FN Thomson Reuters Web of Science™ VR 1.0 PT J AU RITTER, RD AF RITTER, RD TI PILOT ERROR IN AUTOMATED SYSTEMS SHOWN BY ALTITUDE DEVIATION REPORTS SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB Over 8,000 altitude deviations are reported to NASA's Aviation Safety Reporting System each year. This is almost one an hour. The narratives of pilot incidents relate how errors made in the automation-assisted altitude change task are caused by the difficulty pilots are having interacting with automatic systems. This paper discusses the impact of increased automation in glass-cockpit airliners on the altitude deviations reported by pilots. By observing the way information is processed by the cockpit system, the author suggests that the philosophies of design and training need change in order to facilitate, not debilitate, the aircrew. RP RITTER, RD (reprint author), NASA,AMES RES CTR,FAA,TECH FIELD OFF,MS 210-2,MOFFETT FIELD,CA 94035, USA. NR 7 TC 1 Z9 1 U1 2 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD APR PY 1994 VL 9 IS 4 BP 15 EP 19 DI 10.1109/62.277748 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA NE469 UT WOS:A1994NE46900003 ER PT J AU DAVARIAN, F AF DAVARIAN, F TI EARTH-SATELLITE PROPAGATION RESEARCH SO IEEE COMMUNICATIONS MAGAZINE LA English DT Article ID L-BAND; ATTENUATION C1 LOYOLA MARYMOUNT UNIV,DEPT ENGN,LOS ANGELES,CA 90045. JET PROP LAB,NASA,RADIO WAVE PROPAGAT PROGRAM,PASADENA,CA 91109. RP DAVARIAN, F (reprint author), JET PROP LAB,SPECTRUM ENGN GRP,PASADENA,CA 91109, USA. NR 36 TC 6 Z9 6 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 0163-6804 J9 IEEE COMMUN MAG JI IEEE Commun. Mag. PD APR PY 1994 VL 32 IS 4 BP 74 EP 79 DI 10.1109/35.275338 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA NG118 UT WOS:A1994NG11800008 ER PT J AU ERICKSON, JD AF ERICKSON, JD TI INTELLIGENT ROBOTICS IN-FIELD, FACTORY, SERVICE, AND SPACE SO IEEE EXPERT-INTELLIGENT SYSTEMS & THEIR APPLICATIONS LA English DT Editorial Material RP ERICKSON, JD (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0885-9000 J9 IEEE EXPERT JI IEEE Expert-Intell. Syst. Appl. PD APR PY 1994 VL 9 IS 2 BP 61 EP 61 PG 1 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA NW850 UT WOS:A1994NW85000008 ER PT J AU CHOUDHURY, D RAISANEN, AV SMITH, RP FRERKING, MA AF CHOUDHURY, D RAISANEN, AV SMITH, RP FRERKING, MA TI STUDY OF THE EFFECT OF THE CMAX/CMIN RATIO ON THE PERFORMANCE OF BACK-TO-BACK BARRIER-N-N (BBBNN) VARACTOR FREQUENCY-MULTIPLIERS SO IEEE MICROWAVE AND GUIDED WAVE LETTERS LA English DT Article AB The effect of the C(max)/C(min) ratio on the performance of planar back-to-back Barrier-NN-NN+ (bbBNN) frequency multipliers is studied. A simplified physical model of the device is used to relate the electrical characteristics to the material and the structural parameters. Multiplication efficiency is evaluated using a large signal analysis approach. Results indicate that if the optimum device size for a given frequency is used, a high C(max)/C(min) ratio results in high efficiency. RP CHOUDHURY, D (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. RI Raisanen, Antti/G-2405-2013 NR 0 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8207 J9 IEEE MICROW GUIDED W JI IEEE Microw. Guided Wave Lett. PD APR PY 1994 VL 4 IS 4 BP 101 EP 103 DI 10.1109/75.282572 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA NL836 UT WOS:A1994NL83600001 ER PT J AU SHIVELY, D AF SHIVELY, D TI SCATTERING FROM PERFECTLY CONDUCTING AND RESISTIVE STRIPS ON A GROUNDED DIELECTRIC SLAB SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Note ID BACKSCATTERING AB The scattering properties of perfectly conducting and resistive strips are predicted for strips which are located on a dielectric slab backed by a perfectly conducting ground plane. The spectral domain Green's function is used to relate the currents and fields on the strip, and the resulting integral equation is solved using the method of moments. Both TE and TM strips are examined using piecewise linear and pulse subdomain basis functions, respectively, to model the current on the strip. Calculated results are compared with results measured at the NASA Langley Research Center. RP SHIVELY, D (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 490,HAMPTON,VA 23681, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD APR PY 1994 VL 42 IS 4 BP 552 EP 556 DI 10.1109/8.286228 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA NQ840 UT WOS:A1994NQ84000017 ER PT J AU KORMANYOS, BK HAROKOPUS, W KATEHI, LPB REBEIZ, GM AF KORMANYOS, BK HAROKOPUS, W KATEHI, LPB REBEIZ, GM TI CPW-FED ACTIVE SLOT ANTENNAS SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article AB We have combined microwave oscillator design with theoretical characterization of planar antennas to build active slot-oscillators. The design is uniplanar, does not require via holes and is compatible with monolithic transistor technology. The coplanar waveguide (CPW) fed antenna impedance is calculated using the space domain integral equation technique (SDIE), a full wave method of moments approach. Slot-oscillators were built at 7 GHz and 20 GHz and the predicted oscillation frequencies agree well with experiments. The 20 GHz medium power oscillator has an output power of 17 mW and a DC to RF efficiency of 14%. The design is easily scaled to millimeter-wave frequencies and can be extended to power combining arrays. C1 TEXAS INSTRUMENTS INC,DEF SYST & ELECTR GRP,MCKINNEY,TX 75070. RP KORMANYOS, BK (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. NR 14 TC 85 Z9 85 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 541 EP 545 DI 10.1109/22.285057 PN 1 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA NM297 UT WOS:A1994NM29700001 ER PT J AU WENGLER, MJ REBEIZ, GM AF WENGLER, MJ REBEIZ, GM TI SPECIAL SECTION ON SPACE TERAHERTZ TECHNOLOGY SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Editorial Material C1 UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109. RP WENGLER, MJ (reprint author), UNIV ROCHESTER,DEPT ELECT ENGN,ROCHESTER,NY 14627, 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 697 EP 697 PN 2 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA NM299 UT WOS:A1994NM29900001 ER PT J AU ZMUIDZINAS, J LEDUC, HG STERN, JA CYPHER, SR AF ZMUIDZINAS, J LEDUC, HG STERN, JA CYPHER, SR TI 2-JUNCTION TUNING CIRCUITS FOR SUBMILLIMETER SIS MIXERS SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article; Proceedings Paper CT 4th International Symposium on Space Terahertz Technology CY MAR, 1993 CL UNIV CALIF LOS ANGELES, LOS ANGELES, CA SP NASA, OFF ADV CONCEPTS & TECHNOL, IEEE, MICROWAVE THEORY & TECH SOC, UNIV MICHIGAN, NASA CTR SPACE TERAHERTZ TECHNOL, UCLA CTR HIGH FREQUENCY ELECTR HO UNIV CALIF LOS ANGELES ID LOW-NOISE; MILLIMETER; RECEIVER; WAVELENGTHS; ASTRONOMY; GHZ AB The capacitance of superconducting tunnel junctions can seriously degrade the performance of quasiparticle (SIS) mixers operating in the submillimeter band, so it is essential to provide a circuit for tuning out this capacitance at the operating frequency. In this article, we present two new tuning circuits for SIS mixers which use a pair of SIS junctions connected by an inductance. Compared to previously proposed tuning circuits, ours have a broader bandwidth, are easier to scale to higher frequencies, and may be easier to fabricate. We have constructed quasi-optical mixers which employ these tuning circuits, using Nb/Al-Oxide/Nb SIS junctions defined by optical lithography. The performance of these devices is excellent, giving receiver noise temperatures of 113 K (DSB) at 490 GHz and 230 K DSB at 612 GHz. In addition to demonstrating the effectiveness of our tuning circuit, these results show that quasi-optical mixers can be competitive with or superior to waveguide mixers at submillimeter wavelengths. The mixers continue to perform well at frequencies up to 672 GHz, which is about 95% of the Nb gap frequency. C1 JET PROP LAB,TECH STAFF,PASADENA,CA 91109. RP ZMUIDZINAS, J (reprint author), CALTECH,GEORGE W DOWNSLAB PHYS,PASADENA,CA 91125, USA. NR 19 TC 83 Z9 84 U1 1 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 698 EP 706 DI 10.1109/22.285084 PN 2 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA NM299 UT WOS:A1994NM29900002 ER PT J AU LEE, TH EAST, JR CHI, CY REBEIZ, GM DENGLER, RJ MEHDI, I SIEGEL, PH HADDAD, GI AF LEE, TH EAST, JR CHI, CY REBEIZ, GM DENGLER, RJ MEHDI, I SIEGEL, PH HADDAD, GI TI THE FABRICATION AND PERFORMANCE OF PLANAR-DOPED BARRIER DIODES AS 200 GHZ SUBHARMONICALLY PUMPED MIXERS SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article; Proceedings Paper CT 4th International Symposium on Space Terahertz Technology CY MAR, 1993 CL UNIV CALIF LOS ANGELES, LOS ANGELES, CA SP NASA, OFF ADV CONCEPTS & TECHNOL, IEEE, MICROWAVE THEORY & TECH SOC, UNIV MICHIGAN, NASA CTR SPACE TERAHERTZ TECHNOL, UCLA CTR HIGH FREQUENCY ELECTR HO UNIV CALIF LOS ANGELES ID RECEIVER AB The PDB (planar doped barrier) diode consists of a p+ doping spike between two intrinsic layers and n+ ohmic contacts. Such devices can have an anti-symmetric current vs. voltage characteristic. The capacitance is approximately constant with the applied voltage, and the barrier height and device capacitance are easily adjustable. These characteristics make the PDB a candidate for millimeter- and submillimeter-wave subharmonic mixers. We have fabricated 2 and 4 mum diameter diodes with different barrier designs using GaAs epi-layers. The devices are planarized using an air-bridge and a surface channel etch. After completely removing the substrate, the devices are mounted on a quartz substrate to reduce parasitic effects. Diced diodes were tested as subharmonic mixers around 200 GHz in both a quasi-optical planar wideband subharmonic receiver and a planar-diode waveguide-mixer. The quasi-optical measurements show that a 0.23 V (and 0.4 V) barrier height GaAs diode with 2.0 muA (and 5 nA) of saturation current gives a DSB conversion loss of 10.8 dB (and 9.5 dB) and a DSB noise temperature of 3795-degrees-K (and 2450-degrees-K). The waveguide mixer measurements were made with a similar 0.23 V barrierheight PDB. Such a mixer has a minimum conversion loss of 10.2 dB and noise temperature of 3570-degrees-K, and requires only 1.2 milliwatts of available LO power. C1 JET PROP LAB,PASADENA,CA 91109. UNIV MICHIGAN,SOLID STATE ELECTR LAB,ANN ARBOR,MI 48109. RP LEE, TH (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109, USA. NR 18 TC 5 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 742 EP 749 DI 10.1109/22.285089 PN 2 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA NM299 UT WOS:A1994NM29900007 ER PT J AU CHOUDHURY, D RAISANEN, AV SMITH, RP FRERKING, MA MARTIN, SC LIU, JK AF CHOUDHURY, D RAISANEN, AV SMITH, RP FRERKING, MA MARTIN, SC LIU, JK TI EXPERIMENTAL PERFORMANCE OF A BACK-TO-BACK BARRIER-N-N+ VARACTOR TRIPLER AT 200 GHZ SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Note AB This paper describes the performance of planar back-to-back Barrier-N-N+ (bbBNN) devices for frequency multiplier applications. A tripling efficiency of 3.3% has been achieved using these devices in a 200 GHz crossed waveguide mount. This is the first experimental result with a bbBNN waveguide frequency multiplier. A technique has been developed for characterizing planar bbBNN devices with a network analyzer, which gives both the series resistance and voltage dependent capacitance of the device. The experimental results are compared with the theoretical multiplier performance, calculated using a large signal analysis approach. C1 HELSINKI UNIV TECHNOL,RADIO LAB,SF-02150 ESPOO,FINLAND. RP CHOUDHURY, D (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. RI Raisanen, Antti/G-2405-2013 NR 11 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 755 EP 758 DI 10.1109/22.285092 PN 2 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA NM299 UT WOS:A1994NM29900010 ER PT J AU LING, CC LANDRY, JC DAVEE, H CHIN, G REBEIZ, GM AF LING, CC LANDRY, JC DAVEE, H CHIN, G REBEIZ, GM TI LARGE-AREA BOLOMETERS FOR THZ POWER MEASUREMENTS SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Note AB This paper describes measurements to determine the performance and suitability of large area bolometers on thin dielectric membranes for use as wideband THz power meters. A Fourier Transform Spectrometer (FTS) was used to measure the transmission spectra of the bolometers from 0.6THz to 10THz. A linear array of bolometers was then fabricated and used to characterized the beam produces by a FIR laser at 802GHz and 2.54THz. The total power generated by the laser is determined by measuring the beam's profile and peak power density. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,GREENBELT,MD 20771. RP LING, CC (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. RI Chin, Gordon/E-1520-2012 NR 4 TC 10 Z9 10 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1994 VL 42 IS 4 BP 758 EP 760 DI 10.1109/22.285093 PN 2 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA NM299 UT WOS:A1994NM29900011 ER PT J AU BRYAN, K VOGELIUS, M AF BRYAN, K VOGELIUS, M TI A COMPUTATIONAL ALGORITHM TO DETERMINE CRACK LOCATIONS FROM ELECTROSTATIC BOUNDARY MEASUREMENTS - THE CASE OF MULTIPLE CRACKS SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article ID TOMOGRAPHY AB This paper develops an algorithm to reconstruct the locations of a collection of linear cracks inside a homogeneous electrical conductor from boundary measurements. We measure the boundary voltages induced by certain specified two-electrode current fluxes. The algorithm is based on a variation of Newton's method and it uses weighted averages of the measured boundary data. The algorithm adaptively changes the applied current fluxes at each iteration to maintain ''maximal'' sensitivity to the estimated locations of the cracks. C1 RUTGERS STATE UNIV,DEPT MATH,NEW BRUNSWICK,NJ 08903. RP BRYAN, K (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 17 TC 30 Z9 30 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD APR PY 1994 VL 32 IS 4 BP 579 EP 603 DI 10.1016/0020-7225(94)90020-5 PG 25 WC Engineering, Multidisciplinary SC Engineering GA NC065 UT WOS:A1994NC06500003 ER PT J AU WALLETT, TM QURESHI, AH AF WALLETT, TM QURESHI, AH TI CHARACTERISTICS OF A CYLINDRICAL DISK-LOADED SLOW-WAVE STRUCTURE FOUND BY THEORETICAL, EXPERIMENTAL, AND COMPUTATIONAL TECHNIQUES SO INTERNATIONAL JOURNAL OF MICROWAVE AND MILLIMETER-WAVE COMPUTER-AIDED ENGINEERING LA English DT Article AB The dispersion characteristics and interaction impedances of a disk-loaded cylindrical waveguide structure were investigated using theoretical, computer, and experimental techniques. Satisfactory agreement has been demonstrated between the experimentally determined values, the results obtained theoretically, and the computer-generated values using the ARGUS and SOS computer codes. (C) 1994 John Wiley & Sons, Inc. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP WALLETT, TM (reprint author), CLEVELAND STATE UNIV,CLEVELAND,OH 44115, USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 1050-1827 J9 INT J MICROWAVE MILL JI Int. J. Microw. Millimeter-Wave Comput.-Aided Eng. PD APR PY 1994 VL 4 IS 2 BP 125 EP 129 DI 10.1002/mmce.4570040203 PG 5 WC Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA NA411 UT WOS:A1994NA41100002 ER PT J AU ARMSTRONG, RA AF ARMSTRONG, RA TI OCEANIC FRONTS IN THE NORTHEASTERN CARIBBEAN REVEALED BY SATELLITE OCEAN COLOR IMAGING SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SALINITY; SEA RP ARMSTRONG, RA (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV,MAIL STOP 242-4,MOFFETT FIELD,CA 94035, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD APR PY 1994 VL 15 IS 6 BP 1169 EP 1171 PG 3 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA NN344 UT WOS:A1994NN34400001 ER PT J AU MORRISSEY, LA LIVINGSTON, GP DURDEN, SL AF MORRISSEY, LA LIVINGSTON, GP DURDEN, SL TI USE OF SAR IN REGIONAL METHANE EXCHANGE STUDIES SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Note ID EMISSIONS; WETLANDS; RADAR AB Significant sources of uncertainty in global trace gas budgets are due to lack of knowledge concerning the areal and temporal extent of source and sink areas. Synthetic aperture radar (SAR) is particularly suited to studies of northern ecosystems because of its all-weather operating capability which enables the acquisition of seasonal data. As key controls on methane exchange, the ability to differentiate major vegetation communities, inundation, and leaf area index (LAI) with satellite and airborne SAR data would increase the accuracy and precision of regional and seasonal estimates of methane exchange. The utility of SAR data for monitoring key controls on methane emissions from Arctic and boreal ecosystems is examined. C1 JET PROP LAB,PASADENA,CA 91109. RP MORRISSEY, LA (reprint author), NASA,AMES RES CTR,MS 242-4,MOFFETT FIELD,CA 94035, USA. NR 13 TC 19 Z9 21 U1 0 U2 5 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD APR PY 1994 VL 15 IS 6 BP 1337 EP 1342 PG 6 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA NN344 UT WOS:A1994NN34400014 ER PT J AU NOVO, EM SHIMABUKURO, YE AF NOVO, EM SHIMABUKURO, YE TI SPECTRAL MIXTURE ANALYSIS OF INLAND TROPICAL WATERS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Note ID IMAGES AB This letter presents results of experiments conducted to assess the use of linear mixing models to unmix the reflectance spectra of water. The model was tested with 11 reflectance spectra measured at Tucurui reservoir, Brazilian Amazon. The results showed that the fraction of chlorophyll reflectance accounting for the reflectance spectra of the various samples correlate significantly with the chlorophyll concentration in the 600 to 700 nm spectral region. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP NOVO, EM (reprint author), CALTECH,PASADENA,CA 91125, USA. NR 12 TC 12 Z9 12 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD APR PY 1994 VL 15 IS 6 BP 1351 EP 1356 PG 6 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA NN344 UT WOS:A1994NN34400016 ER PT J AU LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM AF LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM TI TAILORABLE DOPING-SPIKE PTSI INFRARED DETECTORS FABRICATED BY SI MOLECULAR-BEAM EPITAXY SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS LA English DT Article; Proceedings Paper CT 5th International Symposium on Silicon Molecular Beam Epitaxy (SIMBE-5), at the 1993 International Conference on Solid State Devices and Materials (SSDM 93) CY AUG 30-SEP 01, 1993 CL NIPPON CONVENT CTR, MAKUHARI MESSE, JAPAN SP JAPAN SOC APPL PHYS HO NIPPON CONVENT CTR DE INFRARED DETECTOR; PTSI; MOLECULAR BEAM EPITAXY; DOPING SPIKE; TAILORABLE CUTOFF WAVELENGTH AB By incorporating a 1-nm-thick p+ doping spike at the PtSi/Si intertace, we have successfully demonstrated extended cutoff wavelengths of PtSi Schottky infrared detectors. The extended cutoff wavelengths resulted from the reduced effective potential barriers due to the combined effects of an increased electric field near the silicide/Si intertace and the Schottky image force. The p+ doping spikes were grown by molecular beam epitaxy at 450-degrees-C using elemental boron as the dopant source, with doping concentrations ranging from 5 x 10(19) to 2 X 10(20) cm-3. The cutoff wavelengths were shown to increase with increasing doping concentrations of the p+ spikes. Thermionic emission dark current characteristics were observed and photoresponse in the LWIR regime was demonstrated. Furthermore, the effective potential barriers determined by the Richardson plots were used to study the electrically activated boron dopant concentrations of the thin (1-nm-thick) spikes. RP LIN, TL (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 13 TC 7 Z9 7 U1 0 U2 0 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 1 JI Jpn. J. Appl. Phys. Part 1 - Regul. Pap. Short Notes Rev. Pap. PD APR PY 1994 VL 33 IS 4B BP 2435 EP 2438 DI 10.1143/JJAP.33.2435 PG 4 WC Physics, Applied SC Physics GA NR959 UT WOS:A1994NR95900061 ER PT J AU LAZARUS, TL ARMAGAN, G BARNES, NP AF LAZARUS, TL ARMAGAN, G BARNES, NP TI MODELING OF RADIATIVE ENERGY-TRANSFER DYNAMICS SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 3rd International Conference: Laser M2P CY DEC 08-10, 1993 CL ECOLE NORMALE SUPER LYON, LYON, FRANCE SP FEDERAT LASER CTR, RHONE ALPES REG HO ECOLE NORMALE SUPER LYON AB A comprehensive model which can predict the Ho3+I-5(7) YAG (Y3Al5O12) manifold luminescence and radiative energy transfer rate among Ho ions for a given concentration and emission path length within the crystal has been developed. Independently, a model was devised to calculate these rates using measured lifetimes as well as calculated radiative and non-radiative lifetimes. The rates of radiative energy transfer were determined from both of these models and found to be in close agreement. C1 COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187. RP LAZARUS, TL (reprint author), NASA,LANGLEY RES CTR,MS 474,HAMPTON,VA 23681, USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD APR PY 1994 VL 4 IS C4 BP 583 EP 586 DI 10.1051/jp4:19944140 PG 4 WC Physics, Multidisciplinary SC Physics GA NT087 UT WOS:A1994NT08700131 ER PT J AU HINKLEY, JA NELSON, JB AF HINKLEY, JA NELSON, JB TI LIFETIME EXTRAPOLATION OF PMR-15 AND LARC(TM)-160 GRAPHITE COMPOSITES SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID POLYIMIDES AB Small unidirectional composite specimens of two nadimide-terminated thermosetting polyimide resins were aged in circulating air ovens at various temperatures for up to 25,000 hours. Criteria for weight loss and loss in short-beam shear strength were used to define useful lifetimes as a function of temperature. An Arrhenius relationship could be used to extrapolate the data to lower temperatures and longer times. Both LaRC(TM)-160/Celion 6000 and PMR-15/Celion 6000 graphite composites gave extrapolated use temperatures of 160-180-degrees-C for a 60,000-hour life. Apparent activation energies were 12-20 kcal/mol. RP HINKLEY, JA (reprint author), NASA,LANGLEY RES CTR,POLYMER MAT BRANCH,HAMPTON,VA 23665, USA. NR 10 TC 4 Z9 5 U1 0 U2 4 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD APR PY 1994 VL 25 IS 3 BP 45 EP 48 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA ND141 UT WOS:A1994ND14100006 ER PT J AU CHATTOPADHYAY, A NARAYAN, JR AF CHATTOPADHYAY, A NARAYAN, JR TI OPTIMIZATION PROCEDURE FOR DESIGN OF HIGH-SPEED PROP-ROTORS SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB An optimization procedure has been developed to address the complex and conflicting requirements associated with the design of high-speed proprotor aircraft. Since the key technical issues are maintenance of propulsive efficiency and aeroelastic stability in high-speed cruise without deteriorating figure of merit in hover, rotor aerodynamic performance and aeroelastic analysis are coupled, inside a closed loop, to the optimizer. The discipline couplings provide actual blade air-loads, during hover and cruise, and also provide realistic blade designs. The propulsive efficiency in high-speed cruise is used as the objective function. Constraints are also imposed on the aeroelastic stability in axial flight and the rotor figure of merit in hover. Both structural and planform design variables are used. The optimization procedure yields significant improvements in the aerodynamic characteristics of the rotor. Off-design performance studies, conducted with the optimum blade, show overall design improvements. C1 NASA,AMES RES CTR,MCAT INST,MOFFETT FIELD,CA 94035. RP CHATTOPADHYAY, A (reprint author), ARIZONA STATE UNIV,DEPT MECH & AEROSP ENGN,TEMPE,AZ 85287, USA. NR 18 TC 1 Z9 1 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 1994 VL 7 IS 2 BP 143 EP 155 DI 10.1061/(ASCE)0893-1321(1994)7:2(143) PG 13 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA QU051 UT WOS:A1994QU05100002 ER PT J AU SULLIVAN, TA KOENIG, E KNUDSEN, CW GIBSON, MA AF SULLIVAN, TA KOENIG, E KNUDSEN, CW GIBSON, MA TI PNEUMATIC CONVEYING OF MATERIALS AT PARTIAL GRAVITY SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB This project's goal was to evaluate the feasibility of pneumatic transfer for the movement of regolith (lunar soil) at a lunar base. Operation of pneumatic conveying systems at partial (lunar and Mars) gravity conditions on NASA's KC-135 aircraft allowed the determination of some key parameters necessary for the design of an operable system. Both horizontal and vertical transfer were studied. In the vertical experiment, the choking velocity for 150 mum glass spheres at lunar gravity was determined to be 1/2-1/3 the velocity required at 1 g. Pressure drops were reduced by roughly the same amount. Choking velocity and pressure-drop data for runs at Mars gravity were problematic due to the intermittent nature of the experiment. Determination of the saltation velocity in the horizontal run was also problematic, but qualitatively similar results were obtained. Comparison of the partial g results to 1 g behavior and theoretical analysis is made. C1 LUNAR & PLANETARY INST,HOUSTON,TX 77059. CARBOTEK INC,HOUSTON,TX 77084. RP SULLIVAN, TA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL STOP SN4,HOUSTON,TX 77058, USA. NR 11 TC 3 Z9 3 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 1994 VL 7 IS 2 BP 199 EP 208 DI 10.1061/(ASCE)0893-1321(1994)7:2(199) PG 10 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA QU051 UT WOS:A1994QU05100006 ER PT J AU RULE, WK THOMAS, FP AF RULE, WK THOMAS, FP TI WELDED-JOINTS FOR ROBOTIC, ON-ORBIT ASSEMBLY OF SPACE STRUCTURES SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB A preliminary design concept for a weldable joint for on-orbit assembly of large space structures is described. The joint was designed for ease of assembly, for structural efficiency, and to allow passage of fluid (for active cooling or other purposes) along the member through the joint. The members were assumed to consist of graphite/epoxy tubes to which were bonded 2219-T87 aluminum alloy end fittings for welding on-orbit to nodes of the same alloy. A modified form of gas tungsten arc welding was assumed to be the welding process. The joint was designed for the thermal and structural loading associated with a 37 m diameter tetrahedral truss intended as an aerobrake for a mission to Mars. It was concluded that the assembly process could lock large loads into the truss members and that the assembly robot could be required to exert large forces while aligning pairs of nodes during assembly. It was also concluded that the connections between the composite struts and the aluminum fittings will be subjected to very high service stresses due to the effects of differential thermal expansion. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT DEV BRANCH,HUNTSVILLE,AL 35812. RP RULE, WK (reprint author), UNIV ALABAMA,DEPT ENGN MECH,TUSCALOOSA,AL 35487, USA. NR 22 TC 2 Z9 3 U1 0 U2 3 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 1994 VL 7 IS 2 BP 209 EP 224 DI 10.1061/(ASCE)0893-1321(1994)7:2(209) PG 16 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA QU051 UT WOS:A1994QU05100007 ER PT J AU NAGASUBRAMANIAN, G ATTIA, AI HALPERT, G AF NAGASUBRAMANIAN, G ATTIA, AI HALPERT, G TI A POLYACRYLONITRILE-BASED GELLED ELECTROLYTE - ELECTROCHEMICAL KINETIC-STUDIES SO JOURNAL OF APPLIED ELECTROCHEMISTRY LA English DT Article ID POLY(ETHYLENE OXIDE); IONIC-CONDUCTIVITY; INTERFACE AB The bulk and interfacial properties of thin films of a polyacrylonitrile-based (PAN-based) gelled electrolyte, which was tested in conjunction with lithium electrodes, were evaluated at room temperature. The typical composition of the gelled electrolyte (GE) studied was PAN (9.13 wt %); propylene carbonate, or PC (84.87 wt %); and LiBF4 (6 wt %). A.c. and d.c. measurements were used to determine the bulk conductivity and the interfacial apparent charge-transfer resistance (R(act) of the GE. While the bulk conductivity remains stable at around 10(-3) S cm-1, the R(act) varies initially before reaching a steady value. The steady R(act) value obtained from the electrochemical measurements is near 1000 OMEGA cm2. The plating/stripping efficiency of lithium, from potentiostatic and galvanostatic measurements, is 70 to 80%. RP NAGASUBRAMANIAN, G (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 37 Z9 37 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0021-891X J9 J APPL ELECTROCHEM JI J. Appl. Electrochem. PD APR PY 1994 VL 24 IS 4 BP 298 EP 302 PG 5 WC Electrochemistry SC Electrochemistry GA NF900 UT WOS:A1994NF90000003 ER PT J AU GAO, BC WISCOMBE, WJ AF GAO, BC WISCOMBE, WJ TI SURFACE-INDUCED BRIGHTNESS TEMPERATURE-VARIATIONS AND THEIR EFFECTS ON DETECTING THIN CIRRUS CLOUDS USING IR EMISSION CHANNELS IN THE 8-12-MU-M REGION SO JOURNAL OF APPLIED METEOROLOGY LA English DT Note ID WINDOW AB A method for detecting cirrus clouds in terms of brightness temperature differences between narrowbands at 8, 11, and 12 mum has been proposed by Ackerman et al. In this method, the variation of emissivity with wavelength for different surface targets was not taken into consideration. Based on state-of-the-art laboratory measurements of reflectance spectra of terrestrial materials by Salisbury and D'Aria, it is found that the brightness temperature differences between the 8- and 11-mum bands for soils, rocks and minerals, and dry vegetation can vary between approximately -8 and +8 K due solely to surface emissivity variations. The large brightness temperature differences are sufficient to cause false detection of cirrus clouds from remote sensing data acquired over certain surface targets using the 8-11-12-mum method directly. It is suggested that the 8-11-12-mum method should be improved to include the surface emissivity effects. In addition, it is recommended that in the future the variation of surface emissivity with wavelength should be taken into account in algorithms for retrieving surface temperatures and low-level atmospheric temperature and water vapor profiles. C1 NASA,GODDARD SPACE FLIGHT CTR,CLIMATE & RADIAT BRANCH,GREENBELT,MD 20771. RP GAO, BC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 913,GREENBELT,MD 20771, USA. RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 6 TC 7 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1994 VL 33 IS 4 BP 568 EP 570 DI 10.1175/1520-0450(1994)033<0568:SIBTVA>2.0.CO;2 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NF271 UT WOS:A1994NF27100012 ER PT J AU PLOUTZ, LL TESCH, PA BIRO, RL DUDLEY, GA AF PLOUTZ, LL TESCH, PA BIRO, RL DUDLEY, GA TI EFFECT OF RESISTANCE TRAINING ON MUSCLE USE DURING EXERCISE SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE MAGNETIC RESONANCE IMAGING; NEUROMUSCULAR ADAPTATION ID CROSS-SECTIONAL AREA; HUMAN SKELETAL-MUSCLE; MOTOR UNITS; FIBER TYPES; STRENGTH; FORCE; IMAGES; SPECTROSCOPY; ADAPTATIONS; TIME AB This study examined the effect of resistance training on exercise-induced contrast shift in magnetic resonance (MR) images. It was hypothesized that a given load could be lifted after training with less muscle showing contrast shift, thereby suggesting less muscle was used to perform the exercise. Nine males trained the left quadriceps femoris (QF) muscle 2 days/wk for 9 wk using 3-6 sets of 12 knee extensions each day. The right QF served as a ''control.'' Exercise-induced contrast shifts in MR images evoked by each of three bouts of exercise (5 sets of 10 knee extensions with a load equal to 50, 75, and 100% of the maximum pretraining load that could be lifted for 5 sets of 10 repetitions) were quantified pre- and posttraining. MR image contrast shift was quantified by determining QF cross-sectional area (CSA) showing increased spin-spin relaxation time. One repetition maximum increased 14% in the left trained QF and 7% in the right untrained QF. Left QF CSA increased 5%, with no change in right QF CSA. Left QF CSA showing contrast shift was less after each bout of the exercise test posttraining. This was also true, to a lesser extent, for the right QF at the higher two loads. The results suggest that short-term resistance training reduces MR image contrast shift evoked by a given effort, thereby reflecting the use of less muscle to lift the load. Because this response was evident in both trained and contralateral untrained muscle, neural factors are suggested to be responsible. The consequence of this adaptation could be to increase ''stress'' per unit area of active muscle during the course of training and thereby evoke hypertrophy. C1 KAROLINSKA INST,DEPT PHYSIOL & PHARMACOL,S-10401 STOCKHOLM,SWEDEN. NASA,BIONET CORP,KENNEDY SPACE CTR,KENNEDY SPACE CTR,FL 32899. NASA,BIOMED OPERAT & RES OFF,KENNEDY SPACE CTR,KENNEDY SPACE CTR,FL 32899. RP PLOUTZ, LL (reprint author), OHIO UNIV,DEPT BIOL SCI,IRVINE HALL,ATHENS,OH 45701, USA. NR 44 TC 163 Z9 163 U1 1 U2 14 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD APR PY 1994 VL 76 IS 4 BP 1675 EP 1681 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA NG707 UT WOS:A1994NG70700041 PM 8045847 ER PT J AU SIDI, A AF SIDI, A TI RATIONAL-APPROXIMATIONS FROM POWER-SERIES OF VECTOR-VALUED MEROMORPHIC FUNCTIONS SO JOURNAL OF APPROXIMATION THEORY LA English DT Article ID EXTRAPOLATION METHODS; PADE APPROXIMANTS; CONVERGENCE; ALGORITHMS; SEQUENCES AB Let F(z) be a vector-valued function, F: C --> C(N), which is analytic at z = 0 and meromorphic in a neighbourhood of z = 0, and let its Maclaurin series be given. In this work we develop vector-valued rational approximation procedures for F(z) by applying vector extrapolation methods to the sequence of partial sums of its Maclaurin series. We analyze some of the algebraic and analytic properties of the rational approximations thus obtained and show that they are akin to Pade approximants. In particular, we prove a Koenig-type theorem concerning their poles and a de Montessus-type theorem concerning their uniform convergence. We show how ''optimal'' approximations to multiple poles and to Laurent expansions about these poles can be constructed. Extensions of the procedures above and the accompanying theoretical results to functions defined in arbitrary linear spaces is also considered. One of the most interesting and immediate applications of the results of this work is to the matrix eigenvalue problem. In a new work we exploit the developments of the present work to devise bona fide generalizations of the classical power method that are especially suitable for very large and sparse matrices. These generalizations can bc used to approximate simultaneously several of the largest distinct eigenvalues and corresponding eigenvectors and invariant subspaces of arbitrary matrices, which may or may not be diagonalizable, and are very closely related with known Krylov subspace methods. (C) 1994 Academic Press, Inc. C1 NASA,LEWIS RES CTR,INST COMPUTAT MECH PROPULS,CLEVELAND,OH 44135. RP SIDI, A (reprint author), TECHNION ISRAEL INST TECHNOL,DEPT COMP SCI,IL-32000 HAIFA,ISRAEL. NR 15 TC 16 Z9 22 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9045 J9 J APPROX THEORY JI J. Approx. Theory PD APR PY 1994 VL 77 IS 1 BP 89 EP 111 DI 10.1006/jath.1994.1036 PG 23 WC Mathematics SC Mathematics GA NN536 UT WOS:A1994NN53600007 ER PT J AU HAN, QY ROSSOW, WB LACIS, AA AF HAN, QY ROSSOW, WB LACIS, AA TI NEAR-GLOBAL SURVEY OF EFFECTIVE DROPLET RADII IN LIQUID WATER CLOUDS USING ISCCP DATA SO JOURNAL OF CLIMATE LA English DT Article ID REFLECTED SOLAR-RADIATION; EFFECTIVE PARTICLE RADIUS; MULTIPLE-SCATTERING; OPTICAL-THICKNESS; PLANETARY ATMOSPHERES; LIGHT-SCATTERING; CLIMATE CHANGE; CIRRUS CLOUDS; SATELLITE; STRATOCUMULUS AB A global survey of cloud particle size variations can provide crucial constraints on how cloud processes determine cloud liquid water contents and their variation with temperature, and further, may indicate the magnitude of aerosol effects on clouds. A method, based on a complete radiative transfer model for AVHRR-measured radiances, is described for retrieving cloud particle radii in liquid water clouds from satellite data currently available from the International Satellite Cloud Climatology Project. Results of sensitivity tests and validation studies provide error estimates. AVHRR data from NOAA-9 and NOAA-10 have been analyzed for January, April, July, and October in 1987 and 1988. The results of this first survey reveal systematic continental and maritime differences and hemispheric contrasts that are indicative of the effects of associated aerosol concentration differences: cloud droplet radii in continental water clouds are about 2-3 mum smaller than in marine clouds, and droplet radii are about 1 mum smaller in marine clouds of the Northern Hemisphere than in the Southern Hemisphere. The height dependencies of cloud droplet radii in continental and marine clouds are also consistent with differences in the vertical profiles of aerosol concentration. Significant seasonal and diurnal variations of effective droplet radii are also observed, particularly at lower latitudes. Variations of the relationship between cloud optical thickness and droplet radii may indicate variations in cloud microphysical regimes. C1 COLUMBIA UNIV,NEW YORK,NY 10027. GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RI Lacis, Andrew/D-4658-2012; Rossow, William/F-3138-2015 NR 99 TC 384 Z9 401 U1 3 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1994 VL 7 IS 4 BP 465 EP 497 DI 10.1175/1520-0442(1994)007<0465:NGSOED>2.0.CO;2 PG 33 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NG434 UT WOS:A1994NG43400001 ER PT J AU OSE, T MECHOSO, CR HALPERN, D AF OSE, T MECHOSO, CR HALPERN, D TI A COMPARISON BETWEEN GENERAL-CIRCULATION MODEL SIMULATIONS USING 2 SEA-SURFACE TEMPERATURE DATASETS FOR JANUARY 1979 SO JOURNAL OF CLIMATE LA English DT Article ID NORTH PACIFIC; WINTER; ANOMALIES; BLOCKING; SST AB Simulations with the UCLA atmospheric general circulation model (AGCM) using two different global sea surface temperature (SST) datasets for January 1979 are compared. One of these datasets is based on COADS (SSTs) at locations where there are ship reports, and climatology elsewhere; the other is derived from measurements by instruments onboard NOAA satellites. In the former dataset (COADS SST), data are concentrated along shipping routes in the Northern Hemisphere; in the latter dataset (HIRS SST), data cover the global domain. Ensembles of five 30-day mean fields are obtained from integrations performed in the perpetual-January mode. The results are presented as anomalies, that is, departures of each ensemble mean from that produced in a control simulation with climatological SSTs. Large differences are found between the anomalies obtained using COADS and HIRS SSTs, even in the Northern Hemisphere where the datasets are most similar to each other. The internal variability of the circulation in the control simulation and the simulated atmospheric response to anomalous forcings appear to be linked in that the pattern of geopotential height anomalies obtained using COADS SSTs resembles the first empirical orthogonal function (EOF 1) in the control simulation. The corresponding pattern obtained using HIRS SSTs is substantially different and somewhat resembles EOF 2 in the sector from central North America to central Asia. To gain insight into the reasons for these results, three additional simulations are carried out with SST anomalies confined to regions where COADS SSTs are substantially warmer than HIRS SSTs. The regions correspond to warm pools in the northwest and northeast Pacific, and the northwest Atlantic. These warm pools tend to produce positive geopotential height anomalies in the northeastern part of the corresponding oceans. Both warm pools in the Pacific produce large-scale circulation anomalies with a pattern that resembles that obtained using COADS SSTs as well as EOF 1 of the control simulation; the warm pool in the Atlantic does not. These results suggest that the differences obtained with COADS SSTs and HIRS SSTs are mostly due to the differences in the datasets over the northern Pacific. There was a blocking episode near Greenland in late January 1979. Both simulations with warm SST anomalies over the northwest and northeast Pacific show a tendency toward increased incidence of North Atlantic blocking; the simulation with warm SST anomalies over the northwest Atlantic shows a tendency toward decreased incidence. These results suggest that features in both SST datasets that do not have a counterpart in the other dataset contribute significantly to the differences between the simulated and observed fields. The results of this study imply that uncertainties in current SST distributions for the world oceans can be as important as the SST anomalies themselves in terms of their impact on the atmospheric circulation. Caution should be exercised, therefore, when linking anomalous circulation and SST patterns, especially in long-range prediction. C1 UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,405 HILGARD AVE,LOS ANGELES,CA 90024. JET PROP LAB,PASADENA,CA 91109. NR 16 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1994 VL 7 IS 4 BP 498 EP 505 DI 10.1175/1520-0442(1994)007<0498:ACBGCM>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NG434 UT WOS:A1994NG43400002 ER PT J AU JOHNSON, WS OBRIEN, TK MASTERS, JE AF JOHNSON, WS OBRIEN, TK MASTERS, JE TI STINCHCOMB,WAYNE,W. - IN-MEMORIAM SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Item About an Individual C1 LOCKHEED ENGN & SCI,HAMPTON,VA 23666. USA,VEHICLE STRUCT DIRECTORATE,HAMPTON,VA 23681. RP JOHNSON, WS (reprint author), NASA,LANGLEY RES CTR,NS 188E,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD APR PY 1994 VL 16 IS 2 BP 101 EP 101 PG 1 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA NF977 UT WOS:A1994NF97700001 ER PT J AU ZALAMEDA, JN FARLEY, GL SMITH, BT AF ZALAMEDA, JN FARLEY, GL SMITH, BT TI A FIELD DEPLOYABLE NONDESTRUCTIVE IMPACT DAMAGE ASSESSMENT METHODOLOGY FOR COMPOSITE STRUCTURES SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE THROUGH-THE-THICKNESS (TTT) REINFORCEMENT; THERMAL NONDESTRUCTIVE EVALUATION (NDE); ULTRASONIC VOLUMETRIC IMAGING; COMPOSITES AB A technique is being developed for rapid in-service detection and quantification of damage in composite airframe structures combining thermal and ultrasonic nondestructive evaluation (NDE). Thermal inspection techniques can be used to identify impact damage areas because it is fast, inspects large areas, and is noncontacting. Once an area of concern is identified, characterization of the depth and extent of the damage can be determined using ultrasonic volumetric imaging. Ultrasonic volumetric imaging quantifies the damage by giving a ply-by-ply view of the damage. Single-sided measurements were made on two types of samples, flat panels with through-the-thickness reinforcements and a ''Y''-stiffened skin. These samples were impacted with an aluminum ball at various velocities. The thermal results were compared with ultrasonic C-scans and the ultrasonic volumetric results were compared with destructive tests. The thermal images compared well with the C-scan images in both relative size and shape. It was found that the ultrasonic volumetric results gave a better indication of damage than achievable with the destructive specimen evaluation method. It has been shown that a multidisciplinary approach using thermal and ultrasonic NDE techniques is an efficient and informative inspection method for identifying and quantifying damage. C1 COLL WILLIAM & MARY,WILLIAMSBURG,VA 23185. RP ZALAMEDA, JN (reprint author), USA,RES LAB,VEHICLE STRUCT DIRECTORATE,NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 10 TC 2 Z9 3 U1 1 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD APR PY 1994 VL 16 IS 2 BP 161 EP 169 PG 9 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA NF977 UT WOS:A1994NF97700008 ER PT J AU CARPENTER, MH GOTTLIEB, D ABARBANEL, S AF CARPENTER, MH GOTTLIEB, D ABARBANEL, S TI TIME-STABLE BOUNDARY-CONDITIONS FOR FINITE-DIFFERENCE SCHEMES SOLVING HYPERBOLIC SYSTEMS - METHODOLOGY AND APPLICATION TO HIGH-ORDER COMPACT SCHEMES SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID APPROXIMATIONS; STABILITY AB We present a systematic method for constructing boundary conditions (numerical and physical) of the required accuracy, for compact (Pade-like) high-order finite-difference schemes for hyperbolic systems. First a proper summation-by-parts formula is found for the approximate derivative. A ''simultaneous approximation term'' is then introduced to treat the boundary conditions. This procedure leads to time-stable schemes even in the system case. An explicit construction of the fourth-order compact case is given. Numerical studies are presented to verify the efficacy of the approach. (C) 1994 Academic Press, Inc. C1 BROWN UNIV,DIV APPL MATH,PROVIDENCE,RI 02912. TEL AVIV UNIV,SCH MATH SCI,DEPT APPL MATH,IL-69978 TEL AVIV,ISRAEL. RP CARPENTER, MH (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23681, USA. NR 9 TC 223 Z9 225 U1 0 U2 9 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR PY 1994 VL 111 IS 2 BP 220 EP 236 DI 10.1006/jcph.1994.1057 PG 17 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA NK226 UT WOS:A1994NK22600002 ER PT J AU SZEWCZYK, ZP HAJELA, P AF SZEWCZYK, ZP HAJELA, P TI DAMAGE DETECTION IN STRUCTURES BASED ON FEATURE-SENSITIVE NEURAL NETWORKS SO JOURNAL OF COMPUTING IN CIVIL ENGINEERING LA English DT Article ID DESIGN AB Detection of damage in structural systems is formulated as an inverse problem and solved by a new approach utilizing neural networks. Damage is modeled through reduction in the stiffness of structural elements, and manifests itself in the form of variations in observable static displacements under prescribed loads. A modified counterpropagation neural network is used to develop the inverse mapping between a vector of the stiffness of individual structural elements and the vector of the global static displacements under a testing load. It is shown that the network functions as an associative memory device capable of satisfactory diagnostics even in the presence of noisy or incomplete measurements. Numerical examples involving frame and truss structures show that the network approximations are fully acceptable from a practical standpoint. C1 RENSSELAER POLYTECH INST,DEPT MECH ENGN AERONAUT ENGN & MECH,TROY,NY 12180. RP SZEWCZYK, ZP (reprint author), NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681, USA. NR 9 TC 78 Z9 80 U1 0 U2 3 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0887-3801 J9 J COMPUT CIVIL ENG JI J. Comput. Civil. Eng. PD APR PY 1994 VL 8 IS 2 BP 163 EP 178 DI 10.1061/(ASCE)0887-3801(1994)8:2(163) PG 16 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA QA966 UT WOS:A1994QA96600004 ER PT J AU ROGERS, JL AF ROGERS, JL TI SIMULATING STRUCTURAL-ANALYSIS WITH NEURAL-NETWORK SO JOURNAL OF COMPUTING IN CIVIL ENGINEERING LA English DT Article AB Structural analysis programs used in solving design problems are often computationally expensive. Obtaining optimal solutions typically requires numerous iterations involving analysis and optimization programs. This process becomes prohibitive due to the amount of computer time required for convergence to an optimum design. Any new techniques significantly reducing the computer time required to solve design problems would be beneficial. One promising technique is to simulate a slow, expensive structural analysis program with a fast, inexpensive neural network. Guidelines for designing and training a neural network to simulate a structural analysis program are developed. These guidelines include the selection of training pairs and determining the number of nodes on the hidden layer. A sample problem shows that by following these guidelines, a neural network can reduce the amount of time it takes an optimization process to converge to an optimum design. RP ROGERS, JL (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 18 TC 46 Z9 46 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0887-3801 J9 J COMPUT CIVIL ENG JI J. Comput. Civil. Eng. PD APR PY 1994 VL 8 IS 2 BP 252 EP 265 DI 10.1061/(ASCE)0887-3801(1994)8:2(252) PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA QA966 UT WOS:A1994QA96600009 ER PT J AU BIAO, Y AZOULAY, M GEORGE, MA BURGER, A COLLINS, WE SILBERMAN, E SU, CH VOLZ, ME SZOFRAN, FR GILLIES, DC AF BIAO, Y AZOULAY, M GEORGE, MA BURGER, A COLLINS, WE SILBERMAN, E SU, CH VOLZ, ME SZOFRAN, FR GILLIES, DC TI PHOTOLUMINESCENCE OF VAPOR AND SOLUTION-GROWN ZNTE SINGLE-CRYSTALS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 6th International Conference on I-VI Compounds and Related Optoelectronic Materials CY SEP 13-17, 1993 CL NEWPORT, RI ID ACCEPTOR AB ZnTe single crystals grown by horizontal physical vapor transport (PVT) and by vertical traveling heater method (THM) from a Te solution were characterized by photoluminescence (PL) at 10.6 K and by atomic force microscopy (AFM). Copper was identified by PL as a major impurity existing in both crystals, forming a substitutional acceptor, Cu(Zn). The THM ZnTe crystals were found to contain more Cu impurity than the PVT ZnTe crystals. The formation of Cu(Zn)-V(Te) complexes and the effects of annealing, oxygen contamination and intentional Cu doping were also studied. Finally, the surface morphology analyzed by AFM was correlated to the PL results. C1 FISK UNIV,CTR PHOTON MAT & DEVICES,DEPT PHYS,NASHVILLE,TN 37208. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NR 10 TC 21 Z9 22 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1994 VL 138 IS 1-4 BP 219 EP 224 DI 10.1016/0022-0248(94)90810-9 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA NN997 UT WOS:A1994NN99700041 ER PT J AU KORPELA, SA CHAIT, A MATTHIESEN, DH AF KORPELA, SA CHAIT, A MATTHIESEN, DH TI LATERAL OR RADIAL SEGREGATION IN SOLIDIFICATION OF BINARY ALLOY WITH A CURVED LIQUID-SOLID INTERFACE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID DIRECTIONAL SOLIDIFICATION AB This paper deals with steady state lateral or radial segregation of solute in solidification of a binary alloy with a curved solid-liquid interface. It is an extension of the work of Coriell and Sekerka and of Coriell et al. for interface shapes that meet the crucible wall at an arbitrary angle, as is commonly found in experiments. This work is limited to the diffusion controlled growth regime in which the Peclet number Pe = Vl/D is large, and where the interface deflection is small. In the definition of Peclet number V is the growth rate, l is a characteristic length, and D is the binary diffusion coefficient of the solute in the liquid. We present analytical expressions for lateral and radial segregation which can be readily evaluated, given the material properties, growth velocity, and an interface shape obtained from experiment. C1 NASA,LEWIS RES CTR,2100 BROOKPARK RD,CLEVELAND,OH 44135. OHIO STATE UNIV,COLUMBUS,OH 43210. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. NR 7 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1994 VL 137 IS 3-4 BP 623 EP 632 DI 10.1016/0022-0248(94)91007-3 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA NE892 UT WOS:A1994NE89200040 ER PT J AU PINDERA, MJ FREED, AD AF PINDERA, MJ FREED, AD TI THE EFFECT OF MATRIX MICROSTRUCTURE ON THERMALLY-INDUCED RESIDUAL-STRESSES IN SIC/TITANIUM ALUMINIDE COMPOSITES SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID MICROMECHANICAL ANALYSIS AB This paper examines the effect of varying the microstructural composition of titanium aluminide on the evolution of residual stresses in titanium aluminide matrix composites. An analytical model is developed to determine residual stresses in fiber and matrix phases of unidirectional, SiC/Ti-Al composites subjected to axisymmetric thermal loading. The model uses elements of the concentric cylinder model and the method of cells to calculate residual thermal stresses in the presence of temperature-dependent and inelastic behavior of the fiber and matrix phases. The concentric cylinder model is employed as a geometric model for the unidirectional composite, whereas the method of cells is employed in modeling the microstructure of the titanium aluminide matrix phase. The titanium aluminide matrix consists of distinct brittle and ductile alpha and beta phases whose volume content is varied in the present scheme to understand how the resulting residual stresses can be altered. Both spatially uniform and nonuniform variations of the alpha and beta phases are considered. The results explain the occurrence of radial microcracks in SiC/Ti-Al composites in the presence of a beta-depleted region at the fiber/matrix interface, and validate the potential of engineering the matrix phase to reduce residual stresses in these composites. C1 NASA,LEWIS RES CTR,PROC SCI & TECHNOL BRANCH,CLEVELAND,OH 44135. RP PINDERA, MJ (reprint author), UNIV VIRGINIA,DEPT CIVIL ENGN & APPL MECH,CHARLOTTESVILLE,VA 22903, USA. NR 15 TC 13 Z9 13 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1994 VL 116 IS 2 BP 215 EP 221 DI 10.1115/1.2904276 PG 7 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA NH491 UT WOS:A1994NH49100013 ER PT J AU FRIEDMAN, R KENNEDY, J ROYSTER, D AF FRIEDMAN, R KENNEDY, J ROYSTER, D TI ANALYSIS AND COMPRESSION TESTING OF 2024-ALUMINUM AND 8009-ALUMINUM ALLOY ZEE-STIFFENED PANELS SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article AB Zee-stiffened compression test panels, fabricated with dispersion-strengthened, high-temperature 8009 aluminum alloy sheet, were evaluated to determine the alloy's feasibility for compression-critical applications. A compression panel design configuration was obtained using a strength analysis program that predicts the post-skin buckling strength of flat or curved-skinned, metallic-stiffened structure. Three short-column panels were tested to failure at room temperature: (a) a baseline riveted panel fabricated with 2024-T62 aluminum zee stringers and a 2024-T81 aluminum skin, (b) a riveted panel fabricated with 8009 aluminum zee stringers and skin, and (c) a resistance spot-welded panel fabricated with 8009 aluminum zee stringers and skin. The 8009 alloy exhibited pronounced, compressive strength anisotropy, necessitating panel orientation to take advantage of the higher compressive yield in the sheet transverse direction. Compression test results were in good agreement with the predicted compression allowables since they were within 5 percent of the test strength. The 8009 aluminum riveted panel exhibited superior skin buckling resistance and failed in the wrinkling mode, as predicted, at a load approximately 15 percent higher than that of the baseline 2024 panel. The spotwelded 8009 panel did not fail in the wrinkling mode since the spot welds failed in tension shortly after the skin locally buckled. The latter test indicates that the spot welded skin-stringer combinations should not be used above the buckling stress. Due to its excellent microstructural stability at elevated temperatures, high-temperature compression panels of 8009 alloy offer potential weight savings of 25 percent compared with conventional aluminum alloys. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP FRIEDMAN, R (reprint author), GRUMMAN AEROSP CORP,BETHPAGE,NY 11714, USA. NR 14 TC 0 Z9 0 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1994 VL 116 IS 2 BP 238 EP 243 DI 10.1115/1.2904279 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA NH491 UT WOS:A1994NH49100016 ER PT J AU BRILL, RW JONES, DR AF BRILL, RW JONES, DR TI THE INFLUENCE OF HEMATOCRIT, TEMPERATURE AND SHEAR RATE ON THE VISCOSITY OF BLOOD FROM HIGH-ENERGY-DEMAND TELEOST, THE YELLOWFIN TUNA THUNNUS ALBACARES SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE BLOOD; VISCOSITY; HEMATOCRIT; YELLOWFIN TUNA; THUNNUS ALBACARES ID OXYGEN-TRANSPORT; KATSUWONUS-PELAMIS; SKIPJACK TUNA; RAINBOW-TROUT; BEHAVIORAL THERMOREGULATION; PLASMA VISCOSITY; METABOLIC RATES; WINTER FLOUNDER; ACUTE-HYPOXIA; FISH AB The high cardiac output, arterial blood pressure and cardiac energy demand of tuna make it likely that blood viscosity has an important influence on cardiovascular function. Furthermore, tuna regularly subject themselves to ambient temperature changes of 10 degrees C or more during their daily vertical migrations. They can also maintain muscle temperatures several degrees Celsius above ambient and reach maximum muscle temperatures of approximately 15 degrees C above ambient. The blood of tuna is, therefore, subjected to more frequent and rapid temperature changes than those that occur in other teleosts. Nothing is known, however, about the effects of temperature, shear rate or hematocrit on the viscosity of tuna blood. Viscosity of yellowfin tuna blood (hematocrits of 0-55%) was measured at 15, 25 and 35 degrees C and at shear rates of 45, 90, 225 and 450 s(-1) using a cone-plate viscometer. As found for the blood of other vertebrates, viscosity increased with increasing hematocrit. Viscosity also increased nonlinearly with decreasing shear rate, until a shear rate of 90s(-1) was reached. There was no significant increase in viscosity when shear rate was decreased further, to 45 s(-1). Because of the relatively flat hematocrit-viscosity curves, predicted optimal hematocrit curves were nearly flat above a hematocrit of approximately 30%. RP BRILL, RW (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822, USA. NR 54 TC 10 Z9 12 U1 0 U2 3 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE, CAMBS, ENGLAND CB4 4DL SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD APR PY 1994 VL 189 BP 199 EP 212 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA NF093 UT WOS:A1994NF09300012 ER PT J AU FOLK, CL REMINGTON, RW WRIGHT, JH AF FOLK, CL REMINGTON, RW WRIGHT, JH TI THE STRUCTURE OF ATTENTION CONTROL - CONTINGENT ATTENTIONAL CAPTURE BY APPARENT MOTION, ABRUPT ONSET, AND COLOR SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID VISUAL-SEARCH; PERCEPTUAL SELECTIVITY; CONJUNCTION SEARCH; CONTROL SETTINGS; GUIDED SEARCH; SHORT-RANGE; MODEL; SEGREGATION; MECHANISMS; VOLUNTARY AB Five spatial cuing experiments tested 2 hypotheses regarding attentional capture: (a) Attentional capture is contingent on endogenous attentional control settings, and (b) attentional control settings are limited to the distinction between dynamic and static discontinuities (C. L. Folk, R. W. Remington, & J. C. Johnston, 1992). In Experiments 1 and 2, apparent-motion precues produced significant costs in performance for targets signaled by motion but not for targets signaled by color or abrupt onset. Experiment 3 established that this pattern is not due to differences in the difficulty of target discrimination. Experiments 4 and 5 revealed asymmetric capture effects between abrupt onset and apparent motion related to stimulus salience. The results support the hypotheses of Folk et al. (1992) and suggest that stimulus salience may also play a role in attentional capture. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP FOLK, CL (reprint author), VILLANOVA UNIV,DEPT PSYCHOL,VILLANOVA,PA 19085, USA. NR 39 TC 366 Z9 371 U1 3 U2 27 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 SN 0096-1523 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD APR PY 1994 VL 20 IS 2 BP 317 EP 329 DI 10.1037/0096-1523.20.2.317 PG 13 WC Psychology; Psychology, Experimental SC Psychology GA ND138 UT WOS:A1994ND13800007 PM 8189195 ER PT J AU DELCOURT, DC MOORE, TE CHAPPELL, CR AF DELCOURT, DC MOORE, TE CHAPPELL, CR TI CONTRIBUTION OF LOW-ENERGY IONOSPHERIC PROTONS TO THE PLASMA SHEET SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID POLAR WIND; ION-BEAMS; NONLINEAR DYNAMICS; BOUNDARY-LAYER; FIELD; MAGNETOSPHERE; ACCELERATION; MAGNETOTAIL; MODEL; DISTRIBUTIONS AB The magnetospheric transport of low-energy ionospheric ions is examined by means of three-dimensional particle codes. Emphasis is placed on the behavior of polar wind and cleft originating protons. It is demonstrated that, via nonadiabatic motion inside the neutral sheet, these ions can significantly contribute to the populations of the plasma sheet. The importance of this contribution is found to depend critically upon the dynamics of particles originating from the highest latitudes, as these possibly have access to the distant tail. Hence it is shown that polar wind H+ expelled into the magnetosphere at very low energies (in the electron volt range) preferentially feed the plasma sheet during quiet times, experiencing accelerations up to several kiloelectron volts upon return into the inner magnetosphere. In contrast, during disturbed times, the intensifying magnetospheric convection confines this population to low L shells where it travels in a nearly adiabatic manner. As for the protons originating from the cleft fountain, the simulations reveal that they can be transported up to the vicinity of the distant neutral line in the nightside sector. Via interaction with the neutral sheet, these ionospheric ions are rapidly raised to the characteristic plasma sheet energy range. The density levels contributed by these populations are quite substantial when compared to those measured in situ. These simulations establish an active role of low-energy ionospheric ions in the overall magnetospheric dynamics. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP DELCOURT, DC (reprint author), CNET,CRPE,CNRS,4 AVE NEPTUNE,F-94107 ST MAUR FOSSES,FRANCE. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 40 TC 32 Z9 32 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5681 EP 5689 DI 10.1029/93JA02770 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000001 ER PT J AU GANGULI, SB MITCHELL, HG PALMADESSO, PJ AF GANGULI, SB MITCHELL, HG PALMADESSO, PJ TI AURORAL PLASMA TRANSPORT PROCESSES IN THE PRESENCE OF KV POTENTIAL STRUCTURES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRIC-FIELDS; PARTICLE; DISTRIBUTIONS; REGION; DRIVEN AB We have simulated plasma transport processes in the presence of a quasi-twodimensional current filament, that generated kV potential structure in the auroral region. The simulation consists of a set of one-dimensional flux tube simulations with different imposed time-dependent, field-aligned currents. The model uses the 16 moment system of equations and simultaneously solves coupled continuity and momentum equations and equations describing the transport along the magnetic field lines of parallel and perpendicular thermal energy and heat flows for each species. The lower end of the simulation is at an altitude of 800 km, in the collisional topside ionosphere, while the upper end is at 10R(E) in the magnetosphere. The plasma consists of hot electrons and protons of magnetospheric origin and low-energy electrons, protons, and oxygen ions of ionospheric origin. The dynamical interaction of the individual current filaments with ionospheric and magnetospheric plasma generates a potential structure in the horizontal direction and kilovolt field-aligned potential drops along the field lines. The side-by-side display exhibits the evolution of the implied potential structure in the horizontal direction. In the presence of this potential structure and parallel electric field the ionospheric plasma density is depleted and velocity is reduced, while density enhancement and increased velocity is observed in magnetospheric plasma. The ionospheric and magnetospheric electron temperatures increase below 2R(E) due to magnetic mirror force on converging geomagnetic field lines. The primary cross-field motion produced by the horizontal E field (E x B drift) is perpendicular to both of the significant spatial directions and is thus ignorable in this geometry. The effects of other cross-field drift processes are discussed. The simulation thus provides insight into the dynamical evolution of two-dimensional potential structures driven by an imposed finite width, field-aligned current profile. C1 NASA,GODDARD SPACE FLIGHT CTR,DIV SPACE DATA & COMP,GREENBELT,MD 20771. USN,RES LAB,DIV PLASMA PHYS,WASHINGTON,DC 20375. RP GANGULI, SB (reprint author), SCI APPLICAT INT CORP,DIV PLASMA PHYS,1710 GOODRIDGE DR,MCLEAN,VA 22102, USA. NR 21 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5761 EP 5770 DI 10.1029/93JA02773 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000007 ER PT J AU GONZALEZ, WD JOSELYN, JA KAMIDE, Y KROEHL, HW ROSTOKER, G TSURUTANI, BT VASYLIUNAS, VM AF GONZALEZ, WD JOSELYN, JA KAMIDE, Y KROEHL, HW ROSTOKER, G TSURUTANI, BT VASYLIUNAS, VM TI WHAT IS A GEOMAGNETIC STORM SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Review ID INTERPLANETARY MAGNETIC-FIELD; CORONAL MASS EJECTA; PHASE RING CURRENT; SOLAR-WIND; MAGNETOSPHERIC SUBSTORMS; SEMIANNUAL VARIATION; MEDIUM PARAMETERS; RADIAL DIFFUSION; ENERGY; MODEL AB After a brief review of magnetospheric and interplanetary phenomena for intervals with enhanced solar wind-magnetosphere interaction, an attempt is made to define a geomagnetic storm as an interval of time when a sufficiently intense and long-lasting interplanetary convection electric field leads, through a substantial energization in the magnetosphere-ionosphere system, to an intensified ring current sufficiently strong to exceed some key threshold of the quantifying storm time Dst index. The associated storm/substorm relationship problem is also reviewed. Although the physics of this relationship does not seem to be fully understood at this time, basic and fairly well established mechanisms of this relationship are presented and discussed. Finally, toward the advancement of geomagnetic storm research, some recommendations are given concerning future improvements in monitoring existing geomagnetic indices as well as the solar wind near Earth. C1 NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA 442, JAPAN. NOAA, NATL GEOPHYS DATA CTR, BOULDER, CO 80303 USA. UNIV ALBERTA, DEPT PHYS, EDMONTON T6G 2G1, ALBERTA, CANADA. JET PROP LAB, PASADENA, CA 91109 USA. MAX PLANCK INST AERON, W-3411 KATLENBURG DUHM, GERMANY. RP NOAA, ENVIRONM RES LAB, 325 BROADWAY, BOULDER, CO 80303 USA. NR 141 TC 837 Z9 862 U1 13 U2 83 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5771 EP 5792 DI 10.1029/93JA02867 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000008 ER PT J AU PULKKINEN, TI BAKER, DN MITCHELL, DG MCPHERRON, RL HUANG, CY FRANK, LA AF PULKKINEN, TI BAKER, DN MITCHELL, DG MCPHERRON, RL HUANG, CY FRANK, LA TI THIN CURRENT SHEETS IN THE MAGNETOTAIL DURING SUBSTORMS - CDAW-6 REVISITED SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOSPHERIC MAGNETIC-FIELD; TAIL CURRENT SHEET; GEOMAGNETIC TAIL; GROWTH-PHASE; MARCH 22; DYNAMICS; INTERVALS AB The global magnetic field configuration during the growth phase of the CDAW 6 substrom (March 22, 1979, 1054 UT) is modeled using data from two suitably located spacecraft and temporally evolving variations of the Tsyganenko magnetic field model. These results are compared with a local calculation of the current sheet location and thickness carried out by McPherron et al. (1987) and Sanny et al. (this issue). Both models suggest that during the growth phase the current sheet rotated away from its nominal location, and simultaneously thinned strongly. The locations and thicknesses obtained from the two models are in good agreement. The global model suggests that the peak current density is approximately 120 nA/m2, and that the cross-tail current almost doubled its intensity during this very strong growth phase. The global model predicts a field configuration that is sufficiently stretched to scatter thermal electrons, which may be conducive to the onset of ion tearing in the tail. The electron plasma data further support this scenario, as the anisotropy present in the low-energy electrons disappears close to the substorm onset. The electron contribution to the intensifying current in this case is of the order of 10% before the isotropization of the distribution. C1 JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP PULKKINEN, TI (reprint author), FINNISH METEOROL INST,BOX 503,SF-00101 HELSINKI,FINLAND. RI Pulkkinen, Tuija/D-8403-2012 OI Pulkkinen, Tuija/0000-0002-6317-381X NR 24 TC 74 Z9 75 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5793 EP 5803 DI 10.1029/93JA03234 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000009 ER PT J AU SANNY, J MCPHERRON, RL RUSSELL, CT BAKER, DN PULKKINEN, TI NISHIDA, A AF SANNY, J MCPHERRON, RL RUSSELL, CT BAKER, DN PULKKINEN, TI NISHIDA, A TI GROWTH-PHASE THINNING OF THE NEAR-EARTH CURRENT SHEET DURING THE CDAW-6 SUBSTORM SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD; PLASMA SHEET; MARCH 22; MAGNETOTAIL; TAIL AB The thinning of the near-Earth current sheet during the growth phase of the CDAW 6 magnetospheric substorm is studied. The expansion onset of the substorm occurred at 1054 UT, March 22, 1979. During the growth phase, two spacecraft, ISEE 1 and ISEE 2, were within the current sheet approximately 13R(E) from the Earth and obtained simultaneous high-resolution magnetic data at two points in the current sheet. Plasma data were also provided by the ISEE spacecraft and solar wind data by IMP 8. To facilitate the analysis, the GSM magnetic field data are transformed to a ''neutral sheet coordinate system'' in which the new x axis is parallel to the average magnetic field above and below the neutral sheet and the new y axis lies in the GSM equatorial plane. A model based on the assumption that the current sheet is a time-invariant structure fails to predict neutral sheet crossing times. Consequently, the Harris sheet model, which allows one to remove the restriction of time invariancy, is used instead. It is found that during the growth phase, a model parameter corresponding to the thickness of the current sheet decreased exponentially from about 5R(E) to 1R(E) with a time constant of about 14 min. In addition, the ISEE 1 and ISEE 2 neutral sheet crossings after expansion onset indicate that the neutral sheet was moving upward at 7 km/s relative to the spacecraft. Since both crossings occurred in approximately 80 s, the current sheet thickness is estimated to be about 500 km. These results demonstrate that the near-Earth current sheet undergoes dramatic thinning during the substorm growth phase and expansion onset. C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,JAPAN. FINNISH METEOROL INST,HELSINKI,FINLAND. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SANNY, J (reprint author), LOYOLA MARYMOUNT UNIV,DEPT PHYS,LOS ANGELES,CA 90045, USA. RI Pulkkinen, Tuija/D-8403-2012; OI Pulkkinen, Tuija/0000-0002-6317-381X; Russell, Christopher/0000-0003-1639-8298 NR 32 TC 127 Z9 127 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5805 EP 5816 DI 10.1029/93JA03235 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000010 ER PT J AU BIRN, J HESSE, M AF BIRN, J HESSE, M TI INFLUENCE OF PLASMA SHEET THICKENING TOWARD THE TAIL FLANKS ON MAGNETOTAIL STABILITY AND DYNAMICS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GEOMAGNETIC TAIL; RECONNECTION; EQUILIBRIA; MECHANISM AB On the basis of resistive MHD simulations we investigate the stability and dynamic evolution of the magnetotail for configurations with various degrees of plasma sheet thickening from midnight toward the tail flanks, associated with a similar increase of the B(z) component. This increase is varied by factors between 2 and 3.5, while the magnitude of B(z) at midnight is left unchanged. The increase of B(z) has a strong effect on the spatial extent of resistive tearing and reconnection across the tail and on the unstable evolution. For stronger thickening the cross-tail extent of the near-Earth neutral line, formed by reconnection, and correspondingly the amount of reconnected magnetic flux get reduced and the dipolarization effects earthward of the neutral line are more concentrated near midnight. An increase of B(z) from midnight toward the flanks by more than a factor of about 3 can possibly even suppress the resistive tearing instability. This indicates the possibility of a stability transition due to a reduction of B(z) in the flank regions in response to changes in the solar wind, even when the magnitude of B(z) near midnight and the fluctuation level in that region are unchanged (provided that a sufficient fluctuation level exists). C1 NASA,GODDARD SPACE FLIGHT CTR,ELECTRODYNAM BRANCH,GREENBELT,MD 20771. RP BIRN, J (reprint author), LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,MS D466,LOS ALAMOS,NM 87545, USA. RI Hesse, Michael/D-2031-2012 NR 12 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 5847 EP 5853 DI 10.1029/93JA03568 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000014 ER PT J AU TAGUCHI, S SUGIURA, M IYEMORI, T WINNINGHAM, JD SLAVIN, JA AF TAGUCHI, S SUGIURA, M IYEMORI, T WINNINGHAM, JD SLAVIN, JA TI B(Y)-CONTROLLED CONVECTION AND FIELD-ALIGNED CURRENTS NEAR MIDNIGHT AURORAL OVAL FOR NORTHWARD INTERPLANETARY MAGNETIC-FIELD SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LATITUDE ELECTRIC-FIELDS; SCALE BIRKELAND CURRENTS; DEPENDENT PLASMA-FLOW; DAYSIDE POLAR-REGION; DISTANT MAGNETOTAIL; IMF-BY; Y-COMPONENT; MAGNETOSPHERIC CONVECTION; IONOSPHERIC CONVECTION; HARANG DISCONTINUITY AB Using the Dynamics Explorer (DE) 2 magnetic and electric field and plasma data, B(y)-controlled convection and field-aligned currents in the midnight sector for northward interplanetary magnetic field (IMF) are examined. The results of an analysis of the electric field data show that when IMF is stable and when its magnitude is large, a coherent B(y)-controlled convection exists near the midnight auroral oval in the ionosphere having adequate conductivities. When B(y) is negative, the convection consists of a westward (eastward) plasma flow at the lower latitudes and an eastward (westward) plasma flow at the higher latitudes in the midnight sector in the northern (southern) ionosphere. When B(y) is positive, the flow directions are reversed. The distribution of the field-aligned currents associated with the B(y)-controlled convection, in most cases, shows a three-sheet structure. In accordance with the convection the directions of the three sheets are dependent on the sign of B(y). The location of disappearance of the precipitating intense electrons having energies of a few keV is close to the convection reversal surface. However, the more detailed relationship between the electron precipitation boundary and the convection reversal surface depends on the case. In some cases the precipitating electrons extend beyond the convection reversal surface, and in others the poleward boundary terminates at a latitude lower than the reversal surface. Previous studies suggest that the poleward boundary of the electrons having energies of a few keV is not necessarily coincident with an open/closed boundary. Thus the open/closed boundary may be at a latitude higher than the poleward boundary of the electron precipitation, or it may be at a latitude lower than the poleward boundary of the electron precipitation. We discuss relationships between the open/closed boundary and the convection reversal surface. When as a possible choice we adopt a view that the open/closed boundary agrees with the convection reversal surface, we can explain qualitatively the configuration of the B(y)-controlled convection on the open and close field line regions by proposing a mapping modified in accordance with IMF B(y). C1 NASA,GODDARD SPACE FLIGHT CTR,MOLEC BIOL LAB,GREENBELT,MD 20771. KYOTO UNIV,FAC SCI,CTR GEOMAGNETISM & SPACE MAGNETISM,KYOTO 60601,JAPAN. TOKAI UNIV,INST RES & DEV,TOKYO 151,JAPAN. SW RES INST,SAN ANTONIO,TX 78284. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 54 TC 23 Z9 24 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6027 EP 6044 DI 10.1029/93JA02677 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000029 ER PT J AU REINER, MJ FAINBERG, J STONE, RG AF REINER, MJ FAINBERG, J STONE, RG TI A NEW COMPONENT OF JOVIAN KILOMETRIC RADIO-EMISSION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ASTRONOMY OBSERVATIONS; ULYSSES RADIO; JUPITER; RADIATION; POLARIZATION; ENCOUNTER; TORUS AB Evidence is presented for a new Jovian radio emission component in the frequency range from approximately 40 to approximately 200 kHz observed during the Ulysses-Jupiter outbound pass at high Jovian southern latitudes along the dusk terminator. The new radio component (referred to as sKOM) occurs in the same frequency range as the observed broadband kilometric (bKOM) radio emission, but its characteristics are distinctly different. It has the opposite polarization, is about 100 times weaker, and has a characteristically smooth intensity profile. It is consistently observed in the longitudinal range from approximately 120-degrees to approximately 230-degrees central meridian longitude, where the intermittent bKOM is often absent, and is found to originate in the Jovian magnetosphere about 5R(J) from Jupiter and at a latitude of about 35-degrees-S. Its observed right-hand circular polarization suggests that it is generated in the O mode in the source region. C1 HUGHES STX,LANHAM,MD. RP REINER, MJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 27 TC 3 Z9 3 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6137 EP 6144 DI 10.1029/93JA03398 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000036 ER PT J AU SONWALKAR, VS INAN, US BELL, TF HELLIWELL, RA MOLCHANOV, OA GREEN, JL AF SONWALKAR, VS INAN, US BELL, TF HELLIWELL, RA MOLCHANOV, OA GREEN, JL TI DE-1 VLF OBSERVATIONS DURING ACTIVITY WAVE INJECTION EXPERIMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SIPLE TRANSMITTER SIGNALS; NORMAL DIRECTION; PLASMASPHERE; SATELLITE AB We report on coordinated high-altitude satellite observations in support of one of the first space-based VLF wave injection experiments, namely the USSR Aktivny mission. The Activny satellite (A) was designed to carry a VLF transmitter (nominal frequency approximately 10 kHz, transmitter power approximately 10 kW) coupled to a 20-m-diameter loop antenna in a nearly polar orbit (83-degrees inclination, apogee approximately 2500 km, perigee approximately 500 km). We focus our attention on conjunction experiments between the Activny and DE 1 satellites. Because of problems in the deployment of the loop antenna, the radiated power capability of the antenna was significantly reduced. Although this substantially reduced the expectation of receiving detectable signal levels on the satellite, the DE 1/Activny conjunction experiments were nevertheless carried out as a means of possibly placing an upper limit on the radiated power. During the period November 1989 through April 1990, a total of 10 DE 1/Activny wave injection sessions were conducted. During each session the Activny transmitter operated at 10.537 kHz with 1 s On - 1 s Off format, for a period of 6 min centered around the conjunction time. During three conjunction periods (December 12, 26, and 27, 1989) both DE 1 and Activny were in the southern hemisphere, and DE 1 was at relatively low altitudes (ranging from 6211 to 14,810 km), thus providing the best conjunction possibilities according to the ray tracing criteria developed above. On most days, Omega transmitter signals as well as commonly occurring natural wave phenomena such as whistlers (0+) and hiss were clearly seen well above the background level, but there was no evidence of the Activny 1 s On/1 s Off pattern. Though no Activny signals were detected by the LWR on the DE 1 satellite, the experimental constraints allow us to place an upper limit on the total power radiated by the Activny transmitter in the whistler-mode. Using experimental parameters, and the minimum detectable signal level of 0.05 muV/m for LWR, we find the upper limit on the total power radiated by the Activny satellite in the whistler-mode to be approximately 10 mW. Several recommendations for future space-based wave injection experiments are presented. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,GREENBELT,MD 20771. RUSSIAN ACAD SCI,SPACE RES INST,MOSCOW,RUSSIA. RP SONWALKAR, VS (reprint author), STANFORD UNIV,STAR LAB,STANFORD,CA 94305, USA. NR 25 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6173 EP 6186 DI 10.1029/93JA03310 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000043 ER PT J AU IYEMORI, T SUGIURA, M OKA, A MORITA, Y ISHII, M SLAVIN, JA BRACE, LH HOFFMAN, RA WINNINGHAM, JD AF IYEMORI, T SUGIURA, M OKA, A MORITA, Y ISHII, M SLAVIN, JA BRACE, LH HOFFMAN, RA WINNINGHAM, JD TI LOCALIZED INJECTION OF LARGE-AMPLITUDE PC-1 WAVES AND ELECTRON-TEMPERATURE ENHANCEMENT NEAR THE PLASMAPAUSE OBSERVED BY DE-2 IN THE UPPER IONOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ION-CYCLOTRON WAVES; HIGH-LATITUDES; ALFVEN-WAVE; F-REGION; FIELD; PROPAGATION; EXCITATION AB The relation between electron temperature enhancement and large amplitude Pc 1 wave injections in the upper ionosphere is investigated using the data obtained by the Dynamics Explorer 2 spacecraft. Results can be summarized as follows: (1) The region of the temperature enhancement coincides with that of the wave injection which is latitudinally very narrow (< 100 km) in comparison with the wavelength along the ambient magnetic field (several hundred kilometers). (2) The duration of the wave injection (or the temperature enhancement) seems to be less than a few hours even under quiet geomagnetic conditions, and/or the injection seems to be very localized, not only latitudinally, but also longitudinally. (3) The appearance and the magnitude of temperature enhancement depend on both the wave amplitude and the satellite altitude. (4) Two of the 22 events that were analyzed show a clear enhancement of low-energy electron flux (5-30 eV) at the wave injection, and the flux is field-aligned both downward and upward. The region of the temperature enhancement coincides with that of the downward electron flux. From these results, it is suggested that the temperature enhancement which accompanies large-amplitude waves with Pc 1 pulsation frequencies (0.2-5 Hz) is caused by the direct acceleration of thermal electrons at low altitudes by the parallel electric field (0.01-0.001 mV m-1) of the ion-cyclotron waves (kinetic Alfven waves) having an oblique wave normal. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. SW RES INST,SAN ANTONIO,TX 78284. TOKAI UNIV,INST RES & DEV,TOKYO 151,JAPAN. RP IYEMORI, T (reprint author), KYOTO UNIV,FAC SCI,KYOTO 606,JAPAN. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 27 TC 7 Z9 7 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6187 EP 6199 DI 10.1029/93JA02750 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000044 ER PT J AU WU, Q KILLEEN, TL SPENCER, NW AF WU, Q KILLEEN, TL SPENCER, NW TI DYNAMICS EXPLORER-2 OBSERVATIONS OF EQUATORIAL THERMOSPHERIC WINDS AND TEMPERATURES - LOCAL TIME AND LONGITUDINAL DEPENDENCES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INCOHERENT-SCATTER DATA; REGION NEUTRAL WINDS; F-REGION; MASS-SPECTROMETER; MAGNETIC SUBSTORM; MERIDIONAL WINDS; ELECTRIC-FIELDS; SATELLITE DATA; LOW LATITUDES; GLOBAL-MODEL AB We have analyzed a large database of Dynamics Explorer 2 (DE 2) measurements of equatorial (< +/-9-degrees latitude) thermospheric neutral temperatures and horizontal wind components in the altitude range from 200 to 400 km for quiet and active geomagnetic conditions (Kp < 3 and Kp > 3, respectively). Local time variations and longitudinal dependences on the duskside, dayside, and nightside have been separately examined. The dayside hourly averaged neutral zonal winds are relatively insensitive to variations in geomagnetic activity and appear to show an inverse dependence (lower zonal wind speed for higher Kp) in the midnight-dawn local time sector. The duskside neutral temperatures show a region of enhancement (by approximately 60 K) over the South Atlantic magnetic anomaly. The quiet time zonal winds are weaker than the corresponding active time zonal winds on the dayside near the South Atlantic magnetic anomaly. Enhanced ionization in the region, which increases the ion drag on the neutral gas, is suggested as the causal mechanism for these effects. The DE 2 averaged measurements have also been compared with MSIS-86/HWM90 and VSH models. The data and models are in good general agreement, though, the MSIS-86/HWM90 model predicts stronger dayside zonal winds than are observed under active conditions and the VSH model appears to underestimate the magnitude of the dayside zonal winds for both high and low Kp cases. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV RES FDN,GREENBELT,MD 20771. RP WU, Q (reprint author), UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES LAB,2455 HAYWARD,ANN ARBOR,MI 48109, USA. NR 47 TC 24 Z9 25 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6277 EP 6288 DI 10.1029/93JA02521 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000051 ER PT J AU FENNELLY, JA TORR, DG RICHARDS, PG TORR, MR AF FENNELLY, JA TORR, DG RICHARDS, PG TORR, MR TI SIMULTANEOUS RETRIEVAL OF THE SOLAR EUV FLUX AND NEUTRAL THERMOSPHERIC O, O2, N2, AND TEMPERATURE FROM TWILIGHT AIRGLOW SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID IONIZATION FREQUENCIES; MODEL; PHOTOELECTRON; CYCLE-21; DENSITY; RATES AB We present a method to retrieve neutral thermospheric composition and the solar EUV flux from ground-based twilight optical measurements of the O+(2P) 7320 angstrom and O(1D) 6300 angstrom airglow emissions. The parameters retrieved are the neutral temperature, the O, O2, N2 density profiles, and a scaling factor for the solar EUV flux spectrum. The temperature, solar EUV flux scaling factor, and atomic oxygen density are first retrieved from the 7320-angstrom emission, which are then used with the 6300-angstrom emission to retrieve the O2 and N2 densities. The retrieval techniques have been verified by computer simulations. We have shown that the retrieval technique is able to statistically retrieve values, between 200 and 400 km, within an average error of 3.1 +/- 0.6% for thermospheric temperature, 3.3 +/- 2.0% for atomic oxygen, 2.3 +/- 1.3% for molecular oxygen, and 2.4 +/- 1.3% for molecular nitrogen. The solar EUV flux scaling factor was found to have a retrieval error of 5.1 +/- 2.3%. All the above errors have a confidence level of 95%. The purpose of this paper is to prove the viability and usefulness of the retrieval technique by demonstrating the ability to retrieve known quantities under a realistic simulation of the measurement process, excluding systematic effects. C1 UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,HUNTSVILLE,AL 35899. UNIV ALABAMA,DEPT COMP SCI,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PAYLOADS PROJECT OFF,HUNTSVILLE,AL 35812. RP FENNELLY, JA (reprint author), UNIV ALABAMA,OPT AERON LAB,HUNTSVILLE,AL 35899, USA. NR 35 TC 7 Z9 7 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6483 EP 6490 DI 10.1029/93JA03479 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000066 ER PT J AU LU, G RICHMOND, AD EMERY, BA REIFF, PH DELABEAUJARDIERE, O RICH, FJ DENIG, WF KROEHL, HW LYONS, LR RUOHONIEMI, JM FRIISCHRISTENSEN, E OPGENOORTH, H PERSSON, MAL LEPPING, RP RODGER, AS HUGHES, T MCEWIN, A DENNIS, S MORRIS, R BURNS, G TOMLINSON, L AF LU, G RICHMOND, AD EMERY, BA REIFF, PH DELABEAUJARDIERE, O RICH, FJ DENIG, WF KROEHL, HW LYONS, LR RUOHONIEMI, JM FRIISCHRISTENSEN, E OPGENOORTH, H PERSSON, MAL LEPPING, RP RODGER, AS HUGHES, T MCEWIN, A DENNIS, S MORRIS, R BURNS, G TOMLINSON, L TI INTERHEMISPHERIC ASYMMETRY OF THE HIGH-LATITUDE IONOSPHERIC CONVECTION PATTERN SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; MAPPING ELECTRODYNAMIC FEATURES; INCOHERENT-SCATTER RADAR; DEPENDENT PLASMA-FLOW; ELECTRIC-FIELD; POLAR-CAP; BOUNDARY-LAYER; IMF-BY; PARTICLE-PRECIPITATION; LOCALIZED OBSERVATIONS AB The assimilative mapping of ionospheric electrodynamics technique has been used to derive the large-scale high-latitude ionospheric convection patterns simultaneously in both northern and southern hemispheres during the period of January 27-29, 1992. When the interplanetary magnetic field (IMF) B(z) component is negative, the convection patterns in the southern hemisphere are basically the mirror images of those in the northern hemisphere. The total cross-polar-cap potential drops in the two hemispheres are similar. When B(z) is positive and \B(y)\ > B(z), the convection configurations are mainly determined by B(y) and they may appear as normal ''two-cell'' patterns in both hemispheres much as one would expect under southward IMF conditions. However, there is a significant difference in the cross-polar-cap potential drop between the two hemispheres, with the potential drop in the southern (summer) hemisphere over 50% larger than that in the northern (winter) hemisphere. As the ratio of \B(y)\/B(z) decreases (less than one), the convection configuration in the two hemispheres may be significantly different, with reverse convection in the southern hemisphere and weak but disturbed convection in the northern hemisphere. By comparing the convection patterns with the corresponding spectrograms of precipitating particles, we interpret the convection patterns in terms of the concept of merging cells, lobe cells, and viscous cells. Estimates of the ''merging cell'' potential drops, that is, the potential ascribed to the opening of the dayside field lines, are usually comparable between the two hemispheres, as they should be. The ''lobe cell'' provides a potential between 8.5 and 26 kV and can differ greatly between hemispheres, as predicted. Lobe cells can be significant even for southward IMF, if \B(y)\ > \B(z)\. To estimate the potential drop of the ''viscous cells,'' we assume that the low-latitude boundary layer is on closed field lines. We find that this potential drop varies from case to case, with a typical value of 10 kV. If the source of these cells is truly a viscous interaction at the flank of the magnetopause, the process is likely spatially and temporally varying rather than steady state. C1 AUSTRALIA ANARCTIC DIV,KINGSTON,TAS,AUSTRALIA. SRI INT,MENLO PK,CA 94025. PHILLIPS LAB,BEDFORD,MA 01731. AUSTRALIAN GEOL SURVEY ORG,CANBERRA,AUSTRALIA. DANISH METEOROL INST,DK-2791 COPENHAGEN,DENMARK. NATL RES COUNCIL CANADA,HERZBERG INST ASTROPHYS,OTTAWA K1A 0R6,ONTARIO,CANADA. NOAA,NATL GEOPHYS DATA CTR,BOULDER,CO 80303. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. AEROSP CORP,LOS ANGELES,CA 90009. SWEDISH INST SPACE PHYS,S-75590 UPPSALA,SWEDEN. UNIV HOUSTON,DEPT SPACE PHYS & ASTRON,HOUSTON,TX 77251. BRITISH ANTARCTIC SURVEY,CAMBRIDGE CB3 0ET,ENGLAND. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. INST GEOL & NUCL SCI,CHRISTCHURCH 9,NEW ZEALAND. RP LU, G (reprint author), NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307, USA. RI Lu, Gang/A-6669-2011; Reiff, Patricia/D-2564-2014 OI Reiff, Patricia/0000-0002-8043-5682 NR 70 TC 88 Z9 90 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6491 EP 6510 DI 10.1029/93JA03441 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000067 ER PT J AU BARNES, A AF BARNES, A TI MOTION OF THE HELIOSPHERIC TERMINATION SHOCK .2. ENERGY-LOSS DUE TO ENERGETIC PARTICLE-ACCELERATION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DISTANCE AB We present a generalization of earlier analysis of the motion of the heliospheric termination shock in response to heliospheric disturbances (Barnes, 1993) (paper 1), to allow jump conditions that include an energy sink at the shock front. The motivation for this study is that acceleration of the anomalous cosmic ray component may in fact represent such a sink. We have idealized the situation by assuming an infinitely thin shock parameterized by a quantity lambda (0 less-than-or-equal-to lambda less-than-or-equal-to 1), defined as the fraction of solar wind energy that is lost due to acceleration of the energetic particle component. If the sink is strong (consuming, say, 50% or more of the incident solar wind energy), the model leads to the following principal conclusions: (1) the shocked plasma would be much denser and cooler than in the standard gasdynamic case, thereby leading to more favorable conditions for direct observation of the shocked plasma; (2) the equilibrium shock position would be slightly farther (<10%) from the Sun than in the standard model; (3) as in the gasdynamic case, the shock would normally be in motion, so that the instantaneous position of the termination shock is not determined by interstellar conditions but by the recent history of the wind that has passed through the termination shock; and (4) the response of the shock to upstream disturbances would be similar to the response in the gasdynamic case, but the speed of the new termination shock would be somewhat smaller (probably by a factor of 4 or less). We estimate that this speed is typically, approximately a few tens of kilometers per second corresponding to an inward or outward excursion of order of <1 to several AU, rather less than conventional estimates of several tens of AU. RP BARNES, A (reprint author), NASA,AMES RES CTR,THEORET STUDIES BRANCH,CODE 245-3,MOFFETT FIELD,CA 94035, USA. NR 20 TC 28 Z9 28 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6553 EP 6560 DI 10.1029/94JA00262 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000073 ER PT J AU GAZIS, PR BARNES, A MIHALOV, JD LAZARUS, AJ AF GAZIS, PR BARNES, A MIHALOV, JD LAZARUS, AJ TI SOLAR-WIND VELOCITY AND TEMPERATURE IN THE OUTER HELIOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PROTON TEMPERATURE; EVOLUTION; PLASMA; AU; PIONEER-10; SHOCKS AB At the end of 1992, the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were at heliocentric distances of 56.0, 37.3, and 39.0 AU and heliographic latitudes of 3.3-degrees-N, 17.4-degrees-N, and 8.6-degrees-S, respectively. Pioneer 11 and Voyager 2 are at similar celestial longitudes, while Pioneer 10 is on the opposite side of the Sun. All three spacecraft have working plasma analyzers, so intercomparison of data from these spacecraft provides important information about the global character of the solar wind in the outer heliosphere. The averaged solar wind speed continued to exhibit its well-known variation with solar cycle: Even at heliocentric distances greater than 50 AU, the average speed is highest during the declining phase of the solar cycle and lowest near solar minimum. There was a strong latitudinal gradient in solar wind speed between 3-degrees and 17-degrees-N during the last solar minimum, but this gradient has since disappeared. The solar wind temperature declined with increasing heliocentric distance out to a heliocentric distance of at least 20 AU; this decline appeared to continue at larger heliocentric distances, but temperatures in the outer heliosphere were surprisingly high. While Pioneer 10 and Voyager 2 observed comparable solar wind temperatures, the temperature at Pioneer 11 was significantly higher, which suggests the existence of a large-scale variation of temperature with heliographic longitude. There was also some suggestion that solar wind temperatures were higher near solar minimum. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. RP GAZIS, PR (reprint author), NASA,AMES RES CTR,SAN JOSE STATE UNIV FDN,MOFFETT FIELD,CA 94035, USA. NR 35 TC 51 Z9 51 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6561 EP 6573 DI 10.1029/93JA03144 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000074 ER PT J AU WINTERHALTER, D SMITH, EJ BURTON, ME MURPHY, N MCCOMAS, DJ AF WINTERHALTER, D SMITH, EJ BURTON, ME MURPHY, N MCCOMAS, DJ TI THE HELIOSPHERIC PLASMA SHEET SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; PLANETARY SECTOR BOUNDARIES; SOLAR-WIND; CORONAL STREAMERS; 1 AU; DYNAMICS; HELIUM; TAIL AB High-resolution magnetic field and plasma data gathered by ISEE 3/ICE during several sector boundary crossings are used to investigate the narrow heliospheric current sheet (almost-equal-to 3 x 10(3) km to 10(4) km thick), together with the heliospheric plasma sheet in which it is embedded. The heliospheric plasma sheet region is identified by a significantly enhanced plasma beta caused by density enhancements and diminished magnetic field strength and is about 20 to 30 times the thickness of the current sheet. The thickness of the heliospheric plasma sheet is found to increase exponentially with its average proton density. The heliospheric current sheet is often displaced to one edge or the other of the heliospheric plasma sheet. Further, the point of maximum plasma beta in the plasma sheet, where the magnetic field strength is at a broad local minimum, is not colocated with the heliospheric current sheet. Within the plasma sheet, changes in the magnetic pressure are balanced by corresponding changes in the plasma thermal pressure as expected for a convected solar wind feature. In addition, observations show small pressure differences between the regions upstream and downstream of the plasma sheet, which are interpreted as causing the plasma sheet to move across the spacecraft. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP WINTERHALTER, D (reprint author), JET PROP LAB,MS 169506,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 33 TC 166 Z9 170 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1994 VL 99 IS A4 BP 6667 EP 6680 DI 10.1029/93JA03481 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF580 UT WOS:A1994NF58000081 ER PT J AU ELDRIDGE, JI EBIHARA, BT AF ELDRIDGE, JI EBIHARA, BT TI FIBER PUSH-OUT TESTING APPARATUS FOR ELEVATED-TEMPERATURES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID INTERFACIAL SHEAR-STRENGTH; MATRIX COMPOSITES; MECHANICAL-PROPERTIES; SLIDING RESISTANCE; SILICON-CARBIDE; CERAMIC-MATRIX; STRESS; ROUGHNESS AB A newly developed apparatus has been designed for performing fiber push-out testing on continuous fiber-reinforced composites at elevated temperatures. This test measures the force at which a fiber resists being pushed by a flat-bottomed indenter moving at a constant speed. The applied load versus time curve characterizes the fiber debonding and sliding behavior. Extending measurements to elevated temperatures required incorporating sample/indenter heating in a nonoxidizing environment. With this new apparatus, fiber push-out tests have been performed up to 1100-degrees-C in a vacuum of 10(-6) Torr. A line-of-sight to the sample is maintained during the test which allows video monitoring of the push-out process. Results are shown for SCS-6 SiC fiber-reinforced Ti-24Al-11Nb (at. %) and Ti-15V-3Cr-3Sn-3Al (at. %) matrix composites. The results are discussed in terms of residual stresses, interfacial wear, matrix ductility, and changing modes of interfacial failure. The effect of temperature-dependent interfacial wear on the interfacial roughness contribution to frictional shear stresses during fiber sliding is examined. RP ELDRIDGE, JI (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 28 TC 33 Z9 33 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1994 VL 9 IS 4 BP 1035 EP 1042 DI 10.1557/JMR.1994.1035 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA NA985 UT WOS:A1994NA98500029 ER PT J AU UNGAR, AA AF UNGAR, AA TI THE ABSTRACT COMPLEX LORENTZ TRANSFORMATION GROUP WITH REAL METRIC .2. THE INVARIANCE GROUP OF THE FORM VERTICAL-BAR-T-VERTICAL-BAR(2)-PARALLEL-TO-X-PARALLEL-TO(2) SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID VELOCITY COMPOSITION PARADOX; THOMAS ROTATION; SPIN AB Let TX = C X V(infinity) be equipped with the Hermitian form Absolute value of t 2 - parellel-to x parallel-to 2, where t is-an-element-of C is a complex number and x is-an-element-of V(infinity) is a vector in an abstract complex inner product space V(infinity). The abstract complex Lorentz group (with real metric) is the invariance group of this form. A novel formalism to deal with the abstract real Lorentz transformation group has recently been developed by Ungar [Am. J. Phys. 59, 824-834 (1991); Am. J. Phys. 60, 815-828 (1992)], allowing one to solve in an abstract context previously poorly understood problems in one time and three space dimensions. Intrigued by the success of the abstract real Lorentz group formalism, resulting in the understanding of Thomas gyration in its abstract context, a formalism to deal with the abstract complex Lorentz group is proposed in this article. The extension from the real to the complex Lorentz group is not trivial. Complex Lorentz groups involve two interacting gyrations, a complex-time gyration and a complex-space gyration, as opposed to the real case which involves a single gyration, that is, a real-space gyration called Thomas gyration. The proposed formalism allows one to manipulate the seemingly involved abstract complex Lorentz group in a way analogous to the way one commonly manipulates Galilei transformation groups. Thus, for instance, equipped with the proposed formalism, one can readily (i) compose abstract complex Lorentz transformations, and (ii) determine those which link any two given events by manipulations analogous to Galilei group manipulations. When the abstract complex inner product space V(infinity) associated with the underlying abstract complex Minkowski space is realized by a finite-dimensional complex Hilbert space of dimension n, the abstract complex Lorentz group studied in this article reduces to the group U(1,n) or SU(1,n), depending on whether unitary or special unitary transformations are being considered. RP UNGAR, AA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 47 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD APR PY 1994 VL 35 IS 4 BP 1881 EP 1913 DI 10.1063/1.530576 PG 33 WC Physics, Mathematical SC Physics GA NE020 UT WOS:A1994NE02000031 ER PT J AU BLELLOCH, GE HARDWICK, JC SIPELSTEIN, J ZAGHA, M CHATTERJEE, S AF BLELLOCH, GE HARDWICK, JC SIPELSTEIN, J ZAGHA, M CHATTERJEE, S TI IMPLEMENTATION OF A PORTABLE NESTED DATA-PARALLEL LANGUAGE SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article ID COLLECTION-ORIENTED LANGUAGES; PROGRAMS AB This paper gives an overview of the implementation of NESL, a portable nested data-parallel language. This language and its implementation are the first to fully support nested data structures as well as nested data-parallel function calls. These features allow the concise description of parallel algorithms on irregular data, such as sparse matrices and graphs. In addition, they maintain the advantages of data-parallel languages: a simple programming model and portability. The current NESL implementation is based on an intermediate language called VCODE and a library of vector routines called CVL. It runs on the Connection Machines CM-2 and CM-5, the Cray Y-MP C90, and serial workstations. We compare initial benchmark results of NESL, with those of machine-specific code on these machines for three algorithms: least-squares line-fitting, median finding, and a sparse-matrix vector product. These results show that NESL's performance is competitive with that of machine-specific codes for regular dense data, and is often superior for irregular data. (C) 1994 Academic Press, Inc. C1 NASA,AMES RES CTR,RIACS,MOFFETT FIELD,CA 94035. RP BLELLOCH, GE (reprint author), CARNEGIE MELLON UNIV,SCH COMP SCI,PITTSBURGH,PA 15213, USA. NR 51 TC 77 Z9 77 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 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD APR PY 1994 VL 21 IS 1 BP 4 EP 14 DI 10.1006/jpdc.1994.1038 PG 11 WC Computer Science, Theory & Methods SC Computer Science GA NH279 UT WOS:A1994NH27900002 ER PT J AU CHOI, SR SALEM, JA AF CHOI, SR SALEM, JA TI CRACK-GROWTH RESISTANCE OF IN-SITU-TOUGHENED SILICON-NITRIDE SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID MEASURING FRACTURE-TOUGHNESS; R-CURVE BEHAVIOR; INDENTATION TECHNIQUES; STRENGTH; STABILITY; SPECIMENS; CERAMICS; SI3N4 AB The fracture toughness of a commercial, hot-pressed, in situ-toughened silicon nitride with an elongated grain structure is determined by four different testing methods. The fracture toughness is found to be 5.76 +/- 0.27, 8.48 +/- 0.50, 10.16 +/- 0.66, and 10.68 +/- 0.39 MPa.m1/2, respectively, by indentation crack size measurement, indentation strength, single-edge-precracked-beam, and chevron-notched-beam methods. The discrepancy in fracture toughness between the testing methods is related to R-curve behavior, as measured using the indentation strength technique. These results indicate that there is no unique fracture toughness value and that a fracture toughness testing method with appropriate qualifiers is needed for rising R-curve materials. Therefore, care should be taken in interpreting and utilizing fracture toughness values evaluated from different testing methods if a material exhibits a rising R-curve. Complete characterization of the R-curve may be a prerequisite. C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44115. RP CHOI, SR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 20 TC 40 Z9 40 U1 0 U2 4 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 APR PY 1994 VL 77 IS 4 BP 1042 EP 1046 DI 10.1111/j.1151-2916.1994.tb07265.x PG 5 WC Materials Science, Ceramics SC Materials Science GA NG916 UT WOS:A1994NG91600025 ER PT J AU STRIEPE, SA SIMONSEN, LC NEALY, JE AF STRIEPE, SA SIMONSEN, LC NEALY, JE TI RADIATION EXPOSURE PREDICTIONS FOR LONG-DURATION-STAY MARS MISSIONS SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB In this study, the ionizing radiation environment is estimated, using the Mission Radiation Calculation (MIRACAL) program, for several long-duration-stay Mars missions proposed for early in the 21(st) century. Both minimum energy and fast transfer missions are evaluated and their 30-day maximum, annual maximum, and total slab skin and blood-forming organ (BFO) doses are compared. When large flares were included while the astronauts were on the surface, the delivered dose did not significantly contribute to the total dose (less than 4 cSv BFO dose, or 8 percent of the guideline annual limit, for the most energetic event simulated) due to the substantial protection provided by the Martian atmosphere. However, dose delivered by large flares during transit is dependent on vehicle shielding and distance from the Sun. All of the fast transfer missions studied had lower total and annual maximum doses than the corresponding minimum energy transfer missions (on average, 30 percent less for missions having no large flares and the shielding thicknesses evaluated in this study). For all the missions studied, having the astronauts spend one-third of their day during transit in a 10 g/cm(2) storm shelter resulted in an approximate 10 percent reduction in the total mission dose. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665. RP STRIEPE, SA (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST & CONCEPTS,HAMPTON,VA 23665, USA. NR 18 TC 3 Z9 3 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 APR-JUN PY 1994 VL 42 IS 2 BP 131 EP 142 PG 12 WC Engineering, Aerospace SC Engineering GA PG181 UT WOS:A1994PG18100001 ER PT J AU MARSHALL, JA LUTHCKE, SB AF MARSHALL, JA LUTHCKE, SB TI RADIATIVE FORCE MODEL PERFORMANCE FOR TOPEX/POSEIDON PRECISION ORBIT DETERMINATION SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB The TOPEX/Poseidon spacecraft was launched on August 10, 1992 to study the Earth's oceans. To achieve maximum benefit from the altimetric data collected, mission requirements dictate that TOPEX/Poseidon's orbit must be computed at an unprecedented level of accuracy. In order to satisfy these requirements, a nonconservative force model which accounts for the satellites's complex geometry, attitude, and surface properties has been developed. This ''box-wing'' representation treats the spacecraft as the combination of flat plates arranged in the shape of a box and a connected solar array. The nonconservative forces acting on each of the eight surfaces are computed independently, yielding vector accelerations which are summed to compute the aggregate effect on the satellite center-of-mass. Note that for the drag force, only the component parallel to the velocity vector is considered in this process. Parameters associated with each flat plate were derived from a finite element analysis of the spacecraft. Certain parameters can be inferred from tracking data and have been adjusted to obtain a better representation of the satellite acceleration history. Changes in the nominal mission profile and the presence of an ''anomalistic'' force have complicated this tuning process. Model performance, parameter sensitivities, and the ''anomalistic'' force will be discussed. C1 HUGHES STX CORP,LANHAM,MD. RP MARSHALL, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,GREENBELT,MD 20771, USA. RI Luthcke, Scott/D-6283-2012 NR 21 TC 15 Z9 15 U1 1 U2 2 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 1994 VL 42 IS 2 BP 229 EP 246 PG 18 WC Engineering, Aerospace SC Engineering GA PG181 UT WOS:A1994PG18100007 ER PT J AU MISHCHENKO, MI AF MISHCHENKO, MI TI TRANSFER OF POLARIZED INFRARED RADIATION IN OPTICALLY ANISOTROPIC MEDIA - APPLICATION TO HORIZONTALLY ORIENTED ICE CRYSTALS - COMMENT SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Note ID NONSPHERICAL PARTICLES; MULTIPLE-SCATTERING; HYDROMETEORS; PROPAGATION AB The calculations of multiple scattering of polarized infrared radiation by horizontally oriented ice crystals in a paper by Takano and Liou [J. Opt. Soc. Am. A 10, 1243 (1993)] are based on a vector radiative transfer equation that is not rigorous but rather should be considered approximate. Specifically, Takano and Liou use the scalar extinction coefficient instead of the 4 X 4 extinction matrix. Therefore additional computations based on the rigorous radiative transfer equation are necessary for ascertaining the accuracy of Takano and Liou's radiative transfer calculations. Also, contrary to the statement of Takano and Liou, the reciprocity relation for the phase matrix holds for any anisotropic scattering media, including horizontally oriented ice crystals. C1 HUGHES STX CORP,NEW YORK,NY 10025. RP MISHCHENKO, MI (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Mishchenko, Michael/D-4426-2012 NR 16 TC 5 Z9 5 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD APR PY 1994 VL 11 IS 4 BP 1376 EP 1377 DI 10.1364/JOSAA.11.001376 PG 2 WC Optics SC Optics GA NE243 UT WOS:A1994NE24300021 ER PT J AU CWIK, T VANDEGEIJN, R PATTERSON, J AF CWIK, T VANDEGEIJN, R PATTERSON, J TI APPLICATION OF MASSIVELY-PARALLEL COMPUTATION TO INTEGRAL-EQUATION MODELS OF ELECTROMAGNETIC SCATTERING SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID RADIATION AB Integral equation methods are widely used in the analysis and the design of electromagnetic systems. Traditionally, the limiting parts of the simulation have been the memory required for storing the dense matrix and the computational time required for solving the matrix equation. We report on the extension of integral equation solutions to new wavelength regimes and on completion of the solution in an amount of time that is practical for engineering applications. The numerical solution of the integral equation is computed on scalable, distributed-memory parallel computers. Essential to the numerical solution was the development of a complex-valued, highly optimized, dense-matrix equation solution algorithm for scalable machines. A portion of the research outlined is the development of this production-level library routine for the solution of linear equations on parallel computers. A convenient interface, useful for integral equation solutions, among others, was specifically developed in this study. This algorithm has the conveniences offered by the sequential libraries, can be easily ported between parallel platforms, and has been placed in the public domain. C1 UNIV TEXAS,DEPT COMP SCI,AUSTIN,TX 78712. RP CWIK, T (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 19 TC 13 Z9 13 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD APR PY 1994 VL 11 IS 4 BP 1538 EP 1545 DI 10.1364/JOSAA.11.001538 PG 8 WC Optics SC Optics GA NE243 UT WOS:A1994NE24300037 ER PT J AU SPUCKLER, CM SIEGEL, R AF SPUCKLER, CM SIEGEL, R TI REFRACTIVE-INDEX AND SCATTERING EFFECTS ON RADIATION IN A SEMITRANSPARENT LAMINATED LAYER SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID HEAT-TRANSFER AB Heat transfer characteristics are analyzed for a laminated layer of two semitransparent scattering materials with refractive indices larger than one. Each side of the composite is heated by radiation and convection. Energy is transferred internally by conduction, emission, absorption, and isotropic scattering. The external surfaces of the composite and its internal interface are diffuse, which is intended to model composite ceramics in high-temperature applications. The two sublayers can have differing refractive indices greater than one. This causes internal reflection of some energy within the layers. Coupled with scattering, this has a substantial effect on the temperature distribution. Results are given for various optical thicknesses and refractive indices of the sublayers, and for scattering albedos up to one. Comparisons of numerical solutions are made with limiting cases based on the pure scattering, radiative diffusion, transparent, and opaque limits in the individual layers. The limiting solutions are very useful because they are convenient to evaluate and provide accurate results for many cases of interest. RP SPUCKLER, CM (reprint author), NASA, LEWIS RES CTR, DIV INTERNAL FLUID MECH, HEAT TRANSFER BRANCH, CLEVELAND, OH 44135 USA. NR 19 TC 26 Z9 26 U1 0 U2 11 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 EI 1533-6808 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 1994 VL 8 IS 2 BP 193 EP 201 DI 10.2514/3.523 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA NG696 UT WOS:A1994NG69600001 ER PT J AU HARTUNG, LC MITCHELTREE, RA GNOFFO, PA AF HARTUNG, LC MITCHELTREE, RA GNOFFO, PA TI COUPLED RADIATION EFFECTS IN THERMOCHEMICAL NONEQUILIBRIUM SHOCK-CAPTURING FLOWFIELD CALCULATIONS SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID MODELS AB Lunar and Mars return conditions are examined using the Langley aerothermodynamic upwind relaxation algorithm flowfield code and the Langley optimized radiative nonequilibrium radiation code to assess the effect of radiative coupling on axisymmetric thermochemical nonequilibrium flows. Coupling of the two codes is achieved iteratively. Special treatment required to couple radiation in a shock-capturing method is discussed. Results indicate that while coupling effects are generally the same as occur in equilibrium flows, under certain conditions radiation can modify the chemical kinetics of a nonequilibrium flow, and thus after relaxation processes. Coupling effects are round to be small for all cases considered, except for a 5-m-diam aerobrake returning from Mars at 13.6 km/s. RP HARTUNG, LC (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681, USA. NR 22 TC 7 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 1994 VL 8 IS 2 BP 244 EP 250 DI 10.2514/3.530 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA NG696 UT WOS:A1994NG69600008 ER PT J AU OLYNICK, DR TAYLOR, JC HASSAN, HA AF OLYNICK, DR TAYLOR, JC HASSAN, HA TI COMPARISONS BETWEEN MONTE-CARLO METHODS AND NAVIER-STOKES EQUATIONS FOR REENTRY FLOWS SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB A detailed comparison is made between Navier-Stokes and direct stimulation Monte Carlo calculations for flows near the continuum limit to assess the accuracy of the continuum equations in this regime. Meaningful comparisons require the use of similar physical models. This necessitates the inclusion of a separate rotational energy equation and use of slip boundary conditions. Inclusion of slip boundary conditions resulted in improved agreement between surface properties. Moreover, good agreement was obtained for the various temperatures in the nonequilibrium portion of the flowfield that does not contain the shock region. Departures are noted in the shock region and in regions where thermal diffusion effects are important. C1 N CAROLINA STATE UNIV,DEPT MECH & AEROSP ENGN,RALEIGH,NC 27695. RP OLYNICK, DR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 21 TC 6 Z9 6 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 APR-JUN PY 1994 VL 8 IS 2 BP 251 EP 258 DI 10.2514/3.531 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA NG696 UT WOS:A1994NG69600009 ER PT J AU RICHTER, R GOTTSCHLICH, JM AF RICHTER, R GOTTSCHLICH, JM TI THERMODYNAMIC ASPECTS OF HEAT-PIPE OPERATION SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB In this article the general operation and performance of heat pipes is being approached from fundamental thermodynamic considerations. This is in contrast to the classic heat pipe design analysis which equates an available ''capillary pressure'' with the two pressure drops associated with the circulation of the working fluid in the vapor and liquid phase and body forces where applicable, and erroneously attributing the circulation of the working fluid in a heat pipe to ''capillary pumping.'' This article shows that the working fluid circulates in a heat pipe as the result of a thermodynamic cycle in which thermal energy is converted to kinetic energy. The basic analysis which is presented, and which can be extended in future research, identifies the total internal temperature difference over which the heat pipe operates and the heat pipe operating temperature as the two key operating parameters in full agreement with all observed heat transfer phenomena. For given physical characteristics of a heat pipe, i.e., length, internal and external diameters, wick, artery or groove structure, the thermal transport performance below its operating limits is shown to be entirely a function of these two parameters as it is for any other heat conductor. The thermodynamic cycle clarifies the often substantial discrepancy between the predicted and the actually realized thermal power transfer capacity of a heat pipe. C1 WRIGHT LAB,WRIGHT PATTERSON AFB,OH 45433. RP RICHTER, R (reprint author), CALTECH,JET PROP LAB,4800 OAK DR,M-S 157-102,PASADENA,CA 91104, USA. NR 13 TC 12 Z9 14 U1 0 U2 3 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 APR-JUN PY 1994 VL 8 IS 2 BP 334 EP 340 DI 10.2514/3.543 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA NG696 UT WOS:A1994NG69600021 ER PT J AU LAIRD, P SAUL, R AF LAIRD, P SAUL, R TI DISCRETE SEQUENCE PREDICTION AND ITS APPLICATIONS SO MACHINE LEARNING LA English DT Article DE SEQUENCE EXTRAPOLATION; STATISTICAL LEARNING; TEXT COMPRESSION; SPEEDUP LEARNING; MEMORY MANAGEMENT AB Learning from experience to predict sequences of discrete symbols is a fundamental problem in machine learning with many applications. We present a simple and practical algorithm (TDAG) for discrete sequence prediction. Based on a text-compression method, the TDAG algorithm limits the growth of storage by retaining the most likely prediction contexts and discarding (forgetting) less likely ones. The storage/speed tradeoffs are parameterized so that the algorithm can be used in a variety of applications. Our experiments verify its performance on data compression tasks and show how it applies to two problems: dynamically optimizing Prolog programs for good average-case behavior and maintaining a cache for a database on mass storage. C1 NASA,AMES RES CTR,RECOM TECHNOL INC,MOFFETT FIELD,CA 94035. RP LAIRD, P (reprint author), NASA,AMES RES CTR,AI RES BRANCH,MOFFETT FIELD,CA 94035, USA. NR 28 TC 21 Z9 22 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0885-6125 J9 MACH LEARN JI Mach. Learn. PD APR PY 1994 VL 15 IS 1 BP 43 EP 68 DI 10.1007/BF01000408 PG 26 WC Computer Science, Artificial Intelligence SC Computer Science GA NP587 UT WOS:A1994NP58700003 ER PT J AU BOEHLERT, GW MUNDY, BC AF BOEHLERT, GW MUNDY, BC TI VERTICAL AND ONSHORE-OFFSHORE DISTRIBUTIONAL PATTERNS OF TUNA LARVAE IN RELATION TO PHYSICAL HABITAT FEATURES SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE SCOMBRIDAE; LARVAL ECOLOGY; SPAWNING; ISLANDS; HAWAII ID BLUEFIN THUNNUS-MACCOYII; SEA-SURFACE TEMPERATURES; SOUTHERN BLUEFIN; INDIAN-OCEAN; KATSUWONUS-PELAMIS; TROPICAL PACIFIC; HAWAIIAN-ISLANDS; YELLOWFIN TUNA; SKIPJACK TUNA; SCOMBRIDAE AB The seasonal and spatial distributions of larval scombrids in Waters off Oahu, Hawaii, were studied in September and December 1985 and April and June 1986 to determine vertical and onshore-offshore patterns. Horizontal distribution was resolved by sampling transects of 3 stations on the windward (east; 3.7, 9.3, and 27.8 km offshore) and leeward (west; 1.8, 9.3, and 27.8 km offshore) sides of the island. Vertical distribution was resolved by sampling with MOCNESS and Manta nets in 8 depth strata (0 to 80 m) at the 2 nearshore stations and 9 depth strata (0 to 200 m) at the 4 offshore stations. Scombrid larvae were abundant in all months except December. Collections in September and June were dominated by Thunnus spp.; about half were large enough to be identified to species and were predominantly T. albacares. Thunnus spp. generally were most abundant closest to shore on the leeward side of the island. Larval Thunnus were not taken at > 60 m, were most abundant in the upper 20 m, and were captured in the neuston at night but rarely in daytime. The other 2 dominant larval scombrids, Katsuwonus pelamis and Auxis spp., were most abundant in slightly deeper water. K. pelamis were most abundant at offshore stations, but Auxis spp. showed no clear onshore-offshore pattern. In April, Auxis spp. were most abundant and comprised over 99% of all larval scombrids. Diel vertical distribution patterns were not consistent between cruises or sides of the island for any species studied. No evidence was found for diel Migratory behavior. The physical structure of the water column, particularly temperature and salinity, altered the spatial and temporal distribution patterns of larvae on short time and space scales and also on the seasonal Scale. Seasonal patterns of spawning were likely dependent upon availability of appropriate thermal habitat. Larval Thunnus spp. and K. pelamis, in particular, were abundant only when temperatures were relatively warm. Auxis spp. larvae were found over a wider range of temperature than were the other genera. We suggest that the high concentrations of scombrid larvae, particularly Thunnus spp., near islands may be related to habitat characteristics that promote higher larval survival than in oceanic waters. C1 NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, HONOLULU LAB, HONOLULU, HI 96822 USA. UNIV HAWAII, JOINT INST MARINE & ATMOSPHER RES, HONOLULU, HI 96822 USA. NR 60 TC 54 Z9 55 U1 0 U2 8 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. PD APR PY 1994 VL 107 IS 1-2 BP 1 EP 13 DI 10.3354/meps107001 PG 13 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA NH216 UT WOS:A1994NH21600001 ER PT J AU VANPARADIJS, J CHARLES, PA HARLAFTIS, ET AREVALO, MJ BARUCH, JEF CALLANAN, PJ CASARES, J DHILLON, VS GIMENEZ, A GONZALEZ, R MARTINEZPAIS, IG JONES, DHP HASSALL, BJM HELLIER, C KIDGER, MR LAZARO, C MARSH, TR MASON, KO MUKAI, K NAYLOR, T REGLERO, V RUTTEN, RGM SMITH, RC AF VANPARADIJS, J CHARLES, PA HARLAFTIS, ET AREVALO, MJ BARUCH, JEF CALLANAN, PJ CASARES, J DHILLON, VS GIMENEZ, A GONZALEZ, R MARTINEZPAIS, IG JONES, DHP HASSALL, BJM HELLIER, C KIDGER, MR LAZARO, C MARSH, TR MASON, KO MUKAI, K NAYLOR, T REGLERO, V RUTTEN, RGM SMITH, RC TI A 60-NIGHT CAMPAIGN ON DWARF NOVAE .1. PHOTOMETRIC VARIABILITY OF SU UMA AND YZ CNC SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE BINARIES, ECLIPSING; STARS, INDIVIDUAL, YZ CNC; STARS, INDIVIDUAL, SU UMA; NOVAE, CATACLYSMIC VARIABLES ID HIGH-SPEED PHOTOMETRY; CATACLYSMIC VARIABLES; VW HYDRI; Z-CHA; ACCRETION DISK; WALRAVEN PHOTOMETRY; Z-CHAMAELEONTIS; URSAE-MAJORIS; OY-CARINAE; IP-PEGASI AB A 60-night campaign on SU UMa, YZ Cnc and some secondary targets was carried out during 1988 December and 1989 January at the Observatorio del Roque de Los Muchachos (the 1988 International Time Project). The aim was to study the behaviour of these dwarf novae through their outburst cycle. Here we present the overall light curves of the main targets, SU UMa and YZ Cnc, which show that the optical fluxes continue to decrease after the end of the outburst. For YZ Cnc we find that, during quiescence, orbital variability is present, which may be interpreted as modulation caused by the bright-spot region. Near the end of an outburst, a weak, sinusoidal variation is observed; we discuss the possibility that this arises either from the secondary star or the accretion disc. C1 DEPT PHYS, ASTROPHYS NUCL PHYS LAB, OXFORD OX1 3RH, ENGLAND. ROYAL GREENWICH OBSERV, E-38780 SANTA CRUZ PALMA, SPAIN. UNIV LA LAGUNA, INST ASTROFIS CANARIAS, E-38200 LA LAGUNA, SPAIN. UNIV BRADFORD, DEPT ELECT ENGN, BRADFORD BD7 1DP, W YORKSHIRE, ENGLAND. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. INST NACL TECN AEROSPATIAL, E-28080 MADRID, SPAIN. EUROPEAN SPACE AGCY, 14E OBSERV, E-28080 MADRID, SPAIN. ROYAL GREENWICH OBSERV, CAMBRIDGE CB3 0EZ, ENGLAND. UCL, MULLARD SPACE SCI LAB, DORKING RH5 6NT, SURREY, ENGLAND. NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. UNIV KEELE, DEPT PHYS, KEELE ST5 5BG, STAFFS, ENGLAND. UNIV VALENCIA, DEPT MATEMAT APLICADO & ASTRON, E-46100 BURJASSOT, SPAIN. UNIV SUSSEX, CTR ASTRON, DIV PHYS & ASTRON, BRIGHTON BN1 9QH, E SUSSEX, ENGLAND. RP VANPARADIJS, J (reprint author), UNIV AMSTERDAM, INST ASTRON ANTON PANNEKOEK, NIKHEF-H, KRUISLAAN 403, 1098 SJ AMSTERDAM, NETHERLANDS. RI Naylor, Tim /A-9465-2015 NR 53 TC 15 Z9 15 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1994 VL 267 IS 3 BP 465 EP 472 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ND757 UT WOS:A1994ND75700002 ER PT J AU FABIAN, AC CRAWFORD, CS EDGE, AC MUSHOTZKY, RF AF FABIAN, AC CRAWFORD, CS EDGE, AC MUSHOTZKY, RF TI COOLING FLOWS AND THE X-RAY LUMINOSITY TEMPERATURE RELATION FOR CLUSTERS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE GALAXIES, CLUSTERING; COOLING FLOWS; X-RAYS, GALAXIES ID FLUX-LIMITED SAMPLE; EXOSAT OBSERVATIONS; PERSEUS CLUSTER; RICH CLUSTERS; GALAXIES; EVOLUTION; DYNAMICS AB The luminosity-temperature relation for clusters has a wide dispersion which has been explained as being due to a range of gas density or mass. We show here that the offset of a cluster from the mean relation is proportional to the stren th of its cooling flow. We also confirm a similar effect on the metallicity-temperature relation. Since the cooling flow itself cannot produce such large effects, we propose that they are due to a more widespread difference between the intracluster media of cooling flow and non-cooling flow clusters. We suggest that the effects may be due to the inhomogeneity of the intracluster medium that is required in cooling flows to explain the distributed mass deposition. The effects have implications for the cluster temperature function and for the evolution of clusters. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP FABIAN, AC (reprint author), UNIV CAMBRIDGE,INST ASTRON,MADINGLEY RD,CAMBRIDGE CB3 0HA,ENGLAND. NR 15 TC 122 Z9 122 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1994 VL 267 IS 3 BP 779 EP 784 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ND757 UT WOS:A1994ND75700032 ER PT J AU GARSTANG, M MASSIE, HL HALVERSON, J GRECO, S SCALA, J AF GARSTANG, M MASSIE, HL HALVERSON, J GRECO, S SCALA, J TI AMAZON COASTAL SQUALL LINES .1. STRUCTURE AND KINEMATICS SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTIVE SYSTEMS; OZONE PRODUCTION; MESOSCALE; MODEL AB Mesoscale to synoptic-scale squall lines that form along the northeastern coast of South America as sea-breeze-induced instability lines and propagate through the Amazon Basin are investigated using data collected during the April-May 1987 Amazon Boundary Layer Experiment (ABLE 2B). These systems, termed ''Amazon coastal squall lines'' (ACSL), have been noted by others, but details of the structure and evolution of the ACSL are limited. The present paper uses Geostationary Operational Environmental Satellite, radar, upper-air rawinsonde, and surface Portable Automated Mesonet data to describe the structure, dynamics, and life cycle of the ACSL. Twelve ACSL were sampled during ABLE 2B, and three cases are discussed in detail. The ACSL are discontinuous lines of organized mesoscale cloud clusters that propagate across the central Amazon Basin at speeds of 50-60 km h-1. The ACSL undergo six possible life cycle stages: coastal genesis, intensification, maturity, weakening, reintensification, and dissipation. Analysis also indicates that mesoscale clusters within the ACSL are composed of three distinct cloud components: a prestorm region that often contains towering cumulus, leading edge convection (LEC), and multiple, precipitating cloud layers in the trailing stratiform region (TSR). Divergence and vertical velocity calculations indicate deep vertical ascent in the LEC and a region of midlevel convergence (almost-equal-to 500 mb) in the TSR. The latter midlevel convergence is associated with a weak updraft above 500 mb and an unsaturated downdraft below. Vertical motions in the TSR are an order of magnitude smaller than in the LEC. Substantial shear in the low-level inflow occurs in all three case studies and, as suggested by model simulations, may play an important role in the longevity (24-48 h) of the ACSL. Profiles of equivalent potential temperature theta(e) taken from the prestorm, leading edge convection and trailing stratiform regions demonstrate that the ACSL stabilize the troposphere in their wake and remove a tropospheric minimum of theta(e). It is hypothesized that the removal of this minimum is accomplished both by direct mixing via vertical motions in the LEC (''hot towers'') and also through detrainment in the multiple-layered TSR. Part I describes the structure and kinematics of the ACSL, while Part II deals with the heat and moisture transports of these systems. C1 NASA,GODDARD SPACE FLIGHT CTR,SEVERE STORMS BRANCH,GREENBELT,MD 20771. USAF,WEATHER SERV HEADQUARTERS,SCOTT AFB,IL 62225. RP GARSTANG, M (reprint author), UNIV VIRGINIA,DEPT ENVIRONM SCI,CLARK HALL,CHARLOTTESVILLE,VA 22903, USA. NR 44 TC 55 Z9 59 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 1994 VL 122 IS 4 BP 608 EP 622 DI 10.1175/1520-0493(1994)122<0608:ACSLPI>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NC624 UT WOS:A1994NC62400002 ER PT J AU GRECO, S SCALA, J HALVERSON, J MASSIE, HL TAO, WK GARSTANG, M AF GRECO, S SCALA, J HALVERSON, J MASSIE, HL TAO, WK GARSTANG, M TI AMAZON COASTAL SQUALL LINES .2. HEAT AND MOISTURE TRANSPORTS SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEMS; NORTHEAST BRAZIL; CLOUD CLUSTERS; BUDGETS; SIMULATION; CUMULUS AB The column response to propagating deep convection over the central Amazon Basin is investigate with rawinsonde data from the Amazon Boundary Layer Experiment (ABLE 2B). Heat and moisture budgets are calculated from a relatively small surface network (1000 km2) to determine the distribution of heating within the convective and stratiform regions of three Amazon coastal squall lines (ACSL) in varying degrees of maturity. Portable Automated Mesonet instrumentation, satellite imagery, and radar data are used to partition the large-scale system into distinct cloud and rainfall components. The dimensions of the surface network enable an evaluation of the collective effects of an ensemble of convective elements that are considered to be representative of the synoptic-scale system. Calculations of Q1 and Q2 from the ABLE 2B network follow the methods used by Johnson and Young and Gallus and Johnson. The computations are performed over intervals of 3-6 h using composite soundings derived from a network average. The distribution of heating and drying for the 1 May 1987 ACSL and its variation in time are shown to be similar to the results of other studies, particularly those of West African squall lines. Peak heating occurs between 500 and 550 mb, and peak drying is concentrated between 450 and 650 mb. A lack of separation between the peaks in the convective Q, and Q2 profiles indicates a coupling of Q1 and Q2 and suggests the presence of significant stratiform processes in the absence of pronounced eddy transports. The vertical eddy flux of total heat (F) is calculated by assuming the horizontal eddy flux term is small relative to the net vertical transports. Even though the horizontal transfer of heat and moisture may not be negligible in this study, the area encompassed by the surface network is large relative to the area occupied by active portions of convective clouds. From a network perspective, these cloud-scale fluxes are considered small relative to the vertical eddy flux of total heat. The distribution of vertical eddy flux compares favorably with a mesoscale calculation performed by Gallus and Johnson for a midlatitude squall line suggesting the assumptions regarding the net contribution of the horizontal fluxes may be reasonable. Convective transports of heat are equalled by transports occurring within the stratiform region of the system. The heat transported by a single ACSL when extrapolated to the ACSL as a whole represents a significant contribution to the global heat balance. C1 UNIV VIRGINIA,DEPT ENVIRONM SCI,CLARK HALL,CHARLOTTESVILLE,VA 22903. USAF,WEATHER SERV HEADQUARTERS,SCOTT AFB,IL 62225. SM SYST & RES CORP,WASHINGTON,DC. NASA,GODDARD SPACE FLIGHT CTR,SEVERE STORMS BRANCH,GREENBELT,MD 20771. NR 44 TC 19 Z9 21 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 1994 VL 122 IS 4 BP 623 EP 635 DI 10.1175/1520-0493(1994)122<0623:ACSLPI>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NC624 UT WOS:A1994NC62400003 ER PT J AU MATHER, J AF MATHER, J TI RIPPLES IN TIME SO NEW STATESMAN & SOCIETY LA English DT Article C1 NASA,GODDARD SPACE FLIGHT CTR,COBE TEAM,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU STATESMAN & NATION PUBL CO LTD PI LONDON PA FOUNDATION HOUSE 38 KINGSLAND ROAD, LONDON, ENGLAND E2 8DQ SN 0954-2361 J9 NEW STATESMAN SOC PD APR 1 PY 1994 VL 7 IS 296 BP 38 EP 39 PG 2 WC Social Issues; Social Sciences, Interdisciplinary SC Social Issues; Social Sciences - Other Topics GA NF803 UT WOS:A1994NF80300025 ER PT J AU LAMKIN, SL KHANDELWAL, GS SHINN, JL WILSON, JW AF LAMKIN, SL KHANDELWAL, GS SHINN, JL WILSON, JW TI SPACE PROTON TRANSPORT IN ONE-DIMENSION SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB An approximate evaluation procedure is derived for a second-order theory of coupled nucleon transport in one dimension. An analytical solution with a simplified interaction model is used to determine quadrature parameters to minimize truncation error. Effects of the improved method on transport solutions with the BRYNTRN data base are evaluated. Comparisons with Monte Carlo benchmarks are given. Using different shield materials, the computational procedure is used to study the physics of space protons. A transition effect occurs in tissue near the shield interface and is most important in shields of high atomic number. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP LAMKIN, SL (reprint author), OLD DOMINION UNIV,DEPT PHYS,NORFOLK,VA 23529, USA. NR 22 TC 3 Z9 3 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD APR PY 1994 VL 116 IS 4 BP 291 EP 299 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA NE261 UT WOS:A1994NE26100005 PM 11537897 ER PT J AU SOUTAR, C MONROE, SE KNOPP, J AF SOUTAR, C MONROE, SE KNOPP, J TI MEASUREMENT OF THE COMPLEX TRANSMITTANCE OF THE EPSON LIQUID-CRYSTAL TELEVISION SO OPTICAL ENGINEERING LA English DT Article DE LIQUID CRYSTAL TELEVISION; SPATIAL LIGHT MODULATORS; OPTICAL CORRELATORS ID SPATIAL LIGHT-MODULATOR; PHASE-ONLY MODULATION AB The complex transmittance of an Epson liquid crystal television (LCTV) is determined as a function of the video drive signal. Several different operating configurations of the LCTV are established, and their usefulness as operating modes for spatial light modulators in the input and filter planes of a hybrid correlator is discussed. A high-stability phase measurement scheme is developed to determine the operating curves, and this system is presented. This measurement scheme is designed so that a fully characterized LCTV could be assuredly moved into the optical correlator. This allows filters to be calculated for the correlator using the exact physical action of the modulators. The transient response of the LCTV to field-rate changes in the video signal is also presented. It is observed that the switching speed of the liquid crystal molecules is a fundamental limitation on the operating speed of these devices. C1 LOCKHEED ENGN & SCI CO, HOUSTON, TX 77058 USA. UNIV MISSOURI KANSAS CITY, DEPT ELECT & COMP ENGN, INDEPENDENCE, MO 64050 USA. RP SOUTAR, C (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, DIV TRACKING & COMMUN, HOUSTON, TX 77058 USA. NR 26 TC 57 Z9 60 U1 0 U2 1 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD APR PY 1994 VL 33 IS 4 BP 1061 EP 1068 DI 10.1117/12.163142 PG 8 WC Optics SC Optics GA NG450 UT WOS:A1994NG45000008 ER PT J AU ALBIN, S BRYANT, AL EGALON, CO ROGOWSKI, RS AF ALBIN, S BRYANT, AL EGALON, CO ROGOWSKI, RS TI INJECTION EFFICIENCY FROM A SIDE-EXCITED THIN-FILM FLUORESCENT CLADDING OF A CIRCULAR WAVE-GUIDE SO OPTICAL ENGINEERING LA English DT Article DE CIRCULAR OPTICAL FIBERS; FLUOROSENSORS; OPTICAL FIBER DISTRIBUTED SENSORS; OPTICAL FIBER CHEMICAL SENSORS; STEP INDEX PROFILE FIBERS ID FIBER AB Experiments were conducted to verify a theoretical model on the injection efficiency of sources in the cladding of an optical fiber. The theoretical results predicted an increase in the injection efficiency for higher differences in refractive indices between the core and cladding. The experimental apparatus used consisted of a glass rod 50 cm long, coated at one end with a thin film of a fluorescent substance. The fluorescent substance was excited with side illumination, perpendicular to the rod axis, using a 476-nm argon-ion laser. Part of the excited fluorescence was injected into the core and guided to a detector. The signal was measured for several different cladding refractive indices. The cladding consisted of sugar dissolved in water, and the refractive index was changed by varying the sugar concentration in the solution. The results indicate that the power injected into the rod, due to evanescent wave injection, increases with the difference in refractive index, which is in qualitative agreement with theory. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP ALBIN, S (reprint author), OLD DOMINION UNIV,DEPT ELECT & COMP ENGN,NORFOLK,VA 23529, USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 1994 VL 33 IS 4 BP 1172 EP 1175 DI 10.1117/12.163119 PG 4 WC Optics SC Optics GA NG450 UT WOS:A1994NG45000027 ER PT J AU DURANTE, M GROSSI, GF GIALANELLA, G PUGLIESE, M NAPPO, M YANG, TC AF DURANTE, M GROSSI, GF GIALANELLA, G PUGLIESE, M NAPPO, M YANG, TC TI THE RADIOSENSITIVITY OF A HUMAN MAMMARY EPITHELIAL-CELL LINE SO PHYSICA MEDICA LA English DT Proceedings Paper CT VI National Meeting of the Societe-Italiana-Per-le-Ricerche-Sulle-Radiazioni CY OCT 19-22, 1992 CL CAPRI, ITALY SP SOC ITALIANA RIC RADIOZ, INT ASSOC RADIAT RES ID REPAIR; TRANSFORMATION; RADIATION C1 UNIV NAPOLI FEDERICO 2,DIPARTIMENTO SCI FIS,I-80125 NAPLES,ITALY. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RI Durante, Marco/K-1315-2014 NR 11 TC 0 Z9 0 U1 0 U2 0 PU GIARDINI EDITORI S A LUGANO PI LUGANO PA PIAZZA MONTE CENERI 13, CH6901 LUGANO, SWITZERLAND SN 1120-1797 J9 PHYS MEDICA JI Phys. Medica PD APR PY 1994 VL 10 SU 1 BP 67 EP 69 PG 3 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA NE252 UT WOS:A1994NE25200028 ER PT J AU WEATHERFORD, CA TEMKIN, A AF WEATHERFORD, CA TEMKIN, A TI COMPLETION OF A HYBRID-THEORY CALCULATION OF THE PI(G) RESONANCE IN ELECTRON-N2 SCATTERING SO PHYSICAL REVIEW A LA English DT Article ID TARGET WAVE-FUNCTION; LOW-ENERGY; VIBRATIONAL-EXCITATION; MOLECULE-SCATTERING; CROSS-SECTIONS; N-2; INCLUSION; IMPACT; E-N2; N2 AB A calculation of e-N2 scattering in the vicinity of the 2.4-eV (PI(g)) resonance has been completed. The main element of the calculation is a 15-term vibrational close-coupling expansion, reduced to coupled two-dimensional partial differential equations (PDE's), and solved using the noniterative PDE technique. The potential consists of static, exchange, and polarization parts; each part has been (previously) derived in a manner appropriate to its importance in the scattering equation. Results for the absolute total cross section, both in magnitude and shape of the substructure in the resonance region (1.5 < k2 < 3 eV), are in excellent accord with experiment. Angular distributions are also calculated and found to vary significantly in shape for different energies in the immediate vicinity of the center of the resonance (2.05 < k2 < 2.15 eV), indicating the need for differential measurements at a finer grid in energy and therefore requiring even better energy resolution. A comparison with other calculations and a discussion of some theoretical aspects are also included. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP WEATHERFORD, CA (reprint author), FLORIDA A&M UNIV,DEPT PHYS,TALLAHASSEE,FL 32307, USA. NR 38 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 1994 VL 49 IS 4 BP 2580 EP 2586 DI 10.1103/PhysRevA.49.2580 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA NG485 UT WOS:A1994NG48500052 ER PT J AU TRIPATHI, RK TOWNSEND, LW AF TRIPATHI, RK TOWNSEND, LW TI SIMPLE PARAMETRIZATION OF FRAGMENT REDUCED WIDTHS IN HEAVY-ION COLLISIONS SO PHYSICAL REVIEW C LA English DT Note ID MOMENTUM DISTRIBUTIONS; PROJECTILES AB A systematic analysis of the observed reduced widths obtained in relativistic heavy ion fragmentation reactions is used to develop a phenomenological parametrization of these data. The parametrization is simple, accurate, and completely general in applicability. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP TRIPATHI, RK (reprint author), CHRISTOPHER NEWPORT UNIV,DEPT PHYS,NEWPORT NEWS,VA 23602, USA. NR 16 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1994 VL 49 IS 4 BP 2237 EP 2239 DI 10.1103/PhysRevC.49.2237 PG 3 WC Physics, Nuclear SC Physics GA NG677 UT WOS:A1994NG67700064 PM 9969457 ER PT J AU TRIPATHI, RK TOWNSEND, LW KHAN, F AF TRIPATHI, RK TOWNSEND, LW KHAN, F TI ROLE OF INTRINSIC WIDTH IN FRAGMENT MOMENTUM DISTRIBUTIONS IN HEAVY-ION COLLISIONS SO PHYSICAL REVIEW C LA English DT Note ID PROJECTILES AB It is demonstrated that the intrinsic widths incorporating correlations in conjunction with dynamical contributions give better agreement with experiments for collisions in the energy range of 200A MeV to 2A GeV than using only intrinsic widths without correlations. The sensitivity of the intrinsic width decreases with increasing projectile mass. A simple recipe for calculating intrinsic width with correlations is presented. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. OLD DOMINION UNIV,DEPT PHYS,NORFOLK,VA 23529. RP TRIPATHI, RK (reprint author), CHRISTOPHER NEWPORT UNIV,DEPT PHYS,NEWPORT NEWS,VA 23602, USA. NR 15 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD APR PY 1994 VL 49 IS 4 BP R1775 EP R1777 PG 3 WC Physics, Nuclear SC Physics GA NG677 UT WOS:A1994NG67700010 ER PT J AU KRISHER, TP AF KRISHER, TP TI DETECTING ISOTROPHY - TO C OR NOT TO C - REPLY SO PHYSICS TODAY LA English DT Letter ID SPECIAL RELATIVITY; CLOCK SYNCHRONIZATION; TESTS RP KRISHER, TP (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD APR PY 1994 VL 47 IS 4 BP 15 EP 15 PG 1 WC Physics, Multidisciplinary SC Physics GA NG477 UT WOS:A1994NG47700004 ER PT J AU WISNIEWSKI, WZ HARRIS, AW AF WISNIEWSKI, WZ HARRIS, AW TI THE COMPLEX LIGHTCURVE OF 1992-NA SO PLANETARY AND SPACE SCIENCE LA English DT Article AB Amor asteroid 1992 NA was monitored during three nights at a large phase angle of -65-degrees. The lightcurves obtained did not reveal a repeatable curve with two maxima and two minima. However, some features suggested a periodicity with three maxima and three minima. A satisfactory composite lightcurve of this form was obtained by means of an ''eyeball'' fit and by Fourier analysis. Individual and composite lightcurves are presented. The observed colors are consistent with the C class. C1 JET PROP LAB,PASADENA,CA 91109. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. NR 3 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 1994 VL 42 IS 4 BP 337 EP 339 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NZ133 UT WOS:A1994NZ13300013 ER PT J AU STAHLER, SW AF STAHLER, SW TI EARLY STELLAR EVOLUTION SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Review ID STAR FORMATION; PROTOSTELLAR DISKS; MOLECULAR CLOUD; PROTOSTARS; OBJECTS; CORES; TAURI AB Research into the formation and early evolution of stars is currently an area of great interest and activity. The theoretical and observational foundations for this development are reviewed in this paper. By now, the basic physics governing cloud collapse is well understood, as is the structure of the resulting protostars. However, the theory predicts protostellar luminosities that are greater than those of most infrared sources. Observationally, it is thought that protostars emit powerful winds that push away remnant cloud gas, but both the origin of these winds and the nature of their interaction with ambient gas are controversial. Finally, the theory of pre-main-sequence stars has been modified to incorporate more realistic initial conditions. This improvement helps to explain the distribution of such stars in the H-R diagram. Many important issues, such as the origin of binary stars and stellar clusters, remain as challenges for future research. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP STAHLER, SW (reprint author), UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. NR 47 TC 14 Z9 14 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 1994 VL 106 IS 698 BP 337 EP 343 DI 10.1086/133383 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NJ378 UT WOS:A1994NJ37800001 ER PT J AU DANKS, AC DENNEFELD, M AF DANKS, AC DENNEFELD, M TI AN ATLAS OF SOUTHERN MK STANDARDS FROM 5800 TO 10,200 A-ANGSTROM SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID CA-II; B-STARS; NA-I; SPECTRA; SPECTROPHOTOMETRY; ULTRAVIOLET; POPULATION; SEQUENCE; LIBRARY AB An atlas of stellar spectra covering the wavelength range from 5800 to 10,200 angstrom is presented of 126 southern MK standard stars, covering the luminosity classes I, III, and V. Some peculiar stars are included for comparison purposes. The spectra were obtained at a resolution of 4.3 angstrom per pixel using a Cassegrain-mounted Boller and Chivens spectrograph equipped with a Reticon detector. The quality and utility of the data are discussed and examples of the spectra are presented. The atlas is available in digital format through the NSSDC. C1 INST ASTROPHYS,F-75014 PARIS,FRANCE. RP DANKS, AC (reprint author), HUGHES STX CORP,GODDARD SPACE FLIGHT CTR,CODE 6830,GREENBELT,MD 20771, USA. NR 38 TC 49 Z9 50 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 1994 VL 106 IS 698 BP 382 EP 396 DI 10.1086/133390 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NJ378 UT WOS:A1994NJ37800008 ER PT J AU SIPPEL, SJ HAMILTON, SK MELACK, JM CHOUDHURY, BJ AF SIPPEL, SJ HAMILTON, SK MELACK, JM CHOUDHURY, BJ TI DETERMINATION OF INUNDATION AREA IN THE AMAZON RIVER FLOODPLAIN USING THE SMMR-37 GHZ POLARIZATION DIFFERENCE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BRAZIL AB The 37 GHz polarization difference observed by the Scanning Multichannel Microwave Radiometer (SMMR), which was operated on board the Nimbus-7 satellite, provides a sensitive indicator of surface water. These data ran provide information on seasonal inundation patterns large tropical wetlands such as the Amazon River floodplain. Although the SMMR data are of low resolution, we were able to estimate the area inundated within a group of pixels by using linear mixing models which incorporate the major end-members of the observed microwave signatures. The models were then used to estimate seasonal changes in inundation area over a 7-year period for a 34,550 km2 area along the Amazon River near Manaus. The seasonal changes in inundation area determined using mixing models correlate well with changes in river stage. C1 UNIV CALIF SANTA BARBARA,DEPT BIOL SCI,SANTA BARBARA,CA 93106. NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771. RI Hamilton, Stephen/N-2979-2014 OI Hamilton, Stephen/0000-0002-4702-9017 NR 16 TC 68 Z9 72 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR PY 1994 VL 48 IS 1 BP 70 EP 76 DI 10.1016/0034-4257(94)90115-5 PG 7 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA NN408 UT WOS:A1994NN40800007 ER PT J AU PRIVETTE, JL MYNENI, RB TUCKER, CJ EMERY, WJ AF PRIVETTE, JL MYNENI, RB TUCKER, CJ EMERY, WJ TI INVERTIBILITY OF A 1-D DISCRETE ORDINATES CANOPY REFLECTANCE MODEL SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID ESTIMATING AGRONOMIC VARIABLES; VEGETATION CANOPIES; SUITS MODEL; RADIATIVE-TRANSFER; PLANT CANOPY; SAIL MODEL; INVERSION; SCATTERING; PARAMETERS; EQUATION AB The invertibility of an accurate discrete ordinates canopy reflectance model is investigated through a series of experiments. Effects of different canopy types, noise levels, spectral ranges, and sampling geometries [including the NOAA Advanced Very High Resolution Radiometer (AVHRR) and the proposed Multi-angle Imaging SpectroRadiometer (MISR) satellite sampling schemes] are considered. Both error-free synthetic bidirectional reflectance data and empirical field reflectance data are utilized. Results suggest that the model can retrieve soil and canopy parameters with reasonable accuracy in most cases, and surface state parameters (absorbed radiation, spectral albedo and photosynthetic efficiency) with high accuracy in all cases. The efficiency of several commonly used optimization algorithms is also assessed, and a model sensitivity study is conducted. C1 NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771. RP PRIVETTE, JL (reprint author), UNIV COLORADO,DEPT AEROST ENGN SCI,CB 431,BOULDER,CO 80309, USA. RI Privette, Jeffrey/G-7807-2011; Myneni, Ranga/F-5129-2012; OI Privette, Jeffrey/0000-0001-8267-9894; Emery, William/0000-0002-7598-9082 NR 42 TC 58 Z9 61 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD APR PY 1994 VL 48 IS 1 BP 89 EP 105 DI 10.1016/0034-4257(94)90117-1 PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA NN408 UT WOS:A1994NN40800009 ER PT J AU LUHMANN, JG POLLACK, JB COLIN, L AF LUHMANN, JG POLLACK, JB COLIN, L TI THE PIONEER MISSION TO VENUS SO SCIENTIFIC AMERICAN LA English DT Article C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP LUHMANN, JG (reprint author), UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024, USA. NR 4 TC 2 Z9 2 U1 1 U2 1 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD APR PY 1994 VL 270 IS 4 BP 90 EP 97 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA NB548 UT WOS:A1994NB54800020 ER PT J AU NOEBE, RD GARG, A AF NOEBE, RD GARG, A TI CHARACTERIZATION OF NITROGEN-DOPED NIAL SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID HYDROSTATIC-PRESSURE; DUCTILITY RP NOEBE, RD (reprint author), NASA,LEWIS RES CTR,MS 49-3,CLEVELAND,OH 44135, USA. NR 20 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD APR 1 PY 1994 VL 30 IS 7 BP 815 EP 820 DI 10.1016/0956-716X(94)90396-4 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA MU741 UT WOS:A1994MU74100002 ER PT J AU GUYSE, CJ BUSCHER, DE ELLENBERGER, SR AF GUYSE, CJ BUSCHER, DE ELLENBERGER, SR TI REAL-TIME ENVIRONMENT AND VEHICLE DYNAMICS SIMULATIONS FOR SPACE STATION FREEDOM INTEGRATED TEST AND VERIFICATION ENVIRONMENT SO SIMULATION LA English DT Article DE REUSE; REAL-TIME SIMULATION; REAL-TIME TEST AND VERIFICATION; SIMULATION ENVIRONMENTS AB To reduce the costs associated with developing real-time simulations needed for the Space Station Freedom (SSF) Integration, Test and Verification Environment (ITVE), the National Aeronautics and Space Administration (NASA) investigated the possibility of integrating existing simulations with the ITVE. The purpose of this paper is to present a five-step generic approach for ''retro-fitting'' existing, NASA-owned simulations into the ITVE, as opposed to developing ITVE-specific simulations. The goals of the approach were (1) to minimize the modifications required to successfully integrate an existing simulation with the ITVE, and (2) to minimize the amount of knowledge and insight needed into the simulation to make the modifications. The five-step approach is generic in that it may be applied to any simulation that is being considered for integration with the ITVE. To test the approach, a NASA-MITRE team applied it to a subset of the Multiple Orbital Object Dynamics Simulation (MOODS) system. The results of that exercise are presented in this paper. C1 MITRE CORP,TECH STAFF,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,DIV FLIGHT DATA SYST,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,SPACE STN,DATA SYST BRANCH,HOUSTON,TX 77058. RP GUYSE, CJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV SYST,MAIL CODE EK74,HOUSTON,TX 77058, USA. NR 2 TC 1 Z9 2 U1 0 U2 0 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD APR PY 1994 VL 62 IS 4 BP 230 EP 239 DI 10.1177/003754979406200403 PG 10 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA NG821 UT WOS:A1994NG82100003 ER PT J AU HOMAIFAR, A QI, CX LAI, SH AF HOMAIFAR, A QI, CX LAI, SH TI CONSTRAINED OPTIMIZATION VIA GENETIC ALGORITHMS SO SIMULATION LA English DT Article DE GENETIC ALGORITHMS; CONSTRAINED OPTIMIZATION; NONLINEAR OPTIMIZATION AB This paper presents an application of genetic algorithms (GAs) to nonlinear constrained optimization. GAs are general purpose optimization algorithms which apply the rules of natural genetics to explore a given search space. When GAs are applied to nonlinear constrained problems, constraint handling becomes an important issue. The proposed search algorithm is realized by GAs which utilize a penalty function in the objective function to account for violation. This extension is based on systematic multi-stage assignments of weights in the penalty method as opposed to single-stage assignments in sequential unconstrained minimization. The experimental results are satisfactory and agree well with those of the gradient type methods. C1 MITSUBISHI SEMICOND AMER INC,DURHAM,NC 27704. N CAROLINA AGR & TECH STATE UNIV,NASA,CTR RES EXCELLENCE,DEPT MECH ENGN,CONTROLS & GUIDANCE GRP,GREENSBORO,NC 27411. RP HOMAIFAR, A (reprint author), N CAROLINA AGR & TECH STATE UNIV,NASA,CTR RES EXCELLENCE,DEPT ELECT ENGN,CONTROLS & GUIDANCE GRP,GREENSBORO,NC 27411, USA. NR 28 TC 317 Z9 363 U1 0 U2 20 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD APR PY 1994 VL 62 IS 4 BP 242 EP 253 DI 10.1177/003754979406200405 PG 12 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA NG821 UT WOS:A1994NG82100004 ER PT J AU MEINEL, AB AF MEINEL, AB TI SERAPHIN,BERNARD AND NOVEL SOLAR-ENERGY MATERIALS - IN THE BEGINNING SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article RP MEINEL, AB (reprint author), CALTECH,JET PROP LAB,1600 SHORELINE DR,SANTA BARBARA,CA 93109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD APR PY 1994 VL 32 IS 4 BP 327 EP 333 DI 10.1016/0927-0248(94)90096-5 PG 7 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA NM020 UT WOS:A1994NM02000003 ER PT J AU HATHAWAY, DH WILSON, RM REICHMANN, EJ AF HATHAWAY, DH WILSON, RM REICHMANN, EJ TI THE SHAPE OF THE SUNSPOT CYCLE SO SOLAR PHYSICS LA English DT Article ID NUMBER TIME-SERIES AB The temporal behavior of a sunspot cycle, as described by the International sunspot numbers, can be represented by a simple function with four parameters: starting time, amplitude, rise time, and asymmetry. Of these, the parameter that governs the asymmetry between the rise to maximum and the fall to minimum is found to vary little from cycle to cycle and can be fixed at a single value for all cycles. A close relationship is found between rise time and amplitude which allows for a representation of each cycle by a function containing only two parameters: the starting time and the amplitude. These parameters are determined for the previous 22 sunspot cycles and examined for any predictable behavior. A weak correlation is found between the amplitude of a cycle and the length of the previous cycle. This allows for an estimate of the amplitude accurate to within about 30% right at the stan of the cycle. As the cycle progresses, the amplitude can be better determined to within 20% at 30 months and to within 10% at 42 months into the cycle, thereby providing a good prediction both for the timing and size of sunspot maximum and for the behavior of the remaining 7-12 years of the cycle. RP HATHAWAY, DH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 21 TC 126 Z9 132 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD APR PY 1994 VL 151 IS 1 BP 177 EP 190 DI 10.1007/BF00654090 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NL584 UT WOS:A1994NL58400014 ER PT J AU DELLACORTE, C STEINETZ, B AF DELLACORTE, C STEINETZ, B TI TRIBOLOGICAL EVALUATION OF AN AL2O3-SIO2 CERAMIC FIBER CANDIDATE FOR HIGH-TEMPERATURE SLIDING SEALS SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 48th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 17-20, 1993 CL CALGARY, CANADA SP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS DE CERAMICS; SOLID LUBRICANTS; HIGH TEMPERATURES; FRICTION AND WEAR; SEALS ID WEAR AB A test program to determine the relative sliding durability of an alumina-silica candidate ceramic fiber for high temperature sliding seal applications is described. Pin-on-disk tests were used to evaluate the potential seal material by sliding a tow or bundle of the candidate ceramic fiber against a superalloy test disk. Friction was measured during the tests and fiber wear, indicated by the extent of fibers broken in the tow or bundle, was measured at the end of each test. Test variables studied included ambient temperatures from 25-degrees to 900-degrees-C, loads from 1.3 to 21.2 N, and sliding velocities from 0.025 to 0.25 m/sec. In addition, the effects of fiber diameter and elastic modulus on friction and wear were measured. Thin gold films deposited on the superalloy disk surface were evaluated in an effort to reduce friction and wear of the fibers. In most cases, wear increased with test temperature. Friction ranged from 0.36 at 500-degrees-C and low velocity (0.025 m/sec) to over 1.1 at 900-degrees-C and high velocity (0.25 m/sec). The gold films resulted in satisfactory lubrication of the fibers at 25-degrees-C. At elevated temperatures diffusion of substrate elements degraded the films. These results indicate that the alumina-silica (Al2O3-SiO2) fiber is a good candidate material system for high temperature sliding seal applications. More work is needed to reduce friction. RP DELLACORTE, C (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 13 TC 1 Z9 1 U1 1 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD APR PY 1994 VL 37 IS 2 BP 369 EP 377 DI 10.1080/10402009408983305 PG 9 WC Engineering, Mechanical SC Engineering GA NE950 UT WOS:A1994NE95000020 ER PT J AU MORRIS, CS GILL, SK AF MORRIS, CS GILL, SK TI VARIATION OF GREAT-LAKES WATER LEVELS DERIVED FROM GEOSAT ALTIMETRY SO WATER RESOURCES RESEARCH LA English DT Article ID SATELLITE ALTIMETRY AB A technique for using satellite radar altimetry data to estimate the temporal variation of the water level in moderate to large lakes and enclosed seas is described. Great Lakes data from the first 2 years of the U.S. Navy's Geosat Exact Repeat Mission (November 1986 to November 1988), for which there is an improved orbit, are used to demonstrate the technique. The Geosat results are compared to the lake level data collected by the Great Lakes Section, National Ocean Service, National Oceanic and Atmospheric Administration, and are found to reproduce the temporal variations of the five major lakes with root-mean-square error (rms) ranging from 9.4 to 13.8 cm and a combined average of 11.1 cm. Geosat data are also analyzed for Lake St. Clair, representing a moderate-sized lake, with a resulting rms of 17.0 cm. During this study period, the water level in the Great Lakes varied in a typical annual cycle of about 0.2 m (0.5 m for Lake Ontario) superimposed on a general decline of approximately 0.5 m. The altimeter data reproduced the general decline reasonably well for the lakes, but the annual cycle was obscured in some lakes due to systematic errors in the altimeter data. Current and future altimetry missions will have markedly improved accuracy which will permit many moderate (25 km diameter) or larger lakes or enclosed seas to be routinely monitored. C1 NOAA,NATL OCEAN SERV,SILVER SPRING,MD 20910. RP MORRIS, CS (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 18 TC 34 Z9 38 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD APR PY 1994 VL 30 IS 4 BP 1009 EP 1017 DI 10.1029/94WR00064 PG 9 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA NE300 UT WOS:A1994NE30000015 ER PT J AU QUIRK, JJ AF QUIRK, JJ TI A CONTRIBUTION TO THE GREAT RIEMANN SOLVER DEBATE SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE RIEMANN SOLVERS; SHOCK WAVES; NUMERICAL ARTIFACTS ID GODUNOV-TYPE METHODS; NUMERICAL-SIMULATION; EULER EQUATIONS; GAS-DYNAMICS; SCHEMES AB The aims of this paper are threefold: to increase the level of awareness within the shock-capturing community of the fact that many Godunov-type methods contain subtle flaws that can cause spurious solutions to be computed; to identify one mechanism that might thwart attempts to produce very-high-resolution simulations; and to proffer a simple strategy for overcoming the specific failings of individual Riemann solvers. RP QUIRK, JJ (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681, USA. NR 28 TC 321 Z9 332 U1 0 U2 13 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD MAR 30 PY 1994 VL 18 IS 6 BP 555 EP 574 DI 10.1002/fld.1650180603 PG 20 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA NE906 UT WOS:A1994NE90600002 ER PT J AU JAIN, RK LANDIS, GA WILT, DM FLOOD, DJ AF JAIN, RK LANDIS, GA WILT, DM FLOOD, DJ TI STRAINED IN0.40AL0.60AS WINDOW LAYERS FOR INDIUM-PHOSPHIDE SOLAR-CELLS SO APPLIED PHYSICS LETTERS LA English DT Article AB The efficiency of indium phosphide solar cells might be improved by a wide-band-gap window layer. In this work we calculate the performance of InP solar cells with a strained (pseudomorphic) In0.40Al0.60As window layer. Calculations show that the efficiencies of baseline and optimized p+n cells are increased to more than 22% and 24% (AM0, 25-degrees-C), respectively, for In0.40Al0.60As window layer of 10 nm thickness. Comparatively little improvement is found for n+p cells. RP JAIN, RK (reprint author), NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 15 TC 6 Z9 6 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 28 PY 1994 VL 64 IS 13 BP 1708 EP 1710 DI 10.1063/1.111990 PG 3 WC Physics, Applied SC Physics GA ND583 UT WOS:A1994ND58300038 ER PT J AU MCCORD, TB SODERBLOM, LA CARLSON, RW FANALE, FP LOPESGAUTIER, R OCAMPO, AC FORSYTHE, J CAMPBELL, B GRANAHAN, JC SMYTHE, WD WEISSMAN, PR BECKER, KJ EDWARDS, K KAMP, L LO, J MEHLMAN, R TORSON, J DANIELSON, GE MATSON, DL KIEFFER, HH JOHNSON, TV AF MCCORD, TB SODERBLOM, LA CARLSON, RW FANALE, FP LOPESGAUTIER, R OCAMPO, AC FORSYTHE, J CAMPBELL, B GRANAHAN, JC SMYTHE, WD WEISSMAN, PR BECKER, KJ EDWARDS, K KAMP, L LO, J MEHLMAN, R TORSON, J DANIELSON, GE MATSON, DL KIEFFER, HH JOHNSON, TV TI GALILEO INFRARED IMAGING SPECTROMETRY MEASUREMENTS AT THE MOON SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB Imaging spectrometer observations were made of the surface of the Moon during the December 1990 flyby of the Earth-Moon system by the Galileo spacecraft. This article documents this data set and presents analyses of some of the data. The near infrared mapping spectrometer (NIMS) investigation obtained 17 separate mosaics of the Moon in 408 spectral channels between about 0.7 and 5.2 mum. The instrument was originally designed to operate in orbit about Jupiter and therefore saturates at many spectral channels for most measurement situations at 1 AU. However, sufficient measurements were made of the Moon to verify the proper operation of the instrument and to demonstrate its capabilities. Analysis of these data show that the NIMS worked as expected and produced measurements consistent with previous ground-based telescopic studies. These are the first imaging spectrometer measurements of this type from space for the Moon, and they illustrate several major points concerning this type of observation and about the NIMS capabilities specifically. Of major importance are the difference between framing and scanning instruments and the effects of the spacecraft and the scan platform on the performance of such an experiment. The science return of subsequent NIMS and other investigation measurements will be significantly enhanced by the experience and results gained. C1 SETS TECHNOL INC,MILILANI,HI. US GEOL SURVEY,FLAGSTAFF,AZ 86001. JET PROP LAB,PASADENA,CA 91109. NATL AIR & SPACE MUSEUM,CTR EARTH & PLANETARY STUDIES,WASHINGTON,DC. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP MCCORD, TB (reprint author), UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,DIV PLANETARY GEOSCI,HONOLULU,HI 96822, USA. RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 5 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 25 PY 1994 VL 99 IS E3 BP 5587 EP 5600 DI 10.1029/93JE03434 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ND297 UT WOS:A1994ND29700001 ER PT J AU MELENDREZ, DE JOHNSON, JR LARSON, SM SINGER, RB AF MELENDREZ, DE JOHNSON, JR LARSON, SM SINGER, RB TI REMOTE-SENSING OF POTENTIAL LUNAR RESOURCES .2. HIGH-SPATIAL-RESOLUTION MAPPING OF SPECTRAL REFLECTANCE RATIOS AND IMPLICATIONS FOR NEARSIDE MARE TIO2 CONTENT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID TITANIUM; CLASSIFICATION; DEPOSITS; REGOLITH; GEOLOGY; SURFACE AB High spatial resolution maps illustrating variations in spectral reflectance 400/560 nm ratio values have been generated for the following mare regions: (1) the border between southern Mare Serenitatis and northern Mare Tranquillitatis (including the MS-2 standard area and Apollo 17 landing site), (2) central Mare Tranquillitatis, (3) Oceanus Procellarum near Seleucus, and (4) southern Oceanus Procellarum around Flamsteed. We have also obtained 320-1000 nm reflectance spectra of several sites relative to MS-2 to facilitate scaling of the images and provide additional information on surface composition. Inferred TiO2 abundances for these mare regions have been determined using an empirical calibration which relates the weight percent TiO2 in mature mare regolith to the observed 400/560 nm ratio. Mare areas with high TiO2 abundances are probably rich in ilmenite (FcTiO3) a potential lunar resource. The highest potential TiO2 concentrations we have identified in the nearside maria occur in central Mare Tranquillitatis' Inferred TiO2 contents for these areas are >9 wt % and are spatially consistent with the highest-TiO2 regions mapped previously at lower spatial resolution. We note that the morphology of surface units with high 400/560 nm ratio values increases in complexity at higher spatial resolutions. New telescopic spectra of landing sites successfully reproduce the Charette relation, although we find that the 400/560 nm value is strongly a function of the sample area size. The increased spectral contrast of the 400/730 nm ratio over the 400/560 nm ratio demonstrates the potential increased precision with which the 400/730 nm ratio might be used to estimate TiO2 abundances. Comparisons have been made with previously published geologic maps, Lunar Orbiter IV, and ground-based images, and some possible morphologic correlations have been found between our mapped 400/560 nm ratio values and volcanic landforms such as lava flows, marc domes, and collapse pits. C1 UNIV ARIZONA,NASA,SPACE ENGN UTILIZAT LOCAL PLANETARY RESOURCES RES CTR,TUCSON,AZ 85721. RP MELENDREZ, DE (reprint author), UNIV ARIZONA,PLANETARY IMAGE RES LAB,TUCSON,AZ 85721, USA. RI Johnson, Jeffrey/F-3972-2015 NR 50 TC 46 Z9 48 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 25 PY 1994 VL 99 IS E3 BP 5601 EP 5619 DI 10.1029/93JE03430 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ND297 UT WOS:A1994ND29700002 ER PT J AU MARDER, SR FERRY, JW AF MARDER, SR FERRY, JW TI NONLINEAR-OPTICAL POLYMERS - DISCOVERY TO MARKET IN 10 YEARS SO SCIENCE LA English DT Editorial Material ID 2ND HARMONIC-GENERATION; TEMPORAL STABILITY; ORGANIC-MOLECULES; SUSCEPTIBILITIES; POLYIMIDE C1 CALTECH,BECKMAN INST,CTR MOLEC MAT RESOURCE,PASADENA,CA 91125. RP MARDER, SR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 18 TC 165 Z9 167 U1 1 U2 19 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAR 25 PY 1994 VL 263 IS 5154 BP 1706 EP 1707 DI 10.1126/science.263.5154.1706 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA NC040 UT WOS:A1994NC04000022 PM 17795376 ER PT J AU BOURHILL, G BREDAS, JL CHENG, LT MARDER, SR MEYERS, F PERRY, JW TIEMANN, BG AF BOURHILL, G BREDAS, JL CHENG, LT MARDER, SR MEYERS, F PERRY, JW TIEMANN, BG TI EXPERIMENTAL DEMONSTRATION OF THE DEPENDENCE OF THE 1ST HYPERPOLARIZABILITY OF DONOR-ACCEPTOR-SUBSTITUTED POLYENES ON THE GROUND-STATE POLARIZATION AND BOND-LENGTH ALTERNATION SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID STILBENE DERIVATIVES; MOLECULES C1 DUPONT CO INC,CENT RES & DEV,WILMINGTON,DE 19880. JET PROP LAB,PASADENA,CA 91109. UNIV MONS HAINAUT,CTR RES MOLEC ELECTR & PHOTON,B-7000 MONS,BELGIUM. CALTECH,BECKMAN INST,CTR MOLEC MAT RESOURCE,PASADENA,CA 91125. RI Bredas, Jean-Luc/A-3431-2008; Perry, Joseph/B-7191-2011 OI Bredas, Jean-Luc/0000-0001-7278-4471; Perry, Joseph/0000-0003-1101-7337 NR 17 TC 259 Z9 259 U1 4 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAR 23 PY 1994 VL 116 IS 6 BP 2619 EP 2620 DI 10.1021/ja00085a052 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA NE026 UT WOS:A1994NE02600052 ER PT J AU MAUCHE, CW RAYMOND, JC BUCKLEY, DAH MOUCHET, M BONNELL, J SULLIVAN, DJ BONNETBIDAUD, JM BUNK, WH AF MAUCHE, CW RAYMOND, JC BUCKLEY, DAH MOUCHET, M BONNELL, J SULLIVAN, DJ BONNETBIDAUD, JM BUNK, WH TI OPTICAL, IUE, AND ROSAT OBSERVATIONS OF THE ECLIPSING NOVA-LIKE VARIABLE V347 PUPPIS (LB-1800) SO ASTROPHYSICAL JOURNAL LA English DT Article ID HIGH-VELOCITY WINDS; UX-URSAE-MAJORIS; X-RAY-EMISSION; T-TAURI STARS; DWARF NOVA; ACCRETION DISKS; CATACLYSMIC VARIABLES; SS-CYGNI; UV SPECTROSCOPY; Z CHAMAELEONTIS AB Using time-resolved optical spectroscopy and UBYRI and high-speed photometry obtained at Mount Stromlo Observatory, Mount John University Observatory, and the South African Astronomical Observatory; IUE ultraviolet spectroscopy; and ROSAT survey X-ray fluxes, we present a study of the accretion disk, hot spot, and emission line regions in the bright eclipsing nova-like variable V347 Pup (LB 1800). In the optical and UV, V347 Pup is a strong emission line source with a continuum spectrum which is remarkably red for a high-M cataclysmic variable. Consistent with its high inclination, we interpret the continuum spectrum as the superposition of the spectrum of the cool (T(eff) almost-equal-to 7000 K) outer edge and the hot (T(eff) almost-equal-to 100,000 K) inner regions of a self-eclipsed accretion disk. For the assumed parameters, the model matches the level and shape of the observed spectrum for an inclination of almost-equal-to 88-degrees and a distance of almost-equal-to 300 pc. The prominent hump in the optical and UV light curves just before eclipse manifests the presence of the hot spot where the accretion stream strikes the edge of the disk. The wavelength dependence of the amplitude of the hump is best modeled by a spot having an effective temperature of almost-equal-to 25,000 K and an area of almost-equal-to 3 x 10(18) cm2 if the spot radiates like a blackbody, or an effective temperature of almost-equal-to 14,000 K and an area of almost-equal-to 3 x 10(19) cm2 if it radiates with a stellar spectrum. In either case, the hot spot produces only one-tenth of the predicted luminosity for the assumed mass-transfer rate of 10(-8) M, yr-1. Either the hot spot is ''buried'' in the edge of the accretion disk, or a significant fraction of its luminosity is radiated away in lines. The difference in azimuth between the peak of the hump and the dynamically expected location of the hot spot suggests that the spot's emitting surface is rotated forward by almost-equal-to 36-degrees relative to the edge of the disk. Phase-resolved optical spectroscopy demonstrates that the optical continuum and emission line regions in V347 Pup have the same radial extent, that the bulk of the Hbeta emission line arises in the accretion disk but that it may also have a modest vertical extent, that the He II lambda4686 emission volume is both more sharply defined in the radial coordinate and less extended in the vertical direction, and that both the Hbeta and He II lambda4686 lines become narrower in eclipse, consistent with the eclipse of the inner, higher velocity, disk regions. In contrast, phase-resolved IUE spectroscopy demonstrates that the UV emission lines are only partially occulted in eclipse, indicating that they are formed in a region with dimensions comparable to the size of the secondary. Furthermore, the UV emission lines narrow only slightly in eclipse and have radial velocities which are delayed in phase relative to the optical emission lines by approximately 0.1 orbital cycles. The UV lines are modeled (poorly) by resonant scattering of accretion disk photons in a radially expanding wind emanating from the center of the disk. The required long acceleration scale and high wind mass-loss rate, combined with the prediction that the line widths should increase rather than decrease in eclipse, suggest that more complicated wind geometries may be necessary to explain the observed properties of the UV emission lines, including a possible rotational component near the disk plane and an additional emission component from the location of the hot spot. Finally, ROSAT survey observations indicate that V347 Pup is a weak and moderately soft X-ray source. Because of its high inclination, we argue that the X-rays do not come directly from the boundary layer but instead come from an extended emission volume. Possible sources of this emission include soft X-rays produced by shocks in the high-velocity wind and soft boundary layer X-rays which are scattered by the wind into the line of sight. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. S AFRICAN ASTRON OBSERV,CAPE TOWN 7935,SOUTH AFRICA. OBSERV PARIS,DAEC,SECT MEUDON,F-92195 MEUDON,FRANCE. UNIV PARIS 07,F-75251 PARIS 05,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GSFC,GRO SCI SUPPORT CTR,GREENBELT,MD 20771. VICTORIA UNIV WELLINGTON,DEPT PHYS,WELLINGTON,NEW ZEALAND. CENS,DAPNIA SAP,SERV ASTROPHYS,F-91191 GIF SUR YVETTE,FRANCE. MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. RP MAUCHE, CW (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,L-401,POB 808,LIVERMORE,CA 94550, USA. NR 77 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1994 VL 424 IS 1 BP 347 EP 369 DI 10.1086/173894 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA499 UT WOS:A1994NA49900028 ER PT J AU PORRI, A STALIO, R ALI, B POLIDAN, RS MOROSSI, C AF PORRI, A STALIO, R ALI, B POLIDAN, RS MOROSSI, C TI ANALYSIS OF VOYAGER SPECTRA OF THE BETA-CEPHEI STAR NU-ERIDANI SO ASTROPHYSICAL JOURNAL LA English DT Article DE CEPHEIDS; STARS, INDIVIDUAL (UPSILON ERIDANI); ULTRAVIOLET, SPECTRA ID BW VULPECULAE; INTERSTELLAR ABSORPTION; ULTRAVIOLET AB Voyager 500-1700 angstrom spectrophotometric observations of the beta Cephei star nu Eri are presented and discussed. The Voyager observations were obtained in 1981 and cover six pulsation cycles of the star. These data are supplemented with a set of nine IUE SWP high-resolution observations covering one, earlier epoch, pulsation cycle. Light curves are derived from the Voyager data at 1055 and 1425 angstrom. These light curves are found to be consistent in both shape and period with published optical curves. The 1055 angstrom light curve also exhibits a phenomenon not seen in the optical curves: a small but highly significant systematic increase in the flux of the maximum light phases while maintaining a constant minimum light level over the interval of observation. Substantially larger errors in the longer wavelength data preclude discussion of this phenomenon in the 1425 angstrom light curve. Examination of the far-UV continuum in v Eri during this period shows that the color temperature is lower for the brighter maxima. Analysis of the far-UV continuum at maximum and minimum light yields an effective temperature difference between these two phases of 2200 +/- 750 K. Spectroscopically, three prominent features are seen in the Voyager data: a feature at 985 angstrom mostly due to a blend of C III 977 angstrom, H I Lygamma 972 angstrom, and N III 990 angstrom; a feature at 1030 angstrom due to H I Lybeta 1026 angstrom and C II 1037 angstrom; and the Si IV resonance doublet near 1400 angstrom. A comparison of the 912-1700 angstrom spectral region in v Eri with a set of standard, i.e., nonpulsating stars, shows that nu Eri closely resembles the standard both in continuum shape and spectral line strengths with the possible exception of a slight flux excess between 912 and 975 angstrom. The equivalent width of the 985 angstrom feature is shown to vary in strength over the pulsation cycle in antiphase with the light curve and variations seen in the C iv 1548-1551 lines from the IUE data. This behavior of the 985 angstrom feature is most likely caused by variations in the strength of the Lygamma component of the blend. Comparisons are also made between nu Eri and the only other beta Cephei star studied in the far-UV, BW Vul, with the most notable differences between the two stars being the much larger DELTAT(eff) for BW Vul and the almost total absence of abnormalities in observed spectrum of nu Eri. C1 OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. ASTRON OBSERV TRIESTE,I-34131 TRIESTE,ITALY. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP PORRI, A (reprint author), CTR ADV RES SPACE OPT,AREA RIC,PADRICIANO 99,I-34012 TRIESTE,ITALY. NR 41 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1994 VL 424 IS 1 BP 401 EP 411 DI 10.1086/173898 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA499 UT WOS:A1994NA49900032 ER PT J AU HALTHORE, RN ALLEN, JE DECOLA, PL AF HALTHORE, RN ALLEN, JE DECOLA, PL TI A NON-LTE MODEL FOR THE JOVIAN METHANE INFRARED EMISSIONS AT HIGH-SPECTRAL-RESOLUTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SOLAR SYSTEM; MOLECULAR PROCESSES; PLANETS AND SATELLITES, INDIVIDUAL (JUPITER) ID MU-M; JUPITER; MIXTURES; AURORAE AB High resolution spectra of Jupiter in the 3.3 mum region have so far failed to reveal either the continuum or the line emissions that can be unambiguously attributed to the nu3 band of methane (Drossart et al. 1993; Kim et al. 1991). nu3 line intensities predicted with the help of two simple non-LTE models-a two-level model and a three-level model, using experimentally determined relaxation coefficients, are shown to be one to three orders of magnitude respectively below the 3sigma noise level of these observations. Predicted nu4 emission intensities are consistent with observed values. If the methane mixing ratio below the homopause is assumed as 2 x 10(-3), a value of about 300 K is derived as an upper limit to the temperature of the high stratosphere at microbar levels. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERRESTRIAL PHYS LAB,GREENBELT,MD 20771. RP HALTHORE, RN (reprint author), HUGHES STX CORP,4400 FORBES BLVD,LANHAM,MD 20706, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1994 VL 424 IS 1 BP L61 EP L64 DI 10.1086/187275 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA500 UT WOS:A1994NA50000016 ER PT J AU NEMIROFF, RJ WICKRAMASINGHE, WADT AF NEMIROFF, RJ WICKRAMASINGHE, WADT TI FINITE SOURCE SIZES AND THE INFORMATION-CONTENT OF MACHO-TYPE LENS SEARCH LIGHT CURVES SO ASTROPHYSICAL JOURNAL LA English DT Article DE DARK MATTER; GALAXY, HALO; GRAVITATIONAL LENSING; STARS, LOW-MASS, BROWN DWARFS ID GALACTIC HALO AB If the dark halo matter is primarily composed of MACHOs toward the lower end of the possible detection range (< 10(-3) M.) a fraction of the lens detection events should involve the lens crossing directly in front of the disk of the background star. Previously, Nemiroff has shown that each crossing would create an inflection point in the light curve of the MACHO event. Such inflection points would allow a measure of the time it took for the lens to cross the stellar disk. Given an independent estimate of the stellar radius by other methods, one could then obtain a more accurate estimate of the velocity of the lens. This velocity could then, in turn, be used to obtain a more accurate estimate of the mass range for the MACHO or disk star doing the lensing. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV PENN,PHILADELPHIA,PA 19104. RP NEMIROFF, RJ (reprint author), GEORGE MASON UNIV,CSI,FAIRFAX,VA 22030, USA. OI Nemiroff, Robert/0000-0002-4505-6599 NR 14 TC 89 Z9 89 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1994 VL 424 IS 1 BP L21 EP L23 DI 10.1086/187265 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA500 UT WOS:A1994NA50000006 ER PT J AU ULVESTAD, JS ANTONUCCI, RRJ AF ULVESTAD, JS ANTONUCCI, RRJ TI DO THE COMPACT RADIO-SOURCES IN NGC 253 AND M82 FADE OVER TIME SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC 253); GALAXIES, NUCLEI; GALAXIES, STARBURST; RADIO CONTINUUM, GALAXIES; SUPERNOVA REMNANTS ID SUPERNOVA; NGC-253 AB The nearby starburst galaxy NGC 253 has been observed at a third epoch at 6 cm, and a second epoch at 3.6 cm, using the highest resolution configuration of the VLA. Over a total time span of 4 yr between 1987 and 1991, no new compact radio sources have appeared. The flux density limit ranges from 3 mJy (3 times the power of Cas A) for most of the main body of the source to -0.3 mJy off the diffuse source surrounding the nucleus. Furthermore, there is no evidence for significant source fading over 4 yr, in contrast to the result reported by Kronberg & Sramek (1985) for M82. More recent data suggest that, except for the strongest source in that galaxy, the compact radio sources in M82 may not be fading after all. If this suggestion proves correct, supernova rates of 0.2-0.3 yr-1 in M82, estimated based on the assumed source fading, are incorrect. More accurate limits on source fading indicate that the current rate of production of radio supernovae in M82 is no greater than 0.1 yr-1, while that in NGC 253 is no greater than 0.25 yr-1. C1 UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. RP ULVESTAD, JS (reprint author), JET PROP LAB,MAIL STOP 301-125J,PASADENA,CA 91109, USA. NR 16 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 1994 VL 424 IS 1 BP L29 EP L32 DI 10.1086/187267 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA500 UT WOS:A1994NA50000008 ER PT J AU RATNAKUMAR, BV SURAMPUDI, S HALPERT, G AF RATNAKUMAR, BV SURAMPUDI, S HALPERT, G TI EFFECTS OF SULFUR ADDITIVE ON THE PERFORMANCE OF NA/NICL(2) CELLS SO JOURNAL OF POWER SOURCES LA English DT Article ID BATTERIES; CATHODES AB NiCl2 electrode in Na//beta''-alumina//NaAlCl4//NiCl2 high-temperature rechargeable cells undergoes a morphological change during charge/discharge cycling, which results in a rapid capacity decline and premature cell failure. Addition of sulfur was reported to have prevented this morphological change and improved the cycle life of the cells significantly. Our earlier, single electrode studies indicate that the sulfur additive also improves the kinetics of NiCl2. A detailed study on the effects of the sulfur additive on the performance of NiCl2 electrode is reported here. Different methods of NiCl2 electrode fabrication are examined to improve its charge efficiency. The sulfur content in the electrolyte is optimized based on the charge/discharge cycling and SEM micrographs. Other (non-sulfur) less corrosive additives, based on transition metals are examined for alleviating the morphological change during cycling. A combination of the transition metal additives and sulfur is expected to have a synergistic beneficial effect on the cycle life of NiCl2 electrode. RP RATNAKUMAR, BV (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 5 Z9 5 U1 1 U2 7 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD MAR 19 PY 1994 VL 48 IS 3 BP 349 EP 360 DI 10.1016/0378-7753(94)80031-6 PG 12 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA NF538 UT WOS:A1994NF53800008 ER PT J AU GRETEBECK, RJ SCHOELLER, DA DAVISSTREET, J SCHULZ, LO SOCKI, RA GIBSON, EK LANE, HW AF GRETEBECK, RJ SCHOELLER, DA DAVISSTREET, J SCHULZ, LO SOCKI, RA GIBSON, EK LANE, HW TI BACKGROUND CORRECTION TECHNIQUES FOR DOUBLY LABELED WATER WHEN DRINKING ISOTOPICALLY ENRICHED (SPACE-SHUTTLE) WATER SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,JSC,NUTR BIOCHEM LAB,HOUSTON,TX 77058. UNIV CHICAGO,CHICAGO,IL 60637. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 18 PY 1994 VL 8 IS 5 BP A725 EP A725 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND197 UT WOS:A1994ND19700812 ER PT J AU NAVIDI, M HARPER, J FUNG, P EVANS, J WOLINSKY, I ARNAUD, SB AF NAVIDI, M HARPER, J FUNG, P EVANS, J WOLINSKY, I ARNAUD, SB TI CALCIUM EXCRETION IN MATURE RATS FED HIGH DIETARY SALT DURING EXPOSURE TO A SPACE-FLIGHT MODEL SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV HOUSTON,HOUSTON,TX 77204. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 18 PY 1994 VL 8 IS 5 BP A705 EP A705 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND197 UT WOS:A1994ND19700697 ER PT J AU SMITH, SM SHIH, CY WIESMANN, H NYQUIST, LE NILLEN, JL LANE, HW AF SMITH, SM SHIH, CY WIESMANN, H NYQUIST, LE NILLEN, JL LANE, HW TI OPTIMIZATION OF ISOTOPE DOSES FOR CALCIUM-ABSORPTION AND KINETIC-STUDIES USING CA-43 SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,KRUG LIFE SCI,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 18 PY 1994 VL 8 IS 5 BP A708 EP A708 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND197 UT WOS:A1994ND19700715 ER PT J AU YELLE, JM CROUCH, JD SMITH, ML AF YELLE, JM CROUCH, JD SMITH, ML TI DIFFERENCES IN HYSTERESIS OF SYMPATHETIC AND VAGAL RESPONSES TO CAROTID BAROREFLEX STIMULATION SO FASEB JOURNAL LA English DT Meeting Abstract C1 CASE WESTERN RESERVE UNIV,DIV CARDIOL,CLEVELAND,OH 44106. NASA,JSC KRUG LIFE SCI,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 18 PY 1994 VL 8 IS 5 BP A849 EP A849 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND197 UT WOS:A1994ND19701529 ER PT J AU HAYNES, PL BALOGH, A DOUGHERTY, MK SOUTHWOOD, DJ FAZAKERLEY, A SMITH, EJ AF HAYNES, PL BALOGH, A DOUGHERTY, MK SOUTHWOOD, DJ FAZAKERLEY, A SMITH, EJ TI NULL FIELDS IN THE OUTER JOVIAN MAGNETOSPHERE - ULYSSES OBSERVATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID JUPITER; FLYBY AB This paper reports on a magnetic field phenomenon, hereafter referred to as null fields, which were discovered during the inbound pass of the recent flyby of Jupiter by the Ulysses spacecraft. These null fields which were observed in the outer dayside magnetosphere are characterised by brief but sharp decreases of the field magnitude to values less than 1 nT. The nulls are distinguished from the current sheet signatures characteristic of the middle magnetosphere by the fact that the field does not reverse across the event. A field configuration is suggested that accounts for the observed features of the events. C1 JET PROP LAB,PASADENA,CA 91109. RP HAYNES, PL (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON SW7 2BZ,ENGLAND. NR 6 TC 13 Z9 13 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 MAR 15 PY 1994 VL 21 IS 6 BP 405 EP 408 DI 10.1029/93GL01986 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NC446 UT WOS:A1994NC44600003 ER PT J AU BAKER, DN BLAKE, JB CALLIS, LB CUMMINGS, JR HOVESTADT, D KANEKAL, S KLECKER, B MEWALDT, RA ZWICKL, RD AF BAKER, DN BLAKE, JB CALLIS, LB CUMMINGS, JR HOVESTADT, D KANEKAL, S KLECKER, B MEWALDT, RA ZWICKL, RD TI RELATIVISTIC ELECTRON ACCELERATION AND DECAY TIME SCALES IN THE INNER AND OUTER RADIATION BELTS - SAMPEX SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PROTONS AB High-energy electrons have been measured systematically in a low-altitude (520 x 675 km), nearly polar (inclination = 82-degrees) orbit by sensitive instruments onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX). Count rate channels with electron energy thresholds ranging from 0.4 MeV to 3.5 MeV in three different instruments have been used to examine relativistic electron variations as a function of L-shell parameter and time. A long run of essentially continuous data (July 1992 - July 1993) shows substantial acceleration of energetic electrons throughout much of the magnetosphere on rapid time scales. This acceleration appears to be due to solar wind velocity enhancements and is surprisingly large in that the radiation belt ''slot'' region often is filled temporarily and electron fluxes are strongly enhanced even at very low L-values (L approximately 2). A superposed epoch analysis shows that electron fluxes rise rapidly for 2.5 less than or similar L less than or similar 5. These increases occur on a time scale of order 1-2 days and are most abrupt for L-values near 3. The temporal decay rate of the fluxes is dependent on energy and L-value and may be described by J = Ke-t/to with t(O) almost-equal-to 5-10 days. Thus, these results suggest that the Earth's magnetosphere is a cosmic electron accelerator of substantial strength and efficiency. C1 AEROSP CORP,EL SEGUNDO,CA 90245. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. CALTECH,PASADENA,CA 91125. MAX PLANCK INST EXTRATERR PHYS,GARCHING,GERMANY. NOAA,SPACE ENVIRONM LAB,BOULDER,CO 80303. RP BAKER, DN (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 690,GREENBELT,MD 20771, USA. NR 12 TC 157 Z9 162 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 1994 VL 21 IS 6 BP 409 EP 412 DI 10.1029/93GL03532 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NC446 UT WOS:A1994NC44600004 ER PT J AU YUE, GK VEIGA, RE WANG, PH AF YUE, GK VEIGA, RE WANG, PH TI SAGE-II OBSERVATIONS OF A PREVIOUSLY UNREPORTED STRATOSPHERIC VOLCANIC AEROSOL CLOUD IN THE NORTHERN POLAR SUMMER OF 1990 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EL CHICHON AB Analysis of aerosol extinction profiles obtained by the spaceborne SAGE II sensor reveals that there was an anomalous increase of aerosol extinction below 18.5 km at latitudes poleward of 50-degrees-N from July 28 to September 9, 1990. This widespread increase of aerosol extinction in the lower stratosphere was apparently due to a remote high-latitude volcanic eruption that has not been reported to date. The increase in stratospheric optical depth in the northern polar region was about 50% in August and had diminished by October 1990. This eruption caused an increase in stratospheric aerosol mass of about 0.33 x 10(5) tons, assuming the aerosol was composed of sulfuric acid and water. C1 SAIC,HAMPTON,VA 23666. SCI & TECHNOL CORP,HAMPTON,VA 23666. RP YUE, GK (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 13 TC 8 Z9 8 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 MAR 15 PY 1994 VL 21 IS 6 BP 429 EP 432 DI 10.1029/93GL03376 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NC446 UT WOS:A1994NC44600009 ER PT J AU AHUMADA, AJ TABERNERO, A AF AHUMADA, AJ TABERNERO, A TI ANTI-HEBBIAN LEARNING AND CORTICAL RECEPTIVE-FIELD CALIBRATION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FAC INFORMAT MADRID,MADRID,SPAIN. NR 3 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 1256 EP 1256 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58500010 ER PT J AU HECHT, H KAISER, MK AF HECHT, H KAISER, MK TI TIME-TO-PASSAGE JUDGMENTS IN NONCONSTANT OPTICAL-FLOW FIELDS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Hecht, Heiko/H-3106-2011 NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 1277 EP 1277 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58500112 ER PT J AU BORCHERT, M LAMBERT, JL SAKAMOTO, G AF BORCHERT, M LAMBERT, JL SAKAMOTO, G TI MORPHOMETRIC REFINEMENT OF RETINOTECTAL CONNECTIONS IN THE RAT SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 CHILDRENS HOSP LOS ANGELES,LOS ANGELES,CA. JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 1771 EP 1771 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58502390 ER PT J AU MCBEATH, MK SHAFFER, DM KAISER, MK AF MCBEATH, MK SHAFFER, DM KAISER, MK TI BASEBALL OUTFIELDERS CATCH FLY BALLS BY CANCELING OPTICAL CURVATURE NOT OPTICAL ACCELERATION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 KENT STATE UNIV,DEPT PSYCHOL,KENT,OH 44242. NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS RES,MOFFETT FIELD,CA 94035. RI Shaffer, Dennis/F-5300-2013 NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 1985 EP 1985 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58503378 ER PT J AU ANAND, S TOMKO, DL AF ANAND, S TOMKO, DL TI ADAPTIVE PLASTICITY IN THE SQUIRREL-MONKEY LINEAR VESTIBULOOCULAR REFLEX (LVOR) SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV CALIF SANTA CRUZ,DEPT PSYCHOL,SANTA CRUZ,CA 95064. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2036 EP 2036 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58503620 ER PT J AU TIANA, C LANHAM, J PAVEL, M AF TIANA, C LANHAM, J PAVEL, M TI INTEGRATION OF EDGE LOCATION INFORMATION ACROSS FREQUENCY SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,STERLING SOFTWARE,MOFFETT FIELD,CA 94035. OREGON GRAD INST,PORTLAND,OR 97291. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2064 EP 2064 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58503749 ER PT J AU THOMPSON, P STONE, LS SWASH, S STONE, R AF THOMPSON, P STONE, LS SWASH, S STONE, R TI CONTRAST DEPENDENCE OF SPEED PERCEPTION - EFFECTS OF BACKGROUND CONTRAST SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV YORK,DEPT PSYCHOL,YORK YO1 5DD,N YORKSHIRE,ENGLAND. NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 3 Z9 3 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2077 EP 2077 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58503801 ER PT J AU VERGHESE, P STONE, LS AF VERGHESE, P STONE, LS TI INTEGRATION OF SPEED INFORMATION ACROSS SPACE SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2077 EP 2077 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58503800 ER PT J AU BEUTTER, BR MULLIGAN, JB STONE, LS AF BEUTTER, BR MULLIGAN, JB STONE, LS TI THE BARBERPLAID ILLUSION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,DIV HUMAN FACTORS,MOFFETT FIELD,CA 94035. NR 1 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2157 EP 2157 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58504172 ER PT J AU MULLIGAN, JB BEUTTER, BR AF MULLIGAN, JB BEUTTER, BR TI ADDITIONAL TWISTS ON A CONTINUOUS BARBER-POLE ILLUSION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 1 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2158 EP 2158 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58504173 ER PT J AU PERRONE, JA AF PERRONE, JA TI SIMULATING THE SPEED AND DIRECTION TUNING OF MT-NEURONS USING SPATIOTEMPORAL TUNED V1-NEURON INPUTS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV WAIKATO,DEPT PSYCHOL,HAMILTON,NEW ZEALAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 1 TC 2 Z9 2 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2158 EP 2158 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58504175 ER PT J AU LARIMER, J MARTINEZURIEGAS, E LUBIN, J GILLE, J AF LARIMER, J MARTINEZURIEGAS, E LUBIN, J GILLE, J TI COLOR CONTRAST DISCRIMINATION THRESHOLDS AS PARAMETERS FOR A MODEL OF COLOR LCD IMAGE VISIBILITY SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SRI INT,MENLO PK,CA 94025. DAVID SARNOFF RES CTR,PRINCETON,NJ. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1994 VL 35 IS 4 BP 2167 EP 2167 PG 1 WC Ophthalmology SC Ophthalmology GA MZ585 UT WOS:A1994MZ58504211 ER PT J AU RYBICKI, GC ZORMAN, CA AF RYBICKI, GC ZORMAN, CA TI DEEP-LEVEL DEFECTS AND CARRIER REMOVAL DUE TO PROTON AND ALPHA-PARTICLE IRRADIATION OF INP SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID P-TYPE INP AB Deep level transient spectroscopy and capacitance voltage measurements of the defect introduction rates and carrier removal rates for 2 MeV proton and 2 MeV alpha particle irradiations in p-type InP have been performed. The carrier removal rate for 2 MeV protons was 6500 cm-1 and for 2 MeV alpha particles was 73 400 cm-1, or 12 times higher. The defect introduction rates for H4, the predominant radiation induced defect in p-type InP, were 229 per 2 MeV proton and 9000 per 2 MeV alpha particle, or 39 times higher for alpha irradiation. The very large rates of carrier removal and high defect introduction rates in the latter case may limit the usefulness of InP in a radiation environment containing high energy alpha particles. C1 CASE WESTERN RESERVE UNIV,DEPT PHYS,CLEVELAND,OH 44106. RP RYBICKI, GC (reprint author), NASA,LEWIS RES CTR,PHOTOVOLTAICS BRANCH,CLEVELAND,OH 44135, USA. OI Zorman, Christian/0000-0001-9773-9351 NR 9 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 15 PY 1994 VL 75 IS 6 BP 3187 EP 3189 DI 10.1063/1.356144 PG 3 WC Physics, Applied SC Physics GA NB413 UT WOS:A1994NB41300068 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI HOW LARGE IS THE EFFECT OF 1S CORRELATION ON THE D-E, OMEGA(E), AND R(E) OF N-2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLARIZATION BASIS FUNCTIONS; GAUSSIAN-BASIS SETS; ELECTRON CORRELATION; COUPLED CLUSTER; ATOMS; ENERGIES; 1ST-ROW; IMPACT; F2 AB The effect of N 1s correlation on the spectroscopic constants of N-2 is studied using the coupled-cluster singles and doubles approach with a perturbational estimate of the connected triples [CCSD(T)] and internally contracted multireference configuration interaction (ICMRCI) techniques. At the ICMRCI level, we obtain a Is effect of +1.35 kcal/mol on the dissociation energy. However, the effect is found to be smaller when size-extensive methods are used. The Is effects computed at the CCSD(T) and internally;contracted averaged coupled-pair:functional (ICACPF) levels are in excellent agreement. Our best estimate for the effect of Is correlation is +0.8 kcal/mol on D-e, +9 cm(-1) on omega(e), and -0.002 Angstrom on the bond length. Including our estimate for the effect of Is correlation, we obtain a D-e of 227.1 using a correlation-consistent polarized-valence sextuple zeta basis set at the ICMRCI+Q level (where the +Q indicates that the Davidson correction has been included). Basis set incompleteness, which is estimated to be 0.7+/-0.2 kcal/mol, is still the major source of error. The CCSD(T) ten-electron results are found to be in excellent agreement with those obtained at the ICACPF or ICMRCI+Q levels of theory. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 24 TC 65 Z9 66 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 15 PY 1994 VL 100 IS 6 BP 4329 EP 4335 DI 10.1063/1.466315 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA NA918 UT WOS:A1994NA91800030 ER PT J AU WANG, DW LIU, AK PENG, CY MEINDL, EA AF WANG, DW LIU, AK PENG, CY MEINDL, EA TI WAVE-CURRENT INTERACTION NEAR THE GULF-STREAM DURING THE SURFACE-WAVE DYNAMICS EXPERIMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID REFRACTION; AGULHAS; SPECTRA AB This paper presents a case study on the wave-current interaction near the local curvature of a Gulf Stream meander. The wave data were obtained from in situ measurements by a pitch-roll discus buoy during the Surface Wave Dynamics Experiment (SWADE) conducted off Wallops Island, Virginia, from October 1990 to March 1991. Owing to the advection of the Gulf Stream by the semidiurnal tide, the discus buoy was alternately located outside and inside the Gulf Stream. The directional wave measurements from the buoy show the changes in wave direction, wave energy, and directional spreading when waves encountered the current in the Gulf Stream meanders. A wave refraction model, using the ray-tracing method with an estimated Gulf Stream velocity field and meandering condition, was used to simulate wave refraction patterns and to estimate wave parameters at relative locations corresponding to buoy measurements. The numerical simulation shows that a focusing zone of wave rays was formed near the boundary and behind the crest of a simulated Gulf Stream meander. The focusing of wave rays causes changes in wave direction, increases in wave energy, and decreases in wave directional spreading, which are in good agreement with the results from the buoy measurements. C1 NASA,GODDARD SPACE FLIGHT CTR,SCI SYST & APPLICAT INC,GREENBELT,MD 20771. NATL DATA BUOY CTR,BAY ST LOUIS,MS. NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771. RP WANG, DW (reprint author), COMP SCI CORP,BLDG 3203,BAY ST LOUIS,MS 39529, USA. NR 28 TC 10 Z9 11 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1994 VL 99 IS C3 BP 5065 EP 5079 DI 10.1029/93JC02714 PG 15 WC Oceanography SC Oceanography GA NC605 UT WOS:A1994NC60500005 ER PT J AU COMISO, JC AF COMISO, JC TI SURFACE TEMPERATURES IN THE POLAR-REGIONS FROM NIMBUS-7 TEMPERATURE HUMIDITY INFRARED RADIOMETER SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA ICE; AIR-TEMPERATURE; MICROWAVE; CLOUD AB Monthly surface temperatures in the Arctic and Antarctic regions have been derived from the 11.5-mum thermal infrared channel of the Nimbus 7 temperature humidity infrared radiometer (THIR) for a whole year in 1979 and for a winter and a summer month from 1980 through 1985. The data set shows interannual variability and provides spatial details that allow identification of temperature patterns over sea ice and ice sheet surfaces. For example, the coldest spot in the southern hemisphere is observed to be consistently in the Antarctic plateau in the southern hemisphere, while that in the northern hemisphere is usually located in Greenland, or one of three other general areas: Siberia, the central Arctic, or the Canadian Archipelago. Also, in the southern hemisphere, the amplitude of the seasonal fluctuation of ice sheet temperatures is about 3 times that of sea ice, while in the northern hemisphere, the corresponding fluctuations for the two surfaces are about the same. The main sources of error in the retrieval are cloud and other atmospheric effects. These were minimized by first choosing the highest radiance value from the set of measurements during the day taken within a 30 km by 30 km grid of each daily map. Then the difference of daily maps was taken, and where the difference is greater than a certain threshold (which in this case is 12-degrees-C), the data element is deleted. Overall, the monthly maps derived from the resulting daily maps are spatially and temporally consistent. are coherent with the topography of the Antarctic continent and the location of the sea ice edge, and are in qualitative agreement with climatological data. Quantitatively, THIR data are in good agreement with Antarctic ice sheet surface air temperature station data with a correlation coefficient of 0.997 and a standard deviation of 2.0-degrees-C. The absolute values are not as good over the sea ice edges, but a comparison with Russian 2-m drift station temperatures shows very high correlation (with correlation coefficient at 0.998) and a standard deviation of 1.1-degrees-C. Overall, the rms error is estimated to be from 1-degrees to 2-degrees-C, depending on the surface, while the average bias when compared with in situ data is less than 2-degrees-C. RP COMISO, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. NR 35 TC 45 Z9 45 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1994 VL 99 IS C3 BP 5181 EP 5200 DI 10.1029/93JC03450 PG 20 WC Oceanography SC Oceanography GA NC605 UT WOS:A1994NC60500012 ER PT J AU MASSOM, R COMISO, JC AF MASSOM, R COMISO, JC TI THE CLASSIFICATION OF ARCTIC SEA-ICE TYPES AND THE DETERMINATION OF SURFACE-TEMPERATURE USING ADVANCED VERY HIGH-RESOLUTION RADIOMETER DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID LANDSAT SATELLITE IMAGERY; PASSIVE MICROWAVE; AVHRR DATA; INFRARED MEASUREMENTS; OPTICAL-PROPERTIES; THEORETICAL-MODEL; VIEWING ANGLE; SNOW COVER; MU-M; POLYNYAS AB The accurate quantification of new ice and open water areas and surface temperatures within the sea ice packs is a key to the realistic parameterization of heat, moisture, and turbulence fluxes between ocean and atmosphere in the polar regions. Multispectral NOAA advanced very high resolution radiometer/2 (AVHRR/2) satellite images are analyzed to evaluate how effectively the data can be used to characterize sea ice in the Bering and Greenland seas, both in terms of surface type and physical temperature. The basis of the classification algorithm, which is developed using a late wintertime Bering Sea ice cover data, is that frequency distributions of 10.8-mum radiances provide four distinct peaks, representing open water, new ice, young ice, and thick ice with a snow cover. The results are found to be spatially and temporally consistent. Possible sources of ambiguity, especially associated with wider temporal and spatial application of the technique, are discussed. An ice surface temperature algorithm is developed for the same study area by regressing thermal infrared data from 10.8- and 12.0-mum channels against station air temperatures, which are assumed to approximate the skin temperatures of adjacent snow and ice. The standard deviations of the results when compared with in situ data are about 0.5 K over leads and polynyas to about 0.5-1.5 K over thick ice. This study is based upon a set of in situ data limited in scope and coverage. Cloud masks are applied using a thresholding technique that utilizes 3.74- and 10.8-mum channel data. The temperature maps produced show coherence with surface features like new ice and leads, and consistency with corresponding surface type maps. Further studies are needed to better understand the effects of both the spatial and temporal variability in emissivity, aerosol and precipitable atmospheric ice particle distribution, and atmospheric temperature inversions. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771. NR 70 TC 38 Z9 40 U1 3 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1994 VL 99 IS C3 BP 5201 EP 5218 DI 10.1029/93JC03449 PG 18 WC Oceanography SC Oceanography GA NC605 UT WOS:A1994NC60500013 ER PT J AU GLAZMAN, RE AF GLAZMAN, RE TI SURFACE GRAVITY AT EQUILIBRIUM WITH A STEADY WIND SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WAVE SPECTRUM; DIRECTIONAL SPECTRA; SEA; PRESSURE; GROWTH; FETCH; BIAS AB Observations of wave fields' spatial evolution and of gravity, wave spectra S(omega) are analyzed on the basis of the data reported by several research groups as well as on a 2-year data set of wind and wave measurements by stationary National Oceanic and Atmospheric Administration buoys near the Hawaiian Islands. We seek to clarify the role of the wave energy advection (with the wave group velocity) in the overall energy balance. This advective transfer appears to be no less important than the local (breaking wave induced) dissipation as a factor of wind-wave equilibrium. The advection is found to manifest. itself in the shape of wave spectra by reducing the rate at which the spectral density of the wave energy, S(omega) approximately omega(-p), falls off as the frequency increases away from the spectral peak. This and other conclusions are derived by comparing the field observations with theoretical predictions of the weak turbulence theory for a spatially inhomogeneous, statistically stationary, wave field. The observations also indicate that the typical wave age xi = C0/U in the open ocean is much greater than the limiting value 1.2 attributed to the ''fully developed sea.'' Although the observed spectra can be approximated by a power law with a single ''effective'' exponent, this apparent exponent, p, is found to depend on the wave age. At high xi and at frequencies below the generation range, - p tends to - 3 rather than the value of - 11/3 predicted by the Zakharov-Zaslavskii theory. This deviation is interpreted as pointing to a nonconservative nature of the inverse cascade, the latter including a leakage of energy to low-wavenumber modes. Dependence of the overall effective exponent on xi is shown to be responsible for variation in the coefficients b, B, c, C appearing in empirical fetch laws, such as xi = Cx(c) and e = Bx(b), where x and e are the dimensionless fetch and wave energy, respectively. RP GLAZMAN, RE (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 35 TC 11 Z9 11 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1994 VL 99 IS C3 BP 5249 EP 5262 DI 10.1029/93JC03317 PG 14 WC Oceanography SC Oceanography GA NC605 UT WOS:A1994NC60500016 ER PT J AU BANSAL, NP DRUMMOND, CH AF BANSAL, NP DRUMMOND, CH TI KINETIC-STUDY ON THE HEXACELSIAN-CELSIAN PHASE-TRANSFORMATION - COMMENT SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 OHIO STATE UNIV,DEPT MAT SCI & ENGN,COLUMBUS,OH 43210. RP BANSAL, NP (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 6 TC 11 Z9 11 U1 2 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD MAR 15 PY 1994 VL 13 IS 6 BP 423 EP 424 DI 10.1007/BF00278016 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA ND131 UT WOS:A1994ND13100010 ER PT J AU NOEVER, DA CRONISE, RJ AF NOEVER, DA CRONISE, RJ TI FROTH INSTABILITY IN SMALL-OVER-LARGE BUBBLE LATTICES SO PHYSICA D LA English DT Article ID SOAP AB For different bubble diameters arranged in a nearly two-dimensional froth or lattice, a fluid instability is predicted. The first-order stability analysis yields conditions for growth of the most unstable wavenumber both as a function of bubble diameter and dimensionless Bond number. Gravity acts to distribute the greater fluid mass associated with smaller bubbles, while surface tension stabilizes the entire lattice against perturbations. The phenomenon evolves somewhat akin to a Rayleigh-Taylor mechanism and in addition to its fundamental interest, carries implications for predicting solute redistribution and gravitational alignments in bubble columns. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES-76,HUNTSVILLE,AL 35812, USA. NR 16 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD MAR 15 PY 1994 VL 71 IS 4 BP 453 EP 459 DI 10.1016/0167-2789(94)90011-6 PG 7 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA NB490 UT WOS:A1994NB49000008 ER PT J AU KAMIONKOWSKI, M KOSOWSKY, A TURNER, MS AF KAMIONKOWSKI, M KOSOWSKY, A TURNER, MS TI GRAVITATIONAL-RADIATION FROM 1ST-ORDER PHASE-TRANSITIONS SO PHYSICAL REVIEW D LA English DT Article ID COLLIDING VACUUM BUBBLES; FALSE VACUUM; DEFLAGRATION; COLLISIONS; NUCLEATION; INFLATION; GROWTH; WAVES; FATE AB We consider the stochastic background of gravity waves produced by first-order cosmological phase transitions from two types of sources: colliding bubbles and hydrodynamic turbulence. First we discuss the fluid mechanics of relativistic spherical combustion. We then numerically collide many bubbles expanding at a velocity v and calculate the resulting spectrum of gravitational radiation in the linearized gravity approximation. Our results are expressed as simple functions of the mean bubble separation, the bubble expansion velocity, the latent heat, and the efficiency of converting latent heat to kinetic energy of the bubble walls. A first-order phase transition is also likely to excite a Kolmogoroff spectrum of turbulence. We estimate the gravity waves produced by such a spectrum of turbulence and find that the characteristic amplitude of the gravity waves produced is comparable to that from bubble collisions. Finally, we apply these results to the electroweak transition. Using the one-loop effective potential for the minimal electroweak model, the characteristic amplitude of the gravity waves produced is h congruent-to 1.5 x 10(-27) at a characteristic frequency of 4.1 x 10(-3) Hz corresponding to OMEGA approximately 10(-22) in gravity waves, far too small for detection. Gravity waves from more strongly first-order phase transitions, including the electroweak transition in nonminimal models, have better prospects for detection, though probably not by LIGO. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,DEPT PHYS & ASTRON,CHICAGO,IL 60637. UNIV CHICAGO,DEPT ASTRON,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. RP KAMIONKOWSKI, M (reprint author), INST ADV STUDY,SCH NAT SCI,PRINCETON,NJ 08540, USA. NR 36 TC 195 Z9 195 U1 2 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 15 PY 1994 VL 49 IS 6 BP 2837 EP 2851 DI 10.1103/PhysRevD.49.2837 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA NB796 UT WOS:A1994NB79600018 ER PT J AU DOWKER, F GAUNTLETT, JP KASTOR, DA TRASCHEN, J AF DOWKER, F GAUNTLETT, JP KASTOR, DA TRASCHEN, J TI PAIR CREATION OF DILATON BLACK-HOLES SO PHYSICAL REVIEW D LA English DT Article ID SPHERICALLY SYMMETRIC-SOLUTIONS; KALUZA-KLEIN THEORY; CLASSICAL-SOLUTIONS; STRING THEORY; PARTICLES AB We consider dilaton gravity theories in four spacetime dimensions parametrized by a constant a, which controls the dilaton coupling, and construct new exact solutions. We first generalize the C metric of Einstein-Maxwell theory (a = 0) to solutions corresponding to oppositely charged dilaton black holes undergoing uniform acceleration for general a. We next develop a solution-generating technique which allows us to ''embed'' the dilaton C metrics in magnetic dilaton Melvin backgrounds, thus generalizing the Ernst metric of Einstein-Maxwell theory. By adjusting the parameters appropriately, it is possible to eliminate the nodal singularities of the dilaton C metrics. For a < 1 (but not for a greater-than-or-equal-to 1), it is possible to further restrict the parameters so that the dilaton Ernst solutions have a smooth Euclidean section with topology S2 x S2 - {pt}, corresponding to instantons describing the pair production of dilaton black holes in a magnetic field. A different restriction on the parameters leads to smooth instantons for all values of a with topology S2 x R2. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS GRP,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV MASSACHUSETTS,DEPT PHYS & ASTRON,AMHERST,MA 01003. NR 36 TC 157 Z9 158 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 15 PY 1994 VL 49 IS 6 BP 2909 EP 2917 DI 10.1103/PhysRevD.49.2909 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA NB796 UT WOS:A1994NB79600024 ER PT J AU POOL, FS ESSICK, JM SHING, YH MATHER, RT AF POOL, FS ESSICK, JM SHING, YH MATHER, RT TI DEPENDENCE OF THE A-SIH DEFECT DENSITY-OF-STATES ON THE MAGNETIC-FIELD PROFILE OF AN ELECTRON-CYCLOTRON-RESONANCE MICROWAVE PLASMA SO THIN SOLID FILMS LA English DT Article ID AMORPHOUS-SILICON FILMS; SOLAR-CELL; DEPOSITION; BEHAVIOR AB The magnetic field profile of an electron cyclotron resonance microwave plasma was systematically altered to determine subsequent effects on a-Si:H film quality. The mobility gap deep defect density ND, deposition rate and light-to-dark conductivity were determined for the a-Si:H films. By variation of the magnetic field profile ND could be altered by more than an order of magnitude, from 1 x 10(16) to 1 x 10(17) cm-3 at 0.7 mTorr and 1 x 10(16) to 5 X 10(17) cm-1 at 5 mTorr as determined by junction capacitance techniques. Two deposition regimes were found to occur for the conditions of this study. Highly divergent magnetic fields resulted in poor quality a-Si:H, while for magnetic field profiles defining a more highly confined plasma, the a-Si:H was of device quality and relatively independent of the magnetic field configuration. The data is interpreted as a consequence of silane depletion for highly divergent magnetic field profiles. RP POOL, FS (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAR 15 PY 1994 VL 240 IS 1-2 BP 152 EP 156 DI 10.1016/0040-6090(94)90713-7 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA NA905 UT WOS:A1994NA90500029 ER PT J AU NEUDECK, PG LARKIN, DJ POWELL, JA MATUS, LG SALUPO, CS AF NEUDECK, PG LARKIN, DJ POWELL, JA MATUS, LG SALUPO, CS TI 2000-V 6H-SIC P-N-JUNCTION DIODES GROWN BY CHEMICAL-VAPOR-DEPOSITION SO APPLIED PHYSICS LETTERS LA English DT Article AB In this letter we report on the fabrication and initial electrical characterization of the first silicon carbide diodes to demonstrate rectification to reverse voltages in excess of 2000 V at room temperature. The mesa structured 6H-SiC p + n junction diodes were fabricated in 6H-SiC epilayers grown by atmospheric pressure chemical vapor deposition on commercially available 6H-SiC wafers. The devices were characterized while immersed in Fluorinert(TM) to prevent arcing which occurs when air breaks down under high electric fields. The simple nonoptimized diodes, whose device areas ranged from 7 x 10(-6) to 4 x 10(-4) cm2, exhibited a 2000 V functional device yield in excess of 50%. C1 CALSPAN CORP,FAIRVIEW PK,OH 44126. RP NEUDECK, PG (reprint author), NASA,LEWIS RES CTR,MS 77-1,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 13 TC 77 Z9 77 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 14 PY 1994 VL 64 IS 11 BP 1386 EP 1388 DI 10.1063/1.111915 PG 3 WC Physics, Applied SC Physics GA NA496 UT WOS:A1994NA49600025 ER PT J AU DEVINCENZI, DL AF DEVINCENZI, DL TI EXOBIOLOGICAL EXPLORATION OF MARS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 9 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402362 ER PT J AU ALLAMANDOLA, LJ AF ALLAMANDOLA, LJ TI INTERSTELLAR ICE AND DUST - THE FEEDSTOCK OF THE SOLAR-SYSTEM SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,ASTROCHEM LAB,MT VIEW,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 10 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402363 ER PT J AU BERNSTEIN, MP ALLAMANDOLA, LJ SANDFORD, SA CHANG, S AF BERNSTEIN, MP ALLAMANDOLA, LJ SANDFORD, SA CHANG, S TI THE PHOTOPRODUCTION OF ORGANIC-MOLECULES IN COMETARY AND INTERSTELLAR ICE ANALOGS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 11 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402364 ER PT J AU BONTING, SL AF BONTING, SL TI NEEDS FOR BIOSENSORS IN-SPACE BIOLOGY RESEARCH SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,INST SETI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 11 EP BTEC PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501754 ER PT J AU CHANG, S AF CHANG, S TI ORGANIC-CHEMISTRY OF METEORITES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,PLANETARY BRANCH,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 15 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402368 ER PT J AU CHUANG, KC KINDER, JD HULL, DL YOUNGS, WJ AF CHUANG, KC KINDER, JD HULL, DL YOUNGS, WJ TI RODLIKE POLYIMIDES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV AKRON,DEPT CHEM,AKRON,OH 44325. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 17 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501048 ER PT J AU SMITH, JG HERGENROTHER, PM AF SMITH, JG HERGENROTHER, PM TI CHEMISTRY AND PROPERTIES OF PHENYLETHYNYL PHTHALIC-ANHYDRIDE IMIDE OLIGOMERS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 23 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501054 ER PT J AU ZEHE, MJ BALL, DW AF ZEHE, MJ BALL, DW TI MATRIX-ISOLATION SPECTROSCOPY APPLIED TO FLUOROETHER BREAKDOWN SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CLEVELAND STATE UNIV,DEPT CHEM,CLEVELAND,OH 44115. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 28 EP FLUO PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402199 ER PT J AU JONES, WR HERRERAFIERRO, P AJAYI, OO GOODELL, AJ WEDEVEN, LD DEVINE, E PREDMORE, RE AF JONES, WR HERRERAFIERRO, P AJAYI, OO GOODELL, AJ WEDEVEN, LD DEVINE, E PREDMORE, RE TI ENHANCEMENT OF PERFLUOROPOLYETHER BOUNDARY LUBRICATION PERFORMANCE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. WEDEVEN ASSOCIATES INC,EDGEMONT,PA 19028. SWALES & ASSOCIATES,BELTSVILLE,MD 20705. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 29 EP FLUO PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402200 ER PT J AU WEBER, AL AF WEBER, AL TI PREBIOTIC OXIDATIVE POLYMERIZATION OF 2,3-DIMERCAPTOPROPANOL ON THE SURFACE OF IRON(III) HYDROXIDE OXIDE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 43 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402396 ER PT J AU LEE, BL SOUCEK, MD PATER, RH AF LEE, BL SOUCEK, MD PATER, RH TI PROCESSING ISSUES OF TOUGHENED THERMOSETTING POLYIMIDE MATRIX COMPOSITES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 PENN STATE UNIV,DEPT ENGN SCI & MECH,SHARON,PA 16146. NASA,LANGLEY RES CTR,POLYMER MAT BRANCH,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 46 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501505 ER PT J AU FISHER, TH CHAO, P UPTON, CG DAY, AJ AF FISHER, TH CHAO, P UPTON, CG DAY, AJ TI NMR-STUDY ON THE PRODUCTS OF THE REACTIONS OF 4,4'-DIHYDROXYDIPHENYLMETHANE AND 2,4'-DIHYDROXYDIPHENYLMETHANE WITH FORMALDEHYDE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 MISSISSIPPI STATE UNIV,DEPT CHEM,MISSISSIPPI STATE,MS 39762. NASA,MSFC,HUNTSVILLE,AL 35812. THIOKOL HSO,HUNTSVILLE,AL 35806. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 56 EP ORGN PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95500133 ER PT J AU KIM, HL MADOU, M HINES, J AF KIM, HL MADOU, M HINES, J TI TELEMETRIC ION-SELECTIVE ELECTRODES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. MICROFABRICATIONS,PALO ALTO,CA 94306. RI Madou, Marc/E-5869-2013 OI Madou, Marc/0000-0003-4847-3117 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 66 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501525 ER PT J AU JENSEN, BJ BRYANT, RG AF JENSEN, BJ BRYANT, RG TI PHENYLETHYNYL-TERMINATED ARYLENE ETHER ADHESIVES CONTAINING BIPHENYL UNITS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 104 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501136 ER PT J AU BRYANT, RG AF BRYANT, RG TI A SOLUBLE COPOLYIMIDE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 106 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501138 ER PT J AU JENSEN, BJ BRYANT, RG AF JENSEN, BJ BRYANT, RG TI DEVELOPMENT OF A UNIQUE COPOLYIMIDE BACKBONE FOR IMIDE OLIGOMERS WITH TERMINAL REACTIVE GROUPS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. COLL WILLIAM & MARY,WILLIAMSBURG,VA 23185. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 117 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501149 ER PT J AU FAY, CC SMITH, JG STCLAIR, TL AF FAY, CC SMITH, JG STCLAIR, TL TI POTENTIAL LIQUID-CRYSTALLINE POLYIMIDES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 118 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501150 ER PT J AU ROBERTSMCDANIEL, P CONNELL, JW ORWOLL, RA AF ROBERTSMCDANIEL, P CONNELL, JW ORWOLL, RA TI POLY(ARYLENE ETHER-CO-IMIDAZOLE)S AS TOUGHNESS MODIFIERS FOR EPOXY-RESINS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 119 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501151 ER PT J AU DEZERN, JF FAY, CC AF DEZERN, JF FAY, CC TI EFFECT OF THERMAL AGING ON THE THERMOMECHANICAL PROPERTIES OF POLYETHERKETOIMIDES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 120 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501152 ER PT J AU SIOCHI, EJ HAVENS, SJ HERGENROTHER, PM AF SIOCHI, EJ HAVENS, SJ HERGENROTHER, PM TI MOLECULAR-WEIGHT CHARACTERIZATION OF LARC(TM)-CPI 2 POLY(AMIDE ACID) BY SIZE-EXCLUSION CHROMATOGRAPHY DIFFERENTIAL VISCOSITY SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 121 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501153 ER PT J AU HAVENS, SJ BRYANT, RG JENSEN, BJ HERGENROTHER, PM AF HAVENS, SJ BRYANT, RG JENSEN, BJ HERGENROTHER, PM TI PHENYLETHYNYL-TERMINATED IMIDE OLIGOMERS AND POLYMERS THEREFROM SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 124 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501156 ER PT J AU SMITH, GD JAFFE, RL YOON, DY AF SMITH, GD JAFFE, RL YOON, DY TI CONFORMATIONAL CHARACTERISTICS OF POLY(TETRAFLUOROETHYLENE) CHAINS BASED UPON AB-INITIO ELECTRONIC-STRUCTURE CALCULATIONS ON MODEL MOLECULES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 ELORET INST,SUNNYVALE,CA 94087. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95120. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 131 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501163 ER PT J AU MEADOR, MAB AUPING, JV FERRARA, LA GAIER, JR HARDYGREEN, D AF MEADOR, MAB AUPING, JV FERRARA, LA GAIER, JR HARDYGREEN, D TI COMPARISON OF ELECTRICALLY CONDUCTIVE FILMS MADE FROM POLY(3-METHYLTHIOPHENE) OR POLYPYRROLE IN KAPTON SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. UNIV AKRON,AKRON,OH 44325. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 141 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501173 ER PT J AU MARDER, SR AF MARDER, SR TI CAN ACADEMIC STRUCTURE-PROPERTY STUDIES ON NONLINEAR-OPTICAL MATERIALS HAVE AN IMPACT ON POTENTIAL INDUSTRIAL APPLICATIONS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CALTECH,BECKMAN INST,PASADENA,CA 91125. JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 143 EP IEC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402689 ER PT J AU EVANS, BR MARGALIT, R WOODWARD, J AF EVANS, BR MARGALIT, R WOODWARD, J TI VERATRYL ALCOHOL OXIDASE ACTIVITY OF A CHEMICALLY-MODIFIED CELLULASE PROTEIN SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 152 EP BTEC PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501895 ER PT J AU MEADOR, MA ABDULAZIZ, M AF MEADOR, MA ABDULAZIZ, M TI SYNTHESIS AND CHARGE-TRANSFER BEHAVIOR OF SUBSTITUTED 2,3,5,6-TETRAPHENYLBENZO [1,2-B 5,4-B']DIFURANS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,POLYMER BRANCH,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,DEPT CHEM,CLEVELAND,OH 44106. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 158 EP ORGN PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95500235 ER PT J AU TALU, O SHAH, DB STREET, KW PHILIPP, WH WAN, W AF TALU, O SHAH, DB STREET, KW PHILIPP, WH WAN, W TI A NEW ION-EXCHANGE MEDIA FOR THE REMOVAL OF HEAVY-METAL IONS FROM AQUEOUS-SOLUTION SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CLEVELAND STATE UNIV,CTR ADV MFG,CLEVELAND,OH 44115. CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. BIOMET CO,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 217 EP IEC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95402759 ER PT J AU SUTTER, JK JOBE, JM CRANE, EA AF SUTTER, JK JOBE, JM CRANE, EA TI STATISTICAL DESIGN IN THE ISOTHERMAL AGING OF POLYIMIDES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. MIAMI UNIV,OXFORD,OH 45056. JOHN CARROLL UNIV,CLEVELAND,OH 44118. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 242 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501701 ER PT J AU CONNELL, JW SMITH, JG HERGENROTHER, PM AF CONNELL, JW SMITH, JG HERGENROTHER, PM TI PROPERTIES AND POTENTIAL APPLICATIONS OF POLY(ARYLENE ETHER BENZIMIDAZOLE)S SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 261 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501720 ER PT J AU RICH, DC CEBE, P STCLAIR, AK AF RICH, DC CEBE, P STCLAIR, AK TI RELATIONSHIP BETWEEN FLUORINE CONTENT AND REFRACTIVE-INDEX IN AROMATIC POLYIMIDE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 MIT,DEPT MAT SCI & ENGN,CAMBRIDGE,MA 02139. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 264 EP PMSE PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501723 ER PT J AU WROBLESKI, DA BENICEWICZ, BC AF WROBLESKI, DA BENICEWICZ, BC TI CORROSION-RESISTANT COATINGS FROM CONDUCTING POLYMERS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV MAT,POLYMER & COATINGS GRP,LOS ALAMOS,NM 87544. NASA,MAT SCI LAB,KENNEDY SPACE FLIGHT CTR,FL 32899. NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 286 EP POLY PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY955 UT WOS:A1994MY95501317 ER PT J AU WATSON, E CROUSE, DJ MEADOR, MA AF WATSON, E CROUSE, DJ MEADOR, MA TI SYNTHESIS OF 1,4-BIS-AROYLBENZENES AS PRECURSORS TO ELECTRONIC MATERIALS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 TENNESSEE TECHNOL UNIV,DEPT CHEM,COOKEVILLE,TN 38505. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 13 PY 1994 VL 207 BP 305 EP CHED PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA MY954 UT WOS:A1994MY95401135 ER PT J AU ZHOU, SM CAMPBELL, S WU, WS YEH, P LIU, HK AF ZHOU, SM CAMPBELL, S WU, WS YEH, P LIU, HK TI MODIFIED-SIGNED-DIGIT ARITHMETIC FOR MULTIINPUT DIGITAL OPTICAL COMPUTING SO APPLIED OPTICS LA English DT Article DE MODIFIED-SIGNED DIGIT; OPTICAL FAN-OUT ELEMENT; MULTIINPUT DIGITAL OPTICAL COMPUTING ID SYMBOLIC SUBSTITUTION; ADDER; MULTIPLICATION; ELEMENTS AB We propose and demonstrate a modified-signed-digit (MSD) arithmetic to achieve multi-input digital optical computing. Our approach utilizes hybrid addition-subtraction transformation (or weight operation) rules among multiple inputs. This results in operation speeds that exceed those of two-input MSD arithmetic for multi-input computing. Optical implementation of the proposed multi-input MSD arithmetic by utilizing spatial data encoding and an optical fan-out element is also presented and experimentally demonstrated. C1 UNIV CALIF SANTA BARBARA, DEPT ELECT & COMP ENGN, SANTA BARBARA, CA 93106 USA. ROCKWELL INT CORP, CTR SCI, THOUSAND OAKS, CA 91360 USA. RP ZHOU, SM (reprint author), JET PROP LAB, CTR MICROELECTR TECHNOL, PASADENA, CA 91109 USA. RI Yeh, Pochi/A-2109-2010 NR 16 TC 13 Z9 13 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAR 10 PY 1994 VL 33 IS 8 BP 1507 EP 1516 PG 10 WC Optics SC Optics GA NC586 UT WOS:A1994NC58600021 PM 20862178 ER PT J AU TSAI, JC KATZ, N BERTSCHINGER, E AF TSAI, JC KATZ, N BERTSCHINGER, E TI X-RAY-EMISSION FROM A SIMULATED CLUSTER OF GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COOLING FLOWS; GALAXIES, CLUSTERING; HYDRODYNAMICS; INTERGALACTIC MEDIUM; X-RAYS, GALAXIES ID DARK MATTER; COOLING FLOWS; GAS; EVOLUTION; MASS; EINSTEIN; M87 AB Using the 1993 cluster simulation of Katz & White, we analyze the intracluster medium and investigate the accuracy of the standard hydrostatic method for determining cluster masses. We show that the simulated cluster gas is in hydrostatic equilibrium with a subsonic flow toward the center. Inside a radius of approximately 100 kpc, this flow is in a steady state. The cooling time is shorter than a Hubble time within the central 50 kpc. The flow rate is regulated by the gas sink in the middle of the cluster and the PdV work done as the gas flows in, verifying the standard cooling flow scenario. We simulate observations of the cluster using the instrument parameters of the EXOSAT ME detector and the Einstein IPC detector. Even though the intracluster gas is not isothermal, isothermal models of the cluster, excluding regions within 100 kpc of galaxies, fit the EXOSAT X-ray spectra as well as they fit real clusters. The X-ray surface brightness distribution is similar to that of real clusters, again excluding the galaxies. We simulate the procedure used to determine the masses of real clusters. We use the equation of hydrostatic equilibrium together with the temperature derived from an isothermal fit to the simulated EXOSAT spectrum and the density profile derived from a fit to the simulated IPC surface brightness profile to determine the mass. A comparison of the derived mass profile to the actual mass profile shows that errors of a factor of 2 are possible. If the actual temperature profile is used, the cluster mass is found to an accuracy of better than 25% within the virial radius. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP TSAI, JC (reprint author), MIT,DEPT PHYS,6-207,CAMBRIDGE,MA 02139, USA. NR 44 TC 38 Z9 38 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1994 VL 423 IS 2 BP 553 EP 565 DI 10.1086/173834 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA095 UT WOS:A1994NA09500004 ER PT J AU WEAVER, KA MUSHOTZKY, RF ARNAUD, KA SERLEMITSOS, PJ MARSHALL, FE PETRE, R JAHODA, KM SMALE, AP NETZER, H AF WEAVER, KA MUSHOTZKY, RF ARNAUD, KA SERLEMITSOS, PJ MARSHALL, FE PETRE, R JAHODA, KM SMALE, AP NETZER, H TI THE COMPLEX SOFT-X-RAY EXCESS IN NGC-4151 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC 4151); GALAXIES, NUCLEI; GALAXIES, SEYFERT; X-RAYS, GALAXIES ID SEYFERT-GALAXIES; TELESCOPE OBSERVATIONS; LINE REGIONS; SPECTRUM; EMISSION; ABSORPTION; CONSTRAINTS; ULTRAVIOLET; REFLECTION; NGC-1068 AB We present Broad-Band X-ray Telescope (BBXRT) observations (approximately 0.4-11.0 keV) of the Seyfert 1.5 galaxy NGC 4151, with emphasis placed upon modeling the low-energy X-ray spectrum. A prominent soft X-ray ''excess'' below the approximately 2 keV cutoff due to a high absorbing column is known to exist in NGC 4151. This excess has been variously discussed in terms of ''leakage'' through a patchy absorber, the reduced opacity of an ionized absorber, and/or a distinct and possibly spatially extended component. BBXRT, with its combination of moderate resolution and a large bandpass, has allowed the origin of this excess to be tested for the first time over a 2 day period. We find that the approximately 0.4-1.5 keV flux remains essentially constant while the 2-10 keV continuum flux decreases by approximately 40%. We also see no evidence of strong spectral features at energies of less than 1.5 keV. This implies that the excess is neither continuum ''leakage'' nor is it dominated by emission from a 10(6)-10(7) K equilibrium plasma. The best single-component description of the soft excess is scattering of the central continuum into our line of sight by an ''electron scattering zone'' similar to that in the Seyfert 2 galaxy NGC 1068. However, a more likely description of the lack of strong spectral features and the lack of correlated soft-to-hard X-ray variability is that at least two spectral components comprise the soft excess. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. TEL AVIV UNIV,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. TEL AVIV UNIV,WISE OBSERV,IL-69978 TEL AVIV,ISRAEL. UNIV MARYLAND,COLL PK,MD 20742. NR 43 TC 36 Z9 36 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1994 VL 423 IS 2 BP 621 EP 632 DI 10.1086/173840 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA095 UT WOS:A1994NA09500010 ER PT J AU WIEDEMANN, G AYRES, TR JENNINGS, DE SAAR, SH AF WIEDEMANN, G AYRES, TR JENNINGS, DE SAAR, SH TI CARBON-MONOXIDE FUNDAMENTAL BANDS IN LATE-TYPE STARS .3. CHROMOSPHERE OR CO-MOSPHERE SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, STARS; LINE, FORMATION; STARS, CHROMOSPHERES; STARS, LATE-TYPE ID TRANSFORM SPECTROMETER OBSERVATIONS; STELLAR MODEL CHROMOSPHERES; GIANT STARS; OXYGEN ABUNDANCES; QUIET SUN; ARCTURUS; TEMPERATURE; ATMOSPHERE; NITROGEN; SPECTRA AB The strong vibration-rotation lines of CO at 4.6 mum (DELTAv = 1) are unique diagnostics for the thermal conditions in the atmospheric altitude range of late-type stars near and above the temperature minimum in chromospheric models. Exploiting recent improvements in IR instrumentation, we observed a number of cool stars with high spectral resolution (R almost-equal-to 100,000). The analysis of the spectra was based on an earlier theoretical study which had established CO DELTAv = 1 non-LTE spectra as useful probes for stars of spectral type F, G, and K with log g greater-than-or-equal-to 1. No direct chromospheric indicators were detected in the CO spectra. Stellar boundary (CO) temperatures were determined for the program stars and temperature profiles were constructed for alpha Tau, alpha Boo, beta Gem and beta Dra. The CO-based models feature a steady decrease in temperature at the height where the temperature increases in chromospheric models. Further comparison with chromospheric indicators shows an increasing discrepancy between the temperatures determined from CO measurements and those predicted from radiative equilibrium models, respectively, with increasing chromospheric activity. Thermal bifurcation of the stellar surfaces is proposed to reconcile the contradicting scenarios derived based on different spectral diagnostics. C1 EUROPEAN SO OBSERV, D-85748 GARCHING, GERMANY. UNIV COLORADO, CASA, BOULDER, CO 80309 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. RI Jennings, Donald/D-7978-2012 NR 39 TC 46 Z9 46 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1994 VL 423 IS 2 BP 806 EP 816 DI 10.1086/173859 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA095 UT WOS:A1994NA09500029 ER PT J AU DAVILA, JM AF DAVILA, JM TI SOLAR TOMOGRAPHY SO ASTROPHYSICAL JOURNAL LA English DT Article DE METHODS, DATA ANALYSIS; SUN, CORONA AB Tomographic imaging has provided the medical profession with unprecedented three-dimensional views of the internal structure of the human body. Similar techniques can provide solar physicists with an equally spectacular view of the three-dimensional structure of the solar corona, providing a new tool for addressing the problems of coronal structure, energy balance, and evolution. For the reconstruction process, images of the solar corona observed from different angular positions within the ecliptic are needed, and these are not yet available. The purpose is to demonstrate the utility and the practicality of solar tomography with a series of computer simulations of the process, while exploring the sensitivity of the results to some of the parameters of the observing process, e.g., the number of observations, angular spacing, and signal to noise. The results show that tomography can be a powerful technique for determining the three-dimensional nature of active region magnetic fields, coronal loops, helmet streamers, coronal holes, and other structures in the corona. RP DAVILA, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6821,GREENBELT,MD 20771, USA. NR 8 TC 40 Z9 40 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1994 VL 423 IS 2 BP 871 EP 877 DI 10.1086/173864 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA095 UT WOS:A1994NA09500034 ER PT J AU KEENAN, FP DUFTON, PL FEIBELMAN, WA BELL, KL HIBBERT, A STAFFORD, RP AF KEENAN, FP DUFTON, PL FEIBELMAN, WA BELL, KL HIBBERT, A STAFFORD, RP TI N III INTERCOMBINATION LINES IN THE IUE SPECTRA OF GASEOUS NEBULAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; ULTRAVIOLET, ISM ID PLANETARY-NEBULAE; EMISSION-LINES; OPACITY CALCULATIONS; ATOMIC DATA; ELECTRON; DIAGNOSTICS; TRANSITION; PROGRAM; RATIOS; SUN AB Theoretical N III electron density-sensitive emission-line ratios involving intercombination transitions, derived using recent calculations of electron impact excitation rates and oscillator strengths, are presented for R1 = I(1754.0 angstrom)/I(1749.7 angstrom), R2 = I(1752.2 angstrom)/I(1749.7 angstrom), R3 = I(1748.6 angstrom)/I(1749.7 angstrom), and R4 = I(1746.8 angstrom)/I(1749.7 angstrom). The observed values of R1, R2, and R3 for several gaseous nebulae, measured from high-resolution spectra obtained with the International Ultraviolet Explorer (IUE) satellite, imply electron densities that are compatible. However, values of N. derived from the R4 ratio are up to several orders of magnitude smaller than those deduced from R1, R2, and R3, which is probably due to the N III 1746.8 angstrom line being blended with Fe II 1746.8 angstrom. The electron densities deduced from the N III diagnostics are, in some objects, much larger than those estimated from line ratios in nebular ions such as O III, but are in good agreement with values deduced from the chromospheric C II intercombination transitions at approximately 2325 angstrom. These results suggest that in these nebulae the N III emission may also be chromospheric in origin. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. QUEENS UNIV BELFAST,DEPT APPL MATH & THEORET PHYS,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. RP KEENAN, FP (reprint author), QUEENS UNIV BELFAST,DEPT PURE & APPL PHYS,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. NR 25 TC 18 Z9 18 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1994 VL 423 IS 2 BP 882 EP 886 DI 10.1086/173866 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NA095 UT WOS:A1994NA09500036 ER PT J AU CHOI, H MOIN, P KIM, J AF CHOI, H MOIN, P KIM, J TI ACTIVE TURBULENCE CONTROL FOR DRAG REDUCTION IN WALL-BOUNDED FLOWS SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SKIN FRICTION; NUMERICAL-SIMULATION; CHANNEL FLOW; LAYERS; RIBLETS AB The objective of this study is to explore concepts for active control of turbulent boundary layers leading to skin-friction reduction using the direct numerical simulation technique. Significant drag reduction is achieved when the surface boundary condition is modified to suppress the dynamically significant coherent structures present in the wall region. The drag reduction is accompanied by significant reduction in the intensity of the wall-layer structures and reductions in the magnitude of Reynolds shear stress throughout the flow. The apparent outward shift of turbulence statistics in the controlled flows indicates a displaced virtual origin of the boundary layer and a thickened sublayer. Time sequences of the flow fields show that there are essentially two drag-reduction mechanisms. Firstly, within a short time after the control is applied, drag is reduced mainly by deterring the sweep motion without modifying the primary streamwise vortices above the wall. Consequently, the high-shear-rate regions on the wall are moved to the interior of the channel by the control schemes. Secondly, the active control changes the evolution of the wall vorticity layer by stabilizing and preventing lifting of the spanwise vorticity near the wall, which may suppress a source of new streamwise vortices above the wall. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP CHOI, H (reprint author), STANFORD UNIV,CTR TURBULENCE RES,STANFORD,CA 94305, USA. RI Choi, Haecheon/D-1016-2011; OI Choi, Haecheon/0000-0003-0696-847X; Kim, John/0000-0002-6369-9264 NR 35 TC 307 Z9 323 U1 10 U2 56 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAR 10 PY 1994 VL 262 BP 75 EP 110 DI 10.1017/S0022112094000431 PG 36 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA ND143 UT WOS:A1994ND14300003 ER PT J AU SABINE, C REALMUTO, VJ TARANIK, JV AF SABINE, C REALMUTO, VJ TARANIK, JV TI QUANTITATIVE ESTIMATION OF GRANITOID COMPOSITION FROM THERMAL INFRARED MULTISPECTRAL SCANNER (TIMS) DATA, DESOLATION-WILDERNESS, NORTHERN SIERRA-NEVADA, CALIFORNIA SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DECORRELATION; ENHANCEMENT; IMAGES AB We have produced images that quantitatively depict modal and chemical parameters of granitoids using an image processing algorithm called MINMAP that fits Gaussian cur-ves to normalized emittance spectra recovered from thermal infrared multispectral scanner (TIMS) radiance data. We applied the algorithm to TIMS data from the Desolation Wilderness, an extensively glaciated area near the northern end of the Sierra Nevada batholith that is underlain by Jurassic and Cretaceous plutons that range from diorite and anorthosite to leucogranite. The wavelength corresponding to the calculated emittance minimum lambda(min) varies linearly with quartz content, SiO2, and other modal and chemical parameters. Thematic maps of quartz and silica content derived from lambda(min) values distinguish bodies of diorite from surrounding granite, identify outcrops of anorthosite, and separate felsic, intermediate, and mafic rocks. C1 DESERT RES INST, RENO, NV 89506 USA. RP JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 26 TC 29 Z9 33 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 10 PY 1994 VL 99 IS B3 BP 4261 EP 4271 DI 10.1029/93JB03127 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA NB207 UT WOS:A1994NB20700001 ER PT J AU VANDAM, TM HERRING, TA AF VANDAM, TM HERRING, TA TI DETECTION OF ATMOSPHERIC-PRESSURE LOADING USING VERY LONG-BASE-LINE INTERFEROMETRY MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID RADIO INTERFEROMETRY; LINE INTERFEROMETRY; SEA-LEVEL; GEODESY; DEFORMATION; PRECISION; SURFACE; EARTH AB Loading of the Earth by the temporal redistribution of global atmospheric mass is likely to displace the positions of geodetic monuments by tens of millimeters both vertically and horizontally. Estimates of these displacements are determined by convolving National Meteorological Center (NMC) global values of atmospheric surface pressure with Farrell's elastic Green's functions. An analysis of the distances between radio telescopes determined by very long baseline interferometry (VLBI) between 1984 and 1992 reveals that in many of the cases studied there is a significant contribution to baseline length change due to atmospheric pressure loading. Our analysis covers intersite distances of between 1000 and 10,000 km and is restricted Lo those baselines measured more than 100 times. Accounting for the load effects (after first removing a best fit slope) reduces the weighted root-mean-square (WRMS) scatter of the baseline length residuals on 11 of the 22 baselines investigated. The slight degradation observed in the WRMS scatter on the remaining baselines is largely consistent with the expected statistical fluctuations when a small correction is applied to a data set having a much larger random noise. The results from all baselines are consistent with approximately 60% of the computed pressure contribution being present in the VLBI length determinations. Site dependent coefficients determined by fitting local pressure to the theoretical radial displacement are found to reproduce the deformation caused by the regional pressure to within 25% for most inland sites. The coefficients are less reliable at near coastal and island stations. C1 MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02139 USA. RP VANDAM, TM (reprint author), NVI, GODDARD SPACE FLIGHT CTR, CODE 9269, GREENBELT, MD 20771 USA. NR 23 TC 58 Z9 59 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 10 PY 1994 VL 99 IS B3 BP 4505 EP 4517 DI 10.1029/93JB02758 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA NB207 UT WOS:A1994NB20700016 ER PT J AU BAUSCHLICHER, CW AF BAUSCHLICHER, CW TI HEAT OF FORMATION OF THE CH3CO RADICAL SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; ELECTRON CORRELATION; ENERGIES; THERMOCHEMISTRY; KINETICS AB The heat of formation of the CH3CO radical has been determined on several occasions(1-16) (see Table 1). The experimental literature before 1992 supports a value of about -5 kcal/mol for the heat of formation. Yadav and Goddard(17) studied acetaldehyde and its dissociation using relatively low levels of theory. While the calculations illustrated the character of the potential energy surface, they were incapable of accurately determining the heat of formation of CH3CO. The more accurate calculations of Francisco and Abersold(15) support a heat of formation of around -5 kcal/mol, especially if one takes their value from scheme 1 (-4.9 kcal/mol) in preference to their average value. That is, their reaction which involves breaking a C-H bond is expected to be more accurate than their scheme which involved breaking a C-Cl bond, because it is easier to describe a C-H bond than a C-Cl bond. Also in 1991, Radom and co-workers(16) computed the C-H bond energy in acetaldehyde using the G1 approach.(18) Their bond energy (at 0 K) was 3.8 kcal/mol larger than the experimental value (derived from a heat of formation(13) at 298 K of -5.4 kcal/mol). Because the G1 approach is usually accurate to +/-2 kcal/mol, they suggested that the acetyl radical heat of formation was several kcal/mol smaller in magnitude than experiment. Unfortunately, they did not pursue this suggestion as the acetyl radical was only a minor aspect of their study. Recently, Niiranen et al.(14) determined a heat of formation of -2.39 +/- 0.29 kcal/mol for CH3CO from a kinetics study of the reaction CH3CO + HBr. This value supports the suggestion of Radom and co-workers that the older values are too large in magnitude. In this work we determine the heat of formation of CH3CO using high levels of theory in conjunction with large basis sets. In addition, we determine all of the other bond energies in CH3CHO using the G2(MP2) approach.(19) The G2(MP2) approach combines a highly accurate method in small basis sets with a more approximate method in a large basis set and an empirical correction, and it is therefore a very cost effective method of computing bond energies accurate to about +/-2 kcal/mol. RP BAUSCHLICHER, CW (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 39 TC 21 Z9 21 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD MAR 10 PY 1994 VL 98 IS 10 BP 2564 EP 2566 DI 10.1021/j100061a010 PG 3 WC Chemistry, Physical SC Chemistry GA NA046 UT WOS:A1994NA04600010 ER PT J AU KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS VANPARADIJS, J NORRIS, JP PREECE, RD BRIGGS, MS HORACK, JM PENDLETON, GN GREEN, DA AF KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS VANPARADIJS, J NORRIS, JP PREECE, RD BRIGGS, MS HORACK, JM PENDLETON, GN GREEN, DA TI THE RARITY OF SOFT GAMMA-RAY REPEATERS DEDUCED FROM REACTIVATION OF SGR1806-20 SO NATURE LA English DT Article ID HIGH-ENERGY TRANSIENT; SUPERNOVA AB ONLY two different types of gamma-ray transient sources are presently known: over one thousand gamma-ray bursters (GRBs) and only three soft gamma-ray repeaters (SGRs). The latter are distinguished by their propensity for recurrent burst behaviour(1-3), in contrast to the nonrepeating GRB sources. Recurrent emission from one of the repeaters, SGR1900+14, has been detected(4) earlier by the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory. Here we report renewed burst activity from SGR1806-20, the most prolific of the three known SGRs. This detection of reactivation of this source has been rapidly followed by identification of an X-ray counterpart(5,6), which also coincides with a compact radio source(7) now identified as a plerionic (pulsar-powered) supernova remnants. In combination, these results are leading to a convergence of ideas about the nature of SGRs, which can now be firmly identified as neutron stars. That BATSE has detected no new sources in its two and a half years of operation indicates that SGRs are rare in our Galaxy. C1 UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35806. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. ASTRON INST ANTON PANNEKOEK,1098 SJ AMSTERDAM,NETHERLANDS. CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS. GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. CAVENDISH LAB,MULLARD RADIO ASTRON OBSERV,CAMBRIDGE CB3 0HE,CAMBS,ENGLAND. RP KOUVELIOTOU, C (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES66,HUNTSVILLE,AL 35812, USA. RI Green, David/E-9609-2010; Horack, John/J-6670-2016 OI Green, David/0000-0003-3189-9998; NR 23 TC 114 Z9 114 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAR 10 PY 1994 VL 368 IS 6467 BP 125 EP 127 DI 10.1038/368125a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA NA030 UT WOS:A1994NA03000057 ER PT J AU ZARETSKY, EV AF ZARETSKY, EV TI MODELING THE FUTURE WITH METAL-MATRIX COMPOSITES SO MACHINE DESIGN LA English DT Article RP ZARETSKY, EV (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 9 Z9 9 U1 0 U2 0 PU PENTON PUBL INC PI CLEVELAND PA 1100 SUPERIOR AVE, CLEVELAND, OH 44114 SN 0024-9114 J9 MACH DES JI Mach. Des. PD MAR 7 PY 1994 VL 66 IS 5 BP 124 EP & PG 0 WC Engineering, Mechanical SC Engineering GA NB906 UT WOS:A1994NB90600016 ER PT J AU HEADGORDON, M RICO, RJ OUMI, M LEE, TJ AF HEADGORDON, M RICO, RJ OUMI, M LEE, TJ TI A DOUBLES CORRECTION TO ELECTRONIC EXCITED-STATES FROM CONFIGURATION-INTERACTION IN THE SPACE OF SINGLE SUBSTITUTIONS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID COUPLED-CLUSTER APPROACH; MOLECULAR-ORBITAL THEORY; PERTURBATION-THEORY; ABINITIO CALCULATIONS; RESPONSE FUNCTIONS; OPEN-SHELL; ENERGIES; BENZENE AB A perturbative correction to the method of configuration interaction with single substitutions (CIS) is presented. This CIS (D) correction approximately introduces the effect of double substitutions which are absent in CIS excited states. CIS (D) is a second-order perturbation expansion of the coupled-cluster excited state method, restricted to single and double substitutions, in a series in which CIS is zeroth order, and the first-order correction vanishes. CIS(D) excitation energies are size consistent and the calculational complexity scales with the fifth power of molecular size, akin to second-order Moller-Plesset theory for the ground state. Calculations on singlet excited states of ethylene, formaldehyde, acetaldehyde, butadiene and benzene show that CIS (D) is a uniform improvement over CIS. CIS(D) appears to be a promising method for examining excited states of large molecules, where more accurate methods are not feasible. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP HEADGORDON, M (reprint author), UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA. RI Lee, Timothy/K-2838-2012 NR 44 TC 390 Z9 392 U1 3 U2 30 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAR 4 PY 1994 VL 219 IS 1-2 BP 21 EP 29 DI 10.1016/0009-2614(94)00070-0 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA MZ423 UT WOS:A1994MZ42300004 ER PT J AU PARTRIDGE, H BAUSCHLICHER, CW AF PARTRIDGE, H BAUSCHLICHER, CW TI THEORETICAL-STUDY OF THE LOW-LYING STATES OF TIHE+, TINE+, TIAR+, VAR+, CRHE+, CRAR+, FEHE+, FEAR+, COHE+, AND COAR+ SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID METAL; IONS AB The potential energy curves for the manifold of molecular states dissociating to the lowest transition metal ion states derived from the 3d(n+1) and 3d(n)4s(1) occupations have been determined for selected transition-metal ion-rare gas systems. These curves have been computed using large basis sets, and the state-averaged complete-active-space self-consistent-field/multireference configuration interaction level of electron correlation treatment. In general, the families of curves derived from the 3d(n+1) and 3d(n)4s(1) metal occupations are disjoint; however, for Ti+ there is a strong mixing of the 3d(2)4s(1) and 3d(3) asymptotes, because of the small separation between the asymptotes. This mixing leads to a failure of single-reference-based techniques; this is discussed in the context of our previous single-reference-based treatments. RP PARTRIDGE, H (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 16 TC 43 Z9 43 U1 2 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD MAR 3 PY 1994 VL 98 IS 9 BP 2301 EP 2306 DI 10.1021/j100060a016 PG 6 WC Chemistry, Physical SC Chemistry GA MZ513 UT WOS:A1994MZ51300016 ER PT J AU KOHRS, RH HUCKINS, EK AF KOHRS, RH HUCKINS, EK TI SPACE STATION FREEDOM - AN OVERVIEW SO ACTA ASTRONAUTICA LA English DT Editorial Material AB The paper describes the progress which the Space Station Freedom Program has achieved during the fiscal year 1991 and the plans for the future. RP KOHRS, RH (reprint author), NASA,HEADQUARTERS,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAR PY 1994 VL 32 IS 3 BP 221 EP 226 DI 10.1016/0094-5765(94)90055-8 PG 6 WC Engineering, Aerospace SC Engineering GA NE359 UT WOS:A1994NE35900006 ER PT J AU FRAINIER, R GROLEAU, N HAZELTON, L COLOMBANO, S COMPTON, M STATLER, I SZOLOVITS, P YOUNG, L AF FRAINIER, R GROLEAU, N HAZELTON, L COLOMBANO, S COMPTON, M STATLER, I SZOLOVITS, P YOUNG, L TI PI-IN-A-BOX - A KNOWLEDGE-BASED SYSTEM FOR SPACE SCIENCE EXPERIMENTATION SO AI MAGAZINE LA English DT Article AB The principal investigator (PI)-IN-A-BOX knowledge-based system helps astronauts perform science experiments in space. These experiments are typically costly to devise and build and often are difficult to perform. Further, the space laboratory environment is unique; ever changing; hectic; and, therefore, stressful. The environment requires quick, correct reactions to events over a wide range of experiments and disciplines, including ones distant from an astronaut's main science specialty. This environment suggests the use of advanced techniques for data collection, analysis, and decision making to maximize the value of the research performed. PI-IN-A-BOX aids astronauts with quick-look data collection, reduction, and analysis as well as equipment diagnosis and troubleshooting, procedural reminders, and suggestions for high-value departures from the preplanned experiment protocol. The astronauts have direct access to the system, which is hosted on a portable computer in the Space Lab module. The system is in use on the ground for mission training and was used in flight during the October 1993 space life sciences 2 (SLS-2) shuttle mission. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS RES,MOFFETT FIELD,CA 94035. MIT,COMP SCI LAB,CLIN DECIS MAKING GRP,CAMBRIDGE,MA 02139. RP FRAINIER, R (reprint author), RECOM TECHNOL INC,NASA AMES ARTIFICIAL INTELLIGENT RES BRANCH,MT VIEW,CA, USA. OI Szolovits, Peter/0000-0001-8411-6403 NR 5 TC 2 Z9 2 U1 0 U2 0 PU AMER ASSOC ARTIFICIAL INTELL PI MENLO PK PA 445 BURGESS DRIVE, MENLO PK, CA 94025-3496 SN 0738-4602 J9 AI MAG JI AI Mag. PD SPR PY 1994 VL 15 IS 1 BP 39 EP 51 PG 13 WC Computer Science, Artificial Intelligence SC Computer Science GA NC231 UT WOS:A1994NC23100008 ER PT J AU MILLER, DP AF MILLER, DP TI THE LONG-TERM EFFECTS OF SECONDARY SENSING SO AI MAGAZINE LA English DT Article AB To integrate robotics into society, it is first necessary to measure and analyze current societal responses to areas within robotics. This article is the second in a continuing series of reports on the societal effects of various aspects of robotics. In my previous article, I discussed the problems of sensor abuse and outlined a program of treatment. However, despite the wide dissemination of that article, there are still numerous empty beds at the Susan Calvin Clinic for the Prevention of Sensor Abuse. Sensor abuse continues unabated despite strong evidence that there is a better way. In this article, I explore the age-old question, Why does the robotics community look down on efficient sensing systems? C1 JET PROP LAB,ROBOT INTELLIGENT GRP,PASADENA,CA 91109. RP MILLER, DP (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,FAC COMP SCI,BLACKSBURG,VA 24061, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ARTIFICIAL INTELL PI MENLO PK PA 445 BURGESS DRIVE, MENLO PK, CA 94025-3496 SN 0738-4602 J9 AI MAG JI AI Mag. PD SPR PY 1994 VL 15 IS 1 BP 52 EP 56 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA NC231 UT WOS:A1994NC23100009 ER PT J AU STREMEL, PM AF STREMEL, PM TI EFFECT OF REYNOLDS-NUMBER AND TURBULENCE ON AIRFOIL AERODYNAMICS AT 90-DEGREE INCIDENCE SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 31st Aerospace Sciences Meeting CY JAN 11-14, 1993 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB A method has been developed for calculating the viscous flow about airfoils with and without deflected flaps at -90-deg incidence. This method provides for the solution of the unsteady incompressible Navier-Stokes equations by means of an implicit technique. The solution is calculated on a body-fitted computational mesh using a staggered-grid method. The vorticity is defined at the node points, and the velocity components are defined at the mesh-cell sides. The staggered-grid orientation provides for accurate representation of vorticity at the node points and the continuity equation at the mesh-cell centers. The method provides for the noniterative solution of the flowfield and satisfies the continuity equation to machine zero at each time step. The method is evaluated in terms of its ability to predict two-dimensional flow about an airfoil at - 90-deg incidence for varying Reynolds number and laminar/turbulent models. The variations of the average loading and surface pressure distribution due to flap deflection, Reynolds number, and laminar or turbulent now are presented and compared with experimental results. The comparisons indicate that the calculated drag and drag reduction caused by flap deflection and the calculated average surface pressure are in excellent agreement with the measured results at a similar Reynolds number. RP STREMEL, PM (reprint author), NASA,AMES RES CTR,FULL SCALE AERODYNAM RES DIV,ROTORCRAFT AEROMECH BRANCH,MOFFETT FIELD,CA 94035, USA. NR 13 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 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1994 VL 32 IS 3 BP 449 EP 454 DI 10.2514/3.12007 PG 6 WC Engineering, Aerospace SC Engineering GA MY520 UT WOS:A1994MY52000001 ER PT J AU LEE, SG AF LEE, SG TI REDUCTION OF BLADE-VORTEX INTERACTION NOISE THROUGH POROUS LEADING-EDGE SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 31st Aerospace Sciences Meeting CY JAN 11-14, 1993 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB The effect of the porous leading edge of an airfoil on the blade-vortex interaction noise, which dominates the far-field acoustic spectrum of the helicopter, is investigated. The thin-layer Navier-Stokes equations are solved with a high-order upwind-biased scheme and a multizonal grid system. The Baldwin-Lomax turbulence model is modified for considering transpiration on the surface. The amplitudes of the propagating acoustic wave in the near field are calculated directly from the computation. The porosity effect on the surface is modeled in two ways: 1) imposition of prescribed transpiration velocity distribution and 2) calculation of transpiration velocity distribution by Darcy's law. Results show leading-edge transpiration can suppress pressure fluctuations at the leading edge during blade-vortex interaction and consequently reduce the amplitude of propagating noise by 30% at a maximum in the near field. RP LEE, SG (reprint author), NASA,MOFFETT FIELD,CA 94035, USA. NR 31 TC 13 Z9 13 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1994 VL 32 IS 3 BP 480 EP 488 DI 10.2514/3.12011 PG 9 WC Engineering, Aerospace SC Engineering GA MY520 UT WOS:A1994MY52000005 ER PT J AU DAS, R MAVRIPLIS, DJ SALTZ, J GUPTA, S PONNUSAMY, R AF DAS, R MAVRIPLIS, DJ SALTZ, J GUPTA, S PONNUSAMY, R TI DESIGN AND IMPLEMENTATION OF A PARALLEL UNSTRUCTURED EULER SOLVER USING SOFTWARE PRIMITIVES SO AIAA JOURNAL LA English DT Article ID MULTIPROCESSORS; ALGORITHMS; GRIDS AB This paper is concerned with the implementation of a three-dimensional unstructured-grid Euler solver on massively parallel distributed-memory computer architectures. The goal is to minimize solution time by achieving high computational rates with a numerically efficient algorithm. An unstructured multigrid algorithm with an edge-based data structure has been adopted, and a number of optimizations have been devised and implemented to accelerate the parallel computational rates. The implementation is carried out by creating a set of software tools, which provide an interface between the parallelization issues and the sequential code, while providing a basis for future automatic run-time compilation support. Large practical unstructured grid problems are solved on the Intel iPSC/860 hypercube and Intel Touchstone Delta machine. The quantitative effects of the various optimizations are demonstrated, and we show that the combined effect of these optimizations leads to roughly a factor of 3 performance improvement. The overall solution efficiency is compared with that obtained on the Cray Y-MP vector supercomputer. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. NR 21 TC 19 Z9 19 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1994 VL 32 IS 3 BP 489 EP 496 DI 10.2514/3.12012 PG 8 WC Engineering, Aerospace SC Engineering GA MY520 UT WOS:A1994MY52000006 ER PT J AU ATKINS, H CASPER, J AF ATKINS, H CASPER, J TI NONREFLECTIVE BOUNDARY-CONDITIONS FOR HIGH-ORDER METHODS SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 31st Aerospace Sciences Meeting CY JAN 11-14, 1993 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT ID HYPERBOLIC SYSTEMS AB A different approach to nonreflective boundary conditions for the Euler equations is presented. This work is motivated by a need for inflow and outflow boundary conditions that do not limit the useful accuracy of high-order accurate methods. The primary interest is in the propagation and convection of continuous acoustic and convective waves. This new approach employs the exact solution to finite waves to relate interior values and ambient conditions to boundary values. The method is first presented in one dimension and then generalized to multidimensions. Grid refinement studies are used to demonstrate high-order convergence for both one-dimensional and two-dimensional flows. C1 VIGYAN INC,HAMPTON,VA 23666. RP ATKINS, H (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,HAMPTON,VA 23665, USA. NR 13 TC 17 Z9 17 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1994 VL 32 IS 3 BP 512 EP 518 DI 10.2514/3.12015 PG 7 WC Engineering, Aerospace SC Engineering GA MY520 UT WOS:A1994MY52000009 ER PT J AU CHANDRASEKHARA, MS CARR, LW WILDER, MC AF CHANDRASEKHARA, MS CARR, LW WILDER, MC TI INTERFEROMETRIC INVESTIGATIONS OF COMPRESSIBLE DYNAMIC STALL OVER A TRANSIENTLY PITCHING AIRFOIL SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 31st Aerospace Sciences Meeting CY JAN 11-14, 1993 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT ID CONSTANT-RATE; MOTIONS AB The compressible dynamic stall flowfield over a NACA 0012 airfoil transiently pitching from 0 to 60 deg at a constant rate under compressible flow conditions has been studied using real-time interferometry. A quantitative description of the overall flowfield, including the finer details of dynamic stall vortex formation, growth, and the concomitant changes in the airfoil pressure distribution, has been provided by analyzing the interferograms. For Mach numbers above 0.4, small multiple shocks appear near the leading edge and are present through the initial stages of dynamic stall. Dynamic stall was found to occur coincidentally with the bursting of the separation bubble over the airfoil. Compressibility was found to confine the dynamic stall vortical structure closer to the airfoil surface. The measurements show that the peak suction pressure coefficient drops with increasing freestream Mach number, and also it lags the steady now values at any given angle of attack. As the dynamic stall vortex is shed, an anti-clockwise vortex is induced near the trailing edge, which actively interacts with the post-stall flow. C1 NAVAL POSTGRAD SCH,MONTEREY,CA 93943. MCAT INST,SAN JOSE,CA 95127. RP CHANDRASEKHARA, MS (reprint author), NASA,AMES RES CTR,JOINT INST AERONAUT,DEPT AERONAUT & ASTRONAUT,MS 260-1,MOFFETT FIELD,CA 94035, USA. NR 17 TC 12 Z9 12 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1994 VL 32 IS 3 BP 586 EP 593 DI 10.2514/3.12025 PG 8 WC Engineering, Aerospace SC Engineering GA MY520 UT WOS:A1994MY52000019 ER PT J AU UNGAR, AA AF UNGAR, AA TI WAKES AND WAVES IN N-DIMENSIONS - COMMENT SO AMERICAN JOURNAL OF PHYSICS LA English DT Note RP UNGAR, AA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD MAR PY 1994 VL 62 IS 3 BP 279 EP 279 DI 10.1119/1.17613 PG 1 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA MZ333 UT WOS:A1994MZ33300018 ER PT J AU ANDERSEN, JL ANDERSEN, LJ THRASHER, TN KEIL, LC RAMSAY, DJ AF ANDERSEN, JL ANDERSEN, LJ THRASHER, TN KEIL, LC RAMSAY, DJ TI LEFT-HEART AND ARTERIAL BARORECEPTORS INTERACT IN CONTROL OF PLASMA VASOPRESSIN, RENIN, AND CORTISOL IN AWAKE DOGS SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE BLOOD PRESSURE; CARDIAC RECEPTORS; ANTIDIURETIC HORMONE; ADRENOCORTICOTROPIC HORMONE; ATRIAL NATRIURETIC PEPTIDE; ANGIOTENSIN ID LEFT ATRIAL PRESSURE; CONSCIOUS DOGS; VENTRICULAR RECEPTORS; NATRIURETIC PEPTIDES; CARDIAC RECEPTORS; RELEASE; SECRETION; HYPOTENSION; INHIBITION; HEMORRHAGE AB Arterial hypotension induced by constriction of the ascending aorta (AA) causes increases in left atrial pressure (LAP) and plasma atrial natriuretic peptide (ANP), but no change in plasma arginine vasopressin (AVP), plasma renin activity (PRA), or cortisol. In the present study, we tested the hypothesis that the rise in left heart pressure during constriction of the AA suppressed the stimulation of AVP, renin, and cortisol secretion in response to arterial hypotension. Dogs were prepared with inflatable cuffs around the AA, the pulmonary artery (PA), and the thoracic inferior vena cava (IVC) and with catheters in the left and right atria and abdominal aorta. In one series of experiments, the AA was constricted to lower mean arterial pressure (MAP) 10 or 20% below control for 15 min. Then, either the PA or the IVC was constricted to bring LAP back to control levels but without altering the degree of arterial hypotension. Constriction of the AA alone led to significant increases in LAP and plasma ANP but no change in plasma AVP, cortisol, or PRA. Reducing LAP to control levels by constriction of either the PA or IVC led to significant and similar increases in plasma AVP, cortisol, and PRA. Plasma ANP fell significantly 10 min after LAP was normalized by constriction of the NC but not when LAP was normalized by constriction of the PA, because PA constriction caused a significant rise in right atrial pressure that stimulated ANP secretion. The increases in plasma AVP and PRA after normalizing LAP by constriction of the PA were compared with the increases obtained during identical falls in MAP induced by constriction of the IVC alone, a maneuver that lowers LAP below control. The increases in plasma AVP in the two conditions were identical, indicating that the stimulation of left heart baroreceptors alone can account for the suppression of AVP secretion in response to unloading arterial baroreceptors. In contrast, there was a greater rise in PRA during hypotension caused by constriction of the NC alone compared with the condition in which LAP was normalized but plasma ANP remained elevated. This suggests that increased left heart pressure inhibits renin secretion in response to arterial hypotension by reflex mechanisms and by increased plasma ANP concentration. C1 UNIV CALIF SAN FRANCISCO,SCH MED,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FU NHLBI NIH HHS [HL-41156, HL-41313] NR 31 TC 21 Z9 21 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0002-9513 J9 AM J PHYSIOL JI Am. J. Physiol. PD MAR PY 1994 VL 266 IS 3 BP R879 EP R888 PN 2 PG 10 WC Physiology SC Physiology GA NF861 UT WOS:A1994NF86100084 PM 8160884 ER PT J AU ODONNELL, CP THOMPSON, CJ KEIL, LC THRASHER, TN AF ODONNELL, CP THOMPSON, CJ KEIL, LC THRASHER, TN TI RENIN AND VASOPRESSIN RESPONSES TO GRADED REDUCTIONS IN ATRIAL PRESSURE IN CONSCIOUS DOGS SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE ARTERIAL BARORECEPTORS; CAROTID SINUS RECEPTORS; CARDIAC RECEPTORS; PLASMA RENIN ACTIVITY; ARGININE VASOPRESSIN; ANTIDIURETIC HORMONE; BLOOD PRESSURE ID ARTERIAL BARORECEPTORS; PLASMA VASOPRESSIN; CARDIAC RECEPTORS; ANESTHETIZED DOGS; HEMORRHAGE; SECRETION; BLOCKADE; RELEASE AB Hypovolemia activates reflexes that stimulate secretion of renin and arginine vasopressin (AVP). A large body of evidence, obtained mainly in anesthetized preparations, supports the hypothesis that unloading cardiac receptors stimulates increases in plasma AVP and renin activity (PRA). We have observed significant increases in PRA before any change in either mean arterial pressure (MAP) or pulse pressure in conscious dogs undergoing continuous hemorrhage; however, plasma AVP did not change until there was a significant fall in MAP. These results are compatible with the hypothesis that cardiac receptors cause reflex stimulation of renin but not AVP secretion. The aim of the present study was to test the hypothesis that a decrease in atrial pressure alone is sufficient to stimulate an increase in plasma AVP and PRA. Graded thoracic inferior vena caval constriction (TTVCC) was used to reduce atrial pressure in four steps without altering MAP in conscious dogs. In a fifth step, TIVCC was increased to cause a fall in MAP. A reduction in left atrial pressure (LAP) of 4.2 +/- 0.9 mmHg was accompanied by a significant (P < 0.05) increase in PRA from a control value of 0.4 +/- 0.1 ng angiotensin I (ANG I).ml(-1).3 h(-1) to 1.1 +/- 0.2 ng ANG I.ml(-1).3 h(-1) but no change in plasma AVP (from 1.0 +/- 0.1 to 1.2 +/- 0.2 pg/ml) or MAP (from 85 +/- 5 mmHg to 86 +/- 4 mmHg). Reducing LAP by 7.5 +/- 1.0 mmHg below control stimulated a further increase in PRA (1.8 +/- 0.5 ng ANG I.ml(-l).3 h(-1)) but no change in plasma AVP (3.7 +/- 1.7 pg/ml) or MAP (84 +/- 4 mmHg). Increasing TIVCC enough to cause a fall in MAP (25 +/- 4 mmHg below control) was accompanied by a significant increase in plasma AVP (20 +/- 3 pg/ml above control). These results demonstrate that unloading cardiac receptors alone is sufficient to stimulate an increase in renin but not AVP secretion in conscious dogs. The results suggest that arterial pressure is the critical variable in the AVP response to acute hypovolemia. C1 UNIV CALIF SAN FRANCISCO,SCH MED,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FU NHLBI NIH HHS [HL-41313] NR 28 TC 13 Z9 13 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0002-9513 J9 AM J PHYSIOL JI Am. J. Physiol. PD MAR PY 1994 VL 266 IS 3 BP R714 EP R721 PN 2 PG 8 WC Physiology SC Physiology GA NF861 UT WOS:A1994NF86100063 PM 8160864 ER PT J AU RUBINSTEIN, R GREENBERG, PS AF RUBINSTEIN, R GREENBERG, PS TI RAPID INVERSION OF ANGULAR DEFLECTION DATA FOR CERTAIN AXISYMMETRICAL REFRACTIVE-INDEX DISTRIBUTIONS SO APPLIED OPTICS LA English DT Note DE TOMOGRAPHY; ABEL INVERSION AB Certain functions useful for representing axisymmetric refractive-index distributions are shown to have exact solutions for Abel transformation of the resulting angular deflection data. C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP RUBINSTEIN, R (reprint author), SVERDRUP TECHNOL INC, LEWIS RES CTR GRP, BROOKPARK, OH 44142 USA. NR 5 TC 15 Z9 15 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAR 1 PY 1994 VL 33 IS 7 BP 1141 EP 1144 PG 4 WC Optics SC Optics GA NB422 UT WOS:A1994NB42200002 PM 20862129 ER PT J AU DEROCHEMONT, LP MARONI, VA KLUGERMAN, M ANDREWS, RJ KELLIHER, WC AF DEROCHEMONT, LP MARONI, VA KLUGERMAN, M ANDREWS, RJ KELLIHER, WC TI FABRICATING MULTIFILAMENTARY HIGH-TC SUPERCONDUCTING BISMUTH CUPRATE TAPES BY METALORGANIC CHEMICAL SPRAY-PYROLYSIS SO APPLIED SUPERCONDUCTIVITY LA English DT Article ID CA-CU-O; ORGANIC-ACID SALTS; THIN-FILMS; PHASE; FIBERS; WIRES; DECOMPOSITION; YBA2CU3O7-X; PRECURSORS AB This paper reports preliminary findings on research to develop chemical spray pyrolysis as a method for synthesizing multifilamentary bismuth cuprate (BSCCO) tape and wire components. Chemical spray pyrolysis is a solution process that allows oxide precursor material to be rapidly deposited on a variety of substrate materials. It is an inherently low cost manufacturing process that can be scaled to deposit chemically uniform ceramic coatings over arbitrarily large surface areas. BSCCO tapes have been successfully fabricated from ceramic precursor sprays pyrolyzed onto silver substrates and packaged in a silver sheath. Findings related to solution chemistry, the deposition process, tape construction, and thermomechanical processing that impact the ability to fabricate high-T(c) superconducting wire and tape using this technique are presented and discussed. C1 ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439. ROME LAB,DIV ELECTROMAGNET MAT TECHNOL,BEDFORD,MA 01731. NASA,LANGLEY RES CTR,ENGN LAB UNIT,HAMPTON,VA 23681. RP DEROCHEMONT, LP (reprint author), RADIAT MONITORING DEVICES INC,44 HUNT ST,WATERTOWN,MA 02172, USA. NR 30 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD MAR-APR PY 1994 VL 2 IS 3-4 BP 281 EP 294 DI 10.1016/0964-1807(94)90014-0 PG 14 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA NT631 UT WOS:A1994NT63100014 ER PT J AU OEGERLE, WR HILL, JM AF OEGERLE, WR HILL, JM TI DYNAMICS OF CD CLUSTERS OF GALAXIES .2. ANALYSIS OF 7 ABELL CLUSTERS SO ASTRONOMICAL JOURNAL LA English DT Article ID CENTRAL DOMINANT GALAXIES; RAY LUMINOUS CLUSTERS; RICH CLUSTERS; VELOCITY DISPERSIONS; MULTIPLE NUCLEI; COOLING FLOWS; EVOLUTION; CANNIBALISM; SPECTROSCOPY; RELAXATION AB We have investigated the dynamics of the seven rich Abell clusters A193, A399, A401, A1795, A1809, A2063, and A2124, based on redshift data reported previously by us [Hill & Oegerle, AJ, 106, 831 (1993)]. These papers present the initial results of a survey of cD cluster kinematics, with an emphasis on studying the nature of peculiar velocity cD galaxies and their parent clusters. In the current sample, we find no evidence for significant peculiar cD velocities, with respect to the global velocity distribution. However, the cD in A2063 has a significant (3sigma) peculiar velocity with respect to galaxies in the inner 1.5h-1 Mpc, which is likely due to the merger of a subcluster with A2063. We also find significant evidence for subclustering in A1795, and a marginally peculiar cD velocity with respect to galaxies within approximately 200h-1 kpc of the cD. The available x-ray, optical, and galaxy redshift data strongly suggest that a subcluster has merged with A1795. We propose that the subclusters which merged with A1795 and A2063 were relatively small, with shallow potential wells, so that the cooling flows in these clusters were not disrupted. Two-body gravitational models of the A399/401 and A2063/MKW3S systems indicate that A399/401 is a bound pair with a total virial mass of approximately 4 X 10(15)h-1 M., while A2063 and MKW3S are ve unlikely to be bound. C1 UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP OEGERLE, WR (reprint author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA. RI Oegerle, William/C-9070-2012 NR 44 TC 59 Z9 60 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 1994 VL 107 IS 3 BP 857 EP 867 DI 10.1086/116899 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ128 UT WOS:A1994MZ12800001 ER PT J AU SHRADER, CR WEBB, JR BALONEK, TJ BROTHERTON, MS WILLS, BJ WILLS, D GODLIN, SD SMITH, AG MCCOLLUM, B AF SHRADER, CR WEBB, JR BALONEK, TJ BROTHERTON, MS WILLS, BJ WILLS, D GODLIN, SD SMITH, AG MCCOLLUM, B TI OPTICAL AND ULTRAVIOLET OBSERVATIONS OF 3C-279 DURING OUTBURST SO ASTRONOMICAL JOURNAL LA English DT Article ID QUASAR 3C-279; PHOTOMETRY; BLAZARS; EXCESS AB An ongoing program of photometric monitoring of selected active galactic nuclei has revealed a significant outburst in the optically violently variable QSO 3C 279. The event occurred during May and June of 1992, and was characterized by a peak amplitude of 2.3 mag in the R band. We obtained nearly simultaneous optical and ultraviolet spectroscopy from 1150 to 8600 angstrom of the source at the approximate midpoint of the outburst. The outburst spectrum is well represented by a power law with index alpha = -1.77 (where F(nu) is-proportional-to nu(alpha)) which is relatively flat in comparison with typical quiescent spectra for this source. No emission features are discernable in our data, nor is there any significant Lyman-edge absorption. The observations and data analysis procedures are described, and the resulting photometric light curves and spectra are presented. We also present a long baseline photometric light curve for context. Comparisons with previously published optical-UV outburst and quiescent spectra are made, and luminosity-dependent spectral variations are discussed. C1 FLORIDA INT UNIV,DEPT PHYS,MIAMI,FL 33199. COLGATE UNIV,DEPT PHYS & ASTRON,HAMILTON,NY 13346. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. UNIV TEXAS,MCDONALD OBSERV,AUSTIN,TX 78712. VASSAR COLL,DEPT PHYS & ASTRON,POUGHKEEPSIE,NY 12601. NASA,GODDARD SPACE FLIGHT CTR,IUE OBSERV,GREENBELT,MD 20771. RP SHRADER, CR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 19 TC 14 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 1994 VL 107 IS 3 BP 904 EP 909 DI 10.1086/116904 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ128 UT WOS:A1994MZ12800006 ER PT J AU ELSTON, R MCCARTHY, PJ EISENHARDT, P DICKINSON, M SPINRAD, H JANUZZI, BT MALONEY, P AF ELSTON, R MCCARTHY, PJ EISENHARDT, P DICKINSON, M SPINRAD, H JANUZZI, BT MALONEY, P TI THE SEYFERT-II NATURE OF THE IRAS SOURCE FSC-10214+4724 SO ASTRONOMICAL JOURNAL LA English DT Article ID HIGH-REDSHIFT; SOURCE FSC-10214+4724; ALPHA EMISSION; RADIO GALAXIES; CO EMISSION; QUASARS; LINES; IDENTIFICATIONS; CLASSIFICATION; DISTRIBUTIONS AB We have observed the rest-frame optical and UV spectra of the luminous, high redshift IRAS source FSC 10214 + 4724. We find the optical emission lines to be characterized by ratios similar to those found in Seyfert II galaxies. We support the conclusion of previous work that the UV emission lines are similar to those attributed to AGN rather than to star formation. The ratio Halpha/Hbeta greater-than-or-equal-to 20 (2sigma lower limit) implies substantial reddening of the narrow line region with A(V) > 5.5, sufficient to hide a broad line region in our Halpha observations. Given this large inferred reddening and the strength of the UV continuum and emission lines, we conclude (as have others) that simple screen models of reddening are not appropriate for this object. These properties are very similar to those of the infrared luminous galaxies at lower redshift, suggesting that FSC 10214 + 4724 is the luminous extreme of the same population. We also present H band (1.6 mum) imaging polarimetry observations and find that the rest-frame optical emission is unpolarized (P = 3.2% +/- 2.0%). This deep image of the field shows FSC 10214 + 4724 to possess an unresolved core, with several companions located within 10'' of the point source. We find it unlikely that this group of objects is physically associated with FSC 10214 + 4724 at z = 2.3, and we argue that their magnitudes and colors are more consistent with those expected for galaxies in a foreground group. While galaxy number counts would suggest that such a projection has a low probability of being observed randomly, a foreground group might gravitational lens the z = 2.3 source, making such random statistics inappropriate, and contribute to the large observed luminosity of FSC 10214 + 4724. Comparison of H band images taken on two occasions one year apart show that FSC 10214 + 4724 had varied by 0. 16 +/- 0.03 mag relative to a nearby star during that time. The UV-optical emission line spectra, the bright dereddened continuum magnitude (K less-than-or-equal-to 12) of the unresolved core, its extremely large bolometric luminosity, strong UV polarization, and possible variability all suggest that FSC 10214 + 4724 harbors an obscured AGN. Given that we observe no spectral features attributable to star formation, it appears either that star formation in FSC 10214 + 4724 is more highly obscured at optical and UV wavelengths than the narrow line region of the AGN, or that the AGN (rather than star formation) dominates the large luminosity of this object. C1 CARNEGIE INST WASHINGTON OBSERV,PASADENA,CA 91101. JET PROP LAB,PASADENA,CA 91109. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. INST ADV STUDY,PRINCETON,NJ 08540. UNIV COLORADO,JILA,BOULDER,CO 80309. RP ELSTON, R (reprint author), CERRO TOLOLO INTERAMER OBSERV,CASILLA 603,LA SERENA,CHILE. NR 63 TC 53 Z9 53 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 1994 VL 107 IS 3 BP 910 EP & DI 10.1086/116905 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ128 UT WOS:A1994MZ12800007 ER PT J AU MALUMUTH, EM HEAP, SR AF MALUMUTH, EM HEAP, SR TI UBV STELLAR PHOTOMETRY OF THE 30 DORADUS REGION OF THE LARGE MAGELLANIC CLOUD WITH THE HUBBLE-SPACE-TELESCOPE SO ASTRONOMICAL JOURNAL LA English DT Article ID H-II REGIONS; PLANETARY CAMERA; MASSIVE STARS; EVOLUTION; IMAGES; LMC; 30-DORADUS; CLUSTERS; EMISSION; GALAXY AB We report on Planetary Camera observations of the central region of 30 Doradus in the Large Magellanic Cloud. These images of 30 Doradus are the first ''deep'' HST exposures that have appropriate photometric calibration. The B band (F439W) image, which shows R136a at the center of the PC6 CCD chip, reveals over 200 stars within 3'' of the center of R136a, and over 800 stars in a 35'' X 35'' area. We used Malumuth et al.'s [The First Year of HST Observations, edited by A. L. Kinney and J. C. Blades (ST ScI, Baltimore) (1991)] PSF-fitting method to measure the magnitudes of all stars on the PC6 chip. These new B magnitudes, along with U and V magnitudes from archival PC images, yield a luminosity function, mass density profile, and initial mass function of the 30 Doradus ionizing cluster. The mass distribution is well fit by a King model with a core radius, R(c) = 0.96'' (0.24 pc), a tidal radius, R(t) = 110'' (28 pc), and a total mass, M = 16 800M.. Both the luminosity function and initial mass function show evidence for mass segregation, in the sense that the central region has a higher fraction of massive stars than the outer regions. This is the first observational evidence for mass segregation in a very young cluster (age approximately 3 million years). The observations admit the hypothesis that the mass segregation occurred in the process of star formation and/or that the mass segregation is the result of dynamical evolution. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP MALUMUTH, EM (reprint author), COMP SCI CORP,GODDARD SPACE FLIGHT CTR,GHRS SCI TEAM,ASTRON PROGRAMS,CODE 681,GREENBELT,MD 20771, USA. NR 43 TC 78 Z9 78 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 1994 VL 107 IS 3 BP 1054 EP & DI 10.1086/116917 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ128 UT WOS:A1994MZ12800019 ER PT J AU HARMON, JK OSTRO, SJ CHANDLER, JF HUDSON, RS AF HARMON, JK OSTRO, SJ CHANDLER, JF HUDSON, RS TI RADAR RANGING TO GANYMEDE AND CALLISTO SO ASTRONOMICAL JOURNAL LA English DT Article ID GALILEAN SATELLITES; ECLIPSES; MARS AB Arecibo observations from 1992 February to March have yielded the first successful radar range measurements to the Galilean satellites. Round-trip time delays were measured for Ganymede and Callisto with accuracies of 20-50 mus (3-7 km) and 90 mus ( 14 km), respectively. Both satellites showed round-trip delay residuals (relative to the E-3 ephemeris) of about a millisecond, most of which can be attributed to errors in the predicted along-track positions (orbital phases). Using a simple model that assumed that all of the ephemeris error was due to constant orbital phase and Jupiter range errors, we estimate that Ganymede was leading its ephemeris by 122 +/- 4 km, Callisto was lagging its ephemeris by 307 +/- 14 km, and Jupiter was 11 +/- 4 km more distant than predicted by the PEP740 planetary ephemeris. C1 JET PROP LAB,PASADENA,CA 91109. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. WASHINGTON STATE UNIV,SCH ELECT ENGN & COMP SCI,PULLMAN,WA 99164. RP HARMON, JK (reprint author), NATL ASTRON & IONOSPHERE CTR,ARECIBO,PR 00613, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 1994 VL 107 IS 3 BP 1175 EP 1181 DI 10.1086/116929 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ128 UT WOS:A1994MZ12800031 ER PT J AU COLAVITA, MM AF COLAVITA, MM TI MEASUREMENT OF THE ATMOSPHERIC LIMIT TO NARROW-ANGLE INTERFEROMETRIC ASTROMETRY USING THE MARK-III STELLAR INTERFEROMETER SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ATMOSPHERIC EFFECTS; INSTRUMENTATION, INTERFEROMETERS; METHODS, OBSERVATIONAL; TECHNIQUES, INTERFEROMETRIC; ASTROMETRY; STARS, ALPHA GEM ID LIMITATIONS AB Measurements were made with the Mark III stellar interferometer in order to verify predictions for the accuracy of very-narrow-angle interferometric astrometry. The Mark III was modified to observe simultaneously on its 12-m baseline the phase of the fringe packets of the primary and secondary of the long-period visual binary star alpha Gem. The residuals of the phase difference between primary and secondary were analyzed for 6 data segments taken over two nights. Examination of the Allan variances of the data out to a measurement limit of 8 min indicates that the error is white, as predicted. The mean fluctuations of the residuals corresponds to an astrometric accuracy of 21 muas/square-root h, which is in good agreement with the predictions of atmospheric models. An accurate separation for alpha Gem was also determined: 3.281'' +/- 0.01'' at position angle 73.23-degrees +/- 0.15-degrees for B1992.95 89. RP COLAVITA, MM (reprint author), JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 13 TC 28 Z9 28 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 1994 VL 283 IS 3 BP 1027 EP 1036 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NC576 UT WOS:A1994NC57600042 ER PT J AU PILDIS, RA BREGMAN, JN SCHOMBERT, JM AF PILDIS, RA BREGMAN, JN SCHOMBERT, JM TI EXTRAPLANAR EMISSION-LINE GAS IN NGC-891 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC-891); GALAXIES, ISM; GALAXIES, KINEMATICS AND DYNAMICS; GALAXIES, SPIRAL ID INTERSTELLAR-MEDIUM; H-I; GALAXY NGC-891; IONIZED-GAS; SUPERSHELLS; NGC-4565; DISK; EDGE AB We have used spectroscopy and high-resolution imaging to study the disk-halo interaction in the edge-on spiral galaxy NGC 891, which is known to have extraplanar gas. Halpha imaging of the northeast side of this galaxy reveals diffuse emission-line gas both above and below the plane, as well as new bubble-like structures on 0.5-1 kpc scales emerging from the disk. The diffuse emission is best modeled in the radial direction as a disk of constant emission measure with a sharp cutoff. Long-slit spectroscopy of the Halpha line within 2.4 kpc of the galaxy's plane shows departures from the velocity structure found in a model with strict corotation. The departures from corotation range up to 40 km s-1, consistent with galactic fountain theory. C1 CALTECH,JET PROPULS LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91125. RP PILDIS, RA (reprint author), UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109, USA. NR 19 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 190 EP 195 DI 10.1086/173798 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200015 ER PT J AU CARRAL, P HOLLENBACH, DJ LORD, SD COLGAN, SWJ HAAS, MR RUBIN, RH ERICKSON, EF AF CARRAL, P HOLLENBACH, DJ LORD, SD COLGAN, SWJ HAAS, MR RUBIN, RH ERICKSON, EF TI THE INTERSTELLAR-MEDIUM IN THE STARBURST REGIONS OF NGC-253 AND NGC-3256 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ABUNDANCES; GALAXIES, INDIVIDUAL (NGC-253, NGC-3256); GALAXIES, ISM; GALAXIES, STARBURST; INFRARED, GALAXIES ID H-II REGIONS; MOLECULAR-HYDROGEN GAS; FAR-INFRARED LINE; PHOTODISSOCIATION REGIONS; STAR FORMATION; CONTINUUM OBSERVATIONS; NEARBY GALAXIES; IRAS GALAXIES; ULTRAVIOLET-RADIATION; ABUNDANCE GRADIENTS AB We discuss observations of the [C II] 158 mum, [O I] 63 pm, [Si II] 35 mum, [O III] 52,88 mum, and [S III] 33 mum fine-structure transitions toward the central 45'' of the starburst galaxies NGC 253 and NGC 3256. The [C II] and [O I] emission probably originates in photodissociated gas at the surfaces of molecular clouds, although a small (less than or similar to 30%) contribution to the [C II] flux from H II regions cannot be ruled out. The [O III] and [S III] lines originate in H II regions and the [Si II] flux is best explained as originating in H II regions with some contribution from photodissociation regions (PDRs). The gas phase silicon abundance is nearly solar in NGC 253, which we interpret as evidence for grain destruction in the starburst region. We find that the photodissociated atomic gas has densities approximately 10(4) cm-3 and temperatures 200-300 K. About 2% of the gas is in this phase. The thermal gas pressure in the PDRs, P(PDR)/k approximately 1-3 x 10(6) K cm-3, might represent the ''typical'' interstellar gas pressure in starburst systems. The FUV radiation fields illuminating the clouds are 10(3)-10(4) stronger than the local Galactic FUV field and come from the contribution of many closely packed 0 and B stars. For the central 250 pc of NGC 253, we find that the H II gas has an average density n(e) approximately 400 cm-3. This corresponds to a thermal pressure P(H II)/k approximately 7 x 10(6) K cm-3 which is approximately P(PDR)//k, suggesting that the ionized gas is in pressure equilibrium with the photodissociated gas at the surfaces of molecular clouds. The H II gas fills a significant fraction, approximately 0.01-0.3, of the volume between the clouds. The effective temperature of the ionizing stars in NGC 253 is greater than or similar to 34,500 K; 2 x 10(5) 07.5 stars would produce the observed Lyman continuum photon luminosity. The average separation between the stars is approximately 3 pc. Applying the simple model for the interstellar medium in galactic nuclei of Wolfire, Tielens, & Hollenbach (1990), we find the molecular gas in the central regions of NGC 253 and NGC 3256 to be distributed in a large number (5 x 10(3)-5 x 10(5)) of small (0.5-2 pc), dense (approximately 10(4) CM-3) clouds (or alternatively ''thin-flattened'' structures) with volume filling factors 10(-3) 10(-2), very different from the local ISM of the Galaxy. We suggest a self-consistent scenario for the ISM in NGC 253 in which clouds and H II gas are in pressure balance with a supernova-shocked, hot 1-3 x 10(6) K, low-density (approximately 1 cm-3), all pervasive medium. A feedback mechanism may be indicated in which the pressure generated by the supernovae compresses the molecular clouds and triggers further massive star formation. The similarity of ISM parameters deduced for NGC 253, NGC 3256, and M82 (Lord et al. 1993) suggests that the ISM properties are independent of the luminosity of the starburst or the triggering mechanism (presumably a bar in NGC 253, tidal interaction in M82, and a merger in NGC 3256), but are rather endemic to starburst systems. The starburst in NGC 3256 appears to be a scaled-up version of the NGC 253 and M82 starbursts. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RI Colgan, Sean/M-4742-2014 NR 96 TC 95 Z9 95 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 223 EP 236 DI 10.1086/173801 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200018 ER PT J AU PARISE, RA MARAN, SP LANDSMAN, WB BOHLIN, RC CHENG, KP GREASON, MR HINTZEN, PMN OCONNELL, RW ROBERTS, MS SMITH, AM STECHER, TP AF PARISE, RA MARAN, SP LANDSMAN, WB BOHLIN, RC CHENG, KP GREASON, MR HINTZEN, PMN OCONNELL, RW ROBERTS, MS SMITH, AM STECHER, TP TI AN ULTRAVIOLET-VISIBLE INVESTIGATION OF THE GLOBULAR-CLUSTER NGC-1851 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GLOBULAR CLUSTERS, INDIVIDUAL (NGC-1851); HERTZSPRUNG-RUSSELL (HR) DIAGRAM; STARS, AGB AND POST-AGB; STARS, HORIZONTAL BRANCH; ULTRAVIOLET, STARS ID HORIZONTAL-BRANCH STARS; X-RAY SOURCES; EVOLUTIONARY SEQUENCES; IMAGING TELESCOPE; GIANT; PHOTOMETRY; NGC-1904; GALAXIES; SYSTEM; MASS AB Two-color ultraviolet images of the globular cluster NGC 1851 were obtained with the Ultraviolet Imaging Telescope (UIT) during the 1990 December Astro-1 Spacelab mission. A total of 133 stars are detected at 2490 angstrom and 74 stars at 1520 angstrom. An ultraviolet color-magnitude diagram based on the 46 well-photometered stars that appear in both images is presented. Thirty-nine of the 45 horizontal branch (HB) stars fall below the zero-age horizontal branch (ZAHB) of Z = 0.001 and Y = 0.23 predicted by Sweigart by as much as 0.6 mag if the interstellar reddening to the cluster is E(B - V) = 0.02. Supporting ground-based V and B observations, however, show excellent correlation with the same model ZAHB. A newly detected hot subdwarf star with T(eff) approximately 26,000 K appears to be an extreme horizontal branch star. The measured flux for this star also falls approximately 0.6 mag below the position on the CMD predicted by parameters derived from ground-based spectroscopy by Landsman. The far-ultraviolet image is dominated by the ultraviolet-bright member star UV 5, which contributes 30% of the total flux at 1520 angstrom. The UIT photometry is consistent with the classification of UV 5 as a post-asymptotic giant branch (PAGB) star. To a limit of 16.5 mag at 1520 angstrom we find no ultraviolet counterpart within 6'' of the position of the X-ray source MX 0513 - 40. C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,GREENBELT,MD 20771. NATL RADIO ASTRON OBSERV,CHARLOTTESVILLE,VA 22903. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV VIRGINIA,DEPT ASTRON,CHARLOTTESVILLE,VA 22903. RP PARISE, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,CODE 6849,GREENBELT,MD 20771, USA. NR 33 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 305 EP 309 DI 10.1086/173807 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200024 ER PT J AU HO, PTP TEREBEY, S TURNER, JL AF HO, PTP TEREBEY, S TURNER, JL TI THE ROTATING MOLECULAR CORE IN G10.6-0.4 - SYNTHESIS MAPS IN (CO)-C-12-O-18 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, INDIVIDUAL (G10.6-0.4); ISM, KINEMATICS AND DYNAMICS; ISM, MOLECULES ID STAR-FORMING REGION; H-II REGIONS; GRAVITATIONAL COLLAPSE; OB CLUSTERS; CLOUD AB Using the Owens Valley Radio Observatory millimeter-wave interferometer, the compact molecular cloud core surrounding the H II region G10.60-0.4 has been resolved in the (CO)-O-18 J = 1-0 transition. Since this line is most likely optically thin, it is an excellent tracer of the total column density. We find a centrally condensed and flattened (12''6 x 4''2; 0.3 pc x 0.1 pc) core, which is rotating rapidly with a substantial velocity gradient (17 +/- 2 km s-1 pc-1) along the major axis. The core is quite bright (> 10 K), dense (> 10(6) cm-3), massive (10(3) M.), and embedded in a more extended (>60'') envelope. There is no evidence for absorption, implying that the (CO)-O-18 emitting gas is both optically thin and substantially hotter than the equivalent continuum temperature at 3 mm. The systemic velocity of the rotating core is - 2.5 +/-0.5 km s-1, the same as the systemic velocity of the extended cloud. C1 CALTECH,PASADENA,CA 91125. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. IPAC 10022,JET PROPULS LAB,PASADENA,CA 91125. RP HO, PTP (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 12 TC 20 Z9 20 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 320 EP 325 DI 10.1086/173809 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200026 ER PT J AU BREGMAN, J LARSON, K RANK, D TEMI, P AF BREGMAN, J LARSON, K RANK, D TEMI, P TI SPECTRAL IMAGING OF THE ORION BAR AT 3.3, 8.4, AND 11.3 MICRONS - COMPARISON WITH A FLUORESCENT POLYCYCLIC AROMATIC HYDROCARBON MODEL SO ASTROPHYSICAL JOURNAL LA English DT Article DE DUST, EXTINCTION; INFRARED, ISM, CONTINUUM; ISM, INDIVIDUAL (ORION NEBULA); ISM, MOLECULES ID INFRARED-EMISSION BANDS; IONIZATION FRONT REGION; FEATURES; NEBULA; CARBON; DUST AB Spectral images were obtained of the Orion Bar which sample polycyclic aromatic hydrocarbon (PAH) emission at 3.3, 8.4, and 11.3 mum. The images are strikingly different even though they all sample PAH emission. In particular, the 3.3 and 11.3 mum images sample PAH emission from C-H bonds, yet the 3.3 mum image contains many small bright knots while the 11.3 mum image is much more uniform. For comparison with a fluorescent PAH model, a data set was created from the measured intensities of 250 locations in each image. From the comparison, we conclude that: (1) the size distribution of PAHs varies within the Bar, with the bright 3.3 mum knots containing the largest proportion of small PAHs; (2) the points along the front of the Bar have emission cross sections characteristic of neutral PAHs while within the Bar, the emission cross sections are different, consistent with the PAHs being charged; (3) the PAHs along the front of the Bar are larger than average for the Bar, (4) emission along the back of the Bar is consistent with PAH emission in an attenuated UV radiation field; (5) there is no evidence for PAH dehydrogenation. C1 UCSC,UCO & LICK OBSERV,SANTA CRUZ,CA 95064. RP BREGMAN, J (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 254-6,MOFFETT FIELD,CA 94035, USA. NR 16 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 326 EP 333 DI 10.1086/173810 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200027 ER PT J AU NEMIROFF, RJ NORRIS, JP KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS AF NEMIROFF, RJ NORRIS, JP KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS TI GAMMA-RAY BURSTS ARE TIME-ASYMMETRIC SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, BURSTS AB A simple test for time asymmetry is devised and carried out on the brightest gamma-ray bursts (GRBs) detected by the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory. We show evidence that individual bursts are time-asymmetric on all timescales tested, from a timescale shorter than that of pulses which compose GRBs to a timescale similar to a greater envelope that contains these pulses. We also find bursts which manifest significant asymmetry only on timescales comparable to the duration of burst, and bursts for which no clear asymmetry on any timescale is present. The sense of the asymmetry is that bursts and/or component structures rise in a shorter time than they decay. We also find that our whole sample of bursts taken together is time-asymmetric, in that there are significantly more bursts and pulses where the rise is more rapid than the decay, on all timescales tested and for all energy bands tested. When our whole GRB sample is binned at 64 ms and integrated over all BATSE energies, the statistical significance is at the 6 sigma level. Models that predict time symmetry are therefore excluded. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. GEORGE MASON UNIV,FAIRFAX,VA 22030. UNIV ALABAMA,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP NEMIROFF, RJ (reprint author), UNIV SPACE RES ASSOC,WASHINGTON,DC, USA. NR 22 TC 45 Z9 47 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 432 EP 435 DI 10.1086/173819 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200036 ER PT J AU MICHALITSIANOS, AG PEREZ, M KAFATOS, M AF MICHALITSIANOS, AG PEREZ, M KAFATOS, M TI EVIDENCE SIGNALING THE START OF ENHANCED COUNTERJET FLOW IN THE SYMBIOTIC SYSTEM R-AQUARII SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, SYMBIOTIC; CIRCUMSTELLAR MATTER; STARS, INDIVIDUAL (R-AQUARII); STARS, MASS LOSS ID RADIO; CONTINUUM; NEBULA AB The velocity structure of strong far-UV emission lines observed in the symbiotic variable R Aqr suggests the start of new jet activity which will probably culminate in the appearance of a series of intense nebular emission knots within a decade. This is indicated by a systematic redward wavelength drift of emission lines, which we have followed with the International Ultraviolet Explorer (IUE) since the discovery of the brilliant north-east jet emission knots more than 10 years ago. The C IV lambdalmabda1548, 1550 resonance lines, which previously showed a prominent blue asymmetric wing that extended to velocities in excess -200 km s-1, exhibit red wing asymmetry that extends to speeds of approximately +200 km s-1 in late 1992. The C IV line profile structure is consistent with the model proposed by Solf (1993), who explains the appearance of the northeast jet knots in terms of a approximately 300-500 km s-1 collimated wind that collides with slower moving material expelled earlier in a nova outburst that occurred approximately 190 yr ago. Based upon these high-resolution UV spectra, similar emission structures should appear southwest of the central star when the counterwind (or stream) interacts with material in the southwest inner nebula. The apparent change in direction of flow could result from a precessing accretion disk that alters the projection angle of collimated flow from the disk poles. The direction of the collimated wind may be related to the binary orbit, because the velocity shifts associated with emission lines formed in the flow change direction on a timescale which is comparable to the binary period. C1 NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,IUE OBSERV,GREENBELT,MD 20771. GEORGE MASON UNIV,INST COMPUTAT SCI & INFORMAT,FAIRFAX,VA 22030. GEORGE MASON UNIV,DEPT PHYS,FAIRFAX,VA 22030. RP MICHALITSIANOS, AG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 684,GREENBELT,MD 20771, USA. NR 16 TC 4 Z9 4 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP 441 EP 445 DI 10.1086/173821 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ152 UT WOS:A1994MZ15200038 ER PT J AU LEONARD, PJT HILLS, JG DEWEY, RJ AF LEONARD, PJT HILLS, JG DEWEY, RJ TI A NEW WAY TO MAKE THORNE-ZYTKOW OBJECTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, GENERAL; STARS, NEUTRON; SUPERGIANTS; SUPERNOVAE, GENERAL ID DEGENERATE NEUTRON CORES; X-RAY BINARIES; YOUNG STAR-CLUSTERS; RUNAWAY STARS; INITIAL BINARIES; MASS; EVOLUTION; PULSARS; ORIGIN; EXPLOSION AB We have found a new way to make Thorne-Zytkow objects, which are massive stars with degenerate neutron cores. The asymmetric kick given to the neutron star.formed when the primary of a massive tight binary system explodes as a supernova sometimes has the appropriate direction and amplitude to place the newly formed neutron star into a bound orbit with a pericenter distance smaller than the radius of the secondary. Consequently, the neutron star becomes embedded in the secondary. Thorne-Zytkow objects are expected to look like extreme M-type supergiants, assuming that they can avoid a runaway neutrino instability. Accretion onto the embedded neutron star will produce either an isolated, spun-up neutron star (possibly a short-period pulsar) or a black hole. Whether neutron star or black hole remnants predominate depends on the lifetime of Thorne-Zytkow objects, the accretion rates involved, and the maximum neutron star mass, none of which are definitively understood. C1 JET PROP LAB,PASADENA,CA 91109. RP LEONARD, PJT (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 49 TC 16 Z9 16 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP L19 EP L22 DI 10.1086/187225 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ155 UT WOS:A1994MZ15500005 ER PT J AU SALAMON, MH STECKER, FW DEJAGER, OC AF SALAMON, MH STECKER, FW DEJAGER, OC TI A NEW METHOD FOR DETERMINING THE HUBBLE CONSTANT FROM SUB-TEV GAMMA-RAY OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE DISTANCE SCALE; GAMMA RAYS, THEORY; INFRARED, GENERAL; QUASARS, GENERAL; QUASARS, INDIVIDUAL (1633 + 382) ID COSMOLOGY; PARAMETER AB The present uncertainty in the Hubble constant leaves unresolved questions regarding the age of the universe and related matters involving the amount and nature of the dark matter in the universe, consistency with the inflationary model of the universe, and the need for a cosmological constant. It is clear that a significantly precise determination of the Hubble constant by as many different methods as possible is crucial to our knowledge and understanding of the character of the universe. We propose here an entirely new method for determining the Hubble constant, based on measuring the extinction of high-energy gamma-rays emitted by detectable gamma-ray emitting blazars at various redshifts. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. POTCHEFSTROOM UNIV CHRISTIAN HIGHER EDUC,DEPT PHYS,SPACE RES UNIT,POTCHEFSTROOM 2520,SOUTH AFRICA. RP SALAMON, MH (reprint author), UNIV UTAH,DEPT PHYS,INST HIGH ENERGY ASTROPHYS,SALT LAKE CITY,UT 84112, USA. RI Stecker, Floyd/D-3169-2012 NR 33 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1994 VL 423 IS 1 BP L1 EP L4 DI 10.1086/187221 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ155 UT WOS:A1994MZ15500001 ER PT J AU THOMAS, RJ NEUPERT, WM AF THOMAS, RJ NEUPERT, WM TI EXTREME-ULTRAVIOLET SPECTRUM OF A SOLAR ACTIVE-REGION FROM SERTS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE SUN, ACTIVITY; SUN, UV RADIATION ID PHOTOIONIZATION CROSS-SECTIONS; FE-XIV; THRESHOLD; IDENTIFICATIONS; IONIZATION; ANGSTROMS; LINES AB We present wavelengths and absolute intensities for 243 emission lines from a single active region observed by the Solar EUV Rocket Telescope and Spectrograph (SERTS) on 1989 May 5. For this catalog, the imaged spectra have been spatially averaged over a field of view 7'' X 276'' cutting through the center of AR5464 at S18 W45. Wavelength coverage is 170-450 angstrom with a spectral resolution approaching 10,000. Most of the line positions are determined to 5 mangstrom or better, representing the highest accuracy yet obtained for solar wavelengths throughout this spectral interval. The relative photometric calibration of the instrument is good to +/-20% over its first-order range, and has been placed onto an absolute scale that should be correct to within a factor less than 2. Where known, identifications, atomic transitions and formation temperatures are also given. The identified lines arise from temperatures that cover the range 4.7 less-than-or-equal-to log T less-than-or-equal-to 6.8, providing information about the Sun's corona and upper transition region. Upper limits to the intensity of any emission line not included here can be estimated from the measured instrumental sensitivity. This averaged EUV spectrum should prove useful as a source of accurate wavelengths and intensities for emission characteristic of the high-temperature plasma associated with a solar active region and small subflare. RP THOMAS, RJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 680,GREENBELT,MD 20771, USA. NR 35 TC 222 Z9 223 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 1994 VL 91 IS 1 BP 461 EP 482 DI 10.1086/191944 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ319 UT WOS:A1994MZ31900008 ER PT J AU GOORVITCH, D CHACKERIAN, C AF GOORVITCH, D CHACKERIAN, C TI CALCULATION OF (CO)-C-12-O-16 AND (CO)-C-13-O-16 X(1)SIGMA+ ROVIBRATIONAL INTENSITIES FOR UPSILON-LESS-THAN-OR-EQUAL-TO-20 AND J-LESS-THAN-OR-EQUAL-TO-150 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE MOLECULAR DATA ID DIATOMIC-MOLECULES; CO AB Improved electric dipole transition matrix elements for rovibrational transitions in the ground state X1SIGMA+ of (CO)-C-12-O-16 and (CO)-C-13-O-16 are calculated for all the DELTAv = +1, +2, and +3 transitions for which v less-than-or-equal-to 20 and J less-than-or-equal-to 150. We have fitted polynomials to these matrix elements as a function of the parameter m which is defined in terms of the lower state angular momentum quantum number J. These convenient to use polynomial representations are given in Tables 1-4 for (CO)-C-12-O-16 and in Tables 5-8 for (CO)-C-13-O-16. We observe that there is intensity enhancement due to vibration-rotation interaction for the P-branch transitions at the expense of the R-branch transitions for DELTAv = +1. This enhancement can be as large as 40% at the highest J, For the DELTAv = +2 and +3 transitions, the R-branch transitions are enhanced by as much as a factor of 2.75 and 10 at the highest J, respectively. The P-branch transitions exhibit only minor decreases. Comparisons with previous calculations show good agreement for the DELTAv = +1 transitions. The comparison for DELTAv = +2 and +3 transitions show differences as large as a factor of 5. C1 NASA,AMES RES CTR,DIV EARTH SYST SCI,MOFFETT FIELD,CA 94035. RP GOORVITCH, D (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS N245-6,MOFFETT FIELD,CA 94035, USA. NR 11 TC 80 Z9 80 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 1994 VL 91 IS 1 BP 483 EP 489 DI 10.1086/191945 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ319 UT WOS:A1994MZ31900009 ER PT J AU VANDEMARK, D JACKSON, FC WALSH, EJ CHAPRON, B AF VANDEMARK, D JACKSON, FC WALSH, EJ CHAPRON, B TI AIRBORNE RADAR MEASUREMENTS OF OCEAN WAVE SPECTRA AND WIND-SPEED DURING THE GRAND-BANKS ERS-1 SAR WAVE EXPERIMENT SO ATMOSPHERE-OCEAN LA English DT Article ID SYNTHETIC APERTURE RADAR; SURFACE CONTOUR RADAR; DIRECTIONAL SPECTRA; SIR-B; AIRCRAFT AB Measurements of ocean directional wave spectra, significant wave height, and wind speed over the Grand Banks of Newfoundland were made using the combined capabilities of the radar ocean wave spectrometer (ROWS) and scanning radar altimeter (SRA). The instruments were flown aboard the NASA P-3A aircraft in support of the Grand Banks ERS-1 Synthetic Aperture Radar (SAR) Wave Experiment. The NASA sensors use proven techniques, which differ greatly from SAR, for estimating the directional long-wave spectrum; thus they provide a unique set of measurements for use in evaluating SAR performance. ROWS and SRA data are combined with spectra from the SAR aboard the Canadian Centre for Remote Sensing (CCRS) CV-580 aircraft, the first-generation Canadian Spectral Ocean Wave Model (csowM) hindcast, and other available in situ measurements to assess the ERS-1 SAR's ability to correctly resolve wave field components along a 200- to 300-km flight line for four separate satellite passes. Given the complex seas present on the Grand Banks, the complementary nature of viewing the sea spectrum from the perspectives of multiple sensors and a wave prediction model is apparent. The data intercomparisons show the ERS-1 SAR to be meeting the expected goals for measuring swell, but the data also show evidence of this remote sensor's inability to detect the shorter waves travelling in the azimuth or along-track direction. Example SAR spectra simulations are made using a non-linear forward transform with ROWS measurements as input. Additionally, surface wind and wave height estimates made using the ROWS altimeter channel are presented. These data demonstrate the utility of operating the system in its new combined altimeter and spectrometer configuration. C1 IFREMER, CTR BREST, F-29280 PLOUZANE, FRANCE. RP NASA, GODDARD SPACE FLIGHT CTR, HYDROSPHER PROC LAB, WALLOPS ISL, VA 23337 USA. RI Chapron, Bertrand/O-6527-2015 NR 34 TC 11 Z9 11 U1 0 U2 2 PU CMOS-SCMO PI OTTAWA PA BOX 3211, STATION D, OTTAWA, ON K1P 6H7, CANADA SN 0705-5900 EI 1480-9214 J9 ATMOS OCEAN JI Atmos.-Ocean PD MAR PY 1994 VL 32 IS 1 BP 143 EP 178 PG 36 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA NK998 UT WOS:A1994NK99800007 ER PT J AU CHAPRON, B VANDEMARK, D JACKSON, FC AF CHAPRON, B VANDEMARK, D JACKSON, FC TI AIRBORNE MEASUREMENTS OF THE OCEANS K(U)-BAND RADAR CROSS-SECTION AT LOW INCIDENCE ANGLES SO ATMOSPHERE-OCEAN LA English DT Article ID SURFACE SCATTERING; WAVE SPECTROMETER; SPECTRA AB Ocean backscatter data obtained with a K(u)-band airborne radar are presented along with coincident altimeter and directional wave spectral estimates. These data were collected using one sensor, NASA's radar ocean wave spectrometer (ROWS). The measurements are compared with an electromagnetic scattering model for perfectly conducting Gaussian random surfaces. The normalized radar cross-section (NRCS) data cover those incidence angles (0-20-degrees) where both quasi-specular and Bragg scattering mechanisms are expected. Under certain conditions, identification and separation of these two mechanisms is possible. The scanning radar allows observations of the azimuthal variations in NRCS that are at times indicative of short-scale wave generation in the wind direction. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,WALLOPS ISL,VA 23337. RP CHAPRON, B (reprint author), IFREMER,CTR BREST,DRO OS BP 70,F-29280 PLOUZANE,FRANCE. RI Chapron, Bertrand/O-6527-2015 NR 19 TC 4 Z9 4 U1 0 U2 2 PU CANADIAN METEOROLOGICAL OCEANOGRAPHIC SOC PI OTTAWA PA 150 LOUIS PASTEUR PVT., STE 112, MCDONALD BUILDING, OTTAWA ON K1N 6N5, CANADA SN 0705-5900 J9 ATMOS OCEAN JI Atmos.-Ocean PD MAR PY 1994 VL 32 IS 1 BP 179 EP 193 PG 15 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA NK998 UT WOS:A1994NK99800008 ER PT J AU PUESCHEL, RF LIVINGSTON, JM FERRY, GV DEFELICE, TE AF PUESCHEL, RF LIVINGSTON, JM FERRY, GV DEFELICE, TE TI AEROSOL ABUNDANCES AND OPTICAL CHARACTERISTICS IN THE PACIFIC BASIN FREE TROPOSPHERE SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT Conference on Visibility and Fine Particles CY SEP 15-18, 1992 CL VIENNA, AUSTRIA DE ATMOSPHERIC AEROSOLS; BACKGROUND CONCENTRATION; OPTICAL PROPERTIES ID CLIMATE AB During NASA's Global Backscatter Experiment (GLOBE) mission flights in November 1989 and May 1990, a DC-8 research aircraft probed the Pacific Basin free troposphere for about 90 flight hours in each month between +72 and -62 degrees latitude, +130 and -120 degrees longitude, and up to 39,000 feet pressure altitudes. Aerosols were sampled continuously in situ by optical particle counters to measure concentration and particle size, and during 48 10-min intervals during each mission by wire impactors for concentration, size, composition, phase and shape analyses. The optical particle counters cover a particle diameter range between 0.3 and 20 mum; wire impactors extend the range down to 0.03 mum. Results of particle number, size, shape, together with the assumption of a refractive index corresponding to (NH4)2SO4 to account for the prevalence of aerosol sulfur, were utilized in a Mie algorithm to calculate aerosol extinction and backscatter for a range of wavelengths (0.385 < lambda < 10.64 mum). Computations for 22 randomly selected size distributions yield coefficients of extinction E0.525 = (2.03 +/- 1.20) x 10(-4) km-1 and backscatter beta0.525 = (6.45 +/- 3.49) x 10(-6) km-1 sr-1 in the visible, and E10.64 = (8.13 +/- 6.47) x 10(-6) km-1 and beta10.64 = (9.98 +/- 10.69) x 10(-8) km-1 sr-1 in the infra-red, respectively. Large particles (D > 0.3 mum) contribute two-thirds to the total extinction in the visible (lambda = 0.525 mum), and almost 100% in the infra-red (lambda = 10.64 mum). These results have been used to define an IR optical aerosol climatology of the Pacific Basin free troposphere, from which it follows that the infra-red backscatter coefficient at lambda = 9.25 mum wavelength fluctuates between 5.0 x 10(-10) and 2.0 x 10(-7) km-1 sr-1 with a modal value 2.0 x 10(-8) km-1 sr-1. C1 SRI INT,MENLO PK,CA 94025. UNIV WISCONSIN,MILWAUKEE,WI 53201. RP PUESCHEL, RF (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 10 TC 37 Z9 37 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAR PY 1994 VL 28 IS 5 BP 951 EP 960 DI 10.1016/1352-2310(94)90253-4 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA NR215 UT WOS:A1994NR21500022 ER PT J AU OBERBECK, VR MANCINELLI, RL AF OBERBECK, VR MANCINELLI, RL TI ASTEROID IMPACTS, MICROBES, AND THE COOLING OF THE ATMOSPHERE SO BIOSCIENCE LA English DT Article ID CHEMICAL EVOLUTION; EARLY EARTH; LIFE; CHERTS; ORIGIN C1 SETI INST,MT VIEW,CA 94043. RP OBERBECK, VR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Mancinelli, Rocco/L-8971-2016 NR 34 TC 5 Z9 5 U1 1 U2 1 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD MAR PY 1994 VL 44 IS 3 BP 173 EP 177 DI 10.2307/1312254 PG 5 WC Biology SC Life Sciences & Biomedicine - Other Topics GA MY533 UT WOS:A1994MY53300014 PM 11539596 ER PT J AU PENNER, JE CHARLSON, RJ HALES, JM LAULAINEN, NS LEIFER, R NOVAKOV, T OGREN, J RADKE, LF SCHWARTZ, SE TRAVIS, L AF PENNER, JE CHARLSON, RJ HALES, JM LAULAINEN, NS LEIFER, R NOVAKOV, T OGREN, J RADKE, LF SCHWARTZ, SE TRAVIS, L TI QUANTIFYING AND MINIMIZING UNCERTAINTY OF CLIMATE FORCING BY ANTHROPOGENIC AEROSOLS SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CLOUD-CONDENSATION-NUCLEI; LONG-RANGE TRANSPORT; SULFATE AEROSOL; ATMOSPHERIC SULFUR; OPTICAL-PROPERTIES; RADIATIVE-TRANSFER; MARINE ATMOSPHERE; ORGANIC AEROSOLS; SOLAR-RADIATION; ARCTIC HAZE AB Anthropogenic aerosols are composed of a variety of aerosol types and components including water-soluble inorganic species (e.g., sulfate, nitrate, ammonium), condensed organic species, elemental or black carbon, and mineral dust. Previous estimates of the clear sky forcing by anthropogenic sulfate aerosols and by organic biomass-burning aerosols indicate that this forcing is of sufficient magnitude to mask the effects of anthropogenic greenhouse gases over large regions. Here, the uncertainty in the forcing by these aerosol types is estimated. The clear sky forcing by other anthropogenic aerosol components cannot be estimated with confidence, although the forcing by these aerosol types appears to be smaller than that by sulfate and biomass-burning aerosols. The cloudy sky forcing by anthropogenic aerosols, wherein aerosol cloud condensation nuclei concentrations are increased, thereby increasing cloud droplet concentrations and cloud albedo and possibly influencing cloud persistence, may also be significant. in contrast to the situation with the clear sky forcing, estimates of the cloudy sky forcing by anthropogenic aerosols are little more than guesses, and it is not possible to quantity the uncertainty of the estimates. In view of present concerns over greenhouse gas-induced climate change, this situation dictates the need to quantify the forcing by anthropogenic aerosols and to define and minimize uncertainties in the calculated forcings. In this article, a research strategy for improving the estimates of the clear sky forcing is defined. The strategy encompasses five major, and necessarily coordinated, activities: surface-based observations of aerosol chemical and physical properties and their influence on the radiation field; aircraft-based observations of the same properties; process studies to refine model treatments; satellite observations of aerosol abundance and size distribution; and modeling studies to demonstrate consistency between the observations, to provide guidance for determination of the most important parameters, and to allow extension of the limited set of observations to the global scale. Such a strategy, if aggressively implemented, should allow these effects to be incorporated into climate models in the next several years. A similar strategy for defining the magnitude of the cloudy sky forcing should also be possible, but the less firm understanding of this forcing suggests that research of a more exploratory nature be carried out before undertaking a research strategy of the magnitude recommended for the clear sky forcing. C1 UNIV WASHINGTON, SEATTLE, WA 98195 USA. ENVAIR, RICHLAND, WA USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. ENVIRONM MEASUREMENTS LAB, NEW YORK, NY USA. LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP PENNER, JE (reprint author), LAWRENCE LIVERMORE NATL LAB, POB 808, L-262, LIVERMORE, CA 94550 USA. RI Schwartz, Stephen/C-2729-2008; Penner, Joyce/J-1719-2012 OI Schwartz, Stephen/0000-0001-6288-310X; NR 92 TC 276 Z9 280 U1 5 U2 42 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 1994 VL 75 IS 3 BP 375 EP 400 DI 10.1175/1520-0477(1994)075<0375:QAMUOC>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NC607 UT WOS:A1994NC60700003 ER PT J AU GUYETTE, L HAMIDIAN, K TUAZON, JO AF GUYETTE, L HAMIDIAN, K TUAZON, JO TI A RULE-BASED EXPERT-SYSTEM APPROACH TO CLASS SCHEDULING SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article AB Class scheduling is the unenviable task in which a team of scheduling experts must assign faculty members their requested courses based on the university and departmental guidelines. The complexity of this task is compounded by introducing the various necessary faculty and course parameters. Although there have been recent attempts to create the class scheduling process via conventional programming, this form of software is poorly suited to emulate the essential human decision-making process. However, a rule-based expert system approach can provide the practical solution. This paper is concerned with originating the formulation and implementation necessary to achieve an optimal class scheduling solution. C1 CALIF STATE UNIV FULLERTON,DEPT ELECT ENGN,FULLERTON,CA 92634. CALTECH,JET PROP LAB,PASADENA,CA. NR 9 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 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PD MAR PY 1994 VL 20 IS 2 BP 151 EP 162 DI 10.1016/0045-7906(94)90027-2 PG 12 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA MX251 UT WOS:A1994MX25100006 ER PT J AU TAKEDA, H MORI, H BOGARD, DD AF TAKEDA, H MORI, H BOGARD, DD TI MINERALOGY AND AR-39-AR-40 AGE OF AN OLD PRISTINE BASALT - THERMAL HISTORY OF THE HED PARENT BODY SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article ID EUCRITE; ACHONDRITES AB Previous investigations of mineral chemistry and Rb-Sr and Sm-Nd ages indicated that clast,84 from eucrite Yamato 75011 had preserved the pristine nature of its initial crystallization during an early stage of the HED parent body. Microscale mineralogy and Ar-39-Ar-40 ages of this clast, however, revealed local disturbance of microtextures and partially reset ages. This evidence suggests that, in addition to initial crystallization and rapid cooling, the Y75011,84 clast experienced shock deformation, reheating of short duration at higher temperature, and brecciation. These characteristics suggest two or more impact events. Fe-rich olivine filling fractures in pyroxene may have been introduced during the accompanying shock fracturing. The inferred Ar-40-Ar-39 degassing ages for Y75011 matrix and clast,84 are 3.94 +/- 0.04 Ga and 3.98 +/- 0.03 Ga, respectively. The suggested degassing age for a clast from Y790020, believed to be paired with Y75011, is approximately 4.03 Ga, but could be younger. We consider it likely that all three samples experienced a common degassing event 3.95 +/- 0.05 Ga ago, but we cannot rule out two or more events spaced over a approximately 0.1 Ga interval. Higher temperature extractions of the two clast samples show significantly older apparent ages up to approximately 4.5 Ga and suggest that the time/temperature regime of this event was not sufficient to degas Ar totally. Most likely, the K-Ar ages were reset by thermal metamorphism associated with one or more impact events associated with shock fracturing, formation of Fe-rich olivine veins, and/or meteorite brecciation. The pyroxene annealing that commonly occurs in many eucrites is likely to be a much earlier process than the impact-produced textural changes and reset K-Ar ages observed in these meteorites. The existence of mineralogical and chronological evidence for metamorphism in an otherwise pristine eucrite suggests that the HED parent body experienced an extensive degree of early cratering. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP TAKEDA, H (reprint author), UNIV TOKYO,FAC SCI,INST MINERAL,TOKYO 113,JAPAN. NR 28 TC 29 Z9 30 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD MAR PY 1994 VL 122 IS 1-2 BP 183 EP 194 DI 10.1016/0012-821X(94)90059-0 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA NE757 UT WOS:A1994NE75700013 ER PT J AU DAVIS, MW OLLA, BL AF DAVIS, MW OLLA, BL TI ONTOGENIC SHIFT IN GEOTAXIS FOR WALLEYE POLLOCK, THERAGRA-CHALCOGRAMMA FREE EMBRYOS AND LARVAE - POTENTIAL ROLE IN CONTROLLING VERTICAL-DISTRIBUTION SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Note DE BEHAVIOR; BUOYANCY; ORIENTATION; RESTING; SWIMMING; YOLKSAC LARVAE ID LIGHT; RESPONSES AB The behavioral capability of walleye pollock, Theragra chalcogramma free embryos and larvae to control vertical distribution was assessed by examining buoyancy during resting and swimming orientation and activity as they developed in complete darkness from hatching to first feeding readiness (1 to 7 d post hatching at 6-degrees-C). Free embryos exhibited positive geotaxis 1 d post hatching, actively swimming through a density gradient to remain in the lower water column. Activity increased with free embryo development and by 7 d post hatching, feeding-ready larvae reversed their vertical orientation, now exhibiting negative geotaxis as they migrated to the upper water column. The results indicate that even at the earliest developmental stages, walleye pollock possess the capability to control vertical distribution. Laboratory results are compared with patterns of vertical distribution observed in the sea. RP DAVIS, MW (reprint author), NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,HATFIELD MARINE SCI CTR,NEWPORT,OR 97365, USA. NR 18 TC 11 Z9 11 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAR PY 1994 VL 39 IS 3 BP 313 EP 318 DI 10.1007/BF00005132 PG 6 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA NA684 UT WOS:A1994NA68400009 ER PT J AU RIGGAN, PJ LOCKWOOD, RN JACKS, PM COLVER, CG WEIRICH, F DEBANO, LF BRASS, JA AF RIGGAN, PJ LOCKWOOD, RN JACKS, PM COLVER, CG WEIRICH, F DEBANO, LF BRASS, JA TI EFFECTS OF FIRE SEVERITY ON NITRATE MOBILIZATION IN WATERSHEDS SUBJECT TO CHRONIC ATMOSPHERIC DEPOSITION SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID SOUTHERN-CALIFORNIA; FERTILIZATION AB Severe fires in chaparral watersheds subject to air pollution from metropolitan Los Angeles mobilized accumulated nitrogen and caused streamwater to be polluted with nitrate at concentrations exceeding the Federal Water Quality Standard. Streamwater NO3-concentrations were elevated during peak flows, the largest of which was a debris flow that transported NO3- at concentrations as high as 1.12 mequiv/L. Annual NO3- loss from severely burned watersheds, averaging 1.2 kequiv/ha,was 40 times greater than that from areas that remained unburned. Fires of moderate intensity produced a more subdued response in stream discharge and soil nitrification and less than one-seventh the NO3- loss observed after Severe burning. We infer that the combination of atmospheric deposition with severe wildfires provides a strong and recurrent source of nitrate that could contribute to existing groundwater pollution in parts of eastern Los Angeles County. Moderating the fire regime by prescribed burning could provide substantial mitigation. C1 UNIV IOWA,DEPT GEOG,IOWA CITY,IA 52242. UNIV IOWA,DEPT CIVIL & ENVIRONM ENGN,IOWA CITY,IA 52242. UNIV IOWA,IOWA HYDRAUL INST,IOWA CITY,IA 52242. US FOREST SERV,ROCKY MT RES STN,FLAGSTAFF,AZ 86001. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP RIGGAN, PJ (reprint author), US FOREST SERV,PACIFIC SW RES STN,RIVERSIDE,CA 92507, USA. NR 23 TC 55 Z9 55 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAR PY 1994 VL 28 IS 3 BP 369 EP 375 DI 10.1021/es00052a005 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA MZ607 UT WOS:A1994MZ60700012 PM 22165868 ER PT J AU SAWYER, JW ROTHGEB, TM AF SAWYER, JW ROTHGEB, TM TI AN INSTRUMENTED FASTENER FOR SHEER FORCE MEASUREMENTS IN JOINTS SO EXPERIMENTAL MECHANICS LA English DT Article AB A preliminary investigation has been conducted on instrumented fasteners for use as sensors to measure the shear loads transmitted by individual fasteners installed in double-splice joints. Calibration and load verification tests were conducted for instrumental fasteners installed at three fastener torque levels. Results from calibration tests show that the shear strains obtained from the instrumented fasteners vary linearly with the applied load and that the instrumental fasteners can be effectively used to measure shear loads transmitted by individual fasteners installed in double-splice joints. Tests were also conducted with three instrumented fasteners installed in a typical double-splice joint. The test results showed that the load distribution between individual fasteners is dependent on the location of the fastener in the joint and the fastener torque level. The fastener located near the end of the joint with the single plate carried more load the the fasteners located near the end of the joint with the two plates. Installing the fasteners with a torque greater than finger tight results in a significant amount of the load being carried by friction between the faying surfaces of the plates even if the faying surfaces are polished and lubricated. Increasing the fastener torque also results in a more uniform distribution of the loads between the individual fasteners for joints in aluminum plates with two fasteners, but does not have a significant effect for joints in steel plates with three fasteners. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23668. RP SAWYER, JW (reprint author), NASA,LANGLEY RES CTR,MS 396,HAMPTON,VA 23668, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD MAR PY 1994 VL 34 IS 1 BP 16 EP 22 DI 10.1007/BF02328437 PG 7 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA NF458 UT WOS:A1994NF45800003 ER PT J AU HO, H TSAI, MY MORTON, J FARLEY, GL AF HO, H TSAI, MY MORTON, J FARLEY, GL TI INPLANE SHEAR TESTING OF GRAPHITE-WOVEN FABRIC COMPOSITES SO EXPERIMENTAL MECHANICS LA English DT Article ID LOCALIZED HYBRID METHOD; IOSIPESCU SPECIMEN; STRESS-ANALYSIS; STRENGTH; BEHAVIOR AB The losipescu shear test method was used to determine the in-plane shear response of AS4 and Celion carbon fiber/epoxy fabric composite materials. Several weave architectures were studied: AS4 uniweave, AS4 and Celion plain weaves, Celion 5-harness and 8-harness satin weaves. Specimens were tested using traditional strain gage techniques and full-field moire interferometry. A full-node localized hybrid analysis is introduced to perform efficient reduction of moire data, producing whole-field strain distributions in the specimen test section. It was found that the fabric yam size greatly influenced the uniformity of the shear field in the specimen test section, However, consistent shear moduli still can be obtained using the modified losipescu specimen and Wyoming fixture except for fabrics with large fiber yarns. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP HO, H (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061, USA. NR 15 TC 9 Z9 9 U1 1 U2 3 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD MAR PY 1994 VL 34 IS 1 BP 45 EP 52 DI 10.1007/BF02328441 PG 8 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA NF458 UT WOS:A1994NF45800007 ER PT J AU CRANDALL, CG RAVEN, PB JOHNSON, JM ENGELKE, KA CONVERTINO, VA AF CRANDALL, CG RAVEN, PB JOHNSON, JM ENGELKE, KA CONVERTINO, VA TI ALTERED THERMOREGULATORY RESPONSES FOLLOWING 15 DAYS SIMULATED MICROGRAVITY SO FASEB JOURNAL LA English DT Meeting Abstract C1 TCOM,FT WORTH,TX 76107. UTHSCSA,SAN ANTONIO,TX 78284. NASA,KENNEDY SPACE CTR,FL 32899. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. ARMSTRONG LAB,BROOKS AFB,TX 78235. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A261 EP A261 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19601507 ER PT J AU FORTNEY, SM WATENPAUGH, DE HARGENS, AR BALLARD, RE MURTHY, G LEE, SMC BENNETT, BS FORD, SR AF FORTNEY, SM WATENPAUGH, DE HARGENS, AR BALLARD, RE MURTHY, G LEE, SMC BENNETT, BS FORD, SR TI A DAILY, 30-MINUTE BOUT OF INTERVAL TREADMILL EXERCISE WITH LOWER-BODY NEGATIVE-PRESSURE (LBNP) DOES NOT MAINTAIN EXERCISE CAPACITY DURING BED REST SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. KRUG LIFE SCI,HOUSTON,TX. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. BIONET INC,MOFFETT FIELD,CA. UNIV TEXAS,MED BRANCH,GALVESTON,TX 77550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A261 EP A261 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19601506 ER PT J AU GOSSELINK, KL GRINDELAND, RE ROY, RR MUKKU, VR TALMADGE, RJ EDGERTON, VR LINDERMAN, JK AF GOSSELINK, KL GRINDELAND, RE ROY, RR MUKKU, VR TALMADGE, RJ EDGERTON, VR LINDERMAN, JK TI EFFECTS OF GROWTH-HORMONE AND INSULIN-LIKE GROWTH-FACTOR-I WITH OR WITHOUT EXERCISE ON HYPOPHYSECTOMIZED HINDLIMB SUSPENDED RATS SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. GENENTECH INC,S SAN FRANCISCO,CA 94080. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A10 EP A10 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19600054 ER PT J AU GREENLEAF, JE KRUK, B NAZAR, K KACIUBAUSCILKO, H AF GREENLEAF, JE KRUK, B NAZAR, K KACIUBAUSCILKO, H TI BODY TEMPERATURES DURING EXERCISE IN DECONDITIONED DOGS - EFFECT OF NACL AND GLUCOSE-INFUSION SO FASEB JOURNAL LA English DT Meeting Abstract C1 POLISH ACAD SCI,PL-00730 WARSAW,POLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A64 EP A64 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19600370 ER PT J AU GROVER, RF SELLAND, M MCCULLOUGH, RG GREENLEAF, JE DAHMS, TE WOLFEL, E REEVES, JT AF GROVER, RF SELLAND, M MCCULLOUGH, RG GREENLEAF, JE DAHMS, TE WOLFEL, E REEVES, JT TI TIME-COURSE AND VARIABILITY OF POLYCYTHEMIC RESPONSE IN MEN AT HIGH-ALTITUDE SO FASEB JOURNAL LA English DT Meeting Abstract C1 UNIV COLORADO,HLTH SCI CTR,CVP RES LAB,DENVER,CO 80262. NASA,AMES RES CTR,HUMAN GRAVITAT PHYSIOL LAB,MOFFETT FIELD,CA 94035. ST LOUIS UNIV,SCH MED,DEPT ANESTHESIOL,ST LOUIS,MO 63104. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A553 EP A553 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19603202 ER PT J AU REID, MB NORFLEET, WT AF REID, MB NORFLEET, WT TI HUMAN CHEST-WALL SHAPE IN MICROGRAVITY SO FASEB JOURNAL LA English DT Meeting Abstract C1 BAYLOR COLL MED,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A539 EP A539 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19603124 ER PT J AU SICONOLFI, SF NUSYNOWITZ, ML SUIRE, SS MOORE, AD ROGERS, A AF SICONOLFI, SF NUSYNOWITZ, ML SUIRE, SS MOORE, AD ROGERS, A TI ASSESSING TOTAL BLOOD (TBV), PLASMA-VOLUME (PV), DELTA-TBV, AND DELTA-PV FROM BIOELECTRICAL RESPONSE SPECTROSCOPY (BERS) SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. UNIV TEXAS,MED BRANCH,GALVESTON,TX 77550. KRUG LIFE SCI,HOUSTON,TX. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A15 EP A15 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19600083 ER PT J AU WADE, CE EVANS, J KEIL, LC AF WADE, CE EVANS, J KEIL, LC TI SUPPRESSION OF PITUITARY AVP AND OT CONTENT IN RAT EXPOSED TO SPACE-FLIGHT SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A261 EP A261 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19601508 ER PT J AU WATENPAUGH, DE FORTNEY, SM BALLARD, RE LEE, SMC BENNETT, BS MURTHY, G KRAMER, GC HARGENS, AR AF WATENPAUGH, DE FORTNEY, SM BALLARD, RE LEE, SMC BENNETT, BS MURTHY, G KRAMER, GC HARGENS, AR TI LOWER-BODY NEGATIVE-PRESSURE EXERCISE DURING BED REST MAINTAINS ORTHOSTATIC TOLERANCE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. UNIV TEXAS MED BRANCH,GALVESTON,TX 77555. NR 0 TC 8 Z9 8 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR PY 1994 VL 8 IS 4 BP A261 EP A261 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA ND196 UT WOS:A1994ND19601509 ER PT J AU SCHULZE, NR AF SCHULZE, NR TI FIGURES OF MERIT AND ATTRIBUTES FOR SPACE FUSION PROPULSION SO FUSION TECHNOLOGY LA English DT Article DE SPACE; PROPULSION SYSTEMS; ADVANCED FUELS AB Space-unique fusion engine and flight system design parameters and operational principles permitting the use of fusion energy for space power and propulsion are presented. Solutions that meet those design parameters and operational principles are appropriately addressed during investigations and research on confinement designs for D-He-3 reactions. Once acceptable solutions have been found, space will then be an alternate customer for fusion energy. Key mission parameters are defined for consideration as advancements occur in design and testing of new confinement concepts. Power levels, thrust, firing duration, and mission quality aspects are presented. The importance of research on maintaining stability during burning while removing plasma for propulsion is considered a significant issue in making magnetic fusion reactors practical for space propulsion. Burning efficiency is important for long-duration missions. Space operation of a fusion reactor offers relief from the vacuum constraint that ground systems are required to meet, but space vehicles are mass sensitive, requiring the use of a fuel such as D-He-3 that produces charged particles as ash and requiring the use of compact reactors. RP SCHULZE, NR (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 9 TC 3 Z9 3 U1 0 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD MAR PY 1994 VL 25 IS 2 BP 182 EP 197 PG 16 WC Nuclear Science & Technology SC Nuclear Science & Technology GA MX714 UT WOS:A1994MX71400006 ER PT J AU ARGUS, DF LYZENGA, GA AF ARGUS, DF LYZENGA, GA TI SITE VELOCITIES BEFORE AND AFTER THE LOMA-PRIETA AND GULF OF ALASKA EARTHQUAKES DETERMINED FROM VLBI SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRAIN ACCUMULATION; CALIFORNIA; SLIP AB We use geodetic data from VLBI to determine the pre- and postseismic velocities of two sites. We then place limits on variations in interseismic strain buildup. The 1987 and 1988 Gulf of Alaska earthquakes (each Ms=7.6) broke the Pacific plate interior. During the earthquakes the Cape Yakataga site moved 78 mm toward southwest. During the 1989 Loma Prieta earthquake (Ms=7.1) the Fort Ord site moved 48 mm toward north. Baselines (a) from Fairbanks to Cape Yakataga and (b) from Mojave to Fort Ord change at nearly the same rate before and after the earthquakes. Postseismic transients, which we determine from differences between post- and preseismic rates, are minor: at Cape Yakataga the transient is 3 +/- 4 mm in a postseismic interval of 23 months, and at Fort Ord the transient is 6 +/- 5 mm in 21 months. The slip beneath the Loma Prieta rupture needed to generate the Fort Ord transient is 0.22 +/- 0.19 m, one-tenth the coseismic slip (2 m). We analyze elastic lithosphere-viscous asthenosphere models to determine that the characteristic time describing exponential decay in deep fault slip is longer than 6 years. The VLBI measurements are consistent with uniform interseismic strain buildup. They disagree with fast postseismic rates caused by an asthenosphere with very low viscosity. C1 HARVEY MUDD COLL,DEPT PHYS,CLAREMONT,CA 91711. RP ARGUS, DF (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. RI Argus, Donald/F-7704-2011 NR 12 TC 8 Z9 8 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 MAR 1 PY 1994 VL 21 IS 5 BP 333 EP 336 DI 10.1029/94GL00027 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NA142 UT WOS:A1994NA14200004 ER PT J AU MUSTARD, JF BELL, JF AF MUSTARD, JF BELL, JF TI NEW COMPOSITE REFLECTANCE SPECTRA OF MARS FROM 0.4 TO 3.14 MU-M SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ISM EXPERIMENT AB To verify the quality and accuracy of Phobos-2 ISM spectra of Mars, we have performed comparisons with telescopic data obtained contemporaneously and which have spatial and spectral overlap with the ISM measurements. We find general agreement between the independently-calibrated data sets in terms of spectral shape and absorption band strength and position in the 0.77 to 0.93 mum overlap region. The telescopic data were scaled to the ISM reflectance values in this overlap region to yield new bright and dark region composite reflectance spectra from 0.40 to 3.14 mum. We ascribe the increase in band depth and overall spectral heterogeneity of the ISM data relative to previous telescopic observations to the more than order of magnitude increase in spatial resolution achieved by ISM from Martian orbit. Further increases in spatial resolution from future orbital imaging spectroscopic instruments can be expected to reveal even greater degrees of compositional and mineralogic diversity on Mars. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RP MUSTARD, JF (reprint author), BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912, USA. NR 11 TC 58 Z9 58 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 MAR 1 PY 1994 VL 21 IS 5 BP 353 EP 356 DI 10.1029/94GL00198 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NA142 UT WOS:A1994NA14200009 ER PT J AU SOVERS, OJ AF SOVERS, OJ TI VERTICAL OCEAN LOADING AMPLITUDES FROM VLBI MEASUREMENTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTH AB Vertical ocean loading amplitudes are determined by analysis of IRIS geodetic VLBI data. The 4 nearly diurnal (K1, P1, O1, Q1) and 4 nearly semidiurnal (K2, S2, M2, and N2) component amplitudes can be inferred from the data with accuracies of 1-2 mm. Uncertainties of total displacements can approach 1 cm. Empirically determined total displacements are considerably larger than the values calculated from two geophysical models. The Scherneck model is found to give a better representation of VLBI delay data than the model of Pagiatakis by about 3 mm in residuals at 6 sites. Empirical estimation of the ocean loading amplitudes reduces chi2 by 3067 for the 96 additional degrees of freedom in a fit to 273,000 IRIS VLBI observations, and reduces the RMS residuals by 3 mm relative to a fit using the fixed Scherneck model. Vertical ocean loading amplitudes can thus be inferred from VLBI data at a level which improves the overall model, but detailed assessment of individual tidal components is presently obscured by incomplete modeling at the tidal frequencies. RP SOVERS, OJ (reprint author), JET PROP LAB,MS 238-700,PASADENA,CA 91109, USA. NR 14 TC 13 Z9 13 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 MAR 1 PY 1994 VL 21 IS 5 BP 357 EP 360 DI 10.1029/93GL02648 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NA142 UT WOS:A1994NA14200010 ER PT J AU YOUNG, RE HOUBEN, H TOON, OB AF YOUNG, RE HOUBEN, H TOON, OB TI RADIATIVELY FORCED DISPERSION OF THE MT-PINATUBO VOLCANIC CLOUD AND INDUCED TEMPERATURE PERTURBATIONS IN THE STRATOSPHERE DURING THE 1ST FEW MONTHS FOLLOWING THE ERUPTION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIDAR OBSERVATIONS; AEROSOLS; PLUME; CIRCULATION; MODEL; WAVES; OZONE; JUNE AB A combined 3-dimensional circulation model and aerosol microphysical/transport model is used to simulate the dispersion of the Mt. Pinatubo volcanic cloud in the stratosphere for the first few months following the eruption. Radiative heating of the cloud due to upwelling infrared radiation from the troposphere is shown to be an important factor affecting the transport. Without cloud heating, cloud material stays mostly north of the equator, whereas with cloud heating, the cloud is transported southward across the equator within the first two weeks following the eruption. Generally the simulations agree with TOMS, AVHRR, and SAGE satellite observations showing the latitude distribution of cloud material to be between about 20-degrees-S and 30-degrees-N within the first few months. Temperature perturbations in the stratosphere induced by the aerosol heating are generally 1-4 K, in the range of those observed. C1 SPACE PHYS RES INST,SUNNYVALE,CA 94086. RP YOUNG, RE (reprint author), NASA,AMES RES CTR,M-S 245-3,MOFFETT FIELD,CA 94035, USA. NR 22 TC 40 Z9 40 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 1 PY 1994 VL 21 IS 5 BP 369 EP 372 DI 10.1029/93GL03302 PG 4 WC Geosciences, Multidisciplinary SC Geology GA NA142 UT WOS:A1994NA14200013 ER PT J AU FISCHER, G FROHBERG, K PARRY, ML ROSENZWEIG, C AF FISCHER, G FROHBERG, K PARRY, ML ROSENZWEIG, C TI CLIMATE-CHANGE AND WORLD FOOD-SUPPLY, DEMAND AND TRADE - WHO BENEFITS, WHO LOSES SO GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS LA English DT Article AB This paper summarizes the findings of a major interdisciplinary research effort by scientists in 25 countries. The study examined the potential biophysical responses of major food crops to changing atmospheric composition and climate, and projected potential socioeconomic consequences. In a first step crop models were used to estimate how changing climatic conditions might alter yields of major crops at a number of sites representing both major production areas and vulnerable regions at low, mid and high latitudes. Then a dynamic recursive national-level model of the world food system was used to assess socio-economic impacts for the period 1990 up to year 2060. C1 UNIV BONN,INST AGRARPOLIT,W-5300 BONN,GERMANY. UNIV OXFORD,ENVIRONM CHANGE UNIT,OXFORD,ENGLAND. COLUMBIA UNIV,NEW YORK,NY 10027. GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP FISCHER, G (reprint author), INT INST APPL SYST ANAL,FOOD & AGR PROJECT,A-2361 LAXENBURG,AUSTRIA. NR 28 TC 38 Z9 38 U1 0 U2 8 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0959-3780 J9 GLOBAL ENVIRON CHANG JI Glob. Environ. Change - Human Policy Dimens. PD MAR PY 1994 VL 4 IS 1 BP 7 EP 23 DI 10.1016/0959-3780(94)90018-3 PG 17 WC Environmental Sciences; Environmental Studies; Geography SC Environmental Sciences & Ecology; Geography GA NK750 UT WOS:A1994NK75000002 ER PT J AU NEMIRE, K JACOBY, RH ELLIS, SR AF NEMIRE, K JACOBY, RH ELLIS, SR TI SIMULATION FIDELITY OF A VIRTUAL ENVIRONMENT DISPLAY SO HUMAN FACTORS LA English DT Article ID PERCEIVED EYE LEVEL; SPATIAL INFORMATION; VISUAL-FIELD; PERSPECTIVE; PITCH AB We assessed the degree to which a virtual environment system produced a faithful simulation of three-dimensional space by investigating the influence of a pitched optic array on the perception of gravity-referenced eye level (GREL). We compared the results with those obtained in a physical environment. In a within-subjects factorial design, 12 subjects indicated GREL while viewing virtual three-dimensional arrays at different static orientations. A physical array biased GREL more than did a geometrically identical virtual pitched array. However, addition of two sets of orthogonal parallel lines (a grid) to the virtual pitched array resulted in as large a bias as that obtained with the physical pitched array. The increased bias was caused by the longitudinal, but not the transverse, components of the grid. We discuss implications of our results for spatial orientation models and for designs of virtual displays. RP NASA, AMES RES CTR, SAN JOSE STATE UNIV FDN, MAIL STOP 262-2, MOFFETT FIELD, CA 94035 USA. NR 59 TC 13 Z9 13 U1 0 U2 1 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0018-7208 EI 1547-8181 J9 HUM FACTORS JI Hum. Factors PD MAR PY 1994 VL 36 IS 1 BP 79 EP 93 PG 15 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA NN522 UT WOS:A1994NN52200005 ER PT J AU NANCE, JM GARFIELD, NH PAREDES, JA AF NANCE, JM GARFIELD, NH PAREDES, JA TI STUDYING THE SOCIAL IMPACT OF THE TEXAS SHRIMP CLOSURE SO HUMAN ORGANIZATION LA English DT Note DE COMMITTEE WORK; FISHERIES MANAGEMENT; GOVERNMENT REGULATIONS AB James M. Nance is a fishery biologist with the National Marine Fisheries Service in Galveston, Texas. Nina H. Garfield is Project Manager, Sanctuaries and Reserves Division, National Oceanic and Atmospheric Administration in Washington, DC. J. Anthony Paredes is in the Department of Anthropology at Florida State University in Tallahassee. C1 NOAA,DIV SANCTUARIES & RESERVES,WASHINGTON,DC 20230. FLORIDA STATE UNIV,DEPT ANTHROPOL,TALLAHASSEE,FL 32306. RP NANCE, JM (reprint author), NOAA,NATL MARINE FISHERIES SERV,GALVESTON,TX 77550, USA. NR 9 TC 2 Z9 2 U1 2 U2 3 PU SOC APPLIED ANTHROPOLOGY PI OKLAHOMA CITY PA BUSINESS OFFICE BOX 24083, OKLAHOMA CITY, OK 73124 SN 0018-7259 J9 HUM ORGAN JI Hum. Organ. PD SPR PY 1994 VL 53 IS 1 BP 88 EP 92 PG 5 WC Anthropology; Social Sciences, Interdisciplinary SC Anthropology; Social Sciences - Other Topics GA MX045 UT WOS:A1994MX04500010 ER PT J AU ZAHNLE, K MACLOW, MM AF ZAHNLE, K MACLOW, MM TI THE COLLISION OF JUPITER AND COMET SHOEMAKER-LEVY-9 SO ICARUS LA English DT Article ID ATMOSPHERE; SOLAR AB A simple description of the disruption and deceleration of 100-m- to 5-km-diameter comets striking Jupiter is combined with numerical simulations of the subsequent explosions to predict the fate of Comet Shoemaker-Levy 9. Kilometer-size objects of density 1 g/cm3 explode at about the 10-bar level; a fragment of the same diameter but of density 0.3 g/cm3 explodes at about the 2-bar level. Detailed numerical simulations of the first 3 min of the explosion were performed using the astrophysical hydrodynamics program ZEUS-3D. Our numerical simulations begin either with hot cylinders with dimensions suggested by the disruption and deceleration model or with an initial wake constructed from a moving line charge. In all cases, extensive plumes of hot gas are expelled from the atmosphere. The models with wakes evolve about twice as fast as the initially confined models. Models of both types generate similar pressure waves into the planet. Temperatures and negative hydrogen ion opacities were computed by solving a battery of Saha equations. For atmospheric entry, light curves were computed assuming thermal radiation by clean jovian air with a surface area consistent with the (changing) cross-sectional area of the impactor. On entry the largest bolides could be very bright, possibly as bright as Jupiter for observers placed to see them, although for kilometer-size impactors the luminosity peak is obscured by clouds. The timescale is about 10 sec. For the fireball, light curves were computed from the numerical simulations assuming a grey atmosphere. Metals from the vaporized comet provide electrons that dramatically increase the opacity of Jovian air at low temperature; the resulting effective radiating temperature of the fireball is of order 3000 K. The fireball rises through and above the atmosphere, brightening at first as its surface area increases, but later fading to invisibility as its temperature drops and its opacity plummets. The timescale is about 100 sec. (C) 1994 Academic Press, Inc. C1 UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP ZAHNLE, K (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-3,MOFFETT FIELD,CA 94035, USA. NR 35 TC 101 Z9 101 U1 1 U2 5 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 MAR PY 1994 VL 108 IS 1 BP 1 EP 17 DI 10.1006/icar.1994.1038 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NP778 UT WOS:A1994NP77800001 PM 11539477 ER PT J AU LELLOUCH, E ROMANI, PN ROSENQVIST, J AF LELLOUCH, E ROMANI, PN ROSENQVIST, J TI THE VERTICAL-DISTRIBUTION AND ORIGIN OF HCN IN NEPTUNE ATMOSPHERE SO ICARUS LA English DT Article ID METASTABLE NITROGEN-ATOMS; TITANS UPPER-ATMOSPHERE; ION-MOLECULE REACTIONS; MILLIMETER OBSERVATIONS; TEMPERATURE-DEPENDENCE; PLANETARY-ATMOSPHERES; VOYAGER MEASUREMENTS; RADICAL REACTIONS; COMETARY COMAE; RATE CONSTANTS AB Measurements and modeling of the (3-2) rotational line of hydrogen cyanide at 265.9 GHz in Neptune's atmosphere are presented. High signal-to-noise observations, performed at IRAM in October 1991 and April 1992, provide information on the HCN vertical distribution in Neptune's stratosphere. The HCN mixing ratio is found to be nearly uniform with height above the condensation level (3 mbar). Best fits occur for HCN distributions that have a slight increase with altitude (HCN scale height approximately 5x the atmospheric scale height). A least-squares analysis yields a mixing ratio of (3.2 +/- 0.8) 10(-10) at 2 mbar and a mean mixing ratio scale height of 250(+750/-110) km in the 0.1-3 mbar region. To interpret these results, we developed a photochemical model of HCN, based in part upon the hydrocarbon model of Romani et al. (Icarus, 106, 442-463 (1993)). HCN formation is initiated by the reaction between CH3 radicals, produced from methane photochemistry, and N atoms. The primary sink for HCN is condensation, with minor contributions from photolysis and chemical losses. Two possible sources of N atoms are investigated: (1) infall of N escaped from Triton's upper atmosphere, and (2) galactic cosmic ray (GCR) impact on internal N2. For the Triton source, a total N flux of 5 x 10(24) atoms sec-1 is necessary to match the HCN abundance, and the observed HCN profile suggests an eddy diffusion profile with a rapid transition from slow mixing at p greater-than-or-equal-to 2 mbar to rapid mixing at lower pressures. The required N flux is approximately 50% of the estimated N escape from Triton's upper atmosphere. For the GCR source, a simple model of ionization and dissociation of N2 by cosmic rays was developed. In this case, both smooth and discontinuous eddy K profiles satisfy the observations. The tropospheric N2 mixing ratio required to fit the HCN observations is in the range 0.3-1.7% if our GCR interaction model is correct. The range results from uncertainties in the chemistry of the NH radical and in the eddy K profile. Our GCR model, however, disagrees with earlier models by Capone et al. (Icarus 55, 73-82 (1983)) and, if the latter are correct, the required N2 mixing ratios are a factor of 6 larger. The GCR source leads to a higher formation rate of HCN ice than the Triton source, but one not large enough for HCN ice to be detected in the Voyager IRIS spectra. Additionally, the GCR source implies the possible formation of methylenimine (CH2NH) in amounts comparable to HCN. Given the uncertainties on (i) the transport and possible ionization of N in Neptune's magnetosphere, and the fate of N+ reaching Neptune's upper atmosphere and (ii) the N2 mixing ratio in Neptune' s deep atmosphere, we suggest that both sources of N atoms may significantly contribute to the formation of HCN. (C) 1994 Academic Press, Inc. C1 NASA,GODDARD SPACE FLIGHT CTR,GSFC,GREENBELT,MD 20771. RP LELLOUCH, E (reprint author), OBSERV PARIS,DESPA,F-92195 MEUDON,FRANCE. RI Romani, Paul/D-2729-2012 NR 93 TC 45 Z9 45 U1 1 U2 5 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 MAR PY 1994 VL 108 IS 1 BP 112 EP 136 DI 10.1006/icar.1994.1045 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NP778 UT WOS:A1994NP77800008 ER PT J AU ZENT, AP MCKAY, CP AF ZENT, AP MCKAY, CP TI THE CHEMICAL-REACTIVITY OF THE MARTIAN SOIL AND IMPLICATIONS FOR FUTURE MISSIONS SO ICARUS LA English DT Article ID VIKING BIOLOGY EXPERIMENTS; LIFE DETECTION EXPERIMENT; MARS; MODEL; CHEMISTRY; PEROXIDE; SEARCH; CLAYS AB Possible interpretations of the results of the Viking Biology Experiments suggest that > 1 ppm of a thermally labile oxidant, perhaps H2O2, and about 10 ppm of a thermally stable oxidant are present in the martian soil. We reexamine these results and discuss implications for future missions, the search for organics on Mars, and the possible health and engineering effects for human exploration. We conclude that further characterization of the reactivity of the martian regolith materials is warranted-although if our present understanding is correct the oxidant does not pose a hazard to humans. There are difficulties in explaining the reactivity of the Martian soil by oxidants. Most bulk phase compounds that are capable of oxidizing H2O to O2 per the Gas Exchange Experiment (GEx) are thermally labile or unstable against reduction by atmospheric CO2. Models invoking trapped O2 or peroxynitrates (NOO2-) require an unlikely geologic history for the Viking Lander 2 site. Most suggested oxidants, including H2O2, are expected to decompose rapidly under martian UV. Nonetheless, we conclude that the best model for the martian soil contains oxidants produced by heterogeneous chemical reactions with a photochemically produced atmospheric oxidant. The GEx results may be due to catalytic decomposition of an unstable oxidizing material by H2O. We show that interfacial reaction sites covering <1% of the available soil surfaces could explain the Viking Biology Experiments results. Due to the low concentration of reactive agents, the fact that they are probably composed of elements that are common in the soil, and their observed instability, it is unlikely that a sample return mission would be effective in identifying them. Methods for in situ characterization of the oxidant must be developed that are consistent with the dry state of the soil. Traditional terrestrial methods of characterizing the soil Eh are unsuitable. Alternative methods must be developed; one approach under development involves exposing a wide variety of materials to the martian regolith and monitoring their reactions. (C) 1994 Academic Press, Inc. C1 NASA,AMES RES CTR,CTR MARS EXPLORAT,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RP ZENT, AP (reprint author), NASA,AMES RES CTR,INST SETI,MOFFETT FIELD,CA 94035, USA. NR 55 TC 133 Z9 134 U1 2 U2 9 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 MAR PY 1994 VL 108 IS 1 BP 146 EP 157 DI 10.1006/icar.1994.1047 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NP778 UT WOS:A1994NP77800010 ER PT J AU MENZIES, RT KILLINGER, DK AF MENZIES, RT KILLINGER, DK TI IR LASERS TUNE IN TO THE ENVIRONMENT SO IEEE CIRCUITS AND DEVICES MAGAZINE LA English DT Article ID REMOTE MEASUREMENT C1 UNIV S FLORIDA,DEPT PHYS,TAMPA,FL 33620. RP MENZIES, RT (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 7 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 8755-3996 J9 IEEE CIRCUIT DEVIC JI IEEE Circuit Devices Mag. PD MAR PY 1994 VL 10 IS 2 BP 24 EP 29 DI 10.1109/101.268862 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA NB119 UT WOS:A1994NB11900008 ER PT J AU ENCARNACAO, J FOLEY, J BRYSON, S FEINER, SK GERSHON, N AF ENCARNACAO, J FOLEY, J BRYSON, S FEINER, SK GERSHON, N TI RESEARCH ISSUES IN PERCEPTION AND USER INTERFACES SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Article; Proceedings Paper CT 1993 ACM/IEEE 2nd Symposium on Solid Modeling and Applications CY MAY 19-21, 1993 CL MONTREAL, CANADA SP ASSOC COMP MACHINERY, IEEE C1 MITRE CORP,BEDFORD,MA 01730. GEORGIA INST TECHNOL,ATLANTA,GA 30332. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. COLUMBIA UNIV,NEW YORK,NY 10027. RP ENCARNACAO, J (reprint author), FRAUNHOFER INST COMP GRAPH,DARMSTADT,GERMANY. NR 0 TC 8 Z9 8 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0272-1716 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD MAR PY 1994 VL 14 IS 2 BP 67 EP 69 DI 10.1109/38.267474 PG 3 WC Computer Science, Software Engineering SC Computer Science GA MY702 UT WOS:A1994MY70200011 ER PT J AU ROBERTSON, PK EARNSHAW, RA THALMANN, D GRAVE, M GALLOP, J DEJONG, EM AF ROBERTSON, PK EARNSHAW, RA THALMANN, D GRAVE, M GALLOP, J DEJONG, EM TI RESEARCH ISSUES IN THE FOUNDATIONS OF VISUALIZATION SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Article; Proceedings Paper CT 1993 ACM/IEEE 2nd Symposium on Solid Modeling and Applications CY MAY 19-21, 1993 CL MONTREAL, CANADA SP ASSOC COMP MACHINERY, IEEE C1 UNIV LEEDS, LEEDS LS2 9JT, W YORKSHIRE, ENGLAND. SWISS FED INST TECHNOL, Lausanne, SWITZERLAND. RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. JET PROP LAB, PASADENA, CA 91109 USA. ONERA DMI, TOULOUSE, FRANCE. RP ROBERTSON, PK (reprint author), CSIRO, CANBERRA, ACT 2601, AUSTRALIA. RI Thalmann, Daniel/A-4347-2008 OI Thalmann, Daniel/0000-0002-0451-7491 NR 10 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0272-1716 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD MAR PY 1994 VL 14 IS 2 BP 73 EP 76 DI 10.1109/38.267476 PG 4 WC Computer Science, Software Engineering SC Computer Science GA MY702 UT WOS:A1994MY70200013 ER PT J AU LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM AF LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM TI PHOTORESPONSE MODEL FOR SI1-XGEX/SI HETEROJUNCTION INTERNAL PHOTOEMISSION INFRARED DETECTOR SO IEEE ELECTRON DEVICE LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY AB A photoresponse model has been developed for the Si1-xGex/Si heterojunction internal photoemission (HIP) infrared detector at wavelengths corresponding to photon energies less than the Fermi energy. A Si0.7Ge0.3/Si HIP detector with a cutoff wavelength of 23 mu m and an emission coefficient of 0.4 eV(-1) has been demonstrated. The model agrees with the measured detector response at lambda > 8 mu m The potential barrier determined by the model is in close agreement (difference similar to 4 meV) with the potential barrier determined by the Richardson plot, compared to the discrepancies of 20-50 meV usually observed for PtSi Schottky detectors. RP LIN, TL (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 9 TC 13 Z9 21 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 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD MAR PY 1994 VL 15 IS 3 BP 103 EP 105 DI 10.1109/55.285388 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA NF129 UT WOS:A1994NF12900008 ER PT J AU DUFFY, DG AF DUFFY, DG TI RESPONSE OF A GROUNDED DIELECTRIC SLAB TO AN IMPULSE LINE SOURCE USING LEAKY MODES SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID AXISYMMETRIC BOREHOLES AB This paper describes how expansions in leaky (or improper) modes may be used to represent the continuous spectrum in an open radiating waveguide. The technique requires a thorough knowledge of the life history of the improper modes as they migrate from improper to proper Riemann surfaces. The method is illustrated by finding the electric field resulting from an impulsively forced current located in the free space above a grounded dielectric slab. RP DUFFY, DG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 14 TC 4 Z9 4 U1 2 U2 2 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 MAR PY 1994 VL 42 IS 3 BP 340 EP 346 DI 10.1109/8.280720 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA NJ921 UT WOS:A1994NJ92100007 ER PT J AU MENDIS, S KEMENY, SE FOSSUM, ER AF MENDIS, S KEMENY, SE FOSSUM, ER TI CMOS ACTIVE PIXEL IMAGE SENSOR SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Note AB A new CMOS active pixel image sensor is reported. The sensor uses a 2.0 mu m double-poly, double-metal foundry CMOS process and is realized as a 128 x 128 array of 40 mu m x 40 mu m pixels. The sensor features TTL compatible voltages, low noise and large dynamic range, and will be useful in machine vision and smart sensor applications. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP MENDIS, S (reprint author), COLUMBIA UNIV,DEPT ELECT ENGN,NEW YORK,NY 10027, USA. OI Fossum, Eric/0000-0002-6232-0515 NR 9 TC 84 Z9 84 U1 1 U2 11 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 MAR PY 1994 VL 41 IS 3 BP 452 EP 453 DI 10.1109/16.275235 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA NF112 UT WOS:A1994NF11200025 ER PT J AU WANG, JR MENEGHINI, R KUMAGAI, H WILHEIT, TT BONCYK, WC RACETTE, P TESMER, JR MAVES, B AF WANG, JR MENEGHINI, R KUMAGAI, H WILHEIT, TT BONCYK, WC RACETTE, P TESMER, JR MAVES, B TI AIRBORNE ACTIVE AND PASSIVE MICROWAVE OBSERVATIONS OF SUPER TYPHOON FLO SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID 183 GHZ; RADIOMETRIC MEASUREMENTS; PRECIPITATION PROFILES; RAINFALL; AIRCRAFT; SATELLITE; RADAR; HURRICANES; RETRIEVAL; OCEANS AB Airborne microwave measurements of precipitation associated with Super Typhoon Flo in the western North Pacific were conducted during September 16-18, 1990. The sensor package aboard the NASA DC-8 aircraft included a dual-frequency precipitation radar at 10 GHz and 34 GHz and a host of radiometers operating at 10 GHz, 18 GHz, 19 GHz, 34 GHz, and 92 GHz, as well as three frequencies near the strong water vapor absorption line of 183.3 GHz. The measurements were made during a few passes over the storm center, and active and passive microwave signatures of the rainbands were detected with a fine spatial resolution. The relationship between the measured brightness temperature and radar-estimated rain rate is examined at the frequencies between 10-92 GHz. At both 34 and 92 GHz this relationship is analyzed with the 10 GHz radar reflectivity factor measured at altitudes above the freezing layer as a further constraint. The results show that frozen hydrometeors strongly scatter radiation at these frequencies, especially at 92 GHz. It was shown from a close examination of both active and passive microwave signatures that a significant scattering of radiation at frequencies greater-than-or-equal-to 18 GHz occurred in the inner eyewall at altitudes of 3-8 km. This scattering of microwave radiation by hydrometeors in both liquid and frozen forms was discussed under our current understanding of the scattering mechanism. C1 COMMUN RES LABS,KOGANEI,TOKYO 184,JAPAN. TEXAS A&M UNIV,DEPT METEOROL,COLLEGE STN,TX 77843. RP WANG, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. RI Wilheit, Thomas/G-9438-2012 NR 30 TC 17 Z9 17 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1994 VL 32 IS 2 BP 231 EP 242 DI 10.1109/36.295037 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 NU663 UT WOS:A1994NU66300001 ER PT J AU HARDING, DJ BUFTON, JL FRAWLEY, JJ AF HARDING, DJ BUFTON, JL FRAWLEY, JJ TI SATELLITE LASER ALTIMETRY OF TERRESTRIAL TOPOGRAPHY - VERTICAL ACCURACY AS A FUNCTION OF SURFACE SLOPE, ROUGHNESS, AND CLOUD COVER SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB Satellite laser altimetry provides a method to obtain global digital topographic data of high accuracy by measuring the round-trip time-of-flight of laser pulses reflected from the Earth's surface. Analysis of the sensitivity of laser ranging errors to surface conditions indicates that predicted single-shot range errors are primarily dependent on surface slope. Range errors are less sensitive to variations in surface roughness or reflectivity. Values of total surface slope and roughness for nine terrestrial landforms, derived from digital elevation data at a 186-m-length scale, vary from 2-degrees to 40-degrees and 0.8 to 15 m, respectively, at a 90% frequency of occurrence. This range of surface morphologies yields a variation in single-shot laser ranging error from 0.4 to 8 m, assuming system parameters for the proposed Topographic Mapping Laser Altimeter (TMLA) and a nominal 30% surface reflectivity. The total elevation accuracy of data obtained via satellite laser altimetry, although dominated by the range error, is also a function of additional error sources, including orbit ephemeris, atmospheric, and calibration errors. Averaging of multiple laser measurements improves the vertical accuracy of the elevation data by statistical reduction of random errors. During a three-year mission, two to three laser measurements will be acquired, on average, for each 200-m footprint at low to moderate latitudes, accounting for the latidudinal variation of ground track spacing and cloud cover. For high-latitude regions, the narrow spacing of satellite ground tracks in a polar orbit will provide frequent repeat observations yielding, on average, 4 to 25 measurements of each footprint over the Antarctic and Greenland ice sheets. Averaging of these multiple repeat observations at high latitude will yield an improvement in vertical accuracy by a factor of two to five. C1 HERRING BAY GEOPHYS, DUNKIRK, MD 20754 USA. RP HARDING, DJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Namikawa, Laercio/C-5559-2013; Harding, David/F-5913-2012 OI Namikawa, Laercio/0000-0001-7847-1804; NR 23 TC 25 Z9 36 U1 0 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1994 VL 32 IS 2 BP 329 EP 339 DI 10.1109/36.295048 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300012 ER PT J AU WAY, J RIGNOT, EJM MCDONALD, KC OREN, R KWOK, R BONAN, G DOBSON, MC VIERECK, LA ROTH, JE AF WAY, J RIGNOT, EJM MCDONALD, KC OREN, R KWOK, R BONAN, G DOBSON, MC VIERECK, LA ROTH, JE TI EVALUATING THE TYPE AND STATE OF ALASKA TAIGA FORESTS WITH IMAGING RADAR FOR USE IN ECOSYSTEM MODELS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ATMOSPHERE-BIOSPHERE EXCHANGE; AMERICAN BOREAL FORESTS; INTERIOR ALASKA; CARBON-DIOXIDE; WALNUT ORCHARD; PRODUCTIVITY; BACKSCATTER; BUDGET; TREES; SAR AB Changes in the seasonal CO2 flux of the boreal forests may result from increased atmospheric CO2 concentrations and associated global warming patterns. To monitor this potential change, a combination of information derived from remote sensing data, including forest type and growing season length, and ecophysiological models which predict the CO2 fluX and its seasonal amplitude based on meteorological data, are required. In this paper we address the use of synthetic aperture radar (SAR) to map forest type and monitor canopy and soil freeze/thaw, which define the growing season for conifers, and leaf on/off, which defines the growing season for deciduous species. Aircraft SAR (AIRSAR) data collected in March 1988 during a freeze/thaw event are used to generate species maps and to determine the sensitivity of SAR to canopy freeze/thaw transitions. These data are also used to validate a microwave scattering model which is then used to determine the sensitivity of SAR to leaf on/off transitions and soil freeze/thaw. Finally, a CO2, flux algorithm is presented which utilizes SAR data and an ecophysiological model to estimate CO2 flux. CO2 flux MaPS are generated, from which areal estimates Of CO2 flux are derived. C1 NATL CTR ATMOSPHER RES,BOULDER,CO 80307. UNIV MICHIGAN,ANN ARBOR,MI 48109. RP WAY, J (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Rignot, Eric/A-4560-2014 OI Kwok, Ron/0000-0003-4051-5896; Rignot, Eric/0000-0002-3366-0481 NR 48 TC 50 Z9 51 U1 0 U2 6 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 MAR PY 1994 VL 32 IS 2 BP 353 EP 370 DI 10.1109/36.295050 PG 18 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300014 ER PT J AU KWOK, R RIGNOT, EJM WAY, J FREEMAN, A HOLT, J AF KWOK, R RIGNOT, EJM WAY, J FREEMAN, A HOLT, J TI POLARIZATION SIGNATURES OF FROZEN AND THAWED FORESTS OF VARYING ENVIRONMENTAL STATE SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB During the two different overflights of the Bonanza Creek Experimental Forest (near Fairbanks, Alaska) by the NASA/JPL radar polarimeter in March 1988, the environmental conditions over the region changed significantly with temperatures ranging from unseasonably warm (1 to 9-degrees-C) during one day to well below freezing (-8 to -15-degrees-C) during the other. The moisture content of the snow and trees changed from a liquid to frozen state causing significant changes in the radiometric and polarimetric responses of the forest to the radar wave. The L-band polarimetric observations are summarized in this paper. Up to a 6 dB change in the backscatter was observed in certain forest stands at L-band. Features extracted from the Stokes matrices of the same stands from the thawed and frozen days suggest the changes in the relative contribution of the different scattering mechanisms to the radar return. Comparison of the polarimetric signatures indicate relatively higher contribution from diffuse scatterers on the thawed day than on the frozen day. The sensitivity of the polarimetric signatures to changing environmental conditions is clearly demonstrated. C1 CALTECH,DEPT GEOL,PASADENA,CA 91125. RP KWOK, R (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Holt, John/C-4896-2009; Rignot, Eric/A-4560-2014 OI Kwok, Ron/0000-0003-4051-5896; Rignot, Eric/0000-0002-3366-0481 NR 11 TC 23 Z9 25 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 MAR PY 1994 VL 32 IS 2 BP 371 EP 381 DI 10.1109/36.295051 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300015 ER PT J AU RANSON, KJ SUN, GQ AF RANSON, KJ SUN, GQ TI MAPPING BIOMASS OF A NORTHERN FOREST USING MULTIFREQUENCY SAR DATA SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID RADAR BACKSCATTER; MODEL AB The results of mapping standing biomass for a northern forest in Maine, using NASA/JPL AIRSAR polarimetric radar data, is presented. By examining the dependence of backscattering on standing biomass using backscatter modeling and aircraft data, it was determined, in agreement with other recent reports, that the cross-polarized (HV) data from longer wavelengths (L, P-band) were the best radar channels for mapping total above-ground forest biomass. The radar signal appeared to lose sensitivity to changes in biomass for dry biomass levels beyond about 15 k g/M2 (150 Mton/Ha). The ratio of HV backscattering from two bands, a longer wavelength P (wavelength = 68 cm) or L band (24 cm) to a shorter wavelength C band (6 cm), enhanced the correlation of the image signature to standing biomass (r2 = 0.83 for P/C and r2 = 0.79 for L/C) and showed increased sensitivity to dry biomass beyond 15 kg/M2. C1 SCI SYST & APPLICAT INC,LANHAM,MD 20706. RP RANSON, KJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771, USA. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 16 TC 128 Z9 136 U1 3 U2 14 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 MAR PY 1994 VL 32 IS 2 BP 388 EP 396 DI 10.1109/36.295053 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300017 ER PT J AU VANDEGRIEND, AA OWE, M AF VANDEGRIEND, AA OWE, M TI THE INFLUENCE OF POLARIZATION ON CANOPY TRANSMISSION PROPERTIES AT 6.6 GHZ AND IMPLICATIONS FOR LARGE-SCALE SOIL-MOISTURE MONITORING IN SEMIARID ENVIRONMENTS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID MICROWAVE EMISSION; SURFACE MOISTURE; VEGETATION; SCATTERING AB Nimbus/SMMR 6.6 GHz data were used together with an extensive data base of surface moisture to study the influence of polarization on radiative transfer characteristics of savannah vegetation in south-eastern Botswana. Ratios of vertical and horizontal polarization optical depths and ratios of albedos were found to be almost constant throughout a three-year period. This conclusion led to a new approach to eliminate the vegetation components in the remotely sensed brightness temperatures, which is important for soil moisture monitoring from space. Using the same data set, this dual-polarization approach was compared with an earlier described synergistic approach, in which NDVI was used to eliminate the vegetation effects. The root mean square error between ground based soil moisture and satellite estimated surface soil moisture was reduced to 1.2% by volume from 5% by volume using the dual polarization approach. C1 NASA,GODDARD SPACE FLIGHT CTR,GSFC,HYDROL SCI BRANCH,GREENBELT,MD 20771. RP VANDEGRIEND, AA (reprint author), FREE UNIV AMSTERDAM,INST EARTH SCI,1081 HV AMSTERDAM,NETHERLANDS. NR 23 TC 28 Z9 28 U1 0 U2 3 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 MAR PY 1994 VL 32 IS 2 BP 409 EP 415 DI 10.1109/36.295055 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 NU663 UT WOS:A1994NU66300019 ER PT J AU CHAUHAN, NS LEVINE, DM AF CHAUHAN, NS LEVINE, DM TI DISCRETE SCATTER MODEL FOR MICROWAVE RADAR AND RADIOMETER RESPONSE TO CORN - COMPARISON OF THEORY AND DATA SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ELECTROMAGNETIC BACKSCATTERING; DIELECTRIC DISKS; VEGETATION; LAYER; SOIL AB As part of the Multisensor Aircraft Campaign, MACHYDRO, two microwave sensors, NASA's Airborne Synthetic Aperture Radar (AIRSAR) and Pushbroom Microwave Radiometer (PBMR) collected data over the same corn fields during the summer of 1990. During these flights, measurements were made on the ground of soil moisture and plant parameters. In this paper the measured canopy and soil parameters are used in a discrete scatter model to predict the response of both sensors (radar and radiometer). A distorted Born approximation is used to compute the scattering coefficient for the corn canopy. The backscatter coefficient gives the radar response and the radiometer response is obtained by integrating the bistatic coefficient over, all scattering angles above ground. The objective of this analysis is to test the model and, in particular, to determine how well a single set of plant parameters and single model can yield agreement with both the radar and radiometer measurements. The model values are in reasonably good agreement with the measurements at horizontal polarization and reflect observed changes in soil moisture. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771. RP CHAUHAN, NS (reprint author), GEORGE WASHINGTON UNIV,DEPT ELECT ENGN,WASHINGTON,DC 20052, USA. NR 24 TC 52 Z9 58 U1 1 U2 4 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 MAR PY 1994 VL 32 IS 2 BP 416 EP 426 DI 10.1109/36.295056 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300020 ER PT J AU ENTEKHABI, D NAKAMURA, H NJOKU, EG AF ENTEKHABI, D NAKAMURA, H NJOKU, EG TI SOLVING THE INVERSE PROBLEMS FOR SOIL-MOISTURE AND TEMPERATURE PROFILES BY SEQUENTIAL ASSIMILATION OF MULTIFREQUENCY REMOTELY-SENSED OBSERVATIONS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID MICROWAVE EMISSION; MODEL; SURFACES AB An algorithm is developed to solve the inverse problem for the retrieval of the soil moisture and temperature profiles based on remotely sensed observations of multispectral irradiance. A model of coherent wave radiative transfer and a model of coupled heat and moisture diffusion, in porous media are combined in order to estimate the liquid volumetric water content and temperature profiles in a soil column using low-frequency passive microwave and infrared emitted radiation observations and without the use of empirical relations. The central purpose of this mainly theoretical paper is to pose the inverse problem and present the physics-based algorithm as the solution. The algorithm is here tested on a basic synthetic example in order to ascertain that the retrieval is feasible. Additional work in the future is necessary and planned in order to test the algorithm with field observations, extend it to include vegetation, and refine it for detail in the specification of heterogeneity in soil types and boundary conditions. C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91106. RP ENTEKHABI, D (reprint author), MIT,DEPT CIVIL & ENVIRONM ENGN,CAMBRIDGE,MA 02139, USA. NR 31 TC 181 Z9 199 U1 1 U2 14 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 MAR PY 1994 VL 32 IS 2 BP 438 EP 448 DI 10.1109/36.295058 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA NU663 UT WOS:A1994NU66300022 ER PT J AU BARAM, Y AF BARAM, Y TI CORRECTIVE MEMORY BY A SYMMETRICAL SPARSELY ENCODED NETWORK SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE NEURAL NETWORKS; CORRECTIVE MEMORY; ASSOCIATIVE MEMORY; SPARSE ENCODING ID ASSOCIATIVE MEMORY; NEURAL NETWORKS; CAPACITY AB A neural network that retrieves stored binary vectors, when probed by possibly corrupted versions of them, is presented. It employs sparse ternary internal coding and autocorrelation (Hebbian) storage. It is symmetrically structured and, consequently, can be folded into a feedback configuration. Bounds on the network parameters are derived from probabilistic considerations. It is shown that when the input dimension is n, the proportional activation radius is rho and the network size is 2nun With nu > 1 - h2(rho), the equilibrium capacity is at least 2alphan/8nrho(1 - rho) for any alpha < 1 - h2 (rho), where h2 (.) is the binary entropy. A similar capacity bound is derived for the correction of errors of proportional size rho or less, when rho less-than-or-equal-to 0.3. The performance of a finite-size symmetric network is examined by simulation and found to exceed, at the cost of higher connectivity, that of the Kanerva model, operating as a content addressable memory. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BARAM, Y (reprint author), TECHNION ISRAEL INST TECHNOL,DEPT COMP SCI,IL-32000 HAIFA,ISRAEL. NR 21 TC 3 Z9 3 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 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAR PY 1994 VL 40 IS 2 BP 429 EP 438 DI 10.1109/18.312165 PG 10 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA NX931 UT WOS:A1994NX93100012 ER PT J AU ZENG, Z GOODMAN, RM SMYTH, P AF ZENG, Z GOODMAN, RM SMYTH, P TI DISCRETE RECURRENT NEURAL NETWORKS FOR GRAMMATICAL INFERENCE SO IEEE TRANSACTIONS ON NEURAL NETWORKS LA English DT Article AB We describe a novel neural architecture for learning deterministic context-free grammars, or equivalently, deterministic pushdown automata. The unique feature of the proposed network is that it forms stable state representations during learning-previous work has shown that conventional analog recurrent networks can be inherently unstable in that they cannot retain their state memory for long input strings. We have recently introduced the discrete recurrent network architecture for learning finite-state automata. Here we extend this model to include a discrete external stack with discrete symbols. A composite error function is described to handle the different situations encountered in learning. The pseudo-gradient learning method (introduced in previous work) is in turn extended for the minimization of these error functions. Empirical trials validating the effectiveness of the pseudo-gradient learning method are presented, for networks both with and without an external stack. Experimental results show that the new networks are successful in learning some simple pushdown automata, though overfitting and non-convergent learning can also occur. Once learned, the internal representation of the network is provably stable; i.e., it classifies unseen strings of arbitrary length with 100% accuracy. C1 JET PROP LAB,PASADENA,CA 91109. RP ZENG, Z (reprint author), CALTECH,DEPT ELECT ENGN,PASADENA,CA 91125, USA. NR 18 TC 29 Z9 29 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1045-9227 J9 IEEE T NEURAL NETWOR JI IEEE Trans. Neural Netw. PD MAR PY 1994 VL 5 IS 2 BP 320 EP 330 DI 10.1109/72.279194 PG 11 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA NH768 UT WOS:A1994NH76800015 PM 18267800 ER PT J AU LEE, S AF LEE, S TI SUBASSEMBLY IDENTIFICATION AND EVALUATION FOR ASSEMBLY PLANNING SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS LA English DT Letter AB This paper presents a method for the automatic generation of assembly sequences from a liaison graph representation of an assembly through the recursive decomposition of assembly into subassemblies. In order to increase the planning efficiency, the proposed assembly planning system automatically identifies and avoids those decomposition that incur physically infeasible assembly operation. This is achieved by merging those parts that can not be mutually separable at the current stage of assembly planning due to interconnection infeasibility as well as functional dependency. The above merging process transforms the original liaison graph into an abstract liaison graph with smaller number of nodes. Then, weights are assigned to each liaison of abstract liaison graph based on the stability and structural connectivity associated with liaison such that these weights are used to extract the tentative subassemblies. To select preferred subassemblies, the extracted tentative subassemblies are evaluated based on the subassembly selection indices defined in terms of mobility, structural preference, stability, and parallelism. Furthermore, by adjusting the assembly coefficients of subassembly selection indices according to given assembly environment, an optimal assembly sequence can be generated. The application of the proposed planning system to the tabletop vise assembly is illustrated as an example. C1 UNIV SO CALIF,DEPT ELECT ENGN SYST & COMP SCI,LOS ANGELES,CA 90089. RP LEE, S (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 20 TC 38 Z9 49 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9472 J9 IEEE T SYST MAN CYB JI IEEE Trans. Syst. Man Cybern. PD MAR PY 1994 VL 24 IS 3 BP 493 EP 503 DI 10.1109/21.278997 PG 11 WC Computer Science, Cybernetics; Engineering, Electrical & Electronic SC Computer Science; Engineering GA NJ725 UT WOS:A1994NJ72500010 ER PT J AU DAS, L AF DAS, L TI PERFORMANCE-MEASUREMENT TAKES CENTER STAGE AT JOHNSON-SPACE-CENTER SO INDUSTRIAL ENGINEERING LA English DT Article RP DAS, L (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,JOHNSON CONTROLS WORLD SERV INC,HOUSTON,TX 77058, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU INST INDUSTRIAL ENGINEERS PI NORCROSS PA 25 TECHNOLOGY PARK/ATLANTA, NORCROSS, GA 30092 SN 0019-8234 J9 IND ENG PD MAR PY 1994 VL 26 IS 3 BP 24 EP & PG 0 WC Engineering, Industrial SC Engineering GA NB104 UT WOS:A1994NB10400005 ER PT J AU HARVEY, PM ERICKSON, EF AF HARVEY, PM ERICKSON, EF TI SOFIA - STRATOSPHERIC OBSERVATORY FOR INFRARED ASTRONOMY SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Conference on Infrared Physics (CIRPS 5): Topical Conference on Infrared Astrophysics CY JUN 20-25, 1993 CL CTR STEFANO FRANSCINI, MONTE VERITA, ASCONA, SWITZERLAND SP SWISS SOC ASTROPHYS & ASTRON, SWISS PHYS SOC, SWISS ACAD NAT SCI, COMM SPACE RES HO CTR STEFANO FRANSCINI, MONTE VERITA AB We describe the capabilities and status of the SOFIA project, a 2.5-m airborne observatory for observations from visible to sub-millimeter wavelengths. Properties of likely instrumentation and the expected science results are also summarized along with a description of the expected operating plan for the observatory and status of technology drivers. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HARVEY, PM (reprint author), UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 153 EP 160 DI 10.1016/1350-4495(94)90076-0 PG 8 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100009 ER PT J AU HOFFMANN, WF FAZIO, GG SHIVANANDAN, K HORA, JL DEUTSCH, LK AF HOFFMANN, WF FAZIO, GG SHIVANANDAN, K HORA, JL DEUTSCH, LK TI ASTRONOMICAL OBSERVATIONS WITH THE MIDINFRARED ARRAY CAMERA, MIRAC SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article AB MIRAC is a Mid-InfraRed Array Camera built for ground-based astronomy by Steward Observatory at the University of Arizona, Harvard Smithsonian Center for Astrophysics, and the Center for Advanced Space Sensing at the Naval Research Laboratory. It utilizes a Hughes Aircraft Co. 20 x 64 pixel arsenic-doped silicon impurity-band-conduction hybrid array with a capacitance-transimpedance-amplifierreadout (CRC 444A). The detector has an operating wavelength range of 2-26 mum. The camera has been operated on the Steward Observatory 1.5- and 2.3-m and the NASA 3-m IRTF telescopes to observe a variety of sources including solar system objects, young stellar objects, planetary nebulae, infrared-luminous galaxies, star forming regions, and brown dwarfs. C1 GEN RES CORP, DIV SPACE, SANTA BARBARA, CA USA. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA. UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. RP HOFFMANN, WF (reprint author), UNIV ARIZONA, STEWARD OBSERV, TUCSON, AZ 85721 USA. OI Hora, Joseph/0000-0002-5599-4650 NR 17 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 175 EP 194 DI 10.1016/1350-4495(94)90079-5 PG 20 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100012 ER PT J AU KOSTIUK, T AF KOSTIUK, T TI PHYSICS AND CHEMISTRY OF UPPER ATMOSPHERES OF PLANETS FROM INFRARED OBSERVATIONS SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Conference on Infrared Physics (CIRPS 5): Topical Conference on Infrared Astrophysics CY JUN 20-25, 1993 CL CTR STEFANO FRANSCINI, MONTE VERITA, ASCONA, SWITZERLAND SP SWISS SOC ASTROPHYS & ASTRON, SWISS PHYS SOC, SWISS ACAD NAT SCI, COMM SPACE RES HO CTR STEFANO FRANSCINI, MONTE VERITA ID JOVIAN GLOBAL OSCILLATIONS; NATURAL LASER-EMISSION; HETERODYNE SPECTROSCOPY; MARTIAN ATMOSPHERE; STRATOSPHERIC ETHANE; SEASONAL-VARIATION; VENUS MESOSPHERE; WIND VELOCITIES; WAVE STRUCTURE; MU-M AB An important goal of the study of atmospheres of planets is to provide an understanding of the relationship and interaction among phenomena occurring at different altitude and pressure regions and the effects of external influences on these phenomena. To probe multiple pressure regimes in general requires measurements in different spectral regions and with a wide range of spectral resolutions. This presents formidable technical challenges. To directly probe phenomena in the upper neutral atmosphere (pressures <30 mbar) is particularly difficult. Much of the information on local chemistry and physics is contained in the near Doppler profiles of infrared molecular lines formed in these regions and spectral resolving powers lambda/DELTAlambda > 10(6) are required to adequately measure the lineshapes. The very high spectral resolution technique of infrared heterodyne spectroscopy capable of making such line measurements is briefly described. Several investigations are described to illustrate the range of phenomena that can be studied and the unique physical and chemical parameters that can be retrieved. These investigations include direct measurement of global thermospheric circulation on Venus using Doppler shifts of nonthermal CO2 emission lines near 10 mum; the study of Jupiter's deep interior utilizing spectroscopy of H-2 quadrupole lines (17 and 28.2 mum) formed in the stratosphere; the evaluation of photochemical processes which determine the composition of Mars and the outer planets by retrieving constituent abundances (O3 near 9.5 mum on Mars and hydrocarbons on Jupiter and Neptune); and the determination of the compositional and thermal structure in Jupiter's auroral region using line profiles of auroral ethylene (C2H4) and ethane (C2H6) emission near 10.5 and 12 mum. The value of multispectral and temporal observations for more comprehensive studies of atmospheric phenomena and the internal and external processes driving them are also discussed. RP KOSTIUK, T (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 693,GREENBELT,MD 20771, USA. RI Kostiuk, Theodor/A-3077-2014 NR 95 TC 32 Z9 32 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 243 EP 266 DI 10.1016/1350-4495(94)90084-1 PG 24 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100017 ER PT J AU MAFFEI, B PAJOT, F PHILLIPS, TG BENFORD, D CAUX, E GISPERT, R HALVERSON, N HUNTER, T JEGOUDEZ, G JOSSE, M LAMARRE, JM LEPELTIER, JP MOSELEY, H ORIGNE, A PETUCHOWSKY, S RABOTTIN, M RENAULT, JC RIOUX, C SERABYN, G WANG, N AF MAFFEI, B PAJOT, F PHILLIPS, TG BENFORD, D CAUX, E GISPERT, R HALVERSON, N HUNTER, T JEGOUDEZ, G JOSSE, M LAMARRE, JM LEPELTIER, JP MOSELEY, H ORIGNE, A PETUCHOWSKY, S RABOTTIN, M RENAULT, JC RIOUX, C SERABYN, G WANG, N TI A MEDIUM RESOLUTION GROUND-BASED SUBMILLIMETER SPECTROMETER SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Conference on Infrared Physics (CIRPS 5): Topical Conference on Infrared Astrophysics CY JUN 20-25, 1993 CL CTR STEFANO FRANSCINI, MONTE VERITA, ASCONA, SWITZERLAND SP SWISS SOC ASTROPHYS & ASTRON, SWISS PHYS SOC, SWISS ACAD NAT SCI, COMM SPACE RES HO CTR STEFANO FRANSCINI, MONTE VERITA ID DISTANT RADIO GALAXIES; SPECTROSCOPY; REDSHIFT; EMISSION; CLOUDS; LINE AB We present a submillimeter spectrometer based on a cooled scanning Fabry-Perot working at 1.4 K temperature and using gold inductive grids deposited on quartz substrates as reflective faces. The detection is achieved by an array of 24 silicon bolometers cooled at 0.1 K by an adiabatic demagnetization refrigerator. This spectrometer will be operated at the focus of the 10 m ground based antenna of the Caltech Submillimeter Observatory and is the precursor of balloon borne or space instruments. It is mainly dedicated to high redshift galaxy observations, and especially to the CII line (158 mum) studies in these objects. The observations will be carried out in two atmospheric windows centered on 350 and 450 mum, and the spectrometer will be able to detect galaxies at a redshift of about 1-2 with a FIR luminosity of a few 10(12) L.. C1 CALTECH,GW DOWNS LAB PHYS,PASADENA,CA 91125. CESR,F-31055 TOULOUSE,FRANCE. IRM,PE,DT,CEA,CESTA,F-33114 LE BARP,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GSFC,GREENBELT,MD 20771. LAS,F-13012 MARSEILLE,FRANCE. IAP,F-75014 PARIS,FRANCE. RP MAFFEI, B (reprint author), UNIV PARIS 11,CNRS,IAS,BATIMENT 121,F-91405 ORSAY,FRANCE. RI Benford, Dominic/D-4760-2012; Moseley, Harvey/D-5069-2012 OI Benford, Dominic/0000-0002-9884-4206; NR 20 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 321 EP 329 DI 10.1016/1350-4495(94)90090-6 PG 9 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100023 ER PT J AU MATHER, JC AF MATHER, JC TI INFRARED MEASUREMENTS FROM THE COSMIC BACKGROUND EXPLORER (COBE) SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Conference on Infrared Physics (CIRPS 5): Topical Conference on Infrared Astrophysics CY JUN 20-25, 1993 CL CTR STEFANO FRANSCINI, MONTE VERITA, ASCONA, SWITZERLAND SP SWISS SOC ASTROPHYS & ASTRON, SWISS PHYS SOC, SWISS ACAD NAT SCI, COMM SPACE RES HO CTR STEFANO FRANSCINI, MONTE VERITA ID DIFFERENTIAL MICROWAVE RADIOMETERS; DESIGN; ANISOTROPY; EMISSION; DEWAR AB The Cosmic Background Explorer (COBE) satellite was developed by NASA's Goddard Space Flight Center to measure the diffuse IR and microwave radiation from the early universe, to the limits set by our astrophysical environment. It was launched 18 November 1989 and carried three instruments, a FIR Absolute Spectrophotometer (FIRAS) to compare the cosmic microwave background radiation with a precise blackbody, a Differential Microwave Radiometer (DMR) to map the cosmic radiation precisely, and a Diffuse Infrared Background Experiment (DIRBE) to search for the accumulated light of primeval galaxies. The cosmic microwave background radiation spectrum was measured 1000 times more precisely than was possible before the COBE launch. The microwave background was found to have an intrinsic anisotropy for the first time, at a level of a part in 10(5) with a smoothing of 10-degrees. A comprehensive set of absolutely calibrated IR sky maps has been acquired to search for the cosmic IR background. RP MATHER, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 685,GREENBELT,MD 20771, USA. NR 52 TC 2 Z9 2 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 331 EP 336 DI 10.1016/1350-4495(94)90091-4 PG 6 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100024 ER PT J AU WERNER, MW AF WERNER, MW TI THE ATLAS SIRTF SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article; Proceedings Paper CT 5th International Conference on Infrared Physics (CIRPS 5): Topical Conference on Infrared Astrophysics CY JUN 20-25, 1993 CL CTR STEFANO FRANSCINI, MONTE VERITA, ASCONA, SWITZERLAND SP SWISS SOC ASTROPHYS & ASTRON, SWISS PHYS SOC, SWISS ACAD NAT SCI, COMM SPACE RES HO CTR STEFANO FRANSCINI, MONTE VERITA ID GALAXY; SEARCH; COUNTS AB This paper describes the status of NASA's Space Infrared Telescope Facility (SIRTF) program. SIRTF will be a cryogenically cooled observatory for infrared astronomy from space and is planned for launch early in the next decade, We summarize a newly modified SIRTF baseline, which is to be launched into a heliocentric orbit by an Atlas Ilas rocket, and provide an overview of SIRTF's scientific programs. RP WERNER, MW (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 35 TC 17 Z9 17 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD MAR-APR PY 1994 VL 35 IS 2-3 BP 539 EP 550 DI 10.1016/1350-4495(94)90109-0 PG 12 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA NK781 UT WOS:A1994NK78100042 ER PT J AU DODD, DE STUART, BO ROTHENBERG, SJ KERSHAW, MA MANN, PC JAMES, JT LAM, CW AF DODD, DE STUART, BO ROTHENBERG, SJ KERSHAW, MA MANN, PC JAMES, JT LAM, CW TI ACUTE, 2-WEEK, AND 13-WEEK INHALATION TOXICITY STUDIES ON DIMETHYLETHOXYSILANE VAPOR IN FISCHER-344 RATS SO INHALATION TOXICOLOGY LA English DT Article AB Dimethylethoxysilane (DMES), a volatile liquid, is used by NASA to waterproof the heat-protective silica tiles and blankets on the Space Shuttle. Acute, 2-wk, and 13-wk inhalation exposures to DMES vapor were conducted in male and female Fischer 344 rats. In the acute study, rats were exposed to 4000, 2000, 1000, 500, or 0 (control) ppm DMES for 4 h and observed for 14 days. There were no deaths. Narcosis and ataxia were observed in rats of the two highest concentrations only. These signs disappeared within I h following exposure. There were no DMES-related gross or microscopic tissue lesions in rats of all exposure groups. In the 2-wk study, rats were exposed for 6 h/day, 5 days/wk to 3000, 1000, 300, 100, or 0 ppm DMES. During exposure, narcosis was observed in rats of the 3000 and 1000 ppm groups. There was a mild decrease in body weight gain in rats of the 3000 ppm group. A decrease in platelet count, an increase in bile acids, and reduced weights of the thymus, testis, and liver were observed in rats of the 3000 ppm group. Microscopically, hypospermatogenesis and spermatid giant cells were observed in the seminiferous tubules of the testes of rats exposed to 3000 ppm DMES. In the 13-wk study, rats were exposed 6 h/day, 5 days/wk to 2000, 600, 160, 40, or 0 ppm DMES. During exposure, rats of the 2000 ppm group exhibited mild narcosis and loss of startle reflex. Recovery from these central nervous system signs was rapid. Body weights were mildly decreased for rats of the 2000 ppm group. There were no exposure-related effects in hematology, serum chemistry, or urinalysis. Female rats of the 2000 ppm group had delayed estrous cycles (6 days compared to 5 days in control rats). Noteworthy organ weight changes in rats of the 2000 ppm group included decreases in thymus, liver, and testicular weights; however, pathologic lesions were observed in the testes only. Sperm motility, epididymal sperm count, and testicular spermatid count were dramatically reduced. Microscopic lesions included degeneration of the seminiferous tubular cells, pyknosis or absence of germ cells, and hypospermia in the epididymis. Rats of the 600 ppm group had a slight decrease in thymic weight and a transient decrease in body weight. Results of the acute, 2-wk, and 13-wk inhalation studies indicate DMES concentrations of 1000 ppm and higher produce narcosis that rapidly disappears following exposure. Repeated exposure of rats to DMES at either 3000 ppm for 2 wk or 2000 ppm for 13 wk caused testicular atrophy and hypospermia in male rats. Female rats exposed to 2000 ppm for 13 wk had delayed estrous cycles. Toxicological effects in rats of the 600 ppm group were minimal and equivocal. The 160 ppm concentration was a no-observable-effect level (NOEL) for 73 wk of exposure to DMES. C1 BROOKHAVEN NATL LAB,NEW YORK,NY. EXPTL PATHOL LABS INC,RES TRIANGLE PK,NC. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. KRUG LIFE SCI INC,HOUSTON,TX. RP DODD, DE (reprint author), MANTECH ENVIRONM TECHNOL INC,POB 31009,DAYTON,OH 45437, USA. NR 21 TC 4 Z9 4 U1 0 U2 0 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0895-8378 J9 INHAL TOXICOL JI Inhal. Toxicol. PD MAR-APR PY 1994 VL 6 IS 2 BP 151 EP 166 DI 10.3109/08958379409029702 PG 16 WC Toxicology SC Toxicology GA NJ195 UT WOS:A1994NJ19500005 PM 11537968 ER PT J AU LUCHIK, TS KWACK, EY AARON, KM SHAKKOTTAI, P BACK, LH AF LUCHIK, TS KWACK, EY AARON, KM SHAKKOTTAI, P BACK, LH TI MULTIPHASE MIXING OF LIQUID CRYOGENS IN THE SIMULATION OF EXPLOSION HAZARDS SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article AB Experiments simulating mixing of liquid oxygen (LO2) and liquid hydrogen (LH2) have been performed. The non-reactive mixtures were obtained by injecting jets of the oxidizer or simulant into a pool of the fuel or simulant. Three fluid combinations were tested: LO2 into liquid helium (LHe), liquid nitrogen (LN2) into LHe and LN2 into LH2. Experimental observations included flash X-ray and high speed video imaging, hot film anemometry, and thermocouple and diode thermometry. Results showed that the jet fluid stays coherent throughout the mixing process and that peak boiling of the pool fluid occurs shortly after jet impingement. Estimates of bulk density indicate a smaller range of variation than is currently being used for explosive yield calculations. RP LUCHIK, TS (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 12 TC 1 Z9 1 U1 0 U2 4 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 MAR PY 1994 VL 37 SU 1 BP 123 EP 132 DI 10.1016/0017-9310(94)90016-7 PG 10 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA NE248 UT WOS:A1994NE24800015 ER PT J AU SIEGEL, R SPUCKLER, CM AF SIEGEL, R SPUCKLER, CM TI APPROXIMATE SOLUTION METHODS FOR SPECTRAL RADIATIVE-TRANSFER IN HIGH REFRACTIVE-INDEX LAYERS SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID BEHAVIOR AB Some ceramic materials for high temperature applications are partially transparent for radiative transfer. The refractive indices of these materials can be substantially greater than one which influences internal radiative emission and reflections. Heat transfer behavior of single and laminated layers has been obtained in the literature by numerical solutions of the radiative transfer equations coupled with heat conduction and heating at the boundaries by convection and radiation. Two-flux and diffusion methods are investigated here to obtain approximate solutions using a simpler formulation than required for exact numerical solutions. Isotropic scattering is included. The two-flux method for a single layer yields excellent results for gray and two band spectral calculations. The diffusion method yields a good approximation for spectral behavior in laminated multiple layers if the overall optical thickness is larger than about ten. A hybrid spectral model is developed using the two-flux method in the optically thin bands, and radiative diffusion in bands that are optically thick. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP SIEGEL, R (reprint author), NASA,LEWIS RES CTR,RES ACAD,CLEVELAND,OH 44135, USA. NR 10 TC 36 Z9 38 U1 1 U2 5 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 MAR PY 1994 VL 37 SU 1 BP 403 EP 413 DI 10.1016/0017-9310(94)90040-X PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA NE248 UT WOS:A1994NE24800039 ER PT J AU KOOI, JW WALKER, CK LEDUC, HG SCHAFFER, PL HUNTER, TR BENFORD, DJ PHILLIPS, TG AF KOOI, JW WALKER, CK LEDUC, HG SCHAFFER, PL HUNTER, TR BENFORD, DJ PHILLIPS, TG TI A LOW-NOISE 665 GHZ SIS QUASI-PARTICLE WAVE-GUIDE RECEIVER SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article ID RADIO ASTRONOMY AB We report recent results on a 565-690 GHz SIS heterodyne receiver employing a 0.36mum2 Nb/AlO(x)/Nb SIS tunnel junction with high quality circular non-contacting backshort and E-plane tuners in a full height waveguide mount. No resonant tuning structures have been incorporated in the junction design at this time, even though such structures are expected to help the performance of the receiver. The receiver operates to at least the pp frequency of Niobium, almost-equal-to 680 GHz. Typical receiver noise temperatures from 565-690 GHz range from 160K to 230K with a best value of 185K DSB at 648 GHz. With the mixer cooled from 4.3K to 2K the measured receiver noise temperatures decreased by approximately 15%, giving roughly 180K DSB from 660 to 680 GHz. The receiver has a full 1 GHz IF passband and has been successfully installed at the Caltech Submillimeter Observatory in Hawaii. C1 UNIV ARIZONA,TUCSON,AZ 85721. JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP KOOI, JW (reprint author), CALTECH,CALTECH SUBMILLIMETER OBSERV,DIV PHYS MATH & ASTRON,PASADENA,CA 91125, USA. RI Benford, Dominic/D-4760-2012 OI Benford, Dominic/0000-0002-9884-4206 NR 23 TC 23 Z9 23 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD MAR PY 1994 VL 15 IS 3 BP 477 EP 492 DI 10.1007/BF02096231 PG 16 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA NB258 UT WOS:A1994NB25800002 ER PT J AU WU, TK AF WU, TK TI GREENS-FUNCTION FOR ARBITRARILY-SHAPED DIELECTRIC BODIES OF REVOLUTION SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article AB In this paper, a solution is developed to calculate the electric field at one point in space due to an electric dipole exciting an arbitrarily shaped dielectric body of revolution (BOR). Specifically, the electric field is determined from the solution of coupled surface integral equations (SIE) for the induced surface electric and magnetic currents on the dielectric body excited by an elementary electric current dipole source. Both the interior and exterior fields to the dielectric BOR may be accurately evaluated via this approach. For a highly lossy dielectric body, the numerical Green's function is also obtainable from an approximate integral equation (AIE) based on a surface boundary condition. If this equation is solved by the method of moments, significant numerical efficiency over SIE is realized. Numerical results obtained by both SIE and AIE approaches agree with the exact solution for the special case of a dielectric sphere. With this numerical Green's function, the complicated radiation and scattering problems in the presence of an arbitrarily shaped dielectric BOR are readily solvable by the method of moments. RP WU, TK (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 11 TC 0 Z9 0 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD MAR PY 1994 VL 15 IS 3 BP 567 EP 577 DI 10.1007/BF02096239 PG 11 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA NB258 UT WOS:A1994NB25800010 ER PT J AU KOITER, WT ELISHAKOFF, I LI, YW STARNES, JH AF KOITER, WT ELISHAKOFF, I LI, YW STARNES, JH TI BUCKLING OF AN AXIALLY COMPRESSED CYLINDRICAL-SHELL OF VARIABLE THICKNESS SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article AB This paper focuses on the buckling of cylindrical shells with small thickness variations. Two important cases of thickness variation pattern are considered. Asymptotic formulas up to the second order of the thickness variation parameter epsilon are derived by the combination of the perturbation and weighted residual methods. The expressions obtained in this study reduce to Koiter's formulas, when only the first-order term of the thickness variation parameter is retained in the analysis. Results from the asymptotic formulas are compared with those obtained through the purely numerical techniques of the finite difference method and the shooting method. C1 FLORIDA ATLANTIC UNIV,CTR APPL STOCHAST RES,BOCA RATON,FL 33431. NASA,LANGLEY RES CTR,HAMPTON,VA 23664. RP KOITER, WT (reprint author), DELFT UNIV TECHNOL,ENGN MECH LAB,2600 GA DELFT,NETHERLANDS. NR 7 TC 39 Z9 39 U1 0 U2 12 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 MAR PY 1994 VL 31 IS 6 BP 797 EP 805 DI 10.1016/0020-7683(94)90078-7 PG 9 WC Mechanics SC Mechanics GA NC071 UT WOS:A1994NC07100004 ER PT J AU LAUNIUS, RD AF LAUNIUS, RD TI THE SPUTNIK CHALLENGE - EISENHOWER RESPONSE TO THE SOVIET SATELLITE - DIVINE,RA SO ISIS LA English DT Book Review RP LAUNIUS, RD (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0021-1753 J9 ISIS JI Isis PD MAR PY 1994 VL 85 IS 1 BP 173 EP 174 DI 10.1086/356780 PG 2 WC History & Philosophy Of Science SC History & Philosophy of Science GA NB786 UT WOS:A1994NB78600066 ER PT J AU SHIN, J BERKOWITZ, B CHEN, HH CEBECI, T AF SHIN, J BERKOWITZ, B CHEN, HH CEBECI, T TI PREDICTION OF ICE SHAPES AND THEIR EFFECT ON AIRFOIL DRAG SO JOURNAL OF AIRCRAFT LA English DT Article AB Calculation of ice shapes and the resulting drag increases are presented for a NACA 0012 airfoil. The calculations were made using a combination of modified LEWICE and interactive boundary-layer codes for a wide range of values of parameters such as airspeed and temperature, the droplet size and liquid water content of the cloud, and the angle of attack of the airfoil. Based on experimental data, an improved correlation of equivalent sand-grain roughness was developed. Calculated ice shapes are in good agreement with experimental data for rime ice, but some differences are shown between predictions and experimental data for glaze ice. Calculated drag coefficients generally follow trends shown by the experimental data. RP SHIN, J (reprint author), NASA,DIV PROPULS SYST,ICING & CRYOGEN TECHNOL BRANCH,CLEVELAND,OH 44135, USA. NR 0 TC 9 Z9 12 U1 0 U2 3 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 MAR-APR PY 1994 VL 31 IS 2 BP 263 EP 270 DI 10.2514/3.46483 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700003 ER PT J AU ALKHALIL, KM KEITH, TG DEWITT, KJ AF ALKHALIL, KM KEITH, TG DEWITT, KJ TI DEVELOPMENT OF AN IMPROVED MODEL FOR RUNBACK WATER ON AIRCRAFT SURFACES SO JOURNAL OF AIRCRAFT LA English DT Article AB A computer simulation for ''running wet'' and evaporative aircraft anti-icing systems is developed. The model is based on the analysis of the liquid water film which forms in the regions of direct impingement, and then breaks up near the impingement limits into rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted using a stability analysis theory and the laws of mass and energy conservation. The solid structure is modeled as a multiple layer wall. The anti-icing system modeled is of the thermal type utilizing hot air and/or electrical heating elements embedded within the wall layers. Experimental observations revealing some of the basic physics of the water flow on the surface are presented. Detailed qualitative documentation of the tests are given. Several numerical examples are considered, and the effect of some of the involved parameters on the system performance are investigated. RP ALKHALIL, KM (reprint author), NASA,LEWIS RES CTR,NATL RES COUNCIL,CLEVELAND,OH 44135, USA. NR 0 TC 11 Z9 13 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 271 EP 278 DI 10.2514/3.46484 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700004 ER PT J AU SMITH, BE POPPEN, WA LYE, JD AF SMITH, BE POPPEN, WA LYE, JD TI PROPULSION-INDUCED AERODYNAMIC EFFECTS MEASURED WITH A FULL-SCALE STOVL MODEL SO JOURNAL OF AIRCRAFT LA English DT Article AB Propulsion-induced aerodynamic interference effects are presented for a full-scale, powered, STOVL righter aircraft model. The ejector-lift/vectored thrust configuration, designated the E-7A, was tested at low speed in the 40- by 80- and 80- by 120-ft wind tunnels of the National Full-Scale Aerodynamics Complex located at NASA Ames Research Center. Aerodynamic effects on vehicle lift, drag, and pitching moment are presented over a range of effective velocities for simultaneous operation of all lifting jets. The jet/airframe interactions for separate operation of the lifting ejector system and vectorable ventral nozzle are also presented. Ejector and engine inlet momentum effects were fully simulated in these full-scale, powered tests. The jet thrust vector angle of the ventral nozzle was varied to simulate transition from hover to wingborne flight modes. When the lifting ejector system and ventral nozzle are operated simultaneously, the induced effects on lift decrease as the thrust vector angle of the ventral nozzle approaches the horizontal. A negative increment in drag is produced over a narrow portion of the transition speed range when the ejectors and ventral nozzle are operated together. Aerodynamic induced effects of the ejector system measured at full-scale compare well with the small-scale data. Changes in lift and pitching moment due to ventral nozzle operation are smaller at full scale. RP SMITH, BE (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 306 EP 313 DI 10.2514/3.46488 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700008 ER PT J AU TU, EL AF TU, EL TI VORTEX-WING INTERACTION OF A CLOSE-COUPLED CANARD CONFIGURATION SO JOURNAL OF AIRCRAFT LA English DT Article AB The thin-layer Navier-Stokes equations are solved numerically to investigate the effects of canard vertical position on a close-coupled, canard-wing-body configuration at a transonic Mach number of 0.90 and angles of attack ranging from -2 to 12 deg. Canard-wing interactions are investigated for the canard positioned above, coplanar with, and below the wing (high-, mid- and low-canard positions, respectively). The computational results show favorable canard-wing interactions for the high- and midcanard configurations. The unfavorable lift and drag characteristics for the low-canard configuration are examined by analyses of the low-canard flowfield structure and found to be directly attributed to the interaction between the canard vortex and the wing surface. At relatively low angles of attack, the low-canard vortex passes under the wing surface and induces low pressures on the wing lower surface. As angle of attack is increased, the low-canard vortex impacts the wing surface and is split into two distinct vortices. RP TU, EL (reprint author), NASA,AMES RES CTR,COMPUTAT AEROSCI BRANCH,M-S 2581,MOFFETT FIELD,CA 94035, USA. NR 0 TC 6 Z9 6 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 MAR-APR PY 1994 VL 31 IS 2 BP 314 EP 321 DI 10.2514/3.46489 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700009 ER PT J AU BARTHELEMY, JFM WRENN, GA DOVI, AR COEN, PG HALL, LE AF BARTHELEMY, JFM WRENN, GA DOVI, AR COEN, PG HALL, LE TI SUPERSONIC TRANSPORT WING MINIMUM WEIGHT DESIGN INTEGRATING AERODYNANAMICS AND STRUCTURES SO JOURNAL OF AIRCRAFT LA English DT Article AB An approach is presented for determining the minimum weight design of aircraft wing models which takes into consideration aerodynamics-structure coupling when calculating both zeroth-order information needed for analysis and first-order information needed for optimization. When performing sensitivity analysis, coupling is accounted for by using a generalized sensitivity formulation. The results presented show that the aeroelastic effects are calculated properly and noticeably reduce constraint approximation errors. However, for the particular example selected, the error introduced by ignoring aeroelastic effects are not sufficient to significantly affect the convergence of the optimization process. Trade studies are reported that consider different structural materials, internal spar layouts, and panel buckling lengths. For the formulation, model, and materials used in this study, an advanced aluminum material produced the lightest design while satisfying the problem constraints. Also, shorter panel buckling lengths resulted in lower weights by permitting smaller panel thicknesses and generally, unloading the wing skins and loading the spar caps. Finally, straight spars required slightly lower wing weights than angled spars. RP BARTHELEMY, JFM (reprint author), NASA,LANGLEY RES CTR,AEROELAST ANAL & OPTIMIZAT BRANCH,DIV STRUCT DYNAM,M-S 246,HAMPTON,VA 23666, USA. NR 0 TC 13 Z9 13 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 330 EP 338 DI 10.2514/3.46491 PG 9 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700011 ER PT J AU ZELENKA, RE AF ZELENKA, RE TI DESIGN AND ANALYSIS OF A KALMAN FILTER FOR TERRAIN-REFERENCED POSITIONING AND GUIDANCE SO JOURNAL OF AIRCRAFT LA English DT Article AB Avionic systems that depend on digitized terrain elevation data for guidance generation or navigational reference require accurate absolute and relative distance measurements to the terrain, especially as they approach lower altitudes. This is particularly exacting in low-altitude helicopter missions, where aggressive terrain hugging maneuvering create minimal horizontal and vertical clearances and demand precise terrain positioning. Sole reliance on airborne precision navigation and stored terrain elevation data for above-ground-level (AGL) positioning severely limits the operational altitude of such systems. A Kalman filter is presented which blends radar altimeter returns, precision navigation, and stored terrain elevation data for AGL positioning. The filter is evaluated using low-altitude helicopter flight test data acquired over moderately rugged terrain. The proposed Kalman filter is found to remove large disparities in predicted AGL altitude (i.e., from airborne navigation and terrain elevation data) in the presence of measurement anomalies and dropouts. Previous work suggested a minimum clearance altitude of 220-ft AGL for a near-terrain guidance system; integration of a radar altimeter suggests operation of that system to 50 ft, subject to obstacle-avoidance limitations. RP ZELENKA, RE (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 4 Z9 4 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 MAR-APR PY 1994 VL 31 IS 2 BP 339 EP 344 DI 10.2514/3.46492 PG 6 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700012 ER PT J AU BAUER, SXS HEMSCH, MJ AF BAUER, SXS HEMSCH, MJ TI ALLEVIATION OF SIDE FORCE ON TANGENT-OGIVE FOREBODIES USING PASSIVE POROSITY SO JOURNAL OF AIRCRAFT LA English DT Article AB An experimental investigation to determine the effectiveness of passive porosity for alleviating side forces on forebodies was conducted in the NASA Langley Research Center 7-ft by 10-ft high-speed wind tunnel. Force, moment, and surface pressure data were obtained on solid and porous (22% porosity, 0.020-in. hole diam) tangent-ogive forebodies of fineness ratios 2.5 and 5.0. The solid forebodies were tested with transition grit to simulate fully turbulent conditions, and without transition grit to simulate free transition conditions. The extent of porosity on the forebodies was varied to determine the extent of porosity needed to alleviate side forces. Static longitudinal and lateral-directional stability and surface pressure data were obtained at Mach numbers of 0.2, 0.5, and 0.8, angles of attack from -5 to 45 deg, and roll angles from -90 to 180 deg. The solid forebodies exhibited large asymmetric pressure loads at moderate to high angles of attack causing large side forces and yawing moments; the transition grit had minimal effect on the asymmetric characteristics, but had a large effect on the longitudinal characteristics. The porous forebodies exhibited no significant side forces or yawing moments at any angle of attack tested. RP BAUER, SXS (reprint author), NASA,LANGLEY RES CTR,SUPERSON HYPERSON AERODYNAM BRANCH,DIV APPL AERODYNAM,HAMPTON,VA 23665, USA. NR 0 TC 4 Z9 4 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 354 EP 361 DI 10.2514/3.46494 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700014 ER PT J AU JEGLEY, DC AF JEGLEY, DC TI STUDY OF STRUCTURALLY EFFICIENT GRAPHITE-THERMOPLASTIC TRAPEZOIDAL-CORRUGATION SANDWICH AND SEMISANDWICH PANELS SO JOURNAL OF AIRCRAFT LA English DT Article AB The structural efficiency of compression-loaded trapezoidal-corrugation sandwich and semisandwich composite panels is studied to determine their weight savings potential. Sandwich panels with two identical face sheets and a trapezoidal corrugated core between them, and semisandwich panels with a corrugation attached to a single skin are considered. An optimization code is used to rind the minimum weight designs for critical compressive load levels ranging from 3000 to 24,000 lb/in. Graphite-thermoplastic panels based on the optimal minimum weight designs were fabricated and tested. A finite-element analysis of several test specimens was also conducted. The results of the optimization study, the finite element analysis, and the experiments are presented. RP JEGLEY, DC (reprint author), NASA,LANGLEY RES CTR,DIV STRUC MECH,AIRCRAFT STRUCT BRANCH,M-S 190,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 2 U2 2 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 MAR-APR PY 1994 VL 31 IS 2 BP 411 EP 418 DI 10.2514/3.46501 PG 8 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700021 ER PT J AU VORACEK, DF CLARKE, R AF VORACEK, DF CLARKE, R TI BUFFET-INDUCED STRUCTURAL FLIGHT-CONTROL SYSTEM INTERACTION OF THE X-29A AIRCRAFT SO JOURNAL OF AIRCRAFT LA English DT Note RP VORACEK, DF (reprint author), NASA,DRYDEN FLIGHT RES FACIL,STRUCT DYNAM SECT XRDV,DYNAM & CONTROLS BRANCH,POB 273,EDWARDS AFB,CA 93523, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 441 EP 442 DI 10.2514/3.46505 PG 2 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700025 ER PT J AU PHILLIPS, WH AF PHILLIPS, WH TI EFFECTS OF MODEL SCALE ON FLIGHT CHARACTERISTICS AND DESIGN PARAMETERS SO JOURNAL OF AIRCRAFT LA English DT Note RP PHILLIPS, WH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1994 VL 31 IS 2 BP 454 EP 457 DI 10.2514/3.46511 PG 4 WC Engineering, Aerospace SC Engineering GA NF087 UT WOS:A1994NF08700031 ER PT J AU LISTON, GE SUD, YC WOOD, EF AF LISTON, GE SUD, YC WOOD, EF TI EVALUATING GCM LAND-SURFACE HYDROLOGY PARAMETERIZATIONS BY COMPUTING RIVER DISCHARGES USING A RUNOFF ROUTING MODEL - APPLICATION TO THE MISSISSIPPI BASIN SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID GENERAL-CIRCULATION MODELS; BIOSPHERE MODEL AB To relate general circulation model (GCM) hydrologic output to readily available river hydrographic data, a runoff routing scheme that routes gridded runoffs through regional- or continental-scale river drainage basins is developed. By following the basin overland flow paths, the routing model generates river discharge hydrographs that can be compared to observed river discharges, thus allowing an analysis of the GCM representation of monthly, seasonal, and annual water balances over large regions. The runoff routing model consists of two linear reservoirs, a surface reservoir and a groundwater reservoir, which store and transport water. The water transport mechanisms operating within these two reservoirs are differentiated by their time scales; the groundwater reservoir transports water much more slowly than the surface reservoir. The groundwater reservoir feeds the corresponding surface store, and the surface stores are connected via the river network. The routing model is implemented over the GEWEX (Global Energy and Water Cycle Experiment) Continental-Scale International Project Mississippi River basin on a rectangular grid of 2-degrees x 2.5-degrees. Two land surface hydrology parameterizations provide the gridded runoff data required to run the runoff routing scheme: the variable infiltration capacity model, and the soil moisture component of the simple biosphere model. These parameterizations are driven with 4-degrees x 5-degrees gridded climatological potential evapotranspiration and 1979 First GARP (Global Atmospheric Research Program) Global Experiment precipitation. These investigations have quantified the importance of physically realistic soil moisture holding capacities, evaporation parameters, and runoff mechanisms in land surface hydrology formulations. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. PRINCETON UNIV,WATER RESOURCES PROGRAM,PRINCETON,NJ 08544. RP LISTON, GE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CLIMATE & RADIAT BRANCH,MAIL CODE 913,GREENBELT,MD 20771, USA. NR 26 TC 84 Z9 89 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAR PY 1994 VL 33 IS 3 BP 394 EP 405 DI 10.1175/1520-0450(1994)033<0394:EGLSHP>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA MZ789 UT WOS:A1994MZ78900008 ER PT J AU KATZ, S ROTH, M GOLBEN, J VLASSE, M AF KATZ, S ROTH, M GOLBEN, J VLASSE, M TI LOW-TEMPERATURE THERMOLUMINESCENCE OF CUPRATE HIGH-TEMPERATURE SUPERCONDUCTORS SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID THERMALLY STIMULATED LUMINESCENCE; HIGH-TC SUPERCONDUCTORS; YBA2CU3O7-DELTA; OXIDES AB The thermoluminescence (TL) of three different high-temperature superconducting materials, namely ErBaCuO, YbBaCuO, and (Bi,Pb)SrCaCuO, has been measured after x irradiation at 20 K. This comparative low-temperature TL investigation has revealed a close similarity in the structure of the glow curves for all three compounds in the 20-300 K temperature range. Strongest glow peaks are shown to appear below the superconducting transition temperature. The origin of the various glow peaks is discussed in terms of radiative recombination of thermally released holes with trapped electron centers. The model is supported by further TL measurements of the ErBaCuO compound, thermally treated, in reducing and oxidizing atmospheres. It is demonstrated that the TL intensity is closely related to the oxygen stoichiometry of the material, namely, the oxygen vacancies. C1 HEBREW UNIV JERUSALEM,SCH APPL SCI,IL-91904 JERUSALEM,ISRAEL. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP KATZ, S (reprint author), HEBREW UNIV JERUSALEM,RACAH INST PHYS,IL-91904 JERUSALEM,ISRAEL. NR 17 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1994 VL 75 IS 5 BP 2712 EP 2714 DI 10.1063/1.356202 PG 3 WC Physics, Applied SC Physics GA MY995 UT WOS:A1994MY99500064 ER PT J AU ROSCH, W FRIPP, A DEBNAM, W PENDERGRASS, TK AF ROSCH, W FRIPP, A DEBNAM, W PENDERGRASS, TK TI HEAT-TRANSFER MEASUREMENTS IN THE BRIDGMAN CONFIGURATION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 9th American Conference on Crystal Growth (ACCG-9) CY AUG 01-06, 1993 CL BALTIMORE, MD SP AMER ASSOC CRYSTAL GROWTH, USAF OFF SPONSORED REG, NASA, NATL SCI FDN, AESAR ALFA JOHNSON MATTHEY, LITTON SYST, AIRTRON DIV, APPL TECHNOL INC, CERES CORP, CLEVELAND CRYSTALS, CRYSTAL ASSOC INC, CRYSTAL TECHNOL INC, CRYSTALLOD INC, DELTRONIC CRYSTAL IND, ENGELHARD CORP, JOHNSON MATTHEY ELECTR, JOHNSON MATTHEY INC, LASER DIODE INC, LIGHTNING OPT, MR SEMICON INC, SAINT GOBAIN NORTON, SENSORS UNLIMITED INC, STRUERS LOGITECH, SUMITOMO ELECT CORP, VIRGO OPT AB A heat transfer measuring device was developed to help characterize a vertical Bridgman furnace. The actively heated device, the heat transfer sample HTX, measures the temperature difference created between it and the furnace wall as a function of input power. This allows the heat transfer coefficient to be measured without having to know the physical properties of the sample, the ambient gas, or the furnace. However, if some of these physical properties are known, then the HTX can be used to determine others. Heat transfer measurements were made under a variety of conditions. The convective heat loss was varied by making measurements in air, argon, helium, and vacuum environments. The radiative heat loss was varied by using fused silica, oxidized inconel, and platinum foil sleeves placed over the HTX heater. A convection coefficient for air and the emissivities of the different sleeves were determined. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. UNIV VIRGINIA,CHARLOTTESVILLE,VA 22903. RP ROSCH, W (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 5 TC 4 Z9 4 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 MAR PY 1994 VL 137 IS 1-2 BP 54 EP 58 DI 10.1016/0022-0248(94)91246-7 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA NC995 UT WOS:A1994NC99500010 ER PT J AU PRICE, MW ANDREWS, RN SU, CH LEHOCZKY, SL SZOFRAN, FR AF PRICE, MW ANDREWS, RN SU, CH LEHOCZKY, SL SZOFRAN, FR TI THE EFFECT OF A TRANSVERSE MAGNETIC-FIELD ON THE MICROSTRUCTURE OF DIRECTIONALLY SOLIDIFIED CDTE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 9th American Conference on Crystal Growth (ACCG-9) CY AUG 01-06, 1993 CL BALTIMORE, MD SP AMER ASSOC CRYSTAL GROWTH, USAF OFF SPONSORED REG, NASA, NATL SCI FDN, AESAR ALFA JOHNSON MATTHEY, LITTON SYST, AIRTRON DIV, APPL TECHNOL INC, CERES CORP, CLEVELAND CRYSTALS, CRYSTAL ASSOC INC, CRYSTAL TECHNOL INC, CRYSTALLOD INC, DELTRONIC CRYSTAL IND, ENGELHARD CORP, JOHNSON MATTHEY ELECTR, JOHNSON MATTHEY INC, LASER DIODE INC, LIGHTNING OPT, MR SEMICON INC, SAINT GOBAIN NORTON, SENSORS UNLIMITED INC, STRUERS LOGITECH, SUMITOMO ELECT CORP, VIRGO OPT ID HGCDTE AB The purpose of this study was to examine several microstructural features in Bridgman-grown CdTe and determine whether the use of a transverse, 4.6 kG magnetic field during solidification had any effect on these features. Any variation in these microstructural features due to the use of the magnetic field could be attributed to changes in the convective state of the melt and the resulting disruption or stabilization of the solid-liquid interface. In order to accomplish this objective, samples of CdTe were directionally solidified by the vertical Bridgman-Stock-barger method and a static magnetic field of 4.6 kG was applied transverse to the growth direction during the solidification of selected samples. The microstructural features examined included the preferred crystallographic growth direction of primary grains, grain and twin boundary length per unit area and etch-pit and subgrain boundary densities on a (111)-type plane. Measurements of these features were performed using the Laue X-ray backreflection technique and quantitative optical microscopy. No measurable difference in the microstructural features occurred as a result of using the 4.6 kG transverse magnetic field. The lack of any effect is attributed to either an insufficient magnetic field intensity or the possibility that the effect of a 4.6 kG transverse magnetic field on the fluid flow may not play a significant role in the mechanisms generating the microstructural features analyzed by the characterization techniques used in this study. Subgrain boundary densities were found to vary along the length of each boule and this variation was attributed to post-growth annealing. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP PRICE, MW (reprint author), UNIV ALABAMA,DEPT MAT SCI & ENGN,BIRMINGHAM,AL 35294, USA. NR 23 TC 7 Z9 7 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 MAR PY 1994 VL 137 IS 1-2 BP 201 EP 207 DI 10.1016/0022-0248(94)91272-6 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA NC995 UT WOS:A1994NC99500036 ER PT J AU BORSHCHEVSKY, A FLEURIAL, JP AF BORSHCHEVSKY, A FLEURIAL, JP TI RU2GE3 - CRYSTAL-GROWTH AND SOME PROPERTIES SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 9th American Conference on Crystal Growth (ACCG-9) CY AUG 01-06, 1993 CL BALTIMORE, MD SP AMER ASSOC CRYSTAL GROWTH, USAF OFF SPONSORED REG, NASA, NATL SCI FDN, AESAR ALFA JOHNSON MATTHEY, LITTON SYST, AIRTRON DIV, APPL TECHNOL INC, CERES CORP, CLEVELAND CRYSTALS, CRYSTAL ASSOC INC, CRYSTAL TECHNOL INC, CRYSTALLOD INC, DELTRONIC CRYSTAL IND, ENGELHARD CORP, JOHNSON MATTHEY ELECTR, JOHNSON MATTHEY INC, LASER DIODE INC, LIGHTNING OPT, MR SEMICON INC, SAINT GOBAIN NORTON, SENSORS UNLIMITED INC, STRUERS LOGITECH, SUMITOMO ELECT CORP, VIRGO OPT AB Large samples of Ru2Ge3 were grown from Ge-rich off-stoichiometric melts at a temperature close to 1460-degrees-C by a vertical gradient freeze method in graphite and glassy carbon crucibles. Diffusionless transition from a high temperature tetragonal structure to a low temperature orthorhombic structure causes twinning and crack formation. The thermal expansion coefficients of both low and high temperature phases were measured. Some electrical transport properties in the 25-1000-degrees-C temperature range in different crystallographic directions are also described for this high temperature semiconductor. Substantial anisotropy is observed. RP BORSHCHEVSKY, A (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 5 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAR PY 1994 VL 137 IS 1-2 BP 283 EP 288 DI 10.1016/0022-0248(94)91286-6 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA NC995 UT WOS:A1994NC99500050 ER PT J AU KELLEHER, SD HULTIN, HO WILHELM, KA AF KELLEHER, SD HULTIN, HO WILHELM, KA TI STABILITY OF MACKEREL SURIMI PREPARED UNDER LIPID-STABILIZING PROCESSING CONDITIONS SO JOURNAL OF FOOD SCIENCE LA English DT Article DE MACKEREL; SURIMI; FISH; LIPID OXIDATION; ANTIOXIDANTS ID SODIUM TRIPOLYPHOSPHATE; OXIDATION; SYSTEMS AB Surimi from mackerel whole and light muscle was prepared under conditions designed to minimize oxidation and development of rancidity. The lipid-stabilizing procedure included early addition of both lipid- and water-soluble antioxidants, avoidance of added sodium chloride, and exclusion of oxygen. Surimi prepared from light muscle was stable to rancid odor development in both the raw and cooked form; gel strength was reasonably stable during frozen storage, although the color was somewhat dark. Surimi prepared from mackerel whole muscle was darker, its odor quality lower and less consistent, and its gel strength lessened more rapidly during frozen storage than surimi prepared from light muscle. C1 UNIV MASSACHUSETTS,AGR EXPT STN,DEPT FOOD SCI,AMHERST,MA 01003. NOAA,NATL MARINE FISHERIES SERV,NE CTR LAB,GLOUCESTER,MA 01930. RP KELLEHER, SD (reprint author), UNIV MASSACHUSETTS,MARINE STN,POB 7128 LANESVILLE STN,GLOUCESTER,MA 01930, USA. NR 23 TC 19 Z9 24 U1 0 U2 2 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA SUITE 300 221 N LASALLE ST, CHICAGO, IL 60601-1291 SN 0022-1147 J9 J FOOD SCI JI J. Food Sci. PD MAR-APR PY 1994 VL 59 IS 2 BP 269 EP 271 DI 10.1111/j.1365-2621.1994.tb06945.x PG 3 WC Food Science & Technology SC Food Science & Technology GA NJ330 UT WOS:A1994NJ33000008 ER PT J AU LIAO, B BENBROOK, JR BERING, EA BYRNE, GJ THEALL, JR LANZEROTTI, LJ MACLENNAN, CG AF LIAO, B BENBROOK, JR BERING, EA BYRNE, GJ THEALL, JR LANZEROTTI, LJ MACLENNAN, CG TI BALLOON OBSERVATIONS OF NIGHTSIDE PC 5 QUASI-ELECTROSTATIC WAVES ABOVE THE SOUTH-POLE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOSPHERIC ELECTRIC FIELD; ATMOSPHERIC GRAVITY-WAVES; EQUATORIAL F-REGION; AURORAL E-REGION; IONOSPHERIC PLASMA; VELOCITY SHEARS; IRREGULARITIES; DENSITY; SPECTRA; THUNDERSTORM AB We report here a unique Pc 5 band quasi-electrostatic wave event (approximately 300-s period) observed near local geomagnetic midnight at an invariant latitude of 75-degrees. The electric field signal was obtained from one of the eight high-latitude balloon payloads launched above the south geographic pole during the South Pole Balloon Campaign in the 1985-86 austral summer. The balloon payloads were instrumented with double-probe electric field detectors and bremsstrahlung X ray detectors. The electric field data from one flight of particular interest have been compared with ground-based magnetometer and micropulsation data in an attempt to understand the nature of the wave event. The Pc 5 waves were linearly polarized in the electric field, the electric field components had amplitudes of 20 to 30 mV/m, and the event persisted for an interval of more than 3 hours from 0000 to 0330 UT (2030 to 2400 MLT) on December 22, 1985. The magnetic activity was quiet during this time period. Detailed power spectra are presented in the paper. No evidence was found suggesting that the event was produced by an artifact. The event was not associated with atmospheric neutral waves, weather processes, or upward propagating gravity waves. The event was produced in the ionosphere by a process other than the convection of irregularities. We suggest that ULF magnetosonic waves originating at the magnetopause produced the signals that were observed. C1 UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. MCDONNELL DOUGLAS,HOUSTON,TX 77059. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP LIAO, B (reprint author), FMC CORP,BOX 8,PRINCETON,NJ 08543, USA. NR 61 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1994 VL 99 IS A3 BP 3879 EP 3891 DI 10.1029/93JA02753 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ639 UT WOS:A1994MZ63900006 ER PT J AU ANDERSON, PC HANSON, WB COLEY, WR HOEGY, WR AF ANDERSON, PC HANSON, WB COLEY, WR HOEGY, WR TI SPACECRAFT POTENTIAL EFFECTS ON THE DYNAMICS EXPLORER 2 SATELLITE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SURFACES; MODEL AB The relationship between the plasma environment and spacecraft potential is examined for the Dynamics Explorer 2 (DE 2) spacecraft in an attempt to improve the accuracy of ion drift measurements by the retarding potential analyzer (RPA). Because of the DE 2 orbit characteristics (apogee near 1000 km and perigee near 300 km) and the configuration of conducting surfaces on the spacecraft, thermal electrons and ions constituted the only significant contributions to the charging currents to the spacecraft surface for the majority of geophysical conditions encountered. The geomagnetic field had considerable effect on the spacecraft potential due to magnetic field confinement of the electrons as well as to the V x B electric field resulting from the movement of the spacecraft across magnetic field lines. Using a database of inferred spacecraft potentials from the RPA, measured electron temperatures from the Langmuir probe (LANG), and calculated V x B electric fields, we derive an algorithm for determining the spacecraft potential (at the location of the RPA on the spacecraft) for any point of the DE 2 orbit. Knowledge of the spacecraft potential subsequently allows us to retrieve relatively accurate ion drifts from the RPA data. C1 UNIV TEXAS,CTR SPACE SCI,RICHARDSON,TX 75083. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHER LAB,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP ANDERSON, PC (reprint author), AEROSP CORP,CTR SPACE & ENVIRONM TECHNOL,MAIL STN M2-255,POB 92957,LOS ANGELES,CA 90009, USA. OI Coley, William Robin/0000-0003-2047-0002 NR 22 TC 18 Z9 18 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1994 VL 99 IS A3 BP 3985 EP 3997 DI 10.1029/93JA02104 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ639 UT WOS:A1994MZ63900015 ER PT J AU LIU, C PEREZ, JD MOORE, TE CHAPPELL, CR SLAVIN, JA AF LIU, C PEREZ, JD MOORE, TE CHAPPELL, CR SLAVIN, JA TI FINE-STRUCTURE OF LOW-ENERGY H+ IN THE NIGHTSIDE AURORAL REGION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TRANSVERSE ION-ACCELERATION; RETURN CURRENT REGION; FIELD LINES; PLASMA; DISTRIBUTIONS; CONICS; O+; ENERGIZATION; IONOSPHERE; ALTITUDE AB Low-energy H+ data with 6-s resolution from the retarding ion mass spectrometer instrument on DE 1 have been analyzed to reveal the fine structure at middle altitudes of the nightside auroral region. A new method for deconvolving the energy-integrated count rate in the spin plane of the satellite has been used to derive the two-dimensional phase space density. A detailed analysis reveals an alternating conic-beam-conic pattern with the observed conics correlated with large earthward currents in the auroral region. The strong downward current (>1 muA/m2(equivalent value at ionosphere)) provides a free energy source for the perpendicular ion heating, that generates the ion conics with energies from several eV to tens of eV. The bowl shape distribution of the low-energy H+ is caused by the extended perpendicular heating. The strong correlation between conics and large downward currents suggests that the current-driven electrostatic ion cyclotron wave is an appropriate candidate for the transverse heating mechanism. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP LIU, C (reprint author), AUBURN UNIV,DEPT PHYS,AUBURN,AL 36849, USA. RI Moore, Thomas/D-4675-2012; Slavin, James/H-3170-2012 OI Moore, Thomas/0000-0002-3150-1137; Slavin, James/0000-0002-9206-724X NR 34 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1994 VL 99 IS A3 BP 4131 EP 4141 DI 10.1029/93JA01989 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ639 UT WOS:A1994MZ63900027 ER PT J AU BURLAGA, LF AF BURLAGA, LF TI SHOCKS IN THE OUTER HELIOSPHERE - VOYAGER 2 OBSERVATIONS FROM 18.9 AU TO 30.2 AU (1986-1989) SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MULTIPLE SPACECRAFT OBSERVATIONS; SOLAR-WIND STRUCTURES; INTERPLANETARY SHOCKS; EVOLUTION AB A search for shocks observed by Voyager 2 from 1986.0 to day 233, 1989, in the region between 18.9 AU and 30.2 AU revealed only five candidate fast forward shocks and no reverse shocks. No shock was observed during 1987 (near solar minimum). Only one candidate shock was observed during 1986, when the heliospheric current sheet (HCS) was still close to the equator. This, the weakest of the shocks, was associated with a weak corotating merged interaction region (CMIR). Only two shocks were observed during 1988, when solar activity and the inclination of the HCS were increasing. One of these shocks was associated with a CMIR, the other with a local merged interaction region (MIR) (a transient MIR localized in space). The shocks observed between 18.9 AU and 28.2 AU from 1986 through 1988 were relatively weak, the estimated magnetoacoustic Mach number being less-than-or-equal-to 1.5 for each of the three shocks. Since the shocks observed between 20 AU and 29 AU during the 3-year period centered around solar minimum were weak and few in number, shocks were not important in determining the structure, dynamics, and thermodynamics of the equatorial solar wind. The strongest shock in this study was observed during 1989 at the front of a global merged interaction region (GMIR) (a MIR that extends around the Sun and is presumably formed by the coalescence of several transient ejecta and other interaction regions). A weak shock was also observed inside this GMIR. RP BURLAGA, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 18 TC 25 Z9 25 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1994 VL 99 IS A3 BP 4161 EP 4171 DI 10.1029/93JA03242 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ639 UT WOS:A1994MZ63900029 ER PT J AU BAVASSANO, B IUCCI, N LEPPING, RP SIGNORINI, C SMITH, EJ VILLORESI, G AF BAVASSANO, B IUCCI, N LEPPING, RP SIGNORINI, C SMITH, EJ VILLORESI, G TI GALACTIC COSMIC-RAY MODULATION AND INTERPLANETARY MEDIUM PERTURBATIONS DUE TO A LONG-LIVING ACTIVE-REGION DURING OCTOBER 1989 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC CLOUDS; FORBUSH DECREASES AB During October 1989, three very energetic flares were ejected by the same active region at longitudes 9-degrees-E, 32-degrees-W, and 57-degrees-W, respectively. The shape of the galactic cosmic ray variations suggests the presence of large magnetic cloud structures (Nagashima et al, 1990) following the shock-associated perturbations. In spite of long data gaps the interplanetary observations at IMP 8 (near the Earth) and ICE (approximately 1 AU, approximately 65-degrees W) confirm this possibility for the event related to the 9-degrees-E flare; the principal axes analysis shows that the interplanetary magnetic field variations at both spacecaft locations are mainly confined on a meridian plane. This result suggests that the western longitudinal extension of this cloud is indeed very large (greater-than-or-equal-to 75-degrees). The nonnegligible depression in the cosmic ray intensity observed inside the possible cloud related to the 57-degrees-W flare indicates that also the eastern extension could be very wide. The analysis of neutron monitor data shows clearly the cosmic ray trapping effect of magnetic clouds; this mechanism seems to be responsible for the enhanced diurnal effect often observed during the recovery phase of Forbush decreases. We give an interpretation for the anisotropic cosmic ray peak occurring in the third event, and, related to that, we suggest that the Forbush decrease modulated region at the Earth's orbit could be somewhat wider than the magnetic cloud, as already anticipated by Nagashima et al. (1990). By this analysis, based mainly on cosmic ray data, we show that it is possible to do reasonable inferences on the large-scale structure of flare-related interplanetary perturbations when interplanetary medium data are not completely present. C1 UNIV ROMA LA SAPIENZA,DIPARTIMENTO FIS,ROME,ITALY. JET PROP LAB,PASADENA,CA 91109. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BAVASSANO, B (reprint author), CNR,IST FIS SPAZIO INTERPLANETARIO,FRASCATI,ITALY. NR 18 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1994 VL 99 IS A3 BP 4227 EP 4234 DI 10.1029/93JA03135 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ639 UT WOS:A1994MZ63900035 ER PT J AU LIU, K SKELTON, RE SHARKEY, JP AF LIU, K SKELTON, RE SHARKEY, JP TI MODELING HUBBLE-SPACE-TELESCOPE FLIGHT DATA BY Q-MARKOV COVER IDENTIFICATION SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SYSTEMS AB This paper presents a state-space model for the Hubble space telescope under the influence of unknown disturbances in orbit. This model was obtained from night data by applying the Q-Markov Covariance Equivalent Realization (Q-Markov Cover) identification algorithm. This state-space model guarantees the match of the first Q-Markov parameters and covariance parameters of the Hubble system. The flight data were partitioned into high- and low-frequency components for more efficient Q-Markov Cover modeling to reduce some computational difficulties of the Q-Markov Cover algorithm. This identification revealed more than 20 lightly damped modes within the bandwidth of the attitude control system. Comparisons with the analytical (TREETOPS) model are also included. C1 PURDUE UNIV,SPACE SYST CONTROL LAB,W LAFAYETTE,IN 47907. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP LIU, K (reprint author), PURDUE UNIV,SCH AERONAUT & ASTRONAUT,W LAFAYETTE,IN 47907, USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1994 VL 17 IS 2 BP 250 EP 256 DI 10.2514/3.21190 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA NC789 UT WOS:A1994NC78900004 ER PT J AU BALACHANDRAN, B NAYFEH, AH SMITH, SW PAPPA, RS AF BALACHANDRAN, B NAYFEH, AH SMITH, SW PAPPA, RS TI IDENTIFICATION OF NONLINEAR-INTERACTIONS IN STRUCTURES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID DYNAMIC-SYSTEMS AB Recent experiences in phenomenological identification of nonlinear interactions in structures are presented. Free oscillations of quadratically and cubically coupled pairs of oscillators are analytically studied to illustrate nonlinear interactions between structural modes involved in two-to-one and one-to-one frequency relationships. In light of this analytical study, results obtained from application of the Eigensystem Realization Algorithm (ERA) toward identification of a beam-mass structure with a two-to-one frequency relationship and quadratic coupling are presented and discussed. The internal resonance in the structure causes the identified damping coefficients to be oscillatory and to assume negative values. The present effort should be of relevance to the identification of structural systems in which factors, such as symmetry, modal density, frequency relationships, and flexibility contribute to the likelihood that nonlinear interactions may occur. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061. UNIV KENTUCKY,DEPT ENGN MECH,LEXINGTON,KY 40506. NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,HAMPTON,VA 23665. NR 17 TC 3 Z9 3 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1994 VL 17 IS 2 BP 257 EP 262 DI 10.2514/3.21191 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA NC789 UT WOS:A1994NC78900005 ER PT J AU QUINN, RD CHEN, JL LAWRENCE, C AF QUINN, RD CHEN, JL LAWRENCE, C TI BASE REACTION CONTROL FOR SPACE-BASED ROBOTS OPERATING IN MICROGRAVITY ENVIRONMENT SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID MANIPULATORS AB Specialized robots are needed for space stations to conduct experiments and operations without disturbing the microgravity environment through base reactions and/or base motions. Approaches for controlling the robot base include 1) manipulators with redundant degrees of freedom, 2) actuators at the robot base, and 3) a redundant (balancing) arm. An approach making use of manipulator kinematic redundance is explored in detail and both locally and globally optimal trajectory management schemes are discussed. The inverse kinematic problem is solved at discrete time steps simultaneously with the minimization of the robot's base reactions. Numerical examples are presented including various robotic configurations and degrees of manipulator kinematic redundance. A significant reduction in base reactions is observed in each case. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP QUINN, RD (reprint author), CASE WESTERN RESERVE UNIV,DEPT MECH & AEROSP ENGN,CLEVELAND,OH 44106, USA. NR 13 TC 8 Z9 8 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1994 VL 17 IS 2 BP 263 EP 270 DI 10.2514/3.21192 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA NC789 UT WOS:A1994NC78900006 ER PT J AU MARKLEY, FL AF MARKLEY, FL TI NEW QUATERNION ATTITUDE ESTIMATION METHOD SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note ID VECTOR OBSERVATIONS; DECOMPOSITION RP MARKLEY, FL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GUIDANCE & CONTROL BRANCH,CODE 712,GREENBELT,MD 20771, USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1994 VL 17 IS 2 BP 407 EP 409 DI 10.2514/3.21212 PG 3 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA NC789 UT WOS:A1994NC78900026 ER PT J AU BREININGER, DR SCHMALZER, PA HINKLE, CR AF BREININGER, DR SCHMALZER, PA HINKLE, CR TI GOPHER TORTOISE (GOPHERUS-POLYPHEMUS) DENSITIES IN COASTAL SCRUB AND SLASH PINE FLATWOODS IN FLORIDA SO JOURNAL OF HERPETOLOGY LA English DT Article ID NORTHERN FLORIDA; MANAGEMENT; HABITAT AB Densities of gopher tortoises were compared with habitat characteristics in scrub and in flatwood habitats on the Kennedy Space Center, Florida. Tortoises were distributed widely among habitat types and did not have higher densities in well-drained (oak-palmetto) than in poorly-drained (saw palmetto) habitats. Fall densities of tortoises ranged from a mean of 2.7 individuals/ha in disturbed habitat to 0.0 individuals/ha in saw palmetto habitat. Spring densities of tortoises ranged from a mean of 2.5 individuals/ha in saw palmetto habitat to 0.7 individuals/ha in oak-palmetto habitat. Densities of tortoises were correlated positively with the percent herbaceous cover, an indicator of food resources. Plots were divided into three burn classes; these were areas burned within three years, burned four to seven years, and unburned for more than seven years prior to the study. Relationships between densities of tortoises and time-since-fire classes were inconsistent. RP BREININGER, DR (reprint author), NASA,BIOMED OPERAT & RES OFF,BIONET CORP,MAIL CODE BIO-2,KENNEDY SPACE CTR,FL 32899, USA. OI Schmalzer, Paul/0000-0003-2214-0074 NR 32 TC 21 Z9 22 U1 5 U2 21 PU SOC STUD AMPHIBIANS REPTILES PI OXFORD PA DEPT OF ZOOLOGY MIAMI UNIV, OXFORD, OH 45056 SN 0022-1511 J9 J HERPETOL JI J. Herpetol. PD MAR PY 1994 VL 28 IS 1 BP 60 EP 65 DI 10.2307/1564681 PG 6 WC Zoology SC Zoology GA ND803 UT WOS:A1994ND80300010 ER PT J AU WANG, FY MITTMANN, M SARIDIS, GN AF WANG, FY MITTMANN, M SARIDIS, GN TI COORDINATION SPECIFICATION FOR CIRSSE ROBOTIC PLATFORM SYSTEM USING PETRI-NET TRANSDUCERS SO JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS LA English DT Article DE PETRI NET TRANSDUCER; COORDINATION STRUCTURE; COMMAND LANGUAGE; COMMUNICATION; INTELLIGENT MACHINES ID INTELLIGENT MACHINES AB A formal model based on Petri net transducers has been developed to specify the coordination and communication among the various task units in the CIRSSE platform system for robotic construction in space stations. The specification guarantees a mechanism of coherent control and communication for the effective cooperation among the different task units, and outlines the major steps toward the integration of the robotic platform system. The model is based on a coordination structure consisting of one dispatcher and three coordinators representing, respectively, the motion, vision, and gripper units of the platform system. The coordination structure insures some desired process properties for the system, such as boundedness, liveness, and reversibility, and easier translation from the formal specifications to the program codes based on Petri net transducer models. The model also assists with the system development in many ways, including (i) reducing the number of errors introduced while converting specifications to codes; (ii) assisting the developers in program implementation and verification (iii) allowing quicker adaptation to changed specifications; and (iv) allowing easier testing of the results for specification modifications. Therefore, it provides a useful tool for the design, simulation, performance evaluation, and implementation verification of the CIRSSE robotic platform system. C1 RENSSELAER POLYTECH INST,NASA,CTR INTELLIGENT ROBOT SYST SPACE EXPLORAT,TROY,NY 12180. RP WANG, FY (reprint author), UNIV ARIZONA,DEPT SYST & IND ENGN,TUCSON,AZ 85721, USA. NR 19 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0921-0296 J9 J INTELL ROBOT SYST JI J. Intell. Robot. Syst. PD MAR PY 1994 VL 9 IS 3 BP 209 EP 233 DI 10.1007/BF01276499 PG 25 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA PB980 UT WOS:A1994PB98000002 ER PT J AU ABEL, PB KORENYIBOTH, AL HONECY, FS PEPPER, SV AF ABEL, PB KORENYIBOTH, AL HONECY, FS PEPPER, SV TI STUDY OF COPPER ON GRAPHITE WITH TITANIUM OR CHROMIUM BOND LAYER SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ELECTRON-MICROSCOPY; CARBON; ALLOYS; FIBER; RESOLUTION; COMPOSITES; CU AB Improvement of copper to graphite adhesion by thin interfacial films of titanium and chromium was investigated. Graphite fibers and highly oriented pyrolytic graphite flats were sputter-coated first with 10 nm of titanium or chromium and then with 50 nm of copper. After annealing to 970-degrees-C in argon/5%-hydrogen at atmospheric pressure for 5 min, copper without an interfacial bond layer agglomerated into nearly spherical particles, copper with the chromium bond layer agglomerated into particles with a contact angle less than 90-degrees, indicating improvement in adhesion, and copper with the titanium bond layer exhibited a continuous metal film. In the latter case, most of the interfacial titanium was observed to have migrated into the copper and to the free surface, where the titanium reacted with contaminants in the annealing ambient. RP ABEL, PB (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 29 Z9 29 U1 0 U2 4 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAR PY 1994 VL 9 IS 3 BP 617 EP 624 DI 10.1557/JMR.1994.0617 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA MZ039 UT WOS:A1994MZ03900012 ER PT J AU CHEN, JS KOLAWA, E NICOLET, MA RUIZ, RP BAUD, L JAUSSAUD, C MADAR, R AF CHEN, JS KOLAWA, E NICOLET, MA RUIZ, RP BAUD, L JAUSSAUD, C MADAR, R TI SOLID-STATE REACTION OF PT THIN-FILM WITH SINGLE-CRYSTAL (001) BETA-SIC SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-CARBIDE; GROWTH-KINETICS; NUCLEATION; PHASE; INTERFACE; SILICIDES AB Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) beta-SiC substrate at temperatures from 300-degrees-C to 1000-degrees-C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500-degrees-C. The product phase identified by x-ray diffraction is Pt3Si. At 600-900-degrees-C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000-degrees-C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500-900-degrees-C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC-Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt // {001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400-degrees-C. At 450-degrees-C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500-degrees-C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si-Pt is discussed. C1 JET PROP LAB,PASADENA,CA 91109. CENG,DMEL,CEA TECHNOL AVANCEES,LETI,F-38041 GRENOBLE,FRANCE. ENSPG,LMGP,F-38402 ST MARTIN DHERES,FRANCE. RP CHEN, JS (reprint author), CALTECH,PASADENA,CA 91125, USA. RI Chen, Jen-Sue/A-3298-2015 NR 27 TC 18 Z9 18 U1 0 U2 9 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAR PY 1994 VL 9 IS 3 BP 648 EP 657 DI 10.1557/JMR.1994.0648 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA MZ039 UT WOS:A1994MZ03900017 ER PT J AU UNGAR, AA AF UNGAR, AA TI THE ABSTRACT COMPLEX LORENTZ TRANSFORMATION GROUP WITH REAL METRIC .1. SPECIAL RELATIVITY FORMALISM TO DEAL WITH THE HOLOMORPHIC AUTOMORPHISM GROUP OF THE UNIT BALL IN ANY COMPLEX HILBERT-SPACE SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID THOMAS AB Viewing the unit ball in a complex Hilbert space as a set of relativistically admissible complex velocities, the holomorphic automorphisms of the ball emerge as ''complex relativistic velocity additions'' and ''complex rotations'' (that is, unitary transformations). Hence, newly discovered properties of the abstract real Lorentz group [A. A. Ungar, Am. J. Phys. 59, 824 (1991); A. A. Ungar, Am. J. Phys. 60, 815 (1992)], which turn out to provide powerful tools for the study of the holomorphic automorphisms of the unit ball in any complex Hilbert space, are of interest in the literature [W. Rudin, Function Theory in the Unit Ball of C(n) (Springer-Verlag, New York, 1980)]. A particularly useful and important tool turns out to be provided by Thomas gyration, which is an abstraction of the well-known Thomas precession of special relativity theory, and which gives rise to a gyrogroup structure underlying the ball. Results of this article set the stage for the study, in a subsequent article, of complex Lorentz transformation groups, U(1,n), in a way analogous to the study of Galilean groups. The dimension n is finite or infinite, and a real parameter c is involved in such a way that in the limit of large c, c --> infinity, the Lorentz groups that we study reduce to their Galilean counterparts. RP UNGAR, AA (reprint author), NOAA,MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 37 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD MAR PY 1994 VL 35 IS 3 BP 1408 EP 1426 DI 10.1063/1.530597 PG 19 WC Physics, Mathematical SC Physics GA MZ254 UT WOS:A1994MZ25400025 ER PT J AU SMITH, MAH RINSLAND, CP DEVI, VM PROCHASKA, ES AF SMITH, MAH RINSLAND, CP DEVI, VM PROCHASKA, ES TI MEASUREMENTS OF PRESSURE BROADENING AND SHIFTS OF O(3) LINES IN THE 3-MU-M REGION SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID TEMPERATURE-DEPENDENCE; OZONE LINES; ROVIBRATIONAL TRANSITIONS; MU-M; AIR; NITROGEN; COEFFICIENTS; INTENSITIES; OXYGEN; O-3 AB We have recorded high-resolution Fourier transform absorption spectra of ozone broadened by dry air, by N2, or by O2 at room temperature. From these spectra we have determined pressure-broadening and line-shift coefficients for over 270 lines in the nu1 + nu2 + nu3 and 3nu3 bands. The Lorentz broadening coefficients obtained in these bands are similar to those determined from measurements in the nu1, nu3, and nu1 + nu3 bands. However, there is some evidence for a small vibrational dependence of the broadening coefficients. As expected, the pressure-induced lineshifts determined in the 3-mum hands are significantly larger than those observed in the 4.8- and 9-mum regions. (C) 1994 Academic Press, Inc. C1 COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187. WESTERN CAROLINA UNIV,DEPT MATH & COMP SCI,CULLOWHEE,NC 28723. RP SMITH, MAH (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 24 TC 13 Z9 14 U1 1 U2 2 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 MAR PY 1994 VL 164 IS 1 BP 239 EP 259 DI 10.1006/jmsp.1994.1070 PG 21 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA MZ377 UT WOS:A1994MZ37700018 ER PT J AU SINGH, DJ TREXLER, CA YOUNG, JAH AF SINGH, DJ TREXLER, CA YOUNG, JAH TI 3-DIMENSIONAL SIMULATION OF A TRANSLATING STRUT INLET SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A three-dimensional Navier-Stokes code is used to numerically simulate the flow through a variable-geometry, reverse-sweep side wall compression scramjet inlet. The strut of the inlet is allowed to translate back and forth, it is moved forward to help start the inlet by spilling some of the air at low speed, and is moved backward once the inlet has started to provide a high contraction ratio, and therefore, high compression at high speed. The focus of this study is on detailed examination of the flow characteristics in this complex three-dimensional geometry. Flowfield features such as the top wall separation and cowl pressure, as well as the effects of reverse sweep, compression, and flow distortion (nonuniformity) are investigated. The effects of vehicle undersurface boundary-layer ingestion on the flowfield are also investigated. Comparisons with experimental results are made to provide for the assessment of the present analysis. C1 NASA,LANGLEY RES CTR,DIV FLUID MECH,HYPERSON PROPULS BRANCH,HAMPTON,VA 23631. RP SINGH, DJ (reprint author), ANAL SERV & MAT INC,107 RES DR,HAMPTON,VA 23666, USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1994 VL 10 IS 2 BP 191 EP 197 DI 10.2514/3.23729 PG 7 WC Engineering, Aerospace SC Engineering GA NA094 UT WOS:A1994NA09400008 ER PT J AU BARANKIEWICZ, WS PERUSEK, GP IBRAHIM, MB AF BARANKIEWICZ, WS PERUSEK, GP IBRAHIM, MB TI APPROXIMATE SIMILARITY PRINCIPLE FOR A FULL-SCALE STOVL EJECTOR SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Full-scale ejector experiments are expensive and difficult to implement at engine exhaust temperatures. For this reason the utility of using similarity principles, in particular the Munk and Prim principle for isentropic now, was explored. Static performance test data for a full-scale thrust augmenting ejector were analyzed for primary flow temperatures up to 1560-degrees-R. At different primary temperatures, exit pressure contours were compared for similarity. A nondimensional flow parameter is then used to eliminate primary nozzle temperature dependence and verify similarity between the hot and cold flow experiments. Under the assumption that an appropriate similarity principle can be established, properly chosen performance parameters were found to be similar for both hot flow and cold flow model tests. C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44115. RP BARANKIEWICZ, WS (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 5 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1994 VL 10 IS 2 BP 198 EP 203 DI 10.2514/3.23730 PG 6 WC Engineering, Aerospace SC Engineering GA NA094 UT WOS:A1994NA09400009 ER PT J AU RAY, A DAI, XW WU, MK CARPINO, M LORENZO, CF AF RAY, A DAI, XW WU, MK CARPINO, M LORENZO, CF TI DAMAGE-MITIGATING CONTROL OF A REUSABLE ROCKET ENGINE SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID FATIGUE AB This article presents a control concept for damage prediction and damage mitigation in reusable rocket engines for enhancement of structural durability. The key idea here is to achieve high performance without overstraining the mechanical structures so that 1) the functional lives of critical components are increased, resulting in enhanced safely, operational reliability, and availability; and 2) the plant (i.e., the rocket engine) can be inexpensively maintained, and safely and efficiently driven under different operating conditions. To this effect, dynamics of fatigue damage have been modeled in the continuous-time setting instead of the conventional cycle-based approach, and an optimal control policy is formulated by constraining the accumulated damage and its time derivative. Efficacy of the proposed damage mitigation concept is evaluated for life extension of the turbine blades of a bipropellant rocket engine via simulation experiments. The simulation results demonstrate the potential of increasing the structural durability of reusable rocket engines with no significant loss of performance. C1 NASA,LEWIS RES CTR,SYST DYNAM BRANCH,CLEVELAND,OH 44135. RP RAY, A (reprint author), PENN STATE UNIV,DEPT MECH ENGN,UNIV PK,PA 16802, USA. NR 23 TC 10 Z9 10 U1 1 U2 1 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 MAR-APR PY 1994 VL 10 IS 2 BP 225 EP 234 DI 10.2514/3.23733 PG 10 WC Engineering, Aerospace SC Engineering GA NA094 UT WOS:A1994NA09400012 ER PT J AU DEVI, VM BENNER, DC SMITH, MAH RINSLAND, CP AF DEVI, VM BENNER, DC SMITH, MAH RINSLAND, CP TI TEMPERATURE-DEPENDENCE OF LORENTZ AIR-BROADENING AND PRESSURE-SHIFT COEFFICIENTS OF (CH4)-C-12 LINES IN THE 2.3-MU-M SPECTRAL REGION SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID 720-NM WAVELENGTH REGION; WATER-VAPOR; NU-3 BAND; METHANE; LINEWIDTHS; NITROGEN AB High-resolution (0.01 cm-1) absorption spectra of lean mixtures of CH4 in dry air were recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak at various temperatures between 24 and -61-degrees-C. The spectra have been analysed to determine the values at room temperature of pressure-broadened widths and pressure-induced shifts of more than 740 transitions. The temperature dependence of air-broadened widths and pressure-induced shifts was deduced for approx. 370 transitions in the nu1 + nu4, nu3 + nu4, and nu2 + nu3 bands of (CH4)-C-12 located between 4118 and 4615 cm-1. These results were obtained by analysing a total of 29 spectra simultaneously using a multi-spectral non-linear least-squares fitting technique. This new technique allowed the determination of correlated spectral line parameters (e.g. intensity and broadening coefficient) better than the procedure of averaging values obtained by fitting the spectra individually. This method also provided a direct determination of the uncertainties in the retrieved parameters due to random errors. For each band analysed in this study the dependence of the various spectral line parameters upon the tetrahedral symmetry species and the rotational quantum numbers of the transitions is also presented. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP DEVI, VM (reprint author), COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187, USA. NR 15 TC 26 Z9 26 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 1994 VL 51 IS 3 BP 439 EP 465 DI 10.1016/0022-4073(94)90146-5 PG 27 WC Optics; Spectroscopy SC Optics; Spectroscopy GA NH222 UT WOS:A1994NH22200001 ER PT J AU MISHCHENKO, MI LACIS, AA TRAVIS, LD AF MISHCHENKO, MI LACIS, AA TRAVIS, LD TI ERRORS INDUCED BY THE NEGLECT OF POLARIZATION IN RADIANCE CALCULATIONS FOR RAYLEIGH-SCATTERING ATMOSPHERES SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID INVARIANT IMBEDDING METHOD; PLANETARY-ATMOSPHERES; MULTIPLE-SCATTERING; MOLECULAR-SCATTERING; WEAK LOCALIZATION; LIGHT; BACKSCATTERING; NEPTUNE; URANUS AB Although neglecting polarization and replacing the rigorous vector radiative transfer equation by its approximate scalar counterpart has no physical background, it is a widely used simplification when the incident light is unpolarized and only the intensity of the reflected light is to be computed. In this paper we employ accurate vector and scalar multiple-scattering calculations to perform a systematic study of the errors induced by the neglect of polarization in radiance calculations for a homogeneous, plane-parallel Rayleigh-scattering atmosphere (with and without depolarization) above a Lambertian surface. Specifically, we calculate percent errors in the reflected intensity for various directions of light incidence and reflection, optical thicknesses of the atmosphere, single-scattering albedos, depolarization factors, and surface albedos. The numerical data displayed can be used to decide whether or not the scalar approximation may be employed depending on the parameters of the problem. We show that the errors decrease with increasing depolarization factor and/or increasing surface albedo. For conservative or nearly conservative scatter-ing and small surface albedos, the errors are maximum at optical thicknesses of about 1. The calculated errors may be too large for some practical applications, and, therefore, rigorous vector calculations should be employed whenever possible. However, if approximate scalar calculations are used, we recommend to avoid geometries involving phase angles equal or close to 0-degrees and 90-degrees, where the errors are especially significant. We propose a theoretical explanation of the large vector/scalar differences in the case of Rayleigh scattering. According to this explanation, the differences are caused by the particular structure of the Rayleigh scattering matrix and come from lower-order (except first-order) light scattering paths involving right scattering angles and right-angle rotations of the scattering plane. RP MISHCHENKO, MI (reprint author), NASA,GODDARD INST SPACE STUDIES,HUGHES STX CORP,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Lacis, Andrew/D-4658-2012; Mishchenko, Michael/D-4426-2012 NR 37 TC 78 Z9 78 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 1994 VL 51 IS 3 BP 491 EP 510 DI 10.1016/0022-4073(94)90149-X PG 20 WC Optics; Spectroscopy SC Optics; Spectroscopy GA NH222 UT WOS:A1994NH22200004 ER PT J AU LONG, ER AF LONG, ER TI ENHANCEMENT OF ULTRASONIC IMAGES OF DEFECTS IN 3-D COMPOSITE SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article AB Image enhancement and analysis methods are applied to ultrasonic C-scans of stitched, resin transferred molded 3-D composites to make their quality for visual determination of the amount of porosity defect equal to that for 2-D composites conventionally fabricated from prepreg. The application of these methods is necessary because the 3-D reinforcing fiber architecture, along which the porosity tends to form during fabrication, is also imaged in the ultrasonic c-scans, thus severely limiting the visual determination of the amount of porosity present. Comparisons are made of the C-scan images of a stitched panel before and after the application of image enhancement and analysis methods to demonstrate the value of the methods. The importance of the number of shades of gray in the image for visual interpretation of defects and for the application of the enhancement methods is also discussed. RP LONG, ER (reprint author), NASA,LANGLEY RES CTR,DIV MAT,APPL MAT BRANCH,HAMPTON,VA 23681, USA. NR 9 TC 1 Z9 1 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. PD MAR PY 1994 VL 13 IS 3 BP 271 EP 285 DI 10.1177/073168449401300307 PG 15 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA MW671 UT WOS:A1994MW67100007 ER PT J AU ROBINSON, P LEE, W AGUERO, R GABRIEL, S AF ROBINSON, P LEE, W AGUERO, R GABRIEL, S TI ANOMALIES DUE TO SINGLE EVENT UPSETS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 28th Aerospace Sciences Meeting CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB This paper reviews the simple idea of single event phenomena presented in the Air Force Geophysics Laboratory spacecraft anomalies handbook, and outlines how they can be extended to compare seemingly conflicting ground-test results. RP ROBINSON, P (reprint author), JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. OI Gabriel, Stephen B./0000-0002-3226-8496 NR 16 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 166 EP 171 DI 10.2514/3.26418 PG 6 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200004 ER PT J AU LAURIENTE, M AF LAURIENTE, M TI ONLINE SPACECRAFT ENVIRONMENT INTERACTIONS INFORMATION-SYSTEM SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 28th Aerospace Sciences Meeting CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB EnviroNET is a computerized text type data base that provides rapid access to the latest information on a variety of space environments and spacecraft interactions of importance to understanding anomalies. Although originally intended as a design guide for Space Shuttle users, it has grown into a valuable resource of information on spacecraft charging and near-Earth charging environments. Included in the services is interactive modeling, some of which are also of interest for diagnosing anomalies. A more recent development is the on-line expert system for diagnosing anomalies. The expert system combines algorithms with expert heuristic knowledge, and uses confidence factors in variables and rules to calculate results with degrees of confidence associated with them. RP LAURIENTE, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ENVIRONET PROJECT,GREENBELT,MD 20771, USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 182 EP 185 DI 10.2514/3.26421 PG 4 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200007 ER PT J AU QUEEN, EM WARNER, MS MOERDER, DD AF QUEEN, EM WARNER, MS MOERDER, DD TI MONTE-CARLO SIMULATION OF LAUNCH SITE WINDS AT KENNEDY-SPACE-CENTER SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper develops an easily implemented model for simulating random horizontal wind profiles over the Kennedy Space Center (KSC) at Cape Canaveral, Florida. The model is intended for use in Monte Carlo launch vehicle simulations of the type employed in mission planning. In this type of simulation, the large number of profiles needed for statistical fidelity of such simulation experiments makes the use of actual wind measurements impractical. The model is based on measurements made at KSC and represents vertical correlations by a decaying exponential model that is parameterized via least-squares parameter fit to the sample data. The model is demonstrated by comparing two open-loop Monte Carlo simulations of an asymmetric, heavy-lift launch vehicle. In the first simulation, measured wind profiles are used, whereas in the second, the wind profiles are generated using the stochastic model. The simulations indicate that the use of either the measured or simulated wind field results in similar launch vehicle performance. Although the model documented here is based on winter data, it can easily be adapted to other seasons. C1 GEORGE WASHINGTON UNIV,HAMPTON,VA 23681. RP QUEEN, EM (reprint author), NASA,LANGLEY RES CTR,SPACECRAFT CONTROL BRANCH,HAMPTON,VA 23681, USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 249 EP 258 DI 10.2514/3.26430 PG 10 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200016 ER PT J AU GRIFFIN, OH HYER, MW COHEN, D SHUART, MJ YALAMANCHILI, SR PRASAD, CB AF GRIFFIN, OH HYER, MW COHEN, D SHUART, MJ YALAMANCHILI, SR PRASAD, CB TI ANALYSIS OF MULTIFASTENER COMPOSITE JOINTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID STRENGTH AB A new numerical procedure for determining load proportioning in multifastener mechanical joints in composite plates is presented. The joints are loaded in double lap fashion in tension with pins through the holes. The commercial finite element program ABAQUS is used to predict the load proportioning among fasteners using two independent plane stress finite element models, one representing the composite inner lap and one representing the two steel outer laps, interacting through rigid circular surfaces. The circular surfaces effectively represent rigid pins. Load proportioning is predicted for a number of geometries. Excellent correlation with experimental data is obtained. Experimental and computed surface strains are aw found to compare well. The assumption of a radial cosine distribution of contact stress between fastener and hole boundary, often used in these studies, is shown to be substantially in error for some holes. C1 HERCULES INC,BACCHUS WORKS,MAGNA,UT 84044. NASA,LANGLEY RES CTR,DIV STRUCT MECH,HAMPTON,VA 23681. GE CO,TRUCK ENGN,WARREN,MI 48091. ANALYT SERV & MAT INC,HAMPTON,VA 23666. RP GRIFFIN, OH (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061, USA. NR 13 TC 15 Z9 15 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 MAR-APR PY 1994 VL 31 IS 2 BP 278 EP 284 DI 10.2514/3.26434 PG 7 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200020 ER PT J AU RAMACHANDRAN, N DOWNEY, JP AF RAMACHANDRAN, N DOWNEY, JP TI 3-DIMENSIONAL NUMERICAL INVESTIGATION OF GRAVITATIONAL AND SOLUTAL EFFECTS IN A CYLINDRICAL CELL SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID CIRCULAR-CYLINDER; CONVECTION; FLUID; GASES AB Three-dimensional numerical computations of natural convection in a cylindrical ampoule (L/R = 4) are presented for a gallium doped germanium melt. ne ampoule is maintained at isothermal end conditions and the g vector is orientated at an angle gamma with the horizontal cylinder axis. Detailed velocity, temperature, and concentration field distributions are presented for different gravity levels and for a range of inclination angles (0 less-than-or-equal-to gamma less-than-or-equal-to 180 deg). For terrestrial conditions (1g0, where go is Earth gravity), complex, multicellular flow is found to occur for 0 less-than-or-equal-to gamma < 180 deg. The strong convection results in significant isotherm distortions and enhanced heat transfer. As the gravity level is reduced to 10(-3) g0, the overall convection strength decays but the three-dimensional, multicellular flow persists causing appreciable mass transfer. For a further reduction in the gravity level to 10(-5) g0, the system thermal characteristics approach purely diffusive conditions. Flow, thermal, and solutal distributions are presented in the principal, orthogonal, and cross-sectional planes; and the average system heat and mass transfer are calculated. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP RAMACHANDRAN, N (reprint author), UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812, USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 304 EP 311 DI 10.2514/3.26438 PG 8 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200024 ER PT J AU NOEVER, DA AF NOEVER, DA TI FOAM FRACTIONATION OF PARTICLES IN LOW GRAVITY SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Foam fractionation of heavy particles has been obtained aboard an aircraft that provides a low-gravity environment by flying parabolic trajectories. Results for large silica, glass, and steel pellets (>0.2 mm) show that, using minimally supporting froths, both mass transport and separation are possible. For single-pass batch separations in low gravity, concentration factors reached threefold (compared with a ninefold theoretical limit and no separation in unit gravity). The impact of reduced gravity is discussed for splitting large particle sizes from low surfactant fluids; possible interest includes bubbling premium biologicals (whole cells, proteins, and viruses, etc.) from native solutions without surfactant addition or membrane disruption. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,BIOPHYS BRANCH,ES-76,HUNTSVILLE,AL 35812, USA. NR 20 TC 5 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 319 EP 322 DI 10.2514/3.26440 PG 4 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200026 ER PT J AU BLAIR, JC RYAN, RS AF BLAIR, JC RYAN, RS TI ROLE OF CRITERIA IN DESIGN AND MANAGEMENT OF SPACE SYSTEMS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Requirements and standards are used in two ways that are highly interrelated. First, they serve as the framework for managing technical and project aspects of a spacecraft or space vehicle. Second, they provide formal control or direction (legal) to the development, verification, and operations of these systems. There exist in addition many good practices and lessons-learned guideline documents that can guide the design. These, however, are not contractually binding. The legal requirements usually consist of the basic performance requirements for the system and the design requirements that provide verifiable requirements such as structural safety factors, stability margins, process control, materials selection, etc. As the project develops, additional requirements are derived peculiar to the system under development. These are labeled derived requirements and are fundamental to program success. The assurance of low-cost, reliable space systems occurs when a proper balance exists between the formal and the informal and uses the proper development of derived requirements to anchor the informal. This paper will deal with this balance, the guidelines for the management approach, and the development of the criteria consistent with the basic philosophy developed. Total Quality Management (TQM) will be the guiding star used. RP BLAIR, JC (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT & DYNAM LAB,ED01,HUNTSVILLE,AL 35812, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 323 EP 329 DI 10.2514/3.26441 PG 7 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200027 ER PT J AU BAILEY, SG CHIARAMONTE, FP DAVIDIAN, KJ AF BAILEY, SG CHIARAMONTE, FP DAVIDIAN, KJ TI INTERNATIONAL SPACE UNIVERSITY VARIABLE GRAVITY RESEARCH FACILITY DESIGN SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A manned mission to Mars will require long travel times between Earth and Mars. However, exposure to long-duration zero gravity is known to be harmful to the human body. Some of the harmful effects am loss of heart and lung capacity, inability to stand upright, muscular weakness, and loss of bone calcium. A variable gravity research facility (VGRF) that will be placed in low Earth orbit (LEO) was designed by students of the International Space University 1989 Summer Session held in Strasbourg, France, to provide a testbed for conducting experiments in the life and physical sciences in preparation for a mission to Mars. This design exercise was unique because it addressed all aspects concerning a large space project. This report describes the VGRF design that was developed by international participants specializing in the following areas: the politics of international cooperation; engineering, architecture; in-space physiological, materials, and life science experimentation; data communications; and business and management. C1 NASA,LEWIS RES CTR,MICROGRAV FLUIDS BRANCH,DIV SPACE EXPERIMENTS,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,SPACE VEHICLE PROP BRANCH,DIV SPACE PROP TECHNOL,CLEVELAND,OH 44135. RP BAILEY, SG (reprint author), NASA,LEWIS RES CTR,PHOTOVOLTA BRANCH,DIV POWER TECHNOL,CLEVELAND,OH 44135, USA. NR 24 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1994 VL 31 IS 2 BP 330 EP 338 DI 10.2514/3.26442 PG 9 WC Engineering, Aerospace SC Engineering GA NG692 UT WOS:A1994NG69200028 ER PT J AU STARK, GE KERN, LC VOWELL, CW AF STARK, GE KERN, LC VOWELL, CW TI A SOFTWARE METRIC SET FOR PROGRAM MAINTENANCE MANAGEMENT SO JOURNAL OF SYSTEMS AND SOFTWARE LA English DT Article ID RELIABILITY-ANALYSIS AB Managers at the National Aeronautics and Space Administration's Mission Operations Directorate at the Johnson Space Center wanted to increase their insight into the cost, schedule, and quality of the software-intensive systems maintained for the space shuttle programs. To support this objective, we defined and implemented a software metrics set that contains 13 metrics related to corrective and adaptive maintenance actions. Management support and tools were necessary for effective implementation. The start-up cost was low because much of the data were already collected by the projects. Management's ability to assess and predict the state of software maintenance processes has increased. Managers have taken actions to improve software quality and reduce software maintenance costs based on analysis of the metrics data. C1 MITRE CORP,HOUSTON,TX. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 30 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0164-1212 J9 J SYST SOFTWARE JI J. Syst. Softw. PD MAR PY 1994 VL 24 IS 3 BP 239 EP 249 DI 10.1016/0164-1212(94)90066-3 PG 11 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA NB405 UT WOS:A1994NB40500004 ER PT J AU ZUCKERWAR, AJ NGO, KCT AF ZUCKERWAR, AJ NGO, KCT TI MEASURED 1/F NOISE IN THE MEMBRANE MOTION OF CONDENSER MICROPHONES SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB An acoustic isolation vessel described previously [K. C. T. Ngo and A. J. Zuckerwar, J. Acoust. Sec. Am. 93, 2974-2980 (1993)] has been employed to investigate the background noise in condenser microphones over the frequency range from 2 Hz to 25.6 kHz. Measurements were conducted on five B&K condenser microphones ranging from 1/8 in. to 1 in. diameter and representing both pressure and free field types. The experimental evidence reveals the existence of a purely mechanical 1/f noise component in the membrane motion of condenser microphones. The level of significance for the tested microphones, based on the t statistic, ranges from 0.985 to 0.999. It is found that the membrane 1/f coefficient correlates very well with the air layer resistance RA, which is responsible for the membrane damping. The theoretical implications of the existence of 1/f noise in the damped motion of vibrating systems are discussed. C1 OLD DOMINION UNIV,NORFOLK,VA 23508. RP ZUCKERWAR, AJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 17 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 1994 VL 95 IS 3 BP 1419 EP 1425 DI 10.1121/1.408583 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA NA773 UT WOS:A1994NA77300023 ER PT J AU PFLUG, LA IOUP, GE IOUP, JW FIELD, RL AF PFLUG, LA IOUP, GE IOUP, JW FIELD, RL TI PREFILTERING FOR IMPROVED CORRELATION DETECTION OF BAND-LIMITED TRANSIENT SIGNALS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID HIGHER-ORDER CORRELATIONS; DETERMINISTIC TRANSIENTS; SPECTRA; BISPECTRUM; NOISE AB Prefiltering, or limiting the passband of a received signal, can be used to improve ordinary correlation threshold detector performance for an unknown source model. For the known source model, the cross-correlation detector is equivalent to matched filtering, and intrinsically contains prefiltering. Prefiltering also improves higher-order correlation threshold detector performance, but often with more advantage than seen in the ordinary correlation detector. This is true for both the unknown and known source models. Geometric interpretations are given to provide insight into the origin of potential higher-order advantage. Eight energy signals, each with three different Fourier magnitude-based filters, are used to test the cross-correlation, bicorrelation, and tricorrelation detectors by Monte Carlo simulation and hypothesis testing. Significant signal-to-noise ratio (SNR) gains are evident for both the known and unknown source models with the tricorrelation exhibiting the largest gains. The tricorrelation detector has superior performance versus the cross-correlation detector for all the eight test signals in the unknown source case, and was superior for seven of the eight test signals in the known source case. For the narrow pulse test signal, a probability of detection of 0.5 at probability of false alarm 0.001 was achieved at a power SNR -23.57 dB in the known source model, and at SNR -20.28 dB in the unknown source model. Some other test signals have lower SNRs in the unknown source model. Higher-order detectors can be limited to have equivalent information to that of the ordinary correlation detector. An example illustrating this case is given. C1 UNIV NEW ORLEANS,DEPT PHYS,NEW ORLEANS,LA 70148. RP PFLUG, LA (reprint author), STENNIS SPACE CTR,NAVAL RES LAB,BAY ST LOUIS,MS 39529, USA. NR 23 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 1994 VL 95 IS 3 BP 1459 EP 1473 DI 10.1121/1.408587 PG 15 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA NA773 UT WOS:A1994NA77300028 ER PT J AU BROADHEAD, MK ALI, HB BIBEE, LD AF BROADHEAD, MK ALI, HB BIBEE, LD TI SHEAR-Q ESTIMATES FROM INTERFACE WAVES IN MARINE-SEDIMENTS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Letter AB Scholte wave arrivals at two diverse test sites were analyzed with the spectral ratio method to obtain estimates of average shear e of deep sea bottom sediments. The Scholte waves were generated by bottom-located explosive charges and recorded on ocean bottom seismometers. The results obtained are compared to Q estimates reported in the literature. RP BROADHEAD, MK (reprint author), STENNIS SPACE CTR,NAVAL RES LAB,MISSISSIPPI STATE,MS 39529, USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 1994 VL 95 IS 3 BP 1650 EP 1653 DI 10.1121/1.408551 PG 4 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA NA773 UT WOS:A1994NA77300046 ER PT J AU CHOI, SR SALEM, JA AF CHOI, SR SALEM, JA TI THERMAL-SHOCK BEHAVIOR OF SILICON-NITRIDE FLEXURE BEAM SPECIMENS WITH INDENTATION CRACKS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Note ID CERAMICS; RESISTANCE AB The experimental results of thermal shock testing of silicon nitride flexure beam specimens containing indentation cracks are presented. The thermal stress induced by water quenching is much greater in the transverse direction than in the longitudinal direction, resulting in an insensitivity of residual bend strength to temperature differences up to 580-degrees-C. This result indicates that a flexure beam configuration is not an appropriate geometry for thermal shock testing when thermal shock behavior is to be evaluated from residual bend strength data. RP CHOI, SR (reprint author), NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 12 TC 9 Z9 9 U1 0 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAR PY 1994 VL 77 IS 3 BP 835 EP 838 DI 10.1111/j.1151-2916.1994.tb05374.x PG 4 WC Materials Science, Ceramics SC Materials Science GA NB055 UT WOS:A1994NB05500035 ER PT J AU MILES, T GROSE, WL REMSBERG, EE LINGENFELSER, G AF MILES, T GROSE, WL REMSBERG, EE LINGENFELSER, G TI EVOLUTION OF THE SOUTHERN-HEMISPHERE SUBPOLAR MIDDLE ATMOSPHERE DURING SUMMER AND AUTUMN SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MODE ROSSBY WAVES; LIMB INFRARED MONITOR; LOWER STRATOSPHERE; PLANETARY-WAVES; NIMBUS-7 LIMS; LOWER THERMOSPHERE; GRAVITY-WAVES; WINDS; OZONE; MESOSPHERE AB The evolution of zonal wind and zonal wavenumber one (wave 1) in the Southern Hemisphere subpolar middle atmosphere is described for the period December 1978-May 1979 using temperature and ozone measurements from the Limb Infrared Monitor of the Stratosphere (LIMS) experiment. In late December maximum zonal easterlies of approximately -70 m s-1 are observed at 0.1 mb, 60-degrees-S. A zonal flow reversal occurs during late February and westerlies subsequently increase to 60-70 m s-1 in the upper stratosphere by April-May. LIMS zonal winds are compared with rocketsonde measurements and nadir sounder (derived) winds for summer and autumn. Although quantitative agreement is found at stratospheric levels, substantial discrepancies are evident in the mesosphere, most likely a reflection of sampling and resolution differences in the respective datasets. Stationary and traveling wave 1 temperature disturbances (amplitudes approximately 1-2 K at 60-degrees-S) are observed by LIMS during summer. The stationary wave is confined to the lower stratosphere near the level of zero zonal-mean wind flow, whereas the traveling wave is prominent in the middle stratosphere, moves west at a rate similar to the zonal-mean wind, and exhibits a vertical-meridional structure similar to a P4(1) normal mode Rossby wave. A substantial intensification of wave 1 activity occurs during autumn (amplitudes approximately 5-10 K), which is found to be associated with an upward-directed Eliassen-Palm flux near the subpolar tropopause level. Evidence relating wave 1 activity in the lower-middle stratosphere to the occurrence of zonal ozone perturbations of 10%-20% amplitude is presented for summer and autumn. C1 SCI APPLICAT INT CORP,HAMPTON,VA. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP MILES, T (reprint author), HUGHES STX CORP,7701 GREENBELT RD,GREENBELT,MD 20770, USA. NR 73 TC 11 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 1994 VL 51 IS 5 BP 677 EP 693 DI 10.1175/1520-0469(1994)051<0677:EOTSHS>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NB649 UT WOS:A1994NB64900001 ER PT J AU ALLISON, M DELGENIO, AD ZHOU, W AF ALLISON, M DELGENIO, AD ZHOU, W TI ZERO POTENTIAL VORTICITY ENVELOPES FOR THE ZONAL-MEAN VELOCITY OF THE VENUS TITAN ATMOSPHERES SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MERIDIONAL CIRCULATION; SYMMETRIC STABILITY; GRAVITY-WAVES; THERMAL TIDES; MODEL; SUPERROTATION; DYNAMICS; WINDS; MAINTENANCE; INSTABILITY AB The diagnostic analysis of numerical simulations of the Venus/Titan wind regime reveals an overlooked constraint upon the latitudinal structure of their zonal-mean angular momentum. The numerical experiments, as well as the limited planetary observations, are approximately consistent with the hypothesis that within the latitudes bounded by the wind maxima the total Ertel potential vorticity associated with the zonal-mean motion is approximately well mixed with respect to the neutral equatorial value for a stable circulation. The implied latitudinal profile of angular momentum is of the form M less-than-or-equal-to M(e)(cos lambda)2/Ri, where lambda is the latitude and Ri the local Richardson number, generally intermediate between the two extremes of uniform angular momentum (Ri --> infinity) and uniform angular velocity (Ri = 1). The full range of angular momentum profile variation appears to be realized within the observed meridional-vertical structure of the Venus atmosphere, at least crudely approaching the implied relationship between stratification and zonal velocity there. While not itself indicative of a particular eddy mechanism or specific to atmospheric superrotation, the zero potential vorticity (ZPV) constraint represents a limiting bound for the eddy-mean flow adjustment of a neutrally stable baroclinic circulation and may be usefully applied to the diagnostic analysis of future remote sounding and in situ measurements from planetary spacecraft. C1 HUGHES STX CORP,INST SPACE STUDIES,NEW YORK,NY. RP ALLISON, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,G155,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Del Genio, Anthony/D-4663-2012 OI Del Genio, Anthony/0000-0001-7450-1359 NR 38 TC 27 Z9 27 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 1994 VL 51 IS 5 BP 694 EP 702 DI 10.1175/1520-0469(1994)051<0694:ZPVEFT>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NB649 UT WOS:A1994NB64900002 ER PT J AU SUI, CH LAU, KM TAO, WK SIMPSON, J AF SUI, CH LAU, KM TAO, WK SIMPSON, J TI THE TROPICAL WATER AND ENERGY CYCLES IN A CUMULUS ENSEMBLE MODEL .1. EQUILIBRIUM CLIMATE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NUMERICAL-SIMULATION; MESOSCALE PROCESSES; SOLAR-RADIATION; CLOUD ENSEMBLE; PARAMETERIZATION; CONVECTION; DYNAMICS; ABSORPTION; FEEDBACK; BUDGET AB A cumulus ensemble model is used to study the tropical water and energy cycles and their role in the climate system. The model includes cloud dynamics, radiative processes, and microphysics that incorporate all important production and conversion processes among water vapor and five species of hydrometeors. Radiative transfer in clouds is parameterized based on cloud contents and size distributions of each bulk hydrometeor. Several model integrations have been carried out under a variety of imposed boundary and large-scale conditions. In Part I of this paper, the primary focus is on the water and heat budgets of the control experiment, which is designed to simulate the convective-radiative equilibrium response of the model to an imposed vertical velocity and a fixed sea surface temperature at 28-degrees-C. The simulated atmosphere is conditionally unstable below the freezing level and close to neutral above the freezing level. The equilibrium water budget shows that the total moisture source, M(s), which is contributed by surface evaporation (0.24 M(s)) and the large-scale advection (0.76 M(s)), all converts to mean surface precipitation P(s)BAR. Most of M(s) is transported vertically in convective regions where much of the condensate is generated and falls to surface (0.68 P(s)BAR). The remaining condensate detrains at a rate of 0.48 P(s)BAR and constitutes 65% of the source for stratiform clouds above the melting level. The upper-level stratiform cloud dissipates into clear environment at a rate of 0.14 P(s)BAR, which is a significant moisture source comparable to the detrained water vapor (0.15 P(s)BAR) to the upper troposphere from convective clouds. In the lower troposphere, stratiform clouds evaporate at a rate of 0.41 P(s)BAR, which is a more dominant moisture source than surface evaporation (0.22 P(s)BAR). The precipitation falling to the surface in the stratiform region is about 0.32 P(s)BAR. The associated latent heating in the water cycle is the dominant source in the heat budget that generates a net upward motion in convective regions, upper stratiform regions (above the freezing level), and a downward motion in the lower stratiform regions. The budgets reveal a cycle of water and energy resulted from radiation-dynamic-convection interactions that maintain the equilibrium of the atmosphere. RP SUI, CH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 913,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012; OI Lau, William /0000-0002-3587-3691; SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 41 TC 174 Z9 186 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 1994 VL 51 IS 5 BP 711 EP 728 DI 10.1175/1520-0469(1994)051<0711:TTWAEC>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA NB649 UT WOS:A1994NB64900004 ER PT J AU DUBICK, MA WADE, CE AF DUBICK, MA WADE, CE TI A REVIEW OF THE EFFICACY AND SAFETY OF 7.5-PERCENT NACL 6-PERCENT DEXTRAN-70 IN EXPERIMENTAL-ANIMALS AND IN HUMANS SO JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE LA English DT Review ID HYPERTONIC SALINE DEXTRAN; UNCONTROLLED HEMORRHAGIC-SHOCK; SMALL-VOLUME RESUSCITATION; NACL/6-PERCENT DEXTRAN-70; SODIUM-CHLORIDE; ANESTHETIZED SWINE; TRAUMATIC SHOCK; CONSCIOUS SWINE; BLOOD-FLOW; INFUSION AB Recent years have seen a renewed interest in the use of hypertonic-hyperoncotic solutions as plasma volume expanders for the treatment of hemorrhagic hypotension. In particular, a number of studies in experimental animals have addressed the efficacy and safety of small-volume infusions of 7.5% NaCl/6% dextran 70 (HSD). Employing models of fixed volume or fixed pressure hemorrhage, HSD has improved survival and reversed many of the hemodynamic, hormonal, and metabolic abnormalities associated with hemorrhagic shock. In the few human field trials completed to date, HSD has been shown to be potentially beneficial in hypotensive trauma patients who require surgery or have concomitant head injury. Extensive toxicologic evaluations and lack of reports of adverse effects in the human trials indicate that, at the proposed therapeutic dose of 4 mL/kg, HSD should present little risk. C1 LETTERMAN ARMY INST RES,DIV MIL TRAUMA RES,SAN FRANCISCO,CA 94129. NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 78 TC 73 Z9 76 U1 4 U2 4 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 1079-6061 J9 J TRAUMA JI J. Trauma-Injury Infect. Crit. Care PD MAR PY 1994 VL 36 IS 3 BP 323 EP 330 DI 10.1097/00005373-199403000-00007 PG 8 WC Critical Care Medicine; Surgery SC General & Internal Medicine; Surgery GA NC960 UT WOS:A1994NC96000007 PM 7511708 ER PT J AU THAKOOR, S MASERJIAN, J AF THAKOOR, S MASERJIAN, J TI PHOTORESPONSE PROBE OF THE SPACE-CHARGE DISTRIBUTION IN FERROELECTRIC LEAD-ZIRCONATE-TITANATE THIN-FILM MEMORY CAPACITORS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID POLARIZATION AB A photoresponse study of sol-gel derived polycrystalline thin films of lead zirconate titanate (PZT) is described. Thin film ferroelectric capacitors were fabricated in a sandwich geometry with a transparent top electrode, and illuminated with almost-equal-to 365 nm wavelength (PZT band gap approximately 3.5 eV) light pulses. The observed photocurrent has two components: first, a transient spike coincident with the onset of the illumination pulse, and second, a steady dc photocurrent which prevails as long as the light is ''ON.'' The steady current response exhibits a weak dependence on the polarization, whereas the transient response exhibits a distinct polarization dependence. To understand the nature of this photoresponse we have studied the variation of the photoresponse as a function of the duration of the ''write'' pulse used to program the ferroelectric capacitor. The peak value of the polarization dependent transient component of the photoresponse relates to the injected space charge and the distribution of deep traps within the ferroelectric thin film. This, in turn, is modulated by the duration of the write pulse used to program the capacitor. We provide a space charge model that offers a framework for interpreting the photoresponse. The transient photoresponse thus serves as a qualitative measure of the space charge in the ferroelectric film, and to a limited extent, an indirect measure of the remanent polarization. We propose that these photoresponse effects can be applied as diagnostic probes of the space charge distribution in the ferroelectric thin film. RP THAKOOR, S (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 23 TC 19 Z9 19 U1 1 U2 3 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 MAR-APR PY 1994 VL 12 IS 2 BP 295 EP 299 DI 10.1116/1.578871 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA NB636 UT WOS:A1994NB63600006 ER PT J AU LEE, HP SZALKOWSKI, FJ SATO, DL LIU, X RANALLI, E GEORGE, T AF LEE, HP SZALKOWSKI, FJ SATO, DL LIU, X RANALLI, E GEORGE, T TI NOVEL INTEGRATION OF A GROUP IV ELECTRON-BEAM DEPOSITION CAPABILITY WITH A III-V MOLECULAR-BEAM EPITAXY SYSTEM SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 13th North American Conference on Molecular-Beam Epitaxy CY SEP 13-15, 1993 CL STANFORD UNIV, STANFORD, CA SP AMER VACUUM SOC HO STANFORD UNIV ID GAAS; SI; GROWTH; FILMS; SUPERLATTICES; LAYERS AB A novel way of integrating epitaxial Si and carbon (C) doping capabilities within an existing solid-source III-V molecular beam epitaxy system by means of electron-beam evaporation is reported. By significantly increasing the Si evaporation rate over conventional effusion cells, this technique offers a practical way of growing high Si content (III-V)-Si alloys and superlattices. The use of GaAs-Si alloys with adjustable lattice constants for GaAs on Si growth with improved crystalline quality over previous methods is also demonstrated. Both uniform layer and delta-doped C in GaAs (p-type concentration up to the mid 10(19)/cm3 range) are demonstrated with carrier mobility comparable to other doping sources. These extended capabilities should find wide applications ranging from material synthesis to III-V devices and technology. C1 JET PROP LAB,PASADENA,CA 91109. RP LEE, HP (reprint author), UNIV CALIF IRVINE,DEPT ELECT & COMP ENGN,IRVINE,CA 92717, USA. NR 19 TC 3 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1994 VL 12 IS 2 BP 1163 EP 1166 DI 10.1116/1.587074 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA NG711 UT WOS:A1994NG71100137 ER PT J AU KAVAYA, MJ AF KAVAYA, MJ TI WHATS IN A NAME SO LASER FOCUS WORLD LA English DT Letter RP KAVAYA, MJ (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ELECTROOPT BRANCH,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAR PY 1994 VL 30 IS 3 BP 53 EP 53 PG 1 WC Optics SC Optics GA NA818 UT WOS:A1994NA81800014 ER PT J AU RAMSEY, BD AUSTIN, RA AF RAMSEY, BD AUSTIN, RA TI X-RAY-DETECTORS PROBE ENERGETIC PROCESSES IN THE UNIVERSE SO LASER FOCUS WORLD LA English DT Article RP RAMSEY, BD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV ASTROPHYS,HUNTSVILLE,AL 35812, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAR PY 1994 VL 30 IS 3 BP S9 EP & PG 0 WC Optics SC Optics GA NA818 UT WOS:A1994NA81800020 ER PT J AU LAI, SHY AF LAI, SHY TI DYNAMIC MODELING AND CONTROL OF A ROTATING PIEZO-BONDED BEAM-MASS SYSTEM SO MECHANICS RESEARCH COMMUNICATIONS LA English DT Article AB A variational finite element method is used to derive the dynamic equations for a high speed rotating beam-mass system with embedded piezoelectric materials. Two piezoelectric layers are attached on the beam surfaces. The layer on the top surface is used for sensing and monitoring. The layer on the bottom surface is used for feedback control. The objective is to develop a simple finite element based dynamic model which can be used for structural characterization, monitoring and control. The structural dynamics introduced by the gyroscopic effect is included in the model. The nodal displacements of the structure are monitored by the output voltage level of the sensing layer. The voltage induced by the sensing layer is negatively fed back to the control layer for the adjustment of nodal displacements. Several simulation examples are presented to validate the effectiveness of the proposed finite element based control model. RP LAI, SHY (reprint author), N CAROLINA AGR & TECH STATE UNIV,NASA,CTR AEROSP RES,CONTROLS & GUIDANCE GRP,GREENSBORO,NC 27411, USA. NR 20 TC 2 Z9 3 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0093-6413 J9 MECH RES COMMUN JI Mech. Res. Commun. PD MAR-APR PY 1994 VL 21 IS 2 BP 181 EP 188 DI 10.1016/0093-6413(94)90090-6 PG 8 WC Mechanics SC Mechanics GA MZ891 UT WOS:A1994MZ89100009 ER PT J AU WEISSMAN, P AF WEISSMAN, P TI WORKSHOP ON COMET SHOEMAKER-LEVY 9 - 1994 JANUARY 10-11, UNIVERSITY-OF-MARYLAND, USA SO METEORITICS LA English DT Letter RP WEISSMAN, P (reprint author), JET PROP LAB,183-601,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAR PY 1994 VL 29 IS 2 BP 151 EP 152 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ND202 UT WOS:A1994ND20200003 ER PT J AU YAMAGUCHI, A TAKEDA, H BOGARD, DD GARRISON, D AF YAMAGUCHI, A TAKEDA, H BOGARD, DD GARRISON, D TI TEXTURAL VARIATIONS AND IMPACT HISTORY OF THE MILLBILLILLIE EUCRITE SO METEORITICS LA English DT Article ID THERMAL METAMORPHISM; EVOLUTION; METEORITES; JUVINAS; AGES AB We have investigated 10 new specimens of the Millbillillie eucrite to study its textures and mineral compositions by electron probe microanalyser and scanning electron microscope. Although originally described as having fine-grained texture, the new specimens show diversity of texture. The compositions (Mg/Fe ratios) of the host pigeonites and augite lamellae are homogeneous, respectively, in spite of the textural variation. In addition to their chemical homogeneity, pyroxenes in coarse and fine-grained clasts are partly inverted to orthopyroxene. Chemical zoning of plagioclase during crystal growth is preserved. This eucrite includes areas of granulitic breccias and impact melts. Large scale textures show a subparallel layering suggesting incomplete mixing and deposition of impact melt and lithic fragments. An Ar-39-Ar-40 age determination for a coarse-grained clast indicates a strong degassing event at 3.55 +/- 0.02 Ga. We conclude that Millbillillie is among the most equilibrated eucrites produced by thermal annealing after impact brecciation. According to the classification of impact breccias, Millbillillie can be classified as a mixture of granulitic breccias and impact melts. The last significant thermal event is characterized by network-like glassy veins that run through clasts and matrices. Consideration of textural observations and requirements for Ar-degassing suggests that the Ar-39-Ar-40 age could in principle date either the earlier brecciation and annealing event or the C1 LOCKHEED ELECTR CO INC,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP YAMAGUCHI, A (reprint author), UNIV TOKYO,FAC SCI,INST MINERAL,TOKYO 113,JAPAN. NR 28 TC 31 Z9 32 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAR PY 1994 VL 29 IS 2 BP 237 EP 245 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ND202 UT WOS:A1994ND20200013 ER PT J AU POLLMANN, KW STODIECK, LS LUTTGES, MW AF POLLMANN, KW STODIECK, LS LUTTGES, MW TI HYDRODYNAMICALLY INDUCED FLUID TRANSFER AND NONCONVECTIVE DOUBLE-DIFFUSION IN MICROGRAVITY SLIDING SOLVENT DIFFUSION CELLS SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID CRYSTAL-GROWTH; PROTEIN; CRYSTALLIZATION AB Microgravity can provide a diffusion-dominated environment for double-diffusion and diffusion -reaction experiments otherwise disrupted by buoyant convection or sedimentation. In sliding solvent diffusion cells, a diffusion interface between two liquid columns is achieved by aligning two offset sliding wells. Fluid in contact with the sliding lid of the cavities is subjected to an applied shear stress. The momentum change by the start/stop action of the well creates an additional hydrodynamical force. In microgravity, these viscous and inertial forces are sufficiently large to deform the diffusion interface and induce hydrodynamic transfer between the wells. A series of KC-135 parabolic flight experiments were conducted to characterize these effects and establish baseline data for microgravity diffusion experiments. Flow visualizations show the diffusion interface to be deformed in a sinusoidal fashion following well alignment. After the wells were separated again in a second sliding movement, the total induced liquid transfer was determined and normalized by rhe well aspect ratio. The normalized transfer decreased linearly with Reynolds number from 3.3 to 4.0 % (w/v) for Re = 0.4 (Stokes flow) to a minimum of 1.0 % for Re = 23 to 30. Reynolds numbers that provide minimum induced transfers are characterized by an interface that is highly deformed and unsuitable for diffusion measurements. Flat diffusion interfaces acceptable for diffusion measurements are obtained with Reynolds numbers on the order of 7 to 10. Microgravity experiments aboard a sounding rocket flight verified counter diffusion of different solutes to be diffusion dominated. Ground control experiments showed enhanced mixing by double-diffusive convection. Careful selection of experimental parameters improves initial conditions and minimizes induced transfer rates. RP POLLMANN, KW (reprint author), UNIV COLORADO,NASA,CCDS,CAMPUS BOX 429,BOULDER,CO 80309, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 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. PD MAR PY 1994 VL 7 IS 1 BP 50 EP 59 PG 10 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA NX484 UT WOS:A1994NX48400009 ER PT J AU BLANCHARD, RC NICHOLSON, JY RITTER, JR AF BLANCHARD, RC NICHOLSON, JY RITTER, JR TI ABSOLUTE ACCELERATION MEASUREMENTS ON STS-50 FROM THE ORBITAL ACCELERATION RESEARCH EXPERIMENT (OARE) SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article AB Orbital Acceleration Research Experiment (OARE) data on STS-50 have been examined in detail during a 2-day time period. Absolute acceleration levels have been derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. During the interval, the tri-axial OARE raw telemetered acceleration measurements have been filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval have been analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z-axis sensitive range scale factors were determined in a separate process using orbiter maneuvers and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter center-of-gravity, which are the aerodynamic signals along each body axis. Results indicate that there is a force being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces have been reexamined, but none produces the observed effect. Thus, it is tentatively concluded that the orbiter is creating the environment observed. At least part of this force is thought to be due to the Flash Evaporator System. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. RP BLANCHARD, RC (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 366,HAMPTON,VA 23681, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 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. PD MAR PY 1994 VL 7 IS 1 BP 60 EP 67 PG 8 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA NX484 UT WOS:A1994NX48400010 ER PT J AU WOLINSKI, KG DOLAN, JF AF WOLINSKI, KG DOLAN, JF TI CONFIDENCE-INTERVALS FOR ORBITAL PARAMETERS DETERMINED POLARIMETRICALLY SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE POLARIZATION; SCATTERING; TECHNIQUES, POLARIMETRIC; BINARIES, GENERAL ID BINARY INCLINATIONS; POLARIZATION; SCATTERING AB Aspin, Simmons & Brown and Simmons, Aspin & Brown have shown that the estimate of the inclination of a binary system derived from polarimetric observations becomes increasingly biased with decreasing statistical precision of the data. These authors have also calculated the statistical uncertainty associated with the value of the inclination derived from polarimetric observations for certain binary inclinations. We calculate the light curves of the two normalized Stokes parameters q and u produced by scattering in a binary star system at every 5-degrees in inclination i, equally spaced from 0-degrees to 90-degrees, For each value of i, Gaussian-distributed noise with variance sigma(p)2 and mean zero is added to the calculated q and u, and the resulting Stokes parameters with noise, q' and u', are used to determine the statistical distribution of the estimates i', lambda'2 (related to the orbital longitude of the scattering region) and OMEGA' (related to the orientation of the major axis of the binary orbit on the plane of the sky). We find that lambda'2 and OMEGA' are not biased at any values of sigma(p)/A (where A is the amplitude of the polarimetric variability) i, and are the best estimates of lambda2 and OMEGA. For each value of sigma(p)/A, we then invert these results to estimate the confidence intervals on the derived parameters in the initial parameter space in which the calculations were done without noise. i.e. in the parameter space of the binary system observed with infinite precision. We present our findings graphically, showing confidence intervals on i, lambda2 and OMEGA given i' for several values of sigma(p)/A ranging from 0.001 to 0.70. These results are then applied to previously published results derived from polarimetric observations. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP WOLINSKI, KG (reprint author), PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907, USA. NR 13 TC 19 Z9 19 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 1 PY 1994 VL 267 IS 1 BP 5 EP 12 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MX879 UT WOS:A1994MX87900005 ER PT J AU BIGGS, JD BAILES, M LYNE, AG GOSS, WM FRUCHTER, AS AF BIGGS, JD BAILES, M LYNE, AG GOSS, WM FRUCHTER, AS TI 2 RADIO PULSARS IN THE GLOBULAR-CLUSTER NGC-6624 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE STARS, INDIVIDUAL, 4U 1820-30; STARS, MAGNETIC FIELDS; PULSARS, INDIVIDUAL, 1820-30A; PULSARS, INDIVIDUAL, 1820-30B; GLOBULAR CLUSTERS, INDIVIDUAL, NGC-6624; X-RAYS, STARS ID MAGNETIC-FIELD DECAY; NEUTRON STARS; 4U 1820-30; PERIOD; DISCOVERY; ORIGIN; BINARY AB We report the discovery and accurate timing measurements of two single radio pulsars in the globular cluster NGC 6624. PSR 1820 - 30A is a 5-ms pulsar that is located close to the low-mass X-ray binary 4U 1820 - 30. It seems that the recently reported radio detection of 4U 1820 - 30 with the VLA is, in fact, that of the pulsar. The observed period and period-derivative of PSR 1820 - 30A make it disturbingly young, and also conflict with the accretion spin-up theory unless acceleration in the cluster potential is largely responsible for the observed period-derivative. This requires that the cluster core lies much closer to the pulsar than has been believed hitherto. Such an explanation may also explain the anomalous orbital period-derivative of 4U 1820 - 30. PSR 1820 - 30B has a pulse period of 378 ms, which is unusually long for a pulsar associated with a globular cluster, and also has an unusually large inferred magnetic field. If the neutron star is primordial, then this suggests that its magnetic field has decreased only slightly, if at all, since its formation. C1 CURTIN UNIV TECHNOL,DEPT APPL PHYS,PERTH,WA 6001,AUSTRALIA. NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASTRON,GREENBELT,MD 20771. RP BIGGS, JD (reprint author), UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. NR 31 TC 45 Z9 45 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 1 PY 1994 VL 267 IS 1 BP 125 EP 128 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MX879 UT WOS:A1994MX87900017 ER PT J AU BALDI, P CHAUVIN, Y AF BALDI, P CHAUVIN, Y TI SMOOTH ONLINE LEARNING ALGORITHMS FOR HIDDEN MARKOV-MODELS SO NEURAL COMPUTATION LA English DT Article ID MAXIMUM-LIKELIHOOD AB A simple learning algorithm for Hidden Markov Models (HMMs) is presented together with a number of variations. Unlike other classical algorithms such as the Baum-Welch algorithm, the algorithms described are smooth and can be used on-line (after each example presentation) or in batch mode, with or without the usual Viterbi most likely path approximation. The algorithms have simple expressions that result from using a normalized-exponential representation for the HMM parameters. All the algorithms presented are proved to be exact or approximate gradient optimization algorithms with respect to likelihood, log-likelihood, or cross-entropy functions, and as such are usually convergent. These algorithms can also be casted in the more general EM (Expectation-Maximization) framework where they can be viewed as exact or approximate GEM (Generalized Expectation-Maximization) algorithms. The mathematical properties of the algorithms are derived in the appendix. C1 CALTECH,DIV BIOL,PASADENA,CA 91125. NET-ID INC,STANFORD,CA 94305. STANFORD UNIV,DEPT PSYCHOL,STANFORD,CA 94305. RP BALDI, P (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 15 TC 34 Z9 35 U1 0 U2 1 PU MIT PRESS PI CAMBRIDGE PA 55 HAYWARD ST JOURNALS DEPT, CAMBRIDGE, MA 02142 SN 0899-7667 J9 NEURAL COMPUT JI Neural Comput. PD MAR PY 1994 VL 6 IS 2 BP 307 EP 318 DI 10.1162/neco.1994.6.2.307 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA PF908 UT WOS:A1994PF90800010 ER PT J AU YUILLE, AL STOLORZ, P UTANS, J AF YUILLE, AL STOLORZ, P UTANS, J TI STATISTICAL PHYSICS, MIXTURES OF DISTRIBUTIONS, AND THE EM ALGORITHM SO NEURAL COMPUTATION LA English DT Article AB We show that there are strong relationships between approaches to optmization and learning based on statistical physics or mixtures of experts. In particular, the EM algorithm can be interpreted as converging either to a local maximum of the mixtures model or to a saddle point solution to the statistical physics system. An advantage of the statistical physics approach is that it naturally gives rise to a heuristic continuation method, deterministic annealing, for finding good solutions. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. INT COMP SCI INST,BERKELEY,CA 94704. SANTA FE INST,SANTA FE,NM 87501. RP YUILLE, AL (reprint author), HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138, USA. NR 13 TC 57 Z9 57 U1 0 U2 1 PU MIT PRESS PI CAMBRIDGE PA 55 HAYWARD ST JOURNALS DEPT, CAMBRIDGE, MA 02142 SN 0899-7667 J9 NEURAL COMPUT JI Neural Comput. PD MAR PY 1994 VL 6 IS 2 BP 334 EP 340 DI 10.1162/neco.1994.6.2.334 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA PF908 UT WOS:A1994PF90800012 ER PT J AU LEATHERWOOD, JD SULLIVAN, BM AF LEATHERWOOD, JD SULLIVAN, BM TI LABORATORY STUDY OF EFFECTS OF SONIC-BOOM SHAPING ON JUDGED LOUDNESS AND ACCEPTABILITY SO NOISE CONTROL ENGINEERING JOURNAL LA English DT Article AB A laboratory study was conducted to determine the effects of signature shaping of outdoor sonic booms on subjective loudness and acceptability. The study utilized the sonic boom simula tor at the Langley Research Center. A wide range of symmetrical, front-shock-minimized signature shapes was investigated together with a limited number of asymmetrical signatures. Subjective loudness judgments were obtained from 60 test subjects by using an eleven-point numerical scale. Acceptability judgments were obtained using the method of constant stimuli. Results were used to assess the relative predictive ability of several noise descriptors, determine the loudness benefits of detailed boom shaping, and derive laboratory sonic boom acceptability criteria. These results indicated that the A-weighted sound exposure level, the Stevens Mark VII perceived level, and the Zwicker loudness level descriptors all performed well. Significant reductions in loudness were obtained by increasing front-shock rise time and/or decreasing front-shock overpressure of the front-shock-minimized signatures. In addition, the asymmetrical signatures were rated to be slightly quieter than the symmetrical front-shock-minimized signatures of equal A-weighted sound exposure levels. However, this result was based on a limited number of asymmetric signatures. The comparison of laboratory acceptability results with acceptability data obtained in more realistic situations also indicated good agreement. RP LEATHERWOOD, JD (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU INST NOISE CONTROL ENG PI POUGHKEEPSIE PA PO BOX 3206 ARLINGTON BRANCH, POUGHKEEPSIE, NY 12603 SN 0736-2501 J9 NOISE CONTROL ENG JI Noise Control Eng. J. PD MAR-APR PY 1994 VL 42 IS 2 BP 59 EP 69 DI 10.3397/1.2827862 PG 11 WC Acoustics; Engineering, Multidisciplinary SC Acoustics; Engineering GA NF801 UT WOS:A1994NF80100004 ER PT J AU BENNETT, HE RATHER, JDG MONTGOMERY, EE AF BENNETT, HE RATHER, JDG MONTGOMERY, EE TI FREE-ELECTRON LASER POWER BEAMING TO SATELLITES AT CHINA LAKE, CALIFORNIA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 15th International Free Electron Laser Conference CY AUG 23-27, 1993 CL NETHERLANDS CONGRESS CTR, HAGUE, NETHERLANDS SP UNIV TWENTE, DEPT APPL PHYS, FOM INST PLASMA PHYS RIJNHUIZEN HO NETHERLANDS CONGRESS CTR AB Laser power beaming of energy through the atmosphere to a satellite can extend its lifetime by keeping the satellite batteries in operating condition longer. An alternate propulsion system utilizing power beaming will also significantly reduce the initial insertion cost of these satellites, which now range up to $160000/kg, for geosynchronous orbit. Elements of the power beaming system are a high power free-electron laser, a large diameter telescope to reduce diffractive losses, an adaptive optic beam conditioning system and possibly a balloon or aerostat carrying a large mirror to redirect the laser beam to the satellite after traversing the earth's atmosphere. China Lake, California has excellent seeing, averages 260 cloud-free days/year, has a large geothermal plant nearby for inexpensive power, the lake for water, and is thus an ideal site for such a laser power beaming system. Technological challenges in building such a system and installing it at China Lake will be discussed. C1 NASA,MARSHAL SPACE FLIGHT CTR,MONTGOMERY,AL 35812. NASA,WASHINGTON,DC 20546. RP BENNETT, HE (reprint author), USN,AIR WARFARE CTR,WEAPONS DIV,CHINA LAKE,CA 93555, USA. NR 14 TC 21 Z9 21 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1994 VL 341 IS 1-3 BP 124 EP 131 DI 10.1016/0168-9002(94)90332-8 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA NA788 UT WOS:A1994NA78800029 ER PT J AU ZIMMERMAN, RL ILA, D SMITH, CC AF ZIMMERMAN, RL ILA, D SMITH, CC TI RESONANT SCATTERING ASSISTED LIGHT-ELEMENT ANALYSIS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 11th International Conference on Ion Beam Analysis (IBA-11) CY JUL 05-09, 1993 CL BALATONFURED, HUNGARY SP KFKI RES INST MAT SCI, KFKI RES INST PARTICLE & NUCL PHYS, COMMISS EUROPEAN COMMUNITIES, IBA-10 NETHERLANDS, NATL COMM TECHNOL DEV HUNGARY, HUNGARIAN ACAD SCI AB The use of H+ beams at a selected low energy allows enhanced detection sensitivity to those atoms which possess resonant scattering. Further improvement is possible by using the simultaneous reduction of the substrate scattering cross section by destructive resonance interference. To show the usefulness of destructive and constructive resonance interference, we have selected two systems: one is a thin film of carbon on a silicon substrate and the other is boron on a carbon substrate. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP ZIMMERMAN, RL (reprint author), ALABAMA A&M UNIV,CTR IRRADIAT MAT,POB 1447,NORMAL,AL 35762, USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1994 VL 85 IS 1-4 BP 68 EP 70 DI 10.1016/0168-583X(94)95788-6 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA NF140 UT WOS:A1994NF14000014 ER PT J AU WANG, YJ SCHOLL, MS AF WANG, YJ SCHOLL, MS TI EXPERIMENTAL INVESTIGATION OF FAR-FIELD DIFFRACTION BY MEANS OF NORMALLY AND NON-NORMALLY ILLUMINATED ELLIPTIC APERTURES OF WAVELENGTH DIMENSION SO OPTICAL ENGINEERING LA English DT Article DE INFRARED TECHNOLOGY; DIFFRACTION MEASUREMENT; DIFFRACTION PATTERN AB Far-field diffraction resulting from elliptical apertures of different sizes is measured. Both normal and oblique angles of incidence on the apertures are investigated. Diffraction patterns from apertures with dimensions much greater than the wavelength agree with the existing theory. However, new diffraction patterns have been found when using an aperture of wavelength dimension. RP WANG, YJ (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 19 TC 7 Z9 7 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 692 EP 696 DI 10.1117/12.159345 PG 5 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000006 ER PT J AU LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM AF LIN, TL PARK, JS GUNAPALA, SD JONES, EW DELCASTILLO, HM TI HETEROJUNCTION INTERNAL PHOTOEMISSION SI0.7GE0.3/SI INFRARED DETECTOR SO OPTICAL ENGINEERING LA English DT Article DE INFRARED TECHNOLOGY; HIP DETECTOR; EMISSION; WAVELENGTH REGIME ID ARRAYS AB Single-layer and multilayer Si0.7Ge0.3/Si heterojunction internal photoemission (HIP) detectors with cutoff wavelengths out to approximately 23 mum have been demonstrated. Near-ideal thermionic emission dark current characteristics and photoresponse at wavelengths up to 20 mum were measured. The cutoff wavelength lambda(c) and emission coefficient C1 of the HIP detectors were determined by the modified Fowler plot at the wavelength regime where the corresponding photon energies were smaller than the Fermi energy (approximately 0.15 eV) of the degenerate Si0.7Ge0.3 layers. Similar optical and thermal potential barriers were obtained. The use of multiple Si0.7Ge0.3/Si layers in the stacked HIP detector structure resulted in a significantly increased emission coefficient C1 compared to the single-layer HIP detectors due to an enhanced internal photoemission efficiency without the loss of IR absorption. RP LIN, TL (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 11 Z9 14 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 716 EP 720 DI 10.1117/12.163403 PG 5 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000009 ER PT J AU BAYARD, DS BOUSSALIS, D AF BAYARD, DS BOUSSALIS, D TI INSTRUMENT POINTING, TRACKING, AND VIBRATION SUPPRESSION USING ZERO ANNIHILATION PERIODIC CONTROL SO OPTICAL ENGINEERING LA English DT Article DE INFRARED TECHNOLOGY; DEADBEAT CONTROL; INSTRUMENT POINTING; TRACKING; VIBRATION SUPPRESSION; NONMINIMUM PHASE AB A new control concept for instrument pointing, tracking, and vibration suppression is introduced based on zero annihilation periodic (ZAP) control. In ZAP control, the control gains vary periodically in time, in sharp contrast to conventional controllers whose control gains are fixed in time. The main advantage is that perfect ''deadbeat'' pointing, tracking, and vibration suppression can be achieved-even in the presence of flexible structural elements and noncolocated actuator and sensor hardware. The deadbeat response has clear advantages for optical instruments that must be held steady and precisely pointed during imaging. The ability of ZAP designs to effectively control noncolocated and nonminimum phase configurations opens up many new possibilities for high-performance instrument pointing, vibration damping, target tracking, and other advanced optics control applications. RP BAYARD, DS (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 737 EP 745 DI 10.1117/12.155384 PG 9 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000013 ER PT J AU STEIMLE, LJ WANG, YJ AF STEIMLE, LJ WANG, YJ TI DEVELOPMENT OF A BROAD-BAND ACHROMATIC TWYMAN-GREEN INTERFEROMETER SO OPTICAL ENGINEERING LA English DT Article DE INFRARED TECHNOLOGY; TWYMAN-GREEN INTERFEROMETER; INTERFERENCE; OPTICAL TESTING; IMAGE QUALITY; BROAD-BAND ACHROMATIC INTERFEROMETER AB A modified Twyman-Green interferometer is in use that makes possible wavefront testing of optical filters at any wavelength from 200 to 1100 nm. The use of mirrors for collimation and pupil imaging makes the instrument achromatic, and therefore the focus is fixed over the entire bandwidth, The beamsplitter and compensator plates are made of fused silica, and the detector is a UV-enhanced CCD TV camera. A tunable monochrometer with a broadband light source permits selection of any wavelength. Fringe distortion, even when the collimating mirror is spherical, is small enough to keep measurement errors within 0.1 wave peak-to-valley over the 2- x 2-in. aperture. C1 HUGHES AIRCRAFT CO,EL SEGUNDO,CA 90245. RP STEIMLE, LJ (reprint author), JET PROP LAB,MS 168-224,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 2 TC 2 Z9 2 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 771 EP 775 DI 10.1117/12.159332 PG 5 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000017 ER PT J AU AUMANN, HH PAGANO, RJ AF AUMANN, HH PAGANO, RJ TI ATMOSPHERIC INFRARED SOUNDER ON THE EARTH OBSERVING SYSTEM SO OPTICAL ENGINEERING LA English DT Article DE INFRARED TECHNOLOGY; TEMPERATURE SOUNDERS; SPECTROMETERS; DETECTOR ARRAYS ID SATELLITE AB Recent breakthroughs in IR detector array and cryocooler technology have made it possible to convert the concepts of optimum, passive, IR sounding to a practical satellite-borne instrument: the Atmospheric Infrared Sounder (AIRS), a grating array IR spectrometer temperature sounder, AIRS, together with the Advanced Microwave Sounding Unit and the Microwave Humidity Sounder, will form a complementary sounding system for the Earth Observing System to be launched in the year 2000. The three instruments are expected to become the new operational sounding system for the National Oceanic and Atmospheric Administration. RP AUMANN, HH (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 13 TC 70 Z9 74 U1 2 U2 7 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 776 EP 784 DI 10.1117/12.159325 PG 9 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000018 ER PT J AU KUO, CP AF KUO, CP TI OPTICAL TESTS OF AN INTELLIGENTLY DEFORMABLE MIRROR FOR SPACE TELESCOPE TECHNOLOGY SO OPTICAL ENGINEERING LA English DT Article DE MIRRORS; ACTUATORS; DISTORTION AB The concept of an actively deformable composite reflector is demonstrated and test verified. The objective of developing such a concept is to correct the low-order long-wavelength distortions in a space reflector. This is achieved by bonding a limited number of piezoelectric ceramic strips to the back face sheet of the reflector. A cryointerferometric test of a 0.5-m retlector with six groups of actuators was performed to verify the concept experimentally. Analysis of and test results for the development of an active deformable composite reflector panel are summarized. RP KUO, CP (reprint author), JET PROP LAB,APPL MECH TECHNOL SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 791 EP 800 DI 10.1117/12.157695 PG 10 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000020 ER PT J AU FAWCETT, SC DRUEDING, TW BIFANO, TG AF FAWCETT, SC DRUEDING, TW BIFANO, TG TI NEUTRAL ION FIGURING OF CHEMICAL-VAPOR-DEPOSITED SIC SO OPTICAL ENGINEERING LA English DT Article DE SILICON CARBIDE; ION FIGURING; OPTICAL FABRICATION; DUCTILE GRINDING; POLISHING AB Ion figuring of optical components is a relatively new technology that can alleviate some of the problems associated with traditional contact polishing. Because the technique is noncontacting, edge distortions and rib structure print through do not occur. This investigation was aimed at determining the effect of ion figuring on surface roughness of previously polished or ductile ground ceramic optical samples. This is the first step in research directed toward the combination of a prefinishing process (ductile grinding or polishing) with ion figuring to produce finished ceramic mirrors. Multiple, chemical vapor deposited silicon carbide (CVD SiC) samples were polished or ductile ground to specular or near-specular roughness. These samples were then characterized to determine topographic surface information. The surface evaluation consisted of stylus profilometry, interferometry, and optical and scanning electron microscopy. The surfaces were then ion machined to depths from 0 to 5 mum. The finished surfaces were characterized to evaluate the effects of the ion-machining process with respect to the previous processing methods and the preexisting subsurface damage. This study provides some of the information required to effectively utilize a combined ductile grinding or polishing with ion machining as a procedure for figuring optical components. C1 BOSTON UNIV,BOSTON,MA 02215. RP FAWCETT, SC (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,OPT SYST BRANCH,EB53,HUNTSVILLE,AL 35812, USA. RI Bifano, Thomas/E-6412-2013 OI Bifano, Thomas/0000-0003-4952-2515 NR 15 TC 7 Z9 7 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1994 VL 33 IS 3 BP 967 EP 974 DI 10.1117/12.157687 PG 8 WC Optics SC Optics GA NA360 UT WOS:A1994NA36000043 ER PT J AU PRICE, RD KING, MD DALTON, JT PEDELTY, KS ARDANUY, PE HOBISH, MK AF PRICE, RD KING, MD DALTON, JT PEDELTY, KS ARDANUY, PE HOBISH, MK TI EARTH-SCIENCE DATA FOR ALL - EOS AND THE EOS DATA AND INFORMATION-SYSTEM SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article C1 NASA,GODDARD SPACE FLIGHT CTR,EOS PROJECT SCI OFF,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,ESDIS PROJECT,GREENBELT,MD 20771. RES & DATA SYST CORP,GREENBELT,MD 20770. RP PRICE, RD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MISSION PLANET EARTH OFF,GREENBELT,MD 20771, USA. RI King, Michael/C-7153-2011 OI King, Michael/0000-0003-2645-7298 NR 9 TC 8 Z9 9 U1 0 U2 0 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 1994 VL 60 IS 3 BP 277 EP 286 PG 10 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA NA959 UT WOS:A1994NA95900003 ER PT J AU BRANNON, DP HILL, CL DAVIS, BA BIRK, RJ AF BRANNON, DP HILL, CL DAVIS, BA BIRK, RJ TI COMMERCIAL REMOTE-SENSING PROGRAM SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article AB The mission of the Commercial Remote Sensing Program (CRSP) Office at NASA's John C. Stennis Space Center is to maximize U.S. industry's exploitation of remote sensing and related space-based technologies and to develop advanced technical responses to spatial information requirements. This mission is accomplished through NASA partnerships with companies to develop remote sensing technology applications in response to market-driven spatial information demands. The program builds private-sector capability to supply economically viable remote sensing solutions. The CRSP conducts market research to identify technology limitations that ultimately drive NASA research and development initiatives. Through its commercial partnerships, the program hopes that market demand and advanced technology solutions will increase the use and reduce the cost of spatial data. This paper describes the CRSP's method of addressing both the demand for spatial information and its specific responses to promote an economically viable U.S. industry. C1 SVERDRUP TECHNOL INC,COMMERCIAL REMOTE SENSING PROGRAM,BAY ST LOUIS,MS 39529. RP BRANNON, DP (reprint author), NASA,COMMERCIAL REMOTE SENSING PROGRAM OFF,BAY ST LOUIS,MS 39529, USA. NR 10 TC 8 Z9 8 U1 0 U2 0 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 1994 VL 60 IS 3 BP 317 EP 330 PG 14 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA NA959 UT WOS:A1994NA95900007 ER PT J AU JENSEN, JR COWEN, DJ HALLS, J NARUMALANI, S SCHMIDT, NJ DAVIS, BA BURGESS, B AF JENSEN, JR COWEN, DJ HALLS, J NARUMALANI, S SCHMIDT, NJ DAVIS, BA BURGESS, B TI IMPROVED URBAN INFRASTRUCTURE MAPPING AND FORECASTING FOR BELLSOUTH USING REMOTE-SENSING AND GIS TECHNOLOGY SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID GEOGRAPHICAL INFORMATION-SYSTEMS; LANDSAT-TM; IMAGERY; FRINGE AB The results of a NASA-sponsored Earth Observations Commercial Applications Program (EOCAP) project conducted by BellSouth Telecommunications, the University of South Carolina, and NASA's Stennis Space Center are described. The goal of this EOCAP project is to incorporate remotely sensed data into a multi-purpose forecasting methodology that will assist BellSouth in its market forecasting activities. The research has concentrated on the evaluation of NASA's Calibrated Airborne Multispectral Scanner data (less-than-or-equal-to 5- by 5-m spatial resolution) and SPOT 20- by 20-m data are sufficient to provide regional information on land-cover change. SPOT 10- by 10-m panchromatic data are useful for updating the urban transportation infrastructure. However, inventorying residential housing stock and estimating population characteristics requires imagery with a spatial resolution of less-than-or-equal-to 5 by 5 m. Several innovative methods based on remotely sensed information and ancillary data stored in geographic information systems are used to predict residential housing and commercial-industrial development. The technology is being tested in several wire centers in South Carolina and will be transferred to BellSouth, who will use the technology to perform more efficient forecasting, marketing, and planning. C1 UNIV NEBRASKA,DEPT GEOG,LINCOLN,NE 68588. SVERDRUP TECHNOL INC,BAY ST LOUIS,MS 39529. NASA,BAY ST LOUIS,MS 39529. BELLSOUTH TELECOMMUN PLANNING DEPT,BIRMINGHAM,AL 35243. RP JENSEN, JR (reprint author), UNIV S CAROLINA,DEPT GEOG,COLUMBIA,SC 29208, USA. NR 25 TC 13 Z9 17 U1 1 U2 4 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 1994 VL 60 IS 3 BP 339 EP 346 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA NA959 UT WOS:A1994NA95900009 ER PT J AU BRAND, HR DEISSLER, RJ AF BRAND, HR DEISSLER, RJ TI STABLE LOCALIZED SOLUTIONS IN NONLINEAR OPTICS WITH LARGE DISSIPATION SO PHYSICA A LA English DT Article ID WEAKLY INVERTED BIFURCATION; TRAVELING-WAVE CONVECTION; BINARY MIXTURE; TRANSMISSION; BISTABILITY; EVOLUTION; SOLITONS; VORTICES; PULSES; FIBERS AB We study the spatio-temporal behavior of the electric field inside a laser with saturable absorber in the good cavity limit. We find that the underlying nonlinear partial differential equation admits stable spatially localized solutions for both the one- and the two-dimensional case. We critically examine similarities and differences with the localized solutions found recently near a weakly inverted bifurcation to traveling waves C1 UNIV BAYREUTH,D-95440 BAYREUTH,GERMANY. NASA,LEWIS RES CTR,INST COMPUTAT MECH PROPULS,CLEVELAND,OH 44135. RP BRAND, HR (reprint author), LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,MS B258,LOS ALAMOS,NM 87545, USA. NR 33 TC 36 Z9 36 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAR 1 PY 1994 VL 204 IS 1-4 BP 87 EP 95 DI 10.1016/0378-4371(94)90419-7 PG 9 WC Physics, Multidisciplinary SC Physics GA NB671 UT WOS:A1994NB67100007 ER PT J AU STRAYER, DM AF STRAYER, DM TI LOW-TEMPERATURE RESEARCH IN MICROGRAVITY SO PHYSICA B LA English DT Article; Proceedings Paper CT 20th International Conference on Low Temperature Physics CY AUG 04-11, 1993 CL EUGENE, OR SP INT UNION PURE & APPL PHYS, AMER PHYS SOC, CITY EUGENE, INT INST REFRIGERAT, INT SCI FDN, JET PROPULS LABS, NATL SCI FDN, USN, OFF NAVAL RES, OXFORD INSTRUMENTS INC, TEKTRONIX INC, UNIV OREGON AB The recent flight of the Lambda Point Experiment has demonstrated the potential for performing precise tests of fundamental theories using low temperature techniques in Earth orbit. NASA's Microgravity Science and Applications Division has established a program of successor experiments to investigate other aspects of condensed matter physics using the same low temperature flight facility. This paper will describe the new investigations that have been chosen for flight experiments, and those selected for ground-based studies that could lead to flight experiments later. The flight facility, which has now flown twice on the shuttle orbiter, will also be described. We shall also describe opportunities for investigators to apply for support of scientific studies that could gain significantly by being performed in a low gravity environment. RP STRAYER, DM (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAR PY 1994 VL 197 IS 1-4 BP 84 EP 94 DI 10.1016/0921-4526(94)90201-1 PG 11 WC Physics, Condensed Matter SC Physics GA NG615 UT WOS:A1994NG61500013 ER PT J AU LIPA, JA SWANSON, DR NISSEN, JA CHUI, TCP AF LIPA, JA SWANSON, DR NISSEN, JA CHUI, TCP TI HEAT-CAPACITY AND THERMAL RELAXATION OF BULK HELIUM VERY NEAR THE LAMBDA POINT SO PHYSICA B LA English DT Article; Proceedings Paper CT 20th International Conference on Low Temperature Physics CY AUG 04-11, 1993 CL EUGENE, OR SP INT UNION PURE & APPL PHYS, AMER PHYS SOC, CITY EUGENE, INT INST REFRIGERAT, INT SCI FDN, JET PROPULS LABS, NATL SCI FDN, USN, OFF NAVAL RES, OXFORD INSTRUMENTS INC, TEKTRONIX INC, UNIV OREGON ID RESOLUTION AB In October 1992 a low temperature experiment was flown on the Space Shuttle in a low earth orbit. The objective of the mission was to measure the heat capacity and thermal conductivity of helium very close to the lambda point with the smearing effect of gravity removed. We report preliminary results from the experiment, and compare them with related measurements performed on the ground. The sample was a sphere of helium 3.5 cm in diameter contained within a copper calorimeter of very high thermal conductivity. The calorimeter was attached to a pair of high-resolution paramagnetic salt thermometers with noise levels in the 10(-10) K range and suspended from a high-stability thermal isolation system. During the mission we found that the resolution of the thermometers was degraded somewhat due to the impact of charged particles. This effect limited the useful resolution of the measurements to about two nanokelvins from the lambda point. The results reported here are limited to about ten nanokelvins from the transition. C1 JET PROP LAB,PASADENA,CA 91109. RP LIPA, JA (reprint author), STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305, USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAR PY 1994 VL 197 IS 1-4 BP 239 EP 248 DI 10.1016/0921-4526(94)90218-6 PG 10 WC Physics, Condensed Matter SC Physics GA NG615 UT WOS:A1994NG61500030 ER PT J AU ELHADY, NM ZANG, TA PIOMELLI, U AF ELHADY, NM ZANG, TA PIOMELLI, U TI APPLICATION OF THE DYNAMIC SUBGRID-SCALE MODEL TO AXISYMMETRICAL TRANSITIONAL BOUNDARY-LAYER AT HIGH-SPEED SO PHYSICS OF FLUIDS LA English DT Article ID LARGE-EDDY SIMULATION; COMPRESSIBLE TURBULENCE; FLOWS AB The subgrid scales are modeled dynamically in a large-eddy simulation of transitional boundary-layer flow along a cylinder at a Mach number of 4.5. The behavior of the dynamic-model coefficients, which is determined from local information in the resolved field, is investigated through both an a priori test with direct numerical simulation data for the same case and a complete large-eddy simulation. Both contractions proposed by Germane ct al. and Lilly are used for the unique determination of the coefficients of the dynamic model, and their results are compared and assessed. The behavior, as well as the energy cascade of the subgrid-scale field structure, is investigated at various stages of the transition process. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. UNIV MARYLAND,DEPT MECH ENGN,COLLEGE PARK,MD 20742. RP ELHADY, NM (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 24 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAR PY 1994 VL 6 IS 3 BP 1299 EP 1309 DI 10.1063/1.868297 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA NE123 UT WOS:A1994NE12300021 ER PT J AU DINAVAHI, SPG PRUETT, CD ZANG, TA AF DINAVAHI, SPG PRUETT, CD ZANG, TA TI DIRECT NUMERICAL-SIMULATION AND DATA-ANALYSIS OF A MACH-4.5 TRANSITIONAL BOUNDARY-LAYER FLOW SO PHYSICS OF FLUIDS LA English DT Article AB This paper describes the creation by temporal direct numerical simulation and the analysis based on the Reynolds stress transport equations of a high quality data set that represents the laminar-turbulent transition of a high-speed boundary-layer flow. Following Pruett and Zang [Theoret. Comput. Fluid Dyn. 3, 345 (1992)], and with the help of algorithmic refinements, the evolution of an axial, Mach 4.5 boundary-layer flow along the exterior of a hollow cylinder is simulated numerically. From a perturbed laminar initial state, the well-resolved simulation proceeds through laminar breakdown to the beginning of a turbulent flow regime. Favre-averaged Reynolds stress transport equations are derived in generalized curvilinear coordinates and are then specialized to the cylindrical geometry at hand. Reynolds stresses and various turbulence quantities, such as turbulent kinetic energy and turbulent Mach number, are calculated from the numerical data at various stages of the transition process. The kinetic energy ''budgets'' are also constructed from the transport equations. Various contributing terms for the evolution of kinetic energy, like the rates of production, dissipation, transport, and diffusion, are presented. The compressible dissipation rate is small in comparison with the solenoidal dissipation rate for all times. The pressure-dilatation term is of the same order of magnitude as the compressible dissipation rate. The authors hope that both the data set and the analysis presented will benefit those who attempt to model high-speed transitional flow. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP DINAVAHI, SPG (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 21 TC 7 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAR PY 1994 VL 6 IS 3 BP 1323 EP 1330 DI 10.1063/1.868300 PG 8 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA NE123 UT WOS:A1994NE12300024 ER PT J AU SHEBALIN, JV AF SHEBALIN, JV TI BROKEN SYMMETRY IN IDEAL MAGNETOHYDRODYNAMIC TURBULENCE SO PHYSICS OF PLASMAS LA English DT Article AB A numerical study of the long-time evolution of a number of cases of inviscid, isotropic, incompressible, three-dimensional fluid, and magnetofluid turbulence has been completed. The results confirm that ideal magnetohydrodynamic turbulence is nonergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation. The broken symmetry manifests itself as a coherent structure, i.e., a nonzero time-averaged part of the turbulent magnetic field. The coherent structure is observed, in one case, to contain about 18% of the total energy. RP SHEBALIN, JV (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 13 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1994 VL 1 IS 3 BP 541 EP 547 DI 10.1063/1.870798 PG 7 WC Physics, Fluids & Plasmas SC Physics GA ND880 UT WOS:A1994ND88000010 ER PT J AU JUNG, YD AF JUNG, YD TI THERMAL AND NONTHERMAL ELECTRON-ION BREMSSTRAHLUNG SPECTRUM FROM HIGH-TEMPERATURE PLASMAS SO PHYSICS OF PLASMAS LA English DT Article AB Electron-ion bremsstrahlung radiation from high-temperature plasmas is investigated. The first- and second-order Coulomb corrections in the nonrelativistic bremsstrahlung radiation power are obtained by the Elwert-Sommerfeld factor. In this paper, two cases of the electron distributions, the thermal and nonthermal power-law distributions, are considered. The inclusion of Coulomb corrections is necessary in deducing correctly the electron distribution function from radiation data. These results provide the correct information of electron distributions in high-temperature plasmas, such as in inertial confinement fusion plasmas and in the astrophysical hot thermal and nonthermal x-ray sources. C1 HANYANG UNIV,DEPT PHYS,KYUNGGI DO 425791,SOUTH KOREA. RP JUNG, YD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES-65,HUNTSVILLE,AL 35812, USA. NR 13 TC 36 Z9 36 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1994 VL 1 IS 3 BP 785 EP 788 DI 10.1063/1.870771 PG 4 WC Physics, Fluids & Plasmas SC Physics GA ND880 UT WOS:A1994ND88000037 ER PT J AU JUNG, YD AF JUNG, YD TI SCREENING MODIFICATION ON THE TRAJECTORY OF THE PROJECTILE ELECTRON IN THE ELECTRON-ION EXCITATION IN DENSE-PLASMAS SO PHYSICS OF PLASMAS LA English DT Article ID IMPACT EXCITATION; HYDROGENIC IONS; APPROXIMATION AB A behavior of the trajectory of the projectile electron in the electron-impact excitation of hydrogenic ions in dense plasmas is investigated using modified hyperbolic-orbit method in the semiclassical approximation. The interaction potential is obtained by the Debye-Huckel model of the screened Coulomb interaction for the interesting domain of the Debye length LAMBDA/a(Z) greater-than-or-equal-to 10. The screening effects on the eccentricity of the projectile path produce a significant change in the excitation cross section near excitation threshold. The result shows that the trajectory of the projectile electron becomes a hyperbolic path rather than a parabolic path because of the plasma-screening effects. For higher incident energies, the plasma-screening effects on the projectile electron are decreased. C1 HANYANG UNIV,DEPT PHYS,KYUNGGI DO 425791,SOUTH KOREA. RP JUNG, YD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES-65,HUNTSVILLE,AL 35812, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1994 VL 1 IS 3 BP 789 EP 792 DI 10.1063/1.870772 PG 4 WC Physics, Fluids & Plasmas SC Physics GA ND880 UT WOS:A1994ND88000038 ER PT J AU YOON, TS HONEYCUTT, RK KAITCHUCK, RH SCHLEGEL, EM AF YOON, TS HONEYCUTT, RK KAITCHUCK, RH SCHLEGEL, EM TI QUANTITATIVE SPECTRAL TYPES FOR 19 ALGOL SECONDARIES SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID TRANSIENT ACCRETION DISKS; SYSTEMS AB Time-resolved spectra of 19 short-period Algol-type binary star systems obtained during total eclipse are used to derive the temperature spectral class of the mass-losing secondary component. The spectral classifications employed a quantitative comparison of the strengths of absorption features in stars of known spectral class with those of the program stars. The luminosity spectral class cannot be determined from these data, so both main-sequence and giant stars were used for the comparison. Our spectral types are compared with published types and found to be generally in good agreement, unless the published types are derived from the light curves. The photometrically determined types are systematically later than our directly determined types. This effect is shown also to exist in catalogs of Algol parameters. C1 INDIANA UNIV,DEPT ASTRON,BLOOMINGTON,IN 47405. BALL STATE UNIV,DEPT PHYS & ASTRON,MUNCIE,IN 47306. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV SPACE RES ASSOC,COLUMBIA,MD. NR 19 TC 12 Z9 12 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAR PY 1994 VL 106 IS 697 BP 239 EP 243 DI 10.1086/133376 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NB087 UT WOS:A1994NB08700002 ER PT J AU PURGOLD, GC WHITLOCK, CH WHEELER, RJ LECROY, SR AF PURGOLD, GC WHITLOCK, CH WHEELER, RJ LECROY, SR TI A MULTIWAVELENGTH AIRBORNE RADIOMETER SCANNER (ARS) FOR MEASURING SURFACE BIDIRECTIONAL REFLECTANCE CHARACTERISTICS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB The development and application of the Airborne Radiometer Scanner (ARS), a helicopter-borne multiwavelength radiometer scanner to obtain directional reflectance data over natural Earth targets, is reported. The rationale for the methodology used in the design and a detailed description of the instrument are described. Techniques used to maintain a desired heading in cross-winds without introducing unwanted pitch or roll moments into the platform are included. The system overcomes some of the limitations of previous methods used to characterize surface directional reflectance. Samples of results from a pilot experiment conducted over the alkali flats region of the White Sands Missile Range, New Mexico, are briefly reviewed. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA. RP PURGOLD, GC (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MS 483,HAMPTON,VA 23681, USA. NR 7 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR PY 1994 VL 47 IS 3 BP 322 EP 330 DI 10.1016/0034-4257(94)90100-7 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA NN407 UT WOS:A1994NN40700004 ER PT J AU MYNENI, RB ASRAR, G AF MYNENI, RB ASRAR, G TI ATMOSPHERIC EFFECTS AND SPECTRAL VEGETATION INDEXES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID RADIATIVE-TRANSFER; PLANT CANOPIES; INDEX; MODEL; REFLECTANCE; SCATTERING; EQUATION AB A vegetation / atmosphere radiative transfer method is employed to study atmospheric effects in spectral vegetation indices. A one-dimensional turbid medium model of a vegetation canopy that includes specular reflection and the hot spot effect is used to calculate canopy bidirectional reflectance factors. These are then used to specify the lower boundary condition of the atmospheric radiative transfer problem. A horizontally homogeneous cloudless midlatitude continental atmosphere with both molecular and aerosol loading is assumed throughout. The canopy and atmospheric radiative transfer equations are numerically solved by the discrete ordinates method. A total of 13 discrete wavelengths in the solar spectrum outside the absorption bands of major atmospheric constituents were considered in this study. Spectral and angular distribution of surface radiances above the canopy and atmosphere were evaluated for different solar zenith angles and leaf area indices. The most frequently used spectral vegetation index, NDVI, and variants introduced recently to correct for atmospheric and soil brightness effects (ARVI, SAVI, and SARVI) were calculated to investigate the extent of atmospheric distortion. The nature of the relationship between top-of-the-atmosphere and, top-of-the-canopy spectral vegetation indices is studied, and its sensitivity to various problem parameters assessed. C1 NASA HEADQUARTERS,WASHINGTON,DC. RP MYNENI, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. RI Myneni, Ranga/F-5129-2012 NR 33 TC 71 Z9 75 U1 2 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR PY 1994 VL 47 IS 3 BP 390 EP 402 DI 10.1016/0034-4257(94)90106-6 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA NN407 UT WOS:A1994NN40700010 ER PT J AU RULISON, AJ RHIM, WK AF RULISON, AJ RHIM, WK TI A NONCONTACT MEASUREMENT TECHNIQUE FOR THE SPECIFIC-HEAT AND TOTAL HEMISPHERICAL EMISSIVITY OF UNDERCOOLED REFRACTORY MATERIALS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A noncontact measurement technique for the constant pressure specific heat (c(pl)) and the total hemispherical emissivity (epsilon(T1)) of undercooled refractory materials is presented. In purely radiative cooling, a simple formula which relates the post-recalescence isotherm duration and the undercooling level to c(pl) is derived. This technique also allows us to measure epsilon(Tl) once C(pl) is known. The experiments were performed using the high-temperature high-vacuum electrostatic levitator at JPL in which 2-3 mm diameter metallic samples can be levitated, melted, and radiatively cooled in vacuum. The averaged specific heats and total hemispherical emissivities of Zr and Ni over the undercooled regions agree well with the results obtained by drop calorimetry: C(pl,av(Zr)=40.8+/-0.9 J/mol K, epsilon(Tl,av) (Zr)=0.28+/-0.01, c(pl,av)(Ni)=42.6+/-0.8 J/mol K, and epsilon(Tl,av)(Ni)=0.16+/-0.01. RP RULISON, AJ (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 60 Z9 61 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1994 VL 65 IS 3 BP 695 EP 700 DI 10.1063/1.1145087 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA NA930 UT WOS:A1994NA93000025 ER PT J AU GALLERY, J GOUTERMAN, M CALLIS, J KHALIL, G MCLACHLAN, B BELL, J AF GALLERY, J GOUTERMAN, M CALLIS, J KHALIL, G MCLACHLAN, B BELL, J TI LUMINESCENT THERMOMETRY FOR AERODYNAMIC MEASUREMENTS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID FLUORESCENCE; RESOLUTION; FILMS AB A luminescent temperature sensitive paint containing the molecule rhodamine B base in a silicone polymer paint has been developed that utilizes video imaging detection to produce temperature maps of an entire surface from luminescence intensity measurements. The luminescent thermometry system has been calibrated in the laboratory to have an intensity loss of 2.30% per-degrees-C, in the range of 10 to 46-degrees-C, with a root mean square prediction error (RMSPE) of 0.26-degrees-C. To evaluate the technique, transient temperature field measurements have been made on a copper plate with a heater at one end. In spite of a loss in sensitivity of the paint due to aging effects that reduced sensitivity to 1.39% intensity loss per -degrees-C, the calculated RMSPE was 0.25-degrees-C and the time series of temperature profiles predicted from luminescence agree with those predicted by a numerical solution to the heat flow equation. Data was also collected from the surface of an airfoil in a wind tunnel experiment. In spite of systematic temperature differences between the thermocouples used for calibration and the paint, RMSPE's of less than. 1-degrees-C were obtained. C1 NASA,AMES RES CTR,FLUID MECH LAB,MOFFETT FIELD,CA 94035. RP GALLERY, J (reprint author), UNIV WASHINGTON,DEPT CHEM,BG 10,SEATTLE,WA 98195, USA. NR 36 TC 39 Z9 40 U1 0 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1994 VL 65 IS 3 BP 712 EP 720 DI 10.1063/1.1145090 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA NA930 UT WOS:A1994NA93000028 ER PT J AU KYRIAKOPOULOS, KJ SARIDIS, GN AF KYRIAKOPOULOS, KJ SARIDIS, GN TI MINIMUM JERK FOR TRAJECTORY PLANNING AND CONTROL SO ROBOTICA LA English DT Article DE TRAJECTORY; CONTROL ALGORITHM; ROBOTS AB It has been experimentally verified that the jerk of the desired trajectory adversely affects the performance of the tracking control algorithms for robotic manipulators. In this paper, we investigate the reasons behind this effect, and state the trajectory planning problem as an optimization problem that minimizes a norm of joint jerk over a prespecified Cartesian space trajectory. The necessary conditions are derived and a numerical algorithm is presented. RP KYRIAKOPOULOS, KJ (reprint author), RENSSELAER POLYTECH INST,NASA,CTR INTELLIGENT ROBOT SYST SPACE EXPLORAT,TROY,NY 12180, USA. NR 0 TC 6 Z9 7 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0263-5747 J9 ROBOTICA JI Robotica PD MAR-APR PY 1994 VL 12 BP 109 EP 113 PN 2 PG 5 WC Robotics SC Robotics GA NB521 UT WOS:A1994NB52100003 ER PT J AU WHITAKER, AF JANG, BZ AF WHITAKER, AF JANG, BZ TI OXYGEN PLASMA ENVIRONMENT - ITS EFFECT ON POLYMERS SO SAMPE JOURNAL LA English DT Article ID GLOW-DISCHARGE; FILMS AB The response of polymers to atomic oxygen in a radio frequency plasma was investigated. As a first step, an effort was made to characterize the nature of an oxygen plasma. Relative concentrations of various charged and neutral particles were determined. A wide variety of polymeric materials were then exposed to a thermal atomic oxygen environment at fluxes of 10(22) atoms/m2-sec. Bulk material temperatures were maintained at 10, 45, and 75-degrees-C during exposure. Mass loss rate of polymers was primarily controlled by the atomic oxygen species which nonetheless constituted only one percent or less of the total plasma chamber pressure. Ions and electrons which were determined to be minor constituents of the plasma did not contribute to the mass loss. Sputtering by the thermal oxygen atom had essentially no influence in the removal of surface atoms of polymers. Mass loss of polymers under atomic oxygen exposure was confirmed to be a thermally activated process with activation energies in the range from 1 to 48 kJ/mole. Polymer reactions with atomic oxygen may be described by a two-step process of atomic oxygen diffusion into the polymer surface with subsequent reactions with bonds to generate low molecular weight gases. C1 AUBURN UNIV,MAT ENGN PROGRAM,AUBURN,AL 36849. RP WHITAKER, AF (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 41 TC 10 Z9 12 U1 0 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0091-1062 J9 SAMPE J JI Sampe J. PD MAR-APR PY 1994 VL 30 IS 2 BP 30 EP 41 PG 12 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA PJ404 UT WOS:A1994PJ40400006 ER PT J AU FREUND, RW NACHTIGAL, NM AF FREUND, RW NACHTIGAL, NM TI AN IMPLEMENTATION OF THE QMR METHOD BASED ON COUPLED 2-TERM RECURRENCES SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 1992 Copper Mountain Conference on Iterative Methods in Numerical Linear Algebra CY APR 09-14, 1992 CL COPPER MT RESORT, COPPER MT, CO SP US DOE HO COPPER MT RESORT DE KRYLOV SUBSPACE ITERATION; QUASI-MINIMAL RESIDUAL METHOD; NON-HERMITIAN MATRICES; COUPLED 2-TERM RECURRENCES; LOOK-AHEAD TECHNIQUES; COMPLEX SYMMETRICAL MATRICES ID LINEAR-SYSTEMS; MATRICES AB Recently, the authors proposed a new Krylov subspace iteration, the quasi-minimal residual (QMR) algorithm, for solving non-Hermitian linear systems. In the original implementation of the QMR method, the Lanczos process with look-ahead is used to generate basis vectors for the underlying Krylov subspaces. In the Lanczos algorithm, these basis vectors are computed by means of three-term recurrences. It has been observed that, in finite-precision arithmetic, vector iterations based on three-term recursions are usually less robust than mathematically equivalent coupled two-term vector recurrences. This paper presents a look-ahead algorithm that constructs the Lanczos basis vectors by means of coupled two-term recursions. Some implementation details are given, and the look-ahead strategy is described. A new implementation of the QMR method, based on this coupled two-term algorithm, is proposed. A simplified version of the QMR algorithm without look-ahead is also presented, and the special case of QMR for complex symmetric linear systems is considered. Results of numerical experiments comparing the original and the new implementations of the QMR method are reported. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. RP FREUND, RW (reprint author), AT&T BELL LABS,ROOM 2C-420,600 MT AVE,MURRAY HILL,NJ 07974, USA. NR 24 TC 141 Z9 147 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAR PY 1994 VL 15 IS 2 BP 313 EP 337 DI 10.1137/0915022 PG 25 WC Mathematics, Applied SC Mathematics GA MZ036 UT WOS:A1994MZ03600006 ER PT J AU SPANIER, J MAIZE, EH AF SPANIER, J MAIZE, EH TI QUASI-RANDOM METHODS FOR ESTIMATING INTEGRALS USING RELATIVELY SMALL SAMPLES SO SIAM REVIEW LA English DT Article DE QUASI-MONTE-CARLO; ASYMPTOTIC RATE OF CONVERGENCE; NUMERICAL INTEGRATION ID PSEUDO-RANDOM NUMBERS; MONTE-CARLO; DIMENSION AB Much of the recent work dealing with quasi-random methods has been aimed at establishing the best possible asymptotic rates of convergence to zero of the error resulting when a finite-dimensional integral is replaced by a finite sum of intergrand values. In contrast with this perspective to concentrate on asymptotic convergence rates, this paper emphasizes quasi-random methods that are effective for all sample sizes. Throughout the paper, the problem of estimating finite-dimensional integrals is used to illustrate the major ideas, although much of what is done applies equally to the problem of solving certain Fredholm integral equations. Some new techniques, based on error-reducing transformations of the integrand, are described that have been shown to be useful both in estimating high-dimensional integrals and in solving integral equations. These techniques illustrate the utility of carrying over to the quasi-Monte Carlo method certain devices that have proven to be very valuable in statistical (pseudorandom) Monte Carlo applications. C1 JET PROP LAB,PASADENA,CA 91109. RP SPANIER, J (reprint author), CLAREMONT GRAD SCH,CLAREMONT,CA 91711, USA. NR 75 TC 61 Z9 62 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD MAR PY 1994 VL 36 IS 1 BP 18 EP 44 DI 10.1137/1036002 PG 27 WC Mathematics, Applied SC Mathematics GA NE149 UT WOS:A1994NE14900003 ER PT J AU VINCENT, KR CHADWICK, OA AF VINCENT, KR CHADWICK, OA TI SYNTHESIZING BULK-DENSITY FOR SOILS WITH ABUNDANT ROCK FRAGMENTS SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article; Proceedings Paper CT 58th Annual Meeting of the Soil-Science-Society-of-America CY NOV 13-18, 1994 CL SEATTLE, WA SP SOIL SCI SOC AMR ID IRREGULAR HOLE AB Bulk density is a fundamental soil property that is difficult to determine for gravelly to extremely gravelly soils because results vary significantly with sample volume. For such coarse soils, the representative volume (for whole-soil bulk density) should be large, but guidelines for selecting an appropriate sample volume do not exist. We evaluated the representative volume for a soil with abundant rock fragments, by comparing measured properties of samples ranging in volume from 0.03 to 410 L. For whole-soil bulk density determination, the representative volume is 4 L or larger for a soil horizon containing 34% (v/v) gravel and is between 5 and 50 L for a soil horizon containing 54% gravel. Intact samples of that size are prohibitively large, so we developed an alternative approach that starts with measurement of whole-soil bulk density. For fine-earth bulk density, the sample volume needed for representative results is between 0.2 and 1 L for gravelly to extremely gravelly soils. The alternative approach reliably synthesizes whole-soil bulk density using (i) fine-earth bulk density from modest-sized samples, (ii) mass-size distribution from large (>40 kg) representative disturbed samples, and (iii) rock fragment bulk densities. The mass and volume of rock fragments that should be in a sample are added to the mass and volume used to calculate fine-earth bulk density. This method allows integration of lateral variability in the soil without the consequence of averaging properties across a large depth range. C1 JET PROP LAB,PASADENA,CA 91109. RP VINCENT, KR (reprint author), UNIV ARIZONA,DEPT GEOSCI,TUCSON,AZ 85721, USA. NR 14 TC 36 Z9 37 U1 1 U2 11 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAR-APR PY 1994 VL 58 IS 2 BP 455 EP 464 PG 10 WC Soil Science SC Agriculture GA NG629 UT WOS:A1994NG62900030 ER PT J AU SCHMIEDER, B HAGYARD, MJ AI, GX ZHANG, HQ KALMAN, B GYORI, L ROMPOLT, B DEMOULIN, P MACHADO, ME AF SCHMIEDER, B HAGYARD, MJ AI, GX ZHANG, HQ KALMAN, B GYORI, L ROMPOLT, B DEMOULIN, P MACHADO, ME TI RELATIONSHIP BETWEEN MAGNETIC-FIELD EVOLUTION AND FLARING SITES IN AR-6659 IN JUNE 1991 SO SOLAR PHYSICS LA English DT Article ID SOLAR-FLARES; FLUX EMERGENCE; ACTIVE REGION; NORTH DIRECTION; RECONNECTION AB During the international campaign of June 1991, the active region AR 6659 produced six very large, long-duration flares (X10/12) during its passage across the solar disk. We present the characteristics of four of them (June 4, 6, 9, 15). Precise measurements of the spot motions from Debrecen and Tokyo white-light pictures are used to understand the fragmentation of the main sunspot group with time. This fragmentation leads to a continuous restructuring of the magnetic field pattern while rapid changes are evidenced due to fast new flux emergence (magnetograms of MFSC, Huairou). The first process leads to a shearing of the field lines along which there is energy storage; the second one is the trigger which causes the release of energy by creating a complex topology. We conjecture that these two processes with different time scales are relevant to the production of flares. C1 NASA,MSFC,HUNTSVILLE,AL 35812. BEIJING OBSERV,BEIJING 100080,PEOPLES R CHINA. HUNGARIAN ACAD SCI,HELIOPHYS OBSERV,H-4010 DEBRECEN,HUNGARY. WROCLAW UNIV,INST ASTRON,PL-51622 WROCLAW,POLAND. UAH,HUNTSVILLE,AL 35899. RP SCHMIEDER, B (reprint author), OBSERV PARIS,URA 326,CNRS,F-92195 MEUDON,FRANCE. OI Demoulin, Pascal/0000-0001-8215-6532 NR 35 TC 61 Z9 66 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAR PY 1994 VL 150 IS 1-2 BP 199 EP 219 DI 10.1007/BF00712886 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NF002 UT WOS:A1994NF00200014 ER PT J AU MILLER, RL CRUISE, JF OTERO, E LOPEZ, JM AF MILLER, RL CRUISE, JF OTERO, E LOPEZ, JM TI MONITORING SUSPENDED PARTICULATE MATTER IN PUERTO-RICO - FIELD-MEASUREMENTS AND REMOTE-SENSING SO WATER RESOURCES BULLETIN LA English DT Article DE COASTAL AREAS; SUSPENDED PARTICULATE MATTER; REMOTE SENSING ID PHYTOPLANKTON PRODUCTIVITY; DIURNAL PERIODICITY; ESTUARIES; SEDIMENT; PHOTOSYNTHESIS; TEMPERATURE; IRRADIANCE; SALINITY; GROWTH; MODEL AB The spatial distribution of suspended particulate matter (SPM) was estimated in Mayaguez Bay on the west coast of Puerto Rico by using traditional ship board measurements and remotely sensed data acquired over four days during January 1990. This effort was part of a joint project between NASA and the University of Puerto Rico to develop techniques to monitor the water quality of a Caribbean coastal zone. This paper presents the methods and algorithms developed to map and analyze short term changes in the source and spatial distribution of SPM in Mayaguez Bay by using remotely sensed data acquired by the Calibrated Airborne Multispectral Scanner (CAMS). A PC-based data acquisition system was developed to record continuous ship measurements of select in- water variables. Spectral reflectances derived from CAMS red and near-IR data were corrected for atmospheric effects and then used to generate maps of SPM. These maps displayed SPM plumes associated with the mouths of the bay's three river systems. Significant day-to-day differences in the spatial characteristics were observed, suggesting that changes in river discharge occurred. However, an analysis of estimated river discharge, sediment yield, local wind field, and thermal river plume indicates that observed sediment plumes result primarily from wind-driven resuspension events. C1 UNIV PUERTO RICO,DEPT MARINE SCI,MAYAGUEZ,PR 00708. LOUISIANA STATE UNIV,DEPT CIVIL & ENVIRONM ENGN,BATON ROUGE,LA 70803. RP MILLER, RL (reprint author), NASA,EARTH OBSERVAT PROJECTS OFF,JA20 BLDG 1100,BAY ST LOUIS,MS 39529, USA. NR 32 TC 4 Z9 4 U1 1 U2 3 PU AMER WATER RESOURCES ASSOC PI HERNDON PA 950 HERNDON PARKWAY SUITE 300, HERNDON, VA 20170-5531 SN 0043-1370 J9 WATER RESOUR BULL JI Water Resour. Bull. PD MAR-APR PY 1994 VL 30 IS 2 BP 271 EP 282 PG 12 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA NJ819 UT WOS:A1994NJ81900010 ER PT J AU CRAGO, RD BRUTSAERT, W AF CRAGO, RD BRUTSAERT, W TI THE ESTIMATION OF SURFACE MOMENTUM FLUX UNDER UNSTABLE CONDITIONS FROM THE ATMOSPHERIC-PRESSURE FIELD SO WATER RESOURCES RESEARCH LA English DT Article ID PLANETARY BOUNDARY-LAYER; TEMPERATURE; STABILITY; FIFE AB Data from FIFE (the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment) were used in an atmospheric boundary layer bulk similarity formulation to derive values of the friction velocity, u* (i.e., the shear stress), from surface geostrophic wind measurements under unstable conditions. Several stability-dependent forms for the similarity functions B (corresponding to the x direction geostrophic wind, u(g)) and B(w) (corresponding to the scalar geostrophic wind speed, G) were tested. Formulations to calculate u* from G were more successful than those which used only u(g). However, the dependency of B, B(w), or the geostrophic drag coefficient, C(G) = mu*/G, on either stability or baroclinicity was observed to be relatively weak. For FIFE, a constant value of B(w) = 1.99 agreed with the reference u* values almost as well as the best stability-dependent formulations. A constant value Of C(G) = 0.0883, used with measured values of G, gave an unbiased estimate of u*, on average, with a correlation r = 0.80. C1 CORNELL UNIV,SCH CIVIL & ENVIRONM ENGN,ITHACA,NY 14853. RP CRAGO, RD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,CODE 974,GREENBELT,MD 20771, USA. NR 25 TC 3 Z9 3 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1994 VL 30 IS 3 BP 617 EP 623 DI 10.1029/93WR02921 PG 7 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA NA853 UT WOS:A1994NA85300003 ER PT J AU WADAS, A MORELAND, J RICE, P KATTI, RR AF WADAS, A MORELAND, J RICE, P KATTI, RR TI MAGNETIC FORCE MICROSCOPY IMAGES OF MAGNETIC GARNET WITH THIN-FILM MAGNETIC TIP SO APPLIED PHYSICS LETTERS LA English DT Article AB We present magnetic force microscopy images of YGdTmGa/YSmTmGa magnetic garnet, using a thin magnetic film deposited on Si3N5 atomic force microscopy tips. We have found correlations between the topography and the magnetic domain structure. We show that by using either magnetized Fe-Ni bilayer tips versus unmagnetized single layer Fe tips that the image contrast shows domains versus domain walls, respectively. C1 JET PROP LAB,PASADENA,CA 91109. RP WADAS, A (reprint author), NATL INST STAND & TECHNOL,BOULDER,CO 80303, USA. NR 11 TC 15 Z9 15 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 28 PY 1994 VL 64 IS 9 BP 1156 EP 1158 DI 10.1063/1.110837 PG 3 WC Physics, Applied SC Physics GA MZ337 UT WOS:A1994MZ33700034 ER PT J AU SOH, WY AF SOH, WY TI NUMERICAL-SIMULATION OF FREE SHEAR FLOWS AND FAR-FIELD SOUND PRESSURE DIRECTIVITY SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE PADE COMPACT SCHEME; DISPERSION RELATION PRESERVING SCHEME; FREE SHEAR FLOW; LARGE VORTICAL STRUCTURE; ACOUSTIC ANALOGY ID MIXING LAYERS; BOUNDARY-CONDITIONS; HYPERBOLIC SYSTEMS AB An implicit spatial differencing technique with fourth-order accuracy has been developed based on the Pade compact scheme. A dispersion-relation-preserving concept has been incorporated into the numerical scheme. Two-dimensional Euler computation of a spatially developing free shear flow with and without external excitation has been performed to demonstrate the capability of the numerical scheme developed. Results are in good agreement with theory and experimental observation regarding the growth rate of the fluctuating velocity, the convective velocity and the vortex-pairing process. The far-field sound pressure generated by the computed shear flow solution using Lighthill's acoustic analogy shows a strong directivity with a zone of silence at the flow angle. RP SOH, WY (reprint author), NASA,LEWIS RES CTR GRP,SVERDRUP TECHNOL INC,BROOKPARK,OH 44142, USA. NR 18 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD FEB 28 PY 1994 VL 18 IS 4 BP 337 EP 359 DI 10.1002/fld.1650180403 PG 23 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA MW960 UT WOS:A1994MW96000001 ER PT J AU HOLT, RG GAITAN, DF ATCHLEY, AA HOLZFUSS, J AF HOLT, RG GAITAN, DF ATCHLEY, AA HOLZFUSS, J TI CHAOTIC SONOLUMINESCENCE SO PHYSICAL REVIEW LETTERS LA English DT Article ID SYNCHRONOUS PICOSECOND SONOLUMINESCENCE; BELOUSOV-ZHABOTINSKII REACTION; BUBBLE DYNAMICS; TIME-SERIES; CAVITATION; OSCILLATIONS; GEOMETRY AB Sonoluminescence (SL) is generated from single, stably oscillating bubbles in a stationary, time-periodic acoustic field. By measuring the time delay between flashes, the dynamics of the phenomenon has been investigated. While other researchers have concentrated on the remarkable periodic stability of the system, present results indicate that, for small variations in the governing parameters, period doubling, chaos, and quasiperiodicity can occur. The implications of the complex temporal behavior for the problem of determining the mechanism(s) for production of SL are discussed. C1 USN,POSTGRAD SCH,DEPT PHYS,MONTEREY,CA 93943. TH DARMSTADT,INST ANGEW PHYS,D-64289 DARMSTADT,GERMANY. RP HOLT, RG (reprint author), JET PROP LAB,MS 183-401,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Holt, Ray/G-5677-2010; GAITAN, DARIO/N-2727-2016 OI GAITAN, DARIO/0000-0002-2139-8535 NR 35 TC 53 Z9 55 U1 2 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 28 PY 1994 VL 72 IS 9 BP 1376 EP 1379 DI 10.1103/PhysRevLett.72.1376 PG 4 WC Physics, Multidisciplinary SC Physics GA MZ286 UT WOS:A1994MZ28600019 ER PT J AU BOUGHER, SW BORUCKI, WJ AF BOUGHER, SW BORUCKI, WJ TI VENUS O2 VISIBLE AND IR NIGHTGLOW - IMPLICATIONS FOR LOWER THERMOSPHERE DYNAMICS AND CHEMISTRY SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID NIGHTTIME HYDROGEN BULGE; GENERAL-CIRCULATION; COUPLED DYNAMICS; SOLAR CYCLE-21; MESOSPHERE; AIRGLOW; OXYGEN; MODEL; PHOTOCHEMISTRY; TEMPERATURE AB The National Center tor Atmospheric Research thermospheric general circulation model for the Venus thermosphere is modified to examine two observed night airglow features, both of which serve as sensitive tracers of the thermospheric circulation. New O2 nightglow data from the Pioneer Venus Orbiter (PVO) star tracker (O2 Herzberg II at 400-800 nm) and ground-based telescopes (O2 IR at 1.27 mum) (Allen et al., 1992) yield additional model constraints for estimating Venus winds over 100-130 km. Atomic oxygen, produced by dayside CO2. photolysis peaking near 110 km, and transported to the nightside by the global wind system, is partially destroyed through three-body recombination. yielding the O2 Herzberg II visible nightglow. This emission is very sensitive to horizontal winds at altitudes between 100 and 130 km. Other trace species catalytic reactions also contribute to the production of the very strong nightside infrared (1.27 mum) emission. This paper examines the dynamical and chemical implications of these new data using the Venus thermospheric general circulation model (VTGCM) as an analysis tool. Three-dimensional calculations are presented for both solar maximum and solar medium conditions, corresponding to early PVO (1979-1981) and PVO entry (mid-1992) time periods. Very distinct periods are identified in which zonal winds are alternately weak and strong in the Venus lower thermosphere. VTGCM sensitivity studies are conducted to assess the impacts of potential changes in thermospheric zonal and day-to-night winds, and eddy diffusion on the corresponding nightglow intensities. It appears that cyclostrophic balance extends above 80 km periodically, owing to a reversal of the upper mesosphere latitudinal temperature gradient, and thereby producing strong zonal winds and correspondingly modified O2 nightglow distributions that are observed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BOUGHER, SW (reprint author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA. RI Bougher, Stephen/C-1913-2013 OI Bougher, Stephen/0000-0002-4178-2729 NR 51 TC 53 Z9 53 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 25 PY 1994 VL 99 IS E2 BP 3759 EP 3776 DI 10.1029/93JE03431 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA MZ253 UT WOS:A1994MZ25300003 ER PT J AU WILSON, MA POHORILLE, A AF WILSON, MA POHORILLE, A TI MOLECULAR-DYNAMICS OF A WATER-LIPID BILAYER INTERFACE SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID LIQUID-VAPOR INTERFACE; INTERMOLECULAR POTENTIAL FUNCTIONS; MONTE-CARLO SIMULATIONS; DIPOLE-MOMENTS; BIOLOGICAL-MEMBRANES; NEUTRON-DIFFRACTION; MODEL MEMBRANES; CHAIN MOLECULES; X-RAY; MONOLAYERS AB We present results of molecular dynamics simulations of a glycerol 1-monooleate bilayer in water. The total length of analyzed trajectories is 5 ns. The calculated width of the bilayer agrees wi:ll with the experimentally measured value. The interior of the membrane is in a highly disordered fluid state. Atomic density profiles, orientational and conformational distribution functions, and order parameters indicate that disorder increases toward the center of the bilayer. Analysis of out-of-plane thermal fluctuations of the bilayer surfaces occurring at the time scale of the present calculations reveals that the distribution of modes agrees with predictions of the capillary wave model. Fluctuations of both bilayer surfaces are uncorrelated, yielding Gaussian distribution of instantaneous widths of the membrane. Fluctuations of the width produce transient thinning defects in the bilayer which occasionally span almost half of the membrane. The leading mechanism of these fluctuations is the orientational and conformational motion of head groups rather than vertical motion of the whole molecules. Water considerably penetrates the head group region of the bilayer but not its hydrocarbon core. The total net excess dipole moment of the interfacial water points toward the aqueous phase, but the water polarization profile is non-monotonic. Both water and head groups significantly contribute to the surface potential across the interface. The calculated sign of the surface potential is in agreement with that from experimental measurements, but the value is markedly overestimated. The structural and electrical properties of the water-bilayer system are discussed in relation to membrane functions, in particular transport of ions and nonelectrolytes across membranes. C1 UNIV CALIF SAN FRANCISCO, DEPT PHARMACEUT CHEM, SAN FRANCISCO, CA 94143 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. FU NCI NIH HHS [NCA 2-604] NR 80 TC 84 Z9 84 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 23 PY 1994 VL 116 IS 4 BP 1490 EP 1501 DI 10.1021/ja00083a038 PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA MZ287 UT WOS:A1994MZ28700038 PM 11543595 ER PT J AU STOAKLEY, DM STCLAIR, AK CROALL, CI AF STOAKLEY, DM STCLAIR, AK CROALL, CI TI LOW DIELECTRIC, FLUORINATED POLYIMIDE COPOLYMERS SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article AB Copolymers of fluorinated polyimides and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) have been prepared as films and composite laminates. The addition of BPDA was used as a means to achieve insolubility, making the polymers suitable as aircraft matrix resins. Glass transition temperatures, thermooxidative stabilities, and tensile strengths were increased with increasing BPDA content in the copolymers. Although the addition of BPDA did increase the UV cutoff and decrease the percent transmission slightly, the optical transparency of the polymers was still excellent. Dielectric constants of the copolyimide films ranged from 2.6 to 2.9. Astroquartz II laminates made with these resins had dielectric constants of 3.3-3.4. Flexural strengths on unidirectional specimens were in the 1.24-1.41 GPa range and flexural moduli were 41 GPa. (C) 1994 John Wiley & Sons, Inc. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. NR 4 TC 18 Z9 18 U1 1 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD FEB 22 PY 1994 VL 51 IS 8 BP 1479 EP 1483 DI 10.1002/app.1994.070510815 PG 5 WC Polymer Science SC Polymer Science GA MR999 UT WOS:A1994MR99900015 ER PT J AU SATHYENDRANATH, S HOGE, FE PLATT, T SWIFT, RN AF SATHYENDRANATH, S HOGE, FE PLATT, T SWIFT, RN TI DETECTION OF PHYTOPLANKTON PIGMENTS FROM OCEAN COLOR - IMPROVED ALGORITHMS SO APPLIED OPTICS LA English DT Article ID ATLANTIC BIGHT; CHLOROPHYLL; SATELLITE; WATER; DINOFLAGELLATE; REFLECTANCE; MODEL AB Passive ocean-color data at 32 wavelengths in the visible domain and laser-induced fluorescence line heights of chlorophyll and phycoerythrin, measured simultaneously from an aircraft in the New York Bight area, are used to examine the problem of developing algorithms for pigment retrieval from ocean-color data that would be capable of distinguishing between chlorophyll and phycoerythrin. Using factor analysis, it is shown that it is indeed possible to develop such algorithms. Furthermore, the wavelengths used in the algorithms can be reduced from 32 to 6 (similar to the SeaWiFS channels) without much loss in information. These multiwavelength algorithms yield significantly higher correlation coefficients for chlorophyll compared with the conventional blue-green ratio used for retrieval of this pigment. The Coastal Zone Color Scanner wavelengths appear to be inadequate for quantitative retrieval of the phycoerythrin signal. C1 NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA 23337 USA. EG&G, WASHINGTON ANALYT SERV CTR, POCOMOKE CITY, MD 21851 USA. DALHOUSIE UNIV, DEPT OCEANOG, HALIFAX B3H 4J1, NS, CANADA. RP SATHYENDRANATH, S (reprint author), FISHERIES & OCEANS CANADA, BEDFORD INST OCEANOG, DIV BIOL OCEANOG, BOX 1006, DARTMOUTH B2Y 4A2, NS, CANADA. NR 28 TC 50 Z9 54 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 20 PY 1994 VL 33 IS 6 BP 1081 EP 1089 PG 9 WC Optics SC Optics GA NA381 UT WOS:A1994NA38100031 PM 20862120 ER PT J AU WEBB, JR SHRADER, CR BALONEK, TJ CRENSHAW, DM KAZANAS, D CLEMENTS, S SMITH, AG NAIR, AD LEACOCK, RJ GOMBOLA, PP SADUN, A MILLER, HR ROBSON, I FUJIMOTO, R MAKINO, F KII, T ALLER, H ALLER, M HUGHES, P VALTAOJA, E TERASRANTA, H SALONEN, E TORNIKOSKI, M CHISM, W AF WEBB, JR SHRADER, CR BALONEK, TJ CRENSHAW, DM KAZANAS, D CLEMENTS, S SMITH, AG NAIR, AD LEACOCK, RJ GOMBOLA, PP SADUN, A MILLER, HR ROBSON, I FUJIMOTO, R MAKINO, F KII, T ALLER, H ALLER, M HUGHES, P VALTAOJA, E TERASRANTA, H SALONEN, E TORNIKOSKI, M CHISM, W TI THE MULTIFREQUENCY SPECTRAL EVOLUTION OF BLAZAR 3C 345 DURING THE 1991 OUTBURST SO ASTROPHYSICAL JOURNAL LA English DT Article DE QUASARS, INDIVIDUAL (3C 345); RADIO CONTINUUM, GALAXIES; ULTRAVIOLET, GALAXIES; X-RAYS, GALAXIES ID EXTRAGALACTIC SOURCES; X-RAY; RADIO; FLARE; OBJECTS; MODELS AB The blazar 3C 345 underwent a 2.5 mag optical outburst between 1990 November and 1991 May. We have obtained 10 nearly simultaneous multifrequency spectra during the course of the outburst in order to study the multifrequency spectral variations of 3C 345 as a function of time. Although our observations were not sampled frequently enough to completely resolve the variations in every frequency band, the general rise and decline of the outburst were seen in the UV through radio with differing rise times. Simulations of an electron distribution injected into a tangled magnetic field show a relationship between frequency and characteristic timescale that was also observed in the radio variations of 3C 345. The two X-ray observations made during the monitoring period showed no evidence of variability. The multifrequency spectrum was modeled with two major components: a relativistic jet and a relativistic thermal accretion disk. Models calculated for each spectrum indicate that the outburst can be explained in terms of these models by varying the high-energy cutoff of the injected electron distribution in the jet model, while also varying the mass accretion rate in the disk model. There is marginal evidence that the inferred accretion rate varies with the jet luminosity. C1 UKIRT,HILO,HI 96720. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. METSAHOVI RADIO RES STN,SF-02540 KYLMALA,FINLAND. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. COLGATE UNIV,DEPT PHYS & ASTRON,HAMILTON,NY 13346. UNIV FLORIDA,DEPT ASTRON,GAINESVILLE,FL 32611. AGNES SCOTT COLL,BRADLEY OBSERV,DECATUR,GA 30030. GEORGIA STATE UNIV,DEPT PHYS,ATLANTA,GA 30303. UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. RP WEBB, JR (reprint author), FLORIDA INT UNIV,DEPT PHYS,MIAMI,FL 33199, USA. NR 29 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 570 EP 585 DI 10.1086/173750 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600013 ER PT J AU WALLYN, P DUROUCHOUX, P CHAPUIS, C LEVENTHAL, M AF WALLYN, P DUROUCHOUX, P CHAPUIS, C LEVENTHAL, M TI THE ANNIHILATION OF POSITRONS IN THE COLD PHASE OF THE INTERSTELLAR-MEDIUM REVISITED SO ASTROPHYSICAL JOURNAL LA English DT Article DE ELEMENTARY PARTICLES; ISM, ATOMS; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES ID DENSITY GALACTIC ENVIRONMENT; SECONDARY ELECTRONS; ENERGY-DISTRIBUTION; ATOMIC-HYDROGEN; INTERMEDIATE ENERGIES; INELASTIC-SCATTERING; NEUTRAL-HYDROGEN; MOLECULAR CLOUD; CROSS-SECTIONS; RADIATION AB The positron cross sections in H and H2 media are reevaluated, taking into account new experimental results. Using a Monte Carlo simulation, we find a positronium fraction before thermalization of 0.90 for H2, in good agreement with the previous experimental result given by Brown et al. (1986). For H we obtain an upper limit of 0.98. We study the behavior of the charge exchange annihilation in a cold phase (molecular cloud). We calculate formula for the slowing-down time t, before annihilation lasting DELTAt, via charge exchange, of a positron beam with a given energy for different medium densities and initial energies. An upper limit of 0.7 MeV for the initial energy of the positrons, annihilating in the molecular cloud GO.86 - 0.08 near the gamma ray source IE 1740 - 2942, is deduced. Our scenario also explains the lack of detection of the recombination lines from positronium and gives new time constraints on their possible observation. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS,GREENBELT,MD 20771. RP WALLYN, P (reprint author), CENS,DAPNIA,SERV ASTROPHYS,F-91191 GIF SUR YVETTE,FRANCE. NR 64 TC 15 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 610 EP 615 DI 10.1086/173753 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600016 ER PT J AU STAHLER, SW AF STAHLER, SW TI THE KINEMATICS OF MOLECULAR OUTFLOWS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, JETS AND OUTFLOWS; ISM, KINEMATICS AND DYNAMICS; STARS, FORMATION ID CO; CLOUD; L1551 AB If molecular outflows represent turbulent material entrained by a central jet, then the surfaces of constant velocity should spread outward from the jet axis. Using the results of CO observations, I propose an empirical velocity distribution of this character. Outflows with this distribution display the well-documented ''acceleration'' phenomenon, i.e., the increase in terminal velocity away from the driving star. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP STAHLER, SW (reprint author), UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. NR 23 TC 96 Z9 96 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 616 EP 620 DI 10.1086/173754 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600017 ER PT J AU HAKKILA, J MEEGAN, CA PENDLETON, GN FISHMAN, GJ WILSON, RB PACIESAS, WS BROCK, MN HORACK, JM AF HAKKILA, J MEEGAN, CA PENDLETON, GN FISHMAN, GJ WILSON, RB PACIESAS, WS BROCK, MN HORACK, JM TI CONSTRAINTS ON GALACTIC DISTRIBUTIONS OF GAMMA-RAY BURST SOURCES FROM BATSE OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS ID NEUTRON-STARS; ORIGIN; HALO; GALAXY AB The paradigm that gamma-ray bursts originate from Galactic sources is studied in detail using the angular and intensity distributions observed by the Burst and Transient Source Experiment (BATSE) on NASA's Compton Gamma Ray Observatory (CGRO). Monte Carlo models of gamma-ray burst spatial distributions and luminosity functions are used to simulate bursts, which are then folded through mathematical models of BATSE selection effects. The observed and computed angular intensity distributions are analyzed using modifications of standard statistical homogeneity and isotropy studies. Analysis of the BATSE angular and intensity distributions greatly constrains the origins and luminosities of burst sources. In particular, it appears that no single population of sources confined to a Galactic disk, halo, or localized spiral arm satisfactorily explains BATSE observations and that effects of the burst luminosity function are secondary when considering such models. One family of models that still satisfies BATSE observations comprises sources located in an extended spherical Galactic corona. Coronal models are limited to small ranges of burst luminosity and core radius, and the allowed parameter space for such models shrinks with each new burst BATSE observes. Multiple-population models of bursts are found to work only if (1) the primary population accounts for the general isotropy and inhomogeneity seen in the BATSE observations and (2) secondary populations either have characteristics similar to the primary population or contain numbers -that are small relative to the primary population. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. RP HAKKILA, J (reprint author), MANKATO STATE UNIV,DEPT MATH ASTRON & STAT,MANKATO,MN 56002, USA. RI Horack, John/J-6670-2016 NR 79 TC 63 Z9 63 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 659 EP 670 DI 10.1086/173759 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600022 ER PT J AU CHRISTIAN, DJ WHITE, NE SWANK, JH AF CHRISTIAN, DJ WHITE, NE SWANK, JH TI ACCRETION DISK CORONA LINE EMISSION FROM X0614+091 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; BINARIES, CLOSE; STARS, INDIVIDUAL (X0614+091); STARS, CORONAE; X-RAYS; STARS ID X-RAY SOURCES; CROSS-SECTIONS; SCORPIUS X-1; SPECTROMETER; BINARIES; SPECTRA; MODELS; BURST AB The low-mass X-ray binary X0614 + 091 was observed on 3 days in 1979 with the Einstein Observatory solid state spectrometer and the monitor proportional counter. During the observation with the highest measured flux, corresponding to an X-ray luminosity of 8 x 10(36) ergs s-1 (in the 0.5-20 keV band for an assumed distance of 5 kpc), significant low-energy emission was detected, centered at 0.77 keV, possibly due to line emission for O VII-O VIII and Fe XVII-Fe XIX. The other observations, which were at fluxes lower by a factor of 2, are consistent with the presence of the emission feature. The equivalent width of the feature, 37 +/- 6 eV, is of the same order as equivalent widths previously reported for more luminous low-mass X-ray binaries using grating spectrometer data. The soft X-ray lines could be emitted by gas expected to arise in an accretion disk corona excited by the central source. But to explain the observed feature, most of the corona needs to contribute, or other sources of emission are required. C1 UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. RP CHRISTIAN, DJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 666,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012; Swank, Jean/F-2693-2012 OI White, Nicholas/0000-0003-3853-3462; NR 36 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 791 EP 798 DI 10.1086/173771 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600034 ER PT J AU HAUSCHILDT, PH STARRFIELD, S AUSTIN, S WAGNER, RM SHORE, SN SONNEBORN, G AF HAUSCHILDT, PH STARRFIELD, S AUSTIN, S WAGNER, RM SHORE, SN SONNEBORN, G TI NON-LTE MODEL ATMOSPHERE ANALYSIS OF NOVA CYGNI 1992 SO ASTROPHYSICAL JOURNAL LA English DT Article DE NOVAE, CATACLYSMIC VARIABLES; STARS, ABUNDANCES; STARS, ATMOSPHERES; STARS, INDIVIDUAL (NOVA CYGNI 1992); ULTRAVIOLET, STARS ID SPECIAL RELATIVISTIC EQUATION; RADIATIVE-TRANSFER; SHELLS; WINDS AB We use spherically symmetric, non-LTE, line-blanketed, expanding model atmospheres to analyze the IUE and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is best reproduced by a model atmosphere with a steep density gradient and homologous expansion, whereas the IUE and optical spectra obtained on February 24 show an extended, optically thick, wind structure. Therefore, we distinguish two phases of the early evolution of the nova photosphere: the initial, rapid, ''fireball'' phase and the subsequent, much longer, optically thick ''wind'' phase. The importance of line-blanketing in nova spectra is demonstrated. Our preliminary abundance analysis implies that hydrogen is depleted in the ejecta, corresponding to abundance enhancements of Fe by a factor of almost-equal-to 2 and of CNO by more than a factor of 10 when compared to solar abundances. The synthetic spectra reproduce both the observed pseudo-continua as well as most of the observed features from the UV to the optical spectral range and demonstrate the importance of obtaining nearly simultaneous UV and optical spectra for performing accurate analyses of expanding stellar atmospheres (for both novae and supernovae). C1 OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. INDIANA UNIV S BEND,DEPT PHYS & ASTRON,S BEND,IN 46634. NASA,GODDARD SPACE FLIGHT CTR,LASP,GREENBELT,MD 20771. RP HAUSCHILDT, PH (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287, USA. RI Sonneborn, George/D-5255-2012 NR 19 TC 54 Z9 54 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 831 EP 844 DI 10.1086/173775 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600038 ER PT J AU TOMLEY, L STEIMANCAMERON, TY CASSEN, P AF TOMLEY, L STEIMANCAMERON, TY CASSEN, P TI FURTHER-STUDIES OF GRAVITATIONALLY UNSTABLE PROTOSTELLAR DISKS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SOLAR SYSTEM, FORMATION; STARS, CIRCUMSTELLAR SHELLS; STARS, FORMATION ID NUMERICAL EXPERIMENTS; ACCRETION DISK; EVOLUTION; STABILITY; COLLAPSE; CLOUDS AB Models of the solar nebula reveal that it might have been gravitationally unstable, both early and later in its evolution. Such instabilities produce density waves and associated gravitational torques, which are potent agents of angular momentum transport. In previous work, we conducted a series of numerical simulations designed to quantify the effects of gravitational instabilities in a generalizable way (Tomley, Cassen, & Steiman-Cameron 1991). Here we present a second series of simulations in which we examine disks of greater size, increased star/disk mass ratio, and flatter surface density distribution than those in our initial study. The purpose is to represent disks at a later stage of evolution than those already studied, to test the quantitative relations derived in our earlier work and to explore the effects of mass ratio on the results. The new results indicate that the tendencies for unstable, uncooled disks to heat to stability and for dynamical evolution rates to be proportional to cooling rates are general characteristics of the behavior of gravitationally unstable disks. Nevertheless, there are quantitative, and (for strong cooling) even qualitative differences that are revealed in the new simulations, particularly with regard to the cooling rates at which clumping tends to occur. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP TOMLEY, L (reprint author), SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95192, USA. NR 16 TC 46 Z9 46 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP 850 EP 861 DI 10.1086/173777 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ636 UT WOS:A1994MZ63600040 ER PT J AU CHENG, ES COTTINGHAM, DA FIXSEN, DJ INMAN, CA KOWITT, MS MEYER, SS PAGE, LA PUCHALLA, JL SILVERBERG, RF AF CHENG, ES COTTINGHAM, DA FIXSEN, DJ INMAN, CA KOWITT, MS MEYER, SS PAGE, LA PUCHALLA, JL SILVERBERG, RF TI A MEASUREMENT OF THE MEDIUM-SCALE ANISOTROPY IN THE COSMIC MICROWAVE BACKGROUND-RADIATION SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, COSMIC MICROWAVE BACKGROUND; COSMOLOGY, OBSERVATIONS ID MILLIMETER; SUBMILLIMETER; JUPITER AB Observations from the first flight of the Medium Scale Anisotropy Measurement (MSAM) are analyzed to place limits on Gaussian fluctuations in the cosmic microwave background radiation (CMBR). This instrument chops a 30' beam in a three-position pattern with a throw of +/-40'; the resulting data is analyzed in statistically independent single- and double-difference data sets. We observe in four spectral channels at 5.6, 9.0, 16.5, and 22.5 cm-1, allowing the separation of interstellar dust emission from CMBR fluctuations. The dust component is correlated with the IRAS 100 mum map. The CMBR component has two regions where the signature of an unresolved source is seen. Rejecting these two source regions, we obtain a detection of fluctuations which match CMBR in our spectral bands of 0.6 x 10(-5) < DELTAT/T < 2.2 x 10(-5) (90% CL interval) for total rms Gaussian fluctuations with correlation angle 0.5-degrees, using the single-difference demodulation. For the double difference demodulation, the result is 1.1 x 10(-5) < DELTAT/T < 3.1 x 10(-5) (90% CL interval) at a correlation angle of 0.3-degrees. C1 NASA,GODDARD SPACE FLIGHT CTR,GLOBAL SCI & TECHNOL INC,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,GREENBELT,MD 20771. MIT,CAMBRIDGE,MA 02139. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. RP CHENG, ES (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 6850,GREENBELT,MD 20771, USA. NR 19 TC 87 Z9 87 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L37 EP L40 DI 10.1086/187206 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700002 ER PT J AU KOUVELIOTOU, C PREECE, R BHAT, N FISHMAN, GJ MEEGAN, CA HORACK, JM BRIGGS, MS PACIESAS, WS PENDLETON, GN BAND, D MATTESON, J PALMER, D TEEGARDEN, B NORRIS, JP AF KOUVELIOTOU, C PREECE, R BHAT, N FISHMAN, GJ MEEGAN, CA HORACK, JM BRIGGS, MS PACIESAS, WS PENDLETON, GN BAND, D MATTESON, J PALMER, D TEEGARDEN, B NORRIS, JP TI BATSE OBSERVATIONS OF THE VERY INTENSE GAMMA-RAY BURST GRB-930131 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS; BURSTS AB BATSE observed its most intense gamma-ray burst on 1993 January 31. The event reached count rates greater than or similar to 2 x 10(6) counts s-1 with most of the flux emitted in an extremely short (less than or similar 0.1 s) interval followed by a long tail, lasting about 50 s. Most of this initial pulse was recorded by our instrument with unique, very high temporal resolution (I ms). We were thus able to show large changes in spectral hardness on 2 ms timescales throughout this initial complex. Photons as low as 25 keV and extending up to >4 MeV in energy were recorded by BATSE during this first interval. The burst spectrum is best fitted by a broken power law with a break energy of 170 +/- 27 keV. The low-energy spectral index is -1.30 +/- 0.05, while a softer spectral index of -1.9 fits the spectrum between 170 keV and 2 MeV. Our data provide the only low-energy spectrum for this event; the combination of our spectrum with the one reported for GRB 930131 by the EGRET group extends the total energy spectrum of a GRB for the first time over five decades, up to the GeV range. C1 UNIV SPACE RES ASSOC,HUNTSVILLE,AL. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP KOUVELIOTOU, C (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. RI Horack, John/J-6670-2016 NR 4 TC 26 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L59 EP L62 DI 10.1086/187212 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700008 ER PT J AU RYAN, J BENNETT, K COLLMAR, W CONNORS, A FISHMAN, GJ GREINER, J HANLON, LO HERMSEN, W KIPPEN, RM KOUVELIOTOU, C KUIPER, L LICHTI, G MACRI, J MATTOX, J MCCONNELL, M MCNAMARA, B MEEGAN, C SCHONFELDER, V VANDIJK, R VARENDORFF, M WEBBER, WR WINKLER, C AF RYAN, J BENNETT, K COLLMAR, W CONNORS, A FISHMAN, GJ GREINER, J HANLON, LO HERMSEN, W KIPPEN, RM KOUVELIOTOU, C KUIPER, L LICHTI, G MACRI, J MATTOX, J MCCONNELL, M MCNAMARA, B MEEGAN, C SCHONFELDER, V VANDIJK, R VARENDORFF, M WEBBER, WR WINKLER, C TI COMPTEL MEASUREMENTS OF THE GAMMA-RAY BURST GRB-930131 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS AB On 1993 January 31 at 1857:12 UT, the Imaging Compton Telescope COMPTEL onboard the Compton Gamma Ray Observatory (CGRO) detected the cosmic gamma-ray burst GRB 930131. COMPTEL's MeV imaging capability was employed to locate the source to better than 2-degrees (1 sigma error radius) within 7 hr of the event, initiating a world-wide search for an optical and radio counterpart. The maximum likelihood position of the burst from the COMPTEL data is alpha2000 = 12h18m, delta2000 = -9-degrees-42', consistent with independent CGRO-BATSE and EGRET locations as well as with the triangulation annulus constructed using BATSE and Ulysses timing data. The combined COMPTEL and EGRET burst data yield a better estimate of the burst location: alpha2000 = 12h12m and delta2000 = -10-degrees-21', with a 1 sigma error radius of 32'. In COMPTEL's energy range, this burst was short, consisting of two separate spikes occurring within a approximately 1 s interval with a low intensity tail for approximately 1 s after the second spike. No statistically significant flux is present for a 30 s period after the main part of the burst. This is consistent with the EGRET data. The COMPTEL telescope events indicate a hard, power-law emission extending to beyond 10 MeV with a spectral index of -1.8 +/- 0.4. The rapid fluctuations and high intensities of the gamma-ray flux > 10 MeV place the burst object no farther than 250 pc if the burst emission is not beamed. C1 ESTEC,DIV ASTROPHYS,NOORDWIJK,NETHERLANDS. MAX PLANCK INST EXTRATERR PHYS,GARCHING,GERMANY. SRON,LEIDEN,2300 RA LEIDEN,NETHERLANDS. COMP SCI CORP,GREENBLET,MD 20771. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP RYAN, J (reprint author), UNIV NEW HAMPSHIRE,CTR SPACE SCI,DURHAM,NH 03824, USA. NR 19 TC 27 Z9 29 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L67 EP L70 DI 10.1086/187214 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700010 ER PT J AU SCHAEFER, BE BARTHELMY, SD PALMER, DM CLINE, TL HURLEY, KC SOMMER, M BOER, M NIEL, M FISHMAN, GJ KOUVELIOTOU, C MEEGAN, CA COE, MJ ELMEGREEN, BG MCNAMARA, BJ HARRISON, T OWENS, A SOLLEE, N STULL, J PALERMITI, M SCHWARTZ, R BROOKS, J VANDERSPEK, R RICKER, GR KRIMM, HA WENZEL, W GREINER, J HUDEC, R NOVAK, M BOROVICKA, J PREDOTA, M BAILYN, CD HANLON, LO BENNETT, K SPOELSTRA, TAT SMETTE, A PEDERSEN, H FLORENTIN, R POLLAS, C STEINLE, H SCHRAMM, KJ IYENGAR, KVK PRABHU, TP AF SCHAEFER, BE BARTHELMY, SD PALMER, DM CLINE, TL HURLEY, KC SOMMER, M BOER, M NIEL, M FISHMAN, GJ KOUVELIOTOU, C MEEGAN, CA COE, MJ ELMEGREEN, BG MCNAMARA, BJ HARRISON, T OWENS, A SOLLEE, N STULL, J PALERMITI, M SCHWARTZ, R BROOKS, J VANDERSPEK, R RICKER, GR KRIMM, HA WENZEL, W GREINER, J HUDEC, R NOVAK, M BOROVICKA, J PREDOTA, M BAILYN, CD HANLON, LO BENNETT, K SPOELSTRA, TAT SMETTE, A PEDERSEN, H FLORENTIN, R POLLAS, C STEINLE, H SCHRAMM, KJ IYENGAR, KVK PRABHU, TP TI RAPID SEARCHES FOR COUNTERPARTS OF GRB-930131 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS ID RAY BURSTER COUNTERPARTS AB A fading counterpart to a gamma-ray burst (GRB) would appear as a point source inside a GRB error region soon after the burst which dims on a timescale from minutes to days. The favorable circumstances of the burst GRB 930131 allowed for an international campaign to search for fading counterparts starting 6.8 hr after the burst. We report observations from many optical sites, two radio telescopes, and archival ROSAT data, including deep Schmidt exposures 35, 44, and 64 hr after the burst. No fading counterparts were detected with our observations. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. UNIV SOUTHAMPTON,SOUTHAMPTON SO9 5NH,HANTS,ENGLAND. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. UNIV LEICESTER,LEICESTER LE1 7RH,ENGLAND. SANTA BARBARA ASTRON GRP,SANTA BARBARA,CA. ALFRED UNIV,ALFRED,NY 14802. MIT,CAMBRIDGE,MA 02139. SONNEBERG OBSERV,W-6400 SONNEBERG,GERMANY. ASTRON INST,CS-25165 ONDREJOV,CZECHOSLOVAKIA. YALE UNIV,DEPT ASTRON,NEW HAVEN,CT 06511. HAMBURG OBSERV,W-2050 HAMBURG 80,GERMANY. UNIV SPACE RES ASSOC,HUNTSVILLE,AL. MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. UPS,CNRS,CTR ETUDE SPATIALE RAYONNEMENTS,F-31029 TOULOUSE,FRANCE. PALERMITI OBSERV,JUPITER,FL 33478. METEOROL STN CHURANOV,CHURANOV,CZECHOSLOVAKIA. ESA,ESTEC,DIV ASTROPHYS,2200 AG NOORDWIJK,NETHERLANDS. NFRA,RADIO OBSERV,7990 AA DWINGELOO,NETHERLANDS. EUROPEAN SO OBSERV,LA SERENA,CHILE. COPENHAGEN UNIV OBSERV,DK-1350 COPENHAGEN K,DENMARK. CERGA,OBSERVA COTE AZUR,OBSERV CALERN,F-06460 ST VALLIER THIEY,FRANCE. INDIAN INST ASTROPHYS,BANGALORE 560034,INDIA. RI Barthelmy, Scott/D-2943-2012; Borovicka, Jiri/F-4257-2014; Hudec, Rene/G-9018-2014 NR 27 TC 26 Z9 26 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L71 EP L74 DI 10.1086/187215 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700011 ER PT J AU SOMMER, M BERTSCH, DL DINGUS, BL FICHTEL, CE FISHMAN, GJ HARDING, AK HARTMAN, RC HUNTER, SD HURLEY, K KANBACH, G KNIFFEN, DA KOUVELIOTOU, C LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL SCHNEID, E SREEKUMAR, P THOMPSON, DJ AF SOMMER, M BERTSCH, DL DINGUS, BL FICHTEL, CE FISHMAN, GJ HARDING, AK HARTMAN, RC HUNTER, SD HURLEY, K KANBACH, G KNIFFEN, DA KOUVELIOTOU, C LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL SCHNEID, E SREEKUMAR, P THOMPSON, DJ TI HIGH-ENERGY GAMMA-RAYS FROM THE INTENSE 1993 JANUARY 31 GAMMA-RAY BURST SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCELERATION OF PARTICLES; GAMMA RAYS, BURSTS; GAMMA RAYS, OBSERVATIONS AB The intense gamma-ray burst of 1993 January 31 was detected by the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Observatory. Sixteen gamma rays above 30 MeV were imaged in the telescope when only 0.04 gamma rays were expected by chance. Two of these gamma rays have energies of approximately 1 GeV, and the five bin spectrum of the 16 events is fitted by a power law of photon spectral index -2.0 +/- 0.4. The high-energy emission extends for at least 25 s. The most probable direction for this burst is determined from the directions of the 16 gamma rays observed by EGRET and also by requiring the position to lie on annulus derived by the Interplanetary Network. C1 UNIV SPACE RES ASSOC,HUNTSVILLE,AL. COMPTON OBSERV SCI SUPPORT CTR,COMP SCI CORP,ASTRON PROGRAMS,GREENBELT,MD. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. HAMPDEN SYDNEY COLL,HAMPDEN SYDNEY,VA 23943. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. STANFORD UNIV,HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. RP SOMMER, M (reprint author), MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; Harding, Alice/D-3160-2012 OI Thompson, David/0000-0001-5217-9135; NR 23 TC 113 Z9 115 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L63 EP L69 DI 10.1086/187213 PN 2 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700009 ER PT J AU STOMPOR, R GORSKI, KM AF STOMPOR, R GORSKI, KM TI COSMIC MICROWAVE BACKGROUND ANISOTROPIES IN COLD DARK-MATTER MODELS WITH COSMOLOGICAL CONSTANT - THE INTERMEDIATE VERSUS LARGE ANGULAR SCALES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND ID RADIATION AB We obtain predictions for cosmic microwave background anisotropies at angular scales near 1-degrees in the context of cold dark matter models with a nonzero cosmological constant, normalized to the COBE-DMR detection. The results are compared to those computed in the matter-dominated models. We show that the coherence length of the CMB anisotropy is almost insensitive to cosmological parameters, and the rms amplitude of the anisotropy increases moderately with decreasing total matter density, while being most sensitive to the baryon abundance. We apply these results in the statistical analysis of the published data from the UCSB South Pole (SP) experiment (Gaier et al. 1992; Schuster et al. 1993). We reject most of the CDM-LAMBDA models at the 95% confidence level when both SP scans are simulated together (although the combined data set renders less stringent limits than the Gaier et al. data alone). However, the Schuster et al. data considered alone, as well as the results of some other recent experiments (MAX, MSAM, Saskatoon), suggest that typical temperature fluctuations on degree scales may be larger than is indicated by the Gaier et al. scan. If so, CDM-LAMBDA models may indeed provide, from the point of view of CMB anisotropies, an acceptable alternative to flat CDM models. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. RP STOMPOR, R (reprint author), LOS ALAMOS NATL LAB,THEORET ASTROPHYS GRP,T-6,MS B288,LOS ALAMOS,NM 87545, USA. NR 16 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1994 VL 422 IS 2 BP L41 EP L44 DI 10.1086/187207 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ637 UT WOS:A1994MZ63700003 ER PT J AU HERMAN, JR LARKO, D AF HERMAN, JR LARKO, D TI LOW OZONE AMOUNTS DURING 1992-1993 FROM NIMBUS 7 AND METEOR 3 TOTAL OZONE MAPPING SPECTROMETERS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DIABATIC CIRCULATION; NORTHERN-HEMISPHERE; STRATOSPHERIC OZONE; TOMS DATA; TRENDS; MODEL; COMPUTATION; LATITUDE; IMPACT; HOLE AB The global distribution of ozone during the October 31, 1978, to May 6, 1993, observing lifetime of the Nimbus 7 total ozone mapping spectrometer (TOMS) is described, with emphasis on the low ozone amounts observed during 1992 and 1993. Ozone amount time series are extended beyond May 6, 1993, to the end of July 1993 using preliminary Meteor 3 TOMS data. Time series for zonally averaged ozone amounts show that there has not been a significant shift in the seasonal patterns of ozone maxima and minima caused by the Mount Pinatubo eruption or by the onset of very low ozone values during 1992 and 1993. There has been a relatively slow, nearly linear decrease in the amount of ozone over the entire globe from 1979 to the end of 1991, with rates ranging from no change at the equator to a 4-6% decrease per decade at midlatitudes and a 10-12% decrease per decade at higher latitudes. After the eruption of Mount Pinatubo during June 1991, the ozone amount decreased in the equatorial latitudes (10-degrees-S to 10-degrees-N) for about 6 months (-10 Dobson units (DU) between 0-degrees and 10-degrees-S and -3 DU between 0-degrees and 10-degrees-N). During 1992 and continuing into 1993, the rate of ozone decrease deviated from the previously linear trend with the onset of changes that were large in comparison with the historical range of ozone values from 1979 to 1991. The first of the large decreases in ozone amount occurred earlier, in February 1990 to May 1990, at 50-degrees-70-degrees-N. At high northern latitudes, the 1993 decreased ozone amounts were about 12.5% below the envelope of historical values; at midlatitudes they were about 7% lower; and at low latitudes they were about 4% lower. Area-weighted averages in the northern and southern hemispheres show that most of the 1992-1993 ozone losses have occurred in the northern hemisphere. The 1993 global average (70-degrees-S to 70-degrees-N) ozone amount is 3% below the 1979 to 1991 minimum, 5% below the historical envelope in the northern hemisphere, and near the lower boundary of the historical envelope in the southern hemisphere. In the 70-degrees-60-degrees-S latitude band, the ozone losses between 1979 and 1993 have reduced the annual minimum amount to values below those seen in the equatorial regions. C1 HUGHES STX CORP, LANHAM, MD 20706 USA. RP HERMAN, JR (reprint author), NASA, GODDARD SPACE FLIGHT CTR, MAIL CODE 916, GREENBELT, MD 20771 USA. OI Herman, Jay/0000-0002-9146-1632 NR 38 TC 67 Z9 69 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1994 VL 99 IS D2 BP 3483 EP 3496 DI 10.1029/93JD02594 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA MY580 UT WOS:A1994MY58000005 ER PT J AU YUE, GK POOLE, LR WANG, PH CHIOU, EW AF YUE, GK POOLE, LR WANG, PH CHIOU, EW TI STRATOSPHERIC AEROSOL ACIDITY, DENSITY, AND REFRACTIVE-INDEX DEDUCED FROM SAGE-II AND NMC TEMPERATURE DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFURIC-ACID; PINATUBO AEROSOLS; DROPLETS; GROWTH; N2O5 AB Water vapor concentrations obtained by the Stratospheric Aerosol and Gas Experiment II (SAGE II) and collocated temperatures provided by the National Meteorological Center from 1986 to 1990 are used to deduce seasonally and zonally averaged acidity, density, and refractive index of stratospheric aerosols. It is found that the weight percentage of sulfuric acid in the aerosols increases from about 60 just above the tropopause to about 86 at 35 km. The density increases from about 1.55 to 1.85 g cm-3 between the same altitude limits. Some seasonal variations of composition and density are evident at high latitudes. The refractive indices at 1.02, 0.694, and 0.532 mum increase, respectively, from about 1.425, 1.430, and 1.435 just above the tropopause to about 1.445, 1.455, and 1.458 at altitudes above 27 km, depending on the season and latitude. The aerosol properties presented can be used in models to study the effectiveness of heterogeneous chemistry, the mass loading of stratospheric aerosols, and the extinction and backscatter of aerosols at different wavelengths. Computed aerosol surface areas, rate coefficients for the heterogeneous reaction ClONO2 + H2O --> HOCl + HNO3 and aerosol mass concentrations before and after the Pinatubo eruption in June 1991 are shown as sample applications. C1 SCI & TECHNOL CORP, HAMPTON, VA USA. SAIC, HAMPTON, VA USA. RP YUE, GK (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL CODE 475, HAMPTON, VA 23681 USA. NR 27 TC 49 Z9 50 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1994 VL 99 IS D2 BP 3727 EP 3738 DI 10.1029/93JD02989 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA MY580 UT WOS:A1994MY58000025 ER PT J AU LAMOURI, A KRAINSKY, IL AF LAMOURI, A KRAINSKY, IL TI ANGLE-RESOLVED INVERSE-PHOTOEMISSION FROM W(001) SO SURFACE SCIENCE LA English DT Article ID UNOCCUPIED SURFACE-STATES; TUNGSTEN 001 SURFACE; ELECTRONIC-STRUCTURE; PHASE-TRANSITIONS; W 001; RECONSTRUCTION; HYDROGEN; MO(001); W(100); CHEMISORPTION AB Angle-resolved inverse photoelectron spectroscopy (IPS) in the isochromat mode was used to map the unoccupied energy levels of the W(001) surface. Data were collected at room temperature along the GAMMASIGMAMBAR symmetry line of the surface Brillouin zone (SBZ) of the 1 X 1 structure. States observed near 0.5, 3.0 and 4.5 eV above the Fermi level (EF) showed strong sensitivity to surface contamination and were therefore assigned to surface states and/or resonances. These states showed little or no dispersion as expected for states with significant d character. The dispersion of the state near 0.5 eV above E(F) is in good agreement with recent band structure calculations. The implications of our results on the driving force leading to the reconstruction of the W(001) surface are discussed. C1 NASA,LERC,21000 BROOKPK RD,CLEVELAND,OH 44135. NR 31 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 20 PY 1994 VL 303 IS 3 BP 341 EP 346 DI 10.1016/0039-6028(94)90781-1 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA NA606 UT WOS:A1994NA60600010 ER PT J AU HUDSON, RS OSTRO, SJ AF HUDSON, RS OSTRO, SJ TI SHAPE OF ASTEROID 4769 CASTALIA (1989 PB) FROM INVERSION OF RADAR IMAGES SO SCIENCE LA English DT Article AB The inversion of previously reported, delay-Doppler images of Castalia yields a 167-parameter, three-dimensional shape model that is bifurcated into two distinct, irregular, kilometer-sized lobes. The crevice that separates the lobes has an average depth of between 100 and 150 meters and is oriented roughly perpendicular to the asteroid's longest dimension. The constrained least-squares reconstruction method introduced here can be used to determine the shape, spin vector, and radar-scattering properties of any asteroid or comet for which delay-Doppler images provide sufficient signal-to-noise ratio, orientational coverage, and spatial resolution. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP HUDSON, RS (reprint author), WASHINGTON STATE UNIV,SCH ELECT ENGN & COMP SCI,PULLMAN,WA 99164, USA. NR 7 TC 105 Z9 106 U1 2 U2 4 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 18 PY 1994 VL 263 IS 5149 BP 940 EP 943 DI 10.1126/science.263.5149.940 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MX165 UT WOS:A1994MX16500026 PM 17758634 ER PT J AU GOTSIS, PK AF GOTSIS, PK TI STRUCTURAL OPTIMIZATION OF SHELL STRUCTURES SO COMPUTERS & STRUCTURES LA English DT Article AB The objective of the present work was the structural optimization of thin shell structures that are subjected to stress and displacement constraints. In order to accomplish this, the structural optimization computer program DESAP1 was modified and improved. In the static analysis part of the DESAP1 computer program the torsional spring elements, which are used to analyze thin, shallow shell structures, were eliminated by modifying the membrane stiffness matrix of the triangular elements in the local coordinate system and adding a fictitious rotational stiffness matrix. This simplified the DESAP1 program input, improved the accuracy of the analysis, and saved computation time. In the optimization part of the DESAP1 program the stress ratio formula, which redesigns the thickness of each finite element of the structure, was solved by an analytical method. This scheme replaced the iterative solution that was previously used in the DESAP1 program, thus increasing the accuracy and speed of the redesign. The modified program was used to design a thin, cylindrical shell structure with optimum weight, and the results are reported in this paper. RP GOTSIS, PK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 21 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD FEB 17 PY 1994 VL 50 IS 4 BP 499 EP 507 DI 10.1016/0045-7949(94)90020-5 PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA NJ838 UT WOS:A1994NJ83800006 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI HEAT OF FORMATION OF CH2OH SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; ELECTRON CORRELATION; ENERGIES; MOLECULES; KINETICS; METHANOL; ATOMS; CH3O AB The heat of formation of CH2OH at 298 K is determined to be -15.2 +/- 3.5 kJ/mol using high levels of theory. This is in good agreement with some recent experimental determinations. The assignment of the error bars is discussed in detail and compared with that assigned in previous theoretical calculations. The largest uncertainty arises from the calculation of the zero-point energy. RP BAUSCHLICHER, CW (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 32 TC 26 Z9 27 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 17 PY 1994 VL 98 IS 7 BP 1826 EP 1829 DI 10.1021/j100058a017 PG 4 WC Chemistry, Physical SC Chemistry GA MX854 UT WOS:A1994MX85400017 ER PT J AU ZIMMERMANN, HU LEWIN, W PREDEHL, P ASCHENBACH, B FABBIANO, G HASINGER, G LUBIN, L MAGNIER, E VANPARADIJS, J PETRE, R PIETSCH, W TRUMPER, J AF ZIMMERMANN, HU LEWIN, W PREDEHL, P ASCHENBACH, B FABBIANO, G HASINGER, G LUBIN, L MAGNIER, E VANPARADIJS, J PETRE, R PIETSCH, W TRUMPER, J TI DETECTION OF SOFT X-RAYS FROM SUPERNOVA 1993J 6 DAYS AFTER OUTBURST SO NATURE LA English DT Article AB ON 28 March 1993, a new supernova was discovered(1) in the nearby galaxy M81. The proximity of the event (the distance(2) to M81 is only 3.6 Mpc), and the fact that the supernova was detected at an early stage of its outburst(3), makes SN1993J an ideal candidate for the detailed study of the evolution of a supernova in all wavelength regimes. We report here the detection of soft X-ray emissions from SN1993J, six days after the initial discovery, and the subsequent evolution of the X-ray light curve over the next 41 days. The spectral characteristics of the emissions can be readily explained if the X-rays originate in strong shock fronts produced by the rapid expansion of the supernova ejecta into the slow, dense wind of a red supergiant progenitor star(4). The low intrinsic absorption of the earliest emissions requires that any circumstellar material is ionized, probably by the intense radiation of the initial outburst. The decay of the X-ray luminosity with time should provide important constraints on the density profiles of both the circumstellar gas and the outermost layers of the supernova ejecta. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. PRINCETON UNIV OBSERV,PRINCETON,NJ 08544. UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,1098 SJ AMSTERDAM,NETHERLANDS. CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS. GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP ZIMMERMANN, HU (reprint author), MAX PLANCK INST EXTRATERR PHYS,POSTFACH 1603,D-85740 GARCHING,GERMANY. NR 17 TC 59 Z9 59 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 17 PY 1994 VL 367 IS 6464 BP 621 EP 623 DI 10.1038/367621a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MW688 UT WOS:A1994MW68800045 ER PT J AU BILLS, BG DESILVA, SL CURREY, DR EMENGER, RS LILLQUIST, KD DONNELLAN, A WORDEN, B AF BILLS, BG DESILVA, SL CURREY, DR EMENGER, RS LILLQUIST, KD DONNELLAN, A WORDEN, B TI HYDRO-ISOSTATIC DEFLECTION AND TECTONIC TILTING IN THE CENTRAL ANDES - INITIAL RESULTS OF A GPS SURVEY OF LAKE MINCHIN SHORELINES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLATE BENEATH PERU; MANTLE VISCOSITY; NAZCA PLATE; BOLIVIAN ANDES; ICE-SHEET; SUBDUCTION; BONNEVILLE; CONSTRAINTS; ADJUSTMENT; ALTIPLANO AB Sufficiently large lake loads provide a means of probing rheological stratification of the crust and upper mantle. Lake Minchin was the largest of the late Pleistocene pluvial lakes in the central Andes. Prominent shorelines, which formed during temporary still-stands in the climatically driven lake level history, preserve records of lateral variations in subsequent net vertical motions. At its maximum extent the lake was 140 m deep and spanned 400 km N-S and 200 km E-W. The load of surficial water contained in Lake Minchin was sufficient to depress the crust and underlying mantle by 2040 m, depending on the subjacent rheology. Any other differential vertical motions will also be recorded as departures from horizontality of the shorelines. We recently conducted a survey of shoreline elevations of Lake Minchin with the express intent of monitoring the hydro-isostatic deflection and tectonic tilting. Using real-time differential GPS, we measured topographic profiles across suites of shorelines at 15 widely separated locations throughout the basin. Horizontal and vertical accuracies attained are roughly 30 and 70 cm, respectively. Geomorphic evidence suggests that the highest shoreline was occupied only briefly (probably less than 200 years) and radiocarbon dates on gastropod shells found in association with the shore deposits constrain the age to roughly 17 kyr. The basin-wide pattern of elevations of the highest shoreline is composed of two distinct signals: (27 +/- 1) m of hydro-isostatic deflection due to the lake load, and a planar tilt with east and north components of (6.8 +/- 0.4) 10(-5) and (-5.3 +/- 0.3) 10(-5). This Tate of tilting is too high to be plausibly attributed to steady tectonism, and presumably reflects some unresolved combination of tectonism plus the effects of oceanic and lacustrine loads on a laterally heterogeneous substrate. The history of lake level fluctuations is still inadequately known to allow detailed inferences of crust and mantle rheology. However, it is already clear that the effective elastic plate thickness is closer to 40 km than the 60-70 km crustal thickness in the central Andes and the effective viscosity is less than 5 10(20) Pa s. C1 UNIV UTAH,DEPT GEOG,SALT LAKE CITY,UT 84112. INDIANA STATE UNIV,DEPT GEOG & GEOL,TERRE HAUTE,IN 47809. JET PROP LAB,PASADENA,CA 91109. DRAKE UNIV,DEPT GEOG & GEOL,DES MOINES,IA 50311. CALTECH,SEISMOL LAB,PASADENA,CA 91125. RP BILLS, BG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. RI Bills, Bruce/C-1156-2008; de Silva, Shanaka/A-4630-2011 OI de Silva, Shanaka/0000-0002-0310-5516 NR 45 TC 54 Z9 54 U1 2 U2 8 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 FEB 15 PY 1994 VL 21 IS 4 BP 293 EP 296 DI 10.1029/93GL03544 PG 4 WC Geosciences, Multidisciplinary SC Geology GA MY140 UT WOS:A1994MY14000014 ER PT J AU ITO, RY HAWN, DR COLLETTE, BB AF ITO, RY HAWN, DR COLLETTE, BB TI 1ST RECORD OF THE BUTTERFLY KINGFISH GASTEROCHISMA-MELAMPUS (SCOMBRIDAE) FROM THE NORTH PACIFIC-OCEAN SO JAPANESE JOURNAL OF ICHTHYOLOGY LA English DT Note C1 NOAA,NATL MUSEUM NAT HIST,NATL MARINE FISHERIES SERV,NATL SYSTEMAT LAB,WASHINGTON,DC 20560. RP ITO, RY (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 12 TC 1 Z9 2 U1 0 U2 0 PU ICHTHYOLOGICAL SOC JAPAN PI TOKYO PA BUSINESS CENTER ACADEMIC SOC JAPAN, 5-16-9 HONKOMAGOME, BUNKYO-KU, TOKYO 113, JAPAN SN 0021-5090 J9 JPN J ICHTHYOL JI Jpn. J. Ichthyol. PD FEB 15 PY 1994 VL 40 IS 4 BP 482 EP 486 PG 5 WC Fisheries; Zoology SC Fisheries; Zoology GA MY234 UT WOS:A1994MY23400011 ER PT J AU MA, Q TIPPING, RH AF MA, Q TIPPING, RH TI A NEAR-WING CORRECTION TO THE QUASI-STATIC FAR-WING LINE-SHAPE THEORY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID WATER CONTINUUM ABSORPTION; ROTATIONAL BANDS AB A new representation is introduced in which the rapidly varying time-dependent part of the time displacement operator can be factored out and the remaining part, which varies with time more slowly, can be expanded in the usual perturbational fashion. The lowest order approximation leads to the far-wing quasistatic line shape theory developed previously, whereas the next order approximation, related to the noncommutation of the Liouville operators describing the unperturbed absorber and bath molecules and the interaction between them, leads to a near-wing correction. Explicit expressions are derived for both the corrections to the spectral density and the statistical band-average line shape function assuming an anisotropic dipole-dipole interaction. Detailed computations for the case of self-broadened H2O are carried out for the line-shapes and the corresponding absorption coefficients for several temperatures and for frequencies to 10 000 cm(-1). From these results, we conclude that the near-wing corrections generally increase the line shape function between 10 and 200 cm(-1), and that this increase is more important for lower temperatures than for higher ones. This in turn leads to increased absorption-nearer the band centers, especially for lower temperatures, and thus to improved agreement between theory and experiment. C1 GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025. UNIV ALABAMA,DEPT PHYS & ASTRON,TUSCALOOSA,AL 35487. RP MA, Q (reprint author), COLUMBIA UNIV,DEPT APPL PHYS,NEW YORK,NY 10025, USA. NR 16 TC 8 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1994 VL 100 IS 4 BP 2537 EP 2546 DI 10.1063/1.466502 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA MX628 UT WOS:A1994MX62800015 ER PT J AU WHITTENBERGER, JD FARMER, SC BORS, DA RAY, R LEE, DS AF WHITTENBERGER, JD FARMER, SC BORS, DA RAY, R LEE, DS TI ELEVATED-TEMPERATURE DEFORMATION PROPERTIES OF A HFC MODIFIED TI-48AL-2MN-2NB MATRIX PARTICULATE COMPOSITE SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ALLOYS; FLOW AB Rapid solidification techniques in combination with HIPing have been used to produce Ti-48Al-2Mn-2Nb and a Ti-48Al-2Mn-2Nb+15 wt% HfC composite. While the composite does contain several second phases within the gamma + alpha2 matrix, none was identified to be HfC. The elevated-temperature properties were determined by constant velocity compression and constant load tensile testing in air between 1000 and 1173 K. Such testing indicated that the elevated temperature strengths of the HfC-modified aluminide was superior to those of the unreinforced matrix with the best 1100 K temperature slow strain rate properties for both materials being achieved after high-temperature annealing prior to testing. Examination of the microstructures after deformation in combination with the measured stress exponents and activation energies suggest that creep resistance of the HfC-modified form is due to solid-solution strengthening from carbon and hafnium rather than the presence of second phases. C1 MARKO MAT INC,N BILLERICA,MA 01862. MAT LAB,WRIGHT PATTERSON AFB,OH 45433. RP WHITTENBERGER, JD (reprint author), NASA,LEWIS RES CTR,CALSPAN CORP,CLEVELAND,OH 44135, USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD FEB 15 PY 1994 VL 29 IS 4 BP 851 EP 860 DI 10.1007/BF00351401 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA MZ023 UT WOS:A1994MZ02300001 ER PT J AU DODELSON, S JUBAS, JM AF DODELSON, S JUBAS, JM TI COSMOLOGICAL SIGNATURES OF DECAYING DARK-MATTER SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ELEMENTARY PARTICLES; RADIATION MECHANISMS NONTHERMAL; INTERGALACTIC MEDIUM; COSMOLOGY OBSERVATIONS; DARK MATTER; DIFFUSE RADIATION ID LYMAN-ALPHA CLOUDS; H-I REGIONS; GALACTIC HALO; HIGH-REDSHIFT; BACKGROUND-RADIATION; ABSORPTION SYSTEMS; HYPOTHESIS; GALAXY; REIONIZATION; TELESCOPE AB The decaying dark matter (DDM) scenario is a viable way of ionizing the Universe at high redshifts. We examine the constraints on this scenario due to the diffuse ultraviolet flux and Gunn-Peterson tests. The latter require the decaying particle's lifetime to be less than approximately 10(23) S. Observations of the diffuse UV flux along with a conservative estimate of its Galactic component require the DDM particle to have mass greater than 28.5 eV. With larger estimates of the Galactic contribution to the UV flux, the limit becomes m > 34.5 Ev. We also point out a distinctive signature of DDM: a sharp drop in the infrared part of the spectrum. C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP DODELSON, S (reprint author), NASA,FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,BOX 500,BATAVIA,IL 60510, USA. NR 51 TC 11 Z9 11 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 15 PY 1994 VL 266 IS 4 BP 886 EP 890 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MW545 UT WOS:A1994MW54500014 ER PT J AU MASTICHIADIS, A PROTHEROE, RJ SZABO, AP AF MASTICHIADIS, A PROTHEROE, RJ SZABO, AP TI THE EFFECT OF TRIPLET PRODUCTION ON PAIR COMPTON CASCADES IN THERMAL-RADIATION SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE RADIATION MECHANISMS NONTHERMAL; RADIATIVE TRANSFER; GAMMA-RAYS THEORY ID ACTIVE GALACTIC NUCLEI; SOFT PHOTON FIELD; X-RAY SOURCES; ULTRARELATIVISTIC ELECTRONS; SPECTRA AB We calculate the spectrum of photons resulting from electromagnetic cascades through thermal radiation, and examine the consequences of including triplet production in these cascades. We assume that the cascade is one-dimensional, and we find that this approximation is justified in the present work for thermal radiation with temperature less than 10(-3) mc2. Results are obtained for both monoenergetic and power-law primary spectra, and for a variety of path lengths. We find that triplet production is particularly important in electron photon cascades through thermal radiation when the primary energy exceeds 10(5) m2c4/kT for propagation over small path lengths. The importance of triplet production decreases as the path length increases, and it has no effect on saturated cascades. C1 UNIV ADELAIDE,DEPT PHYS & MATH PHYS,ADELAIDE,SA 5005,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. NR 18 TC 9 Z9 9 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 15 PY 1994 VL 266 IS 4 BP 910 EP 916 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MW545 UT WOS:A1994MW54500018 ER PT J AU WYNANDS, HA MALTA, DM FOX, BA VONWINDHEIM, JA FLEURIAL, JP IRVINE, D VANDERSANDE, J AF WYNANDS, HA MALTA, DM FOX, BA VONWINDHEIM, JA FLEURIAL, JP IRVINE, D VANDERSANDE, J TI IMPURITY-CHARACTERIZATION AGREEMENT IN TYPE-IIB SINGLE-CRYSTAL DIAMOND BY HIGH-TEMPERATURE HALL-EFFECT, CAPACITANCE-VOLTAGE, AND SECONDARY-ION MASS-SPECTROSCOPY MEASUREMENTS SO PHYSICAL REVIEW B LA English DT Note ID SEMICONDUCTING DIAMOND AB The acceptor concentration of two type-IIb natural diamonds has been measured by Hall effect (to 1300 K), capacitance-voltage (CV), and secondary-ion mass-spectroscopy measurements. Reduction of contact effects in both Hall and CV measurements resulted in excellent agreement between the three techniques. Hall contact size and placement effects were measured and corrected. The capacitance and resistance of the Ohmic contact for CV measurements were minimized with a large-area ion-implanted contact. The long-standing discrepancy between Hall-effect and CV results in diamond is shown to be primarily due to nonideal CV contacts. C1 JET PROP LAB,PASADENA,CA 91109. RP WYNANDS, HA (reprint author), KOBE STEEL USA INC,CTR ELECTR MAT,79 TW ALEXANDER DR,4401 BLDG,POB 13608,RES TRIANGLE PK,NC 27709, USA. NR 19 TC 8 Z9 9 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1994 VL 49 IS 8 BP 5745 EP 5748 DI 10.1103/PhysRevB.49.5745 PG 4 WC Physics, Condensed Matter SC Physics GA MY972 UT WOS:A1994MY97200081 ER PT J AU ABNEY, M AF ABNEY, M TI HYDRODYNAMIC DETONATION INSTABILITY IN ELECTROWEAK AND QCD PHASE-TRANSITIONS SO PHYSICAL REVIEW D LA English DT Article ID BUBBLE-GROWTH; NUCLEATION; WAVES AB The hydrodynamic stability of deflagration and detonation bubbles for a first order electroweak and QCD phase transition has been discussed recently with the suggestion that detonations are stable. We examine here the case of a detonation more carefully. We find that in front of the bubble wall perturbations do not grow with time, but behind the wall modes exist which grow exponentially. We briefly discuss the possible meaning of this instability. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP ABNEY, M (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 19 TC 14 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1994 VL 49 IS 4 BP 1777 EP 1782 DI 10.1103/PhysRevD.49.1777 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MY971 UT WOS:A1994MY97100011 ER PT J AU COPELAND, EJ KOLB, EW LIDDLE, AR LIDSEY, JE AF COPELAND, EJ KOLB, EW LIDDLE, AR LIDSEY, JE TI RECONSTRUCTING THE INFLATON POTENTIAL - PERTURBATIVE RECONSTRUCTION TO 2ND-ORDER SO PHYSICAL REVIEW D LA English DT Article ID GRAVITATIONAL-WAVES; INFLATIONARY UNIVERSE; EXTENDED INFLATION; COBE; FLATNESS; SCENARIO; HORIZON AB One method to reconstruct the scalar field potential of inflation is a perturbative approach, where the values of the potential and its derivatives are calculated as an expansion in departures from the slow-roll approximation. They can then be expressed in terms of observable quantities, such as the square of the ratio of the gravitational wave amplitude to the density perturbation amplitude, the deviation of the spectral index from the Harrison-Zel'dovich value, etc. Here, we calculate complete expressions for the second-order contributions to the coefficients of the expansion by including for the first time corrections to the standard expressions for the perturbation spectra. As well as offering an improved result, these corrections indicate the expected accuracy of the reconstruction. Typically the corrections are only a few percent. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP COPELAND, EJ (reprint author), UNIV SUSSEX,SCH MATH & PHYS SCI,CTR ASTRON,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. NR 28 TC 72 Z9 72 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1994 VL 49 IS 4 BP 1840 EP 1844 DI 10.1103/PhysRevD.49.1840 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA MY971 UT WOS:A1994MY97100014 ER PT J AU GAYDA, J GABB, TP AF GAYDA, J GABB, TP TI THE EFFECT OF FIBER CONTENT ON THE FATIGUE LIFE OF SCS6 TI-15-3 COMPOSITE SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID MATRIX AB The fatigue life of unidirectional SCS6/Ti-15-3 composite was enhanced by higher fiber content at room temperature and 550C on a stress-basis. A strain-based comparison collapsed fatigue life for all fiber contents at 550C; however, modest differences in fatigue life were observed for different fiber contents at room temperature. These differences were thought to be related to variations in residual stress levels, fiber bridging and fiber spacing/damage considerations. Matrix relaxation and environmental attack were believed to reduce or counteract these factors at 550C. RP GAYDA, J (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB 15 PY 1994 VL 30 IS 4 BP 469 EP 474 DI 10.1016/0956-716X(94)90605-X PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA MN519 UT WOS:A1994MN51900015 ER PT J AU MCKENNA, JT AF MCKENNA, JT TI DISCOVERY OVERCOMES GLITCHES TO PLUMB SPACES VACUUM SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Article RP MCKENNA, JT (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD FEB 14 PY 1994 VL 140 IS 7 BP 27 EP 28 PG 2 WC Engineering, Aerospace SC Engineering GA NF335 UT WOS:A1994NF33500014 ER PT J AU JESSUP, JM FORD, RD GOODWIN, TJ WOLF, DA SPAULDING, G AF JESSUP, JM FORD, RD GOODWIN, TJ WOLF, DA SPAULDING, G TI GROWTH OF HUMAN COLORECTAL-CARCINOMA CELLS IN NASA ROTATING WALL VESSEL (RWV) PRODUCES HIGH CELL YIELDS WITH DIFFERENTIATION AND REDUCED GLUCOSE CONSUMPTION SO JOURNAL OF CELLULAR BIOCHEMISTRY LA English DT Meeting Abstract C1 NEW ENGLAND DEACONESS HOSP,BOSTON,MA 02215. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0730-2312 J9 J CELL BIOCHEM JI J. Cell. Biochem. PD FEB 13 PY 1994 SU 18C BP 275 EP 275 PG 1 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA MY175 UT WOS:A1994MY17500971 ER PT J AU WEAVER, HA FELDMAN, PD AHEARN, MF ARPIGNY, C BROWN, RA HELIN, EF LEVY, DH MARSDEN, BG MEECH, KJ LARSON, SM NOLL, KS SCOTTI, JV SEKANINA, Z SHOEMAKER, CS SHOEMAKER, EM SMITH, TE STORRS, AD YEOMANS, DK ZELLNER, B AF WEAVER, HA FELDMAN, PD AHEARN, MF ARPIGNY, C BROWN, RA HELIN, EF LEVY, DH MARSDEN, BG MEECH, KJ LARSON, SM NOLL, KS SCOTTI, JV SEKANINA, Z SHOEMAKER, CS SHOEMAKER, EM SMITH, TE STORRS, AD YEOMANS, DK ZELLNER, B TI HUBBLE-SPACE-TELESCOPE OBSERVATIONS OF COMET-P/SHOEMAKER-LEVY-9 (1993E) SO SCIENCE LA English DT Article ID FIELD PLANETARY CAMERA AB The Hubble Space Telescope observed the fragmented comet P/Shoemaker-Levy 9 (1993e) (P indicates that it is a periodic comet) on 1 July 1993. Approximately 20 individual nuclei and their comae were observed in images taken with the Planetary Camera. After subtraction of the comae light, the 11 brightest nuclei have magnitudes between approximately 23.7 and 24.8. Assuming that the geometric albedo is 0.04, these magnitudes imply that the nuclear diameters are in the range approximately 2.5 to 4.3 kilometers. If the density of each nucleus is 1 gram per cubic centimeter, the total energy deposited by the impact of these 11 nuclei into Jupiter's atmosphere next July will be approximately 4 x 10(30) ergs (approximately 10(8) megatons of TNT). This latter number should be regarded as an upper limit because the nuclear magnitudes probably contain a small residual coma contribution. The Faint Object Spectrograph was used to search for fluorescence from OH, which is usually an excellent indicator of cometary activity. No OH emission was detected, and this can be translated into an upper limit on the water production rate of approximately 2 x 10(27) molecules per second. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. STATE UNIV LIEGE,INST ASTROPHYS,B-4000 LIEGE,BELGIUM. JET PROP LAB,PASADENA,CA 91109. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. NO ARIZONA UNIV,DEPT PHYS & ASTRON,FLAGSTAFF,AZ 86011. US GEOL SURVEY,FLAGSTAFF,AZ 86001. SPACE TELESCOPE SCI INST,COMP SCI CORP,ASTRON PROGRAM,BALTIMORE,MD 21218. RP WEAVER, HA (reprint author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA. RI Noll, Keith/C-8447-2012; Weaver, Harold/D-9188-2016 NR 27 TC 46 Z9 47 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 11 PY 1994 VL 263 IS 5148 BP 787 EP 791 DI 10.1126/science.263.5148.787 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MV866 UT WOS:A1994MV86600028 PM 17770832 ER PT J AU REID, MB AF REID, MB TI OPTICAL CALCULATION OF POTENTIAL FIELDS FOR ROBOTIC PATH PLANNING SO APPLIED OPTICS LA English DT Article ID SPATIAL LIGHT-MODULATOR AB Experimental results of the optical calculation of potential-field maps suitable for mobile robot navigation are presented and described. The optical computation employs two write modes of a microchannel spatial light modulator. In one mode, written patterns expand spatially, and this characteristic is used to create an extended two-dimensional function representing the influence of the goal in a robot's workspace. Distinct obstacle patterns are written in a second, nonexpanding, mode. A model of the mechanisms determining microchannel spatial light modulator write-mode characteristics is developed and used to derive the optical calculation time for full potential-field maps. Field calculations at a few hertz are possible with current technology, and calculation time versus map size scales favorably in comparison with digital electronic computation. RP REID, MB (reprint author), NASA, AMES RES CTR, DIV INFORMAT SCI, PHOTON GRP, MOFFETT FIELD, CA 94035 USA. NR 27 TC 1 Z9 1 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 10 PY 1994 VL 33 IS 5 BP 881 EP 896 PG 16 WC Optics SC Optics GA MY853 UT WOS:A1994MY85300020 PM 20862088 ER PT J AU TAUBER, JA TIELENS, AGGM MEIXNER, M GOLDSMITH, PF AF TAUBER, JA TIELENS, AGGM MEIXNER, M GOLDSMITH, PF TI ANATOMY OF A PHOTODISSOCIATION REGION - HIGH ANGULAR RESOLUTION IMAGES OF MOLECULAR-EMISSION IN THE ORION BAR SO ASTROPHYSICAL JOURNAL LA English DT Article DE H II REGIONS; ISM, INDIVIDUAL (ORION NEBULA); ISM, MOLECULES; RADIO LINES, ISM ID ROTATIONAL EMISSION; CLUMPY STRUCTURE; CARBON-MONOXIDE; LINE EMISSION; BRIGHT BAR; CLOUDS; HYDROGEN; NEBULA; GAS; MODEL AB We present observations of the molecular component of the Orion Bar, a prototypical Photodissociation Region (PDR) illuminated by the Trapezium cluster. The high angular resolution (6''-10'') that we have achieved by combining single-dish and interferometric observations has allowed us to examine in detail the spatial and kinematic morphology of this region and to estimate the physical characteristics of the molecular gas it contains. Our observations indicate that this PDR can be essentially described as a homogeneously distributed slab of moderately dense material (similar to 5 x 10(4) cm(-3)), in which are embedded a small number of dense (>10(6) cm(-3)) clumps. The latter play little or no role in determining the thickness and kinetic temperature structure of this PDR. This observational picture is largely supported by PDR model calculations for this region, which we describe in detail in this work. We also find our model predictions of the intensities of a variety of atomic and molecular lines to be in good general agreement with a number of previous observations. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. CORNELL UNIV,DEPT ASTRON,NATL ASTRON & IONOSPHERE CTR,ITHACA,NY 14853. ESTEC,EUROPEAN SPACE AGCY,DIV ASTROPHYS,2201 AZ NOORDWIJK,NETHERLANDS. UNIV MASSACHUSETTS,FIVE COLL RADIO ASTRON OBSERV,AMHERST,MA 01001. UNIV MASSACHUSETTS,DEPT PHYS,AMHERST,MA 01001. RP TAUBER, JA (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,BERKELEY,CA 94720, USA. RI Goldsmith, Paul/H-3159-2016 NR 48 TC 59 Z9 59 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1994 VL 422 IS 1 BP 136 EP 152 DI 10.1086/173711 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU690 UT WOS:A1994MU69000013 ER PT J AU SCHLEGEL, EM MARSHALL, FE MUSHOTZKY, RF SMALE, AP WEAVER, KA SERLEMITSOS, PJ PETRE, R JAHODA, KM AF SCHLEGEL, EM MARSHALL, FE MUSHOTZKY, RF SMALE, AP WEAVER, KA SERLEMITSOS, PJ PETRE, R JAHODA, KM TI A BROAD-BAND X-RAY TELESCOPE OBSERVATION OF THE BLACK-HOLE CANDIDATE LMC X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BLACK HOLE PHYSICS; STARS, INDIVIDUAL (LMC X-1); X-RAYS, STARS ID ACCRETION DISKS; LINE EMISSION; DISCOVERY; SPECTRA; SS433 AB We present the spectrum of the black hole candidate LMC X-1 as observed by the Broad-Band X-ray Telescope. The spectrum cannot be fitted by a simple model, but it requires a soft disk blackbody component and a power-law tail, confirming earlier studies. The blackbody disk component is essentially unchanged since the Ginga measurement in 1987. The implied mass of the compact object is similar to 4.7 root cos i M. from the soft component fit. We report a 95% confidence detection of weak emission features at similar to 5.1 keV and similar to-7.3 keV. If the 5.1 keV feature is attributed to Fe I K alpha at 6.39 keV, then the redshift is similar to 0.19. No quasi-periodic behavior is found in the data at this epoch. C1 UNIV SPACE RES ASSOC,GREENBELT,MD. UNIV MARYLAND,GREENBELT,MD. RP SCHLEGEL, EM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 668,GREENBELT,MD 20771, USA. NR 29 TC 21 Z9 21 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1994 VL 422 IS 1 BP 243 EP 247 DI 10.1086/173722 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU690 UT WOS:A1994MU69000024 ER PT J AU HUDSON, HS STRONG, KT DENNIS, BR ZARRO, D INDA, M KOSUGI, T SAKAO, T AF HUDSON, HS STRONG, KT DENNIS, BR ZARRO, D INDA, M KOSUGI, T SAKAO, T TI IMPULSIVE BEHAVIOR IN SOLAR SOFT X-RADIATION SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, CHROMOSPHERE; SUN, FLARES; SUN, X-RAYS, GAMMA RAYS ID RAY TELESCOPE; A MISSION; FLARES; EMISSION; MORPHOLOGY; PLASMA AB The Yohkoh soft X-ray telescope has observed impulsive, thermal, soft X-ray emission at the footpoints of magnetic loops during solar flares. The soft X-ray (thermal) time profiles at the footpoints closely match the hard X-ray (nonthermal) time profiles, directly demonstrating the heating of the lower solar atmosphere on short timescales during the interval of nonthermal energy release. This phenomenon is the rule, rather than the exception, occurring in the majority of flares that we have examined with the Yohkoh data. We illustrate the impulsive behavior with data from the major flare of 1992 January 26. For this flare, the soft X-ray peak times matched the hard X-ray peak times within the time resolution of the soft X-ray measurements (about 10 s), and the soft and hard X-ray locations match within the resolution of the hard X-ray imager. The impulsive soft X-ray emission clearly has a thermal spectral signature, but not at the high temperature of a ''superhot'' source. We conclude that the impulsive soft X-ray emission comes from material heated by precipitating electrons at loop footpoints and evaporating from the deeper atmosphere into the flaring flux tube. C1 NASA,GODDARD SPACE FLIGHT CTR,CTR SOLAR DATA ANAL,GREENBELT,MD 20771. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. UNIV TOKYO,DEPT PHYS,BUNKYO KU,TOKYO 113,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. NATL ASTRON OBSERV JAPAN,MITAKA,TOKYO 181,JAPAN. RP HUDSON, HS (reprint author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA. RI Dennis, Brian/C-9511-2012 NR 27 TC 80 Z9 80 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1994 VL 422 IS 1 BP L25 EP & DI 10.1086/187203 PN 2 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU691 UT WOS:A1994MU69100007 ER PT J AU KUMAR, P FARDAL, MA JEFFERIES, SM DUVALL, TL HARVEY, JW POMERANTZ, MA AF KUMAR, P FARDAL, MA JEFFERIES, SM DUVALL, TL HARVEY, JW POMERANTZ, MA TI LIMITS ON CORONAL REFLECTION USING HIGH-FREQUENCY SOLAR OSCILLATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, ATMOSPHERE; SUN, OSCILLATIONS AB Acoustic waves in the Sun with frequencies above about 5.3 mHz can propagate in the chromosphere. We examine imaged solar intensity data for evidence of reflection of these waves in the upper chromosphere, where the temperature increases by a large factor over a short distance. Our method is to compare the observed and theoretically derived frequency spacings between peaks in the power spectrum. We find that our theoretical frequencies provide the best fit to the data when the reflection in the upper atmosphere is eliminated. In particular, the model of Kumar (1993b), which includes the source depth, and radiative damping, in the calculation of power spectra but ignores chromospheric reflection, gives peak frequencies that are in good agreement with the observations. For acoustic waves of frequency greater than 6 mHz we put an upper limit to the reflectivity of chromosphere and corona, using our method, of about 10%. At a given spherical harmonic degree, the frequency spacing between peaks in the data generally decreases with increasing frequency, because the lower turning point of the waves is moving inward. However, between 5 and 5.5 mHz the frequency spacing increases slightly. This feature is probably associated with the acoustic cutoff frequency in the solar atmosphere, i.e., it indicates a transition from trapped waves to propagating waves. We are able to reproduce the observed behavior by a crude modeling of the solar atmosphere. Further study of these peaks should provide an independent way of exploring the mean structure of the solar atmosphere, particularly around the temperature minimum region. C1 UNIV DELAWARE, BARTOL RES INST, NEWARK, DE 19716 USA. UNIV COLORADO, APAS, BOULDER, CO 80309 USA. UNIV COLORADO, CASA, BOULDER, CO 80309 USA. UNIV COLORADO, JILA, BOULDER, CO 80309 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. NATL OPT ASTRON OBSERV, NATL SOLAR OBSERV, TUCSON, AZ 85726 USA. RP MIT, DEPT PHYS, CAMBRIDGE, MA 02139 USA. RI Duvall, Thomas/C-9998-2012 NR 15 TC 18 Z9 18 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1994 VL 422 IS 1 BP L29 EP L32 DI 10.1086/187204 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU691 UT WOS:A1994MU69100008 ER PT J AU COLONIUS, T LELE, SK MOIN, P AF COLONIUS, T LELE, SK MOIN, P TI THE SCATTERING OF SOUND-WAVES BY A VORTEX - NUMERICAL SIMULATIONS AND ANALYTICAL SOLUTIONS SO JOURNAL OF FLUID MECHANICS LA English DT Article AB The scattering of plane sound waves by a vortex is investigated by solving the compressible Navier-Stokes equations numerically, and analytically with asymptotic expansions. Numerical errors associated with discretization and boundary conditions are made small by using high-order-accurate spatial differentiation and time marching schemes along with accurate non-reflecting boundary conditions. The accuracy of computations of flow fields with acoustic waves of amplitude five orders of magnitude smaller than the hydrodynamic fluctuations is directly verified. The properties of the scattered field are examined in detail. The results reveal inadequacies in previous vortex scattering theories when the circulation of the vortex is non-zero and refraction by the slowly decaying vortex flow field is important. Approximate analytical solutions that account for the refraction effect are developed and found to be in good agreement with the computations and experiments. C1 STANFORD UNIV,DEPT AERONAUT & ASTRONAUT,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP COLONIUS, T (reprint author), STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305, USA. NR 20 TC 68 Z9 72 U1 0 U2 5 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD FEB 10 PY 1994 VL 260 BP 271 EP 298 DI 10.1017/S0022112094003514 PG 28 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA MZ163 UT WOS:A1994MZ16300011 ER PT J AU NEREM, RS LERCH, FJ WILLIAMSON, RG KLOSKO, SM ROBBINS, JW PATEL, GB AF NEREM, RS LERCH, FJ WILLIAMSON, RG KLOSKO, SM ROBBINS, JW PATEL, GB TI GRAVITY MODEL IMPROVEMENT USING THE DORIS TRACKING SYSTEM ON THE SPOT-2 SATELLITE SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GRAVITATIONAL MODEL; THERMOSPHERIC MODEL; ANOMALIES; GEM-T1; FIELD; EARTH AB A high-precision radiometric satellite tracking system, DORIS, has recently been developed by the French space agency, Centre National d'Etudes Spatiales (CNES). DORIS was designed to provide tracking support for missions such as the joint United States/French TOPEX/Poseidon. As part of the flight testing process, a DORIS package was flown on the French SPOT 2 satellite. A substantial quantity of geodetic quality tracking data was obtained on SPOT 2 from an extensive international DORIS tracking network. These data were analyzed to assess their accuracy and to evaluate the gravitational modeling enhancements provided by these data in combination with the GEM-T3 gravitational model. These observations have noise levels of 0.4 to 0.5 mm/s, with few residual systematic effects. Although the SPOT 2 satellite experiences high atmospheric drag forces, the precision and global coverage of the DORIS tracking data have enabled more extensive orbit parameterization to mitigate these effects. As a result, the SPOT 2 orbital errors have been reduced to an estimated radial accuracy in the 10-20 cm RMS range, The addition of these data, which encompass many regions heretofore lacking in precision satellite tracking, has significantly improved GEM-T3 and allowed greatly improved orbit accuracies for Sun-synchronous satellites like SPOT 2 (such as ERS 1 and EOS). Comparison of the ensuing gravity model with other contemporary fields (GRIM-4C2, TEG2B, and OSU91A) provides a means to assess the current state of knowledge of the Earth's gravity field. Thus, the DORIS experiment on SPOT 2 has provided a strong basis For evaluating this new orbit tracking technology and has demonstrated the important contribution of the DORIS network to the success of the TOPEX/Poseidon mission. C1 HUGHES STX CORP, LANHAM, MD USA. RP NEREM, RS (reprint author), NASA, GODDARD SPACE FLIGHT CTR, SPACE GEODESY BRANCH, CODE 926, GREENBELT, MD 20771 USA. NR 44 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1994 VL 99 IS B2 BP 2791 EP 2813 DI 10.1029/93JB02567 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA MW736 UT WOS:A1994MW73600016 ER PT J AU LERCH, FJ NEREM, RS PUTNEY, BH FELSENTREGER, TL SANCHEZ, BV MARSHALL, JA KLOSKO, SM PATEL, GB WILLIAMSON, RG CHINN, DS CHAN, JC RACHLIN, KE CHANDLER, NL MCCARTHY, JJ LUTCKE, SB PAVLIS, NK PAVLIS, DE ROBBINS, JW KAPOOR, S PAVLIS, EC AF LERCH, FJ NEREM, RS PUTNEY, BH FELSENTREGER, TL SANCHEZ, BV MARSHALL, JA KLOSKO, SM PATEL, GB WILLIAMSON, RG CHINN, DS CHAN, JC RACHLIN, KE CHANDLER, NL MCCARTHY, JJ LUTCKE, SB PAVLIS, NK PAVLIS, DE ROBBINS, JW KAPOOR, S PAVLIS, EC TI A GEOPOTENTIAL MODEL FROM SATELLITE TRACKING, ALTIMETER, AND SURFACE GRAVITY-DATA - GEM-T3 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GRAVITATIONAL MODEL; ORBIT; STARLETTE; MOTION; LAGEOS; FIELD; EARTH AB An improved model of Earth's gravitational field, GEM-T3, has been developed from a combination of satellite tracking, satellite altimeter, and surface gravimetric data. GEM-T3 provides a significant improvement in the modeling of the gravity field at half wavelengths of 400 km and longer. This model, complete to degree and order 50, yields more accurate satellite orbits and an improved geoid representation than previous Goddard Earth Models. GEM-T3 uses altimeter data from GEOS 3 (1975-1976), Seasat (1978) and Geosat (1986-1987). Tracking information used in the solution includes more than 1300 arcs of data encompassing 31 different satellites. The recovery of the long-wavelength components of the solution relies mostly on highly precise satellite laser ranging (SLR) data, but also includes TRANET Doppler, optical, and satellite-to-satellite tracking acquired between the ATS 6 and GEOS 3 satellites. The main advances over GEM-T2 (beyond the inclusion of altimeter and surface gravity information which is essential For the resolution of the shorter wavelength geoid) are some improved tracking data analysis approaches and additional SLR data. Although the use of altimeter data his greatly enhanced the modeling of the ocean geoid between 65-degrees-N and 60-degrees-S latitudes in GEM-T3, the lack of accurate detailed surface gravimetry leaves poor geoid resolution over many continental regions of great tectonic interest (e.g., Himalayas, Andes). Estimates of polar motion, tracking station coordinates, and long-wavelength ocean tidal terms were also made (accounting for 6330 parameters), (GFM-T3 has undergone error calibration using a technique based on subset solutions to produce reliable error estimates. The calibration is based on the condition that the expected mean square deviation of a subset gravity solution from the full set values is predicted by the solutions' error covariances. Data weights are iteratively adjusted until this condition for the error calibration is satisfied. In addition, gravity field tests were performed on strong satellite data sets withheld from the solution (thereby ensuring their independence). In these tests, the performance of the subset models on the withheld observations is compared to error projections based on their calibrated error covariances. These results demonstrate that orbit accuracy projections are reliable for new satellites which were not included in GEM-T3. C1 HUGHES STX CORP, LANHAM, MD USA. UNIV MARYLAND, DEPT ASTRON, GREENBELT, MD USA. RP LERCH, FJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, SPACE GEODESY BRANCH, CODE 926, GREENBELT, MD 20771 USA. RI Sanchez, Braulio/I-5952-2013 NR 50 TC 43 Z9 44 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1994 VL 99 IS B2 BP 2815 EP 2839 DI 10.1029/93JB02759 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA MW736 UT WOS:A1994MW73600017 ER PT J AU BRENTNER, KS FARASSAT, F AF BRENTNER, KS FARASSAT, F TI HELICOPTER NOISE PREDICTION - THE CURRENT STATUS AND FUTURE-DIRECTION SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID TRAILING EDGE NOISE; BROAD-BAND NOISE; ROTOR; ACOUSTICS RP BRENTNER, KS (reprint author), NASA,LANGLEY RES CTR,DIV ACOUST,HAMPTON,VA 23665, USA. NR 99 TC 26 Z9 30 U1 2 U2 7 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD FEB 10 PY 1994 VL 170 IS 1 BP 79 EP 96 DI 10.1006/jsvi.1994.1047 PG 18 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA MW767 UT WOS:A1994MW76700004 ER PT J AU RICH, DH RAMMOHAN, K TANG, Y LIN, HT MASERJIAN, J GRUNTHANER, FJ LARSSON, A BORENSTAIN, SI AF RICH, DH RAMMOHAN, K TANG, Y LIN, HT MASERJIAN, J GRUNTHANER, FJ LARSSON, A BORENSTAIN, SI TI AMBIPOLAR DIFFUSION ANISOTROPY INDUCED BY DEFECTS IN NIPI-DOPED IN0.2GA0.8AS/GAAS MULTIPLE-QUANTUM WELLS SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; GAAS AB The influence of strain-induced defects on the ambipolar diffusive transport of excess electrons and holes in the delta-doped InGaAs/GaAs multiple quantum well system has been examined with a new technique called electron-beam-induced absorption modulation (EBIA). The excess carrier lifetime and diffusion coefficient are obtained by a one-dimensional diffusion experiment that utilizes EBIA. An anisotropy in the ambipolar diffusion along both high-symmetry [110] directions is found, and this is seen to correlate with the distribution of dark line defects observed in cathodoluminescence. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. CHALMERS UNIV TECHNOL,DEPT OPTOELECTR & ELECT MEASUREMENTS,S-41296 GOTHENBURG,SWEDEN. JERUSALEM COLL TECHNOL,IL-91160 JERUSALEM,ISRAEL. RP RICH, DH (reprint author), UNIV SO CALIF,DEPT MAT SCI & ENGN,PHOTON MAT & DEVICES LAB,LOS ANGELES,CA 90089, USA. RI Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 9 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 7 PY 1994 VL 64 IS 6 BP 730 EP 732 DI 10.1063/1.111048 PG 3 WC Physics, Applied SC Physics GA MV501 UT WOS:A1994MV50100021 ER PT J AU BRASUNAS, JC LAKEW, B AF BRASUNAS, JC LAKEW, B TI HIGH T-C SUPERCONDUCTOR BOLOMETER WITH RECORD PERFORMANCE SO APPLIED PHYSICS LETTERS LA English DT Article AB We have used prethinned sapphire substrates to make a YBa2Cu3O7-x thin-film, transition-edge bolometer with peak detectivity of 6x10(9) cm Hz(1/2)/W near 4 Hz and 90 K. This is a new record for high T-c superconductor bolometers, and is comparable to the best detectivity yet achieved for a thermal-type infrared detector with no more than moderate cooling (liquid-nitrogen temperature and above). We discuss some simple improvements which may push the detectivity above 10(10). C1 HUGHES STX CORP,LANHAM,MD 20706. RP BRASUNAS, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI brasunas, john/I-2798-2013 NR 10 TC 61 Z9 63 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 7 PY 1994 VL 64 IS 6 BP 777 EP 778 DI 10.1063/1.111010 PG 2 WC Physics, Applied SC Physics GA MV501 UT WOS:A1994MV50100037 ER PT J AU ROBERTS, GD HO, BPH WALLACE, JF AF ROBERTS, GD HO, BPH WALLACE, JF TI EFFECTS OF THERMAL AND MECHANICAL FATIGUE ON FLEXURAL STRENGTH OF G40-600/PMR-15 CROSS-PLY LAMINATES SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article AB The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientations of (0(2), 90(2))2s and (90(2), 0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposure of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0-degrees ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the ''apparent'' strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32-260-degrees-C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to 85-degrees-C, 500 cycles). Mechanical cycling (0-50% of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue. (C) 1994 John Wiley & Sons, Inc.(double dagger) C1 CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP ROBERTS, GD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD FEB 7 PY 1994 VL 51 IS 6 BP 1107 EP 1118 DI 10.1002/app.1994.070510617 PG 12 WC Polymer Science SC Polymer Science GA MR268 UT WOS:A1994MR26800017 ER PT J AU CHEN, CT MARDER, SR CHENG, LT AF CHEN, CT MARDER, SR CHENG, LT TI MOLECULAR FIRST HYPERPOLARIZABILITIES OF A NEW CLASS OF ASYMMETRIC SQUARAINE DYES SO JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS LA English DT Article ID NONLINEAR OPTICAL POLARIZABILITIES; STILBENE DERIVATIVES; CHEMISTRY AB The molecular first hyperpolarizabilities (beta) of a series of asymmetric squaraine dyes have been measured by electric-field-induced second harmonic generation; the dyes have negative beta-values whose magnitudes are comparable to 4-N,N-dimethylamino-4'-nitrostilbene (DANS). C1 CALTECH,BECKMAN INST,CTR MOLEC MAT RESOURCE,PASADENA,CA 91125. CALTECH,JET PROP LAB,PASADENA,CA 91109. DUPONT CO INC,CENT RES & ENGN LABS,WILMINGTON,DE 19880. RI Chen, Chin-Ti/E-5341-2015 NR 21 TC 50 Z9 52 U1 0 U2 2 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0022-4936 J9 J CHEM SOC CHEM COMM JI J. Chem. Soc.-Chem. Commun. PD FEB 7 PY 1994 IS 3 BP 259 EP 260 DI 10.1039/c39940000259 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA MX131 UT WOS:A1994MX13100010 ER PT J AU RICO, RJ LEE, TJ HEADGORDON, M AF RICO, RJ LEE, TJ HEADGORDON, M TI THE ORIGIN OF DIFFERENCES BETWEEN COUPLED-CLUSTER THEORY AND QUADRATIC CONFIGURATION-INTERACTION FOR EXCITED-STATES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MULTICONFIGURATIONAL LINEAR RESPONSE; LEVEL-CORRELATED CALCULATIONS; MOLECULAR ELECTRIC PROPERTIES; POLARIZED BASIS-SETS; EXCITATION-ENERGIES; PERTURBATION-THEORY; QUANTUM-CHEMISTRY; SINGLES; MATRICES; CH+ AB By employing time-dependent linear response theory, the ground state quadratic configuration interaction method with single and double substitutions (QCISD) can be generalized to excited states. However, the excited state QCISD method is numerically inferior to the analogous coupled cluster (CCSD) excited state method, although its formal properties of size consistency and exactness for two electrons are the same. Therefore a modified QCISD method which includes an additional quadratic operator term in the doubles equations, as in the CPMET-C approximation, is investigated. It is shown by calculations on a variety of small molecules to correct substantially the deficiencies of QCISD for excited states, yielding results that are close to full CCSD theory. This CPMET-C based excited state method is size-consistent, but unlike CCSD and QCISD, is not exact for separated pairs of electrons. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP RICO, RJ (reprint author), UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA. RI Lee, Timothy/K-2838-2012 NR 50 TC 38 Z9 38 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 4 PY 1994 VL 218 IS 1-2 BP 139 EP 146 DI 10.1016/0009-2614(93)E1398-Z PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA MV302 UT WOS:A1994MV30200022 ER PT J AU MIN, JB BASS, JM SPRADLEY, LW AF MIN, JB BASS, JM SPRADLEY, LW TI ADAPTIVE FINITE-ELEMENT METHODS FOR 2-DIMENSIONAL PROBLEMS IN COMPUTATIONAL FRACTURE-MECHANICS SO COMPUTERS & STRUCTURES LA English DT Article ID CRACK TIP; STRATEGY; INTEGRALS AB Some recent results obtained using solution-adaptive finite element methods in two-dimensional problems in linear elastic fracture mechanics are presented. The focus is on the basic issue of adaptive finite element methods for validating the new methodology by computing demonstration problems and comparing the stress intensity factors to analytical results. C1 COMPUTAT MECH CO INC,AUSTIN,TX 78752. ADAPT RES CORP,HUNTSVILLE,AL 35805. RP MIN, JB (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 34 TC 4 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD FEB 3 PY 1994 VL 50 IS 3 BP 433 EP 445 DI 10.1016/0045-7949(94)90012-4 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA ND681 UT WOS:A1994ND68100012 ER PT J AU SCHAEFER, BE AF SCHAEFER, BE TI GAMMA-RAY ASTRONOMY - BURSTS OF CONTROVERSY SO NATURE LA English DT Editorial Material RP SCHAEFER, BE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 3 PY 1994 VL 367 IS 6462 BP 411 EP 412 DI 10.1038/367411a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MU679 UT WOS:A1994MU67900029 ER PT J AU ACKERMAN, AS TOON, OB HOBBS, PV AF ACKERMAN, AS TOON, OB HOBBS, PV TI REASSESSING THE DEPENDENCE OF CLOUD CONDENSATION NUCLEUS CONCENTRATION ON FORMATION RATE SO NATURE LA English DT Article ID BOUNDARY-LAYER; MODEL; STRATOCUMULUS AB MARINE stratocumulus clouds play an important role in the Earth's radiation budget. The albedo of these clouds depends on-the cloud droplet size distribution, and therefore, in part, on the number density of cloud condensation nuclei (CCN)1. It has been postulated2 that a positive feedback loop between increased CCN concentrations and decreased drizzle gives rise to a bistable system, in which there are two equilibrium CCN concentration regimes. According to this model, CCN concentration is only weakly dependent on the CCN production rate within the stable regimes, but very strongly dependent on this rate in the transition region between the regimes. If correct, this strong dependence implies that a small increase in the production of CCN over the oceans could drastically increase the planetary albedo. Using a more sophisticated model3 than that used previously, we find no evidence for bistability. However, we find that CCN concentrations are generally strongly dependent on their production rate, so that changes in the latter would influence the Earth's albedo. We also find that the timescale for reducing high CCN concentrations can be as long as several days, which implies that high CCN concentrations can persist in clouds advected to regions of lower CCN production rate. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP ACKERMAN, AS (reprint author), UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195, USA. RI Ackerman, Andrew/D-4433-2012 OI Ackerman, Andrew/0000-0003-0254-6253 NR 10 TC 17 Z9 17 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 3 PY 1994 VL 367 IS 6462 BP 445 EP 447 DI 10.1038/367445a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MU679 UT WOS:A1994MU67900049 ER PT J AU LEONHARDT, T AF LEONHARDT, T TI INTERFERENCE-LAYERING METALLOGRAPHIC TECHNIQUE WINS 1993 JACQUET-LUCAS AWARD SO ADVANCED MATERIALS & PROCESSES LA English DT Article RP LEONHARDT, T (reprint author), NASA,LEWIS RES CTR,MS 49-3,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD FEB PY 1994 VL 145 IS 2 BP 21 EP 22 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA NL890 UT WOS:A1994NL89000002 ER PT J AU NOOR, AK VENNERI, SL AF NOOR, AK VENNERI, SL TI OUTLOOK FOR SPACE TECHNOLOGY SO AEROSPACE AMERICA LA English DT Editorial Material RP NOOR, AK (reprint author), UNIV VIRGINIA,CTR COMPUTAT STRUCT TECHNOL,NASA LANGLEY,CHARLOTTESVILLE,VA, 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 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD FEB PY 1994 VL 32 IS 2 BP 5 EP 5 PG 1 WC Engineering, Aerospace SC Engineering GA MU926 UT WOS:A1994MU92600001 ER PT J AU NOOR, AK VENNERI, SL AF NOOR, AK VENNERI, SL TI PERSPECTIVES ON FUTURE SPACE SYSTEMS SO AEROSPACE AMERICA LA English DT Article RP NOOR, AK (reprint author), UNIV VIRGINIA,NASA LANGLEY,CTR COMPUTAT STRUCT TECHNOL,CHARLOTTESVILLE,VA, 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 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD FEB PY 1994 VL 32 IS 2 BP 14 EP & PG 0 WC Engineering, Aerospace SC Engineering GA MU926 UT WOS:A1994MU92600004 ER PT J AU GALLMAN, JM AF GALLMAN, JM TI PARAMETRIC COMPUTATIONAL STUDY OF ISOLATED BLADE-VORTEX INTERACTION NOISE SO AIAA JOURNAL LA English DT Article ID ROTOR AB A parametric study was performed to quantitatively describe how the vortex core size, the vortex location, and the hover-tip Mach number M(h) affect blade-vortex interaction (BVI) noise. The effects of these parameters on BVI noise are determined using a rotor acoustic prediction program. The acoustic prediction program is based on the well-known Ffowcs Williams and Hawkings equation for acoustic pressure, wherein noncompact monopole terms model rotor blade thickness and distributed dipoles model local blade Surface pressure. The dipole strengths are determined by an unsteady, three-dimensional, full-potential rotor code that models the aerodynamic interactions between a nonlifting rotor and a tip vortex generated by an upstream wing. The acoustic pressures were calculated for several observer positions in regions of intense acoustic radiation for a variety of blade-vortex proximities, orientations, hover-tip Mach numbers, and vortex-core sizes. This study has quantified the sensitivity of BVI noise to the dominant vortex and aerodynamic parameters. The sound pressure level (SPL) falls off as the inverse of the square of the miss distance between the vortex core and the rotor blade when the miss distance is greater than the core radius. Increasing the core radius is not as effective as increasing the miss distance when attempting to reduce BVI noise. As expected, this study shows that SPL decreases with an increase in the obliqueness of interaction. The calculations performed in this work indicate that SPL increases approximately as M(h)(8). These results can be used to guide future research of BVI noise reduction. RP GALLMAN, JM (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 22 TC 6 Z9 6 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1994 VL 32 IS 2 BP 232 EP 238 DI 10.2514/3.11977 PG 7 WC Engineering, Aerospace SC Engineering GA MV016 UT WOS:A1994MV01600002 ER PT J AU ROSEPEHRSSON, SL WYATT, JR BRENNER, KP CARVER, PT BROWN, SW THUROW, AR TRAVIS, JC AF ROSEPEHRSSON, SL WYATT, JR BRENNER, KP CARVER, PT BROWN, SW THUROW, AR TRAVIS, JC TI LABORATORY DEVELOPMENT AND FIELD-EVALUATION OF A PASSIVE SAMPLING DEVICE FOR MONOMETHYLHYDRAZINE IN AMBIENT AIR SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article AB A passive sampling method applicable to personnel and area monitoring was developed for the quantitation of monomethylhydrazine (MMH) in ambient air at sub part-per-million levels. The method involves the use of a black, molded, low-density polyethylene sampler consisting of a diffusion barrier and a citric acid collection medium. It collects samples that can be analyzed by NIOSH colorimetric methods of a coulometric titration procedure. The sampler incorporates a two-millimeter thick diffusion barrier with 144 one-millimeter diameter holes and produces a collection rate for MMH of 27 cm(3)/min. The accuracy of data collected is within 30% of actual values under most conditions. The dosimeter has demonstrated accuracy for sampling periods of 15 min to 66 hours when sampling MMH at the threshold limit value concentration of 200 ppb. Limits of detection are dictated by the specific analytical method. Coulometric titration will detect exposures of 30 ppb-hours. Laboratory tests were conducted in controlled atmospheres to evaluate collection rate, face velocity effects, relative humidity effects, sample stability, reproducibility, linearity, and interference effects of selected chemical vapors. Field tests evaluated performance under typical conditions. Test locations were selected to provide information on probable interferents. A double-blind protocol was used involving industrial hygienists, analytical chemists, and auditors. The data obtained revealed a performance problem not encountered in the laboratory. The cause was identified and the prototype system was modified and retested. Results from the modified sampler show that it is suitable for workplace monitoring applications with two minor interferents: tobacco smoke and intense direct sunlight. C1 USN,RES LAB,WASHINGTON,DC 20375. EG&G,KENNEDY SPACE CTR,FL 32899. WILTECH CORP,KENNEDY SPACE CTR,FL 32899. NASA,KENNEDY SPACE CTR,FL 32899. GEOCENTERS INC,FT WASHINGTON,MD 20744. NR 24 TC 3 Z9 3 U1 1 U2 2 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD FEB PY 1994 VL 55 IS 2 BP 149 EP 162 DI 10.1202/0002-8894(1994)055<0149:LDAFEO>2.0.CO;2 PG 14 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA MV494 UT WOS:A1994MV49400009 ER PT J AU GOYER, M BUI, H CHOU, L EVANS, J KEIL, LC REID, IA AF GOYER, M BUI, H CHOU, L EVANS, J KEIL, LC REID, IA TI EFFECT OF INHIBITION OF NITRIC-OXIDE SYNTHESIS ON VASOPRESSIN SECRETION IN CONSCIOUS RABBITS SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE BLOOD PRESSURE; HEART RATE; N-G-NITRO-L-ARGININE METHYL ESTER; HYPERTONIC SALINE; NITROPRUSSIDE; NITRIC OXIDE SYNTHASE; RENIN SECRETION ID RENIN RELEASE; L-ARGININE; RELAXING FACTOR; NERVOUS-SYSTEM; BLOOD-PRESSURE; SYNTHASE; RAT; ENDOTHELIUM; CELLS; MECHANISMS AB Effect of inhibition of nitric oxide synthesis on vasopressin secretion in conscious rabbits. Am. J. Physiol. 266 (Heart Circ. Physiol. 35): H822-H828, 1994. - NO synthase is present in magnocellular neurons of supraoptic and paraventricular nuclei as well as in the posterior pituitary gland and may participate in control of vasopressin secretion. To test this possibility, experiments were performed in conscious, chronically prepared rabbits to determine the effect of NO synthesis inhibition with N-G-nitro-L-arginine methyl ester hydrochloride (L-NAME) on basal vasopressin secretion and vasopressin responses to increased plasma osmolality (hypertonic saline infusion; P-osm) and decreased blood pressure (nitroprusside infusion). L-NAME infusion (0.5 mg.kg(-1).min(-1) iv) increased mean arterial pressure [MAP; 82.6 +/- 3.4 to 93.0 +/- 3.0 mmHg (P < 0.02)], decreased heart rate [HR; 242 +/- 12 to 209 +/- 9 beats/min (P < 0.02)], decreased plasma renin activity [PRA; 3.1 +/- 0.6 to 2.0 +/- 0.6 ng.ml(-).2 h(-1) (P < 0.001)], and increased plasma vasopressin-concentration [P-AVP; 2.2 +/- 0.3 to 4.5 +/- 1.0 pg/ml (P < 0.05)]. P-osm did not change. Hypertonic saline infusion did not change MAP or HR but decreased PRA [4.3 +/- 0.8 to 0.9 +/- 0.2 ng.ml(-1).2 h(-1) (P < 0.01)], increased P-osm [284 +/- 1 to 305 +/- 2 mosmol/kgH(2)O (P < 0.001)], and increased P-AVP [2.8 +/- 0.3 to 12.7 +/- 2.7 pg/ml (P < 0.01)]. These responses were not significantly altered by pretreatment with L-NAME. Nitroprusside infusion decreased MAP [83.9 +/- 2.2 to 57.4 +/- 2.5 mmHg (P < 0.01)], increased HR [216 +/- 9 to 323 +/- 11 beats/min (P < 0.01)], increased PRA [4.9 +/- 1.1 to 26.7 +/- 2.9 ng.ml(-1) 2 h(-1) (P < 0.01)], and increased P-AVP [2.9 +/- 0.4 to 16.4 +/- 4.9 pg/ml (P < 0.05)]. Again, none of these responses was significantly altered by pretreatment with L-NAME. These results provide evidence that NO participates in regulation of basal vasopressin release but not in vasopressin responses to hyperosmolality and hypotension. C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FU NHLBI NIH HHS [HL-29714] NR 48 TC 40 Z9 40 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0002-9513 J9 AM J PHYSIOL JI Am. J. Physiol. PD FEB PY 1994 VL 266 IS 2 BP H822 EP H828 PN 2 PG 7 WC Physiology SC Physiology GA NA803 UT WOS:A1994NA80300055 PM 7511350 ER PT J AU SCHAEFER, HG HELMREICH, RL AF SCHAEFER, HG HELMREICH, RL TI THE IMPORTANCE OF HUMAN-FACTORS IN THE OPERATING-ROOM SO ANESTHESIOLOGY LA English DT Letter C1 UNIV TEXAS,NASA,AEROSP CREW RES CTR,AUSTIN,TX 78701. RP SCHAEFER, HG (reprint author), UNIV BASEL,KANTONSSPITAL,DEPT ANAESTHESIA,CH-4031 BASEL,SWITZERLAND. NR 5 TC 16 Z9 16 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0003-3022 J9 ANESTHESIOLOGY JI Anesthesiology PD FEB PY 1994 VL 80 IS 2 BP 479 EP 479 DI 10.1097/00000542-199402000-00035 PG 1 WC Anesthesiology SC Anesthesiology GA MX446 UT WOS:A1994MX44600034 PM 8311334 ER PT J AU GOUTORBE, JP LEBEL, T TINGA, A BESSEMOULIN, P BROUWER, J DOLMAN, AJ ENGMAN, ET GASH, JHC HOEPFFNER, M KABAT, P KERR, YH MONTENY, B PRINCE, S SAID, F SELLERS, P WALLACE, JS AF GOUTORBE, JP LEBEL, T TINGA, A BESSEMOULIN, P BROUWER, J DOLMAN, AJ ENGMAN, ET GASH, JHC HOEPFFNER, M KABAT, P KERR, YH MONTENY, B PRINCE, S SAID, F SELLERS, P WALLACE, JS TI HAPEX-SAHEL - A LARGE-SCALE STUDY OF LAND-ATMOSPHERE INTERACTIONS IN THE SEMIARID TROPICS SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID ENERGY BUDGET; SURFACE-LAYER; EVAPORATION; RAINFALL AB The Hydrologic Atmospheric Pilot EXperiment in the Sahel (HAPEX-Sahel) was carried out in Niger, West Africa, during 1991-1992, with an intensive observation period (IOP) in August-October 1992. It aims at improving the parameterization of land surface atmosphere interactions at the Global Circulation Model (GCM) gridbox scale. The experiment combines remote sensing and ground based measurements with hydrological and meteorological modelling to develop aggregation techniques for use in large scale estimates of the hydrological and meteorological behaviour of large areas in the Sahel. The experimental strategy consisted of a period of intensive measurements during the transition period of the rainy to the dry season, backed up by a series of long term measurements in a 1-degrees by 1-degrees square in Niger. Three ''supersites'' were instrumented with a variety of hydrological and (micro) meteeorological equipment to provide detailed information on the surface energy exchange at the local scale. Boundary layer measurements and aircraft measurements were used to provide information at scales of 100-500 km2. All relevant remote sensing images were obtained for this period. This programme of measurements is now being analyzed and an extensive modelling programme is under way to aggregate the information at all scales up to the GCM grid box scale. The experimental strategy and some preliminary results of the IOP are described. C1 ORSTOM, NIAMEY, NIGER. UNIV NIAMEY, NIAMEY, NIGER. Int Crops Res Inst Semi Arid Trop, NIAMEY, NIGER. DEPT SOIL SCI & GEOL, 6700 AA WAGENINGEN, NETHERLANDS. CNRM, F-31057 TOULOUSE, FRANCE. SC-DLO, WINAND STARING CTR, 6700 AC WAGENINGEN, NETHERLANDS. NASA, GODDARD SPACE FLIGHT CTR, GSFC, GREENBELT, MD 20771 USA. ORSTOM, F-34032 MONTPELLIER, FRANCE. LERTS, F-31055 TOULOUSE, FRANCE. UNIV MARYLAND, COLL PK, MD 20742 USA. UPS, AEROL LAB, F-31062 TOULOUSE, FRANCE. INST HYDROL, WALLINGFORD OX10 8BB, OXON, ENGLAND. OI Dolman, A.J./0000-0003-0099-0457 NR 22 TC 231 Z9 244 U1 1 U2 12 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD FEB PY 1994 VL 12 IS 1 BP 53 EP 64 DI 10.1007/s00585-994-0053-0 PG 12 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA MY864 UT WOS:A1994MY86400007 ER PT J AU BISWAS, R STRAWN, RC AF BISWAS, R STRAWN, RC TI A NEW PROCEDURE FOR DYNAMIC ADAPTION OF 3-DIMENSIONAL UNSTRUCTURED GRIDS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID MESHES; SCHEME AB A new procedure is presented for the simultaneous coarsening and refinement of three-dimensional unstructured tetrahedral meshes. This algorithm allows for localized grid adaption that is used to capture aerodynamic flow features such as vortices and shock waves in helicopter flowfield simulations. The mesh-adaption algorithm is implemented in the C programming language and uses a data structure consisting of a series of dynamically-allocated linked lists. These lists allow the mesh connectivity to be rapidly reconstructed when individual mesh points are added and/or deleted. The algorithm allows the mesh to change in an anisotropic manner in order to efficiently resolve directional flow features. The procedure has been successfully implemented on a single processor of a Cray Y-MP computer. Two sample cases are presented involving three-dimensional transonic flow. Computed results show good agreement with conventional structured-grid solutions for the Euler equations. C1 NASA,AMES RES CTR,USA,MOFFETT FIELD,CA 94035. RP BISWAS, R (reprint author), NASA,AMES RES CTR,RIACS,MAIL STOP T27A-1,MOFFETT FIELD,CA 94035, USA. NR 13 TC 27 Z9 27 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD FEB PY 1994 VL 13 IS 6 BP 437 EP 452 DI 10.1016/0168-9274(94)90007-8 PG 16 WC Mathematics, Applied SC Mathematics GA NC694 UT WOS:A1994NC69400001 ER PT J AU HUTCHINGS, JB NEFF, SG WEADOCK, J ROBERTS, L RYNEVELD, S GOWER, AC AF HUTCHINGS, JB NEFF, SG WEADOCK, J ROBERTS, L RYNEVELD, S GOWER, AC TI EVOLUTION OF RADIO GALAXIES TO Z=1 SO ASTRONOMICAL JOURNAL LA English DT Article ID QUASARS AB We report VLA(1) A-configuration studies of a sample of 49 radio galaxies at redshift less than 1. These were selected with no prior knowledge of their morphology and were chosen to match the redshift and luminosity distribution of a previously studied sample of radio-loud quasars. We compare the radio galaxies with the quasar sample and also with a sample of 29 radio galaxies selected for steep spectrum and double-lobe structure. We find that the radio galaxies have more luminous lobes and mostly weaker cores, and there is no population of one-sided sources associated with the galaxies. The radio galaxies' lobe length ratios and lobe power ratios differ from quasars. The overall sizes of the two types of sources are similar, but the radio galaxies have a 3 times larger upper envelope. The distribution of bend angles is similar but the radio galaxies have fewer very bent and straight sources. We discuss these and other comparisons in detail and suggest that while quasars appear to be viewed within a cone and radio galaxies outside it, the two types of source also have intrinsic differences, and both have individual growth and evolution scenarios. This is supported by previously observed differences in optical properties between the two source types. C1 UNIV OXFORD,DEPT ASTROPHYS,OXFORD OX1 3RH,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. UNIV VICTORIA,DEPT PHYS & ASTRON,VICTORIA V8W 3P6,BC,CANADA. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP HUTCHINGS, JB (reprint author), DOMINION ASTROPHYS OBSERV,5071 W SAANICH RD,VICTORIA V8X 4M6,BC,CANADA. NR 11 TC 14 Z9 14 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 1994 VL 107 IS 2 BP 471 EP 479 DI 10.1086/116869 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU144 UT WOS:A1994MU14400006 ER PT J AU SMITH, HA MATTHEWS, JM LEE, KM WILLIAMS, J SILBERMANN, NA BOLTE, M AF SMITH, HA MATTHEWS, JM LEE, KM WILLIAMS, J SILBERMANN, NA BOLTE, M TI AH CAM - A METAL-RICH RR LYRAE STAR WITH THE SHORTEST KNOWN BLAZHKO PERIOD SO ASTRONOMICAL JOURNAL LA English DT Article ID AP-STARS; PHOTOMETRY; FIELD; ABUNDANCES; PROGRAM AB Analysis of 746 new V-band observations of the RR Lyrae star AH Cam obtained during 1989-1992 clearly show that its light curve cannot be described by a single period. In fact, at first glance, the Fourier spectrum of the photometry resembles that of a double-mode pulsator, with peaks at a fundamental period of 0.3686 d and an apparent secondary period of 0.2628 d. Nevertheless, the dual-mode solution is a poor fit to the data. Rather, we believe that AH Cam is a single-mode RR Lyrae star undergoing the Blazhko effect: periodic modulation of the amplitude and shape of its light curve. What was originally taken to be the period of the second mode is instead the 1-cycle/d alias of a modulation sidelobe in the Fourier spectrum. The data are well described by a modulation period of just under 11 d, which is the shortest Blazhko period reported to date in the literature and confirms the earlier suggestion by Goranskii. A low-resolution spectrum of AH Cam indicates that it is relatively metal rich, with Delta S less than or equal to 2. Its high metallicity and short modulation period may provide a critical test of at least one theory for the Blazhko effect. Moskalik's internal resonance model makes specific predictions of the growth rate of the fundamental mode vs fundamental period. AH Cam falls outside the regime of other known Blazhko variables and resonance model predictions, but these are appropriate for metal-poor RR Lyrae stars. If the theory matches the behavior of AH Cam for a metal-rich stellar model, this would bolster the resonance hypothesis. C1 UNIV BRITISH COLUMBIA,DEPT GEOPHYS & ASTRON,VANCOUVER V6T 1Z4,BC,CANADA. UNIV MONTREAL,DEPT PHYS,MONTREAL H3C 3J7,PQ,CANADA. UNIV MONTREAL,OBSERV MT MEGANT,MONTREAL H3C 3J7,PQ,CANADA. UNIV CALIF SANTA CRUZ,UCO LICK OBSERV,NASA,ST SCI,SANTA CRUZ,CA 95064. RP SMITH, HA (reprint author), MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824, USA. NR 39 TC 26 Z9 26 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 1994 VL 107 IS 2 BP 679 EP 691 DI 10.1086/116888 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU144 UT WOS:A1994MU14400025 ER PT J AU GESSNER, SE CARPENTER, KG ROBINSON, RD AF GESSNER, SE CARPENTER, KG ROBINSON, RD TI SEARCH FOR CO ABSORPTION-BANDS IN IUE FAR-ULTRAVIOLET SPECTRA OF COOL STARS SO ASTRONOMICAL JOURNAL LA English DT Article AB Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-UV chromospheric continuum which are superposed strong molecular absorption bands. The absorption bands have been identified by Carpenter et al. [ApJ (1994) (in press)] with the fourth-positive A-X system of CO and are likely formed in the circumstellar shell. Comparison of these GHRS data with archival IUE spectra of alpha Ori indicates that both the continuum and the CO absorption features can be seen with IUE, especially if multiple IUE spectra, reduced with the post-1981 IUESIPS extraction procedure (i.e., with an oversampling slit), are carefully coadded to increase the signal to noise over that obtainable with a single spectrum. We therefore initiated a program, utilizing both new and archival IUE SWP spectra, to survey 15 cool, low-gravity stars, including alpha Ori, for the presence of these two new chromospheric and circumstellar shell diagnostics. We establish positive detections of far-UV stellar continua, well above estimated IUE in-order scattered light levels, in spectra of all of the program stars. However, well-defined CO absorption features are seen only in the alpha Ori spectra, even though spectra of most of the program stars have sufficient signal to noise to allow the detection of features of comparable magnitude to the absorptions seen in alpha Ori. Clearly if CO is present in the circumstellar environments of any of these stars, it is at much lower column densities. C1 NASA,GSFC,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. NASA,GSFC,COMP SCI CORP,GREENBELT,MD 20771. RP GESSNER, SE (reprint author), NASA,GSFC,UNIV SPACE RES ASSOC,CODE 681,GREENBELT,MD 20771, USA. RI Carpenter, Kenneth/D-4740-2012 NR 14 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 1994 VL 107 IS 2 BP 747 EP 750 DI 10.1086/116894 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU144 UT WOS:A1994MU14400031 ER PT J AU ADELMAN, SJ AIKMAN, GCL HAYES, DS PHILIP, AGD SWEIGART, AV AF ADELMAN, SJ AIKMAN, GCL HAYES, DS PHILIP, AGD SWEIGART, AV TI THE HELIUM-TO-HYDROGEN RATIO OF THE UV-BRIGHT STAR BARNARD-29 OF MESSIER-13 SO ASTRONOMY & ASTROPHYSICS LA English DT Note DE STARS, ABUNDANCES; GLOBULAR CLUSTERS, INDIVIDUAL, M13; STARS, INDIVIDUAL, BARNARD 29 (M 13); STARS, AGB; STARS, POPULATION II ID GLOBULAR-CLUSTERS; ABUNDANCE; BRANCH AB Barnard 29 is the most luminous W-bright star of the globular cluster Messier 13. Comparison of its reddening corrected optical region spectrophotometry and IUE low dispersion fluxes and its H gamma profile with the predictions of metal-poor model atmospheres having the metallicity of M 13 indicated T-eff = 20 250 K, log g = 3.15. Observations of He I lambda 4026 taken with echelle spectrograph of the Multi-Mirror telescope using a Reticon detector show that He/H = 0.055 +/- 0.020. Some astrophysical implications of this result are discussed. C1 NATL RES COUNCIL CANADA, DOMINION ASTROPHYS OBSERV, VICTORIA V8X 4M6, BC, CANADA. FAIRBORN OBSERV, TUCSON, AZ 85718 USA. UNION COLL, SCHENECTADY, NY 12308 USA. WESLEYAN UNIV, VAL VLECK OBSERV, MIDDLETOWN, CT 06457 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP ADELMAN, SJ (reprint author), CITADEL, DEPT PHYS, CHARLESTON, SC 29409 USA. NR 18 TC 2 Z9 2 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 1994 VL 282 IS 1 BP 134 EP 136 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MW312 UT WOS:A1994MW31200020 ER PT J AU HUBENY, I HUMMER, DG LANZ, T AF HUBENY, I HUMMER, DG LANZ, T TI NLTE MODEL STELLAR ATMOSPHERES WITH LINE BLANKETING NEAR THE SERIES LIMITS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE LINE FORMATION; RADIATIVE TRANSFER; STARS, ATMOSPHERES, EARLY-TYPE; ULTRAVIOLET, STARS ID APPROXIMATIONS; PROFILES; SPECTRA AB In this paper we study the influence of line-merging regions at the immediate long-wavelength side of a continuum threshold on the computed model atmosphere structure and predicted spectrum. In order to model these regions sufficiently accurately, we have developed two concepts. First, we have extended the occupation probability formalism of Hummer and Mihalas to non-LTE plasmas. Second, in order to treat the very complicated opacity in the line merging region, we have generalized the concept of opacity distribution functions to treat non-LTE situations. Ah Rydberg states are consistently included within this framework, so that no arbitrary cutoff of high (LTE) levels is made. We have calculated several pure hydrogen models atmospheres for two effective temperatures, T-eff = 20000 and 35000 K, and discussed the differences between models calculated with various treatments of the line merging. In particular, we have shown that the error in the predicted profiles of Balmer lines resulting from the neglect of line merging is typically of the order of 3 - 4 %, while the errors in the far-UV portion of the Balmer continuum reaches 15 - 35 %. The errors generally decrease with increasing effective temperature. At the same time, the internal accuracy of the models is shown to be about or below 0.5% for all predicted spectral feautures. We conclude that for interpreting current high-accuracy spectrophotometric observations models including the line merging are necessary, and that the formalism developed in this paper is capable of providing a sufficiently accurate and robust modeling technique. C1 MAX PLANCK INST ASTROPHYS, D-85748 GARCHING, GERMANY. INST ASTRON & ASTROPHYS, D-81679 MUNICH, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP HUBENY, I (reprint author), NASA, GODDARD SPACE FLIGHT CTR, USRA, CODE 681, GREENBELT, MD 20771 USA. NR 21 TC 115 Z9 115 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 1994 VL 282 IS 1 BP 151 EP 167 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MW312 UT WOS:A1994MW31200023 ER PT J AU NOEVER, DA AF NOEVER, DA TI SOLAR GRANULATION AND STATISTICAL CRYSTALLOGRAPHY - A MODELING APPROACH USING SIZE-SHAPE RELATIONS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE SUN, GRANULATION; CONVECTION; METHODS, STATISTICAL ID MESOGRANULATION; EVOLUTION; GRANULES AB The irregular polygonal pattern of solar granulation is analyzed for size-shape relations using statistical crystallography. In contrast to previous work which has assumed perfectly hexagonal patterns for granulation, more realistic accounting of cell (granule) shapes reveals a broader basis for quantitative analysis. Several features emerge as noteworthy: (1) a linear correlation between number of cell-sides and neighboring shapes (called Aboav-Weaire's law); (2) a linear correlation between both average cell area and perimeter and the number of cell-sides (called Lewis's law and a perimeter law, respectively) and (3) a linear correlation between cell area and squared perimeter (called convolution index). This statistical picture of granulation is consistent with a finding of no correlation in cell shapes beyond nearest neighbors. A comparative calculation between existing model predictions taken from luminosity data and the present analysis shows substantial agreements for cell-size distributions. A model for understanding grain lifetimes is proposed which links convective times to cell shape using crystallographic results. RP NOEVER, DA (reprint author), NASA, MARSHALL SPACE FLIGHT CTR, ES-76, HUNTSVILLE, AL 35812 USA. NR 33 TC 5 Z9 5 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 1994 VL 282 IS 1 BP 252 EP 261 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MW312 UT WOS:A1994MW31200033 ER PT J AU GEISS, J GLOECKLER, G MALL, U VONSTEIGER, R GALVIN, AB OGILVIE, KW AF GEISS, J GLOECKLER, G MALL, U VONSTEIGER, R GALVIN, AB OGILVIE, KW TI INTERSTELLAR OXYGEN, NITROGEN AND NEON IN THE HELIOSPHERE SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE SOLAR WIND; INTERPLANETARY MEDIUM; ISM, ABUNDANCES; ISM, ATOMS ID ION COMPOSITION; HYDROGEN; SPECTRA; WIND AB Oxygen, nitrogen and neon pick-up ions of interstellar origin were detected for the first time with the Solar Wind Ion Spectrometer (SWICS) on board Ulysses. The interstellar origin of these ions is established by the following criteria: (a) they are singly charged, (b) they have the broad velocity distributions characteristic of pick-up ions, with an upper limit of twice the solar wind speed, (c) their relative abundance as a function of distance from the sun corresponds to the theoretical expectation, and (d) there is no relation to a planetary or cometary source. The interstellar abundance ratios He+/O+, N+/O+, Ne+/O+ were investigated. At approximately 5.35 AU in the outermost part of Ulysses' trajectory He+/O+ = 175(-50)+70, N+/O+ = 0.13(-0.05)+0.05 and Ne+/O+ = 0.18(-0.07)+0.010 were determined. For the interstellar gas passing through the termination region and entering the heliosphere [He/O]0 = 290(-100)+190, [N/O]0 = 0.13(-0.06)+0.06 and [Ne/O]0 = 0.20(-0.09)+0.12 were obtained from the pick-up ion measurements. Upper limits for the relative abundances of C+ and C were also determined. C1 UNIV MARYLAND, DEPT PHYS, COLL PK, MD 20742 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP GEISS, J (reprint author), UNIV BERN, INST PHYS, SIDLERSTR 5, CH-3000 BERN, SWITZERLAND. RI Von Steiger, Rudolf/F-6822-2011; Galvin, Antoinette/A-6114-2013 OI Von Steiger, Rudolf/0000-0002-3350-0023; NR 39 TC 114 Z9 114 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 1994 VL 282 IS 3 BP 924 EP 933 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ160 UT WOS:A1994MZ16000031 ER PT J AU PETRE, R GEHRELS, N AF PETRE, R GEHRELS, N TI A ROSAT OBSERVATION OF THE TRANSIENT-X-RAY PULSAR GRO-J1008-57 SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE X-RAYS, STARS; STARS, NEUTRON AB We report results of a brief Target of Opportunity observation of the newly discovered transient X-ray pulsar GRO J1008-57 using the ROSAT PSPC. The observation was performed well into the decline of the source outburst as monitored by the BATSE hard X-ray light curve. The PSPC cleanly detected the source, at a 0.1-2.4 keV flux of 2.3 10(-11) erg cm-2 s-1. A position centroid accurate to 10 arc seconds has been determined. The 0.1-2.4 keV spectrum is best characterized by a flat power law with substantial interstellar absorption. The PSPC photon index and column density are consistent with that measured at higher energy by ASCA; there is no evidence for an additional soft component. Light-curve folding reveals a period of 93.4 s, consistent with t hat measured at higher energies; the 0.1-2.4 keV folded light curve shows a high pulsed fraction and a strongly double-peaked pulse profile. The spectral and temporal properties of GRO J1008-57 as observed using the PSPC are entirely consistent with a pulsar orbiting a massive (OB) companion. RP PETRE, R (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Gehrels, Neil/D-2971-2012 NR 11 TC 5 Z9 5 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 1994 VL 282 IS 3 BP L33 EP L36 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MZ160 UT WOS:A1994MZ16000002 ER PT J AU NORTH, P BERTHET, S LANZ, T AF NORTH, P BERTHET, S LANZ, T TI THE NATURE OF THE F-STR LAMBDA-4077 STARS .5. SPECTROSCOPIC DATA SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE STARS, CLASSIFICATION, ABUNDANCES, PECULIAR A, EVOLUTION OF, CLOSE BINARIES; NUCLEOSYNTHESIS ID OSCILLATOR-STRENGTHS; SOLAR ABUNDANCE; SI-II; LINES AB We report first high-resolution spectroscopic observations of 17 stars classified F str lambda 4077 by Bidelman. They are compared to different types of stars, which have been observed at the same time, including 3 CH subgiants, 3 barium stars, 5 lambda Bootis stars, Ap/Am stars, and normal main-sequence stars. The detailed equivalent widths and abundances are given for all measured spectral lines, as well as the mean abundance per species for each object. These data and their significance are described in detail and discussed in an article published in the Main Journal. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP NORTH, P (reprint author), UNIV LAUSANNE,INST ASTRON,CH-1290 CHAVANNES BOIS,SWITZERLAND. NR 28 TC 5 Z9 5 U1 0 U2 0 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD FEB PY 1994 VL 103 IS 2 BP 321 EP 347 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU686 UT WOS:A1994MU68600009 ER PT J AU LUO, XC SCHRAMM, DN AF LUO, XC SCHRAMM, DN TI THE PHENOMENOLOGICAL STATUS OF LATE-TIME PHASE-TRANSITION MODELS AFTER COSMIC BACKGROUND-RADIATION ANISOTROPY MEASUREMENTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; COSMOLOGY, THEORY; LARGE-SCALE STRUCTURE OF UNIVERSE ID LARGE-SCALE STRUCTURE; DIFFERENTIAL MICROWAVE RADIOMETER; COLD DARK MATTER; INFLATIONARY UNIVERSE; PERTURBATIONS; EVOLUTION; GALAXIES; HOT AB Some relatively model-independent results for structure formation via late time phase transitions (LTPT) are discussed. In particular, generic LTPT power spectra are presented. The implication of the recent COBE detection of the cosmic background radiation (CBR) anisotropy at large angular scales (greater than or similar to 7 degrees) and the tight upper limits from small angular scales (similar to 1 degrees) to LTPT models are discussed. Special attention is focused on the observational constraints and possible non-Gaussian signatures of CBR temperature anisotropies from LTPT and other non-Gaussian models. It is shown that while LTPT have been seriously constrained by the recent data, viable models do remain which provide more power on the 100-200 Mpc scales than do more traditional primordial Gaussian density fluctuation models. Tests for such models are presented, including possible anisotropies on angular scales less than 8'. C1 NASA, FERMILAB ASTROPHYS CTR, FERMILAB, BATAVIA, IL 60510 USA. RP UNIV CHICAGO, CTR ASTRON & ASTROPHYS, 5640 S ELLIS AVE, CHICAGO, IL 60637 USA. NR 45 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 393 EP 399 DI 10.1086/173658 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200001 ER PT J AU PROSSER, CF STAUFFER, JR HARTMANN, L SODERBLOM, DR JONES, BF WERNER, MW MCCAUGHREAN, MJ AF PROSSER, CF STAUFFER, JR HARTMANN, L SODERBLOM, DR JONES, BF WERNER, MW MCCAUGHREAN, MJ TI HST PHOTOMETRY OF THE TRAPEZIUM CLUSTER SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, VISUAL; ISM, INDIVIDUAL (ORION NEBULA); OPEN CLUSTERS AND ASSOCIATIONS, INDIVIDUAL (TRAPEZIUM); STARS, PRE-MAIN-SQUENCE ID MAIN-SEQUENCE STARS; ORION NEBULA; M-DWARFS; SYSTEMS; CLOUD; EVOLUTION; HISTORY; COUSINS; BINARY AB We have obtained images of 11 fields in the Trapezium cluster with the Planetary Camera (PC) of the Hubble Space Telescope in order to extend Herbig and Terndrup's (1986) study of this prototype, dense embedded cluster to fainter magnitudes than is possible from the ground. Using these images, we have identified 319 stars within an area of similar to 12 arcmin(2) corresponding roughly to a volume of similar to 0.065 pc(3) assuming the duster is approximately spherically symmetric. Our completeness limits for star identification in V-band and I-band images are V similar or equal to 20 and I-C similar or equal to 19 respectively, corresponding to a mass limit of approximately 0.15 M(.) if the faintest stars have the same average A, as that estimated for the brighter stars in the cluster. We have compared the V versus V-I color-magnitude diagram derived from the HST photometry to new theoretical isochrones. Star formation in the Trapezium appears to be remarkably coeval, with greater than or equal to 80% of the stars having inferred ages less than 1 Myr. Over the somewhat limited mass range of the observations, there is no evidence for ''bimodal'' star formation-the high- and low-mass stars appear to have the same ages. The sharp cores of the HST images and the small angular size of the PC pixels has allowed us to identify 35 new visual binaries in the cluster with separations from similar to 0''.06 (-26 AU) to similar to 1''.0 (similar to-440 AU). For the range of binary separations that we are sensitive to, the observed binary frequency for the Trapezium is essentially identical to that estimated for field low-mass stars by Duquennoy and Mayor (1991). The most straightforward inference from this result is that binaries in this separation are unlikely to be formed by a tidal capture process. We have also identified three stars which have associated compact nebulosity visible in the HST images. One of these star + nebulosity cases was previously identified by O'Dell, Wen, and Hu (1993)-these objects appear to form a class of objects whose circumstellar matter is being ''lit up,'' most likely by theta(1) Ori C, enabling the gas to be observable at both optical and radio wavelengths (Felli et al. 1993a, b). We provide a brief summary of the optical properties of the other radio sources which appear in our PC images. C1 SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. UNIV CALIF SANTA CRUZ, LICK OBSERV, BOARD STUDIES ASTRON & ASTROPHYS, SANTA CRUZ, CA 95064 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. MAX PLANCK INST ASTRON, W-6900 HEIDELBERG, GERMANY. RP SMITHSONIAN ASTROPHYS OBSERV, 60 GARDEN ST, CAMBRIDGE, MA 02138 USA. NR 69 TC 223 Z9 223 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 517 EP 541 DI 10.1086/173668 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200011 ER PT J AU POLLACK, JB HOLLENBACH, D BECKWITH, S SIMONELLI, DP ROUSH, T FONG, W AF POLLACK, JB HOLLENBACH, D BECKWITH, S SIMONELLI, DP ROUSH, T FONG, W TI COMPOSITION AND RADIATIVE PROPERTIES OF GRAINS IN MOLECULAR CLOUDS AND ACCRETION DISKS SO ASTROPHYSICAL JOURNAL LA English DT Review DE ACCRETION, ACCRETION DISKS; DUST, EXTINCTION; ISM, MOLECULES ID DENSE INTERSTELLAR CLOUDS; YOUNG STELLAR OBJECTS; T-TAURI STARS; OPTICAL-PROPERTIES; COMET HALLEY; CIRCUMSTELLAR DISKS; INFRARED-EMISSION; CARBON ABUNDANCE; SOLAR NEBULA; DUST AB We define a model of the composition and abundances of grains and gases in molecular cloud cores and accretion disks around young stars by employing a wide range of astronomical data and theory, the composition of primitive bodies in the solar system, and solar elemental abundances. In the coldest portions of these objects, we propose that the major grain species include olivine ([Fe, Mg]2SiO4), orthopyroxene ([Fe, Mg]SiO3), volatile and refractory organics, water ice, troilite (FeS), and metallic iron. This compositional model differs from almost all previous models of the interstellar medium (ISM) by having organics as the major condensed C species, rather than graphite; by including troilite as a major grain species; and by specifying the mineralogical composition of the condensed silicates. Using a combination of laboratory measurements of optical constants and asymptotic theory, we derive values of the real and imaginary indices of refraction of these grain species over a wavelength range that runs from the vacuum UV to the radio domain. The above information on grain properties is used to estimate the Rosseland mean opacity of the grains and their monochromatic opacity. We find that organics are the largest contributors to the Rosseland mean extinction coefficient at temperatures below their vaporization temperatures (similar or equal to 575 K in molecular cloud cores and 425 K in accretion disks), and that silicates and metallic iron jointly determine the Rosseland mean opacity at higher temperatures. At mid-infrared wavelengths, the computed monochromatic opacities are in approximate accord with the spectral characteristics of ''astronomical silicates.'' At low temperatures (<500 K), the position, strength, width, and contrast of the 10 and 20 mu m silicate vibrational fundamentals can be significantly affected by the opacities of organics and water ice. Strong silicate features are produced only when the average grain size is less than several tens of microns. The spectral index beta of the grain opacity at long wavelengths shows marked variation. In particular, we estimate that it has a value of about 2.5 between 100 and 650 mu m and a value of about 1.5 between 650 mu m and 2.7 mm for submicron- to millimeter-sized grains, in rough agreement with spectral flux measurements of the ISM and some disks around young stars. In the latter spectral region, grain opacity is dominated by silicates, with important contributions also coming from troilite and organics. However, the low values of beta (similar to 0) that appear to characterize a few disks around young stars in the 650 mu m to 2.7 mm region may be the result of significant grain growth that has occurred in these disks (sizes greater than or equal to 10 cm). In a similar vein, existing-far infrared spectral data for the older, Vega-like objects are consistent with grain sizes on the order of hundreds to thousands of microns. We also find that the grain absorption coefficient at 1 mm wavelength lies within a factor of 4 of 5 x 10(-3) cm(2) g-l (of gas and dust) for a wide variety of grain shapes and for grain sizes ranging from submicron to several millimeters. Thus, continuum flux values at 1 mm wavelength can lead to useful estimates of disk masses. C1 MAX PLANCK INST ASTRON,W-6900 HEIDELBERG,GERMANY. CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853. SAN FRANCISCO STATE UNIV FDN INC,SAN FRANCISCO,CA 94132. SYNERNET,FREMONT,CA 94538. RP POLLACK, JB (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. RI Qu, Terrence/C-9586-2012 NR 108 TC 665 Z9 665 U1 1 U2 31 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 615 EP 639 DI 10.1086/173677 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200020 ER PT J AU GEHRZ, RD WOODWARD, CE GREENHOUSE, MA STARRFIELD, S WOODEN, DH WITTEBORN, FC SANDFORD, SA ALLAMANDOLA, LJ BREGMAN, JD KLAPISCH, M AF GEHRZ, RD WOODWARD, CE GREENHOUSE, MA STARRFIELD, S WOODEN, DH WITTEBORN, FC SANDFORD, SA ALLAMANDOLA, LJ BREGMAN, JD KLAPISCH, M TI THE TEMPORAL EVOLUTION OF THE 4-14 MICRON SPECTRUM OF V1974 CYGNI (NOVA CYGNI 1992) SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, STARS; NOVAE, CATACLYSMIC VARIABLES; RADIATION MECHANISMS, NONTHERMAL; STARS, ABUNDANCES; STARS, INDIVIDUAL (NOVA CYGNI 1992) ID HEAVY ELEMENT ABUNDANCES; INFRARED CORONAL LINES; VULPECULAE 1984; NEON NOVA AB We present 4-14 mu m spectra of the ONeMg nova V1974 Cygni (Nova Cygni 1992) obtained during 1992 May on the NASA Kuiper Airborne Observatory (KAO) and from the NASA 1.52 m infrared telescope at Mount Lemmon, Arizona in 1992 October/November with the HIFOGS mid-infrared spectrometer. The spectra at both epochs showed continuum emission from thermal bremstrahlung (free-free radiation) with emission lines from hydrogen and [Ne II], [Ar III], and [Ne VI]. During May, approximate to 80 days after outburst, the dominant emission lines in the mid-infrared spectra were a blend of three hydrogen lines (Pf alpha, Hu beta, H11-7) near 7.5 mu m and [Ne II] at 12.8 mu m. By October (approximate to 160 days later), the hydrogen emission had virtually disappeared, the [Ne II] 12.8 mu m line had weakened considerably, and a pronounced [Ne VI] emission line had appeared at 7.6 mu m. This behavior confirms that V1974 Cyg is similar to the prototypical slow ONeMg ''neon nova,'' Nova QU Vulpeculae (1984 No. 2). The remarkable evolution of the spectrum suggests that the ionization conditions changed drastically between 1992 May and 1992 October. We find that the ejecta of V1974 Cyg were overabundant in neon with respect to silicon by a factor of approximate to 10 relative to the solar photosphere. We present new model calculations of infrared sodium forbidden line emission from [Na III] 7.319 mu m, [Na IV] 9.039 mu m, and [Na IV] 21.29 mu m that can be compared with recent model predictions of sodium synthesis in ONeMg nova outbursts. We conclude that sodium abundances in ONeMg novae can be determined by observations of infrared coronal lines of sodium that are accessible to the Infrared Space Observatory (ISO) and instruments at the NASA IRTF. C1 UNIV WYOMING,DEPT PHYS & ASTRON,WYOMING INFRARED OBSERV,LARAMIE,WY 82071. SMITHSONIAN INST,NATL AIR & SPACE MUSEUM,ASTROPHYS LAB,WASHINGTON,DC 20560. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. USN,RES LAB,ARTEP INC,WASHINGTON,DC 20375. RP GEHRZ, RD (reprint author), UNIV MINNESOTA,SCH PHYS & ASTRON,DEPT ASTRON,116 CHURCH ST SE,MINNEAPOLIS,MN 55455, USA. NR 40 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 762 EP 770 DI 10.1086/173688 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200031 ER PT J AU KONDO, Y MCCLUSKEY, GE SILVIS, JMS POLIDAN, RS MCCLUSKEY, CPS EATON, JA AF KONDO, Y MCCLUSKEY, GE SILVIS, JMS POLIDAN, RS MCCLUSKEY, CPS EATON, JA TI ULTRAVIOLET LIGHT CURVES OF BETA-LYRAE - COMPARISON OF OAO A-2, IUE, AND VOYAGER OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, ECLIPSING; CIRCUMSTELLAR MATTER; STARS, INDIVIDUAL (BETA LYRAE); ULTRAVIOLET, STARS ID SPECTROPHOTOMETRY; STARS AB The six-band ultraviolet light curves of beta Lyrae obtained with the Orbiting Astronomical Observatory A-2 in 1970 exhibited a very unusual behavior. The secondary minimum deepened at shorter wavelength, indicating that one was not observing light variations caused primarily by the eclipses of two stars having a roughly Planckian energy distribution. It was then suggested that the light variations were caused by a viewing angle effect of an optically thick, ellipsoidal circumbinary gas cloud. Since 1978 beta Lyrae has been observed with the International Ultraviolet Explorer (IUE) satellite. We have constructed ultraviolet light curves from the IUE archival data for comparison with the OAO A-2 results. We find that they are in substantial agreement with each other. The Voyager ultraviolet spectrometer was also used to observe this binary during a period covered by IUE observations. The Voyager results agree with those of the two other satellite observatories at wave-lengths longer than about 1350 Angstrom. However, in the wavelength region shorter than the Lyman-alpha line at 1216 Angstrom, the light curves at 1085 and 965 Angstrom show virtually no light variation except an apparent flaring near phase 0.7, which is also in evidence at longer wavelengths. We suggest that the optically thick circumbinary gas cloud, which envelops the two stars completely, assumes a roughly spherical shape when observed at these shorter wavelengths. C1 LEHIGH UNIV,DEPT MATH,BETHLEHEM,PA 18018. CATHOLIC UNIV AMER,DEPT PHYS,WASHINGTON,DC 20064. PENN STATE UNIV,DEPT COMP SCI,FOGLESVILLE,PA 18051. TENNESSEE STATE UNIV,CTR EXCELLENCE INFORMAT SYST,NASHVILLE,TN 37203. RP KONDO, Y (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 684,GREENBELT,MD 20771, USA. NR 18 TC 14 Z9 14 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 787 EP 799 DI 10.1086/173691 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200034 ER PT J AU MARAN, SP ROBINSON, RD SHORE, SN BROSIUS, JW CARPENTER, KG WOODGATE, BE LINSKY, JL BROWN, A BYRNE, PB KUNDU, MR WHITE, S BRANDT, JC SHINE, RA WALTER, FM AF MARAN, SP ROBINSON, RD SHORE, SN BROSIUS, JW CARPENTER, KG WOODGATE, BE LINSKY, JL BROWN, A BYRNE, PB KUNDU, MR WHITE, S BRANDT, JC SHINE, RA WALTER, FM TI OBSERVING STELLAR CORONAE WITH THE GODDARD HIGH-RESOLUTION SPECTROGRAPH .1. THE DME STAR AU MICROSCOPII SO ASTROPHYSICAL JOURNAL LA English DT Article DE METHODS, DATA ANALYSIS; STARS, ACTIVITY; STARS, CORONAE; STARS, INDIVIDUAL (AU MICROSCOPII); STARS, LATE-TYPE; ULTRAVIOLET, STARS ID X-RAY-EMISSION; EXCITATION RATE COEFFICIENTS; SOLAR NEIGHBORHOOD; LINE RATIOS; FLARE STARS; FE-XXI; EXOSAT; TRANSITIONS; ULTRAVIOLET; XII AB We report on an observation of AU Mic taken with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. The data consist of a rapid sequence of spectra covering the wavelength range 1345-1375 Angstrom with a spectral resolution of 10,000. The observations were originally intended to search for spectral variations during flares. No flares were detected during the 3.5 hr of monitoring. A method of reducing the noise while combining the individual spectra in the time series is described which resulted in the elimination of half of the noise while rejecting only a small fraction of the stellar signal. The resultant spectrum was of sufficient quality to allow the detection of emission lines with an integrated flux of 10(-15) ergs cm(-2) s(-1) greater. Lines of C I, O I, O V, Cl I, and Fe XXI were detected. This is the first indisputable detection of the 1354 Angstrom Fe XXI line, formed at T similar to 10(7) K, on a star other than the Sun. The line was well resolved and displayed no significant bulk motions or profile asymmetry. From the upper limit on the observed line width, we derive an upper limit of 38 km s(-1) for the turbulent velocity in the 10(7) K plasma. An upper limit is derived for the flux of the 1349 Angstrom Fe XII line, formed at T similar to 1.3 x 10(6) K. These data are combined with contemporaneous GHRS and IUE data to derive the volume emission measure distribution of AU Mic over the temperature range 10(4)-10(7) K. Models of coronal loops in hydrostatic equilibrium are consistent with the observed volume emission measures of the coronal lines. The fraction of the stellar surface covered by the footpoints of the loops depends upon the loop length and is less than 14% for lengths smaller than the stellar radius. From the upper limit to the estimated width of the Fe XXI line profile we find that we cannot rule out Alfven wave dissipation as a possible contributor to the required quiescent loop heating rate. C1 NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, GREENBELT, MD 20771 USA. OBSERV PARIS, DEPT INTERSTELLAR MATTER & MILLIMETER ASTRON, F-92195 MEUDON, FRANCE. NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX CORP, GREENBELT, MD 20771 USA. UNIV COLORADO, JOINT INST LAB ASTROPHYS, BOULDER, CO 80309 USA. ARMAGH OBSERV, ARMAGH BT61 9DG, NORTH IRELAND. UNIV MARYLAND, DEPT ASTRON, COLL PK, MD 20742 USA. UNIV COLORADO, ATMOSPHER & SPACE PHYS LAB, BOULDER, CO 80309 USA. LOCKHEED PALO ALTO RES LABS, PALO ALTO, CA 94304 USA. SUNY STONY BROOK, DEPT EARTH & SPACE SCI, STONY BROOK, NY 11794 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 680, GREENBELT, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012; Carpenter, Kenneth/D-4740-2012 NR 29 TC 35 Z9 35 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 800 EP 808 DI 10.1086/173692 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200035 ER PT J AU JOHANSSON, SG JOUEIZADEH, A LITZEN, U LARSSON, J PERSSON, A WAHLSTROM, CG SVANBERG, S LECKRONE, DS WAHLGREN, GM AF JOHANSSON, SG JOUEIZADEH, A LITZEN, U LARSSON, J PERSSON, A WAHLSTROM, CG SVANBERG, S LECKRONE, DS WAHLGREN, GM TI COMPARISON OF NEW EXPERIMENTAL AND ASTROPHYSICAL F-VALUES FOR SOME RU-II LINES, OBSERVED IN HST SPECTRA OF CHI-LUPI SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC DATA; LINE, IDENTIFICATION; STARS, ABUNDANCES; STARS, INDIVIDUAL (CHI LUPI); TECHNIQUES, SPECTROSCOPIC; ULTRAVIOLET, STARS ID TRANSITIONS AB We report on experimental absolute oscillator strengths for 18 UV lines of Ru II, obtained by combining laser-induced fluorescence measurements of radiative lifetimes and branching fractions from line intensities in a calibrated Fourier-transform spectrum. HST/GHRS observations of the spectrum of the sharp-lined B star chi Lupi contain six of these lines, for which ''astrophysical'' relative f-values have been determined. The agreement is within 0.10 dex for a Ru abundance of log N(Ru)/N(H) = -7.90, which is 2.3 dex above the solar abundance. C1 LUND UNIV,LUND OBSERV,LUND,SWEDEN. LUND INST TECHNOL,DIV ATOM PHYS,S-22100 LUND,SWEDEN. NASA,GODDARD SPACE FLIGHT CTR,SOLAR PHYS & ASTRON LAB,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,GREENBELT,MD 20771. RP JOHANSSON, SG (reprint author), LUND UNIV,DEPT PHYS,SOLVEGATAN 14,S-22362 LUND,SWEDEN. NR 21 TC 20 Z9 20 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP 809 EP 815 DI 10.1086/173693 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU542 UT WOS:A1994MU54200036 ER PT J AU STOTHERS, RB CHIN, CW AF STOTHERS, RB CHIN, CW TI MORE MISSING STELLAR OPACITY SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; STARS, EVOLUTION; STARS, INTERIORS ID INTERMEDIATE-MASS STARS; TURBULENT CONVECTION; EVOLVED STARS; OPEN CLUSTERS; EVOLUTION; ENERGIES; MODELS; TABLES AB Observational data for Population I stars have shown that blue loops on the H-R diagram form for stellar masses as low as similar to 4 M.. However, current state-of-the-art stellar models, unlike the older ones that were based on smaller opacities, fail to loop out of the red-giant region during core helium burning for masses less than 7 M.. A possible explanation is that the currently used Livermore opacities need to be further increased, by at least 70%, at temperatures characteristic of the base of the outer convection zone, around 1x10(6) K. Indeed, no other suggested remedy seems to yield a blue loop at the lowest observed loop luminosities. RP STOTHERS, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 42 TC 12 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1994 VL 421 IS 2 BP L91 EP L94 DI 10.1086/187195 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MU543 UT WOS:A1994MU54300008 ER PT J AU LOPEZ, RE BAKER, DN AF LOPEZ, RE BAKER, DN TI EVIDENCE FOR PARTICLE-ACCELERATION DURING MAGNETOSPHERIC SUBSTORMS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; EARTH; SOLAR WIND ID AVERAGE PLASMA; MAGNETOTAIL; SHEET; MODEL; RECONNECTION; DISRUPTION; SATELLITE; DYNAMICS; BOUNDARY; SECTOR AB Magnetospheric substorms represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. In this paper we present a brief overview of substorm phenomenology. We then review some of the evidence for particle acceleration in Earth's magnetosphere during substorms. Such in situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems. C1 UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. OI Lopez, Ramon/0000-0001-5881-1365 NR 52 TC 10 Z9 10 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 531 EP 539 DI 10.1086/191871 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400004 ER PT J AU DESCH, MD AF DESCH, MD TI JUPITER RADIO-BURSTS AND PARTICLE-ACCELERATION SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; PLANETS AND SATELLITES, INDIVIDUAL (JUPITER); RADIO CONTINUUM, SOLAR SYSTEM ID ENVIRONMENT; RADIATION; VOYAGER; SOLAR AB Particle acceleration processes are important in understanding many of the Jovian radio and plasma wave emissions. However, except for the high-energy electrons that generate synchrotron emission following inward diffusion from the outer magnetosphere, acceleration processes in Jupiter's magnetosphere and between Jupiter and Io are poorly understood. We discuss very recent observations from the Ulysses spacecraft of two new Jovian radio and plasma wave emissions in which particle acceleration processes are important and have been addressed directly by complementary investigations. First, radio bursts known as quasi-periodic bursts have been observed in close association with a population of highly energetic electrons. Second, a population of much lower energy (keV range) electrons on auroral field lines can be shown to be responsible for the first observation of a Jovian plasma wave emission known as auroral hiss. RP DESCH, MD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 29 TC 18 Z9 18 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 541 EP 546 DI 10.1086/191872 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400005 ER PT J AU BARING, MG ELLISON, DC JONES, FC AF BARING, MG ELLISON, DC JONES, FC TI MONTE-CARLO SIMULATIONS OF PARTICLE-ACCELERATION AT OBLIQUE SHOCKS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; COSMIC RAYS; SHOCK WAVES ID COSMIC-RAYS; MAXIMUM ENERGY; WAVES; ORIGIN AB The fermi shock acceleration mechanism may be responsible for the production of high-energy cosmic rays in a wide variety of environments. Modeling of this phenomenon has largely focused on plane-parallel shocks, and one of the most promising techniques for its study is the Monte Carlo simulation of particle transport in shocked fluid flows. One of the principal problems in shock acceleration theory is the mechanism and efficiency of injection of particles from the thermal gas into the accelerated population. The Monte Carlo technique is ideally suited to addressing the injection problem directly, and previous applications of it to the quasi-parallel Earth bow shock led to very successful modeling of proton and heavy ion spectra, as well as other observed quantities. Recently this technique has been extended to oblique shock geometries, in which the upstream magnetic field makes a significant angle Theta(B1) to the shock normal. In this paper, spectral results 0from test particle Monte Carlo simulations of cosmic-ray acceleration at oblique, nonrelativistic shocks are presented. The results show that low Mach number shocks have injection efficiencies that are relatively insensitive to (though not independent of) the shock obliquity, but that there is a dramatic drop in efficiency for shocks of Mach number 30 or more as the obliquity increases above 15 degrees. Cosmic-ray distributions just upstream of the shock reveal prominent bumps at energies below the thermal peak; these disappear far upstream but might be observable features close to astrophysical shocks. C1 N CAROLINA STATE UNIV,DEPT PHYS,RALEIGH,NC 27695. RP BARING, MG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 24 TC 33 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 547 EP 552 DI 10.1086/191873 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400006 ER PT J AU JONES, FC AF JONES, FC TI A THEORETICAL REVIEW OF DIFFUSIVE SHOCK ACCELERATION SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; MHD; PLASMAS; SHOCK WAVES AB We discuss the fundamental ideas of particle acceleration in plasma shocks with emphasis on those features that are required to produce the ''universal'' power-law spectrum. We compare shock acceleration with the more familiar second-order or stochastic acceleration and see that they are not too different in many respects. We discuss the features of shock acceleration that make it appealing and some of its problems as well. RP JONES, FC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 12 TC 24 Z9 25 U1 5 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 561 EP 565 DI 10.1086/191875 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400008 ER PT J AU ASCHWANDEN, MJ BENZ, AO DENNIS, BR KUNDU, MR AF ASCHWANDEN, MJ BENZ, AO DENNIS, BR KUNDU, MR TI PULSED ACCELERATION IN SOLAR-FLARES SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; SUN, CORONA; SUN, FLARES; SUN, RADIO RADIATION; SUN, X-RAYS, GAMMA RAYS ID 1980 JUNE 7; RADIO PULSATIONS; DECIMETRIC BURSTS; SPECTROMETER; ELECTRON AB We study the nonlinear dynamics of particle acceleration in solar flares by analyzing the time series of various quasi-periodic radio signatures during flares. In particular we present the radio and hard X-ray data of three flares which support the following tentative conclusions: 1. Particle acceleration and injection into magnetic structures occurs intrinsically in a pulsed mode (with a typical period of 1-2s), produced by a single, spatially coherent, nonlinear system, rather than by a stochastic system with many spatially independent components (''statistical flare'' produced by a fragmented primary energy release). 2. The nonlinear (quasi-periodic) mode of pulsed particle acceleration and injection into a coronal loop can be stabilized by phase locking with an MI-ID wave (oscillation) mode, if both periods are close to each other. 3. Pulsed injection of electron beams into a coronal loop may trigger nonlinear relaxational oscillations of wave-particle interactions. This is particularly likely when the limit cycles of both systems are similar. C1 FED INST TECHNOL,INST ASTRON,CH-8092 ZURICH,SWITZERLAND. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP ASCHWANDEN, MJ (reprint author), UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742, USA. RI Dennis, Brian/C-9511-2012 NR 38 TC 29 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 631 EP 638 DI 10.1086/191884 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400017 ER PT J AU REAMES, DV MEYER, JP VONROSENVINGE, TT AF REAMES, DV MEYER, JP VONROSENVINGE, TT TI ENERGETIC-PARTICLE ABUNDANCES IN IMPULSIVE SOLAR-FLARE EVENTS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE SUN, ABUNDANCES; SUN, FLARES; SUN, PARTICLE EMISSION ID CORONAL MASS EJECTIONS; HE-3-RICH EVENTS; PHOTOSPHERIC ABUNDANCES; ELECTRON EVENTS; ACTIVE-REGION; IONIC CHARGE; II BURSTS; ACCELERATION; HE-3; SPECTRUM AB We report on the abundances of energetic particles from impulsive solar flares, including those from a survey of 228 He-3-rich events, with He-3/He-4>0.1, observed by the ISEE 3 spacecraft from 1978 August through 1991 April. The rate of occurrence of these events corresponds to similar to 1000 events yr(-1) on the solar disk at solar maximum. Thus the resonant plasma processes that enhance He-3 and heavy elements are a common occurrence in impulsive solar flares. To supply the observed fluence of He-3 in large events, the acceleration must be highly efficient and the source region must be relatively deep in the atmosphere at a density of more than 10(10) atoms cm(-3). He-3/He-4 may decrease in very large impulsive events because of depletion of He-3 in the source region. The event-to-event variations in He-3/He-4, H/He-4, e/p, and Fe/C are uncorrelated in our event sample. Abundances of the elements show a pattern in which, relative to coronal composition, He-4,C,N, and O have normal abundance ratios, while Ne, Mg, and Si are enhanced by a factor similar to 2.5 and Fe by a factor similar to 7. This pattern suggests that elements are accelerated from a region of the corona with an electron temperature of similar to 3-5 MK, where elements in the first group are fully ionized (Q/A = 0.5), those in the second group have two orbital electrons (Q/A similar to 0.43), and Fe has Q/A similar to 0.28. Ions with the same gyrofrequency absorb waves of that frequency and are similarly accelerated and enhanced. Further stripping may occur after acceleration as the ions begin to interact with the streaming electrons that generated the plasma waves. RP REAMES, DV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 661,GREENBELT,MD 20771, USA. NR 85 TC 200 Z9 203 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 649 EP 667 DI 10.1086/191887 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400020 ER PT J AU BATCHELOR, D AF BATCHELOR, D TI ANOTHER CLUE ABOUT PARTICLE-ACCELERATION IN IMPULSIVE HARD X-RAY/MICROWAVE BURSTS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; SUN, RADIO RADIATION; X-RAYS, BURSTS ID SOLAR-FLARES; YOHKOH AB In a sample of impulsive bursts with rise times less than 30 s, a correlation between burst rise times and the frequency of maximum microwave emission has been found. The implications for source structure and dynamics are discussed in this paper. Previously evidence was found that such bursts are caused by some propagating disturbance such as a shock wave or thermal conduction front. Combining that evidence with the microwave and hard X-ray spectral information suggests that the most rapid bursts are emitted from the most compact and intensely magnetized sources. The most rapid bursts also exhibited the hardest X-ray spectra, as published previously. These facts are important clues to understanding the physical process responsible for impulsive bursts. A model for the bursts is suggested, based on the observations and inferences described. RP BATCHELOR, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SPACE PHYS DATA FACIL,CODE 632,GREENBELT,MD 20771, USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 697 EP 700 DI 10.1086/191892 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400025 ER PT J AU HARDING, AK AF HARDING, AK TI GAMMA-RAY BURST THEORY - BACK TO THE DRAWING BOARD SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; GAMMA RAYS, BURSTS ID NEUTRON-STAR BINARIES; GALACTIC HALO; CYCLOTRON; SPECTRA; LINES; SCATTERING; ABSORPTION; EVOLUTION; PULSARS; MODEL AB Gamma-ray bursts have always been intriguing sources to study in terms of particle acceleration, but not since their discovery two decades ago has the theory of these objects been in such turmoil. Prior to the launch of Compton Gamma-Ray Observatory and observations by BATSE, there was strong evidence pointing to magnetized Galactic neutron stars as the sources of gamma-ray bursts. However, since BATSE the observational picture has changed dramatically, requiring much more distant and possibly cosmological sources. I review the history of gamms-ray burst theory from the era of growing consensus for nearyby neutron stars to the recent explosion of halo and cosmological models and the impact of the present confusion on the particle acceleration problem. RP HARDING, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Harding, Alice/D-3160-2012 NR 58 TC 10 Z9 10 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 863 EP 868 DI 10.1086/191916 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400049 ER PT J AU BARING, MG AF BARING, MG TI GAMMA-RAY BURST SPECTRAL BREAKS AND SOURCE BEAMING SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE GAMMA-RAYS, BURSTS; RADIATION MECHANISMS, NONTHERMAL ID PAIR PRODUCTION; FIREBALLS AB The principal discovery of the Compton Gamma-Ray Observatory (GRO) concerning gamma-ray bursts is that these sources are isotropic but with a comparative deficiency of fainter sources, suggesting that they are probably cosmological in origin. If they are at such large distances from Earth then they are extremely luminous and compact. A consequence of this is that two-photon pair production attenuation of the gamma-ray continuum cannot be avoided unless the source radiation is substantially beamed. Most sources do not display gamma-ray turnovers although a few GRB detected by GRO exhibit distinct spectral breaks in the MeV range. A derivation of the relationship defining of the degree of beaming in burst sources with spectral breaks due to gamma-gamma attenuation, as a function of source spectral index and break energy, is presented. It is found that sources at distances of similar to 1 Gpc must typically be beamed with bulk Lorentz factors of around 10(3)-10(4), indicating powerful bulk acceleration in bursts, although these Lorentz factors are reduced markedly for steep source spectra. Since the source spectra are not strongly Comptonized, such beaming will blueshift the gamma-gamma attenuation breaks to energies much higher than 1 MeV; an absolute lower bound to the source bulk Lorentz factor is determined from this additional constraint. This blueshifting suggests that those sources with MeV breaks may not be cosmological, or that their breaks are produced by a mechanism that dominates gamma-gamma attenuation at these energies. RP BARING, MG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 23 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 899 EP 903 DI 10.1086/191922 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400055 ER PT J AU FICHTEL, CE AF FICHTEL, CE TI HIGH-ENERGY GAMMA-RAY OBSERVATIONS OF ACTIVE GALAXIES SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article; Proceedings Paper CT International-Astronomical-Union Colloquium 142 CY JAN 11-15, 1993 CL COLL PK, MD SP INT ASTRON UNION DE ACCELERATION OF PARTICLES; GALAXIES, ACTIVE; GAMMA RAYS, OBSERVATIONS; QUASARS, GENERAL ID RADIO-SOURCES; RADIATION AB During the period from 1992 May to early 1992 November, the Energetic Gamma-Ray Experiment Telescope ( EGRET) on board the Compton Gamma Ray Observatory obtained high-energy gamma-ray data for most of the sky. A total of 18 active galaxies have been seen with high certainty, and it is expected that more will be found in the data when a more thorough analysis is complete. All of those that have been seen are radio-loud quasars or BL Lacertae objects; most have already been identified as blazars. No Seyfert galaxies have been found thus far. If the spectra are represented as a power law in energy, spectral slopes ranging from approximately -1.7 to -2.4 are found. A wide range of z-values exists in the observed sample, eight having values in excess of 1.0. Time variations have been seen, with the timescale for a significant change being as short as days in at least one case. These results imply the existence of very large numbers of relativistic particles, probably close to the central object. Although a large extrapolation is required, their existence also suggests that these active galactic nuclei may be the source of the extragalactic cosmic rays. RP FICHTEL, CE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 29 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1994 VL 90 IS 2 BP 917 EP 922 DI 10.1086/191925 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MT954 UT WOS:A1994MT95400058 ER PT J AU PEREZ, MR GRADY, CA THE, PS AF PEREZ, MR GRADY, CA THE, PS TI THE EVIDENCE FOR CLUMPY ACCRETION IN THE HERBIG AE STAR HR-5999 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID BETA-PICTORIS; SPECTRAL VARIABILITY; CIRCUMSTELLAR GAS; AE/BE STARS; LINES; ORIONIS; SYSTEM AB Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR 5999 (HD 144668) covering 1978-1992 has revealed dramatic changes in the Mg II h and k (2795.5, 2802.7 angstrom) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Lyalpha, O I and CIV emission lines, which are correlated with the UV excess luminosity. We also observe variability in the spectral type inferred from the UV spectral energy distribution, ranging from A5 IV-III in high state to A7 III in the low state. The trend of earlier inferred spectral type with decreasing wavelength and with increasing UV continuum flux has previously been noted as a signature of accretion disks in lower mass pre-main sequence stars (PMS) and in systems undergoing FU Orionis-type outbursts. Our data represent the first detection of similar phenomena in an intermediate mass (M greater-than-or-equal-to 2 M.) PMS star. Recent IUE spectra show gas accreting toward the star with velocities as high as +300 km s-1, much as is seen toward beta Pic, and suggest that we also view this system through the debris disk. The absence of UV lines with the rotational broadening expected given the optical data (A7 IV, v sin i = 180 +/- 20 km s-1) for this system also suggests that most of the UV light originates in the disk, even in the low continuum state. The dramatic variability in the column density of accreting gas, consistent with clumpy accretion, such as has been observed toward beta Pic, is a hallmark of accretion onto young stars, and is not restricted to the clearing phase, since detectable amounts of accretion are present for stars with 0.5 < t(age) < 2.8 Myr. The implications for models of beta Pic and similar systems are briefly discussed. C1 APPL RES CORP,LANDOVER,MD. UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,AMSTERDAM,NETHERLANDS. RP PEREZ, MR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CSC,ASTRON PROGRAMS,IUE OBSERV,GREENBELT,MD 20771, USA. NR 31 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 115 EP 124 DI 10.1007/BF00984515 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200015 ER PT J AU TEREBEY, S CHANDLER, CJ ANDRE, P AF TEREBEY, S CHANDLER, CJ ANDRE, P TI MILLIMETER CONTINUUM MEASUREMENTS OF CIRCUMSTELLAR DUST AROUND VERY YOUNG LOW-MASS STARS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID DENSE CORES; STELLAR OBJECTS; DARK CLOUDS; T-TAURI; DISKS AB We investigate the question of disk formation during the protostar phase. We build on the results of Keene and Masson (1990) whose analysis of L1551 showed the millimeter continuum emission comes from both an unresolved circumstellar component, i.e., a disk and an extended cloud core. We model the dust continuum emission from the cloud core and show how it is important at 1.3 mm but negligible at 2.7 mm. Combining new 2.7 mm Owens Valley interferometer data of IRAS-Dense cores with data from the literature we conclude that massive disks are also seen toward a number of other sources. However, 1.3 mm data from the IRAM 30 m telescope for a larger sample shows that massive disks are relatively rare, occurring around perhaps 5% of young embedded stars. This implies that either massive disks occur briefly during the embedded phase or that relatively few young stars form massive disks. At 1.3 mm the median flux of IRAS-Dense cores is nearly the same as T Tauri stars in the sample of Beckwith et al. (1990). We conclude that the typical disk mass during the embedded phase is nearly the same or less than the typical disk mass during the T Tauri phase. C1 CALTECH,OWENS VALLEY RADIO OBSERV,PASADENA,CA 91125. CTR ETUD SACLAY,SERV ASTROPHYS,GIF SUR YVETTE,FRANCE. RP TEREBEY, S (reprint author), JET PROP LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91109, USA. NR 13 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 191 EP 195 DI 10.1007/BF00984523 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200023 ER PT J AU LESTRADE, JF JONES, DL PRESTON, RA PHILLIPS, RB AF LESTRADE, JF JONES, DL PRESTON, RA PHILLIPS, RB TI HIGH-PRECISION VLBI ASTROMETRIC OBSERVATIONS OF RADIO-EMITTING STARS FOR DETECTION OF EXTRA-SOLAR PLANETS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID SYSTEM AB The displacement of a radio-emitting star around the barycenter of a possible planetary system can be measured by astrometric very long baseline interferometry (VLBI) observations. We have observed the radio-emitting star sigma2 CrB at 8 epochs over 5 years by VLBI and fitted its 5 astrometric parameters to the observed coordinates. The post-fit coordinate residuals have an rms scatter of 0.22 milliarcseconds and show no systematic behavior. We use this result to set a limit on the presence of planets around sigma2 CrB and conclude that our present VLBI astrometric precision corresponds to the threshold to detect a Jupiter-like planet around this star. We also discuss the astrometric monitoring program of 11 radio-emitting stars that we are conducting for the Hipparcos space mission and its possible contribution to a long-term planet search program. C1 MIT,HAYSTACK OBSERV,WESTFORD,MA. RP LESTRADE, JF (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 17 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 251 EP 260 DI 10.1007/BF00984529 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200029 ER PT J AU BORUCKI, W KOCH, D AF BORUCKI, W KOCH, D TI MULTIPLEX APPROACH TO THE PHOTOMETRIC DETECTION OF PLANETS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID TIME AB If the hypothesis is correct that most solar-like stars have planetary systems and have planets in inner orbits, then approximately 1% of these stars should have planets with orbital planes close enough to our line of sight to show transits. To get a statistically significant estimate of the fraction of stars that have planets in inner orbits, it is necessary to monitor thousands of stars continuously for a period of several years. To accomplish this requires the use of a multi-channel photometer system. We present here several multi-channel methods that have been used for ground-based observations and a concept for applying multi-channel photometry to the detection of numerous Earth-sized planets. RP BORUCKI, W (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 293 EP 298 DI 10.1007/BF00984533 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200033 ER PT J AU HALE, A DOYLE, LR AF HALE, A DOYLE, LR TI THE PHOTOMETRIC-METHOD OF EXTRASOLAR PLANET DETECTION REVISITED SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID SYSTEMS; ORIENTATION; SEARCH AB We investigate the geometry concerning the photometric method of extrasolar planet detection, i.e., the detection of dimunition of a parent star's brightness during a planetary transit. Under the assumption that planetary orbital inclinations can be defined by a Gaussian with a sigma of 10-degrees centered on the parent star's equatorial plane, Monte Carlo simulations suggest that for a given star observed at an inclination of exactly 90-degrees, the probability of at least one Earth-sized or larger planet being suitably placed for transits is approximately 4%. This probability drops to 3% for a star observed at an inclination of 80-degrees, and is still approximately 0.5% for a star observed at an inclination of 60'. If one can select 100 stars with a pre-determined inclination > 800, the probability of at least one planet being suitably configured for transits is 95%. The majority of transit events are due to planets in small-a orbits similar to the Earth and Venus; thus, the photometric method in principle is the method best suited for the detection of Earthlike planets. The photometric method also allows for testing whether or not planets can exist within binary systems. This can be done by selecting binary systems observed at high orbital inclinations, both eclipsing binaries and wider visual binaries. For a ''real-world'' example, we look at the alpha Centauri system (i = 79.2-degrees). If we assume that the equatorial planes of both components coincide with the system's orbital plane, Monte Carlo simulations suggest that the probability of at least one planet (of either component) being suitably configured for transits is approximately 8%. In conclusion, we present a non-exhaustive list of solar-type stars, both single and within binary systems, which exhibit a high equatorial inclination. These objects may be considered as preliminary candidates for planetary searches via the photometric method. C1 NASA,AMES RES CTR,SETI INST,MOFFETT FIELD,CA 94035. RP HALE, A (reprint author), SW INST SPACE RES,ALAMOGORDO,NM, USA. NR 19 TC 19 Z9 20 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 335 EP 348 DI 10.1007/BF00984537 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200037 ER PT J AU KORECHOFF, RP DINER, DJ TUBBS, EF GAISER, SL AF KORECHOFF, RP DINER, DJ TUBBS, EF GAISER, SL TI EXTRASOLAR PLANET DETECTION SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID INTERFEROMETER; SYSTEMS AB This paper discusses the concept of extrasolar planet detection using a large-aperture infrared imaging telescope. Coronagraphic stellar apodization techniques are less efficient at infrared wavelengths compared to the visible, as a result of practical limitations on aperture dimensions, thus necessitating additional starlight suppression to make planet detection feasible in this spectral domain. We have been investigating the use of rotational shearing interferometry to provide up to three orders of magnitude of starlight suppression over broad spectral bandwidths. We present a theoretical analysis of the system performance requirements needed to make this a viable instrument for planet detection, including specifications on the interferometer design and telescope aperture characteristics. The concept of using rotational shearing interferometry as a wavefront error detector, thus providing a signal that can be used to adaptively correct the wavefront, will be discussed. We also present the status of laboratory studies of on-axis source suppression using a recently constructed rotational shearing interferometer that currently operates in the visible. RP KORECHOFF, RP (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 14 TC 2 Z9 2 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 369 EP 383 DI 10.1007/BF00984540 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200040 ER PT J AU COLAVITA, MM SHAO, M AF COLAVITA, MM SHAO, M TI INDIRECT PLANET DETECTION WITH GROUND-BASED LONG-BASE-LINE INTERFEROMETRY SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID III STELLAR INTERFEROMETER; ATMOSPHERIC LIMITATIONS; ANGLE ASTROMETRY AB Narrow-angle astrometry with long-baseline infrared interferometers can provide extremely high accuracies as required for indirect planet detection. Narrow-angle astrometric interferometry exploits the properties of atmospheric turbulence over fields smaller than the interferometer baseline divided by the atmospheric scale height. For such fields, accuracy is linear with star separation, and nearly inversely proportional to baseline length. To exploit these properties, the interferometer observes a relatively bright (< 13 mag(K)) target in the near infrared at 2.2 mum, and uses phase referencing to find a reference star within the 2.2-mum isoplanatic patch. With this technique faint references can be found for most targets. With baselines > 100 m, which also minimize photon-noise errors, and with careful control of systematic errors by using laser metrology, accuracies of tens of microarcseconds/square-root hour should be possible. RP COLAVITA, MM (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 9 TC 6 Z9 8 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 385 EP 390 DI 10.1007/BF00984541 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200041 ER PT J AU JONES, DL AF JONES, DL TI DIRECT IMAGING OF PLANETARY SYSTEMS WITH A GROUND-BASED RADIO TELESCOPE ARRAY SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB AB The National Radio Astronomy Observatory's proposed Millimeter Array (MMA) will bring unprecedented sensitivity, angular resolution, and image dynamic range to the millimeter wavelength region of the spectrum. An obvious question is whether such an instrument could be used to detect planets orbiting nearby stars. The techniques of aperture synthesis imaging developed for centimeter wavelength radio arrays are capable of producing images whose dynamic ranges greatly exceed the brightness ratio of a solar-type star and a Jupiter-like planet at sub-millimeter or millimeter wavelengths. The angular resolution required to separate a star and planet at a few pc distance can be obtained with baselines of several km. The greatest challenge is sensitivity. At the highest possible observing frequencies (approximately 300 GHz for typical high, dry sites, and approximately 900 GHz from the Antarctic plateau), the proposed MMA will be unable to detect the thermal emission from a Jupiter-like planet a few pc away. An upgraded MMA operating near 300 GHz with twice the currently proposed number of antennas, a 20% fractional bandwidth, and improved receivers could detect Jupiter at 4 pc in a few months. Building such an array on the Antarctic plateau and operating at almost-equal-to 900 GHz would allow Jupiter at 4 pc to be detected in approximately one day of observing time. RP JONES, DL (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 9 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 391 EP 394 DI 10.1007/BF00984542 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200042 ER PT J AU CRUIKSHANK, DP WERNER, MW BACKMAN, DE AF CRUIKSHANK, DP WERNER, MW BACKMAN, DE TI SIRTF - CAPABILITIES FOR THE STUDY OF PLANETARY SYSTEMS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB ID SEARCH AB The Space Infrared Telescope Facility, to be launched into a near-Earth heliocentric orbit in the year 2001, will open broad new vistas for the study, at infrared wavelengths, of the objects in the Solar System and planetary systems around other stars. This paper focuses on the study of Kuiper-belt comets and circumstellar planetary debris disks. C1 JET PROP LAB,PASADENA,CA 91109. FRANKLIN & MARSHALL COLL,DEPT PHYS & ASTRON,LANCASTER,PA 17604. RP CRUIKSHANK, DP (reprint author), NASA,AMES RES CTR,ASTROPHYS BRANCH,MOFFETT FIELD,CA 94035, USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 407 EP 415 DI 10.1007/BF00984544 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200044 ER PT J AU THRONSON, HA HAWARDEN, TG BALLY, J RAPP, D STERN, SA AF THRONSON, HA HAWARDEN, TG BALLY, J RAPP, D STERN, SA TI THE EDISON-INFRARED-SPACE-OBSERVATORY AND THE STUDY OF EXTRA-SOLAR PLANETARY MATERIAL SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB AB Edison is a proposed large-aperture, radiatively-cooled space observatory planned to operate at wavelengths between 2 and 130 mum or longer. Current estimates for the telescope allow an aperture of 1.7 m which will achieve a final equilibrium temperature of about 30 K, although use of cryocoolers may permit temperatures below 20 K. Edison will be a powerful tool to investigate our Solar System, as well as planetary material around distant stars. At near- and mid-infrared wavelengths, where planetary material emits most of its radiation, Edison will be the most sensitive photometric and spectroscopic observatory under current consideration by the space agencies. With its large aperture, Edison will be able both to resolve the structure in nearby circumstellar ''Vega disks'' and to discriminate faint IR emission in the crowded environment of the galactic plane. With its long lifetime, Edison will allow extensive follow-up observations and increase the likelihood of catching transient events. We propose Edison as a precursor to elements of a future space-based IR interferometer. C1 JOINT ASTRON CTR,EDINBURGH,SCOTLAND. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. UNIV COLORADO,BOULDER,CO 80309. JET PROP LAB,PASADENA,CA 91109. SW RES INST,SAN ANTONIO,TX 78284. RP THRONSON, HA (reprint author), WYOMING INFRARED OBSERV,EDINBURGH,SCOTLAND. RI Thronson, Harley/E-3382-2012 NR 9 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 423 EP 431 DI 10.1007/BF00984546 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200046 ER PT J AU PRAVDO, SH TERRILE, RJ FTACLAS, C GATEWOOD, GD LEVY, EH AF PRAVDO, SH TERRILE, RJ FTACLAS, C GATEWOOD, GD LEVY, EH TI THE ASTROMETRIC IMAGING TELESCOPE - DETECTION OF PLANETARY SYSTEMS WITH IMAGING AND ASTROMETRY SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB AB The Astrometric Imaging Telescope (AIT) is a proposed spaceborne observatory whose primary goal is the detection and study of extra-solar planetary systems. It contains two instruments that use complementary techniques to address the goal. The first instrument, the Coronagraphic Imager, takes direct images of nearby stars and Jupiter-size planets. It uses a telescope with scattering-compensated optics and a high-efficiency coronagraph to separate reflected planet light from the central star light. Planet detections take hours; confirmations occur in months. With a program duration of about 2 years, about 50 stars are observed. The second instrument, the Astrometric Photometer, shares the same telescope and focal plane. It uses a Ronchi ruling that is translated across the focal plane to simultaneously measure the positions of each target star and about 25 reference stars with sufficient accuracy to detect Uranus-mass planets around hundreds of stars. Enough stars of several spectral types are observed to obtain a statistically significant measurement of the prevalence of planetary systems. This observing program takes about 10 years to complete. The combination of both instruments in a single telescope system results from a number of innovative solutions that are described in this paper. C1 HUGHES DANBURY OPT SYST INC,DANBURY,CT. UNIV PITTSBURGH,ALLEGHENY OBSERV,PITTSBURGH,PA 15260. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP PRAVDO, SH (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 433 EP 440 DI 10.1007/BF00984547 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200047 ER PT J AU FTACLAS, C NONNENMACHER, AL TERRILE, RJ PRAVDO, SH GATEWOOD, GD LEVY, EH AF FTACLAS, C NONNENMACHER, AL TERRILE, RJ PRAVDO, SH GATEWOOD, GD LEVY, EH TI THE CIRCUMSTELLAR IMAGER - DIRECT-DETECTION OF EXTRA-SOLAR PLANETARY SYSTEMS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB AB The Astrometric Imaging Telescope (AIT) is designed to probe the circumstellar environment by both direct imaging and indirect astrometric measurements. The Circumstellar Imager (CI) is a coronagraphic camera and is the direct imaging component of the AIT. The CI is designed to obtain high-sensitivity images of the circumstellar region. It provides crucial non-inferential information relating to the frequency, origin, and evolution of planetary systems and all forms of circumstellar matter. Such imaging is usually limited by the scattered and diffracted light halos of the star itself, which are greatly suppressed in the CI by mating a novel high-efficiency coronagraph with a phase-compensated optical system. For faint point sources in the circumstellar region, the CI will have a sensitivity in excess of 5 magnitudes fainter than the as-designed Hubble Space Telescope (HST). Laboratory data are shown for the coronagraph, which, in a diffraction-limited environment, is capable of suppressing the stellar diffraction sidelobes by several orders of magnitude without significant sacrifice of field of view. In order to realize the high rejection levels inherent in the coronagraph design, it is necessary to limit scatter in the optical systems, imposing a mid-spatial frequency figure error requirement an order of magnitude smaller than that of the HST. Experimental data directed toward meeting this requirement are also shown. C1 JET PROP LAB,PASADENA,CA 91109. UNIV PITTSBURGH,ALLEGHENY OBSERV,PITTSBURGH,PA 15260. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP FTACLAS, C (reprint author), HUGHES DANBURY OPT SYST INC,DANBURY,CT, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 441 EP 452 DI 10.1007/BF00984548 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200048 ER PT J AU SHAKLAN, S PRAVDO, S GATEWOOD, G FTACLAS, C AF SHAKLAN, S PRAVDO, S GATEWOOD, G FTACLAS, C TI MODELING OF A SPACE-BASED RONCHI RULING EXPERIMENT FOR HIGH-PRECISION ASTROMETRY SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 1st International Conference on Planetary Systems: Formation, Evolution, and Detection CY DEC 08-10, 1992 CL JET PROPULS LAB, PASADENA, CA SP NASA HO JET PROPULS LAB AB An end-to-end modelling program for an astrometric telescope employing a Ronchi ruling has been developed. The program models the aberrated images formed anywhere in the field-of-view. It then determines apparent centroids by simulating the motion of a Ronchi ruling across the field. Photo-electron statistics are included. A 6-term plate-constant model is used to determine the apparent motion of a target star within a reference frame as the object is re-observed through both ideal and perturbed optics. The modelling code is accurate at the submicroarcsecond level. C1 ALLEGHENY OBSERV,PITTSBURGH,PA. HUGHES DANBURY OPT SYST INC,DANBURY,CT. RP SHAKLAN, S (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP 453 EP 463 DI 10.1007/BF00984549 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200049 ER PT J AU ALLEN, L AF ALLEN, L TI PLANETARY SYSTEMS - FORMATION, EVOLUTION, AND DETECTION - PROCEEDINGS OF THE 1ST INTERNATIONAL-CONFERENCE, HELD IN PASADENA, CALIFORNIA ON DECEMBER 8-10, 1992 - FOREWORD SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Editorial Material RP ALLEN, L (reprint author), JET PROP LAB,1040 S ARROYO BLVD,PASADENA,CA 91109, USA. NR 0 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP R9 EP R9 DI 10.1007/BF00984501 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200001 ER PT J AU BURKE, BF AF BURKE, BF TI PLANETARY SYSTEMS - FORMATION, EVOLUTION, AND DETECTION - INTRODUCTION SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Editorial Material RP BURKE, BF (reprint author), JET PROP LAB,MS 301-490,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD FEB PY 1994 VL 212 IS 1-2 BP R11 EP R12 DI 10.1007/BF00984502 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA NT282 UT WOS:A1994NT28200002 ER PT J AU HERBUTE, S OLIVER, J DAVET, J VISO, M BALLARD, RW GHARIB, C GABRION, J AF HERBUTE, S OLIVER, J DAVET, J VISO, M BALLARD, RW GHARIB, C GABRION, J TI ANP BINDING-SITES ARE INCREASED IN CHOROID-PLEXUS OF SLS-1 RATS AFTER 9 DAYS OF SPACEFLIGHT SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID ATRIAL-NATRIURETIC-PEPTIDE; CEREBROSPINAL-FLUID PRESSURE; HYPERTENSIVE RATS; RECEPTORS; BRAIN; AUTORADIOGRAPHY; HYDROCEPHALUS AB Specific alpha-rat 28-aminoacid atrial natriuretic peptide [ANP(99-126)] (rANP) binding sites in choroid plexus and meningia of rats flown for 9 days on the mission STS-40 (SLS-1) carried on the space shuttle Columbia in June 1991 were analyzed after incubation of brain sections with I-125-rANP and autoradiography, using computer-assisted microdensitometric image analysis. The number of I-125-rANP binding sites (expressed by Bmax values) in the choroid plexus of lateral and third ventricles of these rats was significantly increased (X1.5-2.5 times), as compared with that found in ground control rats. No differences in the binding affinity (deducible from Kd values) were observed at the level of these structures. The choroid plexus from the fourth ventricle of the same rats displayed no changes in the binding capacity or affinity after the spaceflight. Meningia from the rats flown in space did not demonstrate any significant modifications of the number of I-125-rANP binding sites, but displayed a significant increase in Kd values, which suggested a reduced affinity of the meningeal ANP receptors during a 9-d spaceflight. The possibility that atrial natriuretic peptide may be involved in the regulation of fluid and electrolyte fluxes in the brain, during adaptation to microgravity, through modified expression of specific high affinity receptors, mainly in choroid plexus from forebrain or in meningia, must be considered. C1 CTR NATL ETUD SPATIALES,PARIS,FRANCE. NASA,AMES RES CTR,SPACE LIFE SCI PAYLOAD OFF,MOFFETT FIELD,CA 94035. RP HERBUTE, S (reprint author), UNIV MONTPELLIER 2,CNRS,URA 530,PL E BATAILLON,F-35095 MONTPELLIER 5,FRANCE. NR 21 TC 11 Z9 11 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD FEB PY 1994 VL 65 IS 2 BP 134 EP 138 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA MW503 UT WOS:A1994MW50300007 PM 8161323 ER PT J AU WELCH, RB AF WELCH, RB TI THE DISSECTION OF INTERSENSORY BIAS - WEIGHTING FOR RADEAU SO CAHIERS DE PSYCHOLOGIE COGNITIVE-CURRENT PSYCHOLOGY OF COGNITION LA English DT Note RP WELCH, RB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 23 TC 9 Z9 9 U1 0 U2 1 PU ADRSC-ASSOC DIFFUSION RECHERCHES SCIENCES COGNITIVES PI MARSEILLE CEDEX 13 PA IBHOP, TRAVERSE CHARLES SUSINI, 13388 MARSEILLE CEDEX 13, FRANCE SN 0249-9185 J9 CAH PSYCHOL COGN JI Cah. Psychol. Cogn.-Curr. Psychol. Cogn. PD FEB PY 1994 VL 13 IS 1 BP 117 EP 123 PG 7 WC Psychology, Experimental SC Psychology GA NK746 UT WOS:A1994NK74600012 PM 11540552 ER PT J AU DALTON, AS AF DALTON, AS TI MICROINSTRUMENTS FOR SPACE MISSIONS SO CHEMTECH LA English DT Article RP DALTON, AS (reprint author), JET PROP LAB,SPACECRAFT SYST ENGN SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD FEB PY 1994 VL 24 IS 2 BP 36 EP 40 PG 5 WC Chemistry, Applied SC Chemistry GA MY673 UT WOS:A1994MY67300010 ER PT J AU GOLDEN, DC MING, DW BOWEN, LH MORRIS, RV LAUER, HV AF GOLDEN, DC MING, DW BOWEN, LH MORRIS, RV LAUER, HV TI ACIDIFIED OXALATE AND DITHIONITE SOLUBILITY AND COLOR OF SYNTHETIC, PARTIALLY OXIDIZED AL-MAGNETITES AND THEIR THERMAL-OXIDATION PRODUCTS SO CLAYS AND CLAY MINERALS LA English DT Article DE ALUMINUM SUBSTITUTION; ELECTRON MICROSCOPY; HEMATITE; MAGHEMITE; MAGNETITE; OXIDATION; SOLUBILITY ID IRON-OXIDES; FERRIHYDRITES; HEMATITE; ALUMINUM; SPECTRA; SOILS AB Submicron-sized (approximately 3-60 nm) powders of Al-substituted magnetite were synthesized in the laboratory by precipitation methods by mixing appropriate molar volumes FeCl2, FeCl3 and AlCl3 solutions and precipitating with 20% NH4OH. Precipitates were dialyzed for 48 hr to remove excess salts and then freeze-dried. The nominal Al mole fractions [Al(s) = Al/(Al + Fe)] in the initial precipitate ranged from 0.001 to 0.42. Portions of the resulting powders were heated sequentially in air at 400-degrees and 500-degrees-C. Powders were examined using X-rav diffraction (XRD), transmission electron microscopy (TEM), and visible and near-IR reflectance spectroscopy. Solubilities were determined in ammonium oxalate (pH = 3) and dithionite-citrate-bicarbonate (DCB) solutions. As determined by XRD, the mineralogy of precipitated powder samples was predominantly magnetite. Powders having Al(s) > 0.20 contained minor goethite and a poorly crystalline iron oxide phase (ferrihydrite?), and powders having Al(s) > 0.25 also contained gibbsite. The color of the magnetites was black throughout the range of Al-substitution. Powders heated to 400-degrees-C were reddish brown; Munsell colors ranged from 5R 2/2 to 10R 3/4 for Al(s) from 0.1-41.5%, respectively. By XRD, these powders were maghemite, but hematite was also detected by Mossbauer spectroscopy. XRD and Mossbauer data indicate powders heated to 500-degrees-C are hematite; their Munsell colors are not noticeably different from the corresponding 400-degrees-C samples. Mean crystallite dimensions (MCDs) of the magnetite powders increase with the Al mole fraction from approximately 10 nm for Al(s) = 0.00 1% to a maximum value of 35 nm for Al(s) = 0.15 and decrease slightly with further increasing Al substitution. Heating magnetite powders to 400-degrees-C did not change the MCDs significantly. Heating to 500-degrees-C resulted in hematites having MCDs larger than those for corresponding precursor magnetites for Al(s) < 0.10. The opposite is true for hematites derived from magnetites having Al(s) > 0.10. For hematite powders with Al(s) > 0.05, MCD decreased with increasing Al-substitution. Solubilities of powders in oxalate solutions were independent of Al content and decreased in the order unheated samples (mostly magnetite) > 400-degrees-C-heated samples (maghemite + hematite) >500-degrees-C-heated samples (hematite). All powders dissolved completely in DCB. The low crystallinity of the magnetite powders and the presence of ferrous iron are responsible for their relatively high solubility in oxalate solutions. C1 N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. LOCKHEED ESC,HOUSTON,TX 77058. RP GOLDEN, DC (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 21 TC 5 Z9 5 U1 1 U2 5 PU CLAY MINERALS SOCIETY PI BOULDER PA PO BOX 4416, BOULDER, CO 80306 SN 0009-8604 J9 CLAY CLAY MINER JI Clay Clay Min. PD FEB PY 1994 VL 42 IS 1 BP 53 EP 62 DI 10.1346/CCMN.1994.0420107 PG 10 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA NH880 UT WOS:A1994NH88000007 ER PT J AU SAWYER, C GRYMES, RA AF SAWYER, C GRYMES, RA TI HUMAN DERMAL FIBROBLASTS ORIENT IN RESPONSE TO APPLIED STRETCH SO CLINICAL RESEARCH LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,BIONET CORP,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SLACK INC PI THOROFARE PA 6900 GROVE RD, THOROFARE, NJ 08086 SN 0009-9279 J9 CLIN RES JI Clin. Res. PD FEB PY 1994 VL 42 IS 1 BP A41 EP A41 PG 1 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA MR214 UT WOS:A1994MR21400217 ER PT J AU BERKE, L HATEZ, W PAO, YH AF BERKE, L HATEZ, W PAO, YH TI AUTOMATED DEVELOPMENT OF NEURAL-NET ANALYSIS AND OPTIMIZATION EXPERT SO COMPUTING SYSTEMS IN ENGINEERING LA English DT Article ID NETWORKS AB The envisioned role of an Automated Intelligent Designer Associate (AIDA) is to help the creative designer to conveniently explore his design concepts. Such a capability should be able to learn and improve its performance by accumulating experience. As a step towards an AIDA capability, Artificial Neural Nets are shown to capture structural analysis and optimization domain expertise and provide quick estimates of structural behavior and of optimum designs within the domain of their training. In the approach discussed here, an automated procedure generates random instances of structural analysis or optimization ''experiences'' within a design domain, extracts training patterns, constructs and trains an appropriate network architecture. The final product is a trained neural net that can estimate analysis or optimization results for given design conditions within the domain of its ''expertise''. C1 AI WARE INC,CLEVELAND,OH. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP BERKE, L (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-0521 J9 COMPUT SYST ENG JI Comput. Syst. Eng. PD FEB PY 1994 VL 5 IS 1 BP 55 EP 63 DI 10.1016/0956-0521(94)90037-X PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary SC Computer Science; Engineering GA PD376 UT WOS:A1994PD37600005 ER PT J AU HOOKER, MW WISE, SA SELIM, R CATON, W BUONCRISTIANI, AM AF HOOKER, MW WISE, SA SELIM, R CATON, W BUONCRISTIANI, AM TI HIGH T-C LEADS FOR REMOTE-SENSING APPLICATIONS SO CRYOGENICS LA English DT Article DE HIGH T-C SUPERCONDUCTIVITY; SPACE CRYOGENICS; REMOTE SENSING ID O FILMS; SUPERCONDUCTIVITY AB Several NASA programmes designed to monitor the earth's atmosphere from space utilize infrared detectors which operate at or below 4.2 K for optimum performance. At present, the detectors are maintained at cryogenic temperatures by a stored volume of liquid helium. These detectors must be electrically linked to amplification electronics and data storage instruments maintained at 80 K. The electrical connections over the temperature gradient account for approximate to 20% of the total heat load on the Dewar for some systems, accelerating the boil-off of liquid helium cryogen and reducing the operational lifetime of the space-borne instruments. The recent discovery of high temperature superconductors has provided an opportunity to develop electrically conductive, thermally insulating links to bridge this thermal gradient. This paper describes the modelling of the thermal transport properties of thick film, high T-c electrical bridges across a 4.2-80 K temperature gradient and the impact of such devices on a spaceborne remote sensing system. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. CHRISTOPHER NEWPORT UNIV,DEPT PHYS & COMP SCI,NEWPORT NEWS,VA 23606. RP HOOKER, MW (reprint author), SCI & TECHNOL CORP,HAMPTON,VA 23666, USA. NR 23 TC 3 Z9 3 U1 0 U2 1 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD FEB PY 1994 VL 34 IS 2 BP 119 EP 122 DI 10.1016/0011-2275(94)90034-5 PG 4 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA MT358 UT WOS:A1994MT35800004 ER PT J AU CLARK, P JOERG, S DEHON, R AF CLARK, P JOERG, S DEHON, R TI SEARCHING THE SINUS-AMORIS - USING PROFILES OF GEOLOGICAL UNITS, IMPACT AND VOLCANIC FEATURES TO CHARACTERIZE A MAJOR TERRANE INTERFACE ON THE MOON SO EARTH MOON AND PLANETS LA English DT Article ID LUNAR AB Geochemical profiles of surface units, impact, and volcanic features are studied in detail to determine the underlying structure in an area of extensive mare/highland interface, Sinus Amoris. This study region includes and surrounds the northeastern embayment of Mare Tranquillitatis. The concentrations of two major rock-forming elements (Mg and Al), which were derived from the Apollo 15 orbital geochemical measurements, were used in this study. Mapped units and deposits associated with craters in the northwestern part of the region tend to have correlated low Mg and Al concentrations, indicating the presence of KREEP-enriched basalt. Found along the northeastern rim of Tranquillitatis were areas with correlated high Mg and Al concentration, indicating the presence of troctolite. Distinctive west/east and north/south trends were observed in the concentrations of Mg and Al, and, by implication, in the distribution of major rock components on the surface. Evidence for a systematic geochemical transition in highland or basin-forming units may be observed here in the form of distinctive differences in chemistry in otherwise similar units in the western and eastern portions of the study region. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NE LOUISIANA UNIV,MONROE,LA 71209. RP CLARK, P (reprint author), ALBRIGHT COLL,READING,PA, USA. NR 19 TC 4 Z9 4 U1 0 U2 2 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 PD FEB PY 1994 VL 64 IS 2 BP 165 EP 185 DI 10.1007/BF00604488 PG 21 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA NZ923 UT WOS:A1994NZ92300008 ER PT J AU POPE, KO REJMANKOVA, E SAVAGE, HM ARREDONDOJIMENEZ, JI RODRIGUEZ, MH ROBERTS, DR AF POPE, KO REJMANKOVA, E SAVAGE, HM ARREDONDOJIMENEZ, JI RODRIGUEZ, MH ROBERTS, DR TI REMOTE-SENSING OF TROPICAL WETLANDS FOR MALARIA CONTROL IN CHIAPAS, MEXICO SO ECOLOGICAL APPLICATIONS LA English DT Article DE CHIAPAS, MEXICO; LANDSAT THEMATIC MAPPER (TM); MALARIA; MOSQUITO ECOLOGY; REMOTE SENSING; TROPICAL WETLANDS ID ANOPHELES-ALBIMANUS; LARVAL HABITATS; PSEUDOPUNCTIPENNIS AB Malaria, transmitted by anopheline mosquitoes, remains a serious health problem in the tropics. Most malaria eradication efforts focus on control of anopheline vectors. These efforts include the NASA Di-Mod project, whose current goal is to integrate remote sensing, geographic information systems (GIS), and field research to predict anopheline mosquito population dynamics in the Pacific coastal plain of Chiapas, Mexico. Field studies demonstrate that high larval production of Anopheles albimanus, the principal malaria vector in the plain, can be linked to a small number of larval habitat-types, determined by larval sampling and cluster analysis of wetlands in the coastal plain. Analysis of wet and dry season Landsat Thematic Mapper (TM) satellite imagery identified 16 land cover units within an 185-km(2) study area in the coastal zone. A hierarchical approach was used to link the larval habitat-types with the larger land cover units and make predictions of potential and actual low, medium, and high anopheline production. The TM-based map and GIS techniques were then used to predict differences in anopheline production at two villages, La Victoria and Efrain Gutierrez. La Victoria was predicted to have much higher Anopheles albimanus production, based upon a 2-10 times greater extent of medium- and high-producing land cover units in its vicinity. This difference between villages was independently supported by sampling (with light traps) of adults, which were 5-10 times more abundant in La Victoria. C1 UNIV CALIF DAVIS,DIV ENVIRONM STUDIES,DAVIS,CA 95616. CTR DIS CONTROL,DIV VECTOR BORNE INFECT DIS,MED ENTOMOL & ECOL BRANCH,FT COLLINS,CO 80522. CTR INVEST PALUDISMO,TAPACHULA 30700,CHIAPAS,MEXICO. UNIFORMED SERV UNIV HLTH SCI,DEPT PREVENT MED & BIOMETR,BETHESDA,MD 20814. TGS TECHNOL INC,NASA,AMES OPERAT,MOFFETT FIELD,CA. STANFORD UNIV,STANFORD,CA 94305. RP POPE, KO (reprint author), GEO ECO ARC RES,2222 FOOTHILL BLVD,SUITE E-272,LA CANADA FLINTRIDGE,CA 91011, USA. NR 25 TC 59 Z9 64 U1 2 U2 10 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD FEB PY 1994 VL 4 IS 1 BP 81 EP 90 DI 10.2307/1942117 PG 10 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA MU605 UT WOS:A1994MU60500009 PM 11539870 ER PT J AU SOGARD, SM OLLA, BL AF SOGARD, SM OLLA, BL TI THE POTENTIAL FOR INTRACOHORT CANNIBALISM IN AGE-0 WALLEYE POLLOCK, THERAGRA-CHALCOGRAMMA, AS DETERMINED UNDER LABORATORY CONDITIONS SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE FISH BEHAVIOR; PISCIVORY; GADIDAE ID EASTERN BERING SEA; SIZE; BASS; SURVIVAL; PREDATOR; ECOLOGY; LARVAE; GROWTH; PIKE AB In laboratory experiments, we tested the capability of larger age-0 walleye pollock to consume smaller members of their cohort. In separate aquaria, 81 pairs of juveniles covering a wide range of size differences (total lengths differing by 12 to 61 mm) were held and monitored over a 4 day period. Complete consumption, in which a smaller fish was swallowed whole by a larger fish, occurred 11% of the time. In 36% of the pairs, attacks by the larger fish resulted in mortality of the smaller fish. The mouth width:body depth ratio between the larger and smaller fish of a pair differed significantly depending on whether the smaller fish survived, was killed but not consumed, or was ingested whole by the larger fish. Cannibalistic individuals could consume fish close to the maximum size physically possible under gape limitation; at this size the length of the cannibal was approximately 1.7 times the length of the prey. Length-frequency distributions of age-0 pollock in field concentrations suggested that, at least in some geographical areas, potential cannibals and prey commonly co-occur. Unsuccessful predatory attacks by larger individuals may have additional detrimental effects on smaller pollock in natural populations. RP SOGARD, SM (reprint author), NATL MARINE FISHERIES SERV,HATFIELD MARINE SCI CTR,ALASKA FISHERIES SCI CTR,NEWPORT,OR 97365, USA. NR 23 TC 28 Z9 28 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD FEB PY 1994 VL 39 IS 2 BP 183 EP 190 DI 10.1007/BF00004936 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA MX384 UT WOS:A1994MX38400010 ER PT J AU HANSEN, DA DENNIS, RL EBEL, A HANNA, SR KAYE, J THUILLIER, R AF HANSEN, DA DENNIS, RL EBEL, A HANNA, SR KAYE, J THUILLIER, R TI THE QUEST FOR AN ADVANCED REGIONAL AIR-QUALITY MODEL SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ACID DEPOSITION MODEL C1 US EPA,RES TRIANGLE PK,NC 27711. UNIV COLOGNE,W-5000 COLOGNE 1,GERMANY. SIGMA RES CORP,CONCORD,MA 01742. NASA HEADQUARTERS,WASHINGTON,DC 20546. PACIFIC GAS & ELECT CO,SAN RAMON,CA 94583. RP HANSEN, DA (reprint author), ELECT POWER RES INST,PALO ALTO,CA 94304, USA. NR 23 TC 5 Z9 5 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB PY 1994 VL 28 IS 2 BP A71 EP A77 DI 10.1021/es00051a001 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA MV347 UT WOS:A1994MV34700004 ER PT J AU DONNELL, BL AF DONNELL, BL TI OBJECT RULE INTEGRATION IN CLIPS SO EXPERT SYSTEMS LA English DT Article AB This paper gives a brief overview of the C Language Integrated Production System (CLIPS) with a focus on the object-oriented features. The advantages of an object data representation over the traditional working memory element (WME), i.e. facts, are discussed and the implementation of the Rete inference algorithm in CLIPS is presented in detail. A few methods for achieving pattern-matching on objects with the current inference engine are given and, finally, the paper examines the modifications necessary to the Rete algorithm to allow direct object pattern-matching. RP DONNELL, BL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,INFORMAT SYST DIRECTORATE,SOFTWARE TECHNOL BRANCH,HOUSTON,TX 77058, USA. NR 19 TC 3 Z9 3 U1 0 U2 0 PU LEARNED INFORMATION LTD PI OXFORD PA WOODSIDE, HINKSEY HILL, OXFORD, ENGLAND OX1 5AU SN 0266-4720 J9 EXPERT SYST JI Expert Syst. PD FEB PY 1994 VL 11 IS 1 BP 29 EP 45 DI 10.1111/j.1468-0394.1994.tb00315.x PG 17 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA NX485 UT WOS:A1994NX48500004 ER PT J AU OBERDORSTER, G WHITE, R RABIN, R CLARKSON, T IRONS, R GARDNER, D TAYLOR, GR SONNENFELD, G THOMAS, R AF OBERDORSTER, G WHITE, R RABIN, R CLARKSON, T IRONS, R GARDNER, D TAYLOR, GR SONNENFELD, G THOMAS, R TI SPACE EXPLORATION AND TOXICOLOGY - A NEW FRONTIER SO FUNDAMENTAL AND APPLIED TOXICOLOGY LA English DT Article C1 NASA,DIV SPACE LIFE SCI,WASHINGTON,DC 20546. CTR SPACE & ADV TECHNOL,FAIRFAX,VA 22031. CU,HLTH SCI CTR,DENVER,CO 80262. MANTECH ENVIRONM TECHNOL INC,RES TRIANGLE PK,NC 27709. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NAS,WASHINGTON,DC 20546. UNIV LOUISVILLE,LOUISVILLE,KY 40208. RP OBERDORSTER, G (reprint author), UNIV ROCHESTER,DEPT ENVIRONM MED,ROCHESTER,NY 14642, USA. NR 8 TC 0 Z9 1 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0272-0590 J9 FUND APPL TOXICOL JI Fundam. Appl. Toxicol. PD FEB PY 1994 VL 22 IS 2 BP 161 EP 171 DI 10.1006/faat.1994.1020 PG 11 WC Toxicology SC Toxicology GA MZ249 UT WOS:A1994MZ24900001 PM 7911766 ER PT J AU LINDSTROM, DJ WENTWORTH, SJ MARTINEZ, RR MCKAY, DS AF LINDSTROM, DJ WENTWORTH, SJ MARTINEZ, RR MCKAY, DS TI TRACE-ELEMENT IDENTIFICATION OF 3 CHEMICALLY DISTINCT VERY-LOW TITANIUM (VLT) BASALT GLASSES FROM APOLLO-17 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID LUNAR AB Lunar basaltic samples of VLT (Very Low Titanium) composition occur primarily as small glass fragments in the regolith at the Apollo 17 landing site. Electron microprobe analyses of glasses from the double drive tube 79001/2 (90-150 mum size fraction of soils from mean depths of 0.8-16.8 cm) indicate that 34 of 90 (38%) are of VLT composition. A subset of twenty glasses was removed from the thin sections using a micro-coring device and analyzed using special micro-INAA techniques to obtain major and trace element abundances. On the basis of the results, we delineate three distinct groups which have been named for their relative amounts of Co: HICo, MECo, and LOCo Apollo 17 VL Fs. The most magnesian HICo basalt glasses (4 of 34, or about 12% of the VLT glasses) are probably pristine pyroclastics. Soil breccias 79135 and 70295 apparently contain only this type of VI-T glass. The medium-Co MECo glasses (6 of 34, 18%) strongly resemble the largest sample of VLT composition, the olivine vitrophyre 78526, as well as all three of the Apollo 17 VLT lithic fragments that have been analyzed for trace elements. The LOCo VLT glasses (23 of 34, 68%) are more enigmatic. Trace element concentrations require that these three VLT compositions cannot be related by simple igneous processes. The distribution of the three types provides important information on the sequence of events that produced the regolith at the Apollo 17 site. C1 LOCKHEED ESC,C23,HOUSTON,TX 77058. RP LINDSTROM, DJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058, USA. NR 26 TC 10 Z9 10 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 FEB PY 1994 VL 58 IS 4 BP 1367 EP 1375 DI 10.1016/0016-7037(94)90388-3 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA NA419 UT WOS:A1994NA41900012 ER PT J AU JONES, JH DRAKE, MJ AF JONES, JH DRAKE, MJ TI RUBIDIUM AND CESIUM IN THE EARTH AND MOON - REPLY SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Note ID MANTLE; EVOLUTION C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP JONES, JH (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058, USA. NR 5 TC 4 Z9 4 U1 0 U2 1 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 FEB PY 1994 VL 58 IS 4 BP 1387 EP 1387 DI 10.1016/0016-7037(94)90392-1 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA NA419 UT WOS:A1994NA41900016 ER EF