FN Thomson Reuters Web of Science™ VR 1.0 PT B AU ROSS, MD CHIMENTO, T DOSHAY, D CHENG, R AF ROSS, MD CHIMENTO, T DOSHAY, D CHENG, R BE COHEN, B TOMKO, DL GUEDRY, F TI COMPUTER-ASSISTED 3-DIMENSIONAL RECONSTRUCTION AND SIMULATIONS OF VESTIBULAR MACULAR NEURAL CONNECTIVITIES SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP ROSS, MD (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 8 Z9 9 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 75 EP 91 DI 10.1111/j.1749-6632.1992.tb25201.x PG 17 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00006 PM 1350896 ER PT B AU TOMKO, DL PAIGE, GD AF TOMKO, DL PAIGE, GD BE COHEN, B TOMKO, DL GUEDRY, F TI LINEAR VESTIBULOOCULAR REFLEX DURING MOTION ALONG AXES BETWEEN NASOOCCIPITAL AND INTERAURAL SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP TOMKO, DL (reprint author), NASA,AMES RES CTR,DIV LIFE SCI,VESTIBULAR RES FACIL,MOFFETT FIELD,CA 94035, USA. NR 0 TC 23 Z9 23 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 233 EP 241 DI 10.1111/j.1749-6632.1992.tb25212.x PG 9 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00017 PM 1599146 ER PT B AU COHEN, MM AF COHEN, MM BE COHEN, B TOMKO, DL GUEDRY, F TI PERCEPTION AND ACTION IN ALTERED GRAVITY SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP COHEN, MM (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 354 EP 362 DI 10.1111/j.1749-6632.1992.tb25221.x PG 9 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00026 PM 1599155 ER PT B AU BLOOMBERG, JJ RESCHKE, MF HUEBNER, WP PETERS, BT AF BLOOMBERG, JJ RESCHKE, MF HUEBNER, WP PETERS, BT BE COHEN, B TOMKO, DL GUEDRY, F TI THE EFFECTS OF TARGET DISTANCE ON EYE AND HEAD MOVEMENT DURING LOCOMOTION SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP BLOOMBERG, JJ (reprint author), NASA,AMES RES CTR,SPACE BIOMED RES INST,MAIL CODE SD5,MOFFETT FIELD,CA 94035, USA. NR 0 TC 26 Z9 26 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 699 EP 707 PG 9 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00052 ER PT B AU NEMIRE, K COHEN, MM AF NEMIRE, K COHEN, MM BE COHEN, B TOMKO, DL GUEDRY, F TI OPTICAL AND SOMATESTHETIC BIASES OF POSTURAL ORIENTATION IN THE PITCH DIMENSION SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP NEMIRE, K (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 871 EP 873 DI 10.1111/j.1749-6632.1992.tb25279.x PG 3 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00084 PM 1599205 ER PT B AU DAUNTON, NG CHRISTENSEN, CA AF DAUNTON, NG CHRISTENSEN, CA BE COHEN, B TOMKO, DL GUEDRY, F TI ANTAGONISTIC OTOLITH-VISUAL UNITS IN CAT VESTIBULAR NUCLEI SO SENSING AND CONTROLLING MOTION: VESTIBULAR AND SENSORIMOTOR FUNCTION SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT CONF ON SENSING AND CONTROLLING MOTION : VESTIBULAR AND SENSORIMOTOR FUNCTION CY JUL 07-11, 1991 CL PALO ALTO, CA SP NEW YORK ACAD SCI, NASA, NIDOCD, USN, OFF NAVAL RES RP DAUNTON, NG (reprint author), NASA,DIV LIFE SCI,MAIL STOP 261-3,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 2 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-734-4 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1992 VL 656 BP 924 EP 926 DI 10.1111/j.1749-6632.1992.tb25296.x PG 3 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA BW41U UT WOS:A1992BW41U00101 PM 1599223 ER PT J AU GILBERT, JR MOLER, C SCHREIBER, R AF GILBERT, JR MOLER, C SCHREIBER, R TI SPARSE MATRICES IN MATLAB - DESIGN AND IMPLEMENTATION SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE MATLAB; MATHEMATICAL SOFTWARE; MATRIX COMPUTATION; SPARSE MATRIX ALGORITHMS ID GAUSSIAN-ELIMINATION; FACTORIZATION AB The matrix computation language and environment MATLAB is extended to include sparse matrix storage and operations. The only change to the outward appearance of the MATLAB language is a pair of commands to create full or sparse matrices. Nearly all the operations of MATLAB now apply equally to full or sparse matrices, without any explicit action by the user. The sparse data structure represents a matrix in space proportional to the number of nonzero entries, and most of the operations compute sparse results in time proportional to the number of arithmetic operations on nonzeros. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. MATHWORKS,MENLO PK,CA 94025. RP GILBERT, JR (reprint author), XEROX CORP,PALO ALTO RES CTR,3333 COYOTE HILL RD,PALO ALTO,CA 94304, USA. NR 28 TC 198 Z9 202 U1 0 U2 10 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD JAN PY 1992 VL 13 IS 1 BP 333 EP 356 DI 10.1137/0613024 PG 24 WC Mathematics, Applied SC Mathematics GA HC846 UT WOS:A1992HC84600024 ER PT J AU FREUND, RW AF FREUND, RW TI CONJUGATE GRADIENT-TYPE METHODS FOR LINEAR-SYSTEMS WITH COMPLEX SYMMETRICAL COEFFICIENT MATRICES SO SIAM JOURNAL ON SCIENTIFIC AND STATISTICAL COMPUTING LA English DT Article DE COMPLEX SYMMETRICAL MATRICES; NONSYMMETRIC LANCZOS ALGORITHM; BICONJUGATE GRADIENTS; MINIMAL RESIDUAL PROPERTY ID LANCZOS-ALGORITHM; EQUATIONS AB Conjugate gradient-type methods for the solution of large sparse linear systems Ax = b with complex symmetric coefficient matrices A = A(T) are considered. Such linear systems arise in important applications, such as the numerical solution of the complex Helmholtz equation. Furthermore, most complex non-Hermitian linear systems which occur in practice are actually complex symmetric. Conjugate gradient-type iterations which are based on a variant of the nonsymmetric Lanczos algorithm for complex symmetric matrices are investigated. In particular, a new approach with iterates defined by a quasi-minimal residual property is proposed. The resulting algorithm presents several advantages over the standard biconjugate gradient method. Some remarks are also included on the obvious approach to general complex linear systems by solving equivalent real linear systems for the real and imaginary parts of x. Finally, numerical experiments for linear systems arising from the complex Helmholtz equation are reported. C1 UNIV WURZBURG,INST ANGEW MATH & STAT,W-8700 WURZBURG,GERMANY. RP FREUND, RW (reprint author), NASA,AMES RES CTR,ADV COMP SCI RES INST,MAIL STOP ELLIS ST,MOFFETT FIELD,CA 94035, USA. NR 43 TC 245 Z9 248 U1 2 U2 5 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0196-5204 J9 SIAM J SCI STAT COMP PD JAN PY 1992 VL 13 IS 1 BP 425 EP 448 DI 10.1137/0913023 PG 24 WC Mathematics, Applied SC Mathematics GA HB904 UT WOS:A1992HB90400024 ER PT J AU HATHAWAY, DH AF HATHAWAY, DH TI SPHERICAL HARMONIC-ANALYSIS OF STEADY PHOTOSPHERIC FLOWS .2. SO SOLAR PHYSICS LA English DT Article ID SOLAR ROTATION MEASUREMENTS; MERIDIONAL FLOW; VELOCITY-FIELDS; MOUNT-WILSON; SHIFT; SUN AB The use of the spherical harmonic functions to analyse the nearly steady flows in the solar photosphere is extended to situations in which B0, the latitude at disk center, is nonzero and spurious velocities are present. The procedures for extracting the rotation profile and meridional circulation are altered to account for the seasonal tilt of the Sun's rotation axis toward and away from the observer. A more robust and accurate method for separating the limb shift and meridional circulation signals is described. The analysis procedures include the ability to mask out areas containing spurious velocities (velocity-like signals that do not represent true flow velocities in the photosphere). The procedures are shown to work well in extracting the various flow components from realistic artificial data with a broad, continuous spectrum for the supergranulation. The presence of this supergranulation signal introduces errors of a few m s-1 in the measurements of the rotation profile, meridional circulation, and limb shift from a single Doppler image. While averaging the results of 24 hourly measurements has little effect in reducing these errors, an average of 27 daily measurements reduces the errors to well under 1 m s-1. RP HATHAWAY, DH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 16 TC 28 Z9 28 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1992 VL 137 IS 1 BP 15 EP 32 DI 10.1007/BF00146573 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HB313 UT WOS:A1992HB31300002 ER PT J AU NEUPERT, WM EPSTEIN, GL THOMAS, RJ THOMPSON, WT AF NEUPERT, WM EPSTEIN, GL THOMAS, RJ THOMPSON, WT TI AN EUV IMAGING SPECTROGRAPH FOR HIGH-RESOLUTION OBSERVATIONS OF THE SOLAR CORONA SO SOLAR PHYSICS LA English DT Article ID FE-IX; ULTRAVIOLET; PLASMAS; LINES AB An extreme ultraviolet (EUV) imaging spectrograph for the wavelength range from 235 to 450 angstrom has been developed and used for high resolution observations of the Sun. The instrument incorporates a glancing incidence Wolter Type II Telescope and a near-normal incidence toroidal grating spectrograph to achieve near-stigmatic performance over this spectral range. The design of the spectrograph entrance aperture enables both stigmatic spectra with spectral resolution adequate to observe emission line profiles and spectroheliograms of restricted portions of the Sun to be obtained concurrently. In this paper we describe the design and performance of the instrument and provide an overview of results obtained during a sounding rocket flight on May 5, 1989. C1 APPL RES CORP,LANDOVER,MD 20785. RP NEUPERT, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Thompson, William/D-7376-2012 NR 28 TC 67 Z9 67 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1992 VL 137 IS 1 BP 87 EP 104 DI 10.1007/BF00146577 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HB313 UT WOS:A1992HB31300006 ER PT J AU KUZNETZ, LH AF KUZNETZ, LH TI MARS MISSION GRAVITY PROFILE SIMULATION EXPERIMENT SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article AB An international cooperative mission is proposed to address the issue of whether artificial gravity is required for a manned mission to Mars. Current mission architectures use complex, heavy, and costly designs using rotating or tethered spacecraft to provide artificial gravity. This proposal presents a Space Shuttle mission to the Soviet MIR Space Station combined with an earth-based study as a means of answering the question of, "Do we need artificial gravity?" The mission is divided into 8 phases, each designed to simulate a specific phase of the manned Mars mission. Launch from Earth to the MIR station is initially provided by the U.S.S.R., while transfer of the crew and return to Earth, reboost back to MIR and final return to Earth are provided by the U.S. Space Shuttle. Zero gravity simulating the outbound leg to Mars and the return leg to Earth is provided on the MIR Space Station. Simulated Mars gravity is provided by several different methods at NASA Ames Research Center. Medical and physiological monitoring and mission activity simulation is provided continuously. A follow-on program is also proposed providing for construction of an international variable gravity research facility linked to MIR by a tether. This would be the second step of an evolutionary process leading to a joint international manned mission to Mars. RP KUZNETZ, LH (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 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 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD JAN PY 1992 VL 12 IS 1 BP 1 EP 7 PG 7 WC Engineering, Aerospace SC Engineering GA GY701 UT WOS:A1992GY70100001 ER PT J AU BERWIN, RW CUDDY, DT HILLAND, JE HOLT, B AF BERWIN, RW CUDDY, DT HILLAND, JE HOLT, B TI DESIGN, TEST, AND APPLICATIONS OF THE ALASKA SAR FACILITY SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article AB The Alaska Synthetic Aperture Radar (SAR) Facility (ASF) has been implemented to receive, record, process, and archive SAR images at the University of Alaska Fairbanks (UAF) and to utilize the data in support of scientific investigations in geophysical processes. Currently, the ASF will acquire SAR data from the European Space Agency's (ESA) European Remote Sensing satellite (E-ERS-1) and the National Space Development Agency (NASDA) of Japan Earth Resources Satellite (J-ERS-1). In the future ASF will acquire data from the Canadian Space Agency (CSA) RADARSAT. SAR imagery has proven to be a valuable research tool in scientific applications, including oceanography, geology, glaciology, hydrology, and ecology. The ASF has been designed based on specific science requirements to best utilize the spaceborne SAR imagery. In this paper, we describe the key science requirements, the overall design, and the innovative testing approaches that have been used to ensure the functionality of the ASF. RP BERWIN, RW (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD JAN PY 1992 VL 12 IS 1 BP 91 EP 104 PG 14 WC Engineering, Aerospace SC Engineering GA GY701 UT WOS:A1992GY70100010 ER PT B AU NEWMAN, JC AF NEWMAN, JC BE Blom, AF Beevers, CJ TI ADVANCES IN FATIGUE LIFE PREDICTION METHODOLOGY FOR METALLIC MATERIALS SO THEORETICAL CONCEPTS AND NUMERICAL ANALYSIS OF FATIGUE LA English DT Proceedings Paper CT Conference on Theoretical Concepts and Numerical Analysis of Fatigue CY MAY 25-27, 1992 CL UNIV BIRMINGHAM, BIRMINGHAM, ENGLAND HO UNIV BIRMINGHAM C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ENGINEERING MATERIALS ADVISORY SERVICES LTD PI WARLEY PA 339 HALESOWEN RD, CRADLEY HEATH, WARLEY, W MIDLANDS, ENGLAND B64 6PH BN 0-947817-57-3 PY 1992 BP 301 EP 325 PG 25 WC Materials Science, Characterization & Testing; Statistics & Probability SC Materials Science; Mathematics GA BB17W UT WOS:A1992BB17W00014 ER PT J AU VIJAYARAGHAVAN, D KEITH, TG AF VIJAYARAGHAVAN, D KEITH, TG TI EFFECT OF TYPE AND LOCATION OF OIL GROOVE ON THE PERFORMANCE OF JOURNAL BEARINGS SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 46TH ANNUAL MEETING OF THE SOC OF TRIBOLOGISTS AND LUBRICATION ENGINEERS CY APR 29-MAY 02, 1991 CL MONTREAL, CANADA SP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS AB A numerical study is performed of oil groove type (circumferential and axial), groove number (single and double) and groove location on journal bearing performance. The analysis involves the use of a cavitation algorithm. The interaction between cavitation phenomena and grooving is determined. Quantitative information is provided which will aid designers to better locate oil feed grooves. C1 UNIV TOLEDO, TOLEDO, OH 43606 USA. RP VIJAYARAGHAVAN, D (reprint author), NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 15 TC 4 Z9 4 U1 0 U2 1 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 JAN PY 1992 VL 35 IS 1 BP 98 EP 106 DI 10.1080/10402009208982095 PG 9 WC Engineering, Mechanical SC Engineering GA GY829 UT WOS:A1992GY82900014 ER PT J AU WATSON, AB AF WATSON, AB TI TRANSFER OF CONTRAST SENSITIVITY IN LINEAR VISUAL NETWORKS SO VISUAL NEUROSCIENCE LA English DT Article DE CONTRAST SENSITIVITY; RECEPTIVE FIELDS; NOISE; NEURAL NETWORKS; VISUAL CORTEX; LATERAL GENICULATE NUCLEUS ID RETINAL GANGLION-CELLS; LATERAL GENICULATE-NUCLEUS; TEMPORAL-FREQUENCY-SELECTIVITY; CAT STRIATE CORTEX; RECEPTIVE-FIELDS; SPATIAL-FREQUENCY; CORTICAL-CELLS; MACAQUE MONKEY; PRIMATE RETINA; NEURONS AB Contrast sensitivity is a useful measure of the ability of an observer to distinguish contrast signals from noise. Although usually applied to human observers, contrast sensitivity can also be defined operationally for individual visual neurons. In a model linear neuron consisting of a filter and noise source, this operational measure is a function of filter gain, noise power spectrum, signal duration, and a performance criterion. This definition allows one to relate the sensitivities of linear neurons at different levels in the visual pathway. Mathematical formulae describing these relationships are derived, and the general model is applied to the specific problem of relating the sensitivities of parvocellular LGN neurons and cortical simple cells in the primate. RP WATSON, AB (reprint author), NASA,AMES RES CTR,MS262-2,MOFFETT FIELD,CA 94035, USA. NR 45 TC 25 Z9 25 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0952-5238 J9 VISUAL NEUROSCI JI Visual Neurosci. PD JAN PY 1992 VL 8 IS 1 BP 65 EP 76 PG 12 WC Neurosciences; Ophthalmology SC Neurosciences & Neurology; Ophthalmology GA GX706 UT WOS:A1992GX70600008 PM 1739678 ER PT S AU POWELL, JA NEUDECK, PG MATUS, LG PETIT, JB AF POWELL, JA NEUDECK, PG MATUS, LG PETIT, JB BE Moustakas, TD Pankove, JI Hamakawa, Y TI PROGRESS IN SILICON-CARBIDE SEMICONDUCTOR TECHNOLOGY SO WIDE BAND GAP SEMICONDUCTORS SE Materials Research Society Symposium Proceedings LA English DT Proceedings Paper CT SYMP ON WIDE BAND GAP SEMICONDUCTORS, AT THE 1991 FALL MEETING OF THE MATERIALS RESEARCH SOC CY DEC 02-06, 1991 CL BOSTON, MA SP MAT RES SOC, USAF, OFF SCI RES, USN, OFF NAVAL RES, NATL RENEWABLE ENERGY LAB, BANDGAP TECHNOL, KENNAMETAL, NIPPONDENSO, SANYO ELECT C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 0 TC 18 Z9 18 U1 0 U2 1 PU MATERIALS RESEARCH SOC PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-136-0 J9 MATER RES SOC SYMP P PY 1992 VL 242 BP 495 EP 505 PG 11 WC Materials Science, Ceramics; Physics, Condensed Matter SC Materials Science; Physics GA BW28F UT WOS:A1992BW28F00068 ER PT J AU TRAJMAR, S RATLIFF, JM CSANAK, G CARTWRIGHT, DC AF TRAJMAR, S RATLIFF, JM CSANAK, G CARTWRIGHT, DC TI PROPOSED STANDARD INELASTIC DIFFERENTIAL ELECTRON-SCATTERING CROSS-SECTIONS - EXCITATION OF THE 21P LEVEL IN HE SO ZEITSCHRIFT FUR PHYSIK D-ATOMS MOLECULES AND CLUSTERS LA English DT Article ID ANGULAR-CORRELATION PARAMETERS; DISTORTED-WAVE APPROXIMATION; IMPACT EXCITATION; INTERMEDIATE ENERGIES; ELASTIC-SCATTERING; POLARIZATION FRACTIONS; HELIUM SCATTERING; ATOM SCATTERING; STATES AB Differential and integral cross section data for electron-impact excitation of the 2(1)P level in He have been critically reviewed. Experimental and theoretical results have been compared and a set of differential cross sections at 20-degrees scattering angle in the 25 to 500 eV impact energy range has been deduced based on all available information. It is proposed that this set of data represents the most accurate inelastic differential cross sections available at the present time and could be used as a secondary standard for normalization of cross sections. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP TRAJMAR, S (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 43 TC 22 Z9 22 U1 2 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0178-7683 J9 Z PHYS D ATOM MOL CL JI Z. Phys. D-Atoms Mol. Clusters PD JAN PY 1992 VL 22 IS 2 BP 457 EP 462 PG 6 WC Physics, Atomic, Molecular & Chemical SC Physics GA GY771 UT WOS:A1992GY77100003 ER PT J AU ROBERTS, DA GHOSH, S GOLDSTEIN, ML MATTHAEUS, WH AF ROBERTS, DA GHOSH, S GOLDSTEIN, ML MATTHAEUS, WH TI MAGNETOHYDRODYNAMIC SIMULATION OF THE RADIAL EVOLUTION AND STREAM STRUCTURE OF SOLAR-WIND TURBULENCE SO PHYSICAL REVIEW LETTERS LA English DT Article ID MHD TURBULENCE; INNER HELIOSPHERE; 0.3 AU; FLUCTUATIONS; DEPENDENCE; SPECTRA; ORIGIN; SPEED AB We present a unified interpretation of observations of interplanetary fluctuations in terms of nearly incompressible magnetohydrodynamics. Incompressive effects explain the rapid evolution of turbulence in slow wind containing the heliospheric current sheet. The relative constancy of the spectrum of "inward propagating" fluctuations compared to the rapid decline in "outward" fluctuations results from incompressive spectral transfer combined with strong dissipation of the outward fluctuations. Secondary compressive effects account for nearly pressure-balanced structures and the density fluctuation levels. C1 UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP ROBERTS, DA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI Goldstein, Melvyn/B-1724-2008 NR 27 TC 72 Z9 72 U1 1 U2 1 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 DEC 30 PY 1991 VL 67 IS 27 BP 3741 EP 3744 DI 10.1103/PhysRevLett.67.3741 PG 4 WC Physics, Multidisciplinary SC Physics GA GX161 UT WOS:A1991GX16100003 ER PT J AU CHENG, LT TAM, W STEVENSON, SH MEREDITH, GR RIKKEN, G MARDER, SR AF CHENG, LT TAM, W STEVENSON, SH MEREDITH, GR RIKKEN, G MARDER, SR TI EXPERIMENTAL INVESTIGATIONS OF ORGANIC MOLECULAR NONLINEAR OPTICAL POLARIZABILITIES .1. METHODS AND RESULTS ON BENZENE AND STILBENE DERIVATIVES SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SUBSTITUTED CONJUGATED MOLECULES; 2ND HARMONIC-GENERATION; 3RD-HARMONIC GENERATION; ORDER HYPERPOLARIZABILITIES; AROMATIC-COMPOUNDS; LENGTH DEPENDENCE; SUSCEPTIBILITIES; SYSTEMS; HYPERPOLARISABILITY; LIQUIDS AB In a series of two contributions, we present results of our systematic effort in the investigation of organic molecular hyperpolarizabilities using solution-phase dc electric field induced second-harmonic generation (EFISH) and third-harmonic generation (THG) experiments. In the present contribution, the experimental details, theoretical models, and data analysis scheme of a relatively precise and efficient EFISH/THG characterization method are described. Measurement results on donor-acceptor-substituted benzene and stilbene derivatives are presented. Structure-property relationships concerning intrinsic molecular nonlinearities are discussed, including issues concerning the electronic biasing strengths of various donor and acceptor groups, charge-transfer enhancement, substitution pattern, and multiple substituents. Correlations between hyperpolarizability (beta) and substituent constants as well as property trade-off between nonlinearity and optical transparency are established. The observed relations are compared with the prediction of a widely accepted two-state model. The influences of heteroatom and various additional side-group substitutions on hyperpolarizability and the charge-transfer band position are examined. Structural dependencies of the cubic polarizability are also discussed. C1 PHILIPS RES LABS, 5600 JA EINDHOVEN, NETHERLANDS. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP CHENG, LT (reprint author), DUPONT CO, DEPT CENT RES & DEV, EXPTL STN, POB 80356, WILMINGTON, DE 19880 USA. NR 55 TC 761 Z9 779 U1 3 U2 64 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 DEC 26 PY 1991 VL 95 IS 26 BP 10631 EP 10643 DI 10.1021/j100179a026 PG 13 WC Chemistry, Physical SC Chemistry GA GY164 UT WOS:A1991GY16400026 ER PT J AU CHENG, LT TAM, W MARDER, SR STIEGMAN, AE RIKKEN, G SPANGLER, CW AF CHENG, LT TAM, W MARDER, SR STIEGMAN, AE RIKKEN, G SPANGLER, CW TI EXPERIMENTAL INVESTIGATIONS OF ORGANIC MOLECULAR NONLINEAR OPTICAL POLARIZABILITIES .2. A STUDY OF CONJUGATION DEPENDENCES SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID STATE DIPOLE-MOMENT; AROMATIC-COMPOUNDS; LENGTH DEPENDENCE; HYPERPOLARIZABILITIES; SUSCEPTIBILITIES; NITROANILINES; DERIVATIVES; POLYMERS; SERIES AB In the present contribution, we broaden our investigations to include the conjugation dependences of molecular optical hyperpolarizabilities. In addition to the benzene and stilbene derivatives reported earlier, dc electric field induced second-harmonic generation (EFISH) and third-harmonic generation (THG) measurement results on the hyperpolarizabilities of a wide range of donor-acceptor-substituted pi-systems are presented. These include results for styrene, biphenyl, fluorene, diphenylacetylene, various phenylvinyl heterocyclics, oligomeric polyphenyl, alpha,omega-diphenylpolyyne, alpha-phenylpolyene, and alpha,omega-diphenylpolyene, as well as other extended phenylvinyl derivatives. Drawing from the experimental phenomenology illustrated by a large set of internally consistent data, issues concerning the efficacies of various conjugation units, conjugation planarity, aromaticity and bond alternation, and electron localization and delocalization effects, as well as the conjugation length and end-group dependences, are examined. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. PHILIPS RES LABS,5600 JA EINDHOVEN,NETHERLANDS. NO ILLINOIS UNIV,DEPT CHEM,DE KALB,IL 60115. RP CHENG, LT (reprint author), DUPONT CO,DEPT CENT RES & DEV,EXPTL STN,POB 80356,WILMINGTON,DE 19880, USA. NR 42 TC 461 Z9 468 U1 2 U2 32 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 DEC 26 PY 1991 VL 95 IS 26 BP 10643 EP 10652 DI 10.1021/j100179a027 PG 10 WC Chemistry, Physical SC Chemistry GA GY164 UT WOS:A1991GY16400027 ER PT J AU LANGHOFF, SR BAUSCHLICHER, CW PARTRIDGE, H SODUPE, M AF LANGHOFF, SR BAUSCHLICHER, CW PARTRIDGE, H SODUPE, M TI THEORETICAL-STUDY OF ONE AND 2-AMMONIA MOLECULES BOUND TO THE 1ST-ROW TRANSITION-METAL IONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID 2 WATER-MOLECULES; BINDING-ENERGIES; POSITIVE-IONS; BASIS SETS; ROW ATOMS; 1ST; ORBITALS AB The binding energies of MNH3+ and M(NH3)2+ where M = (Sc-Cu) are studied using the modified coupled-pair functional (MCPF) approach. These results are compared with experiment and with previous comparable calculations performed for the water and diwater systems. In addition to the electrostatic interaction, other factors such as 4s4p or 4s3d-sigma hybridization and 4s to 3d promotion on the metal atom contribute to determining the ground state and the magnitude of the binding energy. All of the M(NH3)2+ systems have linear NMN ground-state structures. However, for Mn(NH3)2+, the lowest septet state has a bent structure that is only 1 kcal/mol higher than the 5A1g linear D3d ground state. In contrast, Mn(H2O)2+ has a bent 7A1 ground state. This difference is probably due to the greater electrostatic binding in the ammonia systems, which favors the low-spin linear state due to its much shorter bond length. We find the second ligand binding energy to be less than the first except for Cr+, Fe+, and Co+. Overall the theoretical binding energies agree with experiment to within about 6 kcal/mol, except for the first ligand binding energy for V+ and both ligand binding energies for Co+. RP LANGHOFF, SR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 18 TC 91 Z9 91 U1 0 U2 7 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 DEC 26 PY 1991 VL 95 IS 26 BP 10677 EP 10681 DI 10.1021/j100179a031 PG 5 WC Chemistry, Physical SC Chemistry GA GY164 UT WOS:A1991GY16400031 ER PT J AU SCHAEFER, B AF SCHAEFER, B TI HEAVENLY SIGNS SO NEW SCIENTIST LA English DT Article RP SCHAEFER, B (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 SN 0262-4079 J9 NEW SCI JI New Sci. PD DEC 21 PY 1991 VL 132 IS 1800-1 BP 48 EP 51 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GW898 UT WOS:A1991GW89800043 ER PT J AU KIMES, DS SMITH, JA AF KIMES, DS SMITH, JA TI INCLINATION DISTRIBUTIONS AND SIZE MEASUREMENTS OF HEMLOCK AND RED SPRUCE NEEDLES SO APPLIED OPTICS LA English DT Note RP KIMES, DS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 623,GREENBELT,MD 20771, USA. NR 5 TC 6 Z9 6 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 1991 VL 30 IS 36 BP 5226 EP 5228 PG 3 WC Optics SC Optics GA HA508 UT WOS:A1991HA50800004 PM 20717349 ER PT J AU TOTH, RA AF TOTH, RA TI LINE-FREQUENCY MEASUREMENTS AND ANALYSIS OF N2O BETWEEN 900 AND 4700 CM-1 SO APPLIED OPTICS LA English DT Article ID VIBRATION-ROTATION BANDS; REGION; PARAMETERS; SPECTRUM AB The N2O infrared spectrum from 900 to 4700 cm-1 has been studied with a high-resolution Fourier-transform spectrometer. Measurements were made of line frequencies of several N2O isotopes for several ground-state and hot bands. A few of these bands are being reported for the first time, to my knowledge: the 1530-0330, 2330-0330, 0441-0440, 0441-0330, 0531-0330, and 1331-0330 bands of (N2O)-N-14-O-16. Also for the first time to my knowledge, perturbation-enhanced transitions in the 0710-0110 and 0730-0110 bands were assigned and measured. The frequencies have been analyzed to obtain a unique set of effective vibration-rotation parameters for each vibrational state. The results obtained from this research are of high accuracy for the ground-state and the first-excited-state bands of (N2O)-N-14-O-16, in which the computed frequencies derived from the least-squares fits are known to an absolute uncertainty of only +/- 4 x 10(-5) for nonperturbed transitions. RP TOTH, RA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 11 TC 49 Z9 49 U1 3 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 1991 VL 30 IS 36 BP 5289 EP 5315 PG 27 WC Optics SC Optics GA HA508 UT WOS:A1991HA50800015 PM 20717360 ER PT J AU WEST, RA AF WEST, RA TI OPTICAL-PROPERTIES OF AGGREGATE PARTICLES WHOSE OUTER DIAMETER IS COMPARABLE TO THE WAVELENGTH SO APPLIED OPTICS LA English DT Article DE AGGREGATE PARTICLES; AEROSOLS; REMOTE SENSING; OPTICAL PROPERTIES; POLARIZATION ID DIFFUSION-LIMITED AGGREGATION; AEROSOL SIZE DISTRIBUTIONS; SCATTERING; GRAINS; APPROXIMATION; LIGHT; DUST AB I describe results of numerical calculations of the optical properties (extinction efficiency, single-scattering albedo, phase function, and linear polarization) of aggregate particles whose outer diameter is comparable with the wavelength. Results are presented for two types of particle, one composed of monomers whose radius is small compared with the wavelength and a second containing monomers with larger radii. The shape of the forward-scattered lobe of the phase function is diagnostic of the mean projected area (but differs from that for an equal-area sphere), while the linear polarization, phase function at large scattering angles, and single-scattering albedo depend on the monomer diameter. The wavelength dependence of the extinction efficiency differs markedly from that for equal-area spheres. These results can be used to infer particle properties from remotely sensed data. RP WEST, RA (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 106 Z9 108 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 1991 VL 30 IS 36 BP 5316 EP 5324 PG 9 WC Optics SC Optics GA HA508 UT WOS:A1991HA50800016 PM 20717361 ER PT J AU CARILLI, CL PERLEY, RA DREHER, JW LEAHY, JP AF CARILLI, CL PERLEY, RA DREHER, JW LEAHY, JP TI MULTIFREQUENCY RADIO OBSERVATIONS OF CYGNUS-A - SPECTRAL AGING IN POWERFUL RADIO GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (CYGNUS-A); GALAXIES, JETS; RADIATION MECHANISMS; RADIO SOURCES, GALAXIES ID COSMIC-RAYS; PARTICLE-ACCELERATION; SHOCK FRONTS; HOT SPOTS; PROPAGATION; GHZ; ALGORITHM; TRANSPORT; BRIDGES; LOBES AB We present a detailed analysis of the radio spectrum across the lobes of Cygnus A. These observations provide the first critical test of synchrotron spectral aging theory. The results are in good agreement with the jet model for powerful radio galaxies, involving particle acceleration at the hot spots and outflow into the radio lobes, with subsequent energy loss due to synchrotron radiation. The hot spot spectra are well represented by a spectral aging model involving continuous injection of relativistic particles. Both hot spots have spectral break frequencies around 10 GHz. We find an injection index of -0.5 for both hot spots, consistent with diffusive shock acceleration at a strong, nonrelativistic shock in a Newtonian fluid. The low-frequency hot spot emission spectrum falls below the injected power law. This effect is isolated to the hot spots, and is best explained by a low-energy cutoff in the particle distribution, as predicted by Bell in his original work on diffusive shock acceleration. We find that expansion losses may be significant going from the hot spots to the lobes, but that beyond a few arcseconds from the hot spots the dominant energy loss mechanism is synchrotron radiation. The break frequency distribution across each lobe shows a clear trend of decreasing break frequency with distance from the hot spot. The lowest break frequency in the source is 750 MHz, which implies a source age of 6 Myr in minimum-energy magnetic fields. The separation velocity assuming minimum-energy fields is 0.06c(H-0 = 75 km s-1 Mpc-1). This is much larger than the source advance speed required for ram-pressure confinement of the heads of the lobes, assuming a minimum-energy configuration for the particles and fields. A self-consistent model is possible in which the fields are a factor of 3 below minimum-energy values. This results in a source advance speed approximately equal to the separation velocity, almost-equal-to 0.01c, and a source age of 30 Myr. The lobe spectra fall off more steeply than allowed by the continuous injection model at high frequency, but less steeply than exponential. The lobe spectra are well represented by a spectral model involving "one-shot" injection and subsequent energy loss through synchrotron radiation, without continuous isotropization of the pitch-angle distribution. At 1".5 resolution, we find break frequencies much greater than 10 GHz beyond 2" from the hot spots. This is inconsistent with a simple hot spot model involving particle injection at a single point and radiative losses in an axisymmetric outflow from this point, and suggests spatially distributed particle acceleration in the vicinity of the hot spots and/or highly asymmetric outflow. We also find that the injection index across the lobes is -0.7. Such a value is difficult to reconcile with the observed hot spot injection indices of -0.5. The cause for this injection index discrepancy remains a mystery. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NUFFIELD RADIO ASTRON OBSERV LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. RP CARILLI, CL (reprint author), NATL RADIO ASTRON OBSERV,POB O,SOCORRO,NM 87801, USA. NR 76 TC 257 Z9 258 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 DEC 20 PY 1991 VL 383 IS 2 BP 554 EP 573 DI 10.1086/170813 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW194 UT WOS:A1991GW19400008 ER PT J AU STOTHERS, RB AF STOTHERS, RB TI OBSERVATIONAL TESTS OF CONVECTIVE CORE OVERSHOOTING IN STARS OF INTERMEDIATE TO HIGH MASS IN THE GALAXY SO ASTROPHYSICAL JOURNAL LA English DT Article DE CONVECTION; STARS, ABUNDANCES; STARS, EVOLUTION; STARS, INTERIORS ID LARGE MAGELLANIC CLOUD; EMPIRICAL EFFECTIVE TEMPERATURES; UVBY-BETA-PHOTOMETRY; B-TYPE STARS; ABSOLUTE-MAGNITUDE CALIBRATION; MAIN-SEQUENCE STARS; AGE OPEN CLUSTERS; EVOLUTIONARY MODELS; SOUTHERN CLUSTERS; YOUNG CLUSTERS AB Fourteen tests for the presence of convective overshooting in large convecting stellar cores are discussed for stars with masses of 4-17 M. which are members of detached close binary systems and of open clusters in the Galaxy. Nine of these tests, including all the best tests, are either new or newly applied. A large amount of theoretical and observational data has been scrutinized and subjected to averaging in order to minimize accidental and systematic errors. Defining a ratio of the effective convective overshoot distance beyond the classical Schwarzschild core boundary to the local pressure scale height, the present investigation finds a conservative upper limit of d/H(P) < 0.4 from at least four tests and a tighter upper limit of d/H(P) < 0.2 from one good test that is subject to only mild restrictions and is based on the maximum observed effective temperature of evolved blue supergiants. All the best test results, however, are formally consistent with the assumption d/H(P) = 0 and are not sensitive to uncertainties about the initial chemical composition (or, probably, the opacities). Further analysis shows why the values of d/H(P) = 0.25-2 that were derived in previous studies should probably be regarded as only upper limits. Three additional conclusions can be drawn specifically concerning the B-type main-sequence stars. First, any current uncertainty about the distance scale for these stars is unimportant in conducting the present tests for convective core overshooting. Second, the correct effective temperature scale for the B0.5-B2 stars is almost certainly close to one of the proposed hot scales. Third, the value of the initial metals abundance that is required in stellar models in order to reproduce the observations is Z(e) almost-equal-to 0.04 independently of overshooting; this exceptionally high value, which is twice the directly observed atmospheric metals abundance in most of these stars, may indicate the need for larger envelope opacities than the standard Los Alamos opacities used here. RP STOTHERS, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 201 TC 50 Z9 50 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 DEC 20 PY 1991 VL 383 IS 2 BP 820 EP 836 DI 10.1086/170840 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW194 UT WOS:A1991GW19400035 ER PT J AU AKE, TB JOHNSON, HR AMEEN, MM AF AKE, TB JOHNSON, HR AMEEN, MM TI AN INTERACTIVE COMPANION TO THE S-STAR HD-35155 SO ASTROPHYSICAL JOURNAL LA English DT Article DE SPECTROPHOTOMETRY; STARS, BINARIES; STARS, INDIVIDUAL (HD-35155); STARS, S-TYPE; ULTRAVIOLET, SPECTRA ID OUTER ATMOSPHERIC STRUCTURE; STELLAR ANGULAR DIAMETERS; ASYMPTOTIC GIANT BRANCH; WHITE-DWARF COMPANION; CHEMICAL-COMPOSITION; RED GIANTS; EFFECTIVE TEMPERATURES; MODEL ATMOSPHERES; COOL STARS; TECHNETIUM AB Although relatively unremarkable in the visual, the S star HD 35155 (S3/2) shows strong emission lines of multiply ionized species and excess continuous emission shortward of 2000 angstrom. Several ultraviolet spectra have been taken with IUE and analyzed. We find that the UV source is highly variable in the IUE region even though Eggen reported it in 1972 to be photometrically constant at optical wavelengths. Subtraction of the observed flux of a similar, single S star (HR 8714) from the ultraviolet spectrum yields a curve of excess emission which is close to a simple f-lambda approximately lambda-1 power law instead of a blackbody curve, pointing to its probable production by a cloud radiated by a hot source. There is nevertheless weak evidence for a characteristic temperature near 15,000 K for the secondary. The integrated excess flux at minimum light amounts to a luminosity of 0.2 L. at the prescribed position of the source-far too much for a white dwarf-which confirms that the excess ultraviolet light originates in a source other than the photosphere of the companion. Measurement of the emission lines indicates that they are formed in different regions of the system, with permitted lines, such as C IV, coming from a rapidly rotating accretion disk and semiforbidden lines, such as Si III] and C III], from a cloud. Of particular interest is the absence of He II 1640 angstrom, indicating the lack of a hot boundary layer of the disk. A blue cutoff on the Mg II lines indicates mass outflow, and several considerations place the hot gas in the matter thrown off by the S star. Consequences for the evolution of the S star are unclear, but there is a strong presumption that the chemical peculiarities of the red giant are due to mass transfer from a WD companion when the companion itself was an AGB star. The system may be related both to the Ba stars and the symbiotic stars. C1 INDIANA UNIV, DEPT ASTRON, BLOOMINGTON, IN 47405 USA. RP NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, ASTRON PROGRAMS, CODE 681, GREENBELT, MD 20771 USA. NR 68 TC 16 Z9 16 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 DEC 20 PY 1991 VL 383 IS 2 BP 842 EP 852 DI 10.1086/170842 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW194 UT WOS:A1991GW19400037 ER PT J AU SMALE, AP CORBET, RHD AF SMALE, AP CORBET, RHD TI A STUDY OF THE HA LINE IN X1735-444 SO ASTROPHYSICAL JOURNAL LA English DT Article DE LINE PROFILES; STARS, INDIVIDUAL (V926 SCORPII); X-RAYS, BINARIES ID X-RAY BINARIES; SCORPIUS X-1; ORBITAL PERIOD; HERCULIS; BURSTER; MODEL AB Detailed analysis of 46 optical spectra containing the H-alpha line of X1735-444 (= V926 Sco) obtained over three nights in 1987 May shows considerable variability of the line profile with phase. Using a convolution method, we derive a radial velocity curve for the whole H-alpha line with a systemic velocity of gamma = -152 +/- 20 km s-1 and a semiamplitude of K = 68 +/- 26 km s-1 (90% confidence). We combine published and unpublished photometric data to obtain an improved ephemeris for X1735-444, and using this ephemeris we find that the maximum blueshift of the H-alpha line as a whole occurs at a phase of +0.93 +/- 0.09 relative to maximum light. In an attempt to deconvolve the "base" and "peak" components of the line, we have fitted the profiles with both a simple skew model and a combination of two Gaussians. Both methods show that the position of the line peak varies sinusoidally with a semiamplitude of K(peak) approximately 190-240 km s-1 and has maximum blueshift coincident with maximum light. The line base has a smaller variation, with the marginal detection of a modulation with a velocity semiamplitude of K(base) approximately 70 km s-1 which leads the peak component by approximately 0.34 in phase. The peak contributes approximately 20% to the total H-alpha emission. We suggest that two distinct regions contribute to the observed profile in X1735-444: the peak emission is associated with the accretion stream of material passing between the companion and the compact object, or with the impact point where this stream intersects the disk; and the base emission is produced symmetrically in the outer accretion disk. The observed velocities and derived system parameters lead to a most probable system inclination of i = 10-degrees-20-degrees. C1 PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,DAVEY LAB 525,UNIV PK,PA 16802. RP SMALE, AP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 666,GREENBELT RD,GREENBELT,MD 20771, USA. NR 36 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 1991 VL 383 IS 2 BP 853 EP 859 DI 10.1086/170843 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW194 UT WOS:A1991GW19400038 ER PT J AU WESTPHAL, DL TOON, OB AF WESTPHAL, DL TOON, OB TI SIMULATIONS OF MICROPHYSICAL, RADIATIVE, AND DYNAMIC PROCESSES IN A CONTINENTAL-SCALE FOREST-FIRE SMOKE PLUME SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AIR-POLLUTION; SATELLITE MEASUREMENTS; SAHARAN DUST; ABSORPTION; ATMOSPHERE; DEPOSITION; PARTICLES; TRANSPORT; AEROSOLS AB A numerical model of meterology, aerosols, and radiative transfer is used to study the impact of a large forest fire smoke plume on atmospheric processes. The simulated smoke optical depths at 0.63-mu-m wavelength are in agreement with analyses of satellite data and show values as high as 1.8. The smoke has an albedo of 35%, or more than double the clear-sky value, and cools the surface by as much as 5 K. The best agreement with the analyses of optical depth and surface cooling is obtained when a fuel loading more than 10 times that which has been previously suggested is used to calculate the initial smoke mass load. An imaginary refractive index, n(im), of 0.01 yields results which closely match the observed cooling, single scattering albedo, and the Angstrom wavelength exponent. An n(im) of 0.1, typical of smoke from urban fires, produces 9 K cooling. Coagulation causes the geometric mean radius by number to increase from the initial value of 0.08-mu-m to a final value of 0.15-mu-m while the specific extinction and absorption increase by 40% and 25%, respectively. After 42 hours, these changes in the smoke optical properties lead to a 32% increase in optical depth and an 11% increase in surface cooling over that found in a simulation where coagulation is not allowed. In the model, 47% of the smoke is removed by scavenging as it is incorporated into the frontal zone over the Great Lakes. Self-lofting of the smoke in a direct, smoke-induced circulation is observed in the baseline simulation and is much stronger in the urban smoke simulation. RP WESTPHAL, DL (reprint author), NASA, AMES RES CTR, MAIL STOP 245-5, MOFFETT FIELD, CA 94035 USA. NR 44 TC 74 Z9 75 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22379 EP 22400 DI 10.1029/91JD01956 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900012 ER PT J AU THOMASON, LW AF THOMASON, LW TI A DIAGNOSTIC STRATOSPHERIC AEROSOL SIZE DISTRIBUTION INFERRED FROM SAGE-II MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONDENSATION NUCLEI; OPTICAL-MODEL; 2 WAVELENGTHS; EXTINCTION; VALIDATION; SATELLITE AB An aerosol size distribution model for the stratosphere is inferred based on 5 years of Stratospheric Aerosol and Gas Experiment (SAGE) II measurements of multispectral aerosol and water vapor extinction. The SAGE II aerosol and water vapor extinction data strongly suggest that there is a critical particle radius below which there is a relatively weak dependence of particle number density with size and above which there are few, if any, particles. A segmented power law model, as a simple representation of this dependence, is used in theoretical calculations and intercomparisons with a variety of aerosol measurements including dustsondes, longwave lidar, and wire impactors and shows a consistently good agreement. RP THOMASON, LW (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL CODE 475, HAMPTON, VA 23665 USA. OI Thomason, Larry/0000-0002-1902-0840 NR 19 TC 46 Z9 47 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22501 EP 22508 DI 10.1029/91JD02521 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900019 ER PT J AU PARK, JH CARLI, B AF PARK, JH CARLI, B TI SPECTROSCOPIC MEASUREMENT OF HO2, H2O2 AND OH IN THE STRATOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BALLOON-BORNE LIDAR; INSITU MEASUREMENTS; HYDROGEN-PEROXIDE; LINE ASSIGNMENTS; MATRIX-ISOLATION; MIXING-RATIO; SUBMILLIMETER; COMPILATION; MILLIMETER; RESONANCE AB Stratospheric concentrations of HO2, H2O2, and OH have been retrieved simultaneously from the far infrared emission spectra obtained with a balloon-borne Fourier transform spectrometer in June 1983 at 32-degrees-N latitude. Retrieved concentrations of HO2 and H2O2 are reported in this paper, along with vertical distributions of OH which were reported in an earlier paper for the afternoon, sunset, and nighttime periods for altitudes from 26 to 38 km. HO2 distributions are obtained with uncertainties that are about the same as OH for the same vertical range and for the afternoon and sunset periods. H2O2 concentrations is obtained at an altitude of 30 km for the period that covers afternoon and sunset hours. The retrieved concentrations of these HOx species agree well with other individually measured results and the steady state photochemical predictions. The ratio HO2/OH at around 32 km seems to increase from the afternoon period to the sunset period. C1 CNR, IST RIC ONDE ELECTROMAGNET, I-50127 FLORENCE, ITALY. RP PARK, JH (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. NR 29 TC 25 Z9 25 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22535 EP 22541 DI 10.1029/91JD02327 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900021 ER PT J AU JACKMAN, CH DOUGLASS, AR BRUESKE, KF KLEIN, SA AF JACKMAN, CH DOUGLASS, AR BRUESKE, KF KLEIN, SA TI THE INFLUENCE OF DYNAMICS ON 2-DIMENSIONAL MODEL RESULTS - SIMULATIONS OF C-14 AND STRATOSPHERIC AIRCRAFT NOX INJECTIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TWO-DIMENSIONAL MODEL; EXCESS C-14; MIDDLE ATMOSPHERE; ODD NITROGEN; OZONE; CIRCULATION; SENSITIVITY; EXCHANGE; MASS; LIMS AB A two-dimensional (2D) photochemical model (latitude range from -85-degrees to +85-degrees and altitude range from the ground to 0.23 mbar (about 60 km)) has been used to investigate the influence of dynamics on model results. We tested three representations of atmospheric transport to simulate total ozone and C-14 amounts after nuclear tests in the early 1960s. We also simulated three scenarios of NOx injections from a proposed fleet of stratospheric aircraft and their effects on ozone. The three dynamical formulations used were Dynamics A, a base dynamics used in previous work with this model; Dynamics B, a strong circulation dynamics discussed by Jackman et al. [1989a]; and Dynamics C, the dynamics used by Shia et al. [1989]. The advective component of the stratosphere to troposphere mass exchange rate (advective strat/trop exchange rate (ASTER)) is largest for Dynamics B (5.8 x 10(17) kg yr-1) and smallest for Dynamics C (1.4 x 10(17) kg yr-1), with the ASTER for Dynamics A (2.4 x 10(17) kg yr-1) being between these two extremes. Simulations of both total ozone and C-14 were worst with Dynamics B. Simulations of total ozone were best with Dynamics A and for C-14 best with Dynamics C. This illustrates the difficulty of simultaneously modeling constituents with different altitude and latitude dependencies. Ozone depletion from NOx injections of stratospheric aircraft showed a strong sensitivity to dynamics. Generally, if eddy diffusion is not changed, then a large ASTER leads to reduced ozone loss while a small ASTER leads to increased ozone loss from a given stratospheric NOx injection. C1 RES & DATA SYST CORP, GREENBELT, MD 20770 USA. UNIV WASHINGTON, DEPT ATMOSPHER SCI, SEATTLE, WA 98195 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, MAIL CODE 916, GREENBELT, MD 20771 USA. RI Douglass, Anne/D-4655-2012; Jackman, Charles/D-4699-2012; Klein, Stephen/H-4337-2016 OI Klein, Stephen/0000-0002-5476-858X NR 53 TC 24 Z9 24 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22559 EP 22572 DI 10.1029/91JD02510 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900023 ER PT J AU DICKEY, JO GHIL, M MARCUS, SL AF DICKEY, JO GHIL, M MARCUS, SL TI EXTRATROPICAL ASPECTS OF THE 40-50 DAY OSCILLATION IN LENGTH-OF-DAY AND ATMOSPHERIC ANGULAR-MOMENTUM SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTRASEASONAL TIME SCALES; GENERAL-CIRCULATION MODEL; EL-NINO; SOUTHERN OSCILLATION; EARTH ROTATION; TROPICAL ATMOSPHERE; SEASONAL-VARIATIONS; 50-DAY OSCILLATION; POLAR MOTION; FLUCTUATIONS AB Fluctuations in Earth rotation over time scales of 2 years or less are dominated by atmospheric effects; spectral analyses of length-of-day (LOD) and atmospheric angular momentum (AAM) data show significantly increased variability in the 40-50 day band. LOD and AAM fluctuations on the 40-50 day time scale have previously been linked to tropical, convectively driven waves of the type first described by Madden and Julian (1971) (referred to as MJ hereinafter). A significant spectral peak centered at 42 days has also been found, however, in the AAM of a 3-year (1120-day) perpetual-January simulation of the global atmosphere, performed using a version of the University of California at Los Angeles (UCLA) general circulation model (GCM) which does not give rise to MJ oscillations in the tropics. In the present work the 40-50 day oscillation is studied using the 12-year overlap between two records: (1) AAM data, compiled from the National Meteorological Center (NMC); and (2) LOD variation from the Jet Propulsion Laboratory Kalman-filtered Earth rotation series. We analyze the NMC records by latitude belts, in light of the UCLA GCM results, in order to identify possibly distinct sources of the AAM oscillation in the mid-latitudes and the tropics. Results suggest that two intraseasonal oscillations exist in the Earth-atmosphere system: a tropical, 50-day oscillation associated with the convectively driven MJ wave and a mid-latitude, 40-day oscillation associated with the interaction of nonzonal flow with topography. C1 UNIV CALIF LOS ANGELES, DEPT ATMOSPHER SCI, CTR CLIMATE DYNAM, LOS ANGELES, CA 90024 USA. UNIV CALIF LOS ANGELES, INST GEOPHYS & PLANETARY PHYS, LOS ANGELES, CA 90024 USA. RP DICKEY, JO (reprint author), CALTECH, JET PROP LAB, MAIL STOP 238-322, PASADENA, CA 91109 USA. NR 79 TC 63 Z9 66 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22643 EP 22658 DI 10.1029/91JD02339 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900030 ER PT J AU SCHMIDLIN, FJ LEE, HS MICHEL, W AF SCHMIDLIN, FJ LEE, HS MICHEL, W TI THE INFLATABLE SPHERE - A TECHNIQUE FOR THE ACCURATE MEASUREMENT OF MIDDLE ATMOSPHERE TEMPERATURES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID METEOROLOGICAL ROCKETSONDE AB In recent years there has been increasing interest in the utilization of the inflatable falling sphere technique for middle atmosphere studies. The falling sphere technique uses radar position information and the equation of motion to calculate density data from which temperature information is derived. Through theoretical derivation, simulation, and measurements it is demonstrated that the temperatures derived from falling spheres are not significantly affected by linear bias in the density measurements that originate from uncertainties in sphere mass, volume, or cross-sectional area. This study illustrates the sphere's capability to produce accurate temperatures up to 85 km and higher, given that the necessary reduction initialization conditions are met. At heights below 60 km, comparison of sphere temperatures with in situ thermistor measurements obtained close in space and time shows good agreement. Comparison with OH-radical rotational temperatures also confirms excellent agreement at 86 km. It is concluded that the sphere technique is an independent and highly accurate source of temperature measurement, is unique in being the only low-cost source of in situ measurement of temperature throughout the mesosphere and lower thermosphere, and qualifies as an intrinsic method to establish the accuracy of other atmospheric measurement systems. C1 SCI & ENGN SERV INC, SILVER SPRING, MD USA. UNIV DAYTON, RES INST, WALLOPS ISL, VA USA. RP SCHMIDLIN, FJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA 23337 USA. NR 24 TC 90 Z9 90 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 20 PY 1991 VL 96 IS D12 BP 22673 EP 22682 DI 10.1029/91JD02395 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY559 UT WOS:A1991GY55900032 ER PT J AU PATRICK, EL ANDREWS, ML GARSCADDEN, A AF PATRICK, EL ANDREWS, ML GARSCADDEN, A TI ELECTRON-DRIFT VELOCITIES IN XENON AND XENON-NITROGEN GAS-MIXTURES SO APPLIED PHYSICS LETTERS LA English DT Article ID KRYPTON AB The drift velocity of an electron swarm in pure xenon gas (99.995% pure) and xenon gas mixtures, containing 0.1%, 1%, and 10% nitrogen additive, was measured in a pulsed-Townsend drift tube in order to observe the effects of the additives on electron mobility, and to demonstrate negative differential conductivity. The digitized signal was analyzed by a microcomputer to produce swarm drift time measurements. The amount of nitrogen necessary to perturb the electron drift velocity in pure xenon is implied from these measurements. C1 WRIGHT STATE UNIV,DEPT PHYS,DAYTON,OH 45435. WRIGHT LAB,ADV PLASMA RES GRP,WRIGHT PATTERSON AFB,OH 45433. RP PATRICK, EL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,CODE 915,GREENBELT,MD 20771, USA. NR 9 TC 6 Z9 6 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 16 PY 1991 VL 59 IS 25 BP 3239 EP 3240 DI 10.1063/1.105744 PG 2 WC Physics, Applied SC Physics GA GV079 UT WOS:A1991GV07900012 ER PT J AU GEORGE, T FATHAUER, RW AF GEORGE, T FATHAUER, RW TI ENDOTAXIAL GROWTH OF COSI2 WITHIN (111) ORIENTED SI IN A MOLECULAR-BEAM EPITAXY SYSTEM SO APPLIED PHYSICS LETTERS LA English DT Article ID CRYSTAL AB A new mode of growth is reported in which buried metallic layers can be fabricated within a single-crystal semiconductor through preferential subsurface growth on previously-grown "seed" regions. The deposition of Co at 800-degrees-C at a rate of 0.01 nm/s on (111) Si substrates containing buried CoSi2 columns 40-100 nm below the Si surface results in the growth and coalescence of these subsurface columns. The formation of a CoSi2 layer on the Si surface is suppressed by this growth mode. It is proposed that the high diffusion rate of Co at 800-degrees-C, coupled with the high growth rate of CoSi2 at the subsurface columns, is responsible for this preferred "endotaxial" growth mode. This growth technique was used to produce a continuous buried single-crystal layer of CoSi2 under a single-crystal Si capping layer. RP GEORGE, T (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 14 TC 27 Z9 27 U1 0 U2 4 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 DEC 16 PY 1991 VL 59 IS 25 BP 3249 EP 3251 DI 10.1063/1.105747 PG 3 WC Physics, Applied SC Physics GA GV079 UT WOS:A1991GV07900016 ER PT J AU JUNG, KH SHIH, S HSIEH, TY KWONG, DL LIN, TL AF JUNG, KH SHIH, S HSIEH, TY KWONG, DL LIN, TL TI INTENSE PHOTOLUMINESCENCE FROM LATERALLY ANODIZED POROUS SI SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON AB We have studied photoluminescence (PL) from porous Si anodized laterally along the length of the Si wafer. Broad PL peaks were observed with peak intensities at approximately 640 to 720 nm. Strong PL intensity could be observed from 550 to 860 nm. Room-temperature peak intensities were within an order of magnitude of peak intensities of AlGaAs/GaAs multi-quantum wells taken at 4.2 K, and total intensities were comparable. A blue shift of peak intensities from approximately 680 to 620 nm could be observed after thermal anneal at 500-degrees-C in O2 and subsequent HF dip. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR,PASADENA,CA 91109. RP JUNG, KH (reprint author), UNIV TEXAS,DEPT ELECT & COMP ENGN,MICROELECTR RES CTR,AUSTIN,TX 78712, USA. NR 12 TC 54 Z9 58 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 16 PY 1991 VL 59 IS 25 BP 3264 EP 3266 DI 10.1063/1.105752 PG 3 WC Physics, Applied SC Physics GA GV079 UT WOS:A1991GV07900021 ER PT J AU SODUPE, M BAUSCHLICHER, CW PARTRIDGE, H AF SODUPE, M BAUSCHLICHER, CW PARTRIDGE, H TI THE METAL-LIGAND BINDING-ENERGIES FOR SR(H2O)N+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID DIPOLE-MOMENT; GAS-PHASE; HYDRATION; WATER; IONS RP SODUPE, M (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 16 TC 12 Z9 12 U1 0 U2 3 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 DEC 15 PY 1991 VL 95 IS 12 BP 9422 EP 9423 DI 10.1063/1.461174 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GV825 UT WOS:A1991GV82500077 ER PT J AU CAVALIERI, DJ AF CAVALIERI, DJ TI NASA SEA ICE VALIDATION PROGRAM FOR THE DEFENSE METEOROLOGICAL SATELLITE PROGRAM SPECIAL SENSOR MICROWAVE IMAGER SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article RP CAVALIERI, DJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. NR 8 TC 11 Z9 11 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-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 1991 VL 96 IS C12 BP 21969 EP 21970 DI 10.1029/91JC02333 PG 2 WC Oceanography SC Oceanography GA GW576 UT WOS:A1991GW57600001 ER PT J AU CAVALIERI, DJ CRAWFORD, JP DRINKWATER, MR EPPLER, DT FARMER, LD JENTZ, RR WACKERMAN, CC AF CAVALIERI, DJ CRAWFORD, JP DRINKWATER, MR EPPLER, DT FARMER, LD JENTZ, RR WACKERMAN, CC TI AIRCRAFT ACTIVE AND PASSIVE MICROWAVE VALIDATION OF SEA ICE CONCENTRATION FROM THE DEFENSE METEOROLOGICAL SATELLITE PROGRAM SPECIAL SENSOR MICROWAVE IMAGER SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID VARIABILITY; MODEL; ZONE; SNOW AB During March 1988 a series of coordinated special sensor microwave imager (SSM/I) underflights were carried out with NASA and Navy aircraft over portions of the Bering, Beaufort, and Chukchi seas as part of the NASA Defense Meteorological Satellite Program SSM/I Sea Ice Validation Program. The two Navy research aircraft, a Naval Research Laboratory P-3 with the NOARL K(a) band radiometric mapping system operating at 33.6 GHz and a Naval Air Development Center (NADC) P-3 with the NADC-Environmental Research Institute of Michigan (ERIM) C band synthetic aperture radar (SAR), provided wide-swath, high-resolution microwave imagery for direct comparison with sea ice concentrations calculated from SSM/I radiances using the NASA sea ice algorithm. Coincident measurements made with the Jet Propulsion Laboratory (JPL) C band SAR and the Goddard Space Flight Center (GSFC) aircraft multifrequency microwave radiometers (AMMR) on the NASA DC-8 airborne laboratory provided additional verification of the algorithm. NASA DC-8 AMMR data from Bering Sea ice edge crossings were used to verify that the ice edge location, defined as the position of the initial ice bands encountered by the aircraft, corresponds to an SSM/I ice concentration of 15%. Direct comparison of SSM/I and aircraft ice concentrations for regions having at least 80% aircraft coverage reveals that the SSM/I total ice concentration is lower on average by 2.4% +/- 2.4%. For multiyear ice, NASA and Navy flights across the Beaufort and Chukchi seas show that the SSM/I algorithm correctly maps the large-scale distribution of multiyear ice: the zone of first-year ice off the Alaskan coast, the large areas of mixed first-year and multiyear ice, and the region of predominantly multiyear ice north of the Canadian archipelago. Quantitative comparisons show that the SSM/I algorithm overestimates multiyear ice concentration by 12% +/- 11% on average in the Chukchi and Beaufort seas. Excluding data for a day which gave anomalously large positive biases, the multiyear ice concentration difference reduces to 5% +/- 4%, also indicating a positive SSM/I bias. Anomalously low SSM/I concentrations were found in the coastal zone north of Ellesmere Island. Differences between multiyear ice concentrations estimated from the JPL C band SAR imagery and from the GSFC AMMR radiances using an SSM/I type algorithm show that the AMMR concentrations are smaller on average by 6% +/- 14%. Sea ice conditions are described, and possible causes of the observed differences are discussed. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. USN,OCEANOG & ATMOSPHER RES LAB,HANOVER,NH 03755. ENVIRONM RES INST MICHIGAN,RADAR SCI LAB,ANN ARBOR,MI 48107. RP CAVALIERI, DJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSHER PROC LAB,GREENBELT,MD 20771, USA. RI Drinkwater, Mark/C-2478-2011 OI Drinkwater, Mark/0000-0002-9250-3806 NR 32 TC 117 Z9 123 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-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 1991 VL 96 IS C12 BP 21989 EP 22008 DI 10.1029/91JC02335 PG 20 WC Oceanography SC Oceanography GA GW576 UT WOS:A1991GW57600003 ER PT J AU EMERY, WJ RADEBAUGH, M FOWLER, CW CAVALIERI, D STEFFEN, K AF EMERY, WJ RADEBAUGH, M FOWLER, CW CAVALIERI, D STEFFEN, K TI A COMPARISON OF SEA ICE PARAMETERS COMPUTED FROM ADVANCED VERY HIGH-RESOLUTION RADIOMETER AND LANDSAT SATELLITE IMAGERY AND FROM AIRBORNE PASSIVE MICROWAVE RADIOMETRY SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article AB The advanced very high resolution radiometer (AVHRR), flying on the NOAA polar-orbiting weather satellites, can be used to map both sea ice concentration and ice edge, under cloud-free conditions. In order to evaluate the accuracy and reliability of these AVHRR ice parameters, we have compared AVHRR-derived sea ice parameters from the Bering Sea with those computed from nearly coincident (within 6 hours) Landsat multispectral scanner (MSS) imagery and from the aircraft multichannel microwave radiometer (AMMR) flown on the NASA DC-8. The higher spatial and spectral resolutions of the Landsat data make them appropriate to use as a reference for the AVHRR inferred sea ice parameters while the lower-altitude aircraft microwave sensor also provides a good source of comparison data. Both the AVHRR near-infrared (channel 2) and thermal infrared (channel 4) images were used to compute ice concentration. Mean ice concentration differences between the channel 2 AVHRR and Landsat MSS data (Landsat-AVHRR) ranged from -0.8 to 1.8% with a mean value of 0.5%. Root-mean-square (rms) differences ranged from 6.8 to 17.7%. Mean differences were larger for the channel 4 AVHRR ice concentrations ranging from -2.2 to 8.4% with rms differences from 8.6 to 26.8%. Mean differences between AVHRR channel 2 concentrations and the AMMR data (AMMR-AVHRR) ranged from -19.7 to 18.9% while rms values went from 17.0 to 44.8%. Mean ice edge differences between the Landsat and AVHRR images were 1.8 km for channel 2 and 2.9 km for channel 4 with rms differences of 3.2 km and 4.4 km, respectively. The AVHRR ice edge was south and west of the Landsat edge. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771. UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP EMERY, WJ (reprint author), UNIV COLORADO,COLORADO CTR ASTRODYNAM RES,BOULDER,CO 80309, USA. RI Steffen, Konrad/C-6027-2013 OI Steffen, Konrad/0000-0001-8658-1026 NR 13 TC 19 Z9 21 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 DEC 15 PY 1991 VL 96 IS C12 BP 22075 EP 22085 DI 10.1029/91JC02337 PG 11 WC Oceanography SC Oceanography GA GW576 UT WOS:A1991GW57600009 ER PT J AU JONES, BH MOOERS, CNK RIENECKER, MM STANTON, T WASHBURN, L AF JONES, BH MOOERS, CNK RIENECKER, MM STANTON, T WASHBURN, L TI CHEMICAL AND BIOLOGICAL STRUCTURE AND TRANSPORT OF A COOL FILAMENT ASSOCIATED WITH A JET-EDDY SYSTEM OFF NORTHERN CALIFORNIA IN JULY 1986 (OPTOMA21) SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID COASTAL SURFACE CURRENTS; SATELLITE-OBSERVATIONS; DRIFTER OBSERVATIONS; UPWELLING CENTER; PHYTOPLANKTON; VARIABILITY; FRONTS; EDDIES; CODE AB During the OPTOMA21 cruise, from July 7 to 19, 1986, the distributions of nutrient, pigment, bio-optical, and physical variables were mapped in a jet-eddy system located off Point Reyes and Point Arena, California. The goals of this mapping were to describe the three-dimensional variability of the filament and its relation to the nutrient and phytoplankton distributions offshore, to examine the interaction between the filament and coastal water, and to estimate the transport of nutrients and phytoplankton by the jet system. Several cool filaments were distinguishable at distances of more than 35-50 km from the coast in satellite imagery during this period. The juxtaposition of these features as well as the presence of an offshore anticyclone and a cyclone south of the filament anchored to the coast at Point Arena led to complex patterns in all variables, aided by the apparent alongshore variability in the source of upwelled water. The seaward jet associated with the filament entrained coastal upwelled water, with low temperatures and high nutrient and pigment concentrations, so that the filament maintained its characteristic low temperature and high chlorophyll in the offshore zone. The filament extended approximately 250 km offshore, where it made a cyclonic bend southeastward toward the coast. Salinity and nutrient concentrations generally increased across the filament into the cyclonic eddy circumscribed by the filament, although their fronts were not always coincident with temperature fronts. Chlorophyll fluorescence maxima were associated with the cool filament core, but elevated levels were also associated with the low-salinity, slightly warmer water on the outer edge of the filament along its entire track. Subduction within the filament resulted in elevated chlorophyll concentrations extending to approximately 100 m depth, nearly twice the estimated euphotic zone depth. Phytoplankton taxa within the filament were characteristic of those found within coastal upwelling regions. As was expected, the cyclonic eddy contained high salinity and high nutrient concentrations, but temperature at the surface was higher than was expected for the salinity, suggesting that there was little horizontal exchange between the cyclone and the cool filament and that the high-salinity water may have originated from local (open ocean) upwelling or it may have been displaced seaward from a near-coast origin several weeks earlier. The seaward jet associated with the filament resulted in a large transport of nutrients and phytoplankton biomass offshore, but the shoreward flow, downstream from the cyclonic bend, reduced the net transport to the offshore region. Shoreward nitrate transport was 85 to 90% of seaward transport, similar in proportion to the shoreward volume transport (approximately 90%) relative to the seaward volume transport. In contrast, shoreward chlorophyll transport was about 40% of seaward transport, indicating that the meandering jet may supply significant phytoplankton biomass to the offshore region. The meandering jet and filament system had a clear imprint on the chemical and biological structure of the region. This structure has implications to the fluxes of organic material in the region and it is probably significant in organizing the interactions among different trophic levels within the system. C1 UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,MIAMI,FL 33149. NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771. USN,POSTGRAD SCH,DEPT OCEANOG,MONTEREY,CA 93943. UNIV CALIF SANTA BARBARA,DEPT GEOG,SANTA BARBARA,CA 93106. RP JONES, BH (reprint author), UNIV SO CALIF,DEPT BIOL SCI,ALLAN HANCOCK FDN,ROOM 107,LOS ANGELES,CA 90089, USA. NR 36 TC 25 Z9 25 U1 0 U2 6 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 DEC 15 PY 1991 VL 96 IS C12 BP 22207 EP 22225 DI 10.1029/91JC02146 PG 19 WC Oceanography SC Oceanography GA GW576 UT WOS:A1991GW57600019 ER PT J AU MISRA, AK AF MISRA, AK TI THERMOCHEMICAL ANALYSIS OF CHEMICAL PROCESSES RELEVANT TO THE STABILITY AND PROCESSING OF SIC-REINFORCED SI3N4 COMPOSITES SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SILICON-NITRIDE; VOLATILIZATION AB Chemical processes relevant to the stability and processing of SiC-reinforced Si3N4 composites are examined from a thermochemical point of view. The thermodynamic stability of various interfaces, such as SiC-Si3N4, SiC-Si3N4-Si2ON2, and SiC-Si3N4-SiO2, is examined as a function of temperature. The temperatures above which these interfaces become unstable are calculated, and the degradation of SiC during the processing of the composite is examined. The processing routes considered in this study include the reaction-bonded silicon nitride process, as well as pressure-assisted sintering processes in the presence of suitable sintering additives. RP MISRA, AK (reprint author), NASA,SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,CLEVELAND,OH 44135, USA. NR 17 TC 7 Z9 7 U1 1 U2 2 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 DEC 15 PY 1991 VL 26 IS 24 BP 6591 EP 6598 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA GX648 UT WOS:A1991GX64800009 ER PT J AU TURNER, NJ CRAM, LE ROBINSON, RD AF TURNER, NJ CRAM, LE ROBINSON, RD TI INHOMOGENEOUS STRUCTURE IN THE CHROMOSPHERES OF DWARF-M STARS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID STELLAR MODEL CHROMOSPHERES; H-ALPHA EMISSION; MAGNETIC-STRUCTURE; COOL STARS; ATMOSPHERES; PROFILES; FLUXES; LINES AB Linear combinations of observed spectra of the H-alpha and Ca II resonance and IR lines from the chromospheres of a quiet (Gl 1) and an active (Gl 735) dwarf M star have been compared with the corresponding spectra from a star of intermediate activity (Gl 887). It is shown that the intermediate spectra cannot be explained as a simple juxtaposition of the extreme chromospheric states. It is concluded that the range of observed strengths of chromospheric activity indicators in dwarf M stars is due, at least in part, to changes in the radial structure of the chromospheric heating function and not to changes in the area filling factor. C1 NASA,GODDARD SPACE FLIGHT CTR,CSC,GREENBELT,MD 20771. RP TURNER, NJ (reprint author), UNIV SYDNEY,SCH PHYS,SYDNEY,NSW 2006,AUSTRALIA. RI Cram, Lawrence/H-4059-2012 OI Cram, Lawrence/0000-0002-8096-447X NR 21 TC 2 Z9 2 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 DEC 15 PY 1991 VL 253 IS 4 BP 575 EP 578 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GV327 UT WOS:A1991GV32700002 ER PT J AU MOORHOUSE, A BRAND, PWJL GEBALLE, TR BURTON, MG AF MOORHOUSE, A BRAND, PWJL GEBALLE, TR BURTON, MG TI SURPRISINGLY HIGH-PRESSURE SHOCKS IN THE SUPERNOVA REMNANT IC-443 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID MOLECULAR-HYDROGEN; NOVA REMNANT; LINE EMISSION; REGION; CLOUDS; WAVES; ORION; H-2 AB The intensities of several lines of molecular hydrogen have been measured from two regions of the supernova-remnant/molecular-cloud shock in IC443. The lines measured have upper-state energies ranging from 7000 K to 23 000 K. Their relative intensities differ in the two regions, but are consistent with those predicted from the post-shock regions of simple jump-type shocks of different pressure. The pressures so derived are far higher than the pressure in the supernova remnant itself, and a possible reason for this discrepancy is discussed. C1 ROYAL OBSERV,DEPT ASTRON,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. JOINT ASTRON CTR,HILO,HI 96720. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF IRVINE,IRVINE,CA 92717. RP MOORHOUSE, A (reprint author), DUBLIN INST ADV STUDIES,SCH COSM PHYS,5 MERRION SQ,DUBLIN 2,IRELAND. NR 29 TC 16 Z9 16 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 DEC 15 PY 1991 VL 253 IS 4 BP 662 EP 668 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GV327 UT WOS:A1991GV32700013 ER PT J AU OWENS, A PASCARELLE, SM GEHRELS, N TEEGARDEN, BJ AF OWENS, A PASCARELLE, SM GEHRELS, N TEEGARDEN, BJ TI EMPIRICAL EFFICIENCY AND VOLUME RELATIONSHIPS FOR HPGE DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID GE(LI) AB We have extended the empirical work of Vano et al. [1] relating the slope of the detector efficiency curve to the active volume for Ge detectors. The analysis was carried out using Monte Carlo techniques and covered a wide range of incident energies (200 keV-20 MeV) and active volumes (19.6 cm3-396 cm3). It is shown that the expression of Vano et al. [1] is only valid over the energy range approximately 200 keV-3 MeV for active volumes < 50 cm3. The upper bound decreases to approximately 2 MeV for volumes of a few hundred cm3. The usable energy range can, however, be extended to 6 MeV by introducing higher order terms into the polynomial. Above this energy, the shape of the efficiency curve is better described by a non-linear function since linear forms fail simultaneously to fit large active volumes and high energies. We therefore propose a composite function which reduces to the form given in Vano et al. in the low energy/active volume limit. By comparison with the Monte Carlo results, it is estimated that relative efficiencies can be calculated to within approximately 6% over the energy range 200 keV-20 MeV and active volumes 20 cm3-400 cm3. Since the largest errors occur for the smallest volumes. We recommend that for energies < 3 MeV a two-fold approach be followed, i.e. using the expression of Vano et al. [1] for active volumes less than 50 cm3 and the proposed non-linear form for larger volumes. For high energy work (E > 3 MeV), we advocate the non-linear form. In this way, average errors can be kept < 3%. Finally, we point out that the real power of the expression of Vano et al. lies not in predicting efficiencies, but active volumes. RP OWENS, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Gehrels, Neil/D-2971-2012 NR 8 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 15 PY 1991 VL 310 IS 3 BP 681 EP 684 DI 10.1016/0168-9002(91)91117-E PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GV086 UT WOS:A1991GV08600015 ER PT J AU TURNER, MS AF TURNER, MS TI TILTED UNIVERSE AND OTHER REMNANTS OF THE PREINFLATIONARY UNIVERSE SO PHYSICAL REVIEW D LA English DT Article ID COSMIC BACKGROUND-RADIATION; LARGE-SCALE ANISOTROPY; ELLIPTICAL GALAXIES; INFLATIONARY UNIVERSE; SUPERGALACTIC CENTER; INVISIBLE AXION; SPECTROSCOPY; PHOTOMETRY; FLUCTUATIONS; COSMOLOGY AB If the inflationary epoch lasted only approximately 10 e-foldings longer than required to solve the horizon problem, observable "remnants" of the preinflationary Universe may exist. They include dipole and quadrupole anisotropies of the cosmic microwave background radiation (CMBR). These "remnants" arise due to preinflationary fluctuations in scalar fields such as the inflaton, the axion, and the ilion, or due to preinflationary density perturbations. The dipole anisotropy can lead to the illusion of a "tilted universe": Viewed from the rest frame of the CMBR galaxies throughout the entire observable Universe would have a uniform streaming velocity. A dipole CMBR anisotropy could provide a very unconventional explanation for the large peculiar velocities measured for galaxies in our approximately 50h-1 Mpc neighborhood. Among things very unlikely to be a "remnant" of inflation is a value of OMEGA today that is significantly different from unity. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS & ASTRON,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTROPHYS,CHICAGO,IL 60637. RP TURNER, MS (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 32 TC 80 Z9 79 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 DEC 15 PY 1991 VL 44 IS 12 BP 3737 EP 3748 DI 10.1103/PhysRevD.44.3737 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GX138 UT WOS:A1991GX13800004 ER PT J AU ROULET, E AF ROULET, E TI E6 LEPTOQUARKS AND THE SOLAR-NEUTRINO PROBLEM SO PHYSICAL REVIEW D LA English DT Note ID OSCILLATIONS; MATTER AB The possibility that nonconventional neutrino oscillations take place in the superstring-inspired E6 models is considered. In this context, the influence of leptoquark-mediated interactions of the neutrinos with nucleons in the resonant flavor conversion is discussed. It is shown that this effect can be significant for nu-e-nu-tau oscillations if these neutrinos have the masses required in the ordinary Mikheyev-Smirnov-Wolfenstein effect, and may lead to a solution of the solar-neutrino problem even in the absence of vacuum mixings. On the other hand, this model cannot lead to resonant behavior in the Sun if the neutrinos are massless. RP ROULET, E (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 1991 VL 44 IS 12 BP 3971 EP 3973 DI 10.1103/PhysRevD.44.3971 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GX138 UT WOS:A1991GX13800033 ER PT J AU OCONNOR, DB SCOTT, GW COULTER, DR YAVROUIAN, A AF OCONNOR, DB SCOTT, GW COULTER, DR YAVROUIAN, A TI TEMPERATURE-DEPENDENCE OF ELECTRONIC-ENERGY TRANSFER AND QUENCHING IN COPOLYMER FILMS OF STYRENE AND 2-(2'-HYDROXY-5'-VINYLPHENYL)-2H-BENZOTRIAZOLE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ULTRAVIOLET STABILIZERS; PROTON-TRANSFER; MIGRATION; POLYSTYRENE; 2-(2'-HYDROXY-5'-METHYLPHENYL)-BENZOTRIAZOLE; POLYMERS; DEACTIVATION; PHOTOPHYSICS; TRANSPORT; KINETICS AB Quenching of the emission of both the polystyrene monomer and the excimer for a series of varying composition copolymer films of styrene and 2-(2'-hydroxy-5'-vinylphenyl)-2H-benzotriazole is reported. The preponderance of quenching for both the monomer and excimer emissions is due to interception of the migrating excitation at the quencher site, although additional quenching results via long-range dipole-dipole energy transfer from the monomer and excimer traps to the quencher trap. The quenching of the monomer fluorescence and phosphorescence and that of the excimer fluorescence were found to be temperature independent over the ranges 14-58 and 191-296 K, respectively. Most significantly, it is concluded that the energy migration process is temperature independent over the range 14-296 K. C1 UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521. CALTECH,JET PROP LAB,SPACE MAT SCI & TECHNOL SECT,PASADENA,CA 91109. RP SCOTT, GW (reprint author), UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521, USA. NR 48 TC 45 Z9 46 U1 2 U2 3 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 DEC 12 PY 1991 VL 95 IS 25 BP 10252 EP 10261 DI 10.1021/j100178a007 PG 10 WC Chemistry, Physical SC Chemistry GA GU911 UT WOS:A1991GU91100007 ER PT J AU HICKEY, GS AF HICKEY, GS TI EFFECT OF ELECTRON-RADIATION ON POLYMER MATRIX SYSTEMS SO THERMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT 19TH CONF OF THE NORTH AMERICAN THERMAL ANALYSIS SOC : INTERNATIONAL THERMAL ANALYSIS AND RESEARCH TRENDS CY SEP 23-26, 1990 CL BOSTON, MA SP N AMER THERMAL ANAL SOC AB The use of graphite-polymer composite materials in space is increasing in the number of applications and system requirements. A primary concern for any polymeric material for use in space is its environmental durability, particularly its mechanical properties. One well-documented space environmental concern is degradation by electron radiation because electrons have a high penetration ability and high natural flux rate in the space environment near the earth. Three polymer composite matrix systems were evaluated: a styrene butadiene rubber (SBR) toughened polycyanate, a carboxy terminated butyl nitrile (CTBN) toughened epoxy and a PES toughened epoxy/dicyanate. The resin systems were evaluated at electron radiation levels of zero control, 10 Mrad and 1000 Mrad total dose to evaluate changes in their glass transition, linear thermal expansion and dynamic modulus. Properties of the pure matrix were measured from -100-degrees-C to the glass transition temperature. RP HICKEY, GS (reprint author), CALTECH,JET PROP LAB,SPACE MAT SCI & ENGN SECT,PASADENA,CA 91109, USA. NR 9 TC 0 Z9 0 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD DEC 12 PY 1991 VL 192 BP 199 EP 208 DI 10.1016/0040-6031(91)87162-P PG 10 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA GX538 UT WOS:A1991GX53800022 ER PT J AU DAHLBURG, RB ANTIOCHOS, SK ZANG, TA AF DAHLBURG, RB ANTIOCHOS, SK ZANG, TA TI DYNAMICS OF SOLAR CORONAL MAGNETIC-FIELDS SO ASTROPHYSICAL JOURNAL LA English DT Article DE HYDROMAGNETICS; SUN, CORONA; SUN, MAGNETIC FIELDS ID MAGNETOHYDRODYNAMIC TURBULENCE; CURRENT SHEETS; PROMINENCES; MODEL; RECONNECTION; EVOLUTION; ERUPTION; REGIONS; ENERGY; FLARES AB Many aspects of solar activity are believed to be due to the stressing of the coronal magnetic field by footpoint motions at the photosphere. We present the results of a numerical simulation which, to our knowledge, is the first three-dimensional time-dependent simulation of footpoint stressing in a geometry appropriate for the corona. The numerical code generalizes to dissipative, incompressible MHD, a time-split method previously used for Navier-Stokes flows in channel geometry by Zang and Hussaini. We discretize space by a Fourier-Chebyshev collocation method, with a staggered grid used to avoid imposition of pressure boundary conditions. The velocity-vector potential intermediate step is performed with a low-storage third-order Runge-Kutta-Crank-Nicolson scheme. We consider an arcade that is initially current-free and impose a smooth footpoint motion that produces a twist in the field of approximately 2-pi. We then stop the photospheric motion and follow the evolution until the field relaxes, primarily by resistive diffusion, to another current-free state. We see no evidence for any instability, either ideal or resistive, during the complete simulation, and no evidence for current-sheet formation. The most striking feature of the evolution is that, in response to photospheric motions, the field expands rapidly upward to minimize the stress. We conclude that the expansion has two important effects. First, it suppresses the development of "dips" in the field that would be capable of supporting dense, cool material. At least for the motions that we assume, the magnetic field does not develop a geometry suitable for explaining prominence formation. Second, the expansion inhibits ideal instabilities such as kinking. Our results indicate that simple shearing of a single arcade is unlikely to lead to any significant manifestation of solar activity such as flares or prominences. We discuss effects that have not been included in the simulation and may possibly lead to such activity. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP DAHLBURG, RB (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. RI Antiochos, Spiro/D-4668-2012 OI Antiochos, Spiro/0000-0003-0176-4312 NR 36 TC 23 Z9 23 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 DEC 10 PY 1991 VL 383 IS 1 BP 420 EP 430 DI 10.1086/170799 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT975 UT WOS:A1991GT97500042 ER PT J AU WIEDEMANN, G BJORAKER, GL JENNINGS, DE AF WIEDEMANN, G BJORAKER, GL JENNINGS, DE TI DETECTION OF C-13-ETHANE IN JUPITER ATMOSPHERE SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SPECTRA; PLANETS, ABUNDANCES; PLANETS, ATMOSPHERE; PLANETS, JUPITER; PLANETS, SPECTRA ID C-12-C-13 RATIO; ETHANE AB High-resolution C-12- and C-13-ethane spectra of Jupiter were acquired with the Kitt Peak 4 m Fourier spectrometer and the Goddard postdisperser in 1987 June. A relative abundance ratio C-12/C-13 of 94 +/- 12 was derived from the measurements. This nearly terrestrial value indicates little or no fractionation of carbon isotopes when ethane is produced in the photolysis of methane in Jupiter's atmosphere. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,GREENBELT,MD 20771. RI Jennings, Donald/D-7978-2012 NR 11 TC 9 Z9 9 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 DEC 10 PY 1991 VL 383 IS 1 BP L29 EP L32 DI 10.1086/186233 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT976 UT WOS:A1991GT97600007 ER PT J AU LYZENGA, GA RAEFSKY, A MULLIGAN, SG AF LYZENGA, GA RAEFSKY, A MULLIGAN, SG TI MODELS OF RECURRENT STRIKE-SLIP EARTHQUAKE CYCLES AND THE STATE OF CRUSTAL STRESS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SAN-ANDREAS FAULT; SOUTHERN-CALIFORNIA; HALF-SPACE; ASTHENOSPHERE; DEFORMATION; LITHOSPHERE; DEPTH; PARKFIELD; FRICTION; RHEOLOGY AB Numerical models of the strike-slip earthquake cycle, assuming a viscoelastic asthenosphere coupling model, are examined. The time-dependent simulations incorporate a stress-driven fault, which leads to tectonic stress fields and earthquake recurrence histories that are mutually consistent. Single-fault simulations with constant far-field plate motion lead to a nearly periodic earthquake cycle and a distinctive spatial distribution of crustal shear stress. The predicted stress distribution includes a local minimum in stress at depths less than typical seismogenic depths. The width of this stress "trough" depends on the magnitude of crustal stress relative to asthenospheric drag stresses. The models further predict a local near-fault stress maximum at greater depths, sustained by the cyclic transfer of strain from the elastic crust to the ductile asthenosphere. Models incorporating both low-stress and high-stress fault strength assumptions are examined, under Newtonian and non-Newtonian rheology assumptions. Model results suggest a preference for low-stress (a shear stress level of approximately 10 MPa) fault models, in agreement with previous estimates based on heat flow measurements and other stress indicators. RP CALTECH, JET PROP LAB, M-S 238-332, PASADENA, CA 91109 USA. NR 39 TC 33 Z9 33 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 DEC 10 PY 1991 VL 96 IS B13 BP 21623 EP 21640 DI 10.1029/91JB02260 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GW578 UT WOS:A1991GW57800012 ER PT J AU VITTA, S STAN, MA WARNER, JD ALTEROVITZ, SA AF VITTA, S STAN, MA WARNER, JD ALTEROVITZ, SA TI MAGNETIC-FLUX RELAXATION IN YBA2CU3O7-X THIN-FILM - THERMAL OR ATHERMAL SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 18TH INTERNATIONAL CONF ON METALLURGICAL COATINGS AND THIN FILMS CY APR 22-26, 1991 CL SAN DIEGO, CA ID HIGH-TEMPERATURE SUPERCONDUCTORS; CRITICAL CURRENTS; CREEP; DEPENDENCE; FIELD AB The magnetic flux relaxation behavior of YBa2Cu3O7-x thin film on LaA1O3, for H parallel-to c was studied in the range 4.2 - 40 K and 0.2 - 1.0 T. Both the normalized flux relaxation rate S and the net flux pinning energy U increase continuously from 1.3 x 10(-2) to 3.0 x 10(-2) and from 70 to 240 meV respectively, as the temperature T increases from 10 to 40 K. This behavior is consistent with the thermally activated flux motion model. At low temperatures, however, S is found to decrease much more slowly as compared with kT, in contradiction to the thermal activation model. This behavior is discussed in terms of the athermal quantum tunneling of flux lines. The magnetic field dependence of U. however, is not completely understood. RP VITTA, S (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. RI Vitta, Satish/K-7336-2015 OI Vitta, Satish/0000-0003-4138-0022 NR 19 TC 0 Z9 0 U1 0 U2 1 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 DEC 10 PY 1991 VL 206 IS 1-2 BP 137 EP 142 DI 10.1016/0040-6090(91)90408-P PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA GZ322 UT WOS:A1991GZ32200025 ER PT J AU SYNOWICKI, R KUBIK, RD HALE, JS PETERKIN, J NAFIS, S WOOLLAM, JA ZAAT, S AF SYNOWICKI, R KUBIK, RD HALE, JS PETERKIN, J NAFIS, S WOOLLAM, JA ZAAT, S TI OXYGEN PLASMA ASHING EFFECTS ON ALUMINUM AND TITANIUM SPACE PROTECTIVE COATINGS SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 18TH INTERNATIONAL CONF ON METALLURGICAL COATINGS AND THIN FILMS CY APR 22-26, 1991 CL SAN DIEGO, CA AB Using variable angle spectroscopic ellipsometry and atomic force microscopy (AFM), the surface roughness and oxidation of aluminum and titanium thin films have been studied as a function of substrate deposition temperature and oxygen plasma exposure. Increasing substrate deposition temperatures affect film microstructure by greatly increasing grain size. Short exposures to an oxygen plasma environment produce sharp spikes rising rapidly above the surface as seen by AFM. Ellipsometric measurements were made over a wide range of plasma exposure times, and results at longer exposure times suggest that the surface is greater than 30% void. This is qualitatively verified by the AFM images. C1 UNIV NEBRASKA,DEPT ELECT ENGN,LINCOLN,NE 68588. NASA,CTR COMMERCIAL DEV SPACE,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP SYNOWICKI, R (reprint author), UNIV NEBRASKA,CTR ELECTROOPT,CTR MICROELECTR & OPT MAT RES,LINCOLN,NE 68588, USA. NR 4 TC 8 Z9 8 U1 1 U2 3 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 DEC 10 PY 1991 VL 206 IS 1-2 BP 254 EP 258 DI 10.1016/0040-6090(91)90431-V PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA GZ322 UT WOS:A1991GZ32200048 ER PT J AU ALTEROVITZ, SA SIEG, RM YAO, HD SNYDER, PG WOOLLAM, JA PAMULAPATI, J BHATTACHARYA, PK SEULAMOISE, PA AF ALTEROVITZ, SA SIEG, RM YAO, HD SNYDER, PG WOOLLAM, JA PAMULAPATI, J BHATTACHARYA, PK SEULAMOISE, PA TI STUDY OF INGAAS-BASED MODULATION DOPED FIELD-EFFECT TRANSISTOR STRUCTURES USING VARIABLE-ANGLE SPECTROSCOPIC ELLIPSOMETRY SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 18TH INTERNATIONAL CONF ON METALLURGICAL COATINGS AND THIN FILMS CY APR 22-26, 1991 CL SAN DIEGO, CA ID INP; HETEROSTRUCTURES; GAAS; GAP AB Variable-angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InGaAs-based modulation doped field effect transistor structures. Strained and unstrained InGaAs channels were made by molecular beam epitaxy (MBE) on InP substrates and by metal-organic chemical vapor deposition on GaAs substrates. In most cases, ellipsometrically determined thicknesses were within 10%. of the growth-calibration results. The MBE-made InGaAs strained layers showed large strain effects, indicating a probable shift in the critical points of their dielectric function toward the InP lattice-matched concentration. C1 CLEVELAND STATE UNIV,DEPT ELECT ENGN,CLEVELAND,OH 44115. UNIV NEBRASKA,DEPT ELECT ENGN,LINCOLN,NE 68588. SPIRE CORP,BEDFORD,MA 01730. RP ALTEROVITZ, SA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 18 TC 5 Z9 5 U1 1 U2 3 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 DEC 10 PY 1991 VL 206 IS 1-2 BP 288 EP 293 DI 10.1016/0040-6090(91)90437-3 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA GZ322 UT WOS:A1991GZ32200054 ER PT J AU LARSSON, A MASERJIAN, J AF LARSSON, A MASERJIAN, J TI OPTICALLY ADDRESSED ASYMMETRIC FABRY-PEROT MODULATOR SO APPLIED PHYSICS LETTERS LA English DT Article ID I-P-I; SPATIAL LIGHT MODULATORS; REFLECTION MODULATORS; MQW STRUCTURES; DEVICES AB A low power, high contrast optically addressed modulator, operating with normal incidence, has been fabricated. Optically controlled reflection modulation is achieved through optically induced absorption modulation in a periodically delta-doped InGaAs/GaAs multiple quantum well structure inserted in an integrated asymmetric Fabry-Perot resonator. A contrast ratio > 60:1 was measured using a spectrally matched low power InGaAs/GaAs quantum well laser to generate the write (control) signal. The insertion loss for the normally off modulator is 4.6 dB at the highest write signal power (30 mW) used. The device lends itself to the fabrication of arrays for optically addressed spatial light modulation. RP LARSSON, A (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 20 TC 18 Z9 18 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 DEC 9 PY 1991 VL 59 IS 24 BP 3099 EP 3101 DI 10.1063/1.105805 PG 3 WC Physics, Applied SC Physics GA GT899 UT WOS:A1991GT89900009 ER PT J AU LEOVY, CB FRIEDSON, AJ ORTON, GS AF LEOVY, CB FRIEDSON, AJ ORTON, GS TI THE QUASIQUADRENNIAL OSCILLATION OF JUPITER EQUATORIAL STRATOSPHERE SO NATURE LA English DT Article ID QUASI-BIENNIAL OSCILLATION; SEMIANNUAL OSCILLATION; MIDDLE ATMOSPHERE; EVOLUTION; WAVES; CYCLE; MODEL AB A NEW 11-year record of Jupiter's stratospheric temperature 1 shows an equatorial temperature oscillation with an apparent period of 4-5 years. Here we compare this oscillation to two long-period oscillations of zonal winds in the Earth's equatorial stratosphere, and propose that the same mechanism-forcing by the stresses of vertically propagating waves-is responsible for the oscillations on both planets. Jupiter's temperature oscillation has been observed for slightly more than two cycles and closely resembles the temperature signatures of the Earth's semiannual oscillation and quasibiennial oscillation. If the mechanisms responsible for these oscillations are indeed similar, Jupiter's oscillation indicates that there is significant vertical momentum transport due to equatorially trapped atmospheric waves, and it may provide a means for probing the poorly understood process of the generation of these waves by convection 2,3. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP LEOVY, CB (reprint author), UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195, USA. NR 15 TC 55 Z9 55 U1 0 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD DEC 5 PY 1991 VL 354 IS 6352 BP 380 EP 382 DI 10.1038/354380a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GT761 UT WOS:A1991GT76100046 ER PT J AU MCGUCKIN, BT MENZIES, RT HEMMATI, H AF MCGUCKIN, BT MENZIES, RT HEMMATI, H TI EFFICIENT ENERGY EXTRACTION FROM A DIODE-PUMPED Q-SWITCHED TM,HO-YLIF4 LASER SO APPLIED PHYSICS LETTERS LA English DT Article AB The operation of a diode-laser pumped thulium, holmium yttrium-lithium-fluoride laser (Tm,Ho:YLF) in Q-switched mode is reported. Output energies of 220-mu-J in pulses of 22 ns duration are recorded at Q-switch frequencies commensurate with an effective upper laser level lifetime of 6 ms. This lifetime is appreciably longer than that observed in other hosts permitting stored energy extraction of 64%, close to the projected maximum performance from these materials. RP MCGUCKIN, BT (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 15 TC 40 Z9 42 U1 2 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 2 PY 1991 VL 59 IS 23 BP 2926 EP 2928 DI 10.1063/1.105850 PG 3 WC Physics, Applied SC Physics GA GT017 UT WOS:A1991GT01700002 ER PT J AU KROGH, FT VANSNYDER, W AF KROGH, FT VANSNYDER, W TI ALGORITHM-699 - A NEW REPRESENTATION OF PATTERSON QUADRATURE-FORMULAS SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE ALGORITHMS ID GENERAL WEIGHT-FUNCTIONS; PREASSIGNED NODES; HIGHEST DEGREE; PRECISION; RULES AB A method is presented to reduce the number of coefficients necessary to represent Patterson's quadrature formulae, to reduce the amount of storage necessary for storing function values, and to produce slightly smaller error in evaluating the formulae. C1 JET PROP LAB,PASADENA,CA 91109. NR 6 TC 9 Z9 9 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD DEC PY 1991 VL 17 IS 4 BP 457 EP 461 DI 10.1145/210232.210235 PG 5 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA KZ399 UT WOS:A1991KZ39900003 ER PT J AU HORNSTEIN, RS SHINKLE, GL WEILER, JD WILLOUGHBY, JK AF HORNSTEIN, RS SHINKLE, GL WEILER, JD WILLOUGHBY, JK TI AN INNOVATIVE APPROACH FOR DISTRIBUTED AND INTEGRATED RESOURCES PLANNING FOR THE SPACE STATION FREEDOM SO ACTA ASTRONAUTICA LA English DT Article AB The widely distributed nature of the Space Station Freedom program, plus continuous multi-year operations will force program planners to develop innovative planning concepts. The traditional centralized planning operation will not be adequate. It will be replaced by multiple small planning centers working within guidelines issued by a central planning authority. Plans will not be optimized; rather, operating efficiency and user flexibility will be blended to satisfy program goals. The key to this new approach is the application of new planning methodologies and system development technologies to accommodate distributed resources that must be integrated. Resources will be distributed to the multiple planning entities in such a way that, when the several plans are built and then integrated, they will fit together with minimal modification. The plan itself will be an envelope schedule containing resource limits and constraint boundaries within which users will be free to make choices of the specific activities they will execute, up to the time of execution. Some level of margin within program guidelines will be built in to allow for variation and unforeseen change. This paper presents the authors' recommended planning approach and cites two NASA systems being developed that will utilize these resource distribution/integration planning concepts, methodologies and development technologies. RP HORNSTEIN, RS (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 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 DEC PY 1991 VL 25 IS 12 BP 793 EP 798 DI 10.1016/0094-5765(91)90058-D PG 6 WC Engineering, Aerospace SC Engineering GA GY682 UT WOS:A1991GY68200007 ER PT J AU SOMMER, K BATOULIS, J JILGE, W MORBITZER, L PITTEL, B PLAETSCHKE, R REUTER, K TIMMERMANN, R BINDER, K PAUL, W GENTILE, FT HEERMANN, DW KREMER, K LASO, M SUTER, UW LUDOVICE, PJ AF SOMMER, K BATOULIS, J JILGE, W MORBITZER, L PITTEL, B PLAETSCHKE, R REUTER, K TIMMERMANN, R BINDER, K PAUL, W GENTILE, FT HEERMANN, DW KREMER, K LASO, M SUTER, UW LUDOVICE, PJ TI CORRELATION BETWEEN PRIMARY CHEMICAL-STRUCTURE AND PROPERTY PHENOMENA IN POLYCONDENSATES SO ADVANCED MATERIALS LA English DT Article ID MECHANICAL-PROPERTIES; POLYCARBONATES; DYNAMICS; VISCOSITY; POLYMERS; NMR AB Systematic variation and theoretical simulation of materials belonging to the above mentioned particular group of polycondensates provide the opportunity for the acquisition of a better understanding of the relationships between the chemical structure and corresponding physical and technical properties of the polymers. The work described here has therefore been devoted to the polymers of this group. C1 TH ZURICH, ZURICH, SWITZERLAND. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. CELLULAR TRANSPLANTS INC, PROVIDENCE, RI USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, W-5170 JULICH 1, GERMANY. UNIV MAINZ, W-6500 MAINZ, GERMANY. UNIV HEIDELBERG, W-6900 HEIDELBERG, GERMANY. RP SOMMER, K (reprint author), BAYER AG, CENT RES, W-5090 LEVERKUSEN, GERMANY. RI Kremer, Kurt/G-5652-2011; Suter, Ulrich/H-8900-2013; Laso, Manuel/H-2734-2015 OI Suter, Ulrich/0000-0001-7467-7346; NR 30 TC 18 Z9 19 U1 1 U2 1 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD DEC PY 1991 VL 3 IS 12 BP 590 EP 599 DI 10.1002/adma.19910031204 PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA GX212 UT WOS:A1991GX21200002 ER PT J AU GALLMAN, JM MYERS, MK FARASSAT, F AF GALLMAN, JM MYERS, MK FARASSAT, F TI BOUNDARY INTEGRAL APPROACH TO THE SCATTERING OF NONPLANAR ACOUSTIC-WAVES BY RIGID BODIES SO AIAA JOURNAL LA English DT Article AB The acoustic scattering of an incident wave by a rigid body can be described by a singular Fredholm integral equation of the second kind. This equation is derived by solving the wave equation using generalized function theory, Green's function for the wave equation in unbounded space, and the acoustic boundary condition for a perfectly rigid body. This paper discusses the derivation of the wave equation, its reformulation as a boundary integral equation, and the solution of the integral equation by the Galerkin method. The accuracy of the Galerkin method can be assessed by applying the technique outlined in the paper to reproduce the known pressure fields that are due to various point sources. From the analysis of these simpler cases, the accuracy of the Galerkin solution can be inferred for the scattered pressure field caused by the incidence of a dipole field on a rigid sphere. The solution by the Galerkin technique can then be applied to such problems as a dipole model of a propeller whose pressure field is incident on a rigid cylinder. This is the groundwork for modeling the scattering of rotating blade noise by airplane fuselages. C1 GEORGE WASHINGTON UNIV,JOINT INST ADVANCEMENT FLIGHT SCI,WASHINGTON,DC 20052. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP GALLMAN, JM (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 13 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 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1991 VL 29 IS 12 BP 2038 EP 2046 DI 10.2514/3.10839 PG 9 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200005 ER PT J AU DEGANI, D SCHIFF, LB LEVY, Y AF DEGANI, D SCHIFF, LB LEVY, Y TI NUMERICAL PREDICTION OF SUBSONIC TURBULENT FLOWS OVER SLENDER BODIES AT HIGH-INCIDENCE SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 28TH MEETING ON AEROSPACE SCIENCES CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT ID VORTICAL FLOWS; OGIVE-CYLINDER; SIMULATION AB The physical aspects governing accurate numerical simulation of turbulent flows having large regions of crossflow separation are re-examined. Time-accurate, three-dimensional fine-grid Navier-Stokes solutions were obtained for turbulent subsonic flows over a slender ogive-cylinder body of revolution at large angles of attack. These flowfields are complex and contain regions of crossflow separation and an organized leeward-side vortex structure. An algebraic eddy-viscosity turbulence model has been modified to correctly account for the effects of the vortices on the underlying viscous layers. The numerical results show that the vortical flow structure of subsonic and supersonic high-incidence flows are similar, and can be accurately treated by the modified turbulence model. As the angle of attack is increased, the effectiveness of the model increases since the influence of the vortices on the underlying boundary layer decreases. C1 NASA,AMES RES CTR,DIV FLUID DYNAM,MOFFETT FIELD,CA 94035. RP DEGANI, D (reprint author), TECHNION ISRAEL INST TECHNOL,FAC MECH ENGN,IL-32000 HAIFA,ISRAEL. NR 26 TC 10 Z9 10 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 DEC PY 1991 VL 29 IS 12 BP 2054 EP 2061 DI 10.2514/3.10841 PG 8 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200007 ER PT J AU SO, RMC ZHANG, HS SPEZIALE, CG AF SO, RMC ZHANG, HS SPEZIALE, CG TI NEAR-WALL MODELING OF THE DISSIPATION RATE-EQUATION SO AIAA JOURNAL LA English DT Article ID LOW-REYNOLDS-NUMBER; CONVECTIVE HEAT-TRANSFER; COMPLEX TURBULENT FLOWS; DEVELOPED PIPE-FLOW; BOUNDARY-LAYER; SPECTRAL MEASUREMENTS; CHANNEL FLOW; COMPUTATION; STRESS AB Near-wall modeling of the dissipation rate equation is investigated and its asymptotic behavior is studied in detail using a k-epsilon model. It is found that all existing modeled dissipation rate equations predict an incorrect behavior for the dissipation rate near a wall. An improvement is proposed and the resulting near-wall dissipation rate distribution is found to be similar to that given by numerical simulation data. To further validate the improved k-epsilon model, it is used to calculate flat-plate turbulent boundary-layer flows at high- as well as low-turbulence Reynolds numbers, and the results are compared with measurements, numerical simulation data, and the calculations of three different two-equation models. These comparisons show that all the models tested give essentially the same flow properties away from the wall; significant differences only occur in a region very close to the wall. In this region, the calculations of the improved k-epsilon model are in better agreement with measurements and numerical simulation data. In particular, the modeled distribution of the dissipation rate is significantly improved and a maximum is predicted at the wall instead of away from the wall. Furthermore, the improved k-epsilon model is found to be the most asymptotically consistent among the four different two-equation models examined. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. RP SO, RMC (reprint author), ARIZONA STATE UNIV,MECH & AEROSP ENGN,TEMPE,AZ 85287, USA. RI So, Ronald/B-6698-2008 NR 29 TC 42 Z9 43 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 DEC PY 1991 VL 29 IS 12 BP 2069 EP 2076 DI 10.2514/3.10843 PG 8 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200009 ER PT J AU MAVRIPLIS, DJ AF MAVRIPLIS, DJ TI ALGEBRAIC TURBULENCE MODELING FOR UNSTRUCTURED AND ADAPTIVE MESHES SO AIAA JOURNAL LA English DT Article AB An algebraic turbulence model, based on the Baldwin-Lomax model, has been implemented for use on unstructured grids. The implementation is based on the use of local background turbulence meshes. At each time step, flow variables are interpolated from the unstructured mesh onto the background structured meshes, the turbulence model is executed on these meshes, and the resulting eddy viscosity values are interpolated back to the unstructured mesh. Modifications to the algebraic model were required to enable the treatment of more complicated flows, such as confluent boundary layers and wakes. The model is used in conjunction with an efficient unstructured multigrid finite-element Navier-Stokes solver, in order to compute compressible turbulent flows on fully unstructured meshes. Solutions about single and multiple element airfoils are obtained and compared with experimental data. RP MAVRIPLIS, DJ (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,MAIL STOP 132C,HAMPTON,VA 23665, USA. NR 18 TC 15 Z9 15 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 DEC PY 1991 VL 29 IS 12 BP 2086 EP 2093 DI 10.2514/3.10845 PG 8 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200011 ER PT J AU KANDIL, OA WONG, TC LIU, CH AF KANDIL, OA WONG, TC LIU, CH TI PREDICTION OF STEADY AND UNSTEADY ASYMMETRIC VORTICAL FLOWS AROUND CIRCULAR CONES SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 28TH MEETING ON AEROSPACE SCIENCES CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB Steady and unsteady, supersonic asymmetric vortical flows and their passive control around circular cones are considered in this paper. These problems are formulated by using the unsteady, compressible, single and double, thin-layer, Navier-Stokes equations. The equations are solved by using an implicit, upwind, flux-difference splitting, finite-volume scheme, either in a pseudotime stepping or in an accurate time stepping. An implicit, approximately factored, central-difference, finite-volume scheme has also been used to validate some applications of the upwind scheme. Local conical flows are assumed for the computational applications presented in this paper. Steady asymmetric vortical flows have been predicted by using random and controlled disturbances. Unsteady asymmetric vortex-shedding flows have also been predicted, for the first time, using time-accurate solutions with two different computational schemes. Control of flow asymmetry has been demonstrated computationally by inserting a vertical fin in the leeward plane of geometric symmetry. C1 NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. RP KANDIL, OA (reprint author), OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23529, USA. NR 22 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1991 VL 29 IS 12 BP 2169 EP 2178 DI 10.2514/3.10855 PG 10 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200021 ER PT J AU ANDERSON, WK AF ANDERSON, WK TI NUMERICAL STUDY ON USING SULFUR-HEXAFLUORIDE AS A WIND-TUNNEL TEST GAS SO AIAA JOURNAL LA English DT Article AB A NUMERICAL study is presented that investigates effects of using sulfur hexafluoride, SF6, as a substitute for air. Inviscid results for airfoils indicate that for transonic cases the shock location calculated for SF6 is vastly different from that in air and moves progressively forward on the airfoil as the freestream pressure is increased and real gas effects become more pronounced. Application of a simple Mach number scaling procedure results in good correlation between SF6 and air even for pressures at which nonideal gas effects are significant. Computations for subsonic turbulent flows over a NACA 0012 airfoil show that the maximum angle of attack at which steady lift can be obtained is different between air and SF6. In addition, for SF6, this angle of attack depends on the freestream conditions. Improved agreement with air can be achieved by altering the freestream Mach number according to the inviscid scaling procedure. Transonic results show that even with Mach number scaling, the shock location and skin friction values calculated between air and SF6 are in disagreement. This is attributed to the limitations of the scaling procedure and to a thinner boundary layer for SF6. RP ANDERSON, WK (reprint author), NASA,LANGLEY RES CTR,COMP AERODYM BRANCH,HAMPTON,VA 23665, USA. NR 10 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 DEC PY 1991 VL 29 IS 12 BP 2179 EP 2180 DI 10.2514/3.10856 PG 2 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200022 ER PT J AU THURSTON, GA SISTLA, R AF THURSTON, GA SISTLA, R TI ELIMINATION OF GIBBS PHENOMENA FROM ERROR ANALYSIS OF FINITE-ELEMENT RESULTS SO AIAA JOURNAL LA English DT Article ID ESTIMATOR AB A change of variables is presented that improves the accuracy of Fourier half-range sine series used in numerical harmonic analysis. The change in variables, a simple but effective extension of the period of the series, results in an interpolation formula that passes through the endpoints of tabulated data. In two dimensions, the change in variables produces an "extended grid" for use in computing coefficients in double sine series. The improved double sine series was developed for modifying a postprocessor code for error analysis of results from a general-purpose finite element code. Without going into the details of the error analysis, the paper illustrates the improved numerical harmonic analysis by applying it to the problem of a simply supported plate under uniform load. The elimination of Gibbs' phenomenon from the truncated series for the uniform load and from a discrete set of boundary conditions suggests that the extended grid transformation can be applied readily in a postprocessor for error analysis of discrete results for postbuckled stiffened panels. C1 ANALYT SERV MAT INC,HAMPTON,VA 23665. RP THURSTON, GA (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT MECH,STRUCT MECH BRANCH,MS-190,HAMPTON,VA 23665, USA. NR 11 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1991 VL 29 IS 12 BP 2233 EP 2239 DI 10.2514/3.10864 PG 7 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200030 ER PT J AU PRITCHARD, JI ADELMAN, HM AF PRITCHARD, JI ADELMAN, HM TI DIFFERENTIAL-EQUATION BASED METHOD FOR ACCURATE APPROXIMATIONS IN OPTIMIZATION SO AIAA JOURNAL LA English DT Article ID STRUCTURAL SYNTHESIS; CONSTRAINTS; DESIGN AB This paper describes a method to efficiently and accurately approximate the effect of design changes on structural response. The key to this new method is to interpret sensitivity equations as differential equations that may be solved explicitly for closed-form approximations, hence, the method is denoted the differential equation based (DEB) method. Approximations were developed for vibration frequencies, mode shapes, and static displacements. The DEB approximation method was applied to a cantilever beam and results compared with the commonly used linear Taylor series approximations and exact solutions. The test calculations involved perturbing the height, width, cross-sectional area, tip mass, and bending inertia of the beam. The DEB method proved to be very accurate, and in most cases, was more accurate than the linear Taylor series approximation. The method is applicable to simultaneous perturbation of several design variables. Also, the approximations may be used to calculate other system response quantities. For example, the approximations for displacements are used to approximate bending stresses. C1 NASA,LANGLEY RES CTR,INTERDISCIPLINARY RES OFF,HAMPTON,VA 23665. NR 14 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 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 1991 VL 29 IS 12 BP 2240 EP 2246 DI 10.2514/3.10865 PG 7 WC Engineering, Aerospace SC Engineering GA GX692 UT WOS:A1991GX69200031 ER PT J AU ENCRENAZ, T LELLOUCH, E ROSENQVIST, J DROSSART, P COMBES, M BILLEBAUD, F DEPATER, I GULKIS, S MAILLARD, JP PAUBERT, G AF ENCRENAZ, T LELLOUCH, E ROSENQVIST, J DROSSART, P COMBES, M BILLEBAUD, F DEPATER, I GULKIS, S MAILLARD, JP PAUBERT, G TI THE ATMOSPHERIC COMPOSITION OF MARS - ISM AND GROUND-BASED OBSERVATIONAL DATA SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID CARBON-MONOXIDE; STABILITY; ABUNDANCE; SPECTRA AB Monitoring the abundances of Martian minor constitutents and searching for local variations can provide valuable information about the aeronomy of the Martian atmosphere. Recent results from the PHOBOS ISM experiment suggest possible local variations of the carbon monoxide (CO) abundance. Additional constraints have been given by ground-based observations of CO in the infrared (IR) and millimeter range, a search for minor species in the millimeter range, and the millimeter detection of deuterated water (HDO). From these data, information on the thermal profile and the vertical distribution low CO and H2O has been retrieved. C1 OBSERV LYON,F-69561 ST GENIS LAVAL,FRANCE. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. CALTECH,JET PROP LAB,PASADENA,CA 91109. INST ASTROPHYS,F-75014 PARIS,FRANCE. IRAM,E-18012 GRANADA,SPAIN. RP ENCRENAZ, T (reprint author), OBSERV PARIS,F-92195 MEUDON,FRANCE. NR 29 TC 37 Z9 37 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD DEC PY 1991 VL 9 IS 12 BP 797 EP 803 PG 7 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA HF477 UT WOS:A1991HF47700004 ER PT J AU LADOUS, C AF LADOUS, C TI NEW INSIGHTS FROM A STATISTICAL-ANALYSIS OF IUE SPECTRA OF DWARF NOVAE AND NOVA-LIKE STARS .1. INCLINATION EFFECTS IN LINES AND CONTINUA SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE CLOSE BINARIES; CATACLYSMIC VARIABLES; ACCRETION DISKS; UV RADIATION ID ACCRETION DISKS; CATACLYSMIC VARIABLES; ULTRAVIOLET-SPECTRA; WHITE-DWARFS; Z-CHA; OUTBURST; ERUPTION; EMISSION; CATALOG; IMAGES AB IUE observations of dwarf novae and nova-like objects are analysed for effects of the inclination angle on the emitted continuum and line radiation. The investigations are restricted to dwarf novae at maximum and quiescence and to nova-like stars at the high brightness state. A clear pattern in the continuum flux distribution is exhibited only by dwarf novae at maximum where some 80 percent of the non-double-eclipsing systems show essentially identical distributions; this result is not in disagreement with theoretical expectations for stationary accretion disks. According to theoretical considerations, in the case of dwarf novae at quiescence and magnetic nova-like stars the lack of clear pattern was expected. Non-magnetic nova-like stars conventionally are considered as dwarf novae in a prolonged or permanent state of outburst which would suggest similar radiation patterns for both classes; however, observations tell that they are distinctly different concerning the continuum as well as the line radiation. All classes of objects exhibit a clear, but in each case different, dependence of the line radiation on the inclination angle. Approximate inclinations can be derived for objects where they were not known so far. C1 NASA, GODDARD SPACE FLIGHT CTR, NSSDC, GREENBELT, MD 20771 USA. UNIV CAMBRIDGE, INST ASTRON, CAMBRIDGE CB3 0HA, ENGLAND. RP LADOUS, C (reprint author), ESA IUE OBSERV, APARTADO 50727, E-28080 MADRID, SPAIN. NR 37 TC 77 Z9 77 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 DEC PY 1991 VL 252 IS 1 BP 100 EP 122 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT517 UT WOS:A1991GT51700017 ER PT J AU SCHMIEDER, B FONTENLA, J TANDBERGHANSSEN, E AF SCHMIEDER, B FONTENLA, J TANDBERGHANSSEN, E TI A MICROFLARE-RELATED ACTIVATION OF A FILAMENT OBSERVED IN H-ALPHA AND C-IV LINES SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE SUN, ACTIVITY OF; FACULAE; FLARES; PROMINENCES ID DISTURBED SOLAR FILAMENT; MAXIMUM MISSION; PROMINENCE; ERUPTION; REGION AB A filament in active region AR 2717 was observed in two lines formed at different temperatures (H-alpha at 10(4) K and C IV at 10(5) K) with the multi-channel-double-pass (MSDP) spectrograph and the ultraviolet spectrometer and polarimeter (UVSP). The partial disparition brusque (DB) of the filament as observed in H-alpha was due to the heating of a filament section in the vicinity of a bright point. A propagating disturbance followed this event. A detailed analysis of C IV rasters shows that this disturbance was not a passive perturbation, but was itself triggering active phenomena at various locations along its path, resulting in energy releases. We suggest that this propagation of brightness was due to fast successive reconnections between fine loop-like structures of the filament. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. RP SCHMIEDER, B (reprint author), OBSERV PARIS, MEUDON SECT, F-92195 MEUDON, FRANCE. NR 31 TC 13 Z9 14 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 DEC PY 1991 VL 252 IS 1 BP 343 EP 352 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT517 UT WOS:A1991GT51700044 ER PT J AU KAWAI, N MATSUOKA, M BREGMAN, JN ALLER, HD HUGHES, PA BALBUS, SA BALONEK, TJ CHAMBERS, KC CLEGG, RES CLEMENTS, SD LEACOCK, RJ SMITH, AG MILLER, JS HERELD, M HOARE, MG HUGHES, VA MILEY, GK MORIARTYSCHIEVEN, GH MATTHEWS, K NEUGEBAUER, G OHASHI, T ROCHE, PF THRONSON, HA VALTAOJA, E TERASRANTA, H WEBB, JR GOODRICH, R WILLS, BJ WILLS, D AF KAWAI, N MATSUOKA, M BREGMAN, JN ALLER, HD HUGHES, PA BALBUS, SA BALONEK, TJ CHAMBERS, KC CLEGG, RES CLEMENTS, SD LEACOCK, RJ SMITH, AG MILLER, JS HERELD, M HOARE, MG HUGHES, VA MILEY, GK MORIARTYSCHIEVEN, GH MATTHEWS, K NEUGEBAUER, G OHASHI, T ROCHE, PF THRONSON, HA VALTAOJA, E TERASRANTA, H WEBB, JR GOODRICH, R WILLS, BJ WILLS, D TI MULTIFREQUENCY OBSERVATIONS OF BL LACERTAE IN 1988 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL LACERTAE OBJECTS; INFRARED, SOURCES; RADIATION MECHANISMS; RADIO SOURCES, VARIABLE; X-RAYS, SPECTRA ID SPECTRUM; GINGA AB Simultaneous multiwavelength observations of BL Lacertae were performed on two occasions separated by 1 month in 1988 June and July, covering the radio, submillimeter, infrared, optical, ultraviolet, and X-ray wave bands. In the wide-band photon spectra, the X-ray flux lies clearly above the extension of radio-ultraviolet continuum as expected. The slope of the X-ray spectra is significantly flatter than that at optical-ultraviolet regimes, and its spectral index 0.7-1.0 corresponds to the slope at submillimeter band. Comparison with earlier observations, in fact, indicates that the X-ray flux is correlated with the submillimeter band, and not with the others, and supports the SSC model. C1 UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. UNIV VIRGINIA,DEPT ASTRON,CHARLOTTESVILLE,VA 22903. COLGATE UNIV,DEPT PHYS & ASTRON,HAMILTON,NY 13346. LEIDEN OBSERV,2300 RA LEIDEN,NETHERLANDS. ROYAL GREENWICH OBSERV,CAMBRIDGE CB3 0EZ,ENGLAND. UNIV FLORIDA,DEPT ASTRON,GAINESVILLE,FL 32611. UNIV CALIF SANTA CRUZ,LICK OBSERV,SANTA CRUZ,CA 95064. UNIV CHICAGO,CTR ASTRON & ASTROPHYS,CHICAGO,IL 60637. UNIV OXFORD,DEPT ASTROPHYS,NUCL PHYS LAB,OXFORD OX1 3RH,ENGLAND. QUEENS UNIV,DEPT PHYS,ASTRON GRP,KINGSTON K7L 3N6,ONTARIO,CANADA. CALTECH,JET PROP LAB,PASADENA,CA 91109. STERREWACHT,2300 RA LEIDEN,NETHERLANDS. CALTECH,PALOMAR OBSERV,PASADENA,CA 91125. UNIV TOKYO,DEPT PHYS,BUNKYO KU,TOKYO 113,JAPAN. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. UNIV WYOMING,DEPT PHYS & ASTRON,LARAMIE,WY 82071. HELSINKI UNIV TECHNOL,METSAHOVI RADIO RES STN,SF-02150 ESPOO,FINLAND. FLORIDA INT UNIV,DEPT PHYS,MIAMI,FL 33199. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. RP KAWAI, N (reprint author), INST PHYS & CHEM RES,2-1 HIROSAWA,WAKO,SAITAMA 35101,JAPAN. RI Thronson, Harley/E-3382-2012; OI Hereld, Mark/0000-0002-0268-2880; Roche, Patrick/0000-0002-8524-8413 NR 14 TC 26 Z9 26 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 DEC 1 PY 1991 VL 382 IS 2 BP 508 EP 514 DI 10.1086/170737 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR012 UT WOS:A1991GR01200012 ER PT J AU SCHUTTE, WA TIELENS, AGGM SANDFORD, SA AF SCHUTTE, WA TIELENS, AGGM SANDFORD, SA TI 10 MICRON SPECTRA OF PROTOSTARS AND THE SOLID METHANOL ABUNDANCE SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SPECTRA; INTERSTELLAR, GRAINS; INTERSTELLAR, MOLECULES; STARS, PRE-MAIN-SEQUENCE ID ABSORPTION FEATURES; INFRARED-SPECTRA; WATER; STARS; LINE; BAND; ICE AB We have searched for the strong C-O stretching absorption of solid methanol near 9.8-mu-m toward the heavily obscured protostars AFGL 961, AFGL 2591, the BN object and Mon R2 IRS 3. There is no clear evidence for this feature in the spectra, resulting in very conservative upper limits to the methanol abundance of 6% to 17% relative to solid H2O toward these objects. This is well below previous estimates of 50%-80% obtained toward W33 A, NGC 7538 IRS 9, AFGL 2136, and W3 IRS 5, which were based on the assignment of the interstellar 6.85-mu-m absorption feature to the methanol C-H bending mode. This study shows that such high methanol abundances are not a characteristic of all interstellar ices. RP SCHUTTE, WA (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 27 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1991 VL 382 IS 2 BP 523 EP 529 DI 10.1086/170739 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR012 UT WOS:A1991GR01200014 PM 11540082 ER PT J AU TOMLEY, L CASSEN, P STEIMANCAMERON, T AF TOMLEY, L CASSEN, P STEIMANCAMERON, T TI ON THE EVOLUTION OF GRAVITATIONALLY UNSTABLE PROTOSTELLAR DISKS SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, CIRCUMSTELLAR SHELLS; STARS, FORMATION ID T-TAURI STARS; ACCRETION DISK; GALAXIES; INSTABILITIES; STABILITY; COLLAPSE; MODELS; CLOUDS; CORES AB The formation of single stars from rotating interstellar clouds generally requires that the angular momentum of the cloud be redistributed in such a way that a major fraction of the mass (eventually residing in the star) retains only a minor fraction of the angular momentum, most of the latter being deposited in a circumstellar disk. Gravitational instabilities in a growing disk would promote such a redistribution by the action of self-excited density waves. We have attempted to quantify this process by conducting two-dimensional, N-body simulations of the nonlinear development of long-wavelength instabilities predicted to occur early in the formation stage of the disk, under conditions of controlled energy loss. Initial conditions are chosen to correspond to a specific solution of the rotating collapse problem, at a time when the disk and star masses are comparable. The results are quantified in terms of an empirical relationship between the local thermodynamic state of the disk, as characterized by Toomre's stability parameter Q and the imposed cooling rate, measured in terms of the local orbital frequency. It is suggested that the derived relationship has general applicability, although further calculations are required to test the degree to which this is true. Dynamical evolution rates are derived from the magnitude of the instability-generated torques and are shown to be linearly proportional to the cooling rates. In particular, it is confirmed that uncooled disks heat to the point of stability and cease to produce density waves, as found in previous studies. Gravitationally unstable cooled disks also heat up, but to an extent limited by the degree of cooling, and so their approach to stability is correspondingly limited; they evolve through the continued action of density waves. Thus it is demonstrated that the rate of evolution of gravitationally unstable disks is controlled by the rate at which thermal energy can escape the disk, just as in the case of convectively unstable disks and Hayashi track stars. 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 40 TC 70 Z9 70 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 DEC 1 PY 1991 VL 382 IS 2 BP 530 EP 543 DI 10.1086/170740 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR012 UT WOS:A1991GR01200015 ER PT J AU LADD, EF ADAMS, FC CASEY, S DAVIDSON, JA FULLER, GA HARPER, DA MYERS, PC PADMAN, R AF LADD, EF ADAMS, FC CASEY, S DAVIDSON, JA FULLER, GA HARPER, DA MYERS, PC PADMAN, R TI FAR-INFRARED AND SUBMILLIMETER WAVELENGTH OBSERVATIONS OF STAR-FORMING DENSE CORES .2. IMAGES SO ASTROPHYSICAL JOURNAL LA English DT Article DE SPECTROPHOTOMETRY; STARS, CIRCUMSTELLAR SHELLS; STARS, PRE-MAIN-SEQUENCE ID MOLECULAR CLOUD CORES; DARK CLOUDS; CONTINUUM OBSERVATIONS; PROTOSTARS; MASSES; OPTICS; DISK; DUST AB This paper reports on far-infrared and submillimeter wavelength observations of low-mass protostellar candidates. The data set comprises emission maps of nine sources observed over a wavelength range 100-800-mu-m. The emission is extended at all wavelengths longer than 100-mu-m. The apparent size of the emission regions is weakly correlated with the beam size and is consistent with an underlying specific intensity profile which is scale-free (i.e., I-nu decreases as a power law with distance). The observed emission maps are not circular, but have a mean aspect ratio of 1.3, and the position angles are similar to those determined from maps of molecular emission. The observational results are used in conjunction with theoretical considerations to constrain the physical properties of the putative protostellar envelopes. The best constrained parameter is the sum p + q of the power-law indices of the density and temperature distributions; this sum is shown to lie in the range 1.8 less-than-or-equal-to p + q less-than-or-equal-to 2.3 for the sources L1489 and L1527. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. YERKES OBSERV,WILLIAMS BAY,WI 53191. UNIV CAMBRIDGE,CAVENDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND. RP LADD, EF (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,MS-42,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 35 TC 62 Z9 62 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 1991 VL 382 IS 2 BP 555 EP 569 DI 10.1086/170742 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR012 UT WOS:A1991GR01200017 ER PT J AU BALASUBRAMANIAM, KS WEST, EA AF BALASUBRAMANIAM, KS WEST, EA TI VECTOR MAGNETIC-FIELDS IN SUNSPOTS .1. STOKES PROFILE ANALYSIS USING THE MARSHALL-SPACE-FLIGHT-CENTER MAGNETOGRAPH SO ASTROPHYSICAL JOURNAL LA English DT Article DE LINE PROFILES; POLARIZATION; SUN, MAGNETIC FIELDS; SUN, SUNSPOTS; ZEEMAN EFFECT AB The Marshall Space Flight Center (MSFC) vector magnetograph is a tunable filter magnetograph with a bandpass of 125 m-angstrom. We present results of the inversion of Stokes polarization profiles observed with the MSFC vector magnetograph centered on a sunspot to recover the vector magnetic field parameters and thermodynamic parameters of the spectral line forming region using the Fe I lambda-5250.2 spectral line using a nonlinear least-squares fitting technique. As a preliminary investigation, we also show that the recovered thermodynamic parameters could be better understood if we break down the fitted parameters like Doppler width, opacity ratio, and damping constant into more basic quantities like temperature, microturbulent velocity, or density parameter. RP BALASUBRAMANIAM, KS (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,CODE ES 52,HUNTSVILLE,AL 35812, USA. OI Balasubramaniam, Krishnan/0000-0003-2221-0933 NR 19 TC 15 Z9 15 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 DEC 1 PY 1991 VL 382 IS 2 BP 699 EP & DI 10.1086/170757 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR012 UT WOS:A1991GR01200032 ER PT J AU FERGUSON, HC DAVIDSEN, AF KRISS, GA BLAIR, WP BOWERS, CW DIXON, WV DURRANCE, ST FELDMAN, PD HENRY, RC KRUK, JW MOOS, HW VANCURA, O LONG, KS KIMBLE, RA AF FERGUSON, HC DAVIDSEN, AF KRISS, GA BLAIR, WP BOWERS, CW DIXON, WV DURRANCE, ST FELDMAN, PD HENRY, RC KRUK, JW MOOS, HW VANCURA, O LONG, KS KIMBLE, RA TI CONSTRAINTS ON THE ORIGIN OF THE ULTRAVIOLET UPTURN IN ELLIPTIC GALAXIES FROM HOPKINS ULTRAVIOLET TELESCOPE OBSERVATIONS OF NGC-1399 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC-1399); GALAXIES, STELLAR CONTENT; ULTRAVIOLET, SPECTRA ID STELLAR POPULATION; ENERGY-DISTRIBUTIONS; SURFACE PHOTOMETRY; IUE OBSERVATIONS; CENTRAL BULGE; SPECTRA; MODEL; STARS; EVOLUTION; CATALOG AB The giant elliptical galaxy NGC 1399 was observed with the Hopkins Ultraviolet Telescope (HUT) aboard the Astro-1 space shuttle mission in 1990 December. These are the first data to provide measurements of the spectral energy distribution of an elliptical galaxy shortward of Ly-alpha and to allow detection of absorption features in the sub 2000 angstrom UV. The spectrum shows no emission features other than well-known geocoronal lines. Strong Lyman series absorption is evident at the galaxy redshift. Other absorption features attributable to the hot stellar population are detected, but there is no evidence of C IV lambda-lambda-1548, 1551 absorption. We use these data to set constraints on the origin of the UV upturn in elliptical galaxies. The lack of detectable C IV absorption and the shape of the continuum spectrum exclude star formation with a standard IMF as the sole contributor to the 1550 angstrom flux. The spectral energy distributions predicted by the "hot-E" model of Guiderdoni and Rocca-Volmerange and the Bruzual mu-models do not match the observed spectrum. Postasymptotic giant branch (PAGB) stars can account for the spectrum near 1550 angstrom, because many have low carbon abundance in their envelopes. However, synthetic spectra produced from theoretical evolutionary tracks and stellar model atmospheres fail to fit to the observed spectral-energy distribution. If PAGB stars produce the UV upturn, then either they do not evolve along the standard tracks, or the (solar metallicity) model atmospheres used to construct the synthetic spectrum are inappropriate. The observed continuum flux decreases from 1050 angstrom to the Lyman limit, indicating that the light is dominated by stars with temperatures less than 25,000 K. For star-formation models, this temperature puts the main-sequence turnoff near B0, implying either that star formation ended approximately 2 x 10(7) yr ago, or that stars are currently forming with a truncated IMF. The continuum shape and presence of Lyman-series absorption suggest extreme horizontal-branch star models deserve additional attention. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP FERGUSON, HC (reprint author), JOHNS HOPKINS UNIV,HENRY A ROWLAND DEPT PHYS & ASTRON,CTR ASTROPHYS SCI,BALTIMORE,MD 21218, USA. RI Kimble, Randy/D-5317-2012; Kruk, Jeffrey/G-4047-2012 NR 45 TC 73 Z9 73 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 DEC 1 PY 1991 VL 382 IS 2 BP L69 EP L73 DI 10.1086/186215 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR014 UT WOS:A1991GR01400004 ER PT J AU MOOS, HW FELDMAN, PD DURRANCE, ST BLAIR, WP BOWERS, CW DAVIDSEN, AF DIXON, WV FERGUSON, HC HENRY, RC KIMBLE, RA KRISS, GA KRUK, JW LONG, KS VANCURA, O AF MOOS, HW FELDMAN, PD DURRANCE, ST BLAIR, WP BOWERS, CW DAVIDSEN, AF DIXON, WV FERGUSON, HC HENRY, RC KIMBLE, RA KRISS, GA KRUK, JW LONG, KS VANCURA, O TI DETERMINATION OF IONIC ABUNDANCES IN THE IO-TORUS USING THE HOPKINS ULTRAVIOLET TELESCOPE SO ASTROPHYSICAL JOURNAL LA English DT Article DE PLANETS, CHARGED PARTICLES; PLANETS, MAGNETOSPHERES; PLANETS, SATELLITES; ULTRAVIOLET, SPECTRA ID PLASMA TORUS; O-III; COLLISION STRENGTHS; OSCILLATOR-STRENGTHS; S-III; SPECTRUM; SULFUR; TRANSITION; RATIOS AB During the Astro-1 mission in 1990 December, the Hopkins Ultraviolet Telescope was used to obtain a 415-1864 angstrom spectrum of the emissions from the Io torus with approximately 3 angstrom resolution in first order (830-1864 angstrom). The approximately 1274 s observation of the east ansa took place during orbital night when spectral contamination by terrestrial airglow was minimal. A list of the 31 strongest features shows that, apart from five features that are totally or partially terrestrial, all are due to O+, S+, S++ and S+++. There is no evidence for elements other than oxygen and sulfur. However, the spectrum shows many additional weaker emission features so that the existence of minor species cannot be ruled out at this time. Because the HUT spectrum contains well resolved lines for all four of the major species, the mixing ratio (N(i)/n(e)) for each ion can be determined without using models of the spectral emissions, as is required for analysis of the Voyager UVS data, or a detailed geometric model of the torus plasma, as is required for IUE data. The relative concentration of O+ determined from the HUT observation is 38% less than that obtained from the Voyager UVS data. O III] lambda-lambda-1661, 1666 was detected at the 2 sigma-level. C1 CAMBRIDGE UNIV OBSERV,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP MOOS, HW (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,CTR ASTROPHYS SCI,BALTIMORE,MD 21218, USA. RI Kimble, Randy/D-5317-2012; Kruk, Jeffrey/G-4047-2012 NR 27 TC 49 Z9 49 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 DEC 1 PY 1991 VL 382 IS 2 BP L105 EP L108 DI 10.1086/186223 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR014 UT WOS:A1991GR01400012 ER PT J AU LEISAWITZ, D AF LEISAWITZ, D TI A MODEL FOR THE INFRARED-EMISSION FROM AN OB STAR CLUSTER ENVIRONMENT SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE CLUSTERS, OPEN; INFRARED, GENERAL; INTERSTELLAR, GRAINS; NEBULAE, H-II REGIONS; RADIATIVE TRANSFER; STARS, EARLY-TYPE ID H-II REGIONS; GIANT MOLECULAR CLOUDS; TEMPERATURE-FLUCTUATIONS; INTERSTELLAR GRAINS; LINE OBSERVATIONS; CO SURVEY; DUST; GALAXY; SUBMILLIMETER; RADIATION AB A model for the infrared emission from the neighborhood of an OB star cluster is described. The distribution of gas and dust around the stars, properties of the dust, and the cluster and interstellar radiation fields are variable. The model can be applied to regions around clusters embedded to various degrees in their parental molecular clouds (i.e., compact H II regions, blister-type H II regions, and the tenuous H II regions ionized by naked O stars). The model is used to simulate IRAS observations of a typical blister H II region. Infrared surface brightness and spectral energy distributions are predicted and the impact of limited spatial resolution is illustrated. The model results are shown to be consistent with observations of the exemplary outer Galaxy OB cluster NGC 7380. We plan to use the model as a diagnostic tool to probe the physical conditions and dust properties in star-formation regions and, ultimately, in an interpretation of the spectral energy distributions of spiral galaxies. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. NR 72 TC 7 Z9 7 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 DEC PY 1991 VL 77 IS 4 BP 451 EP 471 DI 10.1086/191613 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT978 UT WOS:A1991GT97800001 ER PT J AU PEPPER, LJ AF PEPPER, LJ TI NASA LONG-TERM STUDY OF ASTRONAUT HEALTH SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Editorial Material RP PEPPER, LJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 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 DEC PY 1991 VL 62 IS 12 BP 1210 EP 1210 PG 1 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA GR868 UT WOS:A1991GR86800017 ER PT J AU SALTZ, J BERRYMAN, H WU, J AF SALTZ, J BERRYMAN, H WU, J TI MULTIPROCESSORS AND RUN-TIME COMPILATION SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article; Proceedings Paper CT CONF ON PARALLEL COMPUTING : ACHIEVEMENTS, PROBLEMS AND PROSPECTS CY JUN 03-07, 1990 CL CAPRI, ITALY ID FACTORIZATION; SYSTEMS AB Run-time preprocessing plays a major role in many efficient algorithms in computer science, as well as playing an important role in exploiting multiprocessor architectures. We give examples that elucidate the importance of run-time preprocessing and show how these optimizations can be integrated into compilers. To support our arguments, we describe transformations implemented in prototype multiprocessor compilers and present benchmarks from the iPSC2/860, the CM-2 and the Encore Multimax/320. C1 NASA LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23065. NR 38 TC 26 Z9 26 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD DEC PY 1991 VL 3 IS 6 BP 573 EP 592 DI 10.1002/cpe.4330030607 PG 20 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA GY911 UT WOS:A1991GY91100006 ER PT J AU MAYHEW, MA WASILEWSKI, PJ JOHNSON, BD AF MAYHEW, MA WASILEWSKI, PJ JOHNSON, BD TI CRUSTAL MAGNETIZATION AND TEMPERATURE AT DEPTH BENEATH THE YILGARN BLOCK, WESTERN-AUSTRALIA INFERRED FROM MAGSAT DATA SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article ID CONTINENTAL-CRUST; BERGEN ARCS; UNITED-STATES; SHEAR ZONES; MODEL; ANOMALIES; BOUNDARY; NORWAY; ECLOGITIZATION; GRANULITES AB Variations in crustal magnetization along a seismic section across the Archean Yilgarn block of Western Australia inferred from Magsat data are interpreted as a subtle thermal effect arising from variations in depth to the Curie isotherm. The isotherm lies deep within the mantle of the eastern part of the province, but transects the crust-mantle transition and rises well into the crust on the western side. The model is consistent with heat flow variations along the section line. The mean crustal magnetization implied by the model is approximately 2 A/m. The temperature variation implied by the model is consistent with the hypothesis that the crust-mantle transition seen seismically corresponds to the mafic granulite-eclogite phase transition within a zone of igneous crustal underplating. C1 MACQUARIE UNIV,N RYDE,NSW 2113,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP MAYHEW, MA (reprint author), NATL SCI FDN,WASHINGTON,DC 20550, USA. NR 31 TC 14 Z9 14 U1 0 U2 1 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 DEC PY 1991 VL 107 IS 3-4 BP 515 EP 522 DI 10.1016/0012-821X(91)90097-2 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GZ589 UT WOS:A1991GZ58900007 ER PT J AU ROUGHGARDEN, J RUNNING, SW MATSON, PA AF ROUGHGARDEN, J RUNNING, SW MATSON, PA TI WHAT DOES REMOTE-SENSING DO FOR ECOLOGY SO ECOLOGY LA English DT Article ID TEMPERATE CONIFEROUS FORESTS; LEAF-AREA INDEX; SATELLITE DATA; VEGETATION INDEX; AVHRR DATA; EVAPOTRANSPIRATION; PHOTOSYNTHESIS; DEFORESTATION; EXCHANGE; CO2 C1 UNIV MONTANA,DEPT FORESTRY,MISSOULA,MT 59812. NASA,AMES RES CTR,ECOSYST SCI & TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP ROUGHGARDEN, J (reprint author), STANFORD UNIV,DEPT BIOL SCI,STANFORD,CA 94305, USA. NR 40 TC 120 Z9 130 U1 1 U2 18 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD DEC PY 1991 VL 72 IS 6 BP 1918 EP 1922 DI 10.2307/1941546 PG 5 WC Ecology SC Environmental Sciences & Ecology GA GV769 UT WOS:A1991GV76900002 ER PT J AU WICKLAND, DE AF WICKLAND, DE TI MISSION TO PLANET EARTH - THE ECOLOGICAL PERSPECTIVE SO ECOLOGY LA English DT Article ID CANOPY; SPACE; EVAPOTRANSPIRATION; REFLECTANCE; VEGETATION RP WICKLAND, DE (reprint author), NASA,DIV EARTH SCI & APPLICAT,WASHINGTON,DC 20546, USA. NR 31 TC 28 Z9 28 U1 0 U2 1 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD DEC PY 1991 VL 72 IS 6 BP 1923 EP 1933 DI 10.2307/1941547 PG 11 WC Ecology SC Environmental Sciences & Ecology GA GV769 UT WOS:A1991GV76900003 ER PT J AU USTIN, SL WESSMAN, CA CURTISS, B KASISCHKE, E WAY, J VANDERBILT, VC AF USTIN, SL WESSMAN, CA CURTISS, B KASISCHKE, E WAY, J VANDERBILT, VC TI OPPORTUNITIES FOR USING THE EOS IMAGING SPECTROMETERS AND SYNTHETIC APERTURE RADAR IN ECOLOGICAL MODELS SO ECOLOGY LA English DT Article ID LEAF WATER-CONTENT; HIGH-RESOLUTION RADIOMETER; CONIFER FOREST CANOPY; SPECTRAL REFLECTANCE; VEGETATION; PHOTOSYNTHESIS; EVAPOTRANSPIRATION; TRANSPIRATION; BACKSCATTER; ABUNDANCE C1 UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,CSES,BOULDER,CO 80309. ENVIRONM RES INST MICHIGAN,RADAR SCI LAB,ANN ARBOR,MI 48107. CALTECH,JET PROP LAB,PASADENA,CA 91109. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP USTIN, SL (reprint author), UNIV CALIF DAVIS,DEPT LAND AIR & WATER RESOURCES,DAVIS,CA 95616, USA. NR 63 TC 61 Z9 62 U1 0 U2 2 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD DEC PY 1991 VL 72 IS 6 BP 1934 EP 1945 PG 12 WC Ecology SC Environmental Sciences & Ecology GA GV769 UT WOS:A1991GV76900004 ER PT J AU HO, H TSAI, MY MORTON, J FARLEY, GL AF HO, H TSAI, MY MORTON, J FARLEY, GL TI AN EXPERIMENTAL INVESTIGATION OF IOSIPESCU SPECIMEN FOR COMPOSITE-MATERIALS SO EXPERIMENTAL MECHANICS LA English DT Article ID SHEAR TEST AB A detailed experimental evaluation of the losipescu specimen tested in the modified Wyoming fixture is presented. Moire interferometry is employed to determine the deformation of unidirectional and cross-ply graphite-epoxy specimens. The results of the moire experiments are compared to those from the traditional strain-gage method. It is shown that the strain-gage readings from one surface of a specimen together with corresponding data from moire interferometry on the opposite face documented an extreme sensitivity of some fiber orientations to twisting. A localized hybrid analysis is introduced to perform efficient reduction of moire data, producing whole-field strain distributions in the specimen test sections. C1 USA,AEROSTRUCT DIRECTORATE,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 18 TC 26 Z9 26 U1 0 U2 1 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD DEC PY 1991 VL 31 IS 4 BP 328 EP 336 DI 10.1007/BF02325989 PG 9 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA GY819 UT WOS:A1991GY81900006 ER PT J AU GARRETT, ES HUDAKROOS, M AF GARRETT, ES HUDAKROOS, M TI DEVELOPING AN HACCP-BASED INSPECTION SYSTEM FOR THE SEAFOOD INDUSTRY SO FOOD TECHNOLOGY LA English DT Article RP GARRETT, ES (reprint author), NATL MARINE FISHERIES SERV,NATL SEAFOOD INSPECT LAB,PO DRAWER 1207,PASCAGOULA,MS 39568, USA. NR 14 TC 5 Z9 5 U1 1 U2 1 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA SUITE 300 221 N LASALLE ST, CHICAGO, IL 60601-1291 SN 0015-6639 J9 FOOD TECHNOL-CHICAGO JI Food Technol. PD DEC PY 1991 VL 45 IS 12 BP 53 EP 57 PG 5 WC Food Science & Technology SC Food Science & Technology GA GX358 UT WOS:A1991GX35800003 ER PT J AU SHEPARD, MK ARVIDSON, RE GUINNESS, EA AF SHEPARD, MK ARVIDSON, RE GUINNESS, EA TI SCATTERING BEHAVIOR OF LUNAR LAKE PLAYA DETERMINED FROM PARABOLA BIDIRECTIONAL REFLECTANCE DATA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SPECTROSCOPY AB Bidirectional reflectance data obtained with the PARABOLA instrument at Lunar Lake, Nevada, were analyzed to determine the scattering properties of playas. The data are approximated by a Lambertian function, except at high phase angles in the solar principal plane, where Fresnel reflectance appears to dominate. The data also depart slightly (15%) from a Lambertian function at high emission angles in all azimuthal planes. No published photometric model accounts for the observed data. It is hypothesized that the observed scattering behavior is the superposition of volume and surface (Fresnel) scattering mechanisms. C1 WASHINGTON UNIV,DEPT EARTH & PLANETARY SCI,ST LOUIS,MO 63130. NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. RP SHEPARD, MK (reprint author), WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130, USA. NR 14 TC 7 Z9 7 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 DEC PY 1991 VL 18 IS 12 BP 2241 EP 2244 DI 10.1029/91GL02899 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300017 ER PT J AU LARY, DJ PYLE, JA WEBSTER, CR MAY, RD AF LARY, DJ PYLE, JA WEBSTER, CR MAY, RD TI THE BLISS MEASUREMENTS OF NO2 - SOME NEW INSIGHTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DIODE-LASER SPECTROMETER; RADIATION-FIELD; STRATOSPHERE; TROPOSPHERE; HNO3 AB The diurnal variation of NO2 measured near 30 km by the BLISS in-situ laser spectrometer is compared with calculations from a photochemical model that includes a detailed description of multiple scattering. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP LARY, DJ (reprint author), UNIV CAMBRIDGE,DEPT CHEM,LENSFIELD RD,CAMBRIDGE CB2 1EW,ENGLAND. RI Lary, David/A-6163-2010 NR 8 TC 5 Z9 5 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD DEC PY 1991 VL 18 IS 12 BP 2261 EP 2263 DI 10.1029/91GL02732 PG 3 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300022 ER PT J AU KING, JC BRUNE, WH TOOHEY, DW RODRIGUEZ, JM STARR, WL VEDDER, JF AF KING, JC BRUNE, WH TOOHEY, DW RODRIGUEZ, JM STARR, WL VEDDER, JF TI MEASUREMENTS OF CLO AND O3 FROM 21-DEGREES-N TO 61-DEGREES-N IN THE LOWER STRATOSPHERE DURING FEBRUARY 1988 - IMPLICATIONS FOR HETEROGENEOUS CHEMISTRY SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE; LATITUDE; AEROSOLS; N2O5 AB The decline in stratospheric ozone at northern midlatitudes in wintertime may be caused by chlorine photochemistry that has been enhanced by heterogeneous reactions. We examine the possibility that the heterogeneous reaction of N2O5 on sulfate aerosols is the cause of this decadal ozone decline by comparing ClO and O3 measurements made in the lower stratosphere during February, 1988, with results from a two-dimensional model. At midlatitudes, the abundances, latitudinal, and seasonal gradients of the observed ClO are similar to the results of a model with heterogeneous chemistry, but are in strong disagreement with the results from the model with only gas-phase chemistry. At low latitudes, agreement is best with the results of the model with only gas-phase chemistry. These limited observations indicate that the amount of reactive chlorine is being enhanced, and that heterogeneous chemistry is a likely cause, but the details of the heterogeneous chemistry and the possibility of other mechanisms still need to be considered. C1 ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139. SAN JOSE STATE UNIV FDN,SAN JOSE,CA 94056. HARVARD UNIV,DEPT EARTH & PLANETARY SCI,CAMBRIDGE,MA 02138. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP KING, JC (reprint author), PENN STATE UNIV,DEPT METEOROL,UNIV PK,PA 16802, USA. RI Toohey, Darin/A-4267-2008; Rodriguez, Jose/G-3751-2013 OI Toohey, Darin/0000-0003-2853-1068; Rodriguez, Jose/0000-0002-1902-4649 NR 18 TC 21 Z9 21 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 DEC PY 1991 VL 18 IS 12 BP 2273 EP 2276 DI 10.1029/91GL02628 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300025 ER PT J AU CHANDRA, S STOLARSKI, RS AF CHANDRA, S STOLARSKI, RS TI RECENT TRENDS IN STRATOSPHERIC TOTAL OZONE - IMPLICATIONS OF DYNAMIC AND EL-CHICHON PERTURBATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ERUPTION; DEPLETION; MINIMUM AB The recently reprocessed Nimbus-7 TOMS total ozone data from 1979 to 1989 are analyzed to assess the global impact of the El Chichon volcanic eruption on stratospheric total ozone. An apparent decrease in total ozone of 5 to 6% is present during the winter of 1982-83 following the eruption of El Chichon. A regression analysis of total ozone with the equatorial zonal wind at 30 mb indicates that response to the quasi-biennial oscillation can explain much of the observed ozone anomaly, and that the total ozone decrease which can be attributed to El Chichon is at most 2 to 4 percent. This study also suggests that the interannual variability caused by the quasi-biennial oscillation and planetary wave activity may introduce apparent seasonal trends in total ozone and temperature in the lower stratosphere, particularly if the length of the data record is not very long. Such trends may affect the assessment of total ozone changes caused by chemical perturbations. RP CHANDRA, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Stolarski, Richard/B-8499-2013 OI Stolarski, Richard/0000-0001-8722-4012 NR 21 TC 53 Z9 53 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD DEC PY 1991 VL 18 IS 12 BP 2277 EP 2280 DI 10.1029/91GL02779 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300026 ER PT J AU GREENSTADT, EW CORONITI, FV MOSES, SL TSURUTANI, BT OMIDI, N QUEST, KB KRAUSSVARBAN, D AF GREENSTADT, EW CORONITI, FV MOSES, SL TSURUTANI, BT OMIDI, N QUEST, KB KRAUSSVARBAN, D TI WEAK, QUASIPARALLEL PROFILES OF EARTHS BOW SHOCK - A COMPARISON BETWEEN NUMERICAL SIMULATIONS AND ISEE-3 OBSERVATIONS ON THE FAR FLANK SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID QUASI-PARALLEL SHOCKS; INTERPLANETARY SHOCKS; COLLISIONLESS SHOCKS; MAGNETIC-FIELD; MACH NUMBER; WAVES; UPSTREAM AB Over 200 crossings of the distant downwind flanks of Earth's magnetosonic bow shock by ISEE 3 included many cases of weak, or low Mach number, quasiparallel shocks. A consistent feature of the magnetic field profiles was the presence of large amplitude, near periodic to irregular transverse oscillations downstream from even the weakest Q parallel-to shocks. Large downstream perturbations with whistler-like features similar to those of the observations appear in one-dimensional simulations when M(A) > 2.5 but not when M(A) = 2.1. The observed cases with downstream waves also occurred when M(A) > almost-equal-to 2.5, suggesting the importance of the Alfven as opposed to magnetosonic Mach number in determining the signature of weak, Q parallel-to shocks. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF SAN DIEGO,DEPT ELECT & COMP ENGN,LA JOLLA,CA 92093. RP GREENSTADT, EW (reprint author), TRW CO INC,R1-1170,1 SPACE PK,REDONDO BEACH,CA 90278, USA. NR 15 TC 10 Z9 10 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 DEC PY 1991 VL 18 IS 12 BP 2301 EP 2304 DI 10.1029/91GL02246 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300032 ER PT J AU SZEGO, K SHAPIRO, VS SHEVCHENKO, VI SAGDEEV, RZ KASPRZAK, WT NAGY, AF AF SZEGO, K SHAPIRO, VS SHEVCHENKO, VI SAGDEEV, RZ KASPRZAK, WT NAGY, AF TI PHYSICAL PROCESSES IN THE PLASMA MANTLE OF VENUS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ENERGETIC IONS; IONOPAUSE; ORBITER; MARS AB The Phobos-2 observations established the presence of a turbulent region on the dayside, called the mantle, just outside the magnetic barrier at Mars. This mantle is the interaction region of cold Martian ions and the shocked solar wind. This work presents the results of a study, which analyzed data from ten Pioneer Venus orbits, in order to see whether similar wave particle interaction processes also exist in the corresponding region around Venus. The first conclusion is that the apparent physical processes in the mantle are indeed similar around Venus and Mars. The planetary thermal O+ ions outside the ionopause interact with the shocked solar wind and excite electrostatic waves close to the lower hybrid frequency. These wave propagate inwards, heating first the electron and deeper down in the ionosphere the thermal ion population. The observed superthermal ions are believed to be the product of this wave particle interaction process. Our second conclusion is that the wave energy transferred to the thermal electrons is of the right magnitude (approximately 4 x 10(9) eV cm-2 s-1) to provide the supplemental heat source necessary to reconcile observed and calculated electron temperatures in the ionosphere. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. MOSCOW SPACE RES INST,MOSCOW,USSR. UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. RP SZEGO, K (reprint author), HUNGARIAN ACAD SCI,CENT RES INST PHYS,H-1525 BUDAPEST,HUNGARY. NR 18 TC 35 Z9 35 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD DEC PY 1991 VL 18 IS 12 BP 2305 EP 2308 DI 10.1029/91GL02086 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GY093 UT WOS:A1991GY09300033 ER PT J AU MARAIS, DJD AF MARAIS, DJD TI MICROBIAL MATS, STROMATOLITES AND THE RISE OF OXYGEN IN THE PRECAMBRIAN ATMOSPHERE SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT WORKSHOP ON ATMOSPHERIC OXYGEN VARIATION THROUGH GEOLOGIC TIME CY JUL 16-18, 1990 CL PENN STATE UNIV, EARTH SYST SCI CTR, STATE COLLEGE, PA SP PENN STATE UNIV HO PENN STATE UNIV, EARTH SYST SCI CTR ID WESTERN-AUSTRALIA; CARBON; PHOTOSYNTHESIS; OLD RP MARAIS, DJD (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 26 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD DEC PY 1991 VL 97 IS 1-2 BP 93 EP 96 PG 4 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA GZ960 UT WOS:A1991GZ96000009 ER PT J AU CRUIKSHANK, DP ALLAMANDOLA, LJ HARTMANN, WK THOLEN, DJ BROWN, RH MATTHEWS, CN BELL, JF AF CRUIKSHANK, DP ALLAMANDOLA, LJ HARTMANN, WK THOLEN, DJ BROWN, RH MATTHEWS, CN BELL, JF TI SOLID CN BEARING MATERIAL ON OUTER SOLAR-SYSTEM BODIES SO ICARUS LA English DT Article ID REFLECTANCE SPECTRA; COMETARY NUCLEI; CHEMISTRY; RINGS; COLOR; SPECTROPHOTOMETRY; COLORIMETRY; ATMOSPHERES; DISCHARGE; ASTEROIDS C1 PLANETARY SCI INST,TUCSON,AZ 85719. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV ILLINOIS,DEPT CHEM,CHICAGO,IL 60680. RP CRUIKSHANK, DP (reprint author), NASA,AMES RES CTR,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 61 TC 84 Z9 84 U1 0 U2 2 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 DEC PY 1991 VL 94 IS 2 BP 345 EP 353 DI 10.1016/0019-1035(91)90233-J PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW399 UT WOS:A1991GW39900009 PM 11538090 ER PT J AU PIERCE, DA AF PIERCE, DA TI THE MASS OF NEPTUNE SO ICARUS LA English DT Article ID ELEMENTS; NEREID C1 EL CAMINO COLL,TORRANCE,CA 90506. RP PIERCE, DA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 50 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1991 VL 94 IS 2 BP 413 EP 419 DI 10.1016/0019-1035(91)90238-O PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW399 UT WOS:A1991GW39900014 ER PT J AU MARLEY, MS AF MARLEY, MS TI NONRADIAL OSCILLATIONS OF SATURN SO ICARUS LA English DT Article ID JOVIAN SEISMOLOGY; GIANT PLANETS; HIGH-PRESSURE; ZONAL FLOW; JUPITER; METEOROLOGY; ATMOSPHERES; CONVECTION; INTERIORS; MIXTURES RP MARLEY, MS (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. RI Marley, Mark/I-4704-2013; OI Marley, Mark/0000-0002-5251-2943 NR 46 TC 18 Z9 18 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 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1991 VL 94 IS 2 BP 420 EP 435 DI 10.1016/0019-1035(91)90239-P PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW399 UT WOS:A1991GW39900015 ER PT J AU SHOWALTER, MR CUZZI, JN LARSON, SM AF SHOWALTER, MR CUZZI, JN LARSON, SM TI STRUCTURE AND PARTICLE PROPERTIES OF SATURNS E-RING SO ICARUS LA English DT Article ID JUPITERS RING; OUTER RING; ENCELADUS; PHOTOMETRY; SATELLITES; DUST; SCATTERING; DISCOVERY; SYSTEM; PLASMA C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP SHOWALTER, MR (reprint author), STANFORD UNIV,CTR RADAR ASTRON,223 DURAND BLDG,STANFORD,CA 94305, USA. NR 56 TC 124 Z9 124 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 0019-1035 J9 ICARUS JI Icarus PD DEC PY 1991 VL 94 IS 2 BP 451 EP 473 DI 10.1016/0019-1035(91)90241-K PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GW399 UT WOS:A1991GW39900017 ER PT J AU ROSSI, DV SONG, JI FOSSUM, ER KIRCHNER, PD PETTIT, GD WOODALL, JM AF ROSSI, DV SONG, JI FOSSUM, ER KIRCHNER, PD PETTIT, GD WOODALL, JM TI A RESISTIVE-GATE IN0.53GA0.47AS/INP HETEROSTRUCTURE CCD SO IEEE ELECTRON DEVICE LETTERS LA English DT Article ID MICROWAVE PERFORMANCE AB The first InGaAs/InP charge-coupled device (CCD) is demonstrated, exhibiting a charge transfer efficiency (CTE) of 0.98 at 13 MHz and 1 GHz. Cooling the device improves the charge transfer efficiency to greater than 0.99 at 13-MHz clock frequency. The 0.76-eV In0.53Ga0.47As bandgap makes this structure applicable to direct detection short-wavelength infrared (SWIR) imagers. C1 BELL COMMUN RES INC,RED BANK,NJ 07701. CALTECH,JET PROP LAB,PASADENA,CA 91109. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP ROSSI, DV (reprint author), COLUMBIA UNIV,DEPT ELECT ENGN,NEW YORK,NY 10027, USA. NR 9 TC 1 Z9 1 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 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD DEC PY 1991 VL 12 IS 12 BP 688 EP 690 DI 10.1109/55.116956 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA GR706 UT WOS:A1991GR70600015 ER PT J AU Chorey, CM Miranda, FA Bhasin, KB AF Chorey, C. M. Miranda, F. A. Bhasin, K. B. TI Coaxial Line Configuration for Microwave Power Transmission Study of YBa2Cu3O7-delta Thin Films SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article AB Microwave transmission measurements through YBa2Cu3O7-delta (YBCO) high transition temperature superconducting (HTS) thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer shaped discs, polished, and coated with laser ablated YBCO. These samples were mounted in the 50-Omega coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films. C1 [Chorey, C. M.] Sverdrup Technol, LeRC Grp, Cleveland, OH 44135 USA. [Miranda, F. A.; Bhasin, K. B.] NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chorey, CM (reprint author), Sverdrup Technol, LeRC Grp, Cleveland, OH 44135 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1051-8223 EI 1558-2515 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD DEC PY 1991 VL 1 IS 4 BP 178 EP 180 DI 10.1109/77.107404 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA V30NY UT WOS:000208823900007 ER PT J AU NIEBUR, E NIEBUR, D AF NIEBUR, E NIEBUR, D TI NUMERICAL IMPLEMENTATION OF SEALED-END BOUNDARY-CONDITIONS IN CABLE THEORY SO IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING LA English DT Note ID EXTRACELLULAR POTENTIALS; SIMULATION AB We show that a frequently used numerical implementation of von Neumann boundary conditions (zero inflowing current) in cable theory is incorrect. Correct implementations are given and it is shown that they yield results in good agreement with known analytical solutions. C1 CALTECH,COMP & NEURAL SYST 216-76,PASADENA,CA 91109. SWISS FED INST TECHNOL,DEPT ELECT ENGN,CH-1015 LAUSANNE,SWITZERLAND. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP NIEBUR, E (reprint author), UNIV LAUSANNE,INST THEORET PHYS,CH-1015 LAUSANNE,SWITZERLAND. NR 18 TC 6 Z9 7 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 0018-9294 J9 IEEE T BIO-MED ENG JI IEEE Trans. Biomed. Eng. PD DEC PY 1991 VL 38 IS 12 BP 1266 EP 1271 DI 10.1109/10.137293 PG 6 WC Engineering, Biomedical SC Engineering GA GT086 UT WOS:A1991GT08600012 PM 1774089 ER PT J AU LIN, TL DEJEWSKI, SM KSENDZOV, A JONES, EW AF LIN, TL DEJEWSKI, SM KSENDZOV, A JONES, EW TI SIGE/SI CAMEL-BARRIER HETEROJUNCTION INTERNAL PHOTOEMISSION LWIR DETECTOR SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Meeting Abstract C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 2 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 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD DEC PY 1991 VL 38 IS 12 BP 2696 EP 2696 DI 10.1109/16.158711 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA GP300 UT WOS:A1991GP30000033 ER PT J AU GREENHALL, CA AF GREENHALL, CA TI RECIPES FOR DEGREES OF FREEDOM OF FREQUENCY STABILITY ESTIMATORS SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB The Allan variance for an averaging time tau can be estimated either from all available phase samples or from a subgrid of samples with spacing tau. This paper gives a set of computational recipes that yield the variance of both estimators, with less than 2% error, for the five power-law components of the classical continuous-time clock noise model. RP GREENHALL, CA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 17 TC 47 Z9 48 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD DEC PY 1991 VL 40 IS 6 BP 994 EP 999 DI 10.1109/19.119780 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HF317 UT WOS:A1991HF31700021 ER PT J AU SWIFT, CT LEVINE, DM RUF, CS AF SWIFT, CT LEVINE, DM RUF, CS TI APERTURE SYNTHESIS CONCEPTS IN MICROWAVE REMOTE-SENSING OF THE EARTH SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article; Proceedings Paper CT INTERNATIONAL MICROWAVE SYMP CY JUN 10-14, 1991 CL BOSTON, MA SP IEEE, MICROWAVE THEORY & TECH SOC AB Aperture synthesis concepts have been used for many years in radio astronomy to achieve high image resolution at a reasonable cost. The time has come for earth remote sensing technology to consider some of these techniques to meet the cost challenges of large antennas in space for these and other applications. The electronically scanned thinned array radiometer is put forward as a viable alternative to improve spatial resolution by an order of magnitude over what is presently achieved by microwave imaging systems that are collecting data from earth orbit. C1 NASA,GODDARD SPACE FLIGHT CTR,MICROWAVE SENSORS BRANCH,GREENBELT,MD 20771. CALTECH,JET PROP LAB,MICROWAVE OBSERVAT SYST SECT,TECH STAFF,PASADENA,CA 91109. RP SWIFT, CT (reprint author), UNIV MASSACHUSETTS,DEPT ELECT & COMP ENGN,AMHERST,MA 01003, USA. RI Ruf, Christopher/I-9463-2012 NR 8 TC 25 Z9 32 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 DEC PY 1991 VL 39 IS 12 BP 1931 EP 1935 DI 10.1109/22.106530 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA GW458 UT WOS:A1991GW45800004 ER PT J AU WHITAKER, S CANARIS, J LIU, K AF WHITAKER, S CANARIS, J LIU, K TI SEU HARDENED MEMORY CELLS FOR A CCSDS REED SOLOMON ENCODER SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB ID INDUCED SOFT ERRORS; UPSETS; DESIGN; SRAM AB This paper1 reports a design technique to harden CMOS memory circuits against Single Event Upset (SEU) in the space environment. The design technique provides a recovery mechanism which is independent of the shape of the upsetting event. A RAM cell and Flip Flop design are presented to demonstrate the method. The Flip Flop was used in the control circuitry for a Reed Solomon encoder designed for the Space Station and Explorer platforms. RP WHITAKER, S (reprint author), UNIV IDAHO,NASA,SPACE ENGN RES CTR VLSI SYST DESIGN,MOSCOW,ID 83843, USA. NR 21 TC 45 Z9 49 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1471 EP 1477 DI 10.1109/23.124134 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300061 ER PT J AU BLAES, BR SOLI, GA BUEHLER, MG AF BLAES, BR SOLI, GA BUEHLER, MG TI BENCH-LEVEL CHARACTERIZATION OF A CMOS STANDARD-CELL D-LATCH USING ALPHA-PARTICLE SENSITIVE TEST CIRCUITS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB AB This paper describes a methodology for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-mu-m n-well CMOS 4k-bit test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09-mu-m was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 Mev cm2/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV cm2/mg was determined. RP BLAES, BR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1486 EP 1492 DI 10.1109/23.124136 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300063 ER PT J AU NICHOLS, DK SMITH, LS SCHWARTZ, HR SOLI, G WATSON, K KOGA, R CRAIN, WR CRAWFORD, KB HANSEL, SJ LAU, DD AF NICHOLS, DK SMITH, LS SCHWARTZ, HR SOLI, G WATSON, K KOGA, R CRAIN, WR CRAWFORD, KB HANSEL, SJ LAU, DD TI UPDATE ON PARTS SEE SUSCEPTIBILITY FROM HEAVY-IONS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB ID TRENDS AB Jet Propulsion Laboratory (JPL) and The Aerospace Corporation have collected a fourth set of heavy ion single event effects (SEE) test data since their last joint contributions to IEEE Transactions on Nuclear Science in December 1985, 1987, and 1989. Trends in SEE susceptibility (including soft errors and latchup) for state-of-the-art parts are displayed. C1 AEROSPACE CORP,SPACE SCI LAB,EL SEGUNDO,CA 90245. RP NICHOLS, DK (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 6 TC 8 Z9 8 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1529 EP 1539 DI 10.1109/23.124142 PN 1 PG 11 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300069 ER PT J AU LABEL, K STASSINOPOULOS, EG BRUCKER, GJ AF LABEL, K STASSINOPOULOS, EG BRUCKER, GJ TI TRANSIENT SEUS IN A FIBER OPTIC-SYSTEM FOR SPACE APPLICATIONS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB AB Light-weight and high capacity communication systems on board satellites, which are evolving rapidly in size and complexity, are becoming increasingly necessary for efficient electronic application in space. A fiber optics system can provide this capability. This paper presents the results of an investigation on the SEU sensitivity for a fiber optic operating system. Measurements were made on the upset cross sections for the system in static and dynamic modes of operation. The heavy ion SEU test facility at Brookhaven and the proton facility at Harvard University were used in this study. Cross sections were obtained for Honeywell transmitter and receiver devices operating in a system at a frequency of 100 kHz. Both devices were independently irradiated. The results show that the dynamic mode was the worst case, and the receiver was the most sensitive part type in the system. The threshold Linear Energy Transfer (LET) for the receiver was determined to be 1.6 MeV.cm2/mg for the three input signals used in the tests, which were: a continuous high state, a low state, and a 100 kH square wave. C1 GE,DIV ASTROSPACE,PRINCETON,NJ. RP LABEL, K (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 2 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1546 EP 1550 DI 10.1109/23.124144 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300071 ER PT J AU SHAW, DC LOWRY, L BARNES, C ZAKHARIA, M AGARWAL, S RAX, B AF SHAW, DC LOWRY, L BARNES, C ZAKHARIA, M AGARWAL, S RAX, B TI POST IRRADIATION EFFECTS (PIE) IN INTEGRATED-CIRCUITS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB ID DOSE HARDNESS ASSURANCE; POSTIRRADIATION RESPONSE; MECHANICAL-STRESS; MOS STRUCTURES; RADIATION; TRANSISTORS; DEVICES; DAMAGE AB Post Irradiation Effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si). RP SHAW, DC (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 25 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1584 EP 1589 DI 10.1109/23.124149 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300076 ER PT J AU FREDERICKSON, AR MULLEN, EG BRAUTIGAM, DH KERNS, KJ ROBINSON, PA HOLMAN, EG AF FREDERICKSON, AR MULLEN, EG BRAUTIGAM, DH KERNS, KJ ROBINSON, PA HOLMAN, EG TI RADIATION-INDUCED INSULATOR DISCHARGE PULSES IN THE CRRES INTERNAL DISCHARGE MONITOR SATELLITE EXPERIMENT SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB ID SURFACES AB The Internal Discharge Monitor (IDM) is designed to observe electrical pulses from common electrical insulators in space service. The IDM is flying on the Combined Release and Radiation Effects Satellite (CRRES). The sixteen insulator samples include G10 circuit boards, FR4 and PTFE fiberglass circuit boards, FEP Teflon, alumina, and wires with common insulations. The samples are fully enclosed, mutually isolated, and space radiation penetrates 0.02 cm of aluminum before striking the samples. The IDM results indicate the rate at which insulator pulses occur. Pulsing began on the seventh orbit. The maximum pulse rate occurred near orbit 600 when over 50 pulses occurred. The average pulse rate is approximately two per orbit, but nearly half of the first 600 orbits experienced no pulses. The pulse rate per unit flux of high energy electrons has not changed dramatically over the first ten months in space. These pulse rates are in agreement with laboratory experience on shorter time scales. Several of the samples have never pulsed. IDM pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on CRRES. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. BOSTON COLL,DEPT PHYS,CHESTNUT HILL,MA 02167. RP FREDERICKSON, AR (reprint author), PHILLIPS LAB,GEOPHYS DIRECTORATE,BEDFORD,MA 01731, USA. NR 16 TC 15 Z9 16 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1614 EP 1621 DI 10.1109/23.124153 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300080 ER PT J AU LIN, YS BUEHLER, MG RAY, KP SOKOLOSKI, MM AF LIN, YS BUEHLER, MG RAY, KP SOKOLOSKI, MM TI CRRES MICROELECTRONIC TEST CHIP SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 28TH INTERNATIONAL CONF ON NUCLEAR AND SPACE RADIATION EFFECTS CY JUL 15-19, 1991 CL SAN DIEGO, CA SP IEEE, DEFENSE NUCL AGCY, SANDIA NATL LABS, JET PROPULS LAB AB The JPL CRRES chip was designed and fabricated in 1985 and included in the CRRES MEP. MOSFET Matrix results show the effect of shielding on radiation-induced MOSFET threshold voltage shifts and channel mobility degradation. Shielded (middle board) MOSFETs have a threshold-voltage damage factor that is approximately three-orders of magnitude smaller than would be estimated from Co-60 ground tests. Unshielded (outer board) MOSFETs have a threshold-voltage damage factor that would be estimated from Co-60 ground tests. Temperature swings as large as 23-degrees-C with a 22.5 orbit periodicity affected the MOSFET data and was removed from the data in order to reveal the radiation effects. This experiment demonstrated the feasibility of characterizing MOSFETs in a matrix thus reducing the complexity and mass of the experiment. C1 PHILLIPS LAB,BEDFORD,MA 01731. NASA,OFF AERONAUT & EXPLORAT TECHNOL,WASHINGTON,DC 20546. RP LIN, YS (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 9 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 1991 VL 38 IS 6 BP 1678 EP 1685 DI 10.1109/23.124162 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GZ173 UT WOS:A1991GZ17300089 ER PT J AU WILBUR, PJ JAHN, RG CURRAN, FC AF WILBUR, PJ JAHN, RG CURRAN, FC TI SPACE ELECTRIC PROPULSION PLASMAS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Electric thrusters offer the promise of a substantial improvement in performance over that of conventional chemical rockets currently used in space propulsion applications. Thrust is produced in three separate classes of thrusters by: 1) expanding an electrically heated plasma in a nozzle, 2) accelerating a plasma through the application of an electromagnetic body force, or 3) accelerating ions in an electric field. Each of these means of producing thrust involves plasmas that are at once different, phenomenologically rich, and worthy of separate consideration. C1 PRINCETON UNIV,SCH ENGN & APPL SCI,PRINCETON,NJ 08544. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP WILBUR, PJ (reprint author), COLORADO STATE UNIV,DEPT MECH ENGN,ENGN RES CTR,FT COLLINS,CO 80523, USA. NR 40 TC 17 Z9 18 U1 2 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD DEC PY 1991 VL 19 IS 6 BP 1167 EP 1179 DI 10.1109/27.125039 PG 13 WC Physics, Fluids & Plasmas SC Physics GA HD295 UT WOS:A1991HD29500015 ER PT J AU ROSENFELD, M KWAK, D AF ROSENFELD, M KWAK, D TI TIME-DEPENDENT SOLUTIONS OF VISCOUS INCOMPRESSIBLE FLOWS IN MOVING COORDINATES SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE INCOMPRESSIBLE NAVIER STOKES; TIME-DEPENDENT; MOVING COORDINATE SYSTEMS; FINITE VOLUME; FRACTIONAL STEP ID CHANNEL; INDENTATION; CYLINDER; WAVES AB A time-accurate solution method for the incompressible Navier-Stokes equations in generalized moving coordinates is presented. A finite volume discretization method that satisfies the geometric conservation laws for time-varying computational cells is used. The discrete equations are solved by a fractional step solution procedure. The solution is second-order-accurate in space and first-order-accurate in time. The pressure and the volume fluxes are chosen as the unknowns to facilitate the formulation of a consistent Poisson equation and thus to obtain a robust Poisson solver with favourable convergence properties. The method is validated by comparing the solutions with other numerical and experimental results. Good agreement is obtained in all cases. C1 TEL AVIV UNIV,FAC ENGN,DEPT FLUID MECH,IL-69978 TEL AVIV,ISRAEL. RP ROSENFELD, M (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 18 TC 33 Z9 33 U1 1 U2 4 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 DEC PY 1991 VL 13 IS 10 BP 1311 EP 1328 DI 10.1002/fld.1650131008 PG 18 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA GY608 UT WOS:A1991GY60800007 ER PT J AU LUBECKE, VM MCGRATH, WR RUTLEDGE, DB AF LUBECKE, VM MCGRATH, WR RUTLEDGE, DB TI SLIDING BACKSHORTS FOR PLANAR CIRCUITS SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE PLANAR CIRCUITS; ADJUSTABLE TUNING ELEMENTS; SUBMILLIMETER; SIS ID SIS RECEIVER; JUNCTIONS AB The Superconductor-Insulator-Superconductor (SIS) tunnel junction is an extremely sensitive heterodyne detector at millimeter and submillimeter wavelengths. The large inherent capacitance associated with this device results in a substantial impedance mismatch with typical antennas and, therefore, requires a tuning circuit for optimum results. At frequencies where waveguide dimensions are realizable, impedance matching can be accomplished by embedding the detector in a waveguide circuit with adjustable waveguide backshorts. At higher frequencies, where waveguide dimensions become prohibitively small, a planar transmission line embedding circuit provides a reasonable alternative. Typically, such planar circuits offer no post-fabrication adjustability, resulting in demanding materials and design requirements. An adjustable planar embedding circuit based on coplanar transmission lines with movable non-contacting shorting elements has been developed. The shorting elements each consist of a thin metallic plate with an optimized arrangement of rectangular holes, placed along the insulated metallic transmission line to provide a periodic variation of the line impedance. A scale model (1-5 GHz) has shown that a large reflection coefficient, \s11\ greater-than-or-equal-to -0.5 dB, can be achieved with these sliding elements. A low frequency tuning circuit incorporating these shorting elements has been tested to demonstrate practical tuning ranges. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP LUBECKE, VM (reprint author), CALTECH,DIV ENGN & APPL SCI,PASADENA,CA 91125, USA. NR 10 TC 2 Z9 2 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 DEC PY 1991 VL 12 IS 12 BP 1387 EP 1397 DI 10.1007/BF01883872 PG 11 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA GU188 UT WOS:A1991GU18800003 ER PT J AU BAILIN, SC GATTIS, RH TRUSZKOWSKI, W AF BAILIN, SC GATTIS, RH TRUSZKOWSKI, W TI A LEARNING-BASED SOFTWARE ENGINEERING ENVIRONMENT FOR REUSING DESIGN KNOWLEDGE SO INTERNATIONAL JOURNAL OF SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING LA English DT Article AB As part of the NASA/Goddard Code 522.3 research program in software engineering, a Knowledge-Based Software Engineering Environment (KBSEE) is being developed. The KBSEE will support a comprehensive artifact-reuse capability and will incorporate knowledge-based concepts such as machine learning and design knowledge capture. The distinguishing features of this work are that it is a systematic approach to the reuse of knowledge, not just of products, and it implements learning as an explicitly supported function in a software engineering environment. Each of these objectives' is currently being pursued in a distinct prototype environment: design knowledge capture and knowledge reuse in KAPTUR (Knowledge Acquisition for Preservation of Tradeoffs and Underlying Rationales), and learning in LEARN (Learning Enhanced Automation of Reuse engineering). Despite their prototype realization in different environments, the integration of these approaches into an overall KBSEE is a key goal of our work. C1 CTA INC,ROCKVILLE,MD 20852. NASA,GODDARD SPACE FLIGHT CTR,DIV DATA SYST TECHNOL,GREENBELT,MD 20771. NR 10 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-1940 J9 INT J SOFTW ENG KNOW JI Int. J. Softw. Eng. Knowl. Eng. PD DEC PY 1991 VL 1 IS 4 BP 351 EP 371 DI 10.1142/S0218194091000251 PG 21 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA HM738 UT WOS:A1991HM73800003 ER PT J AU BRYAN, K AF BRYAN, K TI NUMERICAL RECOVERY OF CERTAIN DISCONTINUOUS ELECTRICAL CONDUCTIVITIES SO INVERSE PROBLEMS LA English DT Article AB The inverse problem of recovering an electrical conductivity of the form gamma(x) = 1 + (k - 1) chi-D on a region-OMEGA subset-of R2 from boundary data is considered, where D subset-of subset-of OMEGA and k is some positive constant. A linearization of the forward problem is formed and used in a least squares output method for approximately solving the inverse problem. Convergence results are proved and some numerical results presented. RP BRYAN, K (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 9 TC 18 Z9 18 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD DEC PY 1991 VL 7 IS 6 BP 827 EP 840 DI 10.1088/0266-5611/7/6/006 PG 14 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA GW921 UT WOS:A1991GW92100006 ER PT J AU FRELK, JJ HAWKINS, W JASTROW, R NIERENBERG, WA SEITZ, F AF FRELK, JJ HAWKINS, W JASTROW, R NIERENBERG, WA SEITZ, F TI NEW LEADERSHIP FOR SPACE EXPLORATION SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Article C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. NASA,GODDARD INST SPACE STUDIES,WASHINGTON,DC 20546. ROCKEFELLER UNIV,NEW YORK,NY 10021. RP FRELK, JJ (reprint author), GEORGE C MARSHALL INST,WASHINGTON,DC, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD WIN PY 1991 VL 7 IS 2 BP 82 EP 86 PG 5 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA ER714 UT WOS:A1991ER71400054 ER PT J AU LEE, JH CONWAY, EJ AF LEE, JH CONWAY, EJ TI POWER LASER BEAMING AND APPLICATIONS IN SPACE SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON LASER M2P CY JUL 09-11, 1991 CL GRENOBLE, FRANCE SP UNIV JOSEPH FOURIER, CNRS, DEF RES ESTAB TORONTO, CEA, LETI, MAIRIE GRENOBLE, COHERENT SCI, HAMAMATSU, JOBIN YVON, MELLES GRIOT, OPTILAS ID YAG LASER AB A brief overview of the concept of power laser beaming in space and its applications are presented. A direct solar-pumped iodine laser with the iodide t-C4F9I lasant is described as an example of the power laser system. RP LEE, JH (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,MAIL STOP 493,HAMPTON,VA 23665, USA. NR 11 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 DEC PY 1991 VL 1 IS C7 BP 715 EP 719 DI 10.1051/jp4:19917194 PG 5 WC Physics, Multidisciplinary SC Physics GA JJ314 UT WOS:A1991JJ31400144 ER PT J AU MYERS, LP WALSH, KR AF MYERS, LP WALSH, KR TI PERFORMANCE IMPROVEMENTS OF AN F-15 AIRPLANE WITH AN INTEGRATED ENGINE-FLIGHT CONTROL-SYSTEM SO JOURNAL OF AIRCRAFT LA English DT Article AB An integrated flight and propulsion control system has been developed and flight demonstrated on the NASA Ames-Dryden F-15 research aircraft. The highly integrated digital control (HIDEC) system provides additional engine thrust by increasing engine pressure ratio (EPR) at intermediate and afterburning power. The amount of EPR uptrim is modulated based on airplane maneuver requirements, flight conditions, and engine information. Engine thrust was increased as much as 10.5% at subsonic flight conditions by uptrimming EPR. The additional thrust significantly improved aircraft performance. Rate of climb was increased 14% at 40,000 ft and the time to climb from 10,000 to 40,000 ft was reduced 13%. A 14% increase in acceleration at 40,000 ft and 24% increase at 50,000 ft was obtained at intermediate and maximum power, respectively. The HIDEC logic performed fault free. No engine anomalies were encountered for EPR increases up to 12% and for angles of attack and sideslip of 32 and 11 deg, respectively. RP MYERS, LP (reprint author), NASA,AMES RES CTR,EDWARDS AFB,CA 93523, USA. NR 0 TC 0 Z9 1 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 DEC PY 1991 VL 28 IS 12 BP 812 EP 817 DI 10.2514/3.46103 PG 6 WC Engineering, Aerospace SC Engineering GA GZ901 UT WOS:A1991GZ90100004 ER PT J AU WHITMORE, SA LEONDES, CT AF WHITMORE, SA LEONDES, CT TI PNEUMATIC DISTORTION COMPENSATION FOR AIRCRAFT SURFACE PRESSURE SENSING DEVICES SO JOURNAL OF AIRCRAFT LA English DT Article AB In this paper a technique of compensating for pneumatic distortion in aircraft surface pressure sensing devices is developed. The compensation allows conventional pressure sensing technology to obtain improved unsteady pressure measurements. Pressure distortion caused by frictional attenuation and pneumatic resonance within the sensing system makes obtaining unsteady pressure measurements by conventional sensors difficult. Typically, most of the distortion occurs within the pneumatic tubing used to transmit pressure impulses from the surface of the aircraft to the measurement transducer. This paper develops a second-order distortion model that accurately describes the behavior of the primary wave harmonic of the pneumatic tubing. The model is expressed in state-variable form and is coupled with standard results from minimum-variance estimation theory to develop an algorithm to compensate for the effects of pneumatic distortion. Both postflight and real-time algorithms are developed and evaluated using simulated and flight data. Covariance selection and filter-tuning examples are presented. Results presented verify that, given appropriate covariance magnitudes, the algorithms accurately reconstruct surface pressure values from remotely sensed pressure measurements. RP WHITMORE, SA (reprint author), NASA,AMES RES CTR,DRYDEN FLIGHT RES FACIL,EDWARDS,CA 93523, USA. NR 0 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD DEC PY 1991 VL 28 IS 12 BP 828 EP 836 DI 10.2514/3.46105 PG 9 WC Engineering, Aerospace SC Engineering GA GZ901 UT WOS:A1991GZ90100006 ER PT J AU POINSATTE, PE VANFOSSEN, GJ NEWTON, JE DEWITT, KJ AF POINSATTE, PE VANFOSSEN, GJ NEWTON, JE DEWITT, KJ TI HEAT-TRANSFER MEASUREMENTS FROM A SMOOTH NACA-0012 AIRFOIL SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT 28TH AEROSPACE SCIENCES MEETING CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB Local convective heat transfer coefficients were measured from a smooth NACA 0012 airfoil having a chord length of 0.533 m (21 in.). The measurements were made both in flight on the NASA Lewis Twin Otter icing research aircraft and in the NASA Lewis icing research tunnel (IRT). Flight data were taken for the smooth airfoil at Reynolds numbers based on chord in the range 1.24 x 10(6) to 2.50 x 10(6) and at various angles of attack up to 4 deg. During these flight tests, the freestream velocity turbulence intensity was found to be very low (< 0.1%). Wind tunnel data were acquired in the Reynolds number range 1.20 x 10(6) to 4.52 x 10(6) and at angles of attack from -4 to +8 deg. The turbulence intensity in the IRT was 0.5-0.7% with the cloud-generating sprays off. A direct comparison between the results obtained in flight and in the IRT showed that the higher level of turbulence intensity in the IRT had little effect on the heat transfer for the lower Reynolds number but caused a moderate increase in heat transfer at the higher Reynolds numbers. Turning on the cloud-generating spray nozzle atomizing air in the IRT did not alter the heat transfer. The present data were compared with leading-edge cylinder and flat plate heat transfer correlations that are often used to estimate airfoil heat transfer in computer codes. RP POINSATTE, PE (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,HEAT TRANSFER BRANCH,CLEVELAND,OH 44135, USA. NR 0 TC 4 Z9 5 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 DEC PY 1991 VL 28 IS 12 BP 892 EP 898 DI 10.2514/3.46114 PG 7 WC Engineering, Aerospace SC Engineering GA GZ901 UT WOS:A1991GZ90100015 ER PT J AU POINSATTE, PE VANFOSSEN, GJ DEWITT, KJ AF POINSATTE, PE VANFOSSEN, GJ DEWITT, KJ TI ROUGHNESS EFFECTS ON HEAT-TRANSFER FROM A NACA-0012 AIRFOIL SO JOURNAL OF AIRCRAFT LA English DT Note RP POINSATTE, PE (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,HEAT TRANSFER BRANCH,CLEVELAND,OH 44135, 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 DEC PY 1991 VL 28 IS 12 BP 908 EP 911 DI 10.2514/3.46116 PG 4 WC Engineering, Aerospace SC Engineering GA GZ901 UT WOS:A1991GZ90100017 ER PT J AU REID, MB AF REID, MB TI ELECTRON-BEAM EMITTANCE GROWTH IN THIN FOILS - A BETATRON FUNCTION-ANALYSIS SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID GAS AB The emittance of an electron beam increases due to multiple scattering when passing through one or more thin foils. The effect of a given foil on a beam's emittance is dependent on whether the beam is diverging, converging, or at a waist. A method for calculating the growth in emittance using betatron functions is presented. The technique provides a full description of the beam in phase space after a thin scatterer. RP REID, MB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 7 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD DEC 1 PY 1991 VL 70 IS 11 BP 7185 EP 7187 DI 10.1063/1.349761 PG 3 WC Physics, Applied SC Physics GA GU049 UT WOS:A1991GU04900087 ER PT J AU PARAZYNSKI, SE HARGENS, AR TUCKER, B ARATOW, M STYF, J CRENSHAW, A AF PARAZYNSKI, SE HARGENS, AR TUCKER, B ARATOW, M STYF, J CRENSHAW, A TI TRANSCAPILLARY FLUID SHIFTS IN TISSUES OF THE HEAD AND NECK DURING AND AFTER SIMULATED MICROGRAVITY SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE EDEMA; TRANSCAPILLARY PRESSURES; HEAD-DOWN TILT; INTERSTITIAL FLUID PRESSURES; COLLOID OSMOTIC PRESSURES; HYDROSTATIC PRESSURE GRADIENT; ORTHOSTASIS ID CAPILLARY PRESSURES; MUSCLE; WEIGHTLESSNESS AB To understand the mechanism, magnitude, and time course of facial puffiness that occurs in microgravity, seven male subjects were tilted 6-degrees head-down for 8 h, and all four Starling transcapillary pressures were directly measured before, during, and after tilt. Head-down tilt (HDT) caused facial edema and a significant elevation of microvascular pressures measured in the lower lip: capillary pressures increased from 27.7 +/- 1.5 mmHg (mean +/- SE) pre-HDT to 33.9 +/- 1.7 mmHg by the end of tilt. Subcutaneous and intramuscular interstitial fluid pressures in the neck also increased as a result of HDT, whereas interstitial fluid colloid osmotic pressures remained unchanged. Plasma colloid osmotic pressure dropped significantly by 4 h of HDT (21.5 +/- 1.5 mmHg pre-HDT to 18.2 +/- 1.9 mmHg), suggesting a transition from fluid filtration to absorption in capillary beds between the heart and feet during HDT. After 4 h of seated recovery from HDT, microvascular pressures in the lip (capillary and venule pressures) remained significantly elevated by 5-8 mmHg above baseline values. During HDT, urine output was 126.5 ml/h compared with 46.7 ml/h during the control baseline period. These results suggest that facial edema resulting from HDT is caused primarily by elevated capillary pressures and decreased plasma colloid osmotic pressures. The negativity of interstitial fluid pressures above heart level also has implications for maintenance of tissue fluid balance in upright posture. C1 NASA,AMES RES CTR,DIV LIFE SCI,239-11,MOFFETT FIELD,CA 94035. NR 31 TC 64 Z9 69 U1 0 U2 3 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 DEC PY 1991 VL 71 IS 6 BP 2469 EP 2475 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA GW105 UT WOS:A1991GW10500056 PM 1778948 ER PT J AU GROGAN, DW AF GROGAN, DW TI SELECTABLE MUTANT PHENOTYPES OF THE EXTREMELY THERMOPHILIC ARCHAEBACTERIUM SULFOLOBUS-ACIDOCALDARIUS SO JOURNAL OF BACTERIOLOGY LA English DT Note ID BACTERIA; NUCLEOSIDES; ORGANISMS; GENUS; DNA AB As a first step toward developing the genetic potential of extremely thermophilic archaebacteria, mutant strains of Sulfolobus acidocaldarius were selected by plating cells directly on solid medium containing one of several growth inhibitors. Three spontaneous resistance phenotypes were observed (5-fluorouracil resistance, novobiocin resistance, and L-ethionine resistance), each at a different average frequency. Characterization of representative strains showed each of the three mutant phenotypes to provide a potentially useful genetic marker. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 12 TC 31 Z9 32 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0021-9193 J9 J BACTERIOL JI J. Bacteriol. PD DEC PY 1991 VL 173 IS 23 BP 7725 EP 7727 PG 3 WC Microbiology SC Microbiology GA GR594 UT WOS:A1991GR59400049 PM 1938972 ER PT J AU ZEMKE, WT STWALLEY, WC LANGHOFF, SR VALDERRAMA, GL BERRY, MJ AF ZEMKE, WT STWALLEY, WC LANGHOFF, SR VALDERRAMA, GL BERRY, MJ TI RADIATIVE TRANSITION-PROBABILITIES FOR ALL VIBRATIONAL LEVELS IN THE X1-SIGMA+ STATE OF HF SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIPOLE-MOMENT FUNCTIONS; HYDROGEN-FLUORIDE; EINSTEIN COEFFICIENTS; DF; MOLECULES; MATRIX; BAND; HCL AB Recent analyses have led to an experimentally based potential energy curve for the ground state of HF which includes nonadiabatic corrections and which joins smoothly to the long-range potential at an accurately determined dissociation limit (D(e) = 49 362 +/- 5 cm-1). Using this potential curve and a new ab initio dipole moment function (in excellent agreement with experiment), accurate radiative transition probabilities among all vibrational levels (upsilon = 0-19 known, upsilon = 20 predicted) of the ground state of HF have been calculated for selected rotational quantum numbers. Comparisons of Einstein A spontaneous emission coefficients, dipole moment absorption matrix elements, and Herman-Wallis factors for absorption bands are presented. C1 UNIV IOWA,CTR LASER SCI & ENGN,DEPT CHEM,IOWA CITY,IA 52242. UNIV IOWA,DEPT PHYS,IOWA CITY,IA 52242. WARTBURG COLL,DEPT CHEM,WAVERLY,IA 50677. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. HOUSTON AREA RES CTR,LASER APPLICAT RES CTR,THE WOODLANDS,TX 77381. RICE UNIV,DEPT CHEM,HOUSTON,TX 77251. RICE UNIV,RICE QUANTUM INST,HOUSTON,TX 77251. NR 34 TC 62 Z9 64 U1 0 U2 5 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 DEC 1 PY 1991 VL 95 IS 11 BP 7846 EP 7853 DI 10.1063/1.461313 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GR665 UT WOS:A1991GR66500005 ER PT J AU NORWOOD, K ALI, A NG, CY AF NORWOOD, K ALI, A NG, CY TI A PHOTOELECTRON-PHOTOION COINCIDENCE STUDY OF H2O, D2O, AND (H2O)2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID EXCITED-STATES; IONIZATION; MOLECULES; SPECTRUM; IONS; SPECTROSCOPY; LIFETIMES; DIMER; N2O AB Photoelectron-photoion coincidence (PEPICO) data for OH+ (OD+), H+ (D+), and H2O+ (D2O+) from H2O (D2O) have been obtained in the region of 625-700 angstrom. The PEPICO measurements allow the construction of breakdown diagrams for the unimolecular dissociation of energy-selected H2O+ and D2O+ in the B2B2 state. The breakdown diagrams for H2O+ (B2B2) and D2O+ (B2B2) in the internal energy range of 129-166 kcal/mol are essentially identical. The branching ratios observed for H+ (D+) are higher than those reported previously. About 3%-5% of stable H2O+ (D2O+) is observed in the time scale of almost-equal-to 10-mu-s. These stable H2O+ (D2O+) ions are attributed to ultrafast B2B2 --> A2A1 nonradiative relaxation followed by the radiative stabilization from H2O+ (A2A1) [D2O+ (A2A1)] to H2O+ (X2B1) [D2O+ (X2B1)]. This observation also supports that the formation of H+ (D+) via the H2O+ (A2A1) [D2O+ (A2A1)] state is a viable process. The relative state-selected cross sections for the reaction H2O+ (X2B1,A2A1; nu-1, nu-2) + H2O --> H3O+ + H at center-of-mass collision energies less-than-or-equal-to 1.9 eV have been examined using an effusive beam arrangement. Experiment evidence supports that vibrational and electronic excitations suppress the cross section of the latter reaction. We have also performed PEPICO measurements of the processes, (H2O)2 + h-nu --> (H2O)2+ + e- and H3O+ + OH + e-, in the region of 1020-1110 angstrom. The sums of the PEPICO intensities for H3O+ and (H2O)2+ at corresponding photoionization wavelengths yield the photoelectron spectrum for (H2O)2. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NASA,GODDARD SPACE FLIGHT CTR,ASTROCHEM BRANCH,GREENBELT,MD 20771. RP NORWOOD, K (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 28 TC 28 Z9 28 U1 0 U2 14 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 DEC 1 PY 1991 VL 95 IS 11 BP 8029 EP 8037 DI 10.1063/1.461334 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GR665 UT WOS:A1991GR66500026 ER PT J AU PARTRIDGE, H BAUSCHLICHER, CW LANGHOFF, SR TAYLOR, PR AF PARTRIDGE, H BAUSCHLICHER, CW LANGHOFF, SR TAYLOR, PR TI THEORETICAL-STUDY OF THE LOW-LYING BOUND-STATES OF O2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; ELECTRONIC-STRUCTURE CALCULATIONS; ATOMIC NATURAL ORBITALS; CONFIGURATION INTERACTION; GENERAL CONTRACTION; NIGHTGLOW; N-2; EXCITATION; OXYGEN; O-2 AB Ab initio results are presented for the low-lying bound states of O2 that dissociate to ground-state atoms. Spectroscopic constants and dissociation energies (D(e)) are reported for the X 3-SIGMA-g-, a 1-DELTA-g, b 1-SIGMA-g+, c 1-SIGMA-u-, A' 3-DELTA-u, A 3-SIGMA-u+, 3-PI-u, 5-SIGMA-u-, 5-PI-u, and 5-PI-g states. For the first six states, which have been experimentally characterized, we obtain accurate results at the multireference configuration-interaction level after correction for higher excitations. For example, our computed D(e) value for the X 3-SIGMA-g- state corrected for basis-set superposition error is only 0.7 kcal/mol less than the experimental value. The 5-PI-g state is estimated to have a D(e) of 0.16 +/- 0.03 eV, suggesting that the importance of this state in the nightglow should perhaps be reconsidered. C1 ELORET INST,PALO ALTO,CA 94303. RP PARTRIDGE, H (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 39 TC 74 Z9 74 U1 0 U2 6 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 DEC 1 PY 1991 VL 95 IS 11 BP 8292 EP 8300 DI 10.1063/1.461309 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GR665 UT WOS:A1991GR66500053 ER PT J AU YEE, HC SWEBY, PK GRIFFITHS, DF AF YEE, HC SWEBY, PK GRIFFITHS, DF TI DYNAMIC APPROACH STUDY OF SPURIOUS STEADY-STATE NUMERICAL-SOLUTIONS OF NONLINEAR DIFFERENTIAL-EQUATIONS .1. THE DYNAMICS OF TIME DISCRETIZATION AND ITS IMPLICATIONS FOR ALGORITHM DEVELOPMENT IN COMPUTATIONAL FLUID-DYNAMICS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID REACTION-DIFFUSION; BIOLOGICAL POPULATIONS; PARAMETRIC-EXCITATION; MULTIPLE SOLUTIONS; PERIODIC-SOLUTIONS; STABLE POINTS; CHAOS; SCHEMES; SYSTEMS; FLOW C1 UNIV READING, DEPT MATH, READING RG6 2AX, ENGLAND. UNIV DUNDEE, DEPT MATH SCI, DUNDEE DD1 4HN, SCOTLAND. RP YEE, HC (reprint author), NASA, AMES RES CTR, DIV FLUID DYNAM, MOFFETT FIELD, CA 94035 USA. NR 120 TC 68 Z9 69 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC PY 1991 VL 97 IS 2 BP 249 EP 310 DI 10.1016/0021-9991(91)90001-2 PG 62 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA GU727 UT WOS:A1991GU72700001 ER PT J AU SOGA, T GEORGE, T JIMBO, T UMENO, M AF SOGA, T GEORGE, T JIMBO, T UMENO, M TI NUCLEATION MECHANISMS FOR COMPOUND SEMICONDUCTORS GROWN ON SI BY MOCVD SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON VAPOUR GROWTH AND EPITAXY CY JUL 14-17, 1991 CL NAGOYA, JAPAN SP JAPANESE ASSOC CRYSTAL GROWTH, JAPAN SOC APPL PHYS, INT ORG CRYSTAL GROWTH ID CHEMICAL VAPOR-DEPOSITION AB The influence of growth parameters on the initial stage of heteroepitaxial growth of GaP, GaAs and AlAs on (100) Si substrates was examined. GaP and GaAs grow on Si in three-dimensional growth mode, forming well separated islands. However, such islands were observed to be contiguous in the case of AlAs growth on Si. The island density was seen to be proportional to the growth rate. GaAs and GaP exhibit very different growth behavior with increasing V/III flux ratio. Misorientation of the Si substrate does not appear to affect the island densities. Possible mechanisms for this growth behavior, based on cluster formation and migration, are discussed for the growth of these compound semiconductors on Si. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP SOGA, T (reprint author), NAGOYA INST TECHNOL,DEPT ELECT & COMP ENGN,GOKISO CHO,SHOWA KU,NAGOYA,AICHI 466,JAPAN. NR 6 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 DEC PY 1991 VL 115 IS 1-4 BP 418 EP 422 DI 10.1016/0022-0248(91)90778-4 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA HF187 UT WOS:A1991HF18700075 ER PT J AU STEINER, B DOBBYN, RC BLACK, D BURDETTE, H KURIYAMA, M SPAL, R SIMCHICK, R FRIPP, A AF STEINER, B DOBBYN, RC BLACK, D BURDETTE, H KURIYAMA, M SPAL, R SIMCHICK, R FRIPP, A TI HIGH-RESOLUTION X-RAY-DIFFRACTION IMAGING OF LEAD TIN TELLURIDE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID SYNCHROTRON RADIATION; TOPOGRAPHY AB High resolution X-ray diffraction images of two directly comparable crystals of lead tin telluride, one Bridgman-grown on Space Shuttle STS 61A and the other terrestrially Bridgman-grown under similar conditions from identical material, present different subgrain structure. In the terrestrial, sample 1 the appearance of an elaborate array of subgrains is closely associated with the intrusion of regions that are out of diffraction in all of the various images. The formation of this elaborate subgrain structure is inhibited by growth in microgravity. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP STEINER, B (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 6 TC 1 Z9 1 U1 0 U2 2 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 DEC PY 1991 VL 114 IS 4 BP 707 EP 714 DI 10.1016/0022-0248(91)90420-A PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA GV933 UT WOS:A1991GV93300024 ER PT J AU DUYAR, A ELDEM, V MERRILL, WC GUO, TH AF DUYAR, A ELDEM, V MERRILL, WC GUO, TH TI STATE-SPACE REPRESENTATION OF THE OPEN-LOOP DYNAMICS OF THE SPACE-SHUTTLE MAIN ENGINE SO JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME LA English DT Article ID LINEAR-MULTIVARIABLE SYSTEMS; SIMPLE PARAMETER-ESTIMATION; PSEUDO-CANONICAL FORMS; IDENTIFIABLE PARAMETRIZATIONS; MODELS AB A parameter and structure estimation technique for multivariable systems is used to obtain state space representation of open loop dynamics of the space shuttle main engine (SSME). The parametrization being used is both minimal and unique. The simplified linear models may be used for fault detection studies and control system design and development. C1 FLORIDA ATLANTIC UNIV,DEPT MECH ENGN,BOCA RATON,FL 33431. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 18 TC 5 Z9 5 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-0434 J9 J DYN SYST-T ASME JI J. Dyn. Syst. Meas. Control-Trans. ASME PD DEC PY 1991 VL 113 IS 4 BP 684 EP 690 DI 10.1115/1.2896475 PG 7 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA HP702 UT WOS:A1991HP70200020 ER PT J AU VASQUEZ, RP FOOTE, MC BAJUK, L HUNT, BD AF VASQUEZ, RP FOOTE, MC BAJUK, L HUNT, BD TI VALENCE BAND AND BA CORE LEVEL STUDY OF CHEMICALLY-ETCHED YBA2CU3O7-DELTA SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article ID HIGH-TC SUPERCONDUCTOR; ELECTRONIC-STRUCTURE; SINGLE-CRYSTALS; PHOTOEMISSION SPECTROSCOPY; THIN-FILMS; YBA2CU3O6.9; ENERGIES; SURFACES; SHIFTS; STATES AB Orthorhombic and tetragonal YBa2Cu3O7-delta (o-YBCO and t-YBCO) thin films have been chemically etched with Br2 in absolute ethanol and the surfaces characterized by X-ray photoelectron spectroscopy. The Ba4d spectrum for o-YBCO is consistent with a single chemical state and does not exhibit the higher binding energy surface species reported in the literature for cleaved crystals. The Fermi edge for chemically-etched o-YBCO remains clearly detectable at room temperature in vacuum on a time scale of days, in contrast to the surface degradation reported for cleaved crystals on a time scale of hours. These differences are attributed to the surface termination of cleaved crystals with Ba-O planes, which have a different coordination than in the bulk and are reactive, while chemically-etched YBCO is known to be terminated with Cu-O planes. Comparison of the Ba4d core levels and BaMNN Auger peaks for o-YBCO and t-YBCO shows that the observed 1.0 eV core level binding energy difference is not due to a difference in final state relaxation, and therefore must result from differences in the initial state, most likely electrostatic in origin. Cu3d-O2p pi-bonding states in Cu-O chains in the o-YBCO valence band are identified by comparison with the valence bands of other high temperature superconductors and of t-YBCO. RP VASQUEZ, RP (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 36 TC 23 Z9 23 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD DEC PY 1991 VL 57 IS 3-4 BP 317 EP 329 DI 10.1016/0368-2048(91)80018-P PG 13 WC Spectroscopy SC Spectroscopy GA GY987 UT WOS:A1991GY98700006 ER PT J AU SHEETS, P HOOPES, J MELSON, W MCKEE, B SEVER, T MUELLER, M CHENAULT, M BRADLEY, J AF SHEETS, P HOOPES, J MELSON, W MCKEE, B SEVER, T MUELLER, M CHENAULT, M BRADLEY, J TI PREHISTORY AND VOLCANISM IN THE ARENAL AREA, COSTA-RICA SO JOURNAL OF FIELD ARCHAEOLOGY LA English DT Article C1 UNIV KANSAS,LAWRENCE,KS 66045. SMITHSONIAN INST,DEPT MINERAL SCI,WASHINGTON,DC 20560. NASA,STENNIS SPACE CTR,EARTH RESOURCES LAB,NSTL STN,MS. SAN JUAN COLL,CULTURAL RESOURCES MANAGEMENT PROGRAM,FARMINGTON,NM. RP SHEETS, P (reprint author), UNIV COLORADO,DEPT ANTHROPOL,CAMPUS BOX 233,BOULDER,CO 80309, USA. NR 57 TC 8 Z9 9 U1 0 U2 1 PU JOURNAL FIELD ARCHAEOLOGY PI BOSTON PA BOSTON UNIV 675 COMMUNWEALTH AVE, BOSTON, MA 02215 SN 0093-4690 J9 J FIELD ARCHAEOL JI J. Field Archaeol. PD WIN PY 1991 VL 18 IS 4 BP 445 EP 465 DI 10.2307/530407 PG 21 WC Archaeology SC Archaeology GA GQ071 UT WOS:A1991GQ07100003 ER PT J AU VASTANO, JA MOSER, RD AF VASTANO, JA MOSER, RD TI SHORT-TIME LYAPUNOV EXPONENT ANALYSIS AND THE TRANSITION TO CHAOS IN TAYLOR-COUETTE FLOW SO JOURNAL OF FLUID MECHANICS LA English DT Article ID STRANGE ATTRACTORS; VORTEX FLOW; NUMERICAL-METHOD; TURBULENCE; SIMULATION; DIMENSION; SYSTEM; SERIES; WAVE AB Short-time Lyapunov exponent analysis is a new approach to the study of the stability properties of unsteady flows. At any instant in time the Lyapunov perturbations are the set of infinitesimal perturbations to a system state that will grow the fastest in the long term. Knowledge of these perturbations can allow one to determine the instability mechanisms producing chaos in the system. This new method should prove useful in a wide variety of chaotic flows. Here it is used to elucidate the physical mechanism driving weakly chaotic Taylor-Couette flow. Three-dimensional, direct numerical simulations of axially periodic Taylor-Couette flow are used to study the transition from quasi-periodicity to chaos. A partial Lyapunov exponent spectrum for the flow is computed by simultaneously advancing the full solution and a set of perturbations. The axial wavelength and the particular quasi-periodic state are chosen to correspond to the most complete experimental studies of this transition. The computational results are consistent with available experimental data, both for the flow characteristics in the quasi-periodic regime and for the Reynolds number at which transition to chaos is observed. The dimension of the chaotic attractor near onset is estimated from the Lyapunov exponent spectrum using the Kaplan-Yorke conjecture. This dimension estimate supports the experimental observation of low-dimensional chaos, but the dimension increases more rapidly away from the transition than is observed in experiments. Reasons for this disparity are given. Short-time Lyapunov exponent analysis is used to show that the chaotic state studied here is caused by a Kelvin-Helmholtz-type instability of the outflow boundary jet of the Taylor vortices. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP VASTANO, JA (reprint author), STANFORD UNIV,CTR TURBULENCE RES,STANFORD,CA 94305, USA. NR 30 TC 28 Z9 28 U1 0 U2 6 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 DEC PY 1991 VL 233 BP 83 EP 118 DI 10.1017/S002211209100040X PG 36 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GX041 UT WOS:A1991GX04100005 ER PT J AU ANTONIA, RA KIM, J BROWNE, LWB AF ANTONIA, RA KIM, J BROWNE, LWB TI SOME CHARACTERISTICS OF SMALL-SCALE TURBULENCE IN A TURBULENT DUCT FLOW SO JOURNAL OF FLUID MECHANICS LA English DT Article ID NEAR-WALL REGION; BOUNDARY-LAYER; CHANNEL FLOW; DISSIPATION; WAKE; FLUCTUATIONS; ISOTROPY AB The fine-scale structure of turbulence in a fully developed turbulent duct flow is examined by considering the three-dimensional velocity derivative field obtained from direct numerical simulations at two relatively small Reynolds numbers. The magnitudes of all mean-square derivatives (normalized by wall variables) increase with the Reynolds number, the increase being largest at the wall. These magnitudes are not consistent with the assumption of local isotropy except perhaps near the duct centre-line. When the assumption of local isotropy is relaxed to one of local axisymmetry, or invariance with respect to rotation about a coordinate axis (here chosen in the streamwise direction), satisfactory agreement is indicated by the data outside the wall region. Support for axisymmetry is demonstrated by anisotropy invariant maps of the dissipation and vorticity tensors. The departure from axisymmetry does not appear to be affected by the Reynolds number. Expressions are proposed for approximations to the average energy dissipation and components of the mean-square vorticity. These proposals should allow these quantities to be measured accurately, at least in the present flow. C1 NASA,AMES RES CTR,CTR TURBULENCE RES,MOFFETT FIELD,CA 94035. RP ANTONIA, RA (reprint author), UNIV NEWCASTLE,DEPT MECH ENGN,NEWCASTLE,NSW 2308,AUSTRALIA. OI Kim, John/0000-0002-6369-9264 NR 33 TC 95 Z9 95 U1 0 U2 8 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD DEC PY 1991 VL 233 BP 369 EP 388 DI 10.1017/S0022112091000526 PG 20 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GX041 UT WOS:A1991GX04100017 ER PT J AU MILLER, TL REYNOLDS, ND AF MILLER, TL REYNOLDS, ND TI A STUDY OF BAROCLINIC INSTABILITY IN A CYLINDRICAL ANNULUS WITH THE TEMPERATURE-GRADIENT IMPOSED ON THE LOWER SURFACE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID ROTATING FLUID; CONVECTION; DRIVEN AB Laboratory experiments and numerical modelling studies have been performed for a rotating, thermally driven fluid system in a cylindrical annulus with a vertical rotation vector and axis of symmetry. The thermal forcing was through the imposition of an axisymmetric temperature gradient on a thermally conducting lower boundary, with additional heating through the outer sidewall. The upper and inner walls were nominally insulating. Flow patterns were observed in the experiments through the use of small, reflective flakes (Kalliroscope) in the working fluid, which was water. The rotation rate and temperature difference were varied to construct a regime diagram in thermal Rossby number-Taylor number space. The curve separating axisymmetric flow from wave flow is 'knee-shaped', similar to the side-heated and -cooled baroclinic annulus which has been extensively investigated previously. Very near the transition curve, the initial wavenumber persists indefinitely, but well into the wave regime the initial wavenumber is higher than the equilibrated value. Far enough into the wave regime, the initial waves have wavenumbers several times that of the equilibrated value, and the initial disturbances form near the outer wall very early in the experiment. Numerical studies indicate that these waves are effective in distributing heat and that they occur in a region of positive static stability. These waves rapidly grow inward to fill the annulus and reduce in number as weaker waves are absorbed by the stronger ones. The period of transition between these waves and the equilibrated long-wave pattern is characterized by irregular flow. Closer to the transition curve, the temporal transition to longer waves as the flow equilibrates is simpler, with initial waves filling the annulus. In that case, the transition is characterized by a slow process of individual waves weakening and merging with adjacent waves. C1 UNIV ALABAMA,DEPT MATH SCI,HUNTSVILLE,AL 35899. RP MILLER, TL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV EARTH SCI & APPLICAT,HUNTSVILLE,AL 35812, USA. NR 16 TC 1 Z9 1 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD DEC PY 1991 VL 233 BP 495 EP 518 DI 10.1017/S0022112091000575 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GX041 UT WOS:A1991GX04100022 ER PT J AU MEHTA, UB AF MEHTA, UB TI SOME ASPECTS OF UNCERTAINTY IN COMPUTATIONAL FLUID-DYNAMICS RESULTS SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Uncertainties are inherent in computational fluid dynamics (CFD). These uncertainties need to be systematically addressed and managed. Sources of these uncertainties are identified and some aspects of uncertainty analysis are discussed. Some recommendations are made for quantification of CFD uncertainties. A practical method of uncertainty analysis is based on sensitivity analysis. When CFD is used to design fluid dynamic systems, sensitivity-uncertainty analysis is essential. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 39 TC 20 Z9 20 U1 0 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD DEC PY 1991 VL 113 IS 4 BP 538 EP 543 DI 10.1115/1.2926512 PG 6 WC Engineering, Mechanical SC Engineering GA HP712 UT WOS:A1991HP71200003 ER PT J AU ANTONIA, RA BISSET, DK KIM, J AF ANTONIA, RA BISSET, DK KIM, J TI AN EDDY VISCOSITY CALCULATION METHOD FOR A TURBULENT DUCT FLOW SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID LOW REYNOLDS-NUMBER; PRESSURE-GRADIENTS; BOUNDARY-LAYERS; CHANNEL FLOW; FORMULA; WALL AB The mean velocity profile across a fully developed turbulent duct flow is obtained from an eddy viscosity relation combined with an empirical outer region wake function. Results are in good agreement with experiments and with direct numerical simulations in the same flow at two Reynolds numbers. In particular, the near-wall trend of the Reynolds shear stress and its variation with Reynolds number are similar to those of the simulations. The eddy viscosity method is more accurate than previous mixing length or implicit function methods. C1 UNIV NEWCASTLE, DEPT MECH ENGN, NEWCASTLE, NSW 2308, AUSTRALIA. NASA, AMES RES CTR, CTR TURBULENCE RES, MOFFETT FIELD, CA 94035 USA. NR 17 TC 5 Z9 5 U1 0 U2 0 PU ASME PI NEW YORK PA TWO PARK AVE, NEW YORK, NY 10016-5990 USA SN 0098-2202 EI 1528-901X J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD DEC PY 1991 VL 113 IS 4 BP 616 EP 619 DI 10.1115/1.2926524 PG 4 WC Engineering, Mechanical SC Engineering GA HP712 UT WOS:A1991HP71200015 ER PT J AU DURBIN, PA SPEZIALE, CG AF DURBIN, PA SPEZIALE, CG TI LOCAL ANISOTROPY IN STRAINED TURBULENCE AT HIGH REYNOLDS-NUMBERS SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Note ID FLOWS AB It is shown that the hypothesis of local isotropy is implausible in the presence of significant mean rates of strain. In fact, it appears that in uniform shear flow near equilibrium, local isotropy can never constitute a systematic approximation, even in the limit of infinite Reynolds number. An estimate of the level of mean strain rate for which local isotropy is formally a good approximation is provided. C1 STANFORD UNIV,CTR TURBULENCE RES,STANFORD,CA 94035. NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. NR 16 TC 62 Z9 62 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD DEC PY 1991 VL 113 IS 4 BP 707 EP 709 DI 10.1115/1.2926540 PG 3 WC Engineering, Mechanical SC Engineering GA HP712 UT WOS:A1991HP71200029 ER PT J AU BEHANNON, KW BURLAGA, LF HEWISH, A AF BEHANNON, KW BURLAGA, LF HEWISH, A TI STRUCTURE AND EVOLUTION OF COMPOUND STREAMS AT LESS-THAN-OR-EQUAL-TO-1-AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY SHOCKS; SOLAR-WIND; HELIOS SPACECRAFT; SCINTILLATION; DISTURBANCES; SIMULATION; TRANSIENT; DENSITY; EARTH; AU AB Two cases of compound stream formation and evolution at heliocentric distances of less-than-or-equal-to 1 AU have been studied using simultaneous data from both multipoint in situ and global sources. The sequences of events analyzed occurred around December 16, 1978, and February 19, 1979, respectively. The sources of the multipoint observations were Helios A, Helios B, IMP 8, and ISEE 3. The global observations were obtained by interplanetary scintillation analysis of radio sources. It was found that the radio and in situ data complemented each other and that both were needed for a unique interpretation of complex, time-dependent flows. The cases studied show that a single corotating stream can interact with different transient flows at different times, and a single transient flow can interact with different corotating streams at different times. In each instance, a compound stream is formed. This work further shows that the cosmic ray intensity at a point depends on the global compound stream configuration in the vicinity of the point. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV CAMBRIDGE,CAVENDISH LAB,MULLARD RADIO ASTRON OBSERV,CAMBRIDGE CB3 0HE,ENGLAND. RP BEHANNON, KW (reprint author), 3145 FARNBOROUGH COURT,SILVER SPRING,MD 20906, USA. NR 34 TC 41 Z9 41 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 DEC 1 PY 1991 VL 96 IS A12 BP 21213 EP 21225 DI 10.1029/91JA02267 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800022 ER PT J AU WOO, R SCHWENN, R AF WOO, R SCHWENN, R TI COMPARISON OF DOPPLER SCINTILLATION AND INSITU SPACECRAFT PLASMA MEASUREMENTS OF INTERPLANETARY DISTURBANCES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; SOLAR-WIND; RADIO SCATTERING; SLOW SHOCKS; TRANSIENTS AB Since 1979 the radio path of the Pioneer Venus orbiter (PVO) spacecraft has spent considerable time probing the near-Sun solar wind off the limbs of the Sun. On occasion, Helios 1 has also been in position above the Sun's limb at the same solar longitude to simultaneously observe in situ the solar wind plasma. These fortuitous circumstances, along with the availability of near-continuous measurements, have made it possible for the first time to carry out detailed comparisons between Doppler scintillation and in situ plasma measurements and to improve our understanding of Doppler scintillation transients. During a combined observing period of nearly 3 months in 1981-1982 near solar maximum, 22 transients were observed by PVO and 23 shocks were observed by Helios 1. On the basis of a comparison of mass flux density and rms Doppler scintillations, we find that at least 84% of the transients are shocks, while at least 90% of the shocks are transients. Hence there is a near one-to-one correspondence between transients and interplanetary shocks. Although the temporal profiles of Doppler scintillation and mass flux density are similar, the magnitudes of the Doppler scintillation transients may not simply reflect those of mass flux density. Only one pronounced solar wind event that was observed in the mass flux density measurements showed no signature in the scintillation data; field and particle measurements by Helios 1 suggest that it is a noncompressive density enhancement and/or a magnetic cloud. One of the scintillation transients that is not a fast-mode shock appears to correspond to a slow shock. However, when scintillations alone are available, slow shocks may be difficult to identify. Shock speeds based on transit times between the PVO radio scintillation path and the Helios 1 spacecraft are consistent with those from the in situ plasma measurements and indicate shock deceleration in essentially all cases. A significant consequence of this investigation is that Doppler scintillation measurements can now be used by themselves to detect and locate interplanetary shocks near the Sun with a relatively high degree of confidence and hence can be used to conduct useful correlative studies in the future with other solar and interplanetary observations. C1 MAX PLANCK INST AERON,W-3411 KATLENBORG LINDAU,GERMANY. RP WOO, R (reprint author), CALTECH,JET PROP LAB,MS 238 737,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 23 Z9 23 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 DEC 1 PY 1991 VL 96 IS A12 BP 21227 EP 21244 DI 10.1029/91JA02266 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800023 ER PT J AU KLIORE, AJ LUHMANN, JG AF KLIORE, AJ LUHMANN, JG TI SOLAR-CYCLE EFFECTS ON THE STRUCTURE OF THE ELECTRON-DENSITY PROFILES IN THE DAYSIDE IONOSPHERE OF VENUS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DAYTIME IONOSPHERE; WIND INTERACTION; RADIO; IONOPAUSE; PEAK AB Since 1975, United States and Soviet Venus-orbiting spacecraft have carried out more than 190 radio occultation measurements of the vertical electron density structure of the dayside ionosphere of Venus: 148 of these have been produced by the Pioneer Venus orbiter between 1979 and 1989; Venera 9 and 10 provided 13 measurements in 1975; and Venera 15 and 16 made 31 measurements in 1983. These measurements were made at various times of the solar cycle, including solar maximum and solar minimum. It has therefore been possible to observe the changes in the electron density structure of the dayside ionosphere of Venus that were brought about by changing solar activity. Some of the resulting observations are as follows: (1) The ionopause height is generally low for values of the solar zenith angle below about 50-degrees regardless of the phase in the solar cycle. (2) At solar maximum, and at times of intermediate solar activity, the ionopause height for solar zenith angles greater than about 50-degrees is highly variable, ranging from a minimum of about 200 km to a maximum of more than 1000 km. (3) At times of solar minimum the great majority of all ionopause heights for all solar zenith angles are uniformly low, lying between 200 and 300 km, with the notable exception of three Venera 9 and 10 measurements. The compressed nature of the Venus ionosphere at solar minimum is most likely produced by permeation of the ionosphere by the solar wind magnetic field, which occurs when the solar wind dynamic pressure exceeds the ionospheric plasma pressure. This happens at times of solar maximum at low solar zenith angles and when the solar wind dynamic pressure is exceptionally high. At solar minimum the Venus ionosphere, like the Martian ionosphere at all phases of the solar cycle, does not appear to have sufficient thermal pressure to balance the incident solar wind pressure. C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP KLIORE, AJ (reprint author), CALTECH,JET PROP LAB,MS 161-228,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 TC 22 Z9 22 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 DEC 1 PY 1991 VL 96 IS A12 BP 21281 EP 21289 DI 10.1029/91JA01829 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800027 ER PT J AU GREBOWSKY, JM CURTIS, SA BRACE, LH AF GREBOWSKY, JM CURTIS, SA BRACE, LH TI SMALL-SCALE PLASMA IRREGULARITIES IN THE NIGHTSIDE VENUS IONOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DENSITY-FLUCTUATIONS; ORBITER AB The individual volt-ampere curves from the Pioneer Venus orbiter electron temperature probe showed evidence for small-scale density irregularities, or short-period plasma waves, in regions of the nightside ionosphere where the orbiter electric field detector observed waves in its 100-Hz channel. A survey of the nightside volt-ampere curves has revealed several hundred examples of such irregularities (approximately 2% of all the current-voltage (I-V) sweeps from below 2000 km and 7% of those below 200 km). The I-V structures correspond to plasma density structures with spatial scale sizes in the range of about 100-2000 m, or alternatively they could be viewed as waves having frequencies extending toward 100 Hz. They are often seen as isolated events, with spatial extent along the orbit frequently less than 80 km. The density irregularities or waves occur in or near prominent gradients in the ambient plasma concentrations both at low altitudes where molecular ions are dominant and at higher altitudes in regions of reduced plasma density where O+ is the major ion. Electric field 100-Hz bursts occur simultaneously, with the majority of the structured I-V curves providing demonstrative evidence that at least some of the E field signals are produced within the ionosphere. Potential sources for the irregularities are extraionospheric particle precipitation and spatial structures and turbulence resulting from the day to night ion transport within the ionosphere. C1 UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. NASA,GODDARD SPACE FLIGHT CTR,RIGSHOSP LAB,GREENBELT,MD 20771. RP GREBOWSKY, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 914,GREENBELT,MD 20771, USA. RI Grebowsky, Joseph/I-7185-2013 NR 19 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD DEC 1 PY 1991 VL 96 IS A12 BP 21347 EP 21359 DI 10.1029/91JA02374 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800034 ER PT J AU MANDT, ME KAN, JR AF MANDT, ME KAN, JR TI ELECTROSTATIC POTENTIAL JUMP ACROSS FAST-MODE COLLISIONLESS SHOCKS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EARTHS BOW SHOCK; PERPENDICULAR SHOCKS; RESOLVED LAYER; HIGH-BETA; FIELD; ELECTRONS; IONS; WAVE AB The electrostatic potential jump across fast-mode collisionless shocks is examined by comparing published observations, hybrid simulations, and a simple model in order to better characterize its dependence on the various shock parameters. In all three, it is assumed that the electrons can be described by an isotropic power law equation of state. The observations show that the cross-shock potential jump correlates well with the shock strength but shows very little correlation with other shock parameters. Assuming that the electrons obey an isotropic power law equation of state, the correlation of the potential jump with the shock strength follows naturally from the increased shock compression (DELTA-n) and an apparent dependence of the power law exponent on the Mach number which the observations indicate. We find that including a Mach number dependence for the power law exponent in the electron equation of state in our simple model, as suggested by the observations, produces a potential jump which better fits the observations. On the basis of the simulation results and theoretical estimates of the cross-shock potential, we also discuss how the cross-shock potential might be expected to depend on the other shock parameters, namely, beta-e, and theta-Bn. Given the broad range of parameters lumped together in the observational results, we feel that the qualitative agreement between them and the simulations is quite good and can be used to better elucidate the nature of the discrepancies. C1 UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99775. UNIV ALASKA,DEPT PHYS,FAIRBANKS,AK 99775. RP MANDT, ME (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 692,GREENBELT,MD 20771, USA. NR 22 TC 3 Z9 3 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 DEC 1 PY 1991 VL 96 IS A12 BP 21391 EP 21395 DI 10.1029/91JA02405 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800037 ER PT J AU MOSES, SL CORONITI, FV GREENSTADT, EW TSURUTANI, BT AF MOSES, SL CORONITI, FV GREENSTADT, EW TSURUTANI, BT TI POSSIBLE WAVE AMPLITUDES IN SHOCKS IN THE SOLAR CORONA - PREDICTIONS FOR SOLAR PROBE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID STELLAR WINDS; BOW SHOCK; MODEL; FLOW; SUN AB Shocks and Alfven turbulence are frequently invoked as mechanisms to heat the solar corona and accelerate the solar wind. A primary objective of the Solar Probe Mission is to detect and characterize these nonthermal dissipation and energization processes. Although the solar wind in the corona is usually assumed to be sub-Alfvenic, temporal and spatial variability in the plasma parameters could lead to conditions under which weak, fast mode shocks might form. ISEE 3 data from the flanks of the Earth's bow shock show that even low Mach number, quasi-parallel shocks generate large-amplitude Alfven turbulence with delta-B/B of the order of 1, and intense high-frequency electrostatic plasma waves. Using a model of the corona and scaling parameters to those expected in the regions to be traversed by Solar Probe (r greater-than-or-equal-to 4 R(s)), we suggest it is possible that such shocks might produce Alfven turbulence with magnetic field amplitudes up to the order of 0.1 G and electric field amplitudes up to the order of 1 V/m; electrostatic waves near 100 kHz may have amplitudes of 0.1 V/m. Since the shock-generated Alfven waves would be Doppler shifted to frequencies of a few kilohertz because of the high spacecraft velocity at perihelion, detection of these waves imposes severe requirements on the designs of plasma wave and magnetic field sensors on Solar Probe. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP MOSES, SL (reprint author), TRW CO INC,SPACE & TECHNOL GRP,1 SPACE PK,R1-1170,REDONDO BEACH,CA 90278, USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD DEC 1 PY 1991 VL 96 IS A12 BP 21397 EP 21401 DI 10.1029/91JA02268 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU768 UT WOS:A1991GU76800038 ER PT J AU WHITTENBERGER, JD AF WHITTENBERGER, JD TI PROPERTIES OF PURE NICKEL AFTER LONG-TERM EXPOSURES TO LIOH AND VACUUM AT 775-K SO JOURNAL OF MATERIALS ENGINEERING LA English DT Article AB The solid to liquid phase transformation of LiOH at 744 K is considered to be an ideal candidate thermal energy storage (TES) mechanism for a Rankine heat engine based solar dynamic system operating at approximately 682 K. While pure nickel is thought to be a suitable containment material for LiOH, long term containment is of concern because molten hydroxides are usually corrosive. Two lots of commercially pure nickel (both with chemistries corresponding to Ni-201) have been exposed to molten LiOH, its vapor, and vacuum at 775 K for periods ranging from 50 to 5000 hr, and simple mechanical property measurements (77 to 900 K tensile and 750 K creep rupture) of exposed materials have been undertaken. Comparison of the weight gain data, microstructures, and tensile and creep rupture properties indicates that little, if any, difference in behavior can be ascribed to exposure to any of the three environments. Thus it can be concluded that Ni is a suitable containment material for a LiOH thermal energy storage system. RP WHITTENBERGER, JD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 0931-7058 J9 J MATER ENG PD DEC PY 1991 VL 13 IS 4 BP 257 EP 271 DI 10.1007/BF02834028 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA GU303 UT WOS:A1991GU30300002 ER PT J AU RINSLAND, CP SMITH, MAH DEVI, VM BENNER, DC AF RINSLAND, CP SMITH, MAH DEVI, VM BENNER, DC TI MEASUREMENTS OF LORENTZ-BROADENING COEFFICIENTS AND PRESSURE-INDUCED LINE SHIFT COEFFICIENTS IN THE NU-2 BAND OF HD O-16 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Note ID ATMOSPHERIC GASES; SPECTRA; H2O; AIR C1 COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23185. RP RINSLAND, CP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665, USA. NR 16 TC 16 Z9 17 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD DEC PY 1991 VL 150 IS 2 BP 640 EP 646 DI 10.1016/0022-2852(91)90255-9 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA GQ232 UT WOS:A1991GQ23200018 ER PT J AU MAY, RD PETERSON, DB AF MAY, RD PETERSON, DB TI OBSERVATION OF THE O-O STRETCH FUNDAMENTAL-BAND OF HO2NO2 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Letter ID ACID HOONO2; SPECTRUM; STATE RP MAY, RD (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 12 TC 6 Z9 6 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD DEC PY 1991 VL 150 IS 2 BP 647 EP 649 DI 10.1016/0022-2852(91)90256-A PG 3 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA GQ232 UT WOS:A1991GQ23200019 ER PT J AU WATERS, JF SUTTER, JK MEADOR, MAB BALDWIN, LJ MEADOR, MA AF WATERS, JF SUTTER, JK MEADOR, MAB BALDWIN, LJ MEADOR, MA TI ADDITION CURING THERMOSETS ENDCAPPED WITH 4-AMINO [2.2] PARACYCLOPHANE SO JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY LA English DT Article DE POLYIMIDES; CYCLOPHANE; ENDCAP; 4-AMINO [2.2] PARA CYCLOPHANE ID POLYIMIDES AB A new family of addition curing polyimides were prepared that contained 4-amino [2.2]-paracyclophane as the endcap. An improved synthesis of the endcap 4-amino-[2.2]cyclophane was accomplished increasing the yield to 60% and simplifying the procedure. DSC and rheological analysis of endcapped polyimide oligomers confirmed that the onset for polymerization of the ethylene bridge was 250-degrees-C C-13 CP/MAS NMR was used to determine the structural changes of the oligomers after thermal treatment. The cyclophane capped polyimides were successfully compression molded to form void free neat resin specimens. T(g)'s as high as 353-degrees-C were obtained by thermomechanical analysis for postcured samples. Preliminary thermal stability studies (TGA) suggest that these resins have a high onset of decomposition ranging from 549 to 567-degrees-C. C1 CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. OI Meador, Mary Ann/0000-0003-2513-7372 NR 21 TC 20 Z9 24 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-624X J9 J POLYM SCI POL CHEM JI J. Polym. Sci. Pol. Chem. PD DEC PY 1991 VL 29 IS 13 BP 1917 EP 1924 DI 10.1002/pola.1991.080291311 PG 8 WC Polymer Science SC Polymer Science GA GQ622 UT WOS:A1991GQ62200011 ER PT J AU HAGEDORN, NH AF HAGEDORN, NH TI THE AU-CATHODE IN THE SYSTEM LI2CO3-CO2-CO AT 800-DEGREES-C TO 900-DEGREES-C SO JOURNAL OF POWER SOURCES LA English DT Article AB The lithium-CO2 battery has recently been proposed as an advanced concept for missions to Mars or Venus, planets with carbon dioxide atmospheres. This article discusses the initial evaluation of gold as a catalyst for the cathodic reduction of carbon dioxide in molten lithium carbonate. An attempt is then made to rationalize the experimental results by proposing a phenomenological model for the sequence of reactions at and around the electrode. Finally, inferences are made as to the viability of gold as a cathode catalyst for the proposed battery. RP HAGEDORN, NH (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 10 TC 0 Z9 0 U1 0 U2 2 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 DEC 1 PY 1991 VL 36 IS 3 BP 205 EP 218 DI 10.1016/0378-7753(91)87002-S PG 14 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600002 ER PT J AU LOYSELLE, PL SHAN, X CORNILSEN, BC REID, MA AF LOYSELLE, PL SHAN, X CORNILSEN, BC REID, MA TI RAMAN SPECTRAL OBSERVATION OF A NEW PHASE OBSERVED IN NICKEL ELECTRODES CYCLED TO FAILURE SO JOURNAL OF POWER SOURCES LA English DT Article AB A 'new phase' is reported in nickel electrodes from Ni-H-2 boilerplate cells which were cycled to failure in electrolyte of variable KOH concentration (21-36%). Raman spectra clearly show the presence of this phase, and these spectra have been used to estimate the amounts present on these electrodes. Ten of twelve electrodes examined contain this new phase. The cycle life at higher KOH concentrations (31 and 36%) was greatly reduced, and nickel electrodes from these cells exhibited extensive amounts of this new phase. The presence of this 'new phase' correlates with cell failure defined by low end of discharge voltages. It is proposed that the lowered capacity and failure of these electrodes was caused by loss of active mass and formation of a phase with reduced electrochemical activity. These results indicate that formation of this new phase is accelerated at higher KOH concentrations. C1 MICHIGAN TECHNOL UNIV,1400 TOWNSEND DR,HOUGHTON,MI 49931. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 5 TC 3 Z9 3 U1 0 U2 0 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 DEC 1 PY 1991 VL 36 IS 3 BP 279 EP 284 DI 10.1016/0378-7753(91)87007-X PG 6 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600007 ER PT J AU REID, MA LOYSELLE, PL AF REID, MA LOYSELLE, PL TI IMPEDANCES OF NICKEL ELECTRODES CYCLED IN VARIOUS KOH CONCENTRATIONS SO JOURNAL OF POWER SOURCES LA English DT Article ID HYDROGEN CELLS; CADMIUM CELLS; LIFE AB Recent work has shown that Ni-H-2 cells cycled in 26% KOH have much longer lives than those cycled in other concentrations. As Part of an ongoing program to try to correlate the impedances of nickel electrodes with their life and performance, impedances were measured of a number of electrodes from these tests that had been cycled in concentrations from 21 to 36% KOH. These had been cycled under double-time LEO conditions at 80% DOD to failure. Cell life ranged from about 1000 to 40000 cycles. After cycling ten times to reduce possible changes due to storage, impedances were measured at five voltages corresponding to low states of charge. The results were analyzed using a standard circuit model including a Warburg impedance term. Lower kinetic resistances and Warburg slopes were found for several electrodes which had been cycled in 26% KOH even though they had been cycled for a much longer time than the others. Interpretation of the data is complicated by the fact that the cycle lives, storage times and failure mechanisms varied. Several other circuit models have also been examined, but the best correlations with life were found with parameters obtained from the simple model. RP REID, MA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 15 TC 12 Z9 12 U1 1 U2 3 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 DEC 1 PY 1991 VL 36 IS 3 BP 285 EP 298 DI 10.1016/0378-7753(91)87008-Y PG 14 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600008 ER PT J AU SARANGAPANI, S FORCHIONE, J GRIFFITH, A LACONTI, AB BALDWIN, R AF SARANGAPANI, S FORCHIONE, J GRIFFITH, A LACONTI, AB BALDWIN, R TI SOME RECENT STUDIES WITH THE SOLID-IONOMER ELECTROCHEMICAL CAPACITOR SO JOURNAL OF POWER SOURCES LA English DT Article ID DOUBLE-LAYER AB Giner, Inc. has developed a high-energy-density, all-solid-ionomer electrochemical capacitor, completely free of liquid electrolyte. The novel features of this device include (i) a three-dimensional metal oxide-particulate-ionomer composite electrode structure and (ii) a unitized repeating cell element. The composite electrode structures are bonded to opposite sides of a thin sheet of a solid proton-conducting ionomer membrane and for-m an integrally bonded membrane and electrode assembly (MEA). Individual MEAs can be stacked in series as bipolar elements to form a multiple cell device. The discharge characteristics and energy storage properties of these devices are described. Typical capacitance measured for a unit cell is 1 F/cm2. Life testing of a multicell capacitor on an intermittent basis has shown, that over a 10 000 h period, the capacitance and resistance of the cell has remained invariant. There has been no maintenance required on the device since it was fabricated. Other multicell units of shorter life duration have exhibited similar reliable performance characteristics. Recent work has focused on increasing the capacitance of the unitized structure and improving the low-temperature characteristics. The approaches and experimental results will be presented. Some possible advanced NASA applications for these unique all-solid-ionomer devices will be discussed. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SARANGAPANI, S (reprint author), GINER INC,14 SPRING ST,WALTHAM,MA 02254, USA. NR 27 TC 4 Z9 4 U1 0 U2 4 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 DEC 1 PY 1991 VL 36 IS 3 BP 341 EP 361 DI 10.1016/0378-7753(91)87011-Y PG 21 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600011 ER PT J AU GAHN, RF AF GAHN, RF TI PERFORMANCE OF A DUAL ANODE NICKEL HYDROGEN CELL SO JOURNAL OF POWER SOURCES LA English DT Article AB An experimental study was conducted to characterize the voltage performance of a nickel-hydrogen cell containing a hydrogen electrode on both sides of the nickel electrode. The dual anode cell was compared with a conventional single anode cell using the same nickel electrode. Higher discharge voltages and lower charge voltages were obtained with the dual anode cell during constant current discharges to 10C, pulse discharges to 8C and polarization measurements at 50% state-of-charge. RP GAHN, RF (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD DEC 1 PY 1991 VL 36 IS 3 BP 363 EP 373 DI 10.1016/0378-7753(91)87012-Z PG 11 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600012 ER PT J AU RATNAKUMAR, BV ATTIA, AI HALPERT, G AF RATNAKUMAR, BV ATTIA, AI HALPERT, G TI SODIUM METAL CHLORIDE BATTERY RESEARCH AT THE JET-PROPULSION-LABORATORY (JPL) SO JOURNAL OF POWER SOURCES LA English DT Article ID CATHODES; CELL AB Sodium-metal chloride batteries have certain distinct advantages over sodium-sulfur batteries such as increased safety, inherent overcharge capability and lower operating temperatures. Two systems, i.e. Na/FeCl2 and Na/NiCl2 were developed extensively elsewhere and evaluated for various applications including electric vehicles and space. Their performance has been very encouraging and prompted a detailed fundamental study on these cathodes here at the Jet Propulsion Laboratory. A brief review of our studies on these new cathode materials is presented here. The initial efforts focussed on the methods of fabrication of the electrodes and their electrochemical characterization. Subsequent studies were aimed at establishing the reaction mechanism, determining the kinetics and identifying the rate-limiting processes in the reduction of metal chloride cathodes. Nickel chloride emerged from these studies as the most promising candidate material and was taken up for further detailed study on its passivation-a rate limiting process-under different experimental conditions. Also, the feasibility of using copper chloride, which is expected to have higher energy density, has been assessed. Based on the criteria established from the voltammetric response of FeCl2, NiCl2 and CuCl2, several other transition metal chlorides were screened. Of these, molybdenum and cobalt chlorides appear promising. RP RATNAKUMAR, BV (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 14 TC 14 Z9 14 U1 1 U2 12 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 DEC 1 PY 1991 VL 36 IS 3 BP 385 EP 394 DI 10.1016/0378-7753(91)87014-3 PG 10 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600014 ER PT J AU SURAMPUDI, S SHEN, DH HUANG, CK DELIGIANNIS, F ATTIA, A HALPERT, G AF SURAMPUDI, S SHEN, DH HUANG, CK DELIGIANNIS, F ATTIA, A HALPERT, G TI ADVANCES IN LI-TIS2 CELL TECHNOLOGY SO JOURNAL OF POWER SOURCES LA English DT Article ID TEMPERATURE AB JPL is involved in a NASA sponsored program to develop ambient temperature secondary cells for future space missions. After several years of research on various cathode materials, titanium disulfide (TiS2) Was selected in view of its intrinsic reversibility and high faradaic utilization. In the last two years, efforts have been focussed on improving the cycle life of the system and developing 1 A h cells. Several approaches including the use of mixed solvent electrolytes, the operation of cells at low temperature, and the cycling of cells under different voltage limits, were initially examined to improve the cycle life performance of the Li-TiS2 system. Spiral wound 1 A h cells fabricated incorporating the improvements from the above studies have delivered more than 600 cycles at 50% DOD. Work is in progress to identify alternate anode materials that can improve the cycle life of the cells to 1000 cycles at 50% DOD. This paper summarizes the advances made in the Li-TiS2 technology at JPL since 1989. RP SURAMPUDI, S (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 2 Z9 2 U1 1 U2 13 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 DEC 1 PY 1991 VL 36 IS 3 BP 395 EP 402 DI 10.1016/0378-7753(91)87015-4 PG 8 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600015 ER PT J AU WARSHAY, M AF WARSHAY, M TI PROCEEDINGS OF THE 3RD SPACE ELECTROCHEMICAL RESEARCH AND TECHNOLOGY CONFERENCE - NASA LEWIS-RESEARCH-CENTER CLEVELAND, OH, USA, APRIL 9-10, 1991 - FOREWORD SO JOURNAL OF POWER SOURCES LA English DT Editorial Material RP WARSHAY, M (reprint author), NASA,LEWIS RES CTR,21000 BROOKPART RD,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD DEC 1 PY 1991 VL 36 IS 3 BP R11 EP R12 DI 10.1016/0378-7753(91)87001-R PG 2 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA GT256 UT WOS:A1991GT25600001 ER PT J AU CHOU, SH LOESCH, AZ AF CHOU, SH LOESCH, AZ TI SUPERCRITICAL BAROCLINIC DISTURBANCES UNDER THE INFLUENCE OF TOPOGRAPHY SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID FINITE-AMPLITUDE INTERACTIONS; WEATHER REGIMES; WAVES; DYNAMICS; DISSIPATION; FLOW; INSTABILITY; EQUILIBRIA; STATIONARY; BLOCKING AB Nonlinear evolution of baroclinic waves in the presence of surface topography is investigated in an Eady model modified to include Ekman dissipation and sloping horizontal boundaries. The topographic for-m drag competes with baroclinicity for the control of amplitude evolution and propagation characteristics of the various disturbance modes. The effectiveness of the topography to phase lock and equilibrate a given mode versus that of baroclinicity to propagate and vacillate that mode depends on the topographic height, its zonal structure, and the level of supercriticality. When topography is sinusoidal and of the same wavelength as the baroclinically most unstable mode, it induces a short-period amplitude modulation whose envelope represents the baroclinic evolution. The dynamics of this modulation is explored analytically. When the sinusoidal topography is of a longer zonal wavelength, a "mixed" wave state persists with amplitude dominance shifting between the topographic mode and the baroclinic mode, depending on the relative strength of form drag and baroclinicity. When topography is a superposition of the most unstable wavelength and a longer one, amplitude dominance and phase locking tend to shift to the mode associated with the "taller" mountain harmonic. When the harmonic structure of topography corresponds to that observed at 35-degrees-N, amplitude dominance is concentrated in the longest seven wavelengths. Model results are also compared, in appropriate parameter limits, with near-resonance asymptotic results and annulus experiments. C1 SUNY ALBANY,DEPT ATMOSPHER SCI,ALBANY,NY 12222. RP CHOU, SH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV EARTH & APPLICAT,E542,HUNTSVILLE,AL 35812, USA. NR 30 TC 1 Z9 1 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 DEC 1 PY 1991 VL 48 IS 23 BP 2461 EP 2475 DI 10.1175/1520-0469(1991)048<2461:SBDUTI>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX805 UT WOS:A1991GX80500001 ER PT J AU RANDEL, WJ LAIT, LR AF RANDEL, WJ LAIT, LR TI DYNAMICS OF THE 4-DAY WAVE IN THE SOUTHERN-HEMISPHERE POLAR STRATOSPHERE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MEAN-FLOW INTERACTION; BAROTROPIC INSTABILITY; WINTER; STRATOPAUSE AB Dynamics of the 4-day wave in the Southern Hemisphere polar stratosphere is investigated using horizontal wind and temperature data. These were derived from synoptic maps of satellite-measured brightness temperatures, which were generated using the fast Fourier synoptic mapping technique of Salby. Circulation statistics from these data are compared to those from the National Meteorological Center (NMC) operational stratospheric analyses, demonstrating improvements afforded by detailed treatment of asynoptic sampling effects. The 4-day wave is isolated using temporally filtered data. Several events of wave growth and decay are observed in the upper stratosphere during August 1980. Derived zonal-mean and eddy statistics suggest that the 4-day wave results from an instability of the zonal-mean flow near 55-degree-60-degrees-S, at and above 1 mb. Inspection of climatological data suggests the source of the instability to be the "double-jet" structure in the upper stratosphere and mesosphere (the subtropical mesospheric jet near 30-degrees-S and the high-latitude extension of the polar night jet near 70-degrees-S). Contribution of the 4-day wave to the general circulation of the stratosphere is discussed: one feature attributable to the 4-day wave is a region of positive EP flux divergence in the upper stratosphere near 50-degrees-60-degrees-S. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ATMOSPHERES LAB,GREENBELT,MD 20771. RP RANDEL, WJ (reprint author), NATL CTR ATMOSPHER RES,POB 3000,BOULDER,CO 80307, USA. RI Randel, William/K-3267-2016 OI Randel, William/0000-0002-5999-7162 NR 21 TC 17 Z9 17 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD DEC 1 PY 1991 VL 48 IS 23 BP 2496 EP 2508 DI 10.1175/1520-0469(1991)048<2496:DOTDWI>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX805 UT WOS:A1991GX80500004 ER PT J AU MANNEY, GL MECHOSO, CR ELSON, LS FARRARA, JD AF MANNEY, GL MECHOSO, CR ELSON, LS FARRARA, JD TI PLANETARY-SCALE WAVES IN THE SOUTHERN-HEMISPHERE WINTER AND EARLY SPRING STRATOSPHERE - STABILITY ANALYSIS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID BAROTROPIC INSTABILITY; BAROCLINIC INSTABILITY; SATELLITE; NORTHERN; STATES; JET AB Eastward-traveling waves 2 and 3 are frequently observed to grow in the Southern Hemisphere stratosphere during late winter and early spring. Observations show times when wave 2 growth appears to be confined to the stratosphere. This suggests that instability is one in situ mechanism that should be considered. The stability of stratospheric flows derived from data is examined during some of these times, using several linear models of quasigeostrophic instability. Unstable modes of both wave 2 and wave 3 have periods and spatial structures similar to observations. Wave 2 and wave 3 momentum fluxes are similar in observations and model results and are consistent with the transfer of kinetic energy from the zonal-mean flow to the wave. When a barotropic model with a zonally symmetric basic flow is used, wave 3 is usually most unstable. Including a stationary wave 1 in the basic flow destabilizes both wave 2 and wave 3, but has little effect on their periods or spatial structures. When a zonally symmetric flow with realistic meridional and vertical structure is used, resulting unstable modes have shorter periods and slower growth rates than for barotropic flows. Wave 2 is usually more unstable than wave 3 when realistic vertical structure is included. The similarity between observed fields and model results in a number of cases when wave 2 appears to grow within the stratosphere suggests that in situ instabilities play a role in the evolution of the eastward-traveling wave 2 characteristic of the Southern Hemisphere winter and early spring stratosphere. C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. RP MANNEY, GL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 20 TC 14 Z9 14 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD DEC 1 PY 1991 VL 48 IS 23 BP 2509 EP 2523 DI 10.1175/1520-0469(1991)048<2509:PSWITS>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX805 UT WOS:A1991GX80500005 ER PT J AU MCNALLAN, MJ LEE, YY CHANG, YW JACOBSON, NS DOYCHAK, J AF MCNALLAN, MJ LEE, YY CHANG, YW JACOBSON, NS DOYCHAK, J TI OXIDATION-CHLORINATION OF BINARY NI-CR ALLOYS IN FLOWING AR-O2-CL2 GAS-MIXTURES AT 1200-K SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID HIGH-TEMPERATURE CORROSION; OXYGEN; NICKEL; BEHAVIOR; CHROMIUM; OXIDE AB Nickel-chromium alloys are resistant to oxidation because of the selective oxidation of chromium to form a protective Cr2O3 scale. In chlorine-containing environments, volatile corrosion products can also be formed. The mixed oxidation-chlorination of Ni-4.5%Cr, Ni-13.8%Cr, and Ni-26.5%Cr (by weight) alloys in Ar-O2-Cl2 gas mixtures has been investigated using thermogravimetric analysis and atmospheric-pressure sampling mass spectrometry, followed by examination of the corrosion products using scanning electron microscopy and x-ray diffraction analysis. The overall kinetics of the corrosion are affected by the relative amounts of oxides and chlorides formed and the composition of the oxide corrosion products. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP MCNALLAN, MJ (reprint author), UNIV ILLINOIS,DEPT CEMM,CHICAGO,IL 60680, USA. RI Jacobson, Nathan/A-9411-2009 NR 24 TC 13 Z9 13 U1 0 U2 1 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD DEC PY 1991 VL 138 IS 12 BP 3692 EP 3696 DI 10.1149/1.2085481 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA GT518 UT WOS:A1991GT51800036 ER PT J AU YOSHIZAWA, A AF YOSHIZAWA, A TI STATISTICAL MODELING OF COMPRESSIBLE TURBULENCE - SHOCK-WAVE TURBULENCE INTERACTIONS AND BUOYANCY EFFECTS SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article ID SHEAR FLOWS; CONVECTION; VISCOSITY AB A mass-weighted mean compressible turbulence model is presented with the aid of the results from a two-scale DIA. This model aims at dealing with two typical aspects in compressible flows: the interaction of a shock wave with turbulence in high-speed flows and strong buoyancy effects in thermally-driven flows as in stellar convection and conflagration. The former is taken into account through the effect of turbulent dilatation that is related to the density fluctuation and leads to the enhanced kinetic-energy dissipation. The latter is incorporated through the interaction between the gravitational and density-fluctuation effects. C1 NASA,LEWIS RES CTR,INST COMPUTAT MECH PROPULS,CLEVELAND,OH 44135. RP YOSHIZAWA, A (reprint author), UNIV TOKYO,INST IND SCI,7-22-1 ROPPONGI,MINATO KU,TOKYO 106,JAPAN. NR 19 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOCIETY JAPAN PI TOKYO PA KIKAI-SHINKO BUILDING, 3-5-8 SHIBA-KOEN, MINATO-KU, TOKYO 105, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD DEC PY 1991 VL 60 IS 12 BP 4119 EP 4126 DI 10.1143/JPSJ.60.4119 PG 8 WC Physics, Multidisciplinary SC Physics GA GX192 UT WOS:A1991GX19200025 ER PT J AU SEKANINA, Z AF SEKANINA, Z TI ENCKE, THE COMET SO JOURNAL OF THE ROYAL ASTRONOMICAL SOCIETY OF CANADA LA English DT Article AB The history of observations, orbital investigations, and physical studies of Encke's comet is reviewed and its significance in the quest for understanding the nature and evolution of comets is discussed. Highlighted on the background of general progress achieved are the major developments that took place over the past two centuries, such as J.F. Encke's work on the comet's anomalous orbital motion and his hypothesis of a resisting interplanetary medium; F.W. Bessel's critique of the hypothesis and his remarkable concept of recoil forces exerted on cometary nuclei; O. Backlund's arguments for apparent discontinuities in the non-gravitational perturbations of the comet's motion and the ultimate abandonment of the concept of a resisting medium; formulation of new ideas after comet theory emerged from a long period of stagnation; the vital role of Encke's comet in F.L. Whipple's icy-conglomerate model; and recent major advances in both physical and dynamical investigations of the comet, including studies of its rotation and precession, the nature of the non-gravitational anomaly, and the evolution of discrete active regions on the nucleus. Finally, prospects for future research are briefly addressed. RP SEKANINA, Z (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 19 Z9 19 U1 0 U2 0 PU ROYAL ASTRON SOC CANADA PI TORONTO PA 136 DUPONT ST, TORONTO ON M5R 1V2, CANADA SN 0035-872X J9 J ROY ASTRON SOC CAN JI J. R. Astron. Soc. Can. PD DEC PY 1991 VL 85 IS 6 BP 324 EP 376 PG 53 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC115 UT WOS:A1991HC11500003 ER PT J AU MITCHELL, BG BRODY, EA HOLMHANSEN, O MCCLAIN, C BISHOP, J AF MITCHELL, BG BRODY, EA HOLMHANSEN, O MCCLAIN, C BISHOP, J TI LIGHT LIMITATION OF PHYTOPLANKTON BIOMASS AND MACRONUTRIENT UTILIZATION IN THE SOUTHERN-OCEAN SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT SYMP ON WHAT CONTROLS PHYTOPLANKTON PRODUCTION IN NUTRIENT-RICH AREAS OF THE OPEN SEA CY FEB 22-24, 1991 CL SAN MARCOS, CA SP AMER SOC LIMNOL & OCEANOG ID MARGINAL ICE-ZONE; ANTARCTIC PHYTOPLANKTON; WEDDELL SEA; MARINE-PHYTOPLANKTON; BLOOM DYNAMICS; SCOTIA SEA; TEMPERATURE; GROWTH; AMMONIUM; NITROGEN AB The Antarctic Circumpolar Current (ACC) is unique in that it has continually high concentrations of major plant nutrients but low phytoplankton biomass. This enigmatic phenomenon is the focus of significant speculation that trace nutrients, including Fe, may limit phytoplankton crop size. Global climatologies indicate that the ACC is a region with low surface temperatures, weak density stratification, little summertime surface solar irradiance, and strong wind stress. These physical phenomena act to limit growth rates of the phytoplankton community. Using a photo-physiological description of phytoplankton growth in a simple one-dimensional ecosystem model forced by observations or climatologies of mixing depth and surface irradiance, we make an evaluation of the potential for massive, nutrient-exhausting, phytoplankton blooms forming in the ACC. The ACC has persistent mixed layers in excess of 50 m. Literature values and model optimization indicate that the minimal aggregate specific loss rate for phytoplankton, including respiration, sinking, and grazing, is approximately 0.2 d-1. For a minimal loss rate and typical physical conditions of stratification and surface irradiance, the model predicts that phytoplankton in the ACC would not utilize > 10% of the available macronutrients. Without a mechanism for increasing the strength of stratification, we predict that massive Fe additions to the Southern Ocean would fail to significantly mitigate the atmospheric CO2 derived from fossil fuel. C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,POLAR RES PROGRAM,LA JOLLA,CA 92093. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. RP MITCHELL, BG (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,DIV MARINE RES,LA JOLLA,CA 92093, USA. NR 71 TC 227 Z9 231 U1 3 U2 25 PU AMER SOC LIMNOLOGY OCEANOGRAPH PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD DEC PY 1991 VL 36 IS 8 BP 1662 EP 1677 PG 16 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA HR981 UT WOS:A1991HR98100012 ER PT J AU BREARLEY, AJ CASANOVA, I MILLER, ML KEIL, K AF BREARLEY, AJ CASANOVA, I MILLER, ML KEIL, K TI MINERALOGY AND POSSIBLE ORIGIN OF AN UNUSUAL CR-RICH INCLUSION IN THE LOS MARTINEZ (L6) CHONDRITE SO METEORITICS LA English DT Article ID CARBONACEOUS CHONDRITES; PLAGIOCLASE; EXSOLUTION; OLIVINE AB During a petrological study of the previously unclassified ordinary chondrite Los Martinez, we discovered a highly unusual Cr-rich inclusion which we believe is unique in both extraterrestrial and terrestrial mineralogy. The inclusion is highly zoned both compositionally and optically, with a Ca-Al rich, cloudy core and an opaque, Cr-Na-rich rim (up to 24 wt.% Cr2O3). Detailed SEM and TEM studies show that the inclusion now consists of a highly zoned, single crystal of plagioclase intergrown with chromium-rich spinel. The spinel has a well-developed crystallographic orientation relationship with the host plagioclase, which indicates that it is the product of exsolution. Although superficially similar to a plagioclase feldspar in composition, in detail the inclusion is Si-deficient and Al-enriched relative to a stoichiometric feldspar. We have not been able to identify a viable precursor mineral phase to the plagioclase-chromite intergrowth and suggest that it may be an unknown metastable phase. The Cr-rich precursors of the inclusion probably have close affinities to the chromite-plagioclase chondrules observed by Ramdohr (1967) in several ordinary chondrites. Based on the zoning in the inclusion, we suggest that it is the product of fractional crystallization from a melt, which may have formed as a liquid condensate, or by melting of solid condensates, in the solar nebula. Subsequent cooling of this melt condensate resulted in crystallization of the, as yet, unidentified phase. After crystallization, the inclusion was probably incorporated into a parent body where it underwent metamorphism and was probably shocked to some degree. During this period of parent body metamorphism, exsolution and decomposition of the unknown precursor occurred to produce the observed intergrowth of plagioclase and chromite. Finally, we have classified Los Martinez as an L6 ordinary chondrite breccia. C1 UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,DEPT GEOL & GEOPHYS,HONOLULU,HI 96822. NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. UNIV NEW MEXICO,DEPT GEOL,ALBUQUERQUE,NM 87131. RP BREARLEY, AJ (reprint author), UNIV NEW MEXICO,INST METEORIT,ALBUQUERQUE,NM 87131, USA. NR 29 TC 11 Z9 11 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 287 EP 300 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900004 ER PT J AU ALLAMANDOLA, LJ AF ALLAMANDOLA, LJ TI INTERSTELLAR ORGANICS AND POSSIBLE CONNECTIONS WITH THE CARBONACEOUS COMPONENTS OF METEORITES AND IDPS SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 1 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 DEC PY 1991 VL 26 IS 4 BP 312 EP 313 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900010 ER PT J AU ALLAMANDOLA, LJ SANDFORD, SA TIELENS, AGGM HERBST, T AF ALLAMANDOLA, LJ SANDFORD, SA TIELENS, AGGM HERBST, T TI METHANOL IN THE SKY WITH DIAMONDS SO METEORITICS LA English DT Meeting Abstract ID INTERSTELLAR DIAMONDS C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. NR 6 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 313 EP 313 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900011 ER PT J AU BACKMAN, DE PARESCE, F AF BACKMAN, DE PARESCE, F TI NEARBY MAIN-SEQUENCE STARS WITH COOL CIRCUMSTELLAR MATERIAL SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FRANKLIN & MARSHALL COLL,DEPT PHYS & ASTRON,LANCASTER,PA 17604. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NR 0 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 314 EP 314 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900015 ER PT J AU BARLOW, NG AF BARLOW, NG TI DEGRADATION STUDIES OF MARTIAN IMPACT CRATERS SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 8 TC 0 Z9 0 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 DEC PY 1991 VL 26 IS 4 BP 315 EP 315 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900017 ER PT J AU BLAKE, DF ALLAMANDOLA, LJ SANDFORD, S FREUND, F AF BLAKE, DF ALLAMANDOLA, LJ SANDFORD, S FREUND, F TI CLATHRATE TYPE-II HYDRATE FORMATION INVACUO UNDER ASTROPHYSICAL CONDITIONS SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,PLANETARY BIOL BRANCH,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,ASTROPHYS BRANCH,MOFFETT FIELD,CA 94035. SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95192. NR 5 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 319 EP 320 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900028 ER PT J AU BOGARD, DD GARRISON, DH AF BOGARD, DD GARRISON, DH TI AR-39-AR-40-AGES OF ACHONDRITES - EVIDENCE FOR A LUNAR-LIKE CATACLYSM SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 3 TC 4 Z9 4 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 320 EP 320 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900030 ER PT J AU BOURCIER, WL ZOLENSKY, ME AF BOURCIER, WL ZOLENSKY, ME TI AQUEOUS ALTERATION ON THE PARENT BODIES OF CARBONACEOUS CHONDRITES - COMPUTER-SIMULATIONS OF LATE-STAGE OXIDATION SO METEORITICS LA English DT Meeting Abstract C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. NR 3 TC 3 Z9 3 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 321 EP 322 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900034 ER PT J AU BREARLEY, AJ CASANOVA, I MILLER, ML KEIL, K AF BREARLEY, AJ CASANOVA, I MILLER, ML KEIL, K TI MINERALOGY OF AN UNUSUAL CR-RICH INCLUSION IN THE LOS MARTINEZ (L6) CHONDRITIC BRECCIA SO METEORITICS LA English DT Meeting Abstract C1 UNIV NEW MEXICO,INST METEORIT,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,DEPT GEOL,ALBUQUERQUE,NM 87131. NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. UNIV HAWAII,SOEST,DIV PLANETARY GEOSCI,HONOLULU,HI 96822. NR 4 TC 14 Z9 14 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 323 EP 323 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900038 ER PT J AU BROWNLEE, DE HORZ, F LAURANCE, M BERNHARD, RP WARREN, J BRADLEY, JP AF BROWNLEE, DE HORZ, F LAURANCE, M BERNHARD, RP WARREN, J BRADLEY, JP TI THE COMPOSITION OF METEOROIDS IMPACTING LDEF SO METEORITICS LA English DT Meeting Abstract C1 UNIV WASHINGTON,DEPT ASTRON,SEATTLE,WA 98195. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. MCCRONE ASSOCIATES,WESTMONT,IL. 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 DEC PY 1991 VL 26 IS 4 BP 325 EP 325 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900042 ER PT J AU BUNCH, T CASSEN, P REYNOLDS, R CHANG, S PODOLAK, M PRIALNIK, D SCHULTZ, P AF BUNCH, T CASSEN, P REYNOLDS, R CHANG, S PODOLAK, M PRIALNIK, D SCHULTZ, P TI COULD CHONDRULE RIMS BE FORMED OR MODIFIED BY PARENT BODY ACCRETION EVENTS SO METEORITICS LA English DT Meeting Abstract ID UNEQUILIBRATED ORDINARY CHONDRITES; ORIGIN; MATRICES C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. TEL AVIV UNIV,IL-69978 TEL AVIV,ISRAEL. BROWN UNIV,PROVIDENCE,RI 02912. NR 8 TC 3 Z9 3 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 326 EP 326 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900044 ER PT J AU CASANOVA, I AF CASANOVA, I TI DISTRIBUTION OF SILICON BETWEEN KAMACITE AND TAENITE SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 5 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 326 EP 327 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900046 ER PT J AU CASSEN, P AF CASSEN, P TI A GUIDE TO THE USE OF THEORETICAL-MODELS OF THE SOLAR NEBULA FOR THE INTERPRETATION OF THE METEORITIC RECORD SO METEORITICS 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 METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 327 EP 327 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900047 ER PT J AU CUZZI, JN CHAMPNEY, JM DOBROVOLSKIS, AR AF CUZZI, JN CHAMPNEY, JM DOBROVOLSKIS, AR TI PARTICLE-GAS DYNAMICS IN THE PROTOPLANETARY NEBULA SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. 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 DEC PY 1991 VL 26 IS 4 BP 329 EP 330 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900055 ER PT J AU DEHART, JM LOFGREN, GE AF DEHART, JM LOFGREN, GE TI LOW-TEMPERATURE ANNEALING AND CATHODOLUMINESCENCE STUDIES OF TYPE-I CHONDRULE ANALOGS SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 2 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 330 EP 330 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900057 ER PT J AU GARRISON, DH BOGARD, DD HERZOG, GF AF GARRISON, DH BOGARD, DD HERZOG, GF TI COSMOGENIC AR-36 FROM NEUTRON-CAPTURE BY CL-35 IN THE CHICO L6 CHONDRITE - ADDITIONAL EVIDENCE FOR LARGE SHIELDING SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RUTGERS STATE UNIV,NEW BRUNSWICK,NJ 08903. NR 6 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 336 EP 336 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900071 ER PT J AU HARPER, CL WIESMANN, H NYQUIST, LE AF HARPER, CL WIESMANN, H NYQUIST, LE TI CS-135 BA-135 - VERY HIGH-PRECISION ISOTOPIC INVESTIGATIONS AND A NEW COSMOCHRONOMETRIC CONSTRAINT ON THE ASTROPHYSICAL SITE OF THE ORIGIN OF THE SOLAR-SYSTEM SO METEORITICS LA English DT Meeting Abstract ID METEORITES C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 5 TC 7 Z9 7 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 DEC PY 1991 VL 26 IS 4 BP 341 EP 342 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900085 ER PT J AU HARVEY, RP SCORE, R AF HARVEY, RP SCORE, R TI DIRECT EVIDENCE OF IN-ICE OR PRE-ICE WEATHERING OF ANTARCTIC METEORITES SO METEORITICS LA English DT Meeting Abstract C1 UNIV TENNESSEE,DEPT GEOL SCI,KNOXVILLE,TN 37996. NASA,LYNDON B JOHNSON SPACE CTR,DIV PLANETARY MAT,HOUSTON,TX 77058. NR 8 TC 12 Z9 12 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 343 EP 344 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900090 ER PT J AU HORZ, F MITTLEFEHLDT, DW SEE, TH AF HORZ, F MITTLEFEHLDT, DW SEE, TH TI DISSEMINATION AND FRACTIONATION OF PROJECTILE MATERIAL IN IMPACT MELTS FROM THE WABAR CRATER, SAUDI-ARABIA SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ESC,HOUSTON,TX 77058. NR 5 TC 2 Z9 2 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 346 EP 347 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900098 ER PT J AU JONES, JH JUREWICZ, AJG LE, L AF JONES, JH JUREWICZ, AJG LE, L TI A LIQUIDUS PHASE-DIAGRAM FOR A PRIMITIVE SHERGOTTITE SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ESC,HOUSTON,TX 77058. NR 4 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 DEC PY 1991 VL 26 IS 4 BP 353 EP 353 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900114 ER PT J AU KARLSSON, HR CLAYTON, RN GIBSON, EK MAYEDA, TK SOCKI, RA AF KARLSSON, HR CLAYTON, RN GIBSON, EK MAYEDA, TK SOCKI, RA TI EXTRATERRESTRIAL WATER OF POSSIBLE MARTIAN ORIGIN IN SNC METEORITES - CONSTRAINTS FROM OXYGEN ISOTOPES SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. LOCKHEED ESC,HOUSTON,TX 77058. NR 5 TC 3 Z9 3 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 354 EP 355 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900118 ER PT J AU KELLER, LP MCKAY, DS AF KELLER, LP MCKAY, DS TI THE ORIGIN OF AMORPHOUS RIMS ON LUNAR PLAGIOCLASE GRAINS SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 12 TC 3 Z9 3 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 355 EP 355 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900119 ER PT J AU KELLER, LP THOMAS, KL MCKAY, DS AF KELLER, LP THOMAS, KL MCKAY, DS TI TRANSMISSION ELECTRON-MICROSCOPY OF AN INTERPLANETARY DUST PARTICLE WITH LINKS TO CI CHONDRITES SO METEORITICS LA English DT Meeting Abstract ID CARBONACEOUS CHONDRITE C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED,HOUSTON,TX 77058. NR 5 TC 3 Z9 3 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 355 EP 356 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900120 ER PT J AU LERNER, NR PETERSON, E CHANG, S AF LERNER, NR PETERSON, E CHANG, S TI EVALUATION OF THE STRECKER SYNTHESIS AS A SOURCE OF AMINO-ACIDS ON CARBONACEOUS CHONDRITES SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 3 TC 0 Z9 0 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 363 EP 363 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900138 ER PT J AU LINDSTROM, DJ AF LINDSTROM, DJ TI MICROPROBE STUDIES OF MICROTOMED PARTICLES OF WHITE DRUSE SALTS IN SHERGOTTITE EETA-79001 SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 5 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 DEC PY 1991 VL 26 IS 4 BP 365 EP 365 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900142 ER PT J AU LINDSTROM, MM AF LINDSTROM, MM TI RELATIONSHIPS AMONG BASALTIC LUNAR METEORITES SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 9 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 DEC PY 1991 VL 26 IS 4 BP 365 EP 365 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900143 ER PT J AU LOFGREN, GE DEHART, JM LANIER, AB AF LOFGREN, GE DEHART, JM LANIER, AB TI DYNAMIC CRYSTALLIZATION CHARACTERISTICS OF ENSTATITE CHONDRITE CHONDRULES SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ESC,HOUSTON,TX 77058. NR 4 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 366 EP 367 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900147 ER PT J AU MCKAY, G LE, L WAGSTAFF, J AF MCKAY, G LE, L WAGSTAFF, J TI OLIVINES IN ANGRITE LEW87051 - PHENOS OR XENOS SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NASA,HOUSTON,TX 77058. NR 5 TC 6 Z9 6 U1 1 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 370 EP 370 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900156 ER PT J AU MITTLEFEHLDT, DW MEYERS, B AF MITTLEFEHLDT, DW MEYERS, B TI PETROLOGY AND GEOCHEMISTRY OF THE EETA79002 DIOGENITE SO METEORITICS LA English DT Meeting Abstract C1 NASA,LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. UNIV ARKANSAS,DEPT AGRON,FAYETTEVILLE,AR 72701. NR 3 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 373 EP 373 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900163 ER PT J AU NYQUIST, LE HARPER, CL WIESMANN, H BANSAL, B SHIH, CY AF NYQUIST, LE HARPER, CL WIESMANN, H BANSAL, B SHIH, CY TI ND-142 ND-144 IN SNCS AND LUNAR-SAMPLES - IMPLICATIONS FOR EARLY DIFFERENTIATION OF A HETEROGENEOUS MARTIAN QUESTIONABLE MANTLE SO METEORITICS LA English DT Meeting Abstract ID PB SYSTEMATICS; EVOLUTION; SHERGOTTY; PLANET; AGE; ND; SR C1 NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. NASA, LYNDON B JOHNSON SPACE CTR, NATL RES COUNCIL, HOUSTON, TX 77058 USA. NASA, LOCKHEED ENGN & SCI CO, HOUSTON, TX 77258 USA. NR 12 TC 13 Z9 13 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 381 EP 381 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900183 ER PT J AU OSTRO, SJ AF OSTRO, SJ TI RADAR CONSTRAINTS ON ASTEROID METAL ABUNDANCES AND METEORITE ASSOCIATIONS SO METEORITICS LA English DT Meeting Abstract C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 2 TC 0 Z9 0 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 381 EP 382 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900185 ER PT J AU PETERSON, E HORZ, F HAYNES, G SEE, T AF PETERSON, E HORZ, F HAYNES, G SEE, T TI MODIFICATION OF AMINO-ACIDS AT SHOCK PRESSURES OF 3 TO 30 GPA - INITIAL RESULTS SO METEORITICS LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NR 3 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 DEC PY 1991 VL 26 IS 4 BP 384 EP 385 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900193 ER PT J AU DIBROZOLO, FR HARRIS, DW CHAKEL, JA FLEMING, RH BUNCH, TE AF DIBROZOLO, FR HARRIS, DW CHAKEL, JA FLEMING, RH BUNCH, TE TI IMAGING ANALYSIS OF LDEF CRATERS SO METEORITICS LA English DT Meeting Abstract C1 CHARLES EVANS & ASSOCIATES,REDWOOD CITY,CA 94063. NASA,AMES RES CTR,MOFFETT FIELD,CA 94034. NR 2 TC 1 Z9 1 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 387 EP 387 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900199 ER PT J AU SEARS, DWG JIE, L BENOIT, PH DEHART, J LOFGREN, GE AF SEARS, DWG JIE, L BENOIT, PH DEHART, J LOFGREN, GE TI A COMPOSITIONAL CLASSIFICATION FOR CHONDRULES SO METEORITICS LA English DT Meeting Abstract C1 UNIV ARKANSAS,DEPT CHEM & BIOCHEM,COSMOCHEM GRP,FAYETTEVILLE,AR 72701. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 393 EP 394 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900216 ER PT J AU SOCKI, RA GIBSON, EK JULL, AJT KARLSSON, HR AF SOCKI, RA GIBSON, EK JULL, AJT KARLSSON, HR TI CARBON AND OXYGEN ISOTOPE COMPOSITION OF CARBONATES FROM AN L6 CHONDRITE - EVIDENCE FOR TERRESTRIAL WEATHERING FROM THE HOLBROOK METEORITE SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. UNIV ARIZONA,NSF FAC RADIOISOTOPE ANAL,TUCSON,AZ 85721. LESC,HOUSTON,TX 77058. NR 6 TC 4 Z9 4 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 396 EP 397 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900223 ER PT J AU STEPINSKI, TF AF STEPINSKI, TF TI MAGNETIZATION OF METEORITES BY DYNAMO-GENERATED MAGNETIC-FIELDS IN THE SOLAR NEBULA SO METEORITICS LA English DT Meeting Abstract C1 NASA,INST LUNAR & PLANETARY,HOUSTON,TX 77058. NR 8 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 DEC PY 1991 VL 26 IS 4 BP 398 EP 398 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900226 ER PT J AU TREIMAN, AH GOODING, JL AF TREIMAN, AH GOODING, JL TI IDDINGSITE IN THE NAKHLA METEORITE - TEM STUDY OF MINERALOGY AND TEXTURE OF PRE-TERRESTRIAL (MARTIAN ALTERATIONS) SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 6 TC 15 Z9 15 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 DEC PY 1991 VL 26 IS 4 BP 402 EP 402 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900237 ER PT J AU WENTWORTH, SJ GOODING, JL AF WENTWORTH, SJ GOODING, JL TI CARBONATE AND SULFATE MINERALS IN THE CHASSIGNY METEORITE SO METEORITICS LA English DT Meeting Abstract C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. NR 7 TC 9 Z9 9 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 408 EP 409 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900253 ER PT J AU ZAHNLE, K AF ZAHNLE, K TI FRACTIONATION OF TERRESTRIAL NEON BY HYDRODYNAMIC HYDROGEN ESCAPE FROM ANCIENT STEAM ATMOSPHERES SO METEORITICS LA English DT Meeting Abstract ID EVOLUTION C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 6 TC 0 Z9 0 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 412 EP 413 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900265 ER PT J AU ZOLENSKY, ME AF ZOLENSKY, ME TI MINERALOGY AND MATRIX COMPOSITION OF CR CHONDRITES RENAZZO AND EET-87770, AND UNGROUPED CHONDRITES ESSEBI AND MAC-87300 SO METEORITICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. NR 2 TC 17 Z9 18 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD DEC PY 1991 VL 26 IS 4 BP 414 EP 414 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HF779 UT WOS:A1991HF77900269 ER PT J AU DAY, CSR DONE, C AF DAY, CSR DONE, C TI A DISK-REFLECTED COMPONENT IN THE SPECTRA OF X-RAY BURSTERS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Note ID COLD MATTER; GALAXIES; EMISSION; NUCLEI AB We show that a disc-reflection component, as seen in AGN, can be detected in the spectrum of X-ray bursts during the burst tail, and speculate on the use of the concomitant absorption edge as a diagnostic of the accretion disc. RP DAY, CSR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI done, chris/D-4605-2016 OI done, chris/0000-0002-1065-7239 NR 17 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 DEC 1 PY 1991 VL 253 IS 3 BP P35 EP P38 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GT569 UT WOS:A1991GT56900022 ER PT J AU SIMPSON, J ROFF, G MORTON, BR LABAS, K DIETACHMAYER, G MCCUMBER, M PENC, R AF SIMPSON, J ROFF, G MORTON, BR LABAS, K DIETACHMAYER, G MCCUMBER, M PENC, R TI A GREAT-SALT-LAKE WATERSPOUT SO MONTHLY WEATHER REVIEW LA English DT Article ID TORNADO-LIKE VORTICES; NUMERICAL SIMULATIONS; CLOUD MODEL; LIFE-CYCLE; VORTEX; THUNDERSTORMS; EVOLUTION; ROTATION; DYNAMICS AB A waterspout funnel and spray ring were observed under a cumulus line over the Great Salt Lake for about 5 min shortly after sunrise on 26 June 1985. Videotaped features strongly suggested that the funnel rotation was anticyclonic. These observations have been used as the basis for a study of the initiation and evolution of waterspouts through a series of numerical experiments at two scales, that of a cloud and a waterspout. The cloud scale has been simulated using an improved Goddard-Schlesinger model with nearby Salt Lake City soundings. The main model improvements have been 1) a parameterized, three-class ice phase and 2) a line initialization in addition to the more common axisymmetric buoyant bubble. Cloud-scale vortex pairs developed for each mode of initiation, but a much stronger, more upright, low-level anticyclonic vortex grew from the line initiation than from the bubble. However, cumulus-scale vortices are common while waterspouts are rare, and the real test of a model is whether a waterspout can develop in the limited cumulus lifetime. The 600-m horizontal grid of the cloud model cannot resolve waterspouts, and a modified Monash high-resolution axisymmetric vortex model with vertical domain and small section has been "embedded" at selected positions and initiated at selected times in the computed flow field of the cloud. Many experiments have been carried out with the vortex model. In the most important series, the boundary conditions were changed with the fields of the model cumulus as it evolved, and the time at which the vortex was started was varied through the lifetime of the parent cloud. Results showed that for each mode of cloud initiation, the vortex that started at the anticyclonic center grew faster than those started at other centers. This result fits with the observed anticyclonic rotation of the waterspout, strongly suggesting that the cloud vorticity was important in its initiation. The greatest azimuthal speed for the bubble-initiated cloud was 11 m s-1 when the vortex model was started at 28 min cloud time with time-varying boundary conditions, whereas it was 21 m s-1 when started at 12 min in the line-initiated cloud. Speeds were comparable when the inner domain moved with the anticyclonic cloud center. These speeds are close to the spray-ring threshold azimuthal velocity of roughly 22 m s-1 estimated by Golden from photographs. Together, these model results support the hypothesis that, at least in some circumstances, cloud processes alone can produce waterspouts in the absence of external vorticity sources such as surface convergence lines or other shear features. C1 MONASH UNIV,CTR DYNAM METEOROL,CLAYTON,VIC 3168,AUSTRALIA. NOAA,US WEATHER SERV OFF,SALT LAKE CITY,UT. BUR METEOROL,RES CTR,MELBOURNE,AUSTRALIA. RES DATA SYST CORP,LANHAM,MD. RP SIMPSON, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 912,GREENBELT,MD 20771, USA. NR 32 TC 10 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD DEC PY 1991 VL 119 IS 12 BP 2741 EP 2770 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY090 UT WOS:A1991GY09000001 ER PT J AU CHEN, C AF CHEN, C TI A NESTED GRID, NONHYDROSTATIC, ELASTIC MODEL USING A TERRAIN-FOLLOWING COORDINATE TRANSFORMATION - THE RADIATIVE-NESTING BOUNDARY-CONDITIONS SO MONTHLY WEATHER REVIEW LA English DT Article ID SENSITIVITY EXPERIMENTS; NUMERICAL SIMULATIONS; TURBULENCE; EQUATIONS; DYNAMICS AB A nested grid, nonhydrostatic, elastic model using a terrain-following coordinate transformation is presented with a unique application of grid-nesting techniques to the time-splitting elastic model. To minimize the wave reflection along the lateral and the upper boundaries of the nested fine-grid model, the conventional nested-grid scheme has been modified so that the fine-grid model has its own "independent" radiative boundary conditions as well as "dependent" nested boundary conditions. This modification is crucial to the success of nested grid simulations. A simulation of the 10-m-high Witch of Agnesi Mountain provides the control to test this new model. The results show that the model produces the same solution as that derived from a simple linear analytic model. The model used in the control case is then double-nested by a fine-grid model that has its primary domain zoomed into the area around the mountain. Using this configuration, one way and two-way grid-nesting sensitivity experiments with various boundary conditions are performed. In order to examine the robustness of the newly developed nesting scheme, the model is further tested by conducting the triple-nesting case, the high-mountain case, and the downslope windstorm case. RP CHEN, C (reprint author), UNIV MARYLAND,NASA,GODDARD SPACE FLIGHT CTR,SPACE RES ASSOC,CODE 912,GREENBELT,MD 20771, USA. NR 25 TC 26 Z9 26 U1 0 U2 0 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 DEC PY 1991 VL 119 IS 12 BP 2852 EP 2869 DI 10.1175/1520-0493(1991)119<2852:ANGNEM>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY090 UT WOS:A1991GY09000007 ER PT J AU JUSEM, JC ATLAS, R AF JUSEM, JC ATLAS, R TI DIAGNOSTIC EVALUATION OF NUMERICAL-MODEL SIMULATIONS USING THE TENDENCY EQUATION SO MONTHLY WEATHER REVIEW LA English DT Article ID PREDICTION; CYCLONE AB A procedure is proposed to expand the diagnostic capabilities of the pressure tendency equation of a primitive equation NWP model by computing the pressure tendency in physical coordinates. The advantage of isolating the density advection as a diagnostic tool to understand pressure changes is shown. By simple thermodynamic arguments it is demonstrated that in areas of synoptic-scale cyclonic development, the vertically integrated density advection is more than sufficient to explain the depletion of mass over a growing depression. Consequently, the joint contribution of the net divergence and vertical motion opposes the pressure fall. This is illustrated for a case of rapid cyclogenesis in southern South America. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 911,GREENBELT,MD 20771. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 29 TC 13 Z9 14 U1 0 U2 0 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 DEC PY 1991 VL 119 IS 12 BP 2936 EP 2955 DI 10.1175/1520-0493(1991)119<2936:DEONMS>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY090 UT WOS:A1991GY09000012 ER PT J AU Marais, DJD AF Marais, David J. Des TI Microbial mats, stromatolites and the rise of oxygen in the Precambrian atmosphere SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Marais, DJD (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 25 TC 0 Z9 0 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD DEC PY 1991 VL 97 IS 1-2 BP 93 EP 96 PG 4 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA V43VU UT WOS:000202963400009 ER PT J AU STRATON, JC DRACHMAN, RJ AF STRATON, JC DRACHMAN, RJ TI FORMATION OF POSITRONIUM IN E+ + H- COLLISIONS SO PHYSICAL REVIEW A LA English DT Article ID TANI TRANSFORMATION; ELECTRON-CAPTURE; HYDROGEN; REPRESENTATION; APPROXIMATION; SCATTERING AB Cross sections for positronium formation by capture from the negative hydrogen ion are given. Orthogonalization corrections to the Coulomb (first-order) Born approximation (CBA) differential and total cross sections are calculated using approximate H- wave functions of both Lowdin [Phys. Rev. 90, 123 (1953)] and Chandrasekhar [Astrophys. J. 100, 176 (1944)]. The present calculation of the CBA cross sections using the post interaction for Lowdin's wave function (LCBAPS) disagrees with the calculation of Choudhury, Mukherjee, and Sural (CMS) [Phys. Rev. A 33, 2358 (1986)], whereas our results using the prior interaction agree. Thus, where CMS found an order of magnitude post-prior discrepancy in the differential cross sections except at forward angles, and a markedly different shape to the minima, the present post and prior results differ by 1-10% at 100 eV, and the minima have the same shape and occur within one degree of each other. Chandrasekhar's "open-shell" wave function, which is superior to Lowdin's in bound-state problems since it gives a negative binding energy, gives post and prior cross sections that are almost indistinguishable at this energy and are 1/2 to 2/3 as large as the LCBA. Various methods of orthogonalizing the unbound projectile to the possible bound states are considered. It is found that treating the atomic nuclei as if they were isotopic spin projections [Straton and Girardeau, Phys. Rev. A 40, 2991 (1989)] of a single type of "nucleon" gives cross sections that are an improvement over the CBA. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP STRATON, JC (reprint author), KANSAS STATE UNIV AGR & APPL SCI,DEPT PHYS,CARDWELL HALL,MANHATTAN,KS 66506, USA. NR 30 TC 4 Z9 4 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD DEC 1 PY 1991 VL 44 IS 11 BP 7335 EP 7343 DI 10.1103/PhysRevA.44.7335 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GU882 UT WOS:A1991GU88200043 ER PT J AU RICHARDSON, WH YAMAMOTO, Y AF RICHARDSON, WH YAMAMOTO, Y TI QUANTUM MEASUREMENT OF THE PHOTON NUMBER VIA THE JUNCTION VOLTAGE IN A SEMICONDUCTOR-LASER SO PHYSICAL REVIEW A LA English DT Article ID NONDEMOLITION MEASUREMENT; OSCILLATOR; SUPPRESSION; MICROMASER AB The quantum correlation between photon number and junction-voltage fluctuations in a constant-current-driven semiconductor laser is theoretically predicted and experimentally demonstrated. An external electrical circuit has the two functions of pumping to compensate for cavity loss and measuring the photon number. The photon-number noise can be reduced to below the standard quantum limit and even to near that of a number state by referring to the junction-voltage measurements. Phase diffusion incorporates the inherent back action noise of such a measurement process. The number-phase uncertainty principle is conserved between the measurement-induced sub-Poissonian photon-number noise and the Schawlow-Townes phase-diffusion noise. C1 NIPPON TELEGRAPH & TEL PUBL CORP, MUSASHINO ELECT COMMUN LAB, BASIC RES LABS, MUSASHINO, TOKYO 180, JAPAN. RP RICHARDSON, WH (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RI Yamamoto, Yoshihisa/A-2811-2012 NR 30 TC 18 Z9 18 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 EI 1094-1622 J9 PHYS REV A JI Phys. Rev. A PD DEC 1 PY 1991 VL 44 IS 11 BP 7702 EP 7716 DI 10.1103/PhysRevA.44.7702 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GU882 UT WOS:A1991GU88200076 ER PT J AU PRUETT, CD NG, LL ERLEBACHER, G AF PRUETT, CD NG, LL ERLEBACHER, G TI ON THE NONLINEAR STABILITY OF A HIGH-SPEED, AXISYMMETRICAL BOUNDARY-LAYER SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID TRANSITION; INSTABILITY AB The stability of a high-speed, axisymmetric boundary-layer flow is investigated by means of secondary instability theory and direct numerical simulation. Parametric studies based on temporal secondary instability theory identify subharmonic secondary instability as a likely path to transition on a hollow cylinder at Mach 4.5. The theoretical predictions are validated by direct numerical solution of the compressible Navier-Stokes equations. Initial perturbations for the temporal direct numerical simulation consist of an axisymmetric "second-mode" primary disturbance and a subharmonic secondary disturbance comprised of four oblique wave components. At small initial amplitudes of the secondary disturbance, growth rates obtained from the spectrally accurate numerical simulation agree to several significant digits with linear growth rates predicted by secondary instability theory. Qualitative agreement persists to relatively large amplitudes of the secondary disturbance. Moderate transverse curvature is shown to significantly affect the growth rate of axisymmetric "second-mode" disturbances, the likely candidates of primary instability. The influence of curvature on secondary instability is largely indirect, but most probably significant, through modulation of the primary disturbance amplitude. Subharmonic secondary instability is shown to be predominantly inviscid in nature, and to account for peaks in the Reynolds stress components near the critical layer. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. RP PRUETT, CD (reprint author), ANALYT SERV & MAT INC,107 RES DR,HAMPTON,VA 23666, USA. NR 42 TC 7 Z9 7 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD DEC PY 1991 VL 3 IS 12 BP 2910 EP 2926 DI 10.1063/1.857834 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GT358 UT WOS:A1991GT35800009 ER PT J AU MAESTRELLO, L BAYLISS, A KRISHNAN, R AF MAESTRELLO, L BAYLISS, A KRISHNAN, R TI ON THE INTERACTION BETWEEN 1ST-MODE AND 2ND-MODE WAVES IN A SUPERSONIC BOUNDARY-LAYER SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID ACTIVE CONTROL; STABILITY; FLOWS AB Linear stability theory predicts two or more types of unstable disturbances in a sufficiently high-speed boundary layer. These include the first mode, which is similar to the Tollmien-Schlichting waves found in low-speed flows, and the second mode, which does not depend strongly on the viscosity. Generally, the most unstable first mode is three dimensional while the most unstable second mode is two dimensional. The interaction between these two spatially unstable modes are studied by direct solution of the three-dimensional Navier-Stokes equations. It is found that the two-dimensional second mode causes a significant increase in the nonlinearity and in the three-dimensionality of the flow field. The results suggest that this interaction may accelerate transition for flows where the second mode has a significant growth rate. C1 NORTHWESTERN UNIV,ROBERT R MCCORMICK SCH ENGN & APPL SCI,DEPT ENGN SCI & APPL MATH,EVANSTON,IL 60208. VIGYAN RES ASSOCIATES INC,HAMPTON,VA 23665. NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. RP MAESTRELLO, L (reprint author), NASA,LANGLEY RES CTR,STRUCT ACOUST BRANCH,HAMPTON,VA 23665, USA. RI Bayliss, Alvin/B-7337-2009 NR 18 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD DEC PY 1991 VL 3 IS 12 BP 3014 EP 3020 DI 10.1063/1.857845 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GT358 UT WOS:A1991GT35800020 ER PT J AU HAMILL, P TOON, OB AF HAMILL, P TOON, OB TI POLAR STRATOSPHERIC CLOUDS AND THE OZONE HOLE SO PHYSICS TODAY LA English DT Article ID NITRIC-ACID TRIHYDRATE; ANTARCTIC OZONE; CONDENSATION NUCLEI; CHLORINE; AEROSOL; DEPLETION; NITRATE C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HAMILL, P (reprint author), SAN JOSE STATE UNIV,PHYS,SAN JOSE,CA 95192, USA. NR 26 TC 53 Z9 53 U1 1 U2 3 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 DEC PY 1991 VL 44 IS 12 BP 34 EP 42 DI 10.1063/1.881277 PG 9 WC Physics, Multidisciplinary SC Physics GA GV836 UT WOS:A1991GV83600006 ER PT J AU BAKER, DN CHIN, G PFAFF, RF AF BAKER, DN CHIN, G PFAFF, RF TI NASA SMALL EXPLORER PROGRAM SO PHYSICS TODAY LA English DT Article RP BAKER, DN (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,SMALL EXPLORER PROGRAM,GREENBELT,MD 20771, USA. RI Chin, Gordon/E-1520-2012; Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 8 TC 4 Z9 4 U1 0 U2 3 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 DEC PY 1991 VL 44 IS 12 BP 44 EP 51 DI 10.1063/1.881278 PG 8 WC Physics, Multidisciplinary SC Physics GA GV836 UT WOS:A1991GV83600007 ER PT J AU MITCHELL, BG BRODY, EA YEH, EN MCCLAIN, C COMISO, J MAYNARD, NG AF MITCHELL, BG BRODY, EA YEH, EN MCCLAIN, C COMISO, J MAYNARD, NG TI MERIDIONAL ZONATION OF THE BARENTS SEA ECOSYSTEM INFERRED FROM SATELLITE REMOTE-SENSING AND INSITU BIOOPTICAL OBSERVATIONS SO POLAR RESEARCH LA English DT Article; Proceedings Paper CT PRO MARE SYMP ON POLAR MARINE ECOLOGY CY MAY 12-16, 1990 CL TRONDHEIM, NORWAY SP NORWEGIAN FISHERIES RES COUNCIL, NORWEGIAN RES COUNCIL SCI & HUMANITIES, MINIST ENVIRONM NORWAY, NORSK HYDRO, NORSKE SHELL AB The Barents Sea is a productive, shallow, high-latitude marine ecosystem with complex hydrographic conditions. Zonal hydrographic bands defined by a coastal current, North Atlantic Water, the Polar Front, and thc seasonally variable marginal ice edge zone create a meridional zonation of thc ecosystem during the spring-summer transition. The features reveal themselves in satellite imagery and by high-resolution (vertical and horizontal) physical-optical-biological sampling. Surprisingly, the long-term (7-year) mean of Coastal Zone Color Scanner (CZCS) imagery reveals the Barents Sea as an anomalous "blue-water" regime at high latitudes that are otherwise dominated by satellite-observed -surface blooms. A combination of satellite imagery and in situ bio-optical analyses indicate that,this pattern is caused by strong stratification in summer with surface nutrient depletion. Thc onset of stratification of the entire region is linked to the extent of thc winter ice edge: cold years with extensive sea ice apparently stratify early due to ice melt; warm years stratify later, perhaps due to weaker thermal stratification of the Atlantic waters (e.g. Skjoldal et al. 1987). The apparent "low chlorophyll" indicated by the CZCS 7-year mean is partly due to sampling error whereby the mean is dominated by images taken later in the summer. In fact, massive blooms of subsurface phytoplankton embedded in the pycnocline persist throughout the summer and maintain substantial rates of primary production. Further. these subsurface blooms that are not observed by satellite are responsible for dramatic gradients in the beam (c(t)) and spectral diffuse (k) attenuation coefficients. The Barents Sea exemplifies the need to couple satellite observations with spatially and temporally resolved biogeographic ecosystem models in order to estimate the integrated water column primary production, mass flux or spectral light attenuation coefficients. RP MITCHELL, BG (reprint author), NASA,HEADQUARTERS CODE SEP,WASHINGTON,DC 20546, USA. NR 0 TC 19 Z9 20 U1 1 U2 6 PU NORWEGIAN POLAR INST PI OSLO PA POSTBOKS 5072 MAJORSTUA, 1330 OSLO, NORWAY SN 0800-0395 J9 POLAR RES JI Polar Res. PD DEC PY 1991 VL 10 IS 1 BP 147 EP 162 DI 10.1111/j.1751-8369.1991.tb00641.x PG 16 WC Ecology; Geosciences, Multidisciplinary; Oceanography SC Environmental Sciences & Ecology; Geology; Oceanography GA HX559 UT WOS:A1991HX55900013 ER PT J AU BARNES, CM AF BARNES, CM TI AN HISTORICAL-PERSPECTIVE ON THE APPLICATIONS OF REMOTE-SENSING TO PUBLIC-HEALTH SO PREVENTIVE VETERINARY MEDICINE LA English DT Article AB This brief paper reviews some basic results of almost 100 scientific papers produced in the 1970-1976 time period by the staff and contractors of the Health Applications Office, Johnson Space Center, Houston, TX. These papers were primarily concerned with the use of sensor data collected from satellites and aircraft for environmental analysis, and ultimately for application to human and animal health. Comment is made on early problem solving, instrumentation development, politics and criticisms of early research efforts, as well as successes and dismal failures which occurred. Philosophical references are made to the sizeable number of problems which still exist in the health field and which might be amenable to solution by the judicious use of remote sensing. RP BARNES, CM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,LIFE SCI DIRECTORATE,HLTH APPLICAT OFF,HOUSTON,TX 77058, USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-5877 J9 PREV VET MED JI Prev. Vet. Med. PD DEC PY 1991 VL 11 IS 3-4 BP 163 EP 166 DI 10.1016/S0167-5877(05)80002-9 PG 4 WC Veterinary Sciences SC Veterinary Sciences GA GW988 UT WOS:A1991GW98800002 ER PT J AU ROBERTS, D RODRIGUEZ, M REJMANKOVA, E POPE, K SAVAGE, H RODRIGUEZRAMIREZ, A WOOD, B SALUTE, J LEGTERS, L AF ROBERTS, D RODRIGUEZ, M REJMANKOVA, E POPE, K SAVAGE, H RODRIGUEZRAMIREZ, A WOOD, B SALUTE, J LEGTERS, L TI OVERVIEW OF FIELD STUDIES FOR THE APPLICATION OF REMOTE-SENSING TO THE STUDY OF MALARIA TRANSMISSION IN TAPACHULA, MEXICO SO PREVENTIVE VETERINARY MEDICINE LA English DT Article AB A National Aeronautics and Space Administration (NASA) sponsored project to use remote sensing technology in a predictive model of vector population dynamics and malaria transmission potential for the coastal plain of Chiapas, Mexico, is described. Included are the results of recent studies to characterize vector habitats and an assessment of the kinds of information that will be required for developing the predictive model within a geographic information system. C1 CTR INVEST PALUDISMO,CHIAPAS,MEXICO. UNIV CALIF DAVIS,DEPT BOT,DAVIS,CA 95616. TGS TECHNOL INC,NASA AMES RES CTR,MOFFETT FIELD,CA 94035. STANFORD UNIV,DEPT ALLIED EARTH SCI,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP ROBERTS, D (reprint author), UNIFORMED SERV UNIV HLTH SCI,DEPT PREVENT MED BIOMETR,4301 JONES BRIDGE RD,BETHESDA,MD 20814, USA. NR 9 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-5877 J9 PREV VET MED JI Prev. Vet. Med. PD DEC PY 1991 VL 11 IS 3-4 BP 269 EP 275 DI 10.1016/S0167-5877(05)80013-3 PG 7 WC Veterinary Sciences SC Veterinary Sciences GA GW988 UT WOS:A1991GW98800013 ER PT J AU WOOD, B WASHINO, R BECK, L HIBBARD, K PITCAIRN, M ROBERTS, D REJMANKOVA, E PARIS, J HACKER, C SALUTE, J SEBESTA, P LEGTERS, L AF WOOD, B WASHINO, R BECK, L HIBBARD, K PITCAIRN, M ROBERTS, D REJMANKOVA, E PARIS, J HACKER, C SALUTE, J SEBESTA, P LEGTERS, L TI DISTINGUISHING HIGH AND LOW ANOPHELINE-PRODUCING RICE FIELDS USING REMOTE-SENSING AND GIS TECHNOLOGIES SO PREVENTIVE VETERINARY MEDICINE LA English DT Article ID CLASSIFICATION AB Worldwide, 140 million ha are devoted to rice cultivation, mostly in developing countries of the tropics and subtropics where malaria still constitutes a serious human health problem. Because rice fields are flood-irrigated on a semi-permanent basis during each growing season, they provide an ideal breeding habitat for a number of potential mosquito vectors of malaria. One of these vectors, Anopheles freeborni, is distributed throughout nearly 240 000 ha of irrigated rice in northern and central California, and may serve as a model for the study of rice field mosquito population dynamics using spectral and spatial information. Analysis of field data revealed that rice fields with rapid early season vegetation canopy development, located near livestock pastures (i.e. bloodmeal sources), had greater mosquito larval populations than fields with more slowly developing vegetation canopies located further from pastures. Remote sensing reflectance measurements of early season rice canopy development and geographic information system (GIS) measurements of distance to livestock pasture were combined to distinguish between high and low mosquito-producing rice fields. These distinctions were made with 90% accuracy nearly 2 months before anopheline larval populations peaked. C1 UNIV CALIF DAVIS,DEPT ENTOMOL,DAVIS,CA 95616. UNIFORMED SERV UNIV HLTH SCI,BETHESDA,MD 20814. CALIF STATE UNIV FRESNO,DEPT GEOG,FRESNO,CA 93740. UNIV TEXAS,HLTH SCI CTR,HOUSTON,TX 77225. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WOOD, B (reprint author), TGS TECHNOL INC,NASA AMES RES CTR,MS 2424,MOFFETT FIELD,CA 94035, USA. NR 18 TC 40 Z9 45 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-5877 J9 PREV VET MED JI Prev. Vet. Med. PD DEC PY 1991 VL 11 IS 3-4 BP 277 EP 288 DI 10.1016/S0167-5877(05)80014-5 PG 12 WC Veterinary Sciences SC Veterinary Sciences GA GW988 UT WOS:A1991GW98800014 ER PT J AU LINTHICUM, KJ BAILEY, CL TUCKER, CJ ANGLEBERGER, DR CANNON, T LOGAN, TM GIBBS, PH NICKESON, J AF LINTHICUM, KJ BAILEY, CL TUCKER, CJ ANGLEBERGER, DR CANNON, T LOGAN, TM GIBBS, PH NICKESON, J TI TOWARDS REAL-TIME PREDICTION OF RIFT-VALLEY FEVER EPIDEMICS IN AFRICA SO PREVENTIVE VETERINARY MEDICINE LA English DT Article ID KENYA; HABITATS AB Outbreaks of Rift Valley fever (RVF) virus in Africa are characterized by distinct spatial and temporal patterns that are directly related to specific environmental parameters associated with mosquito vectors that function in the maintenance (endemic) and transmission (epizootic) cycles of the virus. National Oceanic and Atmospheric Administration (NOAA) satellites with limited resolution (1 km) can indirectly measure rainfall inexpensively over subcontinental or continental areas at a high temporal frequency, and identify regions with a high potential for viral activity. Within regions of likely viral activity, mosquito vector-breeding habitats (dambos) are identified and mapped with archived, high-quality, cloud-free, higher resolution data from LANDSAT (thematic mapper resolution 30 m) and SPOT (multispectral resolution 20 m) satellites. Active sensors, like airborne synthetic aperture radar systems (range resolution 1.6 m), are capable of detecting flooded habitats' even through cloud cover. By identifying flooded habitats within regions with a high likelihood of RVF activity, the potential source foci of an outbreak may be detected close to real-time and control efforts implemented prior to the start of a RVF epidemic/epizootic. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP LINTHICUM, KJ (reprint author), USA,MED RES INST INFECT DIS,DIV VIROL,DEPT ARBOVIRAL ENTOMOL,FT DETRICK,FREDERICK,MD 21701, USA. NR 12 TC 21 Z9 22 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-5877 J9 PREV VET MED JI Prev. Vet. Med. PD DEC PY 1991 VL 11 IS 3-4 BP 325 EP 334 DI 10.1016/S0167-5877(05)80019-4 PG 10 WC Veterinary Sciences SC Veterinary Sciences GA GW988 UT WOS:A1991GW98800019 ER PT J AU KINNEY, AL MARAN, SP AF KINNEY, AL MARAN, SP TI THE 1ST YEAR OF OBSERVATIONS WITH THE HUBBLE SPACE TELESCOPE SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE ACTIVE GALACTIC NUCLEI; ELLIPTIC GALAXIES, NUCLEI; GLOBULAR CLUSTERS; INTERGALACTIC MEDIUM; JETS; NEBULAE; STELLAR ATMOSPHERES ID GLOBULAR-CLUSTER NGC-5466; ELLIPTICAL GALAXIES; ACTIVE GALAXIES; BLUE STRAGGLER; SPECTROPOLARIMETRY; NGC-1068; MERGERS AB The Hubble Space Telescope has gathered unique information that supports many very significant scientific investigations during its early orbital operations, despite the limitations imposed by an unexpected spherical aberration in the primary mirror. These early results, gathered primarily with the HST cameras and spectrographs, are reviewed, with emphasis on extragalactic, stellar, and nebular astronomy. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP KINNEY, AL (reprint author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA. NR 78 TC 3 Z9 3 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 DEC PY 1991 VL 103 IS 670 BP 1237 EP 1249 DI 10.1086/132943 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GX014 UT WOS:A1991GX01400001 ER PT J AU KENNELLY, EJ WALKER, GAH HUBENY, I AF KENNELLY, EJ WALKER, GAH HUBENY, I TI A NONRADIAL PULSATION MODEL FOR THE RAPIDLY ROTATING DELTA-SCUTI STAR KAPPA-2 BOOTIS SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE DELTA-SCUTI STARS; NONRADIAL PULSATIONS ID LINE-PROFILE VARIATIONS; NON-RADIAL OSCILLATIONS; ZETA-OPHIUCHI AB A 2.5-hour time series of high-resolution CFHT spectra of the rapidly rotating delta-Scuti star kappa-2 Boo exhibits a progression of subfeatures moving from blue to red through the absorption lines. We can reproduce these and other variable features with a geometrical model which imposes sectorial nonradial pulsations (NRPs) on the surface of the star. Synthetic spectra generated with the appropriate T(eff) and log g are used as input. The entire wavelength region covered by the observations can be reproduced and the effects of line blending are included explicitly. Identification of low-degree modes is guided by radial-velocity variations and the known photometric variations. We find that the data can be reproduced by the combination of a high-degree l congruent-to 12 mode with P(osc) congruent-to 0.071 day, and a low-degree mode, l congruent-to 0-2 with P(osc) congruent-to 0.071-0.079 day. The projected rotational velocity (upsilon-sin i = 115 +/- 5 km s-1) was determined by fitting synthetic line profiles to the observed spectra. By including in our treatment the limit to possible resolution of the stellar surface set by the intrinsic linewidth and upsilon-sin i, we estimate the velocity amplitude of the high-degree oscillations to be approximately 3.5 km s-1. We find that the ratio of the horizontal and radial pulsation amplitudes is small (k approximately 0.02) and consistent with p-mode oscillations. Comparisons are made with models invoking starspots, and we find that it is impossible to fit the observations of kappa-2 Boo by a starspot model without assuming unrealistic values of radius or equatorial velocity. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. RP KENNELLY, EJ (reprint author), UNIV BRITISH COLUMBIA,DEPT GEOPHYS & ASTRON,VANCOUVER V6T 1Z4,BC,CANADA. NR 28 TC 15 Z9 15 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 DEC PY 1991 VL 103 IS 670 BP 1250 EP 1257 DI 10.1086/132944 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GX014 UT WOS:A1991GX01400002 ER PT J AU OU, YR SRITHARAN, SS AF OU, YR SRITHARAN, SS TI ANALYSIS OF REGULARIZED NAVIER-STOKES EQUATIONS .1. SO QUARTERLY OF APPLIED MATHEMATICS LA English DT Article ID SUITABLE WEAK SOLUTIONS AB A particular form of regularization of the Navier-Stokes equations is analyzed. Global existence and uniqueness is established for two classes of generalized solutions. It is shown that the solution of this regularized system converges to the solution of the conventional Navier-Stokes equations for low Reynolds numbers. Other results obtained are the existence theorem for periodic solution and the squeezing property of solutions. C1 UNIV SO CALIF,LOS ANGELES,CA 90089. RP OU, YR (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 42 TC 11 Z9 11 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0033-569X J9 Q APPL MATH JI Q. Appl. Math. PD DEC PY 1991 VL 49 IS 4 BP 651 EP 685 PG 35 WC Mathematics, Applied SC Mathematics GA GQ659 UT WOS:A1991GQ65900005 ER PT J AU OU, YR SRITHARAN, SS AF OU, YR SRITHARAN, SS TI ANALYSIS OF REGULARIZED NAVIER-STOKES EQUATIONS .2. SO QUARTERLY OF APPLIED MATHEMATICS LA English DT Article AB A particular form of regularization of the Navier-Stokes equations have been analyzed. As a continuation of the previous work, we study in this paper the structure of the attractors characterizing the solutions. Local as well as global invariant manifolds have been found. Regularity properties of these manifolds are analyzed. C1 UNIV SO CALIF,LOS ANGELES,CA 90089. RP OU, YR (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 25 TC 11 Z9 11 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0033-569X J9 Q APPL MATH JI Q. Appl. Math. PD DEC PY 1991 VL 49 IS 4 BP 687 EP 728 PG 42 WC Mathematics, Applied SC Mathematics GA GQ659 UT WOS:A1991GQ65900006 ER PT J AU HERGENROTHER, PM AF HERGENROTHER, PM TI NEW DEVELOPMENTS IN THERMALLY STABLE POLYMERS SO RECUEIL DES TRAVAUX CHIMIQUES DES PAYS-BAS-JOURNAL OF THE ROYAL NETHERLANDS CHEMICAL SOCIETY LA English DT Article DE POLYIMIDES; POLY(ARYLENE ETHERS); POLYQUINOXALONES; BENZOCYCLOBUTENES; HIGH-PERFORMANCE POLYMERS ID DIELS-ALDER POLYMERIZATION; ETHER CONNECTING GROUPS; POLYIMIDES; BISMALEIMIDES; CARBONYL AB Advances in high-temperature polymers since 1985 are discussed with the emphasis on the chemistry. High-temperature polymers refer to materials that exhibit glass-transition temperatures > 200-degrees-C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties. RP HERGENROTHER, PM (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 76 TC 8 Z9 8 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-0513 J9 RECL TRAV CHIM PAY B JI Recl. Trav. Chim. Pays-Bas-J. Roy. Neth. Chem. Soc. PD DEC PY 1991 VL 110 IS 12 BP 481 EP 491 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA GZ629 UT WOS:A1991GZ62900002 ER PT J AU HALL, DK STURM, M BENSON, CS CHANG, ATC FOSTER, JL GARBEIL, H CHACHO, E AF HALL, DK STURM, M BENSON, CS CHANG, ATC FOSTER, JL GARBEIL, H CHACHO, E TI PASSIVE MICROWAVE REMOTE AND INSITU MEASUREMENTS OF ARCTIC AND SUB-ARCTIC SNOW COVERS IN ALASKA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID WATER EQUIVALENT; SATELLITE DATA; SMMR DATA; RADIOMETER; DEPTH AB Between 11 and 19 March 1988, airborne and satellite passive microwave measurements were acquired simultaneously with ground measurements of depth, density and stratigraphy of the snow in central and northern Alaska. Five aircraft flights were flown along a north-south transect between about 147-degrees-W and 152-degrees-W, and extending from about 63-degrees-N (south of Fairbanks, Alaska) to the Arctic Ocean coastline, with an Aircraft Multichannel Microwave Radiometer (AMMR) on-board operating at 92 GHz, 37 GHz, 21 GHz, and 18 GHz. Passive microwave data from the satellite-borne Special Sensor Microwave Imager (SSMI), operating at 85.5 GHz, 37 GHz, 21 GHz, 18 GHz, and 10 GHz, were obtained concurrently. A good correspondence in brightness temperature (T(B)) trends between the aircraft and satellite data was found. However, an expected inverse correlation between depth hoar thickness and T(B) was not found to be strong. A persistent T(B) minimum in both the aircraft and the satellite data was detected along the northern foothills of the Brooks Range. In an area located at about 68-degrees-50'N, 149-degrees-20'W, the T(B) as recorded from the aircraft microwave sensor dropped by 55 K Satellite microwave measurements showed a T(B) decrease of up to 45 K at approximately the same location. Snow pit measurements did not reveal notable differences in snow characteristics or depth in this location. examination of passive microwave satellite data from 1978 to 1987 revealed that similar low late-winter T(B) values were found in approximately the same locations as those observed in March 1988. According to the satellite data, the zone of low T(B) develops as the snow deepens, and reaches the lowest values in March or April each year. The cause of this T(B) minimum is unknown but thought to be related to snow stratigraphy. The observed difficulty in relating the ground measurements to data collected using aircraft and satellite passive microwave sensors is attributed to the fact that the snow depth and character are highly variable in central and northern Alaska. This variability is exemplified in the field measurements as well as in the passive microwave measurements. C1 COLD REG RES & ENGN LAB,FAIRBANKS,AK. UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99701. UNIV HAWAII,HAWAII INST GEOPHYS,DIV PLANETARY GEOSCI,HONOLULU,HI 96822. RP HALL, DK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,CODE 974,GREENBELT,MD 20771, USA. RI Hall, Dorothy/D-5562-2012 NR 46 TC 46 Z9 53 U1 1 U2 3 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 DEC PY 1991 VL 38 IS 3 BP 161 EP 172 DI 10.1016/0034-4257(91)90086-L PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA GY484 UT WOS:A1991GY48400001 ER PT J AU WOODGATE, BE AF WOODGATE, BE TI A FLAT ARRAY LARGE TELESCOPE CONCEPT FOR USE ON THE MOON, EARTH, AND IN SPACE SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB An astronomical optical telescope concept is described which can provide very large collecting areas, of order 1000 m2. This is an order of magnitude larger than the new generation of telescopes now being designed and built. Multiple gimballed flat mirrors direct the beams from a celestial source into a single telescope of the same aperture as each flat mirror. Multiple images of the same source are formed at the telescope focal plane. A beam combiner collects these images and superimposes them into a single image, onto a detector or spectrograph aperture. This telescope could be used on the earth, the moon, or in space. RP WOODGATE, BE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Woodgate, Bruce/D-2970-2012 NR 8 TC 0 Z9 0 U1 0 U2 0 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 DEC PY 1991 VL 62 IS 12 BP 2931 EP 2935 DI 10.1063/1.1142521 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA GV901 UT WOS:A1991GV90100012 ER PT J AU DHADWAL, HS ANSARI, RR MEYER, WV AF DHADWAL, HS ANSARI, RR MEYER, WV TI A FIBEROPTIC PROBE FOR PARTICLE SIZING IN CONCENTRATED SUSPENSIONS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID DYNAMIC LIGHT-SCATTERING; CROSS-CORRELATION; SPECTROSCOPY; DISPERSIONS AB A fiber-optic probe employing two monomode optical fibers, one for transmitting a Gaussian laser beam to the scattering volume and the second, positioned at some backscatter angle, for receiving the scattered light is described. Performance and suitability of the system for a process control environment is assessed by studying a suspension of polystyrene latex particles over a wide range of sizes and concentrations. The results show that the probe is ideal for a process control environment in industrial and laboratory applications. Particle size is recovered, without any additional corrections for multiple light scattering, in concentrations containing up to 10% solids of 39-nm polystyrene latex spheres. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP DHADWAL, HS (reprint author), SUNY STONY BROOK,DEPT ELECT ENGN,STONY BROOK,NY 11794, USA. NR 23 TC 40 Z9 41 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD DEC PY 1991 VL 62 IS 12 BP 2963 EP 2968 DI 10.1063/1.1142190 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA GV901 UT WOS:A1991GV90100020 ER PT J AU PORR, WC REYNOLDS, A LENG, Y GANGLOFF, RP AF PORR, WC REYNOLDS, A LENG, Y GANGLOFF, RP TI ELEVATED-TEMPERATURE CRACKING OF RSP ALUMINUM-ALLOY 8009 - CHARACTERIZATION OF THE ENVIRONMENTAL INFLUENCE SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID AL-ZN-MG; WATER-VAPOR; STRAIN RATE; FATIGUE C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP PORR, WC (reprint author), UNIV VIRGINIA,DEPT MAT SCI & ENGN,CHARLOTTESVILLE,VA 22903, USA. RI Leng, Yang/B-3187-2010; Reynolds, Anthony/F-2585-2010 NR 18 TC 10 Z9 10 U1 0 U2 1 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 DEC PY 1991 VL 25 IS 12 BP 2627 EP 2632 DI 10.1016/0956-716X(91)90129-O PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GU420 UT WOS:A1991GU42000001 ER PT J AU GABB, TP GAYDA, J LERCH, BA HALFORD, GR AF GABB, TP GAYDA, J LERCH, BA HALFORD, GR TI THE EFFECT OF MATRIX MECHANICAL-PROPERTIES ON [0]8 UNIDIRECTIONAL SIC/TI COMPOSITE FATIGUE RESISTANCE SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article RP GABB, TP (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 7 TC 25 Z9 25 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 DEC PY 1991 VL 25 IS 12 BP 2879 EP 2884 DI 10.1016/0956-716X(91)90173-X PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GU420 UT WOS:A1991GU42000045 ER PT J AU EBINGER, CJ KARNER, GD WEISSEL, JK AF EBINGER, CJ KARNER, GD WEISSEL, JK TI MECHANICAL STRENGTH OF EXTENDED CONTINENTAL LITHOSPHERE - CONSTRAINTS FROM THE WESTERN RIFT SYSTEM, EAST-AFRICA SO TECTONICS LA English DT Article ID LAKE TANGANYIKA; ISOSTATIC COMPENSATION; SEDIMENTARY BASINS; SIMPLE SHEAR; UPPER-MANTLE; NORTH-SEA; EVOLUTION; EXTENSION; MODEL; KENYA AB Although regional isostasy generally is associated with continental lithospheric compression and foreland basin formation, local isostatic compensation commonly is assumed in models of extensional basin formation. The assumption of negligible lithospheric strength during rifting often is justified on the basis of: (1) high heat flow and temperatures produced by elevating the lithosphere-asthenosphere boundary and (2) fracturing of the crust and lithosphere by normal faults. By modeling the development of rift basins within the Western rift system of East Africa and their associated free air gravity anomalies, we assess the role of basin-producing normal faults in modifying the flexural strength of extended lithosphere. Heat flow and seismicity data from the East African plateau region indicate that the Western rift system located on the western side of the plateau developed in old, cold continental lithosphere. These relatively narrow (40-70 km wide), but deep, basins are bounded along one side by high-angle border faults that penetrate to lower crustal levels, as indicated by seismicity data. Along the length of the Western rift system, depth to pre-rift basement and rift flank topography vary between basins from 1 to 8 km and from 1 to 2 km respectively, with deeper basins generally correlating with higher flanks. Comparison of model predictions with topography and free air gravity profiles reveals that the basin depth and the flank height in the majority of the Western rift basins studied can be explained simply by small heaves (3-10 km) across the border fault and with significant flexural strength of the lithosphere maintained during extension. Where both observed basin depth and flank height could not be reproduced, basins were located adjacent to eruptive volcanic centers active in Miocene-Recent times. In these areas, basin depth, rift flank elevation, and free air gravity anomaly may be modified by magmatic underplating of the crust. Estimates of effective elastic thickness T(e) obtained from our forward models vary between 17 and 38 km. These T(e) estimates are consistent with previous values obtained through the wavenumber domain correlation of Bouguer gravity and topography data. We find that the lithosphere beneath East Africa maintains significant flexural strength in extension despite localized, but intense, fracturing of the crust by normal faults that penetrate to lower crustal levels. Therefore the assumption of local isostasy (T(e) approximately 0) appears invalid within the youthful Western rift system. C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. RP EBINGER, CJ (reprint author), UNIV LEEDS,DEPT EARTH SCI,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND. NR 82 TC 65 Z9 65 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0278-7407 J9 TECTONICS JI Tectonics PD DEC PY 1991 VL 10 IS 6 BP 1239 EP 1256 DI 10.1029/91TC00579 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GU918 UT WOS:A1991GU91800010 ER PT J AU COLUSSI, AJ SANDER, SP AF COLUSSI, AJ SANDER, SP TI INDUCED CLO VACUUM ULTRAVIOLET FLUORESCENCE SO CHEMICAL PHYSICS LETTERS LA English DT Article ID CIO; STRATOSPHERE; KINETICS; OZONE; NM AB Some vibronic transitions of ClO such as G(upsilon' = 11) <-- X(upsilon" = 10), G(upsilon' = 5) <-- X(upsilon" = 3) and H(upsilon' = 4) <-- X(upsilon" = 2), which promote overtones of X(2-PI-3/2) to bound Rydberg states, are nearly resonant with the 130.6 nm O-atom emission line and possess sizable Franck-Condon factors. On this basis broadband detection of "O atom" fluorescence in experiments involving vibrationally excited ClO(X) is ascribed to the radiative decay of ClO(G, H) rather than to the formation of O atoms; these observations raise the probability of monitoring ClO(X; upsilon = 0) by VUV induced fluorescence. RP COLUSSI, AJ (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Colussi, Agustin/C-6520-2008 NR 21 TC 5 Z9 5 U1 0 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 NOV 29 PY 1991 VL 187 IS 1-2 BP 85 EP 92 DI 10.1016/0009-2614(91)90489-V PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GT724 UT WOS:A1991GT72400015 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI THE BONDING OF MULTIPLE LIGANDS TO MG+ AND AL+ SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; MOLECULAR CALCULATIONS; CLUSTERING REACTIONS; GAS-PHASE; ROW ATOMS; HYDRATION; IONS; CONTRACTION; ENERGIES AB The bonding of one to four water ligands to Mg+ and Al+ is studied. The bonding is very different from that found for multiple ligands bound to Na+ or Cu+. All the waters bind on the same side of the Mg or Al because of the polarization of the 3s orbital away from the ligands. Two benzene and methanol molecules also have a ligand-Mg-ligand angle of less than 180-degrees with the angle determined by ligand-ligand repulsion. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 20 TC 78 Z9 78 U1 0 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 NOV 28 PY 1991 VL 95 IS 24 BP 9694 EP 9698 DI 10.1021/j100177a019 PG 5 WC Chemistry, Physical SC Chemistry GA GR846 UT WOS:A1991GR84600019 ER PT J AU ALLEN, M AF ALLEN, M TI CARBON SUBOXIDE IN HALLEY SO NATURE LA English DT Letter RP ALLEN, M (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 4 Z9 4 U1 2 U2 4 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD NOV 28 PY 1991 VL 354 IS 6351 BP 272 EP 272 DI 10.1038/354272a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GT204 UT WOS:A1991GT20400036 ER PT J AU DOWKER, HF LAFLAMME, R AF DOWKER, HF LAFLAMME, R TI WORMHOLES AND GRAVITONS SO NUCLEAR PHYSICS B LA English DT Article ID QUANTUM-GRAVITY; PERTURBATIONS; UNIVERSE AB We investigate the effect of wormholes on gravitons. We obtain the two-point function for gravitons in asymptotically flat space in the presence of a wormhole. We show that this result can be reproduced in the theory of gravitons in flat space by the first-order contribution to the propagator due to an effective interaction of the form C(mu-nu-rho-sigma)C(mu-nu-rho-sigma). In the linear approximation to pure gravity there are no wormhole-induced corrections to the cosmological constant or to Newton's constant. C1 UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,CAMBRIDGE CB3 9EW,ENGLAND. RP DOWKER, HF (reprint author), FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 31 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD NOV 25 PY 1991 VL 366 IS 1 BP 209 EP 232 DI 10.1016/0550-3213(91)90057-5 PG 24 WC Physics, Particles & Fields SC Physics GA GQ162 UT WOS:A1991GQ16200008 ER PT J AU HOGAN, KB HOFFMAN, JS THOMPSON, AM AF HOGAN, KB HOFFMAN, JS THOMPSON, AM TI METHANE ON THE GREENHOUSE AGENDA SO NATURE LA English DT Editorial Material C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HOGAN, KB (reprint author), US EPA,OFF AIR & RADIAT,WASHINGTON,DC 20460, USA. RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 18 TC 69 Z9 75 U1 0 U2 11 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD NOV 21 PY 1991 VL 354 IS 6350 BP 181 EP 182 DI 10.1038/354181a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GQ948 UT WOS:A1991GQ94800018 ER PT J AU HOVENAC, EA AF HOVENAC, EA TI CALCULATION OF FAR-FIELD SCATTERING FROM NONSPHERICAL PARTICLES USING A GEOMETRICAL-OPTICS APPROACH SO APPLIED OPTICS LA English DT Article DE OPTICAL PARTICLE SIZING; SCATTERING; CALIBRATION; GEOMETRICAL OPTICS ID LIGHT-SCATTERING; SPHEROIDAL PARTICLES AB A numerical method was developed using geometrical optics to predict far-field optical scattering from particles that are symmetric about the optic axis. The diffractive component of scattering is calculated and combined with the reflective and refractive components to give the total scattering pattern. The phase terms of the scattered light are calculated as well Verification of the method was achieved by assuming a spherical particle and comparing the results to Mie scattering theory. Agreement with the Mie theory was excellent in the forward-scattering direction. However, small-amplitude oscillations near the rainbow regions were not observed using the numerical method. Numerical data from spheroidal particles and hemispherical particles are also presented. The use of hemispherical particles as a calibration standard for intensity-type optical particle-sizing instruments is discussed. RP HOVENAC, EA (reprint author), NASA,LEWIS RES CTR,SVERDRUP TECHNOL CORP,CLEVELAND,OH 44135, USA. NR 9 TC 35 Z9 37 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD NOV 20 PY 1991 VL 30 IS 33 BP 4739 EP 4746 PG 8 WC Optics SC Optics GA GX449 UT WOS:A1991GX44900009 PM 20717276 ER PT J AU MIDDLEDITCH, J IMAMURA, JN WOLFF, MT STEIMANCAMERON, TY AF MIDDLEDITCH, J IMAMURA, JN WOLFF, MT STEIMANCAMERON, TY TI HIGH-SPEED MULTICOLOR PHOTOMETRY OF V834 CENTAURUS SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, BINARIES; STARS, DWARF NOVAE; STARS, INDIVIDUAL (V834 CEN); STARS, VARIABLES ID QUASI-PERIODIC OSCILLATIONS; TIME-DEPENDENT ACCRETION; CYCLOTRON EMISSION; WHITE-DWARFS; E1405-451; VARIABILITY; SHOCKS; STARS AB High-speed photometric observations of the AM Her object, V834 Centaurus (= 1E1405-451), during its high state revealed the 0.3-0.9 Hz quasi-periodic oscillations (QPOs) with root-mean-square amplitudes of 3.3% +/- 1.1% and 2.5% +/- 0.8% in the V and R bands, respectively, while the U-band amplitude was consistent with zero on one night but was 2.5% +/- 1.2% on the following night. The QPOs in the B band were always consistent with zero. The data were obtained using the 1 m telescope of the Cerro Tololo Inter-American Observatory on the nights of 1990 June 16-21, when the average V magnitude of V834 Cen was almost-equal-to 15.3, confirming the high-luminosity state. The dominance of the QPOs by V-band emission is in contrast to earlier studies by Larsson which found that the QPOs were dominated by emission in the B and R bands, depending upon the luminosity state of V834 Cen. The QPOs of V834 Cen in all cases, however, have frequencies of 0.3-0.9 Hz. The color of the QPOs could thus be highly variable between luminosity states and may be variable in the U band within the high-luminosity state. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV OREGON,INST THEORET PHYS,EUGENE,OR 97403. UNIV OREGON,DEPT PHYS,EUGENE,OR 97403. UNIV SPACE RES ASSOC,COLUMBIA,MD 21044. NASA,AMES RES CTR,THEORET SCI BRANCH,MOFFETT FIELD,CA 94035. NR 21 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 1991 VL 382 IS 1 BP 315 EP 320 DI 10.1086/170718 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GP641 UT WOS:A1991GP64100032 ER PT J AU WIEDEMANN, GR HINKLE, KH KEADY, JJ DEMING, D JENNINGS, DE AF WIEDEMANN, GR HINKLE, KH KEADY, JJ DEMING, D JENNINGS, DE TI CN AND HCN IN THE INFRARED-SPECTRUM OF IRC+10216 SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SPECTRA; STARS, ABUNDANCES; STARS, CIRCUMSTELLAR SHELLS; STARS, INDIVIDUAL (IRC+10216) ID IRC +10216; CIRCUMSTELLAR ENVELOPE; IRC-+10216; BAND AB The abundance of HCN in the inner circumstellar shell of IRC + 10216 has been remeasured using the 12-mu-m nu-2 band. The 12-mu-m lines are less saturated than HCN 3-mu-m lines previously detected in the spectrum of IRC + 10216. The observed 12-mu-m HCN line is formed in the circumstellar shell from about 4 to 12 R* in accord with a photospheric origin for HCN. The derived HCN abundance in the 4 to 12 R* region is 4 x 10(-5) and the column density is 7 x 10(18) cm-2. The 5-mu-m CN vibration-rotation fundamental band was detected for the first time in an astronomical source. Using four CN lines, the CN column density was determined to be 2.6 x 10(15) cm-2 and the rotational temperature to be 8 +/- 2 K. The peak radial abundance is 1 x 10(-5). The values for the temperature and abundance are in good agreement with microwave results and with the formation of CN from the photolysis of HCN. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,GREENBELT,MD 20771. MAX PLANCK INST EXTRATERRESTR PHYS,GARCHING,GERMANY. NATL OPT ASTRON OBSERV,KITT PEAK NATL OBSERV,TUCSON,AZ 85726. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RI Jennings, Donald/D-7978-2012 NR 30 TC 19 Z9 19 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 NOV 20 PY 1991 VL 382 IS 1 BP 321 EP 326 DI 10.1086/170719 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GP641 UT WOS:A1991GP64100033 ER PT J AU REAMES, DV RICHARDSON, IG BARBIER, LM AF REAMES, DV RICHARDSON, IG BARBIER, LM TI ON THE DIFFERENCES IN ELEMENT ABUNDANCES OF ENERGETIC IONS FROM COROTATING EVENTS AND FROM LARGE SOLAR EVENTS SO ASTROPHYSICAL JOURNAL LA English DT Letter DE COSMIC RAYS, ABUNDANCES; SUN, ABUNDANCES; SUN, CORONA; SUN, SOLAR WIND ID PHOTOSPHERIC ABUNDANCES; PARTICLES; ACCELERATION; ATMOSPHERE; OXYGEN; SHOCKS; NEON; WIND AB We have examined the abundances of energetic ions accelerated from high-speed solar wind streams by shock waves formed at corotating interaction regions (CIRs) where high-speed streams overtake the lower speed solar wind. The observed element abundances appear to represent those of the high-speed solar wind, unmodified by the shock acceleration. These abundances, relative to those in the solar photosphere, are organized by the first ionization potential (FIP) of the ions in a way that is different from the FIP effect commonly used to describe differences between abundances in the solar photosphere and those in the solar corona, solar energetic particles (SEPs), and the low-speed solar wind. In contrast, the FIP effect of the ion abundances in the CIR events is characterized by a smaller amplitude of the difference between high-FIP and low-FIP ions and by elevated abundances of He, C, and S. It is likely that these differences in abundances can be understood in terms of higher temperatures and shorter time scales in the chromospheric fractionation region of coronal holes. Similar processes could also cause the enhanced C/O ratio and the strong suppression of He in the Galactic cosmic-ray sources. C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. RP REAMES, DV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 661,GREENBELT,MD 20771, USA. NR 27 TC 43 Z9 43 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 1991 VL 382 IS 1 BP L43 EP L46 DI 10.1086/186209 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GP642 UT WOS:A1991GP64200010 ER PT J AU MAVRIPLIS, DJ AF MAVRIPLIS, DJ TI TURBULENT-FLOW CALCULATIONS USING UNSTRUCTURED AND ADAPTIVE MESHES SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE TURBULENT; NAVIER-STOKES; UNSTRUCTURED; ADAPTIVE AB A method of efficiently computing turbulent compressible flow over complex two-dimensional configurations is presented. The method makes use of fully unstructured meshes throughout the entire flow field, thus enabling the treatment of arbitrarily complex geometries and the use of adaptive meshing techniques throughout both viscous and inviscid regions of the flow field. Mesh generation is based on a locally mapped Delaunay technique in order to generate unstructured meshes with highly stretched elements in the viscous regions. The flow equations are discretized using a finite element Navier-Stokes solver, and rapid convergence to steady state is achieved using an unstructured multigrid algorithm, Turbulence modelling is performed using an inexpensive algebraic model, implemented for use on unstructured and adaptive meshes. Compressible turbulent flow solutions about multiple-element aerofoil geometries are computed and compared with experimental data. RP MAVRIPLIS, DJ (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,MAIL STOP 132C,HAMPTON,VA 23665, USA. NR 20 TC 20 Z9 20 U1 0 U2 3 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 NOV 20 PY 1991 VL 13 IS 9 BP 1131 EP 1152 DI 10.1002/fld.1650130905 PG 22 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA GQ681 UT WOS:A1991GQ68100004 ER PT J AU GIRDLER, RW AF GIRDLER, RW TI THE CASE FOR OCEAN CRUST BENEATH THE RED-SEA SO TECTONOPHYSICS LA English DT Article ID EVOLUTION; GULF C1 UNIV NEWCASTLE UPON TYNE,DEPT PHYS,NEWCASTLE TYNE NE1 7RU,TYNE & WEAR,ENGLAND. RP GIRDLER, RW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 622,GREENBELT,MD 20771, USA. NR 30 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD NOV 20 PY 1991 VL 198 IS 2-4 BP 275 EP 278 DI 10.1016/0040-1951(91)90155-L PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GZ237 UT WOS:A1991GZ23700009 ER PT J AU FRIEMAN, JA GRADWOHL, BA AF FRIEMAN, JA GRADWOHL, BA TI DARK MATTER AND THE EQUIVALENCE PRINCIPLE SO PHYSICAL REVIEW LETTERS LA English DT Article ID GALACTIC HALOS; COMA CLUSTER; GALAXIES AB If the dark matter in galaxies and clusters is nonbaryonic, it can interact with additional long-range fields that are invisible to experimental tests of the equivalence principle. We discuss the astrophysical and cosmological implications of a long-range force coupled only to the dark matter and find rather tight constraints on its strength. If the force is repulsive (attractive), the masses of galaxy groups and clusters (and the mean density of the Universe inferred from them) have been systematically underestimated (overestimated). Such an interaction also has unusual implications for the growth of large-scale structure. RP FRIEMAN, JA (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 23 TC 49 Z9 49 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 18 PY 1991 VL 67 IS 21 BP 2926 EP 2929 DI 10.1103/PhysRevLett.67.2926 PG 4 WC Physics, Multidisciplinary SC Physics GA GQ408 UT WOS:A1991GQ40800002 ER PT J AU SCHURE, MR WEERATUNGA, SK AF SCHURE, MR WEERATUNGA, SK TI CORIOLIS-INDUCED SECONDARY FLOW IN SEDIMENTATION FIELD-FLOW FRACTIONATION SO ANALYTICAL CHEMISTRY LA English DT Article ID CHANNEL FLOW; CHROMATOGRAPHY; LIMIT; INSTABILITIES; PARTICLES; RETENTION; DUCTS AB In an attempt to examine the effect of smaller channel breadth in sedimentation field-flow fractionation channels, computer simulations of zone profiles are reported which utilize the complete fully developed flow field obtained from Navier-Stokes calculations. The flow field displays Coriolis-induced secondary flow which results when a moving fluid is rotated regardless of the radius of curvature of the channel. By inclusion of secondary flow in the simulation, it is suggested that channel breadths smaller than those used in commercial fractionators will lead to zone leakage; i.e. a small concentration of particles will be found between the void peak and retained peak. Simulation demonstrates that when channel rotation is in the same direction as flow, zone leakage is enhanced compared with the case where flow and rotation are in opposing directions. To reduce zone dilution, which is found to be linear in channel breadth, it is recommended that channel thickness be reduced because of its 3/2 power dependence on the dilution factor. Smaller channel thickness also allows the channel breadth to be reduced because of the reduction in secondary flow. Concentrations of flow in a circular channel are also given to explain why circular channels fall to perform adequately in sedimentation FFF. C1 NASA,AMES RES CTR,NUMER AERODYNAM SIMULAT GRP,MOFFETT FIELD,CA 94035. RP SCHURE, MR (reprint author), ROHM & HAAS CO,COMP APPLICAT RES,727 NORRISTOWN RD,SPRING HOUSE,PA 19477, USA. NR 41 TC 16 Z9 16 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 15 PY 1991 VL 63 IS 22 BP 2614 EP 2626 DI 10.1021/ac00022a015 PG 13 WC Chemistry, Analytical SC Chemistry GA GP581 UT WOS:A1991GP58100015 ER PT J AU JACKSON, HW BARMATZ, M AF JACKSON, HW BARMATZ, M TI MICROWAVE-ABSORPTION BY A LOSSY DIELECTRIC SPHERE IN A RECTANGULAR CAVITY SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB A new theory of absorption of microwave power by a lossy dielectric sphere in a resonant rectangular chamber is developed here. In this treatment, resonant modes of the cavity are resolved into traveling plane-wave fields, and Mie's theory of scattering and absorption of a plane electromagnetic wave by a sphere is utilized. The fields in the cavity containing the sphere are found by superposition of results for the individual scattering problem for each traveling plane wave. Absorbed power is then calculated by evaluating the time-averaged Poynting vector and integrating over the surface of the sphere. Applications of microwave power absorption are discussed, with particular emphasis on processing of materials. Numerical studies based on the newly derived formulas are presented. The results exhibit the manner in which microwave absorption is influenced by a number of different experimentally controllable parameters. The examples considered were chosen with a view toward designing experiments and apparatus for containerless processing of materials in the microgravity environment of space. RP JACKSON, HW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 17 TC 14 Z9 14 U1 3 U2 4 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 NOV 15 PY 1991 VL 70 IS 10 BP 5193 EP 5204 DI 10.1063/1.350227 PN 1 PG 12 WC Physics, Applied SC Physics GA GQ943 UT WOS:A1991GQ94300004 ER PT J AU RUCKMAN, MW HEPP, AF AF RUCKMAN, MW HEPP, AF TI NEAR-EDGE STUDY OF GOLD-SUBSTITUTED YBA2CU3O7-DELTA SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID BA-CU-O; HIGH-TC SUPERCONDUCTORS; VALENCE; YBA2(CU1-XFEX)3O7-DELTA AB The valence of Cu and Au in YBa2Au0.3Cu2.7O7-delta was investigated using x-ray absorption near-edge structure (XANES). X-ray and neutron diffraction studies indicate that Au goes on the Cu(1) site and Cu K-edge XANES shows that this has little effect on the oxidation state of the remaining copper. The Au L3 edge develops a white line feature whose position lies between that of trivalent gold oxide (Au2O3) and monovalent potassium gold cyanide (KAu(CN)2) and whose height relative to the edge step is smaller than in the two reference compounds. The appearance of the Au L3 edge suggests that fewer Au 3d states are involved in forming the Au-O bond in YBa2Au0.3Cu2.7O7-delta than in trivalent gold oxide. C1 NASA,LEWIS RES CTR,DIV POWER TECHNOL,CLEVELAND,OH 44135. RP RUCKMAN, MW (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 26 TC 4 Z9 4 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD NOV 15 PY 1991 VL 70 IS 10 BP 5713 EP 5715 DI 10.1063/1.350166 PN 1 PG 3 WC Physics, Applied SC Physics GA GQ943 UT WOS:A1991GQ94300078 ER PT J AU WALSH, EJ JACKSON, FC HINES, DE PIAZZA, C HEVIZI, LG MCLAUGHLIN, DJ MCINTOSH, RE SWIFT, RN SCOTT, JF YUNGEL, JK FREDERICK, EB AF WALSH, EJ JACKSON, FC HINES, DE PIAZZA, C HEVIZI, LG MCLAUGHLIN, DJ MCINTOSH, RE SWIFT, RN SCOTT, JF YUNGEL, JK FREDERICK, EB TI FREQUENCY-DEPENDENCE OF ELECTROMAGNETIC BIAS IN RADAR ALTIMETER SEA-SURFACE RANGE MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID MSL AB Range measurements made by satellite radar altimeters experience a bias toward the troughs of ocean waves. A series of aircraft flights during February-April 1989 measured this electromagnetic (EM) bias at three radar frequencies and the UV under a variety of wind and wave conditions, and provided the first airborne open-ocean measurements at the 13.6-GHz and 5.3-GHz operating frequencies of the NASA altimeter on the TOPEX/Poseidon satellite. The data suggest that the mean EM bias decreases linearly with increasing radar frequency between 5.3 and 36 GHz, according to the expression: EM bias (% of significant wave height) = (3.0-0.0617 F)(1 +/- 0.5), where F is in gigahertz. EM bias is fairly constant over a mesoscale region on a given day but can fluctuate significantly from one day to another. It shows a strong increase at all radar frequencies with increasing wind speed, although other sea state conditions, such as the wind direction relative to the wave direction, are also factors. C1 EG&G WASHINGTON ANALYT SERV CTR INC,POCOMOKE CITY,MD 21851. UNIV MASSACHUSETTS,DEPT ELECT & COMP ENGN,AMHERST,MA 01003. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 14 TC 26 Z9 26 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-OCEANS JI J. Geophys. Res.-Oceans PD NOV 15 PY 1991 VL 96 IS C11 BP 20571 EP 20583 DI 10.1029/91JC02097 PG 13 WC Oceanography SC Oceanography GA GQ693 UT WOS:A1991GQ69300014 ER PT J AU CARDER, KL HAWES, SK BAKER, KA SMITH, RC STEWARD, RG MITCHELL, BG AF CARDER, KL HAWES, SK BAKER, KA SMITH, RC STEWARD, RG MITCHELL, BG TI REFLECTANCE MODEL FOR QUANTIFYING CHLOROPHYLL-A IN THE PRESENCE OF PRODUCTIVITY DEGRADATION PRODUCTS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DISSOLVED ORGANIC-MATTER; APPARENT OPTICAL-PROPERTIES; SPECTRAL ABSORPTION; NATURAL-WATERS; OCEAN COLOR; PACIFIC-OCEAN; YELLOW SUBSTANCE; COASTAL WATERS; IN-WATER; PHYTOPLANKTON AB Marine colored dissolved organic matter (CDOM) (also gilvin or yellow substance) absorbs light at an exponentially decreasing rate as a function of wavelength. From 410 nm to about 640 nm, particulate phytoplankton degradation products including pheopigments, detritus, and bacteria have absorption curves that are similar in shape to that of CDOM. In coastal areas and areas downstream from upwelling regions, these constituents of seawater often absorb much more light than do living phytoplankton, leading to errors in satellite-derived chlorophyll estimates as high as 133%. Proposed NASA sensors for the 1990s will have spectral channels as low as 412 nm, permitting the development of algorithms that can separate the absorption effects of CDOM and other phytoplankton degradation products from those due to biologically viable pigments. A reflectance model has been developed to estimate chlorophyll a concentrations in the presence of CDOM, pheopigments, detritus, and bacteria. Nomograms and lookup tables have been generated to describe the effects of different mixtures of chlorophyll a and these degradation products on the R(412):R(443) and R(443):R(565) remote-sensing reflectance or irradiance reflectance ratios. These are used to simulate the accuracy of potential ocean color satellite algorithms, assuming that atmospheric effects have been removed. For the California Current upwelling and offshore regions, with chlorophyll a less-than-or-equal-to 1.3 mg m-3, the average error for chlorophyll a retrievals derived from irradiance reflectance data for degradation product-rich areas was reduced from +/- 61% to +/- 23% by application of an algorithm using two reflectance ratios (R(412):R(443) and R(443):R(565)) rather than the commonly used algorithm applying a single reflectance ratio (R(443):R(565)). C1 UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093. NASA,OCEAN PROD PROGRAM,WASHINGTON,DC 20546. UNIV CALIF SANTA BARBARA,CTR REMOTE SENSING & ENVIRONM OPT,SANTA BARBARA,CA 93106. RP CARDER, KL (reprint author), UNIV S FLORIDA,DEPT MARINE SCI,140 7TH AVE S,ST PETERSBURG,FL 33701, USA. NR 79 TC 187 Z9 204 U1 2 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 NOV 15 PY 1991 VL 96 IS C11 BP 20599 EP 20611 DI 10.1029/91JC02117 PG 13 WC Oceanography SC Oceanography GA GQ693 UT WOS:A1991GQ69300016 ER PT J AU BROCK, JC MCCLAIN, CR LUTHER, ME HAY, WW AF BROCK, JC MCCLAIN, CR LUTHER, ME HAY, WW TI THE PHYTOPLANKTON BLOOM IN THE NORTHWESTERN ARABIAN SEA DURING THE SOUTHWEST MONSOON OF 1979 SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID ZONE COLOR SCANNER; WESTERN INDIAN-OCEAN; PIGMENT CONCENTRATIONS; NORTHERN CALIFORNIA; ATLANTIC BIGHT; SUMMER MONSOON; VARIABILITY; MODEL; IMAGERY; STREAM AB The biological variability of the northwestern Arabian Sea during the 1979 southwest monsoon has been investigated by the synthesis of satellite ocean color remote sensing with analysis of in situ hydrographic and meteorological data sets and the results of wind-driven modeling of upper ocean circulation. The phytoplankton bloom in the northwestern Arabian Sea peaked during August-September, extended from the Oman coast to about 65-degrees-E, and lagged the development of open-sea upwelling by at least 1 month. In total, the pigment distributions, hydrographic data, and model results all suggest that the bloom was driven by spatially distinct upward nutrient fluxes to the euphotic zone forced by the physical processes of coastal upwelling and offshore Ekman pumping. Coastal upwelling was evident from May through September, yielded the most extreme concentrations of phytoplankton biomass, and along the Arabian coast was limited to the continental shelf in the promotion of high concentrations of phytoplankton. Upward Ekman pumping to the northwest of the Somali Jet axis stimulated the development of a broad open-sea phytoplankton bloom oceanward of the Oman shelf. Vertical mixing during the 1979 southwest monsoon was apparently not a primary cause of the regional-scale phytoplankton bloom. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV S FLORIDA,DEPT MARINE SCI,ST PETERSBURG,FL 33701. NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771. NR 81 TC 95 Z9 95 U1 2 U2 10 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 NOV 15 PY 1991 VL 96 IS C11 BP 20623 EP 20642 DI 10.1029/91JC01711 PG 20 WC Oceanography SC Oceanography GA GQ693 UT WOS:A1991GQ69300018 ER PT J AU DRINKWATER, MR KWOK, R WINEBRENNER, DP RIGNOT, E AF DRINKWATER, MR KWOK, R WINEBRENNER, DP RIGNOT, E TI MULTIFREQUENCY POLARIMETRIC SYNTHETIC APERTURE RADAR OBSERVATIONS OF SEA ICE SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID PASSIVE MICROWAVE OBSERVATIONS; LABRADOR SEA; SAR IMAGERY; MARGIN DATA; MOTION; SIGNATURES; ZONE; CLASSIFICATION; FREQUENCIES; SUMMER AB The first known fully polarimetric airborne synthetic aperture radar (SAR) data set of sea ice is introduced. Images were acquired in the Beaufort, Bering and Chukchi seas in March 1988, during a campaign for validation of Defense Meteorological Satellite Program Special Sensor Microwave Imager radiometer ice products. Statistics of the magnitude, phase and polarization of complex backscattered signals recorded by the Jet Propulsion Laboratory three-frequency SAR are examined in detail for various scenes with different ice characteristics. The full Stokes matrix information generated from C, L, and P band data characterize the scattering behavior of different ice types. Polarization ratios and phase differences between linear copolarized returns are used for discrimination between particular image features and mechanisms are suggested for the observed polarimetric characteristics. Results indicate that combinations of frequency and polarization enhance current capability to distinguish ice of different properties using single frequency, fixed polarization microwave radar. A specific example is the polarimetric identification of new ice formation which may not be easily distinguished in ERS-1 5.3 GHz, VV polarization SAR data. Such findings are consistent with theoretical model simulations of scattering characteristics of sea ice. Overall, these preliminary results demonstrate that radar polarimetry will likely add a new dimension to our current capability for extracting geophysically important ice variables using radar remote sensing methods. C1 UNIV WASHINGTON,CTR POLAR SCI,APPL PHYS LAB,SEATTLE,WA 98195. RP DRINKWATER, MR (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Drinkwater, Mark/C-2478-2011; Rignot, Eric/A-4560-2014 OI Kwok, Ron/0000-0003-4051-5896; Drinkwater, Mark/0000-0002-9250-3806; Rignot, Eric/0000-0002-3366-0481 NR 46 TC 47 Z9 47 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-OCEANS JI J. Geophys. Res.-Oceans PD NOV 15 PY 1991 VL 96 IS C11 BP 20679 EP 20698 DI 10.1029/91JC01915 PG 20 WC Oceanography SC Oceanography GA GQ693 UT WOS:A1991GQ69300022 ER PT J AU JORDAN, K CLINTON, R JEELANI, S AF JORDAN, K CLINTON, R JEELANI, S TI EVALUATION OF THE INTERFACIAL BOND PROPERTIES BETWEEN CARBON PHENOLIC AND GLASS PHENOLIC COMPOSITES SO JOURNAL OF MATERIALS SCIENCE LA English DT Article AB The effects of moisture and surface finish on the mechanical and physical properties of the interfacial bond between the carbon/phenolic (C/P) and glass/phenolic (G/P) composite materials are presented in this paper. Four flat panel laminates were fabricated using the C/P and G/P materials. Of the four laminates, one panel was fabricated in which the C/P and G/P materials were cured simultaneously. It was identified as the cocure. The remaining laminates were processed with an initial simultaneous cure of the three C/P billets. Two surface finishes, one on each half, were applied to the top surface. Prior to the application and cure of the G/P material to the machined surface of the three C/P panels, each was subjected to specific environmental conditioning. Types of conditioning included: (a) nominal fabrication environment, (b) a prescribed drying cycle, and (c) a total immersion in water at 71-degrees-C. Physical property tests were performed on specimens removed from the C/P materials of each laminate for determination of the specific gravity, residual volatiles and resin content. Comparison of results with Shuttle Solid Rocket Motor (SRM) nozzle material specifications verified that the materials used in fabricating the laminates met acceptance criteria and were representative of SRM nozzle materials. Mechanical property tests were performed at room temperature on specimens removed from the G/P, the C/P and at the interface between the two materials for each laminate. The double-notched shear strength test was used to determine the ultimate interlaminar shear strength. Results indicate no appreciable difference in the C/P material of the four laminates with the exception of the cocure laminate, where a 20% reduction in the strength was observed. The most significant effect occurred in the bondline specimens. The failure mode was shifted from the C/P material to the interface and the ultimate strength was significantly reduced in the wet material. No appreciable variation was noted between the surface finishes in the wet laminate. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. TUSKEGEE UNIV,MAT RES LAB,TUSKEGEE,AL 36088. RP JORDAN, K (reprint author), HUGHES AIRCRAFT CO,TUCSON,AZ 85736, USA. NR 22 TC 2 Z9 2 U1 2 U2 4 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 NOV 15 PY 1991 VL 26 IS 22 BP 6016 EP 6022 DI 10.1007/BF01113877 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA GR018 UT WOS:A1991GR01800006 ER PT J AU BOERS, R AF BOERS, R TI SATURATION POINT REPRESENTATION OF CLOUD-TOP ENTRAINMENT INSTABILITY SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MARINE STRATOCUMULUS CLOUDS; ATMOSPHERIC BOUNDARY-LAYER; LIDAR OBSERVATIONS; PARAMETERIZATION; OCEAN AB Cloud-top entrainment instability was investigated using a mixing line analysis. Mixing time scales are closely related to the actual size of the parcel, so that local instabilities are largely dependent on the scales of mixing near the cloud top. Given a fixed transport velocity, variation over a small range of parcel length scales (parcel mixing velocities) turns an energy-producing mixing process into an energy-consuming mixing process. It is suggested that a single criterion for cloud-top entrainment instability will not be found due to the role of at least three factors operating more or less independently: the stability of the mixing line, the entrainment speed, and the strength of the internal boundary-layer circulation. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BOERS, R (reprint author), CSIRO,DIV ATMOSPHER RES,STN ST,ASPENDALE VICTORIA,PRIVATE BAG NO 1,MORDIALLOC,VIC,AUSTRALIA. NR 21 TC 7 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD NOV 15 PY 1991 VL 48 IS 22 BP 2426 EP 2435 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GY270 UT WOS:A1991GY27000005 ER PT J AU RESSELL, MT AF RESSELL, MT TI LIMITS TO THE RADIATIVE DECAY OF THE AXION SO PHYSICAL REVIEW D LA English DT Article ID STRONG CP PROBLEM; X-RAY-EMISSION; DARK MATTER; SPECTROPHOTOMETRIC STANDARDS; INVISIBLE AXIONS; HADRONIC AXIONS; GALACTIC HALOES; NIGHT-SKY; CLUSTERS; GALAXIES AB An axion with a mass greater than 1 eV should be detectable through its decay into two photons. In this paper I discuss the astrophysical and cosmological limits which define a small window of allowed axion mass above 3 eV. A firm upper bound to the axion's mass of m(a) less-than-or-equal-to 8 eV is derived by considering the effect of decaying axions upon the diffuse extragalactic background radiation and the brightness of the night sky due to axions in the halo of our Galaxy. The intergalactic light of clusters of galaxies is shown to be an ideal place to search for an emission line arising from the radiative decay of axions. An unsuccessful search for this emission line in three clusters of galaxies is then detailed. Limits to the presence of any intracluster line emission are derived with the result that axions with masses between 3 and 8 eV are excluded by the data, effectively closing this window of axion mass, unless a severe cancellation of axionic decay amplitudes occurs. The intracluster flux limits are then used to constrain the amplitude of any such model dependence. C1 FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP RESSELL, MT (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 62 TC 49 Z9 49 U1 2 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 NOV 15 PY 1991 VL 44 IS 10 BP 3001 EP 3020 DI 10.1103/PhysRevD.44.3001 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GT643 UT WOS:A1991GT64300008 ER PT J AU KAMIONKOWSKI, M AF KAMIONKOWSKI, M TI ENERGETIC NEUTRINOS FROM HEAVY-NEUTRALINO ANNIHILATION IN THE SUN SO PHYSICAL REVIEW D LA English DT Article ID COLD-DARK-MATTER; COSMIC-RAY ANTIPROTONS; PHOTINO-DOMINATED UNIVERSE; ASTROPHYSICAL IMPLICATIONS; HIGGS BOSONS; GAMMA-RAYS; SUPERSYMMETRIC MODELS; MASSIVE PARTICLES; STANDARD MODEL; PROBE AB Neutralinos may be captured in the Sun and annihilate therein producing high-energy neutrinos. Present limits on the flux of such neutrinos from underground detectors such as Irvine-Michigan-Brookhaven (IMB) and Kamiokande II may be used to rule out certain supersymmetric dark-matter candidates, while in many other supersymmetric models the rates are large enough that if neutralinos do reside in the galactic halo, observation of a neutrino signal may be possible in the near future. Neutralinos that are either nearly pure Higgsino or a Higgsino-gaugino combination are generally captured in the Sun by a scalar interaction with nuclei in which a virtual lightest Higgs boson is exchanged. If the squark mass is not much greater than the neutralino mass then capture of neutralinos that are primarily gaugino occurs predominantly by spin-dependent scattering off hydrogen in the Sun. Although only neutrinos from annihilation in the Sun are considered here, the neutrino signal from weakly interacting massive particle annihilation in the Earth should be of comparable strength. Detection rates for mixed-state neutralinos are generally higher than those for Higgsinos or gauginos. C1 UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. NR 91 TC 106 Z9 106 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 NOV 15 PY 1991 VL 44 IS 10 BP 3021 EP 3042 DI 10.1103/PhysRevD.44.3021 PG 22 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GT643 UT WOS:A1991GT64300009 ER PT J AU JAIN, RK LANDIS, GA AF JAIN, RK LANDIS, GA TI CALCULATED PERFORMANCE OF P+N INP SOLAR-CELLS WITH IN0.52AL0.48AS WINDOW LAYERS SO APPLIED PHYSICS LETTERS LA English DT Article AB We have calculated the performance of indium phosphide solar cells with lattice matched wide band-gap In0.52Al0.48As window layers using the PC-1D computer code. The conversion efficiency of p + n InP solar cells is improved significantly by the window layer. No improvement is seen for n + p structures. The improvement in InP cell efficiency was studied as a function of In0.52Al0.48As layer thickness. The use of the window layer improves both the open circuit voltage and short circuit current. For a typical In0.52Al0.48As window layer thickness of 20 nm, the cell efficiency improves in excess of 27% to a value of 18.74%. C1 SVERDRUP TECHNOL INC, BROOK PK, OH 44142 USA. RP JAIN, RK (reprint author), NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 11 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 NOV 11 PY 1991 VL 59 IS 20 BP 2555 EP 2557 DI 10.1063/1.105951 PG 3 WC Physics, Applied SC Physics GA GP275 UT WOS:A1991GP27500026 ER PT J AU TULLOS, GL CASSIDY, PE STCLAIR, AK AF TULLOS, GL CASSIDY, PE STCLAIR, AK TI POLYMERS DERIVED FROM HEXAFLUOROACETONE - 12F-POLY(ETHER KETONE) SO MACROMOLECULES LA English DT Article AB The compounds 2,2-bis[4-(4-fluorobenzoyl)phenyl]propane and 2,2-bis[4-(4-fluorobenzoyl)-phenyl]hexafluoropropane were synthesized, and each was polymerized with Bisphenol A or Bisphenol AF (155-degrees-C for 3-6 h in N,N-dimethylacetamide (DMAc)) to give an homologous series of four, thermally stable, aromatic poly(ether ketones) in yields greater than 90%. Incorporation of hexafluoroisopropylidene (6F) and/or isopropylidene (6H) groups in the poly(ether ketone) backbone greatly enhanced the solubility of these polymers (compared to Victrex PEEK) in common organic solvents. Thermal stabilities by TGA for the polymer series ranged from 485 to 553-degrees-C in air at the point of 10% weight loss. Glass transition temperatures (T(g)) ranged from 169 to 180-degrees-C by DSC. The synthesis and characterization of poly(ether ketones) containing 6F and 6H groups in the backbone are reported along with a study of the effect that replacing the 6H group with the 6F group has on the properties of the polymers. C1 SW TEXAS STATE UNIV,DEPT CHEM,SAN MARCOS,TX 78666. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 21 TC 79 Z9 79 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 11 PY 1991 VL 24 IS 23 BP 6059 EP 6064 DI 10.1021/ma00023a002 PG 6 WC Polymer Science SC Polymer Science GA GQ428 UT WOS:A1991GQ42800002 ER PT J AU PESENSON, L ROBERTAZZI, RP BUHRMAN, RA CYPHER, SR HUNT, BD AF PESENSON, L ROBERTAZZI, RP BUHRMAN, RA CYPHER, SR HUNT, BD TI INTERACTING AND SELF-ORGANIZED 2-LEVEL STATES IN TUNNEL BARRIERS SO PHYSICAL REVIEW LETTERS LA English DT Article ID NOISE; JUNCTIONS AB The excess low-frequency 1/f noise and discrete two-level resistance fluctuations (TLFs) were studied in small-area NbN-MgO-NbN tunnel junctions with a high, low-temperature density of active defects. Strong and evolving interactions between large TLFs indicate that these fluctuations result from the self-organization of interacting defect elements. In the low-T tunneling regime, an unusual slowing down of the rates and a decrease in amplitude with increasing T is sometimes observed, indicative of a thermally induced change in the self-organized two-level state. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP PESENSON, L (reprint author), CORNELL UNIV,SCH APPL & ENGN PHYS,ITHACA,NY 14853, USA. NR 11 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD NOV 11 PY 1991 VL 67 IS 20 BP 2866 EP 2869 DI 10.1103/PhysRevLett.67.2866 PG 4 WC Physics, Multidisciplinary SC Physics GA GP277 UT WOS:A1991GP27700031 ER PT J AU KUSUNOSE, M MINESHIGE, S AF KUSUNOSE, M MINESHIGE, S TI PAIR-DENSITY TRANSITIONS IN ACCRETION DISK CORONAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION; BLACK HOLES; RADIATION MECHANISMS ID ELECTRON-POSITRON PAIRS; RELATIVISTIC THERMAL PLASMAS; BLACK-HOLES; CYGNUS X-1; INSTABILITIES; EQUILIBRIA; PHOTONS AB We investigate the thermal and e+e-(-)pair equilibrium structure of two-temperature disk coronae above a cool (T approximately 10(6) K) disk around a black hole of 10 M.. Soft photons are assumed to be amply supplied from the cool disk. We then find two pair thermal equilibrium points for a given proton column density: the low state with very small pair density and the high state dominated by pairs. Both states are thermally unstable, while for perturbations in pair density the high state is unstable and the low state is stable. Two possible scenarios are discussed for the fate of a two-temperature corona. When the proton optical depth, tau-p, is relatively small (e.g., less than 1) and the temperature of input soft photons is low (e.g., T(soft) less-than-or-similar-to 10(6) K), the corona will undergo a limit cycle between the high state and the low state on a time scale of milliseconds. As a consequence of Compton scattering of the soft photons, the emergent spectrum in the high state is rather flat with a big Wien bump at approximately 100 keV, whereas it is composed of a power-law component in the low state. When tau-p is relatively large (e.g., tau-p = 2) or T(soft) greater-than-or-similar-to 2 x 10(6) K, in contrast, the plasma will cool to form a one-temperature corona. The emergent spectrum is then almost a blackbody with energy approximately 1 keV. Some observational consequences are briefly discussed in connection with the high-low spectral transition in Cyg X-1. C1 IBARAKI UNIV,DEPT PHYS,MITO,IBARAKI 310,JAPAN. UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE,ENGLAND. RP KUSUNOSE, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES65,HUNTSVILLE,AL 35812, USA. NR 20 TC 5 Z9 5 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 NOV 10 PY 1991 VL 381 IS 2 BP 490 EP 495 DI 10.1086/170672 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN112 UT WOS:A1991GN11200015 ER PT J AU KORYCANSKY, DG AF KORYCANSKY, DG TI 2-DIMENSIONAL HYDRODYNAMIC CALCULATIONS OF THE NONLINEAR DEVELOPMENT OF THE GOLDREICH-SCHUBERT-FRICKE INSTABILITY IN A ROTATING ANNULUS SO ASTROPHYSICAL JOURNAL LA English DT Article DE HYDRODYNAMICS; INSTABILITIES; STARS, ROTATION ID GIANT PLANETS; EVOLUTION; STARS AB The Goldreich-Schubert-Fricke (GSF) instability may be an important mechanism affecting the angular momentum distribution of rotating stars and gaseous planets. This paper presents two-dimensional nonlinear hydrodynamic calculations which may help assess the effectiveness of the instability in transporting angular momentum in the equatorial zones of stars and planets which are stably stratified with respect to convection. The calculations were made by numerically integrating the two-dimensional axisymmetric Navier-Stokes equations, including viscosity and heat conduction. The initial state was that of a differentially rotating, stably stratified annulus in which angular momentum decreased with radius, and in which gravity was perpendicular to the rotation vector. In the absence of heat diffusion, the configuration would be stable because of the entropy stratification. The instability was followed into the nonlinear regime. The maximum rms velocity amplitude was found to correlate well with the product of the linear growth rate and radial length scale of the instability, consistent with the idea that the instability grows to an amplitude such that an eddy turnover time becomes equal to the growth time defined by the inverse of the growth rate. The time scale for angular momentum to be redistributed to a state of marginal stability was consistent with this picture. The results suggest that in physical situations a state of marginal stability will be maintained, since departures from such a state will be rapidly corrected. RP KORYCANSKY, DG (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. NR 15 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 1991 VL 381 IS 2 BP 515 EP 525 DI 10.1086/170675 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN112 UT WOS:A1991GN11200018 ER PT J AU MARISKA, JT ZARRO, DM AF MARISKA, JT ZARRO, DM TI SOFT-X-RAY EMISSION FROM ELECTRON-BEAM HEATED SOLAR-FLARES SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, FLARES; SUN, X-RAYS ID LOOP RADIATIVE HYDRODYNAMICS; NONTHERMAL ELECTRONS; MAXIMUM MISSION; CHROMOSPHERE; DYNAMICS AB Using time-dependent numerical simulations and Solar Maximum Mission (SMM) observations of a solar flare on 1985 January 23, we examine the ability of an electron-beam-heating model to reproduce the rise phase of a flare as observed in soft X-ray lines of Ca XIX. The electron beam is parameterized by a peak flux, a low-energy cutoff, and a spectral index, and has a time dependence similar to the observed hard X-ray burst. We find that for a spectral index of 6, only models with a low-energy cutoff of 20 keV reproduce the observed peak emission in the Ca XIX line complex. All models with a low-energy cutoff of 15 keV produce too much emission, while all models with a 25 keV cutoff too little emission. None of the models reproduces the temporal behavior of the soft X-ray emission. We conclude that the electron-beam-heated component may only represent a small fraction of the energy released in the impulsive phase of this flare. C1 NASA, LYNDON B JOHNSON SPACE CTR, APPL RES CORP, HOUSTON, TX 77058 USA. RP USN, RES LAB, EO HULBURT CTR SPACE RES, CODE 4175, WASHINGTON, DC 20375 USA. NR 17 TC 15 Z9 15 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 NOV 10 PY 1991 VL 381 IS 2 BP 572 EP 577 DI 10.1086/170681 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN112 UT WOS:A1991GN11200024 ER PT J AU GWINN, CR DANEN, RM MIDDLEDITCH, J OZERNOY, LM TRAN, TK AF GWINN, CR DANEN, RM MIDDLEDITCH, J OZERNOY, LM TRAN, TK TI THE GALACTIC-CENTER RADIO-SOURCE SHINES BELOW THE COMPTON LIMIT SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, NUCLEI; GALAXIES, THE GALAXY; INTERSTELLAR, MATTER; RADIO SOURCES, GENERAL ID REFRACTIVE INTERSTELLAR SCINTILLATION; BRIGHTNESS TEMPERATURES; A-STAR; PULSAR; SCATTERING; GALAXY; VLBI; MM AB Absence of refractive scintillation of Sgr A*, the Galactic center radio source, at 1.3 and 0.8 mm wavelengths places an observational limit of brightness temperature T(b) less-than-or-similar-to 0.5 x 10(12) K on the source. This is less than the maximum brightness of an incoherently synchrotron-emitting plasma, 10(12) K, known as the Compton limit. The refractive scintillations expected, due to strong broadening of the source by the interstellar plasma, are observed by Zhao et al. at decimeter wavelengths. We fail to observe them at 1.3 and 0.8 mm wavelengths over time spans between 0.1 s and 24 hr. Such scintillations are quenched by source size greater than about 0.1 AU, or, equivalently, T(b) < 0.5 x 10(12) K for Sgr A*, at 0.8 mm wavelength. The scintillations would also require fluctuations with scale sizes of 0.1 AU in the scattering plasma, moving across the line of sight at velocities V perpendicular-to greater-than-or-similar-to 100 km s-1. We argue that the plasma that scatters Sgr A* satisfies the latter two conditions, and that the absence of scintillations is due to the size of the source. Our observation strengthens the identification of Sgr A* as a quiescent galactic nucleus. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV CALIF SANTA BARBARA,COLL CREAT STUDIES,SANTA BARBARA,CA 93106. RP GWINN, CR (reprint author), UNIV CALIF SANTA BARBARA,DEPT PHYS,BROIDA HALL,SANTA BARBARA,CA 93106, USA. NR 35 TC 26 Z9 26 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 NOV 10 PY 1991 VL 381 IS 2 BP L43 EP L46 DI 10.1086/186192 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN115 UT WOS:A1991GN11500002 ER PT J AU KASTNER, SO BHATIA, AK AF KASTNER, SO BHATIA, AK TI N-III LINE EMISSION IN PLANETARY-NEBULAE - NOT BOWEN FLUORESCENCE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; GALAXIES, SEYFERT; LINE FORMATION; NEBULAE, GENERAL; STARS, EMISSION-LINE; X-RAYS, BINARIES ID MECHANISM; SPECTRUM AB A direct comparison of photometrically observed line ratios in the N III 4640 and 4100 angstrom multiplets emitted by planetary nebulae with theoretically predicted ratios expected from the postulated Bowen process of selective photoexcitation by an O III resonance line shows that the N III lines are not produced by the Bowen process as has been commonly accepted. This will have consequences for the interpretation of these lines in other astrophysical sources. A further, unexpected result is that the N III level populations involved are found to be essentially in statistical equilibrium. Possible populating mechanisms are briefly discussed. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & ASTROPHYS LAB,ASTRON BRANCH,GREENBELT,MD 20771. RP KASTNER, SO (reprint author), MATH SCI CONSULTANTS INC,1-A RIDGE RD,GREENBELT,MD 20770, USA. NR 19 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 NOV 10 PY 1991 VL 381 IS 2 BP L59 EP L62 DI 10.1086/186196 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN115 UT WOS:A1991GN11500006 ER PT J AU STOTHERS, RB CHIN, CW AF STOTHERS, RB CHIN, CW TI METAL OPACITIES AND CONVECTIVE CORE OVERSHOOTING IN POPULATION-I STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE CONVECTION; OPACITIES; STARS, ABUNDANCES; STARS, EVOLUTION; STARS, INTERIORS ID INTERMEDIATE-MASS STARS; B-TYPE STARS; EMPIRICAL CALIBRATIONS; EVOLUTIONARY MODELS; STELLAR EVOLUTION; DISTANCE SCALE; BETA-SYSTEMS; DIAGRAMS; TESTS; UVBY AB New stellar opacities computed by Rogers and Iglesias are found to lead to revised evolutionary models for stars of intermediate to high mass that show remarkably close agreement with observed stars, under otherwise standard physical assumptions. Most or all of the earlier discrepancies, except for the problem of predicted apsidal motion constants that are perhaps still too large, appear to have been resolved by using these new opacities with their increased metal line contribution. Thus, the implied interior metallicity of massive stars in the solar neighborhood now becomes "normal." Furthermore, the effective distance of convective overshooting beyond the classical convective core boundary is confirmed to be small and probably less than 0.2 times the local pressure scale height. RP STOTHERS, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 38 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 1991 VL 381 IS 2 BP L67 EP L70 DI 10.1086/186198 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GN115 UT WOS:A1991GN11500008 ER PT J AU KILBURN, CRJ LOPES, RMC AF KILBURN, CRJ LOPES, RMC TI GENERAL PATTERNS OF FLOW FIELD GROWTH - AA AND BLOCKY LAVAS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DE-LA-FOURNAISE; MOUNT ETNA; REUNION-ISLAND; IGNEOUS ROCKS; COSTA-RICA; RHEOLOGY; VOLCANO; DYNAMICS; MAGMA; TEMPERATURES AB Lava flow fields consist of one or more flows. Four ideal emplacement regimes are recognized: (a) that for single flows and (b) that for flow fields dominated by (1) widening, (2) thickening, or (3) lengthening, as a result of generating new flows. Most aa and blocky lavas belong to the flow field widening or single-flow regimes. These two regimes are analyzed assuming advance is controlled by the distal core of a flow, where motion is treated as steady, uniform, and laminar. Because of low deformation rates, the distal core is also approximated to a Newtonian fluid. Widening and, possibly, lengthening are ultimately limited by crustal resistance. After a critical cooling interval, new flows are generated from the upper reaches of the flow field. A simple relation is derived linking flow field dimensions and underlying slope to eruption duration, independent of terms involving gravity or lava chemistry and rheology. The relation well describes field data from several volcanoes (involving lava compositions from K phonolitic tephrite to dacite). This supports the premise that the overall growth of aa and blocky flow fields is systematic and also suggests that such growth may be predictable at time scales greater than, or similar to, the emplacement times of major flows. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP KILBURN, CRJ (reprint author), CTR SORVEGLIANZA,OSSERV VESUVIANO,VIA MANZONI 249,I-80123 NAPLES,ITALY. RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 92 TC 48 Z9 50 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-SOL EA JI J. Geophys. Res.-Solid Earth PD NOV 10 PY 1991 VL 96 IS B12 BP 19721 EP 19732 DI 10.1029/91JB01924 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ691 UT WOS:A1991GQ69100014 ER PT J AU LERCH, FJ MARSH, JG KLOSKO, SM PATEL, GB CHINN, DS PAVLIS, EC WAGNER, CA AF LERCH, FJ MARSH, JG KLOSKO, SM PATEL, GB CHINN, DS PAVLIS, EC WAGNER, CA TI AN IMPROVED ERROR ASSESSMENT FOR THE GEM-T1 GRAVITATIONAL MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GRAVITY MODEL; ACCURACY AB Several tests have been designed to estimate the correct error variances for the GEM-T1 gravitational solution that was derived exclusively from satellite tracking data. The basic method uses both independent and dependent subset data solutions and produces a coefficient by coefficient estimate of the model uncertainties. The GEM-T1 errors have been further analyzed using a method based on eigenvalue-eigenvector analysis, which calibrates the entire covariance matrix. Dependent satellite data sets and independent altimetric, resonant satellite, and surface gravity data sets all confirm essentially the same error assessment. The calibration test results yield very stable calibration factors, which vary only by approximately 10% over the range of tests performed. Based on these calibrated error estimates, GEM-T1 is a significantly improved solution, which to degree and order 8 is twice as accurate as earlier satellite derived models like GEM-L2. Also, by being complete to degree and order 36, GEM-T1 is more complete and has significantly reduced aliasing effects that were present in previous models. C1 ST SYST CORP,LANHAM,MD 20706. NATL GEODECT SURVEY,ROCKVILLE,MD 20852. UNIV MARYLAND,COLLEGE PK,MD 20742. RP LERCH, FJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770, USA. NR 15 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD NOV 10 PY 1991 VL 96 IS B12 BP 20023 EP 20040 DI 10.1029/91JB01480 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ691 UT WOS:A1991GQ69100033 ER PT J AU SPALL, RE GATSKI, TB AF SPALL, RE GATSKI, TB TI A COMPUTATIONAL STUDY OF THE TOPOLOGY OF VORTEX BREAKDOWN SO PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID NAVIER-STOKES EQUATIONS; FLOW; CONTAINER; STABILITY AB A fully three-dimensional numerical simulation of vortex breakdown using the unsteady, incompressible Navier-Stokes equations has been performed. Solutions to four distinct types of breakdown are identified and compared with experimental results. The computed solutions include weak helical, double helix, spiral, and bubble-type breakdowns. The topological structure of the various breakdowns as well as their interrelationship are studied. The data reveal that the asymmetric modes of breakdown may be subject to additional breakdowns as the vortex core evolves in the streamwise direction. The solutions also show that the freestream axial velocity distribution has a significant effect on the position and type of vortex breakdown. C1 HIGH TECHNOL CORP,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. NR 39 TC 24 Z9 24 U1 0 U2 2 PU ROYAL SOC LONDON PI LONDON PA 6 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5AG SN 1364-5021 J9 P ROY SOC LOND A MAT JI Proc. R. Soc. London Ser. A-Math. Phys. Eng. Sci. PD NOV 8 PY 1991 VL 435 IS 1894 BP 321 EP 337 DI 10.1098/rspa.1991.0147 PG 17 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GQ399 UT WOS:A1991GQ39900007 ER PT J AU VIERECK, RA MURAD, E GREEN, BD JOSHI, P PIKE, CP HIEB, R HARBAUGH, G AF VIERECK, RA MURAD, E GREEN, BD JOSHI, P PIKE, CP HIEB, R HARBAUGH, G TI ORIGIN OF THE SHUTTLE GLOW SO NATURE LA English DT Article ID VEHICLE GLOW; SURFACE; SATELLITE; NO2 AB A GLOW around exposed surfaces of the space shuttle facing the direction of orbital motion was first seen in 1983 1,2. This 'shuttle glow' extends about 10 cm from the surfaces, is peaked in wavelength at 680 nm, and within a resolution of about 3.5 nm forms a continuum 3-6. Similar anomalies were reported in rocket experiments as long ago as 1958 7 and in more recent space-based studies 8. Apart from its interest as an unusual physical phenomenon, shuttle glow may be a source of interference in space-based spectroscopy; anomalous airglow observations made by the Atmospheric Explorer spacecraft 9,10 have been attributed to it. The most likely explanation seems to be the recombination of fast oxygen atoms in the upper atmosphere with NO absorbed on the shuttle's surface. This forms excited NO2, which radiates light as it desorbs 6,7. On a recent shuttle mission (STS-39) four gases, NO, CO2, Xe and Ne were released for a plasma experiment. Unintentionally, enough gas was scattered onto the surfaces of the shuttle tail that when NO was released a much more intense version of shuttle glow was observed. The other gases did not affect the normal shuttle glow. Under normal conditions the adsorbed NO that causes the glow probably comes either from the ambient atmosphere 6 or from reactions in exhaust gases from the shuttle thrusters 14,15. C1 PHYS SCI INC,ANDOVER,MA 01810. NASA,JOHNSON SPACE CTR,HOUSTON,TX 77001. RP VIERECK, RA (reprint author), PHILLIPS LAB,BEDFORD,MA 01731, USA. NR 26 TC 19 Z9 19 U1 1 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD NOV 7 PY 1991 VL 354 IS 6348 BP 48 EP 50 DI 10.1038/354048a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GN829 UT WOS:A1991GN82900052 ER PT J AU SEAMANS, RC AF SEAMANS, RC TI IMPROVING UNITED-STATES COMMERCIAL COMPETITIVENESS SO AEROSPACE AMERICA LA English DT Article RP SEAMANS, RC (reprint author), NASA,WASHINGTON,DC 20546, 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 NOV PY 1991 VL 29 IS 11 BP B32 EP B32 PG 1 WC Engineering, Aerospace SC Engineering GA GN858 UT WOS:A1991GN85800012 ER PT J AU BATINA, JT AF BATINA, JT TI IMPLICIT FLUX-SPLIT EULER SCHEMES FOR UNSTEADY AERODYNAMIC ANALYSIS INVOLVING UNSTRUCTURED DYNAMIC MESHES SO AIAA JOURNAL LA English DT Article ID EQUATIONS AB Improved algorithms for the solution of the time-dependent Euler equations are presented for unsteady aerodynamic analysis involving unstructured dynamic meshes. The improvements have been developed recently to the spatial and temporal discretizations used by unstructured grid flow solvers. The spatial discretization involves a flux-split approach, which is naturally dissipative and captures shock waves sharply with at most one grid point within the shock structure. The temporal discretization involves an implicit time-integration scheme using a Gauss-Seidel relaxation procedure, which is computationally efficient for either steady or unsteady flow problems. For example, very large time steps may be used for rapid convergence to steady state, and the step size for unsteady cases may be selected for temporal accuracy rather than for numerical stability. Steady and unsteady flow results are presented for the NACA 0012 airfoil to demonstrate applications of the new Euler solvers. The unsteady results were obtained for the airfoil pitching harmonically about the quarter chord. The resulting instantaneous pressure distributions and lift and moment coefficients during a cycle of motion compare well with experimental data. The paper presents a description of the Euler solvers along with results and comparisons that assess the capability. RP BATINA, JT (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,UNSTEADY AERODYNAM BRANCH,MAIL STOP 173,HAMPTON,VA 23665, USA. NR 21 TC 20 Z9 20 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 NOV PY 1991 VL 29 IS 11 BP 1836 EP 1843 DI 10.2514/3.10808 PG 8 WC Engineering, Aerospace SC Engineering GA GM809 UT WOS:A1991GM80900009 ER PT J AU BONANNI, DL JOHNSON, ER STARNES, JH AF BONANNI, DL JOHNSON, ER STARNES, JH TI LOCAL CRIPPLING OF THIN-WALLED GRAPHITE-EPOXY STIFFENERS SO AIAA JOURNAL LA English DT Article AB Results from an experimental and analytical study of the local buckling, postbuckling, and crippling (failure) behavior of channel, zee, and I- and J-section stiffeners made of AS4/3502 graphite-epoxy unidirectional tape are presented. Thirty-six specimens were tested in axial compression. Experimental results indicate the existence of a number of damage-initiation modes, all of which involve either delamination in some part of the specimen or local material strength failure in a corner of the specimen. The flange width-to-thickness ratio is found to influence the mode of damage initiation. The inner corner radius strongly affects the crippling stress for the I- and J-section specimens, but was not found to have a significant effect on the crippling stress of channels and zees. Geometrically nonlinear analyses of five specimens were performed with the STAGS general-purpose computer code. Correlation between analytical and experimental results is excellent through buckling, but agreement degrades in postbuckling. The discrepancies in postbuckling are attributed to the neglect of transverse shearing deformations in the analysis and development of damage in the specimens. The maximum compressive fiber stress-failure criterion correlates reasonably well with the first major damage event observed in the tests. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT AEROSP & OCEAN ENGN,BLACKSBURG,VA 24061. NASA,LANGLEY RES CTR,DIV STRUCT MECH,AIRCRAFT STRUCT BRANCH,HAMPTON,VA 23665. RP BONANNI, DL (reprint author), DAVID TAYLOR RES CTR,BETHESDA,MD 20034, USA. NR 21 TC 8 Z9 8 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 NOV PY 1991 VL 29 IS 11 BP 1951 EP 1959 DI 10.2514/3.10824 PG 9 WC Engineering, Aerospace SC Engineering GA GM809 UT WOS:A1991GM80900025 ER PT J AU APPELGREN, BH THRASHER, TN KEIL, LC RAMSAY, DJ AF APPELGREN, BH THRASHER, TN KEIL, LC RAMSAY, DJ TI MECHANISM OF DRINKING-INDUCED INHIBITION OF VASOPRESSIN SECRETION IN DEHYDRATED DOGS SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE THIRST; ANTIDIURETIC HORMONE; PLASMA OSMOLALITY; OROPHARYNGEAL RECEPTORS; HEPATOPORTAL RECEPTORS; OSMORECEPTORS ID PLASMA VASOPRESSIN; RELEASE; HUMANS AB Ingestion of water stimulates a powerful inhibitory input to secretion of arginine vasopressin (AVP) in many species. A previous study in dogs has suggested that the stimulus arises from activation of oropharyngeal receptors, but the nature of the stimulus is unknown. The objectives of this study were to determine if the taste, osmolality, or temperature of the solution ingested constituted an important element in the inhibitory mechanism and if these same attributes affected the volume ingested in response to 24 h of water deprivation in conscious dogs. Experiments consisted of a control period, a 6-min period of access to fluid, and a 60-min period after drinking, with blood samples taken frequently to assess changes in plasma AVP. Dogs were placed in a sling that allowed them to stand or lie supported with easy access to a bowl. The solutions were water at 20 and 38-degrees-C; 0.9% NaCl at 20 and 38-degrees-C; 1.8 and 2.7% NaCl at 20-degrees-C; 5% glucose and mannitol and 10% mannitol at 20-degrees-C; and liquified food at 20-degrees-C. In the time-control experiment dogs were allowed to see but not drink water for 6 min. Results suggested that drinking-induced inhibition of AVP secretion consists of two phases: the first, lasting up to 9 min, is consistent with a complete cessation of AVP secretion and appears to be caused by the act of drinking itself because altering the taste, osmolality, or temperature of the solution had no effect on the inhibitory mechanism; in the second AVP secretion may either remain low, e.g., plasma AVP continues to fall after drinking water, or secretion may increase, e.g., plasma AVP increased after drinking solutions isotonic or hypertonic to body fluids. Thus AVP secretion in this phase appears to depend on changes in peripheral plasma osmolality. The mechanism that meters intake of fluid in response to the 24 h of water deprivation also appears to be relatively independent of the taste, osmolality, and temperature of the fluid consumed in the dog because intakes of all the test solutions were similar to the intake of water. C1 UNIV CALIF SAN FRANCISCO,SCH MED,DEPT PHYSIOL,BOX 0444,SAN FRANCISCO,CA 94143. KAROLINSKA INST,DEPT PHYSIOL & ORAL CLIN PHYSIOL,S-10401 STOCKHOLM 60,SWEDEN. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 16 TC 27 Z9 27 U1 1 U2 4 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 NOV PY 1991 VL 261 IS 5 BP R1226 EP R1233 PN 2 PG 8 WC Physiology SC Physiology GA GQ781 UT WOS:A1991GQ78100068 ER PT J AU STABENAU, EK VANOYE, CG HEMING, TA AF STABENAU, EK VANOYE, CG HEMING, TA TI CHARACTERISTICS OF THE ANION TRANSPORT-SYSTEM IN SEA-TURTLE ERYTHROCYTES SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE BAND-3; ANION EXCHANGE; ERYTHROCYTE; LEPIDOCHELYS; REPTILE ID RED-BLOOD-CELL; CHLORIDE-BICARBONATE EXCHANGE; BAND-3 PROTEIN; HCO3--CL EXCHANGE; GAS-EXCHANGE; SITES; KINETICS; MEMBRANE; CLEAVAGE; BINDING AB Erythrocytes of Kemp's ridley sea turtle (Lepidochelys kempi) contain a 100- to 105-kDa protein that is reactive with a monoclonal antibody to the membrane domain of human erythrocyte band 3. Based on inhibition of membrane HCO3--Cl- exchange with 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), sea turtle erythrocytes were found to contain 4 x 10(6) copies of band 3 per cell. Unidirectional HCO3- transfer, specifically HCO3 out --> in--Cl-in --> out exchange, where subscript in --> out represents transfer from inside to outside and subscript out --> in represents transfer from outside to inside, was characterized by a maximal exchange rate of 1.0-1.1 nmol.cm-2.s-1, substrate affinity coefficients of 0.1-0.2 mM for HCO3- and 1.6 mM for Cl-, and an apparent inhibition constant for SITS of 0.6-1.0-mu-M (10-degrees-C, pH 7.6). Under physiological conditions (30-degrees-C, pH 7.4), the rate of net HCO3- transfer (i.e., the difference between HCO3 in --> out--Cl-out --> in and HCO3 out --> in--Cl-in --> out) was 1.13 nmol.cm-2.s-1 for cells subject to a 5-mM decrement in CO2 content. This yields a rate coefficient for the "physiological" anion shift in sea turtle blood of 1.7 s-1, indicating that the anion shift may require 2.6 s to reach 99% completion in vivo. The erythrocyte anion shift appears to be a potential rate-limiting step for capillary CO2 exchange in these turtles. C1 UNIV TEXAS,MED BRANCH,PULM RES LABS,GALVESTON,TX 77550. NOAA,NATL MARINE FISHERIES SERV,GALVESTON,TX 77550. NR 34 TC 10 Z9 10 U1 2 U2 3 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 NOV PY 1991 VL 261 IS 5 BP R1218 EP R1225 PN 2 PG 8 WC Physiology SC Physiology GA GQ781 UT WOS:A1991GQ78100067 ER PT J AU PETERSON, DB PICKETT, HM AF PETERSON, DB PICKETT, HM TI CRYOGENIC FAR-INFRARED FABRY-PEROT ETALON SO APPLIED OPTICS LA English DT Article DE FABRY-PEROT; FAR-INFRARED; OPTICAL FILTERS ID INTERFEROMETER; FILTERS AB A small cryogenic Fabry-Perot etalon was fabricated for the far-infrared region. This design used freestanding metal meshes for the reflecting elements. Using a combination of gold-coated copper mesh on stainless steel, we reproduced the spacing to 1 part in 10(6) with repeated cooling. The properties and methods used for alignment and calibration are presented. RP PETERSON, DB (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD NOV 1 PY 1991 VL 30 IS 31 BP 4493 EP 4495 PG 3 WC Optics SC Optics GA GT889 UT WOS:A1991GT88900014 PM 20717238 ER PT J AU WEISTROP, D DOWNES, RA AF WEISTROP, D DOWNES, RA TI EMISSION-LINE GALAXIES IN THE 3RD LIST OF THE CASE LOW-DISPERSION NORTHERN SKY SURVEY SO ASTRONOMICAL JOURNAL LA English DT Article ID COMPLETE SAMPLE; SPECTRA; BOOTES; REGION; CLASSIFICATION AB Spectra have been obtained for 47 galaxies in the third list of the Case Low-Dispersion Northern Sky Survey, which covers an area R.A. = 08h05m-10h10m, Dec. = + 33.0-degrees- + 38.0-degrees. Thirty-five of the galaxies in the sample were selected for the presence of emission lines on the objective prism plates. At the higher spectral dispersion of our data, significant line emission was found in 46 of the 47 galaxies. Twenty-six galaxies are undergoing significant bursts of star formation. Ten additional galaxies may be starburst galaxies with low-excitation spectra. Two galaxies are probably type Seyfert 2. The most distant object, CG 200, at a redshift z = 0.144, has a strong, broad H-alpha emission line, and is probably a Seyfert 1. Seventeen of the galaxies have been detected by IRAS. Eight of the IRAS galaxies have H II region-type spectra and eight have low-ionization starburst spectra. The galaxies represent a mixture of types, ranging from intrinsically faint dwarf galaxies with M(B) = - 16 mag, to powerful galaxies with M(B) = - 23 mag. Galaxies CG 234, CG 235 are interacting, as are galaxies CG 269, CG 270. C1 NASA,GODDARD SPACE FLIGHT CTR,DIV SPACE DATA & COMP,GREENBELT,MD 20771. RP WEISTROP, D (reprint author), UNIV NEVADA,DEPT PHYS,LAS VEGAS,NV 89154, USA. OI Weistrop, Donna/0000-0001-8935-0792 NR 28 TC 15 Z9 15 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 NOV PY 1991 VL 102 IS 5 BP 1680 EP 1690 DI 10.1086/115987 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL774 UT WOS:A1991GL77400006 ER PT J AU CARILLI, CL BARTEL, N LINFIELD, RP AF CARILLI, CL BARTEL, N LINFIELD, RP TI VLBI OBSERVATIONS OF THE NUCLEAR JET IN CYGNUS-A SO ASTRONOMICAL JOURNAL LA English DT Article ID RADIO-SOURCES; MOTION; GALAXY AB We present an image of the "core" and inner jet of Cygnus A at an angular resolution of 2 mas obtained from Mark III VLBI observations at 6 cm wavelength with an array of nine antennas. The core is resolved, at least partly due to its being broadened by scattering in the Galactic interstellar medium. The jet has several condensations out to a distance of approximately 25 mas from the core and has a fairly constant FWHM of approximately 2.2 mas. The parsec-scale jet points toward the arcsec-scale jet observed with the VLA to within 4-degrees. The ratio between the flux density of the jet and that of the counterjet is > 15:1. From a comparison with an earlier VLBI image of Cygnus A, we find an upper limit to the apparent velocity of the brightest knot in the jet of about 2c, where c is the speed of light (for H0 = 60 km s-1 Mpc-1,q0 = 0). C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP CARILLI, CL (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 32 TC 18 Z9 18 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 NOV PY 1991 VL 102 IS 5 BP 1691 EP 1695 DI 10.1086/115988 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL774 UT WOS:A1991GL77400007 ER PT J AU SEKANINA, Z AF SEKANINA, Z TI RANDOMIZATION OF DUST-EJECTA MOTIONS AND THE OBSERVED MORPHOLOGY OF COMETARY HEADS SO ASTRONOMICAL JOURNAL LA English DT Article ID EMISSION PATTERN; COMA MORPHOLOGY; SPIN VECTOR; NUCLEUS; HALLEY; MODEL; JETS AB The computer code that has been used over years to study the dust-coma morphology of comets and to generate their synthetic images is upgraded by introducing two categories of random perturbations into the motions of dust particles ejected from discrete sources of activity on the nucleus surface. The new technique is applied to three types of morphological features: multiple concentric halos, a system of spiral jets, and a sunward fan-shaped coma. The results indicate that inclusion of random perturbations substantially enhances the capability for generating synthetic images that faithfully simulate the observed appearance of dust comets. By increasing the magnitude of perturbations in the synthetic images beyond a certain limit, it is possible to "erase" morphological features characteristic of the ejection process. This implies that the lack of distinct morphology in the head of a comet cannot be interpreted as the absence of discrete sources of activity on the nucleus surface. The effects of varying random perturbations on the appearance of the computer-generated images are investigated in detail and the suspected major role that imperfect flow collimation (or flow divergence) in dust jets plays with regard to the observed coma morphology is discussed. RP SEKANINA, Z (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 22 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 1991 VL 102 IS 5 BP 1870 EP 1878 DI 10.1086/116009 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL774 UT WOS:A1991GL77400028 ER PT J AU TREUHAFT, RN LOWE, ST AF TREUHAFT, RN LOWE, ST TI A MEASUREMENT OF PLANETARY RELATIVISTIC DEFLECTION SO ASTRONOMICAL JOURNAL LA English DT Article ID BASELINE RADIO INTERFEROMETRY; ASTROMETRY AB The radio interferometric observations described here constitute the first measurement of the deflection of electromagnetic radiation by a planetary gravitational field. They also demonstrate a few hundred microarcsecond (mu-arcsec) angular astrometric technique, which can be applied over many-degree fields of sky. The ray path of the radio source P0201 + 113 passed within 200 arcsec of Jupiter (almost-equal-to 10 Jovian radii) on 21 March 1988. Its angular position was measured 10 times over 4 hr on that date, with a similar measurement set on 2 April 1988 to detect the differential angular deflection of the ray path. According to general relativity, the expected gravitational bend of the ray path averaged over the March experiment duration was approximately 300-mu-arcsec, projected onto the two California-Australia baselines over which it was measured. Measurement accuracies of the order of 160-mu-arcsec were obtained for each of the ten differential measurements. The chi-2 per degree of freedom of the data for the hypothesis of general relativity was 0.6, suggesting that the modeled dominant errors due to system noise and tropospheric fluctuations fully accounted for the scatter in the measured angular deflections. The chi-2 per degree of freedom for the hypothesis of no gravitational deflection by Jupiter was 4.1, which rejects the no-deflection hypothesis with greater than 99.999% confidence. The system noise contributed about 70-mu-arcsec per combined-baseline differential measurement and tropospheric fluctuations contributed about 145-mu-arcsec. Unmodeled errors were assessed which could potentially increase the 160-mu-arcsec error by about 8%. RP TREUHAFT, RN (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 37 TC 29 Z9 29 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 NOV PY 1991 VL 102 IS 5 BP 1879 EP 1888 DI 10.1086/116010 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL774 UT WOS:A1991GL77400029 ER PT J AU TAGLIAFERRI, G WHITE, NE DOYLE, JG CULHANE, JL HASSALL, BJM SWANK, JH AF TAGLIAFERRI, G WHITE, NE DOYLE, JG CULHANE, JL HASSALL, BJM SWANK, JH TI A STUDY OF THE FLARING AND QUIESCENT X-RAY AND UV EMISSION FROM II-PEGASI SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE RS CVN TYPE STARS, II-PEG; FLARE; X-RAYS; ULTRAVIOLET EMISSION ID RS CANUM VENATICORUM; DRA-TYPE STARS; ROTATIONAL MODULATION; AR-LAC; PHYSICAL PARAMETERS; EXOSAT OBSERVATION; IUE OBSERVATIONS; DRACONIS STARS; SIGMA-2 CRB; FLARES AB An EXOSAT-IUE observation campaign of the RS CVn system 11 Peg was made in July 1985, in order to investigate the rotational modulation of the transition region UV and coronal X-ray emission. The spectrum of the quiescent emission in the 1-6 keV band is well fitted to a single temperature of approximately 2 10(7) K. Adding the 0.05-2 keV band, we find a second softer component of temperature approximately 5 10(6) K, in some, but not all, observations. The X-ray light curve is dominated by a strong flare detected at orbital phase where the minimum of the photometric wave occurred. The flare is seen also in the UV band, with an increase of about a factor two in the Si IV, C IV and He II lines. In the energy range 1-6 keV the rise time of the flare was approximately 9000 s, with an exponential decay of 40 000 s. The 0.05-10 keV peak luminosity was 1.1 10(31) ergs-1, more than 7 times the quiescent value, with a peak temperature of 3.7 10(7) K. The derived flare parameters indicate that the flare originates in a loop with a height of approximately 10(11) cm, more than half the stellar radius. The characteristics of the flare are similar to those of a solar two-ribbon flare. The electron density of the flare in the mid-transition region is 4 10(9) cm-3, being similar to that of the quiescent atmosphere, re-enforcing the conclusion from the X-ray data that we are observing a low-density coronal-type event. Comparing the mid-transition region density with that in the coronal region, there is a very steep pressure gradient, since the electron density derived from the X-ray data is approximately 2.7 10(10) cm-3. The emitted X-ray and UV energy throughout the flare is more than 2 10(35) ergs. C1 ARMAGH OBSERV, ARMAGH BT61 9DG, NORTH IRELAND. UNIV LONDON UNIV COLL, MULLARD SPACE SCI LAB, DORKING, SURREY, ENGLAND. UNIV OXFORD, DEPT ASTROPHYS, OXFORD OX1 3RH, ENGLAND. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP TAGLIAFERRI, G (reprint author), EUROPEAN SPACE TECHNOL CTR, SAE,EUROPEAN SPACE AGCY,DEPT SPACE SCI, EXOSAT OBSERV, KEPLERLAAN 1, 2200 AG NOORDWIJK, NETHERLANDS. RI White, Nicholas/B-6428-2012; Swank, Jean/F-2693-2012 OI White, Nicholas/0000-0003-3853-3462; NR 37 TC 18 Z9 18 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 NOV PY 1991 VL 251 IS 1 BP 161 EP 170 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM776 UT WOS:A1991GM77600023 ER PT J AU GUDEL, M ASCHWANDEN, MJ BENZ, AO AF GUDEL, M ASCHWANDEN, MJ BENZ, AO TI THE ASSOCIATION OF SOLAR MILLISECOND RADIO SPIKES WITH HARD X-RAY-EMISSION SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE SUN, RADIO RADIATION; SUN, X-RAYS; X-RAYS, BURSTS; SUN, BURSTS; SUN, ACTIVITY ID BURSTS; FLARES; ELECTRONS AB A large set of decimetric and microwave observations of solar millisecond radio spikes is compared and correlated with simultaneous hard X-ray observations in the 25-438 keV range, recorded by the Hard X-Ray Burst Spectrometer (HXRBS) on board the Solar Maximum Mission satellite. Radio spikes have time scales of 20-200 ms, while hard X-ray bursts rarely show fine structures shorter than 1 s. The main conclusions of a statistical analysis of a) the association rate, b) the correlation degree, and c) relative time delays between hard X-ray and radio spike emissions, are: 1) Radio spike bursts reveal the highest hard X-ray association rate of any kind of coherent solar radio emission; approximately 95% of the observed events occur during (mostly impulsive) hard X-ray bursts. Conversely, almost-equal-to 2% of all HXRBS flares produce radio millisecond spike bursts. 2) Spike bursts are preferentially associated with the impulsive phase of the hard X-ray event; about half of all observations are closely associated with the main peak of a simultaneous X-ray event. 3) We find a significant temporal correlation between spike clusters and hard X-ray events. About 43% of the compared events show hard X-ray time profiles that mimic the concentration of simultaneous radio spikes. This also holds for small fluctuations with time scales of the order of a few seconds. 4) The durations of spike events and associated hard X-ray bursts closely correlate, the X-ray bursts being somewhat longer than the radio events. 5) The radio emission is usually delayed in respect to hard X-ray bursts, typically a few seconds. The relative delays seem to be restricted to the following rules: The radio event usually starts before the peak time of the hard X-ray event (73 out of 84 cases), and similarly, the X-ray burst almost always starts before the maximum of spike burst activity (83 out of 84 cases). This is shown to hold for a wide range of burst durations. We have not found any convincing relation concerning the relative time differences of the end times, however. 6) The observed delays of the order of several seconds put some constraints on the acceleration and propagation of particles. The delays are found to be incompatible with the build-up time of a loss-cone distribution (for maser emission) by an order of magnitude, if the, same population of electrons is responsible for radio and X-ray radiation. Rather, considering the smallness of the radio spike sources, the proportionality of the X-ray flux with the spike rate, and the spatial 'spread of a propagating electron population, it is argued that both the time delays and the quantization into discrete radio events are caused by the operation of the accelerator. C1 SWISS FED INST TECHNOL, INST ASTRON, CH-8092 ZURICH, SWITZERLAND. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RI Guedel, Manuel/C-8486-2015 OI Guedel, Manuel/0000-0001-9818-0588 NR 34 TC 45 Z9 46 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 NOV PY 1991 VL 251 IS 1 BP 285 EP 297 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM776 UT WOS:A1991GM77600036 ER PT J AU SREEKUMAR, P FICHTEL, CE AF SREEKUMAR, P FICHTEL, CE TI COSMIC-RAYS IN THE SMALL MAGELLANIC CLOUD SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE COSMIC RAYS, GENERAL; GALAXIES, MAGELLANIC CLOUDS; GAMMA RAYS, GENERAL ID RADIO-CONTINUUM SURVEY; GAMMA-RADIATION; 1.4 GHZ; GALAXY; DISTANCE; EMISSION AB A study is made of the Small Magellanic Cloud (SMC) in an attempt to determine whether this galaxy is in dynamic quasi-stable equilibrium between the expansive pressure of the hot cosmic ray gas, the magnetic fields, and the kinetic motion of interstellar gas and the gravitational attraction of matter. The intensity and distribution of cosmic rays in the SMC as compared to our galaxy may be deduced from the measurements of synchrotron radiation arising from the interaction of the energetic electrons with the ambient magnetic field assuming, as can be shown to be reasonable, the same ratio of cosmic ray electrons to nucleons as in our galaxy. It is concluded that the cosmic ray density level is three to five times smaller than that which would exist if the galaxy were in approximate dynamic equilibrium and the cosmic ray sources were adequate. Further, the scale of coupling between the cosmic rays and matter in the projected dimension that can be observed is < 1/2 kpc, which is rather small to be consistent with a stable cosmic ray distribution. The conclusion that the cosmic ray density in the SMC is lower than that if the conditions of dynamic equilibrium were in place for the SMC as a whole and substantially lower than that in our galaxy is in contrast with that for the LMC, where the cosmic ray intensity has been shown to be consistent with dynamic quasi-stable equilibrium, and similar to that in the local region of our galaxy. Using the observed matter distribution and the calculated cosmic ray density distribution, the expected gamma ray intensity distribution is determined. The resulting flux integrated over the SMC region is found to be approximately 1 10(-8) photons (E > 100 MeV) cm-2 s-1, 5 to 25 times smaller than the previous estimates based on quasi-stable equilibrium or a similar cosmic ray density. RP SREEKUMAR, P (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 662, GREENBELT, MD 20771 USA. NR 47 TC 12 Z9 12 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 NOV PY 1991 VL 251 IS 2 BP 447 EP 453 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GP636 UT WOS:A1991GP63600017 ER PT J AU JACOBSON, RA AF JACOBSON, RA TI TRITON AND NEREID ASTROGRAPHIC OBSERVATIONS FROM VOYAGER-2 SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE ASTROMETRY; NEREID; SATELLITES OF NEPTUNE; TRITON; AND VOYAGER ID DEIMOS ASTROMETRIC OBSERVATIONS; PHOBOS AB This article describes the reduced astrographic observations of Triton and Nereid derived from Voyager 2 imaging data. The data set contains 496 sets of spacecraft-centered right ascension and declination observations and includes all of the observations used in Voyager encounter operations. The details of the conversion process from imaging to astrographic observations are given. The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated. RP JACOBSON, RA (reprint author), CALTECH,JET PROP LAB,301-150,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 10 TC 7 Z9 7 U1 0 U2 1 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 NOV PY 1991 VL 90 IS 3 BP 541 EP 563 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL014 UT WOS:A1991GL01400006 ER PT J AU TURNER, TJ WEAVER, KA MUSHOTZKY, RF HOLT, SS MADEJSKI, GM AF TURNER, TJ WEAVER, KA MUSHOTZKY, RF HOLT, SS MADEJSKI, GM TI EINSTEIN-OBSERVATORY SSS AND MPC OBSERVATIONS OF THE COMPLEX-X-RAY SPECTRA OF SEYFERT-GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, SEYFERT; GALAXIES, X-RAYS; RADIATION MECHANISMS ID ACTIVE GALACTIC NUCLEI; COLD MATTER; QUASARS; ABSORPTION; NGC-4151; EXOSAT; VARIABILITY; CONSTRAINTS; MCG-6-30-15; NGC-7469 AB We have reinvestigated the X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. We find that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for approximately 48% of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. UNIV MARYLAND,COLLEGE PK,MD 20742. RP TURNER, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 666,GREENBELT,MD 20771, USA. NR 58 TC 107 Z9 107 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 NOV 1 PY 1991 VL 381 IS 1 BP 85 EP 100 DI 10.1086/170631 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500009 ER PT J AU KENNEY, JDP LORD, SD AF KENNEY, JDP LORD, SD TI ORBIT CROWDING OF MOLECULAR GAS AT A BAR-SPIRAL ARM TRANSITION ZONE IN M83 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (M83); GALAXIES, INTERSTELLAR MATTER; GALAXIES, STRUCTURE; INTERSTELLAR, MOLECULES; STARS, FORMATION ID CLOUD-CLOUD COLLISIONS; STAR FORMATION; DENSITY WAVES; CARBON-MONOXIDE; GALAXY M83; DYNAMICS; KINEMATICS; M51; SUPERCLOUDS; LUMINOSITY AB High-resolution (9" x 6") CO (J = 1 --> 0) observations in the barred spiral galaxy M83 reveal a massive molecular gas complex associated with luminous H II regions at the southern bar-spiral arm transition zone. The cloud complex is resolved into two principal components, one of which is clearly linked to the bar, the other to the spiral arm. The bar component is located along a ridge of highly polarized radio continuum emission at the place where the ridge bends away from following the bar to following the spiral arm. The spiral arm component is located at the same galaxy azimuth as the bar component, but 250 pc further out in radius, just upstream from a ridge of H II regions on the spiral arm. Gas dynamical mechanisms are identified which impart a shear in this region, giving the spiral arm component a tangential velocity 60 km s-1 (in the plane of the disk) greater than the bar component. Numerous bright H II regions are associated with the spiral arm gas, but very few are associated with the bar gas, suggesting that massive stars form more efficiently in the spiral arms than on the bar. The CO morphology and kinematics are consistent with the entire molecular complex originating through orbit crowding, in which gas on highly elliptical orbits from the bar region converges with gas on more circular orbits from the region just beyond the bar. The orbit crowding is strongly enhanced by radial streaming motions due to density waves, which are in opposite directions along the bar and spiral arm, thereby producing a region of streamline convergence where the bar meets the spiral arm. The regions of enhanced massive star formation near the bar ends of many barred galaxies are probably due to orbit crowding effects like those observed in M83. C1 NASA,AMES RES CTR,ASTROPHYS BRANCH,MOFFETT FIELD,CA 94035. RP KENNEY, JDP (reprint author), CALTECH,DEPT ASTRON 10524,PASADENA,CA 91125, USA. NR 54 TC 61 Z9 61 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 NOV 1 PY 1991 VL 381 IS 1 BP 118 EP 129 DI 10.1086/170634 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500012 ER PT J AU LORD, SD KENNEY, JDP AF LORD, SD KENNEY, JDP TI A MOLECULAR GAS RIDGE OFFSET FROM THE DUST LANE IN A SPIRAL ARM OF M83 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (M83); GALAXIES, INTERSTELLAR MATTER; INTERSTELLAR, MOLECULES ID CLOUD-CLOUD COLLISIONS; H-II REGIONS; STAR FORMATION; GALAXIES; M51; KINEMATICS; DYNAMICS; MASS; CALIBRATION; SUPERCLOUDS AB We present a high-resolution (5" x 12") interferometric map of the CO (J = 1 --> 0) emission on the eastern spiral arm of M83. The detected emission originates in about five unresolved components located parallel but approximately 300 pc downstream from the dust lane which lies along the inner edge of the spiral arm. With one exception, the CO components in our map are all located within 130 pc of an H II region, and may represent emission from locally heated gas. While heating by H II regions may enhance the CO luminosity in the arm, the lack of CO emission on the dust lane indicates that the dense molecular gas does not pile up here in M83. The distribution of molecular emission in this spiral arm of M83 is shown to be remarkably different from the spiral arms of M51, where CO emission peaks on the dust lane. The difference between the molecular gas distributions in the two galaxies is attributed to the difference in the strength of their density waves. The observations of M83 are consistent with the model of Elmegreen, in which diffuse gas is compressed at the shock front producing the dust lane at the inner edge of the spiral arm, while dense giant molecular clouds pass through the front and form a broad distribution on the arm. In M51, with its significantly stronger density wave, both diffuse and dense gas are concentrated in a collision front located at the inner edge of the spiral arm, coincident with the dust lane. C1 CALTECH,DEPT ASTRON 10524,PASADENA,CA 91125. RP LORD, SD (reprint author), NASA,AMES RES CTR,ASTROPHYS BRANCH,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 51 TC 35 Z9 35 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1991 VL 381 IS 1 BP 130 EP & DI 10.1086/170635 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500013 ER PT J AU TIELENS, AGGM TOKUNAGA, AT GEBALLE, TR BAAS, F AF TIELENS, AGGM TOKUNAGA, AT GEBALLE, TR BAAS, F TI INTERSTELLAR SOLID CO - POLAR AND NONPOLAR INTERSTELLAR ICES SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SPECTRA; INTERSTELLAR, GRAINS; INTERSTELLAR, MATTER; STARS, PRE-MAIN-SEQUENCE ID COMPACT INFRARED SOURCES; TAURUS DARK CLOUDS; CARBON-MONOXIDE; ABSORPTION FEATURES; MOLECULAR CLOUDS; ALPHA-CO; SPECTRA; SPECTROSCOPY; MATRICES; GRAINS AB We present moderate-resolution (lambda/DELTA-lambda almost-equal-to 1200) observations of the solid CO band in a sample of protostars. The spectra reveal two independent solid CO components along most lines of sight. One produces a narrow (DELTA-nu almost-equal-to 5 cm-1) band generally centered at about 2140 cm-1 and the other a broader (DELTA-nu almost-equal-to 10 cm-1) one at about 2136 cm-1. Both the peak position and width of the narrow, and generally strongest, component vary from object to object. The relative strengths of the two components vary considerably in this sample. Laboratory studies of the shape and peak position of the solid CO band in astrophysically relevant mixtures show that the narrow CO band occurs in mixtures dominated by non-polar molecules (e.g., CO itself, CO2, O2, N2), while the broad feature is due to more polar mixtures, such as H2O ice. Calculations show that for mixtures dominated by CO (CO concentration > 0.3), the peak position and shape of the CO fundamental are strongly influenced by "surface modes," while for lower concentrations the laboratory measured absorption spectra provide very accurate representations of the small particle extinction spectrum. The observed variations in peak position and width of the interstellar 2140 cm-1 component can be attributed to variations in composition and/or physical characteristics of the grains (i.e., shape). These observations show that many lines of sight contain (at least) two independent grain mantle components: a polar mixture (H2O-rich) responsible for the 3.08 and 6.0-mu-m ice bands and a nonpolar one dominating the solid CO spectrum. These two independent grain mantle components may reflect chemical variations during accretion. Around luminous protostars, differences in volatility of the nonpolar and H2O-rich ices also may play an important role in determining their relative abundances. C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. JOINT ASTRON CTR,HILO,HI 96720. RP TIELENS, AGGM (reprint author), NASA,AMES RES CTR,THEORET STUDIES BRANCH,MS 245-3,MOFFETT FIELD,CA 94035, USA. NR 67 TC 313 Z9 313 U1 2 U2 17 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1991 VL 381 IS 1 BP 181 EP 199 DI 10.1086/170640 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500018 PM 11538393 ER PT J AU WRIGHT, EL MATHER, JC BENNETT, CL CHENG, ES SHAFER, RA FIXSEN, DJ EPLEE, RE ISAACMAN, RB READ, SM BOGGESS, NW GULKIS, S HAUSER, MG JANSSEN, M KELSALL, T LUBIN, PM MEYER, SS MOSELEY, SH MURDOCK, TL SILVERBERG, RF SMOOT, GF WEISS, R WILKINSON, DT AF WRIGHT, EL MATHER, JC BENNETT, CL CHENG, ES SHAFER, RA FIXSEN, DJ EPLEE, RE ISAACMAN, RB READ, SM BOGGESS, NW GULKIS, S HAUSER, MG JANSSEN, M KELSALL, T LUBIN, PM MEYER, SS MOSELEY, SH MURDOCK, TL SILVERBERG, RF SMOOT, GF WEISS, R WILKINSON, DT TI PRELIMINARY SPECTRAL OBSERVATIONS OF THE GALAXY WITH A 7-DEGREES BEAM BY THE COSMIC BACKGROUND EXPLORER (COBE) SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SPECTRA; INTERSTELLAR, GRAINS; INTERSTELLAR, MATTER; INTERSTELLAR, MOLECULES ID C-II EMISSION; INTERSTELLAR-MEDIUM; MOLECULAR CLOUDS; GALACTIC PLANE; ATOMIC CARBON; 158 MICRON; LINE; REGIONS; DUST; TEMPERATURE AB The far-infrared absolute spectrophotometer (FIRAS) on the Cosmic Background Explorer (COBE) has carried out the first all-sky spectral line survey in the far-infrared region, as well as mapping spectra of the Galactic dust distribution at lambda > 100-mu-m. Lines of [C I], [C II], [N II], and CO are all clearly detected, [C II] (158-mu-m) and [N II] (205.3-mu-m) with sufficient strength to be mapped, and the wavelength of the [N II] line at 205.3-mu-m is determined by observation for the first time. The mean line intensities are interpreted in terms of the heating and cooling of the multiple phases of the interstellar gas. In addition, an average spectrum of the galaxy is constructed and searched for weak lines. The spectrum of the galaxy observed by FIRAS has two major components: a continuous spectrum due to interstellar dust heated by starlight with a total luminosity of (1.8 +/- 0.6)(R0/8.5 kpc)2 x 10(10) L. within the solar circle; and a line spectrum dominated by the strong 158-mu-m line from singly ionized carbon, with a spatial distribution similar to the dust distribution, and a luminosity of 0.3% of the dust luminosity. There are in addition moderately strong 122 and 205.3-mu-m lines, identified as coming from singly ionized nitrogen, which contribute 0.04% and 0.03% of the total dust luminosity. The much weaker lines of neutral carbon at 370 and 609-mu-m are seen, as are the 2-1 through 5-4 CO lines. These low-J CO lines contribute 0.003% of the total dust luminosity. Maps of the emission by dust, [C II], and [N II] are presented. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,GEN SCI CORP,GREENBELT,MD 20771. ST SYST CORP,LANHAM,MD 20706. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. GEN RES CORP,DANVERS,MA 01923. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,SSL,BERKELEY,CA 94720. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. RP WRIGHT, EL (reprint author), UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024, USA. RI Moseley, Harvey/D-5069-2012 NR 46 TC 350 Z9 350 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1991 VL 381 IS 1 BP 200 EP 209 DI 10.1086/170641 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500019 ER PT J AU ROELLIG, TL BECKLIN, EE JEFFERIES, JT KOPP, GA LINDSEY, CA ORRALL, FQ WERNER, MW AF ROELLIG, TL BECKLIN, EE JEFFERIES, JT KOPP, GA LINDSEY, CA ORRALL, FQ WERNER, MW TI SUBMILLIMETER SOLAR LIMB PROFILES DETERMINED FROM OBSERVATIONS OF THE TOTAL SOLAR ECLIPSE OF 1988 MARCH 18 SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, GENERAL; SUN, CHROMOSPHERE; SUN, ECLIPSES; SUN, LIMB DARKENING ID CHROMOSPHERE; SUN AB Observations were made of the extreme solar limb in six far-infrared wavelength bands ranging from 30 to 670-mu-m using the Kuiper Airborne Observatory during the total eclipse of the Sun on 1988 March 18. By observations of the occultation of the solar limb by the Moon, it was possible to obtain a spatial resolution of 0."5 normal to the limb. The results at wavelengths of 100-mu-m and less were found to be essentially equivalent to those obtained in 1986 by Lindsey et al., and we discuss here in detail only the results of the 200, 360, and 670-mu-m observations. The solar limb was found to be extended with respect to the visible limb at all of these wavelengths, with the extension increasing with wavelength. Limb brightening was observed to increase slightly with increasing wavelength, and no sign of a sharp emission spike at the extreme limb was found at any of these wavelengths. The observations can be well fitted by a chromospheric model incorporating cool dense spicules in the lower chromosphere. C1 NATL OPT ASTRON OBSERV, TUCSON, AZ 85726 USA. UNIV HAWAII, INST ASTRON, KANEOHE, HI 96744 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP NASA, AMES RES CTR, MS 245-6, MOFFETT FIELD, CA 94035 USA. NR 13 TC 13 Z9 13 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 NOV 1 PY 1991 VL 381 IS 1 BP 288 EP 294 DI 10.1086/170650 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500028 ER PT J AU DEAMICI, G BERSANELLI, M KOGUT, A LEVIN, S LIMON, M SMOOT, GF AF DEAMICI, G BERSANELLI, M KOGUT, A LEVIN, S LIMON, M SMOOT, GF TI THE TEMPERATURE OF THE COSMIC MICROWAVE BACKGROUND-RADIATION AT 3.8 GHZ - RESULTS OF A MEASUREMENT FROM THE SOUTH-POLE SITE SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC BACKGROUND RADIATION; EARTH, ATMOSPHERE ID SPECTRUM; WAVELENGTH AB As part of an international collaboration to measure the low-frequency spectrum of the cosmic microwave background (CMB) radiation, we have measured its temperature at a frequency of 3.8 GHz (7.9 cm wavelength), during the austral spring of 1989, obtaining a brightness temperature, T(CMB), of 2.64 +/- 0.07 K (68% confidence level). The new result is in agreement with our previous measurements at the same frequency obtained in 1986-88 from a very different site and has comparable error bars. Combining measurements from all years we obtain T(CMB) = 2.64 +/- 0.06 K. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. CNR, IFC, I-20133 MILAN, ITALY. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP UNIV CALIF BERKELEY, SPACE SCI LAB, M-S 50-232, BERKELEY, CA 94720 USA. NR 19 TC 27 Z9 27 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 NOV 1 PY 1991 VL 381 IS 1 BP 341 EP 347 DI 10.1086/170656 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM575 UT WOS:A1991GM57500034 ER PT J AU DAVILA, JM CHITRE, SM AF DAVILA, JM CHITRE, SM TI MAGNETOACOUSTIC HEATING OF THE SOLAR CHROMOSPHERE SO ASTROPHYSICAL JOURNAL LA English DT Article DE MAGNETIC FIELDS; PLASMAS; STARS, CHROMOSPHERES; SUN, CHROMOSPHERE; SUN, MAGNETIC FIELDS ID RESONANT ABSORPTION; MAGNETIC-FIELD; WAVES AB Long-period acoustic waves generated in the solar convection zone can propagate radially outward through the overlying atmosphere and get resonantly absorbed in the magnetic arches of the low-lying chromospheric canopy. The resulting Poynting and acoustic flux that enters the magnetic canopy in the network regions is demonstrated to be adequate to account for the observed chromospheric emission. C1 TATA INST FUNDAMENTAL RES,BOMBAY 400005,INDIA. RP DAVILA, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 22 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 1991 VL 381 IS 1 BP L31 EP L33 DI 10.1086/186189 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM577 UT WOS:A1991GM57700008 ER PT J AU LONG, KS BLAIR, WP DAVIDSEN, AF BOWERS, CW DIXON, WV DURRANCE, ST FELDMAN, PD HENRY, RC KRISS, GA KRUK, JW MOOS, HW VANCURA, O FERGUSON, HC KIMBLE, RA AF LONG, KS BLAIR, WP DAVIDSEN, AF BOWERS, CW DIXON, WV DURRANCE, ST FELDMAN, PD HENRY, RC KRISS, GA KRUK, JW MOOS, HW VANCURA, O FERGUSON, HC KIMBLE, RA TI SPECTROSCOPY OF Z-CAMELOPARDALIS IN OUTBURST WITH THE HOPKINS ULTRAVIOLET TELESCOPE SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, ACCRETION; STARS, BINARIES; STARS, DWARF NOVAE; STARS, INDIVIDUAL (Z-CAMELOPARDALIS); ULTRAVIOLET, SPECTRA ID CATACLYSMIC VARIABLES; DWARF NOVAE; IUE OBSERVATIONS; SPECTRA; WINDS; HYDRI AB The Hopkins Ultraviolet Telescope on board the Astro-1 shuttle mission was used to observe the 830-1850 angstrom spectrum of the cataclysmic variable Z Camelopardalis near the peak of a normal outburst. The observation reveals a rich absorption-line and continuum spectrum which peaks near 1050 angstrom at a flux of 5 x 10(-12) ergs cm-2 s-1 angstrom-1. In the sub-Ly-alpha region, some of the stronger absorption lines include S VI lambda-lambda, 933, 945, C III lambda-977, N III lambda-991, O VI lambda-lambda-1032, 1038, He II lambda-1085, P v lambda-lambda-1118, 1128, and C III lambda-1176. No emission is observed below the Lyman limit. The continuum spectrum resembles that of an optically thick accretion disk where the integrated spectrum is constructed by summing stellar model atmospheres. Similar models using summed blackbody spectra fail to approximate the observed continuum. C1 JOHNS HOPKINS UNIV,CTR ASTROPHYS SCI,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. UNIV CAMBRIDGE,OBSERVAT,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP LONG, KS (reprint author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA. RI Kruk, Jeffrey/G-4047-2012 NR 24 TC 19 Z9 19 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 NOV 1 PY 1991 VL 381 IS 1 BP L25 EP L29 DI 10.1086/186188 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM577 UT WOS:A1991GM57700007 ER PT J AU SADUN, AC SADUN, LA AF SADUN, AC SADUN, LA TI RELATIVISTIC DYNAMICS OF EXPANDING SOURCES SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article AB Given a relativistically expanding source, the transformation of the emission spectrum from the comoving frame of the source to the observer's frame is calculated. In particular, we deal with two special cases, that of a uniformly expanding sphere and that of a cylinder. In each case we consider a power-law spectrum with two distinct regions - the optically thick and thin parts - and transform those regions separately. The results are discussed, and a generalized procedure for transforming a spectrum of unspecified form is outlined. This procedure takes into account any bulk motion by the source as well as expansion. Finally, applications of this procedure to astrophysical sources are briefly discussed. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NYU,COURANT INST MATH SCI,NEW YORK,NY 10012. RP SADUN, AC (reprint author), AGNES SCOTT COLL,BRADLEY OBSERV,DECATUR,GA 30030, USA. NR 9 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 NOV PY 1991 VL 185 IS 1 BP 21 EP 36 DI 10.1007/BF00642703 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR129 UT WOS:A1991GR12900002 ER PT J AU MANNHEIM, PD KAZANAS, D AF MANNHEIM, PD KAZANAS, D TI PROBING THE HIGGS VACUUM WITH GENERAL-RELATIVITY SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article AB We show that the structure of the Higgs vacuum could be revealed in gravitational experiments which probe the Schwarzschild geometry to only one order in MG/r beyond that needed for the classical tests of general relativity. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP MANNHEIM, PD (reprint author), UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06268, USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PD NOV PY 1991 VL 185 IS 2 BP 167 EP 179 DI 10.1007/BF00643185 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR130 UT WOS:A1991GR13000001 ER PT J AU BAYARD, DS HADAEGH, FY YAM, Y SCHEID, RE METTLER, E MILMAN, MH AF BAYARD, DS HADAEGH, FY YAM, Y SCHEID, RE METTLER, E MILMAN, MH TI AUTOMATED ON-ORBIT FREQUENCY-DOMAIN IDENTIFICATION FOR LARGE SPACE STRUCTURES SO AUTOMATICA LA English DT Article DE SPACE VEHICLES; ONLINE OPERATION; AEROSPACE CONTROL; FLEXIBLE STRUCTURES; LABORATORY TECHNIQUES; PARAMETER ESTIMATION; SYSTEM IDENTIFICATION; ROBUST CONTROL ID DESIGN AB Recent experiences in the field of flexible structure control in space have indicated a need for on-orbit system identification to support robust control redesign to avoid in-flight instabilities and maintain high spacecraft performance. This paper highlights an automated frequency domain system identification methodology recently developed to fulfill this need. The methodology is focused to support (1) the estimation of system quantities useful for robust control analysis and design, (2) experiment design tailored to performing system identification in a typically constrained on-orbit environment and (3) the automation of operations to reduce "human in the loop" requirements. A basic overview of the methodology is presented first, followed by an experimental verification of the approach performed on the JPL/AFAL test-bed facility. RP BAYARD, DS (reprint author), CALTECH,JET PROP LAB,GUIDANCE & CONTROL SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 39 TC 20 Z9 21 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0005-1098 J9 AUTOMATICA JI Automatica PD NOV PY 1991 VL 27 IS 6 BP 931 EP 946 DI 10.1016/0005-1098(91)90129-P PG 16 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA GT957 UT WOS:A1991GT95700003 ER PT J AU GANDER, PH MACDONALD, JA MONTGOMERY, JC PAULIN, MG AF GANDER, PH MACDONALD, JA MONTGOMERY, JC PAULIN, MG TI ADAPTATION OF SLEEP AND CIRCADIAN-RHYTHMS TO THE ANTARCTIC SUMMER - A QUESTION OF ZEITGEBER STRENGTH SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID PATTERNS; TEMPERATURE; CORTISOL AB Adaptation of sleep and circadian rhythms was examined in three temperate zone dwellers arriving in Antarctica during summer. Rectal temperature, wrist activity, and heart rate were monitored continuously, sleep timing and quality noted on awakening, and mood and fatigue rated every 2 h while awake. Sleep was poorer in 2/3 subjects in Antarctica, where all subjects reported more difficulty rising. Sleep occurred at the same clock times in New Zealand and Antarctica, however, the rhythms of temperature, activity, and heart rate underwent a delay of about 2 h. The subject with the most Antarctic experience had the least difficulty adapting to sleeping during constant daylight. The subject with the most delayed circadian rhythms had the most difficulty. The delay in the circadian system with respect to sleep and clock time is hypothesized to be due to differences in zeitgeber strength and/or zeitgeber exposure between Antarctica and New Zealand. C1 UNIV AUCKLAND,DEPT ZOOL,AUCKLAND,NEW ZEALAND. UNIV OTAGO,DEPT ZOOL,DUNEDIN,NEW ZEALAND. RP GANDER, PH (reprint author), NASA,AMES RES CTR,SAN JOSE STATE UNIV FDN,MOFFETT FIELD,CA 94035, USA. RI Montgomery, John/D-4310-2009 OI Montgomery, John/0000-0002-7451-3541 NR 26 TC 13 Z9 13 U1 0 U2 4 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 NOV PY 1991 VL 62 IS 11 BP 1019 EP 1025 PG 7 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA GM888 UT WOS:A1991GM88800001 PM 1741714 ER PT J AU KUSTAS, WP GOODRICH, DC MORAN, MS AMER, SA BACH, LB BLANFORD, JH CHEHBOUNI, A CLAASSEN, H CLEMENTS, WE DORAISWAMY, PC DUBOIS, P CLARKE, TR DAUGHTRY, CST GELLMAN, DI GRANT, TA HIPPS, LE HUETE, AR HUMES, KS JACKSON, TJ KEEFER, TO NICHOLS, WD PARRY, R PERRY, EM PINKER, RT PINTER, PJ QI, J RIGGS, AC SCHMUGGE, TJ SHUTKO, AM STANNARD, DI SWIATEK, E VANLEEUWEN, JD VANZYL, J VIDAL, A WASHBURNE, J WELTZ, MA AF KUSTAS, WP GOODRICH, DC MORAN, MS AMER, SA BACH, LB BLANFORD, JH CHEHBOUNI, A CLAASSEN, H CLEMENTS, WE DORAISWAMY, PC DUBOIS, P CLARKE, TR DAUGHTRY, CST GELLMAN, DI GRANT, TA HIPPS, LE HUETE, AR HUMES, KS JACKSON, TJ KEEFER, TO NICHOLS, WD PARRY, R PERRY, EM PINKER, RT PINTER, PJ QI, J RIGGS, AC SCHMUGGE, TJ SHUTKO, AM STANNARD, DI SWIATEK, E VANLEEUWEN, JD VANZYL, J VIDAL, A WASHBURNE, J WELTZ, MA TI AN INTERDISCIPLINARY FIELD-STUDY OF THE ENERGY AND WATER FLUXES IN THE ATMOSPHERE-BIOSPHERE SYSTEM OVER SEMIARID RANGELANDS - DESCRIPTION AND SOME PRELIMINARY-RESULTS SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SOUTHWESTERN UNITED-STATES; SOIL-MOISTURE; METEOROLOGICAL DATA; RADIATION BUDGET; EDDY-CORRELATION; BOUNDARY-LAYER; EVAPOTRANSPIRATION; RAINFALL; EVAPORATION; BALANCE AB Arid and semiarid rangelands comprise a significant portion of the earth's land surface. Yet little is known about the effects of temporal and spatial changes in surface soil moisture on the hydrologic cycle, energy balance, and the feedbacks to the atmosphere via thermal forcing over such environments. Understanding this interrelationship is crucial for evaluating the role of the hydrologic cycle in surface-atmosphere interactions. This study focuses on the utility of remote sensing to provide measurements of surface soil moisture, surface albedo, vegetation biomass, and temperature at different spatial and temporal scales. Remote-sensing measurements may provide the only practical means of estimating some of the more important factors controlling land surface processes over large areas. Consequently, the use of remotely sensed information in biophysical and geophysical models greatly enhances their ability to compute fluxes at catchment and regional scales on a routine basis. However, model calculations for different climates and ecosystems need verification. This requires that the remotely sensed data and model computations be evaluated with ground-truth data collected at the same areal scales. The present study (MONSOON 90) attempts to address this issue for semiarid rangelands. The experimental plan included remotely sensed data in the visible, near-infrared, thermal, and microwave wavelengths from ground and aircraft platforms and, when available, from satellites. Collected concurrently were ground measurements of soil moisture and temperature, energy and water fluxes, and profile data in the atmospheric boundary layer in a hydrologically instrumented semiarid rangeland watershed. Field experiments were conducted in 1990 during the dry and wet or "monsoon season" for the southwestern United States. A detailed description of the field campaigns, including measurements and some preliminary results are given. C1 USDA ARS,US WATER CONSERVAT LAB,PHOENIX,AZ 85040. USDA ARS,ARIDLAND WATERSHED MANAGEMENT RES UNIT,TUCSON,AZ. USDA ARS,BELTSVILLE AGR RES CTR,REMOTE SENSING RES LAB,BELTSVILLE,MD 20705. CEMAGREF,ENGREF,REMOTE SENSING LAB,MONTPELLIER,FRANCE. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. UNIV ARIZONA,DEPT OPT SCI,TUCSON,AZ 85721. US GEOL SURVEY,DIV WATER RESOURCES,DENVER,CO 80225. UTAH STATE UNIV,DEPT SOIL SCI & BIOMETEOROL,LOGAN,UT 84322. UNIV ARIZONA,SCH RENEWABLE NAT RESOURCES,TUCSON,AZ 85721. ACAD SCI USSR,INST RADIOENGN & ELECTR,MOSCOW V-71,USSR. US GEOL SURVEY,DIV WATER RESOURCES,CARSON,NV. UNIV MARYLAND,DEPT METEOROL,COLLEGE PK,MD 20742. UNIV ARIZONA,DEPT SOIL & WATER SCI,TUCSON,AZ 85721. UNIV ARIZONA,DEPT HYDROL & WATER RESOURCES,TUCSON,AZ 85721. ETUDES & RECH TELEDETECT SPATIALE,TOULOUSE,FRANCE. RP KUSTAS, WP (reprint author), USDA ARS,BELTSVILLE AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705, USA. RI Vidal, Alain/A-3986-2009; Pinker, Rachel/F-6565-2010; Dubois-Fernandez, Pascale/A-6743-2012; Goodrich, David/B-1763-2009 OI Goodrich, David/0000-0001-7735-1448 NR 72 TC 77 Z9 80 U1 0 U2 12 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 NOV PY 1991 VL 72 IS 11 BP 1683 EP 1705 DI 10.1175/1520-0477(1991)072<1683:AIFSOT>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GR433 UT WOS:A1991GR43300001 ER PT J AU BUCHER, UJ MAST, FW BISCHOF, N AF BUCHER, UJ MAST, FW BISCHOF, N TI DISTORTIONS IN THE PERCEPTION OF SPATIAL AXES SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV ZURICH,CH-8006 ZURICH,SWITZERLAND. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 487 EP 487 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500162 ER PT J AU CUNNINGHAM, HA WELCH, RB AF CUNNINGHAM, HA WELCH, RB TI GENERALIZATION BETWEEN SENSORIMOTOR MAPS SO BULLETIN OF THE PSYCHONOMIC 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 PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 488 EP 488 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500170 ER PT J AU MCBEATH, MK AF MCBEATH, MK TI INFLUENCE OF DEPTH CUES ON VELOCITY OF APPARENT MOTION SO BULLETIN OF THE PSYCHONOMIC 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 PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 488 EP 488 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500173 ER PT J AU SCHIANO, DJ MCBEATH, MK TVERSKY, B AF SCHIANO, DJ MCBEATH, MK TVERSKY, B TI 3-D BILATERAL SYMMETRY ASSUMED IN JUDGING FIGURAL IDENTITY AND ORIENTATION SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,NRC,MOFFETT FIELD,CA 94035. STANFORD UNIV,STANFORD,CA 94305. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 488 EP 488 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500176 ER PT J AU NEMIRE, K ELLIS, SR AF NEMIRE, K ELLIS, SR TI OPTIC BIAS OF PERCEIVED EYE LEVEL DEPENDS ON STRUCTURE OF THE OPTIC ARRAY SO BULLETIN OF THE PSYCHONOMIC 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 PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 501 EP 501 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500311 ER PT J AU SHIFFRAR, M MULLIGAN, JB AF SHIFFRAR, M MULLIGAN, JB TI A TEST FOR MODELS OF MOTION PROCESSING - NONRIGIDLY PERCEIVED ROTATING ELLIPSES SO BULLETIN OF THE PSYCHONOMIC 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 PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 502 EP 502 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500320 ER PT J AU FOLK, CL JOHNSTON, JC REMINGTON, RW AF FOLK, CL JOHNSTON, JC REMINGTON, RW TI INVOLUNTARY CAPTURE OF SPATIAL ATTENTION IS CONTINGENT ON CONTROL SETTINGS SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. VILLANOVA UNIV,VILLANOVA,PA 19085. RI Martin Arevalo, Elisa/L-4472-2014 OI Martin Arevalo, Elisa/0000-0002-4546-6440 NR 0 TC 1 Z9 1 U1 1 U2 1 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 514 EP 514 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500460 ER PT J AU MCCANN, RS FOLK, CL REMINGTON, RW AF MCCANN, RS FOLK, CL REMINGTON, RW TI THE ROLE OF STRATEGIES IN CHOICE REACTION-TIME TASKS SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 VILLANOVA UNIV,VILLANOVA,PA 19085. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 517 EP 518 PG 2 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500487 ER PT J AU FOYLE, DC MCCANN, RS SANFORD, BD AF FOYLE, DC MCCANN, RS SANFORD, BD TI SUPERIMPOSED INFORMATION DISPLAYS - ATTENTIONAL DEFICITS AND POTENTIAL SOLUTIONS SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. STERLING FED SYST,PALO ALTO,CA. SAN JOSE STATE UNIV,SAN JOSE,CA 95192. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 518 EP 518 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500495 ER PT J AU HANNA, A REMINGTON, RW AF HANNA, A REMINGTON, RW TI THE REPRESENTATION OF COLOR AND FORM IN MEMORY SO BULLETIN OF THE PSYCHONOMIC 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 PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 520 EP 520 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500522 ER PT J AU ELLIS, SR TYLER, M KIM, WS AF ELLIS, SR TYLER, M KIM, WS TI SEPARABLE COMPONENTS OF 3-D TRACKING WITH MISALIGNMENT BETWEEN DISPLAY AND CONTROL AXIS SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF BERKELEY,BERKELEY,CA 94720. CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 525 EP 525 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500569 ER PT J AU WELCH, RB BRIDGEMAN, B ANAND, S BROWMAN, K AF WELCH, RB BRIDGEMAN, B ANAND, S BROWMAN, K TI THE ACQUISITION OF DUAL ADAPTATIONS AND ADAPTATION SETS SO BULLETIN OF THE PSYCHONOMIC SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0090-5054 J9 B PSYCHONOMIC SOC PD NOV PY 1991 VL 29 IS 6 BP 530 EP 530 PG 1 WC Psychology, Mathematical SC Psychology GA GL115 UT WOS:A1991GL11500626 ER PT J AU NOEVER, DA AF NOEVER, DA TI STATISTICS OF CONTRACTIVE CRACKING PATTERNS SO CANADIAN JOURNAL OF PHYSICS LA English DT Article ID SOILS; MODEL AB The statistics of convective soil patterns are analyzed using statistical crystallography. A underlying hierarchy of order is found to span four orders of magnitude in characteristic pattern length. Strict mathematical requirements determine the two-dimensional (2D) topology, such that random partitioning of space yields a predictable statistical geometry for polygons. For all lengths, Aboav's and Lewis's laws are verified; this result is consistent both with the need to fill 2D space and most significantly with energy carried not by the patterns' interior, but by the boundaries. Together, this suggests a common mechanism of formation for both micro- and macro-freezing patterns. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES-76,HUNTSVILLE,AL 35812, USA. NR 16 TC 2 Z9 2 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD NOV PY 1991 VL 69 IS 11 BP 1338 EP 1341 PG 4 WC Physics, Multidisciplinary SC Physics GA HC556 UT WOS:A1991HC55600005 ER PT J AU FRIMPONG, S PLANK, CA LAUKHUF, WLS AF FRIMPONG, S PLANK, CA LAUKHUF, WLS TI SORPTION AND TRANSPORT OF SULFUR-DIOXIDE IN POLYCARBONATE POLYARYLATE BLENDS SO CHEMICAL ENGINEERING JOURNAL AND THE BIOCHEMICAL ENGINEERING JOURNAL LA English DT Article ID POLY(VINYLIDENE FLUORIDE); GLASSY-POLYMERS; MISCIBILITY; POLYESTER; BEHAVIOR; GASES AB Blends of polycarbonate and polyarylate were prepared and characterized by differential scanning calorimetry and a dynamic mechanical measurements technique. Blends of 40% polyarylate and above were found to have two glass transition temperatures suggesting immiscibility. Sorption and transport measurements were made at 25-degrees-C and up to approximately atmospheric pressure on these blends using sulfur dioxide as the penetrant. All the obtained data are described well with the dual sorption dual-mobility models developed for a gas-glassy-polymer system. The sorption and transport parameters deduced experimentally from this system were correlated with blend composition. The diffusion coefficient data are interpreted in terms of the partial immobilization model. C1 UNIV LOUISVILLE,DEPT CHEM ENGN,LOUISVILLE,KY 40292. RP FRIMPONG, S (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 26 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 0923-0467 J9 CHEM ENG J BIOCH ENG JI Chem. Eng. J. Biochem. Eng. J. PD NOV PY 1991 VL 47 IS 2 BP 63 EP 73 DI 10.1016/0300-9467(91)85009-K PG 11 WC Engineering, Chemical SC Engineering GA GU596 UT WOS:A1991GU59600001 ER PT J AU SALERNO, LJ SPIVAK, AL KITTEL, P AF SALERNO, LJ SPIVAK, AL KITTEL, P TI PERFORMANCE OF ALL-METAL DEMOUNTABLE CRYOGENIC SEALS AT SUPERFLUID-HELIUM TEMPERATURES SO CRYOGENICS LA English DT Note DE HELIUM; LEAKS; SEALS AB Two all-metal demountable cryogenic seals with an outside diameter of 36.6 mm, inside diameter of 27.2 mm and thickness of 0.51 mm were leak tested at room temperature (300 K), liquid nitrogen temperature (21 cycles at 77 K), liquid helium temperature (nine cycles at 4.2 K) and superfluid helium temperature (four cycles at 1.6 K). Each seal was mounted and demounted for 13 cycles. Thickness measurements at 90-degrees intervals along the circumference showed a maximum seal compression of 0.038 mm. Leak rate measurements at all temperatures showed no detectable leak above the helium background level, typically 0.1 x 10(-9) std cm3 s-1, during testing. C1 TRANS BAY ELECTR,RICHMOND,CA 94804. RP SALERNO, LJ (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 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 NOV PY 1991 VL 31 IS 11 BP 993 EP 995 DI 10.1016/0011-2275(91)90226-M PG 3 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA GL149 UT WOS:A1991GL14900012 ER PT J AU SENSKE, DA CAMPBELL, DB HEAD, JW FISHER, PC HINE, AA DECHARON, A FRANK, SL KEDDIE, ST ROBERTS, KM STOFAN, ER AUBELE, JC CRUMPLER, LS STACY, N AF SENSKE, DA CAMPBELL, DB HEAD, JW FISHER, PC HINE, AA DECHARON, A FRANK, SL KEDDIE, ST ROBERTS, KM STOFAN, ER AUBELE, JC CRUMPLER, LS STACY, N TI GEOLOGY AND TECTONICS OF THE THEMIS REGIO-LAVINIA PLANITIA-ALPHA REGIO-LADA TERRA AREA, VENUS - RESULTS FROM ARECIBO IMAGE DATA SO EARTH MOON AND PLANETS LA English DT Article ID BETA-REGIO; SURFACE-FEATURES; IMPACT CRATERS; RADAR; VENERA-15; VOLCANISM; RIFT; REFLECTIVITY; CONSTRAINTS; MORPHOLOGY AB New radar images obtained from the Arecibo Observatory (resolution 1.5-4.0 km) for portions of the southern hemisphere of Venus show that: the upland of Phoebe Regio contains the southern extension of Devana Chasma, a rift zone extending 4200 km south from Theia Mons and interpreted as a zone of extension; Alpha Regio, the only large region of tessera within the imaged area, is similar to tessera mapped elsewhere on the planet and covers a smaller percentage of the surface than that observed in the northern high latitudes; the upland made of Ushas, Innini and Hathor Montes consists of three distinct volcanic constructs; Themis Regio is mapped as an ovoid chain of radar-bright arcuate single and double ring structures, edifices and bright lineaments. This area is interpreted as a region of mantle upwelling and on the basis of apparent split and separated features, a zone of localized faulting and extension. Linear zones of deformation in Lavinia Planitia are characterized by lineament belts that are often locally elevated, are similar to ridge belts mapped in the northern high latitudes and are interpreted to be characterized mainly by compression; radar-bright lava complexes within Lavinia Planitia are unique to this part of the planet and are interpreted to represent areas of eruption of high volumes of extremely fluid lava; the upland of Lada Terra is bound to the north by a linear deformation zone interpreted as extensional, is characterized by large ovoids and coronae, is interpreted to be associated with an area of mantle upwelling, and is in contrast to the northern high latitude highland of Ishtar Terra. Regions of plains in the southern hemisphere cover about 78% of the mapped area and are interpreted to be volcanic in origin. Located within the area imaged (10-78-degrees-S) are 52 craters interpreted to be of impact origin ranging from 8 to 157 km in diameter. On the basis of an overall crater density of 0.94 craters/10(6) km2, it is determined that the age of this part of the Venus surface is similar to the 0.3 to 1.0 billion year age calculated for the equatorial region and northern high latitudes. The geologic characteristics of the portion of the Venus southern hemisphere imaged by Arecibo are generally similar to those mapped elsewhere on the planet. This part of the planet is characterized by widespread volcanic plains, large volcanic edifices, and zones of linear belt deformation. The southern hemisphere of Venus differs from northern high latitudes in that tessera makes up only a small percentage of the surface area and the ovoid chain in Themis Regio is unique to this part of the planet. On the basis of the analysis presented here, the southern hemisphere of Venus is interpreted to be characterized by regions of mantle upwelling on a variety of scales (ovoids, region made up of Ushas, Innini and Hathor Montes), upwelling and extension (Themis Regio) and localized compression (lineament belts in Lavinia Planitia). C1 CORNELL UNIV,NATL ASTRON & IONOSPHERE CTR,ITHACA,NY 14853. ARECIBO OBSERV,NATL ASTRON & IONOSPHERE CTR,ARECIBO,PR 00612. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP SENSKE, DA (reprint author), BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912, USA. NR 75 TC 17 Z9 17 U1 0 U2 1 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 NOV PY 1991 VL 55 IS 2 BP 97 EP 161 DI 10.1007/BF00058900 PG 65 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA GW310 UT WOS:A1991GW31000001 ER PT J AU SENSKE, DA CAMPBELL, DB STOFAN, ER FISHER, PC HEAD, JW STACY, N AUBELE, JC HINE, AA HARMON, JK AF SENSKE, DA CAMPBELL, DB STOFAN, ER FISHER, PC HEAD, JW STACY, N AUBELE, JC HINE, AA HARMON, JK TI GEOLOGY AND TECTONICS OF BETA-REGIO, GUINEVERE PLANITIA, SEDNA PLANITIA, AND WESTERN EISTLA REGIO, VENUS - RESULTS FROM ARECIBO IMAGE DATA SO EARTH MOON AND PLANETS LA English DT Article ID ISHTAR-TERRA; RADAR DATA; SURFACE; VOLCANISM; ORIGIN; REFLECTIVITY; MORPHOLOGY; VENERA-15; ROUGHNESS; LANDFORMS AB New radar images (resolution 1.5-2.0 km) obtained from the Arecibo Observatory are used to assess the geology of a portion of the equatorial region of Venus (1-degrees-S to 45-degrees-N and from 270-degrees eastward to 30-degrees). Nine geologic units are mapped on the basis of their radar characteristics and their distribution and correspondences with topography are examined. Plains are the most abundant unit, make up 80% of the area imaged, and are divided into bright, dark, and mottled. Mottled plains contain abundant lava flows and domes suggesting that volcanism forming plains is a significant process in the equatorial region of Venus. Tesserae are found primarily on Beta Regio and its eastern flank and are interpreted to be locally stratigraphically older units, predating episodes of faulting and plains formation. Isolated regions of tesserae concentrated to the north of Western Eistla Regio are interpreted to predate the formation of plains in this area. The volcanoes Sif Mons, Gula Mons, Sappho, Theia Mons, and Rhea Mons, are found exclusively in highland regions and their deposits are interpreted as contributing only a small percentage to the overall volume of the regional topography. The northern 15-degrees of the image data overlap with Venera 15/16 images making it possible to examine the characteristics of geologic units mapped under various illumination directions and incidence angles. Surface panoramas and geochemical data obtained from Venera landers provide ground truth for map units, evidence that plains are made up of basaltic lava flows, and that linear deformation zones contain abundant blocks and cobbles. On the basis of spatial and temporal relationships between geologic units, the highlands of Beta Regio and Western Eistla Regio are interpreted to have formed in association with areas of mantle upwelling which uplift plains, cause rifting, and in the case of Beta Regio, disrupt a large region of tessera. Zones of linear belt deformation in Beta Regio and Western Eistla Regio are interpreted to be extensional and indicate that at least limited extension has occurred in both regions. The images reveal for the first time that southern Devana Chasma is a region of overlapping rift valleys separated by a distance of 600 km. Linear deformation zones in Guinevere Planitia, separating Beta Regio and Eistla Regio, converge at a region of ovoids forming a discontinuous zone of disruption and completes an equatorial encompassing network of highlands and tectonic features. The similarity between ovoids and coronae suggests a mechanism of formation associated with hotspots or mantle plumes. Analysis of the distribution and density of impact craters suggests a surface age for this part of the planet similar to or slightly less than that determined for the northern high latitudes from Venera 15/16 data (0.3 to 1.5 by) and comparable to that calculated for the southern hemisphere. C1 CORNELL UNIV,NATL ASTRON & IONOSPHERE CTR,ITHACA,NY 14853. CALTECH,JET PROP LAB,PASADENA,CA 91109. ARECIBO OBSERV,NATL ASTRON & IONOSPHERE CTR,ARECIBO,PR 00612. RP SENSKE, DA (reprint author), BROWN UNIV,DEPT GEOL,PROVIDENCE,RI 02912, USA. NR 51 TC 12 Z9 12 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD NOV PY 1991 VL 55 IS 2 BP 163 EP 214 DI 10.1007/BF00058901 PG 52 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA GW310 UT WOS:A1991GW31000002 ER PT J AU LYNN, BH CARLSON, TN AF LYNN, BH CARLSON, TN TI SIMULATING TRANSPIRATION PLATEAUS - THE IMPORTANCE OF LEAF WATER POTENTIAL SO ECOLOGICAL MODELLING LA English DT Article ID STOMATAL CONDUCTANCE; FIELD CONDITIONS; PLANT; RESISTANCE; MODEL; WHEAT; EVAPOTRANSPIRATION; FOREST; CORN; OAK AB Two different bulk stomatal resistance models are compared with measurements of evapotranspiration. We show that a transpiration plateau is more realistically simulated by relating stomatal resistance to leaf water potential, rather than directly to the soil water potential and the leaf vapor pressure difference. C1 RUTGERS STATE UNIV,COOK COLL,DEPT METEOROL & PHYS OCEANOG,NEW BRUNSWICK,NJ 08903. PENN STATE UNIV,DEPT METEOROL,UNIV PK,PA 16802. RP LYNN, BH (reprint author), GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 22 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD NOV PY 1991 VL 58 IS 1-4 BP 199 EP 208 DI 10.1016/0304-3800(91)90036-Z PG 10 WC Ecology SC Environmental Sciences & Ecology GA GV242 UT WOS:A1991GV24200009 ER PT J AU CURLANDER, JC CHANG, CY AF CURLANDER, JC CHANG, CY TI TECHNIQUES IN PROCESSING MULTIFREQUENCY MULTI-POLARIZATION SPACEBORNE SAR DATA SO EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS LA English DT Article AB This paper presents the algorithm design of the SIR-C ground data processor, with emphasis on the unique elements involved in the production of registered multi-frequency polarimetric data products. A quick-look processing algorithm used for generation of low-resolution browse image products and estimation of echo signal parameters is also presented. Specifically, we will discuss the following: 1) Azimuth reference function generation to produce registered polarimetric imagery; 2) Geometric rectification to accommodate cross-track and along-track Doppler drifts; 3) Multi-look filtering designed to generate output imagery with a uniform resolution; and 4): Efficient coding to compress the polarimetric image data for distribution. RP CURLANDER, JC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC ELETTROTECNICA ED ELETTRONICA ITALIANA PI MILAN PA VIALE MONZA 259, 20126 MILAN, ITALY SN 1120-3862 J9 EUR T TELECOMMUN JI Eur. Trans. Telecomm. PD NOV-DEC PY 1991 VL 2 IS 6 BP 605 EP 617 DI 10.1002/ett.4460020603 PG 13 WC Telecommunications SC Telecommunications GA HC153 UT WOS:A1991HC15300002 ER PT J AU LINDSTROM, MM SCHWARZ, C SCORE, R MASON, B AF LINDSTROM, MM SCHWARZ, C SCORE, R MASON, B TI MACALPINE HILLS-88104 AND HILLS-88105 LUNAR HIGHLAND METEORITES - GENERAL DESCRIPTION AND CONSORTIUM OVERVIEW SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT SPECIAL SESSION OF THE 21ST LUNAR AND PLANETARY SCIENCE CONF : THE MACALPINE HILLS LUNAR METEORITE CONSORTIUM CY MAR 12, 1990 CL HOUSTON, TX ID HISTORY AB MacAlpine Hills 88104 and 88105 are new lunar meteorites returned from Antarctica by the 1988-1989 US meteorite collection team. The two specimens were found in nearby locations and, based on field and laboratory evidence, are though to be pieces of the same meteorite. MAC88105 is the largest lunar meteorite yet found (662 g). MAC88104/5 is an anorthositic breccia consisting of numerous small clasts in a glassy matrix. An origin on the Moon is supported by the mineral, bulk, and oxygen isotope compositions. A consortium of twenty research groups has studied these meteorites. Samples were prepared at the NASA Johnson Space Center meteorite processing laboratory. Details of consortium plans and allocations are documented herein. A summary list of lunar meteorites and an overview of consortium research is presented. Discussions in this and the following consortium papers involve the issue of paired meteorites and paired ejecta, and what new information about the nature and evolution of the lunar crust is provided by the lunar meteorites. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NATL MUSEUM NAT HIST,WASHINGTON,DC 20560. RP LINDSTROM, MM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN2,HOUSTON,TX 77058, USA. NR 30 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD NOV PY 1991 VL 55 IS 11 BP 2999 EP 3007 DI 10.1016/0016-7037(91)90468-K PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GT024 UT WOS:A1991GT02400001 ER PT J AU LINDSTROM, MM WENTWORTH, SJ MARTINEZ, RR MITTLEFEHLDT, DW MCKAY, DS WANG, MS LIPSCHUTZ, ME AF LINDSTROM, MM WENTWORTH, SJ MARTINEZ, RR MITTLEFEHLDT, DW MCKAY, DS WANG, MS LIPSCHUTZ, ME TI GEOCHEMISTRY AND PETROGRAPHY OF THE MACALPINE HILLS LUNAR METEORITES SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT SPECIAL SESSION OF THE 21ST LUNAR AND PLANETARY SCIENCE CONF : THE MACALPINE HILLS LUNAR METEORITE CONSORTIUM CY MAR 12, 1990 CL HOUSTON, TX ID NEUTRON-ACTIVATION ANALYSIS; ALHA81005; ELEMENTS AB MacAlpine Hills 88104 and 88105 are anorthositic lunar meteorites recovered from the same area in Antarctica which are demonstrated to be paired samples of the same fall. Petrographic studies of matrix and clasts show that MAC88104/5 is a polymict breccia dominated by impact melt clasts. It contains a small amount of highland impact glass and very few regolith glass spherules. It is better classified as a fragmental breccia than a regolith breccia. The bulk composition is ferroan (mg' = 63) and highly aluminous (Al2O3 = 28%). REE and other incompatible element concentrations are very low. Compositions of anorthositic, granulitic, and impact melt breccia clasts are very similar to, but distinct from, matrix composition. MAC88104/5 is very similar in composition to the other anorthositic lunar meteorites, but each of the meteorites is distinct. The anorthositic lunar meteorites, especially MAC88104/5 and Y82192/3/86032, are very similar to North Ray Crater feldspathic fragmental breccias in composition and petrography. These fragmental lunar meteorites may have been ancient, deeply buried breccias from the megaregolith. Comparisons of chemical-petrographic features and exposure histories suggest that the twelve lunar meteorites were derived from two to nine, but probably four to seven, impacts onto the lunar surface. Discrepancies between the proportions of lunar meteorites and results of Apollo missions may be due to unrepresentative sampling. Lunar meteorites provide valuable new information on the nature of the lunar crust. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. RP LINDSTROM, MM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN2,HOUSTON,TX 77058, USA. NR 53 TC 23 Z9 23 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 NOV PY 1991 VL 55 IS 11 BP 3089 EP 3103 DI 10.1016/0016-7037(91)90475-K PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GT024 UT WOS:A1991GT02400008 ER PT J AU SHILLER, AM BOYLE, EA AF SHILLER, AM BOYLE, EA TI TRACE-ELEMENTS IN THE MISSISSIPPI RIVER-DELTA OUTFLOW REGION - BEHAVIOR AT HIGH DISCHARGE SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT SPECIAL SESSION OF THE 21ST LUNAR AND PLANETARY SCIENCE CONF : THE MACALPINE HILLS LUNAR METEORITE CONSORTIUM CY MAR 12, 1990 CL HOUSTON, TX ID CHEMICAL MASS-BALANCE; NORTH PACIFIC-OCEAN; DISSOLVED MOLYBDENUM; ESTUARIES; WATERS; VANADIUM; COPPER; CHROMIUM; DYNAMICS; CADMIUM AB Samples for dissolved trace element analysis were collected in surface waters of the plume of the Mississippi River during a period of high river discharge. These field data are compared with results of laboratory mixing experiments. The studies show that Cu, Ni, and Mo are largely unreactive in the plume. Surprisingly, Fe also appears to show little reactivity; the pronounced flocculation removal of Fe frequently observed in other estuaries is not seen in this system. This difference may be a consequence of the alkaline nature of the Mississippi which results in low dissolved Fe concentrations in the river (<50 nmol/kg). Zinc, another particle-reactive element, also shows little reactivity. This lack of reactivity for Zn, as well as Cu and Ni, is partly a result of the short residence time of plume waters in shallow areas affected by sedimentary interactions. The chromium distribution shows apparent non-conservative behavior indicative of estuarine removal; however, temporal variation in river concentrations is a more likely explanation for this behavior. For some other elements, complex distributions occur as a consequence of the interplay of physical-chemical and/or biological processes with the dynamic mixing regime. For Cd, desorption from the suspended load plays a major role in determining the distribution. However, sedimentary input may also play a role in the spatial variability of Cd. For V, biological uptake in the plume exerts a strong influence on its distribution. At the time of this study, uptake was large enough to consume both the river flux of V as well as a substantial amount of vanadium supplied by the ocean. C1 MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. RP SHILLER, AM (reprint author), UNIV SO MISSISSIPPI,STENNIS SPACE CTR,CTR MARINE SCI,HATTIESBURG,MS 39406, USA. OI Shiller, Alan/0000-0002-2068-7909 NR 45 TC 100 Z9 102 U1 0 U2 8 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 NOV PY 1991 VL 55 IS 11 BP 3241 EP 3251 DI 10.1016/0016-7037(91)90486-O PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GT024 UT WOS:A1991GT02400019 ER PT J AU MERRITTS, DJ CHADWICK, OA HENDRICKS, DM AF MERRITTS, DJ CHADWICK, OA HENDRICKS, DM TI RATES AND PROCESSES OF SOIL EVOLUTION ON UPLIFTED MARINE TERRACES, NORTHERN CALIFORNIA SO GEODERMA LA English DT Article; Proceedings Paper CT SYMP ON WEATHERING AND SOILS CY JUL 09-19, 1989 CL WASHINGTON, DC ID SEA-LEVEL; NEW-ZEALAND; NEW-GUINEA; ALUMINUM; AGE AB Time-dependent changes in soil development have been evaluated for two flights of uplifted marine terraces with similar site characteristics and a range in terrace ages (approximately 3.9 ka to 330 ka) in northern California. Six pedogenic properties of soils developed in unconsolidated deposits overlying bedrock marine platforms have systematic, time-dependent trends, but each property differs in rate of change and in the time period over which its changes are useful as relative age dating or correlation tools. Changes in accumulated mass of organic carbon and pH are useful properties only for the youngest soils, and probably for soils less than 10-20 ka in this climatic region. Soils on terraces older than 29 ka have nearly similar amounts of mass of organic carbon, with values of about 3-6% by weight for the upper meter of the soil profile. Soil reaction (pH) in the top 20 cm of the soil profile decreases at a rapidly declining rate, reaching and maintaining a value of approximately 5 by 29-40 ka. Total mass of accumulated clay is an excellent indicator of relative soil age during all stages of soil development. The rate of accumulation of clay is about 0.4 g/cm 2 Soil column per thousand years, so that pedons on terraces with inferred ages of about 124 ka have accumulated at least 50 g/cm2 soil column of clay. Systematic and linear increases in accumulated mass of several forms of pedogenic iron make them very useful for chronological purposes for at least 240 ky of soil development. Crystalline forms of iron enable greater distinction among young soils than amorphous forms, which have negligible accumulations until at least 40 ka. The rate of accumulation of crystalline forms of iron (Fe(d)-Fe(o)) is about 0.02 g/cm2 soil column per thousand years, so that pedons on terraces with inferred ages of about 124 ka have accumulated about 3 g/cm2 soil column of crystalline forms of pedogenic iron. Changes with time in accumulated mass of amorphous forms of pedogenic aluminum, Al(o), are negligible within the first 29 ka, then reflect a rapid increase in rate of accumulation until at least 124 ka. Two pedons from the same terrace (inferred age 124 ka) contain strikingly different amounts of pedogenic Al(o), however, and suggest that Al(o) may be an unreliable indicator of the degree of soil development. In addition to mass values of different soil substances, maximum percent values were calculated. Soils developed on marine terraces older than 29 ka have at least 10% maximum clay, older than 100 ka at least 30% maximum clay, and older than 240 ka at least 40-50% maximum clay. Soils on terraces younger than 29 ka have less than 1% maximum Fe(d), and soils older than 240 ka at have at least 4% maximum Fe(d). These easily obtained values provide textural and chemical boundaries for separating marine terraces younger or older than about 29, 100, and 240 ka in this region, but are useful only as very general tools for correlation. Maximum percent clay is a more reliable indicator of soil age than maximum percent Fe(d), as the latter is greatly influenced by local groundwater flux, and percent values of Fe(d) have a high degree of scatter. C1 UNIV ARIZONA,DEPT SOILS & WATER SCI,TUCSON,AZ 85721. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP MERRITTS, DJ (reprint author), FRANKLIN & MARSHALL COLL,DEPT GEOL,LANCASTER,PA 17604, USA. NR 42 TC 65 Z9 67 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0016-7061 J9 GEODERMA JI Geoderma PD NOV PY 1991 VL 51 IS 1-4 BP 241 EP 275 DI 10.1016/0016-7061(91)90073-3 PG 35 WC Soil Science SC Agriculture GA GN999 UT WOS:A1991GN99900012 ER PT J AU PULKKINEN, TI BAKER, DN FAIRFIELD, DH PELLINEN, RJ MURPHREE, JS ELPHINSTONE, RD MCPHERRON, RL FENNELL, JF LOPEZ, RE NAGAI, T AF PULKKINEN, TI BAKER, DN FAIRFIELD, DH PELLINEN, RJ MURPHREE, JS ELPHINSTONE, RD MCPHERRON, RL FENNELL, JF LOPEZ, RE NAGAI, T TI MODELING THE GROWTH-PHASE OF A SUBSTORM USING THE TSYGANENKO MODEL AND MULTI-SPACECRAFT OBSERVATIONS - CDAW-9 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TAIL CURRENT SHEET; ONSET AB The CDAW-9 Event C focused upon the early part of 3 May 1986 when a large substorm onset occurred at 0111 UT. By modifying the Tsyganenko 1989 magnetic field model, we construct a model in which the near-Earth current systems are enhanced with time to describe the observed development of the tail magnetic field during the growth phase. The cross-tail current intensity and the thickness of the current sheet are determined by comparison with three space-craft in the near-Earth tail. The location of the auroral bulge as recorded by the Viking imager is mapped to the equatorial current sheet. The degree of chaotization of the thermal electrons is estimated, and the consequences to the tail stability towards ion tearing are discussed. We conclude that the mapping of the brightening region in the auroral oval corresponds to the regions in the tail where the current sheet may be unstable towards ion tearing. C1 UNIV CALGARY,CALGARY T2N 1N4,ALBERTA,CANADA. AEROSPACE CORP,SPACE SCI LAB,EL SEGUNDO,CA 90245. APPL RES CORP,LANDOVER,MD 20785. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 92024. JAPAN METEOROL AGCY,METEOROL RES INST,TOKYO,JAPAN. FINNISH METEOROL INST,HELSINKI,JAPAN. RP PULKKINEN, TI (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Pulkkinen, Tuija/D-8403-2012; OI Pulkkinen, Tuija/0000-0002-6317-381X; Lopez, Ramon/0000-0001-5881-1365 NR 10 TC 107 Z9 107 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 NOV PY 1991 VL 18 IS 11 BP 1963 EP 1966 DI 10.1029/91GL02002 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500009 ER PT J AU CHAO, BF DONG, DN LIU, HS HERRING, TA AF CHAO, BF DONG, DN LIU, HS HERRING, TA TI LIBRATION IN THE EARTHS ROTATION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB External luni-solar torque exerted on the difference (B-A) of the Earth's two equatorial principal moments of inertia gives rise to two types of librational motions in the Earth's rotation: the semidiurnal libration in spin and the prograde diurnal libration in polar motion. Formulas for the librations considering a realistic Earth model and their tidal decompositions are derived and evaluated. The spin libration has a maximum peak-to-peak amplitude of 0.09 milliarcseconds. Implications concerning their detectability and role in the tidal variation of Earth rotation are discussed. C1 MIT,DEPT EARTH ATMOSPHERE & PLANETARY SCI,CAMBRIDGE,MA 02139. RP CHAO, BF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. RI Chao, Benjamin Fong/N-6156-2013 NR 16 TC 28 Z9 29 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV PY 1991 VL 18 IS 11 BP 2007 EP 2010 DI 10.1029/91GL02491 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500020 ER PT J AU ARGUS, DF GORDON, RG AF ARGUS, DF GORDON, RG TI NO-NET-ROTATION MODEL OF CURRENT PLATE VELOCITIES INCORPORATING PLATE MOTION MODEL NUVEL-1 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HOTSPOTS AB We present NNR-NUVEL1, a model of plate velocities relative to the unique reference frame defined by requiring no-net-rotation of the lithosphere while constraining relative plate velocities to equal those in global plate motion model NUVEL-1 [DeMets et al., 1990]. Differences between NNR-NUVEL1 and no-net-rotation plate motion model AM0-2 [Minster and Jordan, 1978] are as large as 15 mm/yr. In NNR-NUVEL1, the Pacific plate rotates in a right-handed sense relative to the no-net-rotation reference frame at 0.67-degrees/m.y. about 63-degrees-S, 107-degrees-E. This rotation nearly parallels, but is 32% slower than, the Pacific-hotspot Euler vector of HS2-NUVEL1, which is a global model of plate-hotspot velocities constrained to consistency with NUVEL-1 [Gripp and Gordon, 1990]. At Hawaii the Pacific plate moves relative to the no-net-rotation reference frame at 70 mm/yr, which is 25 mm/yr slower than the Pacific plate moves relative to the hotspots. Differences between NNR-NUVEL1 and HS2-NUVEL1 are described completely by a right-handed rotation of 0.33-degrees/m.y. about 49-degrees-S, 65-degrees-E. The 99% confidence ellipsoids for plate-hotspot motion in model HS2-NUVEL1 exclude the corresponding Euler vectors from model NNR-NUVEL1. Thus the no-net-rotation reference frame differs significantly from the hotspot reference frame. If the difference between reference frames is caused by motion of the hotspots relative to a mean mantle reference frame, then hotspots beneath the Pacific plate move with coherent motion towards the east-southeast. Alternatively, the difference between reference frames may show that the uniform drag, no-net-torque reference frame, which is kinematically equivalent to the no-net-rotation reference frame, is based on a dynamically incorrect premise. Possible exceptions to the assumption of uniform drag include a net torque on the lithosphere due to attached subducting slabs and greater resistance to plate motion beneath continents than beneath oceans. C1 NORTHWESTERN UNIV,DEPT GEOL SCI,EVANSTON,IL 60208. RP ARGUS, DF (reprint author), CALTECH,JET PROP LAB,MAIL STOP 238 332,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Argus, Donald/F-7704-2011 NR 15 TC 241 Z9 271 U1 2 U2 18 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 NOV PY 1991 VL 18 IS 11 BP 2039 EP 2042 DI 10.1029/91GL01532 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500028 ER PT J AU GUINNESS, EA ARVIDSON, RE IRONS, JR HARDING, DJ AF GUINNESS, EA ARVIDSON, RE IRONS, JR HARDING, DJ TI SURFACE SCATTERING PROPERTIES ESTIMATED FROM MODELING ASAS MULTIPLE EMISSION ANGLE REFLECTANCE DATA OVER THE LUNAR CRATER VOLCANIC FIELD, NEVADA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SPECTROSCOPY; ROUGHNESS AB ASAS multispectral data were acquired over Lunar Lake playa at 12 different lighting and viewing geometries. Atmospheric models and field-based data demonstrate that atmospheric contributions to ASAS data were relatively small (< 15%) and were thus ignored in analyses of surface photometric properties. ASAS data of an artificially roughened playa and cobble-strewn surfaces exhibit trends of increasing reflectance as phase angle decreases. The reflectance of a natural playa surface exhibits Lambertian scattering properties that cannot be replicated with the Hapke [1986] photometric function. The Hapke model does fit the rough and cobble-strewn playa data with single scattering albedo, asymmetry factor, and roughness terms consistent with known properties of these surfaces. No published photometric model explains the reflectance variations of all three surfaces. C1 NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771. UNIV MARYLAND,DEPT GEOL,COLLEGE PK,MD 20742. RP GUINNESS, EA (reprint author), WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,DEPT EARTH & PLANETARY SCI,ST LOUIS,MO 63130, USA. RI Irons, James/D-8535-2012; Harding, David/F-5913-2012 NR 14 TC 2 Z9 2 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV PY 1991 VL 18 IS 11 BP 2051 EP 2054 DI 10.1029/91GL02664 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500031 ER PT J AU POTTER, AE MORGAN, TH AF POTTER, AE MORGAN, TH TI OBSERVATIONS OF THE LUNAR SODIUM EXOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; ATMOSPHERE; MERCURY; POTASSIUM; MOON AB Measurements of sodium resonance emission showed that the sodium exosphere of the Moon extends up to 1500 km. altitude above the equatorial limb. The line-of-sight sodium atom densities at various altitudes were derived from the measured sodium emission intensities, using a calibration based on brightness of the lunar limb. The data were fit to a simple two-parameter model of the exosphere. Above the equatorial limb, this yielded apparent temperatures of 950-1150-degrees-K., and surface densities of sodium atoms of 29 - 46 atoms/cm3. Above the north pole, adjacent to the polar terminator, the temperature was much less, 450-degrees-K., and the surface density rose to 65 atoms/cm3. Sodium emission could not be detected above the equatorial terminator, indicating a decrease to levels below about 200 Rayleighs, difficult to distinguish from the sodium nightglow. Solar wind impact on the surface does not seem to be an important factor, because the sodium density changed very little when the Moon was shielded from the direct solar wind by the Earth's magnetotail. This suggests that solar photon radiation plays a major role in maintenance of high kinetic temperatures in the sodium exosphere. C1 NASA,NATL RES COUNCIL,WASHINGTON,DC 20546. RP POTTER, AE (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN3,HOUSTON,TX 77058, USA. RI Morgan, Thomas/I-5943-2013 NR 17 TC 26 Z9 26 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 NOV PY 1991 VL 18 IS 11 BP 2089 EP 2092 DI 10.1029/91GL02621 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500041 ER PT J AU HUNTEN, DM KOZLOWSKI, RWH SPRAGUE, AL AF HUNTEN, DM KOZLOWSKI, RWH SPRAGUE, AL TI A POSSIBLE METEOR-SHOWER ON THE MOON SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TENUOUS LUNAR ATMOSPHERE; SODIUM; POTASSIUM AB Over the 3-day period from 12 to 14 October, 1990, the sodium abundance in the lunar atmosphere at 80-degrees South increased by 60%, while interspersed measurements at the equator showed no substantial change. The source is suggested to be an unknown meteor shower with a radiant near the south ecliptic pole. A low relative velocity of approximately 20 km/sec, combined with small particle masses, would keep the shower below the detectability threshold of radar. The stream could evolve from a reasonable asteroidal or cometary orbit with perihelion somewhat greater than 1 astronomical unit (AU) and a major axis of a few AU. The short residence time of lunar sodium makes it much more favorable than the terrestrial sodium layer for detection of such an event. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HUNTEN, DM (reprint author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA. NR 20 TC 35 Z9 35 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV PY 1991 VL 18 IS 11 BP 2101 EP 2104 DI 10.1029/91GL02543 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500044 ER PT J AU FREEMAN, JW HILLS, HK AF FREEMAN, JW HILLS, HK TI THE APOLLO LUNAR-SURFACE WATER-VAPOR EVENT REVISITED SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB On March 7, 1971, the first sunrise following the Apollo 14 mission, the Suprathermal Ion Detector Experiment (SIDE) deployed at the Apollo 14 site reported an intense flux of ions whose mass per charge was consistent with water vapor. We examine the amount of water and discuss the various acceleration processes responsible for accelerating ions into the SIDE. We conclude that during most of the event the observed water vapor ions were accelerated by the negative lunar surface electric potential and secondly that this event was probably the result of mission associated water vapor, either from the LM ascent and descent stage rockets or from residual water in the descent stage tanks. C1 NASA,GODDARD SPACE FLIGHT CTR,CTR NATL SPACE SCI DATA,GREENBELT,MD 20771. RP FREEMAN, JW (reprint author), RICE UNIV,DEPT SPACE PHYS & ASTRON,HOUSTON,TX 77251, USA. NR 16 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 NOV PY 1991 VL 18 IS 11 BP 2109 EP 2112 DI 10.1029/91GL02625 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500046 ER PT J AU ZOOK, HA MCCOY, JE AF ZOOK, HA MCCOY, JE TI LARGE-SCALE LUNAR HORIZON GLOW AND A HIGH-ALTITUDE LUNAR DUST EXOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERE; POTASSIUM; SODIUM; MOON AB All three Apollo 17 astronauts sketched a "lunar horizon glow," seen from orbit above the Moon. It is shown that the shape of the glow is compatible with scattering of sunlight off of gas or dust at high altitudes above the Moon. Our mathematical modeling best simulates the glow with submicron dust grains whose spatial density varies with altitude above the Moon as exp(-H/H(s)), where H(s) is in the range of 5 to 20 km. These dust grains are probably electrically charged and ejected above the lunar surface by local electric fields. RP ZOOK, HA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN3,HOUSTON,TX 77058, USA. NR 18 TC 91 Z9 92 U1 0 U2 6 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 NOV PY 1991 VL 18 IS 11 BP 2117 EP 2120 DI 10.1029/91GL02235 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500048 ER PT J AU FELDMAN, WC REEDY, RC MCKAY, DS AF FELDMAN, WC REEDY, RC MCKAY, DS TI LUNAR NEUTRON LEAKAGE FLUXES AS A FUNCTION OF COMPOSITION AND HYDROGEN CONTENT SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SPECTRA; ICE AB Areas of the Moon that might have enhanced concentrations of hydrogen are discussed. The fluxes of thermal, epithermal, and fast neutrons escaping from the lunar surface were calculated for eight different compositions and several hydrogen contents. These flux ratios depend on composition and are very sensitive to the hydrogen content. Their measurement using flight-proven techniques from lunar orbit should allow detection and identification of hydrogen residing in either permanently shaded cold traps near the lunar poles or mature regoliths. Knowledge of composition, especially of Fe and Ti, improves the thresholds for hydrogen detection and also could allow identification of Gd and Sm. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP FELDMAN, WC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS-D438,LOS ALAMOS,NM 87545, USA. OI Reedy, Robert/0000-0002-2189-1303 NR 21 TC 29 Z9 29 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV PY 1991 VL 18 IS 11 BP 2157 EP 2160 DI 10.1029/91GL02618 PG 4 WC Geosciences, Multidisciplinary SC Geology GA GP755 UT WOS:A1991GP75500058 ER PT J AU LAUNIUS, RD AF LAUNIUS, RD TI MILITARY PERIODICALS - UNITED-STATES AND SELECTED INTERNATIONAL JOURNALS AND NEWSPAPERS - UNSWORTH,ME SO GOVERNMENT PUBLICATIONS REVIEW 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 PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0277-9390 J9 GOV PUBL REV PD NOV-DEC PY 1991 VL 18 IS 6 BP 733 EP 734 DI 10.1016/0277-9390(91)90184-Y PG 2 WC Information Science & Library Science SC Information Science & Library Science GA GW381 UT WOS:A1991GW38100019 ER PT J AU GOLDSTEIN, JJ MUMMA, MJ KOSTIUK, T DEMING, D ESPENAK, F ZIPOY, D AF GOLDSTEIN, JJ MUMMA, MJ KOSTIUK, T DEMING, D ESPENAK, F ZIPOY, D TI ABSOLUTE WIND VELOCITIES IN THE LOWER THERMOSPHERE OF VENUS USING INFRARED HETERODYNE SPECTROSCOPY SO ICARUS LA English DT Article ID NATURAL LASER-EMISSION; GENERAL-CIRCULATION; NIGHT AIRGLOW; ZONAL WINDS; TEMPERATURE; ATMOSPHERE; MESOSPHERE; MODEL; TRANSITIONS; DYNAMICS C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,PLANETARY SYST BRANCH,GREENBELT,MD 20771. UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742. RP GOLDSTEIN, JJ (reprint author), SMITHSONIAN INST,NATL AIR & SPACE MUSEUM,ASTROPHYS LAB,WASHINGTON,DC 20560, USA. RI mumma, michael/I-2764-2013; Kostiuk, Theodor/A-3077-2014 NR 44 TC 49 Z9 49 U1 3 U2 3 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 NOV PY 1991 VL 94 IS 1 BP 45 EP 63 DI 10.1016/0019-1035(91)90140-O PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR704 UT WOS:A1991GR70400004 ER PT J AU HINSON, DP MAGALHAES, JA AF HINSON, DP MAGALHAES, JA TI EQUATORIAL WAVES IN THE STRATOSPHERE OF URANUS SO ICARUS LA English DT Article ID TURBULENT PLANETARY ATMOSPHERES; RADIO OCCULTATION MEASUREMENTS; STELLAR OCCULTATIONS; THERMAL STRUCTURE; VOYAGER; SHEAR; OSCILLATION; SATELLITES; ENERGY; PHASE C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HINSON, DP (reprint author), STANFORD UNIV,CTR RADAR ASTRON,STANFORD,CA 94305, USA. NR 49 TC 24 Z9 24 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 1991 VL 94 IS 1 BP 64 EP 91 DI 10.1016/0019-1035(91)90141-F PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR704 UT WOS:A1991GR70400005 ER PT J AU WARD, WR RUDY, DJ AF WARD, WR RUDY, DJ TI RESONANT OBLIQUITY OF MARS SO ICARUS LA English DT Article ID SOLAR-SYSTEM; ASTRONOMICAL THEORY; MARTIAN VALLEYS; OSCILLATIONS C1 SAN JUAN CAPISTRANO RES INST,SAN JUAN CAPISTRANO,CA. RP WARD, WR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 23 TC 32 Z9 31 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 0019-1035 J9 ICARUS JI Icarus PD NOV PY 1991 VL 94 IS 1 BP 160 EP 164 DI 10.1016/0019-1035(91)90146-K PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR704 UT WOS:A1991GR70400010 ER PT J AU ROUSH, T POLLACK, J ORENBERG, J AF ROUSH, T POLLACK, J ORENBERG, J TI DERIVATION OF MIDINFRARED (5-25 MU-M) OPTICAL-CONSTANTS OF SOME SILICATES AND PALAGONITE SO ICARUS LA English DT Article ID INFRARED-SPECTROSCOPY; MARTIAN DUST; ROCKS; REFLECTANCE; MICROWAVE; MINERALS; REGION; ICE C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SAN FRANCISCO STATE UNIV,DEPT CHEM,SAN FRANCISCO,CA 94132. RP ROUSH, T (reprint author), SAN FRANCISCO STATE UNIV,DEPT GEOSCI,1600 HOLLOWAY AVE,SAN FRANCISCO,CA 94132, USA. NR 39 TC 88 Z9 88 U1 0 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 NOV PY 1991 VL 94 IS 1 BP 191 EP 208 DI 10.1016/0019-1035(91)90150-R PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR704 UT WOS:A1991GR70400014 PM 11538089 ER PT J AU REID, MB PIESTRUP, MA AF REID, MB PIESTRUP, MA TI RESONANCE TRANSITION RADIATION X-RAY LASER SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID FREE-ELECTRON-LASER; GAIN AB A free electron laser is proposed using a periodic dielectric and helical magnetic field. Periodic synchronism between the electrons and the optical wave is obtained at the period of the dielectric and not at the period of the helical magnetic field as in the case of other types of free electron lasers. The synchronism condition and the gain of the new device are derived. The effects on the gain from dephasing and beam expansion due to elastic scattering of the electrons in the periodic medium are included in the gain calculation. Examples of the resonance transition radiation laser and klystron are given. Operation at photon energies between 2.5 and 3.5 KeV with net gain up to 12% is feasible using high electron-beam energies of 3 and 5 GeV. Moderate (300 MeV) beam energy allows operation between 80 to 110 eV with up to 57% net gain using a klystron design. In both cases, rapid foil heating may limit operation to a single electron-beam pulse. C1 ADELPHI TECHNOL INC,PALO ALTO,CA 94301. RP REID, MB (reprint author), NASA,AMES RES CTR,INTELLIGENT SYST TECHNOL BRANCH,MOFFETT FIELD,CA 94035, USA. NR 27 TC 9 Z9 10 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 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD NOV PY 1991 VL 27 IS 11 BP 2440 EP 2455 DI 10.1109/3.100883 PG 16 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA GN879 UT WOS:A1991GN87900010 ER PT J AU ELEFTHERIADES, GV ALIAHMAD, WY KATEHI, LPB REBEIZ, GM AF ELEFTHERIADES, GV ALIAHMAD, WY KATEHI, LPB REBEIZ, GM TI MILLIMETER-WAVE INTEGRATED-HORN ANTENNAS .1. THEORY SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID MICROSTRIP DISCONTINUITIES; GUIDE AB Dipole excited integrated horn antennas etched in Si/GaAs are a very promising class of antennas for millimeter and submillimeter applications. Areas of application include imaging and tracking through rain and fog, remote sensing, radio astronomy, and plasma diagnostics. In this paper (Part I), the far-field pattern and input impedance of a dipole-fed horn antenna in a ground plane are calculated using full-wave analysis. The solution is based on the numerical evaluation of the pertinent Green's function for the horn structure and the application of the method of moments. The convergence characteristics of the full-wave analysis method are investigated, along with the resonant properties of the strip-dipole and the corresponding behavior of the far-field patterns. The theoretical results are compared in Part II with microwave and millimeter-wave measurements. C1 UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109. RP ELEFTHERIADES, GV (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109, USA. NR 15 TC 28 Z9 28 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 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD NOV PY 1991 VL 39 IS 11 BP 1575 EP 1581 DI 10.1109/8.102771 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA GP926 UT WOS:A1991GP92600005 ER PT J AU ALIAHMAD, WY ELEFTHERIADES, GV KATEHI, LPB REBEIZ, GM AF ALIAHMAD, WY ELEFTHERIADES, GV KATEHI, LPB REBEIZ, GM TI MILLIMETER-WAVE INTEGRATED-HORN ANTENNAS .2. EXPERIMENT SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article AB The impedance and radiation patterns of a dipole-fed integrated horn antenna in a ground plane are experimentally investigated at microwave and millimeter-wave frequencies. The agreement with the full-wave analysis technique presented in Part I is good. The results indicate that for a 70-degrees flare-angle horn, horn apertures from 1.0-lambda-square to 1.5-lambda-square with dipole positions between 0.36 and 0.55-lambda yield good radiation patterns with a gain between 10-13 dB, a cross-polarization level lower than -20 dB, and resonant dipole impedances between 40-OMEGA and 120-OMEGA. It is also found that the impedance measurements can be safely used for two-dimensional horn arrays, but the radiation patterns differ because of the Floquet modes associated with the array environment. The integrated horn antenna is a high-efficiency antenna suitable for applications in millimeter-wave imaging systems, remote-sensing, and radio astronomy. C1 UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109. RP ALIAHMAD, WY (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109, USA. NR 6 TC 10 Z9 10 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 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD NOV PY 1991 VL 39 IS 11 BP 1582 EP 1586 DI 10.1109/8.102772 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA GP926 UT WOS:A1991GP92600006 ER PT J AU NGUYEN, TM AF NGUYEN, TM TI THE IMPACT OF NRZ DATA ASYMMETRY ON THE PERFORMANCE OF A SPACE TELEMETRY SYSTEM SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article AB The telemetry data asymmetry due to rising and falling voltage transitions can cause undesired spectral components at the output of the spacecraft's transmitter. Performance of a space telemetry system can potentially degrade due to these undesired components. This paper derives an expression for the power spectral density of an asymmetric NRZ data stream. This formula is then used to investigate how the data bandwidth varies with data asymmetry. The threshold levels of undesired spectral components that fall into the carrier tracking loop bandwidth are determined by examining the derived spectral density. Further, based on this formula, a simple technique is developed for the computation of bit signal-to-noise ratio (SNR) degradation due to data asymmetry. The telemetry bit SNR degradations derived using this technique are compared to the results obtained previously [2], and with measurements by the Electronic Systems Test Laboratory (ESTL) at the Lyndon B. Johnson Space Center. RP NGUYEN, TM (reprint author), CALTECH,JET PROP LAB,MS 238343,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD NOV PY 1991 VL 33 IS 4 BP 343 EP 350 DI 10.1109/15.99116 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA GK638 UT WOS:A1991GK63800009 ER PT J AU BISHOP, DF AF BISHOP, DF TI THE EFFECT OF IONOSPHERIC REFLECTED NOISE ON THE PERFORMANCE OF AN ORBITAL-DEBRIS RADAR SYSTEM SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Note AB An orbital-debris radar system is designed to detect the presence of small objects in low Earth orbit by reflecting radio waves off the objects. Free electrons and ions contained in the ionosphere cause incoherent scatter of the radar signal. This ionospheric reflection tends to increase the noise at the terrestrial radar receiver. A parameter called the ionospheric scattering cross section per unit volume, which is a function of altitude, is useful for computing the power of the ionospheric reflected signal. The doppler frequency spread of the ionospheric reflected signal is a function of altitude, also. The ionospheric noise of a 9-GHz orbital-debris radar receiver is computed using these concepts. Annual and diurnal variations of the noise are included. RP BISHOP, DF (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD NOV PY 1991 VL 33 IS 4 BP 362 EP 366 DI 10.1109/15.99119 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA GK638 UT WOS:A1991GK63800012 ER PT J AU WAY, JB PARIS, J DOBSON, MC MCDONALD, K ULABY, FT WEBER, JA USTIN, S VANDERBILT, VC KASISCHKE, ES AF WAY, JB PARIS, J DOBSON, MC MCDONALD, K ULABY, FT WEBER, JA USTIN, S VANDERBILT, VC KASISCHKE, ES TI DIURNAL CHANGE IN TREES AS OBSERVED BY OPTICAL AND MICROWAVE SENSORS - THE EOS SYNERGISM STUDY SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB The EOS Synergism Study examined the temporal variability of the optical reflectance and microwave backscatter due to diurnal change in canopy properties of interest to ecosystem modelers. The experiment was designed specifically to address diurnal changes in canopy water status (including water potential and content) that relate to transpiration. Multispectral optical and multifrequency, multipolarization microwave measurements were acquired using boom-truck-based systems over a 2-week period in August 1987. Sensor and canopy properties were collected around the clock. The canopy under study was a walnut orchard in the San Joaquin Valley of California. The results demonstrate large diurnal variations in the dielectric properties of the tree (the stem, or bole, specifically) that in turn produce significant diurnal changes in the microwave backscatter. The change in dielectric constant is related to the diurnal change in water potential, although the specific physical or physiological relationship has not yet been established. A diurnal change in optical reflectance could be attributed primarily to sun angle-view angle change. Although some changes in canopy spectral properties were also observed, these could not be distinguished from edge effects of the canopy. The results suggest that permanently orbiting spaceborne sensors such as those on EOS should be placed in orbits that are optimized for the individual sensor and need not be tied together by a tight simultaneity requirement on the order of minutes to hours for the purpose of monitoring ecosystem properties. Microwave sensors, although able to image day or night, are sensitive to the diurnal pattern of change in vegetation canopies and, therefore, should be in sun synchronous orbits with a node crossing time selected to optimize sensitivity to the diurnal patterns (4-6 p.m. for this canopy and season). Furthermore, comparison of the long-term spaceborne synthetic aperture radar (SAR) data sets collected with SAR in different equator crossing time orbits must consider potential diurnal variation in the surface properties and the effects on the backscatter. Optical reflectance is affected more by sun-angle/view angle variations than a diurnal change in canopy water properties. Therefore, based on the results of this study, optical sensors should be placed in orbits which minimize the influence of clouds on terrestrial data acquisition. C1 ENVIRONM INST MICHIGAN,ANN ARBOR,MI. CALIF STATE UNIV FRESNO,SCH NAT SCI,DEPT BIOL,FRESNO,CA 93740. UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,RADIAT LAB,ANN ARBOR,MI 48109. UNIV CALIF DAVIS,DEPT MED,DAVIS,CA 95616. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. US EPA,CORVALLIS ENVIRONM RES LAB,CORVALLIS,OR 97330. RP WAY, JB (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 19 TC 24 Z9 24 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 NOV PY 1991 VL 29 IS 6 BP 807 EP 821 DI 10.1109/TGRS.1991.1019466 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA GN485 UT WOS:A1991GN48500001 ER PT J AU CASEY, D WAY, JB AF CASEY, D WAY, JB TI ORBIT SELECTION FOR THE EOS MISSION AND ITS SYNERGISM IMPLICATIONS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB The fundamentals of orbital mechanics are presented and applied to show how the baseline Earth Observing System orbits were selected. Scientific goals, spacecraft limitations, and instrument requirements are examined. Instrument synergism issues related to satellite orbits are discussed. RP CASEY, D (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 17 TC 5 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 1991 VL 29 IS 6 BP 822 EP 835 DI 10.1109/36.101361 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA GN485 UT WOS:A1991GN48500002 ER PT J AU USTIN, SL MARTENS, SN VANDERBILT, VC AF USTIN, SL MARTENS, SN VANDERBILT, VC TI CANOPY ARCHITECTURE OF A WALNUT ORCHARD SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID BETULA-PENDULA; NEIGHBORS; SCATTERING; GROWTH; TREES; BUDS AB A detailed dataset describing the canopy geometry of a walnut orchard was acquired to provide supporting information to test and compare the predictions of canopy microwave and optical inversion models. Measured canopy properties included the quantity, size, and orientation of stems, leaves, and fruit. Eight trees receiving 100% of estimated potential evapotranspiration water use and eight trees receiving 33% of potential water use were measured for these properties. The vertical distributions of stem, leaf, and fruit properties are presented with respect to irrigation treatment. Zenith and probability distributions for stems and leaf normals are also presented. These data show that after two years of reduced irrigation, the trees receiving only 33% of their potential water requirement had reduced fruit yields, lower leaf area index, and altered allocation of biomass within the canopy. Such architectural differences provide an opportunity to examine the resolution of optical and microwave sensors and model predictions associated with detecting small changes in canopy structure associated with modest levels of water stress. C1 UNIV CALIF DAVIS,DEPT BOT,DAVIS,CA 95616. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP USTIN, SL (reprint author), UNIV CALIF DAVIS,DEPT LAND AIR & WATER RESOURCES,DAVIS,CA 95616, USA. NR 22 TC 12 Z9 12 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 1991 VL 29 IS 6 BP 843 EP 851 DI 10.1109/TGRS.1991.1019468 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 GN485 UT WOS:A1991GN48500004 ER PT J AU VANDERBILT, VC USTIN, SL BERGER, KM CALDWELL, WF CLARK, JA GANAPOL, BD KASISCHKE, ES MARTENS, SN PETTIGREW, RE ROUSSEAU, RA AF VANDERBILT, VC USTIN, SL BERGER, KM CALDWELL, WF CLARK, JA GANAPOL, BD KASISCHKE, ES MARTENS, SN PETTIGREW, RE ROUSSEAU, RA TI BIOPHYSICAL INFORMATION IN ASYMMETRIC AND SYMMETRICAL DIURNAL BIDIRECTIONAL CANOPY REFLECTANCE SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SPECTRAL RESPONSE; VIEW ANGLE; SURFACES; HARDWOOD; MODEL AB In this paper we present a new theory for partitioning the information content in diurnal bidirectional reflectance measurements in order to detect differences potentially related to biophysical variables. We collected optic al data diurnally on two orchard canopies at as many as nine view nadir angles in the principal plane. Even though one of the canopies was permanently water stressed and the other was stressed each day, the results of a search for a water stress 'signature' in the reflectance data proved inconclusive. C1 FUJITSU MICROELECTR INC,SAN JOSE,CA 94134. UNIV CALIF DAVIS,DEPT LAND AIR & WATER RESOURCES,DAVIS,CA 95616. UNIV ARIZONA,DEPT NUCL & ENERGY ENGN,TUCSON,AZ 85721. ENVIRONM RES INST MICHIGAN,CTR EARTH SCI,ANN ARBOR,MI 48107. RP VANDERBILT, VC (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 21 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 1991 VL 29 IS 6 BP 875 EP 889 DI 10.1109/TGRS.1991.1019471 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA GN485 UT WOS:A1991GN48500007 ER PT J AU ZEBKER, HA VANZYL, JJ DURDEN, SL NORIKANE, L AF ZEBKER, HA VANZYL, JJ DURDEN, SL NORIKANE, L TI CALIBRATED IMAGING RADAR POLARIMETRY - TECHNIQUE, EXAMPLES, AND APPLICATIONS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SCATTERING AB We have developed a calibration procedure for imaging radar polarimeters and applied it to a set of images acquired by the NASA DC-8 multifrequency radar system. Our technique requires the use of ground reflectors of known cross-section for absolute calibration, that is solution for sigma-0; however, the image data themselves can usually provide all information necessary for phase calibration and for antenna cross-talk correction. The accuracy of our approach, as measured by calculating the cross-section residuals of known targets in each calibrated scene, is on the order of +/- 1-2 dB at P- and C-band, but improves to +/- 0.5 dB at L-band. We present here the results of applying our technique to radar scenes of lava flows of varying roughness, temperate and tropical rain forests, and ocean water surfaces. We also present several example applications which are feasible assuming the calibration of the data but which would be difficult to implement with uncalibrated data. C1 CALTECH,JET PROP LAB,RADAR SYST SCI & ENGN GRP,TECH STAFF,PASADENA,CA 91109. NR 23 TC 31 Z9 31 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 1991 VL 29 IS 6 BP 942 EP 961 DI 10.1109/36.101373 PG 20 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA GN485 UT WOS:A1991GN48500014 ER PT J AU WAY, JB SMITH, EA AF WAY, JB SMITH, EA TI THE EVOLUTION OF SYNTHETIC APERTURE RADAR SYSTEMS AND THEIR PROGRESSION TO THE EOS SAR SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SHUTTLE IMAGING RADAR; EASTERN SAHARA; ICE-MOTION; SIR-B; TITAN; SEASAT; OCEAN; ATMOSPHERE; IMAGERY AB The spaceborne imaging radar program of the National Aeronautics and Space Administration (NASA) has evolved primarily through Seasat and the Shuttle Imaging Radar (SIR) to a multifrequency, multipolarization system capable of monitoring the Earth with a variety of imaging geometries, resolutions, and swaths. In particular, the ability to digitally process and calibrate the data has been a key factor in developing the algorithms which will operationally provide geophysical and biophysical information about the surface of the Earth using synthetic aperture radar (SAR). This paper describes the evolution of the spaceborne imaging radar starting with the Seasat SAR, through the SIR-A, SIR-B, and SIR-C/X-SAR missions, to the EOS SAR which is scheduled for launch as part of the Earth Observing System (EOS) at the end of the 1990s. A summary of the planned international missions, which may produce a permanent active microwave capability in space starting as early as 1991, is also presented, along with a description of the airborne systems which will be essential to the algorithm development and long-term calibration of the space-borne data. Finally, a brief summary of the planetary missions utilizing SAR and a comparison of their imaging capabilities with those available on Earth is presented. RP WAY, JB (reprint author), CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. NR 78 TC 27 Z9 28 U1 2 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 NOV PY 1991 VL 29 IS 6 BP 962 EP 985 DI 10.1109/36.101374 PG 24 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA GN485 UT WOS:A1991GN48500015 ER PT J AU MCCONNELL, R KWOK, R CURLANDER, JC KOBER, W PANG, SS AF MCCONNELL, R KWOK, R CURLANDER, JC KOBER, W PANG, SS TI PSI-S CORRELATION AND DYNAMIC TIME WARPING - 2 METHODS FOR TRACKING ICE FLOES IN SAR IMAGES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB In recent years, there has been an interest in automating the process of producing maps of the motion of ice floes from SAR images acquired a few days apart. A common approach is to correlate raw pixel values in order to find corresponding features in two images. The problem with this approach is that the search space is often prohibitive when ice floes rotate, as they frequently do. We present two algorithms for performing shape matching on ice floe boundaries in SAR images. These algorithms quickly produce a set of ice motion and rotation vectors that can be used to guide a pixel value correlator. The algorithms match a shape descriptor known as the psi-s curve. The first algorithm uses normalized correlation to match the psi-s curves, while the second uses dynamic programming to compute an elastic match that better accommodates ice floe deformation. C1 CALTECH, JET PROP LAB, DIV RADAR SCI & ENGN, PASADENA, CA 91109 USA. CALTECH, JET PROP LAB, RADAR SCI & ENGN SECT, PASADENA, CA 91109 USA. RP VEXEL CORP, BOULDER, CO 80301 USA. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 12 TC 31 Z9 31 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 1991 VL 29 IS 6 BP 1004 EP 1012 DI 10.1109/36.101377 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 GN485 UT WOS:A1991GN48500018 ER PT J AU VRANISH, JM NAIK, DP RESTORFF, JB TETER, JP AF VRANISH, JM NAIK, DP RESTORFF, JB TETER, JP TI MAGNETOSTRICTIVE DIRECT DRIVE ROTARY MOTOR DEVELOPMENT SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 5TH JOINT MMM-INTERMAG CONF CY JUN 18-21, 1991 CL PITTSBURGH, PA SP AKASHIC MEMORIES, ALLEGHENY LUDLUM, ALLIED SIGNAL, APPL MAGNET, ARMCO, ANORD ENGN, BASF AG, CERAM MAGNET, CRUCIBLE MAT, DASTEK AB Highly magnetostrictive materials such as Tb.3Dy.7Fe2, commercially known as TERFENOL-D, have been used to date in a variety of devices such as high power actuators and linear motors. The larger magnetostriction available in twinned single crystal TERFENOL-D, approximately 2000 ppm at moderate magnetic field strengths, makes possible a new generation of magneto-mechanical devices. The authors are investigating the potential of this material as the basis of a direct micro-stepping rotary motor. Such a motor would be a high torque micro-radian stepper, capable of precision movements and self-braking in the power off state. The thrust of this paper is to present one motor prototype being developed based on the proven "Inch Worm" technique. Results of mathematical modelling techniques will be presented, to include magnetic, structural and both linear and non-linear dynamic calculations. In addition, test results on prototype hardware will be presented. C1 USN,CTR SURFACE WARFARE R43,SILVER SPRING,MD 20903. RP VRANISH, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 6 TC 23 Z9 33 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD NOV PY 1991 VL 27 IS 6 BP 5355 EP 5357 DI 10.1109/20.278837 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA HB661 UT WOS:A1991HB66100233 ER PT J AU JEDREY, TC DESSOUKY, KI LAY, NE AF JEDREY, TC DESSOUKY, KI LAY, NE TI AN AERONAUTICAL-MOBILE SATELLITE EXPERIMENT SO IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY LA English DT Article AB This paper describes the results of a joint NASA/FAA/INMARSAT satellite experiment employing the JPL developed land-mobile satellite communication terminal. This was the first satellite demonstration of the technologies developed under NASA's Mobile Satellite Experiment Task (MSAT-X). The technologies are both power and bandwidth efficient as required in the mobile satellite application. The experiment was performed in two parts during the first several months of 1989. The first segment of the experiment consisted of establishing a full duplex 4800 b/s digital data and voice communication link through the INMARSAT Marecs B2 satellite between Atlantic City, NJ, and Southbury, CT. The second segment consisted of establishing the same communication link between Southbury and a Boeing 727 B100 aircraft flying along the East Coast of the United States. During both segments, a series of tests was performed to characterize the terminal performance over the links. The experimental setup and the results of the speech and data experiments are presented in this paper. Any differences in performance between theory/simulation, laboratory, and field operation are emphasized and analyzed. RP JEDREY, TC (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 11 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 0018-9545 J9 IEEE T VEH TECHNOL JI IEEE Trans. Veh. Technol. PD NOV PY 1991 VL 40 IS 4 BP 741 EP 749 DI 10.1109/25.108385 PG 9 WC Engineering, Electrical & Electronic; Telecommunications; Transportation Science & Technology SC Engineering; Telecommunications; Transportation GA GU782 UT WOS:A1991GU78200010 ER PT J AU WILLNER, Y HEYMANN, M AF WILLNER, Y HEYMANN, M TI SUPERVISORY CONTROL OF CONCURRENT DISCRETE-EVENT SYSTEMS SO INTERNATIONAL JOURNAL OF CONTROL LA English DT Article AB When a discrete-event system P consists of several subsystems P1, ..., P(n) which operate concurrently, a natural approach to the supervisory control problem is to synthesize a 'local' controller S(i) for each subsystem P(i) and operate the individually controlled subsystems S(i)/P(i) concurrently. Such an approach is called concurrent supervisory control and is closely related to decentralized supervisory control as studied by Cieslak et al. (1988) and Lin and Wonham (1988). In the present paper simple and easily computable conditions are developed which guarantee that concurrent supervisory control can achieve the optimal behaviour achievable by a global supervisor. To achieve this, two specific concurrent control strategies are introduced. C1 TECHNION ISRAEL INST TECHNOL,DEPT COMP SCI,IL-32000 HAIFA,ISRAEL. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WILLNER, Y (reprint author), TECHNION ISRAEL INST TECHNOL,DEPT ELECT ENGN,IL-32000 HAIFA,ISRAEL. NR 13 TC 90 Z9 91 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0020-7179 J9 INT J CONTROL JI Int. J. Control PD NOV PY 1991 VL 54 IS 5 BP 1143 EP 1169 DI 10.1080/00207179108934202 PG 27 WC Automation & Control Systems SC Automation & Control Systems GA GK627 UT WOS:A1991GK62700005 ER PT J AU BAUSCHLICHER, CW BOUCHARD, F HEPBURN, JW MCMAHON, TB SURJASASMITA, I ROTH, LM GORD, JR FREISER, BS AF BAUSCHLICHER, CW BOUCHARD, F HEPBURN, JW MCMAHON, TB SURJASASMITA, I ROTH, LM GORD, JR FREISER, BS TI ON THE STRUCTURE OF AL(ACETONE)2+ SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article ID RESONANCE MASS-SPECTROMETRY; GAUSSIAN BASIS FUNCTIONS; TRANSITION-METAL IONS; ATOMIC BASIS SETS; FIRST-ROW ATOMS; GAS-PHASE; MOLECULAR CALCULATIONS; BINDING-ENERGIES; THERMOCHEMICAL PROPERTIES; WATER-MOLECULES AB Initial results from direct clustering measurements of enthalpies and entropies of binding of acetone to Al+ using a high pressure mass spectrometer led to the hypothesis that ligand-ligand bonding was involved in Al(acetone)2+. In this study, however, collision-induced dissociation, ligand-displacement reactions, and infrared multiphoton photodissociation of the mixed species Al(acetone)(acetone-d6)+ in a Fourier transform mass spectrometer show that the two acetone ligands in Al(acetone)2+ must be equivalent. Ab initio calculations support the conclusion that there are no ligand-ligand bonds, but that polarisation of the Al+ leads to both acetones binding on the same side. The resulting ligand-ligand interaction explains the difference in the observed entropy for the Al(acetone)+ system and those of other simple association reactions. Finally, direct clustering results from a newly constructed pulsed laser ionisation high pressure mass spectrometer are in excellent agreement with the Fourier transform mass spectrometry and ab initio findings. C1 UNIV WATERLOO,DEPT CHEM,WATERLOO N2L 3G1,ONTARIO,CANADA. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Forgrave, Sarah/I-3165-2012; McMahon, Terry/F-9904-2010 OI McMahon, Terry/0000-0002-0911-2733 NR 33 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD NOV 1 PY 1991 VL 109 BP 15 EP 30 DI 10.1016/0168-1176(91)85094-3 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA GN866 UT WOS:A1991GN86600003 ER PT J AU CHANG, ATC FOSTER, JL RANGO, A AF CHANG, ATC FOSTER, JL RANGO, A TI UTILIZATION OF SURFACE COVER COMPOSITION TO IMPROVE THE MICROWAVE DETERMINATION OF SNOW WATER EQUIVALENT IN A MOUNTAIN BASIN SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID RADIOMETERS; VEGETATION AB Satellite microwave data have been used to derive areal snow water equivalent in flat homogeneous areas with some success. Over heterogeneous mountainous areas different algorithms are needed to retrieve the water equivalent of the snow cover. A mixed pixel model based on the percentage of vegetation cover within a pixel has been developed to simulate the microwave brightness temperatures for the Rio Grande basin (3419 km2) in south-western Colorado. A relationship between the difference in microwave brightness temperature at two different frequencies (37 and 18 GHz horizontal polarization), and the basin-wide average snow water equivalent was obtained. The areal snow water equivalent values derived from the model were consistent with values generated by a reliable snowmelt run-off model using snow cover extent data. C1 USDA ARS,BELTSVILLE AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705. RP CHANG, ATC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 12 TC 34 Z9 38 U1 0 U2 4 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 NOV PY 1991 VL 12 IS 11 BP 2311 EP 2319 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA GM647 UT WOS:A1991GM64700010 ER PT J AU SCHAIRER, ET LEE, G MCDEVITT, TK AF SCHAIRER, ET LEE, G MCDEVITT, TK TI 2-DIMENSIONAL ADAPTIVE-WALL TESTS IN THE NASA AMES 2-FOOT BY 2-FOOT TRANSONIC WIND-TUNNEL SO JOURNAL OF AIRCRAFT LA English DT Article AB This paper describes the first tests conducted in the adaptive-wall test section of the 2- x 2-ft transonic wind tunnel at NASA Ames Research Center. The purpose of the tests was to demonstrate an automatic procedure for minimizing two-dimensional wall interference by actively controlling flow through the slotted upper and lower walls of the test section. Flow through the walls was by adjusting pressures in compartments of a segmented plenum. The procedure for determining the necessary pressure adjustments consisted of the following steps: 1) using a fast-scanning, two-component laser velocimeter to measure flow velocities along axial lines above and below the model; 2) testing the flow measurements for compatibility with free-air, far-field boundary conditions; and 3) using empirical influence coefficients to relate changes in flow velocity to changes in plenum pressures. A NACA 0012 airfoil was tested at Mach numbers between 0.70 and 0.85 and at angles of attack of 0 and 2 deg. In all cases, the procedure substantially reduced wall interference; however, measurable and significant interference persisted after the final plenum-pressure adjustments. The principal reason that interference could not be completely eliminated was that the effects of the plenum-pressure adjustments on the velocity measurements could not be predicted accurately. RP SCHAIRER, ET (reprint author), NASA,AMES RES CTR,FLUID DYNAM RES BRANCH,MOFFETT FIELD,CA 94035, 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 NOV PY 1991 VL 28 IS 11 BP 673 EP 682 DI 10.2514/3.46082 PG 10 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500001 ER PT J AU SCHIFF, LB DEGANI, D CUMMINGS, RM AF SCHIFF, LB DEGANI, D CUMMINGS, RM TI COMPUTATION OF 3-DIMENSIONAL TURBULENT VORTICAL FLOWS ON BODIES AT HIGH-INCIDENCE SO JOURNAL OF AIRCRAFT LA English DT Article AB As Navier-Stokes computations are carried out for high-angle-of-attack flows, the various numerical and physical factors affecting the accuracy of the flow predictions must be determined. In an effort to further this understanding, numerical predictions of the complex three-dimensional separated flow about bodies of revolution in supersonic and subsonic flows have been performed. Predictions have been made for the supersonic flow over a secant ogive cylinder at relatively low angles of attack using a thin-layer Navier-Stokes code, showing good agreement with experimental pressure measurements as well as boundary-layer velocity profiles. The predictions are also compared with parabolized Navier-Stokes computations from a previous work. Subsonic predictions at high angles of attack were made for a tangent ogive cylinder and were found to be in good agreement with available experimental data. The accuracy of the predictions are shown to depend on using grids that are sufficiently fine to resolve the details of both the viscous boundary layer and the off-surface separated flow structures and, for turbulent flow cases, the use of a turbulence model that accounts for the leeward vortical flow structures. An example of high-incidence flow computed about a more complex geometry, the F-18 fighter fuselage forebody and leading-edge extension, is also presented. RP SCHIFF, LB (reprint author), NASA,AMES RES CTR,DIV FLUID DYNAM,MOFFETT FIELD,CA 94035, USA. NR 0 TC 9 Z9 9 U1 1 U2 4 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 NOV PY 1991 VL 28 IS 11 BP 689 EP 699 DI 10.2514/3.46084 PG 11 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500003 ER PT J AU KORTE, JJ AF KORTE, JJ TI NUMERICAL-SIMULATION OF THE ACTUATION SYSTEM FOR THE ALDFS PROPULSION CONTROL VALVE SO JOURNAL OF AIRCRAFT LA English DT Article AB A numerical simulation of the actuation system for the propulsion control valve (PCV) of NASA Langley Aircraft Landing Dynamics Facility (ALDF) was developed during the preliminary design of the PCV and was used throughout the entire project. The numerical simulation is based on a predictive model of the PCV that was used to evaluate and design the unique actuation system. The PCV is a one-of-a-kind valve that controls a 1.7-million-lb thrust water jet used in propelling a 108,000-lb test carriage. The PCV can open and close in 0.300 s and deliver over 9000 gal of water per second at pressures up to 3150 psi. The actuation system of the PCV is a complicated mechanical-fluid power system designed for moving large masses at a high rate of acceleration. The design concept for the PCV was unique and it was built without the benefit of prototypes to verify the engineering design. The results of the numerical simulation of the PCV were used to predict transient performance and valve opening characteristics, specify the hydraulic control system, define transient loadings on components, and evaluate failure modes. The unique actuation system operated as the design intended and met the required performance without modification, largely because the results of the numerical simulation determined the required engineering parameters used to design the PCV. The mathematical model used for numerically simulating the mechanical fluid power system is described. Numerical results are demonstrated for a typical opening and closing cycle of the PCV. The computed results are shown to agree well with operational measurements. Finally, a summary is given on how the model was used in the design process. This paper demonstrates the advantages of having a predictive model for designing a complicated mechanical-fluid power system. RP KORTE, JJ (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,THEORET FLOW PHYS BRANCH,MAIL STOP 156,HAMPTON,VA 23665, USA. NR 0 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD NOV PY 1991 VL 28 IS 11 BP 700 EP 705 DI 10.2514/3.46085 PG 6 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500004 ER PT J AU YIP, LP FRATELLO, DJ ROBELEN, DB MAKOWIEC, GM AF YIP, LP FRATELLO, DJ ROBELEN, DB MAKOWIEC, GM TI WIND-TUNNEL AND FLIGHT TESTS OF A DELTA-WING REMOTELY PILOTED VEHICLE SO JOURNAL OF AIRCRAFT LA English DT Article AB At the request of the United States Marine Corps, an exploratory wind-tunnel and flight-test investigation was conducted by NASA Langley Research Center on the Marine Corps' Exdrone remotely piloted vehicle configuration. Static wind-tunnel tests were conducted to identify and improve the stability and control characteristics of the vehicle. The wind-tunnel tests resulted in several configuration modifications, including increased elevator area, increased vertical tail area and moment arm, increased rudder area and aileron area, the addition of vertical wingtip fins, and the addition of leading-edge droops on the outboard wing panel to improve stall departure resistance. Flight tests showed improved flight characteristics of the modified configuration. RP YIP, LP (reprint author), NASA,LANGLEY RES CTR,DIV FLIGHT APPL,FLIGHT RES BRANCH,HAMPTON,VA 23665, USA. NR 0 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD NOV PY 1991 VL 28 IS 11 BP 728 EP 734 DI 10.2514/3.46089 PG 7 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500008 ER PT J AU ROSSOW, VJ AF ROSSOW, VJ TI PROBE SHAPES FOR STREAMWISE MOMENTUM AND CROSS-STREAM TURBULENCE INTENSITY SO JOURNAL OF AIRCRAFT LA English DT Article AB When the highly turbulent flowfields at the edges of jets, in augmentors, and in other jet-mixing devices are surveyed with conventional pitot probes, the values indicated by the instruments may contain a significant increment brought about by the dynamics of the eddies. Although the influence of turbulence on the measurements is usually negligible in streams where the turbulence level is 1% or less, the effect of turbulence on static and total pressure measurements can be around 20% when the turbulence level exceeds 40%. This paper describes a theoretical study that develops probe shapes that directly measure the time-averaged total pressure based on the streamwise component of the velocity vector to obtain a direct measurement of the streamwise momentum. The difference between the time-averaged pressure indicated by such a probe and one that measures the total head based on the entire velocity vector yields the cross-stream turbulence intensity. RP ROSSOW, VJ (reprint author), NASA,AMES RES CTR,FIXED WING AERODYNAM BRANCH,MOFFETT FIELD,CA 94035, 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 NOV PY 1991 VL 28 IS 11 BP 741 EP 749 DI 10.2514/3.46091 PG 9 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500010 ER PT J AU ROSSOW, VJ AF ROSSOW, VJ TI PROBE SYSTEMS FOR STATIC PRESSURE AND CROSS-STREAM TURBULENCE INTENSITY SO JOURNAL OF AIRCRAFT LA English DT Article AB A recent study of total-pressure probes for use in highly trubulent streams is extended herein by developing probe systems that measure time-averaged static or ambient pressure and turbulence intensity. Arrangements of tubular probes of circular and elliptical cross section are described that measure the pressure at orifices on the sides of the probes to obtain different responses to the cross-stream velocity fluctuations. When the measured data are combined to remove the effect of the presence of the probes on the local pressure, the time-averaged static pressure and the cross-stream components of turbulence intensity can be determined. If a system of total pressure tubes, as described in an accompanying paper, is added to the static pressure group to form a single cluster, redundant measurements are obtained that permit accuracy and consistency checks. RP ROSSOW, VJ (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 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 NOV PY 1991 VL 28 IS 11 BP 750 EP 755 DI 10.2514/3.46092 PG 6 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500011 ER PT J AU GREEN, LL MINECK, RE AF GREEN, LL MINECK, RE TI WALL INTERFERENCE ASSESSMENT CORRECTION FOR TRANSONIC AIRFOIL DATA SO JOURNAL OF AIRCRAFT LA English DT Article AB Two sets of transonic airfoil data were obtained from the same model tested in both porous, planar-wall and solid, shaped-wall wind tunnels. The published data agree resonably well with each other but differ significantly from two-dimensional, free-air Navier-Stokes calculations for the same airfoil. An existing computational wall interference assessment/correction (WIAC) procedure was applied to the porous- and shaped-wall data sets. The WIAC corrections generally improve the correlation between the two data sets. Simultaneously, the WIAC corrections also generally improve the correlation between the data and the Navier-Stokes calculations. RP GREEN, LL (reprint author), NASA,LANGLEY RES CTR,CAB FLDMD,M-S 128,HAMPTON,VA 23665, 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 NOV PY 1991 VL 28 IS 11 BP 774 EP 780 DI 10.2514/3.46095 PG 7 WC Engineering, Aerospace SC Engineering GA GR265 UT WOS:A1991GR26500014 ER PT J AU GRIFFITHS, DJ BUETTNER, DJ TSOU, P AF GRIFFITHS, DJ BUETTNER, DJ TSOU, P TI EFFECT OF VOID-SIZE DISTRIBUTION ON THE HUGONIOT STATE AT LOW SHOCK PRESSURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID POROUS MATERIALS; MODEL AB In most theoretical and experimental investigations into the shock response of underdense solid media, the influence of the medium's mesostructure on the resulting pressure and degree of compaction has not been taken into account. In typical cases examined, shock pressures are well in excess of 1 GPa and this approach is clearly justified. However, at low pressures, calculations show that the distribution of void sizes can affect the final state achieved upon shocking the medium from a given initial porosity. This paper analyzes the response of porous aluminum to low pressure shocking and demonstrates a dependence of the final shocked state on the distribution of void sizes. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP GRIFFITHS, DJ (reprint author), OREGON STATE UNIV,DEPT PHYS,CORVALLIS,OR 97331, USA. NR 21 TC 4 Z9 4 U1 3 U2 4 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 NOV 1 PY 1991 VL 70 IS 9 BP 4790 EP 4796 DI 10.1063/1.349045 PG 7 WC Physics, Applied SC Physics GA GN971 UT WOS:A1991GN97100017 PM 11538709 ER PT J AU CEBULA, RP DELAND, MT HILSENRATH, E SCHLESINGER, BM HUDSON, RD HEATH, DF AF CEBULA, RP DELAND, MT HILSENRATH, E SCHLESINGER, BM HUDSON, RD HEATH, DF TI INTERCOMPARISONS OF THE SOLAR IRRADIANCE MEASUREMENTS FROM THE NIMBUS-7 SBUV, THE NOAA-9 AND NOAA-11 SBUV/2, AND THE STS-34 SSBUV INSTRUMENTS - A PRELIMINARY-STUDY SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID ULTRAVIOLET IRRADIANCE AB Solar irradiance measurements in the spectral range 160-400 nm at approximately 0.15-0.20 nm intervals and at 1 nm resolution have been made by Solar Backscatter Ultraviolet (SBUV) series instruments continually since November 1978. Solar irradiance data from the Nimbus-7 SBUV satellite instrument, the SBUV/2 instruments on the NOAA-9 and NOAA-11 satellites, and the October 1989 flight (STS-34) of the Shuttle SBUV (SSBUV) instrument are presented and intercompared. Uncertainties in the instruments' absolute and long-term radiometric calibrations, which vary among the four instruments, are discussed. Comparisons of the initial, or 'day 1', solar spectra from the four instruments shows agreements to within approximately 10%, with spectral biases on the order of +/- 4%. Irradiances measured by the two NOAA instruments and SSBUV agree to within about 5% overall from 270 to 360 nm, with spectral biases on the order of about +/- 2%; the Nimbus-7 SBUV irradiances are an additional 5-10% lower in this region than those measured by the other three instruments. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 21771. SCI APPLICAT RES,LANHAM,MD 20706. RP CEBULA, RP (reprint author), ST SYST CORP,4400 FORBES BLVD,LANHAM,MD 20706, USA. RI Hudson, Robert/F-4506-2010 NR 15 TC 10 Z9 11 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD NOV-DEC PY 1991 VL 53 IS 11-12 BP 993 EP 997 DI 10.1016/0021-9169(91)90044-8 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX802 UT WOS:A1991GX80200002 ER PT J AU PAP, JM DONNELLY, RF HUDSON, HS ROTTMAN, GJ WILLSON, RC AF PAP, JM DONNELLY, RF HUDSON, HS ROTTMAN, GJ WILLSON, RC TI VARIABILITY OF SOLAR ULTRAVIOLET IRRADIANCE SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID FLUX AB A model of solar Lyman alpha irradiance developed by multiple linear regression analysis, including the daily values and 81-day running means of the full disk equivalent width of the Helium line at 1083 nm, predicts reasonably well both the short- and long-term variations observed in Lyman alpha. In contrast, Lyman alpha models calculated from the 10.7 cm radio flux overestimate the observed variations in the rising portion and maximum period of solar cycle, and underestimates them during solar minimum. We show models of Lyman alpha based on the He line equivalent width and 10.7 cm radio flux for those time intervals when no satellite observations exist, namely back to 1974 and after April 1989, when the measurements of the Solar Mesosphere Satellite were terminated. C1 NOAA,SEL,BOULDER,CO 80303. UNIV CALIF SAN DIEGO,SAN DIEGO,CA 92109. JET PROP LAB,PASADENA,CA 91103. UNIV COLORADO,LASP,BOULDER,CO 80309. RP PAP, JM (reprint author), UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309, USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD NOV-DEC PY 1991 VL 53 IS 11-12 BP 999 EP 1003 DI 10.1016/0021-9169(91)90045-9 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX802 UT WOS:A1991GX80200003 ER PT J AU FARRUGIA, CJ DUNLOP, MW ELLIOTT, S FREEMAN, MP BALOGH, A COWLEY, SWH LEPPING, RP SIBECK, DG AF FARRUGIA, CJ DUNLOP, MW ELLIOTT, S FREEMAN, MP BALOGH, A COWLEY, SWH LEPPING, RP SIBECK, DG TI MULTIPOINT OBSERVATIONS OF PLANAR INTERPLANETARY MAGNETIC-FIELD STRUCTURES SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID NOVEMBER 1; MAGNETOSPHERIC COMPRESSION; SOLAR-WIND AB We present interplanetary magnetic field (IMF) data made on 1 November 1984 by three spatially well-separated spacecraft in the solar wind: the IMP 8, AMPTE-UKS and -CCE spacecraft. The IMF measured by each of the spacecraft is found to consist of a multiplicity of structures within which the magnetic field varies in parallel planes. The orientations of these planes at the three spacecraft locations are similar. The planes are inclined at a large angle to the ecliptic, and they lie almost perpendicular to the nominal Parker spiral direction in the ecliptic. Intercomparisons of the measurements at the various spacecraft show that the IMF features at one spacecraft are clearly reproduced at another with, however, time delays required for the propagation of signals. Using these time delays and the mutual separations of the spacecraft, we infer that the structures are convecting with the ambient flow. Simultaneous observations made downstream of the bow shock in the magnetosheath reveal that the magnetosheath magnetic field, too, is planar. However, the plane of maximum variation of the magnetosheath magnetic field is sheared with respect to the corresponding plane in the solar wind, and the field now ties approximately tangential to the magnetopause. Finally, our observations are contrasted to another IMF configuration showing gross departures from the nominal Parker spiral orientation: magnetic clouds. C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20707. RP FARRUGIA, CJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI dunlop, malcolm/F-1347-2010; Sibeck, David/D-4424-2012 NR 16 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD NOV-DEC PY 1991 VL 53 IS 11-12 BP 1039 EP 1047 DI 10.1016/0021-9169(91)90050-H PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX802 UT WOS:A1991GX80200008 ER PT J AU NAGPAL, OP RAGHAVARAO, R AF NAGPAL, OP RAGHAVARAO, R TI ON THE WAVE FORCING OF THE SEMIANNUAL ZONAL WIND OSCILLATION SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article ID MIDDLE ATMOSPHERE; PLANETARY WAVES; MODEL AB The mean zonal wind in the tropical atmosphere is characterised by the presence of two dominant long-period oscillations namely the quasi-biennial oscillation (QBO) between 18-35 km altitude and the semi-annual oscillation (SAO) at altitudes between 35 and 60 km. These oscillations cannot be accounted for on the basis of thermal forcing, as is the case for the annual oscillation (AO) in extratropical regions. It is now established that wave forcing in the troposphere is responsible for the generation of both the QBO and SAO through wave-mean flow interactions. Though the nature of the wave modes required to explain the QBO are known with some certainty, the same cannot be said for the wave modes in the upper stratosphere which are responsible for producing the SAO. This paper gives observational evidence for the presence of rather long period waves (22-60 days) at upper stratospheric heights (30-60 km), particularly during the winter months over Indian tropical stations. The implications of these wave modes in producing the easterly phase of the SAO are discussed. A 2-D dynamic wind model has been used to simulate both the westerly and easterly phases of the SAO. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP UNIV DELHI, DEPT PHYS, DELHI 110007, INDIA. NR 26 TC 10 Z9 10 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD NOV-DEC PY 1991 VL 53 IS 11-12 BP 1181 EP 1193 DI 10.1016/0021-9169(91)90069-J PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX802 UT WOS:A1991GX80200027 ER PT J AU BILITZA, D AF BILITZA, D TI SOLAR-TERRESTRIAL MODELS AT THE NATIONAL SPACE SCIENCE DATA CENTER SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article AB The National Space Science Data Center (NSSDC) and World Data Center A for Rockets and Satellites (WDC-A-R&S) has a long record of participation in the worldwide efforts to establish and improve empirical models for the different regions of the solar-terrestrial environment. The center maintains a unique archive of solar-terrestrial models and related applications software, described in a recently published models catalog. The software packages are distributed on tape, diskette, and on-line on the Space Physics Analysis Network (SPAN). Four of the most frequently requested models (IRI, MSIS/CIRA, IGRF, AE-8/AP-8) can also be accessed and run on the NSSDC Online Documentation and Information Service (NODIS) account, which can be reached from any SPAN node. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,GREENBELT,MD 20771. NR 12 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD NOV-DEC PY 1991 VL 53 IS 11-12 BP 1207 EP 1211 DI 10.1016/0021-9169(91)90072-F PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GX802 UT WOS:A1991GX80200030 ER PT J AU ZANDER, R RINSLAND, CP EHHALT, DH RUDOLPH, J DEMOULIN, P AF ZANDER, R RINSLAND, CP EHHALT, DH RUDOLPH, J DEMOULIN, P TI VERTICAL COLUMN ABUNDANCES AND SEASONAL CYCLE OF ACETYLENE, C2H2, ABOVE THE JUNGFRAUJOCH STATION, DERIVED FROM IR SOLAR OBSERVATIONS SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE ACETYLENE; ATMOSPHERIC COMPOSITION; SOLAR OBSERVATIONS ID NONMETHANE HYDROCARBONS; C2-C5 HYDROCARBONS; LIGHT-HYDROCARBONS; ABSORPTION-SPECTRA; CLOUD TRANSPORT; TROPOSPHERE; ETHANE; IDENTIFICATION; STRATOSPHERE; PROFILES AB Monthly mean total vertical column abundances of acetylene have been determined from series of infrared solar spectra recorded at the Jungfraujoch station, Switzerland, between June 1986 and April 1991. The data have been obtained by nonlinear least-squares fittings of the nu-5 band R19 transition of C2H2 at 776.0818 cm-1. The average of 22 monthly mean total vertical columns if C2H2 retrieved during that time interval of almost 5 years was found to be equal to (1.81 +/- 0.12) x 10(15) molec/cm2, which corresponds to an average mixing ratio of (0.22 +/- 0.013) ppbv (parts per billion by volume) in a troposphere extending from the altitude of the station (3.58 km), up to 10.5 km. Despite the large variability found from year to year, a least-squares sine fit to the data reveals a seasonal variation with an amplitude of about +/- 40% of the mean; the maximum occurs during mid-winter and the minimum in the summer. The present results are compared critically with similar in-situ data found in the literature. A sinusoidal fit to all such free troposphere measurements made in-situ between 30-degrees-N and 60-degrees-N indicates good agreement in shape and phase with the seasonal variation derived above the Jungfraujoch, but their average column abundance, 2.3 x 10(15) molec/cm2, is about 30% higher; this difference is explained on the basis of non-upwelling meteorological conditions generally prevailing during ground-based remote solar observations. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST ATMOSPHAR CHEM, W-5170 JULICH 1, GERMANY. RP ZANDER, R (reprint author), UNIV LIEGE, INST ASTROPHYS, B-4000 LIEGE, BELGIUM. NR 42 TC 15 Z9 15 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD NOV PY 1991 VL 13 IS 4 BP 359 EP 372 DI 10.1007/BF00057752 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA HK297 UT WOS:A1991HK29700004 ER PT J AU MA, Q TIPPING, RH AF MA, Q TIPPING, RH TI A FAR WING LINE-SHAPE THEORY AND ITS APPLICATION TO THE WATER CONTINUUM ABSORPTION IN THE INFRARED REGION .1. SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID STATISTICAL-THEORY; ROTATIONAL BANDS; SPECTRAL REGION; VAPOR AB A theory is presented for the calculation of the continuous absorption due to the far wing contributions of allowed lines. The theory is based on the quasistatic approximation for the far wing limit and the binary collision approximation of one absorber molecule and one bath molecule. In line space, the motion of the dipole moment of the absorber molecule, determined by the time displacement Liouville operator related to the total Hamiltonian of the absorber molecule and the bath molecule, is approximately expressed as the ordered product of two time displacement Liouville operators, one related to the intermolecular potential and the other to the unperturbed Hamiltonian. Using a Laplace transformation, the spectral density is expressed in terms of a Cauchy integral whose integrand is a product of two resolvent operators corresponding to the interaction and to the unperturbed Hamiltonian, respectively. After isolating the effects of the bath variables, the spectral density and subsequently the absorption coefficient are expressed in terms of the individual line coupling functions, or the individual line shape functions. By using two average line shape functions instead of the individual ones, the expression of the absorption coefficient closely matches empirical models. The validity of the present theory is discussed, and some numerical results of the water continuum absorption in the infrared region are presented for comparison with experimental data. A good agreement in both the manitude and the temperature dependence of the absorption coefficients is obtained. Some further extensions and applications of the present theory are also discussed briefly. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV ALABAMA,DEPT PHYS & ASTRON,TUSCALOOSA,AL 35487. RP MA, Q (reprint author), COLUMBIA UNIV,CTR STUDY GLOBAL HABITABIL,NEW YORK,NY 10025, USA. NR 27 TC 52 Z9 57 U1 0 U2 3 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 NOV 1 PY 1991 VL 95 IS 9 BP 6290 EP 6301 DI 10.1063/1.461549 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GL753 UT WOS:A1991GL75300011 ER PT J AU STALLCOP, JR PARTRIDGE, H LEVIN, E AF STALLCOP, JR PARTRIDGE, H LEVIN, E TI RESONANCE CHARGE-TRANSFER, TRANSPORT CROSS-SECTIONS, AND COLLISION INTEGRALS FOR N+(3P)-N(4S0) AND O+(4S0)-O(3P) INTERACTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article AB N2+ and O2+ potential energy curves have been constructed by combining measured data with the results from electronic structure calculations. These potential curves have been employed to determine accurate charge exchange cross sections, transport cross sections, and collision integrals for ground state N+ -N and O+ -O interactions. The cross sections have been calculated from a semiclassical approximation to the scattering using our computer code that fits a spline curve through the discrete potential data and incorporates the proper long-range behavior of the interaction forces. The charge exchange cross sections are slightly smaller than the values we reported previously using an asymptotic approximation and also agree well with the results of beam measurements at high energies. The collision integrals are tabulated for a broad range of temperatures 250-100 000 K and are intended to reduce the uncertainty in the values of the transport properties of nonequilibrium air, particularly at high temperatures. C1 RES INST ADV COMP SCI,MOFFETT FIELD,CA 94035. RP STALLCOP, JR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 28 TC 79 Z9 79 U1 0 U2 3 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 NOV 1 PY 1991 VL 95 IS 9 BP 6429 EP 6439 DI 10.1063/1.461563 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GL753 UT WOS:A1991GL75300025 ER PT J AU MINNIS, P YOUNG, DF HARRISON, EF AF MINNIS, P YOUNG, DF HARRISON, EF TI EXAMINATION OF THE RELATIONSHIP BETWEEN OUTGOING INFRARED WINDOW AND TOTAL LONGWAVE FLUXES USING SATELLITE DATA SO JOURNAL OF CLIMATE LA English DT Article AB The relationship between narrowband and broadband thermal radiances is explored to determine the accuracy of outgoing longwave radiation derived from narrowband data. Infrared window ( 10.2-12.2-mu-m) data from the Geostationary Operational Environmental Satellite (GOES) are correlated with longwave (5.0-50.0-mu-m) data from the Earth Radiation Budget Experiment (ERBE). A simple quadratic fit between the narrowband and longwave fluxes results in standard errors of 4.4%-5.3% for data that are matched closely in time and space. The use of matched regional flux data with temporal differences up to 59 minutes yields standard errors of 4.1%-5.4%. About 30% of the error may be attributed to limb darkening and spatial and temporal differences in the matched fluxes. The relationship shows a statistically significant dependence on the relative humidity of the atmosphere above the radiating surface. Although this dependency accounts for only about 1% of the standard error, it reduces the monthly mean regional errors by more than 10%. Data taken over land produced a relationship slightly different from data taken over water. The differences appear to be primarily due to daytime heating of the land surface. Cloud amount and cloud-top height also influence the narrowband-broadband relationship. Inclusion of these statistically relevant parameters does not affect the standard errors. but it reduces the monthly mean regional errors by 9%. Better humidity and temperature data and knowledge of cloud microphysics may be required to further improve the relationship. Using the best global fits, it is concluded that the monthly mean outgoing flux may be determined with an rms uncertainty of 1.7% using a single infrared window channel with coincident cloud and humidity data. The atmospheric structure that dictates the infrared-longwave relationship does nol vary randomly: it changes with climate regimes. Thus, the errors resulting from using the global fits tend to be biases concentrated in certain geographical areas. This areal biasing dampens the utility of the narrowband data for monitoring the climatic-scale changes in the longwave flux. Regressions performed on a region-by-region basis eliminate most of the monthly mean regional bias errors. Thus, the regional regressions may be useful for short-term studies requiring high temporal sampling. Because of varying atmospheric conditions, regional regressions require continual calibration with broadband instruments, thereby limiting their utility for longer-term climate applications. RP MINNIS, P (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665, USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 0 TC 32 Z9 32 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 NOV PY 1991 VL 4 IS 11 BP 1114 EP 1133 DI 10.1175/1520-0442(1991)004<1114:EOTRBO>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GW765 UT WOS:A1991GW76500005 ER PT J AU NOEVER, DA AF NOEVER, DA TI DIFFUSIVE SLIP AND SURFACE TRANSPORT-PROPERTIES SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article ID BOUNDARY-CONDITION RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES-76,HUNTSVILLE,AL 35812, USA. NR 22 TC 3 Z9 3 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 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD NOV PY 1991 VL 147 IS 1 BP 186 EP 191 DI 10.1016/0021-9797(91)90146-Y PG 6 WC Chemistry, Physical SC Chemistry GA GL371 UT WOS:A1991GL37100018 ER PT J AU CACIOPPO, E PUSEY, ML AF CACIOPPO, E PUSEY, ML TI THE SOLUBILITY OF THE TETRAGONAL FORM OF HEN EGG-WHITE LYSOZYME FROM PH 4.0 TO 5.4 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID AMMONIUM-SULFATE; PROTEIN; CRYSTALLIZATION; CRYSTAL; GROWTH AB Hen egg white lysozyme solubilities in the presence of the tetragonal crystal form have been determined. Conditions investigated cover the pH range 4.0 to 5.4, varying from 2.0% to 7.0% NaCl concentrations and from 4 to 25-degrees-C. In all instances, the solubilities were found to increase with temperature and decrease with increasing salt concentration. The effects of pH were more complex, showing a decreasing solubility with increasing pH at low salt concentration and an increasing solubility with increasing pH at high salt concentration. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,BIOPHYS BRANCH,E576,HUNTSVILLE,AL 35812. NR 22 TC 194 Z9 196 U1 0 U2 21 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 NOV PY 1991 VL 114 IS 3 BP 286 EP 292 DI 10.1016/0022-0248(91)90043-5 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA GT795 UT WOS:A1991GT79500004 ER PT J AU RAO, MN GARRISON, DH BOGARD, DD BADHWAR, G MURALI, AV AF RAO, MN GARRISON, DH BOGARD, DD BADHWAR, G MURALI, AV TI COMPOSITION OF SOLAR-FLARE NOBLE-GASES PRESERVED IN METEORITE PARENT BODY REGOLITH SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ENERGETIC PARTICLES; NEON COMPOSITION; LUNAR SOIL; FAYETTEVILLE; HELIUM; ARGON AB The isotopic composition (long-term average) of solar flare (SF) Ne has been determined by three isotope correlation techniques applied to data measured on chemically etched pyroxene separates prepared from the Kapoeta meteorite, which is known to contain implanted solar gases. The SF Ne-20/Ne-22 ratio obtained is 11.6 +/- 0.2 and confirms previous determinations of this SF ratio in lunar and meteoritic samples. The same SF Ne composition is also obtained by applying an ordinate intercept technique to the same data set. The ordinate intercept technique was also applied to the Ar and He data, on which the three - isotope correlation technique cannot be applied. The isotopic composition of SF Ar and SF He so obtained are Sf Ar-36/Ar-38 = 4.9 +/- 0.1 and SF He-4/He-3 = 3800 +/- 200, which are significantly different from the solar wind (SW) Ar and SW He values of approximately 5.35 and approximately 2500, respectively. Correlation between Ne-20/Ne-22 and Ar-36/Ar-38 for the same data set also gives a similar SF Ar-36/Ar-38 ratio of 4.8 +/- 0.2. The determined SF He, Ne and Ar isotopic ratios differ from those in SW by 52%, 17% and 9%, respectively, but the elemental compositions of He-4/Ar-36 and Ne-20/Ar-36 do not show obvious differences between SF and SW. The concentration of the SF component in Kapoeta pyroxenes is approximately 20% that of the SW component, which is orders of magnitude higher than expected from SW and SF proton flux measurements. Variations in elemental and isotopic composition of He, Ne and Ar in SF relative to SW are found to correlate well with a (Z/A)2 dependence, indicating a rigidity-dependent particle spectrum in solar flares. C1 PHYS RES LAB,DIV GEOPHYS,AHMEDABAD 380009,GUJARAT,INDIA. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77258. LUNAR & PLANETARY INST,HOUSTON,TX 77058. RP RAO, MN (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 37 TC 35 Z9 35 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 NOV 1 PY 1991 VL 96 IS A11 BP 19321 EP 19330 DI 10.1029/91JA01948 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700006 PM 11538179 ER PT J AU OSHEROVICH, VA BENSON, RF AF OSHEROVICH, VA BENSON, RF TI THE LOWER SUBSIDIARY DIFFUSE PLASMA RESONANCES AND THE CLASSIFICATION OF RADIO EMISSIONS BELOW THE PLASMA FREQUENCY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FREE ELECTROMAGNETIC-FIELDS; CYCLOTRON-HARMONIC WAVES; IONOSPHERIC PLASMA; CYLINDRICAL OSCILLATIONS; PHYSICAL NATURE; TURBULENCE; MAGNETOSPHERE; SATELLITE; ALTITUDE; SEQUENCE AB The diffuse ionospheric resonances D(n), stimulated by topside sounders, have been studied for over 2 decades. These resonances are observed below the plasma frequency f(N) between the harmonics of the electron gyrofrequency f(H). The D(n) resonances are often accompanied by upper and lower subsidiary branches. The present paper concentrates on the classification of diffuse resonances, one motivation being the possible application to the interpretation of naturally occurring radio emissions in the magnetosphere. Osherovich has shown that the D(n)1/2 resonances are characterized by a nonequally spaced spectrum of frequencies f(D)n = f(D)s(n) (n = 1, 2, 3, and 4), where f(D)s = 0.95(f(N)f(H))1/2, and that the upper subsidiary resonances D(n)+ can be considered as upper hybrid resonances of D(n) with frequencies given by f(D)n+ = (f(D)n2 + f(H)2)1/2. This classification is here extended to include the lower subsidiary resonances D(n)- (n = 1, 2, 3, and 4), and it is shown that their frequencies are related to f(D)n and f(H) by the expression f(D)n- = (f(D)n2 - f(H)2)1/2. This result is based on a combination of previously published data and newly scaled ionograms from the Alouette 2 and ISIS 1 topside sounder experiments. RP OSHEROVICH, VA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693,GREENBELT,MD 20771, USA. NR 34 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 NOV 1 PY 1991 VL 96 IS A11 BP 19331 EP 19341 DI 10.1029/91JA01961 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700007 ER PT J AU COLE, KD AF COLE, KD TI ON THE LIMIT OF FIELD-ALIGNED CURRENT INTENSITY IN THE POLAR MAGNETOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article AB Field-aligned current (FAC) is here defined by 4-pi-j = alpha-B, where alpha is constant along a magnetic field line. The upper limit value of alpha in the polar magnetosphere, possible source regions of the strongest FAC and the relationship of them to some auroral and ionospheric irregularity cross-field scale sizes are discussed. Cross-field dimensions of the strongest FAC are related to the gyroradii of source particles (O+, He++, He+, H+, e) in the current-generating region. It is suggested that experimental determination, and mapping of the values of alpha, may assist with the search for the generators of such currents in near-Earth space including in the nearby solar wind. We associate the upper limit of alpha with the breakup of FAC systems. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY ATMOSPHERES BRANCH,GREENBELT,MD 20771. NR 20 TC 2 Z9 2 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 NOV 1 PY 1991 VL 96 IS A11 BP 19389 EP 19396 DI 10.1029/91JA01862 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700012 ER PT J AU STOREY, LRO LEFEUVRE, F PARROT, M CAIRO, L ANDERSON, RR AF STOREY, LRO LEFEUVRE, F PARROT, M CAIRO, L ANDERSON, RR TI INITIAL SURVEY OF THE WAVE DISTRIBUTION-FUNCTIONS FOR PLASMASPHERIC HISS OBSERVED BY ISEE-1 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-DENSITY EXPERIMENT; VLF HISS; ELF HISS; 6-COMPONENT MEASUREMENTS; MAGNETOSPHERIC CHORUS; ELECTROMAGNETIC-WAVES; EARTHS MAGNETOSPHERE; GEOS-1; FREQUENCY; EMISSIONS AB Multicomponent ELF/VLF wave data from the ISEE 1 satellite have been analyzed with the aim of identifying the generation mechanism of plasmaspheric hiss, and especially of determining whether it involves wave propagation on cyclic trajectories. The data were taken from four passes of the satellite, of which two were close to the geomagnetic equatorial plane and two were farther from it; all four occurred during magnetically quiet periods. The principal method of analysis was calculation of the wave distribution functions. The waves appear to have been generated over a wide range of altitudes within the plasmasphere, and most, though not all, of them were propagating obliquely with respect to the Earth's magnetic field. On one of the passes near the equator, some wave energy was observed at small wave normal angles, and these waves may have been propagating on cyclic trajectories. Even here, however, obliquely propagating waves were predominant, a finding that is difficult to reconcile with the classical quasi-linear generation mechanism or its variants. The conclusion is that another mechanism, probably nonlinear, must have been generating most of the hiss observed on these four passes. C1 CNRS,EQUIPE RECH PHYS MATH MODELISAT & SIMULAT,F-45071 ORLEANS 2,FRANCE. CNRS,PHYS & CHIM ENVIRONNEMENT LAB,F-45071 ORLEANS 2,FRANCE. UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. RP STOREY, LRO (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,CODE 9302,GREENBELT,MD 20771, USA. NR 77 TC 32 Z9 32 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 NOV 1 PY 1991 VL 96 IS A11 BP 19469 EP 19489 DI 10.1029/91JA01828 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700019 ER PT J AU PEREDO, M STERN, DP AF PEREDO, M STERN, DP TI ON THE POSITION OF THE NEAR-EARTH NEUTRAL SHEET - A COMPARISON OF MAGNETIC MODEL PREDICTIONS WITH EMPIRICAL FORMULAS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID PLASMA SHEET; FIELD; TAIL; MAGNETOTAIL; SHAPE AB A detailed comparison of the near-Earth neutral sheet position according to several approximations has been made. In particular, two empirical formulas for the neutral sheet location, recently derived from AMPTE/CCE data, have been compared with the corresponding positions derived from Tsyganenko's magnetic field models. Cylindrical coordinates referenced to the geodipole have been used, and the position of the neutral sheet has been identified by the reversal of the radial component of the magnetic field. The analysis reveals that in the region -9 R(E) less-than-or-equal-to X(GSM) less-than-or-equal-to -5 R(E), \Y(GSM)\ less-than-or-equal-to 5 R(E), close agreement exists between the empirical formulas and the Tsyganenko models. Furthermore, the Tsyganenko models provide a representation for the neutral sheet position in the transition region between near-Earth and distant tail models. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP PEREDO, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,ST SYST CORP,CODE 695,GREENBELT,MD 20771, USA. NR 9 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD NOV 1 PY 1991 VL 96 IS A11 BP 19521 EP 19524 DI 10.1029/91JA02133 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700024 ER PT J AU CANE, HV RICHARDSON, IG HARVEY, K AF CANE, HV RICHARDSON, IG HARVEY, K TI FILAMENT DISAPPEARANCES AND ASSOCIATED SHOCKS OF MAY 1979 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Note ID CORONAL MASS EJECTIONS; INTERPLANETARY SHOCKS; PARTICLE EVENTS; DISTURBANCES; SPACECRAFT; ERUPTIONS AB In late May 1979 a shock was seen at each of two locations separated by about 90-degrees in heliolongitude and at about the same time. A shock was detected near the Earth, and a shock was detected at Helios 1 when it was off the Sun's west limb. Some authors have considered that these shocks were part of the same event, which originated with a filament disappearance near 65-degrees-W. We discuss the observations which show that a large complex filament, extending from 20-degrees-W to 70-degrees-W, disappeared in several Places, probably generating more than one shock. The shock detected near Earth was probably associated with a filament section which disappeared near the central meridian. If this is the case, then the interplanetary scintillation observations of this time period can be explained without invoking highly anisotropic shock propagation. C1 SOLAR PHYS RES CORP,TUCSON,AZ 85718. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. OI Richardson, Ian/0000-0002-3855-3634 NR 13 TC 10 Z9 10 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 NOV 1 PY 1991 VL 96 IS A11 BP 19525 EP 19528 DI 10.1029/91JA01979 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM857 UT WOS:A1991GM85700025 ER PT J AU BYUN, KW BONG, W GELLER, D SUNKEL, J AF BYUN, KW BONG, W GELLER, D SUNKEL, J TI ROBUST H-INFINITY CONTROL DESIGN FOR THE SPACE STATION WITH STRUCTURED PARAMETER UNCERTAINTY SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB A robust H infinity control design methodology and its application to a Space Station attitude and momentum control problem are presented. This new approach incorporates nonlinear, multiparameter variations in the state-space formulation of H infinity control theory. An application of this robust H infinity control synthesis technique to the Space Station control problem yields a remarkable result in stability robustness with respect to the moments-of-inertia variation of about 73% in one of the structured uncertainty directions. The performance and stability of this new robust H infinity controller for the Space Station are compared to those of other controllers designed using a standard linear quadratic regulator synthesis technique. C1 ARIZONA STATE UNIV,DEPT MECH & AEROSP ENGN,TEMPE,AZ 85287. NASA,LYNDON B JOHNSON SPACE CTR,DIV AVION,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,DIV MISSION PLANNING & ANAL,HOUSTON,TX 77058. RI Geller, David/N-3425-2014 NR 16 TC 24 Z9 26 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 1991 VL 14 IS 6 BP 1115 EP 1122 DI 10.2514/3.20765 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600004 ER PT J AU BYUN, KW BONG, W SUNKEL, J AF BYUN, KW BONG, W SUNKEL, J TI ROBUST NON-MINIMUM-PHASE COMPENSATION FOR A CLASS OF UNCERTAIN DYNAMIC-SYSTEMS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID H-INFINITY; FEEDBACK-SYSTEMS; SENSITIVITY AB This paper presents robust control synthesis techniques for uncertain dynamical systems subject to structured parameter perturbation. Both classical and H infinity control synthesis techniques are investigated. Most H infinity-related control techniques are not directly concerned with the structured parameter perturbation. In this paper, however, a new way of incorporating the parameter uncertainty in the robust H infinity control design is explored. A generic model of uncertain dynamical systems is used to illustrate the design methodologies developed in this paper. It is shown that, for a certain class of noncollocated structural control problems, use of either technique results in non-minimum-phase compensation. C1 ARIZONA STATE UNIV,DEPT MECH & AEROSP ENGN,TEMPE,AZ 85287. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 27 TC 6 Z9 6 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 NOV-DEC PY 1991 VL 14 IS 6 BP 1191 EP 1199 DI 10.2514/3.20774 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600013 ER PT J AU FENNELL, RE ADAMS, WM CHRISTHILF, DM AF FENNELL, RE ADAMS, WM CHRISTHILF, DM TI PARAMETER INSENSITIVE CONTROL UTILIZING EIGENSPACE METHODS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID EIGENSTRUCTURE ASSIGNMENT; MULTIVARIABLE SYSTEMS; ROBUST; OPTIMIZATION; FEEDBACK; DESIGN AB An eigenspace assignment approach to the design of parameter insensitive control laws for linear multivariable systems is Presented. The control design scheme utilizes constrained optimization techniques to exploit the flexibility in eigenvector assignments to reduce control system sensitivity to changes in system parameters while maintaining performance and robustness requirements; it thus provides a systematic approach for choosing values for eigensystem design variables. In a design example, the methods are applied to the problem of symmetric flutter suppression in an aeroelastic vehicle. In this example, the flutter mode is sensitive to changes in dynamic pressure and eigenspace methods are used to reduce the parametric sensitivity of a stabilizing minimum energy/linear quadratic regulator controller and associated observer. Numerical results indicate that the methods provide feedback control laws that make the stability of the nominal closed-loop system less sensitive to changes in dynamic pressure while maintaining acceptable control power constraints. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. RP FENNELL, RE (reprint author), CLEMSON UNIV,DEPT MATH SCI,CLEMSON,SC 29634, USA. NR 20 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 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 1991 VL 14 IS 6 BP 1208 EP 1214 DI 10.2514/3.20776 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600015 ER PT J AU HOADLEY, ST KARPEL, M AF HOADLEY, ST KARPEL, M TI APPLICATION OF AEROSERVOELASTIC MODELING USING MINIMUM-STATE UNSTEADY AERODYNAMIC APPROXIMATIONS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Various control analysis, design, and simulation techniques for aeroservoelastic applications require the equations of motion to be cast in a linear time-invariant state-space form. Unsteady aerodynamic forces have to be approximated as transfer functions of the Laplace variable in order to put them in this framework. For the minimum-state method, the number of augmenting states representing the unsteady aerodynamics is a function only of the number of denominator roots in the approximation. Results are shown of applying various approximation enhancements (including optimization, mode, and frequency-dependent weighting of the tabular data, and constraint selection) of a minimum-state formulation of the equations of motion of an active flexible wing wind-tunnel model. The results demonstrate that good mathematical models can be developed which have a factor of 10 fewer augmenting aerodynamic equations than more traditional approaches. This reduction facilitates the design of lower-order control systems, analysis of control system performance, and near real-time simulation of aeroservoelastic phenomena. C1 TECHNION ISRAEL INST TECHNOL,DEPT AEROSP ENGN,IL-32000 HAIFA,ISRAEL. RP HOADLEY, ST (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,AEROSERVOELAST BRANCH,MAIL STOP 243,HAMPTON,VA 23665, USA. NR 20 TC 15 Z9 15 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 NOV-DEC PY 1991 VL 14 IS 6 BP 1267 EP 1276 DI 10.2514/3.20783 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600022 ER PT J AU DECOU, AB AF DECOU, AB TI ORBITAL DYNAMICS OF THE HANGING TETHER INTERFEROMETER SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note C1 CALTECH,JET PROP LAB,SUMMER FAC FELLOWSHIP PROGRAM,PASADENA,CA 91109. RP DECOU, AB (reprint author), NO ARIZONA UNIV,ENGN,FLAGSTAFF,AZ 86011, USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 1991 VL 14 IS 6 BP 1309 EP 1311 DI 10.2514/3.20788 PG 3 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600027 ER PT J AU LIN, CA CHENG, VHL AF LIN, CA CHENG, VHL TI STATISTICAL LINEARIZATION FOR MULTIINPUT MULTIOUTPUT NONLINEARITIES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note C1 NASA,AMES RES CTR,AIRCRAFT GUIDANCE & NAVIGAT BRANCH,MOFFETT FIELD,CA 94035. RP LIN, CA (reprint author), NATL CHIAO TUNG UNIV,DEPT CONTROL ENGN,HSINCHU,TAIWAN. NR 9 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 1991 VL 14 IS 6 BP 1315 EP 1318 DI 10.2514/3.20791 PG 4 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA GW566 UT WOS:A1991GW56600030 ER PT J AU RINSLAND, CP SMITH, MAH DEVI, VM BENNER, DC AF RINSLAND, CP SMITH, MAH DEVI, VM BENNER, DC TI MEASUREMENTS OF LORENTZ-BROADENING COEFFICIENTS AND PRESSURE-INDUCED LINE SHIFT COEFFICIENTS IN THE NU-2-BAND OF D2 O-16 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID DIODE-LASER MEASUREMENTS; WATER-VAPOR; NU-2 BAND; N2-BROADENING COEFFICIENTS; AIR; (H2O)-O-16; NITROGEN; TEMPERATURE; HALFWIDTHS; ABSORPTION C1 COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23185. RP RINSLAND, CP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665, USA. NR 22 TC 15 Z9 15 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD NOV PY 1991 VL 150 IS 1 BP 173 EP 183 DI 10.1016/0022-2852(91)90200-T PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA GL971 UT WOS:A1991GL97100012 ER PT J AU LANE, HW KEITH, RE STRAHAN, S WHITE, MT AF LANE, HW KEITH, RE STRAHAN, S WHITE, MT TI THE EFFECT OF DIET, EXERCISE AND 7,12-DIMETHYLBENZ(A)ANTHRACENE ON FOOD-INTAKE, BODY-COMPOSITION AND CARCASS ENERGY-LEVELS IN VIRGIN FEMALE BALB/C MICE SO JOURNAL OF NUTRITION LA English DT Article DE AIN-76A DIET; TREADMILL; BODY COMPOSITION; MICE; 7,12-DIMETHYLBENZ(A)ANTHRACENE ID MOUSE MAMMARY TUMORIGENESIS; HIGH-FAT DIET; RATS; CARCINOGENESIS; RESTRICTION; GROWTH AB This study investigated the effect of diet, exercise and 7,12-dimethylbenz(a)anthracene (DMBA), a mammary-tumor carcinogen, on food intake, energy consumption, body weight and body composition in virgin female BALB/c mice. Interactions were examined among three diet conditions (standard AIN-76A, restricted AIN-76A and high fat AIN-76A diet), two exercise conditions (with and without treadmill exercise) and two treatment conditions (carcinogen or corn oil sham). Mice were randomized to one of 12 groups at 6 wk of age; beginning at 8 wk of age, all mice received either 7,12-dimethylbenz(a)anthracene (1 mg/0.2 mL corn oil) or 0.2 mL of corn oil via gastric tube once each week for six consecutive weeks. Exercise in a rotating-drum treadmill was initiated at 10 wk of age and was increased to a final rate of 6 m/min for 60 min, 5 d/wk. Mice were killed at 24 wk of age, confirmed to be tumor-free and analyzed for protein and fat content, from which body energy was calculated. Energy consumption was highest in the standard diet-fed groups followed by the high fat diet-fed groups and the restricted diet-fed groups. The groups fed the standard diet and restricted diet had similar body weight and carcass energy. Exercise or DMBA treatment generally reduced food consumption, energy intake, body weight and carcass energy. In summary, diet, exercise and DMBA all had pronounced effects on energy consumption, which in turn affected body composition. These treatments may influence expression of breast cancer via their effects on body composition. C1 AUBURN UNIV,ALABAMA AGR EXPT STN,DEPT NUTR & FOODS,AUBURN,AL 36849. RP LANE, HW (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV MED SCI,BIOMED OPERAT & RES BRANCH,MAIL CODE SD4,HOUSTON,TX 77058, USA. RI Biguzzi, Felipe/E-4724-2015 NR 31 TC 11 Z9 11 U1 0 U2 0 PU AMER INST NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0022-3166 J9 J NUTR JI J. Nutr. PD NOV PY 1991 VL 121 IS 11 BP 1876 EP 1882 PG 7 WC Nutrition & Dietetics SC Nutrition & Dietetics GA GM655 UT WOS:A1991GM65500021 PM 1941195 ER PT J AU LANE, HW TEER, P KEITH, RE WHITE, MT STRAHAN, S AF LANE, HW TEER, P KEITH, RE WHITE, MT STRAHAN, S TI REDUCED ENERGY-INTAKE AND MODERATE EXERCISE REDUCE MAMMARY-TUMOR INCIDENCE IN VIRGIN FEMALE BALB/C MICE TREATED WITH 7,12-DIMETHYLBENZ(A)ANTHRACENE SO JOURNAL OF NUTRITION LA English DT Article DE HIGH FAT DIET; RESTRICTED DIET; MICE; EXERCISE; MAMMARY TUMORS ID ESSENTIAL FATTY-ACID; DIETARY-FAT; RATS; TUMORIGENESIS; CARCINOGENESIS; RESTRICTION; ENHANCEMENT; FOOD AB This study evaluated the concurrent effects of diet (standard AIN-76A, restricted AIN-76A and high-fat diet) and moderate rotating-drum treadmill exercise on the incidence of 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas in virgin female BALB/cMed mice free of murine mammary tumor virus. Exercise significantly reduced food consumption in the groups fed the standard diet and high fat diet. Although food consumption varied widely, final body weight was similar in all groups. Exercise had no effect on mammary tumor incidence in the standard diet-fed groups (without exercise, 47%; with exercise, 45%); however, exercise reduced mammary tumor incidence in the other groups as follows: restricted diet/no exercise, 28%; restricted diet/with exercise, 13%; high fat diet/no exercise, 31%; high fat diet/with exercise, 19%. Restricting food intake reduced mammary tumor incidence, but had no effect on body weight. Although energy intake was related to mammary tumor incidence, neither body weight nor dietary fat predicted tumor incidence. C1 AUBURN UNIV,DEPT NUTR & FOODS,AUBURN,AL 36849. AUBURN UNIV,DEPT PATHOBIOL,AUBURN,AL 36849. RP LANE, HW (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV MED SCI,BIOMED OPERAT & RES BRANCH,MAIL CODE SD4,HOUSTON,TX 77058, USA. NR 25 TC 23 Z9 23 U1 0 U2 0 PU AMER INST NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0022-3166 J9 J NUTR JI J. Nutr. PD NOV PY 1991 VL 121 IS 11 BP 1883 EP 1888 PG 6 WC Nutrition & Dietetics SC Nutrition & Dietetics GA GM655 UT WOS:A1991GM65500022 PM 1941196 ER PT J AU ZELEZNIK, FJ AF ZELEZNIK, FJ TI THERMODYNAMIC PROPERTIES OF THE AQUEOUS SULFURIC-ACID SYSTEM TO 350-K SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article AB Experimental measurements for aqueous sulfuric acid and its related pure, solid phases have been thermodynamically analyzed and correlated as a function of temperature and composition from pure water to pure acid. The pure phases included anhydrous sulfuric acid, five of its hydrates and ice. Experimental data which were used in the correlation included measurements of the enthalpy of dilution, both solution and pure phase heat capacities, electromotive force and solution freezing points. The correlation yielded mutually consistent expressions fo for the Gibbs energy of each phase and these functions generally reproduce the experimental data to +/- 0.75 percent. The Gibbs energy functions of the pure solid phases were used to generate tables of their thermodynamic properties from 0 K to the melting points. The Gibbs energy function for aqueous sulfuric acid was used to produce tables of both integral and partial molar solution properties as a function of sulfuric acid mole fraction every 50-degrees from 200 to 350 K. RP ZELEZNIK, FJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 86 Z9 86 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD NOV-DEC PY 1991 VL 20 IS 6 BP 1157 EP 1200 PG 44 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA GX451 UT WOS:A1991GX45100002 ER PT J AU GLAZMAN, RE SROKOSZ, MA AF GLAZMAN, RE SROKOSZ, MA TI EQUILIBRIUM WAVE SPECTRUM AND SEA STATE BIAS IN SATELLITE ALTIMETRY SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GENERATED GRAVITY-WAVES; SURFACE ELEVATION; GEOMETRY; FIELD; RANGE AB For a well-developed sea at equilibrium with a constant wind, the energy-containing range of the wavenumber spectrum for wind-generated gravity waves is approximated by a generalized power law beta(U2/g)(2-mu)k(-4+2-mu)Y(k, theta), where Y is the angular spread function and mu can be interpreted as a fractal codimension of a small surface patch. Dependence of mu on the wave age, xi = C0/U, is estimated, and the "Phillips constant," beta, along with the low-wavenumber boundary, k0, of the inertial subrange are studied analytically based on the wave action and energy conservation principles. The resulting expressions are employed to evaluate various non-Gaussian statistics of a weakly nonlinear sea surface, which determine the sea state bias in satellite altimetry. The locally accelerated decay of the spectral density function in a high-wavenumber dissipation subrange is pointed out as an important factor of wave dynamics and is shown to be also highly important in the geometrical optics treatment of the sea state bias. The analysis is carried out in the approximation of a unidirectional wave field and confined to the case of a well-developed sea characterized by xi > 1. C1 INST OCEANOG SCI,DEACON LAB,RSADU,WORMLEY,SURREY,ENGLAND. RP GLAZMAN, RE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 40 TC 19 Z9 20 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD NOV PY 1991 VL 21 IS 11 BP 1609 EP 1621 DI 10.1175/1520-0485(1991)021<1609:EWSASS>2.0.CO;2 PG 13 WC Oceanography SC Oceanography GA GW421 UT WOS:A1991GW42100001 ER PT J AU NALLASAMY, M GROENEWEG, JF AF NALLASAMY, M GROENEWEG, JF TI UNSTEADY BLADE-SURFACE PRESSURES ON A LARGE-SCALE ADVANCED PROPELLER - PREDICTION AND DATA SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID LEADING-EDGE VORTEX; EULER EQUATIONS; FLOWS AB An unsteady, three-dimensional Euler analysis technique was used to compute the flowfield of an advanced propeller operating at an angle of attack. The predicted blade-pressure waveforms for an angular inflow of 3 deg were compared with wind-tunnel data at two Mach numbers, 0.5 and 0.2. For an inflow Mach number of 0.5, the predicted pressure response is in fair agreement with data: the predicted phases of the waveforms are in close agreement with data, whereas the magnitudes are underpredicted. At the low Mach number of 0.2 (takeoff), the numerical solution shows the formation of a leading-edge vortex that is in qualitative agreement with measurements. However, the highly nonlinear pressure response measured on the blade suction surface is not captured in the present inviscid analysis. C1 NASA,LEWIS RES CTR,DIV PROP SYST,PROPELLOR & ACOUST TECHNOL BRANCH,CLEVELAND,OH 44135. RP NALLASAMY, M (reprint author), SVERDRUP TECHNOL INC,DEPT AEROMECH,LEWIS RES CTR GRP,BROOK PK,OH 44142, USA. 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 1991 VL 7 IS 6 BP 866 EP 872 DI 10.2514/3.23403 PG 7 WC Engineering, Aerospace SC Engineering GA GU117 UT WOS:A1991GU11700003 ER PT J AU MANSKI, D MARTIN, JA AF MANSKI, D MARTIN, JA TI EVALUATION OF INNOVATIVE ROCKET ENGINES FOR SINGLE-STAGE EARTH-TO-ORBIT VEHICLES SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 24TH JOINT PROPULSION CONF CY JUL 11-13, 1988 CL BOSTON, MA SP AMER INST AERONAUT & ASTRONAUT, AMER SOC MECH ENGINEERS, SOC AUTOMOT ENGINEERS, AMER SOC ENGN EDUC AB Computer models of rocket engines and single-stage-to-orbit vehicles that were developed by the authors have been combined. The resulting code consists of engine mass and performance, trajectory, and vehicle sizing models. The engine mass model includes equations for each subsystem and describes their dependence on various propulsion parameters. The engine performance model consists of multidimensional sets of theoretical propulsion properties and a complete thermodynamic analysis of the engine cycle. The vehicle analyses include an optimized trajectory analysis, mass estimation, and vehicle sizing. A vertical-takeoff, horizontal-landing, single-stage, winged, manned, fully reusable vehicle was selected for the evaluations. Hydrogen, methane, propane, and dual-fuel engines were studied with staged-combustion, gas-generator, dual-bell, and dual-expander cycles. Mixture ratio, chamber pressure, nozzle exit pressure, liftoff acceleration, and dual-fuel propulsive parameters were optimized. C1 NASA,LANGLEY RES CTR,DIV SPACE SYST,HAMPTON,VA 23665. RP MANSKI, D (reprint author), DLR GERMAN AEROSP RES ESTAB,INST CHEM PROP,W-7101 LAMPOLDSHAUSEN,GERMANY. NR 7 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 1991 VL 7 IS 6 BP 929 EP 937 DI 10.2514/3.23411 PG 9 WC Engineering, Aerospace SC Engineering GA GU117 UT WOS:A1991GU11700012 ER PT J AU HOCHSTEIN, JI KORAKIANITIS, TP PATAG, AE CHATO, DJ AF HOCHSTEIN, JI KORAKIANITIS, TP PATAG, AE CHATO, DJ TI MODELING OF IMPULSIVE PROPELLANT REORIENTATION SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The impulsive propellant reorientation process is modeled using the ECLIPSE code. Brief descriptions of the process and the computational model are presented. Code validation is documented via comparison to experimental data for small-scale tanks. Predictions of reorientation performance are presented for two tanks designed for use in flight experiments and for a proposed full-scale orbit transfer vehicle tank. A dimensionless parameter is developed to correlate reorientation performance in geometrically similar tanks. Its success is demonstrated. C1 NASA,LEWIS RES CTR,CRYOGEN FLUID MANAGEMENT TECHNOL OFF,CLEVELAND,OH 44135. RP HOCHSTEIN, JI (reprint author), WASHINGTON UNIV,MECH ENGN,ST LOUIS,MO 63130, USA. RI Chato, David/B-2698-2013 OI Chato, David/0000-0003-2990-0646 NR 11 TC 7 Z9 7 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 NOV-DEC PY 1991 VL 7 IS 6 BP 938 EP 945 DI 10.2514/3.23412 PG 8 WC Engineering, Aerospace SC Engineering GA GU117 UT WOS:A1991GU11700013 ER PT J AU HAH, C SELVA, RJ AF HAH, C SELVA, RJ TI NAVIER-STOKES ANALYSIS OF FLOW AND HEAT-TRANSFER INSIDE HIGH-PRESSURE-RATIO TRANSONIC TURBINE BLADE ROWS SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A detailed numerical study of the flow and the heat transfer inside high-pressure-ratio transonic/supersonic turbine blade rows is described. A high-order upwinding relaxation method is used to solve the Reynolds-averaged Navier-Stokes equation inside three different turbine blade rows. A two-equation turbulence model with a low-Reynolds-number modification is used to describe turbulent shear stress and turbulent heat flux. The numerical results are compared with available experimental data on two-dimensional geometries. It is found that very complex flow phenomena near the trailing edge of transonic turbine blade rows can be very well predicted numerically, and the method can be used in the development of new designs for HP turbines. C1 CRAY RES INC,MENDOTA HTS,MN 55120. GE,CTR RES & DEV,SCHENECTADY,NY 12345. RP HAH, C (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135, USA. NR 13 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 NOV-DEC PY 1991 VL 7 IS 6 BP 990 EP 996 DI 10.2514/3.23418 PG 7 WC Engineering, Aerospace SC Engineering GA GU117 UT WOS:A1991GU11700020 ER PT J AU SAVAGE, M LEWICKI, DG AF SAVAGE, M LEWICKI, DG TI TRANSMISSION OVERHAUL AND COMPONENT REPLACEMENT PREDICTIONS USING WEIBULL AND RENEWAL THEORY SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID LIFE AB Two methods of estimating the time between transmission overhauls and the number of replacement components needed were presented. The first method assumes replacement of all components during an overhaul of a failed transmission (full replacement method). The second method assumes replacement of failed components only (partial replacement method). Both methods assume the transmission components follow a two-parameter Weibull failure distribution. Renewal theory was presented to estimate the number of component replacements in a transmission for both methods. For the partial replacement method, renewal theory was used with a the individual component life predictions to estimate the number of component replacements needed and the transmission time between overhauls. For the full replacement method, renewal theory was used with a transmission system life model to estimate the number of replacement transmissions needed and the transmission time between overhauls. Confidence statistics were applied to both methods to improve the statistical estimate of sample behavior. A transmission example was presented to illustrate use of both methods. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SAVAGE, M (reprint author), UNIV AKRON,MECH ENGN,AKRON,OH 44325, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 1991 VL 7 IS 6 BP 1049 EP 1054 DI 10.2514/3.23426 PG 6 WC Engineering, Aerospace SC Engineering GA GU117 UT WOS:A1991GU11700028 ER PT J AU MLYNCZAK, MG DRAYSON, SR AF MLYNCZAK, MG DRAYSON, SR TI RAPID COMPUTATION OF THE RADIATIVE ABSORPTION RATE IN THE NU-3-MODE OF MESOSPHERIC AND LOWER THERMOSPHERIC OZONE SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID TERRESTRIAL MIDDLE ATMOSPHERE; INFRARED LIMB EMISSION AB We have developed an algorithm to calculate rapidly and accurately the rate (photons-molecule-1-sec-1) at which the ozone nu-3 fundamental band obsorbs i.r. radiation in the terrestrial upper mesosphere and lower thermosphere. Accurate knowledge of this rate is essential for studies of non-LTE processes in ozone and for estimating ozone concentrations from measurements of non-LTE i.r. emission from the middle atmosphere. In our algorithm, the 1252 ozone nu-3 fundamental lines that govern radiative absorption are divided into 13 groups according to line strength. The absorption rate due to a single line representative of the mean line strength of each group is then calculated. The total absorption rate is obtained by multiplying the absorption rate for each mean line by the total number of lines within each group and adding the resultant products for all 13 groups. We also incorporate several other approximations, such as assuming that each mean line has the same Voigt line shape, which significantly reduces the number of Voigt function evaluations. The algorithm preserves the accuracy of detailed, time-consuming line-by-line approaches while requiring only a fraction of the CPU time of such techniques. C1 UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. RP MLYNCZAK, MG (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,THEORET STUDIES BRANCH,MAIL STOP 401B,HAMPTON,VA 23665, USA. RI Mlynczak, Martin/K-3396-2012 NR 12 TC 8 Z9 8 U1 0 U2 1 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 NOV PY 1991 VL 46 IS 5 BP 463 EP 471 DI 10.1016/0022-4073(91)90050-Z PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA GR458 UT WOS:A1991GR45800013 ER PT J AU WAHLS, DM FARMER, JT SLEIGHT, DW AF WAHLS, DM FARMER, JT SLEIGHT, DW TI STRUCTURAL DYNAMIC PERFORMANCE OF A GEOSTATIONARY MICROWAVE RADIOMETER SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB HIS synoptic addresses the on-orbit structural performance of a low-frequency microwave radiometer (LFMR) for Earth science applications. The LFMR is an instrument aboard a geostationary platform as part of the proposed program Mission to Planet Earth. The present study 1 quantifies the ability of the LFMR structure to retain its design shape subject to a representative onboard disturbance. It includes a description of the LFMR concept, the structural model, the assumed on-orbit disturbances, and the analyses performed to quantify the antenna's resulting root mean squared (rms) surface roughness, pointing error, and defocus. These errors are measured based on the locations of the nodes of the distorted antenna relative to the ideal (error-free) antenna node positions. The electromagnetic performance of an antenna can be adversely affected by numerous factors, among which is the geometric displacement of the antenna's various structural components from their optimum positions. Minimizing the overall surface roughness, pointing error, and defocus is of extreme importance for high-precision reflector antennas such as the LFMR. Reference 1 describes in detail a sequential approach for assessing the ability of an antenna structure to retain its geometric shape subject to a dynamic disturbance. C1 UNIV ILLINOIS,SPACE STN,FREEDOM OFF,URBANA,IL 61801. RP WAHLS, DM (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,HAMPTON,VA 23665, USA. NR 12 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 NOV-DEC PY 1991 VL 28 IS 6 BP 617 EP 618 DI 10.2514/3.26290 PG 2 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300001 ER PT J AU MITCHELTREE, RA AF MITCHELTREE, RA TI PARAMETRIC STUDY OF DISSOCIATION AND IONIZATION MODELS AT 12 KILOMETERS 2ND SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Thermochemical nonequilibrium solution dependence on available models for the chemical reaction rates is examined. Solutions from the Kang and Dunn reaction rate set, the Park rate set of 1987, and the Park rate set of 1991 are compared. The blunt-nosed, axisymmetric geometry considered is a 60-deg sphere cone with nose radius of 1.07 m and circular aft skirt. The nonequilibrium test case is 12-km/s entry into the Earth's atmosphere at 80-km altitude. The model variations are implemented into the Langley Aerothermodynamics Upwind Relaxation Algorithm code. New, high-temperature, equilibrium-constant curve fits proposed by Gupta are also examined, and Hansen's new formulation for the rate controlling temperature for the dissociation reactions is compared with existing formulations for this parameter. Although variations in the reaction rates have no effect on the surface pressure distribution and little effect on the convective heating, the effect on degree of ionization and radiative heating can be a factor of 3. RP MITCHELTREE, RA (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 15 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 1991 VL 28 IS 6 BP 619 EP 627 DI 10.2514/3.26291 PG 9 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300002 ER PT J AU RILEY, CJ DEJARNETTE, FR AF RILEY, CJ DEJARNETTE, FR TI ENGINEERING CALCULATIONS OF 3-DIMENSIONAL INVISCID HYPERSONIC FLOWFIELDS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SURFACE AB An approximate solution technique has been developed for three-dimensional, inviscid, hypersonic flows. The method uses Maslen's explicit pressure equation and the assumption of approximate stream surfaces in the shock layer. This approximation represents a simplification of Maslen's asymmetric method. The solution procedure involves iteratively changing the shock shape in the subsonic-transonic region until the correct body shape is obtained. Beyond this region, the shock surface is determined by using a marching procedure. Results are presented for a paraboloid and elliptic cone at angle of attack. Calculated surface pressure distributions, shock shapes, and property profiles are compared with experimental data and finite difference solutions of the Euler equations. Comparisons of the results of the present method with experimental data and detailed predictions are very good. Since the present method provides a very rapid computational procedure, it can be used for parametric or preliminary design applications. One useful application would be to incorporate a heating procedure for aerothermal studies. C1 N CAROLINA STATE UNIV,DEPT MECH & AEROSP ENGN,RALEIGH,NC 27695. RP RILEY, CJ (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,AEROTHERMODYNAM BRANCH,MS 366,HAMPTON,VA 23665, USA. NR 23 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 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 1991 VL 28 IS 6 BP 628 EP 635 DI 10.2514/3.26292 PG 8 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300003 ER PT J AU WILHITE, AW BUSH, LB CRUZ, CI LEPSCH, RA MORRIS, WD STANLEY, DO WURSTER, KE AF WILHITE, AW BUSH, LB CRUZ, CI LEPSCH, RA MORRIS, WD STANLEY, DO WURSTER, KE TI ADVANCED TECHNOLOGIES FOR ROCKET SINGLE-STAGE-TO-ORBIT VEHICLES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A single-stage-to-orbit vertical takeoff/horizontal landing rocket vehicle was studied to determine (he benefits of advanced technology. Advanced technologies that were included in the study were variable mixture ratio oxygen/hydrogen rocket engines and materials, structures, and subsystem technologies currently being developed in the National Aero-Space Plane program. The application of advanced technology results in an 85% reduction in vehicle dry weight. Compared to an all-air-breathing horizontal takeoff/horizontal landing vehicle using the same advanced technologies and mission requirements, the rocket vehicle is lighter in dry weight and has fewer subsystems. To increase reliability and safety, operational features were included in the rocket vehicle: robust subsystems, 5% additional margin, no slush hydrogen, fail operational with an engine out, and a crew escape module. The resulting vehicle grew in dry weight, but was still lower in dry weight than the air-breathing vehicle. RP WILHITE, AW (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,VEHICLE ANAL BRANCH,HAMPTON,VA 23665, USA. NR 11 TC 4 Z9 4 U1 1 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 NOV-DEC PY 1991 VL 28 IS 6 BP 646 EP 651 DI 10.2514/3.26294 PG 6 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300005 ER PT J AU WADA, BK FANSON, JL CHEN, GS AF WADA, BK FANSON, JL CHEN, GS TI USING ADAPTIVE STRUCTURES TO ENABLE FUTURE MISSIONS BY RELAXING GROUND TEST REQUIREMENTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Future NASA missions will require large space structures that must maintain accurate surface tolerances for up to 20 years; most flight programs require a ground test verification of the hardware. Because of the influence of gravity, the current state-of-the-art ground test technology cannot accurately determine whether the hardware complies with the requirements. The incorporation of adaptive structures into the spacecraft will enable a relaxation of the ground test requirements necessary to validate the hardware for flight. This paper describes the challenges in testing large precision structures, adaptive structures, the data establishing the current state of the art in ground testing, and the utilization of adaptive structures to alleviate the ground lest requirements. RP WADA, BK (reprint author), CALTECH,JET PROP LAB,BLDG 157,ROOM 507,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 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 NOV-DEC PY 1991 VL 28 IS 6 BP 663 EP 669 DI 10.2514/3.26297 PG 7 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300008 ER PT J AU BRODY, AR ELLIS, SR AF BRODY, AR ELLIS, SR TI ACCELERATION AND PULSE CONTROL IN SIMULATED SPACECRAFT DOCKING MANEUVERS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NASA,AMES RES CTR,ADV DISPLAYS & CONTROLS LAB,MOFFETT FIELD,CA 94035. RP BRODY, AR (reprint author), STERLING SOFTWARE,HUMAN FACTORS AEROSP ENVIRONM TASK,MS 262-2,PALO ALTO,CA 94303, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 1991 VL 28 IS 6 BP 728 EP 730 DI 10.2514/3.26306 PG 3 WC Engineering, Aerospace SC Engineering GA HA093 UT WOS:A1991HA09300017 ER PT J AU DAVIS, S AF DAVIS, S TI LOW-DISPERSION FINITE-DIFFERENCE METHODS FOR ACOUSTIC-WAVES IN A PIPE SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB A new algorithm for computing one-dimensional acoustic waves in a pipe is demonstrated by solving the acoustic equations as an initial-boundary-value problem. Conventional dissipation-free second-order finite difference methods suffer severe phase distortion for grids with less that about ten mesh points per wavelength. Using the signal generated by a piston in a duct as an example, transient acoustic computations are presented using a new compact three-point algorithm which allows about 60% fewer mesh points per wave length. Both pulse and harmonic excitation are considered. Coupling of the acoustic signal with the pipe resonant modes are shown to generate a complex transient wave with rich harmonic content. RP DAVIS, S (reprint author), NASA,AMES RES CTR,FLUID MECH LAB,FLUID DYNAM RES BRANCH,MOFFETT FIELD,CA 94035, USA. NR 10 TC 19 Z9 20 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 NOV PY 1991 VL 90 IS 5 BP 2775 EP 2781 DI 10.1121/1.401874 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA GN734 UT WOS:A1991GN73400043 ER PT J AU BEGAULT, DR AF BEGAULT, DR TI CHALLENGES TO THE SUCCESSFUL IMPLEMENTATION OF 3-D SOUND SO JOURNAL OF THE AUDIO ENGINEERING SOCIETY LA English DT Article ID HEADPHONE SIMULATION; HEAD AB The major challenges for the successful implementation of 3-D audio systems involve minimizing reversals, intracranially heard sound, and localization error for listeners. Designers of 3-D audio systems are faced with additional challenges in data reduction and low-frequency response characteristics. The relationship of the head-related transfer function (HRTF) to these challenges is shown, along with some preliminary psychoacoustic results gathered at NASA-Ames. RP BEGAULT, DR (reprint author), NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS,MOFFETT FIELD,CA 94035, USA. NR 13 TC 32 Z9 33 U1 0 U2 2 PU AUDIO ENGINEERING SOC PI NEW YORK PA 60 E 42ND ST, NEW YORK, NY 10165-2520 SN 0004-7554 J9 J AUDIO ENG SOC JI J. Audio Eng. Soc. PD NOV PY 1991 VL 39 IS 11 BP 864 EP 870 PG 7 WC Acoustics; Engineering, Multidisciplinary SC Acoustics; Engineering GA GR264 UT WOS:A1991GR26400003 ER PT J AU TOTH, RA AF TOTH, RA TI V2 BAND OF (H2O)-O-16 - LINE STRENGTHS AND TRANSITION FREQUENCIES SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID EXCITED VIBRATIONAL-STATE; DIODE-LASER MEASUREMENTS; HYDROGEN FLAME SPECTRA; WATER-VAPOR; ROTATIONAL SPECTRUM; H2O; REGION; CM-1; SPECTROSCOPY; PARAMETERS AB High-resolution spectra of (H2O)-H-2-O-16 were recorded with a Fourier-transform spectrometer covering transitions in the (010)-(000) band from 1066 to 2582 cm-1. The measured line frequencies were used along with additional data taken from studies at microwave and far-infrared frequencies in an analysis to obtain rotational energies of levels in the (000) and (010) states. Measurements of the line strengths were fitted by least squares to a model in which the dipole moment matrix elements were represented by as many as 19 expansion coefficients. The results produced computed line strength values that are in excellent agreement, on the average, with the 874 experimental transitions included in the analysis. These results provide a more accurate representation of the line positions and strengths for the (010)-(000) band than are currently available on the HITRAN absorption line parameter compilation. RP TOTH, RA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 36 TC 189 Z9 189 U1 1 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD NOV PY 1991 VL 8 IS 11 BP 2236 EP 2255 DI 10.1364/JOSAB.8.002236 PG 20 WC Optics SC Optics GA GN918 UT WOS:A1991GN91800002 ER PT J AU TIBERIO, RC PORKOLAB, GA ROOKS, MJ WOLF, ED LANG, RJ LARSSON, A FOROUHAR, S CODY, J WICKS, GW ERDOGAN, T KING, O HALL, DG AF TIBERIO, RC PORKOLAB, GA ROOKS, MJ WOLF, ED LANG, RJ LARSSON, A FOROUHAR, S CODY, J WICKS, GW ERDOGAN, T KING, O HALL, DG TI FACETLESS BRAGG REFLECTOR SURFACE-EMITTING ALGAAS/GAAS LASERS FABRICATED BY ELECTRON-BEAM LITHOGRAPHY AND CHEMICALLY ASSISTED ION-BEAM ETCHING SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 35TH INTERNATIONAL SYMP ON ELECTRON, ION, AND PHOTON BEAMS CY MAY 28-31, 1991 CL SEATTLE, WA SP AMER VACUUM SOC, IEEE, ELECTR DEVICE, OPT SOC AMER ID GAAS AB We report the fabrication and characterization of facetless Bragg reflector surface-emitting AlGaAs/GaAs lasers. Both first-order (120-nm period) and second-order (240-nm period) gratings were fabricated by electron-beam lithography and chemically assisted ion-beam etching (CAIBE). These grating pairs provide the optical feedback of the laser, eliminating the need for cleaved or etched mirror facets. Specifically, this work includes: the fabrication and testing of a variable pitch grating-laser array which demonstrates optical emission peaks with 5-angstrom separation for adjacent lasers; demonstration of facetless Bragg reflector lasers with 120/240-nm grating pairs that show lower threshold currents, higher quantum efficiencies, and improved beam width compared to conventional facetless second-order grating lasers; and a demonstration of grating surface-emitting diode lasers with hybrid first-order and nonresonant, 120/307-nm, grating pairs that produced a directed beam at 45-degrees with respect to the substrate. The fabrication technology and optical performance of these devices are presented. C1 CORNELL UNIV,SCH ELECT ENGN,ITHACA,NY 14853. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV ROCHESTER,INST OPT,ROCHESTER,NY 14627. RP TIBERIO, RC (reprint author), CORNELL UNIV,NATL NANOFABRICAT FACIL,ITHACA,NY 14853, USA. RI Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 16 TC 10 Z9 10 U1 0 U2 1 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 NOV-DEC PY 1991 VL 9 IS 6 BP 2842 EP 2845 DI 10.1116/1.585653 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA GW423 UT WOS:A1991GW42300019 ER PT J AU BONHAM, CD DELLACORTE, C AF BONHAM, CD DELLACORTE, C TI THE APPLICATION OF A COMPUTER-DATA ACQUISITION-SYSTEM TO A NEW HIGH-TEMPERATURE TRIBOMETER SO LUBRICATION ENGINEERING LA English DT Article AB This paper describes two data acquisition computer programs which were developed for a high temperature tribometer, a friction and wear test apparatus. The raw data produced by the tribometer and the methods used to sample that data are explained. In addition, the instrumentation and computer hardware and software are presented. This paper also demonstrates how computer data acquisition was applied to increase convenience and productivity on a high temperature tribometer. RP BONHAM, CD (reprint author), NASA,SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,CLEVELAND,OH 44135, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD NOV PY 1991 VL 47 IS 11 BP 907 EP 923 PG 17 WC Engineering, Mechanical SC Engineering GA GN019 UT WOS:A1991GN01900004 ER PT J AU ARYA, VK AF ARYA, VK TI FINITE-ELEMENT ANALYSIS OF STRUCTURAL COMPONENTS BY USING VISCOPLASTIC MODELS WITH APPLICATION TO A COWL LIP PROBLEM SO MATERIALS AT HIGH TEMPERATURES LA English DT Article DE FINITE ELEMENT ANALYSIS; VISCOPLASTIC MODEL; HYPERSONIC ENGINE AB The viability of advanced viscoplastic models for nonlinear finite element analyses of structural components is investigated. Several uniaxial and a multiaxial problem are analysed by using the finite element implementation of Freed's viscoplastic model. Good agreement between the experimental and calculated uniaxial results validates the finite element implementation and gives confidence to apply it to more complex multiaxial problems. A comparison of results for a sample structural component (the cowl lip of a hypersonic engine inlet) with the earlier elastic, elastic-plastic, and elastic-plastic-creep analyses available in the literature shows that the elastic-viscoplastic analyses yield more reasonable stress and strain distributions. Finally, the versatility of the finite-element-based solution technology presented here is demonstrated by applying it to another viscoplastic model. RP ARYA, VK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0960-3409 J9 MATER HIGH TEMP JI Mater. High Temp. PD NOV PY 1991 VL 9 IS 4 BP 201 EP 208 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HG662 UT WOS:A1991HG66200004 ER PT J AU VARY, A AF VARY, A TI SPECIAL ISSUE PRAISED SO MATERIALS EVALUATION LA English DT Letter RP VARY, A (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD NOV PY 1991 VL 49 IS 11 BP 1363 EP 1363 PG 1 WC Materials Science, Characterization & Testing SC Materials Science GA GP111 UT WOS:A1991GP11100001 ER PT J AU FREED, AD AF FREED, AD TI TEXS ROUGH RIDE SO MECHANICAL ENGINEERING LA English DT Letter RP FREED, AD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0025-6501 J9 MECH ENG JI Mech. Eng. PD NOV PY 1991 VL 113 IS 11 BP 6 EP & PG 0 WC Engineering, Mechanical SC Engineering GA GN834 UT WOS:A1991GN83400008 ER PT J AU BERTERO, GA HOFMEISTER, WH ROBINSON, MB BAYUZICK, RJ AF BERTERO, GA HOFMEISTER, WH ROBINSON, MB BAYUZICK, RJ TI CONTAINERLESS PROCESSING AND RAPID SOLIDIFICATION OF NB-SI ALLOYS IN THE NIOBIUM-RICH EUTECTIC RANGE SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID MODEL AB Containerless processing and rapid solidification techniques were used to process Nb-Si alloys in the Nb-rich eutectic range. Electromagnetically levitated drops were melted and subsequently splat quenched from different temperatures. A variety of eutectic morphologies was obtained as a function of the degree of superheating or undercooling of the drops prior to splatting. Metallic glass was observed only in drops quenched from above the melting temperature. Microstructures of splats deeply undercooled prior to quenching were very fine and uniform. These results are discussed in terms of classic nucleation theory concepts and the expected heat evolution at different regions of the splat during the rapid quenching process. The locations of the coupled-zone boundaries for the alpha-Nb + Nb3Si eutectic are also suggested. C1 VANDERBILT UNIV,DEPT MAT SCI & ENGN,NASHVILLE,TN 37235. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP BERTERO, GA (reprint author), STANFORD UNIV,DEPT MAT SCI & ENGN,STANFORD,CA 94305, USA. OI Hofmeister, William/0000-0002-4145-7061 NR 20 TC 26 Z9 27 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD NOV PY 1991 VL 22 IS 11 BP 2713 EP 2721 DI 10.1007/BF02851366 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA GP092 UT WOS:A1991GP09200019 ER PT J AU BERTERO, GA HOFMEISTER, WH ROBINSON, MB BAYUZICK, RJ AF BERTERO, GA HOFMEISTER, WH ROBINSON, MB BAYUZICK, RJ TI CONTAINERLESS PROCESSING AND RAPID SOLIDIFICATION OF NB-SI ALLOYS OF HYPEREUTECTIC COMPOSITION SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID PHASE AB Niobium-silicon alloys from 21 to 27 at. pct Si were rapidly solidified employing a combination of electromagnetic levitation and splat-quenching techniques. Levitated liquid drops were overheated or undercooled to different temperatures in the electromagnetic levitation field and subsequently released into a splat-quenching apparatus. Some undercooled drops were allowed to solidify in the coil. Analytical scanning (SEM) and transmission electron microscopy (TEM) as well as X-ray diffraction were used to characterize the microstructures of the processed samples. In the range of compositions studied, the splat-quenched drops always formed the tetragonal Nb3Si phase directly from the liquid. On the other hand, drops solidified in the coil were characterized by the presence of the primary intermetallic Nb5Si3 and the absence of both peritectic Nb3Si and the equilibrium eutectic. In these cases, a metastable alpha-Nb + beta-Nb5Si3 eutectic formed. The cubic A15 Nb3Si structure was not observed in any of these experiments. The results are discussed in terms of possible metastable configurations of the Nb-Si phase diagram as well as concepts of nucleation and growth kinetics applied to the Nb3Si and Nb5Si3 intermetallics. C1 VANDERBILT UNIV,DEPT MAT SCI & ENGN,NASHVILLE,TN 37235. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP BERTERO, GA (reprint author), STANFORD UNIV,DEPT MAT SCI & ENGN,STANFORD,CA 94305, USA. OI Hofmeister, William/0000-0002-4145-7061 NR 18 TC 17 Z9 18 U1 1 U2 5 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD NOV PY 1991 VL 22 IS 11 BP 2723 EP 2732 DI 10.1007/BF02851367 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA GP092 UT WOS:A1991GP09200020 ER PT J AU WAGNER, JA SHENOY, RN AF WAGNER, JA SHENOY, RN TI THE EFFECT OF COPPER, CHROMIUM, AND ZIRCONIUM ON THE MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF AL-ZN-MG-CU ALLOYS SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Note ID STRESS-CORROSION SUSCEPTIBILITY; QUENCH SENSITIVITY; FRACTURE C1 ANALYT SERV & MAT INC,HAMPTON,VA 23666. RP WAGNER, JA (reprint author), NASA,LANGLEY RES CTR,MET MAT BRANCH,HAMPTON,VA 23665, USA. NR 30 TC 35 Z9 41 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD NOV PY 1991 VL 22 IS 11 BP 2809 EP 2817 DI 10.1007/BF02851375 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA GP092 UT WOS:A1991GP09200028 ER PT J AU GEBALLE, TR BURTON, MG ISAACMAN, R AF GEBALLE, TR BURTON, MG ISAACMAN, R TI OBSERVATIONS OF THE 2-MU-M UNIDENTIFIED LINES IN PLANETARY-NEBULAE SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID MOLECULAR-HYDROGEN; SPECTRUM; W51 AB Medium resolution spectra in the K window have been obtained for thirteen planetary nebulae and one compact H II region in order to study the behaviour of the unidentified line at 2.287-mu-m. The wavelengths of this line and the unidentified 2.199-mu-m line have been measured in NGC 7027 at high spectral resolution using a Fabry-Perot interferometer. Based on the interferometric measurements and the lack of correlation of the 2.287-mu-m line with emission in H-2 lines, the unidentified lines are not lines of molecular hydrogen. The 2.287-mu-m line is strongest in medium-high excitation nebulae, and is absent in nebulae of very low and very high excitation, implying that the ionization potential of the parent atom or ion is about 30-40 eV and that the ion itself has an ionization potential of perhaps 40-60 eV. C1 ANGLO AUSTRALIAN OBSERV,EPPING,NSW 2121,AUSTRALIA. GEN SCI CORP,LAUREL,MD 20707. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP GEBALLE, TR (reprint author), JOINT ASTRON CTR,665 KOMOHANA ST,HILO,HI 96720, USA. NR 17 TC 31 Z9 31 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 NOV 1 PY 1991 VL 253 IS 1 BP 75 EP 79 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM879 UT WOS:A1991GM87900010 ER PT J AU JUDGE, PG CARPENTER, KG HARPER, GM AF JUDGE, PG CARPENTER, KG HARPER, GM TI SI-II EMISSION-LINE DIAGNOSTICS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID OUTER ATMOSPHERIC STRUCTURE; OSCILLATOR-STRENGTHS; GIANT STARS; QUIET SUN; RR-TEL; SPECTRUM; IUE; CONSTRAINTS; LIMB AB Ratios of Si II UV emission lines in a variety of objects are compared with computations based upon recently published collisional data of Dufton & Kingston. We analyse a high-quality spectrum of alpha-Tau (K5 III) obtained by Carpenter et al. using the G270M mode of the GHRS on the Hubble Space Telescope, in addition to high-dispersion data from Skylab and IUE. Agreement betwen observation and theory is satisfactory for most lines with the exception of ratios within the 3s(2)3p P-2(0) --> 3s3p2 P4 (UV 0.01) multiplier near 2335 angstrom. A blend with a line of Ni ii accounts partially for the discrepancies and solves a problem with Si II] emission measures. However, a further problem remains which suggests that the computed collision strengths for the transitions 3s(2)3p P-2(1/3,3/2)0 --> 3s3p2 P-4(5/2) may be too large by a factor of about 1.5. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV OXFORD,DEPT PHYS THEORET PHYS,OXFORD OX1 3NP,ENGLAND. RP JUDGE, PG (reprint author), NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,POB 3000,BOULDER,CO 80307, USA. RI Carpenter, Kenneth/D-4740-2012 NR 30 TC 15 Z9 15 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 NOV 1 PY 1991 VL 253 IS 1 BP 123 EP 128 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM879 UT WOS:A1991GM87900015 ER PT J AU WICKRAMASINGHE, DT WU, KW AF WICKRAMASINGHE, DT WU, KW TI AN INTERPRETATION OF THE FIELD ALIGNMENT IN AM HERCULIS TYPE SYSTEMS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Note ID LOW-STATE; H0139-68; EMISSION AB The magnetic white dwarfs in AM Herculis type systems are known to have field structures which differ significantly from that of a centred dipole. We use the implied quadrupole asymmetry to explain the observed orientations of the accretion regions relative to the red star. In particular, we present an interpretation of the result that in four systems where two accretion shocks are observed, the region with the weaker magnetic pole is the stronger accretor. C1 AUSTRALIAN NATL UNIV,DEPT MATH,CANBERRA,ACT 2601,AUSTRALIA. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP WICKRAMASINGHE, DT (reprint author), UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721, USA. NR 32 TC 20 Z9 20 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 NOV 1 PY 1991 VL 253 IS 1 BP P11 EP P15 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GM879 UT WOS:A1991GM87900025 ER PT J AU TAO, WK SIMPSON, J SOONG, ST AF TAO, WK SIMPSON, J SOONG, ST TI NUMERICAL-SIMULATION OF A SUBTROPICAL SQUALL LINE OVER THE TAIWAN STRAIT SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; DUAL-DOPPLER DATA; CLOUD CLUSTERS; 3-DIMENSIONAL SIMULATION; VERTICAL TRANSPORT; DEEP CUMULUS; AIR-FLOW; PRECIPITATION; ORGANIZATION; MOMENTUM AB A two-dimensional, time-dependent, and nonhydrostatic numerical cloud model is used to study the development and structure of a subtropical squall line that occurred during TAMEX (Taiwan Area Mesoscale Experiment). The model includes a parameterized ice-phase microphysical scheme and long- and shortwave radiative transfer processes, as well as heat and moisture fluxes from the ocean surface. It was found that dynamic and kinematic structures of this simulated subtropical squall line are quite similar to its counterparts observed in the tropics and midlatitudes. For example, the squall line has a quasi-steady structure with a successive generation of cells at the gust front that propagate rearward relative to the front, the precipitation, and an evaporatively cooled downdraft at low and midlevels. This particular subtropical squall line is also shown to have a distinct midtropospheric rear inflow and a moderate anvil component of the total precipitation. The vertical transport of horizontal momentum, as well as latent heat release by the simulated subtropical squall system and by squall systems that occur in other geographic locations (both simulated and observed), are compared and presented. We also investigate the roles of 1) heat and moisture fluxes from the ocean, 2) longwave radiative cooling, 3) microphysical processes, and 4) presumed mesoscale convergence lifting on the structure and propagation of this subtropical squall line. Among the seven two-dimensional simulations considered, the general structure of the squall system, such as its propagation speed and its "weak-evolution"-type multicell characteristics, do not change significantly in most of the cases. It was found that each process has a different impact on the total surface precipitation over an 8-h simulation time. The order of importance of each process to the total surface precipitation, beginning with the most important, is microphysics, longwave radiative transfer, heat and moisture input from the ocean, and prestorm mesoscale convergence lifting. C1 UNIV CALIF DAVIS,DEPT LAND AIR & WATER RESOURCES,DAVIS,CA 95616. RP TAO, WK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. NR 71 TC 87 Z9 93 U1 2 U2 6 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 NOV PY 1991 VL 119 IS 11 BP 2699 EP 2723 DI 10.1175/1520-0493(1991)119<2699:NSOASS>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GQ910 UT WOS:A1991GQ91000011 ER PT J AU KAISER, MK CALDERONE, JB AF KAISER, MK CALDERONE, JB TI FACTORS INFLUENCING PERCEIVED ANGULAR VELOCITY SO PERCEPTION & PSYCHOPHYSICS LA English DT Article ID SUPERIOR TEMPORAL AREA; MACAQUE MONKEY; EXPANSION CONTRACTION; ROTATION CELLS; DORSAL PART; MOTION; MOVEMENT; DIRECTION; PARALLAX; FIELD AB The assumption that humans are able to perceive and process angular kinematics is critical to many structure-from-motion and optical flow models. The current studies investigate this sensitivity, and examine several factors likely to influence angular velocity perception. In particular, three factors are considered: (1) the extent to which perceived angular velocity is determined by edge transitions of surface elements, (2) the extent to which angular velocity estimates are influenced by instantaneous linear velocities of surface elements, and (3) whether element-velocity effects are related to three-dimensional (3-D) tangential velocities or to two-dimensional (2-D) image velocities. Edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities influenced perceived angular velocity; this bias was related to 2-D image velocity rather than 3-D tangential velocity. Despite these biases, however, judgments were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter was surprisingly good, for rotations both in depth (y-axis) and parallel to the line of sight (z-axis). C1 SAN JOSE STATE UNIV,SAN JOSE,CA 95192. RP KAISER, MK (reprint author), NASA,AMES RES CTR,MAIL STOP 2623,MOFFETT FIELD,CA 94035, USA. NR 20 TC 11 Z9 11 U1 0 U2 1 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0031-5117 J9 PERCEPT PSYCHOPHYS JI Percept. Psychophys. PD NOV PY 1991 VL 50 IS 5 BP 428 EP 434 DI 10.3758/BF03205059 PG 7 WC Psychology; Psychology, Experimental SC Psychology GA GN748 UT WOS:A1991GN74800003 PM 1788031 ER PT J AU BREININGER, DR PROVANCHA, MJ SMITH, RB AF BREININGER, DR PROVANCHA, MJ SMITH, RB TI MAPPING FLORIDA SCRUB JAY HABITAT FOR PURPOSES OF LAND-USE MANAGEMENT SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID GEOGRAPHIC INFORMATION-SYSTEMS; ACCURACY AB Geographical information system (GIS) applications were used to map areas of primary and secondary Florida Scrub Jay habitat on Kennedy Space Center (KSC) using vegetation and soils maps. Data from field studies were used for accuracy assessment and evaluating the importance of mapping classes. Primary habitat accounts for 15 percent of the potential habitat and contained 57 percent of the Florida Scrub Jay population on KSC. Proximity analysis identified potential population centers, which were 44 percent of the potential habitat and contained 86 percent of the population. This study is an example of how remote sensing and GIS applications can provide information for land-use planning, habitat management, and the evaluation of cumulative impacts. RP BREININGER, DR (reprint author), NASA,BIOMED OPERAT & RES OFF,BIONET CORP,KENNEDY SPACE CTR,FL 32899, USA. NR 59 TC 46 Z9 46 U1 2 U2 9 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 NOV PY 1991 VL 57 IS 11 BP 1467 EP 1474 PG 8 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA GL418 UT WOS:A1991GL41800008 ER PT J AU BRIGGS, H AF BRIGGS, H TI A CLEAR VIEW SOUGHT FOR LARGE SPACEBORNE TELESCOPES SO PHOTONICS SPECTRA LA English DT Article RP BRIGGS, H (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAURIN PUBL CO INC PI PITTSFIELD PA BERKSHIRE COMMON PO BOX 1146, PITTSFIELD, MA 01202 SN 0731-1230 J9 PHOTON SPECTRA JI Photon. Spect. PD NOV PY 1991 VL 25 IS 11 BP 199 EP 202 PG 4 WC Optics SC Optics GA GP051 UT WOS:A1991GP05100024 ER PT J AU SCHLOSSER, H FERRANTE, J SMITH, JR AF SCHLOSSER, H FERRANTE, J SMITH, JR TI GLOBAL EXPRESSION FOR REPRESENTING COHESIVE-ENERGY CURVES SO PHYSICAL REVIEW B LA English DT Note ID ULTRASONIC PARAMETERS; BORN MODEL; CHARGE-TRANSFER; HALIDES; CHEMISORPTION; POTENTIALS; MOLECULES; EQUATION; SOLIDS; METALS AB The R dependence of the cohesive energy of partially ionic solids is examined with a two-term generalization of the universal energy relationship consisting of a Coulomb term arising from the valence charge transfer, delta-Z, between the atoms, and a scaled universal energy function, E*(a*), which accounts for the partially covalent character of the bond, and for the repulsion between the atomic cores for small R; a* is a scaled length. Data from NaCl-structure alkali halide crystals are used to test the procedure. We find that this procedure gives a reasonable apportionment of ionic and covalent terms for the alkali halides. Plots of the normalized cohesive-energy curves for Li, Na, K, and Rb halides indicate that they scale within each family and are essentially identical. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. GM CORP,DEPT PHYS,RES LABS,WARREN,MI 48090. RP SCHLOSSER, H (reprint author), CLEVELAND STATE UNIV,DEPT PHYS,CLEVELAND,OH 44115, USA. NR 20 TC 21 Z9 23 U1 1 U2 3 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 NOV 1 PY 1991 VL 44 IS 17 BP 9696 EP 9699 DI 10.1103/PhysRevB.44.9696 PG 4 WC Physics, Condensed Matter SC Physics GA GP267 UT WOS:A1991GP26700066 ER PT J AU MOIN, P SQUIRES, K CABOT, W LEE, S AF MOIN, P SQUIRES, K CABOT, W LEE, S TI A DYNAMIC SUBGRID-SCALE MODEL FOR COMPRESSIBLE TURBULENCE AND SCALAR TRANSPORT SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID FLOWS AB The dynamic subgrid-scle (SGS) model of Germano et al. [Phys. Fluids A 3, 1760 (1991)] is generalized for the large eddy simulation (LES) of compressible flows and transport of a scalar. The model was applied to the LES of decaying isotropic turbulence, and the results are in excellent agreement with experimental data and direct numerical simulations. The expression for the SGS turbulent Prandtl number was evaluated using direct numerical simulation (DNS) data in isotropic turbulence, homogeneous shear flow, and turbulent channel flow. The qualitative behavior of the model for turbulent Prandtl number and its dependence on molecular Prandtl number, direction of scalar gradient, and distance from the wall are in accordance with the total turbulent Prandtl number from the DNS data. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP MOIN, P (reprint author), STANFORD UNIV,CTR TURBULENCE RES,STANFORD,CA 94305, USA. NR 17 TC 653 Z9 666 U1 8 U2 61 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD NOV PY 1991 VL 3 IS 11 BP 2746 EP 2757 DI 10.1063/1.858164 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GL829 UT WOS:A1991GL82900028 ER PT J AU DUBIN, M SOBERMAN, RK AF DUBIN, M SOBERMAN, RK TI COSMOIDS - SOLUTION TO THE PIONEER-10 AND PIONEER-11 METEOROID MEASUREMENT ENIGMA SO PLANETARY AND SPACE SCIENCE LA English DT Article ID EARTHS UPPER-ATMOSPHERE; SMALL COMETS; INTER-PLANETARY; SOLAR-SYSTEM; DUST; SATURN; NEPTUNE; INFLUX; SEARCH; HALLEY AB A theory characterizing interplanetary matter and the zodiacal light has been derived from the dust experiments on the Pioneer 10 and 11 spacecraft to explain the extremely disparate results of the distribution of particles and the zodiacal light measurements. The theory based on these measurements requires a population in the inner solar system of cold meteoroids, cosmoids, composed mainly of volatile molecules, moving in highly eccentric orbits and seldom surviving a single perihelion passage. Impulsive or bursty disruptions from solar heating appears necessary to explain the measured rapid orders of magnitude increases in optical cross section. The integrated scattering from the dispersed material appears to account for nearly all the zodiacal light, with polarization from scattering by micron sized particles. The sublimation time in sunlight opposes the gravitational flux increase expected in approaching the sun. The three Pioneer 10/11 dust experiments were: the Imaging Photopolarimeter (IPP) for the zodiacal light (ZL), the Meteoroid Detection Experiment (MDE) that measured penetrations of 25 (Pioneer 10) and 50 (Pioneer 11) mu-m thick walls of pressurized gas cells, and the Asteroid/Meteoroid Experiment or "Sisyphus" that remotely measured meteoroids from reflected sunlight and ZL between meteoroid "events". No two investigations agreed on the dust distribution and only the IPP could be fitted to the prevailing model of dust spiraling inward from the asteroid belt. MDE data showed a nearly constant flux from 1 to 18 AU! The IPP showed the ZL decreasing between an inverse square and cube rate from 1 to 3.3 AU where it was no longer detectable. The prevailing model has the ZL decrease one power faster than the dust. Sisyphus showed small radial variations from 1 to 3.5 AU where measurements ceased abruptly with the instrument still operating. Sisyphus results were questioned because meteoroid orbits could not be calculated as intended and the ZL as computed from individual meteoroids did not agree with values determined from the ZL mode and from the IPP. Reexamination of the Sisyphus data shows that the instrument measured a population of long period meteoroids, cosmoids, composed primarily of water which dominates the dust distribution. Once the prevailing short period dust model is discounted, the three instruments, measuring cosmoids, are shown to agree. The subsequent measurements from Helios also show evidence of "fluffy" particles with eccentric orbits. This cosmoid population may interact with the outer planets, effecting rings, radial spoke formation and perhaps impulsive radio signatures. C1 UNIV PENN,SCH MED,DEPT ASTRON & ASTROPHYS,PHILADELPHIA,PA 19104. RP DUBIN, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 46 TC 5 Z9 5 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 NOV PY 1991 VL 39 IS 11 BP 1573 EP 1590 DI 10.1016/0032-0633(91)90084-N PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GV339 UT WOS:A1991GV33900010 ER PT J AU ZEBKER, HA VANZYL, JJ AF ZEBKER, HA VANZYL, JJ TI IMAGING RADAR POLARIMETRY - A REVIEW SO PROCEEDINGS OF THE IEEE LA English DT Review ID INVERSE SCATTERING; POLARIZATION; IMAGES; DISCRIMINATION; CLASSIFICATION; CLUTTER AB Conventional imaging radars operating with a single fixed-polarization antenna are being supplanted by the next generation instrument capable of measuring the polarization of the scattered wave for any and all transmit polarizations. Recent developments in radar technology have led to the development of imaging radar polarimeters, that is, radars that are capable of imaging the Earth's surface at any and all possible polarizations through antenna synthesis techniques. The capability enables the complete measurement of a target's polarization properties, thus permitting a much more detailed understanding of the electromagnetic scattering process. Here we review these technological advances, both hardware and algorithmic, and present some sample data sets acquired using these techniques. We also cover the aspects of ground signal processing and calibration peculiar to the polarimetric signals. The basic theory underlying imaging radar polarimetry for the study of natural surfaces is fairly well developed at this point in time, that is, the fundamental equations are understood in the context of investigation of the Earth's surface. Several instruments are currently in operation with several others being planned, including spaceborne implementations. We discuss several of the currently operating instruments and some of the implementations now planned for future use. Already a wide variety of natural terrains have been mapped using these new instruments. The observed scattering characteristics vary as a function of polarization state and also of frequency. Nature appears to be described by what is now a bewildering variety of polarization signatures. At present we are unable to model accurately all of these types of scattering, but imaging polarimetry is a promising tool to aid in this process and in the understanding of the Earth system. RP ZEBKER, HA (reprint author), CALTECH,JET PROP LAB,RADAR SCI & SYST STUDIES GRP,PASADENA,CA 91109, USA. NR 55 TC 81 Z9 100 U1 2 U2 18 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9219 J9 P IEEE JI Proc. IEEE PD NOV PY 1991 VL 79 IS 11 BP 1583 EP 1606 DI 10.1109/5.118982 PG 24 WC Engineering, Electrical & Electronic SC Engineering GA GV349 UT WOS:A1991GV34900002 ER PT J AU PLATT, SR HILDEBRAND, RH PERNIC, RJ DAVIDSON, JA NOVAK, G AF PLATT, SR HILDEBRAND, RH PERNIC, RJ DAVIDSON, JA NOVAK, G TI 100-MU-M ARRAY POLARIMETRY FROM THE KUIPER-AIRBORNE-OBSERVATORY - INSTRUMENTATION, TECHNIQUES, AND 1ST RESULTS SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE INSTRUMENTATION; POLARIMETRY; FAR-INFRARED ID H2O MASER SOURCES; H-II REGIONS; MAGNETIC-FIELD; ORION NEBULA; SUBMILLIMETER POLARIZATION; MOLECULAR CLOUD; PROPER MOTIONS; W3; DISTANCES; CORE AB The University of Chicago far-infrared array polarimeter, STOKES, is the first multiple-beam polarimeter for far-infrared astronomy. Observations are made from the NASA Kuiper Airborne Observatory. Two orthogonal components of linear polarization are detected simultaneously by corresponding pairs of bolometers in two 32-detector arrays. Removal of the effects induced by the polarimeter and telescope from the measured signals is complicated by the multiple optic axes defined by the 32 independent pixels of the instrument. Novel observing and data-analysis techniques are used to overcome the inherent difficulties of array polarimetry. Results from the first observing flights with the new instrument are reported for the molecular clouds W3 and W51. The measurements show that the magnetic-field structure in both clouds is nonuniform on the scale of 0.5-1.5 pc. This is consistent with molecular line and Zeeman observations that indicate the presence of turbulent velocities and significant small-scale structure. Preliminary results from the second flight series have yielded approximately 40 new measurements in the Sgr A complex. These results indicate that modifications made since the first flights have significantly improved the performance of STOKES. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV MASSACHUSETTS,FIVE COLL RADIO ASTRON OBSERV,AMHERST,MA 01003. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. UNIV CHICAGO,YERKES OBSERV,CHICAGO,IL 60637. RP PLATT, SR (reprint author), UNIV CHICAGO,ENRICO FERMI INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 40 TC 41 Z9 42 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 NOV PY 1991 VL 103 IS 669 BP 1193 EP 1210 DI 10.1086/132940 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR792 UT WOS:A1991GR79200007 ER PT J AU ZILLIAC, GG CLIFFTON, EW AF ZILLIAC, GG CLIFFTON, EW TI WIND-TUNNEL STUDY OF AN OBSERVATORY DOME WITH A CIRCULAR APERTURE SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE WIND TUNNEL; OBSERVATORY; HOT WIRE; SEEING; AERODYNAMICS AB The undesirable effects of wind on the image quality obtained at astronomical facilities can be manifested in several ways. First, the image can vibrate as a result of wind shaking the telescope structure. Second, image spread occurs when the mirror-to-air interface is not in thermal equilibrium. Last, optical wavefront distortions cause image spread at the dome interior-to-exterior air interface as a result of temperature gradients. This report describes results of a wind-tunnel test of a new concept in observatory dome design, the fixed shutter dome, which is intended to protect telescopes from wind shake. The concept is an evolution of the split-sphere topology first seen on the 2-meter telescope at Pic-du-Midi Observatory (France). In order to close larger apertures, the new design allows an upper spherical segment to rotate under a shell of slightly larger diameter which is fixed to a lower rotatable segment. This design is structurally more efficient than conventional designs. From an aerodynamic standpoint, the new dome configuration is similar in overall shape to conventional observatory domes, with the exception of the telescope viewing aperture. The new design consists of a circular aperture of reduced area in contrast to conventional domes with rectangular or slotted openings. Wind-tunnel results of a side-by-side comparison of the new dome with a conventional dome demonstrate that the mean and fluctuating velocity through the aperture and in the center of the new dome configuration are lower than those of conventional domes, thus reducing the likelihood of telescope flow-induced vibration. C1 MONOPTEC CORP,SAN FRANCISCO,CA 94102. RP ZILLIAC, GG (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 4 TC 0 Z9 0 U1 0 U2 1 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 NOV PY 1991 VL 103 IS 669 BP 1211 EP 1217 DI 10.1086/132941 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR792 UT WOS:A1991GR79200008 ER PT J AU KUEHN, CE HIMWICH, WE CLARK, TA MA, C AF KUEHN, CE HIMWICH, WE CLARK, TA MA, C TI AN EVALUATION OF WATER-VAPOR RADIOMETER DATA FOR CALIBRATION OF THE WET PATH DELAY IN VERY LONG BASE-LINE INTERFEROMETRY EXPERIMENTS SO RADIO SCIENCE LA English DT Article ID LENGTH; GEODESY AB The internal consistency of the baseline length measurements derived from analysis of several independent very long baseline interferometry (VLBI) experiments is an estimate of the measurement precision. In this paper we investigate whether the inclusion of water vapor radiometer (WVR) data as an absolute calibration of the propagation delay due to water vapor improves the precision of VLBI baseline length measurements. We analyzed 28 International Radio Interferometric Surveying runs between June 1988 and January 1989; WVR measurements were made at the G. R. Agassiz Station of the Harvard College Observatory in Ft. Davis, Texas, during each session. We found that the addition of WVR data decreased the scatter of the length measurements of Ft. Davis baselines by 5-10%. The observed reduction in the scatter of the baseline lengths is less than what we would expect from the behavior of the formal errors, which suggest that the baseline length measurement precision should improve 10-20% if WVR data at Ft. Davis are included in the analysis. The discrepancy between the formal errors and the baseline length results could be explained as the consequence of systematic errors in the dry-mapping function parameters, instrumental biases in the WVR and Ft. Davis barometer, or both. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP KUEHN, CE (reprint author), INTERFEROMET INC,CODE 9269,GREENBELT,MD 20771, USA. NR 25 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD NOV-DEC PY 1991 VL 26 IS 6 BP 1381 EP 1391 DI 10.1029/91RS02020 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA GZ533 UT WOS:A1991GZ53300002 ER PT J AU RUF, CS AF RUF, CS TI ERROR ANALYSIS OF IMAGE-RECONSTRUCTION BY A SYNTHETIC APERTURE INTERFEROMETRIC RADIOMETER SO RADIO SCIENCE LA English DT Article ID MICROWAVE AB An error analysis is presented for the image reconstruction algorithm currently employed by the electronically steered thinned array radiometer aircraft instrument. This instrument samples components of the Fourier transform of the brightness temperature distribution at 1.4 GHz. Sources of error are identified, including systematic offsets and stochastic noise in the measurements, errors in the interference pattern antenna calibration, multipath scattering from the antenna support structure, mutual coupling between nearby array elements, and variations in the antenna patterns of the array elements. These errors are shown to produce artifacts in the image which appear as "streaks" running along the instrument flight line. Possible hardware corrections are discussed. These include a reduction in the profile of the antenna support structure and a decoupling of adjacent and other nearby array elements using corrugated "skirts." Also discussed are several image enhancement techniques which detect and correct for some of the streaking. These techniques include a renormalization of the interference patterns based on the measured element patterns, a perturbation based interpretation of image contrast, and a covariance analysis of noise present in the image. RP RUF, CS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Ruf, Christopher/I-9463-2012 NR 11 TC 17 Z9 18 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD NOV-DEC PY 1991 VL 26 IS 6 BP 1419 EP 1434 DI 10.1029/91RS02355 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA GZ533 UT WOS:A1991GZ53300006 ER PT J AU ECK, TF DYE, DG AF ECK, TF DYE, DG TI SATELLITE ESTIMATION OF INCIDENT PHOTOSYNTHETICALLY ACTIVE RADIATION USING ULTRAVIOLET REFLECTANCE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SIMPLE PHYSICAL MODEL; SOLAR-RADIATION; SURFACE; CLOUD; IRRADIANCE; INSOLATION; COMPONENTS; BIOSPHERE; VALLEY; EARTH AB A new satellite remote sensing method for estimating the amount of photosynthetically active radiation (PAR, 400-700 nm) incident at the earth's surface is described and tested. Potential incident PAR for clear sky conditions is computed from an existing spectral model. Actual incident PAR is estimated by accounting for the attenuation of PAR due to reflectance by clouds. PAR reflectance from clouds is inferred from ultraviolet (UV) reflectance at 370 nm, based on the evidently constant reflectivity of clouds across UV and PAR wavebands. A major advantage of the UV approach over existing visible band approaches to estimating insolation is the improved ability to discriminate clouds from high-albedo background surfaces. UV spectral reflectance data from the Total Ozone Mapping Spectrometer (TOMS) were used to test the approach for three climatically distinct, midlatitude locations. Estimates of monthly total incident PAR from the satellite technique differed from values computed from ground-based pyranometer measurements by less than 6%. This UV remote sensing method can be applied to estimate PAR insolation over ocean and land surfaces which are free of ice and snow. C1 UNIV MARYLAND,DEPT GEOG,GLOBAL REMOTE SENSING STUDIES LAB,COLLEGE PK,MD 20742. RP ECK, TF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ST SYST CORP,CODE 923,GREENBELT,MD 20771, USA. RI ECK, THOMAS/D-7407-2012 NR 43 TC 65 Z9 72 U1 1 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 NOV PY 1991 VL 38 IS 2 BP 135 EP 146 DI 10.1016/0034-4257(91)90075-H PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA GW027 UT WOS:A1991GW02700003 ER PT J AU SINHA, MP TOMASSIAN, AD AF SINHA, MP TOMASSIAN, AD TI DEVELOPMENT OF A MINIATURIZED, LIGHTWEIGHT MAGNETIC-SECTOR FOR A FIELD-PORTABLE MASS SPECTROGRAPH SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We have designed and fabricated a miniaturized, light-weight magnetic sector for a focal plane mass spectrograph (Mattauch-Herzog design) by using a new high-energy-product magnet material (Nd-B-Fe alloy), and a high permeability magnet yoke material (V-Co-Fe alloy). The magnetic sector weighs less than 10 kg and has a focal plane of 5.1 cm in length and covers a nominal mass range of 40-240 amu. Such a magnetic sector in conjunction with an array detector and a short microbore capillary column is eminently suited for the development of a field-portable gas chromatograph-mass spectrometer instrument of high performance. RP SINHA, MP (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 5 TC 43 Z9 43 U1 1 U2 7 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 NOV PY 1991 VL 62 IS 11 BP 2618 EP 2620 DI 10.1063/1.1142240 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA GN773 UT WOS:A1991GN77300016 ER PT J AU HERRMANN, CC AF HERRMANN, CC TI STICK-SLIPPING SO SCIENCES-NEW YORK LA English DT Letter RP HERRMANN, CC (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0036-861X J9 SCIENCES JI Sci.-New York PD NOV-DEC PY 1991 VL 31 IS 6 BP 56 EP 56 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GL445 UT WOS:A1991GL44500019 ER PT J AU GAYDA, J DRESHFIELD, RL GABB, TP AF GAYDA, J DRESHFIELD, RL GABB, TP TI THE EFFECT OF POROSITY AND GAMMA-GAMMA-' EUTECTIC CONTENT ON THE FATIGUE BEHAVIOR OF HYDROGEN CHARGED PWA-1480 SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article RP GAYDA, J (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 4 TC 6 Z9 7 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 NOV PY 1991 VL 25 IS 11 BP 2589 EP 2594 DI 10.1016/0956-716X(91)90074-B PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GM988 UT WOS:A1991GM98800034 ER PT J AU STAHL, RS JAMES, BR AF STAHL, RS JAMES, BR TI ZINC SORPTION BY B-HORIZON SOILS AS A FUNCTION OF PH SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID HEAVY-METALS; ADSORPTION; SOLUBILITY; OXIDES; MECHANISMS; COPPER; LEAD; IRON; ACID AB Better information is needed to predict how soil acidity affects exchangeability of heavy metals in soils dominated by Fe and Mn oxides with pH-dependent charge. Our laboratory study sought to separate exchangeable and nonexchangeable Zn sorbed by four B horizon soil materials with varied mineralogy and sesquioxide contents. A Myersville silt loam (fine-loamy, mixed, mesic Ultic Hapludalf), a Jackland sandy loam (fine, mixed, mesic Aquic Hapludalf), a Christiana sandy loam (clayey, kaolinitic, mesic Typic Paleudult), and an Evesboro loamy sand (mesic, coated Typic Quartzipsamment) were compared for the exchangeability of Zn as a function of pH. Surface charge was measured across the pH range of 3.5 to 7.6, a 175-mu-mol ZnCl2/kg soil treatment was applied, and sorbed Zn was exchanged with K. Cation-exchange capacity (CEC) was positively correlated with nonexchangeable but not with exchangeable Zn forms. All four soils retained nearly the same amount of Zn, even though CEC ranged from < 10 to > 80 mmol5/kg. An abrupt transition from exchangeable to nonexchangeable Zn occurred in the pH range 5.6 to 5.9 of the Myersville, Evesboro, and Christiana soils. Differences in oxide mineralogy and proton buffering intensity appeared more important than CEC as controls on the exchangeability of Zn in these soils. This result is germane to predicting retention of heavy metals in sewage-sludge-amended agricultural soils. C1 UNIV MARYLAND,DEPT AGRON,COLLEGE PK,MD 20742. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 26 TC 46 Z9 51 U1 2 U2 7 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 NOV-DEC PY 1991 VL 55 IS 6 BP 1592 EP 1597 PG 6 WC Soil Science SC Agriculture GA HB462 UT WOS:A1991HB46200015 ER PT J AU TSUNETA, S ACTON, L BRUNER, M LEMEN, J BROWN, W CARAVALHO, R CATURA, R FREELAND, S JURCEVICH, B MORRISON, M OGAWARA, Y HIRAYAMA, T OWENS, J AF TSUNETA, S ACTON, L BRUNER, M LEMEN, J BROWN, W CARAVALHO, R CATURA, R FREELAND, S JURCEVICH, B MORRISON, M OGAWARA, Y HIRAYAMA, T OWENS, J TI THE SOFT-X-RAY TELESCOPE FOR THE SOLAR-A MISSION SO SOLAR PHYSICS LA English DT Article ID I TELESCOPE; ABERRATION AB The Soft X-ray Telescope (SXT) of the SOLAR-A mission is designed to produce X-ray movies of flares with excellent angular and time resolution as well as full-disk X-ray images for general studies. A selection of thin metal filters provide a measure of temperature discrimination and aid in obtaining the wide dynamic range required for solar observing. The co-aligned SXT aspect telescope will yield optical images for aspect reference, white-light flare and sunspot studies, and, possibly, helioseismology. This paper describes the capabilities and characteristics of the SXT for scientific observing. C1 LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. INST SPACE & ASTRON SCI,SAGAMIHARA,JAPAN. NATL ASTRON OBSERV JAPAN,MITAKA,TOKYO 181,JAPAN. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP TSUNETA, S (reprint author), UNIV TOKYO,INST ASTRON,MITAKA,TOKYO 181,JAPAN. NR 23 TC 966 Z9 978 U1 1 U2 14 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 NOV PY 1991 VL 136 IS 1 BP 37 EP 67 DI 10.1007/BF00151694 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GU809 UT WOS:A1991GU80900004 ER PT J AU HENDERSON, GN GAYLORD, TK GLYTSIS, EN FIRST, PN KAISER, WJ AF HENDERSON, GN GAYLORD, TK GLYTSIS, EN FIRST, PN KAISER, WJ TI BALLISTIC ELECTRON-EMISSION TESTING OF SEMICONDUCTOR HETEROSTRUCTURES SO SOLID STATE COMMUNICATIONS LA English DT Article ID CURRENT-VOLTAGE CHARACTERISTICS; QUANTUM-WELL; ROOM-TEMPERATURE; SUPERLATTICE; STATES; SPECTROSCOPY; MICROSCOPY AB In ballistic electron emission microscopy (BEEM) and spectroscopy, ballistic electrons are injected into a sample using a scanning tunneling microscope to probe the electrical properties of buried interfaces. In this communication, a method is proposed that uses the BEEM technique to observe the electron wave optical properties of semiconductor heterostructures. This method provides a three-terminal configuration for characterizing electron wave devices that overcomes many of the limitations encountered in other two- and three-terminal measurement techniques. Specifically, the method provides an injector, which is well isolated from the heterostructure, that injects a collimated beam of ballistic carriers with a precisely controlled energy distribution. These carriers accurately probe the quantum transmittance of a voltage-tunable electron wave interference structure, which can be designed with a light doping to minimize impurity and electron-electron scattering. A general procedure is presented for analyzing this experimental configuration based on a combination of the models used to describe BEEM and ballistic electron transport in semiconductors. Using this procedure, BEEM testing of an electron wave energy filter is modeled and clear quantum interference effects are predicted. This BEEM configuration should allow for the precise characterization of a wide range of ballistic electron transport effects such as quantum reflections from interfaces and electron wave interference effects, phenomena that are presently of wide interest. C1 GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP HENDERSON, GN (reprint author), GEORGIA INST TECHNOL,SCH ELECT ENGN,MICROELECTR RES CTR,ATLANTA,GA 30332, USA. RI Glytsis, Elias/M-5066-2013 NR 26 TC 23 Z9 23 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD NOV PY 1991 VL 80 IS 8 BP 591 EP 596 DI 10.1016/0038-1098(91)90158-R PG 6 WC Physics, Condensed Matter SC Physics GA GU852 UT WOS:A1991GU85200012 ER PT J AU JONES, FC ELLISON, DC AF JONES, FC ELLISON, DC TI THE PLASMA PHYSICS OF SHOCK ACCELERATION SO SPACE SCIENCE REVIEWS LA English DT Review ID EARTHS BOW SHOCK; QUASI-PARALLEL SHOCKS; COSMIC-RAY ACCELERATION; ACTIVE GALACTIC NUCLEI; ADIABATIC ENERGY CHANGE; ALIGNED BEAMS UPSTREAM; INTERPLANETARY TRAVELING SHOCKS; HYDROMAGNETIC WAVE EXCITATION; NONCOPLANAR MAGNETIC-FIELDS; MONTE-CARLO SIMULATION AB The notion that plasma shocks in astrophysical settings can and do accelerate charged particles to high energies is not a new one. However, in recent years considerable progress has been achieved in understanding the role particle acceleration plays both in astrophysics and in the shock process itself. In this paper we briefly review the history and theory of shock acceleration, paying particular attention to theories of parallel shocks which include the backreaction of accelerated particles on the shock structure. We discuss in detail the work that computer simulations, both plasma and Monte Carlo, are playing in revealing how thermal ions interact with shocks and how particle acceleration appears to be an inevitable and necessary part of the basic plasma physics that governs collisionless shocks. We briefly describe some of the outstanding problems that still confront theorists and observers in this field. C1 N CAROLINA STATE UNIV,DEPT PHYS,RALEIGH,NC 27695. RP JONES, FC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 230 TC 593 Z9 596 U1 4 U2 29 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD NOV PY 1991 VL 58 IS 3-4 BP 259 EP 346 DI 10.1007/BF01206003 PG 88 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GR363 UT WOS:A1991GR36300002 ER PT J AU SODUPE, M BAUSCHLICHER, CW AF SODUPE, M BAUSCHLICHER, CW TI THEORETICAL-STUDY OF THE BONDING OF THE 1ST-ROW AND 2ND-ROW TRANSITION-METAL POSITIVE-IONS TO ACETYLENE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; 2 WATER-MOLECULES; GAS-PHASE; BINDING-ENERGIES; PERIODIC TRENDS; SCANDIUM IONS; GROUND-STATE; ORBITALS; ATOMS; THERMOCHEMISTRY AB The bonding of transition-metal ions to acetylene is studied by using a theoretical treatment that includes electron correlation. The ions on the left side of the first and second transition rows insert into the pi-bond to form a three-membered ring. On the right side of the row the bonding is electrostatic. The trends in bonding are discussed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 38 TC 93 Z9 93 U1 0 U2 6 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 OCT 31 PY 1991 VL 95 IS 22 BP 8640 EP 8645 DI 10.1021/j100175a042 PG 6 WC Chemistry, Physical SC Chemistry GA GX469 UT WOS:A1991GX46900042 ER PT J AU CARDELINO, BH MOORE, CE STICKEL, RE AF CARDELINO, BH MOORE, CE STICKEL, RE TI STATIC 2ND-ORDER POLARIZABILITY CALCULATIONS FOR LARGE MOLECULAR-SYSTEMS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SUBSTITUTED CONJUGATED MOLECULES; 2ND ORDER HYPERPOLARIZABILITY; NONLINEAR SUSCEPTIBILITIES; OPTICAL SUSCEPTIBILITY; PARA-NITROANILINE; ORGANIC-SYSTEMS; DIPOLE-MOMENT; CHARGE; DISPERSION; BENZENE AB A procedure to calculate all second-order polarizability tensor elements in static fields has been developed. The calculations are based on semiempirical Hamiltonians (MNDO) that include shaped electric fields. The technique has been applied to mono-, di-, and trisubstituted benzenes incorporating nitro, methyl, and primary and secondary amino groups. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP CARDELINO, BH (reprint author), ATLANTA UNIV CTR,SPELMAN COLL,DOLPHUS E MILLIGAN SCI RES INST,ATLANTA,GA 30310, USA. NR 40 TC 34 Z9 34 U1 0 U2 0 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 OCT 31 PY 1991 VL 95 IS 22 BP 8645 EP 8652 DI 10.1021/j100175a043 PG 8 WC Chemistry, Physical SC Chemistry GA GX469 UT WOS:A1991GX46900043 ER PT J AU WEISSMAN, P AF WEISSMAN, P TI SOLAR-SYSTEM - WHY DID HALLEY HICCUP SO NATURE LA English DT Editorial Material ID COMETARY NUCLEI; EVOLUTION; CHIRON RP WEISSMAN, P (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 15 TC 12 Z9 12 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD OCT 31 PY 1991 VL 353 IS 6347 BP 793 EP 794 DI 10.1038/353793a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GM732 UT WOS:A1991GM73200031 ER PT J AU HALZEN, F ZAS, E MACGIBBON, JH WEEKES, TC AF HALZEN, F ZAS, E MACGIBBON, JH WEEKES, TC TI GAMMA-RAYS AND ENERGETIC PARTICLES FROM PRIMORDIAL BLACK-HOLES SO NATURE LA English DT Review ID ASTRONOMICAL OBJECTS; NONROTATING HOLE; COSMIC STRINGS; EMISSION RATES; EARLY UNIVERSE; BURSTS; EXPLOSIONS; SEARCH; RADIATION; SPECTRUM AB Black holes of almost arbitrarily small mass may have formed in the very early Universe. Their presence today would be revealed by the energetic radiation they would produce by means of the quantum-gravitational Hawking mechanism, allowing observational limits to be set on their density today and on their past significance. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. HARVARD SMITHSONIAN CTR ASTROPHYS,WHIPPLE OBSERV,AMADO,AZ 85645. RP HALZEN, F (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. RI zas, enrique/I-5556-2015 OI zas, enrique/0000-0002-4430-8117 NR 54 TC 97 Z9 100 U1 0 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD OCT 31 PY 1991 VL 353 IS 6347 BP 807 EP 815 DI 10.1038/353807a0 PG 9 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GM732 UT WOS:A1991GM73200049 ER PT J AU STONE, EC MINER, ED AF STONE, EC MINER, ED TI THE VOYAGER ENCOUNTER WITH NEPTUNE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article RP STONE, EC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 18903 EP 18906 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200001 ER PT J AU CONRATH, BJ GAUTIER, D LINDAL, GF SAMUELSON, RE SHAFFER, WA AF CONRATH, BJ GAUTIER, D LINDAL, GF SAMUELSON, RE SHAFFER, WA TI THE HELIUM ABUNDANCE OF NEPTUNE FROM VOYAGER MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID RADIO OCCULTATION MEASUREMENTS; OUTER SOLAR-SYSTEM; GIANT PLANETS; PARA-HYDROGEN; MONODEUTERATED METHANE; DEEP ATMOSPHERE; D/H RATIO; ELEMENTS; URANUS; SPECTRUM AB Voyager radio occultation and infrared spectrometer measurements are used to obtain an estimate of the helium abundance in the atmosphere of Neptune. It is found that the shape of the measured spectrum cannot be well matched by spectra calculated from atmospheric models that include only gaseous opacity. The most plausible explanation of the observed spectral shape appears to require the existence of an additional opacity source associated with clouds or hazes. The data can be fit with either a tropospheric or a stratospheric cloud model. If a tropospheric cloud is invoked, an optical thickness at 200 cm-1 between 1 and 8 is required, depending on the particle size assumed. For a stratospheric cloud an optical thickness between 0.2 and 0.8 is required. Optical constants for methane ice are used, but ethane has similar optical properties in this spectral region. Assuming no modification to the temperature profile is required other than a molecular weight adjustment, a combination of gas and cloud opacities produces a good fit to the spectrum for a helium mole fraction q(He) = 0.190 +/- 0.032, corresponding to a mass fraction Y = 0.32 +/- 0.05. Within the measurement uncertainties the Neptune helium abundance may be compatible with that of Uranus and, marginally, with the protosolar value. However, models in which the outer part of the primitive solar nebular was enriched in CO and N2, leading to an enhanced atmospheric He/H-2 ratio, cannot be ruled out at this time. C1 OBSERV PARIS,SECT MEUDON,DEPT RECH SPATIALE,F-92195 MEUDON,FRANCE. CALTECH,JET PROP LAB,PASADENA,CA 91109. USN,RES LAB,WASHINGTON,DC 20375. RP CONRATH, BJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 693-2,GREENBELT,MD 20771, USA. NR 59 TC 56 Z9 56 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 OCT 30 PY 1991 VL 96 SU S BP 18907 EP 18919 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200002 ER PT J AU PEARL, JC CONRATH, BJ AF PEARL, JC CONRATH, BJ TI THE ALBEDO, EFFECTIVE TEMPERATURE, AND ENERGY-BALANCE OF NEPTUNE, AS DETERMINED FROM VOYAGER DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED OBSERVATIONS; HELIUM ABUNDANCE; BOLOMETRIC ALBEDOS; INTERNAL HEAT; URANUS; ABSORPTION; JUPITER; SATURN; PLANETS; SYSTEM AB Data from the Voyager infrared spectrometer and radiometer (IRIS) investigation are used in determining the albedo, effective temperature, and energy balance of Neptune. From broadband radiometric observations made at phase angles of 14-degrees and 134-degrees, together with measurements at intermediate phase angles from the literature, an orbital mean value for the bolometric Bond albedo, ABAR = 0.290 +/- 0.067, is obtained; this yields an equilibrium temperature T(eq) = 46.6 +/- 1.1 K. From thermal spectra obtained over latitudes from pole to pole an effective temperature T(eff) = 59.3 +/- 0.8 K is derived. This represents a substantial improvement over previously determined values. The energy balance of Neptune is therefore E = 2.61 +/- 0.28, which is in agreement with previous results. The reduced uncertainty in this value is due to the improved determination of the effective temperature. C1 NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 693-2,GREENBELT,MD 20771. NR 35 TC 67 Z9 67 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 18921 EP 18930 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200003 ER PT J AU CONRATH, BJ FLASAR, FM GIERASCH, PJ AF CONRATH, BJ FLASAR, FM GIERASCH, PJ TI THERMAL STRUCTURE AND DYNAMICS OF NEPTUNE ATMOSPHERE FROM VOYAGER MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED OBSERVATIONS; SPACED DATA; JUPITER; URANUS; SYSTEM AB Spatially resolved Voyager infrared spectra from a global mapping sequence are used to characterize the thermal structure of the atmosphere of Neptune between approximately 50 and 100 mbar. A zonal mean meridional temperature cross section is obtained, which shows a minimum in the upper tropospheric and lower stratospheric temperatures at southern mid latitudes with maxima at the equator and high southern latitudes. This is qualitatively similar to the structure observed on Uranus, even though the obliquities and internal heat fluxes of the two planets are quite different. Thermal wind calculations show zonal wind speeds decreasing with altitude at all latitudes. Within the framework of a linear radiative-dynamical model, the thermal structure and cloud top winds together imply a frictional damping time comparable in magnitude to the radiative relaxation time; similar results have previously been obtained for the other three giant planets. Periodogram techniques for used to search the observed longitude variations of temperature for possible planetary-scale wave features. Data from two latitude bins are analyzed; one of the bins includes the Great Dark Spot, and the other is centered on the southern mid-latitude minimum in the zonal mean temperature. A weakly significant feature near planetary wavenumber 4 is identified at the latitude of the spot. The rest of the variance can be attributed to instrument noise and possibly a broadband meteorological spectrum indistinguishable from white noise. C1 CORNELL UNIV,CTR RADIOPHYS & SPACE RES,ITHACA,NY 14853. RP CONRATH, BJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693-2,GREENBELT,MD 20771, USA. RI Flasar, F Michael/C-8509-2012 NR 18 TC 35 Z9 35 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 18931 EP 18939 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200004 ER PT J AU BEZARD, B ROMANI, PN CONRATH, BJ MAGUIRE, WC AF BEZARD, B ROMANI, PN CONRATH, BJ MAGUIRE, WC TI HYDROCARBONS IN NEPTUNE STRATOSPHERE FROM VOYAGER INFRARED OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID URANUS; SPECTRA; ETHANE; OCCULTATION; ATMOSPHERE; TEMPERATURE; ABSORPTION; METHANE; TRITON; SYSTEM AB Emission from the acetylene and ethane bands at 729 and 822 cm-1 detected in the Voyager infrared spectra of Neptune has been analyzed. A large selection of low-spatial resolution spectra was used to derive the disk-averaged abundances of C2H2 and C2H6. Under the assumption of uniform vertical distributions above the saturation region, a C2H2 mixing ratio of 6(-4)+14 X 10(-8) and a C2H6 mixing ratio of 1.5(-0.5)+2.5 x 10(-6) were inferred. The accuracy of the retrievals is limited by the large uncertainty in the stratospheric temperature structure. The maximum contribution to the observed C2H2 and C2H6 emission comes from the 0.2- and 0.7-mbar regions, respectively. Mixing ratio profiles derived from photochemical modeling, which are not constant with height above the saturation region, indicate that the hydrocarbon emission is most sensitive to the assumed eddy diffusion coefficient in the millibar region. Either the C2H2 or the C2H6 emission can be reproduced by the photochemical model to within the accuracy of the retrievals, but not both simultaneously. Best fits to both emission features simultaneously occur with C2H2 mixing ratios a factor of 2 too high and C2H6 mixing ratios a factor of 2 too low. We consider this agreement satisfactory considering the unknowns in the chemical and photolytic processes. A set of Voyager spectra at higher spatial resolution was used to study the latitudinal variation of the C2H2 emission between 30-degrees-N and 80-degrees-S. Zonal mean radiances at the C2H2 peak show a minimum near 50-degrees-S-60-degrees-S and maxima near the south pole and equator. This behavior is similar to that observed at 350 and 250 cm-1, where the lower stratosphere and troposphere are sounded. The mid-latitude minimum can be explained by a fivefold depletion of acetylene or a temperature decrease of about 15 K (or any combination of the two effects) in the 0.03- to 2-mbar region. The latitude variation in the C2H2 emission could result from a circulation pattern forced from deep levels, with upwelling at mid-latitudes and subsidence at low and high latitudes. C1 SCI SYST & APPLICAT INC,LANHAM,MD 20706. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BEZARD, B (reprint author), OBSERV PARIS,SECT MEUDON,DEPT RECH SPATIALE,F-92195 MEUDON,FRANCE. RI Romani, Paul/D-2729-2012 NR 38 TC 48 Z9 48 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 18961 EP 18975 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200006 ER PT J AU CONNERNEY, JEP ACUNA, MH NESS, NF AF CONNERNEY, JEP ACUNA, MH NESS, NF TI THE MAGNETIC-FIELD OF NEPTUNE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ZONAL HARMONIC MODEL; GEOMAGNETIC-FIELD; PLASMA OBSERVATIONS; HOT PLASMA; URANUS; VOYAGER-2; MAGNETOSPHERE; INTERIOR; SPECTRUM; PRESSURE AB A spherical harmonic model of the planetary magnetic field of Neptune is obtained from the Voyager 2 encounter observations. The model is obtained by partial solution to the underdetermined inverse problem (eighth-order and degree spherical harmonic model) using generalized inverse techniques. Dipole and quadrupole Schmidt-normalized spherical harmonic coefficients are determined, or resolved, independently of higher-order terms. Much additional information is also obtained regarding octupole and higher-order components of the field. Model parameter resolution and uniqueness are addressed using new visual representations of the "resolution matrix." The model yields a dipole of magnitude 0. 14 G R(N)3, tilted by 47-degrees toward 72-degrees-west longitude. Neptune's quadrupole is relatively large, equal to or exceeding in magnitude the (surface) dipole field. The octupole is likewise very large but less well constrained. The magnetic fields of Neptune and Uranus are very much alike and equally unlike those of the other known magnetized planets. Characteristics of this complex magnetic field are illustrated, using contour maps of the field on the planet's surface, and discussed in the context of dynamo generation in the relatively poorly conducting "ice mantle." C1 UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP CONNERNEY, JEP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI connerney, john/I-5127-2013; OI connerney, jack/0000-0001-7478-6462 NR 50 TC 77 Z9 77 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-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19023 EP 19042 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200010 ER PT J AU KAISER, ML ZARKA, P DESCH, MD FARRELL, WM AF KAISER, ML ZARKA, P DESCH, MD FARRELL, WM TI RESTRICTIONS ON THE CHARACTERISTICS OF NEPTUNIAN LIGHTNING SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID RADIO; WHISTLERS; VOYAGER-2 AB Although lightning-triggered whistlers were detected by the Voyager 2 plasma wave experiment at Neptune, only four possible lightning sferics were detected by the planetary radio astronomy instrument. This low level of detection places strict limits on the characteristics of Neptunian lightning, ruling out lightning with power levels as high as those observed at Saturn or Uranus, but leaving the intriguing possibility that lightning slightly stronger than normal terrestrial lightning flashes but with much lower occurrence rate could exist. Possible scenarios to explain the observations are examined, including reduced NH3 concentration in the planet's atmosphere and an unusually slow risetime discharge process. C1 OBSERV PARIS,DASOP,F-92195 MEUDON,FRANCE. RP KAISER, ML (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 22 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19043 EP 19047 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200011 ER PT J AU FARRELL, WM DESCH, MD KAISER, ML CALVERT, W AF FARRELL, WM DESCH, MD KAISER, ML CALVERT, W TI EVIDENCE OF AURORAL PLASMA CAVITIES AT URANUS AND NEPTUNE FROM RADIO-BURST OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID KILOMETRIC RADIATION; MAGNETIC-FIELDS; EMISSIONS; VOYAGER-2; GROWTH AB Radio bursts originating from the stronger magnetic polar regions of both Uranus and Neptune were detected by the planetary radio astronomy experiment during the Voyager 2 encounters with the planets. It has previously been demonstrated that these bursts are beamed into a broad, hollow emission pattern from their auroral sources. We now show that the bursts at both planets also manifest similar detailed patterns, with the waves beamed into two separate and distinct radiation cones at intermediate wave frequencies. This double-cone emission pattern is predicted by relativistic cyclotron resonance theory, and application of this theory to the observed emission pattern yields the plasma density structure within the radio source region. Calculations indicate that at both Uranus and Neptune the plasma-to-cyclotron frequency ratio can drop well below 0.01 within the active region. Such low values indicate that the southern auroral zones at both planets contain an auroral plasma cavity that is similar to that found in Earth's nightside auroral zone. C1 UNIV IOWA HOSP & CLIN,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. RP FARRELL, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 29 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-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19049 EP 19059 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200012 ER PT J AU MAUK, BH KEATH, EP KANE, M KRIMIGIS, SM CHENG, AF ACUNA, MH ARMSTRONG, TP NESS, NF AF MAUK, BH KEATH, EP KANE, M KRIMIGIS, SM CHENG, AF ACUNA, MH ARMSTRONG, TP NESS, NF TI THE MAGNETOSPHERE OF NEPTUNE - HOT PLASMAS AND ENERGETIC PARTICLES SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID VOYAGER SPACECRAFT; SATURNIAN MAGNETOSPHERE; JOVIAN MAGNETOSPHERE; TRITON TORUS; URANUS; AURORA; ION; DISTRIBUTIONS; MAGNETOTAIL; PULSATIONS AB A comprehensive overview is provided of the hot plasmas and energetic particles (greater-than-or-similar-to 20 ke V) observed in the vicinity of Neptune by the low energy charged particle (LECP) experiment on the Voyager 2 spacecraft. The LECP data are ordered with respect to magnetic field data and models derived from the Voyager magnetometer experiment. The findings include the following: (1) Weakly enhanced ion and electron fluxes were observed at the position of the subsolar bow shock. (2) Magnetic-field-aligned, antiplanetward streaming ions and electrons were sporadically observed within the inbound (subsolar) and outbound (tail flank) magnetosheaths, and within the unique "pole-on" cusp region encountered during the inbound trajectory. (3) Tangential ion streaming was observed at the positions of both the inbound (dawnward streaming) and outbound (tailward streaming) magnetopauses. (4) A distinct "trans-Triton" ion population outside the minimum L shell of Triton is characterized by large angular anisotropies that show that heavy ions (presumably N+) are a likely constituent. This population is at least partially corotating with Neptune out to at least L = 27 R(N) and is also characterized at times by cigar-shaped (field-aligned) pitch angle distributions, possibly indicative of an interaction with a neutral torus. (5) Within the middle magnetospheric regions (inside Triton), pitch angle distributions have well-developed trapped or "pancake" shapes. Also, in contrast to Uranus, flux profiles show no evidence of substorm-generated azimuthal asymmetries. (6) Triton (and/or Triton-generated neutral gas) controls the outer bounds of the hot plasmas and energetic particle although the mechanism of that control is unclear. Also, there are clear charged particle signatures of satellite 1989N1 and of ring 1989N3R. However, the large number of calculated critical L shell positions associated with all of the rings and satellites renders impractical at this time the unique determination of causal relationships between the many observed particle signatures and known material bodies. (7) Concerning the bulk (integral) and spectral parameters of the hot plasmas, if it is assumed that the trans-Triton population is dominated by N+, the plasma beta-parameter reaches approximately 1 within the near-planet magnetotail (L approximately 28 R(N); in conjunction with a magnetic field depression "tail event"), having only reached approximately 0.2 in the more planetward regions. Integral electron energy intensities are such that the more localized Neptune UV aurora can be explained if loss cone intensities are less-than-or-similar-to 1% of trapped intensities. In contrast to the Uranian magnetosphere, the lower-energy electron distributions appear generally to be at least as well characterized by hot Maxwellian distributions (kT = 10 to 30 ke V) as by power law distributions inside L approximately 20 R(N), a characteristic generally exhibited at the other planets by the ions. At Neptune the ions have kT = 12 to 100 keV, and kT is strongly correlated with position relative to Triton's L shell (8) Within the Neptunian magnetotail planetward, magnetic-field-aligned streaming of ions and electrons is observed within the distant (approximately 67 R(N) plasma sheet and within a closer region thought to be a detached or striated portion of the plasma sheet population. Within the near-planet magnetotail (L approximately 28 R(N), where the spacecraft crossed from the plasma sheet to the tail lobes, cigarlike electron distributions are observed, suggestive of shell-splitting/magnetopause-sweeping effects. Consistent with the middle magnetospheric observations, and in sharp contrast to the Uranian magnetotail, the Neptunian magnetotail shows no evidence of substorm processes. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV KANSAS,DEPT PHYS,LAWRENCE,KS 66044. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP MAUK, BH (reprint author), JOHNS HOPKINS UNIV,APPL PHYS LAB,JOHNS HOPKINS RD,LAUREL,MD 20723, USA. RI Mauk, Barry/E-8420-2017 OI Mauk, Barry/0000-0001-9789-3797 NR 58 TC 31 Z9 31 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-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19061 EP 19084 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200013 ER PT J AU ZHANG, M RICHARDSON, JD SITTLER, EC AF ZHANG, M RICHARDSON, JD SITTLER, EC TI VOYAGER-2 ELECTRON OBSERVATIONS IN THE MAGNETOSPHERE OF NEPTUNE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PLASMA OBSERVATIONS; TRITON TORUS; SATURN; SATELLITES; MODEL; ABSORPTION; URANUS; RINGS AB This paper describes electron data obtained during the Neptune encounter by the Voyager 2 plasma science experiment. We derive the densities and temperatures of low-energy (10-5950 eV) electrons and the electrostatic potential of the spacecraft near Neptune. The data indicate that the escape of charged particles from Triton and the local ionization of atoms in the neutral torus originating from Triton are the major plasma sources. We infer that this neutral torus of hydrogen atoms has a density of about 300 cm-3 and an inner boundary at 8 R(N). The data near Neptune exhibit signatures suggesting that both precipitation into Neptune's atmosphere and ring absorption are important plasma loss mechanisms. Plasma transport in the magnetosphere appears to be very fast; the diffusion coefficient is 1 x 10(-7)L3 R(N)2 s-1. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. NR 40 TC 20 Z9 20 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 OCT 30 PY 1991 VL 96 SU S BP 19085 EP 19100 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200014 ER PT J AU DESCH, MD FARRELL, WM KAISER, ML LEPPING, RP STEINBERG, JT VILLANUEVA, LA AF DESCH, MD FARRELL, WM KAISER, ML LEPPING, RP STEINBERG, JT VILLANUEVA, LA TI THE ROLE OF SOLAR-WIND RECONNECTION IN DRIVING THE NEPTUNE RADIO-EMISSION SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SATURNS KILOMETRIC RADIATION; MAGNETOSPHERE; ASTRONOMY; FIELD AB The only remote diagnostic of conditions within the outer planets' magnetospheres is the highly variable flux of low-frequency radio waves. As at the other radio planets, Neptune radio emission also manifests, on a time scale of days, major intensity fluctuations that are indicative of a solar wind energy-coupling process of some kind. We find that the merging of interplanetary magnetic field lines with Neptune's magnetosphere is the best predictor of emitted radio energy. By contrast, viscouslike energy coupling processes, such as might be caused by solar wind density or bulk speed fluctuations, are apparently ineffective in driving the radio emission. C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. RP DESCH, MD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 20 TC 5 Z9 5 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19111 EP 19116 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200016 ER PT J AU SZABO, A SISCOE, GL LAZARUS, AJ MCNUTT, RL LEPPING, RP NESS, NF AF SZABO, A SISCOE, GL LAZARUS, AJ MCNUTT, RL LEPPING, RP NESS, NF TI MAGNETOPAUSE AND CUSP OBSERVATIONS AT NEPTUNE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PLASMA; FIELD AB The fortuitous timing of the Voyager 2 flyby of Neptune provided a unique opportunity to carry out plasma and magnetic field measurements in a subsolar cusp region of a planet. The measured plasma parameters near the inbound magnetopause strongly suggest that a rotational discontinuity separates the magnetosheath and the high-altitude cusp region. After crossing the magnetopause, a thick layer of magnetosheathlike plasma was observed which can be accounted for by two models: (1) either a cusplike layer of stagnant plasma separated from the magnetosheath by a tangential discontinuity, or (2) or a mantlelike layer of dynamic plasma separated from the sheath by a rotational discontinuity. The plasma observations are more consistent with the mantle interpretation. Distinguishing the mantle and the stagnant cusp models is not possible on geometrical grounds because Voyager 2 crossed the magnetic polar region on the subsolar side. Inside the cusp region, there is an overall decrease in the ion density and a concurrent increase in the magnetic field strength which is consistent with a slow mode expansion fan such as is encountered in Earth's polar regions. C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP SZABO, A (reprint author), MIT,CTR SPACE RES,CAMBRIDGE,MA 02139, USA. RI McNutt, Ralph/E-8006-2010 OI McNutt, Ralph/0000-0002-4722-9166 NR 11 TC 14 Z9 14 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 OCT 30 PY 1991 VL 96 SU S BP 19149 EP 19152 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200021 ER PT J AU GURNETT, DA KURTH, WS GRANROTH, LJ ALLENDORF, SC POYNTER, RL AF GURNETT, DA KURTH, WS GRANROTH, LJ ALLENDORF, SC POYNTER, RL TI MICRON-SIZED PARTICLES DETECTED NEAR NEPTUNE BY THE VOYAGER-2 PLASMA-WAVE INSTRUMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PLANETARY RADIO ASTRONOMY; JUPITERS MAGNETOSPHERE; PHYSICAL PROCESSES; MAGNETIC-FIELDS; CHARGED DUST; RING PLANE; URANUS; IMPACTS; SATURN; ORIGIN AB During the Voyager 2 flyby of Neptune the plasma wave and radio astronomy instruments detected numerous impulsive signals that were interpreted as micron-sized particles striking the spacecraft. This paper presents an analysis of the particle impacts observed by the plasma wave instrument. From analysis of wideband antenna voltage waveforms a peak impact rate of 443 s-1 was observed near the inbound equator crossing, which occurred at a radial distance of 3.45 R(N), and a peak impact rate of 151 s-1 was observed near the outbound ring plane crossing, which occurred at a radial distance of 4.20 R(N). The inbound peak is offset by 146 +/- 4 km north of the equatorial plane, and the outbound peak is offset by 948 +/- 65 km south of the equatorial plane. A Gaussian fit of the impact rate profile has a width (to the e-1 points) of 537 +/- 22 km for the inbound "core" component and 2,073 +/- 392 km for the outbound component. These impact rates correspond to maximum number densities of a few times 10(-3) m-3. Analysis of the voltage amplitudes induced on the antenna indicates that the particles have masses ranging from 10(-10) g to a few times 10(-9) g, with an uncertainty of up to a factor of 10. Assuming a mass density of 1 g/cm3, these particles would have radii in the range 5-10-mu-m, with an uncertainty of about a factor of 2 to 3. In addition to the high impact rates observed near the two equator crossings, an impact rate of at least 0.6 s-1 was observed over the entire region inside about 8 R(N), including the northern polar region. Likely sources for these particles include (1) several of the small satellites (1989N1, 1989N2, 1989N3, and 1989N4) discovered near Neptune by Voyager and (2) the rings. Electromagnetic forces may play an important role in diffusing the particles away from the equatorial plane. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP GURNETT, DA (reprint author), UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242, USA. NR 24 TC 32 Z9 32 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-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19177 EP 19186 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200024 ER PT J AU BURATTI, BJ LANE, AL GIBSON, J BURROWS, H NELSON, RM BLISS, D SMYTHE, W GARKANIAN, V WALLIS, B AF BURATTI, BJ LANE, AL GIBSON, J BURROWS, H NELSON, RM BLISS, D SMYTHE, W GARKANIAN, V WALLIS, B TI TRITONS SURFACE-PROPERTIES - A PRELIMINARY-ANALYSIS FROM GROUND-BASED, VOYAGER PHOTOPOLARIMETER SUBSYSTEM, AND LABORATORY MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; DISK-INTEGRATED PHOTOMETRY; RADIATIVE-TRANSFER; ICY SATELLITES; NEPTUNE AB The surface properties of Triton have been determined from a threefold approach involving analysis of ground-based and Voyager photopolarimeter subsystem observations of its phase curve, theoretical modeling, and laboratory measurements of the phase functions of a wide variety of materials. The physical parameters derived include the single-scattering albedo, the single-particle phase function, the compaction state of the optically active portion of the regolith, and the degree of macroscopic roughness. We find that Triton has a high single-scattering albedo (0.96 +/- 0.01 at 0.75-mu-m) and an unusually compacted surface possibly similar to that of Europa. Preliminary results suggest that Triton's single-particle phase function and the macroscopically rough character of its surface are similar to those of most other icy satellites. Laboratory measurements of the phase curve of a sample of a high-albedo, compact volatile-contaminant analogue are in reasonable agreement with Triton's phase curve and provide evidence that the model parameters derived for Triton's surface are physically realistic. RP BURATTI, BJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 37 TC 6 Z9 6 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-PLANET JI J. Geophys. Res.-Planets PD OCT 30 PY 1991 VL 96 SU S BP 19197 EP 19202 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ712 UT WOS:A1991GQ71200026 ER PT J AU GIRDLER, RW AF GIRDLER, RW TI THE AFRO-ARABIAN RIFT SYSTEM - AN OVERVIEW SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT SYMP ON WORLD RIFT SYSTEMS CY APR 27-28, 1989 CL TEXAS A&M UNIV, COLLEGE STN, TX SP NASA, INTER UNION COMMISS LITHOSPHERE HO TEXAS A&M UNIV ID NORTHERN RED-SEA; SAUDI-ARABIA; OCEANIC LITHOSPHERE; CONTINENTAL-MARGIN; PLATE TECTONICS; EVOLUTION; GULF; ADEN; CRUSTAL; AFRICA AB The Afro-Arabian rift system is reviewed beginning with the Dead Sea transform and Gulf of Suez in the north, followed by the Gulf of Aden and Red Sea and ending with a brief mention of rifting through eastern and southern Africa. A consistent interpretation is obtained for geophysical data from the Gulf of Aden and Red Sea and geological data for the Dead Sea transform, Suez graben and Red Sea and Gulf of Aden margins. Geophysical data are used to estimate the locations of the ocean-continent boundaries in the northern Red Sea; these are found to coincide when the total 107 km shear along the Dead Sea is restored. The Red Sea is therefore reconstructed in stages beginning with the 45 km post-Miocene shear and 62 km early-Miocene shear along the Dead Sea transform followed by estimates for extension in the early Red Sea-Suez graben. When this is done, there is a remarkable alignment of various features revealed on Landsat TM imagery for both sides of the northern Red Sea. North-south differences in the Red Sea and west-east differences in the Gulf of Aden are discussed and found to be best explained by a propagating rift model. C1 UNIV NEWCASTLE UPON TYNE,DEPT PHYS,NEWCASTLE TYNE NE1 7RU,TYNE & WEAR,ENGLAND. RP GIRDLER, RW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 920,GREENBELT,MD 20771, USA. NR 45 TC 49 Z9 52 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD OCT 30 PY 1991 VL 197 IS 2-4 BP 139 EP 153 DI 10.1016/0040-1951(91)90038-T PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ737 UT WOS:A1991GQ73700005 ER PT J AU ROBIN, T MESARWI, A WU, NJ FAN, WC ESPOIR, L SEGA, R IGNATIEV, A AF ROBIN, T MESARWI, A WU, NJ FAN, WC ESPOIR, L SEGA, R IGNATIEV, A TI Y1BA2CU3O6+DELTA GROWTH ON THIN Y-ENHANCED SIO2 BUFFER LAYERS ON SILICON SO APPLIED PHYSICS LETTERS LA English DT Article ID BA-CU-O; SI(100) SURFACE; FILMS; SUPERCONDUCTIVITY; OXIDATION; SYSTEM; OXIDE; SR AB SiO2 buffer layers as thin as 2 nm have been developed for use in the growth of Y1Ba2Cu3O6+delta thin films on silicon substrates. The SiO2 layers are formed through Y enhancement of silicon oxidation, and are highly stoichiometric. Y1Ba2Cu3O6+delta film growth on silicon with thin buffer layers has shown c orientation and T(c0) = 78 K. C1 NASA,JOHNSON SPACE CTR,HOUSTON,TX 77088. UNIV HOUSTON,CTR SPACE VACUUM EPITAXY,HOUSTON,TX 77204. RP ROBIN, T (reprint author), UNIV HOUSTON,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77204, USA. NR 22 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 28 PY 1991 VL 59 IS 18 BP 2323 EP 2325 DI 10.1063/1.106057 PG 3 WC Physics, Applied SC Physics GA GM040 UT WOS:A1991GM04000040 ER PT J AU JOHNSON, JR LARSON, SM SINGER, RB AF JOHNSON, JR LARSON, SM SINGER, RB TI REMOTE-SENSING OF POTENTIAL LUNAR RESOURCES .1. NEAR-SIDE COMPOSITIONAL PROPERTIES SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID REFLECTANCE SPECTRA; TITANIUM; CLASSIFICATION; DEPOSITS; GEOLOGY; SURFACE; ORIGIN; REGION; IRON; MOON AB New telescopic CCD multispectral imaging of the lunar near side and 330-870 nm spectroscopy of selected regions are presented as aids in estimating compositional differences relevant to locating potential lunar resources such as ilmenite (FeTiO3) and solar wind-implanted He-3 and H. Conversion of 400/560 nm CCD ratio images to weight percent TiO2 using a version of the Charette et al. (1974) empirical relation allows construction of a new TiO2 abundance map for the lunar maria accurate to +/- 2 wt % TiO2. This map provides a consistent view of TiO2 distribution among mature mare soils and can be used to estimate areas potentially rich in ilmenite. Western Mare Tranquillitatis exhibits the highest TiO2 abundances (> 8 wt %), followed by regions near Flamsteed P and in northern Oceanus Procellarum. A 950/560 nm CCD ratio mosaic of the full Moon provides estimates of relative surface maturity on local scales as defined by the degree of agglutinate production due to micrometeorite impacts. Since high He-3 concentrations are correlated with mature ilmenite-rich soils, a combination of relative surface maturity maps and TiO2 abundance maps may be useful for estimating He-3 (and possibly H) distribution on local scales. While dark mantle materials are also potential sources of ilmenite, He-3, and H, their compositional differences from mare soils prevent accurate remote mapping of their TiO2 abundance and relative maturity. Reflectance spectra (relative to a more rigorously defined MS-2 standard region) of dark mantle materials and high-TiO2 mare areas exhibit previously undocumented near-UV (< 350 nm) changes in spectral slope apparently related to compositional variations. Determination of the primary lunar sites for resource utilization will be dictated by the future goals and priorities of the lunar resource program. C1 UNIV ARIZONA,SPACE ENGN RES CTR UTILIZAT LOCAL PLANETARY RESOURCES,NASA,TUCSON,AZ 85721. RP JOHNSON, JR (reprint author), UNIV ARIZONA,PLANETARY IMAGE RES LAB,TUCSON,AZ 85721, USA. RI Johnson, Jeffrey/F-3972-2015 NR 83 TC 60 Z9 62 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-PLANET JI J. Geophys. Res.-Planets PD OCT 25 PY 1991 VL 96 IS E3 BP 18861 EP 18882 DI 10.1029/91JE02045 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GM166 UT WOS:A1991GM16600005 ER PT J AU PLESCIA, JB AF PLESCIA, JB TI GRABEN AND EXTENSION IN NORTHERN THARSIS, MARS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID CRUSTAL STRUCTURE; TECTONIC HISTORY; ALBA-PATERA; PROVINCE; REGION; LITHOSPHERE; TOPOGRAPHY; THICKNESS; MECHANICS; EVOLUTION AB A morphometric analysis of north-south trending graben at 35-degrees-N in northern Tharsis is used to provide the first quantitative measurements of crustal extension in and strain for areas of the Martian crust that have undergone both extreme and mild deformation. These estimates also demonstrate the viability of the Viking data for making such quantitative assessment. Graben in the region accommodate approximately 8 km of post Early Amazonian east-west extension. This extension corresponds to a net regional strain of 0.45-0.61%; local strains vary from < 1% to 5%. Extension is nonuniform and localized near 110-degrees (south of Alba Patera and north of Ceraunius Fossae) because of reactivation of preexisting fractures in underlying basement and possibly due to superposition of stress fields from Tharsis and Alba Patera. A major mechanical discontinuity in the shallow crust, probably representing the base of or a strength contrast within the megaregolith, is observed. It occurs at a depth of 2 km on the profile flanks and is depressed to about 7.5 km near 110-degrees due to loading of the crust by the volcano. A number of more shallow discontinuities occur within the construct and probably represent lithologic contacts. RP PLESCIA, JB (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,MAIL STOP 183501,PASADENA,CA 91109, USA. RI Plescia, Jeffrey/B-7738-2016 NR 44 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 25 PY 1991 VL 96 IS E3 BP 18883 EP 18895 DI 10.1029/91JE02005 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GM166 UT WOS:A1991GM16600006 ER PT J AU BLAKE, D ALLAMANDOLA, L SANDFORD, S HUDGINS, D FREUND, F AF BLAKE, D ALLAMANDOLA, L SANDFORD, S HUDGINS, D FREUND, F TI CLATHRATE HYDRATE FORMATION IN AMORPHOUS COMETARY ICE ANALOGS INVACUO SO SCIENCE LA English DT Article ID PHYSICO-CHEMICAL PHENOMENA; INFRARED-SPECTRA; SOLAR-SYSTEM; WATER; EROSION; OXIRANE; GRAINS; SNOWS AB The presence of clathrate hydrates in cometary ice has been suggested to account for anomalous gas release at large radial distances from the sun as well as the retention of volatiles in comets to elevated temperatures. However, how clathrate hydrates can form in low-pressure environments, such as in cold interstellar molecular clouds, in the outer reaches of the early solar nebula, or in cometary ices, has been poorly understood. Experiments performed with the use of a modified electron microscope demonstrate that during the warming of vapor-deposited amorphous ices in vacuo, clathrate hydrates can form by rearrangements in the solid state. Phase separations and microporous textures that are the result of these rearrangements may account for a variety of anomalous cometary phenomena. C1 NASA,AMES RES CTR,ASTROPHYS BRANCH,MOFFETT FIELD,CA 94035. SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95192. RP BLAKE, D (reprint author), NASA,AMES RES CTR,PLANETARY BIOL BRANCH,MAIL STOP 239-4,MOFFETT FIELD,CA 94035, USA. NR 35 TC 127 Z9 127 U1 2 U2 12 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD OCT 25 PY 1991 VL 254 IS 5031 BP 548 EP 551 DI 10.1126/science.11538372 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GL799 UT WOS:A1991GL79900042 PM 11538372 ER PT J AU GLEISER, M KOLB, EW WATKINS, R AF GLEISER, M KOLB, EW WATKINS, R TI PHASE-TRANSITIONS WITH SUBCRITICAL BUBBLES SO NUCLEAR PHYSICS B LA English DT Article ID EARLY UNIVERSE; INFLATIONARY UNIVERSE; FINITE TEMPERATURE; ELECTROWEAK THEORY; SYMMETRY-BREAKING; BARYON ASYMMETRY; FALSE VACUUM; DOMAIN-WALLS; HIGGS-BOSON; COSMOLOGY AB We study the dynamics of cosmological phase transitions initiated from a state of thermal equilibrium. If the effective potential satisfies certain general conditions, a homogeneous phase of false vacuum will form as the Universe expands, and the transition will proceed by well-known bubble nucleation processes. If such conditions do not hold, the Universe may instead be filled with a two-phase emulsion. The evolution of the transition will be determined by the free energy difference between the two phases and by the expansion rate of the Universe. Thermal fluctuations between the phases will determine the final distribution of regions of the Universe in each phase as they freeze out. We develop a method to study the dynamics of such fluctuations, which we call sub-critical bubbles, and apply it to several situations of interest, including the symmetric and asymmetric double-well, and the Coleman-Weinberg scalar potentials. We show that in certain cases it is possible to avoid supercooling, with the transition being completed by sub-critical fluctuations. Possible applications to the electroweak phase transition are briefly discussed. C1 UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106. FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. NR 63 TC 73 Z9 73 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD OCT 21 PY 1991 VL 364 IS 2 BP 411 EP 450 DI 10.1016/0550-3213(91)90592-L PG 40 WC Physics, Particles & Fields SC Physics GA GL798 UT WOS:A1991GL79800008 ER PT J AU SHAKLAN, S AF SHAKLAN, S TI SELECTIVE MODE INJECTION AND OBSERVATION FOR FEW-MODE FIBER OPTICS SO APPLIED OPTICS LA English DT Article DE FIBER OPTICS; MODES; HOLOGRAPHY ID MULTIMODE AB By etching the cladding along several millimeters of circular- or elliptical-core few-mode fiber optics, we gain access to the core and can inject extremely pure modes. The same etching technique allows one to measure the modal purity at the far end of the fiber. Modal purities of -26 dB have been obtained. We also demonstrate a holographic technique that allows all the light of each mode to be focused to an independent spot. C1 INST RECH COMMUN OPT & MICROONDES,CNRS,URA 356,F-87060 LIMOGES,FRANCE. RP SHAKLAN, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 169-214,PASADENA,CA 91109, USA. NR 12 TC 19 Z9 19 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD OCT 20 PY 1991 VL 30 IS 30 BP 4379 EP 4383 PG 5 WC Optics SC Optics GA GQ421 UT WOS:A1991GQ42100020 PM 20717213 ER PT J AU AITKEN, DK GEZARI, D SMITH, CH MCCAUGHREAN, M ROCHE, PF AF AITKEN, DK GEZARI, D SMITH, CH MCCAUGHREAN, M ROCHE, PF TI POLARIMETRIC IMAGING OF THE GALACTIC-CENTER AT 12.4 MICRONS - THE DETAILED MAGNETIC-FIELD STRUCTURE IN THE NORTHERN ARM AND EAST-WEST BAR SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, NUCLEI; GALAXIES, THE GALAXY; INTERSTELLAR, MAGNETIC FIELDS; POLARIZATION ID NE-II OBSERVATIONS; INFRARED SPECTROPOLARIMETRY; CENTRAL PARSEC; GALAXY; ALIGNMENT AB We present new closely sampled (approximately 1") imaging polarimetry of the central 0.5 pc of the Galaxy at 12.4-mu-m with a 58 x 62 array camera system. The image shows a much more detailed view of the morphology of the intrinsically polarized emission (and the associated aligning magnetic field) in the ionized filaments of the Sgr A West complex than has been possible with earlier single beam studies. The new results show that the magnetic field in the northern arm is continuous on 1" scale and is a property of the filamentary structure rather than the compact peaks of infrared emission and that it continues in a southwesterly direction from IRS 1 for several arcseconds into the east-west bar. In the southern and western part of the east-west bar the intrinsic polarization becomes complex, with small-scale variations of polarization fraction and position angle, probably due to superposition of different field directions along the line of sight. There is no evidence of perturbation of the field structure by the energetic outflows from the IRS 16 complex, and it is concluded that IRS 16 does not lie in the plane of the northern arm, and that it cannot be at the center of the mass distribution of the Sgr A West system. We consider that the magnetic field in Sgr A West is amplified due to shearing motions in the ionized material and that the direction of the field is that of the flow. The run of magnetic field directions in the inner rim of the northern arm and east west bar then indicate a flow pattern which shows striking symmetry about the position of Sgr A*. When earlier data from outside the image area are included, an elliptical flow pattern with focus close to Sgr A* is indicated. C1 UNIV OXFORD,DEPT ASTROPHYS,OXFORD OX1 3RH,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,INFRARED ASTROPHYS BRANCH,GREENBELT,MD 20771. RP AITKEN, DK (reprint author), UNIV NEW S WALES,AUSTRALIAN DEF FORCE ACAD,UNIV COLL,DEPT PHYS,ACT 2600,AUSTRALIA. OI Roche, Patrick/0000-0002-8524-8413 NR 42 TC 43 Z9 43 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 OCT 20 PY 1991 VL 380 IS 2 BP 419 EP 428 DI 10.1086/170600 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GJ954 UT WOS:A1991GJ95400013 ER PT J AU WANNIER, PG ANDERSSON, BG OLOFSSON, H UKITA, N YOUNG, K AF WANNIER, PG ANDERSSON, BG OLOFSSON, H UKITA, N YOUNG, K TI ABUNDANCES IN RED GIANT STARS - NITROGEN ISOTOPES IN CARBON-RICH MOLECULAR ENVELOPES SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, ABUNDANCES; STARS, CARBON; STARS, CIRCUMSTELLAR SHELLS; STARS, LATE-TYPE ID INTER-STELLAR MEDIUM; LABORATORY DETECTION; MASER EMISSION; GALACTIC DISK; IRC+10216; OXYGEN; INTERSTELLAR; EVOLUTION; SEARCHES; OUTFLOW AB Millimeter- and submillimeter-wave observations of HCN and HCCCN have been made of the circumstellar envelopes of eight carbon stars, including the two protoplanetary nebulae: CRL 618 and CRL 2688. The observations yield a measure of the double ratio: N-14-C-13/N-15-C-12. By using measured C-12/C-13 ratios, we estimate the N-14/N-15 abundance ratio, with resulting lower limits in all eight envelopes and possible direct determinations in two envelopes. The two determinations, and four of the remaining six lower limits are in excess of the terrestrial value of N-14/N-15 = 272, indicating an evolution of the nitrogen isotope ratio, consistent with stellar CNO processing. Observations of thermal SiO (v = 0, J = 2-1) emission show that the Si-29/Si-28 ratio can be determined in carbon stars, and further observations are indicated. C1 ONSALA SPACE OBSERV,S-43900 ONSALA,SWEDEN. NOBEYAMA RADIO OBSERV,MINAMISA,NAGANO 38413,JAPAN. GOTHENBURG UNIV,DEPT ASTRON & ASTROPHYS,S-41296 GOTHENBURG,SWEDEN. CALTECH,DEPT ASTRON,PASADENA,CA 91106. RP WANNIER, PG (reprint author), CALTECH,JET PROP LAB,MS 169-506,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 50 TC 27 Z9 27 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 1991 VL 380 IS 2 BP 593 EP 605 DI 10.1086/170616 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GJ954 UT WOS:A1991GJ95400029 ER PT J AU GRIGSBY, JA AF GRIGSBY, JA TI A NONLOCAL THERMODYNAMIC-EQUILIBRIUM, LINE-BLANKETED SYNTHETIC SPECTRUM OF IOTA HERCULIS - C, AL, AND SI LINES SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, ABUNDANCES; STARS, ATMOSPHERES; STARS, EARLY-TYPE; ULTRAVIOLET, SPECTRA ID STARS AB Using the non-LTE, line-blanketed model stellar atmosphere developed by Anderson, I have computed a model of l Herculis (B3 IV) with T(eff) = 17,500 K and log g = 3.75, following the conclusions of Peters and Polidan. The model contains lines of H, He, C, N, O, Ne, Al, and Si. An opacity sampling technique allows for the inclusion of the lines of species Sc-Ni. Detailed profiles of a number of lines of C, Al, and Si in the 1200-2000 angstrom region were computed, including the resonance lines of C II, Al II, and Al III. These profiles were compared to observations obtained from the co-addition of eight IUE SWP images, using a technique developed by Leckrone and Adelman. Agreement between a model with solar abundances and observations is generally good in the Al and Si lines. Comparison of carbon lines with a model that is underabundant in carbon by a factor of 2 relative to the Sun indicates that the C abundance of l Her is at most one-half solar. The model Si II lines of the p2 2D-3d' 2F-degrees multiplet are much weaker than the observed lines. The discrepancy appears to be due to autoionization in the upper levels of those lines, an effect not accounted for in the model. Additional comparison of synthetic lines of H-gamma, He I lambda-4471, and Mg II lambda-4481 with observations also yield good agreement, showing the ability of the code to reproduce the spectra of many species over a wide range of wavelengths. Non-LTE effects were examined by comparing an LTE model (possessing identical atmospheric parameters) with the non-LTE model. Substantial differences in the populations of the model atomic states are seen, but differences in the temperature structure of the two models often mask the non-LTE effects in the synthetic spectra. In general, non-LTE effects in a given transition are difficult to predict, and should be examined on a case-by-case basis. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. NR 29 TC 10 Z9 10 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 OCT 20 PY 1991 VL 380 IS 2 BP 606 EP 616 DI 10.1086/170617 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GJ954 UT WOS:A1991GJ95400030 ER PT J AU JENSEN, EJ THOMAS, GE AF JENSEN, EJ THOMAS, GE TI CHARGING OF MESOSPHERIC PARTICLES - IMPLICATIONS FOR ELECTRON-DENSITY AND PARTICLE COAGULATION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NOCTILUCENT CLOUDS; LOWER THERMOSPHERE; SUMMER MESOPAUSE; AMORPHOUS ICE; REGION; STATE; MODEL; IONS; DUST AB Measurements of the electron density at high latitudes in the summertime show a pronounced "bite-out" at about 87 km. Using a numerical model of polar mesospheric cloud (PMC) formation. we have investigated the effects of ion and electron capture by ice particles on the ionization near the mesopause. The microphysical model includes all physical processes believed to be important, and the predicted PMC optical properties agree well with polarization and albedo measurements. We have calculated statistical distributions of charges on ice particles, including collection of ions and electrons by particles, and photoemission. Given these charge distributions, ionization loss rates due to capture by particles and the resulting steady-state electron and ion densities are calculated. Our calculations indicate that aerosol concentrations associated with visible PMC are unlikely to cause a severe electron density depletion. The bite-out could possibly be caused by a large concentration of small ice particles existing in a narrow cold layer near the mesopause. However, concentrations of ice nuclei (either dust particles or water cluster ions) on the order of 1000 cm-3 would be required. We have also found that the net negative charge on mesospheric aerosols may severely inhibit coagulation. The importance of this result is that mesospheric dust particles would not grow significantly. If this analysis is indeed correct, then mesospheric dust particles will be smaller than previously estimated, and a higher supersaturation with respect to water vapor would be required for heterogeneous nucleation of ice crystals. Hence, the existence of ice particles at the mesopause may require lower temperatures than previously assumed. C1 UNIV COLORADO, ATMOSPHER & SPACE PHYS LAB, BOULDER, CO 80309 USA. RP JENSEN, EJ (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 33 TC 67 Z9 68 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD OCT 20 PY 1991 VL 96 IS D10 BP 18603 EP 18615 DI 10.1029/91JD01966 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GM167 UT WOS:A1991GM16700006 ER PT J AU BAUSCHLICHER, CW LANGHOFF, SR AF BAUSCHLICHER, CW LANGHOFF, SR TI QUANTUM-MECHANICAL CALCULATIONS TO CHEMICAL ACCURACY SO SCIENCE LA English DT Article ID BOND-DISSOCIATION ENERGY; CONFIGURATION-INTERACTION CALCULATIONS; ANHARMONIC POTENTIAL FUNCTION; HERMAN INFRARED SYSTEM; GAUSSIAN-BASIS SETS; ELECTRON CORRELATION; ABINITIO CALCULATIONS; MOLECULAR-ENERGIES; GROUND-STATE; ACETYLENE AB Full configuration-interaction (FCI) calculations have given an unambiguous standard by which the accuracy of theoretical approaches of incorporating electron correlation into molecular structure calculations can be judged. In addition, improvements in vectorization of programs, computer technology, and algorithms now permit a systematic study of the convergence of the atomic orbital (or so-called one-particle) basis set. These advances are discussed and some examples of the solution of chemical problems by quantum mechanical calculations are given to illustrate the accuracy of current techniques. RP NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 63 TC 39 Z9 39 U1 0 U2 11 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD OCT 18 PY 1991 VL 254 IS 5030 BP 394 EP 398 DI 10.1126/science.254.5030.394 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GK729 UT WOS:A1991GK72900037 PM 17742225 ER PT J AU KOJIRO, DR COHEN, MJ STIMAC, RM WERNLUND, RF HUMPHRY, DE TAKEUCHI, N AF KOJIRO, DR COHEN, MJ STIMAC, RM WERNLUND, RF HUMPHRY, DE TAKEUCHI, N TI DETERMINATION OF C1-C4 ALKANES BY ION MOBILITY SPECTROMETRY SO ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION DETECTOR AB Flight instrumentation for the analyses of extraterrestrial environments must often perform under severely restricted conditions. Often, the detection and identification of a multitude of chemical species is required to fulfill the scientific objectives of the mission. It is therefore important that the analytical instrumentation have universal response. The gas chromatography-ion mobility spectrometer (GC-IMS) has the potential to provide the sample separation, identification and sensitivity necessary for a successful analysis. However, the IMS has poor sensitivity for the C1-C4 alkanes. The abundance of these molecules at various extraterrestrial sites is often of great importance to exobiologists. This study focuses on optimizing IMS sample ionization mechanisms for the C1-C4 alkanes and other hydrocarbons of interest to exobiology. C1 PCP INC,W PALM BEACH,FL 33409. SETI INST,MT VIEW,CA 94043. TMA NORCAL,RICHMOND,CA 94804. RP KOJIRO, DR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 15 TC 15 Z9 16 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 15 PY 1991 VL 63 IS 20 BP 2295 EP 2300 DI 10.1021/ac00020a019 PG 6 WC Chemistry, Analytical SC Chemistry GA GJ962 UT WOS:A1991GJ96200019 PM 11538291 ER PT J AU LANGHOFF, SR BAUSCHLICHER, CW AF LANGHOFF, SR BAUSCHLICHER, CW TI THEORETICAL-STUDY OF THE SPECTROSCOPY OF B2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID IONIZATION-POTENTIALS; ELECTRONIC-STRUCTURE; DISSOCIATION-ENERGY; B-2; ABINITIO; ATOMS; AL2 AB The singlet, triplet, and quintet states of B2 below about 45 000 cm-1 have been studied at the multireference configuration-interaction (MRCI) level in a [4s 3p 2d 1f] atomic natural orbital (ANO) Gaussian basis set. Calculations employing a [5s 4p 3d 2f 1g] ANO basis were also performed for the low-lying states, X 3-SIGMA-g-, A 3-PI-u, a 5-SIGMA-u-, b 1-DELTA-g, and c 1-SIGMA-g+, to assess the accuracy of the spectroscopic constants determined with the smaller basis and to position the singlet, triplet, and quintet manifolds as accurately as possible. Our best estimate of the T(e) value for the a 5-SIGMA-u- state is 1701 cm-1. A D0 value is computed for the X 3-SIGMA-g- state of B2 of 2.78 eV and estimate that D0 is 2.85 +/- 0.06 in the complete CI limit. This value is within the error bars of the rather uncertain JANAF value, but is larger than the value of 2.71 eV determined recently using the G1 approach. Einstein coefficients are presented for selected triplet-triplet transitions, and radiative lifetimes for the triplet states to help characterize the optical spectra. Finally the potential energy curves of B2 are compared to those determined in an analogous manner for Al2. RP LANGHOFF, SR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 26 TC 63 Z9 63 U1 0 U2 3 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 OCT 15 PY 1991 VL 95 IS 8 BP 5882 EP 5888 DI 10.1063/1.461609 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200038 ER PT J AU MIELKE, SL TRUHLAR, DG SCHWENKE, DW AF MIELKE, SL TRUHLAR, DG SCHWENKE, DW TI IMPROVED TECHNIQUES FOR OUTGOING WAVE VARIATIONAL PRINCIPLE CALCULATIONS OF CONVERGED STATE-TO-STATE TRANSITION-PROBABILITIES FOR CHEMICAL-REACTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MECHANICAL REACTION PROBABILITIES; POTENTIAL-ENERGY SURFACE; QUANTAL SCATTERING CALCULATIONS; CONTRACTED BASIS FUNCTIONS; ADIABATIC BASIS FUNCTIONS; LOG-DERIVATIVE MATRIX; CROSS-SECTIONS; ANGULAR-MOMENTUM; ROTATIONAL-EXCITATION; MOLECULE COLLISIONS AB We present improved techniques and well-optimized basis sets for application of the outgoing wave variational principle to calculate converged quantum mechanical reaction probabilities, and we illustrate them with calculations for the reactions D + H-2 --> HD + H with total angular momentum J = 3 and F + H-2 --> HF + H with J = 0 and 3. The optimization involves the choice of distortion potential, the grid for calculating half-integrated Green's functions, the placement, width, and number of primitive distributed Gaussians, and the computationally most efficient partition between dynamically adapted and primitive basis functions. We present benchmark calculations with 224-1064 channels. C1 UNIV MINNESOTA,INST SUPERCOMP,MINNEAPOLIS,MN 55455. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP MIELKE, SL (reprint author), UNIV MINNESOTA,DEPT CHEM,CHEM PHYS PROGRAM,MINNEAPOLIS,MN 55455, USA. RI Mielke, Steven/B-7533-2008; schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Mielke, Steven/0000-0002-1938-7503; Truhlar, Donald/0000-0002-7742-7294 NR 60 TC 22 Z9 22 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 OCT 15 PY 1991 VL 95 IS 8 BP 5930 EP 5939 DI 10.1063/1.461614 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200043 ER PT J AU WILSON, MA POHORILLE, A AF WILSON, MA POHORILLE, A TI INTERACTION OF MONOVALENT IONS WITH THE WATER LIQUID VAPOR INTERFACE - A MOLECULAR-DYNAMICS STUDY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID THERMODYNAMIC PROPERTIES; ORIENTATIONAL STRUCTURE; SIMULATION; MEMBRANES; HYDRATION; MODEL; BOUNDARY; MOBILITY; SURFACE; MOTION AB Results of molecular dynamics studies on the ions Na+,F-, and Cl- near the water liquid-vapor interface are reported. The free energies required to move the ions to the interface are presented and shown to depend on the sign of the ionic charge, and not the size of the ion. F- and Cl- can approach to within 2 molecular layers of the interface without incurring a significant change in free energy, while it costs about 2.5 kcal/mole to move Na+ this same distance. The free energy differences between the cation and the anions arise from the interaction of the ions with the water molecules in the interfacial region. These water molecules are oriented with a slight preference for their molecular dipoles to point toward the liquid. Thus, the anion approaching the interface disrupt the water structures less than does the cation. The calculated free energy curves are compared with predictions of simple dielectric models. It is shown that these models do not provide a good description of ions at the water surface. The ions are found to retain their solvation shells at the interface. The anions also retain part of their second solvation shells, while Na+ does not. As a result, a larger bulge in the water surface is observed above the anions than above Na+. The lateral mobilities of the ions increase at the interface, in qualitative agreement with predictions of hydrodynamic models. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP WILSON, MA (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. FU NCI NIH HHS [NCA-2 315] NR 45 TC 117 Z9 117 U1 1 U2 9 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 OCT 15 PY 1991 VL 95 IS 8 BP 6005 EP 6013 DI 10.1063/1.461592 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200051 PM 11538294 ER PT J AU SALAMA, F ALLAMANDOLA, LJ AF SALAMA, F ALLAMANDOLA, LJ TI THE ROLE OF MATRIX MATERIAL AND CCL4 (ELECTRON-ACCEPTOR) ON THE IONIZATION MECHANISMS OF MATRIX-ISOLATED NAPHTHALENE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID AROMATIC-MOLECULES; PHOTO-IONIZATION; SOLID ARGON; RESONANCE; SPECTRA; CATION RP SALAMA, F (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 2456,MOFFETT FIELD,CA 94035, USA. RI Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 14 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1991 VL 95 IS 8 BP 6190 EP 6191 DI 10.1063/1.461827 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200073 PM 11538295 ER PT J AU DILL, LH AF DILL, LH TI ON THE THERMOCAPILLARY MIGRATION OF A GROWING OR SHRINKING DROP SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article ID VERTICAL TEMPERATURE-GRADIENT; PLANE SURFACE; BUBBLES C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 14 TC 2 Z9 2 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 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD OCT 15 PY 1991 VL 146 IS 2 BP 533 EP 540 DI 10.1016/0021-9797(91)90217-V PG 8 WC Chemistry, Physical SC Chemistry GA GG640 UT WOS:A1991GG64000023 ER PT J AU NOEVER, DA AF NOEVER, DA TI EVOLUTION OF BIOCONVECTIVE PATTERNS IN VARIABLE GRAVITY SO PHYSICAL REVIEW A LA English DT Article ID GYROTACTIC MICROORGANISMS; SWIMMING MICROORGANISMS; SOAP; DYNAMICS; CELLS; MODEL; SPERMATOZOA; MONOLAYERS; SUSPENSION; PROPULSION AB Measurements are reported of the evolution of bioconvective patterns in shallow, dense cultures of microorganisms subjected to varying gravity. Various statistical properties of this random, quasi-two-dimensional structure have been found: Aboav's law is obeyed, the average vertex angles follow predictions for regular polygons, and the area of a pattern varies linearly with its number of sides. As gravity varies between 1 g and 1.8g (g = 9.8 m s-1), these statistical properties continue to hold despite a tripling of the number of polygons and a reduced average polygon dimension by a third. This work compares with experiments on soap foams, Langmuir monolayer foams, metal grains, and simulations. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES76,HUNTSVILLE,AL 35812, USA. NR 45 TC 8 Z9 8 U1 1 U2 3 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 OCT 15 PY 1991 VL 44 IS 8 BP 5279 EP 5291 DI 10.1103/PhysRevA.44.5279 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000056 PM 9906580 ER PT J AU KRISHER, TP AF KRISHER, TP TI PULSAR POLARIZATION MEASUREMENTS AND THE NONSYMMETRIC GRAVITATIONAL THEORY SO PHYSICAL REVIEW D LA English DT Note ID WEAK EQUIVALENCE PRINCIPLE; MODE FREQUENCY SPLITTINGS; VIOLATION; GRAVITY AB Because of the breakdown of the Einstein equivalence principle in the nonsymmetric gravitational theory (NGT) of Moffat, orthogonally polarized electromagnetic waves can propagate at different velocities in a gravitational field. Moffat has proposed that galactic dark matter, in the form of cosmions, may act as a significant source of gravity in the NGT. We discuss how observations of the highly polarized radiation from distant pulsars could provide significant limits on the strength of the coupling of cosmions in the NGT. RP KRISHER, TP (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 16 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 15 PY 1991 VL 44 IS 8 BP R2211 EP R2213 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GL467 UT WOS:A1991GL46700001 ER PT J AU LEWIS, ML NACHTWEY, DS DAMRON, KL AF LEWIS, ML NACHTWEY, DS DAMRON, KL TI A MINIATURIZED FIBRINOLYTIC ASSAY FOR PLASMINOGEN ACTIVATORS SO THROMBOSIS RESEARCH LA English DT Article DE FIBRINOLYTIC; KINETIC; PLASMINOGEN ACTIVATORS; MICROASSAY ID MOLECULAR-WEIGHT UROKINASE; SPECTROPHOTOMETRIC ASSAY; PORCINE; PLASMA AB This report describes a micro-clot lysis assay (MCLA) for evaluating fibrinolytic activity of plasminogen activators (PA). Fibrin clots were formed in wells of microtiter plates. Lysis of the clots by PA, indicated by change in turbidity (optical density, OD), was monitored with a microplate reader at five minute intervals. Log-log plots of PA dilution versus endpoint, the time at which the OD value was halfway between the maximum and minimum value for each well, were linear over a broad range of PA concentrations (2-200 international units/ml). The MCLA is a modification and miniaturization of well established fibrinolytic methods. The significant practical advantages of the MCLA are that it is a simple, relatively sensitive, non-radioactive, quantitative, kinetic, fibrinolytic micro-technique which can be automated. C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. KRUG LIFE SCI,HOUSTON,TX 77058. NR 29 TC 17 Z9 17 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0049-3848 J9 THROMB RES JI Thromb. Res. PD OCT 15 PY 1991 VL 64 IS 2 BP 223 EP 234 DI 10.1016/0049-3848(91)90121-C PG 12 WC Hematology; Peripheral Vascular Disease SC Hematology; Cardiovascular System & Cardiology GA GR565 UT WOS:A1991GR56500009 PM 1811341 ER PT J AU SWANK, PR LEWIS, ML DAMRON, KL AF SWANK, PR LEWIS, ML DAMRON, KL TI A COMPUTER-PROGRAM FOR MICROPLATE READER INTERFACE AND ANALYSIS OF KINETIC, MICROCLOT LYSIS ASSAYS SO THROMBOSIS RESEARCH LA English DT Article DE APPLE-IIE PROGRAM; MICROPLATE READER; BIO-TEK EL310; KINETIC ASSAY AB This paper describes the development and use of a program for the APPLE LLe computer which records and analyzes data from an automated microplate reader for the purpose of determining the time required for clots formed in microplate wells to half lyse as determined by optical density readings. The use of this software has led to significant savings of technician time over that required for nonautomated systems. C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. KRUG LIFE SCI,HOUSTON,TX 77058. RP SWANK, PR (reprint author), UNIV HOUSTON,DEPT EDUC PSYCHOL,UNIV PK,HOUSTON,TX 77004, USA. NR 2 TC 1 Z9 1 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0049-3848 J9 THROMB RES JI Thromb. Res. PD OCT 15 PY 1991 VL 64 IS 2 BP 235 EP 242 DI 10.1016/0049-3848(91)90122-D PG 8 WC Hematology; Peripheral Vascular Disease SC Hematology; Cardiovascular System & Cardiology GA GR565 UT WOS:A1991GR56500010 PM 1811342 ER PT J AU LARSSON, A MASERJIAN, J AF LARSSON, A MASERJIAN, J TI OPTICALLY INDUCED EXCITONIC ELECTROABSORPTION IN A PERIODICALLY DELTA-DOPED INGAAS/GAAS MULTIPLE QUANTUM-WELL STRUCTURE SO APPLIED PHYSICS LETTERS LA English DT Article ID MQW STRUCTURES; SUPERLATTICES; ABSORPTION AB Large optically induced Stark shifts have been observed in a periodically delta-doped InGaAs/GaAs multiple quantum well structure. With an excitation intensity of 10 mW/cm2 we have measured an absolute quantum well absorption change of 7000 cm-1 with a corresponding differential absorption change as high as 80%. The associated maximum change in the quantum well refractive index is 0.04. This material is promising for device development for all-optical computing and signal processing. RP LARSSON, A (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 15 TC 21 Z9 21 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 OCT 14 PY 1991 VL 59 IS 16 BP 1946 EP 1948 DI 10.1063/1.106144 PG 3 WC Physics, Applied SC Physics GA GJ638 UT WOS:A1991GJ63800009 ER PT J AU SIMON, T LANDSMAN, W AF SIMON, T LANDSMAN, W TI THE ONSET OF CHROMOSPHERIC ACTIVITY AMONG THE A-STARS AND F-STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, CHROMOSPHERES; STARS, WINDS; ULTRAVIOLET, SPECTRA ID MAIN-SEQUENCE STARS; DELTA-SCUTI; CONVECTION ZONES; CORONAL ACTIVITY; ACOUSTIC ENERGY; EVOLUTION; EMISSION; GENERATION; ROTATION; LIMITS AB We show, from measurements of C II 1335 angstrom in several hundred low-resolution IUE spectra, that strong chromospheric emission is common among early F dwarf and subgiant stars. At its brightest, the emission is equal to that of the most active solar-type stars and is exceeded only by that of the spotted RS CVn and BY Dra variables. We find some evidence to suggest that the emission from main-sequence stars reaches a peak near B-V = 0.28, in the vicinity of spectral type F0 V, before it declines to lower flux levels among the late A stars. Emission is seen in some dwarf stars as early as B-V = 0.25. A regression calculation that takes proper account of upper limits in the observed flux demonstrates that the C II emission of stars earlier than spectral type F5 is uncorrelated with rotation. This result lends support to idea that the chromospheres of the late A and early F stars are heated by the shock dissipation of sound waves. However, the UV emission of some stars just shortward of B-V = 0.28 appears to fall off much more quickly than expected from theoretical predictions of the acoustic energy generated by convection. A faster decline may be possible if in some stars the onset of convection is suppressed or if the sound waves emerging from the top of the convection zone are subject to strong radiation damping below the chromosphere. We confirm previous findings, based on measurements of C IV, that the coronal X-ray:chromospheric UV flux ratio is lower for stars earlier than spectral type F5 than for those later than F5. We interpret this as evidence that the late A and early F stars have strong coronal winds. C1 NASA,GODDARD SPACE FLIGHT CTR,ST SYST CORP,GREENBELT,MD 20771. RP SIMON, T (reprint author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA. NR 32 TC 56 Z9 56 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 OCT 10 PY 1991 VL 380 IS 1 BP 200 EP 207 DI 10.1086/170574 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH912 UT WOS:A1991GH91200020 ER PT J AU WEBBER, WR GOLDEN, RL STOCHAJ, SJ ORMES, JF STRITTMATTER, RE AF WEBBER, WR GOLDEN, RL STOCHAJ, SJ ORMES, JF STRITTMATTER, RE TI A MEASUREMENT OF THE COSMIC-RAY H-2 AND HE-3 SPECTRA AND H-2/HE-4 AND HE-3/HE-4 RATIOS IN 1989 SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC RAYS, ABUNDANCES; PARTICLE ACCELERATION AB We have measured the energy spectra of H-2 and He-3 nuclei up to energies of 450 and 800 MeV nucleon, respectively, during a balloon flight of the NASA/NMSU Balloon Borne Magnet Facility on 1989 September 5. These isotopes were cleanly resolved from the more abundant H-1 and He-4 using a measurement of rigidity versus velocity as measured in a high-resolution scintillation counter. After correction for atmospheric secondaries the measured H-2/He-4 and He-3/He-4 ratios are both consistent with the production expected if H-1 and He-4 have the same path length in the galaxy as heavier cosmic-ray nuclei such as C and Fe, to within approximately 20%. Solar modulation effects play an important role in this uncertainty. This result favors a generally similar propagation history, along with similar types of sources for H-1 and He-4 and the heavier cosmic-ray nuclei. C1 NEW MEXICO STATE UNIV,PARTICLE ASTROPHYS LAB,LAS CRUCES,NM 88003. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP WEBBER, WR (reprint author), NEW MEXICO STATE UNIV,DEPT ASTRON,BOX 30001,DEPT 4500,LAS CRUCES,NM 88003, USA. NR 17 TC 42 Z9 42 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 OCT 10 PY 1991 VL 380 IS 1 BP 230 EP 234 DI 10.1086/170578 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH912 UT WOS:A1991GH91200024 ER PT J AU REAMES, DV KALLENRODE, MB STONE, RG AF REAMES, DV KALLENRODE, MB STONE, RG TI MULTISPACECRAFT OBSERVATIONS OF SOLAR HE-3-RICH EVENTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, FLARES; SUN, PARTICLE EMISSION; SUN, RADIO RADIATION ID PARTICLE EVENTS; ELECTRON EVENTS; ISEE-C AB We report on a systematic search of He isotope observations on the Helios 1 and 2 spacecraft during the occurrence of 66 He-3-rich time periods observed on ISEE 3 over a 4 yr interval. Seven time periods show possible event associations but only three show confirmed events with similar He-3/He-4 ratios on Helios and ISEE 3. We use kilometric radio observations of type III bursts produced by electrons associated with the He-3-rich events to map the interplanetary field lines outward from the events. The observations are best explained in terms of a narrow cone of emission of the particles from these events. C1 UNIV KIEL,INST REINE & ANGEW KERNPHYS,W-2300 KIEL 1,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP REAMES, DV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 661,GREENBELT,MD 20771, USA. NR 20 TC 19 Z9 19 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 1991 VL 380 IS 1 BP 287 EP 292 DI 10.1086/170585 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH912 UT WOS:A1991GH91200031 ER PT J AU KENNY, TW KAISER, WJ WALTMAN, SB REYNOLDS, JK AF KENNY, TW KAISER, WJ WALTMAN, SB REYNOLDS, JK TI NOVEL INFRARED DETECTOR BASED ON A TUNNELING DISPLACEMENT TRANSDUCER SO APPLIED PHYSICS LETTERS LA English DT Article ID MICROSCOPY; SENSOR AB The pneumatic infrared detector [M. J. E. Golay, Rev. Sci. Instrum. 18, 347 (1947)] uses thermal expansion of a gas to detect infrared radiation. We have designed a detector based on this principle, but which is constructed entirely from micromachined silicon, and uses an electron tunneling displacement transducer to detect the expansion of the gas. The design, fabrication, and characterization of the first prototype sensor are described. Its sensitivity is competitive with the best available uncooled infrared detectors. RP KENNY, TW (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 19 TC 38 Z9 40 U1 3 U2 7 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 OCT 7 PY 1991 VL 59 IS 15 BP 1820 EP 1822 DI 10.1063/1.106209 PG 3 WC Physics, Applied SC Physics GA GJ107 UT WOS:A1991GJ10700004 ER PT J AU PARTRIDGE, H STALLCOP, JR LEVIN, E AF PARTRIDGE, H STALLCOP, JR LEVIN, E TI TRANSPORT CROSS-SECTIONS AND COLLISION INTEGRALS FOR N(S-4(0))-O+(S-4(0)) AND N+(P-3)-O(P-3) INTERACTIONS SO CHEMICAL PHYSICS LETTERS LA English DT Article AB The transport cross sections and collision integrals are reported for the N+-O and N-O+ interactions. The cross sections are determined using accurate potential energy curves and a semiclassical description of the scattering. The computed collision integrals differ substantially from the estimated values currently recommended for flow-field studies. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. RP PARTRIDGE, H (reprint author), NASA,AMES RES CTR,DIV THERMOSCI,COMPUTAT CHEM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 16 TC 14 Z9 14 U1 0 U2 3 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 OCT 4 PY 1991 VL 184 IS 5-6 BP 505 EP 512 DI 10.1016/0009-2614(91)80026-T PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GK130 UT WOS:A1991GK13000026 ER PT J AU NESBITT, FL MARSTON, G STIEF, LJ WICKRAMAARATCHI, MA TAO, W KLEMM, RB AF NESBITT, FL MARSTON, G STIEF, LJ WICKRAMAARATCHI, MA TAO, W KLEMM, RB TI MEASUREMENT OF THE PHOTOIONIZATION SPECTRA AND IONIZATION THRESHOLDS OF THE H2CN AND D2CN RADICALS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID INTER-STELLAR CLOUDS; ELECTRONIC-SPECTRA; HCN; CHEMISTRY; HYDROGEN; CONSTANT; BEARING; ISOMERS; RATIOS; ION AB The photoionization spectra of the H2CN and D2CN radicals were obtained by photoionization mass spectrometry (PIMS) using synchrotron radiation. The radicals were generated by the reaction of N with CH3 and CD3, respectively. For both H2CN and D2CN a prominent feature was observed near 118.6 nm (10.5 eV) and the ionization threshold was determined to be 9.4 +/- 0.1 eV; both features provide additional signatures for identifying H2CN in complex systems. By use of a corrected value for DELTA-H(f) (H2CN) derived from a recent electron affinity measurement and other available measured or calculated thermochemical quantities for H2CN and HCNH radicals and radical ions, a value of 10.8 +/- 0.6 eV for the ionization energy of H2CN was derived. The much lower value derived for the ionization energy of HCNH (6.8 and 7.0 eV for the cis and trans isomers, respectively) is consistent with the product of the N + CH3 reaction being the H2CN isomer and not HCNH. The ionization threshold observed at 9.4 eV is attributed to autoionization arising from high Rydberg states of H2CN which couple into vibrationally excited states of the linear HCNH+ ground state of the ion. Also discussed are the roles of the H2CN radical and HCNH+ radical ion in the chemistry of the atmosphere of Titan and in interstellar clouds. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,ASTROCHEM BRANCH,GREENBELT,MD 20771. BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RI Marston, George/J-9223-2012; Marston, George/B-3116-2015 OI Marston, George/0000-0002-0050-5928; Marston, George/0000-0002-0050-5928 NR 47 TC 34 Z9 34 U1 0 U2 7 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 OCT 3 PY 1991 VL 95 IS 20 BP 7613 EP 7617 DI 10.1021/j100173a012 PG 5 WC Chemistry, Physical SC Chemistry GA GH893 UT WOS:A1991GH89300012 ER PT J AU LEU, MT MOORE, SB KEYSER, LF AF LEU, MT MOORE, SB KEYSER, LF TI HETEROGENEOUS REACTIONS OF CHLORINE NITRATE AND HYDROGEN-CHLORIDE ON TYPE-I POLAR STRATOSPHERIC CLOUDS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID NITRIC-ACID TRIHYDRATE; OZONE HOLE; HCL; TEMPERATURES; KINETICS; ICE AB The heterogeneous reactions ClONO2 + HCl --> Cl2 + HNO3 (1) and ClONO2 + H2O --> HOCl + HNO3 (2) on vapor-deposited HNO3-H2O ice substrates have been investigated at 196 K by using a fast-flow reactor coupled with a quadrupole mass spectrometer. The reaction probability for (1) is 0.10 +/- 0.02 and independent of both the HNO3 and HCl concentrations in the substrate compositions studied. For (2), the reaction probability is approximately 1 x 10(-5) near 53.8 wt % HNO3, the composition of pure nitric acid trihydrate (NAT), and is about 1 x 10(-3) at 46 wt % HNO3. The sticking coefficient of HCl on these substrates was also found to be a strong function of the substrate composition, ranging from about 2 x 10(-5) at NAT composition to 6 x 10(-3) at 45 wt % HNO3. The HNO3-H2O ice substrates were found to have large internal surface areas, and corrections for gas-phase diffusion within the porous ices were applied to observed loss rates. The large decrease in the HCl sticking coefficient and the reaction probability for (2) as the composition of pure NAT is approached from the water-enriched side can be semiquantatively explained in terms of a simple two-solid-phase model. Finally, the relation of these results to the depletion of polar ozone is discussed. RP LEU, MT (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 28 TC 74 Z9 74 U1 0 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 OCT 3 PY 1991 VL 95 IS 20 BP 7763 EP 7771 DI 10.1021/j100173a040 PG 9 WC Chemistry, Physical SC Chemistry GA GH893 UT WOS:A1991GH89300040 ER PT J AU HUANG, YQ HILL, YD SODUPE, M BAUSCHLICHER, CW FREISER, BS AF HUANG, YQ HILL, YD SODUPE, M BAUSCHLICHER, CW FREISER, BS TI CHEMISTRY OF THE SCANDIUM BENZYNE ION IN THE GAS-PHASE SO INORGANIC CHEMISTRY LA English DT Article ID TRANSFORM MASS-SPECTROMETRY; TRANSLATIONAL ENERGY-DEPENDENCE; COLLISION-INDUCED DISSOCIATION; FE+-BENZYNE; ACTIVATION; ALKANES; ALKENES; COMPLEXES; TI+ AB The gas-phase chemistry of Sc+-benzyne with a wide variety of simple molecules is reported. The reactant ion, ScC6H4+, was prepared from the dehydrogenation of benzene by Sc+. ScC6H4+ undergoes an unusual hydrogenation reaction with H2 and D2, as well as H/D exchange with the latter. Its reactions with a number of oxygen-containing species, XO, give ScO+. The ability to form stable C6H4X neutral products from benzyne is a key factor in making this reaction exothermic. With the exception of methane, ScC6H4+ reacts with all of the alkanes and alkenes studied to form a wide variety of product ions. A selected number of ions were subjected to more detailed structural study. Sc+-styrene is formed from the reaction with ethane and propane. Sc+-indane is also formed from the reaction with propane. The product ion ScC8H10+ from n-butane is Sc+-ethylbenzene. A prominent ion, ScC9H7+, is formed from butadiene. Its frequent occurrence, unusual formulation, and resistance to fragmentation all indicate a high stability, with its structure most likely being that of the indenylscandium cation. D-degrees-(Sc+-benzyne) = 88 +/- 5 kcal/mol was determined indirectly from the photodissociation threshold for loss of H2 from Sc+-benzene and from the observation that Sc+ exothermically dehydrogenates benzene to form Sc+-benzyne. Theoretical study indicates that the gas-phase structure is analogous to that of solid-phase mononuclear transition-metal-benzyne complexes observed crystallographically in which the metal center is coplanar with the benzyne ring and inserted symmetrically into the C-C triple bond forming a benzometallacyclopropene. The theoretical bond energy for the planar singlet D-degrees-(Sc+-C6H4) = 94 kcal/mol is in good agreement with experiment. C1 PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 32 TC 25 Z9 25 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD OCT 2 PY 1991 VL 30 IS 20 BP 3822 EP 3829 DI 10.1021/ic00020a010 PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA GH746 UT WOS:A1991GH74600010 ER PT J AU HATHER, BM TESCH, PA BUCHANAN, P DUDLEY, GA AF HATHER, BM TESCH, PA BUCHANAN, P DUDLEY, GA TI INFLUENCE OF ECCENTRIC ACTIONS ON SKELETAL-MUSCLE ADAPTATIONS TO RESISTANCE TRAINING SO ACTA PHYSIOLOGICA SCANDINAVICA LA English DT Article DE CAPILLARY SUPPLY; CONCENTRIC AND ECCENTRIC MUSCLE ACTIONS; DETRAINING; FIBER TYPES AND SIZE; HYPERTROPHY; STRENGTH TRAINING ID ENZYME-ACTIVITIES; EXERCISE; FIBERS; EXCRETION; WEIGHT; FORCE; MEN AB Three different training regimens were performed to study the influence of eccentric muscle actions on skeletal muscle adaptive responses to heavy resistance exercise. Middle-aged males performed the leg press and leg extension exercises two days each week. The resistance was selected to induce failure within six to twelve repetitions of each set. Group CON/ECC (n = 8) performed coupled concentric and eccentric actions while group CON (n = 8) used concentric actions only. They did four or five sets of each exercise. Group CON/CON (n = 10) performed twice as many sets with only concentric actions. Eight subjects did not train and served as controls. Tissue samples were obtained from m. vastus lateralis using the biopsy technique before and after 19 weeks of training, and after four weeks of detraining. Histochemical analyses were performed to assess fibre type composition, fibre area and capillarization. Training increased (P < 0.05) Type IIA and decreased (P < 0.05) Type IIB fibre percentage. Only group CON/ECC increased Type I area (14%, P < 0.05). Type II area increased (P < 0.05) 32 and 27%, respectively, in groups CON/ECC and CON/CON, but not in group CON. Mean fibre area increased (P < 0.05) 25 and 20% in groups CON/ECC and CON/CON, respectively. Capillaries per fibre increased (P < 0.05) equally for Type I and Type II fibres. Capillaries per fibre area for both fibre types, however, increased (P < 0.05) only in groups CON and CON/CON. The changes in fibre type composition and capillary frequency were manifest after detraining. At this time only group CON/ECC showed mean fibre hypertrophy, while capillary density was elevated in groups CON/CON and CON. This study suggests that optimal muscle hypertrophy in response to resistance exercise is not attained unless eccentric muscle actions are performed. The data also show that heavy resistance exercise may produce muscle fibre transformation and capillary neoformation. C1 NASA,BIOMED OPERAT & RES OFF,MAIL CODE MD-M,KENNEDY SPACE CTR,FL 32899. KAROLINSKA INST,DEPT PHYSIOL,ENVIRONM PHYSIOL LAB,S-10401 STOCKHOLM 60,SWEDEN. BIONET CORP,BIOMED & ENVIRONM LABS,KENNEDY SPACE CTR,FL. NR 40 TC 209 Z9 212 U1 4 U2 26 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0001-6772 J9 ACTA PHYSIOL SCAND JI Acta Physiol. Scand. PD OCT PY 1991 VL 143 IS 2 BP 177 EP 185 DI 10.1111/j.1748-1716.1991.tb09219.x PG 9 WC Physiology SC Physiology GA GH961 UT WOS:A1991GH96100005 PM 1835816 ER PT J AU AHMED, S BOND, R MCKANNAN, EC AF AHMED, S BOND, R MCKANNAN, EC TI SOLIDIFICATION PROCESSING SUPERALLOYS IN AN ELECTRIC-FIELD SO ADVANCED MATERIALS & PROCESSES LA English DT Article C1 IIT,RES INST,HUNTSVILLE,AL. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP AHMED, S (reprint author), YOUNGSTOWN STATE UNIV,DEPT MAT ENGN & MAT SCI,YOUNGSTOWN,OH 44555, USA. NR 0 TC 9 Z9 12 U1 3 U2 4 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 OCT PY 1991 VL 140 IS 4 BP 30 EP & PG 0 WC Materials Science, Multidisciplinary SC Materials Science GA GJ869 UT WOS:A1991GJ86900004 ER PT J AU HEINDEL, TA MURPHY, TB RASMUSSEN, AN MCFARLAND, RZ MONTGOMERY, RE POHLE, GE AF HEINDEL, TA MURPHY, TB RASMUSSEN, AN MCFARLAND, RZ MONTGOMERY, RE POHLE, GE TI SHELLS FOR MISSION CONTROL SO AEROSPACE AMERICA LA English DT Article RP HEINDEL, TA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, 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 OCT PY 1991 VL 29 IS 10 BP 8 EP 11 PG 4 WC Engineering, Aerospace SC Engineering GA GJ521 UT WOS:A1991GJ52100002 ER PT J AU HEARD, AE AF HEARD, AE TI COUNTDOWN AT KENNEDY SO AEROSPACE AMERICA LA English DT Article RP HEARD, AE (reprint author), NASA,ADV SOFTWARE PROGRAM,KENNEDY SPACE CTR,FL 32815, 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 OCT PY 1991 VL 29 IS 10 BP 11 EP 14 PG 4 WC Engineering, Aerospace SC Engineering GA GJ521 UT WOS:A1991GJ52100003 ER PT J AU ATKINSON, DJ AF ATKINSON, DJ TI AUTOMATING SPACE EXPLORATION SO AEROSPACE AMERICA LA English DT Article RP ATKINSON, DJ (reprint author), CALTECH,JET PROP LAB,ADV INFORMAT SYST,PASADENA,CA 91109, 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 OCT PY 1991 VL 29 IS 10 BP 14 EP 18 PG 5 WC Engineering, Aerospace SC Engineering GA GJ521 UT WOS:A1991GJ52100004 ER PT J AU LEA, RN JANI, Y AF LEA, RN JANI, Y TI FUZZY-LOGIC CAPTURES HUMAN SKILLS SO AEROSPACE AMERICA LA English DT Article RP LEA, RN (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, 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 OCT PY 1991 VL 29 IS 10 BP 25 EP 27 PG 3 WC Engineering, Aerospace SC Engineering GA GJ521 UT WOS:A1991GJ52100007 ER PT J AU ALBERTSON, CW ASH, RL AF ALBERTSON, CW ASH, RL TI COMPRESSIBLE EQUILIBRIUM TURBULENT BOUNDARY-LAYERS AT NONADIABATIC WALL CONDITIONS SO AIAA JOURNAL LA English DT Article AB Experimental data have been obtained to define test conditions necessary for a compressible, naturally developing, equilibrium turbulent boundary layer. The model consisted of a flat plate that was tested in the NASA Langley Research Center 8-ft high temperature tunnel. For the present study, the nominal boundary-layer edge Mach numbers were 5.0 and 6.2. The local Reynolds number based on boundary-layer edge conditions and plate length ranged from 8 x 10(6) to 39 x 10(6). The nominal ratio of adiabatic wall to actual wall temperature was 5.4, due to both the high total temperature of 3300-degrees-R and the heat-sink characteristics of the model. This temperature ratio is considerably higher than that obtained in previous compressible boundary-layer studies and simulates hypersonic flight under highly cooled wall conditions, which are anticipated for hypersonic cruise vehicles. The data indicate that a momentum thickness Reynolds number of at least 4000 is required for an equilibrium turbulent boundary layer, which is in approximate agreement with incompressible studies. This criterion was determined by comparing the transformed wake strength of the boundary layer with the incompressible data of Coles. Also, several shape factors were examined and found to support the trend shown by the wake strength. C1 OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23508. RP ALBERTSON, CW (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT MECH,AEROTHERMAL LOADS BRANCH,HAMPTON,VA 23665, USA. NR 25 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD OCT PY 1991 VL 29 IS 10 BP 1573 EP 1580 DI 10.2514/3.61522 PG 8 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600004 ER PT J AU BANDYOPADHYAY, PR STEAD, DJ ASH, RL AF BANDYOPADHYAY, PR STEAD, DJ ASH, RL TI ORGANIZED NATURE OF A TURBULENT TRAILING VORTEX SO AIAA JOURNAL LA English DT Article ID EQUILIBRIUM PUFF; STABILITY; FLOW; PIPE AB Experiments have been carried out into the turbulence structure of a low-Reynolds-number (15 x 10(3) < Re-GAMMA < 25 x 10(3), based on the maximum azimuthal velocity and core diameter) trailing vortex produced at the juncture of a flow aligned cylinder and a pair of oppositely loaded airfoils. Five different types of screens are placed ahead of the vortex generator. Components of the mean velocity, Reynolds stress flux, and quasiperiodic large-scale wavelengths have been measured. The turbulence structure varies with Rossby number. The vortex core is not a benign solid body of rotation. It has intermittent patches of turbulent and laminarescent fluid. The shear-stress-rich low-momentum core fluid intermittently ejects outwards in the direction of vortex rotation. C1 OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23508. RP BANDYOPADHYAY, PR (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 170,HAMPTON,VA 23665, USA. NR 18 TC 40 Z9 40 U1 1 U2 5 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 OCT PY 1991 VL 29 IS 10 BP 1627 EP 1633 DI 10.2514/3.10784 PG 7 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600011 ER PT J AU KIM, KS LEE, Y ALVI, FS SETTLES, GS HORSTMAN, CC AF KIM, KS LEE, Y ALVI, FS SETTLES, GS HORSTMAN, CC TI SKIN-FRICTION MEASUREMENTS AND COMPUTATIONAL COMPARISON OF SWEPT SHOCK BOUNDARY-LAYER INTERACTIONS SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 28TH MEETING ON AEROSPACE SCIENCES CY JAN 08-11, 1990 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT ID LASER INTERFEROMETER; SHARP-FIN AB A joint experimental and computational study of skin friction in weak-to-strong swept shock wave/turbulent boundary-layer interactions has been carried out. A planar shock wave is generated by a sharp fin at angles of attack alpha = 10 and 16 deg at M infinity = 3 and 16 and 20 deg at M infinity = 4. Measurements are made using the laser interferometer skin friction (LISF) meter, which optically detects the rate of thinning of an oil film applied to the test surface. The results show a systematic rise in the peak c(f) at the rear part of the interaction, where the separated flow attaches. For the strongest case studied, this peak is an order of magnitude higher than the incoming free-stream c(f) level. Navier-Stokes computations of these flows agree well with the data for moderate interaction strengths, but systematically underpredict the data with increasing interaction strength. Algebraic eddy-viscosity turbulence models produce the best prediction of the measured c(f) distributions but still fail for the strongest cases studied. However, in predicting surface streamline angles, a k-epsilon turbulence model with integration to the wall produced the best results. C1 NASA,AMES RES CTR,DEPT MECH ENGN,GAS DYNAM LAB,MOFFETT FIELD,CA 94035. RP KIM, KS (reprint author), PENN STATE UNIV,DEPT MECH ENGN,GAS DYNAM LAB,303 ME BLDG,UNIVERSITY PK,PA 16802, USA. NR 26 TC 19 Z9 20 U1 0 U2 2 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 OCT PY 1991 VL 29 IS 10 BP 1643 EP 1650 DI 10.2514/3.10786 PG 8 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600013 ER PT J AU HUNG, CM AF HUNG, CM TI COMPUTATION OF NAVIER-STOKES EQUATIONS FOR 3-DIMENSIONAL FLOW SEPARATION SO AIAA JOURNAL LA English DT Article ID BOUNDARY-LAYER INTERACTION; INDUCED SHOCK-WAVE; SIMULATION AB Supersonic flows over a sharp and a flat-faced blunt fin mounted on a flat plate are simulated numerically. Several basic issues involved in the resultant three-dimensional steady flow separation are studied. Using the same number of grid points, different grid spacings are employed to investigate the effects of grid resolution on the origin of the line of separation. Various shock strengths are used to study the separation of boundary layer and to establish the existence or absence of secondary separation. The length of separation ahead of the flat-faced blunt fin, bifurcation of a horseshoe vortex, and the accessibility of a closed-type separation are investigated. The usual interpretation of the flowfield from previous studies and new interpretations arising from the present simulation are discussed. RP HUNG, CM (reprint author), NASA,AMES RES CTR,COMPUTAT FLUID DYNAM BRANCH,MAIL STOP 202A-1,MOFFETT FIELD,CA 94035, USA. NR 27 TC 0 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD OCT PY 1991 VL 29 IS 10 BP 1659 EP 1667 DI 10.2514/3.10788 PG 9 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600015 ER PT J AU OBAYASHI, S GURUSWAMY, GP GOORJIAN, PM AF OBAYASHI, S GURUSWAMY, GP GOORJIAN, PM TI STREAMWISE UPWIND ALGORITHM FOR COMPUTING UNSTEADY TRANSONIC-FLOWS PAST OSCILLATING WINGS SO AIAA JOURNAL LA English DT Article ID FINITE-DIFFERENCE; EULER EQUATIONS AB A streamwise upwind algorithm has been extended to compute unsteady flows with a moving grid system and applied to compute flows over oscillating wings at transonic Mach numbers. Comparisons have been made between results obtained from this upwind algorithm, using both temporally nonconservative- and conservative-implicit methods, with the results obtained from a central-difference method, and also with experimental data. The efficiency and practicality of the temporally nonconservative implicit solver are illustrated. Results to show the robustness and accuracy of the upwind method for unsteady computations compared to the central-difference method are presented. RP OBAYASHI, S (reprint author), NASA,AMES RES CTR,INST MCAT,MOFFETT FIELD,CA 94035, USA. NR 31 TC 13 Z9 14 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 OCT PY 1991 VL 29 IS 10 BP 1668 EP 1677 DI 10.2514/3.10789 PG 10 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600016 ER PT J AU CREWS, JH SHIVAKUMAR, KN RAJU, IS AF CREWS, JH SHIVAKUMAR, KN RAJU, IS TI STRAIN-ENERGY RELEASE RATE DISTRIBUTIONS FOR DOUBLE CANTILEVER BEAM SPECIMENS SO AIAA JOURNAL LA English DT Article ID BODIES AB A three-dimensional finite element analysis was conducted for a double cantilever beam (DCB) specimen under mode I (opening) loading. The specimen had dimensions typical of 24-ply composite DCB test specimens. Strain energy release rate G distributions were calculated along a straight delamination starter for several different DCB materials. An isotropic DCB specimen was found to have a G distribution that varied significantly along its delamination front. This variation was explained as the combined result of the well-known boundary-layer effect and an effect due to anticlastic curvature of the bent specimen arms. The anticlastic curvature effects were discussed using the parameter nu(xy) E(yy)/E(xx), where nu(xy) is Poisson's ratio, and E(xx) and E(yy) are longitudinal and transverse (width-direction) moduli, respectively. This parameter was shown to be a good predictor of the G variability along the delamination front. A 0-deg graphite/epoxy specimen had a nearly uniform G distribution with a drop only near its edge, due to the boundary-layer effect. In contrast, a (+/- 45 deg) graphite/epoxy case had a pronounced G variation across the specimen width. A bonded aluminum DCB specimen had a G variation that was nearly identical to a comparable specimen without a bondline. RP CREWS, JH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 17 TC 24 Z9 24 U1 0 U2 5 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 OCT PY 1991 VL 29 IS 10 BP 1686 EP 1691 DI 10.2514/3.10791 PG 6 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600018 ER PT J AU SHIH, TIP CHYU, WJ AF SHIH, TIP CHYU, WJ TI APPROXIMATE FACTORIZATION WITH SOURCE TERMS SO AIAA JOURNAL LA English DT Note ID EQUATIONS; SCHEME C1 NASA,AMES RES CTR,APPL AERODYNAM BRANCH,MOFFETT FIELD,CA 94035. RP SHIH, TIP (reprint author), CARNEGIE MELLON UNIV,DEPT MECH ENGN,PITTSBURGH,PA 15213, USA. NR 9 TC 11 Z9 11 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 OCT PY 1991 VL 29 IS 10 BP 1759 EP 1760 DI 10.2514/3.10800 PG 2 WC Engineering, Aerospace SC Engineering GA GH486 UT WOS:A1991GH48600027 ER PT J AU RESSLER, ME SHURE, M AF RESSLER, ME SHURE, M TI 2 PROTOSTAR CANDIDATES IN THE BRIGHT-RIMMED DARK CLOUD LDN-1206 SO ASTRONOMICAL JOURNAL LA English DT Article ID IRAS SOURCES; YOUNG STARS; REGIONS; OBJECTS; CATALOG; NEBULA; CORES AB We report the discovery of several near-infrared objects associated with two IRAS point sources in the LDN 1206 region. IRAS 22272 + 6358A is probably a "protostar" which is seen only in scattered light at near-infrared wavelengths because of heavy obscuration by an almost edge-on circumstellar disk. In contrast, IRAS 22272 + 6358B is directly visible at these wavelengths and is perhaps an object which lies between protostars and T Tauri stars in its evolution. Both direct and polarimetric K band images of the region are presented, as well as spectral energy distributions constructed from our J, H, K, L, L', and M data and published far-infrared and millimeter data. C1 UNIV HAWAII,NASA,INFRARED TELESCOPE FACIL,HONOLULU,HI 96822. RP RESSLER, ME (reprint author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA. NR 25 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 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 1991 VL 102 IS 4 BP 1398 EP 1404 DI 10.1086/115965 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GG675 UT WOS:A1991GG67500016 ER PT J AU DUNHAM, EW MCDONALD, SW ELLIOT, JL AF DUNHAM, EW MCDONALD, SW ELLIOT, JL TI PLUTO CHARON STELLAR OCCULTATION CANDIDATES - 1990-1995 SO ASTRONOMICAL JOURNAL LA English DT Article ID CCD; NOISE AB We have carried out a search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5-about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occulations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in our list would yield an S/N of about 20 for a 1 s integration when observed with a CCD detector on an 8 m telescope under a dark sky. Our astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occulations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, we expect about 32 of these events to be observable somewhere on Earth. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented. C1 MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP DUNHAM, EW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 19 TC 21 Z9 21 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 OCT PY 1991 VL 102 IS 4 BP 1464 EP 1484 DI 10.1086/115973 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GG675 UT WOS:A1991GG67500024 ER PT J AU OSTRO, SJ CAMPBELL, DB CHANDLER, JF SHAPIRO, II HINE, AA VELEZ, R JURGENS, RF ROSEMA, KD WINKLER, R YEOMANS, DK AF OSTRO, SJ CAMPBELL, DB CHANDLER, JF SHAPIRO, II HINE, AA VELEZ, R JURGENS, RF ROSEMA, KD WINKLER, R YEOMANS, DK TI ASTEROID RADAR ASTROMETRY SO ASTRONOMICAL JOURNAL LA English DT Article ID 433-EROS; IMAGES AB We report all useful measurements of time delay and Doppler frequency for asteroid radar echoes obtained at Arecibo and Goldstone during 1980-1990. New radar astrometry is presented for 23 near-Earth asteroids and three mainbelt asteroids. These measurements, which are orthogonal to optical, angular-position measurements, and typically have a fractional precision between 10(-5) and 10(-8), permit significant improvement in estimates of orbits and hence in the accuracy of prediction ephemerides. We also report estimates of radar cross section and circular polarization ratio for all asteroids observed astrometrically during 1980-1990. C1 CORNELL UNIV, NATL ASTRON & IONOSPHERE CTR, ITHACA, NY 14853 USA. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. NATL ASTRON & IONOSPHERE CTR, ARECIBO, PR 00613 USA. RP OSTRO, SJ (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 34 TC 45 Z9 46 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 1991 VL 102 IS 4 BP 1490 EP 1502 DI 10.1086/115975 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GG675 UT WOS:A1991GG67500026 ER EF