles colliding with exposed surfaces are well documented. This paper will address the more predominant impact damage caused by orbital debris on the spacecraft hardware analyzed at the Johnson Space Center over the last decade. C1 NASA,EARTH SCI & SOLAR SYST EXPLORAT DIV,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP Bernhard, RP (reprint author), LOCKHEED MARTIN,C23,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 23 TC 11 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 111 EP 120 DI 10.1016/S0734-743X(97)87485-4 PG 10 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800013 ER PT J AU Bogdanoff, DW AF Bogdanoff, DW TI Optimization study of the Ames 0.5'' two-stage light gas gun SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY AB There is a need for more faithful simulation of space debris impacts on various space vehicles. Space debris impact velocities can range up to 14 km/sec and conventional two-stage light gas guns with moderately heavy saboted projectiles are limited to launch velocities of 7-8 km/sec. Any increases obtained in the launch velocities will result in more faithful simulations of debris impacts. It would also be valuable to reduce the maximum gun and projectile base pressures and the gun barrel erosion rate. In this paper, the results of a CFD study designed to optimize the performance of the NASA Ames 0.5 '' gun by systematically varying seven gun operating parameters are reported. The optimum set of changes in gun operating conditions were predicted to produce an increase in muzzle velocity of 0.7 - 1.0 km/sec, simultaneously with a substantial decrease in gun erosion. Preliminary experimental data have validated the code predictions. RP Bogdanoff, DW (reprint author), NASA,THERMOSCI INST,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 8 TC 6 Z9 7 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 131 EP 142 DI 10.1016/S0734-743X(97)87487-8 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800015 ER PT J AU Christiansen, EL Friesen, L AF Christiansen, EL Friesen, L TI Penetration equations for thermal protection materials SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY AB NASA has developed a number of penetration equations for a broad range of thermal protection system (TPS) materials used on the Space Shuttle Orbiter and other spacecraft including low-density ceramic tiles, reinforced carbon-carbon, flexible ceramic insulation and multi-layer insulation (MLI). The penetration equations describe the penetration depth or damage extent to be expected from hypervelocity particles as a function of projectile velocity, size, density, and various target parameters including thickness and configuration. ''Ballistic limit'' equations have also been developed to define projectile conditions causing threshold perforation of more complex targets that combine an outer TPS material with an underlying structural element such as a ceramic tile bended to an aluminum plate. These equations were developed from hypervelocity impact data collected at the NASA Johnson Space Center (JSC) Hypervelocity Impact Test Facility (HIT-F). C1 LOCKHEED MARTIN,LYNDON B JOHNSON SPACE CTR,HITF,HOUSTON,TX 77058. RP Christiansen, EL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN3,HOUSTON,TX 77058, USA. NR 13 TC 24 Z9 26 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 153 EP 164 DI 10.1016/S0734-743X(97)87489-1 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800017 ER PT J AU Christiansen, EL Kerr, JH AF Christiansen, EL Kerr, JH TI Projectile shape effects on shielding performance at 7 km/s and 11 km/s SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY ID IMPACTS AB NASA has developed enhanced performance shields to improve the protection of spacecraft from orbital debris and meteoroid impacts. One of these enhanced shields includes a blanket of Nextel(TM) ceramic fabric and Kevlar(TM) high strength fabric that is positioned midway between an aluminum bumper and the spacecraft pressure wall. As part of the evaluation of this new shielding technology, impact data above 10 km/sec have been obtained by NASA Johnson Space Center (JSC) from the Sandia National Laboratories HVL (''hypervelocity launcher'') and the Southwest Research Institute inhibited shaped charge launcher (ISCL). The HVL launches flyer-plates in the velocity range of 10 to 15 km/s while the ISCL launches hollow cylinders at similar to 11.5 km/s. The >10 km/s experiments are complemented by hydrocode analysis and light-gas gun testing at the JSC Hypervelocity Impact Test Facility (HIT-F) to assess the effects of projectile shape on shield performance. Results from the testing and analysis indicate that nonspherical shapes are more penetrating than equal mass spheres (by factors of 1.2 to similar to 2). Impact data also demonstrated the Nextel(TM)/Kevlar(TM) shield provides superior protection performance compared to an all-aluminum shield alternative. RP Christiansen, EL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN3,HOUSTON,TX 77058, USA. NR 11 TC 22 Z9 24 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 165 EP 172 DI 10.1016/S0734-743X(97)87490-8 PG 8 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800018 ER PT J AU Christiansen, EL Kerr, JH Whitney, JP AF Christiansen, EL Kerr, JH Whitney, JP TI Debris cloud ablation in gas-filled pressure vessels SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY AB The responses of unshielded gas-filled pressure vessels subjected to hypervelocity impact (HVI) are discussed. Similarities and differences between gas-filled pressure vessels and Whipple shields are used to analyze the hypervelocity impact event, specifically the impact of the debris cloud on the rearwall of the vessel. Experimental results demonstrate the effects of important pressure vessel parameters and impact conditions. Damage patterns and mechanisms leading to catastrophic rupture are discussed. Ablation of the debris cloud and pressure vessel wall stress are shown to be important phenomena governing the amount of overall pressure vessel damage. Tests also indicate that ablation is enhanced in the presence of oxygen, and is therefore more extensive in air than in nitrogen under similar test conditions. RP Christiansen, EL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN3,HOUSTON,TX 77058, USA. NR 13 TC 13 Z9 16 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 173 EP 184 DI 10.1016/S0734-743X(97)87491-X PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800019 ER PT J AU Gwynn, DW Horz, F Bernhard, RP See, TH AF Gwynn, DW Horz, F Bernhard, RP See, TH TI The dispersion of molten soda-lime glass projectiles following penetration of thin aluminum membranes SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY ID DEBRIS AB The debris plumes resulting from penetration experiments using soda-lime glass projectiles (3.2 mm diameter; at 6 km/s) and aluminum 1100-0 targets (1.0 and 0.8 mm thick) were intercepted with blued Cu-witness plates some 6, 12 and 49 cm from the target's rear. Scanning Electron Microprobe (SEM) methods and associated Energy Dispersive X-Ray Spectroscopy (EDS) were used to detail the morphology of the witness-plate features and to determine chemically which features were caused by target- or projectile-derived plume components. The projectile suffered complete melting and almost the entire melt volume dispersed into an intricate, three-dimensional network of melt-ribbons and stringers that form a highly regular and reproducible web-like pattern in the central portion of the witness-plate spray. In contrast, the aluminum debris remained solid and was largely concentrated in the peripheral parts of the plume. These experiments also produced prominent circles of closely spaced craters, previously described as ''hole-saw rings''. EDS analysis reveals that such rings are caused by either projectile-derived materials or from fragments dislodged from the target. C1 NASA,SN4,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED MARTIN ENGN & SCI CO,C23,HOUSTON,TX 77058. RP Gwynn, DW (reprint author), LUNAR & PLANETARY INST,3600 BAY AREA BLVD,HOUSTON,TX 77058, USA. NR 10 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 325 EP 336 DI 10.1016/S0734-743X(97)87504-5 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800032 ER PT J AU Horz, F Cintala, MJ Bernhard, RP See, TH AF Horz, F Cintala, MJ Bernhard, RP See, TH TI Evolution of debris plumes as inferred from witness plates SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article; Proceedings Paper CT 1996 Hypervelocity Impact Symposium (HVIS) CY OCT 08-10, 1996 CL FREIBURG, GERMANY AB Photographic overviews and first-order interpretations are presented of witness-plate damage patterns that were produced by 3.2 mm diameter (D-p) soda-lime glass projectiles penetrating targets of aluminum(1110-0) and aluminum(6061-T6), Inconel, lead, and teflon at 6 km/s, and of additional aluminum(1100-0) targets penetrated at 2, 4, 5 and 6.7 km/s. These targets varied systematically in thickness (T) from infinite halfspace to thin films (i.e., 0.1 < D-p/T < 1000). The witness-plate spray patterns from these diverse target materials have remarkably similar characteristics determined in strict response to the absolute target thickness; velocity-dependent effects are minor by comparison. Materials emanating from massive targets (D-p/T < 1) are irregularly distributed on the witness plate, yet they organize into substantially concentric patterns as T decreases, including prominent ''hole-saw-rings'' of craters that are remarkably constant in size, radial dispersion, and azimuthal separation. Components derived from very thin targets organize into radial streaks and projectile debris forms a centrally located cluster of craters. Without exception, projectile debris dominates the central plume portions and target-derived materials reside at the periphery; as target thickness decreases, the spatial separation of these two components becomes increasingly prominent. C1 MARTIN LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. RP Horz, F (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 13 TC 5 Z9 5 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PY 1997 VL 20 IS 1-5 BP 387 EP 398 DI 10.1016/S0734-743X(97)87509-4 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA YJ678 UT WOS:A1997YJ67800037 ER PT J AU Lissenden, CJ Arnold, SM AF Lissenden, CJ Arnold, SM TI Theoretical and experimental considerations in representing macroscale flow/damage surfaces for metal matrix composites SO INTERNATIONAL JOURNAL OF PLASTICITY LA English DT Article DE crack propagation and arrest; elastic-viscoplastic material; fibre-reinforced composite materials; mechanical testing; micromechanics ID MICROMECHANICAL ANALYSIS; INELASTIC DEFORMATION; MODEL AB This report shows how robust, multiaxial, constitutive models for advanced materials can be formulated by using micromechanics to address theoretical and experimental issues. An analytical micromechanical model that includes viscoplastic matrix response, as well as fiber-matrix debonding, is used to predict the multiaxial response of metal matrix composites in terms of macro* flow/damage surfaces at room and elevated temperatures. Macro flow/damage surfaces (i.e. debonding envelopes, matrix threshold surfaces, macro 'yield' surfaces, surfaces of constant inelastic strain rate, and surfaces of constant dissipation rate) are determined for a silicon carbide/titanium composite in three stress spaces. The flow/damage surfaces are shown to have their centers offset from the origin by residual stresses and their shape altered by debonding. The normality condition is shown to be reasonably well satisfied for macro surfaces of constant dissipation rate in the presence of fiber-matrix debonding. These results indicate which types of flow/damage surfaces should be characterized and what loadings must be applied to obtain the most meaningful experimental data for guiding theoretical model development and verification. (C) 1997 Elsevier Science Ltd. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Lissenden, CJ (reprint author), PENN STATE UNIV,UNIVERSITY PK,PA 16802, USA. NR 46 TC 19 Z9 19 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0749-6419 J9 INT J PLASTICITY JI Int. J. Plast. PY 1997 VL 13 IS 4 BP 327 EP 358 DI 10.1016/S0749-6419(97)80003-4 PG 32 WC Engineering, Mechanical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA XL861 UT WOS:A1997XL86100003 ER PT J AU Saravanos, DA Heyliger, PR Hopkins, DA AF Saravanos, DA Heyliger, PR Hopkins, DA TI Layerwise mechanics and finite element for the dynamic analysis of piezoelectric composite plates SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article ID SENSORS ACTUATORS; DESIGN; BEAMS AB Laminate and structural mechanics for the analysis of laminated composite plate structures with piezoelectric actuators and sensors are presented. The theories implement layerwise representations of displacements and electric potential, and can model both the global and local electromechanical response of smart composite laminates. Finite-element formulations are developed for the quasi-static and dynamic analysis of smart composite structures containing piezoelectric layers. Comparisons with an exact solution illustrate the accuracy, robustness and capability of the developed mechanics to capture the global and local response of thin and/or thick laminated piezoelectric plates. Additional correlations and numerical applications demonstrate the unique capabilities of the mechanics in analyzing the static and free vibration response of composite plates with distributed piezoelectric actuators and sensors. Published by Elsevier Science Ltd. RP Saravanos, DA (reprint author), NASA,LEWIS RES CTR,STRUCT MECH BRANCH,2100 BROOKPARK RD,MS 49-8,CLEVELAND,OH 44135, USA. NR 20 TC 216 Z9 223 U1 4 U2 21 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 JAN PY 1997 VL 34 IS 3 BP 359 EP 378 DI 10.1016/S0020-7683(96)00012-1 PG 20 WC Mechanics SC Mechanics GA VX147 UT WOS:A1997VX14700005 ER PT J AU Burlet, KLG Dorney, DJ AF Burlet, KLG Dorney, DJ TI Influence of 3D hot streaks on turbine heat transfer SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID STAGE; REDISTRIBUTION AB Experimental data have shown that combustor temperature non-uniformities can lead to pressure side burning on first-stage turbine rotor blades. Although most modem turbines operate in an environment with significant heat transfer, the majority of hot streak experiments and simulations during the last decade have assumed adiabatic flow. This assumption can cause errors in the prediction of turbine cooling requirements. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed fora 1-1/2 stage-high-pressure turbine geometry operating in subsonic now. Combustor hot streaks and heat transfer effects at the airfoil surfaces were included in-the simulations; The predicted aerodynamic (pressure) data shows close agreement with the available experimental data The predicted heat flux results agree with experimental observations. C1 GMI Engn & Management Inst, Dept Mech Engn, Flint, MI 48504 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Dorney, DJ (reprint author), GMI Engn & Management Inst, Dept Mech Engn, 1700 W 3rd Ave, Flint, MI 48504 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1997 VL 14 IS 3 BP 123 EP 131 PG 9 WC Engineering, Aerospace SC Engineering GA YV189 UT WOS:000071798300002 ER PT J AU Gundy-Burlet, K Dorney, DJ AF Gundy-Burlet, K Dorney, DJ TI Three-dimensional simulations of hot streak clocking in a 1-1/2 stage turbine SO INTERNATIONAL JOURNAL OF TURBO & JET-ENGINES LA English DT Article ID REDISTRIBUTION AB Combustor hot streaks can lead to pressure side "hot spots" on first-stage turbine rotor blades. Previous-numerical studies have confirmed rotor pressure surface temperature increases associated with such combustor hot streaks, and suggest that second-stage turbine stators may be subjected to increased surface temperatures. In this investigation, three dimensional unsteady Navier-Stokes simulations have been performed to verify the benefits of combustor hot streak clocking. The predicted results confirm that if the hot streak is positioned such that it does not impinge upon the first-stage rotor, the pressure surfaces of the rotor and second-stage stator attain high time-averaged temperatures. If the hot streak impinges upon the first-stage stator, the surfaces of downstream blades experience significantly reduced time-averaged temperatures. C1 NASA, Ames Res Ctr, Design Cycle Technol Branch, Moffett Field, CA 94035 USA. GMI Engn & Management Inst, Flint, MI USA. RP Gundy-Burlet, K (reprint author), NASA, Ames Res Ctr, Design Cycle Technol Branch, Moffett Field, CA 94035 USA. NR 19 TC 7 Z9 9 U1 0 U2 0 PU FREUND PUBLISHING HOUSE LTD PI LONDON PA STE 500, CHESHAM HOUSE, 150 REGENT ST, LONDON W1R 5FA, ENGLAND SN 0334-0082 J9 INT J TURBO JET ENG JI Int. J. Turbo. Jet-Engines PY 1997 VL 14 IS 3 BP 133 EP 144 PG 12 WC Engineering, Aerospace SC Engineering GA YV189 UT WOS:000071798300003 ER PT S AU Chun, C Mitchell, CA AF Chun, C Mitchell, CA BE Kozai, T Kubota, C Fujiwara, K Ibaraki, Y Sase, S TI Dynamic control of photosynthetic photon flux for lettuce production in celss SO INTERNATIONAL SYMPOSIUM ON PLANT PRODUCTION IN CLOSED ECOSYSTEMS - AUTOMATION, CULTURE, AND ENVIRONMENT SE ACTA HORTICULTURAE LA English DT Proceedings Paper CT International Symposium on Plant Production in Closed Ecosystems - Automation, Culture, and Environment CY AUG 26-29, 1996 CL NARITA, JAPAN SP Int Soc Hort Sci, Commiss Hort Engn, Japanese Soc Environm Control Biol, Japanese Minist Agr Forestry & Fisheries, Chiba Prefecture, City Narita, Commemorat Assoc Japan World Exposit, Tokyo Elect Power Co, Kansai Elect Power Co, Chubu Power Co, Kyushu Power Co, Shikoku Power Co, Kajima Fdn DE bioregenerative life-support system; computer control; Lactuca sativa L.; PPF AB A new dynamic control of photosynthetic photon flux (PPF) was tested using lettuce canopies growing in the Minitron II plant-growth/canopy gas-exchange system. Canopy photosynthetic rates (Pn) were measured in real time and fedback for further environment control. Pn can be manipulated by changing PPF, which is a good environmental parameter for dynamic control of crop production in a Controlled Ecological Life-Support Systems CELSS. Decision making that combines empirical mathematical models with rule sets developed from recent experimental data was tested. With comparable yield indices and potential for energy savings, dynamic control strategies will contribute greatly to the sustainability of space-deployed CELSS. C1 Purdue Univ, NASA, Specialized Ctr Res & Training Bioregenerat Life, W Lafayette, IN 47907 USA. RP Chun, C (reprint author), Purdue Univ, NASA, Specialized Ctr Res & Training Bioregenerat Life, W Lafayette, IN 47907 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE PI LEUVEN 1 PA PO BOX 500, 3001 LEUVEN 1, BELGIUM SN 0567-7572 BN 90-6605-888-9 J9 ACTA HORTIC PY 1997 IS 440 BP 7 EP 12 PG 6 WC Agronomy; Plant Sciences; Horticulture SC Agriculture; Plant Sciences GA BK30Y UT WOS:000071754800002 ER PT B AU Gomez, SF Hwu, SU AF Gomez, SF Hwu, SU GP ION TI Comparison of space shuttle GPS flight data to geometric theory of diffraction predictions SO ION GPS-97, PT 1 AND 2: PROCEEDINGS OF THE 10TH INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION LA English DT Proceedings Paper CT 10th International Technical Meeting of the Satellite Division of the Institute-of-Navigation CY SEP 16-19, 1997 CL KANSAS CITY CONVENT CTR, KANSAS CITY, MO SP Inst Navigat, Satellite Div HO KANSAS CITY CONVENT CTR AB Multipath is a concern of the International Space Station (ISS) GPS subsystem. The ISS GPS subsystem must provide navigation, attitude, and a time reference. Multipath is the main error source for the attitude determination accuracy. In order to predict the effects of multipath on the ISS, the Uniform Geometric Theory of Diffraction (GTD) technique is being used. This paper compares the results of using that technique to actual data collected on a Space Shuttle flight experiment. Differential carrier phase measurements using a Trimble Advanced Navigation System (TANS) Vector were taken during the 1996 Space Shuttle flight experiment called GPS Attitude and Navigation Experiment (GANE). The GANE used four Micropulse choke ring antennas mounted to a rigid structure which was mounted in the Shuttle payload bay on a HitchHiker platform. A Honeywell inertial reference unit was also mounted to the GANE structure to provide an attitude reference in combination with the Shuttle inertial measurement units and star trackers. The differential carrier phase measurements made during GANE are compared to predicted differential carrier phase measurements using GTD. GTD is a rigorous computational technique that provides a high frequency approximate solution to the electromagnetic fields including incident, reflected, and diffracted fields and their interactions. In general, good agreement was seen between the measured data and the predicted data, but some areas of discrepancy are seen and investigated. C1 NASA, JSC, Greenbelt, MD 20771 USA. RP Gomez, SF (reprint author), NASA, JSC, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU INST NAVIGATION PI WASHINGTON PA 815 15TH ST NW, STE 832, WASHINGTON, DC 20005 USA PY 1997 BP 605 EP 614 PG 10 WC Engineering, Aerospace; Engineering, Marine; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BK75L UT WOS:000073331000060 ER PT B AU Garrison, JL Axelrad, P AF Garrison, JL Axelrad, P GP ION TI Relative navigation in elliptical orbits using an iterative nonlinear filter SO ION GPS-97, PT 1 AND 2: PROCEEDINGS OF THE 10TH INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION LA English DT Proceedings Paper CT 10th International Technical Meeting of the Satellite Division of the Institute-of-Navigation CY SEP 16-19, 1997 CL KANSAS CITY CONVENT CTR, KANSAS CITY, MO SP Inst Navigat, Satellite Div HO KANSAS CITY CONVENT CTR AB The two step filter is applied to process intersatellite radar measurements to determine the motion of one satellite relative to another in close elliptical orbits. This filter breaks a nonlinear estimation problem into two state vectors. The "first step" state is chosen so as to have a linear measurement equation. This is nonlinearly related to the "second step" state which describes the dynamics. Two different forms are used. In one, the first step state is the second step state vector augmented by the measurement equation. In the other, the first step and second step state vectors are of equal dimension. The two step filter is compared against an iterated extended Kalman filter and a Kalman filter using a change of variables. Analytical differences between the two step estimator and these conventional filters are highlighted. Special concerns for initializing the first step state covariance matrix and handling the possibility of numerically rank deficient covariance matrices are addressed. Numerical simulations are performed which show that the Two Step estimator produces a lower estimation bias under two circumstances; large apriori initial error; and small dimension observation vectors which require a longer are of measurements to generate observability of the state. C1 NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Hampton, VA 23665 USA. RP Garrison, JL (reprint author), NASA, Langley Res Ctr, Spacecraft & Sensors Branch, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST NAVIGATION PI WASHINGTON PA 815 15TH ST NW, STE 832, WASHINGTON, DC 20005 USA PY 1997 BP 745 EP 754 PG 10 WC Engineering, Aerospace; Engineering, Marine; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BK75L UT WOS:000073331000074 ER PT B AU Neilan, RE Zumberge, JF Beutler, G Kouba, J AF Neilan, RE Zumberge, JF Beutler, G Kouba, J GP ION TI The international GPS service: A global resource for GPS applications and research SO ION GPS-97, PT 1 AND 2: PROCEEDINGS OF THE 10TH INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION LA English DT Proceedings Paper CT 10th International Technical Meeting of the Satellite Division of the Institute-of-Navigation CY SEP 16-19, 1997 CL KANSAS CITY CONVENT CTR, KANSAS CITY, MO SP Inst Navigat, Satellite Div HO KANSAS CITY CONVENT CTR AB Since June, 1992, the International GPS Service has been coordinating a global civilian GPS infrastructure in order to support numerous GPS applications and research activities. A key aspect of the IGS is the reliability and quality of the analysis products that have been made available over the past five years through the IGS Analysis Centers and the Analysis Center Coordinator. On A daily basis these IGS centers produce precise satellite orbits, Earth orientation parameters, satellite and receiver clocks, atmospheric and ionospheric data. Recent improvements in the IGS include production of predicted (50 cm rms) and rapid orbit products (10 cm rms), generation of an official IGS Earth orientation parameters (eop) series, combined site-specific tropospheric estimates for determining precipitable water vapor, and ionospheric delay estimates from the IGS network. A key project of the IGS is the Densification Project of the International Terrestrial Reference Frame (ITRF) through GPS. On a regular basis station coordinates and velocities of global and regional stations are produced in this precise, truly global reference frame. Additionally, the IGS is now considering its role in supporting upcoming Low Earth Orbiting missions; its potential contribution to long term monitoring of sea level heights and altimeter calibration through the GPS; and extending the IGS infrastructure to support observations and analysis of GLONASS system. C1 CALTECH, Jet Prop Lab, IGS Cent Bur, Pasadena, CA 91125 USA. RP Neilan, RE (reprint author), CALTECH, Jet Prop Lab, IGS Cent Bur, Pasadena, CA 91125 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU INST NAVIGATION PI WASHINGTON PA 815 15TH ST NW, STE 832, WASHINGTON, DC 20005 USA PY 1997 BP 883 EP 889 PG 7 WC Engineering, Aerospace; Engineering, Marine; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BK75L UT WOS:000073331000089 ER PT B AU Hawley, C Panda, P Holm, J AF Hawley, C Panda, P Holm, J GP IEEE TI Meeting the challenge of electronic communication SO IPCC 97 PROCEEDINGS - 1997 IEEE INTERNATIONAL PROFESSIONAL COMMUNICATION CONFERENCE: CROSSROADS IN COMMUNICATION LA English DT Proceedings Paper CT 1997 IEEE International Professional Communication Conference (IPCC 97) on Crossroads in Communication CY OCT 22-25, 1997 CL SALT LAKE CITY, UT SP IEEE Profess Commun Soc AB The Jet Propulsion Laboratory (JPL), California Institute of Technology, is challenged with not only providing an environment where engineers and scientists can exchange information quickly and accurately, but also providing the public with the fruits of its exploration in a way that is both interesting and understandable to all age groups and professional arenas. Web technology has given us the means to meet this challenge. A myriad of tools and technologies are used daily to solve communication problems from simple memo distribution to highly complex Web sites instantly delivering custom data around the world. RP Hawley, C (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4184-8 PY 1997 BP 145 EP 148 PG 4 WC Computer Science, Information Systems; Communication SC Computer Science; Communication GA BJ87E UT WOS:A1997BJ87E00018 ER PT B AU Vaisnys, A Chen, EY AF Vaisnys, A Chen, EY GP IEEE TI Digital audio applications to short wave broadcasting SO ISIE '97 - PROCEEDINGS OF THE IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, VOLS 1-3 LA English DT Proceedings Paper CT IEEE International Symposium on Industrial Electronics CY JUL 07-11, 1997 CL UNIV MINHO, GUIMARAES, PORTUGAL SP IEEE Ind Electr Soc, Univ Minho, Soc Ind & Control Engn, Japan, IEEE Portugal Sect, IEEE Ind Electr Portugal Chapter, IEEE Neural Network Council, Portuguese Assoc Automat Control, IEEE Reg 8 HO UNIV MINHO AB Digital audio is becoming prevalent not only in consumer electronics, but also in different broadcasting media. Terrestrial analog audio broadcasting in the AM and FM bands will be eventually be replaced by digital systems. In the United States, developments include in band digital systems for the FM and AM bands, while in Europe and elsewhere, the Eureka 147 system is undergoing large scale trials. Digital audio broadcasting via satellite is a reality in conjunction with direct to home TV broadcasting. Satellite delivery of audio to mobile receivers is under development. Worldspace has proposed a system of moderate rate digital audio delivery via satellite internationally via a three satellite system, while two organizations have been granted licenses to provide CD quality satellite audio domestically in the U.S. The one broadcasting service which has indicated an interest in snitching to digital, but ir somewhat behind in system development is short wave broadcasting. The minimization of data rate is very important in broadcasting because of bandwidth and power constraints. Audio compression is therefore used to reduce the data rate required to transmit and reproduce the audio at the receiver. The data rate that is needed depends on the audio bandwidth that is to be maintained, whether it is monaural or stereo, and the distortion level that can be tolerated by the audience. A great deal of effort has been expended to bring down the data rate needed to reproduce CD quality audio, on the high end of the audio compression performance scale, and on speech compression for telephony, on the low end of the scale. Less work has been done in the medium bandwidth speech and music area, which is most appropriate for short wave broadcasting. The bandwidth of a short wave channel is 10 kHz. The narrow bandwidth and the very difficult propagation characteristics of the NF bands will severely limit the data rate that can be transmitted. It will take a very efficient compression scheme to achieve the desired voice and music quality. In addition, attention must be paid to the interaction of the receiver and audio decoder in minimizing undesirable audio artifacts when the received signal approaches threshold. This paper describes the unique requirements of audio compression systems suitable for I-IF broadcasting from the perspective of the overall short wave broadcasting system design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vaisnys, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-3936-3 PY 1997 BP SS33 EP SS36 PG 4 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BK48L UT WOS:000072310300014 ER PT B AU Erlebacher, G Hussaini, MY Jackson, TL AF Erlebacher, G Hussaini, MY Jackson, TL BE Champion, M Deshaies, B TI Numerical simulations of shock-turbulence interactions SO IUTAM SYMPOSIUM ON COMBUSTION IN SUPERSONIC FLOWS SE FLUID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT IUTAM Symposium on Combustion in Supersonic Flows CY OCT 02-06, 1995 CL POITIERS, FRANCE SP Int Union Theoret & Appl Mech, Aerospatiale, SNECMA, CNRS, French Minist Res, French Minist Def, City Poitiers, Conseil Gen Vienne, Reg Poitous Charentes AB The interaction of turbulence with a shock wave is investigated by a direct two-dimensional numerical simulation of the compressible Euler equations using a shock-fitted approach. The numerical method involves a compact 6(th) order discretization scheme for the spatial derivatives, while time advancement is based on a low-storage 5 stage, 4(th) order accurate Runga-Kutta scheme. For small amplitudes, the numerical calculations are compared to linear theory for validation. Comparisons include the interaction of a single oblique vorticity wave, and turbulence viewed as a collection of single vorticity waves. Nonlinear effects are analyzed by presenting one-dimensional power spectra for the vorticity and divergence. The interaction of a single vortex and a shock wave is also investigated and compared to linear results. Results are presented for various vortex strengths and at various Mach numbers. RP Erlebacher, G (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4313-1 J9 FLUID MEC A PY 1997 VL 39 BP 317 EP 324 PG 4 WC Mechanics SC Mechanics GA BH65M UT WOS:A1997BH65M00026 ER PT J AU Connell, JW Smith, JG Hergenrother, PM AF Connell, JW Smith, JG Hergenrother, PM TI Chemistry and adhesive properties of phenylethynyl-terminated phenylquinoxaline oligomers SO JOURNAL OF ADHESION LA English DT Article DE adhesives; phenylethynyl termination; phenylquinoxalines; reactive thermoplastics; high temperature polymers; mechanical properties; titanium; processability; solvent resistance ID ETHYNYL GROUPS; ANHYDRIDES; POLYIMIDES AB As part of a program to develop high performance/high temperature structural resins for potential aeronautical applications, phenylethynyl-terminated phenylquinoxaline oligomers were prepared, characterized, thermally cured and the cured resins were evaluated as adhesives. The phenylquinoxaline oligomers were prepared by conventional and aromatic nucleophilic displacement routes and chain terminated with mono or di(phenylethynyl) groups. The oligomers were melt pressed into thin films, compression molded into tensile and compact tension specimens, and fabricated into titanium-to-titanium single lap shear adhesive specimens. The oligomers were generally compression molded for 1 hr at 350 degrees C under pressures ranging from 0.10 to 1.4 MPa. The phenylquinoxaline oligomer prepared via aromatic nucleophilic displacement exhibited better processability and higher tensile shear strengths than those of the oligomers prepared via the conventional synthetic route. The synthesis, physical and mechanical properties of these oligomers and their cured polymers are presented. C1 NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. NR 32 TC 7 Z9 8 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0021-8464 J9 J ADHESION JI J. Adhes. PY 1997 VL 60 IS 1-4 BP 15 EP 26 DI 10.1080/00218469708014406 PG 12 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA YY951 UT WOS:000072204300002 ER PT J AU Cano, RJ Jensen, BJ AF Cano, RJ Jensen, BJ TI Effect of molecular weight on processing and adhesive properties of the phenylethynyl-terminated polyimide LARC (TM)-PETI-5 SO JOURNAL OF ADHESION LA English DT Article DE adhesives; polyimides; phenylethynyl; processing; molecular weight AB Three different molecular weight versions of the phenylethynyl-terminated polyimide LARC(TM)-PETI-5 were synthesized. The materials synthesized had theoretical number average molecular weights of 2500, 5000,and 10000 g/mol. Differential Scanning Calorimetry (DSC) was performed on the dry powder form of these materials to establish cure conditions which result in high glass transition temperatures. Lap shear specimens were prepared from adhesive tape made from each material and with the thermal cure conditions determined from the DSC data. The tensile shear data established which processing conditions provided the best adhesive strengths. Titanium tensile shear strengths as high as 52.6 MPa (7630 psi) al RT and 35.2 MPa (5100 psi) at 177 degrees C were determined. Processing temperatures as low as 316 degrees C and pressures as low as 0.17 MPa (25 psi) resulted in good adhesive properties. The tensile shear properties of these materials were unaffected by hydraulic fluid. The molecular weight of LARC(TM)-PETI-5 has an important effect on the bonding pressures required to obtain good tensile shear strengths. The effect of molecular weight on the utility of PETI-5 to be used as a primer to maintain surface quality for bonding was also investigated. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cano, RJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 TC 43 Z9 43 U1 0 U2 6 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0021-8464 J9 J ADHESION JI J. Adhes. PY 1997 VL 60 IS 1-4 BP 113 EP 123 DI 10.1080/00218469708014413 PG 11 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA YY951 UT WOS:000072204300009 ER PT J AU Patnaik, SN Lavelle, TM Hopkins, DA AF Patnaik, SN Lavelle, TM Hopkins, DA TI Cascade optimization strategy for aircraft and air-breathing propulsion system concepts SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 6th Aerospace Sciences Meeting CY SEP 04-06, 1996 CL BELLEVUE, WA SP AIAA C1 NASA,LEWIS RES CTR,AEROPROP ANAL OFF,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,STRUCT & ACOUST BRANCH,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,COMPUTAT SCI BRANCH,CLEVELAND,OH 44135. RP Patnaik, SN (reprint author), OHIO AEROSP INST,STRUCT & ACOUST BRANCH,CLEVELAND,OH 44142, USA. NR 6 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 JAN-FEB PY 1997 VL 34 IS 1 BP 136 EP 139 DI 10.2514/2.2148 PG 4 WC Engineering, Aerospace SC Engineering GA WP100 UT WOS:A1997WP10000021 ER PT J AU Cooper, D Pellis, NR AF Cooper, D Pellis, NR TI Suppressed lectin-induced proliferation of T lymphocytes in simulated microgravity is restored by direct activation of PKC. SO JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY LA English DT Meeting Abstract C1 UNIV TEXAS,GRAD SCH BIOMED SCI,HOUSTON,TX. UNIV SPACE RES ASSOC,HOUSTON,TX. NASA,LYNDON B JOHNSON SPACE CTR,BIOTECHNOL PROGRAM,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MOSBY-YEAR BOOK INC PI ST LOUIS PA 11830 WESTLINE INDUSTRIAL DR, ST LOUIS, MO 63146-3318 SN 0091-6749 J9 J ALLERGY CLIN IMMUN JI J. Allergy Clin. Immunol. PD JAN PY 1997 VL 99 IS 1 SU S BP 1277 EP 1277 PN 2 PG 1 WC Allergy; Immunology SC Allergy; Immunology GA WH142 UT WOS:A1997WH14201274 ER PT J AU Mishra, S Randolph, T Pierson, D Burge, H AF Mishra, S Randolph, T Pierson, D Burge, H TI Particle size characteristics of airborne cultural fungi. SO JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY LA English DT Meeting Abstract C1 HARVARD UNIV,SCH PUBL HLTH,BOSTON,MA 02115. NASA,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MOSBY-YEAR BOOK INC PI ST LOUIS PA 11830 WESTLINE INDUSTRIAL DR, ST LOUIS, MO 63146-3318 SN 0091-6749 J9 J ALLERGY CLIN IMMUN JI J. Allergy Clin. Immunol. PD JAN PY 1997 VL 99 IS 1 SU S BP 1588 EP 1588 PN 2 PG 1 WC Allergy; Immunology SC Allergy; Immunology GA WH142 UT WOS:A1997WH14201584 ER PT J AU Tennyson, JM AF Tennyson, JM TI Seafoods SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article RP Tennyson, JM (reprint author), NATL MARINE FISHERIES SERV,NATL SEAFOOD INSPECT LAB,3209 FREDERIC ST,PO DRAWER 1207,PASCAGOULA,MS 39568, USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD JAN-FEB PY 1997 VL 80 IS 1 BP 158 EP 162 PG 5 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA WE486 UT WOS:A1997WE48600046 ER PT J AU Frank, J Cheeseman, P Stutz, J AF Frank, J Cheeseman, P Stutz, J TI When gravity fails: Local search topology SO JOURNAL OF ARTIFICIAL INTELLIGENCE RESEARCH LA English DT Article AB Local search algorithms for combinatorial search problems frequently encounter a sequence of states in which it is impossible to improve the value of the objective function; moves through these regions, called plateau moves, dominate the time spent in local search. We analyze and characterize plateaus for three different classes of randomly generated Boolean Satisfiability problems. We identify several interesting features of plateaus that impact the performance of local search algorithms. We show that local minima tend to be small but occasionally may be very large. We also show that local minima can be escaped without unsatisfying a large number of clauses, but that systematically searching for an escape route may be computationally expensive if the local minimum is large. We show that plateaus with exits, called benches, tend to be much larger than minima, and that some benches have very few exit states which local search can use to escape. We show that the solutions (i.e., global minima) of randomly generated problem instances form clusters, which behave similarly to local minima. We revisit several enhancements of local search algorithms and explain their performance in light of our results. Finally we discuss strategies for creating the next generation of local search algorithms. C1 NASA, Ames Res Ctr, Caelum Res Corp, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Frank, J (reprint author), NASA, Ames Res Ctr, Caelum Res Corp, Mail Stop N269-1, Moffett Field, CA 94035 USA. EM FRANK@TIZIANO.ARC.NASA.GOV; CHEESEM@PTOLEMY.ARC.NASA.GOV; STUTZ@PTOLEMY.ARC.NASA.GOV NR 16 TC 43 Z9 43 U1 1 U2 1 PU AI ACCESS FOUNDATION PI MARINA DEL REY PA USC INFORMATION SCIENCES INST, 4676 ADMIRALITY WAY, MARINA DEL REY, CA 90292-6695 USA SN 1076-9757 J9 J ARTIF INTELL RES JI J. Artif. Intell. Res. PY 1997 VL 7 BP 249 EP 281 PG 33 WC Computer Science, Artificial Intelligence SC Computer Science GA YP717 UT WOS:000071307000001 ER PT J AU Hines, CO Mayr, HG Reddy, CA AF Hines, CO Mayr, HG Reddy, CA TI On the analysis of geophysical data for an unknown constant, exemplified by the problem of the O+-O collision cross-section SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID AERONOMICAL MEASUREMENTS AB Geophysical data that are employed to determine some constant parameter are often subjected to a least-squares method of analysis. Uncritical use of this method has been found to be inappropriate. An alternative method, based on the analysis of the errors that must be associated with any chosen method of data reduction, is recommended in its place. The relevant principles are exemplified by the currently active problem of the O+-O collision cross-section as determined from aeronomic measurements. These principles lead to specific recommendations for future data analysis in this area. Copyright (C) 1996 Elsevier Science Ltd. RP Hines, CO (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 6 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD JAN PY 1997 VL 59 IS 2 BP 181 EP 189 DI 10.1016/1364-6826(95)00197-2 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA WL048 UT WOS:A1997WL04800004 ER PT J AU Stieglitz, M Rind, D Famiglietti, J Rosenzweig, C AF Stieglitz, M Rind, D Famiglietti, J Rosenzweig, C TI An efficient approach to modeling the topographic control of surface hydrology for regional and global climate modeling SO JOURNAL OF CLIMATE LA English DT Article ID SOIL-MOISTURE; WATER; RUNOFF; RIVER; SCALE; DROUGHT; FOREST; FLOW; EVAPOTRANSPIRATION; SIMILARITY AB The current generation of land-surface models used in GCMs view the soil column as the fundamental hydrologic unit. While this may be effective in simulating such processes as the evolution of ground temperatures and the growth/ablation of a snowpack at the soil plot scale, it effectively ignores the role topography plays in the development of soil moisture heterogeneity and the subsequent impacts of this soil moisture heterogeneity on watershed evapotranspiration and the partitioning of surface fluxes. This view also ignores the role topography plays in the timing of discharge and the partitioning of discharge into surface runoff and baseflow. In this paper an approach to land-surface modeling is presented that allows us to view the watershed as the fundamental hydrologic unit. The analytic form of TOPMODEL equations are incorporated into the soil column framework and the resulting model is used to predict the saturated fraction of the watershed and baseflow in a consistent fashion. Soil moisture heterogeneity represented by saturated lowlands subsequently impacts the partitioning of surface fluxes, including evapotranspiration and runoff. The approach is computationally efficient, allows for a greatly improved simulation of the hydrologic cycle, and is easily coupled into the existing framework of the current generation of single column land-surface models. Because this approach uses the statistics of the topography rather than the details of the topography, it is compatible with the large spatial scales of today's regional and global climate models. Five years of meteorological and hydrological data from the Sleepers River watershed located in the northeastern United States where winter snow cover is significant were used to drive the new model. Site validation data were sufficient to evaluate model performance with regard to various aspects of the watershed water balance, including snowpack growth/ablation, the spring snowmelt hydrograph, storm hydrographs, and the seasonal development of watershed evapotranspiration and soil moisture. C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. COLUMBIA UNIV,DEPT GEOL SCI,NEW YORK,NY. UNIV TEXAS,DEPT GEOL SCI,AUSTIN,TX. NR 66 TC 128 Z9 136 U1 4 U2 16 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JAN PY 1997 VL 10 IS 1 BP 118 EP 137 DI 10.1175/1520-0442(1997)010<0118:AEATMT>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ834 UT WOS:A1997WJ83400009 ER PT J AU Kincaid, RK Laba, KE Padula, SL AF Kincaid, RK Laba, KE Padula, SL TI Quelling cabin noise in turboprop aircraft via active control SO JOURNAL OF COMBINATORIAL OPTIMIZATION LA English DT Article DE tabu search; optimal location selection AB Cabin noise in turboprop aircraft causes passenger discomfort, airframe fatigue, and employee scheduling constraints due to OSHA standards for exposure to high levels of noise. The noise levels in the cabins of turboprop aircraft are typically 10 to 30 decibels louder than commercial jet noise levels. However, unlike jet noise the turboprop noise spectrum is dominated by a few low frequency tones. Active structural acoustic control is a method in which the control inputs (used to reduce interior noise) are applied directly to a vibrating structural acoustic system. The control concept modeled in this work is the application of in-plane force inputs to piezoceramic patches bonded to the wall of a vibrating cylinder. The goal is to determine the force inputs and locations for the piezoceramic actuators so that (1) the interior noise is effectively damped; (2) the level of vibration of the cylinder shell is not increased; and (3) the power requirements needed to drive the actuators are not excessive. Computational experiments for data taken from a computer generated model and from a laboratory test article at NASA Langley Research Center are provided. C1 Coll William & Mary, Dept Math, Williamsburg, VA 23185 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Kincaid, RK (reprint author), Coll William & Mary, Dept Math, Williamsburg, VA 23185 USA. NR 20 TC 7 Z9 7 U1 2 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1382-6905 J9 J COMB OPTIM JI J. Comb. Optim. PY 1997 VL 1 IS 3 BP 229 EP 250 DI 10.1023/A:1009724325820 PG 22 WC Computer Science, Interdisciplinary Applications; Mathematics, Applied SC Computer Science; Mathematics GA 115UE UT WOS:000075683200003 ER PT J AU Bowles, KJ Madhukar, M Papadopoulos, DS Inghram, L McCorkle, L AF Bowles, KJ Madhukar, M Papadopoulos, DS Inghram, L McCorkle, L TI The effects of fiber surface modification and thermal aging on composite toughness and its measurement SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID THERMOOXIDATIVE STABILITY; PMR-15 AB A detailed experimental study was conducted to establish the structure-property relationships between elevated temperature aging and (I) fiber-matrix bonding, (2) Mode II interlaminar fracture toughness, and (3) failure modes of carbon fiber/PMR-15 composites. The fiber-matrix adhesion was varied by using carbon fibers with different surface treatments. Short beam shear tests were used to quantify the interfacial shear strength afforded by the use of the different fiber surface treatments. The results of the short beam shear tests definitely showed that, for aging times up to 1000 hr, the aging process caused no observable changes in the bulk of the three composite materials that would degrade the shear properties of the material. Comparisons between the interlaminar shear strength (ILSS) measured by the short beam shear tests and the G(IIc) test results, as measured by the ENF test, indicated that the differences in the surface treatments significantly affected the fracture properties while the effect of the aging process was probably limited to changes at the starter crack tip. The fracture properties changed due to a shift in the fracture from an interfacial failure to a failure within the matrix when the fiber was changed from AU-4 to AS-4 or AS-4G. There appears to be an effect of the fiber/matrix bonding on the thermo-oxidative stability of the composites that were tested. The low bonding afforded by the AU-4 fiber resulted in weight losses about twice those experienced by the AS-4 reinforced composites, the ones with the best TOS. The results are in agreement with those of previous work completed by the authors. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. GILCREST CORP,CLEVELAND,OH 44135. RP Bowles, KJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. RI Madhukar, Madhu/P-4365-2015 NR 17 TC 18 Z9 19 U1 0 U2 3 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1997 VL 31 IS 6 BP 552 EP 579 PG 28 WC Materials Science, Composites SC Materials Science GA WU721 UT WOS:A1997WU72100002 ER PT J AU Madhukar, MS Bowles, KJ Papadopoulos, DS AF Madhukar, MS Bowles, KJ Papadopoulos, DS TI Thermo-oxidative stability and fiber surface modification effects on the inplane shear properties of graphite/PMR-15 composites SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID BISMALEIMIDE PMR-15 COMPOSITES; CARBON-FIBERS; GENERATION; STRAINS AB Experiments were conducted to study the effects of thermo-oxidative stability (weight loss) and fiber surface modification on the inplane shear properties of graphite/PMR-15 unidirectional composites. The isothermal aging was conducted at 316 degrees C and up to 1000 hours of aging times. The role of fiber surface treatment on the composite degradation during the thermo-oxidative aging was investigated by using A-4 graphite fibers having three different surface modifications, namely untreated (AU-4), surface treated (AS-4), and surface treated and sized with epoxy-compatible sizing (AS-4G). Weight loss of matrix, fibers, and composites was determined during the aging. The effect of thermal aging was seen in all the fiber samples in terms of their weight loss and reduction in fiber diameter. Calculated values of weight loss fluxes for different surfaces of rectangular unidirectional composite plates showed that the largest weight loss occurs at those cut surfaces where fibers are perpendicular to the surface. Consequently, the largest amount of damage was also noted on these cut surfaces. Optical observation of neat matrix and composites plates subjected to the different aging times revealed that the degradation (such as matrix microcracking, void growth, etc.) occurred within a thin surface layer near specimen edges. The inplane shear modulus of the composites was unaffected by the fiber surface treatment and the thermal aging. The shear strength of the composites having the untreated fibers was the lowest and it decreased with aging. Fracture surface examination of the composites having untreated fibers suggests that the weak interface allows the oxidation reaction to proceed along the interface and thus expose the inner material to further oxidation. The results indicate that fiber-matrix interface affects the composite degradation process during its thermal aging and that the weak interface accelerates the composite degradation. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP Madhukar, MS (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. RI Madhukar, Madhu/P-4365-2015 NR 18 TC 14 Z9 15 U1 0 U2 4 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1997 VL 31 IS 6 BP 596 EP 618 PG 23 WC Materials Science, Composites SC Materials Science GA WU721 UT WOS:A1997WU72100004 ER PT J AU Gates, TS Veazie, DR Brinson, LC AF Gates, TS Veazie, DR Brinson, LC TI Creep and physical aging in a polymeric composite: Comparison of tension and compression SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article ID MATRIX COMPOSITES; BEHAVIOR AB To help address the lack of engineering data on the time-dependent behavior of advanced polymeric composites, a combined experimental and analytical research program was initiated to investigate the similarities and differences of the effects of physical aging on creep compliance of IM7/K3B composite loaded in tension and compression. Recently developed novel experimental apparatus and methods were employed to test two matrix dominated loading modes, shear and transverse, for two load cases, tension and compression. The tests, run over a range of sub-glass transition temperatures, provided material constants, material master curves and aging related parameters. Assessment of these new results indicated that although trends in the data with respect to aging time and aging temperature are similar, differences exist due to load direction and mode. An analytical model proposed previously by the authors for tension loading was used for predicting long-term tension and compression behavior using short-term data as input. These new studies indicated that the model worked equally as well for the tension or compression loaded cases. Comparison of the loading modes indicated that the predictive model provided more accurate long-term predictions for the shear mode as compared to the transverse mode. Parametric studies showed the usefulness of the predictive model as a tool for investigating long-term performance and compliance acceleration due to temperature. C1 NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. Clark Atlanta Univ, Atlanta, GA 30314 USA. Northwestern Univ, Evanston, IL 60208 USA. RP Gates, TS (reprint author), NASA, Langley Res Ctr, Div Mat, Mail Code 188E, Hampton, VA 23681 USA. RI Brinson, L. Catherine/B-6678-2009; Brinson, L Catherine/B-1315-2013 OI Brinson, L Catherine/0000-0003-2551-1563 NR 23 TC 26 Z9 26 U1 1 U2 5 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PY 1997 VL 31 IS 24 BP 2478 EP 2505 PG 28 WC Materials Science, Composites SC Materials Science GA YT486 UT WOS:000071610900004 ER PT J AU Harris, CE Coats, TW Allen, DH Lo, DC AF Harris, CE Coats, TW Allen, DH Lo, DC TI A progressive damage model and analysis methodology for predicting the residual strength of composite laminates SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE composites; graphite/epoxy; damage; matrix cracks; delamination; internal state variables ID THERMOMECHANICAL CONSTITUTIVE THEORY; ELASTIC COMPOSITES; DISTRIBUTED DAMAGE; CRACKING AB The durability and damage tolerance of laminated composites are critical design considerations for airframe composite structures. Therefore, the ability to model damage initiation and growth and predict the life of laminated composites is necessary to achieve efficient and economical structural designs. The purpose of the research presented in this paper is to experimentally verify the application of the damage model developed by the authors to predict progressive damage development in a toughened material system. Damage growth, stiffness degradation, and residual strength were experimentally determined for cross-ply and quasi-isotropic IM7/5260 graphite/bismaleimide laminates due to monotonic and tension-tension fatigue. The damage model, which has been implemented into a finite element code, was used to predict the stiffness loss and residual strength of unnotched and notched laminates. The model predictions were in good agreement to experimental results for several different fatigue loading histories and several different laminate stacking sequences. C1 TEXAS A&M UNIV,DEPT AEROSP ENGN,COLLEGE STN,TX 77840. RP Harris, CE (reprint author), NASA,LANGLEY RES CTR,DIV MAT,MAIL STOP 188M,HAMPTON,VA 23681, USA. NR 21 TC 19 Z9 23 U1 1 U2 4 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 JAN PY 1997 VL 19 IS 1 BP 3 EP 9 PG 7 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA WE664 UT WOS:A1997WE66400001 ER PT J AU Frazier, DO Hung, RJ Paley, MS Penn, BG Long, YT AF Frazier, DO Hung, RJ Paley, MS Penn, BG Long, YT TI Buoyancy-driven heat transfer during application of a thermal gradient for the study of vapor deposition at low pressure using an ideal gas SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID PHTHALOCYANINE THIN-FILMS; ANGLE SPECTROSCOPIC ELLIPSOMETRY; COPPER PHTHALOCYANINE; SLOSH WAVES; MICROGRAVITY ENVIRONMENT; MOMENT FLUCTUATIONS; OPTICAL-PROPERTIES; SINGLE-CRYSTALS; VISCOUS STRESS; SLEW MOTION AB A mathematical model has been developed to determine heat transfer during vapor deposition of source materials under a variety of orientations relative to gravitational accelerations. The model demonstrates that convection can occur at total pressures as low as 10(-2) mm Hg. Through numerical computation, using physical material parameters of air, a series of time steps demonstrates the development of flow and temperature profiles during the course of vapor deposition. These computations show that in unit gravity vapor deposition occurs by transport through a fairly complicated circulating flow pattern when applying heat to the bottom of the vessel with parallel orientation with respect to the gravity vector. The model material parameters for air predict the effect of kinematic viscosity to be of the same order as thermal diffusivity, which is the case for Prandtl number similar to 1 fluids. Qualitative agreement between experiment and the model indicates that 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-1-ol (DAMNA) at these pressures indeed approximates an ideal gas at the experiment temperatures, and may validate the use of air physical constants. It is apparent that complicated nonuniform temperature distribution in the vapor could dramatically affect the homogeneity, orientation, and quality of deposited films. The experimental test is a qualitative comparison of film thickness using ultraviolet-visible spectroscopy on films generated in appropriately oriented vapor deposition cells. In the case where heating of the reaction vessel occurs from the top, deposition of vapor does not normally occur by convection due to a stable stratified medium. When vapor deposition occurs in vessels heated at the bottom, but oriented relative to the gravity vector between these two extremes, horizontal thermal gradients induce a complex flow pattern. In the plane parallel to the tilt axis, the flow pattern is symmetrical and opposite in direction from that where the vessel is positioned vertically. The ground-based experiments are sufficient preliminary tests of theory and should be of significant interest regarding vapor deposited films in microgravity. C1 UNIV ALABAMA,DEPT MECH & AEROSP ENGN,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. RP Frazier, DO (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 45 TC 9 Z9 9 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 JAN PY 1997 VL 171 IS 1-2 BP 288 EP 302 DI 10.1016/S0022-0248(96)00500-3 PG 15 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA WE271 UT WOS:A1997WE27100035 ER PT J AU Moursi, AM Najafi, M Globus, RK Damsky, CH AF Moursi, AM Najafi, M Globus, RK Damsky, CH TI Integrin-fibronectin interactions are critical for osteogenesis and osteoblast differentiation. SO JOURNAL OF DENTAL RESEARCH LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT STOMATOL,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 1 U2 1 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PY 1997 VL 76 SI SI BP 2261 EP 2261 PG 1 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA WB680 UT WOS:A1997WB68002255 ER PT J AU Xu, KM Noor, AK Burton, WS AF Xu, KM Noor, AK Burton, WS TI 3D solutions for free vibration of initially stressed thermoelectroelastic multilayered cylinders SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID 3-DIMENSIONAL SOLUTIONS; SHELLS; ACTUATORS; PANELS AB Analytic three-dimensional solutions are presented for the free vibration problems of initially stressed hybrid multilayered composite circular cylindrical shells. The shells consist of a combination of fiber-reinforced cross-ply and piezothermoelastic layers. The initial stresses are generated by either a temperature change and/or an electric field. Sensitivity coefficients are also evaluated and used to study the sensitivity of the vibrational response to variations in the different mechanical, thermal and piezoelectric material properties of the shells. Both the temperature change and the radial component of the electric field are assumed to have uniform distribution in each layer of the shells. A linear constitutive model is used, and the material properties are assumed to be independent of both the temperature and the electric field. The thermoelectroelastic response of the shell is subjected to time-varying displacements, strains, and stresses, and the free vibration response is studied. A mixed formulation is used with the fundamental unknowns consisting of the increments of the three transverse stress components and the three displacement components of the shell. Each of the fundamental unknowns is expressed in terms of a double Fourier series in the axial and circumferential surface coordinates. A state space approach is used to generate the vibrational response and to evaluate the sensitivity coefficients. A sublayer method is used for evaluating vibration frequencies and their sensitivity coefficients. Numerical results are presented showing the effects of variation in the shell thickness, and the location of the piezothermoelastic layers on the vibration frequencies and their sensitivity coefficients. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR ADV COMPUTAT TECHNOL,HAMPTON,VA. RP Xu, KM (reprint author), NASA,LANGLEY RES CTR,CTR ADV COMPUTAT TECHNOL,MAIL STOP 369,HAMPTON,VA 23681, USA. NR 21 TC 9 Z9 11 U1 1 U2 1 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD JAN PY 1997 VL 123 IS 1 BP 45 EP 51 DI 10.1061/(ASCE)0733-9399(1997)123:1(45) PG 7 WC Engineering, Mechanical SC Engineering GA VY990 UT WOS:A1997VY99000006 ER PT J AU Sabaka, TJ Langel, RA Baldwin, RT Conrad, JA AF Sabaka, TJ Langel, RA Baldwin, RT Conrad, JA TI The geomagnetic field 1900-1995, including the large-scale field from magnetospheric sources, and the NASA candidate models for the 1995 revision of the IGRF SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article ID EARTHS MAGNETIC-FIELD; SIMULTANEOUS STOCHASTIC INVERSION; SECULAR VARIATION; MAIN FIELD; FLUCTUATIONS; ROTATION; SPECTRUM; TIME; CORE AB This paper reports on a continuous representation of the main geomagnetic field of degree 13 for the 1990-1995 time period, including a degree 1 representation of the field of external origin, designated GSFC(S95). The model employs a cubic B-spline basis with equi-spaced knots for the temporal variation in the secular variation of the internal field. Hence, the temporal variation of the spherical harmonic coefficients is represented by integrals of cubic B-splines. In the derivation, a suite of different forms is utilized for representation of the external field: (1) GSFC(S95-a), in which the external terms are proportional to the annual averages of the aa index, (2) GSFC(S95-s), in which the external terms are represented by unconstrained cubic B-splines, (3) GSFC(S95-sc), in which the cubic B-spline representation of the external field is constrained to be near the GSFC(S95-a) model for years prior to about 1940, and, (4) GSFC(S95-nx), in which there is no external field representation. The NASA candidate models for the 1995 revision of the IGRF are extracted from GSFC(S95-sc). Data sources include the Magsat and POGO satellites, observatory annual means, decimated land survey, marine total-field, aeromagnetic, and repeat data. Random data uncertainties are assigned by statistical binning procedures, while systematic error is accounted for via the correlated weight matrix procedure of Langel et al. (1989). The data are not sufficient to resolve all model parameters, and thus, regularization via quadratic penalty functions is employed. For the internal field this included minimizing the average of the square of the radial field secular variation and acceleration over the core-mantle boundary and through time. Comparison of the GSFC(S95-sc) model with the ufm1 model of Bloxham and Jackson (1992) for their common time span shows good general agreement, especially with respect to secular variation coefficient signatures and overall data statistics. The major differences are manifested in a better fitting of Magsat and POGO data by GSFC(S95-sc), but better fitting of early survey data by ufm1 This is expected and reflects the relative influence of the data and penalty function in the particular model. The external field of GSFC(S95-sc) exhibits a very prominent solar-cycle variation in the q(1)(0) coefficient, though with about a 2-year time lag. The internal field exhibits a well behaved R-n spectrum throughout the time span indicating sufficient constraints being applied to the poorly observed, high-degree secular variation. Finally, the westward drift synthesized for degrees 2 to 5 shows a 0.76 linear correlation with the length-of-day (led) variations of Jordi et al. (1994) when the latter leads the former by 11 years. C1 NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. RP Sabaka, TJ (reprint author), HUGHES STX CORP,LANHAM,MD 20706, USA. RI Sabaka, Terence/D-5618-2012 NR 42 TC 51 Z9 51 U1 0 U2 2 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1997 VL 49 IS 2-3 BP 157 EP 206 PG 50 WC Geosciences, Multidisciplinary SC Geology GA WX170 UT WOS:A1997WX17000004 ER PT J AU Langel, RA Conrad, JA Sabaka, TJ Baldwin, RT AF Langel, RA Conrad, JA Sabaka, TJ Baldwin, RT TI Adjustment of UARS, POGS, and DE-1 satellite magnetic field data for modeling of Earth's main field SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article ID HIGH LATITUDES; DISTURBANCE; OGO-2,4 AB In the absence of Magsat quality satellite magnetic field measurements, the use of data of lesser quality is sought. The DE-1 and UARS satellite magnetic field experiments were not designed for the purpose of modeling Earth's main field. The FOGS satellite acquired data for modeling of Earth's main field, but at a lower accuracy than Magsat. All of these data were acquired with fluxgate magnetometers, which are subject to calibration drifts. On Magsat the fluxgate magnetometer was calibrated in-flight by comparison with a Cesium-Vapor scalar magnetometer. Such calibration is not possible on the satellites considered here, leaving uncertainty as to the accuracy of the resulting data. A formalism is developed to compare the data from these satellites with a field model derived from all other available data. This model included data from Magsat, so it is highly accurate at 1980. Its accuracy at the epochs of the satellites considered then depends upon the accuracy with which the field at 1980 can be extrapolated to future epochs. Adjustment of DE-I data requires estimation of only two parameters for data spanning about 10 years. The resulting adjusted data are in good agreement with the model for those 10 years and exhibit residuals generally interpretable in terms of sources in the ionosphere and magnetosphere. Adjustment parameters of the FOGS data vary substantially over the three years of available data. The resulting residuals indicate that the adjusted data set is suitable for main field modeling up to about degree 10, as used for the International Geomagnetic Reference Field. However, the resulting residuals are considered to be due mainly to error in measurement and not to geophysical sources. Adjustment of the UARS data is more difficult. The data used are not sufficient to resolve all of the adjustment-model parameters. If a priori information regarding the magnetic field from attitude torquer rods is included, the ambiguity is mostly resolved. Residuals after adjustment are of comparable magnitude and quality to those from POGS. C1 HUGHES STX CORP,LANHAM,MD 20706. RP Langel, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. RI Sabaka, Terence/D-5618-2012 NR 19 TC 2 Z9 2 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1997 VL 49 IS 2-3 BP 393 EP 415 PG 23 WC Geosciences, Multidisciplinary SC Geology GA WX170 UT WOS:A1997WX17000018 ER PT J AU Khazanov, GV Krivorutsky, EN Moore, TE Liemohn, MW Horwitz, JL AF Khazanov, GV Krivorutsky, EN Moore, TE Liemohn, MW Horwitz, JL TI Lower hybrid oscillations in multicomponent space plasmas subjected to ion cyclotron waves SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FAST MAGNETOSONIC WAVES; RETURN CURRENT REGION; RING CURRENT; PARTICLE INTERACTIONS; EQUATORIAL MAGNETOSPHERE; SUPRAURORAL REGION; ALFVEN WAVES; TRANSPORT; ACCELERATION; MODEL AB It is found that in multicomponent plasmas subjected to Alfven or fast magnetosonic waves, such as are observed in regions of the outer plasmasphere and ring current-plasmapause overlap, lower hybrid oscillations are generated. The addition of a minor heavy ion component to a proton-electron plasma significantly lowers the low-frequency electric wave amplitude needed for lower hybrid wave excitation. It is found that the lower hybrid wave energy density level is determined by the nonlinear process of induced scattering by ions and electrons; hydrogen ions in the region of resonant velocities are accelerated; and nonresonant particles are weakly heated due to the induced scattering. For a given example, the light resonant ions have an energy gain factor of 20, leading to the development of a high-energy tail in the H+ distribution function due to low-frequency waves. C1 UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. UNIV ALABAMA,CTR SPACE PLASMA & AERONOM RES,HUNTSVILLE,AL 35899. UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. RP Khazanov, GV (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,CODE ES83,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012; Liemohn, Michael/H-8703-2012 OI Moore, Thomas/0000-0002-3150-1137; Liemohn, Michael/0000-0002-7039-2631 NR 55 TC 16 Z9 16 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1997 VL 102 IS A1 BP 175 EP 184 DI 10.1029/96JA02321 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA692 UT WOS:A1997WA69200015 ER PT J AU Ho, CW Horwitz, JL Wilson, GR AF Ho, CW Horwitz, JL Wilson, GR TI Dynamics of the H+ and O+ polar wind in the transition region as influenced by ionospheric convection and electron heating SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CLEFT ION FOUNTAIN; X-B CONVECTION; PLASMA OUTFLOW; KINETIC-MODEL; MAGNETOSPHERE; FEATURES; ALTITUDE; DRIFTS; CAP AB We have conducted a set of systematic generalized semikinetic simulations to study the polar H+/O+ upflows in the ionosphere and transition region as influenced by varying convection. Effects of both frictional ion heating and centrifugal acceleration are included. We find that in regions where the convection electric field is strong (E(i) greater than or equal to 100 mV/m) the steady state polar wind may be characterized as primarily a centrifugally accelerated O+ outflow together with an ambipolar H+ outflow, as a minor component, up to 4 R(E) geocentric distance. Owing to the increase in the O+ upward flow speed, the increase in the O+ density, and the decrease in the H+ flow speed, H+-O+ collisions are important to extended altitudes during enhanced convection periods. The exobase (defined here as the altitude where the O+ scale height is equal to the mean free path of an H+ ion with a speed three thermal speeds larger than the H+ bulk speed) shifts from 1900 km for E(i) = 0 mV/m to 3000 km for E(i) = 100 mV/m. For the range of convection electric fields considered here (E(i) 0 mV/m to E(i) = 100 mV/m), we identify an upper and a lower transition region which coincide roughly with the region of downward and upward H+ heat flux, respectively. A set of relationships between ion parallel speeds and normalized collisional mean free paths was found which are associated with the maximum upward and downward heat flux, regardless of the value of E(i), for steady state conditions. We find that the heated and centrifugally accelerated O+ ions can obtain upward bulk velocities of 5 km/s above 3 R(E) geocentric distance for E(i) greater than or equal to 80 mV/m. These ions exert a large downward drag on the H+ ions which stretches out the tail on the lower velocity side of the distribution creating large downward heat fluxes. These effects may explain features of the large downward heat fluxes observed in the H+ distributions to large altitude by the retarding ion mass spectrometer (RIMS) instrument on DE 1. We have also considered impulsive events, consisting of pulses of cleft associated enhanced convection and elevated electron temperatures, followed by convection across the polar cap. These result in O+ ions falling back into the ionosphere on the dayside and nightside [e.g., Horwitz and Lockwood, 1985]. Downward speeds of 1-2 km/s are seen up to several thousand kilometers altitude which is consistent with DE 1/RIMS observations as presented by Chandler [1995]. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB ES83,HUNTSVILLE,AL 35812. RP Ho, CW (reprint author), UNIV ALABAMA,CTR SPACE PLASMA AERONOM & ASTROPHYS RES,HUNTSVILLE,AL 35899, USA. NR 37 TC 12 Z9 12 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1997 VL 102 IS A1 BP 395 EP 406 DI 10.1029/96JA02986 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA692 UT WOS:A1997WA69200036 ER PT J AU Enloe, CL Cooke, DL Pakula, WA Violet, MD Hardy, DA Chaplin, CB Kirkwood, RK Tautz, MF Bonito, N Roth, C Courtney, G Davis, VA Mandell, MJ Hastings, DE Shaw, GB Griffin, G Sega, RM AF Enloe, CL Cooke, DL Pakula, WA Violet, MD Hardy, DA Chaplin, CB Kirkwood, RK Tautz, MF Bonito, N Roth, C Courtney, G Davis, VA Mandell, MJ Hastings, DE Shaw, GB Griffin, G Sega, RM TI High-voltage interactions in plasma wakes: Results from the charging hazards and wake studies (CHAWS) flight experiments SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MESOSONIC CONDUCTING BODIES; LOW-ENERGY IONS; AE-C SATELLITE; SPACE-SHUTTLE; IONOSPHERIC SATELLITE; COLLISIONLESS PLASMA; BODY-SIZE; EXPANSION; ORBITER; VICINITY AB Data from the charging hazards and wake studies (CHAWS) flight experiments on board space shuttle missions STS-60 and STS-69, during which a negatively biased, high-voltage (0-5 kV) probe was placed in a plasma wake in low Earth orbit, are presented. For these experiments the source of the wake was the 4-m-diameter Wake Shield Facility (WSF), which was operated both as a free-flying spacecraft and attached to the shuttle orbiter's robot arm. Current collection by the biased probe is investigated as a function of the density and temperature of the ambient plasma and the probe's location in the plasma wake. Current collection behavior is determined by the expansion of the high-voltage sheath into the ambient plasma stream. Consistent with preflight predictions, current collection on the probe is highly nonuniform, varying by more than 5 orders of magnitude across the surface of the probe. The onset of current collection, however, begins at voltages that are an order of magnitude lower than anticipated. This is likely due to the low-energy, turbulent plasma (typically 2-5% of the ambient density and up to 40% on occasion) observed in the ambient environment. This important minority constituent of the plasma was observed in the vicinity of the shuttle Orbiter and observed while the WSF was free-flying. C1 RADEX INC,BEDFORD,MA 01730. PHILLIPS LAB,GEOPHYS DIRECTORATE,BEDFORD,MA 01731. MAXWELL LABS INC,S CUBED DIV,LA JOLLA,CA 92038. MIT,CAMBRIDGE,MA 02139. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP Enloe, CL (reprint author), USAF ACAD,2354 FAIRCHILD DR,SUITE 2A6,COLORADO SPRINGS,CO 80840, USA. RI Hastings, Daniel/J-3774-2015 OI Hastings, Daniel/0000-0003-4421-5110 NR 52 TC 9 Z9 12 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1997 VL 102 IS A1 BP 425 EP 433 DI 10.1029/96JA02931 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA692 UT WOS:A1997WA69200039 ER PT J AU Smith, LC Forster, RR Isacks, BL Hall, DK AF Smith, LC Forster, RR Isacks, BL Hall, DK TI Seasonal climatic forcing of alpine glaciers revealed with orbital synthetic aperture radar SO JOURNAL OF GLACIOLOGY LA English DT Article ID GREENLAND ICE-SHEET; SURFACE-PROPERTIES; MASS BALANCE; SAR IMAGERY AB The evolution of four dynamic radar glacier zones at the surface of an alpine icefield in British Columbia is monitored using a time series of 35 First European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) images acquired from 1992 to 1994. These zones result from changing wetness and textural properties, and appear to represent: (1) cold snow with no liquid water present; (2) an initial melt front with an upper boundary near the elevation of the 0 degrees isotherm; (3) metamorphosed, rapidly melting first-year snow with a rough or pitted surface; and (4) bare ice. This interpretation is aided by temperature and runoff data, air photographs and field measurements of snowpack properties acquired simultaneously with two ERS-1 SAR scenes, ice-surface elevations derived from 1:50000 topographic maps and simulations or radar backscatter from a geometric optics model of surface scattering. Meltwater production is affected by the development of zones (2), (3) and (4), which form, migrate up-elevation and disappear each year between April and September. C1 Cornell Univ, Dept Geol Sci, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Sci, Greenbelt, MD 20771 USA. RP Smith, LC (reprint author), Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA. RI Hall, Dorothy/D-5562-2012; Smith, Laurence/E-7785-2012 OI Smith, Laurence/0000-0001-6866-5904 NR 42 TC 25 Z9 26 U1 0 U2 1 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1997 VL 43 IS 145 BP 480 EP 488 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA ZC255 UT WOS:000072558500014 ER PT J AU Juang, JN AF Juang, JN TI Unification of several system realization algorithms SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID IDENTIFICATION; MODELS; ONLINE AB Unification of several system realization algorithms is presented using a generalized version of information matrix consisting of shifted input and output data correlations. The relationship of these realization algorithms is established using matrix factorization of the information matrix. The basis vectors of the column space and the null space of the information matrix are the key elements that provide the link among different realization algorithms. Frequency-domain versions of these realization algorithms are also introduced using the information matrix computed from the frequency response data. Experimental examples are given to illustrate the validity and usefulness of these algorithms with some comparison. RP Juang, JN (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 17 TC 4 Z9 4 U1 0 U2 3 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 JAN-FEB PY 1997 VL 20 IS 1 BP 67 EP 73 DI 10.2514/2.3996 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WC645 UT WOS:A1997WC64500009 ER PT J AU Morelli, EA Klein, V AF Morelli, EA Klein, V TI Accuracy of aerodynamic model parameters estimated from flight test data SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB An important part of building mathematical models based on measured data is calculating the accuracy associated with statistical estimates of the model parameters. Indeed, without some idea of this accuracy, the parameter estimates themselves have limited value. An expression is developed for computing quantitatively correct parameter accuracy measures for maximum likelihood parameter estimates when the output residuals are colored. This result is important because experience in analyzing flight test data reveals that the output residuals from maximum likelihood estimation are almost always colored. The calculations involved can be appended to conventional maximum likelihood estimation algorithms. Monte Carlo simulation runs were used to show that parameter accuracy measures from the new technique accurately reflect the quality of the parameter estimates from maximum likelihood estimation without the need for correction factors or frequency domain analysis of the output residuals. The technique was applied to flight test data from repeated maneuvers down on the F-18 High Alpha Research Vehicle. As in the simulated cases, parameter accuracy measures from the new technique were in agreement with the scatter in the parameter estimates from repeated maneuvers, whereas conventional parameter accuracy measures were optimistic. C1 LOCKHEED MARTIN ENGN & SCI CO,HAMPTON,VA 23681. GEORGE WASHINGTON UNIV,HAMPTON,VA 23681. RP Morelli, EA (reprint author), NASA,LANGLEY RES CTR,JOINT INST ADV FLIGHT SCI,MS 132,HAMPTON,VA 23681, USA. NR 18 TC 22 Z9 23 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 JAN-FEB PY 1997 VL 20 IS 1 BP 74 EP 80 DI 10.2514/2.3997 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WC645 UT WOS:A1997WC64500010 ER PT J AU Lim, KB AF Lim, KB TI Disturbance rejection approach to actuator and sensor placement SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID MODEL-REDUCTION RP Lim, KB (reprint author), NASA,LANGLEY RES CTR,GUIDANCE & CONTROL BRANCH,FLIGHT DYNAM & CONTROLS DIV,MS 161,HAMPTON,VA 23681, USA. NR 9 TC 32 Z9 32 U1 0 U2 3 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 JAN-FEB PY 1997 VL 20 IS 1 BP 202 EP 204 DI 10.2514/2.4022 PG 3 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WC645 UT WOS:A1997WC64500033 ER PT J AU BarItzhack, IY Harman, RR AF BarItzhack, IY Harman, RR TI Optimized TRIAD algorithm for attitude determination SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation, and Control Conference and Exhibit CY JUL 29-31, 1996 CL SAN DIEGO, CA SP AIAA C1 NASA,GODDARD SPACE FLIGHT CTR,FLIGHT MECH BRANCH,GREENBELT,MD 20771. NR 4 TC 17 Z9 29 U1 1 U2 10 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 JAN-FEB PY 1997 VL 20 IS 1 BP 208 EP 211 DI 10.2514/2.4025 PG 4 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA WC645 UT WOS:A1997WC64500036 ER PT J AU Sciuto, A AF Sciuto, A TI TCP over ATM: performance results from a testing site SO JOURNAL OF HIGH SPEED NETWORKS LA English DT Article AB Because Transmission Control Protocol (TCP) is widely used to reliably transport data, there is considerable interest in its performance over Asynchronous Transfer Mode (ATM). Much research has been done in this area and results are available, mainly from computer simulations. However, simulation results do not contain the steps required by the user to optimize TCP performance. Nascom needed that information. This paper addresses different tests. it uses each test summary as an example for a specific issue. The summaries include configuration, results, and comments. The hardware and software used also are listed. Based on NASA Communications (Nascom) test results, this paper shows that existing router implementations degrade TCP over ATM performance, that unspecified bit rate (UBR) is preferred over variable bit rate (VER) for a traffic contract, and that multiple streams fairly share one ATM network. C1 NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Sciuto, A (reprint author), NASA, Goddard Space Flight Ctr, Comp Sci Corp, Code 540, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0926-6801 J9 J HIGH SPEED NETW JI J. High Speed Netw. PY 1997 VL 6 IS 3 BP 207 EP 214 PG 8 WC Computer Science, Information Systems SC Computer Science GA YW229 UT WOS:000071911400004 ER PT J AU Fang, A Pierson, DL Mishra, SK Koenig, DW Demain, AL AF Fang, A Pierson, DL Mishra, SK Koenig, DW Demain, AL TI Secondary metabolism in simulated microgravity: beta-lactam production by Streptomyces clavuligerus SO JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY LA English DT Article DE simulated microgravity; gravity; beta-lactam antibiotics; Streptomyces clavuligerus; space microbiology ID LYSINE AB Rotating bioreactors designed at NASA's Johnson Space Center were used to simulate a microgravity environment in which to study secondary metabolism, The system examined was p-lactam antibiotic production by Streptomyces clavuligerus, Both growth and p-lactam production occurred in simulated microgravity, Stimulatory effects of phosphate and L-lysine, previously detected in normal gravity, also occurred in simulated microgravity, The degree of p-lactam antibiotic production was markedly inhibited by simulated microgravity. C1 MIT,DEPT BIOL,FERMENTAT MICROBIOL LAB,CAMBRIDGE,MA 02139. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. KRUG LIFE SCI INC,HOUSTON,TX 77058. NR 14 TC 27 Z9 33 U1 0 U2 5 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE, HAMPSHIRE, ENGLAND RG21 6XS SN 0169-4146 J9 J IND MICROBIOL BIOT JI J. Ind. Microbiol. Biotechnol. PD JAN PY 1997 VL 18 IS 1 BP 22 EP 25 DI 10.1038/sj.jim.2900345 PG 4 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA WM859 UT WOS:A1997WM85900006 PM 9079284 ER PT J AU Jones, WR AF Jones, WR TI Perfluoropolyether lubricants SO JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS LA Japanese DT Review DE perfluoropolyether; liquid lubricant; boundary lubricant; viscosity properties; surface modification; degradation ID HIGH-VACUUM; SOLUBLE ADDITIVES; SURFACE-CHEMISTRY; TEMPERATURE; PERFORMANCE; FLUIDS; SPECTROSCOPY; DESORPTION; (C2F5)(2)O; ETHERS RP Jones, WR (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 46 TC 1 Z9 1 U1 1 U2 4 PU JAPAN SOC TRIBOLOGISTS PI TOKYO PA KIKAI SHINKO KAIKAN NO 407-2 5-8 SHIBA-KOEN 3-CHOME MINATO-KU, TOKYO 105, JAPAN SN 0915-1168 J9 J JPN SOC TRIBOLOGIS JI J. Jpn. Soc. Tribol. PY 1997 VL 42 IS 3 BP 205 EP 210 PG 6 WC Engineering, Mechanical SC Engineering GA WV094 UT WOS:A1997WV09400008 ER PT J AU Miller, CE Sander, SP AF Miller, CE Sander, SP TI The nu(4) band of FNO2 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID LINE STRENGTHS; SPECTRUM AB The high-resolution infrared spectrum of nitryl fluoride, FNO2, has been observed in the 1750-1825 cm(-1) region. The spectrum displays extensive rotational structure consisting solely of b-type transitions and is assigned to nu(4), the NO2 antisymmetric stretching vibration. Over 1500 infrared and 51 microwave transitions have been fitted to generate rotational constants for the nu(4) = 1 state (nu(0) = 1793.466822 cm(-1)) and improved constants for the ground state. Rotationally resolved infrared line positions are now available for the identification of FNO2, an atmospheric product of CFC and HFC oxidation. (C) 1997 Academic Press, Inc. RP Miller, CE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 32 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JAN PY 1997 VL 181 IS 1 BP 18 EP 23 DI 10.1006/jmsp.1996.7163 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA WA945 UT WOS:A1997WA94500003 ER PT J AU Balboni, J Cohen, SA Munsat, T AF Balboni, J Cohen, SA Munsat, T TI Arc jets for divertor component testing SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 12th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices CY MAY 20-24, 1996 CL ST RAPHAEL, FRANCE SP Assoc EURATOM CEA Fus Controlee, European Comm, DGII, Conseil Reg Provence, Alpes, Cote d Azur DE divertor plasma; divertor simulator; plasma-wall interactions simulator; fusion technology AB This paper describes the potential for are jet facilities to simulate the thermal and chemical environment inside a fusion-reactor power and particle exhaust section to provide the fusion materials science and plasma physics communities with data on their models and component designs. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Balboni, J (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PY 1997 VL 241 BP 483 EP 488 DI 10.1016/S0022-3115(97)80085-2 PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA XF377 UT WOS:A1997XF37700061 ER PT J AU Ghosh, S Goldstein, ML AF Ghosh, S Goldstein, ML TI Anisotropy in hall MHD turbulence due to a mean magnetic field SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID SOLAR-WIND FLUCTUATIONS; DISPERSIVE ALFVEN WAVES; MAGNETOHYDRODYNAMIC TURBULENCE; PARAMETRIC-INSTABILITIES; ROTATIONAL DISCONTINUITIES; NONLINEAR EVOLUTION; HELICITY; MAGNETOFLUID; EXCITATION; DAUGHTER AB The development of anisotropies in an initially isotropic spectrum is studied numerically for compressible magnetohydrodynamic (MHD) turbulence in the presence of the Hall term. Building on a previous study where it was shown that. spectral cascades in the Hall MHD system differ from the standard MHD case, particularly at high cross-helicities, we use an isotropic high cross-helicity initial state to study anisotropies of the Hall MHD system for a variety of mean magnetic field strengths and sonic Mach numbers. Strong anisotropies, which maximize at the ion-inertial length scale, appear for several plasma states and are categorized according to their plasma beta beta: high-beta Hall MHD simulations (beta > 1) show strong anisotropies relative to the standard MHD case, intermediate-beta Hall MHD simulations (beta approximate to 1) show smaller anisotropy differences relative to the standard MHD case, and low-beta Hall MHD simulations (beta < 1) again show strong anisotropies relative to the standard model. It is suggested that these anisotropy enhancements are due to nonlinear cascade suppression of propagating Alfven waves in the field-aligned direction. This is different from the dynamics in the highly oblique directions, where nonpropagating density and magnetic-energy anticorrelations appear. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP Ghosh, S (reprint author), APPL RES CORP,8201 CORP DR,SUITE 1120,LANDOVER,MD 20785, USA. RI Goldstein, Melvyn/B-1724-2008 NR 41 TC 38 Z9 39 U1 1 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD JAN PY 1997 VL 57 BP 129 EP 154 DI 10.1017/S0022377896005260 PN 1 PG 26 WC Physics, Fluids & Plasmas SC Physics GA WY352 UT WOS:A1997WY35200009 ER PT J AU Vahala, G Vahala, L Morrison, J Krasheninnikov, S Sigmar, D AF Vahala, G Vahala, L Morrison, J Krasheninnikov, S Sigmar, D TI K-epsilon compressible 3D neutral fluid turbulence modelling of the effect of toroidal cavities on flame-front propagation in the gas-blanket regime for tokamak divertors SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID RENORMALIZATION-GROUP; CHANNEL; FLOWS AB Recent experiments and 2D laminar plasma-fluid simulations have indicated that plasma. detachment from the divertor plate is strongly tied to plasma recombination. With plasma recombination, a neutral gas blanket, will form between the divertor plate and the plasma frame front. Because of plasma-neutral coupling, the plasma flow along the field lines will drive neutral gas flow with Mach number greater than or equal to 1 and Reynolds number greater than or equal to 1000. A compressible set of conservation and transport equations are solved with 2D mean toroidal flow and 3D turbulence effects over various toroidal cavity geometries. The radial structure of the temperature profile is determined for both turbulent and laminar flow as the flame front propagates down the toroidal cavity. Quantitative results are obtained for the increased heat, transfer to the toroidal walls due to turbulence as well as radial profiles for the transport coefficients. It is found that, heat loads to the toroidal walls can be increased by factors of 5-20 over that for laminar flow for the cavity geometries studied here. This increased heat transfer to the toroidal walls will lead to decreased levels of heat flux impinging on the divertor plate. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23666. OLD DOMINION UNIV,DEPT ELECT & COMP ENGN,NORFOLK,VA 23527. ANALYT SERV & MAT INC,HAMPTON,VA 23666. MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. RP Vahala, G (reprint author), COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187, USA. NR 30 TC 1 Z9 1 U1 1 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD JAN PY 1997 VL 57 BP 155 EP 173 DI 10.1017/S0022377896005235 PN 1 PG 19 WC Physics, Fluids & Plasmas SC Physics GA WY352 UT WOS:A1997WY35200010 ER PT J AU Martinez, DO Chen, S Doolen, GD Kraichnan, RH Wang, LP Zhou, Y AF Martinez, DO Chen, S Doolen, GD Kraichnan, RH Wang, LP Zhou, Y TI Energy spectrum in the dissipation range of fluid turbulence SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID ISOTROPIC TURBULENCE; NUMERICAL TURBULENCE; VELOCITY; FLOWS AB High-resolution, direct numerical simulations of three-dimensional incompressible Navier-Stokes equations are carried out to study the energy spectrum in the dissipation range. An energy spectrum of the form A (k/k(d))(alpha)exp[-beta k/k(d)] is confirmed. The possible values of the parameters alpha and beta, as well as their dependence on Reynolds numbers and length scales, are investigated, showing good agreement with recent theoretical predictions. A 'bottleneck'-type effect. is reported at k/k(d) approximate to 4, exhibiting a possible transition from near-dissipation to far-dissipation. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. IBM CORP,THOMAS J WATSON RES CTR,DIV RES,YORKTOWN HTS,NY 10598. UNIV DELAWARE,DEPT MECH ENGN,NEWARK,DE 19716. NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23861. RP Martinez, DO (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Chen, Shiyi/A-3234-2010; Wang, Lian-Ping/N-7516-2016 OI Wang, Lian-Ping/0000-0003-4276-0051 NR 21 TC 40 Z9 41 U1 2 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD JAN PY 1997 VL 57 BP 195 EP 201 DI 10.1017/S0022377896005338 PN 1 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY352 UT WOS:A1997WY35200013 ER PT J AU Copenhaver, WW Puterbaugh, SL Hah, C AF Copenhaver, WW Puterbaugh, SL Hah, C TI Unsteady flow and shock motion in a transonic compressor rotor SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID TIP-CLEARANCE; FAN; STAGE AB The results of an experimental and numerical comparison of the unsteadiness and shock motion that occurs in the tip region within a modern, low-aspect-ratio, high-through-flow, axial-how transonic fan rotor are presented, The unsteadiness studied here is associated with local phenomena within the blade passage and not related to blade row interaction, Unsteady static pressures were measured at the casing over the rotor that operates at a tip relative Mach number of 1.6. An unsteady three-dimensional Navier-Stokes computational study was performed with tip clearance comparable to the test rotor. The fully three-dimensional, unsteady, Reynolds-averaged Navier-Stokes equations were solved with time steps, each nominally of 2.8 x 10(-5) s in duration or approximately live times blade pass frequency. The results in the clearance gap were retained from the computational solution and compared with the experimental measurements. Both indicated deterministic unsteadiness near the location of the shock, nigh levels of unsteadiness were also measured downstream of the shock in the path of the clearance vortex, but this phenomenon was not predicted by the computation, The unsteadiness near the shock was shown to be a result of movement of the shock. The amplitude and frequency of shock position oscillation was estimated from the results to be about 2% chord and 2 kHz, respectively, Analysis of loss caused by the shock unsteadiness suggested that losses because of shock motion were insignificant relative to the steady shock loss at the relative Mach number studied. C1 NASA, LEWIS RES CTR, INTERNAL FLUID MECH DIV, CLEVELAND, OH 44135 USA. RP Copenhaver, WW (reprint author), USAF, WRIGHT LAB,AEROPROP & POWER DIRECTORATE,POTF, 1950 5TH ST, BLDG 18, WRIGHT PATTERSON AFB, OH 45433 USA. NR 37 TC 10 Z9 10 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 JAN-FEB PY 1997 VL 13 IS 1 BP 17 EP 23 DI 10.2514/2.5145 PG 7 WC Engineering, Aerospace SC Engineering GA WC621 UT WOS:A1996WC62100003 ER PT J AU McConley, MW Chubb, DL McMaster, MS Afjeh, AA AF McConley, MW Chubb, DL McMaster, MS Afjeh, AA TI Stability of thin liquid sheet flows SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID INSTABILITY AB A two-dimensional, linear stability analysis of a thin nonplanar liquid sheet flow in vacuum is carried out. A sheet now created by a narrow slit of W and tau attains a nonplanar cross section as a consequence of cylinders forming on the sheet edge under the influence of surface tension forces, The region where these edge cylinders join the sheet is one of high curvature, and this is found to be the location where instability is most likely to occur, The sheet now is found to be unstable, but with low growth rates for symmetric wave disturbances and high growth rates for antisymmetric disturbances, By combining the symmetric and antisymmetric disturbance modes, a wide range of stability characteristics is obtained, The product of unstable growth rate and now time is proportional to the width-to-thickness ratio of the slit generating the sheet. Three-dimensional effects can alter these results, particularly when the sheet length-to-width ratio is not much greater than unity. C1 NASA, LEWIS RES CTR, PHOTOVOLTA BRANCH, CLEVELAND, OH 44135 USA. UNIV TOLEDO, DEPT MECH ENGN, TOLEDO, OH 43606 USA. RP McConley, MW (reprint author), MIT, DEPT AERONAUT ENGN, CAMBRIDGE, MA 02139 USA. NR 19 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1997 VL 13 IS 1 BP 74 EP 81 DI 10.2514/2.5131 PG 8 WC Engineering, Aerospace SC Engineering GA WC621 UT WOS:A1996WC62100010 ER PT J AU Krishnamurthy, R Rogers, RC Tiwari, SN AF Krishnamurthy, R Rogers, RC Tiwari, SN TI Numerical study of hypervelocity flows through a scramjet combustor SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Results are reported from a numerical investigation of mixing and combustion of hydrogen injected into an airstream at high enthalpy (flight Mach number 17). Numerical computations performed using the general aerodynamic simulation program code are compared with experimental data obtained with a rectangular combustor model in the free-piston driven, reflected-shock tunnel facility T5, at the Graduate Aeronautical Laboratories at the California Institute of Technology, Computed results show good agreement with the measured static wall pressures, Mixing performance with the injection of hot hydrogen is shown to be in line with established correlations for scramjet design. Also, the issue of spatial uniformity of the hydrogen-air mixture has been explored. C1 N CAROLINA AGR & TECH STATE UNIV, GREENSBORO, NC 27411 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. OLD DOMINION UNIV, NORFOLK, VA 23529 USA. NR 18 TC 2 Z9 3 U1 0 U2 2 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 EI 1533-3876 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1997 VL 13 IS 1 BP 131 EP 141 DI 10.2514/2.5138 PG 11 WC Engineering, Aerospace SC Engineering GA WC621 UT WOS:A1996WC62100017 ER PT J AU Momoh, J Chattopadhyay, D Dolce, JL AF Momoh, J Chattopadhyay, D Dolce, JL TI Mixed integer programming-based power scheduler for the space station SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID APPROXIMATION AB This paper proposes a new mixed integer programming-based optimization model for power scheduling in a space power system, The model has the capability of handling multiple objectives by maximizing the available sources of energy and minimizing the variation of loads over a day. It can also incorporate several complex interactions between the loads in a space system. The modeling framework is illustrated using a simplistic case study for the Space Station Freedom. Detailed results and inputs to the model are presented and several potential enhancements of the model have been summarized. C1 NASA, LEWIS RES CTR, SPACE STN FREEDOM ELECT SYST, CLEVELAND, OH 44135 USA. RP Momoh, J (reprint author), HOWARD UNIV, DEPT ELECT ENGN, CTR ENERGY SYST & CONTROL, WASHINGTON, DC 20059 USA. NR 15 TC 0 Z9 0 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 JAN-FEB PY 1997 VL 13 IS 1 BP 150 EP 156 DI 10.2514/2.5140 PG 7 WC Engineering, Aerospace SC Engineering GA WC621 UT WOS:A1996WC62100019 ER PT J AU Gotsis, PK Chamis, CC Minnetyan, L AF Gotsis, PK Chamis, CC Minnetyan, L TI Progressive fracture of fiber composite build-up structures SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE laminated thin shells; laminated cylinders; composite structures; computational simulation; structural analysis; finite element analysis; damage; degradation; durability; fracture; stiffened panel; structural degradation AB Damage progression and fracture of built-up composite structures is evaluated by using computational simulation. The objective is to examine the behavior and response of a stiffened composite (0/ +/- 45/90)(s6) laminate panel by simulating the damage initiation, growth, accumulation, progression and propagation to structural collapse, An integrated computer code (CODSTRAN was augmented for the simulation of the progressive damage and fracture of built-up composite structures under mechanical loading, Results show that damage initiation and progression to have significant effect on the structural response. Influence of the type of loading is investigated on the damage initiation, propagation and final fracture of the build-up composite panel. C1 CLARKSON UNIV,DEPT CIVIL & ENVIRONM ENGN,POTSDAM,NY 13699. RP Gotsis, PK (reprint author), NASA,LEWIS RES CTR,STRUCT DIV,CLEVELAND,OH 44135, USA. NR 8 TC 1 Z9 1 U1 0 U2 2 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PY 1997 VL 16 IS 2 BP 182 EP 198 PG 17 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA WP107 UT WOS:A1997WP10700007 ER PT J AU Minnetyan, L Chamis, CC AF Minnetyan, L Chamis, CC TI Structural durability of damaged metallic panel repaired with composite patches SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article ID FRACTURE AB Structural durability/damage tolerance characteristics of an aluminum tension specimen possessing a short crack and repaired by applying a fiber composite surface patch is investigated via computational simulation. The composite patch is made of graphite/epoxy plies with various layups. An integrated computer code that accounts for all possible failure modes is utilized for the simulation of combined fiber-composite/aluminum structural degradation under loading. Damage initiation, growth, accumulation, and propagation to structural fracture are included in the simulation. Results show the structural degradation stages due to tensile loading and illustrate the use of computational simulation for the investigation of a composite patch repaired cracked metallic panel. C1 NASA,LEWIS RES CTR,STRUCT DIV,CLEVELAND,OH 44135. RP Minnetyan, L (reprint author), CLARKSON UNIV,POTSDAM,NY 13699, USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PY 1997 VL 16 IS 3 BP 200 EP 216 PG 17 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA WP639 UT WOS:A1997WP63900001 ER PT J AU Gotsis, PK Chamis, CC Minnetyan, L AF Gotsis, PK Chamis, CC Minnetyan, L TI Progressive fracture of blade containment composite structures SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article; Proceedings Paper CT 54th Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers DE thin shells; fiber composites; computational simulation; structural analysis; impact load; dynamics; finite element damage; degradation; fracture; graphite fibers; epoxy matrix AB Damage progression and penetration of blade containment composite structures due to impact load is evaluated by using computational simulation. An integrated computer code (CODSTRAN) was modified to simulate the progressive damage and penetration of composite structures under impacting loading. The objective of this work is to describe the modification required in order to evaluate the response of a containment fiber composite structure hit by an escaped blade. The simulation traces the history of damage initiation. growth, accumulation, progression and propagation to containment or penetration. Results show that the initial velocity of the escaped blade determines the damage initiation, propagation and containment or penetration containment composite structure of specified laminate thickness and configuration. C1 CLARKSON UNIV,DEPT CIVIL & ENVIRONM ENGN,POTSDAM,NY 13676. RP Gotsis, PK (reprint author), NASA,LEWIS RES CTR,STRUCT DIV,CLEVELAND,OH 44101, USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PY 1997 VL 16 IS 15 BP 1407 EP 1424 PG 18 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA YB745 UT WOS:A1997YB74500005 ER PT J AU Minnetyan, L Gotsis, PK Chamis, CC AF Minnetyan, L Gotsis, PK Chamis, CC TI Progressive damage and fracture of unstiffened and stiffened composite pressure vessels SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE burst pressure; composites; composite structures; damage; degradation; durability; fracture; laminates; pressure vessels; simulation; structural fracture AB Structural durability and damage tolerance characteristics of pressurized graphite/epoxy laminated thin composite cylinders are investigated via computational simulation. Both unstiffened and integral hoop stiffened cylinders are considered. A computer code is utilized for the simulation of composite structural degradation under loading. Damage initiation, growth, accumulation, and propagation to structural fracture are included in the simulation. The increase of burst pressure due to hoop stiffening is quantified. Results demonstrate the significance of the type and size of local defects on the structural durability of pressurized composite cylindrical shells. C1 Clarkson Univ, Dept Civil & Environm Engn, Potsdam, NY 13699 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Minnetyan, L (reprint author), Clarkson Univ, Dept Civil & Environm Engn, Potsdam, NY 13699 USA. NR 9 TC 4 Z9 4 U1 1 U2 1 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PY 1997 VL 16 IS 18 BP 1711 EP 1724 PG 14 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA YQ639 UT WOS:000071408400006 ER PT J AU Zoby, EV AF Zoby, EV TI A message from the editor-in-chief SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material RP Zoby, EV (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1997 VL 34 IS 1 BP 1 EP 3 PG 3 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500001 ER PT J AU Blanchard, RC Wilmoth, RG LeBeau, GJ AF Blanchard, RC Wilmoth, RG LeBeau, GJ TI Rarefied-flow transition regime orbiter aerodynamic acceleration flight measurements SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SHUTTLE ORBITER AB Acceleration data taken for the first time from the orbital acceleration research experiment during re-entry on Space Transportation System-62 have been analyzed using in situ calibration factors, The re-entry data include the flight regime from orbital altitudes down to about 90 km, which covers the free-molecule-flow regime and the upper altitude fringes of the rarefied-flow transition into the hypersonic continuum, Ancillary flight data on Orbiter position, orientation, velocity, and rotation rates have been used in models to transform the measured accelerations to the Orbiter center of gravity, from which aerodynamic accelerations along the Orbiter body axes have been calculated, Residual offsets introduced in the measurements by unmodeled Orbiter forces are identified and removed, The resulting aerodynamic acceleration measurements along the Orbiter's body axis and the normal to axial acceleration ratio in the free-molecule-flow and transition-flow regimes are presented, and there is excellent agreement when compared with numerical simulations from three direct simulation Monte Carlo codes, Also, there is good agreement with a direct comparison between the experiment flight data and an independent microgravity accelerometer experiment, the high-resolution accelerometer package, which also obtained flight data on re-entry during the mission down to about 95 km. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP Blanchard, RC (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 18 TC 6 Z9 7 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1997 VL 34 IS 1 BP 8 EP 15 DI 10.2514/2.3183 PG 8 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500003 ER PT J AU Oleson, SR Myers, RM Kleuver, CA Riehl, JP Curran, FM AF Oleson, SR Myers, RM Kleuver, CA Riehl, JP Curran, FM TI Advanced propulsion for geostationary orbit insertion and North-South station keeping SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Solar electric propulsion technology is currently being used for geostationary satellite station keeping. Analyses show that electric propulsion technologies can be used to obtain additional increases in payload mass by using them to perform part of the orbit transfer. Three electric propulsion technologies are examined at two power levels for geostationary insertion of an Atlas IIAS class spacecraft. The onboard chemical propulsion apogee engine fuel is reduced in this analysis to allow the use of electric propulsion. A numerical optimizer is used to determine the chemical burns that will minimize the electric propulsion transfer times. For a 1550-kg Atlas IIAS class payload, increases in net mass (geostationary satellite mass less wet propulsion system mass) of 150-800 kg are enabled by using electric propulsion for station keeping, advanced chemical engines for part of the transfer, and electric propulsion for the remainder of the transfer. Trip times are between one and four months. C1 NYMA INC,AEROSP TECHNOL DEPT,SPACE PROP TECHNOL SECT,BROOKPARK,OH 44142. UNIV MISSOURI,KANSAS CITY,MO 64110. NASA,LEWIS RES CTR,ON BOARD PROP BRANCH,CLEVELAND,OH 44135. RP Oleson, SR (reprint author), NYMA INC,AEROSP ANAL SECT,BROOKPARK,OH 44142, USA. NR 20 TC 31 Z9 33 U1 1 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 JAN-FEB PY 1997 VL 34 IS 1 BP 22 EP 28 DI 10.2514/2.3187 PG 7 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500005 ER PT J AU Phillips, WP Engelund, WC AF Phillips, WP Engelund, WC TI Aerodynamics for a winged, circular-body, single-stage-to-orbit spacecraft configuration SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 13th Applied Aerodynamics Conference CY JUN 19, 1995-JUN 22, 1996 CL SAN DIEGO, CA SP AIAA AB Experimental aerodynamic characteristics were obtained fora generic, winged, circular-body, single-stage-to-orbit spacecraft configuration. The baseline configuration was longitudinally stable and trimmable at almost all Mach numbers from 0.15 to 10.0, with the exception occurring at low supersonic speeds. Landing speed and subsonic-to-hypersonic longitudinal stability and control appear to be within design guidelines. A lack of sufficient supersonic longitudinal control power and lateral-directional instabilities found over the entire speed range, however, create a problem area, which could be alleviated by modifying the configuration's directional stabilization devices. Longitudinal aerodynamic predictions made utilizing the Aerodynamic Preliminary Analysis System were in qualitative, and often quantitative, agreement with experimental values. C1 NASA,LANGLEY RES CTR,VEHICLE ANAL BRACH,SPACE & ATMOSPHER SCI PROGRAM GRP,HAMPTON,VA 23681. RP Phillips, WP (reprint author), NASA,LANGLEY RES CTR,RES TECHNOL GRP,MS 408A,HAMPTON,VA 23681, USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1997 VL 34 IS 1 BP 43 EP 47 DI 10.2514/2.3190 PG 5 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500008 ER PT J AU Wolk, G Dreyer, M Rath, HJ Weislogel, MM AF Wolk, G Dreyer, M Rath, HJ Weislogel, MM TI Damped oscillations of a liquid/gas surface upon step reduction in gravity SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID BOUNDARY-CONDITIONS; STEADY MOVEMENT; CAPILLARY-TUBE; CONTACT-ANGLE; MENISCUS; WAVES; PLATE AB The reorientation and settling of a liquid/gas interface in a right circular cylinder upon step reduction in gravity is investigated numerically. A modified dynamic contact angle boundary condition is implemented where the hysteresis parameter gamma is employed as an adjustable parameter representing the degree of relative slip at the contact line. The effect of the boundary condition on the axial interface oscillation is studied and the dependence thereon of the resonant frequency and settling time is given. Results are shown regarding the behavior of the dynamic contact angle and the penetration of the surface oscillations into the bulk liquid. The numerical results are tuned via comparisons with existing experimental data, and a method for estimating the appropriate boundary condition providing good agreement is suggested. An accompanying scale analysis depicts gamma as a function of the Ohnesorge number, the cylinder radius, and the static contact angle, These independent parameters are measures of the system damping, characteristic surface deflection, and effective stiffness of the interface, Applications of the results may be made to spacecraft fluids management and the use of spacecraft and/or drop towers for fluids experimentation. C1 NASA,LEWIS RES CTR,MICROGRAV FLUIDS BRANCH,CLEVELAND,OH 44135. RP Wolk, G (reprint author), UNIV BREMEN,INTERFACE PHENOMENA BRANCH,CTR APPL SPACE TECHNOL & MICROGRAV,D-28359 BREMEN,GERMANY. NR 20 TC 10 Z9 10 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 JAN-FEB PY 1997 VL 34 IS 1 BP 110 EP 117 DI 10.2514/2.3179 PG 8 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500017 ER PT J AU Verderaime, V Vaughan, R AF Verderaime, V Vaughan, R TI U-groove aluminum weld strength improvement SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Though butt-welds are among the most preferred joining methods in aerostructures, their strength dependence on inelastic mechanics is generally the least understood. This study investigated experimental strain distributions across a thick aluminum U-grooved weld and identified two weld process considerations for improving the multipass weld strength. One is the source of peaking in which the extreme thermal expansion and contraction gradient of the fusion heat input across the groove tab thickness produces severe angular distortion that induces bending under uniaxial Loading. The other is the filler strain hardening decreasing with increasing filler pass sequences, producing the weakest welds on the last weld pass side. Both phenomena are governed by weld pass sequences. Many industrial welding schedules unknowingly compound these effects, which reduce the weld strength. A depeaking index model was developed to select filler pass thickness, pass numbers, and sequences to improve depeaking In the welding process. The result was to select the number and sequence of weld passes to reverse the peaking angle such as to combine the strongest weld pass side with the peaking induced bending tension component side to provide a more uniform stress and stronger weld under axial tensile loading. RP Verderaime, V (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT & DYNAM LAB,HUNTSVILLE,AL 35812, USA. NR 7 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 JAN-FEB PY 1997 VL 34 IS 1 BP 133 EP 136 DI 10.2514/2.3182 PG 4 WC Engineering, Aerospace SC Engineering GA WG795 UT WOS:A1997WG79500020 ER PT J AU Jayasimha, DN Hayder, ME Pillay, SK AF Jayasimha, DN Hayder, ME Pillay, SK TI An evaluation of architectural platforms for parallel Navier-Stokes computations SO JOURNAL OF SUPERCOMPUTING LA English DT Article DE computational fluid dynamics; Navier-Stokes and Euler equations; computation and communication; scalability; shared memory; distributed memory; network of workstations; interconnection network; message-passing library AB We study the computational, communication, and scalability characteristics of a computational fluid dynamics application, which solves the time-accurate flow field of a jet using the compressible Navier-Stokes equations, on a variety of parallel architectural platforms. The platforms chosen for this study are a cluster of workstations (the LACE experimental testbed at NASA Lewis), a shared-memory multiprocessor (the GRAY Y-MP), and distributed-memory multiprocessors with different topologies (the IBM SP and the GRAY T3D). We investigate the impact of various networks connecting the cluster of workstations on the performance of the application and the overheads induced by popular message-passing libraries used for parallelization. The work also highlights the importance of matching the memory bandwidth to processor speed for good single processor performance. By studying the performance of an application on a variety of architectures, we are able to point out the strengths and weaknesses of each of the example computing platforms. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. NASA,LEWIS RES CTR,SCI ENGN COMP SOLUT OFF,CLEVELAND,OH 44142. RP Jayasimha, DN (reprint author), INTEL CORP,PLATFORM ARCHITECTURE GRP IA64,SANTA CLARA,CA 95052, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-8542 J9 J SUPERCOMPUT JI J. Supercomput. PY 1997 VL 11 IS 1 BP 41 EP 60 DI 10.1023/A:1007961312671 PG 20 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA YE913 UT WOS:A1997YE91300003 ER PT J AU Wang, J Liewer, P Huang, E AF Wang, J Liewer, P Huang, E TI Three-dimensional electromagnetic particle-in-cell with Monte Carlo collision simulations on three MIMD parallel computers SO JOURNAL OF SUPERCOMPUTING LA English DT Article DE parallel algorithm; particle simulation; PIC; MCC ID CRITICAL IONIZATION VELOCITY AB A three-dimensional electromagnetic particle-in-cell code with Monte Carlo collision (PIC-MCC) is developed for MIMD parallel supercomputers. This code uses a standard relativistic leapfrog scheme incorporating Monte Carlo calculations to push plasma particles and to include collisional effects on particle orbits. A local finite-difference time-domain method is used to update the self-consistent electromagnetic fields. The code is implemented using the General Concurrent PIC (GCPIC) algorithm, which uses domain decomposition to divide the computation among the processors. Particles must be exchanged between processors as they move among subdomains. Message passing is implemented using the Express Cubix library and the PVM. We evaluate the performance of this code using a 512-processor Intel Touchstone Delta, a 512-processor Intel Paragon, and a 256-processor CRAY T3D. It is shown that a high parallel efficiency exceeding 95% has been achieved on all three machines for large problems. We have run PIC-MCC simulations using several hundred million particles with several million collisions per time step. For these large-scale simulations the particle push time achieved is in the range of 90-115 ns/particle/time step, and the collision calculation time in the range of a few hundred nanoseconds per collision. RP Wang, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 18 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-8542 J9 J SUPERCOMPUT JI J. Supercomput. PY 1997 VL 10 IS 4 BP 331 EP 348 PG 18 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA XJ161 UT WOS:A1997XJ16100002 ER PT J AU Opila, EJ Hann, RE AF Opila, EJ Hann, RE TI Paralinear oxidation of CVD SiC in water vapor SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID DEPOSITED SILICON-CARBIDE; KINETICS; CERAMICS; OXYGEN AB The oxidation kinetics of CVD SIC mere monitored by thermogravimetric analysis (TGA) in a 50% H2O/50% O-2 gas mixture flowing at 4.4 cm/s for temperatures between 1200 degrees and 1400 degrees C. Paralinear weight change kinetics were observed as the water vapor oxidized the SIC and simultaneously volatilized the silica scale. The long-term degradation rate of SiC is determined by the volatility of the silica scale. Rapid SIC surface recession rates were estimated from these data for actual aircraft engine combustor conditions. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Opila, EJ (reprint author), CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115, USA. NR 34 TC 235 Z9 241 U1 10 U2 41 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JAN PY 1997 VL 80 IS 1 BP 197 EP 205 DI 10.1111/j.1151-2916.1997.tb02810.x PG 9 WC Materials Science, Ceramics SC Materials Science GA WF896 UT WOS:A1997WF89600026 ER PT J AU Baeder, JD Gallman, JM Yu, YH AF Baeder, JD Gallman, JM Yu, YH TI A computational study of the aeroacoustics of rotors in Hover SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article; Proceedings Paper CT 49th Annual Forum of the American-Helicopter-Society CY MAY, 1993 CL ST LOUIS, MO SP Amer Helicopter Soc AB The noise from low-thrusting rotors in hover is examined for a wine range of tip Mach numbers for various blade planforms using several different methods. The first approach is to use an Euler/Navier-Stokes code to calculate the acoustic field without using any acoustic analogy to examine the wavefront formation process and acoustic propagation through a nonlinear flowfield. Furthermore, the near field solutions from the CFD code are used as input to two different methods: a code based on the linear stationary Kirchhoff formulation and a code based on the linear acoustic analogy approach. The results from the CFD code compare very well with the experimental acoustic data available, as do the results from the Kirchhoff code. However, the lack of quadrupole terms in the linear acoustic analogy approach causes the negative peak pressure to be underpredicted by a factor of two in-plane at high tip speeds. This underprediction decreases as an observer moves out-of-plane. Finally, the CFD code is used to study the acoustic field for five different rotor blades, This study provides useful insight into the noise generating mechanisms of various blade planform shapes and near field wavefront formations near the blade. C1 NASA,AMES RES CTR,DIV FLUID MECH,AEROFLIGHTDYNAM DIRECTORATE ATCOM,MOFFETT FIELD,CA 94035. RP Baeder, JD (reprint author), UNIV MARYLAND,DEPT AEROSP ENGN,CTR ROTORCRAFT EDUC & RES,COLLEGE PK,MD 20742, USA. NR 17 TC 12 Z9 15 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 JAN PY 1997 VL 42 IS 1 BP 39 EP 53 PG 15 WC Engineering, Aerospace SC Engineering GA WF418 UT WOS:A1997WF41800004 ER PT J AU Lyrintzis, AS Koutsavdis, EK Strawn, RC AF Lyrintzis, AS Koutsavdis, EK Strawn, RC TI A comparison of computational aeroacoustic prediction methods SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article; Proceedings Paper CT 2nd Aeromechanics Specialists Conference of the American-Helicopter-Society CY OCT 11-13, 1995 CL BRIDGEPORT, CT SP Amer Helicopter Soc ID NOISE AB This paper compares two methods for predicting the noise from helicopter rotors in forward flight. Both methods use a computational fluid dynamics (CFD) solver for the Euler equations to predict the aerodynamic and acoustic solutions in the near field. The first method propagates the near-field noise using the acoustic analogy without quadrupole terms. The second method uses a Kirchhoff integration to propagate the near-field rotor noise to the far field. Computed results from both methods are compared with each other and with experimental data for test cases with both high-speed impulsive and blade-vortex interaction noise. Computed results show that both methods give similar results for cases where there is no transonic flow over the rotor blades. For higher-speed cases with transonic flow, the Kirchhoff method gives more accurate results. Both acoustic prediction methods require similar computational resources, but these requirements are small when compared to those of the CFD now solver. C1 USA, AFDD, NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Lyrintzis, AS (reprint author), PURDUE UNIV, SCH AERONAUT & ASTRONAUT, W LAFAYETTE, IN 47907 USA. NR 15 TC 2 Z9 2 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 JAN PY 1997 VL 42 IS 1 BP 54 EP 57 PG 4 WC Engineering, Aerospace SC Engineering GA WF418 UT WOS:A1997WF41800005 ER PT J AU Hanson, JM Dukemann, GA AF Hanson, JM Dukemann, GA TI Optimization of many-burn orbital transfers SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article ID OPTIMAL LOW-THRUST AB Optimization of medium and low-thrust orbital transfers is important for future upper stages. Previous research has generally either considered a fairly small number of burns with medium thrust or has assumed continuous thrusting for low-thrust transfers. The acceleration level considered in this paper is too high to use orbit averaging and too low (in most cases) to use only a few burns. The optimization scheme used is an optimal control solution for each burn, and a parameter optimization for the ensemble of burns. The solution for each burn is available in open-loop and closed-loop form, so that the method also provides a guidance scheme for Eying the transfers. The optimization includes oblateness terms, complicating many-burn transfers with plane change. Results compare favorably to several published cases. This paper also includes additional transfer cases and parametric results. These results are easy to obtain in comparison with many-burn (non averaged) multi-point boundary value problem solutions, which require the determination of a number of sensitive parameters. Cases examined include transfer to high-Earth orbit, transfer to geostationary orbit, transfer to the Global Positioning System (GPS) orbit, escape from orbit, and transfer to the lunar sphere of influence. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, FLIGHT MECH GUIDANCE NAVIGAT & CONTROL SYST BRANC, HUNTSVILLE, AL 35812 USA. NR 13 TC 2 Z9 7 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JAN-MAR PY 1997 VL 45 IS 1 BP 1 EP 40 PG 40 WC Engineering, Aerospace SC Engineering GA YA340 UT WOS:A1997YA34000001 ER PT J AU EricssonJackson, AJ Bainum, PM Xing, GQ AF EricssonJackson, AJ Bainum, PM Xing, GQ TI Actuator/sensor placement using degree of controllability and observability for digitally controlled orbiting platforms SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS / AIAA Astrodynamics Specialist Conference CY AUG 14-17, 1995 CL HALIFAX, CANADA SP AAS, AIAA AB In this paper, definitions of degree of controllability/observability, which are defined based on a scalar value dependent on the controllability/observability Grammian matrix, are presented for discrete-time systems. The concepts of degree of controllability/observability are applied to the actuator/sensor placement problem for thin flexible orbiting square platforms, The LQG transient time responses for several typical systems with different degrees of controllability and observability are also displayed. C1 HOWARD UNIV,DEPT MECH ENGN,WASHINGTON,DC 20059. RP EricssonJackson, AJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 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 JAN-MAR PY 1997 VL 45 IS 1 BP 73 EP 89 PG 17 WC Engineering, Aerospace SC Engineering GA YA340 UT WOS:A1997YA34000004 ER PT J AU Rowlands, DD Luthcke, SB Marshall, JA Cox, CM Williamson, RG Rowton, SC AF Rowlands, DD Luthcke, SB Marshall, JA Cox, CM Williamson, RG Rowton, SC TI Space shuttle precision orbit determination in support of SLA-1 using TDRSS and GPS tracking data SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT EGS Conference CY MAY, 1996 CL THE HAGUE, NETHERLANDS ID TOPEX/POSEIDON AB On January 11, 1996, the Space Shuttle Endeavor, mission STS-72, was launched, carrying aboard the first of four Shuttle Laser Altimeter (SLA) experiments. In support of SLA-1, precise orbits have been computed from Tracking and Data Relay Satellite System (TDRSS) Doppler observations. In some cases, these data were combined with Global Positioning System (GPS) pseudorange observations. Traditionally, the Tracking and Data Relay Satellite (TDRS) orbits themselves have been the dominant source of error in Shuttle orbit determination during quiescent attitude periods. However, a new technique utilizing TOPEX/Poseidon's (T/P) precise orbit knowledge plus the TDRSS-T/P Doppler tracking is used to significantly reduce the TDRS orbit errors. That approach, along with improved modeling and parameterization have allowed us to compute precise Shuttle orbits from TDRSS-Shuttle Doppler tracking data. Orbit overlap comparisons indicate these Doppler-derived orbits have a meter level (1 sigma) radial precision, and they agree radially with the combined Doppler and GPS derived orbits at the 1.5 m level (1 sigma). C1 HUGHES STX,GREENBELT,MD 20770. RP Rowlands, DD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Rowlands, David/D-2751-2012; Luthcke, Scott/D-6283-2012 NR 18 TC 9 Z9 9 U1 0 U2 0 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 JAN-MAR PY 1997 VL 45 IS 1 BP 113 EP 129 PG 17 WC Engineering, Aerospace SC Engineering GA YA340 UT WOS:A1997YA34000006 ER PT J AU Wingard, CD AF Wingard, CD TI Use of thermal analysis techniques for examining blow-molded PET bottle specimens SO JOURNAL OF THERMAL ANALYSIS LA English DT Article; Proceedings Paper CT Proceedings of the 11th International Congress on Thermal Analysis and Calorimetry CY AUG 12, 1996 CL N AMER THERMAL ANAL SOC, PHILADELPHIA, PA HO N AMER THERMAL ANAL SOC DE glass transition; hot-fill; initial crystallinity; shrinkage; stretch-blow-molding ID POLY(ETHYLENE-TEREPHTHALATE) AB Eight samples from different areas of stretch-blow-molded poly(ethylene terephthalate) [PET] bottles, including a PET resin control, were tested by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The glass transition temperature (T-g) was found to linearly decrease about 6 degrees C from zero to 45 percent initial crystallinity. Measurements of T-c (crystallization temperature, DSC) and film tension modulus (TMA) were related to crystallization rate during stretch-blow-molding. The TMA linear coefficients of thermal expansion and shrinkage were shown to be important for blow-molding temperature control. RP Wingard, CD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAIL CODE EH32,HUNTSVILLE,AL 35812, USA. NR 8 TC 3 Z9 3 U1 1 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0368-4466 J9 J THERM ANAL JI J. Therm. Anal. PY 1997 VL 49 IS 1 BP 385 EP 391 DI 10.1007/BF01987461 PG 7 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA XD480 UT WOS:A1997XD48000047 ER PT J AU Wingard, CD AF Wingard, CD TI Use of the TMA film tension technique for differentiating polymeric materials in the space shuttle program SO JOURNAL OF THERMAL ANALYSIS LA English DT Article; Proceedings Paper CT Proceedings of the 11th International Congress on Thermal Analysis and Calorimetry CY AUG 12, 1996 CL N AMER THERMAL ANAL SOC, PHILADELPHIA, PA HO N AMER THERMAL ANAL SOC DE accelerated aging; brown paint anomaly; RSRM segment; TMA film tension; vacuum bag material AB During the recent processing of a forward segment of the Reusable Solid Rocket Motor (RSRM) for the Space Shuttle, the topcoat white paint turned light brown after autoclave cure of the case insulation. Thermomechanical analysis (TMA) in the film tension mode produced modulus vs. temperature data that helped to explain why a certain insulation vacuum bagging material contributed to the brown paint color. TMA film tension data was also obtained on lab-created white and brown topcoat paint samples (with and without primer). The brown/white ratios of moduli were about 2/1 and 4/1 for topcoat/primer and topcoat only samples, respectively, from 25 to 55 degrees C. RP Wingard, CD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAIL CODE EH32,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0368-4466 J9 J THERM ANAL JI J. Therm. Anal. PY 1997 VL 49 IS 1 BP 393 EP 398 DI 10.1007/BF01987462 PG 6 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA XD480 UT WOS:A1997XD48000048 ER PT J AU Fought, RM Gupta, RN Lyne, JE AF Fought, RM Gupta, RN Lyne, JE TI Extension of curve fits for enthalpy of equilibrium air to 1000 atmospheres SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article C1 NASA,LANGLEY RES CTR,GAS DYNAM DIV,HAMPTON,VA 23681. UNIV TENNESSEE,DEPT MECH & AEROSP ENGN & ENGN MECH,KNOXVILLE,TN 37996. RI Lyne, James/E-6363-2011 NR 5 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 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN-MAR PY 1997 VL 11 IS 1 BP 126 EP 128 DI 10.2514/2.6213 PG 3 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA WD501 UT WOS:A1997WD50100018 ER PT J AU Sawicki, JT Capaldi, RJ Adams, ML AF Sawicki, JT Capaldi, RJ Adams, ML TI Experimental and theoretical rotordynamic characteristics of a hybrid journal bearing SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT ASME/STLE 1996 Tribology Conference CY OCT 13-17, 1996 CL SAN FRANCISCO, CA SP Amer Soc Mech Engineers, Soc Tribologists & Lubricat Engineers ID LINEARIZED ROTOR DYNAMICS; COEFFICIENTS; INSIGHTS; FLUID AB This paper describes an experimental and theoretical investigation of a four-pecker, oil-fed, orifice-compensated hydrostatic bearing including the hybrid effects of journal rotation. The test apparatus incorporates a double-spool-shaft spindle which permits independent control over the journal spin speed and the frequency of an adjustable magnitude circular orbit, for both forward and backward whirling. This configuration yields data that enables determination of the full linear anisotropic rotordynamic model. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Theoretical predictions are made for the same configuration and operating conditions as the test matrix using a finite-difference solver of Reynolds lubrication equation. The computational results agree well with test results, theoretical predictions of stiffness and damping coefficients are typically within thirty percent of the experimental results. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,DEPT AEROSP & MECH ENGN,CLEVELAND,OH 44106. RP Sawicki, JT (reprint author), CLEVELAND STATE UNIV,DEPT MECH ENGN,1983 EAST 24TH ST,CLEVELAND,OH 44115, USA. NR 34 TC 13 Z9 13 U1 1 U2 7 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD JAN PY 1997 VL 119 IS 1 BP 132 EP 141 DI 10.1115/1.2832446 PG 10 WC Engineering, Mechanical SC Engineering GA WE854 UT WOS:A1997WE85400019 ER PT J AU Boyle, RJ Ameri, AA AF Boyle, RJ Ameri, AA TI Grid orthogonality effects on predicted turbine midspan heat transfer and performance SO JOURNAL OF TURBOMACHINERY-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 FLOWS AB The effect of five different C-type grid geometries on the predicted hear transfer and aerodynamic performance of a turbine stator is examined. Predictions were obtained using two pow analysis codes, One was a finite difference analysis, and the other was a finite volume analysis. Differences among the grids in terms of heat transfer and overall performance were small. The most significant difference among the five grids occurred in the prediction of pitchwise variation in total pressure. There was consistency between results obtained with each of the pow analysis codes when the same grid was used. A grid-generating procedure in which the viscous grid is embedded within an inviscid type grid resulted in the best overall performance. C1 UNIV KANSAS,CTR RES INC,LAWRENCE,KS 66045. RP Boyle, RJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 10 Z9 10 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 1997 VL 119 IS 1 BP 31 EP 38 PG 8 WC Engineering, Mechanical SC Engineering GA WH342 UT WOS:A1997WH34200005 ER PT J AU Jennions, IK Adamczyk, JJ AF Jennions, IK Adamczyk, JJ TI Evaluation of the interaction losses in a transonic turbine HP rotor LP vane configuration SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 40th International Gas Turbine and Aeroengine Congress and Exhibition CY JUN 05-08, 1995 CL HOUSTON, TX ID SIMULATION; FLOW AB Transonic turbine rotors produce shock waves, wakes, tip leakage flows, and other secondary flows that the downstream stators have to ingest. While the physics of wake ingestion and shock interaction have been studied quite extensively, few ideas for reducing the aerodynamic interaction losses have been forthcoming. This paper aims to extend previously reported work performed by GE Aircraft Engines in. this area. It reports on both average-passage (steady) and unsteady three-dimensional numerical simulations of a candidate design to shed light on the interaction loss mechanisms and evaluate the design. The results from these simulations are first shown against rest data for a baseline configuration to engender confidence in the numerical approach. Simulations with the proposed newly designed rotor are then performed to show the trade-offs that are being made in such designs. The new rotor does improve the overall efficiency of the group and physical explanations are presented based on examining entropy production. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Jennions, IK (reprint author), GE CO,AIRCRAFT ENGINES,CINCINNATI,OH 44135, USA. NR 24 TC 19 Z9 22 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JAN PY 1997 VL 119 IS 1 BP 68 EP 76 PG 9 WC Engineering, Mechanical SC Engineering GA WH342 UT WOS:A1997WH34200009 ER PT J AU Sundaram, KB Wahid, PF Melendez, O AF Sundaram, KB Wahid, PF Melendez, O TI Deposition and x-ray photoelectron spectroscopy studies on sputtered cerium dioxide thin films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID CEO2 AB Cerium dioxide is a rare earth oxide material that can be useful in various optical and electronic applications because of its high refractive index and its dielectric constant. The purpose of this study was to conduct an x-ray photoelectron spectroscopy analysis of sputtered cerium dioxide thin films. The thin films were deposited onto glass substrates using rf magnetron sputtering. A cerium dioxide target was used and various oxygen-argon gas flow ratios under different sputtering power levels were used for deposition. The results presented here characterize the properties of the rf sputtered cerium dioxide thin films under different deposition conditions. (C) 1997 American Vacuum Society. C1 NASA,JOHN F KENNEDY SPACE CTR,MICROCHEM ANAL,DM MSL 1,KENNEDY SPACE CTR,FL 32889. RP Sundaram, KB (reprint author), UNIV CENT FLORIDA,DEPT ELECT & COMP ENGN,ORLANDO,FL 32816, USA. NR 13 TC 30 Z9 30 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JAN-FEB PY 1997 VL 15 IS 1 BP 52 EP 56 DI 10.1116/1.580475 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA WD690 UT WOS:A1997WD69000010 ER PT J AU Crassidis, JL Mook, DJ AF Crassidis, JL Mook, DJ TI Integrated estimation/identification using second-order dynamic models SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article ID IDENTIFICATION AB An algorithm is presented which accurately identifies multi-input-multi-output systems characterized by vibrating structures. More specifically, an identification technique is integrated with an optimal estimator in order to develop an algorithm which is robust with respect to measurement and process noise. The unique functional form of the integrated approach utilizes systems described by second-order models. Therefore, theoretical, mass, damping, and stiffness matrices, associated with lumped parameter models, are tailored with experimental time-domain data for system estimation and identification. This leads to an algorithm that is computationally efficient, producing realizations of complex multiple degree-of-freedom systems. The combined estimation/identification algorithm is used to identify the properties of an actual flexible truss from experimental data. Comparison of experimental frequency-domain data to the predicted model characteristics indicates that the integrated algorithm produces near-minimal realizations coupled with accurate modal properties. RP NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU ASME PI NEW YORK PA TWO PARK AVE, NEW YORK, NY 10016-5990 USA SN 1048-9002 EI 1528-8927 J9 J VIB ACOUST JI J. Vib. Acoust.-Trans. ASME PD JAN PY 1997 VL 119 IS 1 BP 1 EP 8 DI 10.1115/1.2889682 PG 8 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA WD490 UT WOS:A1997WD49000001 ER PT S AU Smith, BD Rajan, K Muscettola, N AF Smith, BD Rajan, K Muscettola, N BE Plaza, E Benjamins, R TI Knowledge acquisition for the onboard planner of an autonomous spacecraft SO KNOWLEDGE ACQUISITION, MODELING AND MANAGEMENT SE LECTURE NOTES IN ARTIFICIAL INTELLIGENCE LA English DT Article; Proceedings Paper CT 10th European Workshop on Knowledge Acquisition, Modeling and Management (EKAW'97) CY OCT 15-18, 1997 CL BARCELONA, SPAIN AB Deep Space One (DS1) will be the first spacecraft to be controlled by an autonomous closed loop system potentially capable of carrying out a complete mission with minimal commanding from Earth. A major component of the autonomous flight software is an onboard planner/scheduler. Based on generative planning and temporal reasoning technologies, the planner/scheduler transforms abstract gods into detailed tasks to be executed within resource and time limits. This paper discusses the knowledge acquisition issues involved in transitioning this novel technology into spacecraft flight software, developing the planner in the context of a large software project and completing the work under a compressed development schedule. Our experience shows that the planning framework used is adequate to address the challenges of DSI and future autonomous spacecraft systems, and it points to a series of open technological challenges in developing methodologies and tools for knowledge acquisition and validation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Smith, BD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 525-3660, Pasadena, CA 91109 USA. EM smith@aig.jpl.nasa.gov; kanna@ptolemy.arc.nasa.gov; mus@ptolemy.arc.nasa.gov NR 17 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-63592-0 J9 LECT NOTES ARTIF INT PY 1997 VL 1319 BP 253 EP 268 PG 16 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Philosophy SC Computer Science; Philosophy GA BM08E UT WOS:000077561300017 ER PT J AU Liebowitz, J Krishnamurthy, V Rodens, I Houston, C Liebowitz, A Baek, S Radko, J Zeide, J Potter, W AF Liebowitz, J Krishnamurthy, V Rodens, I Houston, C Liebowitz, A Baek, S Radko, J Zeide, J Potter, W TI Experiences in managing an expert systems project SO KYBERNETES LA English DT Article DE artificial intelligence; expert systems; project management; scheduling AB Describes some of the authors' experiences in managing a two-year expert scheduling system project called GUESS (Generically Used Expert Scheduling System), developed for NASA. Many expert systems are technical successes, but technology transfer failures. Part of the reason that some expert system projects fail is due to management issues. First discusses the GUESS project and then highlights some lessons learned on managing an expert systems project based on the GUESS experience. C1 AMER MINOR ENGN CORP,KENSINGTON,MD. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Liebowitz, J (reprint author), GEORGE WASHINGTON UNIV,DEPT MANAGEMENT SCI,WASHINGTON,DC 20052, USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU MCB UNIV PRESS LTD PI BRADFORD PA 60/62 TOLLER LANE, BRADFORD, W YORKSHIRE, ENGLAND BD8 9BY SN 0368-492X J9 KYBERNETES JI Kybernetes PY 1997 VL 26 IS 1 BP 68 EP & DI 10.1108/03684929710158124 PG 8 WC Computer Science, Cybernetics SC Computer Science GA WM706 UT WOS:A1997WM70600006 ER PT S AU Degnan, JJ McGarry, JF AF Degnan, JJ McGarry, JF BE Schreiber, U Werner, C TI SLR2000: Eyesafe and autonomous single photoelectron satellite laser ranging at kilohertz rates SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques CY SEP 24-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE laser ranging; microlasers; laser altimetry; lidar; single photon detection; meteorological instrumentation; satellites; autonomous instruments AB SLR2000 is an autonomous and eyesafesatellite laser ranging station with an expected single shot range precision of about one centimeter and a normal point precision better than 3 mm. The system will provide continuous 24 hour tracking coverage. Replication costs are expected to be roughly an order of magnitude less than current operational systems, and the system will be about 75% less er;pensive to operate and maintain relative to the manned systems. Computer simulations have predicted a daylight tracking capability to GPS and lower satellites with telescope apertures of 40 cm and have demonstrated the ability of our current autotracking algorithm to extract mean signal strengths as small as 0.0001 photoelectrons per pulse from background noise. The dominant cost driver in present SLR systems is the onsite and central infrastructure manpower required to operate the system, to service and maintain the complex subsystems (most notably the laser and high precision timing electronics), and to ensure that the transmitted laser beam is not a hazard to onsite personnel or to overflying aircraft. In designing the SLR2000 system, preference was given to simple hardware over complex, to commercially available hardware over custom, and to passive techniques over active resulting in the prototype design described here. This general approach should allow long intervals between maintenance visits and the "outsourcing" of key central engineering functions on an "as needed" basis. As a result, many of the signal extraction techniques and engineering designs employed here may have application in remotely operated or even spaceborne lidar applications. SLR2000 consists of seven major subsystems: (1) Time and Frequency Reference Unit; (2) Optical Subsystem; (3) Tracking Mount; (4) Correlation Range Receiver; (5) Meteorological Station; (6) Environmental Shelter with Azimuth Tracking Dome; and (7) System Controller. The Optical Subsystem in turn consists of a 40 cm aperture telescope and associated transmit/receive optics, a passively Q-switched microlaser operating at 2 KHz with a transmitted single pulse energy of 135 mu J, a start detector, a quadrant stop detector for simultaneous ranging and subarcsecond angle tracking, a CCD camera for automated star calibrations, and spectral and spatial filters to reduce the daylight background noise. The meteorological station includes sensors for surface pressure, temperature, relative humidity, wind speed and direction, precipitation type and accumulation, visibility, and cloud cover. The system operator is replaced by a software package called the "pseudo-operator" which, using a variety of sensor inputs: makes all of the critical operational decisions formerly made by onsite personnel. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Degnan, JJ (reprint author), NASA, Goddard Space Flight Ctr, Code 920-3, Greenbelt, MD 20771 USA. RI McGarry, Jan/C-4109-2013 NR 0 TC 13 Z9 13 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2650-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3218 BP 63 EP 77 DI 10.1117/12.295646 PG 15 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BK34S UT WOS:000071861700008 ER PT S AU Degnan, JJ AF Degnan, JJ BE Schreiber, U Werner, C TI Satellite laser ranging: scientific and technological challenges for the new millennium SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques CY SEP 24-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE laser ranging artificial satellites; lunar ranging; interplanetary ranging; reference frames; gravity; tectonics; oceanography; sea level; ice mass; automation; time transfer; laser transponders; global change AB Since its first successful demonstration in 1963, the precision of Satellite Laser Ranging (SLR) has improved by three orders of magnitude, i.e. from a few meters to a few mm. Each technological improvement has been rapidly followed by a new scientific capability. To date,centimeter accuracy SLR measurements to the passive LAGEOS satellites by a groundbased network of approximately 40 stations have : (1) helped to define a Terrestrial Reference Frame accurate to a centimeter globally; (2) measured the motions of tectonic plates and detected regional crustal deformations near the plate boundaries; (3) helped define the terrestrial gravity field, and (4) monitored variations in the Earth's gravity field, the orientation of the Earth's spin axis, and its rate of rotation and related them to angular momentum exchanges and/or large mass redistributions within the land, ocean, atmosphere system. By providing few centimeter precision orbits measurements to altimetric satellites such as ERS-1 and 2 and TOPEX/POSEIDON, SLR has enabled precise measurements of global ocean circulation, wave heights, ice topography, and even mean sea level rises on the order of two mm/yr. In addition to providing useful tests of General Relativity, centimeter accuracy SLR measurements to five retroreflector packages placed on the lunar surface by US and Soviet landers have helped to define the planetary reference frame, provided ultraprecise lunar ephemerides, defined the lunar librations, and constrained models of the Moon's internal structure. As we enter the new millennium, there are three principal technology thrusts evident in the SLR community (1) the improvement of range absolute accuracy by another order of magnitude through the use of multiwavelength techniques, picosecond timing, and improved satellite targets; (2) the development of highly automated, eyesafe ground systems for safer and more cost-effective operations; and (3) extending the range of SER beyond the Moon to the inner planets through the use of asynchronous laser transponders. New applications emerging for SLR include: the demonstration of routine global lime transfer to better than 50 psec; the synergistic combination of SLR, GPS, laser altimetry and perhaps synthetic aperture radar (SAR) to achieve millimeter accuracy sea surface and ice topography; the determination of time variations in low order tesseral harmonics of the gravity field and their interpretation in terms of global change; and the use of laser transponders for planetary relation and dynamical studies (precession, polar motion. length of day) improved planetary orbital ephemerides, solar system dynamics, solar structure and dynamics, general relativity, and planetary atmosphere/solid body interactions. C1 NASA, Goddard Space Flight Ctr, Geosci Technol Off, Greenbelt, MD 20771 USA. RP Degnan, JJ (reprint author), NASA, Goddard Space Flight Ctr, Geosci Technol Off, Code 920-3, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 2 U2 6 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2650-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3218 BP 80 EP 91 DI 10.1117/12.295655 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BK34S UT WOS:000071861700009 ER PT S AU Zagwodzki, TW McGarry, JF Degnan, JJ Varghese, T AF Zagwodzki, TW McGarry, JF Degnan, JJ Varghese, T BE Schreiber, U Werner, C TI Two-color SLR experiments at the GSFC 1.2m telescope SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques CY SEP 24-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE satellite laser ranging; two color; streak camera AB Satellite range measurements which include differential time of flight measurement between simultaneous doubled and tripled Nd:YAG laser pulses are being made at the NASA/Goddard Space might Center's 1.2m Telescope Tracking Facility. A description of the streak camera-based range receiver is given along with the differential time of flight measurement. Typical streak camera return waveforms are displayed from satellite tracks which include: ADEOS/RIS, AJISAI, GFZ-1, STELLA, and TOPEX. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zagwodzki, TW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI McGarry, Jan/C-4109-2013 NR 0 TC 4 Z9 4 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2650-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3218 BP 113 EP 124 DI 10.1117/12.295660 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BK34S UT WOS:000071861700012 ER PT S AU Winker, DM AF Winker, DM BE Schreiber, U Werner, C TI Space lidar mission concepts for climate studies SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques CY SEP 24-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE lidar; aerosols; clouds; climate AB Clouds and aerosols affect the magnitude of radiative fluxes at the Earth's surface and within the atmosphere through the scattering and absorption of incoming solar and outgoing thermal radiation. Through these mechanisms they have important influences on the climate and remote sensing from space is required to assess their effects on a global scale. Current capabilities to observe clouds and aerosols using passive satellite sensors are limited, however. The Lidar In-space Technology Experiment, Clown on the space shuttle in September 1994, demonstrated the application of space lidar to the study ni clouds and aerosols. Lidar technology has now matured to a point where satellite lidars with on-orbit lifetimes of several years are feasible. Space lidar will provide vertically resolved measurements of the distribution of clouds and aerosols as well as optical and microphysical properties, allowing improved characterization of the role of aerosol and cloud in global climate. This paper will discuss the application of cloud/aerosol satellite lidars to the climate problem. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winker, DM (reprint author), NASA, Langley Res Ctr, MS-475, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2650-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3218 BP 126 EP 130 DI 10.1117/12.295647 PG 5 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BK34S UT WOS:000071861700013 ER PT S AU Winker, DM AF Winker, DM BE Schreiber, U Werner, C TI LITE: Results, performance characteristics, and data archive SO LASER RADAR RANGING AND ATMOSPHERIC LIDAR TECHNIQUES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Radar Ranging and Atmospheric Lidar Techniques CY SEP 24-26, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE lidar; LITE; aerosols; clouds climate AB The Lidar In-space Technology Experiment (LITE) is a three-wavelength backscatter lidar which was flown on Space Shuttle mission STS-54 in September 1994. Observations of clouds and aerosols were acquired between 57 degrees N and 57 degrees S on 10 days of the mission. LITE provides a dataset with which to explore the applications of space lidar and to begin to develop and demonstrate the retrieval algorithms required for future space lidars. Results from a number of science investigations using LITE data will ba discussed to illustrate system performance characteristics and capabilities. A LlTE Level I data product is being created and will be made available through the NASA Langley Distributed Active Archive Center (DAAC). C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winker, DM (reprint author), NASA, Langley Res Ctr, MS-475, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2650-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3218 BP 186 EP 193 DI 10.1117/12.295639 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BK34S UT WOS:000071861700021 ER PT B AU DeCoursey, RJ Poole, LR Hostetler, CA Kent, G Hansen, G AF DeCoursey, RJ Poole, LR Hostetler, CA Kent, G Hansen, G BE Kamerman, GW TI Aircraft exhaust particle measurement with multiple ground based lidar systems SO LASER RADAR TECHNOLOGY AND APPLICATIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Technology and Applications II CY APR 23-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE lidar; remote sensing; vortex AB Recently NASA Langley Research Center's (LaRC) Aerosol Research Branch conducted an aircraft exhaust particle experiment involving two ground based lidar systems and NASA's B737-100, T39 and OV10 aircraft. The experiment took place at LaRC in February and March of 1996. During flight, exhaust particles exiting the two wing-mounted engines of the B737 become quickly entrained into the aircraft's wingtip vortices. The LaRC lidar systems were used to measure the distribution and optical properties of these exhaust particles as the B737 overflew the lidar facility. Two lidar systems, located in a common facility, were utilized for this experiment. One system was a fixed zenith-viewing lidar with a 48-inch receiver and a 2 J transmitter, and the second was a scanning lidar with a 14-inch receiver and a 600 mi transmitter. Two measurement geometries were employed for the experiment. In the first geometry, the B737 flew upwind of the lidar facility and perpendicular to the ambient wind. The second design had the aircraft fly directly over the facility, and parallel to the ambient wind. Under either scenario data were acquired at 20 and 30 Hertz, by the fixed zenith and scanning system respectively, as the ambient wind carried the vortex pair across the field of view of the lidars. The two supporting aircraft (the T39 and OV10) were used to collect in-situ particle data and to measure atmospheric turbulence, respectively. In this paper all aspects of the experiment will be discussed including the lidar systems, the geometry of the experiment, and the aircraft used. Also, selected data obtained during the experiment will be presented. RP DeCoursey, RJ (reprint author), NASA,LANGLEY RES CTR,SCI APPLICAT INT CORP,MS 417,HAMPTON,VA 23681, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2480-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3065 BP 9 EP 20 DI 10.1117/12.281005 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BJ51D UT WOS:A1997BJ51D00002 ER PT B AU Howard, RT Bryan, TC Book, ML Jackson, JL AF Howard, RT Bryan, TC Book, ML Jackson, JL BE Kamerman, GW TI Active sensor system for automatic rendezvous and docking SO LASER RADAR TECHNOLOGY AND APPLICATIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Technology and Applications II CY APR 23-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE video sensor; relative navigation; automatic rendezvous and docking; automatic rendezvous and capture AB NASA's Marshall Space Flight Center has developed an active sensor system, the Video Guidance Sensor (VGS), to provide near-range relative position and attitude data. The VGS will be part of an automatic rendezvous and docking system. The VGS determines the relative positions and attitudes (in all six degrees-of-freedom) between the active sensor and the passive target. It works by using laser diodes to illuminate the retro-reflectors in the target, a solid-state camera to detect the return from the target retro-reflectors, and a frame grabber and digital signal processor to convert the video information into relative positions and attitudes. The current sensor design is the result of several years of development and testing, and it is being built to fly as an experiment payload on the Space Shuttle. The VGS system is designed to operate with the target completely visible within a relative azimuth of +/-10.5 degrees and a relative elevation of +/-8 degrees. The system will acquire and track the target within that field-of-view anywhere from 1.0 meters to 110 meters range at any relative roll angle and relative pitch and yaw attitudes of up to +/-10 degrees. The data is output from the sensor at 5 Hz, and the target and sensor software have been designed to permit two independent sensors to operate simultaneously for redundancy. RP Howard, RT (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,EB44,HUNTSVILLE,AL 35812, USA. NR 0 TC 4 Z9 4 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2480-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3065 BP 106 EP 115 DI 10.1117/12.281001 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BJ51D UT WOS:A1997BJ51D00011 ER PT B AU Howard, RT Cole, HJ Jackson, JL Kamerman, GW Fronek, D AF Howard, RT Cole, HJ Jackson, JL Kamerman, GW Fronek, D BE Kamerman, GW TI Automatic rendezvous and docking system test and evaluation SO LASER RADAR TECHNOLOGY AND APPLICATIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Laser Technology and Applications II CY APR 23-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE video sensor; automatic rendezvous and docking; automatic rendezvous and capture; relative navigation; radiometry; range measurement; laser tracking; laser radar AB The Video Guidance Sensor is a key element of an automatic rendezvous and docking program administered by NASA. The system uses laser illumination of a passive target in the field of view of an on-board camera and processes the video image to determine the relative position and attitude between the target and the sensor. Theoretical predictions and evaluations, and laboratory measurements and tests are presented for the lasers, target components, camera system, signal processor, and a solar simulator. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP Jackson, JL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MS EB44,HUNTSVILLE,AL 35812, USA. NR 0 TC 2 Z9 3 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2480-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3065 BP 131 EP 139 DI 10.1117/12.281002 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BJ51D UT WOS:A1997BJ51D00013 ER PT B AU Beyerle, G Schafer, HJ Schrems, O Neuber, R Rairoux, P McDermid, IS AF Beyerle, G Schafer, HJ Schrems, O Neuber, R Rairoux, P McDermid, IS BE Wolf, JP TI Lidar observations of tropical high-altitude cirrus clouds: Results from dual wavelength Raman lidar measurements during the ALBATROSS campaign 1996 SO LIDAR ATMOSPHERIC MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Atmospheric Monitoring CY JUN 16-18, 1997 CL MUNICH, GERMANY SP Deut Forschungsanstalt Luftfahrt & Raumfahrt, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE Raman lidar; aerosols; cirrus clouds AB Results from dual wavelength Raman lidar observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus clouds were present in more than 50% of the observations at latitudes between 23.5 degrees S and 23.5 degrees N and altitudes between 11 and 16 km. Volume depolarization is found to be a sensitive parameter for the detection of subvisible cloud layers. Using Mie scattering calculations estimates of the ice water content are derived. RP Beyerle, G (reprint author), CALTECH,JET PROP LAB,WRIGHTWOOD,CA 92397, USA. OI Beyerle, Georg/0000-0003-1215-2418 NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2525-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3104 BP 43 EP 46 DI 10.1117/12.275163 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BH98E UT WOS:A1997BH98E00006 ER PT B AU Singh, UN WilliamsByrd, JA Barnes, NP Yu, JR Petros, M Lockard, GE Modlin, EA AF Singh, UN WilliamsByrd, JA Barnes, NP Yu, JR Petros, M Lockard, GE Modlin, EA BE Wolf, JP TI Diode-pumped 2-mu m solid state lidar transmitter for wind measurements SO LIDAR ATMOSPHERIC MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Lidar Atmospheric Monitoring CY JUN 16-18, 1997 CL MUNICH, GERMANY SP Deut Forschungsanstalt Luftfahrt & Raumfahrt, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE coherent wind lidar; Ho:Tm:YLF laser; diode-pumped solid-state laser; eye-safe two micron laser; optical amplifiers; rare earth and transition metal solid state lasers; diode laser arrays; lidar AB Laser remote sensing technique using coherent lidar systems are being widely used for wind measurements, Laser wind measurements use the Doppler shift of backscattered radiation to determine the wind speed. To measure the small Doppler shifts accurately heterodyne detection is used. This technique requires an energetic, low divergence, narrow linewidth laser transmitter to maintain a high degree of coherence. For measurements from ground, air, or space platform, a reliable, all solid-state laser transmitter in the eye-safe region with appreciable energy/pulse is required. This paper reports development and performance of a diode-pumped solid-state amplifiers at 2-micrometer. Q-switched, 400-ns pulses with output energy of 700 ml at 2-mu m, representing an optical-to-optical efficiency of 2%, was achieved from five diode-pumped Ho:Tm:YLF laser amplifiers at room-temperature. RP Singh, UN (reprint author), NASA,LANGLEY RES CTR,REMOTE SENSING TECHNOL BRANCH,MS 474,HAMPTON,VA 23681, USA. NR 0 TC 7 Z9 7 U1 2 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2525-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3104 BP 173 EP 178 DI 10.1117/12.275147 PG 6 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BH98E UT WOS:A1997BH98E00022 ER PT S AU Bernstein, MP Allamandola, LJ Sandford, SA AF Bernstein, MP Allamandola, LJ Sandford, SA BE Raulin, F Greenberg, JM TI Complex organics in laboratory simulations of interstellar/cometary ices SO LIFE SCIENCES: COMPLEX ORGANICS IN SPACE SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3-2 Symposium of COSPAR Scientific Commission F on Life Sciences - Complex Organics in Space, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Int Soc Study Origin Life, Sci Commiss B, Univ Paris 12 ID TIME-DEPENDENT CHEMISTRY; DENSE MOLECULAR CLOUDS; INFRARED-SPECTROSCOPY; CRYOGENIC TEMPERATURES; ASTROPHYSICAL ICES; MICRON ABSORPTION; GRAIN MANTLES; SOLID CO; ANALOGS; FORMALDEHYDE AB We present the photochemical and thermal evolution of both non-polar and polar ices representative of interstellar and pre-cometary grains. Ultraviolet photolysis of the non-polar ices comprised of O-2, N-2, and CO produces CO2, N2O, O-3, CO3, HCO, H2CO, and possibly NO and NO2. When polar ice analogs (comprised of H2O, CH3OH, CO, and NH3) are exposed to UV radiation, simple molecules are formed including: H-2, H2CO, CO2, CO, CH4, and HCO. (the formyl radical). Warming produces moderately complex species such as CH3CH2OH (ethanol), HC(=O)NH2 (formamide), CH3C(=O)NH2 (acetamide), R-CN and/or R-NC (nitriles and/or isonitriles). Several of these are already known to be in the interstellar medium, and their presence indicates the importance of grain processing. Infrared spectroscopy, H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry demonstrate that after warming to room temperature what remains is an organic residue composed primarily of hexamethylenetetramine (HMT, C6H12N4) and other complex organics including the amides above and polyoxymethylene (POM) and its derivatives. The formation of these organic species from simple starting mixtures under conditions germane to astrochemistry may have important implications for the organic chemistry of interstellar ice grains, comets and the origins of life. (C) 1997 COSPAR. Published by Elsevier Science Ltd. RP Bernstein, MP (reprint author), NASA, AMES RES CTR, MS 245-6, MOFFETT FIELD, CA 94035 USA. NR 37 TC 35 Z9 36 U1 1 U2 22 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043108-9 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 7 BP 991 EP 998 DI 10.1016/S0273-1177(97)00340-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Chemistry, Organic; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Chemistry; Geology; Meteorology & Atmospheric Sciences GA BJ08F UT WOS:A1997BJ08F00002 PM 11541346 ER PT S AU Hudgins, DM Allamandola, LJ Sandford, SA AF Hudgins, DM Allamandola, LJ Sandford, SA BE Raulin, F Greenberg, JM TI Complex organic molecules in space: The carriers of the interstellar infrared emission features SO LIFE SCIENCES: COMPLEX ORGANICS IN SPACE SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3-2 Symposium of COSPAR Scientific Commission F on Life Sciences - Complex Organics in Space, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Int Soc Study Origin Life, Sci Commiss B, Univ Paris 12 ID AROMATIC HYDROCARBON CATIONS; MATRIX-ISOLATED NAPHTHALENE; CARBONACEOUS COMPOSITE QCC; ELECTRONIC-SPECTRA; BANDS; SPECTROSCOPY; IDENTIFICATION; ANTHRACENE; TETRACENE; PENTACENE AB The Unidentified Infrared Bands (UIR bands) are a complex family of infrared emission features which are observed in a variety of astronomical sources. While these features have been known for more than twenty years, a satisfactory identification of the carriers remains elusive. While the gross appearance of the emission spectrum indicates that the molecular carriers are aromatic compounds, differences in detail between the astronomical spectra and the available laboratory spectra have prevented a more complete description of the identity and physical state of these compounds. In this paper we present the first detailed comparison between the astronomical emission spectra and the spectra of ionized polycyclic aromatic hydrocarbons (PAHs) measured in the laboratory. These spectra are found to provide the best fit to date of the astronomical spectra and demonstrate that the positions and intensities of the UIR bands are entirely consistent with the emission from a gas-phase mixture of PAH molecules dominated by PAH cations. (C) 1997 COSPAR. Published by Elsevier Science Ltd. RP Hudgins, DM (reprint author), NASA, AMES RES CTR, MS 245-6, MOFFETT FIELD, CA 94035 USA. NR 26 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043108-9 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 7 BP 999 EP 1008 DI 10.1016/S0273-1177(97)00341-4 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Chemistry, Organic; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Chemistry; Geology; Meteorology & Atmospheric Sciences GA BJ08F UT WOS:A1997BJ08F00003 PM 11541347 ER PT S AU Trotman, AA David, PP Bonsi, CK Hill, WA Mortley, DG Loretan, PA AF Trotman, AA David, PP Bonsi, CK Hill, WA Mortley, DG Loretan, PA BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Integrating biological treatment of crop residue into a hydroponic sweetpotato culture SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB Residual biomass from hydroponic culture of sweetpotato [Ipomoea batatas (L.) Lam.] was degraded using natural bacterial soil isolates. Sweetpotato was grown for 120 days in hydroponic culture with a nutrient solution comprised of a ratio of 80% modified half Hoagland solution to 20% filtered effluent from an aerobic starch hydrolysis bioreactor. The phytotoxicity of the effluent was assayed with 'Waldmann's Green' lettuce (Lactuca sativa L.) and the ratio selected after a 60-day bioassay using sweetpotato plants propagated vegetatively from cuttings. Controlled environment chamber experiments were conducted to investigate the impact of filtrate from biological treatment of crop residue on growth and storage root production with plants grown in a modified half Hoagland solution. Incorporation of bioreactor effluent, reduced storage root yield of 'Georgia Jet' sweetpotato but the decrease was not statistically significant when compared with yield for plants cultured in a modified half Hoagland solution without filtrate. However, yield of 'TU-82-155' sweetpotato was significantly reduced when grown in a modified half Hoagland solution into which filtered effluent had been incorporated. Total biomass was significantly reduced for both sweetpotato cultivars when grown in bioreactor effluent. The leaf area and dry matter accumulation were significantly (P < 0.05) reduced for both cultivars when grown in solution culture containing 20% filtered effluent. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Tuskegee Univ, NASA, Ctr CELSS, Tuskegee, AL 36088 USA. RP Trotman, AA (reprint author), Tuskegee Univ, NASA, Ctr CELSS, Tuskegee, AL 36088 USA. FU CSAP SAMHSA HHS [ALX-SP-1D] NR 9 TC 1 Z9 1 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1805 EP 1813 DI 10.1016/S0273-1177(97)00845-4 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900002 PM 11542554 ER PT S AU Mackowiak, CL Wheeler, RM Stutte, GW Yorio, NC Sager, JC AF Mackowiak, CL Wheeler, RM Stutte, GW Yorio, NC Sager, JC BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Use of biologically reclaimed minerals for continuous hydroponic potato production in a CELSS SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB Plant-derived nutrients were successfully recycled in a Controlled Ecological Life Support System (CELSS) using biological methods. The majority of the essential nutrients were recovered by microbiologically treating the plant biomass in an aerobic bioreactor. Liquid effluent containing the nutrients was then returned to the biomass production component via a recirculating hydroponic system. Potato (Salonum tuberosum L.) cv. Norland plants were grown on those nutrients in either a batch production mode (same age plants on a nutrient solution) or a staggered production mode (4 different ages of plants on a nutrient solution). The study continued over a period of 418 days, within NASA Breadboard Project's Biomass Production Chamber at the Kennedy Space Center. During this period, four consecutive batch cycles (104-day harvests) and 13 consecutive staggered cycles (26-day harvests) were completed using reclaimed minerals and compared to plants grown with standard nutrient solutions. All nutrient solutions were continually recirculated during the entire 418 day study. In general, tuber yields with reclaimed minerals were within 10% of control solutions. Contaminants, such as sodium and recalcitrant organics tended to increase over time in solutions containing reclaimed minerals, however tuber composition was comparable to tubers grown in the control solutions. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. NASA, Biomed Operat & Res Off, Kennedy Space Ctr, FL 32899 USA. RP Mackowiak, CL (reprint author), Dynamac Corp, Mail Code Dyn-3, Kennedy Space Ctr, FL 32899 USA. NR 20 TC 5 Z9 5 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1815 EP 1820 DI 10.1016/S0273-1177(97)00846-6 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900003 PM 11542555 ER PT S AU Wignarajah, K Bubenheim, DL AF Wignarajah, K Bubenheim, DL BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Integration of crop production with CELSS waste management SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID RESOURCE RECOVERY AB Lettuce plants were grown utilizing water, inorganic elements, and CO2 inputs recovered from waste streams. The impact of these waste-derived inputs on the growth of lettuce was quantified and compared with results obtained when reagent grade inputs were used. Phytotoxicity was evident in both the untreated wastewater stream and the recovered CO2 stream, The toxicity of surfactants in wastewater was removed using several treatment systems, Harmful effects of gaseous products resulting from incineration of inedible biomass on crop growth were observed. No phytotoxicity was observed when inorganic elements recovered from incinerated biomass ash were used to prepare the hydroponic solution, but the balance of nutrients had to be modified to achieve near optimal growth. The results were used to evaluate closure potential of water and inorganic elemental loops for integrated plant growth and human requirements. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Lockheed Martin Engn & Sci Corp, Ames Res Ctr, Space Technol Div,Regenerat Life Support Branch, Moffett Field, CA 94035 USA. RP Wignarajah, K (reprint author), NASA, Lockheed Martin Engn & Sci Corp, Ames Res Ctr, Space Technol Div,Regenerat Life Support Branch, Mail Stop 239A-3, Moffett Field, CA 94035 USA. NR 23 TC 6 Z9 6 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1833 EP 1843 DI 10.1016/S0273-1177(97)00849-1 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900006 PM 11542558 ER PT S AU Bubenheim, DL Patterson, M Wignarajah, K Flynn, M AF Bubenheim, DL Patterson, M Wignarajah, K Flynn, M BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Incineration of biomass and utilization of product gas as a CO2 source for crop production in closed systems: Gas quality and phytotoxicity SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID RESOURCE RECOVERY; PLANTS; AIR; LEAVES; NO2 AB This study addressed the recycle of carbon from inedible biomass to CO2 for utilization in crop production. Earlier work identified incineration as an attractive approach to resource recovery from solid wastes because the products are well segregated. Given the effective separation of carbon into the gaseous product stream from the incinerator in the form of CO2 we captured the gaseous stream produced during incineration of wheat inedible biomass and utilized it as the CO2 source for crop production. Injection rate was based on maintenance of CO2 concentration in the growing environment. The crop grown in the closed system was lettuce. Carbon was primarily in the form of CO2 in the incinerator product gas with less than 8% of carbon compounds appearing as CO. Nitrogen oxides and organic compounds such as toluene, xylene, and benzene were present in the product gas at lower concentrations (<4 mu mol mol(-1)); sulfur containing compounds were below the detection limits. Direct utilization of the gaseous product of the incinerator as the CO2 source was toxic to lettuce grown in a closed chamber. Net photosynthetic rates of the crop was suppressed more than 50% and visual injury symptoms were visible within 3 days of the introduction of the incinerator gas. Even the removal of the incinerator gas after two days of crop exposure and replacement with pure CO2 did not eliminate the toxic effects. Both organic and inorganic components of the incinerator gas are candidates for the toxin. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Ames Res Ctr, Space Technol Div, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. Lockheed Martin Engn & Sci Corp, Ames Res Ctr, Space Technol Div, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. RP Bubenheim, DL (reprint author), NASA, Ames Res Ctr, Space Technol Div, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. NR 22 TC 3 Z9 3 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1845 EP 1850 DI 10.1016/S0273-1177(97)00850-8 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900007 PM 11542559 ER PT S AU Stutte, GW Mackowiak, CL Yorio, NC Wheeler, RM AF Stutte, GW Mackowiak, CL Yorio, NC Wheeler, RM BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Theoretical and practical considerations for staggered production of crops in a BLSS SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB A functional Bioregenerative Life Support System (BLSS) will generate oxygen, remove excess carbon dioxide, purify water, and produce food on a continuous basis for long periods of operation. In order to minimize fluctuations in gas exchange, water purification, and yield that are inherent in batch systems, staggered planting and harvesting of the crop is desirable. A 418-d test of staggered production of potato cv. Norland (26-d harvest cycles) using nutrients recovered from inedible biomass was recently completed at Kennedy Space Center. The results indicate that staggered production can be sustained without detrimental effects on life support functions in a CELSS. System yields of H2O, O-2 and food were higher in staggered than batch plantings. Plants growing in staggered production or batch production on "aged" solution initiated tubers earlier, and were shorter than plants grown on "fresh" solution. This morphological response required an increase in planting density to maintain full canopy coverage. Plants grown in staggered production used available light more efficiently than the batch planting due to increased sidelighting. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. NASA, Biomed Operat & Res Off, Kennedy Space Ctr, FL 32899 USA. RP Stutte, GW (reprint author), Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. NR 5 TC 5 Z9 5 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1851 EP 1854 DI 10.1016/S0273-1177(97)00851-X PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900008 PM 11542560 ER PT S AU Chun, C Mitchell, CA AF Chun, C Mitchell, CA BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Dynamic optimization of CELSS crop photosynthetic rate by computer-assisted feedback control SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID GAS-EXCHANGE AB A procedure for dynamic optimization of net photosynthetic rate (Pn) for crop production in Controlled Ecological Life-Support Systems (CELSS) was developed using leaf lettuce as a model crop. Canopy Pn was measured in real time and fed back for environmental control. Setpoints of photosynthetic photon nux (PPF) and CO2 concentration for each hour of the crop-growth cycle were decided by computer to reach a targeted Pn each day. Decision making was based on empirical mathematical models combined with rule sets developed from recent experimental data. Comparisons showed that dynamic control resulted in better yield per unit energy input to the growth system than did static control. With comparable productivity parameters and potential for significant energy savings, dynamic control strategies will contribute greatly to the sustainability of space-deployed CELSS. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Purdue Univ, NASA, Specialized Ctr Res & Training Bioregenerat Life, W Lafayette, IN 47907 USA. RP Chun, C (reprint author), Purdue Univ, NASA, Specialized Ctr Res & Training Bioregenerat Life, W Lafayette, IN 47907 USA. NR 9 TC 0 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1855 EP 1860 DI 10.1016/S0273-1177(97)00852-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900009 PM 11542561 ER PT S AU Corey, KA Barta, DJ Edeen, MA Henninger, DL AF Corey, KA Barta, DJ Edeen, MA Henninger, DL BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Atmospheric leakage and method for measurement of gas exchange rates of a crop stand at reduced pressure SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID CONTROLLED-ENVIRONMENT; CHAMBERS AB The variable pressure growth chamber (VPGC) was used in a 34-day functional test to grow a wheat crop using reduced pressure (70 kPa) episodes totalling 131 hours. Primary goals of the test were to verify facility and subsystem performance at 70 kPa and to determine responses of a wheat stand to reduced pressure and modified partial pressures of carbon dioxide and oxygen. Operation and maintenance of the chamber at 70 kPa involved continuous evacuation of the chamber atmosphere, leading to CO2 influx and efflux. A model for calculating CO2-exchange rates (net photosynthesis and dark respiration) was developed and tested and involved measurements of chamber leakage to determine appropriate corrections. Measurement of chamber leakage was based on the rate of pressure change over a small pressure increment (70.3 to 72.3 kPa) with the pump disabled. Leakage values were used to correct decreases and increases in chamber CO2 concentration resulting from net photosynthesis (Ps) and dark respiration (DR), respectively. Composite leakage corrections (influx and efflux) at day 7 of the test were 9 % and 19 % of the changes measured for Ps and DR, respectively. On day 33, composite corrections were only 3 % for Ps and 4 % for DR. During the test, the chamber became progressively tighter; the leak rate at 70.3 kPa decreasing from 2.36 chamber volumes/day pretest, to 1.71 volumes/day at the beginning of the test, and 1.16 volumes/day at the end of the test. Verification of the short-term leakage tests (rate of pressure rise) were made by testing CO2 leakage with the vacuum pump enabled and disabled. Results demonstrate the suitability of the VPGC for conducting gas exchange measurements of a crop stand at reduced pressure. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Univ Massachusetts, Dept Plant & Soil Sci, Amherst, MA 01003 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Corey, KA (reprint author), Univ Massachusetts, Dept Plant & Soil Sci, Amherst, MA 01003 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1861 EP 1867 DI 10.1016/S0273-1177(97)87952-5 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900010 PM 11542562 ER PT S AU Corey, KA Barta, DJ Henninger, DL AF Corey, KA Barta, DJ Henninger, DL BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Photosynthesis and respiration of a wheat stand at reduced atmospheric pressure and reduced oxygen SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID CARBON-DIOXIDE; ENVIRONMENTS; EXCHANGE AB A 34-day functional test was conducted in Johnson Space Center's Variable Pressure Growth Chamber (VPGC) to determine responses of a wheat stand to reduced pressure (70 kPa) and modified partial pressures of carbon dioxide and oxygen. Reduced pressure episodes were generally six to seven hours in duration, were conducted at reduced ppO(2) (14.7 kPa), and were interrupted with longer durations of ambient pressure (101 kPa). Daily measurements of stand net photosynthesis (Pn) and dark respiration (DR) were made at both pressures using a ppCO(2) of 121 Pa. Corrections derived from leakage tests were applied to reduced pressure measurements. Rates of Pn at reduced pressure averaged over the complete test were 14.6 % higher than at ambient pressure, but rates of DR were unaffected. Further reductions in ppO(2) were achieved with a molecular sieve and were used to determine if Pn was enhanced by lowered O-2 or by lowered pressure. Decreased ppO(2) resulted in enhanced rates of Pn, regardless of pressure, but the actual response was dependent on the ratio of ppO(2)/ppCO(2). Over the range of ppO(2)/ppCO(2) of 80 to 200, the rate of Pn declined linearly. Rate of DR was unaffected over the same range and by dissolved O-2 levels down to 3.1 ppm, suggesting that normal rhizosphere and canopy respiration occur at atmospheric ppO(2) levels as low as 11 kPa. Partial separation of effects attributable to oxygen and those related to reduced pressure (e.g. enhanced diffusion of CO2) was achieved from analysis of a CO2 drawdown experiment. Results will be used for design and implementation of studies involving complete crop growth tests at reduced pressure. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Univ Massachusetts, Dept Plant & Soil Sci, Amherst, MA 01003 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Corey, KA (reprint author), Univ Massachusetts, Dept Plant & Soil Sci, Amherst, MA 01003 USA. NR 29 TC 10 Z9 12 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1869 EP 1877 DI 10.1016/S0273-1177(97)00854-5 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900011 PM 11542563 ER PT S AU Mortley, DG Loretan, PA Hill, JH Seminara, J AF Mortley, DG Loretan, PA Hill, JH Seminara, J BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI CO2 enrichment influences yields of 'Florunner,' 'Georgia Red' and 'New Mexico' peanut cultivars SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB Three peanut cultivars, 'Florunner,' 'Georgia Red,' and 'New Mexico,' were grown in reach-in chambers to determine response to CO2 enrichment. CO2 treatments were ambient (400 mu mol mol(-1)) and 700 mu mol mol(-1). Growth chamber conditions included 700 mu mol m(-2) s(-1) photosynthetic photon flux (PPF), 28/22C, 70% RH, and 12/12 h photoperiod. Growth media consisted of a 1:1 mixture (v/v) of vermiculite and sterilized sand. Six 10 L pots of each cultivar were fertilized three times per week with 250 mt of nutrient solution containing additional Ca (10 mM) and NO3 (25 mM) and watered well. Beginning 21 days after planting (DAP) and every three weeks thereafter up to 84 days, the second leaf from the growing axis (main stem) was detached to determine CO2 effect on leaf area, specific leaf area (SLA) and dry weight. Plants were harvested 97 DAP, at which time total leaf area, leaf number, plant and root weights and pod production data were taken. Numbers of pods per plant, pod fresh and dry weights, fibrous root and plant dry weights were higher for all cultivars grown at 700 mu mol mol(-1) than at ambient CO2. Also, leaf area for all cultivars was larger with CO2 enrichment than at ambient. SLA tended to decline with time regardless of CO2 treatment. Percentage of total sound mature kernels (%TSMK) was similar for both treatments. Plants grown at 700 mu mol mol(-1) CO2 had slightly more immature pods and seeds at final harvest. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 Tuskegee Univ, George Washington Carver Agr Expt Stn, NASA, Ctr CELSS, Tuskegee, AL 36088 USA. RP Mortley, DG (reprint author), Tuskegee Univ, George Washington Carver Agr Expt Stn, NASA, Ctr CELSS, Tuskegee, AL 36088 USA. FU CSAP SAMHSA HHS [ALX-SP-1] NR 3 TC 3 Z9 5 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1905 EP 1908 DI 10.1016/S0273-1177(97)00859-4 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900016 PM 11542568 ER PT S AU Stutte, GW Wheeler, RM AF Stutte, GW Wheeler, RM BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Accumulation and effect of volatile organic compounds in closed life support systems SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID EMISSIONS AB Bioregenerative life support systems (BLSS) being considered for long duration space missions will operate with limited resupply and utilize biological systems to revitalize the atmosphere, purify water, and produce food. The presence of man-made materials, plant and microbial communities, and human activities will result in the production of volatile organic compounds (VOCs). A database of VOC production from potential BLSS crops is being developed by the Breadboard Project at Kennedy Space Center. Most research to date has focused on the development of air revitalization systems that minimize the concentration of atmospheric contaminants in a closed environment. Similar approaches are being pursued in the design of atmospheric revitalization systems in bioregenerative life support systems. In a BLSS one must consider the effect of VOC concentration on the performance of plants being used for water and atmospheric purification processes. In addition to phytotoxic responses, the impact of removing biogenic compounds from the atmosphere on BLSS function needs to be assessed. This paper provides a synopsis of criteria for setting exposure limits, gives an overview of existing information, and discusses production of biogenic compounds from plants grown in the Biomass Production Chamber at Kennedy Space Center. Published by Elsevier Science Ltd on behalf of COSPAR. C1 Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. NASA, Biomed Operat & Res Off, Kennedy Space Ctr, FL 32899 USA. RP Stutte, GW (reprint author), Dynamac Corp, Mail Code DYN-3, Kennedy Space Ctr, FL 32899 USA. NR 31 TC 15 Z9 16 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES-SERIES PY 1997 VL 20 IS 10 BP 1913 EP 1922 DI 10.1016/S0273-1177(97)00625-X PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900017 PM 11542569 ER PT S AU Greene, C Bubenheim, DL Wignarajah, K AF Greene, C Bubenheim, DL Wignarajah, K BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Significance of rhizosphere microorganisms in reclaiming water in a CELSS SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID INDUSTRIAL WASTE-WATER; MEMBRANE BIOREACTOR; MINERALIZATION; BIODEGRADATION; SURFACTANTS; BIOMASS AB Plant-microbe interactions, such as those of the rhizosphere, may be ideally suited for recycling water in a Controlled Ecological Life Support System (CELSS). The primary contaminant of waste hygiene water will be surfactants or soaps. We identified changes in the microbial ecology in the rhizosphere of hydroponically grown lettuce during exposure to surfactant. Six week old lettuce plants were transferred into a chamber with a recirculating hydroponic system. Microbial density and population composition were determined for the nutrient solution prior to introduction of plants and then again with plants prior to surfactant addition. The surfactant Igepon was added to the recirculating nutrient solution to a final concentration of 1.0 g L-1. Bacteria density and species diversity of the solution were monitored over a 72-h period following introduction of Igepon. Nine distinct bacterial types were identified in the rhisosphere; three species accounted for 87% of the normal rhizosphere population. Microbial cell number increased in the presence of Igepon, however species diversity declined. At the point when Igepon was degraded from solution, diversity was reduced to only two species. Igepon was found to be degraded directly by only one species found in the rhizosphere. Since surfactants are degraded from the waste hygiene water within 24 h, the potential for using rhizosphere bacteria as a waste processor in a CELSS is promising. Published by Elsevier Science Ltd on behalf of COSPAR. C1 Lockheed Martin Engn & Sci Corp, Ames Res Ctr, Space Technol Div, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. RP Greene, C (reprint author), Lockheed Martin Engn & Sci Corp, Ames Res Ctr, Space Technol Div, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. NR 23 TC 1 Z9 1 U1 0 U2 6 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1949 EP 1958 DI 10.1016/S0273-1177(97)00860-0 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900023 PM 11542575 ER PT S AU Wheeler, RM Mackowiak, CL Stutte, GW Yorio, NC Berry, WL AF Wheeler, RM Mackowiak, CL Stutte, GW Yorio, NC Berry, WL BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Effect of elevated carbon dioxide on nutritional quality of tomato SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res ID CO2 AB Tomato (Lycopersicon esculentum Mill.) cvs. Red Robin (RR) and Reimann Philipp (RP) were grown hydroponically for 105 d with a 12 h photoperiod, 26 degrees C /22 degrees C thermoperiod, and 500 mu mol.m(-2).s(-1) PPF at either 400, 1200, 5000, or 10,000 mu mol.mol(-1) (0.04, 0.12, 0.50, 1.00 kPa) CO2. Harvested fruits were analyzed for proximate composition, total dietary fiber, nitrate, and elemental composition. No trends were apparent with regard to CO2 effects on proximate composition, with fruit from all treatments and both cultivars averaging 18.9% protein, 3.6% fat, 10.2% ash, and 67.2% carbohydrate. In comparison, average values for field-grown fruit are 16.6% protein, 3.8% fat, 8.1% ash, and 71.5% carbohydrate (Duke and Atchely, 1986). Total dietary fiber was highest at 10,000 mu mol.mol(-1) (28.4% and 22.6% for RR and RP) and lowest at 1000 mu mol.mol(-1) (18.2% and 15.9% for RR and RP), but showed no overall trend in response to CO2. Nitrate values ranged from 0.19% to 0.35% and showed no trend with regard to CO2. K, Mg, and P concentrations showed no trend in response to CO2 but Ca levels increased from 198 and 956 ppm in RR and RP at 400 mu mol.mol(-1), to 2537 and 2825 ppm at 10,000 mu mol.mol(-1). This increase in Ca caused an increase in fruit Ca/P ratios from 0.07 and 0.37 for RR and RP at 400 mu mol.mol(-1). to 0.99 and 1.23 for RR and RP at 10,000 mu mol.mol(-1), suggesting that more dietary Ca should be available from high CO2-grown fruit. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Biomed Off, Kennedy Space Ctr, FL 32899 USA. Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. RP Wheeler, RM (reprint author), NASA, Biomed Off, Mail Code 11-G, Kennedy Space Ctr, FL 32899 USA. NR 15 TC 7 Z9 8 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 1975 EP 1978 DI 10.1016/S0273-1177(97)00263-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900026 PM 11542578 ER PT S AU Bubenheim, DL Wignarajah, K AF Bubenheim, DL Wignarajah, K BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Recycling of inorganic nutrients for hydroponic crop production following incineration of inedible biomass SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB The goal of resource recovery in a regenerative life support system is maintenance of product quality to insure support of reliable and predictable levels of life support function performance by the crop plant component, Further, these systems must be maintained over extended periods of time, requiring maintenance of nutrient solutions to avoid toxicity and deficiencies, The focus of this study was to determine the suitability of the ash product following incineration of inedible biomass as a source of inorganic nutrients for hydroponic crop production, Inedible wheat biomass was incinerated and ash quality characterized, The incinerator ash was dissolved in adequate nitric acid to establish a consistent nitrogen concentration is all nutrient solution treatments, Four experimental nutrient treatments were included: control, ash only, ash supplemented to match the control treatment, and ash only quality formulated with reagent grade chemicals, When nutrient solutions were formulated using only ash following incineration of inedible biomass, a balance in solution is established representing elemental retention following incineration and nutrient proportions present in the original biomass, The resulting solution is not identical to the control, This imbalance resulted in a suppression of crop growth. When the ash is supplemented with reagent grade chemicals to establish the same balance as in the control growth is identical to the control, The ash appears to carry no phytotoxic materials. Growth in solution formulated with reagent grade chemicals but matching the quality of the ash only treatment resulted in similar growth to that of the ash only treatment, The ash product resulting from incineration of inedible biomass appears to be a suitable form for recycle of inorganic nutrients to crop production, Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Ames Res Ctr, Div Space Sci,Lockheed Martin Engn & Sci Corp, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. RP Bubenheim, DL (reprint author), NASA, Ames Res Ctr, Div Space Sci,Lockheed Martin Engn & Sci Corp, Regenerat Life Support Branch, Moffett Field, CA 94035 USA. NR 10 TC 5 Z9 5 U1 0 U2 5 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 2029 EP 2035 DI 10.1016/S0273-1177(97)00937-X PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900033 PM 11542586 ER PT S AU Bubenheim, DL Lewis, C AF Bubenheim, DL Lewis, C BE Wheeler, RM Garland, JL Tibbitts, TW Nielsen, SS Michell, CA TI Application of NASA's advanced life support technologies in polar regions SO LIFE SCIENCES: LIFE SUPPORT SYSTEMS STUDIES-I SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F4.6, F4.8, F4.2 and F4.9 Symposia of COSPAR Scientific Commission F on Life Sciences - Life Support System Studies-I, at the 31st COSPAR Scientific Assembly CY JUL 14-SEP 21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res AB NASA's advanced life support technologies are being combined with Arctic science and engineering knowledge in the Advanced Life Systems for Extreme Environments (ALSEE) project. This project addresses-treatment and reduction of waste, purification and recycling of water, and production of food in remote communities of Alaska. The project focus is a major issue in the state of Alaska and other areas of the Circumpolar North; the health and welfare of people, their lives and the subsistence lifestyle in remote communities, care for the environment, and economic opportunity through technology transfer. The challenge is to implement the technologies in a manner compatible with the social and economic structures of native communities, the state, and the commercial sector. NASA gods are technology selection, system design and methods development of regenerative life support systems for planetary and Lunar bases and other space exploration missions. The ALSEE project will provide similar advanced technologies to address the multiple problems facing the remote communities of Alaska and provide an extreme environment testbed for future space applications. These technologies have never been assembled for this purpose. They offer an integrated approach to solving pressing problems in remote communities. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Alaska, Dept Nat Resources, Ctr Appl Res, Fairbanks, AK 99701 USA. Univ Alaska, Dept Nat Resources, Agr & Forestry Expt Stn, Fairbanks, AK 99701 USA. RP Bubenheim, DL (reprint author), NASA, Ames Res Ctr, Mail Stop 239-15, Moffett Field, CA 94035 USA. NR 18 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043307-3 J9 ADV SPACE RES PY 1997 VL 20 IS 10 BP 2037 EP 2044 DI 10.1016/S0273-1177(97)00938-1 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK42A UT WOS:000072090900034 PM 11542587 ER PT B AU Meyer, WV Cannell, DS Smart, AE Taylor, TW Tin, P AF Meyer, WV Cannell, DS Smart, AE Taylor, TW Tin, P BE Pike, ER Abbiss, JB TI Suppression of multiple scattering using a single beam cross-correlation method SO LIGHT SCATTERING AND PHOTON CORRELATION SPECTROSCOPY SE NATO ADVANCED SCIENCE INSTITUTE SERIES, SUB-SERIES 3, HIGH TECHNOLOGY LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Light Scattering and Photon Correlation Spectroscopy CY AUG 26-30, 1996 CL KRAKOW, POLAND SP NATO, Sci Affairs Div, USN, Off Naval Res, European Off AB We present a simple, single beam, laser light scattering technique which discriminates against multiple scattering in turbid media using cross-correlation of the scattered intensity at slightly different spatial positions. Experimental results obtained at a scattering angle of 90 degrees for colloidal suspensions of various concentrations show that the technique yields information on particle diameter, even for samples which rue visually opaque. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Meyer, WV (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, MS 105-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4736-6 J9 NATO ASI 3 HIGH TECH PY 1997 VL 40 BP 39 EP 50 PG 12 WC Physics, Multidisciplinary; Spectroscopy SC Physics; Spectroscopy GA BK15E UT WOS:000071347400004 ER PT J AU Thompson, JB SchultzeLam, S Beveridge, TJ DesMarais, DJ AF Thompson, JB SchultzeLam, S Beveridge, TJ DesMarais, DJ TI Whiting events: Biogenic origin due to the photosynthetic activity of cyanobacterial picoplankton SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID CALCIUM-CARBONATE PRECIPITATION; WATER LAKE; NEW-YORK; MARINE; FRACTIONATION; MICROSCOPY; CHEMISTRY; SEDIMENTS; C-13; CO2 AB An annual whiting event occurs each year in late May to early June in Fayetteville Green Lake, New York. The initiation of this event correlates with exponential growth of the Synechococcus population within the lake. Synechococcus is the dominant (by similar to 4 orders of magnitude) autotrophic organism owing to the oligotrophic condition of the lake. The delta(13)C values of the dissolved inorganic C range seasonally from -9.5 parts per thousand in winter to -6.2 parts per thousand in summer due to photosynthetic activity. Calcite precipitates principally in the microenvironment surrounding Synechococcus because of a photosynthetically driven alkalization process and the availability of the cells as nucleation sites. This calcite has a heavier delta(13)C value (>4 parts per thousand) than does the dissolved inorganic C of the lake water owing to the cells preferential uptake of C-12. A conceptual model suggests that photosynthetic activity and cell surface chemistry, together with the substantial surface area that arises from the great abundance of micron-sized cells, allow Synechococcus to dominate the annual whiting events in Fayetteville Green Lake. C1 UNIV GUELPH,COLL BIOL SCI,DEPT MICROBIOL,GUELPH,ON N1G 2W1,CANADA. AMES RES CTR,MOFFETT FIELD,CA 94035. RP Thompson, JB (reprint author), ECKERD COLL,DEPT MARINE SCI,4200 54TH AVE S,ST PETERSBURG,FL 33711, USA. NR 40 TC 156 Z9 163 U1 2 U2 41 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD JAN PY 1997 VL 42 IS 1 BP 133 EP 141 PG 9 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XK601 UT WOS:A1997XK60100013 PM 11541205 ER PT B AU Gunapala, SD Bandara, SV Liu, JK Hong, W Sundaram, M Maker, PD Muller, RE Shott, CA Carralejo, R AF Gunapala, SD Bandara, SV Liu, JK Hong, W Sundaram, M Maker, PD Muller, RE Shott, CA Carralejo, R BE Li, SS Liu, HC Tidrow, MZ TI Fabrication and characterization of 640 x 486 GaAs based quantum well infrared photodetector (QWIP) snap-shot camera SO LONG WAVELENGTH INFRARED DETECTORS AND ARRAYS: PHYSICS AND APPLICATIONS V SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 5th International Symposium on Long Wavelength Infrared Detectors and Arrays - Physics and Applications at the Joint International Meeting of the ECS/ISE CY AUG 31-SEP 05, 1997 CL PARIS, FRANCE SP Phillips Lab, Air Force Wright Lab, Jet Propulsion Lab DE intersubband transitions; infrared (IR); long-wavelength Infrared (LWIR); gallium arsenide (GaAs); quantum well infrared photodetector (QWIP); focal plane arrays; noise equivalent temperature difference (NE Delta T); infrared imaging cameras AB A 9 mu m cutoff 640x486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE Delta T) of 36 mK has been achieved. In this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NE Delta T, uniformity, and operability. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-186-2 J9 ELEC SOC S PY 1997 VL 33 BP 14 EP 21 PG 8 WC Electrochemistry; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Electrochemistry; Engineering; Optics; Physics GA BK68U UT WOS:000073091700002 ER PT B AU Bandara, S Gunapala, S Liu, J Hong, W Park, J AF Bandara, S Gunapala, S Liu, J Hong, W Park, J BE Li, SS Liu, HC Tidrow, MZ TI Optical coupling mechanisms in quantum well infrared photodetectors SO LONG WAVELENGTH INFRARED DETECTORS AND ARRAYS: PHYSICS AND APPLICATIONS V SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 5th International Symposium on Long Wavelength Infrared Detectors and Arrays - Physics and Applications at the Joint International Meeting of the ECS/ISE CY AUG 31-SEP 05, 1997 CL PARIS, FRANCE SP Phillips Lab, Air Force Wright Lab, Jet Propulsion Lab AB Alternate light coupling system, such as gratings are required because Quantum Well Infrared Photodetectors do not respond to normal incident light due to the quantum mechanical selection rules associated with intersubband transitions. The resolution of the photolithography and accuracy of the etching become key issues in producing smaller grating feature sizes especially in shorter wavelengths. A factor of three enhancement due to 2D periodic grating fabricated on QWIP structure was observed. Variation of the enhancement factor with grove depth and feature size of the grating can be theoretically explained. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Bandara, S (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-186-2 J9 ELEC SOC S PY 1997 VL 33 BP 191 EP 198 PG 8 WC Electrochemistry; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Electrochemistry; Engineering; Optics; Physics GA BK68U UT WOS:000073091700018 ER PT B AU de Koter, A AF de Koter, A BE Nota, A Lamers, HJG TI Is the maximum phase of LBVs caused by increased mass loss? SO LUMINOUS BLUE VARIABLES : MASSIVE STARS IN TRANSITION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Luminous Blue Variables - Massive Stars in Transition CY OCT 06-12, 1996 CL KONA, HI SP Astron Soc Pacific AB We review the concept of 'pseudo' photospheres and show - using a heuristic model - that mass loss changes can not explain the observed stellar radius changes in LBV stars during typical variations. We also discuss the reverse problem, namely the Likely effect of a change in radius on the stellar mass loss. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP de Koter, A (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-40-6 J9 ASTR SOC P PY 1997 VL 120 BP 66 EP 70 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80A UT WOS:000073440700012 ER PT B AU Corcoran, MF Swank, JH Petre, R Drake, S Ishibashi, K AF Corcoran, MF Swank, JH Petre, R Drake, S Ishibashi, K BE Nota, A Lamers, HJG TI X-ray emission and variability of eta Car SO LUMINOUS BLUE VARIABLES : MASSIVE STARS IN TRANSITION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Luminous Blue Variables - Massive Stars in Transition CY OCT 06-12, 1996 CL KONA, HI SP Astron Soc Pacific AB We review the characteristics of the X-ray emission from the peculiar massive star eta Car, using archival data as well as recent observations. We examine the evidence for variations in the X-ray flux from the star, and explore relations between changes in the X-ray emission and variability at other energies. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-40-6 J9 ASTR SOC P PY 1997 VL 120 BP 267 EP 271 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80A UT WOS:000073440700059 ER PT B AU Lyster, PM Larson, JW Guo, J Sawyer, W da Silva, A Stajner, I Ding, CHQ Ferraro, R AF Lyster, PM Larson, JW Guo, J Sawyer, W da Silva, A Stajner, I Ding, CHQ Ferraro, R BE Hoffmann, GR Kreitz, N TI Progress in the parallel implementation of the physical-space statistical analysis system (PSAS) SO MAKING ITS MARK LA English DT Proceedings Paper CT 7th ECMWF Workshop on the Use of Parallel Processors in Meteorology CY NOV 02-06, 1996 CL READING, ENGLAND SP European Ctr Medium Range Weather Forecasts AB The Physical-space Statistical Analysis System (PSAS) comprises the core analysis scheme for the Goddard Earth Observing System (GEOS) atmospheric data assimilation system. The Data assimilation Office (DAO) of the National Aeronautics and Space Administration (NASA) developed both GEOS and PSAS, and are currently in the process of constructing a parallel implementation of GEOS. Here we discuss progress in the parallel implementation of PSAS, as well as issues related to the parallelization of an enhanced PSAS capable of direct assimilation of non-state variables (e.g., radiances). C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Lanham, MD 20706 USA. RP Lyster, PM (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Lanham, MD 20706 USA. RI da Silva, Arlindo/D-6301-2012 OI da Silva, Arlindo/0000-0002-3381-4030 NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3350-7 PY 1997 BP 382 EP 393 PG 2 WC Computer Science, Interdisciplinary Applications; Meteorology & Atmospheric Sciences SC Computer Science; Meteorology & Atmospheric Sciences GA BM17V UT WOS:000077914900031 ER PT J AU Ryer, CH Olla, BL AF Ryer, CH Olla, BL TI Altered search speed and growth: social versus independent foraging in two pelagic juvenile fishes SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE bioenergetics; foraging strategy; growth; milkshake effect; shoaling; swimming speed ID THERAGRA-CHALCOGRAMMA; ANOPLOPOMA-FIMBRIA; WALLEYE POLLOCK; BEHAVIOR; METABOLISM; BIOENERGETICS; SABLEFISH; EVOLUTION; ECOLOGY; PREY AB Prior studies have demonstrated that juvenile walleye pollock Theragra chalcogramma forage socially in schools for spatially and temporally clumped food, but forage more independently for spatially and temporally dispersed food. One advantage of social foraging is that fish in schools may be able to locate more food clumps than fish foraging individually. However, data also indicate that walleye pollock swim faster when foraging socially. We conducted laboratory experiments to evaluate the effect of food distribution upon the energetic foraging costs incurred by juvenile walleye pollock and sablefish Anaplopoma fimbria. We predicted that when given identical rations, fish receiving clumped food would swim faster, expending more energy, and therefore grow more slowly than fish receiving dispersed food. After 2 wk under these 2 foraging regimes, juvenile walleye pollock receiving clumped food swam 50 % faster, but experienced 19 % lower growth, than walleye pollock receiving dispersed food. Sablefish demonstrated only a weak swim speed response, with no difference in growth between food distributions. Our results demonstrate that although social foraging may increase encounter rates with food, in some species there may also be an energetic cost for this behavior, which will have an influence upon energetic efficiency, potentially affecting growth and survival. RP Ryer, CH (reprint author), OREGON STATE UNIV, HATFIELD MARINE SCI CTR, NATL MARINE FISHERIES SERV, ALASKA FISHERIES SCI CTR, NEWPORT, OR 97365 USA. NR 51 TC 15 Z9 15 U1 2 U2 3 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 1997 VL 153 BP 273 EP 281 DI 10.3354/meps153273 PG 9 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA XR974 UT WOS:A1997XR97400025 ER PT J AU Minello, TJ Webb, JW AF Minello, TJ Webb, JW TI Use of natural and created Spartina alterniflora salt marshes by fishery species and other aquatic fauna in Galveston Bay, Texas, USA SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE salt marsh; habitat value; habitat creation; restoration; nekton; fishery species ID FUNDULUS-HETEROCLITUS; PENAEUS-AZTECUS; BROWN SHRIMP; TIDAL MARSH; NEKTON USE; DECAPOD CRUSTACEANS; PALAEMONETES-PUGIO; NATANT MACROFAUNA; ORGANIC-CARBON; SOUTH-CAROLINA AB We compared densities of nekton and infauna among 5 natural and 10 created (3 to 15 yr in age) salt marshes in the Galveston Bay system of Texas to test whether these marshes were functionally equivalent. Decapod crustaceans dominated the nekton on the marsh surface during both the spring and the fall. Densities of daggerblade grass shrimp Palaemonetes pugio, the most abundant decapod, were not significantly different among marshes, but the size of these shrimp in created marshes was significantly smaller than in natural marshes. Densities of the marsh grass shrimp Palaemonetes vulgaris and of 3 commercially-important crustaceans (white shrimp Penaeus setiferus, brown shrimp Penaeus aztecus, and blue crab Callinectes sapidus) were significantly lower in created marshes than in natural marshes. Gulf menhaden Brevoortia patronus were the most abundant fish collected, mainly on nonvegetated bottom adjacent to marsh habitats. Fish densities within vegetation (predominantly gobies and pinfish Lagodon rhomboides) were significantly lower in created marshes than in natural marshes. Natural and created marshes, however, did not differ in species richness of nekton. Sediment macro-organic matter and density and species richness of macroinfauna (mainly polychaete worms) were all significantly lower in created marshes than natural marshes. There was a positive relationship in created marshes between marsh age and sediment macro-organic matter, but marsh age was not related to nekton densities. Natural marshes were similar in having low elevations and flooding durations between 74 and 80% of the year; while created marshes were flooded from 43 to 91% of the time. In contrast to marsh age, tidal flooding was often related to nekton densities in marsh habitats. We conclude that marsh elevation and tidal flooding are key characteristics affecting use by nekton and should be considered in marsh construction projects. C1 TEXAS A&M UNIV, DEPT MARINE BIOL, GALVESTON, TX 77553 USA. RP Minello, TJ (reprint author), NATL MARINE FISHERIES SERV, SE FISHERIES SCI CTR, GALVESTON LAB, 4700 AVE U, GALVESTON, TX 77551 USA. NR 64 TC 97 Z9 99 U1 1 U2 32 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PY 1997 VL 151 IS 1-3 BP 165 EP 179 DI 10.3354/meps151165 PG 15 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA XE687 UT WOS:A1997XE68700017 ER PT J AU OSullivan, S Mullin, KD AF OSullivan, S Mullin, KD TI Killer whales (Orcinus orca) in the northern Gulf of Mexico SO MARINE MAMMAL SCIENCE LA English DT Article C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,PASCAGOULA,MS 39568. NR 29 TC 5 Z9 8 U1 0 U2 3 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JAN PY 1997 VL 13 IS 1 BP 141 EP 147 DI 10.1111/j.1748-7692.1997.tb00618.x PG 7 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA WF733 UT WOS:A1997WF73300009 ER PT B AU Crenshaw, DM AF Crenshaw, DM BE Arav, N Shlosman, I Weymann, RJ TI Intrinsic UV absorption in Seyfert galaxies SO MASS EJECTION FROM ACTIVE GALACTIC NUCLEI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Mass Ejection from Active Galactic Nuclei CY FEB 19-21, 1997 CL CARNEGIE OBSERV, PASADENA, CA SP NASA HO CARNEGIE OBSERV AB HST spectra show that intrinsic UV absorption lines occur in at least half of the Seyfert 1 galaxies observed. In every case thus far, at least a portion of the broad emission-line region is occulted, and in several cases, the covering factor in the line-of-sight is known to be close to one. Thus the global covering factor is probably greater than or equal to 0.5, which is higher than that estimated for the classic broad and narrow emission-line regions, but similar to that determined for the X-ray "warm absorber". In a small sample observed by I-IST and ASCA, all of the Seyfert galaxies with a warm absorber also show intrinsic UV absorption, although in some cases the UV lines come primarily from regions characterized by lower ionization parameters. Simultaneous UV and X-ray monitoring will help to determine the nature of the absorption components. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crenshaw, DM (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-48-1 J9 ASTR SOC P PY 1997 VL 128 BP 121 EP 125 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80H UT WOS:000073445300019 ER PT B AU Mushotzky, RF AF Mushotzky, RF BE Arav, N Shlosman, I Weymann, RJ TI The X-ray view of AGNs - an overview SO MASS EJECTION FROM ACTIVE GALACTIC NUCLEI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Mass Ejection from Active Galactic Nuclei CY FEB 19-21, 1997 CL CARNEGIE OBSERV, PASADENA, CA SP NASA HO CARNEGIE OBSERV AB Recent ASCA and ROSAT X-ray observations of active galaxies have revealed a host of new data on the fundamental properties of active galaxies. Amongst these are the discovery and characterization of absorption by ionized gas in Seyfert 1 galaxies (the "warm absorber"), the discovery and parameterization of broad Fe K lines which originate in the central 100 Schwarzschild radii, a substantial modification in the form of the ionization continuum from previous models and the absence of Xray emission from broad absorption line quasars. We briefly summarize the present observational situation and indicate where this field might progress in the next few years with the enhanced capabilities of AXAF, XMM and Astro-E. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mushotzky, RF (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-48-1 J9 ASTR SOC P PY 1997 VL 128 BP 141 EP 154 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80H UT WOS:000073445300022 ER PT J AU Britton, DL AF Britton, DL TI The lightweight nickel fiber electrode for nickel-based battery systems SO MATERIALS AND MANUFACTURING PROCESSES LA English DT Article AB Development of a high specific energy battery is one of the objectives of the lightweight nickel-hydrogen (Ni-H-2) program at the NASA Lewis Research center. The approach has been to improve the nickel electrode by continuing combined in house and contract efforts to develop a more efficient and lighter weight electrode for the nickel-hydrogen cell. Small fiber diameter nickel plaques are used as conductive supports for the nickel hydrogen active material. These plaques have an advantage of increased surface area available for the deposition of active material. Initial tests include activation and capacity measurements at different discharge rates followed by life cycling. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 6 TC 0 Z9 0 U1 0 U2 1 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 SN 1042-6914 J9 MATER MANUF PROCESS JI Mater. Manuf. Process. PY 1997 VL 12 IS 3 BP 429 EP 436 DI 10.1080/10426919708935156 PG 8 WC Engineering, Manufacturing; Materials Science, Multidisciplinary SC Engineering; Materials Science GA XE980 UT WOS:A1997XE98000005 ER PT S AU Ehrlich, JE Wu, XL Lee, IYS Heikal, AA Hu, ZY Rockel, H Marder, SR Perry, JW AF Ehrlich, JE Wu, XL Lee, IYS Heikal, AA Hu, ZY Rockel, H Marder, SR Perry, JW BE Sutherland, R Pachter, R Hood, P Hagan, D Lewis, K Perry, J TI Two-photon absorbing organic chromophores for optical limiting SO MATERIALS FOR OPTICAL LIMITING II SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials for Optical Limiting II, at 1997 MRS Spring Meeting CY MAR 31-APR 02, 1997 CL SAN FRANCISCO, CA SP Mat Res Soc, USAF, Wright Lab, Def Res Agcy, UK, Sci Applicat Int Corp AB Strong optical limiting and large two-photon absorptivities are reported for a class of bis-donor diphenylpolyene derivatives with varying polyene bridge lengths. These molecules exhibit strong optical limiting using nanosecond pulses over a broad spectral range. Bis(diphenylamino)stilbene exhibits a 90 nm red shift of its optical limiting band, and only a minimal shift of about 13 nm of its lowest one-photon electronic absorption band relative to bis(di-n-butylamino)stilbene. This suggests a potential for broadband optical limiting with high transparency using mixtures of such compounds. Pulse width dependent nonlinear transmission measurements suggest that two-photon pumped excited-state absorption contributes significantly to the limiting of nanosecond pulses. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ehrlich, JE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 0 TC 23 Z9 24 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-383-5 J9 MATER RES SOC SYMP P PY 1997 VL 479 BP 9 EP 15 PG 7 WC Materials Science, Multidisciplinary; Optics SC Materials Science; Optics GA BK27B UT WOS:000071653700002 ER PT S AU Ounaies, Z Young, JA Simpson, JO Farmer, BL AF Ounaies, Z Young, JA Simpson, JO Farmer, BL BE George, EP Gotthardt, R Otsuka, K TrolierMcKinstry, S WunFogle, M TI Dielectric properties of piezoelectric polyimides SO MATERIALS FOR SMART SYSTEMS II SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials for Smart Systems II, at the 1996 MRS Fall Meeting CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc, USA Res Off, Furukawa Elect Co Ltd, Oak Ridge Natl Lab, PIOLAX Inc AB Molecular modeling and dielectric measurements are being used to identify mechanisms governing piezoelectric behavior in polyimides such as dipole orientation during poling, as well as degree of piezoelectricity achievable. Molecular modeling on polyimides containing pendant, polar nitrile (CN) groups has been completed to determine their remanent polarization. Experimental investigation of their dielectric properties evaluated as a function of temperature and frequency has substantiated numerical predictions. With this information in hand, we are then able to suggest changes in the molecular structures, which will then improve upon the piezoelectric response. RP Ounaies, Z (reprint author), NASA,LANGLEY RES CTR,NATL RES COUNCIL,HAMPTON,VA 23681, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-363-0 J9 MATER RES SOC SYMP P PY 1997 VL 459 BP 53 EP 58 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Materials Science, Composites SC Materials Science GA BH71E UT WOS:A1997BH71E00007 ER PT S AU Simpson, J Ounaies, Z Fay, C AF Simpson, J Ounaies, Z Fay, C BE George, EP Gotthardt, R Otsuka, K TrolierMcKinstry, S WunFogle, M TI Polarization and piezoelectric properties of a nitrile substituted polyimide SO MATERIALS FOR SMART SYSTEMS II SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials for Smart Systems II, at the 1996 MRS Fall Meeting CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc, USA Res Off, Furukawa Elect Co Ltd, Oak Ridge Natl Lab, PIOLAX Inc AB This research focuses on the synthesis and characterization of a piezoelectric (beta-CN)-APB/ODPA polyimide. The remanent polarization and piezoelectric d(31) and g(33) coefficients are reported to assess the effect of synthesis variations. Each of the materials exhibits a level of piezoelectricity which increases with temperature. The remanent polarization is retained at temperatures close to the glass transition temperature of the polyimide. RP Simpson, J (reprint author), NASA,LANGLEY RES CTR,COMPOSITES & POLYMERS BRANCH,HAMPTON,VA 23681, USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-363-0 J9 MATER RES SOC SYMP P PY 1997 VL 459 BP 59 EP 64 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Materials Science, Composites SC Materials Science GA BH71E UT WOS:A1997BH71E00008 ER PT S AU Jordan, TL Ounaies, Z Turner, TL AF Jordan, TL Ounaies, Z Turner, TL BE George, EP Gotthardt, R Otsuka, K TrolierMcKinstry, S WunFogle, M TI Complex piezoelectric coefficients of PZT ceramics: Method for direct measurement of d(33) SO MATERIALS FOR SMART SYSTEMS II SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials for Smart Systems II, at the 1996 MRS Fall Meeting CY DEC 02-05, 1996 CL BOSTON, MA SP Mat Res Soc, USA Res Off, Furukawa Elect Co Ltd, Oak Ridge Natl Lab, PIOLAX Inc AB A seer-optic device is used to determine the magnitude and phase of the strain in the poling direction of lead zirconate titanate (PZT) ceramic wafers. This information yields the real and imaginary components of the piezoelectric strain coefficient d(33). The measurement hardware and software are described and results from the measurements of d(33) for PZT 4 and 5 H wafers are presented. This method has the advantages of being direct, inexpensive and relatively simple to use. Verification of the results is provided through the use of the resonance method. RP Jordan, TL (reprint author), NASA,LANGLEY RES CTR,DATA SYST & INSTRUMENT SUPPORT BRANCH,HAMPTON,VA 23681, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-363-0 J9 MATER RES SOC SYMP P PY 1997 VL 459 BP 231 EP 236 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Materials Science, Composites SC Materials Science GA BH71E UT WOS:A1997BH71E00032 ER PT S AU Rutledge, SK Banks, BA AF Rutledge, SK Banks, BA BE Vandiver, PB Druzik, JR Merkel, JF Stewart, J TI Atomic oxygen treatment technique for removal of smoke damage from paintings SO MATERIALS ISSUES IN ART AND ARCHAEOLOGY V SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Materials Issues in Art and Archaeology V CY DEC 03-05, 1996 CL BOSTON, MA SP Mat Res Soc AB Soot deposits that can accumulate on surfaces of a painting during a fire can be difficult to clean from some types of paintings without damaging the underlying paint layers. A non-contact technique has been developed which can remove the soot by allowing a gas containing atomic oxygen to now over the surface and chemically react with the soot to form carbon monoxide and carbon dioxide. The reaction is limited to the surface, so the underlying paint is not touched. The process can be controlled so that the cleaning can be stopped once the paint surface is reached. This paper describes the smoke exposure and cleaning of untreated canvas, acrylic gesso, and sections of an oil painting using this technique. The samples were characterized by optical microscopy and reflectance spectroscopy. RP Rutledge, SK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 SN 0272-9172 BN 1-55899-366-5 J9 MATER RES SOC SYMP P PY 1997 VL 462 BP 369 EP 374 PG 6 WC Archaeology; Art; Materials Science, Multidisciplinary SC Archaeology; Art; Materials Science GA BJ83R UT WOS:A1997BJ83R00040 ER PT B AU Su, CH AF Su, CH BE Ramachandran, N TI Bulk growth of wide band gap II-VI compound semiconductors by physical vapor transport SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE physical vapor transport (PVT); II-VI compound semiconductors AB The mechanism of physical vapor transport of II-Tn semiconducting compounds was studied both theoretically, using a one-dimensional diffusion model, as well as experimentally. It was found that the vapor phase stoichiometry is critical in determining the vapor transport rate. The experimental heat treatment methods to control the vapor composition over the starting materials were investigated and the effectiveness of the heat treatments was confirmed by partial pressure measurements using an optical absorption technique. The effect of residual (foreign) gas on the transport rate was also studies theoretically by the diffusion model and confirmed experimentally by the measurements of total pressure and compositions of the residual gas. An in-situ dynamic technique for the transport rate measurements and a further extension of the technique that simultaneously measured the partial pressures and transport rates were performed and, for the first time, the experimentally determined mass fluxes were compared with those calculated, without any adjustable parameters, from the diffusion model. Using the information obtained from the experimental transport rate measurements as guideline high quality bulk crystal of wide band gap II-VT semiconductor were grown from the source materials which undergone the same heat treatment methods. The grown crystals were then extensively characterized with emphasis on the analysis of the crystalline structural defects. RP Su, CH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 0 TC 9 Z9 9 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 7 EP 21 DI 10.1117/12.277715 PG 15 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00002 ER PT B AU Palosz, W AF Palosz, W BE Ramachandran, N TI Inert gases in closed crystal growth systems SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE crystal growth; residual gas; diffusion of gases in silica AB The effect of desorption from, and diffusion through the wall on inert gas pressure in sealed fused silica ampoules was investigated. It is shown, that desorption from the surface and the bulk of silica may read to an accumulation of residual gas on the order of a few Torr or more upon annealing. A prior outgassing of the ampoules under vacuum at high temperature reduces the amount of gas released from the glass by al least one order of magnitude. Presence of oxide and other impurities in the source material was found to increase the residual gas pressure, affect its composition, and reduce:hz vapor transport rate in PVT systems. It is shown, that light gases(hydrogen, helium and neon) diffuse through silica wall and may change the pressure inside the sealed ampoule considerably even at moderate temperatures. RP Palosz, W (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES75,HUNTSVILLE,AL 35812, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 34 EP 43 DI 10.1117/12.277733 PG 10 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00004 ER PT B AU Palosz, W Lowry, S Krishnan, A AF Palosz, W Lowry, S Krishnan, A BE Ramachandran, N TI Modeling of thermal field in 'contactless' Physical Vapor Transport system SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Physical Vapor Transport; contactless growth; numerical modeling AB A numerical model of the thermal field in the furnace-ampoule system developed for the 'contactless' Physical Vapor Transport growth geometry is presented. The model is used to assess the effect of the system geometry and growth parameters on the conditions of 'contactless' growth of cadmium telluride crystals. RP Palosz, W (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES75,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 177 EP 183 DI 10.1117/12.277720 PG 7 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00019 ER PT B AU Duval, WMB Singh, NB Glicksman, ME AF Duval, WMB Singh, NB Glicksman, ME BE Ramachandran, N TI Damping of unsteady flows in the physical vapor transport process SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE crystals; microgravity; convection mercurous chloride; dynamical states; physical vapor transport AB The dynamics of the flow field during physical vapor transport of mercurous chloride is analyzed computationally for practical crystal growth conditions to distinguish between unsteady flow and thermal stress as the cause of crystal inhomogeneity. We analyze the flow field over the parametric range of 1.56x10(2) less than or equal to Ra less than or equal to 2.08x10(5), .011 less than or equal to Ar less than or equal to.112, and show that the effect of thermal stress as the cause of crystal inhomogeneity can bt: investigated by performing experiments with low aspect ratio enclosures for Ar<.028 and Ra<2.4x10(3) for which the flow becomes diffusive-advective. Dynamical characteristics of the flow field indicate a transition from chaotic flow Ra=2.08x10(5) to steady flow Ra<1.4x10(4) occurs through period doubling. A microgravity environment can be used effectively togrow high quality crystals, if thermal stresses are not the cause of crystal inhomogeneity, since unsteady flows are damped. regardless of the aspect ratio of the enclosure. RP Duval, WMB (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. OI Glicksman, Martin/0000-0002-2675-2759 NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 184 EP 194 DI 10.1117/12.277721 PG 11 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00020 ER PT B AU Mazuruk, K Ramachandran, N Su, CH AF Mazuruk, K Ramachandran, N Su, CH BE Ramachandran, N TI Modification of BCF theory due to step motion SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing AB Crystal growth kinetics from the vapor phase or from solution can be described by the diffusion of growth species to the echelon of equidistant steps present at vicinal surfaces. Diffusion takes place in a thin boundary layer adjacent to the interface. Present theories of this process neglect a convective transport mechanism in the boundary layer. In this work, we reexamine this zero-flow assumption. We consider the difference in the densities between the mother phase and the growing crystalline phase as the driving force for the flow. This force is localized at the step positions when only lateral growth of the steps is permitted. In such a case a highly nonuniform flow pattern is obtained. It consists of two vortices with the line between these vortices corresponding to a flow directed towards the step. This nonuniform part of the flow is found to extend into the mother phase up to an inter-step distance. This is the region where diffusion in the horizontal direction takes place. Consequently, the results suggest the importance of convective transport in the boundary layer. Finally, a constant horizontal few, far from the surface, is predicted. RP Mazuruk, K (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 195 EP 200 DI 10.1117/12.277722 PG 6 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00021 ER PT B AU Gillies, DC AF Gillies, DC BE Ramachandran, N TI NASA's microgravity materials science program SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE crystal growth; metals and alloys; glasses and ceramics; microgravity; non linear optics; polymers AB The Microgravity Research Division of NASA funds materials science research through biannual research programs known as NASA Research Announcements(NRA). Selection is via external peer review with proposals being categorized for ground based research or flight definition status. Topics of special interest to NASA are described in the NRAs and guidelines for successful proposals are outlined. The procedure for progressing from selection to a manifested flight experiment will involve further reviews of the science and also of the engineering needed to complete the experiment successfully. The topics of interest to NASA within the NRAs cover a comprehensive range of subjects, but with the common denominator that the proposed work must necessitate access to the microgravity environment for successful completion. Understanding of the fundamental nature of microstructure and its effects on properties is a major part of the program because it applies to almost all fields of materials science. Other important aspects of the program include non-linear optical materials, glasses and ceramics, metal and alloys and the need to develop materials science specifically to support NASA's Human Exploration and Development of Space (HEDS) enterprise. The transition to the International Space Station (ISS) represents the next stage oi the Materials Science program. RP Gillies, DC (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,MICROGRAV SCI & APPLICAT DIV,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 212 EP 217 DI 10.1117/12.277723 PG 6 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00023 ER PT B AU Hakimzadeh, R McPherson, KM Matisak, BP Wagar, WO AF Hakimzadeh, R McPherson, KM Matisak, BP Wagar, WO BE Ramachandran, N TI Effects of experiment location and orbiter attitude on the residual acceleration on-board STS-73 (USML-2) SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE quasi-steady; acceleration; OARE AB A knowledge of the quasi-steady acceleration environment on the NASA Space Shuttle Orbiter is of particular importance for materials processing experiments which are limited by slow diffusive processes. The quasi-steady (<1 HZ) acceleration environment on STS-73 (USML-2) was measured using the Orbital Acceleration Research Experiment (OARE) accelerometer. One of the facilities flown on USML-2 was the Crystal Growth Furnace (CGF), which was used by several Principal Investigators (PIs) to grow crystals. In this paper the OARE data mapped to the sample melt location within this furnace is presented. The ratio of the axial to radial components of the quasi-steady acceleration at the melt site is presented. Effects of Orbiter attitude on the acceleration data is discussed. RP Hakimzadeh, R (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 218 EP 229 DI 10.1117/12.277724 PG 12 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00024 ER PT B AU Bune, AV Gillies, DC Lehoczky, SL AF Bune, AV Gillies, DC Lehoczky, SL BE Ramachandran, N TI Numerical modeling of HgCdTe solidification: Effects of phase diagram, double-diffusion convection and microgravity level. SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE binary alloy; HgCdTe; bulk crystal growth; directional solidification; microgravity; numerical modelling; FIDAP AB A numerical model of HgCdTe solidification was implemented using finite the element code FIDAP. Model verification was done using both experimental data and numerical test problems. The model was used to evaluate possible effects of double-diffusion convection in molten material, and microgravity level on concentration distribution in the solidified HgCdTe. Particular attention was paid to incorporation of HgCdTe phase diagram. It was found, that below a critical microgravity amplitude, the maximum convective velocity in the melt appears virtually independent on the microgravity vector orientation. Good agreement between predicted interface shape and an interface obtained experimentally by quenching was achieved. The results of numerical modeling are presented in the form of video film. RP Bune, AV (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,NATL RES COUNCIL,ES 75,HUNTSVILLE,AL 35812, USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 241 EP 251 DI 10.1117/12.277727 PG 11 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00026 ER PT B AU Mazuruk, K Ramachandran, N Volz, MP Gillies, D AF Mazuruk, K Ramachandran, N Volz, MP Gillies, D BE Ramachandran, N TI Study of frequency effects of a rotating magnetic field on fluid flow in vertical cylinders SO MATERIALS RESEARCH IN LOW GRAVITY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on Materials Research in Low Gravity, at the SPIEs International Symposium on Optical Science, Engineering, and Instrumentation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing AB The body force generated by a rotating magnetic field applied to a cylindrical column of liquid metal of finite height is investigated theoretically Although an exact analytical formula has not been found, the proposed approach leads to a good approximate solution. It is demonstrated that the force field is significantly affected by the angular frequency of the rotating magnetic field, In the law-frequency limit, only the azimuthal component is present, while in the high frequency regime, a complex force field is induced which is composed of both azimuthal and meridional components. The resulting azimuthal now in the Stokesian regime has been numerically obtained and a counter-rotating profile has been demonstrated. The calculated results can be used to determine the fluid flow behavior during crystal growth in a weak rotating magnetic held. RP Mazuruk, K (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812, USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2545-1 J9 P SOC PHOTO-OPT INS PY 1997 VL 3123 BP 262 EP 271 DI 10.1117/12.277729 PG 10 WC Materials Science, Multidisciplinary; Remote Sensing; Optics SC Materials Science; Remote Sensing; Optics GA BJ22D UT WOS:A1997BJ22D00028 ER PT B AU Brennan, MC McGowan, AMR AF Brennan, MC McGowan, AMR BE Varadan, VV Chandra, J TI Piezoelectric power requirements for active vibration control SO MATHEMATICS AND CONTROL IN SMART STRUCTURES - SMART STRUCTURES AND MATERIALS 1997 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Mathematics and Control in Smart Structures - Smart Structures and Materials 1997 CY MAR 03-06, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Mech Engineers, USAF Wright Lab, Def Adv Res Projects Agcy, Amer Inst Chem Engineers, Amer Phys Soc, Div Mat Phys, Ceram Soc Japan, USA Res Lab, Intelligent Mat Forum, Japan DE piezoelectric; power; vibration; control; non-linear piezoelectric capacitance AB This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material nonlinearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined. RP Brennan, MC (reprint author), GEORGE WASHINGTON UNIV,JOINT INST ADVANCEMENT FLIGHT SCI,NASA,LANGLEY RES CTR,HAMPTON,VA, USA. NR 0 TC 18 Z9 18 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2452-8 J9 P SOC PHOTO-OPT INS PY 1997 VL 3039 BP 660 EP 669 DI 10.1117/12.276584 PG 10 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Mathematics, Applied; Optics SC Engineering; Materials Science; Mathematics; Optics GA BJ12X UT WOS:A1997BJ12X00060 ER PT J AU Bailey, DH Borwein, JM Crandall, RE AF Bailey, DH Borwein, JM Crandall, RE TI On the Khintchine constant SO MATHEMATICS OF COMPUTATION LA English DT Article DE Khintchine constant; continued fractions; geometric mean; harmonic mean; computational number theory; zeta functions; polylogarithms ID IRREGULAR PRIMES AB We present rapidly converging series for the Khintchine constant and for general ''Khintchine means'' of continued. fractions, We show that each of these constants can be cast in terms of an efficient free-parameter series, each series involving values of the Riemann zeta function, rationals, and logarithms of rationals. We provide an alternative, polylogarithm series for the Khintchine constant and indicate means to accelerate such series. We discuss properties of some explicit continued fractions, constructing specific fractions that have limiting geometric mean equal to the Khintchine constant. We report numerical evaluations of such special numbers and of various Khintchine means. In particular, we used an optimized series and a collection of fast algorithms to evaluate the Khintchine constant to more than 7000 decimal places. C1 SIMON FRASER UNIV, CTR EXPTL & CONSTRUCT MATH, BURNABY, BC B5A 1S6, CANADA. REED COLL, CTR ADV COMPUTAT, PORTLAND, OR 97202 USA. RP Bailey, DH (reprint author), NASA, AMES RES CTR, MAIL STOP T27A-1, MOFFETT FIELD, CA 94035 USA. RI Borwein, Jonathan/A-6082-2009; OI Borwein, Jonathan/0000-0002-1263-0646 NR 28 TC 15 Z9 16 U1 1 U2 1 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0025-5718 J9 MATH COMPUT JI Math. Comput. PD JAN PY 1997 VL 66 IS 217 BP 417 EP 431 DI 10.1090/S0025-5718-97-00800-4 PG 15 WC Mathematics, Applied SC Mathematics GA WE366 UT WOS:A1997WE36600026 ER PT S AU Ansari, RR Suh, KI Tumminia, SJ Russell, P Zigler, JS AF Ansari, RR Suh, KI Tumminia, SJ Russell, P Zigler, JS BE Altshuler, GB Birngruber, R DalFante, M Hibst, R Honigstmann, H Krasner, N Laffitte, F Katzir, A TI In-vivo "cataractograms" using a compact backscatter dynamic light scattering (DLS) probe SO MEDICAL APPLICATIONS OF LASERS IN DERMATOLOGY, OPHTHALMOLOGY, DENTISTRY, AND ENDOSCOPY, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Medical Applications of Lasers in Dermatology, Ophthalmology, Dentistry, and Endoscopy CY SEP 04-07, 1997 CL SAN REMO, ITALY SP Soc Italiana Laser Chirurg & Med, European Laser Assoc, Int Biomed Opt Soc, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev AB A compact fiber optic probe developed by Ansari et al.(1) for fluids experiments in the challenging conditions of a microgravity environment on-board a space shuttle orbiter has been applied to obtain "cataractograms" in transgenic mice to study early onset of cataractogenesis. Cataractograms are topographical contour maps of the lens which are obtained noninvasively by scanning the eye with the probe in three-dimensions (x, y, and z directions). This new method provides a visual means, in false color, for quantitative detection and monitoring of cataracts in the entire lens. The portion of lens mapped is only Limited by the degree of pupil dilation. The dilated pupil is about 1 mm for the transgenic mice system reported in this study. C1 NASA, Lewis Res Ctr, CWRU, Cleveland, OH 44135 USA. RP Ansari, RR (reprint author), NASA, Lewis Res Ctr, CWRU, MS 333-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 8 Z9 8 U1 2 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2624-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 3192 BP 202 EP 210 DI 10.1117/12.297843 PG 9 WC Dentistry, Oral Surgery & Medicine; Dermatology; Engineering, Biomedical; Gastroenterology & Hepatology; Ophthalmology; Optics SC Dentistry, Oral Surgery & Medicine; Dermatology; Engineering; Gastroenterology & Hepatology; Ophthalmology; Optics GA BK25Y UT WOS:000071632800029 ER PT S AU Tang, TK Gutierrez, RC Stell, CB Vorperian, V Arakaki, GA Rice, JT Li, WJ Chakraborty, I Shcheglov, K Wilcox, JZ Kaiser, WJ AF Tang, TK Gutierrez, RC Stell, CB Vorperian, V Arakaki, GA Rice, JT Li, WJ Chakraborty, I Shcheglov, K Wilcox, JZ Kaiser, WJ GP IEEE TI A packaged silicon MEMS vibratory gyroscope for microspacecraft SO MEMS 97, PROCEEDINGS - IEEE THE TENTH ANNUAL INTERNATIONAL WORKSHOP ON MICRO ELECTRO MECHANICAL SYSTEMS: AN INVESTIGATION OF MICRO STRUCTURES, SENSORS, ACTUATORS, MACHINES AND ROBOTS SE PROCEEDINGS: IEEE MICRO ELECTRO MECHANICAL SYSTEMS WORKSHOP LA English DT Proceedings Paper CT IEEE 10th Annual International Workshop on Micro Electro Mechanical Systems CY JAN 26-30, 1997 CL NAGOYA, JAPAN SP IEEE Robot & Automat Soc, ASME Dynam Syst & Control Div, ASME Micromachine Ctr AB In this paper, we present recent work on the design, fabrication, and packaging of a silicon Micro-Electro-Mechanical System (MEMS) microgyroscope designed for space applications. A hermetically sealed package that houses the microgyroscope and most of its control electronics has been built and tested. The entire microgyroscope package is approximately 1 x 1 x 0.7 inches in dimensions. The rest of the control electronics which includes the drive and lock-in amplifier circuitry are mounted outside the gyro box on a 1 x 1 inch circuit board. This packaged microgyroscope has a 7 Hz split between its drive and sense mode and has a scale factor of 24mV/deg/sec, bias stability of 70 deg/hr, angle random walk of 6.3 deg/root hr, and a rate ramp of 0.2 deg/hr/sec. Recent improvements on the fabrication and assembly procedures and microgyroscope design have resulted in clover-leaf structures with matched drive and sense resonant frequency. These new structures have a very small temperature dependent frequency shift of 0.23 Hz/degree for both the drive and sense modes. RP Tang, TK (reprint author), CALTECH,JET PROP LAB,MICRODEVICES LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Li, Wen Jung/M-9995-2013 OI Li, Wen Jung/0000-0001-9616-6213 NR 0 TC 34 Z9 35 U1 0 U2 4 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1084-6999 BN 0-7803-3745-X J9 PROC IEEE MICR ELECT PY 1997 BP 500 EP 505 DI 10.1109/MEMSYS.1997.581911 PG 6 WC Automation & Control Systems; Engineering, Multidisciplinary; Engineering, Electrical & Electronic; Engineering, Mechanical SC Automation & Control Systems; Engineering GA BH55X UT WOS:A1997BH55X00088 ER PT J AU Zolensky, ME AF Zolensky, ME TI Structural water in the Bench Crater chondrite returned from the Moon SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID SEMARKONA AB I have reinvestigated the mineralogy of the only carbonaceous chondrite (12037,188) returned from the Moon and found saponite within, which comprises the first hydrous material returned from the Moon. That this phyllosilicate has survived impact onto the lunar surface suggests that asteroid and cometary impacts could have provided significant quantities of surviving clay (hydrous) minerals into the lunar regolith. The Bench Crater meteorite also provides a glimpse of the petrography of the ancient meteoroid complex, something not possible on the geologically active Earth. RP Zolensky, ME (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, EARTH SCI & SOLAR SYST EXPLORAT DIV, HOUSTON, TX 77058 USA. NR 24 TC 29 Z9 29 U1 0 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 1997 VL 32 IS 1 BP 15 EP 18 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XK171 UT WOS:A1997XK17100008 ER PT J AU McCoy, TJ Ehlmann, AJ Moore, CB AF McCoy, TJ Ehlmann, AJ Moore, CB TI The Leedey, Oklahoma, chondrite: Fall, petrology, chemistry and an unusual Fe,Ni-FeS inclusion SO METEORITICS & PLANETARY SCIENCE LA English DT Article AB The Leedey, Oklahoma, meteorite shower fell on 1943 November 25, following a fireball which was visible across much of southwestern Oklahoma and northcentral Texas. The shower produced 24 stones with a total mass of similar to 51.5 kg. The stones formed a strewnfield similar to 18 km in length in the same direction as the observed path of the meteor (N50 degrees W). Leedey is classified as an L6(S3) ordinary chondrite. We report bulk major element chemical analyses from four separate laboratories. Leedey contains an unusual 6 by 8 mm composite Fe,Ni-FeS grain, which is composed of a 3 mm kamacite grain adjacent to a 5 mm troilite grain. A 50-100 mu m rim of high-Ni (45-55 wt%) taenite (tetrataenite) occurs at the boundary between kamacite and troilite. A single, zoned pyrophanite grain is observed at the boundary between the inclusion troilite and host silicates. An origin as a foreign particle incorporated after metamorphism or during impact melting appears unlikely. This particle likely formed by a complex set of processes, including melting in the nebula, parent body metamorphism and reheating by later shock, mirroring the history of the host chondrite. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. TEXAS CHRISTIAN UNIV,DEPT GEOL,FT WORTH,TX 76129. ARIZONA STATE UNIV,CTR METEORITE STUDIES,TEMPE,AZ 85287. NR 25 TC 4 Z9 4 U1 0 U2 3 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 1997 VL 32 IS 1 BP 19 EP 24 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XK171 UT WOS:A1997XK17100009 ER PT J AU Krot, AN Scott, ERD Zolensky, ME AF Krot, AN Scott, ERD Zolensky, ME TI Origin of fayalitic olivine rims and lath-shaped matrix olivine in the CV3 chondrite Allende and its dark inclusions SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID UNEQUILIBRATED ORDINARY CHONDRITES; AQUEOUS ALTERATION; CARBONACEOUS CHONDRITES; PARENT BODY; OXYGEN ISOTOPES; MINERALOGY; METEORITES; COMPONENTS; VIGARANO; HISTORY AB We have studied an Allende dark inclusion by optical microscopy, scanning electron microscopy, electron microprobe analysis and transmission electron microscopy. The inclusion consists of chondrules, isolated olivines and matrix, which, as in the Allende host, is mainly composed of 5-20 mu m long lath-shaped fayalitic grains with a narrow compositional range (Fa(42 +/- 2)) and nepheline. Olivine phenocrysts in chondrules and isolated olivine grains show various degrees of replacement by 5-10 mu m wide fayalitic rims (Fa(39 +/- 2)) and 100-1000 mu m wide translucent zones, which consist of 5-20 mu m long lath-shaped fayalitic grains (Fa(41 +/- 1)) intergrown with nepheline. These fayalitic olivines, like those in the matrix of the dark inclusion, contain 10-20 nm sized inclusions of chromite, hercynite, and Fe-Ni sulfides. The fayalitic rims around remnant olivines are texturally and compositionally identical to those in Allende host, suggesting that they have similar origins. Chondrules are surrounded by opaque rims consisting of tiny lath-shaped fayalitic olivines (<1-3 mu m long) intergrown with nepheline. As in the Allende host, fayalitic olivine veins may crosscut altered chondrules, fine-grained chondrule rims and extend into the matrix, indicating that alteration occurred after accretion. We infer that fayalitic olivine rims and lath-shaped fayalites in Allende and its dark inclusions formed from phyllosilicate intermediate phases. This explanation accounts for (1) the similarity of the replacement textures observed in the dark inclusion and Allende host to aqueous alteration textures in CM chondrites; (2) the anomalously high abundances of Al and Cr and the presence of tiny inclusions of spinels and sulfides in fayalitic olivines in Allende and Allende dark inclusions; (3) abundant voids and defects in lath-shaped fayalites in the Allende dark inclusion, which may be analogous to those in partly dehydrated phyllosilicates in metamorphosed CM/CI chondrites. We conclude that the matrix and chondrule rims in Allende were largely converted to phyllosilicates and then completely dehydrated. The Allende dark inclusions experienced diverse degrees of aqueous/hydrothermal alteration prior to complete dehydration. The absence of low-Ca pyroxene in the dark inclusion and its significant replacement by fayalitic olivine in Allende is consistent with the lower resistance of low-Ca pyroxene to aqueous alteration relative to forsteritic olivine. Hydrothermal processing of Allende probably also accounts for the low abundance of planetary noble gases and interstellar grains, and the formation of nepheline, sodalite, salite-hedenbergite pyroxenes, wollastonite, kirschsteinite and andradite in chondrules and Ca,Al-rich inclusions. C1 NASA,LYNDON B JOHNSON SPACE CTR,EARTH SCI & SOLAR SYST EXPLORAT DIV,HOUSTON,TX 77058. RP Krot, AN (reprint author), UNIV HAWAII MANOA,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822, USA. NR 77 TC 89 Z9 90 U1 0 U2 6 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 1997 VL 32 IS 1 BP 31 EP 49 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XK171 UT WOS:A1997XK17100011 ER PT J AU Hartmann, WK Gaskell, RW AF Hartmann, WK Gaskell, RW TI Planetary cratering 2: Studies of saturation equilibrium SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID SOLAR-SYSTEM; VOYAGER-2; DISTRIBUTIONS; ENCOUNTER; JUPITER; RECORD; SATURN AB A realistic computer model has been developed to display images of imaginary cratered surfaces, taking into account empirically measured input size distributions of primary and secondary craters, ejecta blanket morphology including feathering with distance, obliteration due to ejecta from outside the imaged area, lighting effects, etc. The model allows us to track surface evolution of morphology as new craters are added. Using the model as well as lunar photos, we have studied the approach to saturation equilibrium (defined as a condition when no further proportionate increase in crater density occurs as input cratering increases). We find that an identifiable saturation equilibrium occurs close to a level previously identified for this state (Hartmann, 1984), typically fluctuating around a crater density from similar to 0.4 to 2 times that level. This result is fairly robust vis-ir-vis the range of model parameters we have chosen. Flooding, basin ejecta blankets, and other obliterative effects can introduce structure and oscillations within this range, even after saturation equilibrium is achieved. These findings may constrain or revise certain earlier interpretations of satellite and planet surface evolution and impactor populations, which were predicated on the assumed absence of saturation equilibrium. In our fourth experimental run, we found that suppression of ''sandblasting'' by subresolution impacts allows the smallest secondaries to rise above the saturation equilibrium line, a result that might be relevant to a similar situation on Gaspra and perhaps some other asteroids. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Hartmann, WK (reprint author), SJI,PLANETARY SCI INST,620 N 6TH AVE,TUCSON,AZ 85705, USA. NR 36 TC 31 Z9 33 U1 0 U2 3 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JAN PY 1997 VL 32 IS 1 BP 109 EP 121 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA XK171 UT WOS:A1997XK17100019 ER PT J AU Ellison, J Ahmadi, G Grodsinsky, C AF Ellison, J Ahmadi, G Grodsinsky, C TI Stochastic response of passive vibration control systems to g-jitter excitation SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID EARTHQUAKE RESPONSE; SPECTRA; MODEL AB Passive and active vibration control strategies are used to reduce the g-jitter experienced by the equipment and their subsystems aboard spacecraft and space stations. Designing the optimal mechanism involves the evaluation of the dynamic response of the system under a variety of conditions, The g-jitter excitations are generally random and exhibit non-deterministic variations in amplitude and frequency content. Here, a probabilistic approach is used to evaluate the equipment and secondary system responses for passive vibration control mechanisms as compared to a fixed-base condition. The stochastic model for the STS-40 orbital acceleration is used for the spacecraft excitation. The method of moment of Fokker-Planck equation and time-dependent equivalent linearization in conjunction with expansion by normal modes are employed to compute the mean-square response statistics of a shear beam structure. The fixed-base condition and the equipment with a passive vibration control mechanism are analyzed. The Monte-Carlo simulations are also performed to compute the response statistics of various systems. It is shown that the mean-square responses obtained from the moment method are in good agreement with the Monte-Carlo simulation results except for the pure friction vibration control system. The results also show that the passive control devices are highly effective in reducing the peak responses of the equipment and their subsystems. Furthermore, the statistical response spectra provide reasonable upper bounds on peak equipment and the secondary system responses. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Ellison, J (reprint author), CLARKSON UNIV,DEPT MECH & AERONAUT ENGN,POTSDAM,NY 13699, USA. NR 29 TC 6 Z9 7 U1 0 U2 1 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 860420, W-8163 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PY 1997 VL 10 IS 1 BP 2 EP 12 PG 11 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA YG317 UT WOS:A1997YG31700001 ER PT J AU Vander Wal, RL AF Vander Wal, RL TI Laser-induced incandescence measurements in low-gravity SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID HYDROCARBON DIFFUSION FLAMES; SOOT-VOLUME FRACTION; TEMPERATURE; COMBUSTION; BUOYANCY; BEHAVIOR AB A low-gravity environment offers advantages to investigations concerned with soot growth or flame radiation by eliminating of buoyancy-induced convection. Basic to each type of study is knowledge of spatially resolved soot volume fraction (f(v)). Laser-induced incandescence (LII) has emerged as a diagnostic for soot volume fraction determination because it possesses high temporal and spatial resolution, geometric versatility and high sensitivity. Implementation and system characterization of LII in a drop tower that provides 2.2 s of low-gravity (mu g) at the NASA Lewis Research Center are describe here. Validation of LII for soot volume fraction determination in mu g is performed by comparison between soot volume fraction measurements obtained by light extinction and LII in low-gravity for laminar gas-jet diffusion flames consisting of a 50/50-mixture (by volume) of acetylene/nitrogen issuing into quiescent air. Quantitative soot volume fraction measurements within other laminar flames of ethane and propane and a turbulent diffusion flame in mu g via LII are also demonstrated. An analysis of LII images of a turbulent acetylene diffusion flame in 1 g and mu g is presented. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA, Lewis Res Ctr, 110-3,21000 Brookpark Rd, Cleveland, OH 44135 USA. EM randy@rvander.lerc.nasa.gov NR 38 TC 6 Z9 6 U1 0 U2 2 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PY 1997 VL 10 IS 2 BP 66 EP 74 PG 9 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA ZP893 UT WOS:000073799200001 ER PT J AU Miller, TL Leslie, FW AF Miller, TL Leslie, FW TI Microgravity experiments and numerical modeling of rotating buoyant convection in a spherical shell with latitudinal thermal gradients SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID FLUID SHELL; INSTABILITIES; SIMULATIONS; ANNULUS; NUMBER; FLOWS; ONSET AB The results of numerical model calculations are compared with space laboratory experiments for rotating, thermally driven flow in a hemispherical shell, and various flow regimes are described. A spherically symmetric body force, analogous to gravity, is imposed in the radial direction through the use of a dielectric fluid and an electrostatic potential difference across the gap. The spherical boundaries ave maintained at constant temperature profiles (with the pole and the inner sphere being the warmer surfaces), and the equatorial wall is an insulator. Typical parameter combinations result in highly nonlinear, but laminar, flow. For weak enough buoyant forcing, the flow is axisymmetric. It consists of a single meridional cell, rising in warm latitudes (in this case, near the pole) and sinking in cool latitudes, with prograde flow in the equatorial region and near the inner hemisphere for other latitudes, and retrograde motion elsewhere. For fast rotation, the first transition due to the instability of this simple flow is also axisymmetric, consisting of rings of convection in the polar region, which propagate poleward. The first non-axisymmetric convection occurs at Rayleigh numbers which increase with rotation rate. The form of the convection near the transition also depends upon the rate of rotation. Selected flow patterns near the transition as well as those beyond it are studied numerically. For those cases where there exist laboratory experiments with which to compare, the numerical and experimental results agree very well. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Miller, TL (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Code HR20, Huntsville, AL 35812 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PY 1997 VL 10 IS 4 BP 197 EP 209 PG 13 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA 128ZD UT WOS:000076437500005 ER PT J AU Mazuruk, K Ramachandran, N AF Mazuruk, K Ramachandran, N TI Convection in an infinite vertical cylinder in the presence of a horizontal magnetic field SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID CRYSTAL-GROWTH; CZOCHRALSKI AB The use of a magnetic field to suppress convection in low gravity materials processing is an area of active research. This study aims ta investigate some of the basic features of an imposed transverse magnetic field on convective motion in electrically conducting melts. The geometry considered is an infinite vertical column of liquid metal with an axial temperature gradient and an imposed transverse magnetic field. The incipience and azimuthal orientation of convective rolls is investigated. The governing transport equations are non-dimensionalized, linearized, and the eigen-value problem is solved to determine the most physically significant states. The analysis shows that the initial degeneracy (with no magnetic field) is removed by the presence of a magnetic field and the primary convection roll aligns itself so that ifs plane is perpendicular to the applied magnetic field. Velocity distributions are presented corresponding to the lowest modes. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Space Sci Lab ES75, Huntsville, AL 35812 USA. RP Mazuruk, K (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Space Sci Lab ES75, Huntsville, AL 35812 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 86 04 20, D-81679 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PY 1997 VL 10 IS 4 BP 210 EP 217 PG 8 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA 128ZD UT WOS:000076437500006 ER PT B AU Tang, WC AF Tang, WC BE Chau, K French, PJ TI MEMS applications in space exploration SO MICROMACHINED DEVICES AND COMPONENTS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd Conference on Micromachined Devices and Components CY SEP 29, 1997 CL AUSTIN, TX SP Soc Photo Opt Instrumentat Engineers, Semiconductor Equipment & Mat Int, NIST, Solid State Technol DE MEMS; micro; electro; mechanical; systems; space applications; technology; reliability; overview AB Space exploration in the coming century will emphasize cost effectiveness and highly focused mission objectives, which will result in frequent multiple missions that broaden the scope of space science and to validate new technologies on a timely basis. Micro Electro Mechanical Systems (MEMS) is one of the key enabling technology to create cost-effective, ultra-miniaturized, robust, and functionally focused spacecraft for both robotic and human exploration programs. Examples of MEMS devices at various stages of development include microgyroscope, microseismometer, microhygrometer, quadrupole mass spectrometer, and micropropulsion engine. These devices, when proven successful, will serve as models for developing components and systems for new-millennium spacecraft. RP Tang, WC (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2656-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3224 BP 202 EP 211 DI 10.1117/12.284517 PG 10 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Optics SC Engineering; Optics GA BJ87J UT WOS:A1997BJ87J00022 ER PT S AU Justus, CG Johnson, DL AF Justus, CG Johnson, DL BE Grossmann, KU Riese, M Clemesha, BR TI The GRAM model: Status of development and future aspects SO MIDDLE AND UPPER ATMOSPHERES: SMALL SCALE STRUCTURES AND REMOTE SENSING SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT C1-2 and C1-3 Symposia of COSPAR Scientific Commission C on Middle and Upper Atmospheres - Small Scale Structures and Remote Sensing, at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Comm Space Res, Sci Comm Solar Terrestrial Phys AB The NASA Marshall Space Flight Center's Global Reference Atmospheric Model has been updated to a 1995 version (GRAM-95). GRAM-95 has a middle atmosphere (20 to 120 km) climatology based on extensive summaries from Middle Atmosphere Program (MAP) data. GRAM-95 also updates the lower altitude (0 - 27 km) region with Global Upper Air Climatic Atlas (GUACA) data (based on a climatology of European Center for Medium-Range Weather Forecasting (ECMWF) data). Like earlier versions, GRAM-95 includes global-scale, monthly-mean values for temperature, density, pressure, and wind components at all altitudes. Based primarily on MAP species concentration climatologies, GRAM-95 now includes estimates for water vapor and other species (including O-3, N2O, CO, CH4, CO2, N-2, O-2, O, A, He, and H). A revised perturbation model in GRAM-95 simulates the statistical characteristics of both small-scale and large-scale processes, including variations of thermodynamic properties and wind components. Example outputs are presented and possible future developments are summarized. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, HUNTSVILLE, AL 35812 USA. RP COMP SCI CORP, POB 240005, HUNTSVILLE, AL 35824 USA. NR 19 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043104-6 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 4 BP 549 EP 558 DI 10.1016/S0273-1177(97)00170-1 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BH89M UT WOS:A1997BH89M00001 ER PT S AU Bittner, M Offermann, D Preusse, P Riese, M Claude, H Schmidlin, FJ AF Bittner, M Offermann, D Preusse, P Riese, M Claude, H Schmidlin, FJ BE Grossmann, KU Riese, M Clemesha, BR TI CRISTA ozone measurements/validation SO MIDDLE AND UPPER ATMOSPHERES: SMALL SCALE STRUCTURES AND REMOTE SENSING SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT C1-2 and C1-3 Symposia of COSPAR Scientific Commission C on Middle and Upper Atmospheres - Small Scale Structures and Remote Sensing, at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Comm Space Res, Sci Comm Solar Terrestrial Phys AB Seven days of global high resolution middle atmosphere ozone profiles have been measured by the CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) in November 1994. Measurements cover the altitude range from 10 to 80 km and latitudes from 59 degrees S to 64 degrees N. An example of a global ozone map is presented and demonstrates the ability of the instrument to detect medium and even small scale structures. Comparisons with ECC- and Brewer Mast balloon-sonde underflights are discussed. Reasonable agreement between CRISTA and balloon-sondes is found especially in the altitude interval between about 19 km and 27 km. (C) 1997 COSPAR. C1 DEUTSCH WETTERDIENST, D-82383 HOHENPEISSENBERG, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, OBSERVAT SCI BRANCH, WALLOPS ISL, VA 23337 USA. RP BERG UNIV GESAMTHSCH WUPPERTAL, DEPT PHYS, GAUSS STR 20, D-42097 WUPPERTAL, GERMANY. RI Preusse, Peter/A-1193-2013; Riese, Martin/A-3927-2013 OI Preusse, Peter/0000-0002-8997-4965; Riese, Martin/0000-0001-6398-6493 NR 7 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043104-6 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 4 BP 567 EP 570 DI 10.1016/S0273-1177(97)00173-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BH89M UT WOS:A1997BH89M00004 ER PT J AU Farmer, CB AF Farmer, CB TI Stratospheric FTS SO MIKROCHIMICA ACTA LA English DT Article; Proceedings Paper CT 10th International Conference on Fourier Transform Spectroscopy (ICOFTS) CY AUG 27-SEP 01, 1995 CL BUDAPEST, HUNGARY SP Fed Eur Chem Soc, Hung Acad Sci, Working Comm Laser Phys Spectro HAS, Minist Cult Educ Hungary, Austrian Soc Anal Chem, Hung Nat Comm Technol Develop, Inst Isotopes HAS, Univ Veszprem, Central Res Inst Chem HAS DE atmospheric environment; atmospheric contaminants; ozone loss; halogen compounds; nitrogen oxides; FT spectroscopy ID TRACE GASES; CHLORINE; OZONE AB Fourier-transform spectroscopy has played a prominent role over the past quarter century in Furthering our understanding of the properties of the upper atmosphere and, in particular, in elucidating the processes that control the chemical and dynamical stability of the stratosphere. The first detections of HCl and HF in the early 1970s led to the discovery of the discrimination between anthropogenic and natural emissions of halogens which the changing ratio of these two trace compounds provided. More recently, the comparison, against model predictions of refined and revised measurements of the altitude-dependent budgets of the source and reservoir components of the chlorine, fluorine and nitrogen families of trace molecular species, has formed the basis of well-constrained rests against which the effectiveness of international protocols to control the release of industrial chemicals can be assessed. The contribution of the FTS methods to these and other global atmospheric environmental problems has been invaluable. Experimentalists have responded to the challenge of adapting Fourier-transform techniques to the often difficult environments of spacecraft, balloon, aircraft or remote ground-based sites in order to exploit the advantages afforded by making observations from these platforms. These developments and the current status of the results obtained from them are described. RP Farmer, CB (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0026-3672 J9 MIKROCHIM ACTA JI Mikrochim. Acta PY 1997 SU 14 BP 89 EP 101 PG 13 WC Chemistry, Analytical SC Chemistry GA WW404 UT WOS:A1997WW40400012 ER PT S AU Liceaga, CA Troutman, PA AF Liceaga, CA Troutman, PA BE Chinni, MJ TI A functional simulator of spacecraft resources SO MILITARY, GOVERNMENT, AND AEROSPACE SIMULATION SE SIMULATION SERIES LA English DT Proceedings Paper CT 1997 Simulation MultiConference on Military, Government, and Aerospace Simulation CY APR 06-10, 1997 CL ATLANTA, GA SP Soc Comp Simulat Int DE aerospace; computer-aided design; resource management; continuous simulation; and system analysis AB The SPAcecraft: SIMulator (SPASIM) simulates the functions and resources of a spacecraft to quickly perform Phase A trade-off analyses and uncover any operational bottlenecks during any part of the mission. Failure modes and operational contingencies can be evaluated allowing optimization for a range of mission scenarios. The payloads and subsystems are simulated, using a hierarchy of graphical models, in terms of how their functions affect resources such as propellant, power, and data. Any of the inputs and outputs of the payloads and subsystems can be plotted during the simulation. Most trade-off analyses, including those that compare current versus advanced technology, can be performed by changing values in the parameter menus. However, when a component is replaced by one with a different functional architecture, its graphical model can also be modified or replaced by drawing from a component library. SPASIM has been validated using several spacecraft designs which were at least at the Critical Design Review level. The user and programmer guide, including figures, is available on line as a hyper text document. This is an easy-to-use and expand tool which is based on MATLAB(R) and SIMULINK(R). It runs on SGI workstations and PCs under Windows 95(R) or NT(R). C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Liceaga, CA (reprint author), NASA, Langley Res Ctr, 8 Langley Blvd,M-S 328, Hampton, VA 23681 USA. NR 2 TC 0 Z9 0 U1 1 U2 2 PU SOC COMPUTER SIMULATION PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92177 USA SN 0735-9276 BN 1-56555-120-6 J9 SIMUL SERIES PY 1997 VL 29 IS 4 BP 115 EP 120 PG 6 WC Engineering, Aerospace; Computer Science, Software Engineering SC Engineering; Computer Science GA BQ03P UT WOS:000086918900019 ER PT B AU Krishen, K Kachroo, P AF Krishen, K Kachroo, P BE Kenyon, CH Kachroo, P TI Sensor requirements for control systems with an example of longitudinal headway control of vehicles in automated highway systems SO MOBILE ROBOTS XI AND AUTOMATED VEHICLE CONTROL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Mobile Robots XI and Automated Vehicle Control Systems CY NOV 20-21, 1996 CL BOSTON, MA SP Soc Photo Opt Instrumentat Engineers DE sensors; automated; highway; system; feedback; control; requirements AB There is a need for developing a methodology for obtaining sensor requirements for control systems. This study is an attempt at developing a methodology for specifying sensor needs as part of the design process of dynamic control systems in general, and Automated Highway System (AHS) in particular. Such approaches have not been advanced to-date. The current practice is to assume sensor parameters from available sensors and devise control strategies. That does not in general produce optimal designs. This paper provides a discussion on the sensor requirements needed for longitudinal headway control of vehicles in an AHS. RP Krishen, K (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,TECHNOL TRANSFER & COMMERCIALIZAT OFF,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2305-X J9 P SOC PHOTO-OPT INS PY 1997 VL 2903 BP 75 EP 85 DI 10.1117/12.265350 PG 11 WC Automation & Control Systems; Optics SC Automation & Control Systems; Optics GA BH22E UT WOS:A1997BH22E00008 ER PT S AU Tielens, AGGM Whittet, DCB AF Tielens, AGGM Whittet, DCB BE vanDishoeck, EF TI Ices in star forming regions SO MOLECULES IN ASTROPHYSICS: PROBES AND PROCESSES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 178th Symposium of the International-Astronomical-Union on Molecules in Astrophysics - Probes and Processes CY JUL 01-05, 1996 CL LEIDEN, NETHERLANDS SP Int Astron Union ID ABSORPTION FEATURES; GRAIN MANTLES; SOLID CO; INFRARED-SPECTROSCOPY; EXPLOSIVE DESORPTION; INTERSTELLAR ICES; MOLECULAR CLOUDS; DENSE CLOUDS; METHANOL; PROTOSTARS AB IR spectra of sources associated with molecular cloud material show a variety of absorption features attributed to simple molecules, such as H2O, CO, CH3OH, CO2, CH4, and OCS in icy grain mantles. These identifications are reviewed. These molecules are formed through accretion and reaction of gas phase species on grain surfaces. The high abundance of CH3OH and CO2 point towards the importance of hydrogenation and oxidation reactions in this process. Observations also show that thermal outgassing is of great importance for the composition of interstellar ice mantles. Both these processes are discussed in some detail. C1 RENSSELAER POLYTECH INST, DEPT PHYS APPL PHYS & ASTRON, TROY, NY 12180 USA. RP Tielens, AGGM (reprint author), NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 53 TC 28 Z9 28 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4538-X J9 IAU SYMP PY 1997 IS 178 BP 45 EP 60 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ12H UT WOS:A1997BJ12H00005 ER PT S AU Langhoff, SR Schwenke, DW Partridge, H AF Langhoff, SR Schwenke, DW Partridge, H BE vanDishoeck, EF TI Determination of opacity data bases for TiO and H2O SO MOLECULES IN ASTROPHYSICS: PROBES AND PROCESSES SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 178th Symposium of the International-Astronomical-Union on Molecules in Astrophysics - Probes and Processes CY JUL 01-05, 1996 CL LEIDEN, NETHERLANDS SP Int Astron Union ID BASIS-SETS; STATES; TEMPERATURE; LIFETIME AB Current ab initio methods for determining potential energy surfaces are discussed in relation to the TiO and H2O molecules, both of which make important contributions to the opacity of M-type stars. For the TiO molecule we discuss the determination of the radiative lifetimes of the excited states and band oscillator strengths for both the triplet and singlet band systems. While the theoretical radiative lifetimes for TiO agree well with recent measurements, the band oscillator strengths differ significantly from those currently employed in opacity calculations. For the H2O molecule we discuss the current results for the ground state potential energy and dipole moment surfaces generated at NASA Ames. We show that it is necessary to account for such effects as core-valence correlation to generate a potential energy surface of near spectroscopic accuracy. The current status of our effort to establish opacity data bases for both TiO and H2O is described. RP Langhoff, SR (reprint author), NASA, AMES RES CTR, MAIL STOP 230-3, MOFFETT FIELD, CA 94035 USA. RI schwenke, david/I-3564-2013 NR 23 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4538-X J9 IAU SYMP PY 1997 IS 178 BP 295 EP 303 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ12H UT WOS:A1997BJ12H00026 ER PT J AU Gladders, MD Abraham, RG McHardy, IM Crawford, CS Merrifield, MR Jones, LR AF Gladders, MD Abraham, RG McHardy, IM Crawford, CS Merrifield, MR Jones, LR TI The optical structure and local environment of the BL Lac object 1E 1415.6+2557 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies, active; BL Lacertae objects, individual, 1E 1415.6+2557; galaxies, clusters, general ID LACERTAE OBJECTS; RADIO GALAXIES; CLUSTER ENVIRONMENTS; SURFACE PHOTOMETRY; COMPLETE SAMPLE; HOST GALAXIES; PKS 0521-36; JET; POLARIZATION; PKS-1413+135 AB The X-ray-selected BL Lac object 1E 1415.6 + 2557 is of current interest, because its host galaxy morphology and clustering environment appear to be inconsistent with standard beaming models for BL Lac objects. The host galaxy of 1E 1415.6 + 2557 was originally identified as a luminous spiral galaxy, but more recently this galaxy has been classified as an isolated giant elliptical galaxy with an optical jet. We present deep multicolour high-resolution optical images of this object, and confirm that the host galaxy is a giant elliptical galaxy. We find that the optical 'jet' is more likely to be an inclined spiral galaxy seen in projection against the BL Lac object, or a nearby companion galaxy. We also present evidence that 1E 1415.6 + 2557 resides in a compact group or a poor (Abel class 0) cluster of galaxies. These results are consistent with unification models in which BL Lac objects are low-luminosity radio galaxies seen at a small angle to the line of sight of a relativistic jet. C1 NATL RES COUNCIL CANADA,DOMINION ASTROPHYS OBSERV,VICTORIA,BC V8X 4M6,CANADA. UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. UNIV SOUTHAMPTON,DEPT PHYS,SOUTHAMPTON SO17 1BJ,HANTS,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Gladders, MD (reprint author), UNIV VICTORIA,DEPT PHYS & ASTRON,POB 3055,VICTORIA,BC V8W 3P6,CANADA. NR 38 TC 3 Z9 3 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 1 PY 1997 VL 284 IS 1 BP 27 EP 31 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA853 UT WOS:A1997WA85300003 ER PT J AU Meyyappan, M AF Meyyappan, M TI Characteristic of an electron cyclotron resonance plasma source for the production of active nitrogen species in III-V nitride epitaxy SO MRS INTERNET JOURNAL OF NITRIDE SEMICONDUCTOR RESEARCH LA English DT Article AB A simple analysis is provided to determine the characteristics of an electron cyclotron resonance (ECR) plasma source for the generation of active nitrogen species in the molecular beam epitaxy of III-V nitrides. The effects of reactor geometry, pressure, power, and flow rate on the dissociation efficiency and ion flux are presented. Pulsing the input power is proposed to reduce the ion flux. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Meyyappan, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 1092-5783 J9 MRS INTERNET J N S R JI Mrs. Internet J. Nitride Semicond. Res. PY 1997 VL 2 IS 42-45 BP art. no. EP 46 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA YB214 UT WOS:A1997YB21400005 ER PT S AU Bartolotta, PA Ellis, JR AbdulAziz, A AF Bartolotta, PA Ellis, JR AbdulAziz, A BE Kalluri, S Bonacuse, PJ TI A structural test facility for in-plane biaxial testing of advanced materials SO MULTIAXIAL FATIGUE AND DEFORMATION TESTING TECHNIQUES SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Multiaxial Fatigue and Deformation Testing Techniques CY MAY 15, 1995 CL DENVER, CO SP Amer Soc Testing & Mat, Comm Fatigue & Fracture DE in-plane biaxial loading; advanced materials; radiant quartz lamp heating; automated microscope; environmental chamber; metal-matrix composites; ceramic-matrix composites; polymer-matrix composites; crack growth measurements; fatigue (materials); fracture (materials; testing; deformation (materials); multiaxial fatigue AB A benchmark structural testing facility has been established at the NASA Lewis Research Center (NASA/LeRC). The primary function of this facility is to verify structural analysis methods under prototypical loading conditions. Further, the facility allows the structural integrity of advanced monolithic and composite materials to be evaluated in subelement form. The intent is to bridge the gap that frequently exists between coupon level response and full-scale component response by conducting tests on subscale structures that have relatively simple geometries (that is, plates, beams, etc.). Unlike actual components, these subelement structures can be mechanically loaded and heated in a controlled and precise manner leading to reliable data. As a first step in this research, two in-plane biaxial plate test systems were recently installed at NASA/LeRC. This paper describes one of these test systems that consists of a 500-kN load frame with four hydraulic actuators, a state-of-the-art digital controller and innovative control software, an advanced quartz lamp radiant furnace, a large environmental chamber, and an automated in-situ crack measurement system. RP Bartolotta, PA (reprint author), NASA,LEWIS RES CTR,STRUCT FATIGUE BRANCH,CLEVELAND,OH 44135, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 SN 1071-5827 BN 0-8031-2045-1 J9 AM SOC TEST MATER PY 1997 VL 1280 BP 25 EP 42 DI 10.1520/STP16211S PG 18 WC Mechanics; Materials Science, Characterization & Testing SC Mechanics; Materials Science GA BH07U UT WOS:A1997BH07U00002 ER PT S AU Ellis, JR Bartolotta, PA AF Ellis, JR Bartolotta, PA BE Kalluri, S Bonacuse, PJ TI Adjustable work coil fixture facilitating the use of induction heating in mechanical testing SO MULTIAXIAL FATIGUE AND DEFORMATION TESTING TECHNIQUES SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Multiaxial Fatigue and Deformation Testing Techniques CY MAY 15, 1995 CL DENVER, CO SP Amer Soc Testing & Mat, Comm Fatigue & Fracture DE induction heating; mechanical testing; adjustable fixturing; closely controlled thermal gradients; specimen barreling; thermomechanical database; Hastelloy X; fatigue (materials); fracture (materials); testing; deformation (materials); multiaxial fatigue AB Induction heating has been used in fatigue testing for over 30 years. Typically, a work coil is used in conjunction with a workstation and a radio frequency power supply to provide localized specimen heating. One disadvantage of the approach is that the localized nature of the heating leads to temperature gradients over the specimen's length. However, experience has shown that the configuration of work coils can be optimized to give relatively uniform temperature profiles over the specimen's gage section. The variables of interest include: coil diameter and overall length, number of turns, spacing of turns, and grouping of turns. Optimization of these variables by trial and error can be a lengthy and frustrating process. This is particularly the case in multiaxial experiments involving large tubular specimens and correspondingly large work coils. The subject work coil fixture was designed and developed to facilitate the optimization process. The approach adopted was to subdivide the work coil into three segments. Each segment has its own positioning mechanism that allows independent adjustment in both the radial and vertical senses. It was shown that use of this fixture allows temperature profiles within +/-1% of the mean to be achieved with minimum difficulty. Such levels of precision were found to be necessary in a recent series of thermomechanical experiments conducted on Hastelloy X. RP Ellis, JR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 5 Z9 5 U1 1 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 SN 1071-5827 BN 0-8031-2045-1 J9 AM SOC TEST MATER PY 1997 VL 1280 BP 43 EP 62 DI 10.1520/STP16212S PG 20 WC Mechanics; Materials Science, Characterization & Testing SC Mechanics; Materials Science GA BH07U UT WOS:A1997BH07U00003 ER PT S AU Kalluri, S Bonacuse, PJ AF Kalluri, S Bonacuse, PJ BE Kalluri, S Bonacuse, PJ TI An axial-torsional, thermomechanical fatigue testing technique SO MULTIAXIAL FATIGUE AND DEFORMATION TESTING TECHNIQUES SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Multiaxial Fatigue and Deformation Testing Techniques CY MAY 15, 1995 CL DENVER, CO SP Amer Soc Testing & Mat, Comm Fatigue & Fracture DE thermomechanical fatigue; axial-torsional fatigue; computer-controlled testing; data acquisition; thin-walled tubular specimen; testing techniques; hysteresis loop; cyclic deformation; cobalt-base superalloy; fatigue (materials); fracture (materials); testing; deformation (materials); multiaxial fatigue AB A technique for conducting strain-controlled, thermochemical, axial-torsional fatigue tests on thin-walled tubular specimens was developed. Three waveforms of loading, namely, the axial strain waveform, the engineering shear strain waveform, and the temperature waveform were required in these tests. The phasing relationships between the mechanical strain waveforms and the temperature and axial strain waveforms were used to define a set of four axial-torsional, thermomechanical fatigue (AT-TMF) tests. Real-time test control(three channels) and data acquisition (a minimum of seven channels) were performed with a software program written in C language and executed on a personal computer. The AT-TMF testing technique was used to investigate the axial-torsional thermomechanical fatigue behavior of a cobalt-base superalloy, Haynes 188. The maximum and minimum temperatures selected for the AT-TMF tests were 760 and 316 degrees C, respectively. Details of the testing system, calibration of the dynamic temperature profile of the thin-walled tubular specimen, thermal strain compensation technique, and test control and data acquisition schemes, are reported. The isothermal, axial, torsional, and in- and out-of-phase axial-torsional fatigue behaviors of Haynes 188 at 316 and 760 degrees C were characterized in previous investigations. The cyclic deformation and fatigue behaviors of Haynes 188 in AT-TMF tests are compared to the previously reported isothermal axial-torsional behavior of this superalloy at the maximum and minimum temperatures. RP Kalluri, S (reprint author), NASA,LEWIS RES CTR,NYMA INC,CLEVELAND,OH 44135, USA. NR 0 TC 4 Z9 4 U1 1 U2 10 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 SN 1071-5827 BN 0-8031-2045-1 J9 AM SOC TEST MATER PY 1997 VL 1280 BP 184 EP 207 DI 10.1520/STP16218S PG 24 WC Mechanics; Materials Science, Characterization & Testing SC Mechanics; Materials Science GA BH07U UT WOS:A1997BH07U00009 ER PT J AU Lightstone, M Majani, E Mitra, SK AF Lightstone, M Majani, E Mitra, SK TI Low bit-rate design considerations for wavelet-based image coding SO MULTIDIMENSIONAL SYSTEMS AND SIGNAL PROCESSING LA English DT Article DE wavelets; image coding; filter design ID FILTER BANKS AB Biorthogonal and orthogonal filter pairs derived from the family of binomial product filters are considered for wavelet transform implementation with the goal of high performance lossy image compression. Using experimental rate-distortion performance as the final measure of comparison, a number of new and existing filters are presented with excellent image coding capabilities. In addition, numerous filter attributes such as orthonormality, transition band sharpness, coding gain, low-band reconstruction error, regularity, and vanishing moments are assessed to determine their importance with regards to the fidelity of the decoded images. While image data compression is specifically addressed, many of the proposed techniques are applicable to other coding applications. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF SANTA BARBARA,DEPT ELECT & COMP ENGN,CTR INFORMAT PROC RES,SANTA BARBARA,CA 93106. RP Lightstone, M (reprint author), CHROMAT RES CORP,615 TASIMAN DR,SUNNYVALE,CA 94089, USA. NR 30 TC 15 Z9 16 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-6082 J9 MULTIDIM SYST SIGN P JI Multidimens. Syst. Signal Process. PD JAN PY 1997 VL 8 IS 1-2 BP 111 EP 128 DI 10.1023/A:1008221023577 PG 18 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA WJ649 UT WOS:A1997WJ64900007 ER PT B AU Alexandrov, NM AF Alexandrov, NM BE Alexandrov, NM Hussaini, MY TI Multilevel methods for MDO SO MULTIDISCIPLINARY DESIGN OPTIMIZATION: STATE OF THE ART SE SIAM PROCEEDINGS SERIES LA English DT Proceedings Paper CT ICASE/NASA Langley Workshop on Multidisciplinary Design Optimization CY MAR 13-16, 1995 CL HAMPTON, VA SP Inst Comp Appl Sci & Engn, NASA Langley Res Ctr, Multidisciplinary Optimizat Branch AB From mathematical point of view, Multidisciplinary Design Optimization (MDO) problems in engineering design and other areas are extremely large and complex nonlinear programming problems with blocks of equality constraints formed by the equations that govern various contributing disciplines. Even when only parts of the problem are considered, the MDO environment gives rise to large nonlinear optimization problems with constraints occurring in blocks. We discuss the use of globally convergent out-of-core multilevel optimization methods in application to MDO problems. The class of multilevel algorithms for constrained optimization allow the user to partition constraints into arbitrary blocks which are processed separately by solving progressively smaller dimensional subproblems. The analytical conditions on these algorithms are mild. RP Alexandrov, NM (reprint author), NASA,LANGLEY RES CTR,MULTIDISCIPLINARY OPTIMIZAT BRANCH,MAIL STOP 159,HAMPTON,VA 23681, USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SIAM PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 BN 0-89871-359-5 J9 SIAM PROC S PY 1997 BP 79 EP 89 PG 11 WC Engineering, Industrial; Operations Research & Management Science; Mathematics, Applied SC Engineering; Operations Research & Management Science; Mathematics GA BH44D UT WOS:A1997BH44D00004 ER PT B AU Braun, RD Kroo, IM AF Braun, RD Kroo, IM BE Alexandrov, NM Hussaini, MY TI Development and application of the collaborative optimization architecture in a multidisciplinary design environment SO MULTIDISCIPLINARY DESIGN OPTIMIZATION: STATE OF THE ART SE SIAM PROCEEDINGS SERIES LA English DT Proceedings Paper CT ICASE/NASA Langley Workshop on Multidisciplinary Design Optimization CY MAR 13-16, 1995 CL HAMPTON, VA SP Inst Comp Appl Sci & Engn, NASA Langley Res Ctr, Multidisciplinary Optimizat Branch AB Collaborative optimization is a design architecture applicable in any multidisciplinary analysis environment but specifically intended for large-scale distributed analysis applications. In this approach, a complex problem is hierarchically decomposed along disciplinary boundaries into a number of subproblems which rare brought into multidisciplinary agreement by a system-level coordination process. When applied to problems in a multidisciplinary design environment, this scheme has several advantages over traditional solution strategies. These advantageous features include reducing the amount of information transferred between disciplines, the removal of large iteration-loops, allowing the use of different subspace optimizers among the various analysis groups, an analysis framework which is easily parallelized and can operate on heterogenous equipment, and a structural framework that is well-suited for conventional disciplinary organizations. In this article, the collaborative architecture is developed and its mathematical foundation is presented. An example application is also presented which highlights the potential of this method for use in large-scale design applications. RP Braun, RD (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 35 Z9 36 U1 1 U2 2 PU SIAM PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 BN 0-89871-359-5 J9 SIAM PROC S PY 1997 BP 98 EP 116 PG 19 WC Engineering, Industrial; Operations Research & Management Science; Mathematics, Applied SC Engineering; Operations Research & Management Science; Mathematics GA BH44D UT WOS:A1997BH44D00006 ER PT B AU Lewis, RM AF Lewis, RM BE Alexandrov, NM Hussaini, MY TI Practical aspects of variable reduction formulations and reduced basis algorithms in multidisciplinary design optimization SO MULTIDISCIPLINARY DESIGN OPTIMIZATION: STATE OF THE ART SE SIAM PROCEEDINGS SERIES LA English DT Proceedings Paper CT ICASE/NASA Langley Workshop on Multidisciplinary Design Optimization CY MAR 13-16, 1995 CL HAMPTON, VA SP Inst Comp Appl Sci & Engn, NASA Langley Res Ctr, Multidisciplinary Optimizat Branch AB This paper discusses certain connections between nonlinear programming algorithms and the formulation of optimization problems for systems governed by state constraints. I work through the calculation of the sensitivities associated with the different formulations and present some useful relationships between them. These relationships have practical consequences; if one uses a reduced basis nonlinear programming algorithm, then the implementations for the different formulations need only differ in a single step. RP Lewis, RM (reprint author), NASA,LANGLEY RES CTR,ICASE,MAIL STOP 132C,HAMPTON,VA 23681, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SIAM PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 BN 0-89871-359-5 J9 SIAM PROC S PY 1997 BP 172 EP 188 PG 17 WC Engineering, Industrial; Operations Research & Management Science; Mathematics, Applied SC Engineering; Operations Research & Management Science; Mathematics GA BH44D UT WOS:A1997BH44D00010 ER PT B AU Newman, PA Hou, GJW Taylor, AC AF Newman, PA Hou, GJW Taylor, AC BE Alexandrov, NM Hussaini, MY TI Observations regarding use of advanced CFD analysis, sensitivity analysis, and design codes in MDO SO MULTIDISCIPLINARY DESIGN OPTIMIZATION: STATE OF THE ART SE SIAM PROCEEDINGS SERIES LA English DT Proceedings Paper CT ICASE/NASA Langley Workshop on Multidisciplinary Design Optimization CY MAR 13-16, 1995 CL HAMPTON, VA SP Inst Comp Appl Sci & Engn, NASA Langley Res Ctr, Multidisciplinary Optimizat Branch AB Observations regarding the use of advanced computational fluid dynamics (CFD) analysis, sensitivity analysis (SA), and design codes in gradient-based multidisciplinary design optimization (MDO) reflect our perception of the interactions required of CFD and our experience in recent aerodynamic design optimization studies using CFD. Sample results from these latter studies are summarized for conventional optimization (analysis-SA codes) and simultaneous analysis and design optimization (design code) using both Euler and Navier-Stokes flow approximations. The amount of computational resources required for aerodynamic design using CFD via analysis-SA codes is greater than that required for design codes. Thus, an MDO formulation that utilizes the more efficient design codes where possible is desired. However, in the aerovehicle MDO problem, the various disciplines that are involved have different design points in the flight envelope; therefore, CFD analysis-SA codes are required at the aerodynamic ''off design'' points. The suggested MDO formulation is a hybrid multilevel optimization procedure that consists of both multipoint CFD analysis-SA codes and multipoint CFD design codes that perform suboptimizations. RP Newman, PA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU SIAM PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 BN 0-89871-359-5 J9 SIAM PROC S PY 1997 BP 263 EP 279 PG 17 WC Engineering, Industrial; Operations Research & Management Science; Mathematics, Applied SC Engineering; Operations Research & Management Science; Mathematics GA BH44D UT WOS:A1997BH44D00015 ER PT B AU Koch, MR Sandford, SP Zawodny, JM AF Koch, MR Sandford, SP Zawodny, JM BE Lurie, JB Delaney, T TI Next generation remote sensing: gas and aerosol monitoring sensorcraft (GAMS) SO MULTISPECTRAL IMAGING FOR TERRESTRIAL APPLICATIONS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Multispectral Imaging for Terrestrial Applications II CY JUL 30-31, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE remote sensing; solar occultation; spacecraft; grating spectrometer; charge-coupled device (CCD); piezoelectric; digital signal processing (DSP); advanced materials; multi-functional structures AB NASA Langley Research Center (LaRC) is sponsoring the development of a revolutionary new concept for remote sensing from space. This concept is based on new technology and differs radically from previous paradigms, which call for building instruments that bolt to spacecraft. Langley's concept is called a ''sensorcraft''. The term sensorcraft simply designates a spaceflight remote sensing system that does not distinguish between the instrument, which performs a remote measurement, and the spacecraft bus, which provides the operational resources needed by the instrument in orbit. It integrates the resource requirements of both to minimize size, power consumption and cost. The Gas and Aerosol Monitoring Sensorcraft (GAMS) is a technology development project that seeks to revolutionize the remote sensing technique of solar occultation. An inherent limitation of solar occultation is the spatial and temporal coverage from a single spacecraft. For any given orbit there are at most two opportunities to take data, one at sunrise and one at sunset. A single satellite takes months to obtain a sufficient number of events to achieve global coverage. One solution to quicker global coverage is to launch several copies of the satellite. Unfortunately, by today's standards, this is very costly in hardware, launch costs, and in mission operations. This paper describes the effort to produce a snail, inexpensive satellite that requires minimal ground support effort. Such a satellite would be cost effective to mass-produce, be a good ''payload of opportunity'', and allow for a constellation approach yielding global coverage in a matter of days. The GAMS project will produce an autonomous sensorcraft with mass of 60 kg, requiring < 50 W average power and costing < $2M. GAMS will also perform extensive an board processing which not only helps do reduce size and weight, but will minimize mission operations requirements. A validation flight is targeted far Shuttle deployment in late 1999. This paper discusses the mission concept and the key technologies GAMS will employ to achieve a tenfold decrease in science mission costs. RP Koch, MR (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2541-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3119 BP 80 EP 89 DI 10.1117/12.278940 PG 10 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ68A UT WOS:A1997BJ68A00008 ER PT J AU Diarra, C Barstow, D AF Diarra, C Barstow, D GP TERC TI Mars exploration and education program: NASA jet propulsion laboratory and TERC SO NATIONAL CONFERENCE ON STUDENT & SCIENTIST PARTNERSHIPS - CONFERENCE REPORT LA English DT Proceedings Paper CT National Conference on Student and Scientist Partnerships CY OCT 23-25, 1996 CL NATL ACAD SCI, WASHINGTON, DC SP TERC, Concord Consortium, Natl Sci Fdn HO NATL ACAD SCI C1 TERC,PARTNERSHIPS CONFERENCE,CAMBRIDGE,MA 02140. RP Diarra, C (reprint author), NASA,JET PROPULS LAB,MARS EXPLORAT EDUC & PUBL OUTREACH PROGRAM,4800 OAK GROVE BLVD,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU TERC SSP CONFERENCE PI CAMBRIDGE PA 2067 MASSACHUSETTS AVENUE, CAMBRIDGE, MA 02140 PY 1997 BP 80 EP 84 PG 3 WC Education, Scientific Disciplines SC Education & Educational Research GA BJ19R UT WOS:A1997BJ19R00016 ER PT B AU Mosier, KL AF Mosier, KL BE Zsambok, CE Klein, G TI Myths of expert decision making and automated decision aids SO NATURALISTIC DECISION MAKING SE EXPERTISE: RESEARCH AND APPLICATIONS LA English DT Proceedings Paper CT 2nd Naturalistic Decision Making Conference CY JUN, 1994 CL DAYTON, OH SP Klein Associates Inc, Armstrong Lab, Human Engn Div, USA Res Inst Behav & Social Sci, USA Res Lab, Human Res & Engn Directorate, Crew Syst Ergon Informat Anal Ctr, NASA, Ames Res Ctr, Naval Air Warfare Ctr, Training Syst Div, Naval Command, Control & Ocean Surveillance Ctr, USN, Off Naval Res C1 SAN JOSE STATE UNIV FDN,NASA,AMES RES CTR,SAN JOSE,CA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 BN 0-8058-1873-1 J9 EXP RES APPL PY 1997 BP 319 EP 330 PG 12 WC Psychology, Experimental SC Psychology GA BH21E UT WOS:A1997BH21E00030 ER PT B AU Orasanu, J Fischer, U AF Orasanu, J Fischer, U BE Zsambok, CE Klein, G TI Finding decisions in natural environments: The view from the cockpit SO NATURALISTIC DECISION MAKING SE EXPERTISE: RESEARCH AND APPLICATIONS LA English DT Proceedings Paper CT 2nd Naturalistic Decision Making Conference CY JUN, 1994 CL DAYTON, OH SP Klein Associates Inc, Armstrong Lab, Human Engn Div, USA Res Inst Behav & Social Sci, USA Res Lab, Human Res & Engn Directorate, Crew Syst Ergon Informat Anal Ctr, NASA, Ames Res Ctr, Naval Air Warfare Ctr, Training Syst Div, Naval Command, Control & Ocean Surveillance Ctr, USN, Off Naval Res C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 31 Z9 32 U1 1 U2 1 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 BN 0-8058-1873-1 J9 EXP RES APPL PY 1997 BP 343 EP 357 PG 15 WC Psychology, Experimental SC Psychology GA BH21E UT WOS:A1997BH21E00032 ER PT S AU Helin, EF Pravdo, SH Rabinowitz, DL Lawrence, KJ AF Helin, EF Pravdo, SH Rabinowitz, DL Lawrence, KJ BE Remo, JL TI Near-earth asteroid tracking (NEAT) program SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs AB The discoveries of near-Earth asteroids (NEAs) and comets have increased enormously over the last 10-20 years. This is a consequence, in large part, of the success of programs that have systematically searched for these objects. These programs have been motivated by the relationships of NEAs to terrestrial impacts, meteorites, comets, and their relative accessibility to spacecraft missions. This paper will review the long-term Palomar Planet-Crossing Asteroid Survey (PCAS), a photographic program, and the current Near-Earth Asteroid Tracking (NEAT) system, NASA's new electronic detection program. The primary goal of NEAT is to discover and inventory near-Earth asteroids and comets, collectively called near-Earth objects or NEOs, larger than 1 km in size. Details of the NEAT system and program results are presented and discussed. RP Helin, EF (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MS 183-501, PASADENA, CA 91109 USA. NR 17 TC 13 Z9 13 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 6 EP 25 DI 10.1111/j.1749-6632.1997.tb48329.x PG 20 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00002 ER PT S AU Yeomans, DK AF Yeomans, DK BE Remo, JL TI The uncertain nature of cometary motions SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs RP Yeomans, DK (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 26 EP 26 DI 10.1111/j.1749-6632.1997.tb48330.x PG 1 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00003 ER PT S AU Weissman, PR AF Weissman, PR BE Remo, JL TI Long-period comets and the oort cloud SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs ID MASS EXTINCTIONS; SOLAR-SYSTEM; GALACTIC PLANE; IMPACT PROBABILITIES; ORIGINAL ORBITS; SHOWERS; COLLISIONS; EVOLUTION; MOTION; EARTH AB The long-period comets pose a unique problem for the impact hazard problem. Because of their very long orbital periods and generally large distances from the Sun, they cannot be surveyed and catalogued in the same manner as the near-Earth asteroids and short-period comets. They appear at random, uniformly distributed on the celestial sphere. Current technologies can detect long-period comets at distances of similar to 5 AU, giving somewhat less than a one year warning time for potential Earth impactors. The mean impact probability for a long-period comet crossing the Earth's orbit is 2.2 to 2.5 x 10(-9) per perihelion passage. The mean impact velocity is similar to 52 km sec(-1), but the most probable impact energy is characterized by a velocity of 56 to 58 km sec(-1). The estimated current impact rate for cometary nuclei large enough to create 10 km diameter (or larger) craters on the Earth is between 5 x 10(-7) and 2.8 x 10(-6) per year, with a best estimated value of 1.0 x 10(-6) per year. Nuclei large enough to initiate global climatic disturbances strike the Earth, on average, every 16 Myr. The impact frequency may be increased substantially for brief periods of time during cometary showers, initiated by major perturbations of the Oort cloud. Improved technologies are needed to detect approaching long-period comets at large heliocentric distances so as to increase the warning time for potential impactors. RP Weissman, PR (reprint author), CALTECH, JET PROP LAB, DIV EARTH & SPACE SCI, MS 183-601, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 91 TC 12 Z9 12 U1 0 U2 3 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 67 EP 95 DI 10.1111/j.1749-6632.1997.tb48335.x PG 29 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00008 ER PT S AU Ostro, SJ AF Ostro, SJ BE Remo, JL TI Radar reconnaissance of near-earth objects at the dawn of the next millennium SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs ID ASTEROID-4179 TOUTATIS; IMAGES; ASTROMETRY; ASTRONOMY; SHAPE AB Radar, the most powerful ground-based technique for postdiscovery investigation of NEOs (near-Earth objects), can contribute a great deal to their exploration as well as to identification and mitigation of hazardous objects. My intentions in this article are to review the current state of NEO radar reconnaissance, examine the imminent prospects for this work as upgraded instrumentation becomes available, and propose construction of a next-generation radar telescope that, unlike any existing radar instrument, would be optimized for, and dedicated to, NEO radar. RP Ostro, SJ (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 36 TC 3 Z9 3 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 118 EP 139 DI 10.1111/j.1749-6632.1997.tb48337.x PG 22 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00010 ER PT S AU Toon, OB Zahnle, K Morrison, D Turco, RP Covey, C AF Toon, OB Zahnle, K Morrison, D Turco, RP Covey, C BE Remo, JL TI Environmental perturbations caused by the impacts of asteroids and comets SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs C1 UNIV CALIF LOS ANGELES, LOS ANGELES, CA 90095 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RP Toon, OB (reprint author), NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 0 TC 2 Z9 2 U1 0 U2 2 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 401 EP 402 DI 10.1111/j.1749-6632.1997.tb48357.x PG 2 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00030 ER PT S AU Rampino, MR Haggerty, BM Pagano, TC AF Rampino, MR Haggerty, BM Pagano, TC BE Remo, JL TI A unified theory of impact crises and mass extinctions: Quantitative tests SO NEAR-EARTH OBJECTS: UNITED NATIONS INTERNATIONAL CONFERENCE SE Annals of the New York Academy of Sciences LA English DT Review CT International Conference on Near-Earth Objects CY APR 24-26, 1995 CL NEW YORK, NY SP Amer Museum Nat Hist, Explorers Club, NASA, Planetary Soc, Quantametrics Inc, Sandia Natl Labs, UN Off Outer Space Affairs ID CRETACEOUS-TERTIARY BOUNDARY; PERMIAN TRIASSIC BOUNDARY; PERIODIC COMET SHOWERS; ASTEROID IMPACT; MEDICINE FORMATION; METEORITE IMPACT; SOLAR COMPANION; CARBON-ISOTOPE; SHOCKED QUARTZ; FOSSIL RECORD AB Several quantitative tests of a general hypothesis linking impacts of large asteroids and comets with mass extinctions of life are possible based on astronomical data, impact dynamics, and geological information. The waiting times of large-body impacts on the Earth derived from the flux of Earth-crossing asteroids and comets, and the estimated size of impacts capable of causing large-scale environmental disasters, predict that impacts of objects greater than or equal to 5 km in diameter (greater than or equal to 10(7) Mt TNT equivalent) could be sufficient to explain the record of similar to 25 extinction pulses in the last 540 Myr, with the 5 recorded major mass extinctions related to impacts of the largest objects of greater than or equal to 10 km in diameter (greater than or equal to 10(8) Mt events). Smaller impacts (similar to 10(6) Mt), with significant regional environmental effects, could be responsible for the lesser boundaries in the geologic record. Tests of the ''kill curve'' relationship for impact-induced extinctions based on new data on extinction intensities, and several well-dated large impact craters, also suggest that major mass extinctions require large impacts, and that a step in the kill curve may exist at impacts that produce craters of similar to 100 km diameter, smaller impacts being capable of only relatively weak extinction pulses. Single impact craters less than similar to 60 km in diameter should not be associated with detectable global extinction pulses (although they may explain stage and zone boundaries marked by lesser faunal turnover), but multiple impacts in that size range may produce significant stepped extinction pulses. Statistical tests of the last occurrences of species at mass-extinction boundaries are generally consistent with predictions for abrupt or stepped extinctions, and several boundaries are known to show ''catastrophic'' signatures of environmental disasters and biomass crash, impoverished postextinction fauna and flora dominated by stress-tolerant and opportunistic species, and gradual ecological recovery and radiation of new taxa. Isotopic and other geochemical signatures are also generally consistent with the expected after-effects of catastrophic impacts. Seven of the recognized extinction pulses seem to be associated with concurrent (in some cases multiple) stratigraphic impact markers (e.g., layers with high iridium, shocked minerals, microtektites), and/or large, dated impact craters. Other less well-studied crisis intervals show elevated iridium, but well below that of the K/T spike, which might be explained by low-Ir impactors, ejecta blowoff, or sedimentary reworking and dilution of impact signatures. The best explanation for a possible periodic component of similar to 30 Myr in mass extinctions and clusters of impacts is the pulselike modulation of the comet flux associated with the solar system's periodic passage through the plane of the Milky Way Galaxy. The quantitative agreement between paleontologic and astronomical data suggests an important underlying unification of the processes involved. C1 NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NYU, DEPT PHYS, NEW YORK, NY 10003 USA. RP Rampino, MR (reprint author), NYU, EARTH & ENVIRONM SCI PROGRAM, 26 STUYVESANT ST, NEW YORK, NY 10003 USA. RI Pagano, Thomas/C-4659-2011 NR 149 TC 18 Z9 18 U1 2 U2 11 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-040-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1997 VL 822 BP 403 EP 431 DI 10.1111/j.1749-6632.1997.tb48358.x PG 29 WC Astronomy & Astrophysics; Multidisciplinary Sciences SC Astronomy & Astrophysics; Science & Technology - Other Topics GA BJ16N UT WOS:A1997BJ16N00031 PM 11543121 ER PT J AU Pravdo, SH Angelini, L Drake, SA Stern, RA White, NE AF Pravdo, SH Angelini, L Drake, SA Stern, RA White, NE TI The X-ray evidence that the 51 Peg companion is a planet SO NEW ASTRONOMY LA English DT Article DE binaries: close; binaries: spectroscopic; stars: evolution; planetary systems; X-rays: stars ID SOLAR-TYPE STARS; BINARY STARS; EVOLUTION; EMISSION AB 51 Pegasi is a nearby G2-3 V star which is similar to the Sun. Mayor & Queloz (1995) [Natur, 378, 355] have recently found that 51 Peg has sinusoidal radial velocity variations with a period of 4.2 days and amplitude of 59 m/s. The radial velocity, if due to orbital motion around the system center-of-mass, implies a minimum companion mass of 0.47 Jupiter masses, which results from the assumption that the inclination angle of the system is 90 degrees from the line of sight. However, because the inclination angle is not directly measured there remains an uncertainty in the companion mass. In the limit of a near-zero inclination angle the companion could even be a late-type dwarf star. We argue that the low measured X-ray luminosity of the 51 Peg system supports the conclusion that the companion is a planet, independent of any assumption about the inclination angle. If 51 Peg were a binary stellar system with a 4-day orbital period its X-ray emission would be in marked contrast with ALL known binary stellar systems with similar orbital periods. When compared to the distribution of binary star X-ray luminosities, a system with the 51 Peg X-ray luminosity have an occurrence probability of only 1.7 x 10(-6) The low X-ray luminosity also confirms that 51 Peg is a slow rotator based upon the correlation between X-ray emission and rotational velocity. We discuss the lack of synchronization between the 51 Peg orbital and rotational periods and calculate model-dependent upper limits on the companion mass which also indicate that it is a planet. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. LOCKHEED MARTIN,SOLAR & ASTROPHYS LAB,PALO ALTO,CA 94304. RP Pravdo, SH (reprint author), CALTECH,JET PROP LAB,MAIL STOP 306-438,PASADENA,CA 91109, USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 31 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PY 1997 VL 1 IS 2 BP 171 EP 176 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WT971 UT WOS:A1997WT97100005 ER PT J AU Borgani, S Moscardini, L Plionis, M Gorski, KM Holtzman, J Klypin, A Primack, JR Smith, CC Stompor, R AF Borgani, S Moscardini, L Plionis, M Gorski, KM Holtzman, J Klypin, A Primack, JR Smith, CC Stompor, R TI Constraining the power spectrum using clusters SO NEW ASTRONOMY LA English DT Review DE galaxies: clusters; dark matter; large-scale structure of universe ID LARGE-SCALE STRUCTURE; COLD DARK-MATTER; X-RAY-CLUSTERS; RICH CLUSTERS; GALAXY CLUSTERS; REDSHIFT SURVEY; GRAVITATIONAL-INSTABILITY; ZELDOVICH APPROXIMATION; HUBBLE CONSTANT; UNIVERSE AB We analyze an extended redshift sample of Abell/ACO clusters and compare the results with those coming from numerical simulations of the cluster distribution, based on the truncated Zel'dovich approximation (TZA), for a list of eleven dark matter (DM) models. For each model we run several realizations, so that we generate a set of 48 independent mock Abell/ACO cluster samples per model, on which we estimate cosmic variance effects. Other than the standard CDM model, we consider (a) Ohm(0) = 1 CDM models based on lowering the Hubble parameter and/or on tilting the primordial spectrum; (b) Ohm(0) = 1 Cold + Hot DM models with 0.1 less than or equal to Ohm(nu) less than or equal to 0.5; (c) low-density flat Lambda CDM models with 0.3 less than or equal to Ohm(0) less than or equal to 0.5. We compare real and simulated cluster distributions by analysing correlation statistics, the probability density function, and supercluster properties from percolation analysis. We introduce a generalized definition of the spectrum shape parameter Gamma in terms of sigma(25)/sigma(g), where sigma(r) is the rms fluctuation amplitude within a sphere of radius r. As a general result, we find that the distribution of galaxy clusters provides a constraint only on the shape of the power spectrum, but not on its amplitude: a shape parameter 0.18 less than or similar to Gamma less than or similar to 0.25 and an effective spectral index at the 20 h(-1) Mpc scale -1.1 less than or similar to n(eff) less than or similar to -0.9 are required by the Abell/ACO data. In order to obtain complementary constraints on the spectrum amplitude, we consider the cluster abundance as estimated using the Press-Schechter approach, whose reliability is explicitly tested against N-body simulations. By combining results from the analysis of the distribution and the abundance of clusters we conclude that, of the cosmological models considered here, the only viable models are either Cold + Hot DM ones with 0.2 less than or similar to Q(nu) less than or similar to 0.3, better if shared between two massive nu species, and Lambda CDM ones with 0.3 less than or similar to Ohm(0) less than or similar to 0.5. C1 SCH ADV INT STUDIES, SISSA, I-34013 TRIESTE, ITALY. UNIV PADUA, DIPARTIMENTO ASTRON, I-35122 PADUA, ITALY. NATL OBSERV ATHENS, ATHENS 18110, GREECE. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, HUGHES STX CORP, GREENBELT, MD 20771 USA. NEW MEXICO STATE UNIV, DEPT ASTRON, LAS CRUCES, NM 88003 USA. UNIV CALIF SANTA CRUZ, DEPT PHYS, SANTA CRUZ, CA 95064 USA. UNIV OXFORD, DEPT PHYS, OXFORD OX1 3RH, ENGLAND. COPERNICUS ASTRON CTR, PL-00716 WARSAW, POLAND. RP Borgani, S (reprint author), UNIV PERUGIA, DIPARTIMENTO FIS, IST NAZL FIS NUCL, VIA A PASCOLI, I-06100 PERUGIA, ITALY. RI Plionis, Manolis/K-4354-2013; OI Borgani, Stefano/0000-0001-6151-6439 NR 127 TC 34 Z9 34 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1384-1092 J9 NEW ASTRON JI New Astron. PY 1997 VL 1 IS 4 BP 321 EP 347 DI 10.1016/S1384-1076(96)00021-8 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WT973 UT WOS:A1997WT97300003 ER PT B AU Dobinson, E Raskin, R AF Dobinson, E Raskin, R GP IEEE COMP SOC TI Remote access tool for Earth science data SO NINTH INTERNATIONAL CONFERENCE ON SCIENTIFIC AND STATISTICAL DATABASE MANAGEMENT, PROCEEDINGS LA English DT Proceedings Paper CT 9th International Conference on Scientific and Statistical Database Management (9SSDBM) CY AUG 11-13, 1997 CL EVERGREEN STATE COLL, OLYMPIA, WA HO EVERGREEN STATE COLL AB This demo presents an http-based client/server application prototype that facilitates internet access to Earth science data. The client consists of a Java applet GUI that allows the user to select spatial/temporal subsets of indexed datasets. The client also includes a MATLAB interface that allows the incoming data to be loaded directly into a MATLAB session. The server provides directory, catalog, and data access services and performs the subsetting operations prior to data transmission. An example is presented where data from multiple sources and in multiple formats are combined into a single MATLAB plot. The prototype addresses the lack of common data models in the Earth sciences. It also addresses the need for access to corroborating data by Earth Observation Satellite (EOS) instrument team members for calibration and validation. RP Dobinson, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7953-0 PY 1997 BP 119 EP 120 DI 10.1109/SSDM.1997.621170 PG 2 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Computer Science GA BJ47Y UT WOS:A1997BJ47Y00016 ER PT J AU Lo, MW AF Lo, MW TI Libration point trajectory design SO NUMERICAL ALGORITHMS LA English DT Article; Proceedings Paper CT Conference on Dynamical Numerical Analysis CY DEC 14-16, 1995 CL GEORGIA INST TECHNOL, SCH MATH, ATLANTA, GA SP Natl Sci Fdn, Div Math, Computat Math Program HO GEORGIA INST TECHNOL, SCH MATH AB Orbits about the Sun-Earth L-1 and L-2 libration points have become very popular for space physics and astrophysics missions, Due to the hyperbolicity of the region of phase space where these orbits are found, they are difficult to compute and analyze. The invariant manifold structure provided by dynamical systems theory has been useful to compute transfer trajectories between or bits. These methods are very promising and require further development. This systematic approach is a great improvement from the difficult and labor-intensive numerical search methods currently popular in the astrodynamics community for studying these orbits. The geometric constraints and mission critical issues are discussed to give the numerical dynamical systems community some insight into the practical considerations and important problems of interest to the space mission designers. It is hoped that this communication will lead to more fruitful exchanges between the two communities. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. PURDUE UNIV, W LAFAYETTE, IN 47907 USA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU BALTZER SCI PUBL BV PI AMSTERDAM PA ASTERWEG 1A, 1031 HL AMSTERDAM, NETHERLANDS SN 1017-1398 J9 NUMER ALGORITHMS JI Numer. Algorithms PY 1997 VL 14 IS 1-3 BP 153 EP 164 DI 10.1023/A:1019108929089 PG 12 WC Mathematics, Applied SC Mathematics GA XE683 UT WOS:A1997XE68300009 ER PT J AU Gehrels, N AF Gehrels, N TI Use of vF(v) spectral energy distributions for multiwavelength astronomy SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA B-GENERAL PHYSICS RELATIVITY ASTRONOMY AND MATHEMATICAL PHYSICS AND METHODS LA English DT Article ID ACTIVE GALACTIC NUCLEI; RV TAURI STARS; RAY; EMISSION AB Spectral Energy Distribution (SED) plots of log(vF(v)) vs. log(v) have become popular for multiwavelength astronomy because they give the source power per logarithmic frequency interval and thereby directly show the relative energy output in each frequency band. They also allow easy manipulation and integration of black-body spectra. However, usage can be tricky and misuse is common. This paper derives equations for manipulating SEDs. RP Gehrels, N (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Gehrels, Neil/D-2971-2012 NR 26 TC 11 Z9 11 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 0369-3554 J9 NUOVO CIMENTO B JI Nouvo Cimento Soc. Ital. Fis. B-Gen. Phys. Relativ. Astron. Math. Phys. Methods PD JAN PY 1997 VL 112 IS 1 BP 11 EP 15 PG 5 WC Physics, Multidisciplinary SC Physics GA WR743 UT WOS:A1997WR74300003 ER PT B AU Gary, C Timucin, D AF Gary, C Timucin, D GP IEEE TI Holographic data storage using bacteriorhodopsin SO ODS - 1997 OPTICAL DATA STORAGE TOPICAL MEETING, CONFERENCE DIGEST LA English DT Proceedings Paper CT 1997 Optical Data Storage Topical Meeting CY APR 07-09, 1997 CL TUCSON, AZ SP IEEE, Lasers & Electro Opt Soc, Opt Soc Amer, Soc Photo Opt Instrumentat Engineers RP Gary, C (reprint author), NASA,AMES RES CTR,MAIL STOP 269-3,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3885-5 PY 1997 BP 62 EP 63 DI 10.1109/ODS.1997.606117 PG 2 WC Optics SC Optics GA BJ19V UT WOS:A1997BJ19V00029 ER PT J AU Bullock, SR Reddy, BR Venkateswarlu, P NashStevenson, SK Fajardo, JC AF Bullock, SR Reddy, BR Venkateswarlu, P NashStevenson, SK Fajardo, JC TI Energy upconversion and spectroscopic studies of ZBLAN:Er3+ SO OPTICAL AND QUANTUM ELECTRONICS LA English DT Article ID UP-CONVERSION; FLUORIDE GLASS; FIBER LASER; GREEN; IONS AB A detailed spectroscopic investigation of ZBLAN:Er3+ sample was performed. Infrared to green, red to blue and blue to ultraviolet energy upconversion studies in this material were also performed. When the material was pumped with a 637 nm dye laser upconversion signals at 402 nm, whose efficiency is similar to 0.04%, were detected. Intensity parameters, transition probabilities, lifetimes and quantum efficiencies are also obtained. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RUTGERS STATE UNIV,FIBER OPT MAT RES PROGRAM,PISCATAWAY,NJ 08855. RP Bullock, SR (reprint author), ALABAMA A&M UNIV,DEPT PHYS,POB 1268,NORMAL,AL 35762, USA. NR 16 TC 12 Z9 12 U1 1 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0306-8919 J9 OPT QUANT ELECTRON JI Opt. Quantum Electron. PD JAN PY 1997 VL 29 IS 1 BP 83 EP 92 DI 10.1023/A:1018533501251 PG 10 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA WK198 UT WOS:A1997WK19800009 ER PT B AU Gary, C AF Gary, C BE Birecki, H Kwiecien, JZ TI Holographic data storage using bacteriorhodopsin SO OPTICAL DATA STORAGE '97 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1997 Optical Data Storage Topical Meeting CY APR 07-09, 1997 CL TUCSON, AZ SP IEEE, Lasers & Electro Opt Soc, Opt Soc Amer, Soc Photo Opt Instrumentat Engineers DE bacteriorhodopsin; optical memory; holography; data storage; optical data storage; holographic data storage AB Our measurements show that the diffraction efficiency falls off as the square of the number of holograms, and the recording order does not appear to be significant for holographic data storage in baeteriorhodopsin. RP Gary, C (reprint author), NASA,AMES RES CTR,MAIL STOP 269-3,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2530-3 J9 P SOC PHOTO-OPT INS PY 1997 VL 3109 BP 188 EP 191 DI 10.1117/12.280669 PG 4 WC Computer Science, Information Systems; Optics SC Computer Science; Optics GA BJ50X UT WOS:A1997BJ50X00025 ER PT J AU KeskiKuha, RAM Osantowski, JF Leviton, DA Saha, TT Wright, GA Boucarut, RA Fleetwood, CM Madison, TJ AF KeskiKuha, RAM Osantowski, JF Leviton, DA Saha, TT Wright, GA Boucarut, RA Fleetwood, CM Madison, TJ TI Chemical vapor deposited silicon carbide mirrors for extreme ultraviolet applications SO OPTICAL ENGINEERING LA English DT Article DE silicon carbide; CVD-SiC; extreme ultraviolet; FUV; optical materials AB Advances in optical coating and materials technology have made possible the development of instruments with substantially improved efficiency in the extreme ultraviolet (EUV). For example, the development of chemical vapor deposited (CVD) SIC mirrors provides an opportunity to extend the range of normal-incidence instruments down to 60 nm. CVD SIC is a highly polishable material yielding low-scattering surfaces. High UV reflectivity and desirable mechanical and thermal properties make CVD SIC an attractive mirror and/or coating material for EUV applications. The EUV performance of SiC mirrors, as well as some strengths and problem areas, is discussed. (C) 1997 Society of Photo-Optical Instrumentation Engineers. RP KeskiKuha, RAM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 18 TC 12 Z9 14 U1 0 U2 2 PU SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1997 VL 36 IS 1 BP 157 EP 161 DI 10.1117/1.601128 PG 5 WC Optics SC Optics GA WD106 UT WOS:A1997WD10600021 ER PT B AU Chao, TH Park, Y Reyes, G AF Chao, TH Park, Y Reyes, G BE Casasent, DP Chao, TH TI High-speed camera-sized optical wavelet processor SO OPTICAL PATTERN RECOGNITION VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition VIII CY APR 22-23, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE high speed Optical correlation; optical wavelet transforms; optical morphology; optical correlator; bipolar-amplitude modulation SLM; noise and clutter suppression AB A compact (Camcorder size), ultrahigh-speed, optical correlator using bipolar-amplitude-valued filtering is described. The system compactness and high speed is achieved by utilizing a newly developed nematic twist liquid crystal SLM by KOPIN (Model #LVGA640x480, with 640 x 480 pixels,,60 frames/sec) as the input SLM and a ferroelectric liquid crystal SLM (Model #Analog128x128, 128 x 128 pixel, 40-mu pitch, 1000 frames/sec), optics design, and miniature packaging components. The utilization of a ferroelectric spatial light modulator (SLM) developed by Boulder Nonlinear System (BNS) in the Fourier transform domain of the optical correlator has enabled the bipolar-amplitude modulation for filter synthesis. The unique bipolar-amplitude modulation characteristics of the BNS SLM has made possible the designed of real-valued spatial filters for pattern recognition. We have demonstrated the superiority of this real-valued filter for higher signal-to-noise-ratio (SNR) correlation under cluttered environment. Moreover, the real-valued filter synthesis capability also allow us to extend the processing capability from mere optical correlation to optical wavelet transform, optical morphological processing and many other processing operations. RP Chao, TH (reprint author), CALTECH,JET PROP LAB,MS 303-300,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2488-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3073 BP 194 EP 200 DI 10.1117/12.270365 PG 3 WC Optics SC Optics GA BH52H UT WOS:A1997BH52H00020 ER EF