FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Lawrence, JK Ruzmaikin, AA AF Lawrence, JK Ruzmaikin, AA TI Transient solar influence on terrestrial temperature fluctuations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STOCHASTIC RESONANCE; CLIMATE; CYCLE; QBO AB We argue that the 11-year periodic solar cycle input assisted by intrinsic climatic noise can produce transient correlations between activity on the Sun and the Earth's temperature. The argument is based on wavelet analysis of simultaneous, 140 year time series of terrestrial global temperature and solar activity. It is supported by a simple model utilizing the concept of "stochastic resonance," a unique effect of amplification of a weak, periodic signal by a noisy, nonlinear system. C1 Calif State Univ Northridge, Dept Phys & Astron, Northridge, CA 91330 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lawrence, JK (reprint author), Calif State Univ Northridge, Dept Phys & Astron, 18111 Nordhoff St, Northridge, CA 91330 USA. NR 21 TC 10 Z9 11 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 1998 VL 25 IS 2 BP 159 EP 162 DI 10.1029/97GL03568 PG 4 WC Geosciences, Multidisciplinary SC Geology GA YT257 UT WOS:000071581600007 ER PT J AU Wang, L Koblinsky, C Howden, S Beckley, B AF Wang, L Koblinsky, C Howden, S Beckley, B TI Large-scale Rossby wave in the mid-latitude South Pacific from altimetry data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID KUROSHIO EXTENSION; PROPAGATION; VARIABILITY AB We present observations of large-scale Rossby wave propagation in the mid-latitude South Pacific (25 degrees S) from analyzing 4 years of TOPEX/POSEIDON altimetry data. Using wavelet transform we separate phase propagation from amplitude modulation. The dominant Rossby wave has a wavelength of about 40 degrees with a period close to 2 years (phase speed similar to 6.4 cm/s). Its amplitude modulates both interannually and intra-annually. In addition, we also found a shorter-scale Rossby wave with a wavelength of about 16 degrees and a period close to 9 months. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wang, L (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 12 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 1998 VL 25 IS 2 BP 179 EP 182 DI 10.1029/97GL03567 PG 4 WC Geosciences, Multidisciplinary SC Geology GA YT257 UT WOS:000071581600012 ER PT J AU Monks, PS Stief, LJ Krauss, M Kuo, SD Zhang, Z Klemm, RB AF Monks, PS Stief, LJ Krauss, M Kuo, SD Zhang, Z Klemm, RB TI Comment on "A study of Hel photoelectron spectroscopy on the electronic structure of the nitrate free radical NO3" SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Stief, LJ (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Monks, Paul/H-6468-2016 OI Monks, Paul/0000-0001-9984-4390 NR 2 TC 3 Z9 3 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 15 PY 1998 VL 108 IS 3 BP 1292 EP 1292 DI 10.1063/1.475492 PG 1 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YR359 UT WOS:000071487500055 ER PT J AU Arrigo, KR Weiss, AM Smith, WO AF Arrigo, KR Weiss, AM Smith, WO TI Physical forcing of phytoplankton dynamics in the southwestern Ross Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID ICE EDGE; MCMURDO SOUND; PRIMARY PRODUCTIVITY; BLOOM DYNAMICS; SOUTHERN-OCEAN; ANTARCTICA; COMMUNITIES; PATTERNS AB Coastal zone color scanner (CZCS) imagery of phytoplankton pigments and passive microwave imagery of sea ice distributions in the southwestern Ross Sea are presented for three different seasons (1978-1989, 1979-1980, and 1981-1982) and were analyzed in conjunction with meteorological data obtained from a series of automatic weather stations (AWS). Dynamics of the phytoplankton bloom in Terra Nova Bay differed from those in the Boss Sea owing to spatial differences in katabatic wind fields which determine when the surface waters stratify. Interannual variation in the timing of formation of the Ross Sea polynya appears to be controlled by winter temperatures, which determine sea ice thickness and integrity, rather than variability or intensity in wind stress. Together, CZCS, AWS, and passive microwave data suggest that when the Ross Sea polynya forms early, stronger and more frequent katabatic winds result in increased advective losses of phytoplankton in surface waters and a delay in the phytoplankton bloom. If polynya formation is delayed until after the winds diminish in frequency, the phytoplankton bloom will develop earlier. The observation that diatoms dominate both the marginal ice zone and Terra Nova Bay, which are hydrographically similar, while Phaeocystis antarctica is found in unstable waters north of the Ross Ice Shelf,suggests that stratification plays an important role in determining species composition in the Ross Sea. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. Univ Tennessee, Dept Ecol & Evolut Biol, Knoxville, TN 37996 USA. RP Arrigo, KR (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971-0, Greenbelt, MD 20771 USA. NR 28 TC 111 Z9 111 U1 2 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JAN 15 PY 1998 VL 103 IS C1 BP 1007 EP 1021 DI 10.1029/97JC02326 PG 15 WC Oceanography SC Oceanography GA YQ713 UT WOS:000071415800001 ER PT J AU Randel, WJ Wu, F Russell, JM Roche, A Waters, JW AF Randel, WJ Wu, F Russell, JM Roche, A Waters, JW TI Seasonal cycles and QBO variations in stratospheric CH4 and H2O observed in UARS HALOE data SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; WATER-VAPOR BUDGET; MIDDLE ATMOSPHERE; POLAR VORTEX; SEMIANNUAL OSCILLATION; TRACER TRANSPORT; OCCULTATION EXPERIMENT; NUMERICAL-MODEL; SURF ZONE; 10 MB AB Measurements of stratospheric methane (CH4) and water vapor (H2O) are used to investigate seasonal and interannual variability in stratospheric transport. Data are from the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) spanning 1991-97. Profile measurements are binned according to analyzed potential vorticity fields (equivalent latitude mapping), and seasonal cycles are fit using harmonic regression analysis. Methane data from the UARS Cryogenic Limb Array Etalon Spectrometer and water vapor from the Microwave Limb Sounder are also used to fill in winter polar latitudes (where HALOE measurements are unavailable), yielding complete global seasonal cycles. These data reveal well-known seasonal variations with novel detail, including 1) the presence of enhanced latitudinal gradients (mixing barriers) in the subtropics and across the polar vortices, 2) strong descent inside the polar vortices during winter and spring, and 3) vigorous seasonality in the tropical upper stratosphere, related to seasonal upwelling and the semiannual oscillation. The observed variations are in agreement with aspects of the mean meridional circulation derived from stratospheric meteorological analyses. Interannual variations are also investigated, and a majority of the variance is found to be coherent with the equatorial quasibiennial oscillation (QBO). Strong QBO influence is found in the tropical upper stratosphere: the double-peaked "rabbit ears" structure occurs primarily during QBO westerlies. The PBO also modulates the latitudinal position of the tropical "reservoir" in the middle stratosphere. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Lackheed Martin Adv Technol Ctr, Palo Alto, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Randel, WJ (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Pob 3000, Boulder, CO 80307 USA. EM randel@ucar.edu RI Randel, William/K-3267-2016 OI Randel, William/0000-0002-5999-7162 NR 87 TC 211 Z9 217 U1 2 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JAN 15 PY 1998 VL 55 IS 2 BP 163 EP 185 DI 10.1175/1520-0469(1998)055<0163:SCAQVI>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YT205 UT WOS:000071576300003 ER PT J AU Liu, HS Chao, BF AF Liu, HS Chao, BF TI Wavelet spectral analysis of the earth's orbital variations and paleoclimatic cycles SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ICE-AGE CYCLE; STOCHASTIC RESONANCE; SENSITIVITY EXPERIMENTS; GLACIATION CYCLES; DEVILS-HOLE; CLIMATE; MECHANISM; RECORDS; CALCITE; SIGNAL AB The wavelet time-frequency spectral analysis is applied to geological records that are proxies of paleoclimatic variations: delta(18)O in sedimentary cores, atmospheric CO2 concentration, and a loess magnetic susceptibility stratigraphy within the past million years. These spectra are compared with those for the astronomically predicted variations of the earth's orbital eccentricity, obliquity, precession, and their resultant variations of the incoming insolation. The latter has been known to be unable to explain the characteristics of the observed 100-kyr paleoclimatic cycles. Based on similarities between the wavelet spectra of the orbital variations and paleoclimatic cycles, the authors introduce a signal-noise resonance theory to understand the dynamics of climate response to the orbital forcing. It is shown that the observed 100-kyr cycles are mainly caused by the period variation in the obliquity, which amplifies the small orbital forcing. But the observed flickers within these cycles are induced by the amplitude variation of obliquity and precession, which are two major components of the Milankovitch insolation deviations. C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Liu, HS (reprint author), NASA, Goddard Space Flight Ctr, Geodynam Branch, Code 921, Greenbelt, MD 20771 USA. EM hanshou@denali.gsfc.nasa.gov RI Chao, Benjamin Fong/N-6156-2013 NR 35 TC 18 Z9 20 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JAN 15 PY 1998 VL 55 IS 2 BP 227 EP 236 DI 10.1175/1520-0469(1998)055<0227:WSAOTE>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YT205 UT WOS:000071576300006 ER PT J AU Hecht, MH AF Hecht, MH TI Reply to "Comment on 'Role of photocurrent in low-temperature photoemission studies of Schottky-barrier formation'" SO PHYSICAL REVIEW B LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Hecht, MH (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1998 VL 57 IS 4 BP 2630 EP 2631 DI 10.1103/PhysRevB.57.2630 PG 2 WC Physics, Condensed Matter SC Physics GA YV536 UT WOS:000071834900092 ER PT J AU Dvali, G Riotto, A AF Dvali, G Riotto, A TI Minimalism in inflation model building SO PHYSICS LETTERS B LA English DT Article ID D-TERMS; HYBRID INFLATION; SUPERSYMMETRY; SUPERGRAVITY; SUPERSTRINGS; CONSTRAINTS AB In this paper we demand that a successful inflationary scenario should follow from a model entirely motivated by particle physics considerations. We show that such a connection is indeed possible within the framework of concrete supersymmetric Grand Unified Theories where the doublet-triplet splitting problem is naturally solved. The Fayet-Iliopoulos D-term of a gauge U(1)(xi) symmetry, which plays a crucial role in the solution of the doublet-triplet splitting problem, simultaneously provides a built-in inflationary slope protected from dangerous supergravity corrections. (C) 1998 Published by Elsevier Science B.V. C1 CERN, Div Theory, CH-1211 Geneva, Switzerland. NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Dvali, G (reprint author), CERN, Div Theory, CH-1211 Geneva, Switzerland. NR 29 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JAN 15 PY 1998 VL 417 IS 1-2 BP 20 EP 26 DI 10.1016/S0370-2693(97)01357-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA YY923 UT WOS:000072201500004 ER PT J AU Catling, DC AF Catling, DC TI High-sensitivity silicon capacitive sensors for measuring medium-vacuum gas pressures SO SENSORS AND ACTUATORS A-PHYSICAL LA English DT Article DE pressure sensors; capacitive; vacuum measurement ID TRANSDUCER AB The design, construction, and preliminary testing of an experimental capacitive silicon pressure sensor are described. The prototype sensor is designed as a robust, precision barometer suitable for measurements on the planet Mars where the mean atmospheric pressure is similar to 6 mbar (600 Pa). Most commercially available silicon pressure sensors tend to operate over pressure ranges greater than or equal to 1 bar, or measure gauge pressure, but this sensor is specifically constructed to measure absolute pressure of 0-10 mbar with a very high sensitivity similar to 1 pF mbar (-1). The transductional mechanism is the deflection of a silicon diaphragm under applied pressure across a sealed vacuum cavity. Under storage conditions of 1 bar, the diaphragm displacement is mechanically constrained by an underlying stopping surface. Finite-element analysis shows that typical structures are extremely resistant to overpressure: fracture occurs at many tens of bar. The device is fabricated using a silicon fusion-bonded vacuum cavity which provides for relative insensitivity to temperature changes. (C) 1998 Elsevier Science S.A. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Catling, DC (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM catling@humbabe.arc.nasa.gov RI Catling, David/D-2082-2009; OI Catling, David/0000-0001-5646-120X NR 30 TC 24 Z9 25 U1 3 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-4247 J9 SENSOR ACTUAT A-PHYS JI Sens. Actuator A-Phys. PD JAN 15 PY 1998 VL 64 IS 2 BP 157 EP 164 DI 10.1016/S0924-4247(98)80009-5 PG 8 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA YN492 UT WOS:000071174000006 ER PT J AU Halicioglu, T AF Halicioglu, T TI Stress calculations for carbon nanotubes SO THIN SOLID FILMS LA English DT Letter DE carbon nanotubes; graphitic tubules; atomic AB Atomic stresses were calculated for carbon nanotubes under stra n conditions. Graphitic tubules with radii ranging from approximately 2 to 11 Angstrom and two different tubule structures with varying atomic orientations were included in the calculations. Elongations and contractions were applied in the axial direction and atomic stress values were calculated fur infinitely long tubules. The calculations were carried out using Brenner's function which was developed for carbon species. Results indicate that the stress is tensile in the radial direction while it is compressive in the tangential direction. Variations in-stress values in the direction of the cylindrical axis were investigated as a function of applied strain. Furthermore, using thr: stress-strain curve (calculated based on atomic considerations), the values of Young's modulus and Poissons ratio for nanotubules were also estimated. (C) 1998 Elsevier Science S.A. C1 NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. RP Halicioglu, T (reprint author), Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA. NR 12 TC 58 Z9 61 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JAN 14 PY 1998 VL 312 IS 1-2 BP 11 EP 14 DI 10.1016/S0040-6090(97)00369-6 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA ZN334 UT WOS:000073635500004 ER PT J AU Canuto, VM Dubovikov, MS AF Canuto, VM Dubovikov, MS TI Two scaling regimes for rotating Rayleigh-Benard convection SO PHYSICAL REVIEW LETTERS LA English DT Article ID DYNAMICAL MODEL; TURBULENCE; STATES AB Using a turbulence model, we derive two scaling regimes for rapidly rotating Rayleigh-Benard turbulent convection. For Ra-* < Ra < Ra-**, where Ra-* and Ra-** are functions of Omega, the Nusselt number Nu is a function only of the scaling variable Ra/Ra-*; this corresponds to the first regime. For Ra > Ra-**, Nu is almost unaffected by rotation and satisfies the nonrotating scaling law Nu similar to Ra-gamma, gamma similar to 1/3. The two scaling laws are confirmed by existing data. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 19 TC 9 Z9 9 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 12 PY 1998 VL 80 IS 2 BP 281 EP 284 DI 10.1103/PhysRevLett.80.281 PG 4 WC Physics, Multidisciplinary SC Physics GA YQ975 UT WOS:000071444000019 ER PT J AU Stanford, SA Eisenhardt, PR Dickson, M AF Stanford, SA Eisenhardt, PR Dickson, M TI The evolution of early-type galaxies in distant clusters SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, general; galaxies, elliptical and lenticular, cD; galaxies, evolution; galaxies, photometry ID ELLIPTICAL GALAXIES; STAR-FORMATION; STELLAR POPULATIONS; MAGNITUDE RELATION; DISK GALAXIES; COLORS; PHOTOMETRY; MODEL; COMA; HST AB We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z = 0.9. The galaxy sample is selected on the basis of morphologies determined from Hubble Space Telescope (HST) WFPC2 images and is photometrically defined in the K band in order to minimize redshift-dependent selection biases. Using new ground-based photometry in five optical and infrared bands for each cluster, we examine the evolution of the color-magnitude relation for early-type cluster galaxies, considering its slope, intercept, and color scatter around the mean relation. New multiwavelength photometry of galaxies in the Coma Cluster is used to provide a baseline sample at z approximate to 0 with which to compare the distant clusters. The optical-IR colors of the early-type cluster galaxies become bluer with increasing redshift in a manner consistent with the passive evolution of an old stellar population formed at an early cosmic epoch. The degree of color evolution is similar for clusters at similar redshift and does not depend strongly on the optical richness or X-ray luminosity of the cluster, which suggests that the history of early-type galaxies is relatively insensitive to environment, at least above a certain density threshold. The slope of the color-magnitude relationship shows no significant change out to z = 0.9, which provides evidence that it arises from a correlation between galaxy mass and metallicity, not age. Finally, the intrinsic scatter in the optical-IR colors of the galaxies is small and nearly constant with redshift, which indicates that the majority of giant, early-type galaxies in clusters share a common star formation history, with little perturbation due to uncorrelated episodes of later star formation. Taken together, our results are consistent with models in which most early-type galaxies in rich clusters are old, formed the majority of their stars at high redshift in a well-synchronized fashion, and evolved quiescently thereafter. We consider several possible effects that may be introduced by the choice of morphologically recognizable elliptical and SO galaxies in dense environments as a subject for study. In particular, the inclusion of SO galaxies, which might be undergoing morphological transformation in clusters as part of the Butcher-Oemler effect, may influence the results of our investigation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Johns Hopkins Univ, Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Dickson, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 72 TC 465 Z9 465 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 461 EP 479 DI 10.1086/305050 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200005 ER PT J AU Yi, SY Demarque, P Oemler, A AF Yi, SY Demarque, P Oemler, A TI On the origin of the ultraviolet upturn in elliptical galaxies. II. Test of the horizontal-branch hypothesis SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, elliptical and lenticular, cD; galaxies, evolution; galaxies, stellar content; ultraviolet, galaxies ID POPULATION SYNTHESIS; MASS-LOSS; STELLAR POPULATION; GLOBULAR-CLUSTERS; TELESCOPE OBSERVATIONS; STARS; EVOLUTION; METALLICITY; SPECTRA; MODELS AB Whether or not metal-rich HE stars are the dominant UV source in giant elliptical galaxies (GEs) is an important question in current astronomical research. We follow up our previous evolutionary population synthesis study with quantitative tests to answer this question affirmatively under the following three conditions: (1) Reimers's empirical mass-loss formula is proper, (2) the mass-loss efficiency parameter eta in metal-rich stars is somewhat larger than the value estimated from the metal-poor star studies, and (3) the true value of the helium-enrichment parameter (Delta Y/Delta Z) is positive. All three important empirical characteristics of the UV upturn (i.e., the fact that strong UV upturns are restricted to GEs, the positive UV upturn-metallicity correlation, and the narrow range of the T(eff) of the UV sources) are closely reproduced for reasonable ranges of input parameters. We discuss the major sources of uncertainties in the models, such as the production and role of hot horizontal-branch stars in GEs, and the importance of galactic nucleosynthesis. C1 Yale Univ, Dept Astron, New Haven, CT 06520 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. RP Yi, SY (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. EM yi@shemesh.gsfc.nasa.gov; demarque@astro.yale.edu NR 80 TC 56 Z9 57 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 480 EP + DI 10.1086/305078 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200006 ER PT J AU Freudenreich, HT AF Freudenreich, HT TI A COBE model of the galactic bar and disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffuse radiation; galaxies, photometry; Galaxy, fundamental parameters; Galaxy, structure; infrared, galaxies ID MILKY-WAY; H-I; GALAXY; BULGE; MORPHOLOGY; SHAPE; DYNAMICS; GAS AB A model of the bar and old stellar disk of the Galaxy has been derived from the survey of the Diffuse Infrared Background Experiment (DIRBE) of the Cosmic Background Explorer at wavelengths of 1.25, 2.2, 3.5, and 4.9 mu m. It agrees very well with the data, except in directions in which the near-infrared optical depth is high. Among the conclusions drawn from the model is that the Sun is located approximately 16.5 pc above the midpoint of the Galactic plane. The disk has an outer edge 4 kpc from the Sun and is warped like the H I layer. It has a central hole roughly the diameter of the inner edge of the 3 kpc molecular cloud ring, and within that hole lies a bright, strong, "early-type" bar, tilted approximately 14 degrees from the Sun-Galactic center line. The model has 47 free parameters. The model is discussed in detail, and contour plots and images of the residuals are presented. C1 NASA, Goddard Space Flight Ctr, Hughes STX, Greenbelt, MD 20771 USA. RP Freudenreich, HT (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX, Code 685-9, Greenbelt, MD 20771 USA. EM freudenreich@gsfc.nasa.gov NR 53 TC 216 Z9 218 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 495 EP 510 DI 10.1086/305065 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200007 ER PT J AU Cavallo, RM Sweigart, AV Bell, RA AF Cavallo, RM Sweigart, AV Bell, RA TI Proton-capture nucleosynthesis in globular cluster red giant stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE globular clusters, general; nuclear reactions, nucleosynthesis, abundances; stars, abundances; stars, interiors; stars, late-type; stars, Population II ID SODIUM-ABUNDANCE VARIATIONS; NITROGEN ABUNDANCES; OXYGEN ABUNDANCES; HALO GIANTS; CYANOGEN DISTRIBUTION; REACTION-RATES; ISOTOPIC ABUNDANCES; SUBGIANT STARS; OMEGA-CENTAURI; EVOLVED STARS AB Observational evidence suggests that many of the variations of the surface abundances of light- to intermediate-mass elements (A < 28) in globular cluster red giant branch (RGB) stars can be attributed to noncanonical mixing between the surface and the deep stellar interior during the RGB phase. As a first step to studying this mixing in more detail, we have combined a large nuclear reaction network with four detailed stellar evolutionary sequences of different metallicities in order to follow the production and destruction of the C, N, O, Ne, Na, Mg, and Al isotopes around the hydrogen-burning shell (H shell) of globular cluster RGB stars. The abundance distributions determined:by this method allow for the variation in the temperature and density around the H shell as well as for the dependence on both the stellar luminosity and cluster metallicity. Because our nuclear reaction network operates separately from the stellar evolution code, we are able to more readily explore the effects of the uncertainties in the reaction rates on the calculated abundances. We discuss implications of our results for mixing in the context of the observational data. Our results are qualitatively consistent with the observed C versus N, O versus N, Na versus O, and Al versus O anticorrelations and their variations with both luminosity and metallicity. We see evidence for variations in Na without requiring changes in O, independent of metallicity, as observed by Norris and Da Costa in 1995 and Briley and coworkers in 1997. Also, we derive (12)C/(13)C ratios near the observed equilibrium value of 4 for all sequences and predict the temperature-dependent (16)O/(17)O equilibrium ratio based on new data for the (17)O(p, alpha)(14)N reaction rate. Additionally, we discuss the Mg isotopic abundances in light of the recent observations by Shetrone of M13 and NGC 6752. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Cavallo, RM (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM rob@astro.umd.edu; sweigart@bach.gsfc.nasa.gov; roger@astro.umd.edu NR 86 TC 74 Z9 74 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 575 EP 595 DI 10.1086/305053 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200013 ER PT J AU Dayal, A Hoffmann, WF Bieging, JH Hora, JL Deutsch, LK Fazio, GC AF Dayal, A Hoffmann, WF Bieging, JH Hora, JL Deutsch, LK Fazio, GC TI Mid-infrared (8-21 micron) imaging of proto-planetary nebulae SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared, ISM, continuum; ISM, abundances; planetary nebulae, general ID SPECTRAL IRRADIANCE CALIBRATION; PREPLANETARY NEBULAE; EMISSION FEATURES; BIPOLAR NEBULAE; MU-M; DUST; STARS; EXTINCTION; EVOLUTION; ORIGIN AB We present mid-infrared (8-21 mu m) images of thermal dust emission from two proto-planetary nebulae (PPNs), IRAS 07134+1005 and IRAS 22272+5435, which show a strong 21 mu m emission feature. Both of the sources are well resolved and show evidence for axial symmetry. From our images, we calculate temperature and optical depth maps and estimate the abundance of the 11 mu m and 21 mu m feature carriers. In both sources, the dust temperatures range from similar to 160-200 K. The optical depths in IRAS 07134 are about a factor of 3 lower than those in IRAS 22272, but the emission is optically thin in both sources. Our analyses of the feature-to-continuum ratios suggests that 0.5%-5% of the carbon in these objects may be in the form of large PAH molecules. We construct optically thin, axially symmetric cylindrical shell models to simulate the observed mid-IR morphologies and spectra, and calculate nebular masses of 0.26 M. for IRAS 07134 and 0.42 M. for IRAS 22272. Although the mid-IR emission primarily comes from warm (T approximate to 190 K) dust, our models require a significant cooler dust (T approximate to 80 K) component to fit the observed mid-and far-IR spectral energy distributions. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Ctr Astrophys, Cambridge, MA 02138 USA. RP Dayal, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-900, Pasadena, CA 91109 USA. OI Hora, Joseph/0000-0002-5599-4650 NR 49 TC 47 Z9 47 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 603 EP 616 DI 10.1086/305051 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200015 ER PT J AU Schaefer, BE Palmer, D Dingus, BL Schneid, EJ Schoenfelder, V Ryan, J Winkler, C Hanlon, L Kippen, RM Connors, A AF Schaefer, BE Palmer, D Dingus, BL Schneid, EJ Schoenfelder, V Ryan, J Winkler, C Hanlon, L Kippen, RM Connors, A TI Gamma-ray-burst spectral shapes from 2 keV to 500 MeV SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts ID BATSE OBSERVATIONS; COMPTEL; MODELS AB We present three gamma-ray-burst spectra for bright bursts over very wide energy ranges. These were created from BATSE, COMPTEL, and OSSE data. The three spectra are for GRB 910503 (from 20 keV to 300 MeV), GRB 910601 (from 28 keV to 10.5 MeV), and GRB 910814 (from 103 keV to 500 MeV). A composite spectrum of 19 bright bursts is presented from 41 keV to 1.9 MeV (with no weak lines visible) for use in calculating average redshift corrections in cosmological models. Expanding fireball models with shocked synchrotron emission are predicted to have low-energy spectral slope (vF(v) proportional to v(alpha)) that asymptotically approaches alpha = 4/3 such that alpha should never exceed 4/3. This prediction is tested with more than 100 bright bursts with BATSE and Ginga data. Over 90% of the bursts have spectral slopes in agreement with this prediction. For only one burst (GRB 870303, which has reported cyclotron lines) can a strong case be made that the slope violates the model limit, and then only from 2-5 keV. C1 Yale Univ, Dept Phys, New Haven, CT 06520 USA. Univ Space Res Assoc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Utah, Dept Phys, Salt Lake City, UT 84112 USA. Grumman Aerosp Corp, Bethpage, NY 11714 USA. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Natl Univ Ireland Univ Coll Dublin, Dublin 4, Ireland. Univ Alabama, Ctr Space Plasma, Huntsville, AL 35899 USA. RP Schaefer, BE (reprint author), Yale Univ, Dept Phys, POB 208121, New Haven, CT 06520 USA. OI Dingus, Brenda/0000-0001-8451-7450 NR 24 TC 49 Z9 54 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP 696 EP 702 DI 10.1086/305058 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU308 UT WOS:000071704200021 ER PT J AU Bower, GA Green, RF Danks, A Gull, T Heap, S Hutchings, J Joseph, C Kaiser, ME Kimble, R Kraemer, S Weistrop, D Woodgate, B Lindler, D Hill, RS Malumuth, EM Baum, S Sarajedini, V Heckman, TM Wilson, AS Richstone, DO AF Bower, GA Green, RF Danks, A Gull, T Heap, S Hutchings, J Joseph, C Kaiser, ME Kimble, R Kraemer, S Weistrop, D Woodgate, B Lindler, D Hill, RS Malumuth, EM Baum, S Sarajedini, V Heckman, TM Wilson, AS Richstone, DO TI Kinematics of the nuclear ionized gas in the radio galaxy M84 (NGC 4374) SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, elliptical and lenticular, cD; galaxies, individual (M84); galaxies, kinematics and dynamics; galaxies, nuclei ID EMISSION-LINE NEBULAE; SPECTROSCOPY; CATALOG AB We present optical long-slit spectroscopy of the nucleus of the nearby radio galaxy M84 (NGC 4374 = 3C 272.1) obtained with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Our spectra reveal that the nuclear gas disk seen in the Wide Field Planetary Camera 2 imaging by Bower et al. is rotating rapidly. The velocity curve has an S-shape with a peak amplitude of 400 km s(-1) at 0".1 = 8 pc from the nucleus. To model the observed gas kinematics, we construct a thin Keplerian disk model that fits the data well if the rotation axis of the gas disk is aligned with the radio jet axis. These models indicate that the gasdynamics are driven by a nuclear compact mass of 1.5 x 10(9) M. with an uncertainty range of (0.9-2.6) x 10(9) M., and that the inclination of the disk with respect to the plane of the sky is 75 degrees-85 degrees. Of this nuclear mass, only less than or equal to 2 x 10(7) M. can possibly be attributed to luminous mass. Thus, we conclude that a dark compact mass (most likely a supermassive black hole) resides in the nucleus of M84. C1 Kitt Peak Natl Observ, Natl Opt Astron Observ, Tucson, AZ 85726 USA. Hughes STX Corp, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Adv Comp Concepts Inc, Potomac, MD 20854 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. RP Bower, GA (reprint author), Kitt Peak Natl Observ, Natl Opt Astron Observ, POB 26732,950 N Cherry Ave, Tucson, AZ 85726 USA. RI Kimble, Randy/D-5317-2012; heap, sara/E-2237-2012; Gull, Theodore/D-2753-2012; OI Gull, Theodore/0000-0002-6851-5380; Weistrop, Donna/0000-0001-8935-0792 NR 21 TC 104 Z9 106 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L111 EP + DI 10.1086/311109 PN 2 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500006 ER PT J AU Gardner, JP Hill, RS Baum, SA Collins, NR Ferguson, HC Fosbury, RAE Gilliland, RL Green, RF Gull, TR Heap, SR Lindler, DJ Malumuth, EM Micol, A Pirzkal, N Sandoval, JL Tolstoy, E Walsh, JR Woodgate, BE AF Gardner, JP Hill, RS Baum, SA Collins, NR Ferguson, HC Fosbury, RAE Gilliland, RL Green, RF Gull, TR Heap, SR Lindler, DJ Malumuth, EM Micol, A Pirzkal, N Sandoval, JL Tolstoy, E Walsh, JR Woodgate, BE TI The STIS parallel survey: Introduction and first results SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, observations; galaxies, evolution; galaxies, luminosity function, mass function; galaxies, statistics; surveys ID HUBBLE-SPACE-TELESCOPE; STAR-FORMING GALAXIES; DEEP SURVEY IMAGES; FAINT GALAXIES; POPULATION; CALIBRATION; REDSHIFTS; WFPC2 AB The installation of the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) allows for the first time two-dimensional optical and ultraviolet slitless spectroscopy of faint objects from space. The STIS Parallel Survey (SPS) routinely obtains broadband images and slitless spectra of random fields in parallel with HST observations using other instruments. The SPS is designed to study a wide variety of astrophysical phenomena, including the rate of star formation in galaxies at intermediate to high redshift through the detection of emission-line galaxies. We present the first results of the SPS, which demonstrate the capability of STIS slitless spectroscopy to detect and identify high-redshift galaxies. C1 Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Hughes STX Corp, Lanham, MD 20706 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Space Telescope European Coordinating Facil, D-85748 Garching, Germany. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Adv Comp Concepts Inc, Potomac, MD 20854 USA. RP Gardner, JP (reprint author), Natl Opt Astron Observ, Tucson, AZ 85726 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012; OI Gull, Theodore/0000-0002-6851-5380; Micol, Alberto/0000-0001-5594-3354; Fosbury, Robert/0000-0001-9975-8003 NR 21 TC 11 Z9 11 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L99 EP L102 DI 10.1086/311105 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500003 ER PT J AU Heap, SR Brown, TM Hubeny, I Landsman, W Yi, S Fanelli, M Gardner, JP Lanz, T Maran, SP Sweigart, A Kaiser, ME Linsky, J Timothy, JG Lindler, D Beck, T Bohlin, RC Clampin, M Grady, J Loiacono, J Krebs, C AF Heap, SR Brown, TM Hubeny, I Landsman, W Yi, S Fanelli, M Gardner, JP Lanz, T Maran, SP Sweigart, A Kaiser, ME Linsky, J Timothy, JG Lindler, D Beck, T Bohlin, RC Clampin, M Grady, J Loiacono, J Krebs, C TI Ultraviolet spectral dating of stars and galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, evolution; galaxies, stellar content; stars, atmospheres; ultraviolet, galaxies; ultraviolet, stars ID STELLAR AB An echelle spectrogram (R = 30,000) of the 2300-3100 Angstrom region in the ultraviolet spectrum of the F8 V star 9 Comae is presented. The observation is used to calibrate features in the mid-ultraviolet spectra of similar stars according to age and metal content. In particular, the spectral break at 2640 Angstrom is interpreted using the spectral synthesis code SYNSPEC. We use this feature to estimate the time since the last major star formation episode in the early-type galaxy LBDS 53W091 at redshift z = 1.55, whose rest-frame mid-ultraviolet spectrum, observed with the Keck Telescope, is dominated by the flux from similar stars that are at or near the main-sequence turnoff in that system (Spinrad et al.). Our result, 1 Gyr if the flux-dominating stellar population has a metallicity twice solar, or 2 Gyr for a more plausible solar metallicity, is significantly lower than the previous estimate and thereby relaxes constraints on cosmological parameters that were implied by the earlier work. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Hughes STX Corp, Lanham, MD 20706 USA. Univ Utrecht, NL-3508 TA Utrecht, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, Boulder, CO 80309 USA. Univ New Brunswick, Fredericton, NB E3B 5A3, Canada. Adv Comp Concepts, Potomac, MD 20854 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Clampin, mark/D-2738-2012; heap, sara/E-2237-2012; OI Brown, Thomas/0000-0002-1793-9968 NR 14 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L131 EP + DI 10.1086/311107 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500010 ER PT J AU Hutchings, JB Crenshaw, DM Kaiser, ME Kraemer, SB Weistrop, D Baum, S Bowers, CW Feinberg, LD Green, RF Gull, TR Hartig, GE Hill, G Lindler, DJ AF Hutchings, JB Crenshaw, DM Kaiser, ME Kraemer, SB Weistrop, D Baum, S Bowers, CW Feinberg, LD Green, RF Gull, TR Hartig, GE Hill, G Lindler, DJ TI Gas cloud kinematics near the nucleus of NGC 4151 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, kinematics and dynamics; galaxies, Seyfert ID NARROW-LINE REGION; ULTRAVIOLET-SPECTRUM; NGC-4151; TELESCOPE AB We report early observations with Space Telescope Imaging Spectrometer (STIS) of the nuclear region of NGC 4151. Direct images in [O II] and [O III] and slitless medium-dispersion spectral images of the H beta to [O III] region were obtained. A slitless UV spectral image was taken of the C IV 1550 Angstrom region. We present radial velocities and line ratios of similar to 40 clouds resolved in the narrow-line region (NLR). The kinematics suggest outflow within a biconical region about the nucleus, centered on the radio axis and viewed near the edge of the cones. A few high-velocity clouds are seen that do not fit this simple picture. Line ratios indicate that the NLR gas is photoionized by the central continuum source and that there may be a density gradient in the NLR. These observations are being followed by an extensive STIS program on NGC 4151. C1 Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Kitt Peak Natl Observ, Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Hutchings, JB (reprint author), Natl Res Council Canada, Dominion Astrophys Observ, 5071 W Saanich Rd, Victoria, BC V8X 4M6, Canada. RI Gull, Theodore/D-2753-2012; OI Gull, Theodore/0000-0002-6851-5380; Weistrop, Donna/0000-0001-8935-0792 NR 18 TC 65 Z9 65 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L115 EP + DI 10.1086/311100 PN 2 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500007 ER PT J AU Jenkins, EB Tripp, TM Fitzpatrick, EL Lindler, D Danks, AC Beck, TL Bowers, CW Joseph, CL Kaiser, ME Kimble, RA Kraemer, SB Robinson, RD Timothy, JG Valenti, JA AF Jenkins, EB Tripp, TM Fitzpatrick, EL Lindler, D Danks, AC Beck, TL Bowers, CW Joseph, CL Kaiser, ME Kimble, RA Kraemer, SB Robinson, RD Timothy, JG Valenti, JA TI Ultraviolet absorption lines from high-velocity gas in the Vela supernova remnant: New insights from Space Telescope Imaging Spectrograph echelle observations of HD 72089 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, abundances; ISM, individual (Vela supernova remnant); ISM, kinematics and dynamics; shock waves; stars, individual (HD 72089); supernova remnants ID PHOTOIONIZATION CROSS-SECTIONS; OSCILLATOR-STRENGTHS; POPULATION RATIOS; ANALYTIC FITS; GROUND-STATE; SI-II; INTERSTELLAR; ABUNDANCES; ELEMENTS; CARBON AB The star HD 72089 is located behind the Vela supernova remnant and shows a complex array of high-and low-velocity interstellar absorption features arising from shocked clouds. A spectrum of this star was recorded over the wavelength range 1196.4-1397.2 Angstrom at a resolving power of lambda/Delta lambda = 110,000 and a signal-to-noise ratio of 32 by the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. We have identified seven narrow components of C I and have measured their relative populations in excited fine-structure levels. Broader features at heliocentric velocities ranging from -70 to 130 km s(-1) are seen in C II, N I, O I, Si II, S II, and Ni II. In the high-velocity components, the unusually low abundances of N I and O I, relative to S II and Si II, suggest that these elements may be preferentially ionized to higher stages by radiation from hot gas immediately behind the shock fronts. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Adv Comp Concepts Inc, Potomac, MD 20854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hughes STX Corp, Lanham, MD 20706 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Comp Sci Corp, Cincinnati, OH 45202 USA. York Univ, Ctr Res Earth & Space Sci, N York, ON M3J 1P3, Canada. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Jenkins, EB (reprint author), Princeton Univ Observ, Princeton, NJ 08544 USA. RI Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 30 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L147 EP L150 DI 10.1086/311114 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500014 ER PT J AU Kimble, RA Woodgate, BE Bowers, CW Kraemer, SB Kaiser, ME Gull, TR Heap, SR Danks, AC Boggess, A Green, RF Hutchings, JB Jenkins, EB Joseph, CL Linsky, JL Maran, SP Moos, HW Roesler, F Timothy, JG Weistrop, DE Grady, JF Loiacono, JJ Brown, LW Brumfield, MD Content, DA Feinberg, LD Isaacs, MN Krebs, CA Krueger, VL Melcher, RW Rebar, FJ Vitagliano, HD Yagelowich, JJ Meyer, WW Hood, DF Argabright, VS Becker, SI Bottema, M Breyer, RR Bybee, RL Christon, PR Delamere, AW Dorn, DA Downey, S Driggers, PA Ebbets, DC Gallegos, JS Garner, H Hetlinger, JC Lettieri, RL Ludtke, CW Michika, D Nyquist, R Rose, DM Stocker, RB Sullivan, JF Van Houten, CN Woodruff, RA Baum, SA Hartig, GF Balzano, V Biagetti, C Blades, JC Bohlin, RC Clampin, M Doxsey, R Ferguson, HC Goudfrooij, P Hulbert, SJ Kutina, R McGrath, M Lindler, DJ Beck, TL Feggans, JK Plait, PC Sandoval, JL Hill, RS Collins, NR Cornett, RH Fowler, WB Hill, RJ Landsman, WB Malumuth, EM Standley, C Blouke, M Grusczak, A Reed, R Robinson, RD Valenti, JA Wolfe, T AF Kimble, RA Woodgate, BE Bowers, CW Kraemer, SB Kaiser, ME Gull, TR Heap, SR Danks, AC Boggess, A Green, RF Hutchings, JB Jenkins, EB Joseph, CL Linsky, JL Maran, SP Moos, HW Roesler, F Timothy, JG Weistrop, DE Grady, JF Loiacono, JJ Brown, LW Brumfield, MD Content, DA Feinberg, LD Isaacs, MN Krebs, CA Krueger, VL Melcher, RW Rebar, FJ Vitagliano, HD Yagelowich, JJ Meyer, WW Hood, DF Argabright, VS Becker, SI Bottema, M Breyer, RR Bybee, RL Christon, PR Delamere, AW Dorn, DA Downey, S Driggers, PA Ebbets, DC Gallegos, JS Garner, H Hetlinger, JC Lettieri, RL Ludtke, CW Michika, D Nyquist, R Rose, DM Stocker, RB Sullivan, JF Van Houten, CN Woodruff, RA Baum, SA Hartig, GF Balzano, V Biagetti, C Blades, JC Bohlin, RC Clampin, M Doxsey, R Ferguson, HC Goudfrooij, P Hulbert, SJ Kutina, R McGrath, M Lindler, DJ Beck, TL Feggans, JK Plait, PC Sandoval, JL Hill, RS Collins, NR Cornett, RH Fowler, WB Hill, RJ Landsman, WB Malumuth, EM Standley, C Blouke, M Grusczak, A Reed, R Robinson, RD Valenti, JA Wolfe, T CA STIS Invest Definit Team TI The on-orbit performance of the space telescope imaging spectrograph SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation, spectrographs; space vehicles; techniques, spectroscopic; ultraviolet, general ID DETECTOR AB The Space Telescope Imaging Spectrograph (STIS) was successfully installed into the Hubble Space Telescope (HST) in 1997 February, during the second HST servicing mission, STS-82. STIS is a versatile spectrograph, covering the 115-1000 nm wavelength range in a variety of spectroscopic and imaging modes that take advantage of the angular resolution, unobstructed wavelength coverage, and dark sky offered by the HST. In the months since launch, a number of performance tests and calibrations have been carried out and are continuing. These tests demonstrate that the instrument is performing very well. We present here a synopsis of the results to date. C1 Adv Comp Concepts Inc, NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Huges STX Corp, NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Kimble, RA (reprint author), Adv Comp Concepts Inc, NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012; heap, sara/E-2237-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 28 TC 181 Z9 182 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L83 EP + DI 10.1086/311102 PN 2 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500001 ER PT J AU McCaughrean, MJ Chen, H Bally, J Erickson, E Thompson, R Rieke, M Schneider, G Stolovy, S Young, E AF McCaughrean, MJ Chen, H Bally, J Erickson, E Thompson, R Rieke, M Schneider, G Stolovy, S Young, E TI High-resolution near-infrared imaging of the Orion 114-426 silhouette disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; infrared, ISM, continuum; infrared, ISM, lines and bands; ISM, individual (Orion Nebula); stars, formation ID MODEL SCATTERING ENVELOPES; YOUNG STELLAR OBJECTS; CIRCUMSTELLAR DISKS; ACCRETION DISKS; IMAGES; NEBULA AB We present the first high-resolution near-infrared images of the edge-on silhouette circumstellar disk, Orion 114-426, made using NICMOS on the Hubble Space Telescope. Images taken against the bright nebular background of the ionized hydrogen Pa alpha line at 1.87 mu m show the major axis of the disk to be approximately 20% smaller than at 0.6 mu m, from which we deduce the structure of the edge of the disk. Continuum images of diffuse polar lobes above and below the plane of the disk show a morphology and evolution with wavelength consistent with predictions for reflection nebulae in a diffuse envelope with large polar cavities, surrounding a thin, massless, Keplerian disk, centered on an otherwise hidden central star. We make use of our observations and reasonable assumptions about the underlying disk structure to show that the disk mass is at least 10 M+ and plausibly greater than or equal to 5 x 10(-4) M-.. C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP McCaughrean, MJ (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. NR 18 TC 48 Z9 48 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L157 EP + DI 10.1086/311110 PN 2 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500016 ER PT J AU Michael, E McCray, R Borkowski, KJ Pun, CSJ Sonneborn, G AF Michael, E McCray, R Borkowski, KJ Pun, CSJ Sonneborn, G TI High-velocity Ly alpha emission from SNR 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; hydrodynamics; supernovae, individual (SN 1987A); ultraviolet, ISM ID SN-1987A AB The high-velocity Ly alpha emission from SN 1987A observed with the Space Telescope Imaging Spectrograph (STIS) evidently comes from a reverse shock formed where the outer envelope of SN 1987A strikes ionized gas inside the inner circumstellar ring. The observations can be explained by a simple kinematic model, in which the Ly alpha emission comes from hydrogen atoms with radial velocity similar to 15,000 km s(-1) crossing a reverse shock in the shape of a slightly prolate ellipsoid with equatorial radius 4.8 x 10(17) cm or similar to 80% of the distance to the inner surface of the inner ring. N V lambda lambda 1239, 1243 emission, if present, has a net luminosity less than or similar to 30% times that of the Ly alpha emission. Future STIS observations should enable us to predict the time of impact with the inner ring and to determine unambiguously whether or not N V emission is present. These observations will offer a unique opportunity to probe the structure of SN 1987A's circumstellar environment and the hydrodynamics and kinetics of very fast shocks. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Michael, E (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 12 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L143 EP + DI 10.1086/311097 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500013 ER PT J AU Pian, E Fruchter, AS Bergeron, LE Thorsett, SE Frontera, E Tavani, M Costa, E Feroci, M Halpern, J Lucas, RA Nicastro, L Palazzi, E Piro, L Sparks, W Castro-Tirado, AJ Gull, T Hurley, K Pedersen, H AF Pian, E Fruchter, AS Bergeron, LE Thorsett, SE Frontera, E Tavani, M Costa, E Feroci, M Halpern, J Lucas, RA Nicastro, L Palazzi, E Piro, L Sparks, W Castro-Tirado, AJ Gull, T Hurley, K Pedersen, H TI Hubble Space Telescope imaging of the optical transient associated with GRB 970508 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, observations; galaxies, starburst; gamma rays, bursts; stars, formation ID GAMMA-RAY BURSTS; BLACK-HOLES; LUMINOSITY; STARS AB We report on Hubble Space Telescope observations of the optical transient (OT) discovered in the error box of the gamma-ray burst GRB 970508. The object was imaged on 1997 June 2 with the Space Telescope Imaging Spectrograph and Near-Infrared Camera and Multiobject Spectrometer. The observations reveal a pointlike source with R = 23.1 +/- 0.2 and H = 20.6 +/- 0.3, in agreement with the power-law temporal decay seen in groundbased monitoring. Unlike the case of GRB 970228, no nebulosity is detected surrounding the OT of GRB 970508. We set very conservative upper limits of R similar to 24.5 and H similar to 22.2 on the brightness of any underlying extended source. If this subtends a substantial fraction of an arcsecond, then the R-band limit is similar to 25.5. In combination with Keck spectra that show Mg I absorption and [O II] emission at a redshift of z = 0.835, om observations suggest that the OT is located in a star-forming galaxy with total luminosity 1 order of magnitude lower than the knee of the galaxy luminosity function, L-*. Such galaxies are now thought to harbor the majority of star formation at z similar to 1; therefore, these observations may provide support for a link between GRBs and star formation. C1 CNR, Ist Tecnol & Studio Radiazioni Extraterr, I-40129 Bologna, Italy. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Princeton Univ, Joseph Henry Labs, Dept Phys, Princeton, NJ 08544 USA. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. CNR, Ist Fis Cosm, I-20133 Milan, Italy. CNR, Ist Astrofis Spaziale, I-00044 Frascati, Italy. Inst Nacl Invest Agr, Lab Astrofis Espacial & Fis Fundamental, E-28080 Madrid, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20071 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Copenhagen Univ Observ, DK-2100 Copenhagen, Denmark. RP Pian, E (reprint author), CNR, Ist Tecnol & Studio Radiazioni Extraterr, Via Gobetti 101, I-40129 Bologna, Italy. RI Gull, Theodore/D-2753-2012; PIRO, LUIGI/E-4954-2013; Nicastro, Luciano/F-5866-2015; Palazzi, Eliana/N-4746-2015; OI Gull, Theodore/0000-0002-6851-5380; PIRO, LUIGI/0000-0003-4159-3984; Nicastro, Luciano/0000-0001-8534-6788; Palazzi, Eliana/0000-0002-8691-7666 NR 46 TC 55 Z9 55 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L103 EP + DI 10.1086/311101 PN 2 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500004 ER PT J AU Sahai, R Hines, DC Kastner, JH Weintraub, DA Trauger, JT Rieke, MJ Thompson, RI Schneider, G AF Sahai, R Hines, DC Kastner, JH Weintraub, DA Trauger, JT Rieke, MJ Thompson, RI Schneider, G TI The structure of the prototype bipolar protoplanetary nebula CRL 2688 (Egg Nebula): Broadband, polarimetric, and H-2 line imaging with NICMOS on the Hubble Space Telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, reflection nebulae; stars, AGB and post-AGB; stars, circumstellar matter; stars, individual (CRL 2688); stars, mass loss; techniques, polarimetric ID CRL-2688; AFGL-2688 AB High-resolution near-infrared (1.65-2.1 mu m) images and 2 mu m polarimetric images of the inner 19".5 x 19".3 region of the bipolar protoplanetary nebula CRL 2688, taken with the newly installed Near-Infrared Camera and Multiobject Spectrometer (NICMOS) aboard the Hubble Space Telescope (HST), are reported. The NICMOS images reveal a wealth of structure also seen in HST Wide Field Planetary Camera 2 images but not detected in previous, ground-based near-infrared imaging studies. In particular, we detect a system of concentric arcs centered on, and twin "searchlight beams" emanating from, the obscured central star. The images also show two sharply bounded spindle-shaped polar cavities with point-symmetric structure, and the 2.122 mu m H-2 S(1) upsilon = 1-0 emission-line image clearly resolves the sharp interface between the high-velocity outflow that produces these polar cavities and the surrounding slow outflow that forms the extended nebula. The H-2 image also resolves the bright equatorial H, emission into distinct components and elucidates their detailed morphologies. We have discovered, within the dark lane that bifurcates the bipolar lobes of CRL 2688, a compact source of unpolarized light. Our imaging polarimetry shows that this source is not the post-asymptotic giant branch star that illuminates the nebula; we conclude that the compact source is a companion star. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, MS 183-900, Pasadena, CA 91109 USA. NR 24 TC 90 Z9 90 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L163 EP + DI 10.1086/311108 PN 2 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500017 ER PT J AU Sahu, KC Shaw, RA Kaiser, ME Baum, SA Ferguson, HC Hayes, JJE Gull, TR Hill, RJ Hutchings, JB Kimble, RA Plait, P Woodgate, BE AF Sahu, KC Shaw, RA Kaiser, ME Baum, SA Ferguson, HC Hayes, JJE Gull, TR Hill, RJ Hutchings, JB Kimble, RA Plait, P Woodgate, BE TI Imaging and spectroscopy of arcs around the most luminous X-ray cluster, RX J1347.5-1145 SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; galaxies, clusters, individual (RX J1347.5-1145); gravitational lensing ID GALAXIES; MASS AB The cluster RX J1347.5-1145, the most luminous cluster in the X-ray wavelengths, was imaged with the newly installed Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. Its relatively high redshift (0.451) and luminosity indicate that this is one of the most massive of all known clusters. The STIS images unambiguously show several arcs in the cluster. The largest two arcs (>5" length) are symmetrically situated on opposite sides of the cluster, at a distance of similar to 35" from the central galaxy. The STIS images also show approximately 100 faint galaxies within the radius of the arcs whose combined luminosity is similar to 4 x 10(11) L-.. We also present ground-based spectroscopic observations of the northern are that show one clear emission line at similar to 6730 Angstrom, with a very faint continuum on either side. The emission line is consistent with an identification as [O II] lambda 3727, implying a redshift of 0.81 for this are. The southern are shows a faint continuum but no emission features. The surface mass within the radius of the arcs (240 kpc), as derived from the gravitational lensing, is similar to 6.3 x 10(14) M-.. The resultant mass-to-light ratio of similar to 1200 is higher than what is seen in many clusters but smaller than the value recently derived for some "dark" X-ray clusters (Hattori et al.). The total surface mass derived from the X-ray flux within the radius of the arcs is similar to(2.1-6.8) x 10(14) M-., which implies that the ratio of the gravitational to the X-ray mass is similar to 1-3. The surface gas mass within this radius is similar to 3.5 x 10(13) M-., which implies that at least 6% of the total mass within this region is baryonic. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Huges STX Corp, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Adv Comp Concepts, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sahu, KC (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 14 TC 33 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L125 EP + DI 10.1086/311112 PN 2 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500009 ER PT J AU Schultz, AB Allard, F Clampin, M McGrath, M Bruhweiler, FC Valenti, JA Plait, P Hulbert, S Baum, S Woodgate, BE Bowers, CW Kimble, RA Maran, SP Moos, HW Roesler, F AF Schultz, AB Allard, F Clampin, M McGrath, M Bruhweiler, FC Valenti, JA Plait, P Hulbert, S Baum, S Woodgate, BE Bowers, CW Kimble, RA Maran, SP Moos, HW Roesler, F TI First results from the Space Telescope Imaging Spectrograph: Optical spectra of Gliese 229B SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, general; stars, individual (Gl 229B); stars, low-mass, brown dwarfs ID LOW MASS STARS; BROWN DWARF; INFRARED SPECTRUM; EVOLUTIONARY; PLANETS AB We report the first Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) CCD spectroscopy of the bona fide brown dwarf Gliese 229B. The optical spectrum shows absorptions of Cs I at 8944 Angstrom and water vapor bands at 9300-9600 Angstrom. Strong CaH, FeH, TiO, and VO bands observed in late M dwarfs are absent from the spectrum of Gliese 229B. The formation of dust grains may explain the absence of strong atomic lines and molecular bands of these refractory elements. The broad spectral coverage obtained helps resolve current speculations about the presence of dust clouds in the atmosphere of cool brown dwarfs. We find the slope of the STIS/CCD spectrum and the lack of flux detected shortward of 8000 Angstrom strongly supports the presence of dust hazes suspended in the photosphere of GI 229B rather than a complete settling of the grains to regions below the photosphere. C1 Space Telescope Sci Inst, Comp Sci Corp, Astron Program, Baltimore, MD 21218 USA. Wichita State Univ, Dept Phys, Wichita, KS 67260 USA. Catholic Univ Amer, Dept Phys, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Adv Comp Concepts, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Schultz, AB (reprint author), Space Telescope Sci Inst, Comp Sci Corp, Astron Program, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Woodgate, Bruce/D-2970-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012 NR 31 TC 29 Z9 29 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L181 EP L184 DI 10.1086/311103 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500021 ER PT J AU Sonneborn, G Pun, CSJ Kimble, RA Gull, TR Lundqvist, P McCray, R Plait, P Boggess, A Bowers, CW Danks, AC Grady, J Heap, SR Kraemer, S Lindler, D Loiacono, J Maran, SP Moos, HW Woodgate, BE AF Sonneborn, G Pun, CSJ Kimble, RA Gull, TR Lundqvist, P McCray, R Plait, P Boggess, A Bowers, CW Danks, AC Grady, J Heap, SR Kraemer, S Lindler, D Loiacono, J Maran, SP Moos, HW Woodgate, BE TI Spatially resolved STIS spectroscopy of SN 1987A: Evidence for shock interaction with circumstellar gas SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; supernova remnants; supernovae, individual (SN 1987A) ID SN-1987A; SUPERNOVA-1987A; EMISSION; REMNANT AB Visual and ultraviolet spatially resolved (similar to 0".1) spectra of SN 1987A obtained on days 3715 and 3743 with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope show that the high-velocity supernova debris is colliding with circumstellar gas. Very broad Ly alpha emission with velocities extending to similar to+/- 20,000 km s(-1) originates inside the inner circumstellar ring and appears to fill most of the surface area within 0".67 +/- 0".03 (0.14 pc at a distance of 50 kpc) of the ring's center. The observed Ly alpha flux from the shocked ejecta is (1.85 +/- 0.53) x 10(-13) and (1.25 +/- 0.51) x 10(-12) ergs cm(-2) s(-1) after correcting for extinction. A spatially unresolved blueshifted emission feature was discovered in H alpha (and other lines) on the inner ring at position angle 31 degrees +/- 8 degrees. The H alpha emission extends to -250 km s(-1) with no corresponding redshifted emission. This highly localized interaction appears to be the initial contact of the supernova blast wave with an inward protrusion of the inner ring. The broad Ly alpha emission and the "hot spot" are separate interaction phenomena associated with the reverse and forward shocks, respectively. We also find that the size of the inner ring in forbidden lines of oxygen has a dependence on ionization potential, in agreement with photoionization models of the ring. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Stockholm Observ, S-13336 Saltsjobaden, Sweden. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Appl Comp Concepts, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hughes STX, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Space Sci Directorate, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Sonneborn, G (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Sonneborn, George/D-5255-2012; Woodgate, Bruce/D-2970-2012; Kimble, Randy/D-5317-2012; heap, sara/E-2237-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 20 TC 49 Z9 49 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L139 EP + DI 10.1086/311106 PN 2 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500012 ER PT J AU Stolovy, SR Burton, MG Erickson, EF Kaufman, MJ Chrysostomou, A Young, ET Colgan, SWJ Axon, DJ Thompson, RI Rieke, MJ Schneider, G AF Stolovy, SR Burton, MG Erickson, EF Kaufman, MJ Chrysostomou, A Young, ET Colgan, SWJ Axon, DJ Thompson, RI Rieke, MJ Schneider, G TI NICMOS 2 micron continuum and H-2 images of OMC-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, close; infrared, ISM, continuum; ISM, individual (OMC-1); ISM, jets and outflows; ISM, molecules; shock waves ID ORION MOLECULAR CLOUD; HERBIG-HARO OBJECTS; SUBARCSECOND-RESOLUTION; EMISSION; NEBULA; REGION; KL; HYDROGEN; PROFILES; OUTFLOWS AB The core of OMC-1 has been imaged with the Near-Infrared Camera and Multiobject Spectrometer (NICMOS) on board the Hubble Space Telescope at 0".2 resolution in 1% filters at 2.12 and 2.15 mu m, revealing intricate structures in both continuum and shocked molecular hydrogen line emission. Numerous H-2-emitting clumps surrounding the BN/KL region have been resolved for the first time, several of which exhibit prototypical bow-shock morphologies with V-shaped tips. We interpret these to be lower excitation analogs of similar structures similar to 2' northwest of the core observed with ground-based telescopes. Many of the elongated H-2 structures and bow-shock features appear to radiate outward from a region within a few arcseconds of radio source I, which suggests that the H-2 energetics are dominated by one or more outflow sources in this region. However, the orientations of some features are unrelated to this apparent outflow pattern. The deeply embedded, suspected outflow source I remains undetected at 2 mu m, although two faint new continuum sources have been detected within similar to 1" of it. The newly resolved H-2 features with bow-shock morphologies are located in regions previously identified as bow shocks by highly blueshifted components in their line profiles. In contrast, regions of H-2 emission that are diffuse in the NICMOS image have broad, smooth line profiles. Several continuum features have an arclike appearance, which suggests interactions of winds with the ambient medium. At least 40 stellar or protostellar continuum sources have been detected, including at least one proplyd and four pairs of binary stars. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Joint Astron Ctr, Hilo, HI 96720 USA. Space Telescope Sci Inst, ESA, Div Astrophys, Baltimore, MD 21218 USA. RP Stolovy, SR (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RI Colgan, Sean/M-4742-2014 NR 32 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L151 EP + DI 10.1086/311111 PN 2 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500015 ER PT J AU Walborn, NR Danks, AC Sembach, KR Bohlin, RC Jenkins, EB Gull, TR Lindler, DJ Feggans, JK Hulbert, SJ Linsky, J Hutchings, JB Joseph, CL AF Walborn, NR Danks, AC Sembach, KR Bohlin, RC Jenkins, EB Gull, TR Lindler, DJ Feggans, JK Hulbert, SJ Linsky, J Hutchings, JB Joseph, CL TI Space Telescope Imaging Spectrograph observations of the interstellar velocity structure and chemical composition toward the Carina Nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, abundances; ISM, individual (NGC 3372); ISM, structures; ultraviolet, ISM ID INTER-STELLAR MEDIUM; LINES; ABUNDANCES; ABSORPTION; ELEMENTS; CARBON; STATE; GAS AB We have observed the O-type star CPD -59 degrees 2603 in the Carina Nebula with the Space Telescope Imaging Spectrograph near-UV and far-UV high-resolution echelles, at a resolving power of similar to 110,000 (FWHM) and S/N similar to 30. This sight line has complex velocity and excitation structure in the interstellar absorption lines, corresponding to three distinct regions: very high velocity components formed within the nebula; a warm, expanding H II region; and cool, low-velocity gas near the Sun. The ME I and Mg II profiles show many components, with velocities extending from -235 to +123 kms(-1). We have derived physical conditions in the expanding H II region from Si IV doublet and the excited fine-structure lines of C I. Heavy elements (O, Ni, Cu, Ga) are present in the low-velocity gas, and their abundances indicate depletions consistent with nearby, cool diffuse clouds. (CO)-C-12 is detected in just one low-velocity component, suggesting different amounts of processing among the clouds near the Sun. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Hughes STX, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Adv Comp Concepts, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. RP Walborn, NR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Gull, Theodore/D-2753-2012; Jenkins, Edward/P-5684-2014 OI Gull, Theodore/0000-0002-6851-5380; Jenkins, Edward/0000-0003-1892-4423 NR 28 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1998 VL 492 IS 2 BP L169 EP + DI 10.1086/311113 PN 2 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU310 UT WOS:000071704500018 ER PT J AU Chen, G Katsaros, K Chapron, B Tournadre, J Vandemark, D AF Chen, G Katsaros, K Chapron, B Tournadre, J Vandemark, D TI A new look at the diurnal variation of global oceanic precipitation from the ocean TOPography Experiment (TOPEX) and the TOPEX Microwave Radiometer (TMR) SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SSM/I DATA; CYCLE; CONVECTION; VARIABILITY; RAINFALL AB New results on the diurnal variation of global oceanic precipitation are obtained by using one year's TOPEX (ocean TOPography EXperiment) and TMR (TOPEX Microwave Radiometer) data, derived from the dual-frequency (K-u and C band) capacity of the altimeter and the non-Sun-synchronous orbit of the satellite. The diurnal variation is characterized by a three-maximum structure which peaks al 00:00, 08:00, and 16:00 lo cal time. The midnight-mo mi ng-afternoon maxima and dawn-noon-evening minima pattern seems to correlate with the results of most previous studies and to offer a unified picture of the diurnal variation of oceanic rainfall. A slight daytime (06:00-18:00) preference of oceanic precipitation appears to be significant in all seasons with the day/night ratio varying from 1.032 to 1.141 and the annual mean being 1.082. Examination of the geographical distribution of the timing of diurnal variation shows that the majority of the world oceans favour an afternoon maximum and an evening minimum. Moreover, the northern hemisphere is more coherent in reaching its maximum, while the southern hemisphere in reaching its minimum. In addition, the mechanisms responsible for the diurnal variations are discussed. C1 Ocean Univ Qingao, Ocean Remote Sensing Inst, Qingdao 266003, Peoples R China. IFREMER, Ctr Brest, Dept Oceanog Spatiale, F-29280 Plouzane, France. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Island, VA 23337 USA. RP Chen, G (reprint author), Ocean Univ Qingao, Ocean Remote Sensing Inst, 5 Yushan Rd, Qingdao 266003, Peoples R China. RI Chapron, Bertrand/O-6527-2015; tournadre, jean/F-8402-2010 OI tournadre, jean/0000-0003-1159-4388 NR 19 TC 3 Z9 3 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 10 PY 1998 VL 19 IS 1 BP 171 EP 180 DI 10.1080/014311698216495 PG 10 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA YT715 UT WOS:000071635700012 ER PT J AU Stewart, JB Engman, ET Feddes, RA Kerr, YH AF Stewart, JB Engman, ET Feddes, RA Kerr, YH TI Scaling up in hydrology using remote sensing: summary of a workshop SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID FIELD EXPERIMENT; HAPEX-SAHEL; SURFACE; ATMOSPHERE AB This paper summarises the presentations and recommendations of an international Workshop on 'Scaling up in hydrology using remote sensing' which was held at the Institute of Hydrology in June 1996. The Workshop highlighted considerable gaps in our knowledge of scaling issues and strongly recommended further analysis of existing data sets to assess the accuracy of remotely-sensed algorithms and assessment of propagation of errors in remote sensing through models to their outputs. To facilitate these investigations the Workshop highlighted these essential requirements-to make data sets more readily available and user friendly, develop formal programmes to compare algorithms and earmark funds specifically for these analysis programmes. C1 Inst Hydrol, Wallingford OX10 8BB, Oxon, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Agr Univ Wageningen, Dept Water Resources, NL-6709 PA Wageningen, Netherlands. UPS 47, CNRS, CNES, CESBIO, F-31401 Toulouse 4, France. RP Stewart, JB (reprint author), Univ Southampton, Dept Geog, Highfield, Southampton SO17 1BJ, Hants, England. NR 14 TC 17 Z9 18 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 10 PY 1998 VL 19 IS 1 BP 181 EP 194 DI 10.1080/014311698216503 PG 14 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA YT715 UT WOS:000071635700013 ER PT J AU Raman, G Taghavi, R AF Raman, G Taghavi, R TI Coupling of twin rectangular supersonic jets SO JOURNAL OF FLUID MECHANICS LA English DT Article ID INSTABILITY AB Twin jet plumes on aircraft can couple, producing dynamic pressures significant enough to cause structural fatigue. For closely spaced jets with a moderate aspect ratio (e.g. 5), previous work has established that two coupling modes (antisymmetric and symmetric) are kinematically permissible. However, the dynamics of twin-jet coupling have remained unexplored. In this paper a more fundamental assessment of the steady and unsteady aspects of twin-jet coupling is attempted. While we document and discuss the nozzle spacings and Mach numbers over which phase-locked coupling occurs, our concentration is much more on answering the following questions: (a) What mechanism causes the jets to couple in one mode or the other? (b) Why do the jets switch from one mode to another? (c) Are the two modes mutually exclusive or do they overlap at the transition point? Our results reveal, among many things, the following. (i) For very closely spaced twin jets in the side-by-side configuration phased feedback based on source to nozzle exit distance of adjacent jets does not fully explain the coupling modes. However, the 'null' phase regions surrounding the jets where the phase of an acoustic wavefront (arriving from downstream) does not vary appears to correlate well with the existence of the symmetric mode. When the 'null' regions of adjacent jets do not overlap antisymmetric coupling occurs and when they do overlap the jets couple symmetrically. We provide a simple correlation using a parameter (a) that can be used as a simple test to determine the mode of coupling. (ii) The switch from the antisymmetric to the symmetric mode of coupling appears to occur because of an abrupt shift in the effective screech source from the third to the fourth shock, which in turn causes the 'null' phase region surrounding the jets to grow abruptly and overlap. (iii) The two modes are mutually exclusive. Our results provide considerable insight into the twin-jet coupling problem and offer hope for designing twin-jet configurations that minimize damage to aircraft components. C1 NASA, Lewis Res Ctr Grp, NYMA Inc, Expt Fluid Dynam Sect, Brook Pk, OH 44142 USA. Univ Kansas, Dept Aerosp Engn, Lawrence, KS 66045 USA. RP Raman, G (reprint author), NASA, Lewis Res Ctr Grp, NYMA Inc, Expt Fluid Dynam Sect, Brook Pk, OH 44142 USA. NR 29 TC 21 Z9 21 U1 1 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JAN 10 PY 1998 VL 354 BP 123 EP 146 DI 10.1017/S0022112097007441 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YV886 UT WOS:000071873700005 ER PT J AU Han, J AF Han, J TI Energetics and structures of fullerene crop circles SO CHEMICAL PHYSICS LETTERS LA English DT Article ID TOROIDAL FORMS; CARBON NANOTUBES; TORI AB The energetics and structures of carbon tori are studied using molecular simulation. They include circular and polygonal tori, formed by bending (n, II) tubes and by joining (n, n) and (n + 1, n - 1) or (n + 2, n - 2) tubes with pentagon-heptagon defects, respectively, in which n = 5, 8 and 10. The strain energy of a circular and polygonal torus decreases by D-2 and D-1, respectively, where D is the torus diameter. Comparisons in average and local maximum strain suggest that defect-free circular tori are more energetically stable and kinetically accessible than defective polygonal tori. This confirms the hypothesis that circular tori are the predominant constituents of the observed fullerene crop circles in laser-grown single-wall carbon nanotubes. (C) 1998 Elsevier Science B.V. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, T27A-1, Moffett Field, CA 94035 USA. NR 20 TC 35 Z9 35 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JAN 9 PY 1998 VL 282 IS 2 BP 187 EP 191 DI 10.1016/S0009-2614(97)01267-0 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZA077 UT WOS:000072326600014 ER PT J AU Martin, JML Lee, TJ Taylor, PR AF Martin, JML Lee, TJ Taylor, PR TI A purely ab initio spectroscopic quality quartic force field for acetylene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATION-ROTATION SPECTRA; GAUSSIAN-BASIS SETS; TOTAL ATOMIZATION ENERGIES; CONSISTENT BASIS-SETS; HARMONIC FREQUENCIES; WAVE-FUNCTIONS; C-13-CONTAINING ACETYLENE; ANHARMONIC RESONANCES; POLYATOMIC-MOLECULES; ACCURATE CALCULATION AB The quartic force field of acetylene was determined using the CCSD(T) method (coupled cluster with all single and double substitutions and quasiperturbative inclusion of connected triple excitations) with a variety of one-particle basis sets of the atomic natural orbital, correlation consistent, and augmented correlation consistent types. The harmonic pi(g) bending frequency omega(4) and the corresponding anharmonicity omega(4)-nu(4) are both found to be extremely sensitive to the basis set used, in particular to the presence of a sufficient complement of diffuse functions, (Due to symmetry cancellation, the corresponding effect on the pi(u) mode, i.e., omega(5) and omega(5)-nu(5), is much weaker.) Similar phenomena are observed more generally in bending modes for molecules that possess carbon-carbon multiple bonds. Tentative explanations are advanced, Our best computed quartic force field, which combines CCSD(T)/[6s5p4d3f2g/4s3p2d1f] anharmonicities with a geometry and harmonic frequencies that additionally include inner-shell correlation effects, reproduces the observed fundamentals for HCCH, HCCD, DCCD, (HCCH)-C-13, and (HCCH)-C-13-C-13 with a mean absolute error of 1.3 cm(-1), and the equilibrium rotational constant to four decimal places, without any empirical adjustment. Anharmonicity and quartic resonance constants are in excellent agreement with the recent determination of Temsamani and Herman [J. Chem. Phys. 103, 6371 (1995)], except for the vibrational l-doubling constant R-45, for which an adjustment to the computed force field is proposed. (C) 1998 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Weizmann Inst Sci, Dept Organ Chem, IL-76100 Rehovot, Israel. Univ Calif San Diego, Dept Chem & Biochem, San Diego, CA 92186 USA. Univ Calif San Diego, San Diego Supercomp Ctr, San Diego, CA 92186 USA. RP Lee, TJ (reprint author), NASA, Ames Res Ctr, MS230-3, Moffett Field, CA 94035 USA. RI Lee, Timothy/K-2838-2012; Martin, Jan/A-7457-2008 OI Martin, Jan/0000-0002-0005-5074 NR 77 TC 104 Z9 105 U1 2 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 8 PY 1998 VL 108 IS 2 BP 676 EP 691 DI 10.1063/1.475429 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YP022 UT WOS:000071233400034 ER PT J AU Hudgins, DM Sandford, SA AF Hudgins, DM Sandford, SA TI Infrared spectroscopy of matrix isolated polycyclic aromatic hydrocarbons. 1. PAHs containing two to four rings SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR VIBRATIONS; CONDENSED AROMATICS; EMISSION-SPECTRA; ISOLATED NAPHTHALENE; GAS-CHROMATOGRAPHY; ELECTRONIC-SPECTRA; RADICAL CATIONS; BANDS; ANTHRACENE; TEMPERATURE AB Matrix isolation techniques have been used to measure the mid-infrared spectra of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, anthracene, phenanthrene, 1,2-benzanthracene, chrysene, pyrene, tetracene, and triphenylene. The band positions and relative strengths are compared to previous laboratory studies, where available, and with available theoretical calculations.(1) Comparisons with theory indicate that density functional theory (DFT) does an excellent job of describing the majority of the infrared active fundamentals of the PAHs considered here. Band positions typically match to within 5 cm(-1), with the worst mismatches usually no more than 15 cm(-1). Matches in band strengths are not as precise but, with the exception of the CH stretching bands, are generally good to better than 35% for most strong and moderate bands and to factors of 2 to 3 for weaker bands. Theory predicts CH stretching band strengths that are about a factor of 2 times too strong. The laboratory spectra contain large numbers of bands due to overtone/combination modes that are not considered in the calculations, and while most of these bands are weak, some can be moderately strong. Finally, comparisons between the infrared spectra of matrix isolated PAHs and a common family of interstellar emission bands confirm that neutral PAHs do not provide a good fit to the astronomical data. Neutral PAHs produce features having appropriate frequencies but generally inappropriate strengths. Nevertheless, significant contributions from PAH neutrals may be required to explain the spectra of a few less energetic astronomical environments. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hudgins, DM (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 65 TC 125 Z9 126 U1 1 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JAN 8 PY 1998 VL 102 IS 2 BP 329 EP 343 DI 10.1021/jp9834816 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YR894 UT WOS:000071542200004 ER PT J AU Hudgins, DM Sandford, SA AF Hudgins, DM Sandford, SA TI Infrared spectroscopy of matrix isolated polycyclic aromatic hydrocarbons. 2. PAHs containing five or more rings SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CONDENSED AROMATICS; MOLECULAR VIBRATIONS; EMISSION FEATURES; CATIONS; SPECTRA; PENTACENE; CORONENE; ANIONS; DUST AB Matrix isolation techniques have been used to measure the mid-infrared spectra of the polycyclic aromatic hydrocarbons (PAHs) benzo[e]pyrene, pentacene, perylene, benzo[ghi]perylene, coronene, and 1,12:2,3:4,5: 6,7:8,9:10,11-hexabenzocoronene. The observed band positions and relative strengths are compared to previous lab studies and with theoretical calculations, where available.(1) Agreement with other available laboratory data is excellent. Comparisons with theory indicate that density functional theory (DFT) does an excellent of describing the majority of the infrared active fundamentals of the PAHs considered here. Band positions typically agree to better than 5 cm(-1), with the worst disparities usually being less than 15 cm(-1). Matches in band strengths are not as precise, but are generally good to better than 30-50% for most strong and moderate bands and are good to factors of 2-4 for weaker bands. The theory predicts CH stretching band strengths that are too strong by a factor of about 2. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hudgins, DM (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 29 TC 100 Z9 101 U1 1 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JAN 8 PY 1998 VL 102 IS 2 BP 344 EP 352 DI 10.1021/jp983482y PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YR894 UT WOS:000071542200005 ER PT J AU Hudgins, DM Sandford, SA AF Hudgins, DM Sandford, SA TI Infrared spectroscopy of matrix isolated polycyclic aromatic hydrocarbons. 3. Fluoranthene and the benzofluoranthenes SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CATIONS; DUST AB Matrix isolation techniques have been used to measure the 4000-500 cm(-1) infrared spectra of the polycyclic aromatic hydrocarbons (PAHs) fluoranthene, benzo[a]fluoranthene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, and benzo[ghi]fluoranthene. For the PAHs where previous matrix isolation and gasphase laboratory studies are available, agreements between the data sets are generally very good. While the fluoranthenes as a class produce infrared spectra that share many of the same characteristics of the spectra of PAHs containing only benzenoid moieties, for comparably sized molecules, the fluoranthenes tend to produce more absorption bands overall and considerably more and stronger bands in the 1550-1350 cm(-1) range. These differences are largely due to the presence of the five-membered cyclopentadienyl ring characteristic of the family. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hudgins, DM (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 21 TC 54 Z9 54 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JAN 8 PY 1998 VL 102 IS 2 BP 353 EP 360 DI 10.1021/jp983483q PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA YR894 UT WOS:000071542200006 ER PT J AU Schramm, DN AF Schramm, DN TI Primordial nucleosynthesis SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT National-Academy-of-Sciences Colloquium on the Age of the Universe, Dark Matter, and Structure Formation CY MAR 21-23, 1997 CL ARNOLD & MABEL BECKMAN CTR NAT ACAD SCI & ENGN, IRVINE, CALIFORNIA SP Natl Acad Sci HO ARNOLD & MABEL BECKMAN CTR NAT ACAD SCI & ENGN ID BIG-BANG NUCLEOSYNTHESIS; NEUTRON LIFETIME; HALO-STARS; INTERSTELLAR-MEDIUM; ULTRACOLD NEUTRONS; DARK-MATTER; ABUNDANCE; LITHIUM; UNIVERSE; HE-3 AB With the advent of the new extragalactic deuterium observations, Big Bang nucleosynthesis (BBN) is on the verge of undergoing a transformation. In the past, the emphasis has been on demonstrating the concordance of the BBN model with the abundances of the light isotopes extrapolated back to their primordial values by using stellar and galactic evolution theories, As a direct measure of primordial deuterium is converged upon, the nature of the field will shift to using the much more precise primordial D/H to constrain the more flexible stellar and galactic evolution models (although the question of potential systematic error in He-4 abundance determinations remains open). The remarkable success of the theory to date in establishing the concordance has led to the very robust conclusion of BBN regarding the baryon density. This robustness remains even through major model variations such as an assumed first-order quark-hadron phase transition. The BBN constraints on the cosmological baryon density are reviewed and demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. Comparison of baryonic density arguments from Lyman-alpha clouds, x-ray gas in clusters, and the microwave anisotropy are made. C1 Univ Chicago, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermilab, Batavia, IL 60510 USA. RP Schramm, DN (reprint author), Univ Chicago, 5640 S Ellis Ave, Chicago, IL 60637 USA. EM dns@oddjob.uchicago.edu NR 83 TC 6 Z9 6 U1 0 U2 2 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JAN 6 PY 1998 VL 95 IS 1 BP 42 EP 46 DI 10.1073/pnas.95.1.42 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YQ846 UT WOS:000071429500010 PM 9419322 ER PT J AU Mushotzky, R AF Mushotzky, R TI X-ray emission from clusters and groups of galaxies SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article; Proceedings Paper CT National-Academy-of-Sciences Colloquium on the Age of the Universe, Dark Matter, and Structure Formation CY MAR 21-23, 1997 CL ARNOLD & MABEL BECKMAN CTR NAT ACAD SCI & ENGN, IRVINE, CALIFORNIA SP Natl Acad Sci HO ARNOLD & MABEL BECKMAN CTR NAT ACAD SCI & ENGN AB Recent major advances in x-ray imaging and spectroscopy of clusters have allowed the determination of their mass and mass profile out to approximate to 1/2 the virial radius. In rich clusters, most of the baryonic mass is in the gas phase, and the ratio of mass in gas/stars varies by a factor of 2-4. The baryonic fractions vary by a factor of approximate to 3 from cluster to cluster and almost always exceed 0.09 h(50)(-[3/2]) and thus are in fundamental conflict with the assumption of Ohm = 1 and the results of big bang nucleosynthesis. The derived Fe abundances are 0.2-0.45 solar, and the abundances of O and Si for low redshift systems are 0.6-1.0 solar. This distribution is consistent with an origin in pure type II supernova. The amount of light and energy produced by these supernovae is very large, indicating their importance in influencing the formation of clusters and galaxies. The lack of evolution of Fe to a redshift of z approximate to 0.4 argues for very early enrichment of the cluster gas. Groups show a wide range of abundances, 0.1-0.5 solar. The results of an x-ray survey indicate that the contribution of groups to the mass density of the universe is likely to be larger than 0.1 h(50)(-2). Many of the very poor groups have large x-ray halos and are filled with small galaxies whose velocity dispersion is a good match to the x-ray temperatures. C1 NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mushotzky, R (reprint author), NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 45 TC 4 Z9 4 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JAN 6 PY 1998 VL 95 IS 1 BP 72 EP 77 DI 10.1073/pnas.95.1.72 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YQ846 UT WOS:000071429500015 PM 9419327 ER PT J AU McGlynn, T AF McGlynn, T TI NASA's SkyView SO SCIENCE LA English DT Letter C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McGlynn, T (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 2 PY 1998 VL 279 IS 5347 BP 13 EP 13 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YP866 UT WOS:000071323900008 ER PT J AU Wennberg, PO Hanisco, TF Jaegle, L Jacob, DJ Hintsa, EJ Lanzendorf, EJ Anderson, JG Gao, RS Keim, ER Donnelly, SG Del Negro, LA Fahey, DW McKeen, SA Salawitch, RJ Webster, CR May, RD Herman, RL Proffitt, MH Margitan, JJ Atlas, EL Schauffler, SM Flocke, F McElroy, CT Bui, TP AF Wennberg, PO Hanisco, TF Jaegle, L Jacob, DJ Hintsa, EJ Lanzendorf, EJ Anderson, JG Gao, RS Keim, ER Donnelly, SG Del Negro, LA Fahey, DW McKeen, SA Salawitch, RJ Webster, CR May, RD Herman, RL Proffitt, MH Margitan, JJ Atlas, EL Schauffler, SM Flocke, F McElroy, CT Bui, TP TI Hydrogen radicals, nitrogen radicals, and the production of O-3 in the upper troposphere SO SCIENCE LA English DT Article ID IN-SITU MEASUREMENTS; AIRCRAFT-BORNE; NASA ER-2; OH; OZONE; LASER; STRATOSPHERE; INTERFERENCE; ATMOSPHERE; CHEMISTRY AB The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O-3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O-3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O-3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about I part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O-3 than expected. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. ARQX, Atmospher Environm Serv, Downsview, ON M3H 5T4, Canada. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wennberg, PO (reprint author), CALTECH, Div Geol & Planetary Sci, 1200 E Calif Blvd, Pasadena, CA 91125 USA. RI Salawitch, Ross/B-4605-2009; Wennberg, Paul/A-5460-2012; Herman, Robert/H-9389-2012; Gao, Ru-Shan/H-7455-2013; McKeen, Stuart/H-9516-2013; Atlas, Elliot/J-8171-2015; Fahey, David/G-4499-2013 OI Salawitch, Ross/0000-0001-8597-5832; Herman, Robert/0000-0001-7063-6424; Fahey, David/0000-0003-1720-0634 NR 44 TC 260 Z9 264 U1 2 U2 47 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 2 PY 1998 VL 279 IS 5347 BP 49 EP 53 DI 10.1126/science.279.5347.49 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YP866 UT WOS:000071323900034 ER PT J AU Kippelen, B Marder, SR Hendrickx, E Maldonado, JL Guillemet, G Volodin, BL Steele, DD Enami, Y Sandalphon Yao, YJ Wang, JF Rockel, H Erskine, L Peyghambarian, N AF Kippelen, B Marder, SR Hendrickx, E Maldonado, JL Guillemet, G Volodin, BL Steele, DD Enami, Y Sandalphon Yao, YJ Wang, JF Rockel, H Erskine, L Peyghambarian, N TI Infrared photorefractive polymers and their applications for imaging SO SCIENCE LA English DT Article ID STATE; GAIN AB Photorefractive polymers with high diffraction efficiency in the visible and near-infrared regions of the electromagnetic spectrum have been developed, These polymers, which have a large dynamic range because of their high orientational birefringence, incorporate a dye designed to have a large dipole moment and a high linear polarizability anisotropy, Such polymers have enabled demonstrations of imaging through scattering media, using a holographic time-gating technique at a wavelength that is compatible with the transparency of biological tissues and with the emission of low-cost semiconductor laser diodes. C1 Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. CALTECH, Beckman Inst, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kippelen, B (reprint author), Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. RI Kippelen, Bernard/I-4058-2013; Enami, Yasufumi/E-4273-2016 OI Kippelen, Bernard/0000-0002-8417-7051; Enami, Yasufumi/0000-0002-0303-2695 NR 28 TC 219 Z9 225 U1 0 U2 20 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 2 PY 1998 VL 279 IS 5347 BP 54 EP 57 DI 10.1126/science.279.5347.54 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YP866 UT WOS:000071323900035 PM 9417020 ER PT B AU Das, S Tao, WK Johnson, D AF Das, S Tao, WK Johnson, D GP AMS AMS TI Response of a cloud microphysics parameterization in forecasting diurnal variation of cloudiness and precipitation SO 12TH CONFERENCE ON NUMERICAL WEATHER PREDICTION LA English DT Proceedings Paper CT 12th Conference on Numerical Weather Prediction CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc (AMS) C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Das, S (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 913, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 111 EP 112 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM02Q UT WOS:000077436900034 ER PT B AU Wiels, V Easterbrook, S AF Wiels, V Easterbrook, S GP IEEE COMP SOC IEEE COMP SOC TI Management of evolving specifications using category theory SO 13TH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 13th IEEE International Conference on Automated Software Engineering CY OCT 13-16, 1998 CL HONOLULU, HI SP IEEE Comp Soc, IEEE Comp Soc, Tech Council Software Engn, Cooperat R&D Agreement, USAF Res Lab Informat Directorate, NASA Ames Res Ctr, Microsoft Res, Inst Software Res, AAAI, ACM SIGART, SIGSOFT AB Structure is important in large specifications for understanding, testing and managing change. Category theory has been explored as framework for providing this structure, and has been successfully used to compose specifications. This work has typically adopted a "correct by construction" approach: components are specified, proved correct and then composed together in such a way to preserve their properties. However, in a large project, it is desirable to be able to mis specification and composition steps such that at any particular moment in the process, we may have established only some of the properties of the components, and some of the composition relations. In the's paper we propose adaptations to the categorical frame work in order to manage evolving specifications. We demonstrate the utility of the framework: on, the analysis of a port of a software change request for the Space Shuttle. C1 NASA, WVU Sofware Res Lab, Fairmont, WV 26554 USA. RP Wiels, V (reprint author), NASA, WVU Sofware Res Lab, 100 Univ Dr, Fairmont, WV 26554 USA. NR 0 TC 13 Z9 13 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-8186-8750-9 PY 1998 BP 12 EP 21 DI 10.1109/ASE.1998.732561 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BM17K UT WOS:000077906400002 ER PT B AU Van Baalen, J Robinson, P Lowry, M Pressburger, T AF Van Baalen, J Robinson, P Lowry, M Pressburger, T GP IEEE COMP SOC IEEE COMP SOC TI Explaining synthesized software SO 13TH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 13th IEEE International Conference on Automated Software Engineering CY OCT 13-16, 1998 CL HONOLULU, HI SP IEEE Comp Soc, IEEE Comp Soc, Tech Council Software Engn, Cooperat R&D Agreement, USAF Res Lab Informat Directorate, NASA Ames Res Ctr, Microsoft Res, Inst Software Res, AAAI, ACM SIGART, SIGSOFT AB Motivated by NASA's need for high-assurance software, NASA Ames' Amphion project has developed a generic program generation system based on deductive synthesis. Amphion has a number of advantages, such as the ability to develop a nw synthesis system simply by writing a declarative domain theory. However, as a practical matter, the validation of the domain theory for such a system is problematic because the link between generated programs and the domain theory is complex. As a result, when generated programs do not behave as expected, it is difficult to isolate the cause, whether it be an incorrect problem specification or an error in the domain theory. This paper describes a tool we are developing that provides formal traceability between specifications and generated code for deductive synthesis systems. It is based on extensive instrumentation of the refutation-based theorem prover used to synthesize programs. It takes augmented proof structures and abstracts them to provide explanations of the relation between a specification, a domain theory, and synthesized code. In generating these explanations, the tool exploits the structure of Amphion domain theories, so the end user is not confronted with the intricacies of raw proof traces. This tool is crucial for the validation of domain theories as well as being important in every-day use of the code synthesis system. It plays an important role in validation because when generated programs exhibit incorrect behavior, it provides the links that can be traced to identify errors in specifications or domain theory. It plays an important role in the every-day use of the synthesis system by explaining to users what parts of a specification or of the domain theory contribute to what pieces of a generated program. Comments are inserted into the synthesized code that document these explanations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Van Baalen, J (reprint author), NASA, Ames Res Ctr, MS 269-2,Code IC, Moffett Field, CA 94035 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-8186-8750-9 PY 1998 BP 240 EP 248 DI 10.1109/ASE.1998.732661 PG 9 WC Computer Science, Software Engineering SC Computer Science GA BM17K UT WOS:000077906400030 ER PT B AU Lowry, M Boyd, M Kulkarni, D AF Lowry, M Boyd, M Kulkarni, D GP IEEE COMP SOC IEEE COMP SOC TI Towards a theory for integration of mathematical verification and empirical testing SO 13TH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 13th IEEE International Conference on Automated Software Engineering CY OCT 13-16, 1998 CL HONOLULU, HI SP IEEE Comp Soc, IEEE Comp Soc, Tech Council Software Engn, Cooperat R&D Agreement, USAF Res Lab Informat Directorate, NASA Ames Res Ctr, Microsoft Res, Inst Software Res, AAAI, ACM SIGART, SIGSOFT AB From the viewpoint of a project manager responsible for the V&V of a software system, mathematical verification techniques provide a potentially valuable addition to otherwise standard empirical testing. However, the value they acid, both in terms of coverage and in fault detection, has been difficult to quantify. Potential cost savings fr om replacing resting with mathematical techniques cannot be realized until the tradeoffs can be quantified. This paper first describes a framework for a theory of software fault detection that is based on software reliability and formalized fault models. The novelty of this approach is that it takes into account the relative utility of the various fools for fault detection. Second, the paper then describes a utility model for integrating mathematical and empirical techniques with respect to fault detection and coverage analysis for software. Third the paper discusses how to determine the optimal combination of black-box testing, white-box (structural) testing, and formal methods in V&V of a software system. Finally, a demonstration of how this utility model can be used in practice is offered using a case study from a NASA software systems. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lowry, M (reprint author), NASA, Ames Res Ctr, MS 269-2,Code IC, Moffett Field, CA 94035 USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-8186-8750-9 PY 1998 BP 322 EP 331 DI 10.1109/ASE.1998.732690 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BM17K UT WOS:000077906400044 ER PT B AU Smith, GL AF Smith, GL GP AMS AMS TI Time-sampling errors of albedo from satellites SO 14TH CONFERENCE ON PROBABILITY AND STATISTICS IN THE ATMOSPHERIC SCIENCES LA English DT Proceedings Paper CT 14th Conference on Probability and Statistics in the Atmospheric Sciences CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc (AMS) AB An analysis is presented of the errors which are created when one computes the average value of the albedo of a region over a day or a month on the basis of restricted temporal sampling. The albedo of a region varies from day to day primarily due to changes of cloudiness. These albedo variations are autocorrelated in time and this autocorrelation can be approximated by an exponential. Diurnal variations of albedo are expressed using an empirical orthogonal function expansion in local time and location. Details of the temporal sampling are given by a sampling matrix which specifies the hour and day of each observation. An analytical expression is derived for the variance of the error of the computed daily and monthly mean albedo. This analysis can be used to compute the errors in albedo from existing satellite data sets or to evaluate the data products from future missions. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Smith, GL (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Mail Stop 420, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 20 EP 26 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM02N UT WOS:000077436200006 ER PT B AU Olson, JO Harris, CJ McGinnis, RS Dunkum, RC AF Olson, JO Harris, CJ McGinnis, RS Dunkum, RC GP AMER METEOROL SOC AMER METEOROL SOC TI An overview of the NASA Langley Research Center Earth Observing System (EOS) data and information system (EOSDIS) Tropical Rainfall Measurement Mission (TRMM) information system SO 14TH INTERNATIONAL CONFERENCE ON INTERACTIVE INFORMATION AND PROCESSING SYSTEM (IIPS) FOR METEOROLOGY, OCEANOGRAPHY, AND HYDROLOGY LA English DT Proceedings Paper CT 14th International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology at 78th AMS Annual Meeting CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc C1 NASA, Langley Res Ctr, Distributed Active Archive Ctr, Hampton, VA 23681 USA. RP Olson, JO (reprint author), NASA, Langley Res Ctr, Distributed Active Archive Ctr, Mail Stop 157D, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 31 EP 32 PG 2 WC Computer Science, Information Systems; Meteorology & Atmospheric Sciences SC Computer Science; Meteorology & Atmospheric Sciences GA BL80G UT WOS:000076779900009 ER PT B AU Zak, JA Rodgers, WG AF Zak, JA Rodgers, WG GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Observed changes in atmospheric boundary layer properties at Memphis International Airport during August 1995 SO 16TH CONFERENCE ON WEATHER ANALYSIS AND FORECASTING / SYMPOSIUM ON THE RESEARCH FOCI OF THE U.S. WEATHER RESEARCH PROGRAM LA English DT Proceedings Paper CT 16th Conference on Weather Analysis and Forecasting / Symposium on the Research Foci of the US Weather Research Program CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc RP Zak, JA (reprint author), NASA, Langley Res Ctr, R&D Field Off, FAA, M-S 250, Hampton, VA 23666 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 224 EP 226 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BL92Q UT WOS:000077162300078 ER PT B AU Bellue, DG AF Bellue, DG GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI SMG daily forecast verification, the next step SO 16TH CONFERENCE ON WEATHER ANALYSIS AND FORECASTING / SYMPOSIUM ON THE RESEARCH FOCI OF THE U.S. WEATHER RESEARCH PROGRAM LA English DT Proceedings Paper CT 16th Conference on Weather Analysis and Forecasting / Symposium on the Research Foci of the US Weather Research Program CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc C1 NASA, Lyndon B Johnson Space Ctr, NWS, Spaceflight Meteorol Grp, Houston, TX 77058 USA. RP Bellue, DG (reprint author), NASA, Lyndon B Johnson Space Ctr, NWS, Spaceflight Meteorol Grp, ZS8, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 431 EP 433 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BL92Q UT WOS:000077162300145 ER PT B AU Hubbard, GS Binder, AB Feldman, W AF Hubbard, GS Binder, AB Feldman, W BE Nalcioglu, O TI The Lunar Prospector Discovery mission: Mission and measurement description SO 1997 IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, VOLS 1 & 2 LA English DT Proceedings Paper CT 1997 IEEE Nuclear Science Symposium and Medical Imaging Conference CY NOV 09-15, 1997 CL ALBUQUERQUE, NM SP IEEE AB Lunar Prospector, the first competitively selected planetary mission in NASA's Discovery Program, will be described with emphasis on the radiation spectrometer instrumentation and anticipated scientific data return. Scheduled to be launched in January 1998, the mission will conduct a one year orbital survey of the Moon's composition and structure. The suite of five instruments will be outlined: neutron spectrometer, alpha particle spectrometer, gamma-ray spectrometer, electron reflectometer and magnetometer. Scientific requirements and measurement approach to detect water ice to a sensitivity of 50 ppm (hydrogen), measure key elemental constituents, detect radioactive gas release events and accurately map the Moon's gravitational and magnetic fields will be given. A brief overview of the programmatic accomplishments in meeting a tightly constrained schedule and budget is also provided. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hubbard, GS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4259-3 PY 1998 BP 22 EP 26 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Radiology, Nuclear Medicine & Medical Imaging SC Instruments & Instrumentation; Nuclear Science & Technology; Physics; Radiology, Nuclear Medicine & Medical Imaging GA BL13T UT WOS:000074401900006 ER PT B AU Peskov, V Ramsey, BD Fonte, P AF Peskov, V Ramsey, BD Fonte, P BE Nalcioglu, O TI Breakdown features of various microstrip-type gas counter designs and their improvements SO 1997 IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, VOLS 1 & 2 LA English DT Proceedings Paper CT 1997 IEEE Nuclear Science Symposium and Medical Imaging Conference CY NOV 09-15, 1997 CL ALBUQUERQUE, NM SP IEEE AB Breakdown mechanisms and spurious pulses, the precursors to some breakdowns, were studied experimentally for both uncoated and coated Microstrip Gas Counters (MSGC's) of different geometries, as well as for MicroGap Counters (MGC's) and for the "Compteur A Trou" (CAT). It was found that in all cases the breakdowns occurred through surface streamers, although the exact mechanism of streamer formation depended on the particular detector design. Based on these studies, new designs of microstrip detectors, in which the role of the substrate was minimized, were elaborated and tested. In some of these detectors, especially with large pitches (>2 mm), gains up to 2-3 x 10(5) were achieved together with good rate characteristics. The ultimate gain limit in all geometries was still set by spark-inducing streamers which appeared at some critical charge density in the avalanche. To avoid this, and particularly to enhance the performance of small-pitch MSGC's, preamplification structures can be used. Utilizing a parallel plate avalanche chamber as a front end to an MSGC resulted in an overall gain of similar to 10(6), limited in this case only by charge saturation. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Peskov, V (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4259-3 PY 1998 BP 291 EP 295 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Radiology, Nuclear Medicine & Medical Imaging SC Instruments & Instrumentation; Nuclear Science & Technology; Physics; Radiology, Nuclear Medicine & Medical Imaging GA BL13T UT WOS:000074401900061 ER PT B AU McMurray, RE Grimmer, MC Feldman, WC Hubbard, GS Zins, SD AF McMurray, RE Grimmer, MC Feldman, WC Hubbard, GS Zins, SD BE Nalcioglu, O TI Monte Carlo simulation of the gamma ray spectrometer performance on lunar prospector SO 1997 IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, VOLS 1 & 2 LA English DT Proceedings Paper CT 1997 IEEE Nuclear Science Symposium and Medical Imaging Conference CY NOV 09-15, 1997 CL ALBUQUERQUE, NM SP IEEE AB We present results of a simulation for the GRS instrument response expected in lunar orbit, using 90 spectral lines and a continuum gamma ray background taken from Apollo 15 and 16 data. The Monte Carlo program uses the exact dimensions and composition of the GRS in order to most accurately predict spectral performance, assuming an operating temperature on orbit of -30 degrees C. We expect to obtain a resolution at 662 keV @ -30 degrees C of about 9.6% FWHM. The data set is expected to be 2.5 to 8 times better in terms of peak intensity than the NaI data from Apollo orbiters. This factor depends on the gamma ray energy and is due to the high-Z EGO detector used in the GRS. Both coincidence and anticoincidence data will be returned, and a linear combination of the two spectra will be determined for best peak to background ratios. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP McMurray, RE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4259-3 PY 1998 BP 601 EP 604 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Radiology, Nuclear Medicine & Medical Imaging SC Instruments & Instrumentation; Nuclear Science & Technology; Physics; Radiology, Nuclear Medicine & Medical Imaging GA BL13T UT WOS:000074401900128 ER PT B AU Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T AF Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T BE Chan, KL Cheng, KS Singh, HP TI Mid-infrared observations of the Galactic bulge by the IRTS SO 1997 PACIFIC RIM CONFERENCE ON STELLAR ASTROPHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Pacific Rim Conference on Stellar Astrophysics CY AUG 13-16, 1997 CL HONG KONG, PEOPLES R CHINA SP Astrophys Soc Hong Kong, Hong Kong Polytech Univ, Hong Kong Univ Sci & Technol, KC Wong Educ Fdn, Lee Hysan Fdn, Univ Hong Kong AB Using the Mid-Infrared Spectrometer (MIRS) on board the Infrared Telescope in Space (IRTS) we obtained the 4.5 to 11.7 mu m spectra of the stellar populations and diffuse interstellar medium in the Galactic bulge (l approximate to 8.7 degrees, b approximate to 2.9, 4.0, 4.7, and 5.7 degrees). Below galactic latitudes of 4.0 degrees, the mid-infrared background spectra in the bulge are similar to the spectra of M & K giants. The UIR bands (6.2, 7.7, 8.6, and 11.3 mu m) are also detected in these regions and likely arise from the diffuse interstellar medium in the bulge. Above galactic latitudes of 4.0 degrees, the mid-infrared background spectra are similar to the spectrum of those evolved stars with high mass-loss rate detected by IRAS. One Likely interpretation is that this background emission arises predominantly from those stars with very low luminosities that have not been detected by IRAS. The main-sequence lifetime for such low-luminosity evolved stars is at least 10 Gyr, even in the metal poor cases. If these low-luminosity evolved stars are metal-rich, then the age would be much older. Thus, the existence of a large number (similar to 60) of such low-luminosity evolved stars in a small region (8' x 8') in the bulge would have a significant impact on our understanding of the stellar content and the age of the Galactic bulge. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chan, KW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-58-9 J9 ASTR SOC P PY 1998 VL 138 BP 37 EP 40 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74R UT WOS:000076547200007 ER PT B AU Hubeny, I AF Hubeny, I BE Chan, KL Cheng, KS Singh, HP TI Non-LTE line-blanketed model atmospheres of hot stars SO 1997 PACIFIC RIM CONFERENCE ON STELLAR ASTROPHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Pacific Rim Conference on Stellar Astrophysics CY AUG 13-16, 1997 CL HONG KONG, PEOPLES R CHINA SP Astrophys Soc Hong Kong, Hong Kong Polytech Univ, Hong Kong Univ Sci & Technol, KC Wong Educ Fdn, Lee Hysan Fdn, Univ Hong Kong AB A brief review of the recent developments in model atmospheres for hot stars is presented. We show that a significant progress in the fast numerical methods, and in producing new atomic data has led to an enormous improvement of the degree of realism in computed model atmospheres and predicted stellar spectra. The importance and the power of the new model atmospheres is illustrated on an analysis of HST/GHRS observations of the main-sequence O9 V star, 10 Lac. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hubeny, I (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-58-9 J9 ASTR SOC P PY 1998 VL 138 BP 139 EP 142 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74R UT WOS:000076547200027 ER PT B AU Hammoud, A Gerber, S Patterson, RL MacDonald, TL AF Hammoud, A Gerber, S Patterson, RL MacDonald, TL GP IEEE, DIELECT & INSULAT SOC IEEE, DIELECT & INSULAT SOC TI Performance of surface-mount ceramic and solid tantalum capacitors for cryogenic applications SO 1998 ANNUAL REPORT CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA, VOLS 1 AND 2 LA English DT Proceedings Paper CT 67th Annual Conference on Electrical Insulation and Dielectric Phenomena CY OCT 25-28, 1998 CL ATLANTA, GA SP IEEE, Dielect & Insulat Soc AB Low temperature electronics are of great interest for space exploration programs. These include missions to the outer planets, earth-orbiting and deep-space probes, remote-sensing and communication satellites. Terrestrial applications would also benefit from the availability of low temperature electronics. Power components capable of low temperature operation would, thus, enhance the technologies needed for the development of advanced power systems suitable for use in harsh environments. In this work, ceramic and solid tantalum capacitors were evaluated in terms of their dielectric properties as a function of temperature and at various frequencies. The surface-mount devices were characterized in terms of their capacitance stability and dissipation factor in the frequency range of 50Hz to 100kHz at temperatures ranging from mom temperature (20 degrees C) to about liquid nitrogen temperature (-190 degrees C). The results are discussed and conclusions made concerning the suitability of the capacitors investigated for low temperature applications. C1 NASA, Dynacs Engn Corp, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hammoud, A (reprint author), NASA, Dynacs Engn Corp, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5035-9 PY 1998 BP 572 EP 576 DI 10.1109/CEIDP.1998.732962 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA BM01M UT WOS:000077417300130 ER PT B AU Wang, RT Dick, GJ AF Wang, RT Dick, GJ BE Nelson, TL TI Cryo-cooled sapphire oscillator with ultra-high stability SO 1998 CONFERENCE ON PRECISION ELECTROMAGNETIC MEASUREMENTS DIGEST LA English DT Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp AB We present design details and test results for the first short-term frequency standard to achieve ultra-high stability (sigma(gamma) < 10(-14)) without the use of liquid helium. Technical features include vibration isolation by atmospheric helium gas and a new sapphire resonator design with adjustable compensation operating at 8-10K. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, RT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5018-9 PY 1998 BP 65 EP 66 DI 10.1109/CPEM.1998.699778 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics; Spectroscopy SC Engineering; Instruments & Instrumentation; Optics; Spectroscopy GA BL51B UT WOS:000075725900033 ER PT B AU Sandford, SP Antill, CW AF Sandford, SP Antill, CW BE Nelson, TL TI Frequency noise measurements of lasers locked to a rubidium mastered SO 1998 CONFERENCE ON PRECISION ELECTROMAGNETIC MEASUREMENTS DIGEST LA English DT Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp AB A small, evacuated, piezoelectrically-tuned Fabry-Perot cavity is stabilized using a commercial Rubidium oscillator. The cavity's resonance is measured and controlled using two diode-pumped Nd:YAG lasers; each locked to a mode of the cavity. Once controlled, the cavity resonance acts as a frequency reference for the lasers. To measure the laser frequency noise, one of the laser beams is combined with a laser beam from an identical system. The beat frequency between the two lasers allows a measure of the linewidth, frequency noise and root Allan variance of a single laser. This data is reported and compared to results from more elaborate laser frequency control schemes. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sandford, SP (reprint author), NASA, Langley Res Ctr, 5 N Dryden St M-S 468, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5018-9 PY 1998 BP 195 EP 196 DI 10.1109/CPEM.1998.699863 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics; Spectroscopy SC Engineering; Instruments & Instrumentation; Optics; Spectroscopy GA BL51B UT WOS:000075725900101 ER PT S AU Sterling, T Kogge, P AF Sterling, T Kogge, P GP IEEE TI New approaches to spaceborne computing SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB NASA's aggressive plans for extensive deep space exploration with a new generation of unmanned space craft requires a dramatic increase in responsibilities for onboard computing to reduce size, weight, and power to drastically reduce mission costs. No longer will all raw sensor data be transmitted back to Earth but rather only the results from extensive preprocessing to decrease total link capacity by one to three orders of magnitude. A new approach to on board data processing is necessitated by this new expanded mission requirement. Processor-In-Memory (PIM) architecture combines logic and memory on the same integrated circuit to permit direct access to memory row buffers, greatly increasing effective memory bandwidth, reducing overhead and latency, and improving power efficiency. Organizing and managing the resources of PIM based systems is challenging. The PIM-MT architecture is an innovative approach to harnessing the physical resources of PIM technology through a message driven multithreaded virtual execution model. This paper describes the concepts of PIM-MT and its role in future spaceborne computing. C1 CALTECH, Jet Prop Lab, High Performance Comp Syst Grp, Pasadena, CA 91109 USA. RP Sterling, T (reprint author), CALTECH, Jet Prop Lab, High Performance Comp Syst Grp, Mail Stop 168-522 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 23 EP 32 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600003 ER PT S AU Folta, DC Quinn, D AF Folta, DC Quinn, D GP IEEE TI A 3-D method for autonomously controlling multiple spacecraft orbits SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The need for innovative technical approaches for achieving and maintaining formations of spacecraft has come to the forefront as scientific objectives for Earth observation programs become more ambitious and spacecraft become more autonomous. The trend to develop small low-cost spacecraft has led many scientists to recognize the advantage of flying several spacecraft in formation to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single large platform. Yet, formation flying imposes additional complications on orbit maintenance, especially when each spacecraft has its own orbit requirements. Advances in automation and technology by the Goddard Space Flight Center (GSFC) allow the burden in maneuver planning and execution to be placed onboard the spacecraft, mitigating some of the associated operational concerns while increasing autonomy. This paper presents GSFC's Guidance, Navigation, and Control Center's (GNCC) 3-D operational control theory for formation maintenance of multiple Low Earth Orbit (LEO) spacecraft and an algorithm for formation flying of the low earth orbiting spacecraft that are part of the New Millennium Program (NMP). This system will be implemented as a closed-loop flight code onboard the NMP Earth Orbiter-1 (EO-1) spacecraft. This paper describes the orbital dynamics necessary to quantify proposed methods for the guidance and control of spacecraft required to fly in formation with either a reference spacecraft or a predicted orbit. Simulation results from an integrated autonomous ''fuzzy logic" control system called AutoCon(TM) are presented which use an autonomous closed-loop three-axis navigation control system. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Folta, DC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 51 EP 60 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600006 ER PT S AU Eisenman, AR Liebe, CC AF Eisenman, AR Liebe, CC GP IEEE TI The advancing state-of-the-art in second generation star trackers SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Until recently, only first-generation charge coupled device (CCD) spacecraft star trackers have been available. These track a small number of bright stars and are dependent on external processing for acquisition, calculation of corrections and transformation from CCD referenced to inertial referenced coordinates. Now, powerful microprocessors (>10 million instructions per second (MIPS)) with a few Mbytes of memory have become available in space qualified grades and have enabled the next step in star tracker concepts: second-generation fully autonomous designs. These second-generation units are equipped with star catalogs covering the entire sky. Their microprocessors instantly perform acquisition by pattern recognition of the entire image, thus relating the output from the star tracker directly to the celestial sphere. Their output data can be used in the attitude control system of a spacecraft without intermediate data processing. This saves central processor load, memory capacity and integratation of thousands of line of source code. The use of a large number of stars in each data frame makes the attitude estimates more accurate and operation both smoother and more robust in comparison to first-generation star trackers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Eisenman, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 111 EP 118 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600012 ER PT S AU Liebe, CC Dennison, EW Hancock, B Stirbl, RC Pain, B AF Liebe, CC Dennison, EW Hancock, B Stirbl, RC Pain, B GP IEEE TI Active Pixel Sensor (APS) based star tracker SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Charge-Coupled Device (CCD) based star trackers provide reliable attitude estimation onboard most 3 axis stabilized spacecraft. The spacecraft attitude is calculated based on observed positions of stars, which are located and identified in a CCD image of the sky. A new photon sensitive imaging array - Active Pixel Sensors (APS)- has emerged as a potential replacement to CCDs. The APS chips utilize existing Complementary Metal Oxide Semiconductor (CMOS) production facilities, and the technology has several advantages over CCD technology. These include: lower power consumption, higher dynamic range, higher blooming threshold, individual pixel readout, single 3.3 or 5 Volt operation, the capability to integrate on-chip timing, control, windowing, Analog to Digital (A/D) conversion and centroiding operations. However, because the photosensitivity of an APS pixel is non-homogeneous, its suitability as a star tracker imager has been unknown. This paper reports test results of a 256 x 256-pixel APS chip for star tracker applications. Using photon transfer curves, a system read-out noise of 7 electrons, under laboratory conditions, has been determined (photogate type). The full well of an APS pixel is determined to be around 450,000 electrons. Utilizing astronomical observations, the sensitivity of APS was measured to 13600 e(-)/(second.mm(2)) for a 0(th) magnitude star. Centroiding accuracy of the APS was in the order of 1/10 pixel. The dynamic range of the APS was better than 9 magnitudes. These measurements allow us to conclude that the APS is a potential replacement for CCD star trackers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 8 Z9 12 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 119 EP 127 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600013 ER PT S AU Christopher, DA Donet, C AF Christopher, DA Donet, C GP IEEE TI Flywheel technology and potential benefits for aerospace applications SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc DE energy storage; flywheel; power system AB An overview of advanced flywheel development for energy storage in aerospace applications is presented. The advantages offered by this emerging technology are reviewed and the major development challenges that need to be addressed are identified. The approach being used by the National Aeronautics and Space Administration (NASA) and United States Air Force (USAF) towards developing the technology is presented. C1 NASA, Lewis Res Ctr, Power & Propuls Flight Projects Off, Cleveland, OH 44135 USA. RP Christopher, DA (reprint author), NASA, Lewis Res Ctr, Power & Propuls Flight Projects Off, 21000 Brookpk Rd,Mail Stop 301-5, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 159 EP 166 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600017 ER PT S AU Castell, K Hernandez-Pellerano, A Wismer, M AF Castell, K Hernandez-Pellerano, A Wismer, M GP IEEE TI Closed loop software control of the MIDEX power system SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB MIDEX (Medium Class Explorer) is NASA's medium class series of scientific spacecraft. The MIDEX power system was designed to be adaptable to multiple missions, and will be used on the Microwave Anisotropy Probe (MAP), Earth Orbiter-1 (EO-1) and, with modifications, on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft. The power system design achieves its flexibility in part by containing mission unique modifications in software and firmware. Historically at Goddard Space Flight Center, the power system control loop was closed with analog hardware. In the MIDEX power system design, the outer system control loop is implemented with microprocessor based software. While the ease of adjustability in software allows the design to accommodate Low Earth Orbit (LEO), GEO (Geosynchronous Orbit) or Libration point ran sun missions, as well as any solar cell or battery technology, digital control poses a number of challenges. This paper describes the performance of the system's inner analog and outer digital control loops. A number of challenges were encountered in implementing Goddard's first spacecraft to use a digital power system control. These challenges and the solutions are addressed. C1 NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20771 USA. RP Castell, K (reprint author), NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 167 EP 175 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600018 ER PT S AU Ghaffarian, R AF Ghaffarian, R GP IEEE TI Assembly reliability of Ball Grid Array and Chip Scale Packages for high reliability applications SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Different aspects of advanced surface mount package technology have been investigated for aerospace applications. Three key areas included the assembly reliability of conventional Surface Mount, Ball Grid Arrays (BGAs), and Chip Scale Packages. Reliability of BGAs was assessed as part of a consortium effort led by the Jet Propulsion Laboratory. Nearly 200 test vehicles, each with four packages, were assembled and tested using an experiment design. The most critical variables incorporated in the experiment were package type, board material, surface finish, solder volume, and environmental conditions. The EGA test vehicles were subjected to thermal environments representative of aerospace applications. The test vehicles were monitored continuously to detect electrical failure and their failure mechanisms were characterized. A MicrotypeBGA consortium with industry-wide support was also organized to address technical issues regarding the interplay of package type, I/O counts, PWB (Printed Wiring Board) materials, and manufacturing variables on quality and reliability of board level assembly. This paper will present the most current thermal cycling test results (>4,000 cycles) for ceramic and plastic EGA packages as well as their failure mechanisms. The board level reliability of CSP assembly will also be reviewed and projected for a specific environmental condition. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Ghaffarian, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 359 EP 367 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600035 ER PT S AU Arakaki, G D'Agostino, S AF Arakaki, G D'Agostino, S GP IEEE TI New Millennium DS-2 electronic packaging smaller, faster with "managed" risk SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB New Millennium DS-2 is the second project of the New Millennium Program series, managed by the Jet Propulsion Laboratory (JPL). The project consists of a pair of probes, that will be carried by the Mars '98 spacecraft. After release from the Mars '98 Lander cruise stage, both probes will autonomously enter the atmosphere and penetrate into the Martian surface upon impact. After impact and penetration, a soil sample is taken and analyzed for the presence of water. In addition, other atmospheric and meteorological science is also performed during descent and after penetration. To create this small penetrator, several new technologies were chosen, including a modified Direct Chip Attach (DCA) packaging technology. This paper describes the development of the DS-2 DCA electronic packaging technology, particularly in the area of environmental protection, substrates, and interconnects. Additional topics include the collaboration between this development and NASA technology development programs, as well as follow-on developments for new programs at JPL. C1 CALTECH, Jet Prop Lab, Elect Packaging & Fabricat Sect, Pasadena, CA 91109 USA. RP Arakaki, G (reprint author), CALTECH, Jet Prop Lab, Elect Packaging & Fabricat Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 385 EP 392 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600038 ER PT S AU Tang, WC AF Tang, WC GP IEEE TI Micromechanical devices at JPL for space exploration SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Space exploration in the coming century will emphasize cost effectiveness and highly focused mission objectives, which will result in frequent multiple missions that broaden the scope of space science and to validate new technologies on a timely basis. Micro Electro Mechanical Systems (MEMS) is one of the key enabling technology to create cost-effective, ultra-miniaturized, robust, and functionally focused spacecraft for both robotic and human exploration programs. Examples of MEMS devices at various stages of development include microgyroscope, microseismometer, microhygrometer, quadrupole mass spectrometer, and micropropulsion engine. These devices, when proven successful, will serve as models for developing components and systems for new-millennium spacecraft. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Tang, WC (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, M-S 302-306,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-4311-5 J9 AEROSP CONF PROC PY 1998 BP 461 EP 470 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL20E UT WOS:000074664600046 ER PT B AU Whorton, MS Calise, AJ AF Whorton, MS Calise, AJ GP IEEE TI On-orbit model refinement for controller redesign SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB High performance control design for a flexible space structure is challenging since high fidelity plant models are difficult to obtain a priori. Uncertainty in the control design models typically require a very robust, low performance control design which must be tuned on-orbit to achieve the required performance. A new procedure for refining a multivariable open loop plant model based on closed-loop response data is presented. Using a minimal representation of the state space dynamics, a least squares prediction error method is employed to estimate the plant parameters. This control-relevant system identification procedure stresses the joint nature of the system identification and control design problem by seeking to obtain a model that minimizes the difference between the predicted and actual closed-loop performance. This paper presents an algorithm for iterative closed-loop system identification and controller redesign along with illustrative examples. C1 NASA, George C Marshall Space Flight Ctr, ED12 Precis Pointing Syst, Huntsville, AL 35812 USA. RP Whorton, MS (reprint author), NASA, George C Marshall Space Flight Ctr, ED12 Precis Pointing Syst, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 105 EP 116 PG 12 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900010 ER PT B AU Backes, PG Tso, KS Tharp, GK AF Backes, PG Tso, KS Tharp, GK GP IEEE TI The Mars Pathfinder mission Internet-based WITS rover planning and simulation system SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Web Interface for Telescience (WITS) is an Internet-based tool that the Mars Pathfinder mission used for both mission operations at JPL and public outreach. WITS enables the viewing of downlinked images and results in various ways, terrain feature measurement and annotation, and planning of daily mission activities. WITS is written in the Java language and is accessible by mission scientists and the general public via a web browser. The public can use WITS to plan and simulate their own rover missions. WITS will also be used in the planned 1998 lander and 2001 and 2003 rover missions to Mars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Backes, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 151 EP 157 PG 7 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900015 ER PT B AU Stolorz, P Roden, J Granat, R AF Stolorz, P Roden, J Granat, R GP IEEE TI Datamining as a foundation for science-enabling autonomy SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB In situ exploration by spacecraft and planetary revers will increasingly require knowledge "on demand" in the future as downlink constraints limit the amount of information that can be transmitted from these platforms back to earth. Several onboard processing methods have the potential to significantly enhance scientific results in these settings. They include automatic detection of natural satellites of planetary bodies, investigation of possible surface motions on planets and planetary moons, and directed acquisition of scientific data by planetary revers. The key ingredient in all three cases is the need to process scientific data directly onboard, so that information can be rapidly provided to an automated spacecraft executive and/or to ground-based Principal Investigators (PI's). We discuss here recent developments in data mining technology that were designed initially for ground-based scientific data analysis, We then outline how these ideas can be migrated to onboard platforms to dramatically enhance the scientific capabilities of autonomous spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stolorz, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 159 EP 164 PG 6 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900016 ER PT B AU Cromp, R AF Cromp, R GP IEEE TI Enabling knowledge on demand from remotely sensed imagery SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cromp, R (reprint author), NASA, Goddard Space Flight Ctr, Code 935, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 173 EP 186 PG 14 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900018 ER PT B AU Barnes, C Swift, G Johnston, A Rax, B LaBel, K AF Barnes, C Swift, G Johnston, A Rax, B LaBel, K GP IEEE TI Radiation effects considerations for the application of photonics in space systems SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB As civilian and military spacecraft continue to evolve, meeting performance demands will become particularly challenging because performance levels will be constrained by severe cost and weight restrictions. To meet these challenges, new technologies, such as photonics, will be employed that can provide desired performance levels within the framework dictated by these constraints. For the insertion of a new technology into a spacecraft to be successful, the radiation hardness assurance (RHA) of the technology must be established so that the mission is not jeopardized by exposure to the space radiation environment. In this paper we discuss the RHA issues associated with the infusion of photonics into space systems, both military and civilian. These issues will be contrasted with similar problems that have been encountered in the more traditional area of RHA for Si microcircuits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barnes, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 303-220, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 219 EP 239 PG 21 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900022 ER PT B AU Bernard, DE Dorais, GA Fry, C Gamble, EB Kanefsky, B Kurien, J Millar, W Muscettola, N Nayak, PP Pell, B Rajan, K Rouquette, N Smith, B Williams, BC AF Bernard, DE Dorais, GA Fry, C Gamble, EB Kanefsky, B Kurien, J Millar, W Muscettola, N Nayak, PP Pell, B Rajan, K Rouquette, N Smith, B Williams, BC GP IEEE TI Design of the remote agent experiment for spacecraft autonomy SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB This paper describes the Remote Agent flight experiment for spacecraft commanding and control. In the Remote Agent approach, the operational rules and constraints are encoded in the flight software. The software may be considered to be an autonomous "remote agent" of the spacecraft operators in the sense that the operators rely on the agent to achieve particular goals. The experiment will be executed during the flight of NASA's Deep Space One technology validation mission. During the experiment, the spacecraft will not be given the usual detailed sequence of commands to execute. Instead, the spacecraft will be given a list of goals to achieve during the experiment. In flight, the Remote Agent flight software will generate a plan to accomplish the goals and then execute the plan in a robust manner while keeping track of how well the plan is being accomplished. During plan execution, the Remote Agent stays on the lookout for any hardware faults that might require recovery actions or replanning. In addition to describing the design of the remote agent, this paper discusses technology-insertion challenges and the approach used in the Remote Agent approach to address these challenges. The experiment integrates several spacecraft autonomy technologies developed at NASA Ames and the Jet Propulsion Laboratory: on-board planning, a robust multithreaded executive, and model-based failure diagnosis and recovery. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bernard, DE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 259 EP 281 PG 23 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900024 ER PT B AU Reinholtz, K Patel, K AF Reinholtz, K Patel, K GP IEEE TI Testing autonomous systems for deep space exploration SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB NASA is moving into an era of increasing spacecraft autonomy. However, before autonomy can be routinely utilized, we must provide techniques for providing assurance that the system will perform correctly in flight. We describe why autonomous systems require advanced verification techniques, and offer some management and technical techniques for addressing the differences. Autonomous goal-driven spacecraft require advances in verification techniques because optimization (e.g. planning and scheduling) algorithms are at the core of much of autonomy. It is the nature of such algorithms that over much of the input space an intuitively "small" change in the input results in a correspondingly "small" change in the output: This type of response typically leads one to conclude, quite reasonably, that if the two responses are correct, those responses "between" them will probably be correct. However, there are certain regions in the input space where a "small" change in the input will result in a radically different output: One is not so inclined to conclude that all responses in these transition zones are likely to be correct. We believe, for two reasons, that these transition zones are one place where autonomous systems are likely to fail. First, boundary conditions, often a rich source of faults, are highly exercised in the transition zones, and so increase the likelihood of faults. Second, within the transition zone the algorithm outputs are likely to appear unusual, and, since the outputs of the algorithm become inputs to the remainder of the system, the whole system is probably pushed outside of its nominal usage profile: historically shown to be another good source of faults. We close with a discussion of risk management. Autonomous systems have many well-known management risk factors. Risk management and quality concerns must be pervasive, throughout all team members and the whole life-cycle of the project. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Reinholtz, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 303-310, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 283 EP 288 PG 6 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900025 ER PT B AU Pell, B Sawyer, SR Muscettola, N Smith, B Bernard, DE AF Pell, B Sawyer, SR Muscettola, N Smith, B Bernard, DE GP IEEE TI Mission operations with an autonomous agent SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Remote Agent (RA) is an Artificial Intelligence (AI) system which automates some of the tasks normally reserved for human mission operators and performs these tasks autonomously on-board the spacecraft. These tasks include activity generation, sequencing, spacecraft analysis, and failure recovery. The RA will be demonstrated as a flight experiment on Deep Space One (DS1), the first deep space mission of the NASA's New Millennium Program (NMP). As we moved from prototyping into actual flight code development and teamed with ground operators, we made several major extensions to the RA architecture to address the broader operational context in which RA would be used. These extensions support ground operators and the RA sharing a long-range mission profile with facilities for asynchronous ground updates; support ground operators monitoring and commanding the spacecraft at multiple levels of detail simultaneously; and enable ground operators to provide additional knowledge to the RA, such as parameter updates, model updates, and diagnostic information, without interfering with the activities of the RA or leaving the system in an inconsistent state. The resulting architecture supports incremental autonomy, in which a basic agent can be delivered early and then used in an increasingly autonomous manner over the lifetime of the mission It also supports variable autonomy, as it enables ground operators to benefit from autonomy when they want it but does not inhibit them from obtaining a detailed understanding and exercising tighter control when necessary. These issues are critical to the successful development and operation of autonomous spacecraft. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pell, B (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 289 EP 313 PG 25 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900026 ER PT B AU Aljabri, AS Bernard, DE Dvorak, DL Man, GK Pell, B Starbird, TW AF Aljabri, AS Bernard, DE Dvorak, DL Man, GK Pell, B Starbird, TW GP IEEE TI Infusion of autonomy technology into space missions: DS1 lessons learned SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The impact of infusing breakthrough autonomy technology into a flight project was a big surprise. Valuable technical and cultural lessons, many of general applicability when introducing system-level autonomy, have been learned by infusing the Remote Agent (RA) into NASA's Deep Space 1 (DS1) spacecraft. The RA's architecture embodies system-level autonomy in three major components: Planning and Scheduling, Execution, and Fault Diagnosis and Reconfiguration. Lessons learned include: The architecture was confirmed. Active participation by non-autonomy personnel in the development is essential. Communication of new concepts is essential, difficult, and hampered by differences in terminology. Giving a spacecraft system-level autonomy changes organizational roles in operating the spacecraft after launch, and hence changes roles during development. Software models supporting functions traditionally handled on the ground must be developed early enough to get on-board. Shortfalls in planned features must be technically and developmentally accomodatable, in particular not to threaten the launch schedule. Traditional commanding must be supported. Testing must be emphasized; end-to-end tests counter skepticism. These lessons and others, on incremental system releases and use of autocode generation, are based on 16 months of spiral development from start of project through the project's decision to reduce the role of the RA from full-time control of the spacecraft to a separable experiment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Aljabri, AS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 315 EP 329 PG 15 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900027 ER PT B AU Ryan, RE AF Ryan, RE GP IEEE TI Flight operations in the new millennium SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB New approaches are being studied for real-time interaction, and related supporting processes, with spacecraft and instruments in deep space. Spacecraft are evolving, improving in many ways, and generally becoming more robust. Operations is changing also. Operations will be more automated in the future. However, there is a challenge. Deep space missions are not all alike. The Operations phases of discovery and exploration are an extension of the research that creates the mission; they are the time of obtaining results. This document examines the historical role of flight operations, and its evolving processes, to develop an understanding of the operational methods that will be effective in the future. It takes people, equipment, software, space, and connectivity for Operations success. A balance has to be struck between improving technology, gaining knowledge, automation, and realistic expectations. Finally, the recommended methods to gain efficiency in Operations are system-wide services and shared resources. These common processes will meet the challenge of varied missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ryan, RE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 331 EP 336 PG 6 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900028 ER PT B AU Mishkin, AH Morrison, JC Nguyen, TT Stone, HW Cooper, BK Wilcox, BH AF Mishkin, AH Morrison, JC Nguyen, TT Stone, HW Cooper, BK Wilcox, BH GP IEEE TI Experiences with operations and autonomy of the Mars Pathfinder microrover SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Microrover Flight Experiment (MFEX) is a NASA OACT (Office of Advanced Concepts and Technology) flight experiment which, integrated with the Mars Pathfinder (MPF) lander and spacecraft system, landed on Mars on July 4, 1997. In the succeeding 30 sols (1 sol = 1 Martian day), the Sojourner microrover accomplished all of its primary and extended mission objectives. After completion of the originally planned extended mission, MFEX continued to conduct a series of technology experiments, deploy its alpha proton x-ray spectrometer (APXS) on rocks and soil, and image both terrain features and the lander. This mission was conducted under the constraints of a once-per-sol opportunity for command and telemetry transmissions between the lander and earth operators. As such, the MFEX rover was required to carry out its mission, including terrain navigation and contingency response, under supervised autonomous control. For example, goal locations were specified daily by human operators; the rover then safely traversed to these locations. During traverses, the rover autonomously detected and avoided rock, slope, and drop-off hazards, changing its path as needed before turning back towards its goal. This capability to operate in an unmodeled environment, choosing actions in response to sensor input to accomplish requested objectives, is unique among robotic space missions to date. This paper describes the techniques implemented on MFEX for operations and autonomous control; the performance of this vehicle on Mars is also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mishkin, AH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 2 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 337 EP 351 PG 15 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900029 ER PT B AU Bhaskaran, S Riedel, JE Synnott, SP AF Bhaskaran, S Riedel, JE Synnott, SP GP IEEE TI Autonomous nucleus tracking for comet/asteroid encounters: The STARDUST example SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB STARDUST is a mission to flyby the comet Wild-2 in early 2004 and return samples of the coma to Earth. During its 120-150 km flyby of the comet nucleus, a secondary science goal is to obtain images of the nucleus using the onboard navigation camera. Due to the 40 minute round-trip light time, ground processing of navigation data to update pointing information to maintain the nucleus in the camera field-of-view is impractical. Thus, a simple, reliable, and fast algorithm was developed to close the navigation loop onboard during encounter. The algorithm uses images of the nucleus during approach to update target relative state information. This involves centroiding on the image to obtain nucleus center-of-figure data and then processing the data through a Kalman filter to update the spacecraft position and attitude. Monte Carlo simulations were then performed to test the algorithm. These simulations incorporated errors in spacecraft initial position and in attitude knowlede to provide a "truth" model which the filter must recover from. The results of the simulations proved that the algorithm was successful in maintaining the nucleus in the camera field-of-view assuming nominal values for the error sources. Even with worst case errors, the algorithm performed successfully in over 90% of the cases. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bhaskaran, S (reprint author), CALTECH, Jet Prop Lab, MS 301-150,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 3 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 353 EP 365 PG 13 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900030 ER PT B AU Price, HW Clark, KB Guiar, CN Ludwinski, JM Smyth, DE AF Price, HW Clark, KB Guiar, CN Ludwinski, JM Smyth, DE GP IEEE TI X2000 flight missions utilizing common modular components SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The X2000 First Delivery engineering model advanced technology spacecraft bus is being developed at NASA's Jet Propulsion Laboratory to enable a challenging and diverse set of interplanetary missions in the first few years of the 21st century. These missions were examined in detail, and a consolidated set of requirements was synthesized to guide the design of the first X2000 bus. A software and hardware architecture was developed for the X2000 bus that is modular, scaleable, and upgradable. It will enable the procurement of highly capable, low mass flight systems that can perform the mission set at a low recurring cost for the X2000 bus or components of the bus used for each mission. An end-to-end integrated Mission Data System is also being developed as part of the X2000 First Delivery to enable more flexible mission operations. A high degree of onboard autonomy is planned to lower the staffing and cost of operations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Price, HW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 369 EP 381 PG 13 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900031 ER PT B AU Gat, E Pell, B AF Gat, E Pell, B GP IEEE TI Abstract resource management in an unconstrained plan execution system SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB We describe the abstract resource management mechanism in ESL (Execution Support Language [4]). ESL is the implementation substrate for the New Millennium Remote Agent Smart Executive [10], part of a NASA program to demonstrate autonomous control of an unmanned spacecraft scheduled to launch in 1998 [1]. The executive is responsible for robust plan execution in the face of unexpected run-time contingencies. Part of this task requires run-time management of the spacecraft's configuration, whose component states are modeled as abstract resources. In this paper we describe the ESL constructs for managing these abstract resources. The resource management facilities in ESL are similar to the constraint management constructs in RAPs [3]. The major contribution in this paper is the implementation of these facilities in an unconstrained execution substrate implemented as an extension to a standard programming language (in this case, Common Lisp) rather than within a constrained self-contained plan execution language. This turns out to significantly simplify complex programming tasks. The main technical problem in a resource management system is designing a representation that allows automatic determination of when conflicts exist. In its full generality this becomes a full-blown planning problem, and therefore an impractical strategy for a reactive executive. Instead, we model abstract resources as properties, logical assertions whose final values are guaranteed unique. When two properties are identical but for their final value then they are in conflict. This paper describes the ESL constructs and mechanisms for scheduling tasks so that they do not attempt to achieve conflicting properties simultaneously, and for invoking external recovery mechanisms for restoring properties to their desired states when forced away from those states by unexpected contingencies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gat, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 525-3660, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 383 EP 390 PG 8 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900032 ER PT B AU Housner, J AF Housner, J GP IEEE TI Rapid modeling, assembly and simulation in design SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB A next generation rapid modeling, assembly and simulation design system is introduced. The design system utilizes smart component product models and smart tools. The concepts of the system, the smart models and the smart tools are discussed with succinct mathematical formulation where appropriate. Examples which demonstrate the unique features of the system and its value are provided. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Housner, J (reprint author), NASA, Langley Res Ctr, Mail Stop 240, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 447 EP 455 PG 9 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900038 ER PT B AU Noor, AK Venneri, SL AF Noor, AK Venneri, SL GP IEEE TI ISE - Intelligent Synthesis Environment for future aerospace systems SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Intelligent Synthesis Environment (ISE) being developed by NASA, UVA and JPL for significantly enhancing the rapid creation of innovative affordable products and missions is described. ISE uses a synergistic combination of leading-edge technologies, including high-performance computing, high-capacity communications and networking, virtual product development, knowledge-based engineering, computational intelligence, human-computer interaction, and product information management. The environment will link scientists, design teams, manufacturers, suppliers and consultants who participate in the mission synthesis, as well as in the creation and operation of the aerospace system. It will radically advance the process by which complex science missions are synthesized, and high-tech engineering systems are designed, manufactured and operated. The evolution of engineering design is described along with the shortcomings of current product development techniques. The need for ISE to create high-science payoff missions and aerospace systems at affordable costs is discussed. The five major components critical to ISE and some of their subelements are described; namely, human-ISE interaction; infrastructure for distributed collaboration; rapid synthesis and simulation tools; intelligent life-cycle system integration; and cultural change in the creative process. Related government and industry programs are outlined and future impact of ISE on complex missions and aerospace systems is discussed. C1 Univ Virginia, Ctr Adv Computat Technol, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, Ctr Adv Computat Technol, NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 467 EP 486 PG 20 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900040 ER PT B AU Lamarra, N Dunphy, J AF Lamarra, N Dunphy, J GP IEEE TI Interactive sharable environment for collaborative spacecraft design SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB An advanced integrated environment is being developed at JPL that links collaborators who wish to perform interactive design analyses and/or mission simulations. The environment utilizes commercial technology (such as 3D visualization) where applicable, but key pieces are currently provided by software developed in-house for user interaction and spacecraft modeling. It allows a mission scenario to be built and exercised at various levels (e.g., macro or micro simulation, modeling or analysis), and integrates existing tools preferred by participants "in-place". Mission information (e.g., target body, space environment), spacecraft information (e.g., drawings, structures), and payload information (e.g., subsystem or instrument models) are connected into a simulation which can be run from within an immersive sharable environment. This allows interaction of the users with components of particular interest to each while others can view the "big picture" results of the interactions, and make recommendations such as parameter trades or component alternatives. Components of this environment are currently being developed by several NASA centers who wish to leverage each other's strengths, and a shared information infrastructure facilitates the connections (e.g., access to databases of designs, products, models and data). We believe that the collaborative process is most successful when the participants can immediately see the collective results of their separate inputs, therefore our goal was to facilitate real-time collaborative interactivity. We will discuss the problems and achievements from early utilization of this evolving interactive environment, and describe the near-term plans for shared development and deployment of the collaborative capabilities across NASA. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lamarra, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 525-3682, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 487 EP 496 PG 10 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900041 ER PT B AU Hinton, DE Nolt, IG Park, JH Smith, WL Abrams, MC AF Hinton, DE Nolt, IG Park, JH Smith, WL Abrams, MC GP IEEE TI Applications of advanced technologies to space-based Fourier transform spectrometers for atmospheric remote sensing SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB A design for a miniaturized high resolution Fourier transform spectrometer (FTS) system for space based applications is proposed which will combine new advanced technologies and the proven advantages of the FTS to deliver a new class of remote sensing instruments with more than an order of magnitude reduction in mass, volume, power, and telemetry rate relative to existing instrumentation. For instance, the new design will have a volume of similar to 0.25 m(3), mass of 20-25 kg, and power of 50 watts, compared with the successful Shuttla-borne Atmospheric Trace Molecule Spectroscopy (ATMOS) FTS with similar to 1 m(3), 250 kg, and 200 watts. This development is founded on recent advances in materials for lightweight stable structures, materials with piezoelectric properties, detectors, electronics, on-board digital signal processing, and miniature, frequency-stable lasers. Together these advances address all the major elements of an FTS that dictate the instrument volume and mass and will enable the development of revolutionary instrumentation for scientific missions in space. The new FTS can operate in emission mode in the infrared region, and also in absorption mode in the infrared and visible regions, enabling wide application in variety of remote sensing of the Earth's atmosphere for the study of meteorology, atmospheric chemistry and circulation, and climate change, and planetary exploration. The design study is currently in progress under the NASA's New Millennium Program. The design concept and potential application for space programs in the years 2000 and beyond will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hinton, DE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 499 EP 504 PG 6 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900042 ER PT B AU Hubbard, GS AF Hubbard, GS GP IEEE TI Lunar prospector: Developing a very low cost planetary mission SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Lunar Prospector, the first competitively selected planetary mission in NASA's Discovery Program, will be described with emphasis on the lessons learned from managing a very low cost project. Insights into government-industry teaming, project management, contractual arrangements, schedule and budget reserve approach will be discussed. Scheduled to be launched in early 1998, the mission will conduct a one year orbital survey of the Moon's composition and structure. A mission overview and scientific data return will be briefly described in the context of low cost mission development. The suite of five instruments will be outlined: Neutron Spectrometer (NS), Alpha Particle Spectrometer (APS), Gamma Ray Spectrometer (GRS), Magnetometer (MAG) and an Electron Reflectometer (ER). Scientific requirements and measurement approach to detect water ice to a sensitivity of 50 ppm (hydrogen), measure key elemental constituents, detect gas release events and accurately map the Moon's gravitational and magnetic fields will be described. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hubbard, GS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 505 EP 515 PG 11 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BL20F UT WOS:000074664900043 ER PT B AU Fukunaga, A Hayworth, K Stoica, A AF Fukunaga, A Hayworth, K Stoica, A GP IEEE TI Evolvable hardware for spacecraft autonomy SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Evolvable hardware is a recently proposed technology in which reconfigurable hardware under the control of an evolutionary (genetic) algorithm can automatically self-reconfigure into configurations with the desired behavior. This would not only enable the on-demand generation of new functionality when needed, but this could provide increased fault-tolerance, as the hardware would be able to cope with faults by reassigning function cells to take over the faulty ones. This paper describes ongoing work at JPL, focusing on applications to onboard image processing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fukunaga, A (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 IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 135 EP 143 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000013 ER PT B AU Sherwood, R Govindjee, A Yan, D Rabideau, G Chien, S Fukunaga, A AF Sherwood, R Govindjee, A Yan, D Rabideau, G Chien, S Fukunaga, A GP IEEE TI Using ASPEN to automate EO-1 activity planning SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB This paper describes the application of an automated planning and scheduling system to the NASA Earth Orbiting 1 (EO-1) mission. The planning system, ASPEN, is used to autonomously schedule the daily activities of the satellite. The satellite and operations constraints are encoded within a software model used by the planner. This paper includes a description of the planning system and the associated modeling language. We then discuss how we encoded the EO-1 spacecraft operations with the modeling language. We conclude with a description of the end-to-end planning system as we envision it for EO-1. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sherwood, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 145 EP 152 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000014 ER PT B AU Fisher, F Chien, S Paal, L Law, E Golshan, N Stockett, M AF Fisher, F Chien, S Paal, L Law, E Golshan, N Stockett, M GP IEEE TI An automated deep space communications station SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB This paper describes an architecture being implemented for an autonomous Deep Space Tracking Station(DS-T). The architecture targets fully automated routine operations encompassing scheduling and resource allocation, antenna and receiver predict generation, track procedure generation from service requests, and closed loop control and error recovery for the station subsystems. This architecture is being validated by construction of a prototype DS-T station which will be demonstrated in two phases: down-link (March 98) and up-link/down-link(July 98). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fisher, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 153 EP 162 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000015 ER PT B AU Bauer, FH Hartman, K Lightsey, EG AF Bauer, FH Hartman, K Lightsey, EG GP IEEE TI Spaceborne GPS current status and future visions SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Global Positioning System (GPS), developed by the Department of Defense, is quickly revolutionizing the architecture of future spacecraft and spacecraft systems. Significant savings in spacecraft life cycle cost, in power, and in mass can be realized by exploiting Global Positioning System (GPS) technology in spaceborne vehicles. These savings are realized because GPS is a systems sensor-it combines the ability to sense space vehicle trajectory, attitude, time, and relative ranging between vehicles into one package. As a result, a reduced spacecraft sensor complement can be employed on spacecraft and significant reductions in space vehicle operations cost can be realized through enhanced onboard autonomy. This paper provides an overview of the current status of spaceborne GPS, a description of spaceborne GPS receivers available now and in the near future, a description of the 1997-1999 GPS flight experiments and the spaceborne GPS team's vision for the future. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bauer, FH (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 195 EP 208 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000018 ER PT B AU Imbriale, WA AF Imbriale, WA GP IEEE TI Evolution of the deep space network 34-m diameter antennas SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The principal responsibilities of the NASA Deep Space Network (DSN) are to support unmanned interplanetary spacecraft missions and to support radio and radar astronomy observations in the exploration of the solar system and the universe. At each of the three complexes there are multiple large parabolic dish antennas equipped with ultra sensitive receiving systems. This report details the evolution of the design of the 34-meter diameter antennas. The design is traced from its initial 26-meter operation at L-band (960 MHz) though the present 34-meter beamwaveguide designs that support S-band(2 GHz),X-band(8 GHz)and Ka-band(32-GHz). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Imbriale, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 403 EP 430 PG 28 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000041 ER PT B AU Rochblatt, DJ AF Rochblatt, DJ GP IEEE TI Holographic measurements of the NASA-JPL deep space network antennas SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL. 3 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Microwave holography, as applied to reflector antennas, is a technique which utilizes the Fourier Transform relation between the complex far-field radiation pattern of an antenna and the complex aperture distribution. Resulting aperture phase and amplitude distribution data are used to precisely characterize various crucial performance parameters, including panel alignment, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation effects. The holography technique provides a methodology for analysis, evaluation, and RF performance improvement of large reflector and beam waveguide antennas. Strong CW signals obtained from geostationary sources are used as far-field sources. Microwave holography has been one of the most economical techniques for increasing the performance of the large DSN antennas in terms of cost-to-performance ratio. This paper describes the application of the holography technique as applied at the NASA-JPL Deep Space Network (DSN) antennas with an emphasis on the 34-M beamwaveguide (BWG) subnet, successfully preparing them for operation at Ka-band (32 GHz). A table summarizing the holography historical data is also included. Recent results in which we aligned the panels of the three 34-M BWG antennas (DSS-24, DSS-25 and DSS-26) to an rms surface precision of 0.25 mm is described. The precision of these antennas (diameter/rms) is 1.36x10(5) and their gain limit is at 95 GHz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rochblatt, DJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 441 EP 452 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing SC Engineering; Remote Sensing GA BL20G UT WOS:000074665000043 ER PT B AU Crawford, JA Mobarry, CM AF Crawford, JA Mobarry, CM GP IEEE TI HRUNTING: A distributed shared memory system for the BEOWULF parallel workstation SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Shared memory programming systems present a helpful abstraction to the parallel programmer. However, modern commodity and near commodity architectures, such as Networks-of-Workstations (IBM SP/2) and Piles-of-PCs (Beowulf) lack hardware support for memory operations that span multiple memory busses. Such architectures require software support for shared memory operations. Two important design choices by which software shared memory can be characterized are namespace model and access method. In order to provide the sematics and ease-of-use of shared memory multiprocessors, distributed memory systems must. provide a global namespace and a transparent (implicit) access method. This paper describes Hrunting, a freeware distributed shared memory (DSM) system for Beowulf-class multicomputers that satisfies both requirements. In order to reduce network communications, the DSM system uses the release consistency model. Release consistency does not guarantee that writes to shared memory by one process will be visible to another process until the processes have synchronized, thus allowing communications between the processes to be delayed or eliminated. It has been shown that release consistency is equivalent to serial consistency with sufficient synchronization. In order to take advantage of the existing memory management hardware and software, the DSM system deals with the shared memory on the granularity of virtual memory pages. The DSM system employs a multiple writer protocol to allow several processes to write to different parts of the same virtual memory page, and an invalidate protocol to allow processes to keep copies of shared pages until the pages are modified. The performance of the DSM system was tested with a Barnes-Hut N-body galaxy simulation and with a parallel sort using the Parallel Sorting by Regular sampling (PSRS) algorithm. The testing platform was a cluster of 16100 MHz Pentiums connected by a full-duplex 100 Mbit/s Ethernet switch. The sort scaled well up to 8 nodes, but achieved only a 50% efficiency on 15 nodes. The Barnes-Hut code, however, acheived a parallel efficiency of 95% with 15 nodes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crawford, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 337 EP 344 PG 8 WC Engineering, Aerospace; Computer Science, Information Systems; Computer Science, Software Engineering; Telecommunications SC Engineering; Computer Science; Telecommunications GA BL20H UT WOS:000074665100029 ER PT B AU Sterling, T Cwik, T Becker, D Salmon, J Warren, M Nitzberg, B AF Sterling, T Cwik, T Becker, D Salmon, J Warren, M Nitzberg, B GP IEEE TI An assessment of Beowulf-class computing for NASA requirements: Initial findings from the first NASA workshop on Beowulf-class clustered computing SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Beowulf class of parallel computing machine started as a small research project at NASA Goddard Space Flight Center's Center of Excellence in Space Data and Information Sciences (CESDIS). From that work evolved a new class of scalable machine comprised of mass market common off-the-shelf components ((MCOTS)-C-2) using a freely available operating system and industry-standard software packages. A Beowulf-class system provides extraordinary benefits in price-performance. Beowulf-class systems are in place and doing real work at several NASA research centers, are supporting NASA-funded academic research, and operating at DOE and NIH. The NASA user community conducted an intense two-day workshop in Pasadena, California on October 22-23, 1997. This first workshop on Beowulf-class systems consisted primarily of technical discussions to establish the scope of opportunities, challenges, current research activities, and directions for NASA computing employing Beowulf-class systems. The technical discussions ranged from application research to programming methodologies. This paper provides an overview of the findings and conclusions of the workshop. The workshop determined that Beowulf-class systems can deliver multi-Gflops performance at unprecedented price-performance but that software environments were not fully functional or robust, especially for larger "dreadnought"-scale systems. It is recommended that the Beowulf community engage in an activity to integrate, port, or develop, where appropriate, necessary components of the software infrastructure to fully realize the potential of Beowulf-class computing to meet NASA and other agency computing requirements. C1 NASA, Jet Prop Lab, CALTECH, Pasadena, CA 91125 USA. RP Sterling, T (reprint author), NASA, Jet Prop Lab, CALTECH, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 367 EP 381 PG 15 WC Engineering, Aerospace; Computer Science, Information Systems; Computer Science, Software Engineering; Telecommunications SC Engineering; Computer Science; Telecommunications GA BL20H UT WOS:000074665100032 ER PT B AU LaBel, KA Marshall, CJ Marshall, PW Luers, PJ Reed, RA Ott, MN Seidleck, CM Andrucyk, DJ AF LaBel, KA Marshall, CJ Marshall, PW Luers, PJ Reed, RA Ott, MN Seidleck, CM Andrucyk, DJ GP IEEE TI On the suitability of fiber optic data links in the space radiation environment: A historical and scaling technology perspective SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB As NASA, DoD, industry, and others propagate the current spacecraft trends for increasing science data throughput and on-board processing, the use of fiber optic data links between spacecraft subsystems has gained heightened interest. With this in mind, we present a perspective of the use of these fiber optic systems in the space radiation environment that encompasses both the historical past and scaleable future space systems and their requirements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP LaBel, KA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 421 EP 434 PG 14 WC Engineering, Aerospace; Computer Science, Information Systems; Computer Science, Software Engineering; Telecommunications SC Engineering; Computer Science; Telecommunications GA BL20H UT WOS:000074665100034 ER PT B AU Morakis, JC Miller, W AF Morakis, JC Miller, W GP IEEE TI A comparison of modified convolutional codes with sequential decoding and turbo codes SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB In an effort to achieve bandwidth efficient but reliable communications at lower signal-to-noise ratios, NASA is evaluating its presently developed coding techniques by conducting simulations and tests. These tests will form a basis for comparison of these systems and some newly proposed systems for NASA's coding standards. NASA's present coding standards support convolutional inner codes and Reed-Solomon outer codes. Simulations of coding techniques under development indicate that some variation of convolutional codes with sequential decoding achieve a performance close to that of turbo codes. Compared to the turbo codes these convolutional codes offer advantages in computational complexity and other aspects such as free and open architectures. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Morakis, JC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 435 EP 439 PG 5 WC Engineering, Aerospace; Computer Science, Information Systems; Computer Science, Software Engineering; Telecommunications SC Engineering; Computer Science; Telecommunications GA BL20H UT WOS:000074665100035 ER PT B AU Cook, R AF Cook, R GP IEEE TI Mars Pathfinder mission operations: Faster, better, cheaper on Mars SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB On July 4, 1997, the Mars Pathfinder spacecraft landed successfully in Ares Vallis, Mars. The following days and weeks were a whirlwind of scientific and technological achievement, as the lander and rover met and exceeded all of the mission objectives. This accomplishment is clear evidence that the faster, better, cheaper implementation approach can result in highly successful and low cost missions. A number of innovative design, fabrication, and management techniques were used to build and launch the spacecraft within the cost cap. The same faster, better, cheaper spirit was also applied to develop the mission operations system and conduct operations through cruise and surface operations. The highly operable designs of the Flight System and Ground Data System enabled an operations architecture in which most activities were performed by a core group of functional generalists. This group consisted of experienced development and test personnel whose skills were augmented with cross-training and contingency testing. The small size of this team combined with a flat management structure permitted highly streamlined and efficient operational processes. This efficiency was critical during the surface mission when daily updates to the operations plan were performed. C1 CALTECH, Jet Prop Lab, Mars Pathfinder Project, Pasadena, CA 91109 USA. RP Cook, R (reprint author), CALTECH, Jet Prop Lab, Mars Pathfinder Project, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 413 EP 420 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200038 ER PT B AU Day, RM AF Day, RM GP IEEE TI Leadership of fast track projects SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Fast track missions require leadership above all else. Leadership is manifested in vision and commitment. The vision must be communicated by the project leadership and adopted by all members of the team including suppliers. Thorough planning, organization, implementation and control are essential leadership skills. An effective risk management process is key to survival in today's cost constrained environment. Well thought out mission descope plans with clearly defined minimum performance floors and firm trigger points are required to execute programs within constrained resources Close communication and appreciation of customers and suppliers are critical to the success of all missions and particularly fast track missions. A shared vision and mutual respect between the customer and project manager are necessary to execute missions on fast timetables without distraction. On-time deliveries of quality products are far from guaranteed regardless of program requirements or mission importance. A late component delivery or environmental test failure can bring a fast track schedule to a halt. Successful integration of customers and suppliers into the project team requires establishing project values and communication norms at the outset and maintaining them for the life of the mission. The Microwave Anisotropy Probe (MAP) is an eagerly awaited and potentially historic NASA space science mission. MAP is on the leading edge of the newest generation of Explorer missions that trace a long and distinguished lineage of over 70 successful missions since 1958. The MAP mission presents an increasingly common management and design challenge. How does one implement a top ranked science mission with an aggressive schedule and firm cost cap? Can you really achieve all three: better, cheaper and faster? This paper discusses these conflicting priorities and some new and some not-so-new mission management principles employed on MAP to ensure the technical and programmatic success of the mission. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Day, RM (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 410-2, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 433 EP 442 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200040 ER PT B AU Dallas, SS AF Dallas, SS GP IEEE TI Space interferometry mission SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Space Interferometry Mission (SLM) flight system will be launched in June of 2005 into a nearly circular orbit around the Earth. A Delta II 7920 launch vehicle will boost the SIM flight system from the Vandenberg Air Force Base into Earth orbit. Over the nest three months, the flight system will be calibrated and prepared for the science observation phase. During the science observation phase, data will be collected and returned from a precision optical interferometer on-board the spacecraft for five years and will enable fundamental new discoveries in both galactic and extra-galactic astronomy. SIM will perform unparalleled wide-angle astrometry with an angular accuracy of at least 4 microarcsecs (mu as), roughly a factor of 250 over the current state of the art, and narrow-angle astrometry with an angular accuracy of 0.6-1 mu as. This precision enables the measurement of distances to sufficiently bright objects in the galaxy by direct parallax with no more than 10% error and makes possible highly accurate proper motion measurements of objects. As a consequence, SIM will allow studies of the kinematics of both isolated stars and composite systems over a large fraction of our galaxy and of large-scale transverse motions out to 100 Megaparsecs (Mpc). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dallas, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 443 EP 456 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200041 ER PT B AU Clawson, JF AF Clawson, JF GP IEEE TI Mars Pathfinder "common sense" Mission Assurance SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB The Mars Pathfinder Mission Assurance program was the first "tailored" approach at JPL. It featured flexibility, common sense, concurrent engineering, and lower cost. Documentation was cut significantly, MA team members were empowered, a full environmental test program was implemented, selective redundancy was employed, QA was based on processes (not historical points), and the electronic parts program was a mixture of Cassini common buys and Military grades. The MA cost was less than one-third of tradition and the number of Problem/Failure reports was less than one-quarter normal(at one-third the normal closure cost each). There were no significant deviations from the plan created over three years before launch. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clawson, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 477 EP 489 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200044 ER PT B AU Clark, KP AF Clark, KP GP IEEE TI Mars global surveyor mission assurance: Key approaches for faster, better, cheaper missions SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB Future space missions are required to deliver significant results with new technology and substantially reduced development cost and schedule. Among the first of the recent Faster, Better, Cheaper (FBC) missions for Jet Propulsion Laboratory (JPL), the National Aeronautics and Space Administration's (NASA's) Mars Global Surveyor (MGS) was launched to Mars on November 7, 1996 after spending $148M and 27 months in development. A phoenix risen from the ashes of Mars Observer (MO), MGS combined significant heritage with key enabling new technologies to meet its ambitious programmatic and technical goals. This development was characterized by significant teaming between JPL and its development partners. The MGS mission assurance (MA) program was tailored from its MO baseline to capitalize on previous heritage, use development partners' assurance approaches, balance technical risk and implement new assurance approaches consistent with the significant development constraints. The key approaches included teaming, heritage, personnel consistency, concurrency, collocation, task value analysis, communication, peer review, rapid closure, appropriate attention to detail and education. This paper will outline the MGS mission assurance requirements and describe the key mission assurance approaches. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clark, KP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-200, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 491 EP 506 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200045 ER PT B AU Ruffa, JA Castell, K Flatley, T Lin, M AF Ruffa, JA Castell, K Flatley, T Lin, M GP IEEE TI MIDEX advanced modular and distributed spacecraft avionics architecture SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB MIDEX (Medium Class Explorer) is the newest line in NASA's Explorer spacecraft development program. As part of the MIDEX charter, the MIDEX spacecraft development team has developed a new modular, distributed, and scaleable spacecraft architecture that pioneers new spaceflight technologies and implementation approaches, all designed to reduce overall spacecraft cost while increasing overall functional capability. This resultant "plug and play" system dramatically decreases the complexity and duration of spacecraft integration and test, providing a basic framework that supports spacecraft modularity and scalability for missions of varying size and complexity. Together, these subsystems form a modular, flexible avionics suite that can be modified and expanded to support low-end and very high-end mission requirements with a minimum of redesign, as well as allowing a smooth, continuous infusion of new technologies as they are developed without redesigning the system. This overall approach has the net benefit of allowing a greater portion of the overall mission budget to be allocated to mission science instead of a spacecraft bus. The MIDEX scaleable architecture is currently being manufactured and tested for use on the Microwave Anisotropy Probe (MAP), an inhouse program at GSFC. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ruffa, JA (reprint author), NASA, Goddard Space Flight Ctr, Code 735, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 531 EP 541 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200048 ER PT B AU Kahn, P Yu, J AF Kahn, P Yu, J GP IEEE TI Space interferometry mission: New system engineering approaches, tools, models and testbeds SO 1998 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 5 LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 21-28, 1998 CL ASPEN, CO SP IEEE, Aerosp & Electr Syst Soc AB In 2005, NASA's Origins Program will launch the Space Interferometry Mission (SIM), a 10 meter optical interferometer instrument, into a circular 900 km earth orbit. This instrument will be comprised of three collinear optical interferometers whose prime mission objectives are to perform astrometric measurements of unparalleled accuracy and to perform rotational synthesis imaging of stellar debris disks. To deal with the huge technical challenges of developing this instrument, innovative approaches to System Engineering are being tested and applied in order to achieve our target performance objectives. Defining requirements flow down from the highest system level to the detailed equipment specifications demands a tracing capability that has not been previously available or maintainable on past projects. The SLM System Engineering activity has chosen to utilize a requirements tracing tool to help it track changes and, hopefully, limit volumes of documentation that have become burdens in the past. Additionally, cross-cutting system models will be applied using new processes and infrastructure being instituted at JPL. Detailed models of optical systems, structural dynamics and thermal control systems are being implemented in an integrated fashion. The fidelity of these models will be verified in a series of evolving hardware and software testbeds that will culminate in a functioning ground version of the flight system. This testbed, supported by a separate technology program, will validate the system level requirements on astrometric performance, visibility and throughput. SIM will be one of the first missions to apply all of these techniques to enhance design detail and mitigate or retire risk early in it's development cycle. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kahn, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4311-5 PY 1998 BP 543 EP 551 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BL20J UT WOS:000074665200049 ER PT S AU Olson, CF AF Olson, CF GP IEEE COMP SOC IEEE COMP SOC TI Variable-scale smoothing and edge detection guided by stereoscopy SO 1998 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1998 IEEE Computer-Society Conference on Computer Vision and Pattern Recognition CY JUN 23-25, 1998 CL SANTA BARBARA, CA SP IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB It is typical in edge detection applications to examine a single scale or to consider some space of scales in the image without knowing which scale is appropriate for each location in the image. However, many images contain a wide variation in the distance to the scene points, and thus objects of the same size can appear at greatly differing scales in We image. We present a method where the scale of the smoothing and edge detection is varied locally according to the distance to the scene point, which we estimate through stereoscopy. The edges that are detected are thus at the same scale in the world rather than at the same scale in the image. This method has been implemented efficiently by smoothing the image at a discrete set of scales and performing interpolation to estimate the response at the correct scale for each pixel. The application of this technique to an ordnance recognition problem has resulted in a considerable improvement in performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 107-102, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-8186-8497-6 J9 PROC CVPR IEEE PY 1998 BP 80 EP 85 DI 10.1109/CVPR.1998.698591 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BL27E UT WOS:000074947400012 ER PT S AU Olson, CF AF Olson, CF GP IEEE COMP SOC IEEE COMP SOC TI A probabilistic formulation for Hausdorff matching SO 1998 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1998 IEEE Computer-Society Conference on Computer Vision and Pattern Recognition CY JUN 23-25, 1998 CL SANTA BARBARA, CA SP IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB Matching images based on a Hausdorff measure has become popular for computer vision applications. However, no probabilistic model has been used in these applications. This limits the formal treatment of several issues, such as feature uncertainties and prior knowledge. In this paper, we develop a probabilistic formulation of image matching in terms of maximum likelihood estimation that generalizes a version of Hausdorff matching. This formulation yields several benefits with respect to previous Hausdorff matching formulations. In addition, we shaw that the optimal model position in a discretized pose space can be located efficiently in this formation and we apply these techniques to a mobile robot self-localization problem. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 107-102, Pasadena, CA 91109 USA. NR 0 TC 23 Z9 24 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-8186-8497-6 J9 PROC CVPR IEEE PY 1998 BP 150 EP 156 DI 10.1109/CVPR.1998.698602 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BL27E UT WOS:000074947400023 ER PT S AU Burl, MC Perona, P AF Burl, MC Perona, P GP IEEE COMP SOC IEEE COMP SOC TI Using hierarchical shape models to spot keywords in cursive handwriting data SO 1998 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1998 IEEE Computer-Society Conference on Computer Vision and Pattern Recognition CY JUN 23-25, 1998 CL SANTA BARBARA, CA SP IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB Different instances of a handwritten word consist of the same basic features (humps, cusps, crossings, etc.) arranged in a deformable spatial pattern. Thus, keywords in cursive text can be detected by looking for the appropriate features in the "correct" spatial configuration. A keyword can be modeled hierarchically as a set of word fragments, each of which consists of lower-level features. To allow flexibility, the spatial configuration of keypoints within a fragment is modeled using a Dryden-Mardia (DM) probability density over the shape of the configuration. In a writer-dependent test on a transcription of the Declaration of Independence (similar to 1300 words, similar to 7500 characters), the method detected all eleven instances of the keyword "government" with only four false positives. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Burl, MC (reprint author), CALTECH, Jet Prop Lab, MS 525-3660, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-8186-8497-6 J9 PROC CVPR IEEE PY 1998 BP 535 EP 540 DI 10.1109/CVPR.1998.698657 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BL27E UT WOS:000074947400078 ER PT S AU Johnson, AE Hebert, M AF Johnson, AE Hebert, M GP IEEE COMP SOC IEEE COMP SOC TI Efficient multiple model recognition in cluttered 3-D scenes SO 1998 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1998 IEEE Computer-Society Conference on Computer Vision and Pattern Recognition CY JUN 23-25, 1998 CL SANTA BARBARA, CA SP IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB We present a 3-D shape-based object recognition system for simultaneous recognition of multiple objects in scenes containing clutter and occlusion. Recognition is based on matching surfaces by matching points using the.spin-image representation. The spin-image is a data level shape descriptor that is used to match surfaces represented as surface meshes. We present a compression scheme for spin-images that results in efficient multiple object recognition which we verify, with results showing the simultaneous recognition of multiple objects from a library of 20 models. Furthermore, we demonstrate the robust performance of recognition in the presence of clutter and occlusion through analysis of recognition trials on 100 scenes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 23 Z9 25 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-8186-8497-6 J9 PROC CVPR IEEE PY 1998 BP 671 EP 677 DI 10.1109/CVPR.1998.698676 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BL27E UT WOS:000074947400097 ER PT B AU Lohn, JD Colombano, SP Scargle, J Stassinopoulos, D Haith, GL AF Lohn, JD Colombano, SP Scargle, J Stassinopoulos, D Haith, GL GP IEEE TI Evolving catalytic reaction sets using genetic algorithms SO 1998 IEEE INTERNATIONAL CONFERENCE ON EVOLUTIONARY COMPUTATION - PROCEEDINGS SE IEEE Congress on Evolutionary Computation LA English DT Proceedings Paper CT IEEE International Conference on Evolutionary Computation CY MAY 04-09, 1998 CL ANCHORAGE, AK SP Int Neural Network Soc, IEEE, Neural Networks Council, IEEE, Alaska Sect AB In this paper we construct simple artificial chemistries in order to gain an understanding of how a chemical reaction network might emerge from a state of relative disorder in non-living "protocells." Such chemistries have relevance to origin of life studies as well as artificial life research. We present a model comprised of interacting polymers, and specify two initial conditions: a distribution of relatively disordered polymers and a fixed set of reversible catalytic reactions. A genetic algorithm is then used to find a set of reactions that exhibit pre-specified behavior. Our results show that reaction sets can be found to give polymer distributions that are biased towards longer polymers. We present examples of these protocell chemistries and show that the reaction sets found are robust in the sense that they produce desirable behavior in equilibrium.. Such a technique is useful because it allows an investigator to determine whether a specific distribution can be produced, and if it can, a reaction network can be found and then analyzed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lohn, JD (reprint author), NASA, Ames Res Ctr, MS 269-1, Moffett Field, CA 94035 USA. NR 0 TC 4 Z9 4 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4869-9 J9 IEEE C EVOL COMPUTAT PY 1998 BP 487 EP 492 DI 10.1109/ICEC.1998.699856 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA BL57Z UT WOS:000075926200084 ER PT B AU Berenji, HR Saraf, SK AF Berenji, HR Saraf, SK GP IEEE TI Competition and collaboration among fuzzy reinforcement learning agents SO 1998 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS AT THE IEEE WORLD CONGRESS ON COMPUTATIONAL INTELLIGENCE - PROCEEDINGS, VOL 1-2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems at the World Congress on Computational Intelligence (WCCI 98) CY MAY 04-09, 1998 CL ANCHORAGE, AK SP IEEE, Neural Networks Council, Int Neural Network Soc, IEEE, Alaska Sect AB GARIC-Q, introduced earlier, performs incremental Dynamic Programming using a society of intelligent agents which are controlled at the top level by Fuzzy Q-Learning and at the local level, each agent learns and operates based on GARIC, a technique for fuzzy reinforcement learning. In MULTI-GARIC-Q, agents can collaborate to investigate the state space by training a unique action evaluator which acts as a critic function for all the agents. MULTI-GARIC-Q2 extends MULTIGARIC-Q by providing more independence to each fuzzy reinforcement learning agent to investigate its state space for an extended time. After the interim learning period is over, all the agents engage in a competition to select a winner who will then continue its learning using the actual dynamic system. The rest of the agents continue learning using copies of a simulated plant. MULTI-GARIC-Q2 provides faster learning while allowing each agent to act and learn more independently. C1 NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, Moffett Field, CA 94035 USA. RP Berenji, HR (reprint author), NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, MS 269-2, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4863-X PY 1998 BP 622 EP 627 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BL20P UT WOS:000074668800111 ER PT B AU Akbarzadeh, MR Tunstel, E Kumbla, K Jamshidi, M AF Akbarzadeh, MR Tunstel, E Kumbla, K Jamshidi, M GP IEEE TI Soft computing paradigms for hybrid fuzzy controllers: Experiments and applications SO 1998 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS AT THE IEEE WORLD CONGRESS ON COMPUTATIONAL INTELLIGENCE - PROCEEDINGS, VOL 1-2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems at the World Congress on Computational Intelligence (WCCI 98) CY MAY 04-09, 1998 CL ANCHORAGE, AK SP IEEE, Neural Networks Council, Int Neural Network Soc, IEEE, Alaska Sect AB Neural Networks (NN), Genetic Algorithms (GA), and Genetic Programs (GP) are often augmented with fuzzy logic-based schemes to enhance artificial intelligence of a. given system. Such hybrid combinations are expected to exhibit added intelligence, adaptation, and learning ability. In this paper, implementation of three hybrid fuzzy controllers are discussed and verified by experimental results. These hybrid controllers consist of a hierarchical NN-fuzzy controller applied to a direct drive motor, a GA-fuzzy hierarchical controller applied to a flexible robot link, and a GP-fuzzy behavior-based controller applied to a mobile robot navigation task. It is experimentally shown that all three architectures are capable of significantly improving the system response. C1 Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. RP Akbarzadeh, MR (reprint author), Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4863-X PY 1998 BP 1200 EP 1205 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BL20P UT WOS:000074668800210 ER PT S AU Olson, CF Matthies, LH AF Olson, CF Matthies, LH GP IEEE TI Maximum likelihood rover localization by matching range maps SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB This paper describes maximum likelihood estimation techniques for performing rover localization in natural terrain by matching range maps. An occupancy map of the local terrain is first generated using stereo vision. The position of the rover with respect to a previously generated occupancy map is then computed by comparing the maps using a probabilistic formulation of image snatching techniques. Our motivation for this work is the desire for greater autonomy in Mars rovers. These techniques have been applied to data obtained from the Sojourner Mars rover and ran on-board the Rocky 7 Mars rover prototype. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 107-102, Pasadena, CA 91109 USA. NR 0 TC 24 Z9 28 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 272 EP 277 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900044 ER PT S AU Backes, PG Tso, KS Tharp, GK AF Backes, PG Tso, KS Tharp, GK GP IEEE TI Mars Pathfinder mission Internet-based operations using WITS SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB The Web Interface for Telescience (WITS) is an Internet-based tool that the Mars Pathfinder mission used for both mission operations at JPL and public outreach. WITS enables the viewing of downlinked images and results in various ways, terrain feature measurement and annotation, and planning of daily mission activities. WITS is written in the Java language and is accessible bgl mission scientists and the general public via a web browser. The public can use WITS to plan and simulate their own rover missions. WITS will also be used in the 1998 lander and 2001, 2003, and 2005 rover missions to Mars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Backes, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 7 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 284 EP 291 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900046 ER PT S AU Laubach, SL Burdick, J Matthies, L AF Laubach, SL Burdick, J Matthies, L GP IEEE TI An autonomous path planner implemented on the Rocky7 prototype microrover SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB Much prior work in mobile robot path planning has been based on assumptions that are unrealistic for exploration of planetary terrains. Based on the first author's experience with the Mars Pathfinder mission, this paper reviews issues that me critical for successful autonomous navigation of planetary revers. No currently proposed methodology accurately addresses all of these issues. We next report on an extension of the recently proposed "Tangent Bug" algorithm. The implementation of this extended algorithm on the Rocky 7 Mars Rover prototype at the Jet Propulsion Laboratory is described, and experimental results are presented In addition limitations encountered by the Sojourner rover in actual Martian terrain suggest that terrain traversability is a key issue for future interplanetary rover autonomous planning algorithms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Laubach, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,198-219, Pasadena, CA 91109 USA. NR 0 TC 15 Z9 16 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 292 EP 297 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900047 ER PT S AU Seraji, H Steele, R AF Seraji, H Steele, R GP IEEE TI Nonlinear contact control for Space Station dexterous arms SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB In October 1996, a research and development task was initiated at JPL to develop and demonstrate nonlinear contact control schemes for the dexterous robotic arms planned for the Space Station. This peeper reports on the progress made to-date in this task. Specifically, the paper introduces a new class of contact controllers comprised of a nonlinear gain in cascade with a linear fixed-gain PI force controller and PD compliance controller. The nonlinear gains used are simple hyperbolic functions of force error and contact force, respectively. The stability of the closed-loop systems incorporating nonlinear PI and PD controllers are investigated using the Popov Stability Criterion. Experimental results are presented to demonstrate the efficacy of the nonlinear force and compliance control schemes for a dexterous gamma-DOF Robotics Research arm. These results highlight the advantages of the proposed nonlinear contact controllers compared to conventional fixed-gain controllers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Seraji, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 899 EP 906 PG 4 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900143 ER PT S AU Ambrose, RO Diftler, MA AF Ambrose, RO Diftler, MA GP IEEE TI The minimum form of strength in serial, parallel and bifurcated manipulators SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB The described mathematical formulations answer the questions "how strong is enough?", "strong in which direction?", and "where is the weakest link?" that robot designers face in the early stages of matching tasks with robotic mechanisms. This work produces 3D visualizations of robot strengths and weaknesses across their dexterous workspaces, aiding interactive manipulator joint and kinematic design. Strength is defined here as the maximum force or moment that the robot can exert on the environment at its point of resolution. This strength is a 6x1 vector for spatial mechanisms, comprising forces and moments resolved in a global frame. The three factors studied in this work are the design of the manipulator's drive trains, the chain's kinematic parameters, and the articulation of kinematic redundancies as self motion. The mathematical formulation is implemented as a minimum of a set of serial strengths, within which can exist parallel sets as appropriate for the mechanism's kinematics. The strength model is first developed for serial chains, broadened to the statically indeterminant cases of parallel chains, and then applied to a bifurcated system of chains in development at NASA. This work's primary objective is to bring to bear in robot design the mathematical principles usually reserved for robot modeling and control. After a robot has been built, it is often too late to fix a mechanism's many weaknesses. It is our belief that the Jacobian has as much to teach robot designers as it has taught students of dynamics and control theory. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Ambrose, RO (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code ER4, Houston, TX 77058 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 1334 EP 1339 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900211 ER PT S AU Lee, SH Yi, CS AF Lee, SH Yi, CS GP IEEE TI An analytic approach to assembility analysis SO 1998 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 16-20, 1998 CL KATHOLIEKE UNIV LEUVEN, LEUVEN, BELGIUM SP IEEE, Robot & Automat Soc, Consiglio Nazl Ric, Fund Sci Res, Flanders, Belgium, Fraunhofer Inst Produktionstechnik & Automatisier, Commiss European Communities, INRIA, BULL, CNES, DAIMLER, KUKA, MATRA, SIEMENS, TECNOSPAZIO, THOMSON-CSF HO KATHOLIEKE UNIV LEUVEN AB The assemblability, which is the probability of successfully assembling the product parts, is directly related to the product cost. Especially, we consider the assembly failures due to tolerances. Because clearances provide the adjustability to part poses in an assembly, the assemblability analysis must be analyzed not only in terms of tolerances but also clearances. In this paper, we propose an analytic approach to the assemblability analysis. Represented by ellipsoids in a deviation space, the propagations of tolerances and clearances are calculated using Jacobian and sweep operations. The simulation results are given using a 2D assembly. The expected contribution of this paper is that the proposed method allows to compute the assemblability of a product in real time. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, SH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-4300-X J9 IEEE INT CONF ROBOT PY 1998 BP 1484 EP 1489 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BL12F UT WOS:000074368900235 ER PT S AU Romahn, S Callantine, TJ Palmer, EA AF Romahn, S Callantine, TJ Palmer, EA GP IEEE IEEE IEEE IEEE TI Model-based design of air traffic controller automation interaction SO 1998 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, VOLS 1-5 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98) CY OCT 11-14, 1998 CL SAN DIEGO, CA SP IEEE, Syst Man & Cybernet Soc AB A model of controller and automation activities was used to design the controller-automation interactions necessary to implement a new terminal area air traffic management concept. The model was then used to design a controller interface that provides the requisite information and functionality. Using data from preliminary study, the Crew Activity Tracking System (CATS) was used to help validate the model as a computational tool for describing controller performance. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Romahn, S (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-4778-1 J9 IEEE SYS MAN CYBERN PY 1998 BP 869 EP 874 PG 6 WC Computer Science, Cybernetics SC Computer Science GA BL88E UT WOS:000077033700150 ER PT S AU Noor, AK AF Noor, AK GP IEEE IEEE IEEE IEEE TI Future learning environment and impact of ISE SO 1998 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, VOLS 1-5 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98) CY OCT 11-14, 1998 CL SAN DIEGO, CA SP IEEE, Syst Man & Cybernet Soc AB Relevant technologies that can significantly impact education and training are described. The technologies are grouped into four categories: information technology and infrastructure, collaboration technology, modeling and simulation technology, and instructional technology. The synergistic combination of these technologies can dramatically increase the effectiveness of learning. Future learning environment is described in terms of learning objectives, instructional models and technologies. A proposed learning model is presented for preparing engineers to handle the complexities and uncertainties of future high-tech systems. The role of the Intelligent Synthesis Environment (ISE), being developed by NASA, University of Virginia and JPL, in the future learning environment is described. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-4778-1 J9 IEEE SYS MAN CYBERN PY 1998 BP 2692 EP 2697 PG 6 WC Computer Science, Cybernetics SC Computer Science GA BL88E UT WOS:000077033700470 ER PT S AU Noor, AK Venneri, SL AF Noor, AK Venneri, SL GP IEEE IEEE IEEE IEEE TI ISE provides a new frontier for synthesis of complex engineering products and missions SO 1998 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, VOLS 1-5 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98) CY OCT 11-14, 1998 CL SAN DIEGO, CA SP IEEE, Syst Man & Cybernet Soc AB The Intelligent Synthesis Environment (ISE) being developed by NASA, UVA and JPL for significantly enhancing the rapid creation of innovative affordable products and missions is described. ISE uses a synergistic combination of leading-edge technologies, including high performance computing, high-capacity communications and networking, virtual product development, knowledge-based engineering, computational intelligence, human-centered computing, and product information management. The environment will link scientists, design teams, manufacturers, suppliers and consultants who participate in the mission synthesis, as well as in the creation and operation of the aerospace system. It will radically advance the process by which complex science missions are synthesized, and high-tech engineering systems are designed, manufactured and operated. The five components critical to ISE are human-centered computing, infrastructure for distributed collaboration, rapid synthesis and simulation tools, life cycle integration and validation, and cultural change in the creative process. The first four components and some of their subelements are described in the paper. The fifth component is described in a succeeding paper. C1 Univ Virginia, Ctr Adv Computat Technol, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, Ctr Adv Computat Technol, NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-4778-1 J9 IEEE SYS MAN CYBERN PY 1998 BP 2698 EP 2703 PG 6 WC Computer Science, Cybernetics SC Computer Science GA BL88E UT WOS:000077033700471 ER PT S AU Patterson, FG Evans, RP AF Patterson, FG Evans, RP GP IEEE IEEE IEEE IEEE TI Perfecting the image SO 1998 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, VOLS 1-5 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98) CY OCT 11-14, 1998 CL SAN DIEGO, CA SP IEEE, Syst Man & Cybernet Soc AB This is a report on work in progress. It is about our continuing efforts to establish more effective approaches and models for system development. Our basic idea is that systems originate in the mind as a mental image, and that the system development task is to perfect the image. To perfect the image, our model at present represents a substantial change from the somewhat traditional approach of linear development with sequentially phased milestones. By contrast, our approach envisions a model of concurrent development that is characterized by a continuum of design decisions to "perfect the image" continuously and concurrently. Further, in our model, the image (the system) is perfected as a continuum of design decisions on three interdependent dimensions: (1) a mental image in a single mind, (2) a series of symbolic representations that sustain and enable a shared vision or image in a collective set of minds, e.g., the engineering team, and (3) the final image: the "developed" system. C1 NASA, Engn Training Program, Washington, DC 20546 USA. RP Patterson, FG (reprint author), NASA, Engn Training Program, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-4778-1 J9 IEEE SYS MAN CYBERN PY 1998 BP 2709 EP 2714 PG 6 WC Computer Science, Cybernetics SC Computer Science GA BL88E UT WOS:000077033700473 ER PT S AU Clancy, DJ AF Clancy, DJ GP IEEE IEEE IEEE IEEE TI Qualitative, model-based diagnosis of complex physical devices SO 1998 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, VOLS 1-5 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man, and Cybernetics - Intelligent Systems for Humans in a Cyberworld (SMC 98) CY OCT 11-14, 1998 CL SAN DIEGO, CA SP IEEE, Syst Man & Cybernet Soc AB In recent years, a great deal of interest has been generated regarding the application of qualitative, model-based techniques to the problem of fault detection and isolation. In general, model-based techniques use knowledge about the internal structure and behavior of a physical system to detect anomalies and diagnose the source of the anomalous behavior. These techniques are in contrast to traditional approaches that focus on an enumeration of the potential underlying disorders along with a description of how these disorders are manifested within the system behavior. In general, a model-based approach offers a more robust diagnostic system that can generatively reason about how components interact. This capability enables the detection and isolation of a wider class of system failures than what is commonly addressed using traditional techniques. In addition, use of a common inference engine along with a library of declarative models for commonly used devices can significantly reduce the time required to develop a robust diagnostic system. In this paper, we describe the basic paradigm that is commonly used for model-based anomaly detection and isolation. In particular, we are interested in techniques that use an abstract, qualitative representation as opposed to a precise numerical specification to describe the relevant structural and behavioral properties of the system. In general, these techniques describe the system using a structural model defining the qualitative relationships between a finite set of components coupled with a declarative specification of the valid behaviors for each component. The diagnostic engine reasons about the interaction between components to derive a description of the expected system behavior which in turn is used to detect discrepancies by comparing the expected behavior against the observations. Once a discrepancy is detected, the model is used to identify components whose failure could result in the observed behavior. This basic approach can be used when reasoning about either the steady state or the time varying behavior of both discrete and continuous systems. C1 NASA, Ames Caelum Res Ctr, Moffett Field, CA 94035 USA. RP Clancy, DJ (reprint author), NASA, Ames Caelum Res Ctr, MS 269-3, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-4778-1 J9 IEEE SYS MAN CYBERN PY 1998 BP 3012 EP 3019 PG 8 WC Computer Science, Cybernetics SC Computer Science GA BL88E UT WOS:000077033700525 ER PT B AU Kim, Q Stark, B Kayali, S AF Kim, Q Stark, B Kayali, S GP IEEE TI A novel, high resolution, non-contact channel temperature measurement technique SO 1998 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 36TH ANNUAL LA English DT Proceedings Paper CT 36th Annual IEEE International Reliability Physics Symposium CY MAR 31, 1996-APR 02, 1998 CL RENO, NV SP IEEE Electron Devices Soc, IEEE Reliabil Soc AB An in-situ optical technique based on infrared emission spectroscopy has been developed for noncontact measurement of the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). This method was demonstrated on a powered and un-powered GaAs MESFET, attaining a spatial resolution of 0.5 mu m. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Kim, Q (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 4800 Oak Grove Dr,MS 303-210, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4400-6 PY 1998 BP 108 EP 112 DI 10.1109/RELPHY.1998.670458 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA BK90C UT WOS:000073835800017 ER PT B AU Perez, R AF Perez, R GP IEEE IEEE TI Propagation effects on interference in wireless communication services SO 1998 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY - SYMPOSIUM RECORD, VOLS 1 AND 2 LA English DT Proceedings Paper CT 1998 International Symposium on Electromagnetic Compatibility CY AUG 24-28, 1998 CL DENVER, CO SP IEEE EMS Soc, Rocky Mt Chapter AB As a result of the congestion of the frequency spectrum, the geostationary orbit, and soon to be also low earth orbits, and the related widespread use of frequency sharing, consideration of interference has assumed an important role in earth-station siting and other aspects of telecommunication system design. interference may arise between terrestrial systems, between terrestrial and space systems, and between space systems. Attention is given here to interference involving space systems, whether between space systems or between space and terrestrial systems. Space-system earth stations, which commonly transmit high power and have sensitive receivers, may cause interference to terrestrial systems when transmitting and may be interfered with by terrestrial systems when receiving. In addition, one earth station may interfere with another. Also, earth stations may receive interfering, unwanted transmissions, as well as wanted signals, from satellites. Likewise satellites may receive interfering transmissions from other than the intended earth station, and terrestrial systems may receive interference from space stations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Perez, R (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5015-4 PY 1998 BP 86 EP 91 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA BM59X UT WOS:000079200400016 ER PT B AU Perez, R AF Perez, R GP IEEE IEEE TI Proper design of bypass capacitance in wideband operational amplifiers SO 1998 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY - SYMPOSIUM RECORD, VOLS 1 AND 2 LA English DT Proceedings Paper CT 1998 International Symposium on Electromagnetic Compatibility CY AUG 24-28, 1998 CL DENVER, CO SP IEEE EMS Soc, Rocky Mt Chapter AB Wideband operational amplifiers are essential in all signal acquisition and signal manipulation applications. Wide bandwidth operational amplifiers can accept a wide range of analog input frequencies and provide a wide range of outputs. However, inproper use of bypass capacitance can degrade the noise and stability performance of wideband amplifiers causing the correct output to be accompanied also but adjacent random outputs, or noise; which can quickly deteriorate the signal to noise ratio. A detailed study on the proper use of bypass capacitance in wideband amplifiers follows with the derivation of a series of design formulas. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Perez, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5015-4 PY 1998 BP 608 EP 613 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA BM59X UT WOS:000079200400116 ER PT B AU Dolinar, S Divsalar, D Pollara, F AF Dolinar, S Divsalar, D Pollara, F GP IEEE IEEE TI Turbo code performance as a function of code block size SO 1998 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY - PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY AUG 16-22, 1998 CL MIT, CAMBRIDGE, MA SP IEEE, Informat Theory Soc, Natl Sci Fdn, NASA, USN, Off Naval Res, AT&T, Motorola, Qualcomm, Lucent Technol, Bell Lab Innovat HO MIT AB We show that a single family of turbo codes is "nearly perfect" with respect to Shannon's sphere-packing bound, over a wide range of code rates and block sizes. We also assess the "imperfectness" of various non-turbo codes for comparison. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dolinar, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sam@shannon.jpl.nasa.gov NR 0 TC 8 Z9 8 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5000-6 PY 1998 BP 32 EP 32 DI 10.1109/ISIT.1998.708612 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA BL58H UT WOS:000075932800030 ER PT B AU Barth, JL Adolphsen, JW Gee, GB AF Barth, JL Adolphsen, JW Gee, GB GP IEEE IEEE TI Single event effects on commercial srams and power MOSFETs: Final results of the crux flight experiment on APEX SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB The CRUX experiment on the APEX satellite monitored single event effects on 1 Mbit and 256 Kbit SRAMs and 100 volt and 200 volt power MOSFETs. The single event upsets (SEUs) on the SRAMs were mapped in geographic and geomagnetic coordinates. Other single event effects (SEEs) were observed, including multiple bits upsets (MBUs) and single hard errors ("stuck bits"). Sensitivity to programmed logic state was also analyzed. The relatively large sample sizes for most part types and almost two year flight time in a hostile radiation environment provided a data set adequate for investigation of the range in device response within the flight lots. Single event burn-out (SEB) conditions were observed on the power MOSFETs. The rates on the 200 volt devices were much higher than on the 100 volt and occurred primarily in regions of space dominated by trapped protons. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barth, JL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 1 EP 10 DI 10.1109/REDW.1998.731465 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800001 ER PT B AU Coss, JR Swift, GM Selva, LE Titus, JL Normand, E Oberg, DL Wert, JL AF Coss, JR Swift, GM Selva, LE Titus, JL Normand, E Oberg, DL Wert, JL GP IEEE IEEE TI Compendium of single event failures in power MOSFETs SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB This compendium of SEGR and SEE data organizes results from several laboratories comparing failure thresholds for several different manufacturers and technologies. The results of this compendium are aimed at the designer to show the possible variations between manufacturers and processes. The compendium incorporates previously published data with the most recent data obtained from various sources. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Coss, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 15 EP 38 DI 10.1109/REDW.1998.731468 PG 24 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800003 ER PT B AU Nguyen, DN Lee, CI Johnston, AH AF Nguyen, DN Lee, CI Johnston, AH GP IEEE IEEE TI Total ionizing dose effects on flash memories SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB This paper presents the results of measurements performed on two different flash memory types, NOR and NAND technologies. The data suggest that the degradation is influenced by the activation of integrated charge pump circuits. The NAND type device functionally failed at lower TID level than the NOR technology, even when the NOR device was used with the charge pump activated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Nguyen, DN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 100 EP 103 DI 10.1109/REDW.1998.731486 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800013 ER PT B AU Lee, CI Johnston, AH Rax, BG AF Lee, CI Johnston, AH Rax, BG GP IEEE IEEE TI Total ionizing dose effects on voltage-to-frequency converters SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB Three different voltage-to-frequency converters were tested to determine how ionizing radiation affected their critical specifications. All three were fabricated with bipolar technologies. A popular charge-balancing architecture converter, AD652, was most sensitive with low dose rate (LDR) due to its tight specifications. The other astable-multivibrator architecture converters, AD537 and AD654, performed much better at high dose rate and low dose rate. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 117 EP 120 DI 10.1109/REDW.1998.731489 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800016 ER PT B AU Lee, CI Johnston, AH AF Lee, CI Johnston, AH GP IEEE IEEE TI Comparison of total dose effects on micropower op-amps: Bipolar and CMOS SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB Micropower op-amps; bipolar and CMOS, from Burr-Brown and Maxim are compared and critical parameters are characterized for total dose response with a 2.7V power supply voltage. The Burr-Brown bipolar device showed much more degradation than the CMOS device at high dose rate. The results are also compared with a NSC CMOS device. The Maxim bipolar device showed enhanced low dose rate effects. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 132 EP 136 DI 10.1109/REDW.1998.731492 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800019 ER PT B AU Sharma, AK Sahu, K Kniffin, S AF Sharma, AK Sahu, K Kniffin, S GP IEEE IEEE TI Evaluation of high performance converters under low dose rate total ionizing dose (TID) testing for NASA programs SO 1998 IEEE RADIATION EFFECTS DATA WORKSHOP LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 20-24, 1998 CL NEWPORT BEACH, CA SP IEEE, Nucl & Plasma Sci Soc, Inst Elect & Electr Engineers Inc AB This paper reports the results of low dose rate (0.02-0.04Rads(Si)/sec) TID tests performed on several types of high performance Analog-to-Digital and Digital-to-Analog Converters (ADCs/DACs). The test results showed that BiCMOS parts were very susceptible to radiation damage at very low levels [2-5kRads(Si)] and the bipolar parts showed higher tolerance [20-100kRads(Si)] depending on the part type and manufacturer. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sharma, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5109-6 PY 1998 BP 142 EP 147 DI 10.1109/REDW.1998.731494 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BM17C UT WOS:000077899800021 ER PT B AU Lee, S Yi, C AF Lee, S Yi, C GP IEEE IEEE TI Assembly analysis with augmented space method SO 1998 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS - PROCEEDINGS, VOLS 1-3: INNOVATIONS IN THEORY, PRACTICE AND APPLICATIONS LA English DT Proceedings Paper CT IEEE/RSJ International Conference on Intelligent Robots and Systems CY OCT 13-17, 1998 CL VICTORIA, CANADA SP IEEE, Ind Electr soc, IEEE, Robot & Automat Soc, Robot Soc Japan, Soc Instrumentat & Control Engineers, New Technol Fdn AB In this paper, we present an augmented space method to solve the assemblability of products where tolerances may prevent parts to assemble successfully. The accumulated tolerances of two serial chains of the parts are modeled by a hyper-ellipsoid in an augmented space. By the same token, the accumulated nominal clearances of two serial chains are modeled by a hyper-ellipsoid. Complete algorithms for solving the assemblability, tolerance, and clearance of parallel chains in the augmented space are described. This augmented space method gives a great computational advantage over simulation based methods, which is a necessary requirement for the real time assemblability analysis. Simulation results are given. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4465-0 PY 1998 BP 989 EP 994 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BL88G UT WOS:000077035300157 ER PT B AU Maimone, M Matthies, L Osborn, J Rollins, E Teza, J Thayer, S AF Maimone, M Matthies, L Osborn, J Rollins, E Teza, J Thayer, S GP IEEE IEEE TI A photo-realistic 3-D mapping system for extreme nuclear environments: Chornobyl SO 1998 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS - PROCEEDINGS, VOLS 1-3: INNOVATIONS IN THEORY, PRACTICE AND APPLICATIONS LA English DT Proceedings Paper CT IEEE/RSJ International Conference on Intelligent Robots and Systems CY OCT 13-17, 1998 CL VICTORIA, CANADA SP IEEE, Ind Electr soc, IEEE, Robot & Automat Soc, Robot Soc Japan, Soc Instrumentat & Control Engineers, New Technol Fdn AB We present a novel stereoscopic mapping system for use in post-nuclear accident operations. First we discuss a radiation shielded sensor array designed to tolerate extended cumulative dose using 4x shielding. Next, we outline procedures to ensure timely, accurate range estimation using trinocular stereo. Finally, we review the implementation of a system for the integration of range information into a 3-D, textured, metrically accurate surface mesh. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maimone, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4465-0 PY 1998 BP 1521 EP 1527 PG 7 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BL88G UT WOS:000077035300242 ER PT B AU Fang, WC AF Fang, WC BE Manolakos, ES Chandrakasan, A Chen, LG Burleson, WP Konstantinides, K TI A system-on-a-chip design of a low-power smart vision system SO 1998 IEEE WORKSHOP ON SIGNAL PROCESSING SYSTEMS-SIPS 98: DESIGN AND IMPLEMENTATION LA English DT Proceedings Paper CT 1998 IEEE Workshop on Signal Processing Systems - Design and Implementation (SiPS'98) CY OCT 08-10, 1998 CL CAMBRIDGE, MA SP IEEE Signal Proc Soc, IEEE Circuits & Syst Soc AB A low power smart imager design is proposed for real time machine vision applications. It takes advantages of recent advances in integrated sensing/processing designs, electronic neural networks, and sub-micron VLSI technology. The smart vision system integrates an active pixel camera with a programmable neural computer and an advanced microcomputer. A system-on-a-chip implementation of this smart vision system is shown to be feasible by integrating the whole system into a 3-cm x 3-cm chip design in a 0.18m CMOS technology. The on-chip neural computer provides one tera-operation-per-second computing power for various parallel vision operations and smart sensor functions. Its high performance is due to massively parallel computing structures, high data throughput rates, fast learning capabilities, and system-on-a-chip implementation. This highly integrated smart imager can be used for various scientific missions and other military, industrial or commercial vision applications. C1 CALTECH, Jet Prop Lab, NASA, Ctr Integrated Space Microsyst, Pasadena, CA 91109 USA. RP Fang, WC (reprint author), CALTECH, Jet Prop Lab, NASA, Ctr Integrated Space Microsyst, 4800 Oak Grove Dr,MS 198-219, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4997-0 PY 1998 BP 63 EP 72 DI 10.1109/SIPS.1998.715769 PG 10 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BL96E UT WOS:000077291700007 ER PT B AU Leidecker, H Hull, S AF Leidecker, H Hull, S GP IMAPS TI Vibration-induced fatigue failures in bonding wires used in stacked chip modules SO 1998 INTERNATIONAL CONFERENCE ON MULTICHIP MODULES AND HIGH DENSITY PACKAGING, PROCEEDINGS LA English DT Proceedings Paper CT 1998 International Conference on Multichip Modules and High Density Packaging (MCM 98) CY APR 15-17, 1998 CL DENVER, CO SP IMAPS, IEEE, CPMT, EIA, MCM DE resonance; fatigue; fracture; wire bond AB An instrument recently constructed at Goddard Space Flight Center involved stacked chip memory modules having about six thousand 1 mil gold wires, each between 4.6 mm and 6.1 mm long. Four bond wires fractured during the final box-level random vibration test which had spectral power to 850 Hz. We determined that these wires have fundamental resonant frequencies in the range from 1.4 kHz to 2.3 kHz, with quality factors up to 300, when the bonds at each end are rigid. However, a nearly severed top bond decreases the lead's fundamental frequency into the range from 600 Hz to 750 Hz. The lowered mode is strongly excited by the box-level vibration test, leading to fatigue-fracture of that already weakened bond during the several minutes of the vibration test. However, such a lowered mode would not be excited by previous shock and vibration tests since these happened to have no spectral power in the region from 600 Hz to 750 Hz. In separate tests, an unfractured 1 mil gold wire was still intact after 12 days (1.4 billion oscillations) at 1.4 kHz at a root-strain of 0.2%, while several (deliberately) nearly fractured wires failed after less than a minute (less than 41,000 oscillations) at 680 Hz at the same drive stress. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leidecker, H (reprint author), NASA, Goddard Space Flight Ctr, Code 562, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4850-8 PY 1998 BP 308 EP 313 DI 10.1109/ICMCM.1998.670799 PG 6 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Materials Science, Coatings & Films SC Computer Science; Engineering; Materials Science GA BK95T UT WOS:000073940900054 ER PT S AU Ponchak, GE Chen, D Yook, JG Katehi, LPB AF Ponchak, GE Chen, D Yook, JG Katehi, LPB GP SOC PHOTO OPT INSTRUMENTAT ENGINEERS SOC PHOTO OPT INSTRUMENTAT ENGINEERS TI Filled via hole fences for crosstalk control of microstrip lines in LTCC packages SO 1998 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1998 International Symposium on Microelectronics CY NOV 01-04, 1998 CL SAN DIEGO, CA SP Int Microelectron & Pkg Soc DE microstrip; coupling; LTCC packaging; microwave transmission lines; via holes AB Coupling between microstrip lines in dense RF packages is a common problem that degrades the circuit performance. To help alleviate this problem, metal filled via hole fences may be placed on both sides of the microstrip to provide better field confinement. In this paper, a 3D-FEM electromagnetic simulation of the problem is presented and if is shown that a single role of vias provides no reduction in the crosstalk. However, by connecting the tops of the vias with a single metal strip the crosstalk may be reduced by 8-10 dB. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-930815-52-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3582 BP 185 EP 189 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BM46L UT WOS:000078815800035 ER PT B AU Ellis, SR Menges, BM AF Ellis, SR Menges, BM BE MagnenatThalmann, N Thalmann, D TI Operator localization of virtual objects SO 1998 MULTIMEDIA MODELING, PROCEEDINGS LA English DT Proceedings Paper CT Multimedia Modeling Conference (MMM98) CY OCT 12-15, 1998 CL LAUSANNE, SWITZERLAND SP Silicon Graph, Comp Graph Soc, Swiss Fed Inst Technol, Univ Geneva AB Errors in the localization of nearby virtual objects presented via see-through, helmet mounted displays are examined as a function of viewing conditions and scene content Monocular, biocular or stereoscopic presentation of the virtual objects, accommodation (required focus), subjects' age, and the position of physical surfaces are examined. Nearby physical surfaces are found to introduce localization errors that differ depending upon the other experimental factors. The apparent physical size and transparency of the virtual objects and physical surfaces respectively are also influenced by their relative position when superimposed. Design implications are discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ellis, SR (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-8186-8911-0 PY 1998 BP 174 EP 183 DI 10.1109/MULMM.1998.722998 PG 10 WC Computer Science, Information Systems; Computer Science, Software Engineering SC Computer Science GA BM17E UT WOS:000077901400022 ER PT B AU Barniv, Y AF Barniv, Y BE Jain, LC TI Passive ranging using image expansion SO 1998 SECOND INTERNATIONAL CONFERENCE ON KNOWLEDGE-BASED INTELLIGENT ELECTRONIC SYSTEMS, KES'98 PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 2nd International Conference on Knowledge-Based Intelligent Electronic Systems (KES 98) CY APR 21-23, 1998 CL ADELAIDE, AUSTRALIA SP IEEE AB This paper describes a passive-ranging technique based on image-plane object expansion as its distance to the moving; camera decreases. The motion and shape of a, small window, assumingly found inside the boundaries of some object, is approximated by an affine transformation. The parameters of the transformation matrix -expansion, rotation, and translation- are derived by comparing successive images, and progressively increasing the image time separation. The increased baseline results in a triangulation accuracy which is much improved compared to that currently achievable. The algorithm's performance on flight data is presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Barniv, Y (reprint author), NASA, Ames Res Ctr, MS262-2, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4316-6 PY 1998 BP 243 EP 252 PG 10 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BL76J UT WOS:000076648800033 ER PT B AU Roberts, BC Knupp, KR Buechler, D AF Roberts, BC Knupp, KR Buechler, D GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI A low precipitation supercell over the Southeast US; A case study SO 19TH CONFERENCE ON SEVERE LOCAL STORMS LA English DT Proceedings Paper CT 19th Conference on Severe Local Storms CY SEP 14-18, 1998 CL MINNEAPOLIS, MN SP Amer Meteorol Soc ID THUNDERSTORMS C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Roberts, BC (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Code EL23, Huntsville, AL 35812 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 532 EP 535 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52X UT WOS:000079026500147 ER PT S AU Eldridge, JI Bansal, NP Bhatt, RT AF Eldridge, JI Bansal, NP Bhatt, RT BE Bray, D TI The evolution of interfacial sliding stresses during cyclic push-in testing of C- and BN-coated Hi-Nicalon fiber-reinforced CMCs SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL AB Interfacial debond cracks and fiber/matrix sliding stresses in ceramic matrix composites (CMCs) can evolve under cyclic fatigue conditions as well as with changes in the environment, strongly affecting the crack growth behavior, and therefore, the useful service lifetime of the composite. In this study, room temperature cyclic fiber push-in testing was applied to monitor the evolution of frictional sliding stresses and fiber sliding distances with continued cycling in both C- and BN-coated Hi-Nicalon SiC fiber-reinforced CMCs. A SiC matrix composite reinforced with C-coated Hi-Nicalon fibers as well as barium strontium aluminosilicate (BSAS) matrix composites reinforced with BN-coated (four different deposition processes compared) Hi-Nicalon fibers were examined. For failure at a C interface, test results indicated progressive increases in fiber sliding distances during cycling in room air but not in nitrogen. These results suggest the presence of moisture will promote crack growth when interfacial failure occurs at a C interface. While shortterm testing environmental effects were not apparent for failure at the BN interfaces, long-term exposure of partially debonded BN-coated fibers to humid air resulted in large increases in Fiber sliding distances and decreases in interfacial sliding stresses for all the BN coatings, presumably due to moisture attack. A wide variation was observed in debond and frictional sliding stresses among the different BN coatings. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Eldridge, JI (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 3 Z9 3 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 3 BP 11 EP 18 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BN01Q UT WOS:000080406200002 ER PT S AU Choi, SR Gyekenyesi, JP AF Choi, SR Gyekenyesi, JP BE Bray, D TI Elevated-temperature, 'ultra'-fast fracture strength of silicon nitride ceramics SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL ID HOT-PRESSED SI3N4; CRACK-PROPAGATION; FATIGUE BEHAVIOR; GROWTH AB The determination of 'ultra'-fast fracture strengths of five silicon nitride ceramics at elevated temperatures has been made by using constant stress-rate ("dynamic fatigue") testing in flexure with a series of 'ultra'-fast test rates. Of the five test materials, four silicon nitrides had elevated-temperature strengths that approached their respective room-temperature strengths at an 'ultra'-fast test rate of 3.3 x 10(4) MPa/s. This implies that slow crack growth (SCG) responsible for elevated-temperature failure can be eliminated or minimized by using an 'ultra'-fast test rate. These ongoing experimental results have shed light on laying a theoretical and practical foundation on the concept and definition of elevated-temperature "inert" strength behavior of advanced ceramics. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 3 BP 171 EP 179 PG 9 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BN01Q UT WOS:000080406200020 ER PT S AU Hurwitz, FI AF Hurwitz, FI BE Bray, D TI Filler polycarbosilane systems as CMC matrix precursors SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL ID PYROLYSIS AB Pyrolytic conversion of polymeric precursors to ceramics is accompanied by loss of volatiles and large volume changes. Infiltration of a low viscosity polymer into a fiber preform will fill small spaces within fiber tows by capillary forces, but create large matrix cracks within large, intertow areas. One approach to minimizing shrinkage and reducing the number of required infiltration cycles is to use particlulate fillers. In this study, Starfire allylhydridopolycarbosilane (AHPCS) was blended with a silicon carbide powder, with and without dispersant, using sheer mixing. The polymer and polymer/particle interactions were characterized using nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis and rheometry. Polymer/particulate slurries and suspensions were used to infiltrate a rigidized preform of an eight ply five harness satin CG Nicalon fiber having a dual layer BN/SiC interface coating, and the resulting composites characterized by optical and scanning electron microscopy. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hurwitz, FI (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 7 TC 5 Z9 5 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 3 BP 267 EP 274 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BN01Q UT WOS:000080406200030 ER PT S AU Salem, JA Ghosn, LJ Jenkins, MG AF Salem, JA Ghosn, LJ Jenkins, MG BE Bray, D TI Back-face strain as a method for monitoring stable crack extension SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Salem, JA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 19 TC 11 Z9 11 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 3 BP 587 EP 594 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BN01Q UT WOS:000080406200066 ER PT S AU Choi, SR Gyekenyesi, JP AF Choi, SR Gyekenyesi, JP BE Bray, D TI Some limitations in the elevated-temperature, constant stress-rate flexural testing for advanced ceramics with reference to the new, ambient-temperature test standard ASTM C 1368 SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL AB The room-temperature, constant stress-rate ("dynamic fatigue") flexural testing was performed in distilled water for 96 wt % alumina in accordance with new ASTM C 1368. The slow crack growth parameters were reasonably consistent (and reproducible), independent of the range and number of stress rates chosen. Despite some creep strains, the results of elevated-temperature, constant stress-rate testing for NC132 silicon nitride at 1100 degrees C and 96 wt % alumina at 1000 degrees C showed that one governing failure mechanism, slow crack growth, was associated with the material with reasonably consistent slow crack growth parameters for the chosen range of applied stress rates. Limitations regarding the material deterioration and the crack healing or blunting due to enhanced creep deformation were also discussed in conjunction with their effects on the estimation of slow crack growth parameters. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 3 BP 595 EP 605 PG 11 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BN01Q UT WOS:000080406200067 ER PT S AU Salem, T Noebe, R Manderscheid, J AF Salem, T Noebe, R Manderscheid, J BE Bray, D TI Reliability modeling of brittle anisotropic materials SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Salem, T (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 4 BP 57 EP 64 PG 8 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN01R UT WOS:000080406400007 ER PT S AU Ogbuji, LU AF Ogbuji, LU BE Bray, D TI Degradation of SiC/Bn/SiC composite in the burner rig SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL AB A SiC/BN/SiC composite with melt-infiltrated SiC matrix and High-Nicalon(TM) fiber reinforcements was exposed in a burner rig at 600-1200 degrees C, followed by mechanical testing and microstructural examination. Severe loss of strength and fracture strain occurred at 600-900 degrees C, and was attributed to degradation of the BN interphase with consequent bonding of adjacent fibers. Control samples oxidized in furnaces of various moisture contents were not so degraded. It is concluded that the fast removal of a C sublayer beneath the BN interphase provided a conduit for the pervasive penetration of the ambient from exposed fiber ends. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ogbuji, LU (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 2 Z9 2 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 4 BP 257 EP 264 PG 8 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN01R UT WOS:000080406400029 ER PT S AU Choi, SR AF Choi, SR BE Bray, D TI High-temperature slow crack growth, fracture toughness and room-temperature deformation behavior of plasma-sprayed ZrO2-8 wt % Y2O3 SO 22ND ANNUAL CONFERENCE ON COMPOSITES, ADVANCED CERAMICS, MATERIALS, AND STRUCTURES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures CY JAN 20-24, 1998 CL COCOA BEACH, FL ID COATINGS; FATIGUE AB Elevated-temperature slow crack growth and fracture toughness of the thick thermal barrier coatings of plasma-sprayed ZrO2-8 wt % Y2O3 Were determined in flexure at 800 degrees C in air. The coating material exhibited a high resistance to slow crack growth under constant stress-rate flexural test condition. The value of fracture toughness, K-IC approximate to 1.0 MPa root m, was obtained by a new SEVNB technique, consistent from room temperature to 800 degrees C. The stress-strain curves of the material exhibited a significant nonlinearity and hysteresis both in compression and in tension. This behavior also resulted in distortion of the output wave form in response to the input cyclic loading. The stress-strain relation was slightly dependent both on the number of loading and unloading cycles and on the test rate. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 18 TC 26 Z9 26 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 1998 VL 19 IS 4 BP 293 EP 301 PG 9 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BN01R UT WOS:000080406400033 ER PT S AU Cox, M Bhandari, N Shantz, M AF Cox, M Bhandari, N Shantz, M GP IEEE TI Multi-level texture caching for 3D graphics hardware SO 25TH ANNUAL INTERNATIONAL SYMPOSIUM ON COMPUTER ARCHITECTURE, PROCEEDINGS SE Conference Proceedings Annual International Symposium on Computer Architecture LA English DT Proceedings Paper CT 25th Annual International Symposium on Computer Architecture (ISCA 98) CY JUN 27-JUL 01, 1998 CL BARCELONA, SPAIN SP IEEE AB Traditional graphics hardware architectures implement what we call the push architecture for texture mapping. Local memory is dedicated to the accelerator for fast local retrieval of texture during rasterization, and the application is responsible for managing this memory. The push architecture has a bandwidth advantage, but disadvantages of limited texture capacity, escalation of accelerator memory requirements (and therefore cost), and poor memory utilization. The push architecture also requires the programmer to solve the bin-packing problem of managing accelerator memory each frame. More recently graphics hardware on PC-class machines has moved to an implementation of what we call the poll architecture. Texture is stored in system memory and downloaded by the accelerator as needed. The pull architecture has advantages of texture capacity, stems the escalation of accelerator memory requirements, and has good memory utilization. It also frees the programmer from accelerator texture memory management. However, the pull architecture suffers escalating requirements for bandwidth from main memory to the accelerator. In this paper we propose multi-level texture caching to provide the accelerator with the bandwidth advantages of the push architecture combined with the capacity advantages of the pull architecture. We have studied the feasibility of 2-level caching and found the following: (1) significant re-use of texture between frames; (2) L2 caching requires significantly less memory than the push architecture; (3) L2 caching requires significantly less bandwidth from host memory than the pull architecture; (4) L2 caching enables implementation of smaller L1 caches that would otherwise bandwidth-limit accelerators on the workloads in this paper. Results suggest that an L2 cache achieves the original advantage of the pull architecture stemming the growth of local texture memory - while at the same time stemming the current explosion in demand for texture bandwidth between host memory and the accelerator. C1 NASA, Ames Res Ctr, MRJ, Moffett Field, CA 94035 USA. RP Cox, M (reprint author), NASA, Ames Res Ctr, MRJ, Moffett Field, CA 94035 USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6897 BN 0-8186-8491-7 J9 CONF PROC INT SYMP C PY 1998 BP 86 EP 97 DI 10.1109/ISCA.1998.694765 PG 12 WC Computer Science, Hardware & Architecture SC Computer Science GA BL21J UT WOS:000074685600008 ER PT B AU Montgomery, DR Pichel, W Clemente-Calon, P AF Montgomery, DR Pichel, W Clemente-Calon, P GP ISRSE ISRSE TI The use of satellite-based SAR in support of fisheries enforcement applications SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm AB Satellite-based synthetic aperture radar (SAR) may provide a unique surveillance and monitoring capability to augment existing fisheries aircraft and patrol vessel reconnaissance methods. Moreover, satellite-based SAR may prove to be an effective tool to observe the effects of manmade land disturbances to fisheries habitat Three experiments were undertaken to assess the utility of satellite-based SAR in fisheries enforcement applications. One experiment involved the detection of fishing vessels and their wakes. Undersea acoustic measurements were made to study the effect of the blended SAR and acoustic signature data on detection and tracking of ships. A second experiment assessed the capability of SAR to detect large-scale pelagic driftnets. A third experiment involved SAR observations of sensitive salmon spawning and nursery habitat in the Pacific Northwest. This paper describes these three experiments and preliminary results. Further, the paper provides an assessment of the operational application of SAR to fisheries enforcement. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Montgomery, DR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 131 EP 134 PG 4 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800031 ER PT B AU Unninayar, S Weber, JD Schiffer, RA AF Unninayar, S Weber, JD Schiffer, RA GP ISRSE ISRSE TI Global change: An analysis of the time scales of change, problems with the identification/attribution of cause, and implications on observing systems SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm AB With improvements in space-based observing technology more and more physical, chemical and biological features of the Earth system are being monitored. The singular advantage of space-based observations is that they provide large-scale and global coverage. Over "time" they "can" provide a "quantitative" and visual assessment of global change. The requirements for absolute accuracy and precision, calibration, stability etc. are vastly different depending on the parameter being monitored and the time-scale or time window of its use/application. The evidence of "global change" from space-based observations on intra-annual and to some extent inter-annual time scales is reasonably clear and possibly unambiguous. Good examples are global total column ozone concentrations and distributions, sea surface temperature, vegetation characteristics and change, sea level or sea surface topography, land cover, snow and sea ice cover, cloud cover, outgoing long-wave radiation at the top of the atmosphere, precipitation estimates-- there are several others. To quantitatively assess change on time scales longer than several years, long-term continuity and absolute calibration are required. The attribution of "cause" is a more complex question which must deal with the time duration of the measurement system embedded in the context of the time scales of change of the parameter in question in the natural system. C1 NASA, Goddard Space Flight Ctr, CESDIS, Greenbelt, MD 20771 USA. RP Unninayar, S (reprint author), NASA, Goddard Space Flight Ctr, CESDIS, Code 661, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 236 EP 239 PG 4 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800058 ER PT B AU Wetzel, PJ AF Wetzel, PJ GP ISRSE ISRSE TI The "icehouse effect" and potential for observing it from space SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm ID ARCTIC-OCEAN; LEVEL; LAYER AB An icehouse preserves cold in the presence of external heat. A stable atmospheric boundary layer (ABL) can do likewise. I refine previous findings of a surface cooling trend in Arctic autumn and winter (Kahl et al., 1993; Walsh, 1993; Kahl et al., 1996) using an analysis of surface temperature stratified by a proxy for ABL stability: the temperature difference between the surface and 850hPa. Cooling is found to selectively occur in the temperature difference range corresponding to weak to moderate stability, while a climate warming signal is found in the unstable and very stable wings of the stability spectrum. I construct a numerical model which reproduces these observations. Model assumptions are physically plausible, but need validation. Model analysis yields a hypothetical cause and effect: air modified by a greenhouse-warmed ocean strengthens stability over adjacent snow. The resulting shallower ABL cools more quickly during clear sky periods. A key intensifier of the cooling rate is a shallow fog or ice haze-a common phenomenon during the dehydration of airmasses reaching the Arctic (Blanchet and Girard, 1994, 1995.) C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wetzel, PJ (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 270 EP 273 PG 4 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800067 ER PT B AU Klein, AG Hall, DK Riggs, GA AF Klein, AG Hall, DK Riggs, GA GP ISRSE ISRSE TI Global snow cover monitoring using MODIS SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm AB Daily snow-cover maps will be produced from the visible and near infrared images collected by MODIS - the Moderate Resolution Imaging Spectroradiometer. MODIS is scheduled for launch in summer 1998 aboard the first NASA Earth Observing System (EOS) Platform. A suite of MODIS snow cover products will be produced ranging from a 500-meter daily snow map created from individual MODIS image swaths, to temporally- and spatially- composited products suitable for use as input to General Circulation Models (GCMs). MODIS snow cover products wilt be distributed through the US. National Snow and Ice Data Center (NSIDC) in a special version of the Hierarchical Data Format designed specifically for the EOS program (HDF-EOS). The cost for MODIS snow-cover products will be the marginal costs of reproduction. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Klein, AG (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Hall, Dorothy/D-5562-2012 NR 5 TC 1 Z9 1 U1 0 U2 2 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 363 EP 366 PG 4 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800088 ER PT B AU Dolan, K Sabelhaus, P Williams, D AF Dolan, K Sabelhaus, P Williams, D GP ISRSE ISRSE TI Landsat 7 - Extending 25 years of global coverage SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm AB Since the launch of the first Landsat (ERTS-1) 25 years ago a continuous archive of thematic images of our changing earth have been collected. The National Aeronautics and Space Administration's (NASA) Earth Science Program will extend this legacy when it launches the Landsat 7 satellite in early 1999, with its main objective of acquiring and periodically refreshing a data set of the global land mass. This system will capture, process to Level OR, and archive 250 Enhanced Thematic Mapper Plus scenes per day. User access to the archive will be via the Earth Resources Observation System (EROS) Data Center Distributed Active Archive Center (EDC DAAC) In Sioux Falls, South Dakota. Up to 100 scenes from the archive can be systematically corrected to Level 1 and distributed to users each day. In addition, International Ground Stations will acquire Landsat 7 data within their local areas. This will significantly enhance the quantity and availability of data for users worldwide. C1 NASA, Goddard Space Flight Ctr, Landsat Project Off, Greenbelt, MD 20771 USA. RP Dolan, K (reprint author), NASA, Goddard Space Flight Ctr, Landsat Project Off, Code 430, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 622 EP 625 PG 4 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800154 ER PT B AU Ellickson, J AF Ellickson, J GP ISRSE ISRSE TI A preview of Landsat 7 mission operations building on the Landsat heritage SO 27TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, PROCEEDINGS: INFORMATION FOR SUSTAINABILITY LA English DT Proceedings Paper CT 27th International Symposium on Remote Sensing of Environment CY JUN 08-12, 1998 CL TROMSO, NORWAY SP Norsk Romsenter (Norwegian Space Ctr), Miljoverndepartementet, CIESIN, USGS, NASA, NOAA, UNEP, ESA, EUMETSAT, Kongsberg Spacetec AS, Space Applicat Inst, Joint Res Ctr European commiss, Tromso Satellite Stn AS, Space Imaging EOSAT, Norwegian Minist Environm AB Landsat 7 operations, scheduled to commence in the Spring of 1999, will continue more than 25 years of continuous multi-spectral imaging of the Earth's surface by Landsat satellites. Many key features of the Landsat 4 and 5 satellites will be continued, while important enhancements have been added. The resulting system will provide a valuable source of Earth observation data for a broad and diverse community. C1 NOAA, NESDIS, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ellickson, J (reprint author), NOAA, NESDIS, Goddard Space Flight Ctr, Landsat 7 Project,Code 430, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU NORSK ROMSENTER PI OSLO PA POSTBOKS 85 SMESTAD, 0309 OSLO, NORWAY BN 82-7542-040-7 PY 1998 BP 626 EP 628 PG 3 WC Environmental Sciences; Remote Sensing SC Environmental Sciences & Ecology; Remote Sensing GA BM34W UT WOS:000078443800155 ER PT S AU Seery, BD Smith, EP Mather, JC AF Seery, BD Smith, EP Mather, JC GP ESA ESA TI NASA's Next Generation Space Telescope visiting a time when galaxies were young SO 34TH LIEGE INTERNATIONAL ASTROPHYSICS COLLOQUIUM - THE NEXT GENERATION SPACE TELESCOPE SCIENCE DRIVERS AND TECHNOLOGICAL CHALLENGES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 34th Liege Astrophysics Colloquium on the Next Generation Space Telescope Science Drivers and Technological Challenges CY JUN 15-18, 1998 CL LIEGE, BELGIUM SP ESA, ESO, NASA, STScl, Univ Liege, Fonds Natl Rech Sci, Communaute Francaise, AMOS, CSL, Spacebel Instrumentat, HiServ DE active optics; Next Generation Space Telescope; deployables; detectors AB With the discovery of galaxies that existed when the universe was very young (approximately 5 percent of its current age), of planets not in our own solar system, and with the tantalizing evidence that the conditions for life may have existed within our solar system on planets or moons outside of the earth system, the past year has seen an explosion of interest in astronomy. In particular, a new era of exploration and understanding seems imminent, where the connection between the existence for the conditions of life will be connected to the origin of galaxies, stars and planets within the Universe. Who knows where this quest for knowledge will take us? C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Seery, BD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-716-X J9 ESA SP PUBL PY 1998 VL 429 BP 13 EP 22 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BM01V UT WOS:000077430300002 ER PT S AU Williger, GM Francis, PJ Woodgate, BE Malumuth, E AF Williger, GM Francis, PJ Woodgate, BE Malumuth, E GP ESA ESA TI On the nature of red galaxies in the early universe SO 34TH LIEGE INTERNATIONAL ASTROPHYSICS COLLOQUIUM - THE NEXT GENERATION SPACE TELESCOPE SCIENCE DRIVERS AND TECHNOLOGICAL CHALLENGES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 34th Liege Astrophysics Colloquium on the Next Generation Space Telescope Science Drivers and Technological Challenges CY JUN 15-18, 1998 CL LIEGE, BELGIUM SP ESA, ESO, NASA, STScl, Univ Liege, Fonds Natl Rech Sci, Communaute Francaise, AMOS, CSL, Spacebel Instrumentat, HiServ AB Increasing numbers of extremely red galaxies are being found in the high redshift (> 2) universe. These galaxies, which may have space densities as high as several per square arcmin, are defined by their extremely red optical/near-IR colours (R - K > 5) and are remarkably luminous in the near-IR (K similar to 19). They clearly represent a different population from the now commonplace Ly-break galaxies. What are these red galaxies? One theory suggests that they are dusty starburst galaxies. Alternatively, they could be massive galaxies, with stellar populations so old that they must have completed the bulk of their star formation before redshift 5. Either way, these galaxies pose a challenge to standard cosmological models, and either way, they are prime targets for the NGST. We present NICMOS imaging and accurate near-IR photometry of one of these red galaxies. It turns out to be a merging pair of early-type galaxies, each of which is massive and composed of an old stellar population. The pair are surrounded by a vast (> 100 kpc) lumpy neutral hydrogen cloud. Remarkably little star formation is taking place. These observations may be consistent with hierarchical models of giant elliptical galaxy formation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Williger, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-716-X J9 ESA SP PUBL PY 1998 VL 429 BP 261 EP 265 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BM01V UT WOS:000077430300037 ER PT S AU Greenhouse, MA Bely, P Bitzel, R Burg, R DiPirro, M Federline, B Gardner, JP Guy, P Hagopian, J Hein, J Jurotich, M Lawrence, J Martineau, B Martino, T Mather, J Mentzell, E Petro, L Satyapal, S Stanley, D Stockman, P Teplitz, H Travis, J Wilson, M AF Greenhouse, MA Bely, P Bitzel, R Burg, R DiPirro, M Federline, B Gardner, JP Guy, P Hagopian, J Hein, J Jurotich, M Lawrence, J Martineau, B Martino, T Mather, J Mentzell, E Petro, L Satyapal, S Stanley, D Stockman, P Teplitz, H Travis, J Wilson, M GP ESA ESA TI The NGST Integrated Science Instrument Module SO 34TH LIEGE INTERNATIONAL ASTROPHYSICS COLLOQUIUM - THE NEXT GENERATION SPACE TELESCOPE SCIENCE DRIVERS AND TECHNOLOGICAL CHALLENGES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 34th Liege Astrophysics Colloquium on the Next Generation Space Telescope Science Drivers and Technological Challenges CY JUN 15-18, 1998 CL LIEGE, BELGIUM SP ESA, ESO, NASA, STScl, Univ Liege, Fonds Natl Rech Sci, Communaute Francaise, AMOS, CSL, Spacebel Instrumentat, HiServ AB An Integrated Science Instrument Module (ISIM) design is under ongoing development for integration with the "Yardstick" (see Eely et al. these proceedings) and other NGST 8 m architectures that are intended for packaging in an EELV or Ariane 5 meter class fairing. The goals of this activity are to: [1] demonstrate mission science feasibility, [2] assess ISIM engineering and I&T feasibility, [3] asses ISIM cost feasibility, [4] identify ISIM technology challenge areas, [5] identify ISIM/NGST interface constraints, and [6] enable smart customer procurement of the ISIM. Ongoing progress can be monitored at: http://www701. gsfc.nasa. gov/isim/isim.htm. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Greenhouse, MA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-716-X J9 ESA SP PUBL PY 1998 VL 429 BP 275 EP 278 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BM01V UT WOS:000077430300039 ER PT S AU Redding, D Basinger, S Lowman, AE Shi, F Bely, P Burg, R Mosier, G AF Redding, D Basinger, S Lowman, AE Shi, F Bely, P Burg, R Mosier, G GP ESA ESA TI Wavefront sensing and control for the Next Generation Space Telescope SO 34TH LIEGE INTERNATIONAL ASTROPHYSICS COLLOQUIUM - THE NEXT GENERATION SPACE TELESCOPE SCIENCE DRIVERS AND TECHNOLOGICAL CHALLENGES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 34th Liege Astrophysics Colloquium on the Next Generation Space Telescope Science Drivers and Technological Challenges CY JUN 15-18, 1998 CL LIEGE, BELGIUM SP ESA, ESO, NASA, STScl, Univ Liege, Fonds Natl Rech Sci, Communaute Francaise, AMOS, CSL, Spacebel Instrumentat, HiServ AB The Next Generation Space Telescope will achieve high optical quality and stability without use of massive structures. Stability for its large, flexible, lightweight deployed structure is provided by its benign orbital operating environment. Active wavefront controls will compensate misalignments and figure errors incurred during launch and cool-down on orbit. This paper presents a baseline architecture for NGST wavefront controls, including initial capture and alignment, segment phasing, wavefront sensing and deformable mirror control. Simulations and analyses illustrate expected scientific performance with respect to figure error, misalignments, and thermal deformation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Redding, D (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-716-X J9 ESA SP PUBL PY 1998 VL 429 BP 285 EP 294 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BM01V UT WOS:000077430300041 ER PT S AU Smith, EP Offenberg, J Bely, PY AF Smith, EP Offenberg, J Bely, PY GP ESA ESA TI SimNGST: The Next Generation Space Telescope mission simulator SO 34TH LIEGE INTERNATIONAL ASTROPHYSICS COLLOQUIUM - THE NEXT GENERATION SPACE TELESCOPE SCIENCE DRIVERS AND TECHNOLOGICAL CHALLENGES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 34th Liege Astrophysics Colloquium on the Next Generation Space Telescope Science Drivers and Technological Challenges CY JUN 15-18, 1998 CL LIEGE, BELGIUM SP ESA, ESO, NASA, STScl, Univ Liege, Fonds Natl Rech Sci, Communaute Francaise, AMOS, CSL, Spacebel Instrumentat, HiServ DE space astronomy; software; NGST AB Constructing complex space telescopes requires juggling many competing factors. Almost every design choice you can make involves the cost, the science return and/or the size of the telescope. What decisions must be made to build a telescope that is powerful enough to see the most distant galaxies, is light enough to be launched on a medium size rocket, and will operate for many years - without spending more than $900 million? The NGST Mission simulator models the work that astronomers, scientists and engineers at several institutions are doing for NASA today. We employ the NGST Design Reference Mission to construct our science objectives. These goals are mated with several cost models to assess the impact of each program on the mission cost. SimNGST is written in JavaScript and is available via the World Wide Web (WWW) in both expert and novice modes (http://ngst.gsfc.nasa.gov/SimNGST/). C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Smith, EP (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-716-X J9 ESA SP PUBL PY 1998 VL 429 BP 301 EP 305 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BM01V UT WOS:000077430300043 ER PT B AU Cano, RJ Weiser, ES St Clair, TL Echigo, Y Kaneshiro, H AF Cano, RJ Weiser, ES St Clair, TL Echigo, Y Kaneshiro, H BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Composite properties of polyimide resins made from "salt-like" solution precursors SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE composites; polyimides; prepreg; and processing AB Recent work in high temperature materials at NASA Langley Research Center (LaRC(TM)) have led to the development of new polyimide resin systems with very attractive properties. The majority of the work done with these resin systems has concentrated on determining engineering mechanical properties of composites prepared from a poly(amide acid) precursor. Three NASA Langley-developed polyimide matrix resins, LaRC(TM)-IA, LaRC(TM)-IAX, and LaRC(TM)-8515, were produced via a "salt-like" process developed by Unitika Ltd. The "salt-like" solutions (sixty-five percent solids in NMP) were prepregged onto Hexcel IM7 carbon fiber using the NASA LaRC(TM) Multipurpose Tape Machine. Process parameter; were determined and composite panels fabricated. Mechanical properties are presented for these three intermediate modulus carbon fiber/polyimide matrix composites and compared to existing data on the same polyimide resin systems and IM7 carbon fiber manufactured via poly(amide acid) solutions (thirty-five percent solids in NMP). This work studies the effects of varying the synthetic route on the processing and mechanical properties of polyimide composites. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cano, RJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 2 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 81 EP 92 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500008 ER PT B AU Smith, JG Connell, JW Hergenrother, PM AF Smith, JG Connell, JW Hergenrother, PM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI The effect of molecular weight on the composite properties of cured phenylethynyl terminated imide oligomers SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE high temperature polymers; polyimides; phenylethynyl containing imides; adhesives; carbon fiber composites; oligomeric thermosetting imides AB As part of a program to develop high temperature/high performance structural resins for aeronautical applications, imide oligomers containing terminal phenylethynyl groups with calculated number average molecular weights of 1250, 2500 and 5000 g/mol were prepared, characterized, and evaluated as adhesives and composite matrix resins. The goal of this work was to develop resin systems that are processable using conventional processing equipment into void free composites that exhibit high mechanical properties with long term high temperature durability, and are not affected by exposure to common aircraft fluids. The imide oligomers containing terminal phenylethynyl groups were fabricated into titanium adhesive specimens and IM-7 carbon fiber laminates under 0.1 - 1.4 MPa for 1 hr at 350-371 degrees C. The lower molecular weight oligomers exhibited higher cured Tg, better processability, and better retention of mechanical properties at elevated temperature without significantly sacrificing toughness or damage tolerance than the higher molecular weight oligomer. The neat resin, adhesive and composite properties of the cured polymers will be presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, JG (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 3 Z9 3 U1 1 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 93 EP 105 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500009 ER PT B AU Cano, RJ Belvin, HL Weiser, ES McGowen, DM AF Cano, RJ Belvin, HL Weiser, ES McGowen, DM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Fabrication of structural components from solution coated polyimide prepreg SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE composites; polyimides; prepreg; processing; and structure AB Recent advancements in high temperature materials at NASA Langley Research Center have led to the development of new polyimide resin systems with very attractive properties. The majority of the work done with these resin systems has concentrated on determining engineering mechanical properties from flat composite coupons. Since future advanced civilian aerospace components will require fabrication and testing of built-up structure from these high temperature composite materials, their processablity into structural components needed to be demonstrated. The NASA Langley-developed polyimide matrix resin, LaRC(TM)-PETI-5, was scaled to large quantities and solution prepregged onto Hercules IM7 carbon fiber by Fiberite Corporation. Using this prepreg which contained 20-22 percent N-methylpyrrolidinone solvent, techniques were developed to fabricated fully consolidated stiffener reinforced flat panels. The techniques included the use of movable metal tooling alone or in combination with trapped fluoroelastomer rubber. Methods were developed to remove all solvent prior to consolidation and to apply pressure uniformly to all sections of the part. Single stringer panels were made and machined into crippling and stiffener pull-off specimens. Panels with multiple stringers were also fabricated. Overall, the structural elements fabricated were of high quality and exhibited excellent mechanical properties. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cano, RJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 144 EP 157 PG 14 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500013 ER PT B AU Sutter, JK Ortiz, R Greene, PW Jobe, JM AF Sutter, JK Ortiz, R Greene, PW Jobe, JM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Effects of trace metals on the thermo-oxidative stability of 6F polyimides SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE polyimide; 6F dianhydride and thermo-oxidative stability AB Polyimides containing [Hexafluoroisopropylidene-2,2-bis(phthalic acid anhydride)] or 6F dianhydride have many potential applications in high temperature oxidative environments such as aircraft engines or electronic circuitry. In many of these applications, polyimide resins or their composites are in direct contact with metals. This study investigates the effects of trace metals in or on the surface of PMR-II-50; an addition polyimide developed at NASA Lewis Research Center.(1) Specifically, we focused on (1) determining what, if any, effect on percent weight loss of PMR-II-50 after 956 hours at 316 degrees C could be attributed to the type of 6F dianhydride (polymer or electronic grade), processing time at 371 degrees C and the presence of Kapton(R) as a barrier film, to prevent or minimize diffusion of metal from the tool steel into the polyimide; (2) determining what, if any, effect on iron content in PMR-II-50 could be attributed to type of 6F dianhydride, processing time at 371 degrees C and the presence of Kapton(R) and (3) discovering any possible relationship between percent weight loss and iron content. Resin type significantly affected TOS; while processing time and using Kapton(R) had no significant effect on PMR-II-50 resin TOS. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Sutter, JK (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 158 EP 170 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500014 ER PT B AU Hansen, PA Townsend, JA Yoshikawa, Y Castro, JD Triolo, JJ Peters, WC AF Hansen, PA Townsend, JA Yoshikawa, Y Castro, JD Triolo, JJ Peters, WC BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Degradation of Hubble Space Telescope metallized Teflon((R)) FEP thermal control materials SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE Hubble Space Telescope; multi-layer insulation; Teflon (R) Fluorinated Ethylene Propylene (FEP) AB The mechanical and optical properties of the metallized Teflon(R) Fluorinated Ethylene Propylene (FEP) thermal control materials on the Hubble Space Telescope GIST) have degraded over the seven years the telescope has been in orbit. Astronaut observations and photographic documentation from the Second Servicing Mission revealed severe cracks of the multi-layer insulation (MLI) blanket outer layer in many locations around the telescope, particularly on solar facing surfaces. Two samples, the outer Teflon(R) FEP MLI layer and radiator surfaces, were characterized post-mission through exhaustive mechanical, thermal, chemical, and optical testing. The observed damage to the thermal control materials, the sample retrieval and handling, and the significant changes to the radiator surfaces of HST will be discussed. Each of these issues is addressed with respect to current and future mission requirements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hansen, PA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 570 EP 581 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500054 ER PT B AU Townsend, JA Hansen, PA Dever, JA Triolo, JJ AF Townsend, JA Hansen, PA Dever, JA Triolo, JJ BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Analysis of retrieved Hubble Space Telescope thermal control materials SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE LEO environmental effects; Teflon((R)) FEP (fluorinated ethylene propylene); Hubble Space Telescope AB The mechanical and optical properties of the thermal control materials on the Hubble Space Telescope (HST) have degraded over the nearly seven years the telescope has been in orbit. Astronaut observations and photographs from the Second Servicing Mission (SM2) revealed large cracks in the metallized Teflon(R) FEP, the outer layer of the multi-layer insulation:(MLI), in many locations around the telescope. Also, the emissivity of the bonded metallized Teflon(R) FEP radiator surfaces of the telescope has increased over time. Samples of the top layer of the MLI and radiator material were retrieved during SM2, and a thorough investigation into the degradation followed in order to determine the primary cause of the damage. Mapping of the cracks on HST and the ground testing showed that thermal cycling with deep-layer damage from electron and proton radiation are necessary to cause the observed embrittlement. Further, strong evidence was found indicating that chain scission (reduced molecular weight) is the dominant form of damage to the metallized Teflon(R) FEP. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Townsend, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 582 EP 593 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500055 ER PT B AU Wang, L AF Wang, L BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Mechanical properties and fractography of MLI FEP from the HST second service mission SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE fractography; FEP materials; Hubble Space Telescope AB Tensile tests and fractography of MLI Teflon(TM) (FEP) outer surface layer retrieved during the Hubble Space Telescope (HST) second servicing mission were performed as part of the effort to investigate the failure mechanism of the MLI observed during the second service mission. The fracture surfaces of a tensile test sample as well as a bend-cracked sample were also analyzed for comparison purpose. The surface morphology of the Teflon and aluminum was compared with that of a pristine sample. Fractography analysis shows that the samples exhibit three kinds of distinctive fracture surfaces, although the material has been severely embrittled in space. They are classified as shear fracture, fibrous fracture and smooth fracture based on the fracture surface morphology. The shear fracture is due to a cut by scissors or other cutting devices. Bending and/or tension of the sample during the handling created the fibrous fracture. The smooth fracture occurred in space. The fracture that occurred in space can not be duplicated by tension and/or bending of the embrittled samples. This indicates that cracks were probably developed and propagated very slowly in the material under the influence of the radiation and/or other environmental effects and relatively low stresses and/or stress intensity factors. This "slow crack growth" property of Tenon material has never been studied. C1 NASA, GSFC, Unisys Fed Syst, Mat Engn Branch, Greenbelt, MD 20771 USA. RP Wang, L (reprint author), NASA, GSFC, Unisys Fed Syst, Mat Engn Branch, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 594 EP 606 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500056 ER PT B AU He, C Townsend, JA AF He, C Townsend, JA BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Solar absorption of the FEP samples returned from the HST servicing missions SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE Hubble Space Telescope (HST); fluorinated ethylene propylene (FEP); solar absorption AB The solar absorption of several fluorinated ethylene propylene (FEP) samples that were retrieved from two Bubble Space Telescope Servicing Missions (SMs), was measured to assess the effect of the space environment on the optical properties of the material. The solar absorptance of the silver/FEP on the Cryo Vent Cover retrieved from the HST Second Servicing Mission (HST SM2) was significantly higher than that of the same type of FEP from the First Servicing Mission (HST SM1), the Long Duration Exposure Facility (LDEF) Mission and the Solar Max Mission. Crazing of the silver coating and darkening of the adhesive beneath the coating are the major causes of the absorption increase. The aluminum coating on the aluminum/FEP samples retrieved from the HST SMI and SM2 was found to be crazed and delaminated. The Al/FEP samples from both SM1 and SM2 showed an increase in solar absorptance compared to pristine samples but there was large scatter in the measurements due to non-uniform crazing and delamination of the aluminum coating. The crazing of the aluminum coating and the degradation of the FEP are responsible for the solar absorptance increase. The solar absorption of the FEP itself (Al coating removed) increased for both SM1 and SM2 samples. C1 NASA, Goddard Space Flight Ctr, Unisys Fed Syst, Greenbelt, MD 20771 USA. RP He, C (reprint author), NASA, Goddard Space Flight Ctr, Unisys Fed Syst, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 607 EP 615 PG 9 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500057 ER PT B AU Dever, JA Townsend, JA Gaier, JR Jalics, AI AF Dever, JA Townsend, JA Gaier, JR Jalics, AI BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Synchrotron VUV and soft x-ray radiation effects on aluminized Teflon((R)) FEP SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE synchrotron vacuum ultraviolet and soft x-ray radiation; Teflon((R)) degradation AB Surfaces of the aluminized Teflon(R) FEP multi-layer thermal insulation on the Hubble Space Telescope (HST) were found to be cracked and curled in some areas at the time of the second servicing mission in February 1997, 6.8 years after HST was deployed in low Earth orbit (LEO). As part of a test program to assess environmental conditions which would produce embrittlement sufficient to cause cracking of Teflon(R) on HST, samples of Teflon(R) FEP with a backside layer of vapor deposited aluminum were exposed to vacuum ultraviolet (VUV) and soft x-ray radiation of various energies using facilities at the National Synchrotron Light Source, Brookhaven National Laboratory. Samples were exposed to synchrotron radiation of narrow energy bands centered on energies between 69 eV and 1900 eV. Samples were analyzed for ultimate tensile strength and elongation. Results will be compared to those of aluminized Teflon(R) FEP retrieved from HST after 3.6 years and 6.8 years on orbit and will be referenced to estimated HST mission doses of VUV and soft x-ray radiation. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Dever, JA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 616 EP 628 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500058 ER PT B AU Chamis, CC AF Chamis, CC BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Thermostructural approach for low cost fabrication processing SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE ice forming; casting; mold filling AB A new approach is described which is based on adapting coupled thermal/structural computer codes for low cost fabrication processing. The coupled thermal structural behavior is simulated by using a coupled multidisciplinary computer code. Through this approach the temperature gradients during processing and the respective evolution of thermomechanical properties during cooling are simultaneously evaluated. The approach is demonstrated by applying it to ice forming and casting process to fabricate a simple and a complex component. The volume of the part and its respective mold is modeled by 3-D mixed field finite elements which accommodates solidification, heat transfer, stress/structural analysis. Results obtained show that the temperature gradients are functions of the pouring ports and built-up rapidly in the mold reaching magnitudes approaching those of the melt. The approach is amenable to formal optimization for mold material and multiple pouring ports in order to minimize the thermal gradients which reduce residual stresses and thereby increase part service life. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chamis, CC (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 665 EP 677 PG 13 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500062 ER PT B AU Weiser, ES Baillif, FF Grimsley, BW Marchello, JM AF Weiser, ES Baillif, FF Grimsley, BW Marchello, JM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI High temperature structural foam SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE polymer foam; low density structural foam; thermoplastic; polyimide AB The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 degrees C to 220 degrees C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 degrees C. Certain polyimide foams have moduli of elasticity as high as 0.19 Mpa, with tensile strengths of 3.7 MPa and compressive strengths of 3.6 Mpa, however, they cannot withstand liquid hydrogen temperatures. Other polyimide foams withstand temperatures from -250 degrees C to 200 degrees C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Weiser, ES (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 730 EP 744 PG 15 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500068 ER PT B AU Townsend, JA Hansen, PA McClendon, MW Dever, JA Triolo, JJ AF Townsend, JA Hansen, PA McClendon, MW Dever, JA Triolo, JJ BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Evaluation and selection of replacement thermal control materials for the hubble space telescope SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE low earth orbit (LEO) simulated environments; Teflon (R) FEP (fluorinated ethylene propylene); thermal control materials AB The mechanical and optical properties of the metallized Teflon(R) FEP thermal control materials on the Hubble Space Telescope (HST) have degraded over the nearly seven years the telescope has been in orbit Given the damage to the outer layer of the multi-layer insulation (MLI) that was apparent during the second servicing mission (SM2), the decision was made to replace the outer layer during subsequent servicing missions. A Failure Review Board was established to investigate the damage to the MLI and identify a replacement material. The replacement material had to meet the stringent thermal requirements of the spacecraft and maintain structural integrity for at least ten years. Ten candidate materials were selected and exposed to ten-year HST-equivalent doses of simulated orbital environments. Samples of the candidates were exposed sequentially to low and high energy electrons and protons, atomic oxygen, x-ray radiation, ultraviolet radiation and thermal cycling. Following the exposures, the mechanical integrity and optical properties of the candidates were investigated using Optical Microscopy, Scanning Electron Microscopy (SEM), and a Laboratory Portable Spectroreflectometer (LPSR). Based on the results of these simulations and analyses, the FRB selected a replacement material and two alternates that showed the highest likelihood of providing the requisite thermal properties and surviving for ten years in orbit. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Townsend, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 968 EP 982 PG 15 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500091 ER PT B AU Fay, CC Stoakley, DM St Clair, AK AF Fay, CC Stoakley, DM St Clair, AK BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Molecularly oriented polymeric thin films for space applications SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE molecular orientation; colorless polyimides; space applications; cryogenic treatment AB The increased commitment from NASA and private industry to the exploration of outer space and the use of orbital instrumentation to monitor the earth has focused attention on organic polymeric materials for a variety of applications in space. Some polymeric materials have exhibited short-term (3-5 yr) space environmental durability; however, future spacecraft are being designed with lifetimes projected to be 10-30 years. This gives rise to concern that material property change brought about during operation may result in unpredicted spacecraft performance. Because of their inherent toughness and flexibility, low density, thermal stability, radiation resistance and mechanical strength, aromatic polyimides have excellent potential use as advanced materials on large space structures. Also, there exists a need for high temperature (200-300 degrees C) stable, flexible polymeric films that have high optical transparency in the 300-600nm range of the electromagnetic spectrum. Polymers suitable for these space applications were fabricated and characterized. Additionally, these polymers were molecularly oriented to further enhance their dimensional stability, stiffness, elongation and strength. Both unoriented and oriented polymeric thin films were also cryogenically treated to temperatures below -184 degrees C to show their stability in cold environments and determine any changes in material properties. C1 NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. RP Fay, CC (reprint author), NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 1178 EP 1189 PG 12 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500110 ER PT B AU Munafo, PM AF Munafo, PM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI The problem of fusion zone re-liquation during repair welding of 2195 aluminum alloy SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE aluminum lithium; welding; aerospace AB The problem of cracking during repair welding of 2195 aluminum lithium alloy is addressed. 2195 alloy is the primary structural material in the Super Lightweight Tank, which is being developed to enable a critical upgrade of the Space Shuttle System. Two cracking mechanisms are shown to be in operation: fusion zone re-liquation, a metallurgical effect; and short-time creep/rupture, a mechanical effect. Activities directed toward mitigating both mechanisms are described. The cracking is attributed to the existence of a heavy network of low-melting precipitates in and near the weld. Fusion zone re-liquation occurs primarily at the interface between the original weld and the parent metal; it is best addressed by filler metal selection, employing a strategy of "eutectic crack healing". 4043 is shown to be the best commercially available filler wire for this purpose. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Munafo, PM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 1195 EP 1204 PG 10 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500112 ER PT B AU Winfree, WP Parker, FR Cmar-Mascis, NA AF Winfree, WP Parker, FR Cmar-Mascis, NA BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Imaging corrosion in aircraft structures with reverse geometry X-ray SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn AB The application of reverse geometry x-ray to the detection and characterization of corrosion in aircraft structures is presented. Reverse geometry x-ray is an unique system for real time radiographic imaging of a structure. This system has several possible advantages compared to conventional radiography. First, the x-ray detector can be miniaturized and easily positioned inside a complex structure (such as aircraft wings) enabling images of each surface of the structure to be obtained separately. Second, multiple detectors enable the simultaneous acquisition of data from several different perspectives without moving the structure or the measurement system. This provides a means for locating the position of flaws and enhances separation of features from the surface from features inside the structure. Data is presented on specimens fabricated to simulate corrosion in aircraft structures. The data from multiple detectors is demonstrated to be capable of separating surface features from corrosion in the lap joint and locating the corrosion in multilayer structures. A method is presented for calibration of the detectors to enable quantification of the corrosion to within 2%. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winfree, WP (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 1438 EP 1447 PG 10 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500136 ER PT B AU Banks, BA de Groh, KK AF Banks, BA de Groh, KK BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Ground laboratory soft x-ray durability evaluation of aluminized Teflon FEP thermal control insulation SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE x-ray degradation of Teflon FEP; mechanical properties AB Metallized Teflon fluorinated ethylene propylene (FEP) thermal control insulation is mechanically degraded if exposed to a sufficient fluence of soft x-ray radiation. Soft x-ray photons (4-8 Angstrom in wavelength or 1.55 - 3.2 keV) emitted during solar flares have been proposed as a cause of mechanical properties degradation of aluminized Teflon FEP thermal control insulation on the Hubble Space Telescope (HST). Such degradation can be characterized by a reduction in elongation-to-failure of the Teflon FEP. Ground laboratory soft x-ray exposure tests of aluminized TefIon FEP were conducted to assess the degree of elongation degradation which would occur as a result of exposure to soft x-rays in the range of 3-10 keV. Tests results indicate that soft x-ray exposure in the 3-10 keV range, at mission fluence levels, does not alone cause the observed reduction in elongation of flight retrieved samples. The soft x-ray exposure facility design, mechanical properties degradation results and implications will be presented. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Banks, BA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 1523 EP 1533 PG 11 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500145 ER PT B AU Costen, RC Marchello, JM AF Costen, RC Marchello, JM BE Kliger, HS Rasmussen, BM Pilato, LA Tolle, TB TI Start- on-the- part transient model for in-situ automated tape placement of thermoplastic composites SO 43RD INTERNATIONAL SAMPE SYMPOSIUM AND EXHIBITION ON MATERIALS AND PROCESS AFFORDABILITY - KEYS TO THE FUTURE, VOL 43 LA English DT Proceedings Paper CT 43rd International SAMPE Symposium and Exhibition on Materials and Process Affordability - Keys to the Future CY MAY 31-JUN 04, 1998 CL ANAHEIM, CA SP Soc Adv Mat & Proc Engn DE modeling; carbon fibers; thermoplastic polymers; composites; PEEK/C AB Fabrication of a complex part by automated tape placement (ATP) can require starting up a new tape-end in the part interior, termed "start-on-the-part." Careful thermal management of the starting transient is needed to achieve uniform crystallinity and inter-laminar weld strength -- which is the objective of this modeling effort. The transient is modeled by a Fourier-Laplace transform solution of the time-dependent thermal transport equation in two spatial dimensions. The solution is subject to a quasi-steady approximation for the speed and length of the consolidation head. Sample calculations are done for the Langley ATP robot applying PEEK/carbon fiber composite and for two upgrades in robot performance. The head starts out almost at rest - which meets an engineering requirement for accurate placement of the new tape-end. The head then rapidly accelerates until it reaches its steady state speed. This rapid acceleration, however, violates the quasi-steady approximation, so uniform weld strength and crystallinity during the starting transient are not actually achieved. The solution does give the elapsed time and distance from start-up to validity of the quasi-steady approximation -- which quantifies the length of the non-uniform region. The elapsed time was always less than 0.1 s and the elapsed distance less than 1 cm. This quantification would allow the non-uniform region to be either trimmed away or compensated for in the design of a part. Such compensation would require experiments to measure the degree of non-uniformity, because the solution does not provide this information. The rapid acceleration suggests that the consolidation roller or belt be actively synchronized to avoid abrading the tape. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Costen, RC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-79-4 PY 1998 BP 2005 EP 2019 PG 15 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA BL49K UT WOS:000075698500195 ER PT B AU Ghaffarian, R Kim, NP AF Ghaffarian, R Kim, NP GP EIA EIA TI Reliability and failure analyses of thermally cycled Ball Grid Array assemblies SO 48TH ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE - 1998 PROCEEDINGS SE PROCEEDINGS - ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE LA English DT Proceedings Paper CT 48th Electronic Components & Technology Conference CY MAY 25-28, 1998 CL SEATTLE, WA SP IEEE, Components Packaging Mfg Technol Soc, Electr Ind Assoc AB Reliability of Ball Grid Arrays was assessed as part of a consortium effort led by the Jet Propulsion Laboratory. Nearly 200 test vehicles, each with four packages, were assembled and tested using an experiment design. The most critical variables incorporated in for the experiment were package types, ceramic and plastic; board materials, FR-4 and polyimide; surface finishes, OSP, HASL, and Ni/Au; solder volumes, low, standard, and high; and environmental conditions. Thermal cycling test results to 3,000 cycles for ceramic packages with 625 I/Os and depopulated full array plastic packages with 313 I/Os were presented in a previous paper([1]). This paper will present the most current thermal cycling test results (>6,000 cycles) for plastic OMPAC and SuperBGA packages with 352 I/Os and 560 I/Os. Failure mechanisms detected by electrical continuity interruptions as well as optical and scanning electron microscopy results will also be compared for ceramic and plastic package assemblies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ghaffarian, R (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4526-6 J9 P ELECTR C PY 1998 BP 713 EP 720 DI 10.1109/ECTC.1998.678777 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA BL14K UT WOS:000074438800113 ER PT S AU Hua, XM Kazanas, D Cui, W AF Hua, XM Kazanas, D Cui, W BE Holt, SS Kallman, TR TI Frequency dependent lags - A common phenomenon of accreting sources SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB The Fourier frequency dependent herd X-ray lag, first discovered from the analysis of aperiodic variability of the light curves of the black hole candidate Cygnus X-l, turns out to be a property shared by several other accreting compact sources. We show that the lag can be explained in terms of Comptonization process in coronae of hot electrons with inhomogeneous density distributions. The density profile of a corona, like the optical depth and electron temperature, can significantly affect the Comptonization energy spectrum from it. This means, by fitting the energy spectrum alone, it is not possible to uniquely determine the optical depth and temperature of the Comptonization cloud if its density profile is unknown. The hard X-ray time lag is sensitive to the density distribution of the scattering corona. Thus simultaneous analysis of the spectral and temporal X-ray data will allow us to probe the density structure of the Comptonizing corona and thereby the dynamics of mass accretion onto the compact object. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Hua, XM (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 108 EP 112 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300012 ER PT S AU Kazanas, D Hua, XM AF Kazanas, D Hua, XM BE Holt, SS Kallman, TR TI Modeling the time variability of Black Hole Candidates SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We present model light curves, Power Spectral Densities (PSD) and time lags of accreting Black Hole Candidates (BHC) based on a recent model of these sources. According to our model the observed variability is due, to a large extent, to the stochastic nature of Comptonization, the basic process responsible also for the emission of high energy radiation. Our additional assumption is that the Comptonization process takes place in an extended but non-uniform atmosphere around the compact object. Our model reproduces the observed light curves well, in that it provides a good fit to the PSDs and the overall light curve morphology, indicating, in accordance with observation, that most of the power resides at time scales greater than or similar to a few seconds while at the same time one can distinguish shots of a few msec in duration. We suggest that refinement of this type of model along with spectral and phase lag information can be used to probe the structure of this class of high energy sources. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 113 EP 116 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300013 ER PT S AU Hubeny, I Hubeny, V AF Hubeny, I Hubeny, V BE Holt, SS Kallman, TR TI Non-LTE models and theoretical spectra of accretion disks in Active Galactic Nuclei SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We present self-consistent models of the vertical structure and emergent spectrum of AGN accretion disks. The central object is assumed to be a supermassive Kerr black hole. We demonstrate that non-LTE effects and the effects of a self-consistent vertical structure of a disk play a very important role in determining the emergent radiation, and therefore should be taken into account. In particular, non-LTE models exhibit a largely diminished H I Lyman discontinuity, and strong emission in the He II Lyman discontinuity. Consequently, the number of ionizing photons in the He II Lyman continuum predicted by non-LTE disk models is by 1 - 2 orders of magnitude higher than that following from the black-body approximation. We have also shown that metal line opacities are very important in predicting emergent spectra from AGN disks. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hubeny, I (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 171 EP 174 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300024 ER PT S AU Madejski, G AF Madejski, G BE Holt, SS Kallman, TR TI Broad-band X-ray and gamma-ray continua of Active Galactic Nuclei SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB This paper reviews the X-ray and gamma-ray observations of active galactic nuclei, and summarizes the currently popular models for the radiative processes in these objects. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Madejski, G (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 179 EP 190 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300026 ER PT S AU Yaqoob, T McKernan, B AF Yaqoob, T McKernan, B BE Holt, SS Kallman, TR TI A simple new method for analysing gapped time-series: Power spectrum of MCG -6-30-15 SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We present a new, simple method for analysing gapped time-series which is particularly suited to probe the X-ray power spectra of active galactic nuclei (AGN). The method is applied to a four-day observation of the Seyfert 1 galaxy MCG -6-30-15 with ASCA. MCG -6-30-15 is well-known for rapid, large amplitude X-ray variability. In this source, our method probes the power spectrum in the range 10(-3) Hz to > 5 x 10(-2) Hz, thus extending the high-frequency coverage by a factor of over 50 compared to previous studies. The ASCA data are consistent with a power-law power spectrum with index similar to -1.4, implying a simple extrapolation from the power spectrum measured by EXOSAT at lower frequencies. The data argue against orbital modulation as the origin of the variability since it would imply upper limits on the mass of the putative black hole of less than 5 x 10(5) M., and therefore super-Eddington luminosities. Researchers are encouraged to use the new method on their ASCA, BeppoSAX and archival data. We also propose a new interpretation of the deep minimum in intensity at the end of the long observation of MCG -6-30-15 in terms of an occultation by optically thick matter. If this interpretation is correct, the data allow for the first time, a crude spatial resolution of the X-ray source and possibly of the innermost regions of the putative accretion disk. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Yaqoob, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 223 EP 226 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300035 ER PT S AU Swank, J Chen, XM Markwardt, C Taam, R AF Swank, J Chen, XM Markwardt, C Taam, R BE Holt, SS Kallman, TR TI Disk and corona instabilities in GRS 1915+105 SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We present time-resolved GRS 1915+105 energy and power spectra observed by RXTE, during an episode where the X-ray intensity makes an extreme dip. If the spectra are modeled in terms of disk and power law components, both have large variations. When the inner disk is disrupted, the power law dominates, exhibiting quasi-periodic oscillations with varying frequency until the inner disk returns. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Swank, J (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 327 EP 330 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300053 ER PT S AU Focke, W Swank, J AF Focke, W Swank, J BE Holt, SS Kallman, TR TI Shot distributions from Cygnus X-1 SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB Cygnus X-1 was observed with the Rossi X-Ray Timing Explorer in December 1996. Light curves from this observation have been analyzed in the context oi shot noise models. A peak detection algorithm was applied in order to isolate individual shots. Distributions of some parameters of the shots are investigated. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Focke, W (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 343 EP 346 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300057 ER PT S AU Yu, W Zhang, SN Harmon, BA Paciesas, WS Robinson, CR Grindlay, JE Bloser, P Barret, D Ford, EC Tavani, M Kaaret, P AF Yu, W Zhang, SN Harmon, BA Paciesas, WS Robinson, CR Grindlay, JE Bloser, P Barret, D Ford, EC Tavani, M Kaaret, P BE Holt, SS Kallman, TR TI X-ray bursts from 4U 1608-52 and the associated low frequency noise SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB Three type I X-ray bursts and one burst candidate from 4U 1608-52 were observed with RXTE on March 22, 1996. Between the two strongest bursts, an enhanced noise component below 0.01 Hz was observed in the X-ray light curve with RXTE/PCA. It is probably caused by the subsequent time-dependent nuclear burning after the main X-ray burst. This supports the idea that there is a correlation between the Very-Low-Frequency-Noise (VLFN) in Low-Mass X-ray Binaries (LMXBs) and the nuclear burning. Assuming that the time scale of the variations is the time scale for one fire to ignite another, our result suggests the burning front was propagating at less than 3.0x10(4) cm s-1 on the neutron star surface. C1 George C Marshall Space Flight Ctr, Huntsville, AL 35810 USA. RP Yu, W (reprint author), George C Marshall Space Flight Ctr, Huntsville, AL 35810 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 393 EP 396 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300065 ER PT S AU Strohmayer, TE AF Strohmayer, TE BE Holt, SS Kallman, TR TI RXTE observations of GX 3+1 SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We report on new RXTE observations to search for millisecond X-ray variability from the bright Galactic bulge X-ray source GX 3+1. Although kilohertz quasiperiodic oscillations (QPO) have been detected now in 14 low mass X-ray binary (LMXB) systems they have, somewhat mysteriously, not yet been seen in the bright, persistent, Galactic bulge sources; GX 3+1, GX 9+1, GX 9+9 and GX 13+1. These systems have been typically classified as atoll sources and when bright are seen on the banana or upper banana branch in the X-ray color color diagram. During our observations the source was also in a banana state and we did not detect kHz QPO. We place an upper limit on the amplitude of kHz QPO of about 1% rms. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 397 EP 400 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300066 ER PT S AU Pereyra, NA Kallman, TR Blondin, JM AF Pereyra, NA Kallman, TR Blondin, JM BE Holt, SS Kallman, TR TI Hydrodynamic models of line-driven accretion disk winds in cataclysmic variables SO ACCRETION PROCESSES IN ASTROPHYSICAL SYSTEMS: SOME LIKE IT HOT! SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 8th Astrophysics Conference on Accretion Processes in Astrophysical Systems - Some Like It Hot CY OCT, 1997 CL COLLEGE PK, MD AB We present one-dimensional isothermal analytic hydrodynamic models, both one-dimensional and two-dimensional isothermal numerical models, and twodimensional adiabatic alpha disk numerical models for line-driven accretion disk winds from CVs. Using the one-dimensional analytic models we explore the physical conditions necessary for the existence of a disk wind. Using the two-dimensional isothermal model we explore the effects of centrifugal forces in the wind, and show that these forces cause the wind stream lines to collide producing enhanced density regions in the disk wind. For disk luminosity L-disk. = L., white dwarf mass M-wd = 0.6M., and white dwarf radii R-wd = 0.01R., through the two-dimensional adiabatic alpha disk model we obtain a wind mass-loss rate of 8 x 10(-12)M.yr(-1), a terminal velocity of similar to 3000 km s(-1), and line profiles for CN (1550 Angstrom) for various angles. The line profiles obtained are consistent with observations in their general form and strong dependence in inclination angle. Thus we are able to predict the general observed wind properties of CVs. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Pereyra, NA (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-767-7 J9 AIP CONF PROC PY 1998 IS 431 BP 471 EP 474 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL29Y UT WOS:000075033300079 ER PT S AU Liebe, CC Brown, K Udomkesmalee, S Padgett, C Brenner, M Howard, A Wysocky, T Brown, D Suddarth, S AF Liebe, CC Brown, K Udomkesmalee, S Padgett, C Brenner, M Howard, A Wysocky, T Brown, D Suddarth, S BE Masten, MK Stockum, LA TI VIGIL - a GPS based target-tracking system SO ACQUISITION, TRACKING, AND POINTING XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Acquisition, Pointing, and Tracking CY APR 15-16, 1998 CL ORLANDO, FL SP SPIE AB The VIGILANTE project is a planned vision system capable of tracking and recognizing targets in real time, on a small airborne platform. The project consists of two parts, 1) the Viewing Imager/Gimballed Instrumentation Laboratory (VIGIL), which is an infrared and visible sensor platform with appropriate optics and 2) the Analog Neural Three-dimensional processing Experiment (ANTE), a massive parallel, neural based, high-speed processor. The VIGIL platform is mounted on a helicopter equipped with Global Position System (GPS), Inertia Measurement Unit (IMU), gimbal, radio-link and anti-vibration platform. Also, a jet powered, radio controlled VIGILANTE Target Vehicle (VTV) has been manufactured and equipped with GPS. In the first stages of the project, the VIGIL system is used to acquire image sequences of the VTV for training and testing of the ANTE image recognition processor. Based on GPS and IMU input, the gimbal is pointed toward the VTV and acquires images. This paper describes the VIGIL system in detail. It discusses position-based pointing, tracking algorithms and the alignment procedure. Test imagery and an evaluation of the system will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2814-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3365 BP 10 EP 21 DI 10.1117/12.317509 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL55F UT WOS:000075850600002 ER PT S AU Duren, R Wong, E Breckenridge, B Shaffer, S Duncan, C Tubbs, E Salomon, P AF Duren, R Wong, E Breckenridge, B Shaffer, S Duncan, C Tubbs, E Salomon, P BE Masten, MK Stockum, LA TI Metrology, attitude, and orbit determination for spaceborne interferometric synthetic aperture radar SO ACQUISITION, TRACKING, AND POINTING XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Acquisition, Pointing, and Tracking CY APR 15-16, 1998 CL ORLANDO, FL SP SPIE DE metrology; attitude determination; orbit determination; spacecraft guidance and control; IFSAR AB The Shuttle Radar Topography Mission (SRTM), scheduled for an 11 day Space Shuttle flight in 1999, will use an Interferometric Synthetic Aperture Radar (IFSAR) instrument to produce a near-global digital elevation map of the earth's land surface with 16 m absolute vertical height accuracy at 30 meter postings. SRTM will achieve the required interferometric baseline by extending a receive-only radar antenna on a 60 meter deployable mast from the shuttle payload bay. Continuous measurement of the interferometric baseline length, attitude, and position is required at the 2 mm, 9 arcsec, and 1 m (1.6 sigma) levels, respectively, in order to obtain the desired height accuracy. The Attitude and Orbit Determination Avionics (AODA) subsystem will provide these functions for SRTM. The AODA flight sensor complement includes electro-optical metrology sensors, a star tracker, an inertial reference unit, GPS receivers, plus supporting electronics and computers. AODA ground processing computers will support SRTM system performance evaluation during the mission and baseline reconstruct:ion after the mission. The final AODA data products will be combined with the radar data (range and interferometric phase) to reconstruct the height information necessary for topographic map generation. A description of the AODA system architecture, error budgets, and the major issues involved with measuring large space structures are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Duren, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 198-B9, Pasadena, CA 91109 USA. NR 0 TC 4 Z9 4 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2814-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3365 BP 51 EP 60 DI 10.1117/12.317529 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL55F UT WOS:000075850600006 ER PT J AU Homick, JL Delaney, P Rodda, K AF Homick, JL Delaney, P Rodda, K TI Overview of the Neurolab Spacelab mission SO ACTA ASTRONAUTICA LA English DT Article AB Neurolab is a NASA Spacelab mission with multinational cooperative participation that is dedicated to research on the nervous system. The nervous systems of all animal species have evolved in a one-g environment and are functionally influenced by the presence of gravity. The absence of gravity presents a unique opportunity to gain new insights into basic neurologic functions as well as an enhanced understanding of physiological and behavioral responses mediated by the nervous system. The primary goal of Neurolab is to expand our understanding of how the nervous system develops, functions in, and adapts to microgravity space flight. Twenty-six peer reviewed investigations using human and nonhuman test subjects were assigned to one of eight science discipline teams, individual and integrated experiments within these teams have been designed to collect a wide range of physiological and behavior data in flight as well as pre- and postflight. Information from these investigations will be applicable to enhancing the well being and performance of future long duration space travelers, will contribute to our understanding of normal and pathological functioning of the nervous system, and may be applied by the medical community to enhance the health of humans on Earth. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Homick, JL (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SD, Houston, TX 77058 USA. NR 4 TC 3 Z9 4 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1998 VL 42 IS 1-8 SI SI BP 69 EP 87 DI 10.1016/S0094-5765(98)00107-6 PG 19 WC Engineering, Aerospace SC Engineering GA 113KH UT WOS:000075549800008 PM 11541633 ER PT S AU Jones, WV AF Jones, WV BE Riedler, W Torkar, K TI The challenge to balloon science SO ACTIVE EXPERIMENTS IN SPACE PLASMAS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs AB A thorough review of the NASA balloon program in 1995 confirmed both the inherent importance of balloon science investigations and their value for developing technology for future space missions. A follow-on study in 1996 looked into restructuring the entire suborbital program, in order to find more efficient and effective ways of doing business. These studies were mandated by the adverse impact of NASA's declining budgets and work force constraints on all aspects of space research. The challenge is to accomplish more with less. The balloon program began stepping up to this challenge several years ago with the advent of 10 - 20 day long-duration flights in Antarctica. We must now push ahead with enhanced flight capabilities and with new science instrument technologies, as we forge alliances with other modes of low-cost access to space. Specifically, the development of sealed superpressure balloons could extend flight duration by another order of magnitude, to about 100 days, making ballooning even more competitive with space missions. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA Headquarters, Off Space Sci, Washington, DC 20546 USA. RP Jones, WV (reprint author), NASA Headquarters, Off Space Sci, Code SR, Washington, DC 20546 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043460-6 J9 ADV SPACE RES PY 1998 VL 21 IS 7 BP 921 EP 929 DI 10.1016/S0273-1177(97)01076-4 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL02N UT WOS:000074073000001 ER PT S AU Raque, SM Simpson, JM AF Raque, SM Simpson, JM BE Riedler, W Torkar, K TI Automated pressure control in pressurized balloon systems SO ACTIVE EXPERIMENTS IN SPACE PLASMAS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs AB Efforts of the NASA Long Duration Balloon Vehicle (LDBV) Project to produce a mid-latitude capable, long duration balloon have centered on pressurized systems, Recent nights have shown that large systems, using Overpressurized Zero Pressure (OZP) balloons, have significant performance advantages over their zero pressure brethren. The absence of ducts on these systems requires venting of excess lifting gas through an apex valve. The valve is also used for venting during float to limit pressures in the polyethylene structure. Close pressure control is required on these systems because limit pressures are critical to balloon viability. To limit the amount of human commanding and attention required to operate the LDBV system, automated valving controls are required A simple, two-state control algorithm was tested successfully during flights 342N sind 365N from Lynn Lake, Manitoba Subsequently, a fully automated ascent and float control was successfully employed on night 393NT from Fort Sumner, New Mexico, This paper presents the analysis and flight performance of these control algorithms and their software implementation. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. RP Raque, SM (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 9 TC 1 Z9 2 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043460-6 J9 ADV SPACE RES PY 1998 VL 21 IS 7 BP 971 EP 974 DI 10.1016/S0273-1177(97)01081-8 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL02N UT WOS:000074073000006 ER PT S AU Cathey, HM AF Cathey, HM BE Riedler, W Torkar, K TI Scientific balloon effective radiative properties SO ACTIVE EXPERIMENTS IN SPACE PLASMAS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs AB Prediction of the flight performance of a scientific balloon is dependent on the radiative properties of the balloon. To determine its optical properties for use in performance calculations, the balloon must be viewed as a composite structure. Determination of the balloon's effective radiative properties takes into account the shape, the orientation to radiative sources, and the construction of the balloon including film properties, layers of film, and load rapes. A method for determining the effective radiative properties of a scientific balloon, that is independent of the specific constituent materials attributes, has been developed and has been applied to the standard natural shaped balloons utilized in the U.S. NASA Balloon Program. It can be applied to balloons of any size and construction for both terrestrial and planetary balloons. A commercial computer code is used to compute the total thermal radiation environment. The calculation of the effective absorptivity and effective emissivity of the balloon can now be based on the actual measured absorptivity and measured emissivity of the film and the load tapes. This new method accurately accounts for the physics and the non-uniformities of the balloon surface, and dispenses with the need for adjustments that previously required data from numerous flights. A description of the analysis approach, developed method, and results will be presented. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 New Mexico State Univ, Lab Phys Sci, NASA, Goddard Space Flight Ctr,Wallops Flight Facil, Wallops Island, VA 23337 USA. RP Cathey, HM (reprint author), New Mexico State Univ, Lab Phys Sci, NASA, Goddard Space Flight Ctr,Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 8 TC 5 Z9 8 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043460-6 J9 ADV SPACE RES PY 1998 VL 21 IS 7 BP 979 EP 982 DI 10.1016/S0273-1177(97)01084-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL02N UT WOS:000074073000008 ER PT B AU Swank, JH AF Swank, JH BE Scarsi, L Bradt, H Giommi, P Fiore, F TI The Rossi x-ray timing explorer SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB RXTE has been operating for nearly 2 years and is planning the third. The spacecraft performance has been good and the three instruments are operating well. Observations have been made of the range of targets suitable for RXTE, including such different objects as accreting neutron stars and black holes, stellar flares, and supernova remnants. The goals of studying high time resolution and broad energy range and optimising multiwavelength participation are yielding important results. Oscillations found from low-mass X-ray binaries probably are signatures of the spin of the neutron stars and of the shortest orbital periods around the neutron stars. These are constraining neutron star parameters. Oscillation and spectral results from black hole candidates bring into the realm of possibility the possibilities of measuring the spins of the black holes and using X-ray data to test predictions of gravitation theory. Multiwavelength observations are leading to identification of the locations of the X-ray emission regions and, in the case of the microquasars, to understanding of the mechanisms for jet formation. Recently faster observing response than originally planned has made possible some RXTE contributions to identification of gamma-ray bursts. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Swank, JH (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 12 EP 19 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100002 ER PT B AU Corcoran, MF Ishibashi, K Swank, JH Davidson, K Petre, R Viotti, R Schmitt, JHMM AF Corcoran, MF Ishibashi, K Swank, JH Davidson, K Petre, R Viotti, R Schmitt, JHMM BE Scarsi, L Bradt, H Giommi, P Fiore, F TI Rossi-XTE long-term monitoring of Eta Carinae SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB The unstable star eta Carinae is arguably the Galaxy's most massive known star or an extremely peculiar massive binary. We report first results of similar to weekly RXTE monitoring of eta Car during the 1996 Feb - 1997 Jun interval, with daily coverage in 1997 Jun-Jul; this represents the most detailed description of the X-ray emission of this or any other massive star. Our RXTE results show a progressive increase in the average 2-10 keV flux through the observing interval. Most surprisingly, we find peaks in the X-ray lightcurve which occur every 85 +/- 1.2 days. We consider possible causes of the X-ray variations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, Code 6602, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 33 EP 35 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100005 ER PT B AU Strohmayer, TE Swank, JH Zhang, W AF Strohmayer, TE Swank, JH Zhang, W BE Scarsi, L Bradt, H Giommi, P Fiore, F TI The periods discovered by RXTE in thermonuclear flash bursts SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB Oscillations in the X-ray flux of thermonuclear X-ray bursts have been observed with RXTE from at least 6 low-mass binaries, at frequencies from 330 Hz to 589 Hz. There appear to be preferred relations between the frequencies present during the bursts and those seen in the persistent flux. The amplitude of the oscillations can exceed 50 % near burst onset. Except for a systematic increase in oscillation frequency as the burst progresses, the frequency is stable. Time resolved spectra track increases in the X-ray emitting area due to propagation of the burning front over the neutron star surface, as well as radiation driven expansion of the photosphere. The neutron star mass, radius, and distance can be inferred when spectra are compared to theoretical expectations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 129 EP 134 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100022 ER PT B AU Jahoda, K Stark, MJ Strohmayer, TE Zhang, W Morgan, EH Fox, D AF Jahoda, K Stark, MJ Strohmayer, TE Zhang, W Morgan, EH Fox, D BE Scarsi, L Bradt, H Giommi, P Fiore, F TI Peak luminosities of bursts from GROJ1744-28 measured with the RXTE PCA; Italia: wij post 17 two 4s - a one man marching band - got darn bright SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB GRO J1744-28, discovered by BATSE in December 95, is the second neutron star system known to produce frequent accretion powered bursts. The system has been regularly monitored with the RXTE PCA since the peak of the first outburst in January 96 at which time the observed persistent and bursting count rates were similar to 25,000 ct/sec and similar to 150,000 ct/sec, With corresponding instrumental deadtimes of similar to 10% and greater than or equal to 50%. We present a model which allows the reconstruction of the true incident count rate in the presence of enormous deadtime and use the model to derive a history of the peak luminosities and fluences of the bursts as a function of time. During the peak of the January 1996 and January 1997 outbursts, when the persistent emission was greater than or equal to 1 Crab, we infer peak luminosities of similar to 100 times the Eddington luminosity, and a ratio of persistent emission to integrated burst emission of similar to 34. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Jahoda, K (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. RI Jahoda, Keith/D-5616-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 210 EP 215 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100037 ER PT B AU Gotthelf, EV Kaspi, VM AF Gotthelf, EV Kaspi, VM BE Scarsi, L Bradt, H Giommi, P Fiore, F TI X-ray emission from the 63ms radio pulsar PSRJ1105-6107 SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB We have detected significant X-ray emission from the direction of the young radio pulsar PSR J1105-6107 using the ASCA Observatory. The emission shows no evidence of pulsations; the pulsed fraction is less than 31%, at the 90% confidence level. The X-ray emission can be characterized by a power-law spectrum with photon index alpha = 1.8 +/- 0.4, for a neutral hydrogen column density N-H = 7 x 10(21) cm(-2). The unabsorbed 2 - 10 keV flux assuming the power-law model is (6.4 +/- 0.8) x 10(-13) ergs cm(-2) s(-1). The implied efficiency for conversion of spin-down luminosity to ASCA-band emission is (1.6 +/- 0.2) x 10(-3), assuming a distance of 7 kpc to the source. We argue that the X-rays are best explained as originating from a pulsar-powered synchrotron nebula. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Gotthelf, EV (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 261 EP 264 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100049 ER PT B AU Yaqoob, T McKernan, B AF Yaqoob, T McKernan, B BE Scarsi, L Bradt, H Giommi, P Fiore, F TI A simple new method for analysing gapped time-series: X-ray variability of MCG -6-30-15 SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB We present a new, simple method for analysing gapped time-series which is particularly suited to probe the X-ray power spectra of active galactic nuclei (AGN). The method is applied to a four-day observation of the Seyfert 1 galaxy MCG -6-30-15 with ASCA. MCG -6-30-15 is well-known for rapid, large amplitude X-ray variability. In this source, our method probes the power spectrum in the range 10(-3) Hz to > 5 x 10(-2) Hz, thus extending the high-frequency coverage by a factor of over 50 compared to previous studies. The ASCA data are consistent with a power-law power spectrum with index similar to -1.4, implying a simple extrapolation from the power spectrum measured by EXOSAT at lower frequencies. The data argue against orbital modulation as the origin of the variability since it would imply upper limits on the mass of the putative black hole of less than 5 x 10(5) M-circle dot, and therefore super-Eddington luminosities. Researchers are encouraged to use the new method on their ASCA, BeppoSAX and archival data. We also propose a new interpretation of the deep minimum in intensity at the end of the long observation of MCG -6-30-15 in terms of an occultation by optically thick matter. If this interpretation is correct, the data allow for the first time, a crude spatial resolution of the X-ray source and possibly of the innermost regions of the putative accretion disk. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Yaqoob, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 515 EP 518 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100100 ER PT B AU Valinia, A Marshall, FE AF Valinia, A Marshall, FE BE Scarsi, L Bradt, H Giommi, P Fiore, F TI RXTE measurement of the diffuse X-ray emission from the galactic ridge: Implications for the energetics of the interstellar medium SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB The diffuse X-ray emission from the thin disk surrounding the Galactic mid-plane (the so-called Galactic ridge) was measured with RXTE PCA in order to determine the spatial extent, spectral nature, and origin of the emission. Spatial analysis of the emission in the central 30 degrees of the plane in Galactic longitude reveals the presence of a thin component of width approximate to 0 degrees.2 and a broad component that can be approximated as a Gaussian distribution with FWHM of approximate to 8 degrees. The spectrum can be interpreted as the superposition of the two spatial components with differing amount of absorption. Each spatial component can be modelled with a Raymond-Smith plasma component of temperature similar to 2 keV and a power law component with photon index of similar to 2.5. Based on these findings, we argue that the temperature of the hot phase of the Interstellar Medium (ISM) is less than the previously reported values of 5 - 15 keV. We find that a supernova explosion rate of similar to 1 - 5 per century is adequate to power the thermal emission from the ridge. We discuss the origin of the emission in the hard X-ray band in terms of non-thermal bremsstrahlung of accelerated electrons and protons in supernova remnant (SNR) sites. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Valinia, A (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 629 EP 632 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100122 ER PT B AU Marshall, FE Swank, J Valinia, A Corbet, R Takeshima, T Barthelmy, S Robinson, C Kouveliotou, C Connaughton, V Kippen, M Preece, R Bradt, H Levine, A Remillard, R Smith, D Hurley, K AF Marshall, FE Swank, J Valinia, A Corbet, R Takeshima, T Barthelmy, S Robinson, C Kouveliotou, C Connaughton, V Kippen, M Preece, R Bradt, H Levine, A Remillard, R Smith, D Hurley, K BE Scarsi, L Bradt, H Giommi, P Fiore, F TI RXTE observations of GRB afterglows SO ACTIVE X-RAY SKY: RESULTS FROM BEPPOSAX AND RXTE LA English DT Proceedings Paper CT Active X-Ray Sky Conference CY OCT 21-24, 1997 CL ROME, ITALY AB Variable X-ray sources that appear to be the afterglows of the strong gamma-ray bursts GRB 970616 and GRB 970828 have been discovered with the RXTE PCA. First seen less than 4 hours after the burst, the fur from the sources decreased with time. Although near the sensitivity limit of the PCA, the sources are the brightest afterglows yet seen in X-rays. Similar observations of two other bursts did not detect any afterglows. These results are part of a continuing collaboration between RXTE, BATSE, and IPN scientists to rapidly detect X-ray afterglows of bright gamma-ray bursts. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Marshall, FE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82990-3 PY 1998 BP 640 EP 645 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL61F UT WOS:000076009100124 ER PT S AU Dekany, R Brack, G Palmer, D Oppenheimer, BR Hayward, TL Brandl, B AF Dekany, R Brack, G Palmer, D Oppenheimer, BR Hayward, TL Brandl, B BE Bonaccini, D Tyson, RK TI First tip/tilt correction with the Palomar 200 '' adaptive optics system SO ADAPTIVE OPTICAL SYSTEM TECHNOLOGIES, PARTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Adaptive Optical System Technologies CY MAR 23-26, 1998 CL KONA, HI SP SPIE, European So Observ DE adaptive optics; infrared instrumentation; large telescope instrumentation AB During the nights of 18-22 March 1998, the Palomar 200 " adaptive optics (AO) breathed its first breathe of life, closing lock on a natural guide star for the first time. We present telescope results obtained during the initial closed-loop tip/tilt tests of the AO system at the 5m Hale Telescope on Palomar Mountain. Furthermore, we report on the first light results of the Palomar High Angular Resolution Observer (PHARO). Early tip/tilt correction results demonstrate a factor of similar to 1.3 improvement in peak infrared irradiance for several second exposures. The facility AO and PHARO systems are scheduled for a series of engineering runs throughout 1998. Initial closure of the 241 actuator high order natural guide star (NGS) adaptive loop is expected this summer. C1 CALTECH, Jet Prop Lab, Spatial Interferometry Syst Grp, Pasadena, CA 91109 USA. RP Dekany, R (reprint author), CALTECH, Jet Prop Lab, Spatial Interferometry Syst Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 16 Z9 16 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2800-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3353 BP 56 EP 59 DI 10.1117/12.321717 PG 4 WC Optics SC Optics GA BL80V UT WOS:000076793400006 ER PT S AU Redding, D Basinger, S Brack, G Dekany, R Oppenheimer, B AF Redding, D Basinger, S Brack, G Dekany, R Oppenheimer, B BE Bonaccini, D Tyson, RK TI Adaptive optics reconstruction utilizing super-sampled deformable mirror influence functions SO ADAPTIVE OPTICAL SYSTEM TECHNOLOGIES, PARTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Adaptive Optical System Technologies CY MAR 23-26, 1998 CL KONA, HI SP SPIE, European So Observ AB Control laws for an adaptive optics system for the Palomar Mountain Hale Telescope are described. These are derived using a linear matrix model of the optics, which gives the Hartman-sensor centroids and the science camera wavefront as functions of deformable mirror (DM) commands and atmospheric phase. The matrices defining this system can be directly measured from the optics, some at finer spatial resolution than the wavefront sensor can resolve. A minimum-wavefront compensator feeds back both the wavefront sensor centroids and previous DM commands, using the atmospheric covariance to smooth the response at the finer spatial scale. The DM command feedback provides direct observability of waffle, piston and other modes unobservable in the wavefront sensor. Compensator gains can be updated using Kalman filtering techniques to track the evolution of the atmospheric covariance matrix. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Redding, D (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 6 Z9 6 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2800-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3353 BP 543 EP 552 DI 10.1117/12.321711 PG 10 WC Optics SC Optics GA BL80V UT WOS:000076793400060 ER PT S AU Srivastava, D Menon, M AF Srivastava, D Menon, M BE Murarka, SP Eizenberg, M Fraser, DB Madar, R Tung, R TI Carbon nanotubes: Molecular electronic devices and interconnects SO ADVANCED INTERCONNECTS AND CONTACT MATERIALS AND PROCESSES FOR FUTURE INTEGRATED CIRCUITS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advanced Interconnects and Contact Materials and Processes for Future Integrated Circuits CY APR 13-16, 1998 CL SAN FRANCISCO, CA SP Mat Res Soc C1 NASA, Ames Res Ctr, IT Modeling & Simulat Grp, NAS,MRJ, Moffett Field, CA 94035 USA. RP Srivastava, D (reprint author), NASA, Ames Res Ctr, IT Modeling & Simulat Grp, NAS,MRJ, Moffett Field, CA 94035 USA. NR 0 TC 2 Z9 2 U1 0 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-420-3 J9 MATER RES SOC SYMP P PY 1998 VL 514 BP 471 EP 471 PG 1 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Engineering; Materials Science GA BM01U UT WOS:000077430000085 ER PT S AU Downie, JD Timucin, DA Gary, CK Ozcan, M Smithey, DT Crew, M AF Downie, JD Timucin, DA Gary, CK Ozcan, M Smithey, DT Crew, M BE Mitkas, PA Hasan, ZU TI Investigation of bit-error-rate issues for holographic data storage in bacteriorhodopsin films SO ADVANCED OPTICAL MEMORIES AND INTERFACES TO COMPUTER STORAGE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Optical Memories and Interfaces to Computer Storage CY JUL 22-24, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE bacteriorhodopsin; holography; optical data storage AB Photochromic films made from bacteriorhodopsin (BR) possess many desirable characteristics for a candidate holographic optical data storage medium. These properties include optical erasability, high spatial resolution, adequate diffraction efficiency, flexible film formats, durability, an optimal recording/readout wavelength of about 680-690 nm, and potentially inexpensive cost.. In this paper, we experimentally study the raw bit-error-rate (BER) achievable with BR films made from the genetic variant known as D85N. Experimental data is collected for digital bit patterns fabricated as chrome-on-glass masks, at two different spatial resolutions. The results show that films fabricated from D85N have good potential for use in holographic data storage systems, but that further effort must be devoted to the film fabrication process in order to minimize optical nonunifonnity and scattering losses. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Downie, JD (reprint author), NASA, Ames Res Ctr, M-S 269-3, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2923-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3468 BP 195 EP 205 DI 10.1117/12.330418 PG 11 WC Computer Science, Hardware & Architecture; Optics SC Computer Science; Optics GA BM20R UT WOS:000078029300023 ER PT S AU McGrath, WR Skalare, A Karasik, B Gaidis, M Bumble, B LeDuc, HG Burke, PJ Schoelkopf, RJ Prober, DE AF McGrath, WR Skalare, A Karasik, B Gaidis, M Bumble, B LeDuc, HG Burke, PJ Schoelkopf, RJ Prober, DE BE Phillips, TG TI Superconductive hot electron mixers for THz heterodyne receiver applications SO ADVANCED TECHNOLOGY MMW, RADIO, AND TERAHERTZ TELESCOPES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Advanced Technology MMW, Radio, and Terahertz Telescopes CY MAR 26-28, 1998 CL KONA, HI SP SPIE, European So Observ DE submillimeter; heterodyne; mixer; hot electron bolometer; terahertz; superconductor; far infrared AB We report on the development of quasioptical Nb hot-electron bolometer mixers for heterodyne receivers operating at 1 THz - 3 THz. The devices have submicron in-plane sizes, thus exploiting diffusion as the electron cooling mechanism. Quasioptical mixer circuits have been developed with planar double-dipole or twin-slot antennas. The measured (DSB) receiver noise temperatures are 1670 K at 1.1 THz, with an estimated mixer noise temperature of = 1060 K, and 2750 K at 2.5 THz, with an estimated mixer noise temperature of approximate to 900 K. The IF bandwidth is found to scale as the length-squared, and bandwidths as high as 8 GHz have been measured. These results demonstrate the low-noise, broadband operation of the diffusion-cooled bolometer mixer over a wide range of far-infrared wavelengths. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP McGrath, WR (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Mail Stop 168-314,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Gaidis, Michael/D-3327-2013; Burke, Peter/F-3308-2010 NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2804-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3357 BP 14 EP 21 DI 10.1117/12.317341 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL55D UT WOS:000075850400002 ER PT S AU Gaier, T Mehdi, I Kooi, J Fujiwara, B Lai, R AF Gaier, T Mehdi, I Kooi, J Fujiwara, B Lai, R BE Phillips, TG TI A W-band HEMT based power amplifier module for millimeter-wave LO multipliers SO ADVANCED TECHNOLOGY MMW, RADIO, AND TERAHERTZ TELESCOPES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Advanced Technology MMW, Radio, and Terahertz Telescopes CY MAR 26-28, 1998 CL KONA, HI SP SPIE, European So Observ DE power amplifiers; local oscillators; radiometers; LO noise AB We report on the performance of power amplifiers as local oscillator drivers for millimeter and submillimeter-wave receivers. A MMIC power amplifier based on 0.1 micron GaAs HEMT technology on 50 micron thick substrate has been packaged in a waveguide block and characterized. Output power in excess of 100 mW is demonstrated over 88-94 GHz with more Fewer easily achievable. The noise properties of the MMIC amplifier in multiplied local oscillator chains are characterized in a low noise superconductor-insulator-superconductor mixer based heterodyne receiver. A 386 GHz SIS mixer was used to characterize noise temperature in a laboratory environment. A more sensitive measurement of noise contribution from the amplifier was performed on a 278 GHz mixer/receiver at the Caltech Submillimeter-Wave Observatory, during astronomical observations. It is concluded that the MMIC amplifier does not add additional significant noise to the radiometer system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaier, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2804-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3357 BP 114 EP 121 DI 10.1117/12.317344 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL55D UT WOS:000075850400012 ER PT S AU Bock, JJ Glenn, J Grannan, SM Irwin, KD Lange, AE LeDuc, HG Turner, AD AF Bock, JJ Glenn, J Grannan, SM Irwin, KD Lange, AE LeDuc, HG Turner, AD BE Phillips, TG TI Silicon nitride micromesh bolometer arrays for SPIRE SO ADVANCED TECHNOLOGY MMW, RADIO, AND TERAHERTZ TELESCOPES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Advanced Technology MMW, Radio, and Terahertz Telescopes CY MAR 26-28, 1998 CL KONA, HI SP SPIE, European So Observ DE infrared detectors; bolometers; arrays AB We are developing arrays of bolometers based on silicon nitride micromesh absorbers for the Spectral & Photometric Imaging Receiver (SPIRE) on the Far Infra-Red and Submillimeter Space Telescope (FIRST). The bolometers are coupled to a close-packed array of 1 f lambda feedhorns which views the primary mirror through a cooled aperture stop. Feedhorn-coupled bolometers minimize the detector area and throughput and have good optical efficiency. A 1 f lambda feedhorn array provides higher mapping speed than a 2f lambda feedhorn array and reduces the number of jitters required to produce a fully sampled map, but at the cost of more detectors. Individual silicon nitride micromesh bolometers are already able to meet the performance requirements of SPIRE. In parallel we are developing transition-edge detectors read out by a SQUID current amplifier. The relatively large cooling power available at 300 mK enables the array to be coupled to a cold SQUID multiplexer, creating a monolithic fully multiplexed array and making large format arrays possible for SPIRE. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bock, JJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 41 Z9 41 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2804-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3357 BP 297 EP 304 DI 10.1117/12.317365 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL55D UT WOS:000075850400031 ER PT J AU Kaneko, H Noren, RD Padilla, PA AF Kaneko, H Noren, RD Padilla, PA TI Singularity preserving Galerkin method for Hammerstein equations with logarithmic kernel SO ADVANCES IN COMPUTATIONAL MATHEMATICS LA English DT Article DE singularity preserving Galerkin method; Hammerstein equations with logarithmic kernel; iterated singularity preserving Galerkin method ID FREDHOLM INTEGRAL-EQUATIONS; 2ND KIND AB In a recent paper [3], Cao and Xu established the Galerkin method for weakly singular Fredholm integral equations that preserves the singularity of the solution. Their Galerkin method provides a numerical solution that is a linear combination of a certain class of basis functions which includes elements that reflect the singularity of the solution. The purpose of this paper is to extend the result of Cao and Xu and to establish the singularity preserving Galerkin method for Hammerstein equations with logarithmic kernel. The iterated singularity preserving Galerkin method is also discussed. C1 Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 24 TC 6 Z9 7 U1 0 U2 0 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1019-7168 J9 ADV COMPUT MATH JI Adv. Comput. Math. PY 1998 VL 9 IS 3-4 BP 363 EP 376 DI 10.1023/A:1018910128100 PG 14 WC Mathematics, Applied SC Mathematics GA 146MP UT WOS:000077433100006 ER PT S AU Fesmire, JE Rouanet, S Ryu, J AF Fesmire, JE Rouanet, S Ryu, J BE Balachandran, UB Gubser, DG Hartwig, KT Reed, RP Warnes, WH Bardos, VA TI Aerogel-based cryogenic superinsulation SO ADVANCES IN CRYOGENIC ENGINEERING MATERIALS, VOL 44, PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT 12th International Cryogenic Materials Conference (ICMC) CY JUL 28-AUG 01, 1997 CL PORTLAND, OR SP Cabot Performance Mat, Oxford Instruments, Intermagnet Gen Corp AB This paper presents the development of a flexible, easy-to-use superinsulation. The innovative material system employs ultralow density aerogels within a flexible fiber matrix for minimum heat transfer and maximum applicability and durability. The core of the system is aerogels formed at the fiber-fiber contacts of the matrix, forcing solid conduction to occur through the aerogels. This composite configuration improves both the ease of handling aerogels and the overall thermal resistance. The close-packed structure of the aerogels also eliminates the open spaces in the fiber matrix and thereby reduces gas conduction. Excellent thermal resistance was achieved for both evacuated and nonevacuated insulation systems while maintaining structural flexibility. The aerogels were also produced in an opacified fiber matrix. Testing of these composites indicated a significant inhibition of radiation in the infrared range. Thermal performance was measured by transient heat flux and liquid nitrogen boiloff methods. The apparent thermal conductivity of the silica-aerogel/fiber composite was lower than I milliwatt per meter-kelvin (mW/m-K) at a high vacuum level [below 1x10(-5) millibars (mbar)] and below 10 mW/m-K in ambient pressure nitrogen (boundary temperatures were approximately 77 K and 280 K for all tests). Performance was found to be insensitive to residual gas pressure up to a vacuum level of about 1x10(-1) mbar. Aerogel-based superinsulation systems have been produced and tested in blanket, sheet, and clamshell forms for use on a variety of cryogenic equipment. C1 NASA, Kennedy Space Ctr, Engn Dev Directorate, KSC, Kennedy Space Ctr, FL 32899 USA. RP Fesmire, JE (reprint author), NASA, Kennedy Space Ctr, Engn Dev Directorate, KSC, Kennedy Space Ctr, FL 32899 USA. NR 13 TC 3 Z9 3 U1 0 U2 4 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45918-3 J9 ADV CRYOG ENG PY 1998 VL 44 BP 219 EP 226 PN A AND B PG 8 WC Thermodynamics; Materials Science, Multidisciplinary SC Thermodynamics; Materials Science GA BM41R UT WOS:000078666200029 ER PT S AU Miranda, FA Kwok, RS Demo, MS Bohman, DY Fiedziuszko, SJ AF Miranda, FA Kwok, RS Demo, MS Bohman, DY Fiedziuszko, SJ BE Balachandran, UB Gubser, DG Hartwig, KT Reed, RP Warnes, WH Bardos, VA TI Miniaturized multilayer filters with YBa2Cu3O7-delta on LaAlO3 and MgO substrates SO ADVANCES IN CRYOGENIC ENGINEERING MATERIALS, VOL 44, PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT 12th International Cryogenic Materials Conference (ICMC) CY JUL 28-AUG 01, 1997 CL PORTLAND, OR SP Cabot Performance Mat, Oxford Instruments, Intermagnet Gen Corp ID SATELLITE-COMMUNICATIONS AB The need for filter miniaturization without performance degradation has become a critical requirement for the payload of the next generation of communication satellites. Currently, these payloads contain hundreds of filters that are used for frequency multiplexing. Typically these filters consist of dual mode cavities or dielectric filled resonators which generally are large and heavy. An ongoing effort between the Electron Device Technology Branch of the NASA LeRC and Space System/Loral has resulted in a demonstration of a proof-of-concept (POC) C-band YBa2Cu3O7-delta (YBCO) on LaAlO3 multilayer filter with a raw value for the minimum insertion loss of 0.18 dB at 77 K, 3.81 GHz, and similar to 3 W input power. Implementing this dual-mode, four pole filter with gold instead of YBCO resulted in a minimum insertion loss of 3.39 dB at room temperature and of 1.61 dB at 77 K at 3.86 GHz and 10 dBm input power. The volume of this filter is similar to 0.46 cm(3) which is less than 1 percent of the volume of its dielectric counterparts at C-band. The filter was also implemented using MgO substrates, which have a dielectric constant lower than their LaAlO3 counterparts (9.7 versus 24, respectively). For a YBCO on MgO filter, a raw minimum insertion loss of 0.34 dB was measured at 6.09 GHz and 77 K, while its gold counterpart exhibited 1.86 dB and 1.11 dB at 5.98 GHz at room temperature and 77 K, respectively. The advantages and limitations of this novel filter configuration will be discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Miranda, FA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45918-3 J9 ADV CRYOG ENG PY 1998 VL 44 BP 753 EP 759 PN A AND B PG 7 WC Thermodynamics; Materials Science, Multidisciplinary SC Thermodynamics; Materials Science GA BM41R UT WOS:000078666200099 ER PT S AU Yeager, CJ Shirron, PJ DiPirro, MJ AF Yeager, CJ Shirron, PJ DiPirro, MJ BE Kittel, P TI High resolution thermometry using the magnetic penetration depth of superconducting films SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB A Penetration Depth Thermometer (PDT) has been under development for potential use in microgravity critical point experiments. The active element is a superconducting film whose thickness is comparable to the magnetic penetration depth (5-20 nm). Field penetration is strongly temperature dependent just below the transition (similar to 0.9 -1.0 T-c). Fields are generated and sensed by using excitation and pickup coils located near the film. Using a de SQUID sensor for readout, temperature resolution on the order of 0.1 nK/root Hz can be obtained. Earlier work using aluminum films (T-c=1.69 K) demonstrated a maximum sensitivity of 1 nK/root Hz. Improvements in coil design have since yielded a factor of 3 improvement. PDT's have been made with aluminum films deposited on a planar sapphire substrate with transition temperatures greater than the lambda point in superfluid helium. For performance tests, a cryostat has been constructed where the PDT will be in an experimental cell filled with superfluid. This will provide thermal stability better than 0.1 nK/root Hz. Results of the current design are presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yeager, CJ (reprint author), NASA, Goddard Space Flight Ctr, Code 713, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 757 EP 763 PN A AND B PG 3 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800094 ER PT S AU Breon, SR DiPirro, MJ Warner, BA Shirron, PJ Tuttle, JG AF Breon, SR DiPirro, MJ Warner, BA Shirron, PJ Tuttle, JG BE Kittel, P TI Thermal performance of the XRS helium cryostat SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB The Astro-E/X-Ray Spectrometer (XRS) is required to operate for 2 years on-orbit with approximately 20 liters of superfluid helium. The total heat load on the helium must be less than 1 mW, which is significantly smaller than any previous spaceborne helium system. Consequently, the XRS cryostat incorporates several new techniques that have not been used before in spaceborne cryogenic systems, including high temperature superconducting leads, a film flow suppressor in the vent line, and kevlar suspension systems. The thermal design of the cryostat is described and results of the ground tests of both an engineering model cryostat and the flight cryostat are presented. Tests of the flight cryostat are incomplete at the writing of this paper, so only preliminary results are given. C1 NASA, Cryogen Prop & Fluid Syst Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Breon, SR (reprint author), NASA, Cryogen Prop & Fluid Syst Branch, Goddard Space Flight Ctr, Code 713, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 941 EP 948 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800118 ER PT S AU Shirron, PJ DiPirro, MJ AF Shirron, PJ DiPirro, MJ BE Kittel, P TI Suppression of superfluid film flow in the XRS helium dewar SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB Superfluid helium dewars for space missions use a porous plug phase separator to retain the bulk liquid while releasing boiloff vapor. Although the thermomechanical force is quite effective in holding the liquid against the internal vapor pressure, van der Waals forces will lead to a leakage of helium through the porous plug to feed the flow of a superfluid film in the vent line. Since the latent heat is generally not extracted from the remaining Liquid, the film poses a serious problem for space missions such as the X-Ray Spectrometer (XRS) which have extremely low heat load budgets. A design for the XRS porous plug and vent system is presented which keeps film losses below 2 mu g/s through a combination of a heat exchanger, to evaporate the film, and a knife-edge device. Tests of the vent have been conducted in a minus Ig configuration. At the expected on-orbit tank temperature of 1.22 K, film losses are negligible, but rise to 4 mu g/s at the maximum tank temperature of 1.30 K. Design parameters and performance tests are discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Shirron, PJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 15 Z9 15 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 949 EP 956 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800119 ER PT S AU Serlemitsos, AT SanSebastian, M Kunes, ES AF Serlemitsos, AT SanSebastian, M Kunes, ES BE Kittel, P TI Final design of the XRS/Astro-E ADR SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB GSFC has developed an X-Ray Spectrometer (XRS) to be flown aboard Astro-E, in cooperation with the Japanese Institute of Space and Astronomical Science (ISAS). XRS uses an array of 32 microcalorimeters capable of detecting X-rays in the energy range of 0.3-10 keV with a resolution of 12 eV. In order to accomplish this, the detectors must be operated at a temperature of 0.065 K. In space, an Adiabatic Demagnetization Refrigerator (ADR) must be used to cool the detectors to that temperature. A spaceworthy ADR has been developed at GSFC to be used in the XRS. Originally, the ADR was developed to be flown aboard the AXAF(1,2). Budgetary constraints necessitated the move of the XRS to the Astro-E program and this resulted in a considerable reduction in weight and a much tighter thermal specifications for the ADR. The allowable average thermal load of the ADR to the LHe dewar was changed from 2.6 mW to 250 mu W. Time constraints did not allow a complete redesign of the ADR. The original shape and size were left unchanged and the new specifications were met by streamlining the heat switch and lengthening the salt pill magnetization cycle time. Size and weight contraints forced us to abandon the original redundancy plan of having a heat switch on either side of the salt pill. We experimented to provide redundancy by replacing a single heat switch with two much slimmer heat switches occupying the same volume, each with almost half the capacity but also half the parasitic heat leak. They were independent from each other, thus providing redundancy, but could be operated simultaneously so as not to reduce the heat switch capacity significantly. During vibration testing we discovered that the considerable reduction in stiffness made these heat switches vulnerable to shorting. It was, therefore, decided that it was preferable to proceed with a single heat switch without redundancy. For a LHe bath temperature of 1.3 K the gas gap heat switch presently used has an on/off ratio of similar to 28000 and a parasitic heat leak of 2.4 mu W/K. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Serlemitsos, AT (reprint author), NASA, Goddard Space Flight Ctr, Code 713-1, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 5 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 957 EP 963 PN A AND B PG 3 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800120 ER PT S AU Tuttle, JG Hait, TP Boyle, RF Muller, HJ Hodge, JD Breon, SR AF Tuttle, JG Hait, TP Boyle, RF Muller, HJ Hodge, JD Breon, SR BE Kittel, P TI A high Tc superconducting current lead assembly for the XDS helium cryostat SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB The X-ray Spectrometer Detector System (XDS) helium cryostat consists of a tank of pumped liquid helium at about 1.3 kelvin suspended inside a seventeen kelvin cylindrical support structure. The tank is a heat sink for an adiabatic demagnetization refrigerator (ADR) and its superconducting magnet. The cryostat's small initial helium volume and mission lifetime goal of 2.5 years require that the average total heat load to the helium be less than about 800 microwatts. During the mission the superconducting magnet requires a current of 2 amps with a three percent duty cycle. In addition, wires capable of carrying up to 1 amp are needed for cryogenic valve operations during the cryostat's ground servicing. The best optimized conventional current leads between the 17 kelvin stage and the magnet and valves would contribute an average heat load to the helium of about 3 milliwatts. An assembly of superconducting YBaCuO fibers bonded to a fiberglass tube and suspended by a Kevlar braid was developed to conduct the current from the 17 kelvin support structure to a vapor-cooled 4 kelvin stage. NbTi wires provide a superconducting path from the 4 kelvin stage to the magnet and valves on the 1.3 kelvin helium tank. This paper describes the assembly's fabrication and suspension and presents the results of its performance and vibration tests. C1 NASA, Hughes STX Corp, GSFC, Greenbelt, MD 20771 USA. RP Tuttle, JG (reprint author), NASA, Hughes STX Corp, GSFC, Code 713, Greenbelt, MD 20771 USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 965 EP 972 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800121 ER PT S AU Luchik, TS Larson, ME Israelsson, UE Pearson, D Petrac, D Elliott, S AF Luchik, TS Larson, ME Israelsson, UE Pearson, D Petrac, D Elliott, S BE Kittel, P TI Lifetime enhancement of the CHeX cryogenic system SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB The Confined Helium Experiment (CHeX) is manifested for flight on the Space Shuttle (STS-87) in November, 1997. The experiment was constrained to re-use a previously flown flight cryogenic system. However, the inherited system did not meet CHeX science requirements, nor current Shuttle launch requirements; enhancements of the system and procedures were required. We present model and data of the full flight system, before and after the enhancements were made. A discussion of procedural changes and their impact on the system are also presented. With the changes, all Shuttle servicing requirements were met. A net improvement in ground servicing of 30% and a net parasitic reduction of 15% were achieved. Predicted flight performance is also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Luchik, TS (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 PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 989 EP 994 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800124 ER PT S AU Lysek, MJ Israelsson, UE Chui, TCP Larson, ME Petrac, D Elliott, SE Swanson, DR Oin, X Lipa, JA AF Lysek, MJ Israelsson, UE Chui, TCP Larson, ME Petrac, D Elliott, SE Swanson, DR Oin, X Lipa, JA BE Kittel, P TI Design and testing of an improved cryopump for the confined helium experiment SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB A cryopump flown on the space shuttle for the Lambda Point Experiment(1) (LPE) was improved and redesigned for use in the Confined Helium Experiment (CHeX). The successful Lambda Point Experiment (LPE) flew on the space shuttle in October 1992. The Confined Helium Experiment (CHeX) will launch in October 1997. CHeX uses high resolution thermometers(2) to measure the heat capacity of liquid helium when confined within finely spaced parallel disks. To eliminate heat flow between the calorimeter and the cryogenic bath, a cryopump is used to reduce the pressure in the experimental probe. The LPE cryopump trapped activated charcoal behind a nuclepore filter. The new cryopump uses activated charcoal glued to copper plates to eliminate the nuclepore filter. Vibration tests verified that the cryopump does not generate charcoal dust contamination. Early performance tests indicated that the probe vacuum is significantly lower with the new pump, and that the pressure falls more rapidly than with the previous design. Recent tests with the CHeX experimental probe show a significant reduction in the heat leak between the calorimeter and the cryogenic bath. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lysek, MJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 995 EP 1000 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800125 ER PT S AU Bowman, RC Karlmann, PB Bard, S AF Bowman, RC Karlmann, PB Bard, S BE Kittel, P TI Post-flight analysis of a 10 K sorption cryocooler SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB In May 1996, the Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment (BETSCE) was flown aboard the Space Shuttle flight STS-77 in the first space-flight demonstration of chemisorption cryocooler technology. While on orbit, BETSCE successfully met its science objectives of cooling from 70 K to 10 K in less than two minutes, sustaining a 100 mW heat load below 11 K for over ten minutes, and demonstrating recycle times of approximately eleven hours. The hydride compressors were able to circulate and compress the hydrogen refrigerant fluid in a repeatable manner with no adverse microgravity effects being observed. Since completion of the Shuttle flight, the BETSCE flight hardware was carefully inspected and a repair was made to a system valve which had developed an internal leak during flight. A series of successful cooldown cycles to below 9.5 K were completed during post-flight ground tests following repair of this valve. All observed compressor and cryostat parameters obtained in the measurements performed after flight were entirely consistent with the behavior seen in the pre-flight tests. These results verify that key functional performance of the BETSCE instrument is highly reproducible and did not degrade throughout the extensive ground tests and flight operations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bowman, RC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 1017 EP 1024 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800128 ER PT S AU Dipirro, MJ Shirron, PJ McHugh, DC AF Dipirro, MJ Shirron, PJ McHugh, DC BE Kittel, P TI A liquid helium film heat pipe/heat switch SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB We report on the development of a compact, high conductance heat pipe/heat switch using Liquid helium and a wick material. As a heat pipe its operation is similar to that of capillary pumped loop heat pipes except that it is very small. The device is also used as a heat switch by attaching a getter which can be heated. The helium is desorbed from the getter heating to similar to 35K by using a small (< 3mW) power and the switch is then on. The on state conductance of the first device tested was over 400 mW per Kelvin at 1.8K. Unheated, the getter quickly cools and adsorbs enough helium so that the heat switch turns off. For the first device tested the switch turned off at a getter temperature of 24K. The off conductance was 3.5 microwatts per Kelvin at 1.5K. This first version had a maximum heat flow capability of 4 mW. Future switches will be designed for a larger temperature and heat flow operating range and decreased off state conductance. This device was designed to replace gas-gap heat switches currently used in adiabatic demagnetization refrigerators. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dipirro, MJ (reprint author), NASA, Goddard Space Flight Ctr, Code 713, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 1497 EP 1504 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800187 ER PT S AU Ross, RG Johnson, DL AF Ross, RG Johnson, DL BE Kittel, P TI Effect of heat rejection conditions on cryocooler operational stability SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB It is well known that cryocooler thermal efficiency is a strong function of heat rejection temperature, roughly following the dependency described by Carnot. An equally important and generally overlooked implication of cryocooler heat-rejection thermodynamics is the effect of the heat rejection temperature control mode on cryocooler performance and operational stability. Example heat rejection temperature control modes include constant reject temperature (generally maintained via closed-loop temperature control), heat rejection temperature rising linearly with power dissipation (typical of conduction/convection to a constant temperature heat sink), and heat rejection dependent on the fourth power of reject temperature (typical of radiation to deep space). This paper presents a useful algorithm for computing the effect of changing heatsink temperature on cryocooler performance and uses the algorithm to examine the implications of various heat rejection temperature control modes on cryocooler operation. A useful system-level thermal performance map is developed to display the stability boundaries and available stable operating space for coolers of interest for various typical heat rejection control modes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ross, RG (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 PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 1745 EP 1752 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800220 ER PT S AU Roach, PR Kashani, A AF Roach, PR Kashani, A BE Kittel, P TI Pulse tube coolers with an inertance tube: Theory, modeling, and practice SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB We have studied the advantages to be gained by replacing the orifice of a pulse tube cooler with an inertance tube-a long thin tube that introduces the possibility for additional phase shift between pressure and mass flow in the pulse tube section. A case for using an inertance tube is made by employing an electrical analogy, where the 'inductance' added by the inertance tube allows for an improved power transfer efficiency at the cold end of the pulse tube. Detailed computer modeling of pulse tube systems with inertance tubes confirms these advantages. Comparison between a laboratory cooler with an orifice and with two inertance tubes is presented; the inertance tubes yield dramatic improvements over the use of the orifice. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Roach, PR (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 23 Z9 24 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 1895 EP 1902 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800239 ER PT S AU Kittel, P AF Kittel, P BE Kittel, P TI The temperature profile within pulse tubes SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 43 PTS A AND B SE ADVANCES IN CRYOGENIC ENGINEERING LA English DT Proceedings Paper CT Joint Cryogenic Engineering / International Cryogenic Materials Conference CY 1997 CL PORTLAND, OR SP Cabot Performance Mat, Cryogas Int Inc, Int Inst Refrigerat, Oxford Magnet Technol & Oxford Superconductor Technol, NorthW Nat Gas, Wah Chang AB A simple model is developed of the temperature profile within the pulse tube section of Pulse Tube Refrigerators. Using the Lagrangian reference frame, this simplified model directly gives the temperature overshoot at the hot and cold ends. The overshoots are,the result of the interaction of the gas flow and the heat exchangers. They result from the work flow in the gas being converted to heat flow prior to reaching the heat exchangers. The mean temperature overshoot at the hot end is Delta T approximate to (pi)/2 T-1, where T-1 is the amplitude of the temperature oscillation within the pulse tube. At the cold end, the mean temperature overshoot is Delta T approximate to - ((pi)/2) (Q (net)/Q (gross)) T-1, where Q( net) and Q (gross) refer to the net and gross cooling powers respectively. Away from the ends, the temperature gradient is primarily due to thermal conductivity. The temperature overshoot effects are excluded in many models developed in the Eulerian reference frame because these models often explicitly exclude the changes in mean gas temperature that occur at the entrance to the heat exchangers. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kittel, P (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0065-2482 BN 0-306-45807-1 J9 ADV CRYOG ENG PY 1998 VL 43 BP 1927 EP 1932 PN A AND B PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BL67N UT WOS:000076284800243 ER PT B AU Noor, AK AF Noor, AK BE Topping, BHV TI ISE - Intelligent Synthesis Environment for future aerospace systems and its impact on engineering research and education SO ADVANCES IN ENGINEERING COMPUTATIONAL TECHNOLOGY LA English DT Proceedings Paper CT 1st International Conference on Engineering Computational Technology/4th International Conference on Computational Structures Technology CY AUG 18-21, 1998 CL EDINBURGH, SCOTLAND AB The Intelligent Synthesis Environment (ISE) being developed by NASA, the University of Virginia and the Jet Propulsion Laboratory for significantly enhancing the rapid creation of innovative affordable products and missions is described. ISE uses a synergistic combination of leading-edge technologies, including high performance computing, high capacity communications and networking, human-centered computing, knowledge-based engineering, computational intelligence, virtual product development, and product information management. The environment will link scientists, design teams, manufacturers, suppliers, and consultants who participate in the mission synthesis as well as in the creation and operation of the aerospace system. It will radically advance the process by which complex science missions are synthesized, and high-tech engineering systems are designed, manufactured and operated. The five major components critical to ISE and some of their subelements are described; namely, human-centered computing, infrastructure for distributed collaboration, rapid synthesis and simulation tools, life cycle integration and validation, and cultural change in the creative process. Related U.S. government programs are outlined and the future impact of ISE on engineering research and education is discussed. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA USA. NR 0 TC 3 Z9 3 U1 0 U2 2 PU CIVIL COMP PRESS PI EDINBURGH PA 10 SAXE-COBURG PLACE, EDINBURGH EH3 5BR, MIDLOTHIAN, SCOTLAND BN 0-948749-55-5 PY 1998 BP 1 EP 10 PG 10 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods; Engineering, Multidisciplinary SC Computer Science; Engineering GA BL96S UT WOS:000077305500001 ER PT S AU Corp, LA McMurtrey, JE Chappelle, EW Daughtry, CST Kim, MS Mulchi, CL AF Corp, LA McMurtrey, JE Chappelle, EW Daughtry, CST Kim, MS Mulchi, CL BE Narayanan, RM Kalshoven, JE TI Applications of fluorescence sensing systems to the remote assessment of nitrogen supply in field corn (Zea mays L.) SO ADVANCES IN LASER REMOTE SENSING FOR TERRESTRIAL AND HYDROGRAPHIC APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advances in Laser Remote Sensing for Terrestrial and Hydrographic Applications CY APR 13-14, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE fluorescence; remote sensing; nitrogen fertilization; Zea mays L. AB Currently, leaf and canopy level fluorescence measurements are being explored as a means to non-destructively monitor plant productivity. Over the past few decades it has been established that changes in fluorescence characteristics of green vegetation can relate to both anthropogenic and naturally occurring plant stresses. The following studies were conducted to better define changes in fluorescence properties of field grown corn (Zea mays L.) as they relate to varying levels of nitrogen fertilization. Nitrogen was supplied in the form of urea at varying rates to obtain levels corresponding to 150, 125, 100, 75, 50, 25, 0 % of the nitrogen required for optimal growth. The recommended rate for nitrogen fertilization on the field site consisting of a Codrous sandy loam soil was determined by the soil testing laboratory at the University of Maryland to be 162 kg N/ha. The field site consisted of seven nitrogen treatments in four randomized complete blocks. Fluorescence spectral measurements were obtained from the uppermost fully expanded leaves at the grain fill stage of growth. Fluorescence measurements were compared with the following physiological parameters: rate of photosynthesis, elemental composition, pigment and protein concentration, and grain yield. The goals of this study were to characterize leaf level fluorescence emissions as they relate physiological changes within the plant in response to nitrogen supply. Ultimately, this research is directed toward providing a remote non-destructive technique to distinguish inadequate and over fertilization of corn crops with nitrogen fertilizers. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Corp, LA (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2831-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3382 BP 80 EP 90 DI 10.1117/12.312631 PG 11 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BL36P UT WOS:000075291200008 ER PT S AU Kim, M Cecchi, G Chappelle, E Bazzani, M McMurtrey, J Corp, L Sandu, R Tirelli, D AF Kim, M Cecchi, G Chappelle, E Bazzani, M McMurtrey, J Corp, L Sandu, R Tirelli, D BE Narayanan, RM Kalshoven, JE TI Fluorescence responses and photosynthetic rates of sun-lit and shaded leaves of Italian Alpine forest species: Summer 1997 ATOM-LIFT campaign SO ADVANCES IN LASER REMOTE SENSING FOR TERRESTRIAL AND HYDROGRAPHIC APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advances in Laser Remote Sensing for Terrestrial and Hydrographic Applications CY APR 13-14, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE Alpine vegetation; Fluorescence; FLIDAR; FIS AB Terrestrial vegetation studies were carried out in the Italian Northeastern Alps in Val Visdende. The measurement site was 15 Kilometers Northeast of the town of St. Stefano di Calore (Belluno), Italy. Measurements were acquired on a wooded site at the Italian Department of Forestry Station on species native to the Italian Alps. The species included spruce (Picea abies) and alder (Alnus incana) trees. Characterization was also made of the fluorescence responses of several under-story species such as Dactylorhiza fuchsii of the Orchidaceae family, Caltha palustris and Ranunculus ficaria of the Ranuncolcee family, and Trifolium pratense and Trifolium repens of the Leguminosae family. Terrestrial vegetation monitoring was conducted with the Italian FLIDAR remote sensing instrument mounted in a mobile van, the NASA/USDA Fluorescence Imaging System (FIS), and the Spectron SE-590 for optical properties. Photosynthetic CO, gas exchange rates were made with LI-COR 6400 infrared gas analyzer. Pigments from the samples were extracted and analyzed with a Perkin Elmer Lamda 7 Spectrometer to determine pigment concentrations. Fluorescence responses were collected from vegetation samples grown under different ambient light regimes of sun-lit versus shaded. The vegetation showed different fluorescence characteristics. A fluorescence algorithm, (F740/F680)/F550, and rate of photosynthesis showed a strong Linear relationship. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Kim, M (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2831-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3382 BP 118 EP 125 DI 10.1117/12.312617 PG 8 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BL36P UT WOS:000075291200012 ER PT S AU Kim, MS Lee, EH Mulchi, CL McMurtrey, JE Chappelle, EW Rowland, RA AF Kim, MS Lee, EH Mulchi, CL McMurtrey, JE Chappelle, EW Rowland, RA BE Narayanan, RM Kalshoven, JE TI Fluorescence imaging of soybean flavonol isolines SO ADVANCES IN LASER REMOTE SENSING FOR TERRESTRIAL AND HYDROGRAPHIC APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advances in Laser Remote Sensing for Terrestrial and Hydrographic Applications CY APR 13-14, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE fluorescence imaging system; fluorescence emission; soybean; kaempferol glycosides AB Experiments were conducted to characterize the fluorescence emissions of leaves from four soybean ('Harosoy') plants containing different concentrations of flavonols (kaempferol glycosides). The investigation utilized genetically mutated soybean flavonol isolines grown in a constant environment, thus limiting factors known to affect fluorescence emission characteristics other than different kaempferol glycosides concentrations. Flavonol isolines included OX922, OX941, OX942, and OX944. The first two isolines contain kaempferol (K) glycosides; K3, K6, and K9, and the latter two did not have K3, K6, and K9. A fluorescence imaging system (FIS) was used to characterize steady state fluorescence images of the sample leaves measured at wavelengths centered at 450, 550, 680, and 740 nn with an excitation at 360 nm. Images taken with FIS greatly complement non-imaging fluorescence measurements by characterizing the spatial variation of fluorescence within leaves. We also acquired fluorescence emission spectra to characterize spectral features of the soybean flavonol isolines. The emission spectral shape of the fluorescence emission characteristics were not significantly different between the soybeans that contain kaempferol glycosides and the ones that do not contain kaempferol glycosides. Typical emission maxima of green vegetation in the blue, green, red, and far-red bands were noticed in all four soybean isolines. However, plants containing kaempferol glycosides, OX922 and OX941 had significantly lower intensities throughout the wavelength regions. These results imply that fluorescence emission intensities in the fluorescence emission bands studied are significantly affected by the presence and absence of kaempferol glycosides concentrations (UV radiation screening compounds). Pure kaempferol glycoside dissolved in solution show minimal fluorescence emission when excited with the absorption maximum radiation at 365 nn. However, a broad band emission can be seen in the green region of the spectrum when excited with radiation in the blue region of the spectrum. Thus, green fluorescence emission due to kaempferol glycosides excited by the blue fluorescent compounds with UV excitation (resonance energy excitation) could become a factor in the fluorescence studies of in vivo plants. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Kim, MS (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 2 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2831-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3382 BP 170 EP 178 DI 10.1117/12.312625 PG 9 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BL36P UT WOS:000075291200019 ER PT S AU Chien, S Stechert, A Mutz, D AF Chien, S Stechert, A Mutz, D BE Jordan, MI Kearns, MJ Solla, SA TI On efficient heuristic ranking of hypotheses SO ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 10 SE ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS LA English DT Proceedings Paper CT 11th Annual Conference on Neural Information Processing Systems (NIPS) CY DEC 01-06, 1997 CL DENVER, CO AB This paper considers the problem of learning the ranking of a set of alternatives based upon incomplete information (e.g., a limited number of observations). We describe two algorithms for hypothesis ranking and their application for probably approximately correct (PAC) and expected loss (EL) learning criteria. Empirical results are provided to demonstrate the effectiveness of these ranking procedures on both synthetic datasets and real-world data from a spacecraft design optimization problem. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chien, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 525-3660, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 USA SN 1049-5258 BN 0-262-10076-2 J9 ADV NEUR IN PY 1998 VL 10 BP 444 EP 450 PG 7 WC Behavioral Sciences; Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Neurosciences SC Behavioral Sciences; Computer Science; Neurosciences & Neurology GA BL32J UT WOS:000075130700063 ER PT S AU Hui, A Blosiu, JO Wiberg, DV AF Hui, A Blosiu, JO Wiberg, DV BE Conley, W TI Taguchi method applied in optimization of Shipley SJR5740 positive resist deposition SO ADVANCES IN RESIST TECHNOLOGY AND PROCESSING XV, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 15th Annual SPIE Conference on Advances in Resist Technology and Processing CY FEB 23-25, 1998 CL SANTA CLARA, CA SP SPIE AB Taguchi Methods of Robust Design presents a way to optimize output process performance through an organized set of experiments by using orthogonal arrays. Analysis of variance and signal-to-noise ratio is used to evaluate the contribution of each of the process controllable parameters in the realization of the process optimization. In the photoresist deposition process, there are numerous controllable parameters that can affect the surface quality and thickness of the final photoresist layer. To maximize the thickness and minimize the bubble formation of Shipley SJR 5740 photoresist tour optimum goal), eleven control parameters were selected and evaluated at two distinct levels. For a full factorial matrix experiment, 2048 experiments would have been necessary. Instead, by utilizing the orthogonal array concept, only 12 experiments were necessary for the optimization. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hui, A (reprint author), CALTECH, Jet Prop Lab, MS 302-201,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2778-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3333 BP 1304 EP 1313 DI 10.1117/12.312344 PN 1-2 PG 2 WC Chemistry, Multidisciplinary; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics; Polymer Science SC Chemistry; Engineering; Materials Science; Optics; Polymer Science GA BL41Z UT WOS:000075444000128 ER PT J AU Watson, WR Tanner, SE Parrott, TL AF Watson, WR Tanner, SE Parrott, TL TI Optimization method for educing variable-impedance liner properties SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/CEAS 3rd Aeroacoustics Conference CY MAY 12-14, 1997 CL ATLANTA, GEORGIA SP AIAA, CEAS AB A new approach to educing normal incidence acoustic impedance of nonuniform test specimens in grazing incidence and grazing-how environments is described. An optimization algorithm is shown to provide an efficient means for searching out an impedance distribution to match the measured acoustic field along the upper wall of a duct opposite the test specimen. The how duct is allowed to transmit multimodal, nonprogressive acoustic waves in a how environment; however, only a no-flow environment is discussed. A key feature of the method is the expansion of the impedance function as a piecewise continuous polynomial with undetermined coefficients. The upper wall acoustic pressure is computed numerically as a function of these coefficients by using a finite element method. The Davidon-Fletcher-Powell optimization algorithm is used to educe the normal incidence impedance by determining the values of the undetermined coefficients that minimize the difference between the measured and the numerically computed upper wall pressure, Results show that this more robust method reduces by a factor of 30 the time required to make impedance determinations as compared with the contour deformation method and is better suited for liners with spatially varying impedance. C1 NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Struct Acoust Branch, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. RP Watson, WR (reprint author), NASA, Langley Res Ctr, Aerodynam & Acoust Methods Branch, Fluid Mech & Acoust Div, Mail Stop 128, Hampton, VA 23681 USA. NR 8 TC 5 Z9 5 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 1998 VL 36 IS 1 BP 18 EP 23 DI 10.2514/2.369 PG 6 WC Engineering, Aerospace SC Engineering GA YR192 UT WOS:000071470000002 ER PT J AU Walter, MR McLoughlin, S Drinnan, AN Farmer, JD AF Walter, MR McLoughlin, S Drinnan, AN Farmer, JD TI Palaeontology of Devonian thermal spring deposits, Drummond Basin, Australia SO ALCHERINGA LA English DT Article DE Devonian; hydrothermal ecosystems; cyanobacteria; lycopsids; sphenopsids; Drummond Basin; Queensland ID HOT-SPRINGS; HYDROTHERMAL VENTS; SILICA PRECIPITATION; RHYNIE CHERT; NEW-ZEALAND; LIFE; QUEENSLAND; EVOLUTION; SCOTLAND; ORIGIN AB Molecular phylogenetic studies of extant organisms have shown that those branches of the Bacteria and Archaea that lie closest to the "last common ancestor" of all life are occupied by hyperthermophiles. At the same time, the search for former life on Mars has focussed on thermal spring deposits. For these reasons there is interest in the palaeobiology of ancient thermal spring deposits on Earth. Many such deposits are known but very few have been studied by palaeobiologists. The Devonian sinters of the Drummond Basin, Australia rank with the Rhynie cherts of Scotland as the oldest well established examples of fossil subaerial hot springs. The Drummond Basin sinters are closely comparable with modem examples in Yellowstone National Park, Wyoming, and elsewhere. It is possible to recognise a range of palaeoenvironments from high temperature vents through former hot-water channelways and terraces to ambient temperature marsh deposits. Cyanobacterial stromatolites and microfossils are abundant in those palaeoenvitronments characterised by temperatures well above ambient, and the mash and other ambient temperature palaeoenvironments contain abundant herbaceous lycopsids and sphenopsids encrusted by microbial overgrowths. C1 Macquarie Univ, Sch Earth Sci, N Ryde, NSW 2109, Australia. Univ Melbourne, Sch Bot, Parkville, Vic 3052, Australia. NASA, Ames Res Ctr, Planetary Biol Branch, Moffett Field, CA 94035 USA. RP Walter, MR (reprint author), Macquarie Univ, Sch Earth Sci, N Ryde, NSW 2109, Australia. EM Malcolm.Walter@mq.edu.au OI DRINNAN, ANDREW/0000-0003-0087-1714 NR 94 TC 46 Z9 46 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0311-5518 J9 ALCHERINGA JI Alcheringa PY 1998 VL 22 IS 3-4 BP 285 EP 314 DI 10.1080/03115519808619328 PG 30 WC Paleontology SC Paleontology GA 124YX UT WOS:000076211300007 ER PT S AU Hall, DK Foster, JL Chang, ATC Benson, CS Chien, JYL AF Hall, DK Foster, JL Chang, ATC Benson, CS Chien, JYL BE McClung, DM TI Determination of snow-covered area in different land covers in central Alaska, USA, from aircraft data - April 1995 SO ANNALS OF GLACIOLOGY, VOL 26, 1998 SE ANNALS OF GLACIOLOGY LA English DT Proceedings Paper CT International Symposium on Snow and Avalanches CY MAY 26-30, 1997 CL CHAMONIX MONT BLANC, FRANCE SP Int Glaciol Soc (IGS), Assoc Natl Etude Neige Avalanches (ANENA), Ville de Chamonix Mont-Blanc, CEMAGREF, Div Nivologie, Meteo-France, Ctr Etudes Neige, Reg Rhone-Alps, Minist Amenagement Territoire Environm, Minist Affaires Etrangeres, Lab Glaciol Geophys Environm, CNRS, STMB Chemin Montenvers AB During April 1995, a field and aircraft experiment was conducted in central Alaska in support of the moderate Resolution Imaging Spectroradiometer (MODIS) snow-mapping project. The MODIS Airborne Simulator (MAS), a 50 channel spectroradiometer, was flown on board the NASA ER-2 aircraft. An objective of the mission was to determine the accuracy of mapping snow in different surface covers using an algorithm designed to map global snow cover after the launch of MODIS in 1998. The surface cover in this area of central Alaska is typically spruce, birch, aspen, mixed forest and muskeg. Integrated reflectance, R-i, was calculated from the visible/near-infrared channels of the MAS sensor The R-i was used to estimate different vegetation-cover densities because there is an inverse relationship between vegetation-cover density and albedo in snow-covered terrain. A vegetation-cover density map was constructed using MAS data acquired on 13 April 1995 over central Alaska. In the part of the scene that was mapped as having a vegetation-cover density of < 50%, the snow-mapping algorithm mapped 96.41% snow cover. These areas are generally composed of muskeg and mixed forests and include frozen lakes. In the part of the scene that was estimated to have a vegetation-cover density of greater than or equal to 50%, the snow-mapping algorithm mapped 71.23% snow cover. These areas are generally composed of dense coniferous or deciduous forests. Overall, the accuracy of the snow-mapping algorithm is > 87.41% for a 13 April MAS scene with a variety of surface covers (coniferous and deciduous and mixed forests, muskeg, tundra and frozen lakes). C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. 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 0 TC 8 Z9 8 U1 0 U2 0 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-21-0 J9 ANN GLACIOL PY 1998 VL 26 BP 149 EP 155 PG 7 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA BL73A UT WOS:000076481500029 ER PT S AU Rignot, E AF Rignot, E BE Budd, WF TI Radar interferometry detection of hinge-line migration on Rutford Ice Stream and Carlson Inlet, Antarctica SO ANNALS OF GLACIOLOGY, VOL 27, 1998 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Antarctica and Global Change - Interactions and Impacts CY JUL 13-18, 1997 CL HOBART, AUSTRALIA SP Cooperative Res Ctr Antarctica, SO Ocean (Antarctic CRC), Australian Antarctic Div, Int Glaciol Soc, Global Change & Antarctic program of SCAR ID GROUNDING LINES; SHEET; GREENLAND; MOTION; SHELF AB Satellite synthetic aperture radar interferometry is employed to map the hinge-line position, or limit of tidal flexing, of Rutford Ice Stream (RIS) and Carlson Inlet (CI), Antarctica, and detect its horizontal migration between 1992 and 1996. The hinge-line position is mapped using a model fit from an elastic-beam theory. The rms noise of the model fit is 1-7 mm. The hinge-line position is located with a statistical noise of 30-50 m. Using this method, we find no hinge-line migration on RIS and CI. Only the southern flank of CI, which is stagnant (velocity 10-20 m a(-1) vs 100 m a(-1) in the main flow of CI), retreated 376 +/- 36 m in 1 years. The effect of changes in ocean tide is calculated to yield a 60 m advance of the hinge-line position in our data. Hence, the detected stationarity of the hinge-line positions suggests stable ice-thickness conditions at the hinge line, except for the southern flank of CI which may be thinning. A comparison of the ice discharge calculated at the grounding line of RIS (17 +/- 2 km(3) ice a(-1)) and of CI Ice a (2.9 +/- 0.3km(3) a(-1) ) with mass input from the interior regions (20 +/- 3 km(3) ice a(-1) for RIS and 2.9 +/- 0.4 km(3) a(-1) for CI) suggests a balanced mass budget for CI, whereas RIS may have a slightly positive mass budget of 3 +/- 4 km(3) ice a(-1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rignot, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 300-235, Pasadena, CA 91109 USA. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 27 TC 23 Z9 23 U1 0 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-22-9 J9 ANN GLACIOL PY 1998 VL 27 BP 25 EP 32 PG 8 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Geology; Meteorology & Atmospheric Sciences GA BM76J UT WOS:000079713100004 ER PT S AU Gudmundsson, GH Raymond, CF Bindschadler, R AF Gudmundsson, GH Raymond, CF Bindschadler, R BE Budd, WF TI The origin and longevity of flow stripes on Antarctic ice streams SO ANNALS OF GLACIOLOGY, VOL 27, 1998 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Antarctica and Global Change - Interactions and Impacts CY JUL 13-18, 1997 CL HOBART, AUSTRALIA SP Cooperative Res Ctr Antarctica, SO Ocean (Antarctic CRC), Australian Antarctic Div, Int Glaciol Soc, Global Change & Antarctic program of SCAR ID WEST ANTARCTICA; SURFACE; IMAGERY AB Flow stripes along the surface of rapidly moving ice streams are shown to be an expected reaction of a viscous medium flowing over an irregular bed, whenever the velocity at the bed is large compared to shearing through the thickness. The principal features of the process are as follows. At high basal speeds the ice acts as a strongly selective band-pass filter transmitting basal undulations on spatial scales of a few ice thicknesses very effectively to the surface. The decay of the short-scale features by diffusion is strongly retarded by horizontal stress gradients. Consequently, localized disturbances at the bed produce topographic effects on the surface that are advected long distances downstream before decaying away. This mechanism may explain many of the flow stripes on active ice streams moving by rapid basal motion. C1 ETH Zentrum, Versuchanstalt Wasserbau Hydrol & Glaziol, CH-8092 Zurich, Switzerland. Univ Washington, Geophys Program, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gudmundsson, GH (reprint author), ETH Zentrum, Versuchanstalt Wasserbau Hydrol & Glaziol, Gloriastr 37-39, CH-8092 Zurich, Switzerland. RI Gudmundsson, Gudmundur Hilmar/F-6499-2012 OI Gudmundsson, Gudmundur Hilmar/0000-0003-4236-5369 NR 22 TC 47 Z9 47 U1 0 U2 4 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-22-9 J9 ANN GLACIOL PY 1998 VL 27 BP 145 EP 152 PG 8 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Geology; Meteorology & Atmospheric Sciences GA BM76J UT WOS:000079713100024 ER PT S AU Hulbe, CL Rignot, E MacAyeal, DR AF Hulbe, CL Rignot, E MacAyeal, DR BE Budd, WF TI Comparison of ice-shelf creep flow simulations with ice-front motion of Filchner-Ronne Ice Shelf, Antarctica, detected by SAR interferometry SO ANNALS OF GLACIOLOGY, VOL 27, 1998 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Antarctica and Global Change - Interactions and Impacts CY JUL 13-18, 1997 CL HOBART, AUSTRALIA SP Cooperative Res Ctr Antarctica, SO Ocean (Antarctic CRC), Australian Antarctic Div, Int Glaciol Soc, Global Change & Antarctic program of SCAR AB Comparison between numerical model ice-shelf flow simulations and synthetic aperture radar (SAR) interferograms is used to study ice-flow dynamics at the Hemmen Ice Rise (HIR) and Lassiter Coast (LC) corners of the iceberg-calving front of the Filchner-Ronne Ice Shelf. Antarctica. The interferograms are constructed from SAR images provided by the European Space Agency's remote-sensing satellites (ERS-1/2). Narrow bands of large shear strain rate are observed along the boundaries between fast-flowing ice-shelf ice and no-flow boundaries. Large rifts, opened where the ice shelf separates from the coast, appear to be filled with a melange of sea ice, ice-shelf fragments, and snell: Trial and error is used to find the best match between artificial interferograms, constructed from modelled ice flow and the observed interferograms. We find that at both HIR and LC, ice within the coastal boundary layers must be significantly softer than adjacent ice. At HIR the rift-filling ice melange transmits stress from one ice-shelf fragment to another; thus it must have mechanical competence and must moderate both separation of the ice shelf from the coast and the release of icebergs. However, the ice melange along the LC does not. The difference may be related to melange thickness, which could vary in the two locations due to differences in sub-ice-shelf oceanography or perhaps to regional atmospheric warming, currently under way along the Antarctic Peninsula. Future warming could weaken the melange ice around HIR as well, causing the ice shelf to lose contact with that shelf-front anchor. C1 Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hulbe, CL (reprint author), Univ Chicago, Dept Geophys Sci, 5734 S Ellis Ave, Chicago, IL 60637 USA. RI Rignot, Eric/A-4560-2014; OI Rignot, Eric/0000-0002-3366-0481; MacAyeal, Douglas/0000-0003-0647-6176 NR 10 TC 7 Z9 7 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-22-9 J9 ANN GLACIOL PY 1998 VL 27 BP 182 EP 186 PG 5 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Geology; Meteorology & Atmospheric Sciences GA BM76J UT WOS:000079713100029 ER PT S AU Zwally, HJ Giovinetto, M Craven, M Morgan, V Goodwin, I AF Zwally, HJ Giovinetto, M Craven, M Morgan, V Goodwin, I BE Budd, WF TI Areal distribution of the oxygen-isotope ratio in Antarctica: comparison of results based on field and remotely sensed data SO ANNALS OF GLACIOLOGY, VOL 27, 1998 SE Annals of Glaciology-Series LA English DT Article; Proceedings Paper CT International Symposium on Antarctica and Global Change - Interactions and Impacts CY JUL 13-18, 1997 CL HOBART, AUSTRALIA SP Cooperative Res Ctr Antarctica, SO Ocean (Antarctic CRC), Australian Antarctic Div, Int Glaciol Soc, Global Change & Antarctic program of SCAR ID ICE SHEETS; TEMPERATURE; ACCUMULATION; OCEAN; LAND AB An updated compilation of oxygen-isotope ratio data for 562 sites in Antarctica shows a significant increase in the number of sites and an improvement in the representation of the coastal zone over previous versions. The data base consists of ratio values (delta(18)O; multi-year mean (18)O/(16)O relative to Standard Mean Ocean Water, in parts per thousand) compiled as the dependent variable, together with data for the so-called independent variables: latitude, surface elevation, mean annual surface temperature and mean annual shortest distance to open ocean denoted by the 20% sea-ice concentration boundary. The problem of covariation between so-called independent variables is minimized using stepwise regression analyses. A general model is described using all the field data, and the regional variation at drainage-system scale is assessed by contrasting models for two physiographically distinct regions. In addition, entity-specific models are determined using data subsets for the conterminous grounded-ice and ice-shelf areas. Inversions of the specific models are applied to a 100 km grid data base to produce two contoured distributions of the ratio, one based on field data, and the other on remotely sensed data. The difference between these produces residuals that, relative to the summation of standard errors of the models, are small in most of the interior area of the ice sheet, and large in several areas of mountain and coastal regions, where interpolation and extrapolation of field data are particularly unreliable. Remotely sensed data generally produce ratio values which are isotopically cooler. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calgary, Calgary, AB T2N 1N4, Canada. Antarctic CRC, Hobart, Tas 7001, Australia. Australian Antarctic Div, Hobart, Tas 7001, Australia. SCAR, GLOCHANT Project Off, Hobart, Tas 7001, Australia. RP Zwally, HJ (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 33 TC 13 Z9 14 U1 0 U2 0 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-22-9 J9 ANN GLACIOL-SER PY 1998 VL 27 BP 583 EP 590 PG 8 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Geology; Meteorology & Atmospheric Sciences GA BM76J UT WOS:000079713100096 ER PT S AU Neumann, K Lyons, WB Des Marais, DJ AF Neumann, K Lyons, WB Des Marais, DJ BE Budd, WF TI Inorganic carbon-isotope distribution and budget in the Lake Hoare and Lake Fryxell basins, Taylor valley, Antarctica SO ANNALS OF GLACIOLOGY, VOL 27, 1998 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Antarctica and Global Change - Interactions and Impacts CY JUL 13-18, 1997 CL HOBART, AUSTRALIA SP Cooperative Res Ctr Antarctica, SO Ocean (Antarctic CRC), Australian Antarctic Div, Int Glaciol Soc, Global Change & Antarctic program of SCAR ID ICE; BIOGEOCHEMISTRY; PHYTOPLANKTON; MATS AB One of the unusual features of lakes Fryxell and Hoare in Taylor Valley southern Victoria Land, Antarctica, is their perennial ice cover. This ice cover limits gas exchange between the atmosphere and the lake water, and causes a very stable stratification of the lakes. We analyzed a series of water samples from profiles of these lakes and their tributaries for delta(13)C of the dissolved inorganic carbon (DIC) in order to qualify the carbon flux from the streams into the lakes, and to investigate the carbon cycling within the lakes. Isotopic values in the uppermost waters (delta(13)C = +1.3 parts per thousand to 5.3 parts per thousand in Lake Hoare, +0.4 parts per thousand to +3.0 parts per thousand in Lake Fryxell) are close to the carbon-isotope values encountered in the streams feeding Lake Fryxell, but distinctively heavier than in streams feeding Lake Hoare (delta(13)C = -2.3 parts per thousand to 1.4 parts per thousand). These ratios are much heavier than ratios found in the moat that forms around the lakes in January-February (delta(13)C = -10.1 parts per thousand). In the oxic photic zones of the lakes, photosynthesis clearly influences the isotopic composition, with layers of high productivity having enriched carbon-isotope signatures (delta(13)C = +2.7 parts per thousand to +6.1 parts per thousand). In both lakes, the isotopic values become lighter with depth, reaching minima of -3.2 parts per thousand and -4.0 parts per thousand in Lakes Fryxell and Hoare, respectively These minima are caused by the microbial remineralization of isotopically light organic carbon. Mie present DIC flux calculations that help to interpret the isotopic distribution. For example, in Lake Hoare the higher utilization of CO2aq, and a substantially smaller inflow of CO2 from streams cause the heavier observed isotopic ratios. Differences in the hydrology and stream morphologies of the tributaries also greatly influence the carbon budgets of the basins. C1 Univ Alabama, Dept Geol, Tuscaloosa, AL 35487 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Neumann, K (reprint author), Univ Alabama, Dept Geol, Tuscaloosa, AL 35487 USA. NR 34 TC 9 Z9 9 U1 1 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-22-9 J9 ANN GLACIOL PY 1998 VL 27 BP 685 EP 690 PG 6 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Geology; Meteorology & Atmospheric Sciences GA BM76J UT WOS:000079713100113 ER PT J AU Cybulski, JL Neal, RDB Kram, A Allen, JC AF Cybulski, JL Neal, RDB Kram, A Allen, JC TI Reuse of early life-cycle artifacts: workproducts, methods and tools SO ANNALS OF SOFTWARE ENGINEERING LA English DT Review ID SOFTWARE AB In this article we describe the importance of reusing software artifacts resulting from the earliest stages of the development life-cycle, i.e., software conception, requirements analysis, feasibility study, requirements specification, architectural and detailed design. Although reuse of early artifacts is deemed beneficial to software development projects, there are no readily available software tools that could facilitate their effective reuse. Hence, we identified nearly one hundred early artifact types. We analyzed, compared and contrasted them. We clustered similar artifact types into distinct artifact affinity groups. We then proposed several methods and techniques useful in the processing of these artifacts to support their reuse. We believe that the proposed methods could be utilized by tool builders to construct software development environments capable of assisting analysts, designers, architects and programmers to effectively reuse the results of early life-cycle activities. C1 Univ Melbourne, Dept Informat Syst, Parkville, Vic 3052, Australia. WVU, NASA, Software Res Lab, Fairmont, WV 26554 USA. Motorola Inc, Arlington Hts, IL 60004 USA. Univ Maine, Dept Comp Sci, Orono, ME 04473 USA. RP Cybulski, JL (reprint author), Univ Melbourne, Dept Informat Syst, Parkville, Vic 3052, Australia. EM j.cybulski@dis.unimelb.edu.au NR 19 TC 4 Z9 4 U1 0 U2 0 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1022-7091 J9 ANN SOFTW ENG JI Ann. Softw. Eng. PY 1998 VL 5 BP 227 EP 251 DI 10.1023/A:1018983220136 PG 25 WC Computer Science, Software Engineering SC Computer Science GA 129BG UT WOS:000076442900009 ER PT J AU Addy, EA AF Addy, EA TI A framework for performing verification and validation in reuse-based software engineering SO ANNALS OF SOFTWARE ENGINEERING LA English DT Review AB Verification and Validation (V&V) is currently performed during application development for many systems, especially safety-critical and mission-critical systems. The V&V process is intended to discover errors, especially errors related to critical processing, as early as possible during the development process. The system application provides the context under which the software artifacts are validated. This paper describes a framework that extends V&V from an individual application system to a product line of systems that are developed within an architecture-based software engineering environment. This framework includes the activities of traditional application-level V&V, and extends these activities into domain engineering and into the transition between domain engineering and application engineering. The framework includes descriptions of the types of activities to be performed during each of the life-cycle phases, and provides motivation for the activities. C1 WVU, NASA, Software Res Lab, Software IV&V Facil, Fairmont, WV 26554 USA. RP WVU, NASA, Software Res Lab, Software IV&V Facil, 100 Univ Dr, Fairmont, WV 26554 USA. EM eaddy@wvu.edu NR 20 TC 5 Z9 5 U1 1 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1022-7091 J9 ANN SOFTW ENG JI Ann. Softw. Eng. PY 1998 VL 5 BP 279 EP 292 DI 10.1023/A:1018968222862 PG 14 WC Computer Science, Software Engineering SC Computer Science GA 129BG UT WOS:000076442900011 ER PT J AU Joslin, RD AF Joslin, RD TI Aircraft laminar flow control SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE boundary-layer control; LFC design tools; insect contamination; suction LFC; manufacturing tolerance ID BOUNDARY-LAYER-TRANSITION; SWEPT WINGS; MECHANISMS; STABILITY; VORTICES AB Aircraft laminar flow control (LFC) from the 1930s through the 1990s is reviewed and the current status of the technology is assessed. Examples are provided to demonstrate the benefits of LFC for subsonic and supersonic aircraft. Early studies related to the laminar boundary-layer flow physics, manufacturing tolerances for laminar flow, and insect-contamination avoidance are discussed. LFC concept studies in wind-tunnel and flight experiments are the major focus of the paper. LFC design tools are briefly outlined for completeness. C1 NASA, Langley Res Ctr, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. RP Joslin, RD (reprint author), NASA, Langley Res Ctr, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. NR 112 TC 112 Z9 121 U1 1 U2 17 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1998 VL 30 BP 1 EP 29 DI 10.1146/annurev.fluid.30.1.1 PG 29 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YV950 UT WOS:000071880700002 ER PT J AU Canuto, VM Christensen-Dalsgaard, J AF Canuto, VM Christensen-Dalsgaard, J TI Turbulence in astrophysics: Stars SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE turbulence; helioseismology; buoyancy; internal rotation ID SOLAR CONVECTION ZONE; REYNOLDS STRESS APPROACH; MIXING-LENGTH THEORY; COMPRESSIBLE CONVECTION; DYNAMICAL MODEL; PULSATIONAL STABILITY; ACOUSTIC-OSCILLATIONS; STELLAR CONVECTION; P-MODES; F-MODE AB Turbulence is ubiquitous in astrophysics, ranging from cosmology, interstellar medium to stars, supernovae, accretion disks, etc. Large scales and small viscosities combine to form large Reynolds numbers. Because it is not possible in a single article to review all the above scenarios, we limit ourselves to stars, in which thermal instabilities give rise to turbulent convection as the dominant heat transport mechanism. (Accretion disks, where shear instabilities dominate the outward transport of angular momentum, will be the subject of a second article, planned for Volume 31.) Because of the lack of a satisfactory theory, turbulence constitutes a bottleneck that prevents astrophysical models from being fully predictive. Because continued use of phenomenological turbulence expressions would make astrophysical models perennially unpredictive, a way must be found to make astrophysical models as prognostic as possible. In addition to the difficulties brought about by turbulence, astrophysical settings introduce "malicious conditions," of which the most refractory to a satisfactory quantification are compressibility (caused by the large density excursions that characterize convective zones in stars) and rotation. Basic understanding of how they affect turbulence in general is still rather sketchy. Reasons for the choice of stars and accretion disks as prototype examples are the following: The underlying instabilities are very basic; laboratory and direct numerical simulations data help constrain theoretical models; and new observational data, especially from helioseismology, help discriminate among different models with unprecedented accuracy. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys, New York, NY 10025 USA. Danish Natl Res Fdn, Theoret Astrophys Ctr, DK-8000 Aarhus, Denmark. Univ Aarhus, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM acvmc@masagiss.giss.nasa.gov; jcd@obs.aau.dk NR 121 TC 30 Z9 30 U1 0 U2 2 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1998 VL 30 BP 167 EP 198 DI 10.1146/annurev.fluid.30.1.167 PG 32 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YV950 UT WOS:000071880700008 ER PT J AU Moin, P Mahesh, K AF Moin, P Mahesh, K TI Direct numerical simulation: A tool in turbulence research SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE computational fluid dynamics; numerical resolution; hot-wire anemometry; vorticity; shock waves; turbulence modeling; boundary layer structure ID HOMOGENEOUS ISOTROPIC TURBULENCE; LOW-REYNOLDS-NUMBER; FINITE-DIFFERENCE SCHEMES; NAVIER-STOKES EQUATIONS; SHOCK-CAPTURING SCHEMES; LARGE-EDDY SIMULATIONS; NEAR-WALL TURBULENCE; BOUNDARY-LAYER; CHANNEL FLOW; PASSIVE SCALAR AB We review the direct numerical simulation (DNS) of turbulent hows. We stress that DNS is a research tool, and not a brute-force solution to the Navier-Stokes equations for engineering problems. The wide range of scales in turbulent flows requires that care be taken in their numerical solution. We discuss related numerical issues such as boundary conditions and spatial and temporal discretization. Significant insight into turbulence physics has been gained from DNS of certain idealized flows that cannot be easily attained in the laboratory. We discuss some examples. Further, we illustrate the complementary nature of experiments and computations in turbulence research. Examples are provided where DNS data has been used to evaluate measurement accuracy. Finally, we consider how DNS has impacted turbulence modeling and provided further insight into the structure of turbulent boundary layers. C1 Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. EM moin@ctr-next12.stanford.edu; krishnan@leland.stanford.edu NR 173 TC 577 Z9 608 U1 16 U2 139 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1998 VL 30 BP 539 EP 578 DI 10.1146/annurev.fluid.30.1.539 PG 40 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YV950 UT WOS:000071880700019 ER PT J AU Meador, MA AF Meador, MA TI Recent advances in the development of processable high-temperature polymers SO ANNUAL REVIEW OF MATERIALS SCIENCE LA English DT Review DE polymers; polyimides; composites ID AROMATIC POLYIMIDE FIBERS; BISPHENOL-A POLYCARBONATES; END-CAPPED POLYQUINOLINE; LOW DIELECTRIC-CONSTANTS; DIELS-ALDER POLYMER; SOLUBLE POLYIMIDES; THERMAL-PROPERTIES; CROSS-LINKING; POLY(ARYL PREHNITIMIDE)S; POLY(ETHER IMIDE)S AB High-temperature polymers have found widespread use in aerospace and electronics applications. This review deals with recent developments in the chemistry of these materials that have led to improvements in processability and high-temperature stability. C1 NASA, Lewis Res Ctr, Polymers Branch, Cleveland, OH 44135 USA. RP Meador, MA (reprint author), NASA, Lewis Res Ctr, Polymers Branch, Cleveland, OH 44135 USA. EM Michael.A.Meador@lerc.nasa.gov NR 116 TC 112 Z9 130 U1 8 U2 54 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0084-6600 J9 ANNU REV MATER SCI JI Annu. Rev. Mater. Sci. PY 1998 VL 28 BP 599 EP 630 DI 10.1146/annurev.matsci.28.1.599 PG 32 WC Materials Science, Multidisciplinary SC Materials Science GA 110TC UT WOS:000075395600023 ER PT S AU Kiang, RK AF Kiang, RK BE Rogers, SK Fogel, DB Bezdek, JC Bosacchi, B TI Characterization of global vegetation using AVHRR data SO APPLICATIONS AND SCIENCE OF COMPUTATIONAL INTELLIGENCE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE International Conference on Applications and Science of Computational Intelligence CY APR 13-16, 1998 CL ORLANDO, FL SP SPIE, Int Soc Opt Engn DE remote sensing; multispectral classification; multitemporal; vegetation index; global warming AB Increase in the levels of carbon dioxide and other greenhouse gases over the next half-century may result in an increase in global mean temperature. The recent discoveries of possible advance of arctic tree line into the tundra and earlier greening of northern vegetation provide additional warnings that global warming may indeed be occurring. On the Earth surface, land cover and its changes affect the coupling between the biosphere and the atmosphere, and control many important Earth system processes. Satellite remote sensing provides long-term, repeated coverage over extended area and is the essential data source for monitoring climate changes. An Advanced Very-High Resolution Radiometer (AVHRR) Pathfinder dataset from 1987, in 1 degrees latitude-longitude resolution is used in this study. Two reflective channels, two thermal channels, and Normalized Difference Vegetation Index are the input parameters. In conjunction with a global vegetation ground truth, a multi-layer neural network is trained and used for global vegetation characterization. As the same type of vegetation may appear very differently over different parts of the Earth at any given time, global classification is more difficult than local classification. It is shown that a multitemporal approach, in which data from multiple dates are used, may improve the accuracy. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kiang, RK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 3 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2839-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3390 BP 113 EP 120 DI 10.1117/12.304796 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Optics SC Computer Science; Optics GA BK80N UT WOS:000073452600012 ER PT S AU Duong, TA Saunders, C Ngo, T Daud, T AF Duong, TA Saunders, C Ngo, T Daud, T BE Rogers, SK Fogel, DB Bezdek, JC Bosacchi, B TI Winner/loser-take-all circuits on SOI technology for neural network classification SO APPLICATIONS AND SCIENCE OF COMPUTATIONAL INTELLIGENCE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE International Conference on Applications and Science of Computational Intelligence CY APR 13-16, 1998 CL ORLANDO, FL SP SPIE, Int Soc Opt Engn AB High connectivity of artificial neural network chip-embodiments combined with currently emerging 3-dimensionally stacked multichip modules for rear-time applications of target classification require a scrutiny for low power technology insertion. Conventional CMOS high power consumption limits the allowable density of synapse/neuron elements. However Silicon-On-Insulator (SOI) technology has the potential for successful implementation of-high density neural network because of the following unique features: (a) Operating voltage is reduced 3-fold from 5 to 1.5 volts, reducing power requirements by 9-fold; (b) Reduced substrate offers reduced capacitance and power and an increased speed; and, (c) Latch-up phenomenon is eliminated. Here we describe two practical winner/loser-take-all (W/LTA) circuits fabricated with 0.25 mu m fully depleted SOI technology that are useful for neural networks and as compared to other such circuits offer considerable advantage of speed and performance. SPICE circuit simulations show that up to 9-bit resolution can be obtained between a winner and a loser input and with two cascaded circuits. Final characterization tests prove that constructing circuit elements from SOI technology would allow us to build large size neural networks for practical applications. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Duong, TA (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2839-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3390 BP 367 EP 377 DI 10.1117/12.304827 PG 11 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Optics SC Computer Science; Optics GA BK80N UT WOS:000073452600039 ER PT S AU Fang, WC AF Fang, WC BE Rogers, SK Fogel, DB Bezdek, JC Bosacchi, B TI A low-power smart vision system-on-a-chip design for ultra-fast machine vision applications SO APPLICATIONS AND SCIENCE OF COMPUTATIONAL INTELLIGENCE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE International Conference on Applications and Science of Computational Intelligence CY APR 13-16, 1998 CL ORLANDO, FL SP SPIE, Int Soc Opt Engn DE vision system; active pixel sensor; neural processor; system-on-a-chip; smart sensor AB In this paper, an ultra-fast smart vision system-on-a-chip design is proposed to provide effective solutions for real time machine vision applications by taking advantages of recent advances in integrated sensing/processing designs, electronic neural networks, advanced microprocessors and sub-micron VLSI technology. The smart vision system mimics what is inherent in biological vision systems. It is programmable to perform vision processing in all levels such as image acquisition, image fusion, image analysis, and scene interpretation. A system-on-a-chip implementation of this smart vision system is shown to be feasible by integrating the whole system into a 3-cm x 3-cm chip design in a 0.18-mu m CMOS technology. The system achieves one tera-operation-per-second computing power that is a two order-of-magnitude increase over the state-of-the-art microcomputer and DSP chips. Its high performance is due to massively parallel computing structures, high data throughput rates, fast learning capabilities, and advanced VLSI system-on-a-chip implementation. This highly integrated smart vision system can be used for various NASA scientific missions and other military, industrial or commercial vision applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fang, WC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 198-219, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2839-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3390 BP 666 EP 675 DI 10.1117/12.304795 PG 10 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Optics SC Computer Science; Optics GA BK80N UT WOS:000073452600068 ER PT J AU Biswas, R Strawn, RC AF Biswas, R Strawn, RC TI Tetrahedral and hexahedral mesh adaptation for CFD problems SO APPLIED NUMERICAL MATHEMATICS LA English DT Article; Proceedings Paper CT International-Centre-for-Mathematical-Sciences Meeting on Grid Adaptation in Computational PDEs CY JUL 01-05, 1996 CL EDINBURGH, SCOTLAND SP Int Ctr Math Sci ID UNSTRUCTURED MESHES; GRIDS; GENERATION; REFINEMENT AB This paper presents two unstructured mesh adaptation schemes for problems in computational fluid dynamics. The procedures allow localized grid refinement and coarsening to efficiently capture aerodynamic flow features of interest. The first procedure is for purely tetrahedral grids; unfortunately, repeated anisotropic adaptation may significantly deteriorate the quality of the mesh. Hexahedral elements, on the other hand, can be subdivided anisotropically without mesh quality problems. Furthermore, hexahedral meshes yield more accurate solutions than their tetrahedral counterparts for the same number of edges, Both the tetrahedral and hexahedral mesh adaptation procedures use edge-based data structures that facilitate efficient subdivision by allowing individual edges to be marked for refinement or coarsening. However, for hexahedral adaptation, pyramids, prisms, and tetrahedra are used as buffer elements between refined and unrefined regions to eliminate hanging vertices. Computational results indicate that the hexahedral adaptation procedure is a viable alter-native to adaptive tetrahedral schemes. (C) 1998 Elsevier Science B.V. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, USA, AFDD, Moffett Field, CA 94035 USA. RP Biswas, R (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, MS T27A-1, Moffett Field, CA 94035 USA. NR 20 TC 29 Z9 30 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JAN PY 1998 VL 26 IS 1-2 BP 135 EP 151 DI 10.1016/S0168-9274(97)00092-5 PG 17 WC Mathematics, Applied SC Mathematics GA YT547 UT WOS:000071618000012 ER PT S AU Mehrotra, P Van Rosendale, J Zima, H AF Mehrotra, P Van Rosendale, J Zima, H BE Kagstrom, B Dongarra, J Elmroth, E Wasniewski, J TI High Performance Fortran: Status and prospects SO APPLIED PARALLEL COMPUTING: LARGE SCALE SCIENTIFIC AND INDUSTRIAL PROBLEMS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 4th International Workshop on Applied Parallel Computing (PARA 98) CY JUN 14-17, 1998 CL UMEA UNIV, UMEA, SWEDEN SP Umea Univ, Swedish Council High Perform Comp, Swedish Nat Sci Res Council, Swedish Res Council Engn Sci, IBM Sweden HO UMEA UNIV ID SIMULATION; EXECUTION; LOOPS AB High Performance Fortran (HPF) is a data-parallel language that was designed to provide the user with a high-level interface for programming scientific applications, while delegating to the compiler the task of generating an explicitly parallel message-passing program. In this paper, we give an outline of developments that led to HPF, shortly explain its major features, and illustrate its use for irregular applications. The final part of the paper points out some classes of problems that are difficult to deal with efficiently within the HPF paradigm. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Vienna, Inst Software Technol & Parallel Syst, A-1090 Vienna, Austria. RP Mehrotra, P (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C, Hampton, VA 23681 USA. EM pm@icase.edu; jvr@icase.edu; zima@par.univie.ac.at NR 35 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65414-3 J9 LECT NOTES COMPUT SC PY 1998 VL 1541 BP 345 EP 356 PG 12 WC Computer Science, Theory & Methods SC Computer Science GA BN74B UT WOS:000082776000046 ER PT S AU Sawyer, W Lucchesi, R Lyster, P Takacs, L Larson, J Molod, A Nebuda, S Pabon-Ortiz, C AF Sawyer, W Lucchesi, R Lyster, P Takacs, L Larson, J Molod, A Nebuda, S Pabon-Ortiz, C BE Kagstrom, B Dongarra, J Elmroth, E Wasniewski, J TI Parallelization of the DAO Atmospheric General Circulation Model SO APPLIED PARALLEL COMPUTING: LARGE SCALE SCIENTIFIC AND INDUSTRIAL PROBLEMS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 4th International Workshop on Applied Parallel Computing (PARA 98) CY JUN 14-17, 1998 CL UMEA UNIV, UMEA, SWEDEN SP Umea Univ, Swedish Council High Perform Comp, Swedish Nat Sci Res Council, Swedish Res Council Engn Sci, IBM Sweden HO UMEA UNIV AB In this paper we present a parallel Atmospheric General Circulation Model currently under development at the NASA Data Assimilation Office. The constituent simulation parameterizations of the AGCM are briefly described, and the parallelization strategy discussed. The key performance obstacles to attaining target benchmarks are treated, as well as our plans for code optimization. We also present the most current benchmarks arising from the this High Performance Computing and Communications Initiative Grand Challenge project. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. RP Sawyer, W (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65414-3 J9 LECT NOTES COMPUT SC PY 1998 VL 1541 BP 510 EP 514 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BN74B UT WOS:000082776000065 ER PT S AU Wang, P Li, P AF Wang, P Li, P BE Kagstrom, B Dongarra, J Elmroth, E Wasniewski, J TI Parallel computation and visualization of 3D, time-dependent, thermal convective flows SO APPLIED PARALLEL COMPUTING: LARGE SCALE SCIENTIFIC AND INDUSTRIAL PROBLEMS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 4th International Workshop on Applied Parallel Computing (PARA 98) CY JUN 14-17, 1998 CL UMEA UNIV, UMEA, SWEDEN SP Umea Univ, Swedish Council High Perform Comp, Swedish Nat Sci Res Council, Swedish Res Council Engn Sci, IBM Sweden HO UMEA UNIV ID 3-DIMENSIONAL NATURAL-CONVECTION; SHALLOW CAVITY AB A high-resolution numerical study on parallel systems is reported on three-dimensional (3D), time-dependent, thermal convective flows. Numerical results are obtained for Rayleigh numbers up to 5 x 10(7) and for a Prandtl number 0.733 equivalent to that of air, in a cubical enclosure, which is heated differentially at two vertical sidewalls. A parallel implementation of the finite volume method with a multigrid scheme is discussed, and a parallel and distributed visualization system is developed for visualizing the flow. The details of the 3D, time-dependent flow are described. Separations of the flow near the horizontal walls occur, and y-variations of the flow are strong. Periodical flow patterns appear. The 3D solutions for such high Rayleigh number 5 x 10(7) become strong convective, time-dependent, and periodical. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, MS 168-522,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM wangp@rockymt.jpl.nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65414-3 J9 LECT NOTES COMPUT SC PY 1998 VL 1541 BP 565 EP 573 PG 9 WC Computer Science, Theory & Methods SC Computer Science GA BN74B UT WOS:000082776000073 ER PT J AU Aradhye, H Heger, AS AF Aradhye, H Heger, AS TI Recognizing patterns in information retrieval: a memory-based classifier for inferring relevancy SO ARTIFICIAL INTELLIGENCE IN ENGINEERING LA English DT Article DE information retrieval; intelligent agents; pattern recognition; memory-based reasoning ID AGENTS AB An application of memory-based reasoning (MBR) for determining the relevancy of retrieved information, customized for the needs and preferences of an individual user, is presented. The use of MBR method in conjunction with a classification scheme such as k-nearest neighbors (k-NN) can set the foundation for an intelligent agent for search of patterns in databases. An intelligent agent is an adaptive database search system that can help reduce user information overload problem. To this end, a system called VINAYAK,(dagger) has been developed to investigate various issues concerned with information retrieval as an automated function. Current experiments have focused on chemical engineering literature search and safety-related retrieval through nuclear databases. The results point towards the advantage of the use of intelligent agent methodology in conjunction with a database search engine. (C) 1997 Elsevier Science Limited. C1 Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. RP Aradhye, H (reprint author), Univ New Mexico, NASA, Ctr Autonomous Control Engn, Albuquerque, NM 87131 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0954-1810 J9 ARTIF INTELL ENG JI Artif. Intell. Eng. PD JAN-APR PY 1998 VL 12 IS 1-2 BP 99 EP 105 DI 10.1016/S0954-1810(97)00008-3 PG 7 WC Computer Science, Artificial Intelligence; Engineering, Multidisciplinary SC Computer Science; Engineering GA YM486 UT WOS:000071068300008 ER PT S AU Joosten, BK Schaefer, RJ Hoffman, SJ AF Joosten, BK Schaefer, RJ Hoffman, SJ BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Recent evolution of the Mars reference mission SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB During 1992-1994 work was done by personnel representing several NASA field centers to formulate a "Reference Mission" addressing human exploration of Mars, This Reference Mission describes an approach for the first human missions to Mars, utilizing approaches that are technically feasible, have reasonable risks, and have relatively low costs. The Reference Mission appears to have achieved better technical feasibility, risk, and cost than previous approaches. But even with these advancements, improvement was still needed in all of these areas to make the first piloted Mars mission a feasible undertaking for the spacefaring nations of Earth. NASA has recently completed a re-examination, a "scrub", of the Reference Mission in light of technology advances since the time of the original study and to refine vehicle and system concepts to help reduce mass and associated costs, This paper briefly recaps the Reference Mission as originally developed to set the stage for work recently completed. Comparisons in the form of tabular and graphical data illustrates where changes were made to the Reference Mission, The accompanying discussions explain the rationale for making these changes. This paper also highlights those elements of the Reference Mission that were retained as beneficial to the human exploration of Mars. C1 NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Planetary Miss & Mat Branch, Houston, TX 77058 USA. RP Joosten, BK (reprint author), NASA, Lyndon B Johnson Space Ctr, Earth Sci & Solar Syst Explorat Div, Planetary Miss & Mat Branch, Code SN2, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 257 EP 274 PN 1-2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800017 ER PT S AU Lyons, DT AF Lyons, DT BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Mars global surveyor: Aerobraking with a broken wing SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Mars Global Surveyor spacecraft was launched successfully on November 7, 1996, on a Delta II 7925. During the initial spacecraft deployment, one of the two solar wings failed to deploy far enough to latch into place. The unlatched configuration was a serious problem because Mars Global Surveyor will use an aerobraking phase much like that used to circularize the orbit of the Magellan spacecraft at Venus. The solar wings supply most of the surface area that provides the drag that will result in a total Delta V of more than 1200 m/s during the four-month aerobraking phase. Aerodynamic moments at the unlatched hinge can be larger than 500 in-lb. Since the 60 in-lb spring force which is holding the unlatched panel in position for the planned aerobraking configuration is clearly not large enough, a new configuration had to be developed for the aerobraking phase. This paper will describe the redesigned aerobraking phase, which will begin on September 17, 1997 3 orbits after a 980 m/s propulsive maneuver captures the MGS spacecraft into a 45 hour, 300 km periapsis altitude orbit around Mars on September 12, 1997 (01:26 UTC). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lyons, DT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 275 EP 294 PN 1-2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800018 ER PT S AU Gramling, CJ Lee, T Niklewski, DJ Long, AC AF Gramling, CJ Lee, T Niklewski, DJ Long, AC BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Relative navigation for autonomous formation flying of spacecraft SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Goddard Space Flight Center Flight Dynamics Division has flight demonstrated the Onboard Navigation System (ONS) for high accuracy autonomous navigation using the National Aeronautics and Space Administration's Tracking and Data Relay Satellite System (TDRSS) and/or ground station command carrier signals. As a result of this success, the TDRSS version of ONS (TONS) was selected to fly as the operational navigation system on the Earth Observing System-AM1 spacecraft, ONS configurations have recently been extended to process low-Earth-orbit intersatellite tracking data to support the relative navigation between two or more spacecraft flying in an autonomously controlled formation, This paper discusses the performance of the ONS for relative navigation of the Earth-Observing-1 (EO-1)/Landsat-7 (L-7) spacecraft formation, evaluated as a function of tracking measurement type and quality, tracking frequency, and relative orbital geometry. C1 NASA, Goddard Space Flight Ctr, Flight Mech Branch, Greenbelt, MD 20771 USA. RP Gramling, CJ (reprint author), NASA, Goddard Space Flight Ctr, Flight Mech Branch, Code 552, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 435 EP 450 PN 1-2 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800027 ER PT S AU Bhaskaran, S Riedel, JE Synnott, SP AF Bhaskaran, S Riedel, JE Synnott, SP BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Autonomous nucleus tracking for comet/asteroid encounters: The STARDUST example SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB STARDUST is a mission to flyby the comet Wild-a in early 2004 and return samples of the coma to Earth. During its 120-150 km flyby of the comet nucleus, a secondary science goal is to obtain images of the nucleus using the onboard navigation camera. Due to the 40 minute round-trip light time, ground processing of navigation data to update pointing information to maintain the nucleus in the camera field-of-view is impractical. Thus, a simple, reliable, and fast algorithm was developed to close the navigation loop onboard during encounter. The algorithm uses images of the nucleus during approach to update target relative state information. This involves centroiding on the image to obtain nucleus center-of-figure data and then processing the data through a Kalman filter to update the spacecraft position and attitude. Monte Carlo simulations were then performed to test the algorithm. These simulations incorporated errors in spacecraft initial position and in attitude knowlede to provide a "truth" model which the filter must recover from. The results of the simulations proved that the algorithm was successful in maintaining the nucleus in the camera field-of-view assuming nominal values for the error sources. Even with worst case errors, the algorithm performed successfully in over 90% of the cases. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Bhaskaran, S (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr,MS 301-150, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 451 EP 468 PN 1-2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800028 ER PT S AU Keating, GM Leary, JC Green, BD Uy, OM Benson, RC Erlandson, RE Phillips, TE Lesho, JC Boies, MT AF Keating, GM Leary, JC Green, BD Uy, OM Benson, RC Erlandson, RE Phillips, TE Lesho, JC Boies, MT BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Neutral and ion drag effects near the exobase: MSX satellite measurements of He and O+ SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The winter helium bulge near the exobase was first discovered from measurements in the helium regime by a series of spherical drag satellites, Explorers 9, 19, 24, and 39 (Keating and Prior, 1967). The DOD's Midcourse Space Experiment (MSX) satellite, launched in 1996 during solar minimum, flies in a near polar circular orbit at approximately 900 km in the helium regime of the terrestrial upper atmosphere. Near 900 km, the MSX neutral mass spectrometer indicates that the winter helium bulge has a winter to summer pole amplitude near 10 at solar minimum. These are the highest circular orbit mass spectrometer measurements of the helium bulge. The very low helium densities detected near the summer pole increases the required drag effects of atomic oxygen in order to be in accord with drag measurements of total atmospheric densities. It is found that atomic oxygen drag effects near the summer pole estimated by the MSIS and Jacchia 71 models are an order of magnitude less than what is required to explain the total observed density. Measurements from the MSX ion mass spectrometer indicate O+ concentrations near the summer pole are about a factor of 10 higher than the estimated neutral atomic oxygen. Combining the MSX measurements of He and O+ gives results at 900 km consistent with previous atmospheric drag measurements of total density. Thus, at these altitudes, the major drag effect is helium at the winter pole, but O+ drag predominates at the summer pole. The transition from thermal O to O+ as the principal oxygen species apparently occurs near 750 km in the summer hemisphere. Thus, the long standing discrepancy concerning the high amplitude winter helium bulge estimated from low altitude mass spectrometer measurements and the low amplitude bulge estimated from high altitude drag measurements is finally resolved, taking into account O+ drag effects. C1 George Washington Univ, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Keating, GM (reprint author), George Washington Univ, NASA, Langley Res Ctr, MS 269, Hampton, VA 23681 USA. RI Erlandson, Robert/G-2767-2015 NR 0 TC 6 Z9 6 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 549 EP 556 PN 1-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800034 ER PT S AU Lichten, SM Wu, SC Young, LE Srinivasan, JM Haines, BJ Coulson, P AF Lichten, SM Wu, SC Young, LE Srinivasan, JM Haines, BJ Coulson, P BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI New techniques for orbit determination of geosynchronous, geosynchronous-transfer, and other high-altitude Earth orbiters SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper explores two innovative approaches to high-altitude orbit determination. GPS-enhanced tracking (GET), which has been field-tested by JPL with two geosynchronous satellites, utilizes inexpensive ground terminals developed from commercial GPS receivers. The second approach involves tracking GPS directly onboard, soon to be tested by JPL with a new microGPS receiver, also known as the Bit Grabber GPS Space Receiver (BGGSR), requiring < 0.1 watt average power. First BGGSR launch is anticipated in fall 1997. A 1999 launch is planned for STRV-1C in geosynchronous-transfer orbit to track GPS over a wide altitude range. The paper discusses observed and predicted positioning results from ground and space data analysis for these new techniques. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lichten, SM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 1153 EP 1170 PN 1-2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800073 ER PT S AU Wu, SC Kuang, D Lichten, SM Nandi, S Romans, LJ Srinivasan, JM AF Wu, SC Kuang, D Lichten, SM Nandi, S Romans, LJ Srinivasan, JM BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI Demonstration of microGPS for low-cost orbit determination SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The capability of low-cost orbit determination with a microGPS space receiver for a low earth satellite, SNOE, is demonstrated using actual GPS data from the OPS/MET satellite. The measurements acquired by the microGPS receiver will be snapshots of carrier doppler and ambiguous pseudorange. Among the challenges in orbit determination are the resolution of the pseudorange ambiguity, the estimation of the measurement timetag drift which affects the in-track orbit position solution, and the convergence of orbit solution from a cold start with essentially no knowledge of the orbit. The effects of data gaps and doppler data quality are investigated. An efficient data acquisition scenario for SNOE is derived. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wu, SC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 1537 EP 1548 PN 1-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800096 ER PT S AU Richon, KV Mathews, MW AF Richon, KV Mathews, MW BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI An overview of the Microwave Anisotropy Probe (MAP) trajectory design SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The goal of the Microwave Anisotropy Probe (MAP) is to produce an accurate full-sky map of the cosmic microwave background temperature fluctuations (anisotropy). The mission orbit is a Lissajous orbit about the L2 Sun-Earth Lagrange point. Mission duration is 27 months, with 3 months of transfer time to the L2 orbit. Trajectory maneuvers are required during the phasing loops and for stationkeeping at the mission orbit. Telemetry, tracking and command will be provided by the NASA Deep Space Network (DSN). This paper summarizes the trajectory design analysis performed by the Flight Dynamics analysts from the initial feasibility analysis to mid-1997. Selection of the mission orbit and the transfer trajectory phasing loop approach is discussed. The impacts of mission requirements and constraints on the trajectory design are examined, including the fuel budget, the launch vehicle, the launch window, and constraints from the power, thermal and communications systems. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Richon, KV (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 1979 EP 1998 PN 1-2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800121 ER PT S AU Vincent, MA AF Vincent, MA BE Hoots, FR Kaufman, B Cefola, PJ Spencer, DB TI A new method of determining orbit lifetime probabilities for use in planetary protection analysis SO ASTRODYNAMICS 1997 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY AUG 04-07, 1997 CL SUN VALLEY, ID SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB A new statistical method was derived to model the long-term behavior of the Martian atmosphere and its effect on a satellite's orbital lifetime. It was successfully used to lower the requirement for the initial quarantine orbit for the Mars Global Surveyor mission to 427 km from the 450 km dictated using conventional methods. A detailed description of the general method will be presented along with how it fits in with the general propagation models used for mission design. The results for MGS will be presented for a variety of input parameters and modeling assumptions. Future applications include other missions and problems in completely different fields, such as species extinction in ecology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vincent, MA (reprint author), CALTECH, Jet Prop Lab, MS 301-180,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-441-9 J9 ADV ASTRONAUT SCI PY 1998 VL 97 BP 2115 EP 2124 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BK64Z UT WOS:000072955800128 ER PT B AU Pence, W AF Pence, W BE Albrecht, R Hook, RN Bushouse, HA TI New developments in the FITSIO and fv software packages SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VII (ADASS) SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Conference of the Astronomical Data Analysis Software and Systems (ADASS) CY SEP 14-17, 1997 CL SONTHOFEN, GERMANY SP European So Observ, European Space Agcy, Space Telescope European Coordinating Facil, Space Telescope Sci Inst, Natl Radio Astron Observ, Sun Microsyst Detuschland, CREASO, Sybase Serv, Pink Aviat Serv AB The FITSIO subroutine library for reading and writing FITS format files was last described in the ADASS IV conference proceedings. Since then there have been many significant improvements that are outlined in this paper. Similarly, recent improvements to the fv FITS file viewer and editor are described to update the previous paper in the ADASS VI proceedings. Both packages are available from the HEASARC Web page at http://heasarc.gsfc,nasa.gov/docs/HHPsw.html. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pence, W (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-65-1 J9 ASTR SOC P PY 1998 VL 145 BP 97 EP 98 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74V UT WOS:000076551000022 ER PT B AU Antunes, A Saunders, A Hilton, P AF Antunes, A Saunders, A Hilton, P BE Albrecht, R Hook, RN Bushouse, HA TI Astro-E's mission independent scheduling suite SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VII (ADASS) SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Conference of the Astronomical Data Analysis Software and Systems (ADASS) CY SEP 14-17, 1997 CL SONTHOFEN, GERMANY SP European So Observ, European Space Agcy, Space Telescope European Coordinating Facil, Space Telescope Sci Inst, Natl Radio Astron Observ, Sun Microsyst Detuschland, CREASO, Sybase Serv, Pink Aviat Serv AB The next generation of Mission Scheduling software will be cheaper, easier to customize for a mission, and faster than current planning systems. TAKO ("Timeline Assembler, Keyword Oriented", Or in Japanese, "octopus") is our in-progress suite of software that takes database input and produces mission timelines. Our approach uses openly available hardware, software, and compilers, and applies current scheduling and N-body methods to reduce the scope of the problem. A flexible set of keywords lets the user define mission-wide and individual target constraints, and alter them on-the-fly. Our goal is that TAKO will be easily adapted for many missions, and will be usable with a minimum of training. The especially pertinent deadline of Astro-E's launch motivates us to convert theory into software within 2 years. The design choices, methods for reducing the data and providing flexibility, and steps to get TAKO up and running for any mission are discussed. C1 Hughes STX, Goddard Space Flight Ctr, Laurel, MD 20707 USA. RP Antunes, A (reprint author), Hughes STX, Goddard Space Flight Ctr, Laurel, MD 20707 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-65-1 J9 ASTR SOC P PY 1998 VL 145 BP 263 EP 266 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74V UT WOS:000076551000060 ER PT B AU Shopbell, PL Cohen, JG Bergman, L AF Shopbell, PL Cohen, JG Bergman, L BE Albrecht, R Hook, RN Bushouse, HA TI Remote observing with the Keck telescope: ATM networks and satellite systems SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VII (ADASS) SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Conference of the Astronomical Data Analysis Software and Systems (ADASS) CY SEP 14-17, 1997 CL SONTHOFEN, GERMANY SP European So Observ, European Space Agcy, Space Telescope European Coordinating Facil, Space Telescope Sci Inst, Natl Radio Astron Observ, Sun Microsyst Detuschland, CREASO, Sybase Serv, Pink Aviat Serv AB As a technical demonstration project for the NASA Advanced Communications Technology Satellite (ACTS), we have implemented remote observing on the 10-meter Keck II telescope on Mauna Kea from the Caltech campus in Pasadena. The data connection consists of ATM networks in Hawaii and California, running at OC-l speeds (45 Mbit/sec), and high data rate (HDR) satellite antennae at JPL in Pasadena and Tripler Army Medical Center in Honolulu. The ACTS network is being used to enable true remote observing, as well as remote eavesdropping. The software environment is identical to that used for on-site observing at the Keck telescope, with the added benefit of the software, personnel, and other facilities provided by observing in a local environment. In this paper, we describe our high-speed remote observing network, assess the network's level of performance, and summarize the benefits and difficulties encountered in this project. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Shopbell, PL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-65-1 J9 ASTR SOC P PY 1998 VL 145 BP 348 EP 351 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74V UT WOS:000076551000081 ER PT B AU McGlynn, T White, N AF McGlynn, T White, N BE Albrecht, R Hook, RN Bushouse, HA TI Astrobrowse: A multi-site, multi-wavelength service for locating astronomical resources on the Web SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VII (ADASS) SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 1997 Conference of the Astronomical Data Analysis Software and Systems (ADASS) CY SEP 14-17, 1997 CL SONTHOFEN, GERMANY SP European So Observ, European Space Agcy, Space Telescope European Coordinating Facil, Space Telescope Sci Inst, Natl Radio Astron Observ, Sun Microsyst Detuschland, CREASO, Sybase Serv, Pink Aviat Serv AB We report on the development of a Web agent which allows users to conveniently find information about specific objects or locations from astronomical resources on the World Wide Web. The HEASARC Astro-browse agent takes a user-specified location and queries up to hundreds of resources on the Web to find information relevant to the given target or position. The current prototype implementation is available through the HEASARC and provides access to resources at the HEASARC, CDS, CADC, STScI, IPAC, ESO and many other institutions. The types of resources the user can get include images, name resolution services, catalog queries or archive indices. The Astrobrowse effort is rapidly evolving with collaborations ongoing with the CDS and STScI. Later versions of Astrobrowse will use the GLU system developed at CDS to provide a distributable database of astronomy resources. The Astrobrowse agent has been written to be customizable and portable and is freely available to interested parties. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McGlynn, T (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 10 Z9 10 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-65-1 J9 ASTR SOC P PY 1998 VL 145 BP 481 EP 484 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74V UT WOS:000076551000111 ER PT S AU Grogan, RL Blackwood, GH Calvet, RJ AF Grogan, RL Blackwood, GH Calvet, RJ BE Reasenberg, RD TI Optical delay line nanometer level pathlength control law design for space-based interferometry SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE delay line; active optics control; interferometry; space interferometry mission; interferometry technology AB This article is concerned with the discussion of a control law design for a brassboard optical delay line (ODL) developed for the Interferometry Technology Program at the Jet Propulsion Laboratory to support the space-based optical interferometry missions. Variations on the ODL brassboard design will be flown on the Space Interferometry Mission and New Millenium Separated Spacecraft Interferometer (or Deep Space 3). The brassboard ODL was designed to meet both the performance and environmental requirements for space interferometry. A control experiment was contrived to evaluate how well the brassboard optical delay line can control optical pathlength jitter. Fringe visibility resolution requirements for space interferometry prescribe that the optical pathlength from the two collecting telescope apertures must be equal and stable to within a few nanometers RMS. This paper describes the classical frequency domain loop shaping techniques that were used to design a control law for the experiment. included is a description of a methodology for managing the control authority for the three actuation stages of the ODL, as well as, an input shaping technique for handling the large (1e9) dynamic range issues. Experimental performance results characterizing closed loop control of residual optical jitter in an ambient laboratory environment are reported. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grogan, RL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 14 EP 25 DI 10.1117/12.317176 PN 1-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300002 ER PT S AU Korechoff, RP Shaklan, SB Lin, Y Bartos, RD Moore, DM AF Korechoff, RP Shaklan, SB Lin, Y Bartos, RD Moore, DM BE Reasenberg, RD TI Design and performance of an astrometric beam combiner for space interferometry SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; beam combiner; SIM AB This paper describes the design and performance of a brassboard astrometric beam combiner. The beam combiner mas developed as part of the JPL Interferometry Technology Program (ITP). The put-pose of this program is to test out design concepts in hardware that will eventually be used for the Space Interferometry Mission (SIM). The label brassboard implies that the beam combiner is flight-like in terms of fit and function. The beam combiner met its design performance except for fringe visibility. Although it has not been environmentally tested as an assembly, the beam combiner was designed to survive the appropriate thermal and vibration tests. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Korechoff, RP (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 26 EP 34 DI 10.1117/12.317177 PN 1-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300003 ER PT S AU Calvet, RJ Joffe, B Moore, DM Grogan, RL Blackwood, GH AF Calvet, RJ Joffe, B Moore, DM Grogan, RL Blackwood, GH BE Reasenberg, RD TI Enabling design concepts for a flight-qualifiable optical delay line SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; space; optical delay line; design; flight-qualifiable; SIM AB In an interferometer, an Optical Delay Line (ODL) must be able to inject a commanded pathlength change in incoming starlight as it proceeds from a collecting aperture to the beam combiner. Fringe visibility requirements for space interferometry prescribe that the optical pathlength difference between the two arms must be equal and stable to less than 5 nm RMS to a bandwidth of 1 kHz. For a space mission, an ODL must also operate in a vacuum for years, survive temperature extremes, and survive the launch environment. As part of the Interferometer Technology Program (ITP) at Jet Propulsion Laboratory, a prototype ODL was designed and built to meet typical space mission requirements. It has survived environmental testing at flight qualification levels, and control design studies indicate the 5 nm RMS pathlength stability requirement can be met. The design philosophy for this ODL was to create as many design concepts as possible which would allow a priori attainment of requirements, in order to minimize analysis, testing, and reliance on workmanship. Many of these concepts proved to be synergistic, and many attacked more than one requirement. This paper reviews the science and flight qualification requirements for the ITP ODL and details design concepts used to meet these requirements. Examples of hardware implementations are given, and general applicability to the field of optomechanics will be noted. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Calvet, RJ (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 35 EP 47 DI 10.1117/12.317178 PN 1-2 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300004 ER PT S AU Bambery, RJ AF Bambery, RJ BE Reasenberg, RD TI The SIM science Data Center prototype: An integral element of the SIM end-to-end testbed SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ AB The Space Interferometry Mission (SIM) will be the first flight of an optical interferometer where the scientific return is co-equal with technology development objectives. The SIM Science Data Center (SDC) will be designed to monitor, process and archive the instrument engineering and science data collected over the five year operational life of the mission. Furthermore, it will host the postprocessing to be carried out for three years after the end of mission operations. Since the instrument is a complex technological and operations challenge, and due to SIM's ambitious astrometry and imaging goals, a prototype Science Data Center will be built and operated in parallel with the development of the instrument. In particular, this prototype system will be tested with SIM System Testbed-3 (STB-3) to command and monitor that instrument. After launch the SLM Science Data Center will continue to have access to STB-3 for testing of sequences and instrument operations modes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bambery, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 48 EP 57 DI 10.1117/12.317179 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300005 ER PT S AU Baron, RL Milman, MH Aaron, KM AF Baron, RL Milman, MH Aaron, KM BE Reasenberg, RD TI SIM vs. SOS: A space interferometry trade study SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE trade-study; Space Interferometry Mission (SIM); interferometry; micro-arcsecond; Jet Propulsion Laboratory; Son of SIM; (SOS); delay line; Laser Metrology AB This study was undertaken at the Jet Propulsion Laboratory to identify salient features of two competing instrument designs and to select the design that best meets the goals of the Space Interferometry Mission. Features were examined in terms of meeting performance, cost, schedule and risk requirements. The study included the spacecraft, the space environment, metrology considerations, stabilization of optics with temperature, spacecraft structure, complexity, and end-to-end testing among other items. The most significant determinant was the fundamental implementation of the instrument's metrology system. The impact on the testbed program associated with the mission was considered the second most important issue. An error propagation formalism was developed to address various instrument geometries examined as part of this study. The formalism propagates metrology errors from the gauge readings through to the angle on the sky (the desired measurement of the interferometer). An introduction to the formalism is presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Baron, RL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 70 EP 80 DI 10.1117/12.317181 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300007 ER PT S AU Schmidtlin, EG Shaklan, SB Carlson, AE AF Schmidtlin, EG Shaklan, SB Carlson, AE BE Reasenberg, RD TI Novel wide field-of-view laser retroreflector for the Space Interferometry Mission SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; retroreflector; cornercube; optical fiducial; laser metrology; triangulation; optical truss AB A new type of laser retroreflector has been developed for JPL's future Space Interferometry Mission. The retroreflector consists of an assembly of prisms to form multiple hollow cornercubes. This allows the limited field of view (FOV) of about 60 degrees of a single corner can be overcome, to comply with the geometry of an optical truss. In addition, an innovative feature is that the retroreflector has common vertices, in order to define a single point optical fiducial necessary for point-to-point 3D laser metrology. The multiple cornercube provides better thermal stability and optical performance than spherical and hemispherical type retroreflectors. In manufacturing the prototype, the key technology of assembling prisms to the interferometric accuracy has been demonstrated. A non common vertex error of a few mu m has been achieved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schmidtlin, EG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 306-388, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 81 EP 88 DI 10.1117/12.317182 PN 1-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300008 ER PT S AU Carlson, A Shaklan, S Bartos, R Azevedo, S AF Carlson, A Shaklan, S Bartos, R Azevedo, S BE Reasenberg, RD TI Opto/mechanical design of the Micro-Arcsecond Metrology testbed interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometer; optical delay; metrology; precision optics; angle tracking AB The Micro Arcsecond Metrology Testbed (MAM) is a laboratory-based, long baseline, white-light interferometer inside a vibration-isolated vacuum tank. The single baseline, high precision interferometer will be able to observe a translating, artificial star at a distance of 10.74 meters with 5 mu as accuracy. The MAM testbed consists of an artificial star, laser metrology and a high precision interferometer. This paper addresses the design and characteristics of the interferometer. The interferometer functions include both angle- and optical-path tracking. The optics are arranged to form dispersed fringes in a channeled spectrum on a charge coupled device (CCD) and a true white-light fringe on an avalanche photodiode (APD), while at the same time producing guide spots for angle tracking. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Carlson, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 89 EP 99 DI 10.1117/12.317183 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300009 ER PT S AU Kuhnert, AC Shaklan, S Gursel, Y Azevedo, SL Lin, Y AF Kuhnert, AC Shaklan, S Gursel, Y Azevedo, SL Lin, Y BE Reasenberg, RD TI Metrology for the Micro-Arcsecond Metrology testbed SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometer; interferometry; metrology; picometer; heterodyne interferometer AB The Space Interferometry Mission (SIM) relies on the combination of interferometry with a metrology system capable of measuring picometer relative length changes and micrometer absolute lengths. We are designing the Micro-Arcsec Metrology Test-Bed (MAM)(1) to put these two systems together in a large vacuum tank (12 m long, 2.4 m in diameter). The interferometer has a 1.8 m baseline and is looking at an artificial star 10 m away. The metrology system is measuring the distances between the interferometer mirrors, the interferometer mirrors and the "star" (external metrology), and the interferometer arm lengths (internal metrology). We are using two common path laser heterodyne interferometers to monitor each of these distances. The light sources used are two Nd:YAG lasers with different frequencies, f(0) and f(0)+30 GHz. This allows measurement of relative lengths changes as well as absolute lengths. The design for the heterodyne interferometers is in progress using our experience from I-D End 3-D metrology experiments performed in the past. Modifications include reducing the cross-talk in the internal metrology and adding a polarizing beamsplitter to the laser light path to compensate for path lengths changes caused by temperature changes. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Kuhnert, AC (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 100 EP 108 DI 10.1117/12.317185 PN 1-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300010 ER PT S AU Loiseau, S Shaklan, S Redding, D Schmidtlin, E AF Loiseau, S Shaklan, S Redding, D Schmidtlin, E BE Reasenberg, RD TI Retroreflector diffraction modeling SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE retroreflectors; diffraction; aberrations; metrology; interferometry; astrometry AB The SIM metrology subsystem utilizes cornercube retroreflectors as fiducials. These components will introduce errors in the metrology output that must be quantified. Eventually, a complete modeling of the metrology subsystem will be needed. For that purpose, we are developing an optical model for a cornercube retroreflector, taking into account most of the defects present in such an optical part. Our goal is to give a phase map of the wavefront produced by the interference of the reference beam and the metrology beam (which suffered multiple reflections during its round-trip between the cornercubes). Our first step towards this goal is the construction of an optical model and its validation, using the MACOS and VSIM packages. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Loiseau, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 109 EP 115 DI 10.1117/12.317186 PN 1-2 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300011 ER PT S AU Gorham, PW AF Gorham, PW BE Reasenberg, RD TI Optimal filter approach to photon-limited white light fringe detection and delay rate estimation in an optical interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE optical interferometer; white light fringe; optimal filter; space-based interferometry AB We review the formalism for white light fringes in Michelson interferometers. For astronomical use, these instruments are typically limited in sensitivity by photon statistics. Thus rye investigate by simulation an alternate approach to fringe detection which utilizes an Optimal filter approach. This is compared to a highly successful method presently used in many such systems, based on quadrature fringe amplitude. It is found that the optimal filter approach yields an improved sensitivity of between 0.3 and 0.8 visual stellar magnitudes. We also consider the possibility of using such an approach to search over trial values of fringe drift rate, corresponding to linear motion of the fringe. We find that a very significant improvement in performance is possible for systems that utilize searches over both delay and delay rate. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Gorham, PW (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 116 EP 127 DI 10.1117/12.317187 PN 1-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300012 ER PT S AU Joshi, SS Neat, GW AF Joshi, SS Neat, GW BE Reasenberg, RD TI Lessons learned from multiple fidelity modeling of ground interferometer testbeds SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometer; MPI; modeling; IMOS AB The MicroPrecision Interferometer Testbed (MPI) at JPL is a dynamically and dimensionally representative hardware model of a future spaceborne optical interferometer.(1) Over the past few years, several models of MPI have been created. These include detailed, high-fidelity models of MPI and several lower-fidelity models. These models were meant to answer two basic questions: (1) "Does current modeling methodology allow accurate models of highly complex opto-mechanical systems such as the MPI testbed?" and (2) "Given a valid modeling methodology, how much model fidelity is needed in models to accurately predict performance?". In order to answer these questions, four models of the MPI testbed were created; each with a unique optical and structural model fidelity. This paper reviews results obtained from these models. It compares disturbance transfer function predictions from three of the models with measured disturbance transfer functions from the hardware testbed. (The fourth model, not discussed here, quantifies the effects of model-updating using both modal and in-situ component testing.) Results suggest that it is possible to build a highly accurate high-fidelity model, thus validating the modeling methodology. With lower fidelity models, meaningful model prediction errors exist when simple models are used to represent the complex opto-mechanical system. However, modest increases in model fidelity can lead to significant improvement. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Joshi, SS (reprint author), CALTECH, Jet Prop Lab, MS198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 128 EP 138 DI 10.1117/12.317188 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300013 ER PT S AU Turyshev, SG AF Turyshev, SG BE Reasenberg, RD TI Relativity studies with high precision astrometry SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE relativity; gravitational theory; astrometry; solar system dynamics AB The last decade of the 20-th century has seen the development of extremely sensitive instruments based on new emerging technologies. These instruments, which are widely distributed on Earth and currently being deployed in space, have provided the means necessary to probe more deeply into the nature and evolutionary history of the universe. Together with a noticeable progress in providing a less expensive launch services, this made a significant impact on a number of areas of fundamental research. One of such areas is the research in relativistic and gravitational physics. Motivated by the opportunities offered by the future Space Interferometry Mission, we discuss high-precision astrometric measurements and their significance for the relativistic gravitational theory. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Turyshev, SG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 139 EP 145 DI 10.1117/12.317189 PN 1-2 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300014 ER PT S AU Irwin, PC Goullioud, R AF Irwin, PC Goullioud, R BE Reasenberg, RD TI Hardware design and object-oriented hardware driver design for the Real-time Interferometer Control System Testbed (RICST) SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ AB Since modern astronomical Interferometers require a large number of sensors and actuators for closed-loop control of opto-mechanical components, reconfigurability of the hardware is a strongly desired feature of interferometer control software. In order for software control systems to access hardware with a standard interface and be easily reconfigurable, a layer of software is needed to communicate with the hardware while hiding the details of the specific I/O boards. There are significant advantages to designing hardware driver software that is modular. If the details of the hardware configuration can be abstracted from the controller software, moving a device to a different I/O board or channel becomes a much easier task. Device mobility is important when testing the performance of computer and instrument hardware, and controller software; it also makes the software much easier to reuse in different instruments. Object-oriented programming provides a model that permits the abstraction of this hardware driver layer. The Jet Propulsion Laboratory's Realtime Interferometer Control System Testbed (RICST) has developed hardware driver software that employs an object-oriented paradigm and allows relatively simple reconfigurability of devices and I/O boards. This scheme is especially useful since RICST is developing software for use by multiple projects. The top lever of the class hierarchy includes Boards, Channels, Channel Banks, Clocks, and Interrupts these abstract objects provide a common interface for central software to communicate with the hardware. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Irwin, PC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 146 EP 152 DI 10.1117/12.317190 PN 1-2 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300015 ER PT S AU Johnson, RL McKenney, EA Starr, KM AF Johnson, RL McKenney, EA Starr, KM BE Reasenberg, RD TI Real-time control software for optical interferometers: The RICST testbed SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometer control; real-time software; gizmo; inter-processor communication; servo; controller; telemetry AB RICST (pronounced "rixt"), the Realtime Interferometer Control System Testbed, is a testbed at NASA's Jet Propulsion Laboratory where teams are developing a common electronics and software foundation that will form the core of the control system for JPL's various interferometer projects. Important technologies being developed and demonstrated on the RICST testbed include hard real-time multiprocessing, generic interferometer software and hardware architecture, easy reconfigurability, abstract constructs for easy implementation of control loops and servos, and highly configurable telemetry streams. The basic hardware and software architecture developed by RICST can be applied to virtually any interferometer based on the combiner-collector architecture. The RICST project began in May 1996 and has been delivering control system "increments" every few months since that time. Each increment adds new end-to-end functionality. White-light fringe tracking has been demonstrated in the lab already; the delivery of a fully operational testbed is scheduled for the end of April. Future enhancements will add support for a wide array of calibration, sequencing, and other support functions. RICST deliveries include support software, such as a graphical user interface and a prototype spacecraft bus interface, as well as the embedded software needed to run the instrument. The RICST program will make final deliveries to its various customers in 2000, after which the RICST testbed facility will continue on in support of the SIM mission. C1 Jet Prop Lab, Pasadena, CA 91009 USA. RP Johnson, RL (reprint author), Jet Prop Lab, Pasadena, CA 91009 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 153 EP 162 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300016 ER PT S AU Blackwood, GH Dubovitsky, S Linfield, RP Gorham, PW AF Blackwood, GH Dubovitsky, S Linfield, RP Gorham, PW BE Reasenberg, RD TI Interferometer instrument design for new millennium deep space 3 SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE space-based optical interferometry; formation flying; metrology; active optics; Michelson interferometer AB Deep Space 3 will fly a stellar optical interferometer on three separate spacecraft in heliocentric orbit: one spacecraft for the Michelson beam combining optics, and two spacecraft for each of the starlight apertures. The spacecraft will formation fly to relative spacecraft distances from 100 meters to 1 :kilometer, enabling an instrument resolution of 1 to 0.1 milliarcsecond. At each baseline length and orientation-up to 100 points in the synthetic aperture plane for a given astrophysical target-the instrument will measure source visibility amplitude from which the source brightness distribution can be determined. An infrared metrology system performs both linear and angular metrology between spacecraft and is used to estimate delay jitter, interferometer delay and delay rate. Pointing and control mechanisms use the metrology error signals to stabilize delay jitter and to null delay and delay rate to enable detection and tracking of a white light fringe on a photon-counting detector. Once stabilized, fringes can be dispersed on a CCD in up to 80 spectral channels to attain high-accuracy measurements of visibility amplitude as a function of wavelength. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Blackwood, GH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 173 EP 183 DI 10.1117/12.317194 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300018 ER PT S AU Vasisht, G Boden, AF Colavita, MM Crawford, SL Shao, M Swanson, P van Belle, GT Wallace, JK Walker, JM Wizinowich, PL AF Vasisht, G Boden, AF Colavita, MM Crawford, SL Shao, M Swanson, P van Belle, GT Wallace, JK Walker, JM Wizinowich, PL BE Reasenberg, RD TI Aperture synthesis imaging with the Keck interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; SPIE Proceedings; Keck; synthesis imaging AB JPL and CARA are building a multi-element, infrared interferometer for NASA to be situated at the twin Keck Observatories on Mauna Kea, Hawaii. Initially, the IO-m diameter Keck telescopes will be augmented with four fixed-location 2-m class outrigger telescopes resulting in 15 non-redundant baselines, the longest being similar or equal to 110 m or nearly 5 x 10(7) (lambda/2.2 mu m)(-1) wavelengths. Fast adaptive optics and tip-tilt corrections will be used to phase up the Keck and outrigger apertures, respectively. The entire array will be cc-phased by observing a relatively bright target on the photon rich Keck-Keck (K-K) and Keck-outrigger (K-O) baselines. When fully phased, the projected fringe phasor sensitivity for unresolved targets will be K similar to 22.0, 20.0 and 17.9 (10-sigma in 10(3) s) on the K-K, K-O and O-O baselines, respectively Synthetic imaging capability will be available in the 1.6 - 10.0 mu m atmospheric transmission bands at angular resolutions of 4.0(lambda/2.2 mu m) milli-arcseconds. In this article, we briefly outline the adopted methodology, imaging hardware, projected sensitivities and summarize the scientific potential of the instrument as an imaging interferometer. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vasisht, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 354 EP 361 DI 10.1117/12.317097 PN 1-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300037 ER PT S AU van Belle, GT Boden, AF Colavita, MM Shao, M Vasisht, G Wallace, JK AF van Belle, GT Boden, AF Colavita, MM Shao, M Vasisht, G Wallace, JK BE Reasenberg, RD TI Astrometry with the Keck interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE astrometry; interferometry; Keck; extrasolar planets; MACHOs AB A key thrust of NASA's Origins program is the search for and detection of planetary systems about other stars. Pursuing this goal in a cost-effective and expedient manner from the ground has led NASA to begin work on the Keck Interferometer, which will add 4 1.8m 'outrigger' telescopes at the Keck Observatory on Mauna Kea. In addition to the imaging science to be performed by the Keck 10m telescopes with the outriggers, another one of the principal capabilities of. the instrument will be the ability for the outriggers to conduct relative astrometry at the 25 microarcsecond level per root hour. Astrometry of this accuracy will enable the array to detect planetary systems composed of Uranus-mass or larger bodies orbiting at 5 AU solar mass stars at a distance of 20 pc; over 300 stars are to be surveyed by the outriggers annually. The astrometric capabilities of the Keck array can also be utilized other astrophysical investigations, such as characterization of spectroscopic binary orbits, and the measurement of the center-of-light shift of MACHO microlensing events, which will allow for a model-independent determinations of lens masses. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP van Belle, GT (reprint author), CALTECH, Jet Prop Lab, MS 171-113, Pasadena, CA 91109 USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 362 EP 372 DI 10.1117/12.317098 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300038 ER PT S AU Shao, N AF Shao, N BE Reasenberg, RD TI SIM the space interferometry mission SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; astrometry; exoplanet detection AB SIM is the first of the new Origins missions that combines major advances in technology to enable major advances in science. This paper is a brief overview of the project to serve as an introduction to the many other technical papers presented at this conference. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shao, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 33 Z9 33 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 536 EP 540 DI 10.1117/12.317092 PN 1-2 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300060 ER PT S AU Unwin, SC Turyshev, SG Shao, M AF Unwin, SC Turyshev, SG Shao, M BE Reasenberg, RD TI Science with the space interferometry mission SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE astrometry; astronomy; astrophysics; Galaxy; interferometry; parallax AB The Space Interferometry Mission (SIM) will be NASA's first space-based optical interferometer. SIM will produce a wealth of new astronomical data and serve as a technology pathfinder for future astrophysics missions. The SIM architecture uses a 10-m Michelson interferometer in Earth-trailing solar orbit to provide 4 microarcsecond (mu as) precision absolute position measurements of stars down to 20 magnitude. The corresponding parallax accuracy allows distance measurements to 10% accuracy on the far side of the Galaxy. With high-precision proper motions derived during its 5-year lifetime, SIM will address a variety of science questions relating to the formation and dynamics of our Galaxy. Using aperture synthesis, SIM mill image in the visible waveband to a resolution of 10 milliarcsec, and will demonstrate interferometric nulling with suppression of the on-axis starlight to a level of 10(-4). In this paper we present selected topics from the SIM science program focusing on some specific astronomical questions to be addressed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Unwin, SC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 551 EP 560 DI 10.1117/12.317144 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300062 ER PT S AU Gursel, Y AF Gursel, Y BE Reasenberg, RD TI Metrology for spatial interferometry V SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ AB The proposed Space Interferometry Mission (SIM) spacecraft designs include high resolution stellar interferometers for micro-are-second accuracy astrometric measurements. These stellar interferometers require picometer accuracy one dimensional metrology gauges, surface metrology gauges and 3-dimensional metrology gauges to measure the required distances or to calibrate the fiducials that define the end points of the interferometric paths. The absolute metrology gauges required by these interferometers can be considerably less accurate due to the careful design of the astrometric interferometers and the fiducials on the spacecraft. An auto-aligning, 3-dimensional metrology gauge constructed using the sub-picometer linear metrology gauges was described in earlier papers. The sub-nanometer, in-vacuum tracking results from this 3-dimensional metrology gauge are presented. The resulting jitter is analyzed and is shown to be caused by thermal drift in the alignment of the gauge heads, warpage of the base table and the time-dependent tilt of the experiment as a whole. The aberrations in the light beams of the laser distance gauges can result in errors in the distance measurements performed using these gauges. Simulations using spot shapes and aberrations present in a realistic measurement system used in a stellar interferometer in space are performed to quantify the amount of expected errors. The results of these simulations are presented. Open-faced, hollow corner cube retroreflectors are traditionally used as fiducials in the one-dimensional relative and absolute metrology gauges and the 3-dimensional metrology gauge. These are narrow field of view fiducials that can not accomodate interferometers that need access over much wider fields of view. Attempts had been made to increase the field of view of these fiducials by putting several of them together on the same block of glass(6) (7). These designs have not achieved a common corner co-location of better than 1 mu m due to purely technical, but hard to overcome difficulties. A solid glass, one piece, 4 pi steradian field of view and easy to manufacture fiducial design is presented that allows common corner co-location within few tens of nanometers. The spatial and temporal stability of the common corner is achieved by carefully controlling the fiducial temperature drift and jitter to less than 1 millidegree Celcius. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gursel, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 13 Z9 13 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 571 EP 587 DI 10.1117/12.317175 PN 1-2 PG 17 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300064 ER PT S AU Aaron, KM Mateer, WH Baron, RL AF Aaron, KM Mateer, WH Baron, RL BE Reasenberg, RD TI SIM configuration trades SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE classic; SIM; space Interferometry; SOS; JPL; astrometry AB The Space Interferometry Mission (SIM) will perform astrometry to a resolution of a few micro are seconds (after post-processing on the ground of the acquired data). The development of this mission is being led by the California Institute of Technology, Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration (NASA). A recent trade study was performed to compare two significantly different architectures. This paper will describe the two configurations and contrast some of their differences and similarities. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Aaron, KM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 595 EP 605 DI 10.1117/12.317122 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300066 ER PT S AU Linfield, RP Gorham, PW AF Linfield, RP Gorham, PW BE Reasenberg, RD TI Science capabilities of the DS3 mission SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE optical interferometry; space interferometry AB The DS3 mission will launch a space optical Interferometer into heliocentric orbit, for observation of 50-100 sources on baselines up to 1000-2000 m. The detection threshold will be visual magnitude 12-13, and the angular resolution in the 500-900 nm passband will be approximate to 100 microarcseconds, interesting science targets which could be imaged include: Cyg X-l, Wolf-Rayet stars, and FU Ori stars. With a modest improvement in sensitivity, the structure of the broad Line emission regions of a few bright AGNs could be measured. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Linfield, RP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 608 EP 615 DI 10.1117/12.317093 PN 1-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300067 ER PT S AU Dubovitsky, S Linfield, RP Blackwood, GH Gorham, PW Shao, M Folkner, WM Yu, JW AF Dubovitsky, S Linfield, RP Blackwood, GH Gorham, PW Shao, M Folkner, WM Yu, JW BE Reasenberg, RD TI Deep Space 3 metrology system SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE space-based stellar interferometry; separated spacecraft interferometer; interferometric metrology; frequency modulated metrology AB A metrology subsystem on board the Deep Space 3, a separated spacecraft interferometer mission, is used to determine stellar fringe delay jitter, delay rate, and initial delay. The subsystem implements two capabilities: linear metrology for optical pathlength determination and angular metrology needed to determine the configuration and orientation of the spacecraft constellation. Frequency modulated metrology concept is used to implement high-precision (5 nm) interferometric linear measurements over large target ranges (1 km). System is made angle sensitive by using an articulated flat mirror at the target. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dubovitsky, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 616 EP 625 DI 10.1117/12.317103 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300068 ER PT S AU Hines, BE Johnson, RL Starr, KM AF Hines, BE Johnson, RL Starr, KM BE Reasenberg, RD TI Common interferometer control systems architecture SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; software; real-time control; electronics; common architecture; generic; control system AB Astronomical interferometry at the Jet Propulsion Laboratory has grown rapidly in the last two years. JPL is now engaged in a number of interferometry projects and is also developing a number of internal testbeds to support those projects. While each of these projects and testbeds has its own unique properties, they do share a lot of common features, and JPL is striving, through its Interferometer Technology Program (ITP), to develop common components, software, and hardware that can be reused by multiple projects. The discipline where this commonality is probably most apparent is in the area of realtime control systems, specifically, the software and electronics that drive the instrument control loops and sequence the subsystems. To this end, within the ITP, JPL has developed the Realtime Interferometer Central Systems Testbed (RICST) as a facility where a common software and electronics core, essentially a control system for a generic interferometer, can be developed. The Realtime Control (RTC) team in the ITP program consists of about 20 full-time equivalent engineers, technicians, quality assurance personnel, architects, and managers. The remainder of this paper will describe the interferometry landscape at JPL, the RTC effort, an overview of the RICST testbed, and the generic interferometer control systems architecture that has been developed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hines, BE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 644 EP 653 DI 10.1117/12.317136 PN 1-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300071 ER PT S AU Laskin, RA AF Laskin, RA BE Reasenberg, RD TI Technology for space optical and infrared interferometry SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometer; laser metrology; active control; vibration attenuation; integrated modeling AB Optical and infrared interferometry will open new vistas for astronomy over the next decade. Space based interferometers, operating unfettered by the Earth's atmosphere, will offer the greatest scientific payoff: They also present the greatest technological challenge: laser metrology systems must perform with sub-nanometer precision; mechanical vibrations must be controlled to nanometers requiring orders of magnitude disturbance rejection; a multitude of actuators and sensors must operate flawlessly and in concert. The Interferometry Technology Program at NASA's Jet Propulsion Laboratory is addressing these challenges with a development program that plans to establish technology readiness for the Space Interferometry Mission by early in the year 2001. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Laskin, RA (reprint author), CALTECH, Jet Prop Lab, Mail Stop 180-603, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 654 EP 664 DI 10.1117/12.317129 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300072 ER PT S AU Levine, MB AF Levine, MB BE Reasenberg, RD TI The interferometry program flight experiments: IPEX I & II SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ AB The Interferometry Program EXperiments (IPEX) I and II are a series of flight experiments designed to characterize microdynamics of structures in space. These technology demonstration flight experiments are precursors to the Space Interferometry Mission (SIM), Next Generation Space Telescope (NGST) and Terrestrial Planet Finder (TPF), and will address the missions' nanometer-level structural stability requirements. Of particular interest is potential thermal snapping when space structures undergo rapid thermal variations, such as a sun-to-shade transition. This information is needed to characterize uncontrollable high frequency disturbances,. and to validate structural designs and modeling approaches for joint-dominated extruding structures. Another objective of the experiments is to characterize typical mechanical disturbances of spacecraft while on-orbit for the purpose of modeling and disturbance response prediction for future optical space missions. Both experiments are performed on the German DARA/DASA free-flying platform Astro-Spas, which is sortied out of the shuttle and retrieved after an independent 10-day mission. IPEX-I, performed during the STS-80 mission in December 1996, characterized the on-board dynamics of the spacecraft during normal operations and quiescent periods. IPEX-II, performed during the STS-85 mission in August 1997, monitored the microdynamic behavior of a representative 9-bay AEC-ABLE mast. The flight data demonstrates the existence of transient microdynamic events that are correlated with temperature transitions. However, the overall spacecraft flight disturbances and broadband boom stability meet the requirements of precision space optical systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Levine, MB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 157-316, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 707 EP 718 DI 10.1117/12.317128 PN 1-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300078 ER PT S AU Beichman, CA AF Beichman, CA BE Reasenberg, RD TI The terrestrial planet finder: The search for life-bearing planets around other stars SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ AB The Terrestrial Planet Finder (TPF) will detect and characterize Earth-like planets around nearby stars. NASA is currently funding a number of small studies to look at trade-offs in the design of TPF. The possible trade-offs include orbit location (1 to 5 AU), aperture size (4 to 2 m), and physically connected baselines vs. separated spacecraft flying in close formation. The performance of TPF depends critically on the brightness of the local zodiacal dust cloud at the observing site, and on the brightness and degree of structure in the zodiacal dust cloud around other stars. Sensitivity calculations indicate that TPF could accomplish its goals using 4-5 m telescopes operating at 1 AU. Such a mission would have many advantages relative to a mission operating smaller telescopes in lower background conditions at 5 AU. C1 CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91109 USA. RP Beichman, CA (reprint author), CALTECH, Jet Prop Lab, IPAC, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 36 Z9 37 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 719 EP 723 DI 10.1117/12.317137 PN 1-2 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300079 ER PT S AU Colavita, MM Boden, AF Crawford, SL Meinel, AB Shao, M Swanson, PN van Belle, GT Vasisht, G Walker, JM Wallace, JK Wizinowich, PL AF Colavita, MM Boden, AF Crawford, SL Meinel, AB Shao, M Swanson, PN van Belle, GT Vasisht, G Walker, JM Wallace, JK Wizinowich, PL BE Reasenberg, RD TI The Keck Interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE optical interferometry; astrometry; nulling; synthesis imaging; exozodiacal dust; extrasolar planets AB The Keck Interferometer is being developed by JPL and CARA as one of the ground-based components of NASA's Origins Program. The interferometer will combine the two 10-m Keel; telescopes with four proposed 1.8-m outrigger telescopes located at the periphery of the Keck site on Mauna Kea. Incorporation of adaptive optics on the Keck telescopes with cophasing using an isoplanatic reference provides high sensitivity. Back-end instrumentation will include two-way combiners for cophasing and single-baseline measurements, a nulling combiner for high-dynamic range measurements, and a multi-way imaging combiner. Science objectives include the characterization of zodiacal dust around other stars, detection of hot Jupiters and brown dwarfs through multi-color differential-phase measurements, astrometric searches for planets down to Uranus-mass, and a wide range of infrared imaging. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Colavita, MM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 39 Z9 40 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 776 EP 784 DI 10.1117/12.317145 PN 1-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300086 ER PT S AU Wallace, JK Boden, AF Colavita, MM Dumont, P Gursel, Y Hines, B Koresko, C Kulkarni, S Lane, B Malbet, F Palmer, D Pan, XP Shao, M Vasisht, G van Belle, G Yu, J AF Wallace, JK Boden, AF Colavita, MM Dumont, P Gursel, Y Hines, B Koresko, C Kulkarni, S Lane, B Malbet, F Palmer, D Pan, XP Shao, M Vasisht, G van Belle, G Yu, J BE Reasenberg, RD TI Palomar Testbed Interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE optical interferometry; astrometry; extrasolar planets AB The Palomar Testbed Interferometer (PTI) is an infrared, phase-tracking interferometer in operation at Palomar Mountain since July 1995. It was funded by NASA for the purpose of developing techniques and methodologies for doing narrow-angle astrometry for the purpose of detecting extrasolar planets. The instrument employs active fringe tracking in the infrared (2.0-2.4 mu m) to monitor fringe phase. It is a dual-star interferometer; it is able to measure fringes on two separate stars simultaneously. An end-to-end heterodyne laser metrology system is used to monitor the optical path length of the starlight. Recently completed engineering upgrades have improved the initial instrument performance. These upgrades are: extended wavelength coverage, a single mode fiber for spatial filtering, vacuum pipes to relay the beams, accelerometers on the siderostat mirrors and a new baseline. Results of recent astrometry data indicate the instrument is approaching the astrometric limit as set by the atmosphere. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wallace, JK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 864 EP 871 DI 10.1117/12.317154 PN 1-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300096 ER PT S AU Boden, AF Colavita, MM van Belle, GT Shao, M AF Boden, AF Colavita, MM van Belle, GT Shao, M BE Reasenberg, RD TI Visibility calibrations with the Palomar Testbed Interferometer SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometers; calibration AB The Palomar Testbed Interferometer is a long-baseline, near-infrared astronomical interferometer capable of visibility measurement and narrow-angle differential astrometry. In this submission we consider the problem of fringe amplitude calibration as applied to the study of single and binary star systems with PTI. Methodologies for selecting appropriate calibration objects, and performing the calibrations to produce consistent multi-night datasets are considered. Applications of such calibrated datasets to binary orbit determination and stellar diameter measurements will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boden, AF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 45 Z9 45 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 872 EP 880 DI 10.1117/12.317155 PN 1-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300097 ER PT S AU Dubovitsky, S Seidel, DJ Liu, D Gutierrez, RC AF Dubovitsky, S Seidel, DJ Liu, D Gutierrez, RC BE Reasenberg, RD TI Metrology source for high-resolution heterodyne interferometer laser gauges SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE heterodyne interferometry; optical metrology; space-based metrology systems AB We describe the development, functional performance, and space-qualification status of a Metrology Source suitable for implementation of space-based metrology systems with picometer-level relative displacement measurement and micron-level absolute displacement measurement resolution. The Metrology Source consists of the following components: Lasers, frequency Stabilization System, Frequency Shifters, and Frequency Modulators. All components are interconnected by polarization maintaining fibers to facilitate integration into a lightweight space-qualifiable module. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dubovitsky, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 973 EP 984 DI 10.1117/12.317166 PN 1-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300107 ER PT S AU Gutierrez, RC Dubovitsky, S Kissa, KM Fritz, DJ AF Gutierrez, RC Dubovitsky, S Kissa, KM Fritz, DJ BE Reasenberg, RD TI Integrated optic frequency shifters for space heterodyne interferometry SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE acousto-optic tunable filter; frequency shifter; heterodyne interferometry AB Heterodyne interferometer laser gauges are used in space-based astronomical interferometers to very accurately measure and compensate for variations in starlight pathlength. Bragg cells have been traditionally used to generate the heterodyne signal by shifting the frequency of the laser light. This paper presents the development and qualification of an integrated optic frequency shifter (IOFS) which offers improved performance and reliability compared with Bragg cell technology. The most critical advantage of the IOFS for space applications is that it enables fiber optic metrology source integration, which facilitates the integration process and results in more reliable and compact heterodyne interferometer laser gauges. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gutierrez, RC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 985 EP 993 DI 10.1117/12.317167 PN 1-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300108 ER PT S AU Shaklan, S Azevedo, S Bartos, R Carlson, A Gursel, Y Halverson, P Kuhnert, A Lin, Y Savedra, R Schmidtlin, E AF Shaklan, S Azevedo, S Bartos, R Carlson, A Gursel, Y Halverson, P Kuhnert, A Lin, Y Savedra, R Schmidtlin, E BE Reasenberg, RD TI The micro-arcsecond metrology testbed (MAM) SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE interferometry; Space Interferometry Mission; astrometry AB The micro-arcsecond metrology testbed (MAM) is a high-precision long baseline interferometer inside a vibration-isolated vacuum tank. The instrument consists of an artificial star, a laser metrology system, and a single-baseline interferometer with a 1.8 m baseline and a 5 cm clear aperture. MAM's purpose is to demonstrate that the astrometric error budget specified for the Space Interferometry Mission can be met. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shaklan, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 306-388, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 1009 EP 1019 DI 10.1117/12.317192 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300111 ER PT S AU Neat, GW Abramovici, AR Calvet, RJ Korechoff, RP Joshi, SS Goullioud, R AF Neat, GW Abramovici, AR Calvet, RJ Korechoff, RP Joshi, SS Goullioud, R BE Reasenberg, RD TI Use of the Microprecision Interferometer testbed for developing control technology for spaceborne optical interferometer missions SO ASTRONOMICAL INTERFEROMETRY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Astronomical Interferometry CY MAR 20-24, 1998 CL KONA, HI SP SPIE, European So Observ DE testbed; stellar interferometry; spaceborne interferometry; controls; active optical path control; vibration attenuation AB This paper describes the Micro-Precision Interferometer (MPI) testbed and its major achievements to date related to mitigating risk for future spaceborne optical interferometer missions. The MPI testbed is a ground-based hardware model of a future spaceborne interferometer. The three primary objectives of the testbed are to: (1) demonstrate the 10 nm positional stability requirement in the ambient lab disturbance environment, (2) predict whether the 10 nm positional stability requirement can be achieved in the anticipated on-orbit disturbance environment, and (3) validate integrated modeling tools that will ultimately be used to design the actual space missions. This paper describes the hardware testbed in its present configuration. The testbed simulation model, as it stands today, will be described elsewhere. The paper presents results concerning closed loop positional stabilities at or below the 10 nm requirement for both the ambient and on-orbit disturbance environments. These encouraging results confirm that the MPI testbed provides an essential link between the extensive ongoing ground-based interferometer technology development activities and the technology needs of future spaceborne optical interferometers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Neat, GW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2797-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3350 BP 1020 EP 1030 DI 10.1117/12.317173 PN 1-2 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Optics SC Engineering; Astronomy & Astrophysics; Optics GA BL55C UT WOS:000075850300112 ER PT J AU Kissler-Patig, M Brodie, JP Schroder, LL Forbes, DA Grillmair, CJ Huchra, JP AF Kissler-Patig, M Brodie, JP Schroder, LL Forbes, DA Grillmair, CJ Huchra, JP TI Keck spectroscopy of globular clusters around NGC 1399 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, individual (NGC 1399); galaxies, star clusters; globular clusters, general ID ELLIPTIC GALAXIES; METALLICITY; SYSTEMS; DYNAMICS; M87; PHOTOMETRY; KINEMATICS; NGC-1399; VELOCITY; MASSES AB We report moderate-resolution, high signal-to-noise ratio spectroscopy of globular clusters around NGC 1399, the central cD galaxy in the Fornax Cluster. We address issues as diverse as elemental abundances of globular clusters versus stellar populations in elliptical galaxies, blue horizontal branches in metal-rich globular clusters, broadband colors as metallicity tracers, possible overestimation of the age-metallicity degeneracy in globular clusters, and dark matter in the halo of NGC 1399. We obtained spectra for 21 globular cluster candidates with multislit spectroscopy using the Low Resolution Imaging Spectrograph on the Keek I Telescope. Our sample turned out to include 18 globular clusters, one star, and two low-redshift late-type galaxies (z similar or equal to 0.3). The mean velocity of our globular cluster sample is 1293 +/- 71 km s(-1), and its velocity dispersion is 302 +/- 51 km s(-1). Both are slightly lower than, but in agreement with, previously derived values. We derive a mass of (1-5) x 10(12) M-circle dot within 28 kpc for the galaxy, and an M/L-B ratio of 36 +/- 20 or 76 +/- 40 M-circle dot/L-circle dot(B), depending on the mass estimator. Both estimates indicate that dark matter dominates the potential at 6r(eff). The derived elemental abundances for the globular clusters span the entire range observed in the Milky Way and M31, with a mean metallicity of our sample around [Fe/H] similar or equal to -0.8 dex. This implies that the two major subpopulations reported from photometry could have formed by the same processes that formed halo and disk/bulge globular clusters in the Local Group spiral galaxies. Two globular clusters, which we associate with a group of very red globular clusters, representing about 5% of the total system, clearly stand out and exhibit metal abundances as high as those observed for stellar populations in giant elliptical galaxies. In addition, they display surprisingly high H beta and H gamma indices that are not explained by any age/metallicity combination of existing models. The high Mg and H beta values in these clusters could, however, be explained by the presence of blue horizontal branches. Finally, we find that V-I and metallicity are well correlated in the globular cluster system, but also that the slope of the relation is twice as flat at high metallicities as an extrapolation from the relation for Milky Way globular clusters. This implies that the mean metallicities of globular cluster systems in elliptical galaxies are lower, and cover a smaller range, than ones previously derived from broadband V-I colors. C1 Univ Calif Santa Cruz, UCO Lick Observ, Santa Cruz, CA 95064 USA. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Univ Calif Santa Cruz, UCO Lick Observ, Santa Cruz, CA 95064 USA. EM mkissler@ucolick.org; brodie@ucolick.org; linda@ucolick.org; forbes@star.sr.bham.ac.uk; carl@bb1.jpl.nasa.gov; huchra@fang.harvard.edu NR 61 TC 133 Z9 133 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD JAN PY 1998 VL 115 IS 1 BP 105 EP 120 DI 10.1086/300186 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ454 UT WOS:000071389200010 ER PT J AU Grillmair, CJ Mould, JR Holtzman, JA Worthey, G Ballester, GE Burrows, CJ Clarke, JT Crisp, D Evans, RW Gallagher, JS Griffiths, RE Hester, JJ Hoessel, JG Scowen, PA Stapelfeldt, KR Trauger, JT Watson, AM Westphal, JA AF Grillmair, CJ Mould, JR Holtzman, JA Worthey, G Ballester, GE Burrows, CJ Clarke, JT Crisp, D Evans, RW Gallagher, JS Griffiths, RE Hester, JJ Hoessel, JG Scowen, PA Stapelfeldt, KR Trauger, JT Watson, AM Westphal, JA TI Hubble Space Telescope observations of the Draco dwarf spheroidal galaxy SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, abundances; galaxies, elliptical and lenticular, cD; galaxies, evolution; galaxies, individual (Draco); Local Group ID GLOBULAR-CLUSTERS; RADIAL-VELOCITIES; GALACTIC HALO; URSA-MINOR; STARS; PHOTOMETRY; GIANTS; AGES AB We present an F606W-F814W color-magnitude diagram for the Draco dwarf spheroidal galaxy based on Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC) images. The luminosity function is well sampled to similar to 3 mag below the turnoff. We see no evidence for multiple turnoffs and conclude that, at least over the field of view of the WFPC2, star formation was primarily single-epoch. If the observed number of blue stragglers is due to extended star formation, then roughly 6% (upper limit) of the stars could be half as old as the bulk of the galaxy. The color difference between the red giant branch and the turnoff is consistent with an old population and is very similar to that observed in the old, metal-poor Galactic globular clusters M68 and M92. Despite its red horizontal branch, Draco appears to be older than M68 and M92 by 1.6+/-2.5 Gyr, lending support to the argument that the "second parameter" that governs horizontal-branch morphology must be something other than age, Draco's observed luminosity function is very similar to that of M68, and the derived initial mass function is consistent with that of the solar neighborhood. C1 CALTECH, Dept Astron, Pasadena, CA 91125 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Inst Adv Studies, Weston Creek, ACT 2611, Australia. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Space Telescope Sci Inst, Dept Space Sci, Div Astrophys, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Grillmair, CJ (reprint author), CALTECH, Dept Astron, Mail Stop 105-24, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012; Clarke, John/C-8644-2013 NR 44 TC 71 Z9 71 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 1998 VL 115 IS 1 BP 144 EP 151 DI 10.1086/300169 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ454 UT WOS:000071389200013 ER PT J AU Hasinger, G White, NE AF Hasinger, G White, NE TI X-ray surveys workshop SO ASTRONOMISCHE NACHRICHTEN LA English DT Editorial Material C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hasinger, G (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 3 Z9 3 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 1 EP 2 DI 10.1002/asna.2123190102 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900001 ER PT J AU Newsam, AM McHardy, IM Jones, LR Mason, KO AF Newsam, AM McHardy, IM Jones, LR Mason, KO TI The nature of the faintest X-ray galaxies: near-IR spectroscopy SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch AB We present near-IR spectroscopy of the hydrogen Paschen lines of a sample of X-ray selected Narrow Emission Line Galaxies (NELGs) - the faintest X-ray galaxies. The spectra were obtained in order to distinguish between AGN-like activity, where broad lines would be expected, and starburst activity (narrow lines). We find mostly narrow lines, but we do find some broad Paschen lines. We also see a correlation between the line width and X-ray to optical luminosity ratio, L(X)/L(opt), implying a mixture of starburst and AGN activity in each galaxy with a higher proportion of AGN activity for higher L(X)/L(opt). C1 Univ Southampton, Dept Phys & Astron, Southampton, Hants, England. Univ Birmingham, Sch Phys & Space Res, Birmingham B15 2TT, W Midlands, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Newsam, AM (reprint author), Univ Southampton, Dept Phys & Astron, Southampton, Hants, England. NR 4 TC 0 Z9 0 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 29 EP 29 DI 10.1002/asna.2123190112 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900011 ER PT J AU Miyaji, T Connolly, AJ Szalay, AS Boldt, E AF Miyaji, T Connolly, AJ Szalay, AS Boldt, E TI ROSAT HRI observations of Selected Area 57 SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch ID VARIABILITY; QSOS C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Miyaji, T (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. NR 4 TC 0 Z9 0 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 31 EP 31 DI 10.1002/asna.2123190114 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900013 ER PT J AU Ogasaka, Y Kii, T Ueda, Y Takahashi, T Inoue, H Ishisaki, Y Ohta, K Yamada, T Makishima, K Miyaji, T Hasinger, G AF Ogasaka, Y Kii, T Ueda, Y Takahashi, T Inoue, H Ishisaki, Y Ohta, K Yamada, T Makishima, K Miyaji, T Hasinger, G TI Sky surveys with ASCA - Deep Sky Survey SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch DE cosmic background radiation; X-ray sources ID RAY; VARIABILITY; QSOS AB ASCA Deep Sky Survey (DSS) is aimed to investigate the constituents of the CXB in 2-10 keV band, by faint source survey observations reaching to the source confusion limit of ASCA X-Ray Telescopes. So far, 0.29 deg(2) sky regions were systematically studied and about 40% of the CXB intensity was resolved into discrete sources. In this paper, we present the latest results on the number-flux relation (LogN-LogS) and spectrum properties of faint X-ray sources. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Space & Astronaut Sci, Kanagawa 229, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo 19203, Japan. Kyoto Univ, Dept Astron, Kyoto 60601, Japan. Tohoku Univ, Inst Astron, Sendai, Miyagi 98077, Japan. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. RP Ogasaka, Y (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 14 TC 22 Z9 22 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 43 EP 46 DI 10.1002/asna.2123190122 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900021 ER PT J AU Ueda, Y Takahashi, T Inoue, H Tsuru, T Sakano, M Ohta, K Akiyama, M Ishisaki, Y Ogasaka, Y Makishima, K Yamada, T AF Ueda, Y Takahashi, T Inoue, H Tsuru, T Sakano, M Ohta, K Akiyama, M Ishisaki, Y Ogasaka, Y Makishima, K Yamada, T TI Sky surveys with ASCA - Large Sky Survey SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch DE background radiations; X-rays, general ID RAY AB We have carried out the first systematic wide-area survey around a Galactic pole region with the ASCA satellite in the 0.7-10 keV energy band (Large Sky Survey; LSS). The observed area amounts to 7 deg(2). To make the best use of ASCA capability, we have developed a new source-detection method where the complicated detector responses are fully taken into account. Applying this method to the entire LSS data independently in three energy bands (0.7-2 keV, 2-10 keV, and 0.7-7 keV), we detected 104 sources in total (4.5 sigma detection). The Log N - Log S relation and spectral properties of faint sources are presented. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa, Japan. Kyoto Univ, Dept Phys, Kyoto 60601, Japan. Kyoto Univ, Dept Astron, Kyoto 60601, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo 19203, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tohoku Univ, Inst Astron, Sendai, Miyagi 98077, Japan. RP Ueda, Y (reprint author), Inst Space & Astronaut Sci, Yoshinodai 3-1-1, Kanagawa 229, Japan. NR 14 TC 8 Z9 8 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 47 EP 50 DI 10.1002/asna.2123190123 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900022 ER PT J AU Watanabe, K Leising, MD Hartmann, DH The, LS AF Watanabe, K Leising, MD Hartmann, DH The, LS TI The extragalactic X-ray background due to cosmological supernovae SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch ID IA C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. RP Watanabe, K (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 660-1, Greenbelt, MD 20771 USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 67 EP 67 DI 10.1002/asna.2123190131 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900030 ER PT J AU Ishisaki, Y Ueda, Y Takahashi, T Inoue, H Ogasaka, Y Makishima, K AF Ishisaki, Y Ueda, Y Takahashi, T Inoue, H Ogasaka, Y Makishima, K TI Spectra and large-scale isotropy of the cosmic X-ray background from ASCA observations SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch C1 Tokyo Metropolitan Univ, Dept Phys, Tokyo 19203, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 113, Japan. RP Ishisaki, Y (reprint author), Tokyo Metropolitan Univ, Dept Phys, Tokyo 19203, Japan. NR 6 TC 1 Z9 1 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 68 EP 68 DI 10.1002/asna.2123190132 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900031 ER PT J AU Miyaji, T Ogasaka, Y Boldt, E Connolly, AJ Szalay, AS Koo, DC Kii, T Inoue, H Kunieda, H Tawara, Y AF Miyaji, T Ogasaka, Y Boldt, E Connolly, AJ Szalay, AS Koo, DC Kii, T Inoue, H Kunieda, H Tawara, Y TI The cross-correlation of faint QSOs with the cosmic X-ray background SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. NASA, LHEA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, UCO Lick Observ, Santa Cruz, CA 95064 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Nagoya Univ, Dept Astrophys, Nagoya, Aichi 46401, Japan. RP Miyaji, T (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. NR 4 TC 0 Z9 0 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 69 EP 69 DI 10.1002/asna.2123190133 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900032 ER PT J AU Miyaji, T Ishisaki, Y Ogasaka, Y Ueda, Y Freyberg, MJ Hasinger, G Tanaka, Y AF Miyaji, T Ishisaki, Y Ogasaka, Y Ueda, Y Freyberg, MJ Hasinger, G Tanaka, Y TI The cosmic X-ray background spectrum: an ASCA-ROSAT joint analysis SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Tokyo Metropolitan Univ, Hachioji 19203, Tokyo, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. RP Miyaji, T (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. NR 4 TC 0 Z9 0 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 70 EP 70 DI 10.1002/asna.2123190134 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900033 ER PT J AU Ohta, K Yamada, T Akiyama, M Nakanishi, K Hayashida, K Kii, T Ogasaka, Y AF Ohta, K Yamada, T Akiyama, M Nakanishi, K Hayashida, K Kii, T Ogasaka, Y TI Optical follow-up observations of the ASCA Lynx deep survey SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch ID N-LOG S C1 Kyoto Univ, Dept Astron, Kyoto 60601, Japan. Tohoku Univ, Inst Astron, Sendai, Miyagi 98077, Japan. Osaka Univ, Dept Earth & Space Sci, Osaka 560, Japan. Inst Space & Astronaut Sci, Kanagawa 229, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ohta, K (reprint author), Kyoto Univ, Dept Astron, Kyoto 60601, Japan. NR 8 TC 2 Z9 2 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 71 EP 71 DI 10.1002/asna.2123190135 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900034 ER PT J AU Jones, LR Scharf, C Perlman, E Ebeling, H Horner, D Wegner, G Malkan, M McHardy, I AF Jones, LR Scharf, C Perlman, E Ebeling, H Horner, D Wegner, G Malkan, M McHardy, I TI The X-ray evolution of clusters of galaxies SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch DE X-rays; clusters of galaxies AB The WARPS survey currently contains 48 X-ray selected clusters and groups of galaxies, detected serendipitously in ROSAT PSPC archival pointed observations. The survey includes the highest redshift X-ray selected cluster known (z=0.8325). The redshift range is large enough for evolutionary effects to be studied within the sample. Here we describe the X-ray luminosity function and Log(N)-Log(S) results for the initial complete sample of 29 spectroscopically confirmed clusters. We find that the X-ray luminosity function does not evolve at z-0.5 for cluster luminosities of similar to 10(44) erg s(-1), but that there is a hint of positive evolution at lower luminosities from the number of groups & clusters found in the faintest available X-ray cluster sample (the UK deep survey). C1 Univ Birmingham, Birmingham B15 2TT, W Midlands, England. STScI, Baltimore, MD USA. Univ Hawaii, Honolulu, HI 96822 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Dartmouth Coll, Hanover, NH USA. Univ Calif Los Angeles, Los Angeles, CA USA. Univ Southampton, Southampton, Hants, England. RP Jones, LR (reprint author), Univ Birmingham, Birmingham B15 2TT, W Midlands, England. NR 7 TC 2 Z9 2 U1 1 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 87 EP 90 DI 10.1002/asna.2123190141 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900040 ER PT J AU Chu, YH Snowden, SL AF Chu, YH Snowden, SL TI ROSAT HRI survey of the Large Magellanic Cloud SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch DE Large Magellanic Cloud; X-ray binaries; interstellar medium; supernova remnants; diffuse emission ID X-RAY SOURCES AB We have started a ROSAT HRI survey of the Large Magellanic Cloud (LMC). The current scope of the survey is to map the 30 Doradus region and the bar of the LMC with at least 20 ksec exposure at each position. The survey grid has a 15' separation between adjacent pointings. The survey has been awarded a total of 39 priority B pointings in AO5-7. The HRI survey of the LMC will provide X-ray luminosity functions of point sources complete down to similar to 1 x 10(34) erg s(-1). In addition, the survey images have resolved small diffuse sources, such as the SNR 0534-69.9 and the superbubble 30 Dor C, and detected diffuse emission on large scales. An HRI mosaic of the LMC is presented and compared to an H alpha image. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chu, YH (reprint author), Univ Illinois, Dept Astron, 1002 W Green St, Urbana, IL 61801 USA. RI Snowden, Steven/D-5292-2012 NR 15 TC 7 Z9 7 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 101 EP 104 DI 10.1002/asna.2123190146 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900045 ER PT J AU Jahoda, K AF Jahoda, K TI Present Epoch Plus - an X-ray survey for cosmology SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch DE space mission; hard X-rays; cosmology ID DIPOLE; HEAO-1; BURSTS; FRAME AB This paper summarizes some cosmologically interesting measurements which are uniquely possible in the hard X-ray band and presents a mission concept capable of achieving them. The Present Epoch Plus mission will achieve a surface brightness sensitivity of better than 1% per square degree in the 2-10 keV band, and create a catalog of similar to 10(6) sources. About 160,000 extragalactic sources are expected to be detected in the 2-10 keV band, providing an all sky survey with nearly uniform selection effects 10 times deeper than exisiting or planned surveys. The PEP concept can be achieved within the size and budgetary constraints of a NASA Medium Explorer (MIDEX) mission. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jahoda, K (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. RI Jahoda, Keith/D-5616-2012 NR 17 TC 4 Z9 4 U1 0 U2 0 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 129 EP 132 DI 10.1002/asna.2123190159 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900058 ER PT J AU Sanders, WT Boldt, EA Brickhouse, NS Cox, DP Edgar, RJ Jahoda, K Kallman, T Kelley, RL Liedahl, DA McCammon, D Mushotzky, RF Paulos, RJ Porter, FS Raymond, JC Shelton, RL Smith, RK Snowden, SL Stahle, CK Szymkowiak, AE White, NE AF Sanders, WT Boldt, EA Brickhouse, NS Cox, DP Edgar, RJ Jahoda, K Kallman, T Kelley, RL Liedahl, DA McCammon, D Mushotzky, RF Paulos, RJ Porter, FS Raymond, JC Shelton, RL Smith, RK Snowden, SL Stahle, CK Szymkowiak, AE White, NE TI XBSS - The X-ray Background Spectroscopic Survey SO ASTRONOMISCHE NACHRICHTEN LA English DT Article; Proceedings Paper CT X-ray Surveys Workshop - To Mark the Occasion of the 35th Anniversary of the Birth of X-Ray Astronomy and the 7th Anniversary of the First Light of ROSAT CY JUN 18-20, 1997 CL POTSDAM, GERMANY SP Astrophysikal Inst Potsdam, NASA Goddard Space Flight Ctr X-Ray Astrophys Branch C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sanders, WT (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. RI White, Nicholas/B-6428-2012; Porter, Frederick/D-3501-2012; Snowden, Steven/D-5292-2012; Jahoda, Keith/D-5616-2012; Kelley, Richard/K-4474-2012 OI White, Nicholas/0000-0003-3853-3462; Porter, Frederick/0000-0002-6374-1119; NR 0 TC 0 Z9 0 U1 1 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0004-6337 J9 ASTRON NACHR JI Astro. Nachr. PY 1998 VL 319 IS 1-2 BP 151 EP 151 DI 10.1002/asna.2123190167 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YY346 UT WOS:000072137900066 ER PT J AU Pardo, JR Cernicharo, J Gonzalez-Alfonso, E Bujarrabal, V AF Pardo, JR Cernicharo, J Gonzalez-Alfonso, E Bujarrabal, V TI Simultaneous observations of maser lines of (SiO)-Si-28 in evolved stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : AGB, post-AGB; masers; stars : circumstellar matter; radio-lines : stars ID VY CANIS MAJORIS; NUMERICAL-CALCULATIONS; SIO MASERS; EMISSION; TRANSITION AB We present simultaneous observations of several rotational lines of (SiO)-Si-28 in the v = 1, 2, 3, and 4 vibrationally excited states toward O-rich evolved stars. All the data were taken in a relatively short period of 65 days, which allows a comparative study of the (SiO)-Si-28 maser lines intensities and profiles. The observed differences concerning intensity and line shape among the different maser lines suggest that infrared overlaps deeply affect the pumping of some SiO masers. We qualitatively discuss this effect with consideration to the IR overlaps at 8 mu m between the various SiO isotopomers and between (SiO)-Si-28 and water vapor(1). C1 Observ Astron Nacl, E-28800 Alcala De Henares, Madrid, Spain. Observ Paris, DEMIRM, F-75014 Paris, France. CSIC, Inst Estructura Mat, Dept Fis Mol, E-28006 Madrid, Spain. Univ Alcala de Henares, Dept Fis, E-28871 Alcala De Henares, Madrid, Spain. RP Pardo, JR (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 26 TC 19 Z9 19 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 JAN 1 PY 1998 VL 329 IS 1 BP 219 EP 228 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YM587 UT WOS:000071079700030 ER PT J AU Young, PR Landi, E Thomas, RJ AF Young, PR Landi, E Thomas, RJ TI CHIANTI: an atomic database for emission lines - II. Comparison with the SERTS-89 active region spectrum SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE atomic data; astronomical databases : miscellaneous; Sun : UV radiation ID EUV-ROCKET-TELESCOPE; ELECTRON-IMPACT EXCITATION; FE-XIV; COLLISION STRENGTHS; SPECTROGRAPH SERTS; SOLAR IDENTIFICATIONS; OSCILLATOR-STRENGTHS; PROTON EXCITATION; INTENSITIES; TRANSITIONS AB The CHIANTI database was described by Dere et al. (1997, hereafter Paper I) and the present paper applies the atomic data to the study of extreme ultra-violet emission lines found in the SERTS-89 active region spectrum published by Thomas & Neupert (1994). Firstly, the emission line ratios that are insensitive to density and temperature are used to check both the quality of the atomic data and the calibration of the instrument. Secondly, we use, where possible, ratios that are sensitive to density to estimate the electron density from different ions. In general we find excellent agreement between theory and observation, providing confidence in both the atomic data in the CHIANTI database and the quality of the SERTS-89 spectrum. Where inconsistencies between theory and observation exist we try to explain them in terms of either inaccuracies in the atomic data or blending of the lines. One consistent discrepancy was that all observed lines that we analysed in the 430-450 Angstrom region were uniformly a factor of 1.5-2.0 weaker than predicted, suggesting that the SERTS-89 calibration may need adjustment in this spectral interval. Serious problems were also found in some of the theoretical predictions for a few ions, especially Fe XIV. C1 Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB2 1TN, England. Univ Florence, Dept Astron & Space Sci, I-50125 Florence, Italy. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Young, PR (reprint author), Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB2 1TN, England. RI Landi, Enrico/H-4493-2011 NR 44 TC 108 Z9 108 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN 1 PY 1998 VL 329 IS 1 BP 291 EP 314 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YM587 UT WOS:000071079700037 ER PT J AU Harris, MJ Murphy, RJ Share, GH Johnson, WN Kinzer, RL Kurfess, JD McNaron-Brown, K Purcell, WR AF Harris, MJ Murphy, RJ Share, GH Johnson, WN Kinzer, RL Kurfess, JD McNaron-Brown, K Purcell, WR TI OSSE observations of the Orion giant molecular cloud during 1996 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : individual objects : Orion clouds; cosmic rays; gamma-rays : observations ID GAMMA-RAY LINES; COMPLEX; SPECTROSCOPY; MONOCEROS AB We have combined all OSSE spectra of the Orion molecular cloud complex obtained through the end of 1996 and searched them for evidence of cosmic-ray induced gamma-ray lines in the 3-7 MeV energy range, as detected by COMPTEL (Bloemen et al. 1994, 1997). We do not detect any significant line emission; our flux estimate for broad-line emission of 1.5 +/- 1.0 10(-4) gamma/(cm(2)-s) is consistent with the spatially-extended flux 1.3 10(-4) gamma/(cm(2)-s) measured by Bloemen et al. (1997). C1 NASA, USRA, GVSP, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. George Mason Univ, Phys CSI, Fairfax, VA 22030 USA. Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. RP Harris, MJ (reprint author), NASA, USRA, GVSP, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Johnson, Neil/G-3309-2014 NR 15 TC 5 Z9 5 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 1998 VL 329 IS 2 BP 624 EP 630 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ939 UT WOS:000071439900026 ER PT J AU Buckley, JH Akerlof, CW Carter-Lewis, DA Catanese, M Cawley, MF Connaughton, V Fegan, DJ Finley, JP Gaidos, JA Hillas, AM Krennrich, F Lamb, RC Lessard, RW McEnery, JE Mohanty, G Quinn, J Rodgers, AJ Rose, HJ Rovero, AC Schubnell, MS Sembroski, G Srinivasan, R Weekes, TC Zweerink, J AF Buckley, JH Akerlof, CW Carter-Lewis, DA Catanese, M Cawley, MF Connaughton, V Fegan, DJ Finley, JP Gaidos, JA Hillas, AM Krennrich, F Lamb, RC Lessard, RW McEnery, JE Mohanty, G Quinn, J Rodgers, AJ Rose, HJ Rovero, AC Schubnell, MS Sembroski, G Srinivasan, R Weekes, TC Zweerink, J TI Constraints on cosmic-ray origin from TeV gamma-ray observations of supernova remnants SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE gamma-rays : observations; SNRs; cosmic rays; ISM : IC 443, gamma Cyg SNR, W 44 ID 11 CM WAVELENGTH; PARTICLE-ACCELERATION; SHOCK ACCELERATION; X-RAY; MOLECULAR CLOUDS; NOVA REMNANT; ELECTRON ACCELERATION; GALACTIC PLANE; ENERGY-SPECTRA; TYCHO AB If supernova remnants (SNRs) are the site of cosmic-ray acceleration, the associated nuclear interactions should result in an observable flux of gamma-rays for the nearest SNRs. Measurements of the TeV gamma-ray flux from six nearby, radio-bright SNRs have been made with the Whipple Observatory imaging air Cerenkov telescope over the period September 1993 to June 1996. No significant emission has been detected and upper limits on the >300 GeV flux are reported. Three of these SNRs (IC443, gamma-Cygni and W44) are spatially coincident with low-latitude otherwise unidentified sources detected with the Energetic Gamma-Ray Experiment Telescope (EGRET). If the EGRET gamma-ray fluxes result from cosmic-ray interactions then the EGRET and Whipple data are found to be collectively inconsistent with a cosmic-ray source spectrum flatter than similar to E-2.4. The Whipple upper limits for IC443 and gamma-Cygni are also inconsistent with a priori predictions if these remnants are indeed expanding into regions where the average density of the interstellar medium is enhanced by the presence of molecular clouds. These data weaken the case for the simplest models of shock acceleration and energy dependent propagation of cosmic rays. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. St Patricks Coll, Dept Phys, Maynooth, Kildare, Ireland. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Natl Univ Ireland Univ Coll Dublin, Dept Phys, Dublin 4, Ireland. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Whipple Observ, Amado, AZ 85645 USA. Inst Astron & Fis Espacio, RA-1428 Buenos Aires, DF, Argentina. RP Buckley, JH (reprint author), Washington Univ, Dept Phys, St Louis, MO 63130 USA. NR 119 TC 117 Z9 117 U1 0 U2 2 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 JAN PY 1998 VL 329 IS 2 BP 639 EP 658 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ939 UT WOS:000071439900028 ER PT J AU Lecacheux, A Boudjada, MY Rucker, HO Bougeret, JL Manning, R Kaiser, ML AF Lecacheux, A Boudjada, MY Rucker, HO Bougeret, JL Manning, R Kaiser, ML TI Jovian decameter emissions observed by the Wind/WAVES radioastronomy experiment SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE planets and satellites : Jupiter; radio continuum : solar system ID COMPLETE POLARIZATION STATE; IO FLUX TUBE; RADIO-EMISSION; JUPITER; RADIATION; VOYAGER; ARCS; SPECTRA; STORMS; EARTH AB The WAVES radio astronomy experiment aboard the Wind spacecraft covers the frequency range from 1 MHz to 13.8 MHz with spectral resolution six times better than that of the Voyager PRA experiment. By combining Wind/WAVES observations with simultaneous observations made by the Nancay Decametric Array (France) between 10 and 40 MHz, the entire frequency spectrum of the jovian decametric emission can be observed. Two representative Io-controlled events (Io-B/D and Io-C) have been selected and analysed in terms of the available models of the jovian environment. In the case of the Io-B/D event at frequencies below 20 MHz, observations and models, to some extent, may fit an emission beam aperture of about 87 degrees. To explain the higher frequencies we must assume that small refraction effects take place near the source region, consistent with topside jovian ionospheric parameters deduced from previous direct measurements. The Io-C event cannot be explained with this simple emission beam geometry: additional effects have to be invoked, as strong propagation effects near caustics or large distortion of the magnetic field in the source. C1 Observ Paris, ARPEGES, CNRS, URA 1757, F-92195 Meudon, France. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. Observ Paris, DESPA, CNRS, URA 264, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lecacheux, A (reprint author), Observ Paris, ARPEGES, CNRS, URA 1757, F-92195 Meudon, France. RI Boudjada, Mohammed/G-4737-2012 NR 37 TC 23 Z9 23 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 1998 VL 329 IS 2 BP 776 EP 784 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ939 UT WOS:000071439900040 ER PT J AU Leinert, C Bowyer, S Haikala, LK Hanner, MS Hauser, MG Levasseur-Regourd, AC Mann, I Mattila, K Reach, WT Schlosser, W Staude, HJ Toller, GN Weiland, JL Weinberg, JL Witt, AN AF Leinert, C Bowyer, S Haikala, LK Hanner, MS Hauser, MG Levasseur-Regourd, AC Mann, I Mattila, K Reach, WT Schlosser, W Staude, HJ Toller, GN Weiland, JL Weinberg, JL Witt, AN TI The 1997 reference of diffuse night sky brightness SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Review DE diffuse radiation; interplanetary medium; atmospheric effects; astronomical databases, miscellaneous; infrared, general; ultraviolet, general ID EXTENDED RED EMISSION; ULTRAVIOLET BACKGROUND-RADIATION; VISUAL REFLECTION NEBULAE; HIGH GALACTIC LATITUDE; COBE FIRAS INSTRUMENT; ZODIACAL DUST CLOUD; SOURCE INFRARED SKY; FAR-ULTRAVIOLET; CIRCUMSOLAR DUST; INTERPLANETARY DUST AB In the following we I?resent material in tabular and graphical form, with the aim to allow the non-specialist to obtain a realistic estimate of the diffuse night sky brightness over a wide range of wavelengths from the far UV longward of Ly alpha to the far-infrared. At the same time the data are to provide a reference for cases in which background brightness has to be discussed; including the planning for space observations and the issue of protection of observatory sites. We try to give a critical presentation of the status at the beginning of 1997. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Helsinki, Observ, FIN-00014 Helsinki, Finland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Ruhr Univ Bochum, Inst Astron, D-44780 Bochum, Germany. Gen Sci Corp, Laurel, MD 20707 USA. NASA, Hughes STX, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MK Ind, Tucker, GA 30084 USA. Univ Toledo, Ritter Astrophys Res Ctr, Toledo, OH 43606 USA. RP Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. RI Reach, William/C-4710-2008; OI Reach, William/0000-0001-8362-4094; Haikala, Lauri Kristian/0000-0001-9279-2815 NR 334 TC 230 Z9 233 U1 1 U2 4 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 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD JAN PY 1998 VL 127 IS 1 BP 1 EP 99 PG 99 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ928 UT WOS:000071438700001 ER PT J AU Kashlinsky, A AF Kashlinsky, A TI Reconstructing the spectrum of the pregalactic density field from astronomical data SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmology, dark matter; cosmology, theory; galaxies, formation; large-scale structure of universe ID COLD DARK MATTER; LARGE-SCALE STRUCTURE; CLUSTER CORRELATION-FUNCTION; APM GALAXY SURVEY; POWER SPECTRUM; HIGH-REDSHIFT; COSMOLOGICAL CONSTANT; ELLIPTICAL GALAXIES; RADIO GALAXY; VELOCITY CORRELATIONS AB In this paper we evaluate the spectrum of the pregalactic density field on scales 1 h(-1) Mpc < r < 100 h(-1) Mpc from a variety of astronomical data. We start with the APM data on the projected angular correlation function, w(theta), in six narrow magnitude bins and check whether possible evolutionary effects can affect inversion of the w(theta) data in terms of the underlying power spectrum. This is done by normalizing to the angular correlation function on small scales where the underlying three-dimensional galaxy correlation function, xi(r) is known. Using the Automatic Plate Measuring Facility (APM) data in narrow magnitude bins allows us to test the various fits to the APM data power spectrum more accurately. We find that for linear scales r > 10 h(-1) Mpc, the Baugh & Efstathiou spectrum of galaxy distribution gives the best fit to the data at all depths. Fitting power spectra of cold dark matter (CDM) models to the data at all depths requires Omega h = 0.2 if the primordial index n = 1 and Omega h = 0.3 if the spectrum is tilted with n = 0.7. Next we compare the peculiar velocity field predicted by the APM spectrum of galaxy (light) distribution with the actual velocity data. The two fields are consistent, and the comparison suggests that the bias factor is scale independent with Omega(0.6)/b similar or equal to (0.2-0.4). These steps enable us to fix the pregalactic mass-density field on scales between 10 and similar to 100 h(-1) Mpc. The next data set we use to determine the pregalactic density field comes from the cluster correlation data. We calculate in detail the amplification of the cluster correlation function due to gravitational clustering and use the data on both the slope of the cluster correlation function and its amplitude-richness dependence. Cluster masses are normalized using the Coma Cluster. We find that no CDM model can fit all three data sets: APM data on w(8), the data on cluster correlation function, and the data on the latter's amplitude-richness dependence. Next we show that the data on the amplitude-richness dependence can be used directly to obtain the spectrum of the pregalactic density field. Applying the method to the data, we recover the density field on scales between 5 and 25 h(-1) Mpc whose slope is in good agreement with the APM data on the same scales. Requiring the two amplitudes to coincide fixes the value of Omega to be 0.25-0.3 in agreement with observations of the dynamics of the Coma Cluster. We then use the data on high-z objects to constrain the small-part, (1-5) h(-1) Mpc of the pregalactic density field. We argue that the data at high redshifts require more power than given by CDM models normalized to the APM and cluster data. Then we reconstruct the pregalactic density field out of which modern-day galaxies have formed. We use the data on blue absolute luminosities, the fundamental plane relations, and the latest X-ray data on the halo velocity dispersion. From this we recover the pregalactic density field on comoving scales between 1 and 5 h(-1) Mpc, which is in reasonable agreement with the simple power-law extrapolation from the larger scales. C1 NASA, Goddard Space Flight Ctr, Code 685, Hughes STX, Greenbelt, MD 20771 USA. NORDITA, DK-2100 Copenhagen O, Denmark. Theoret Astrophys Ctr, DK-2100 Copenhagen O, Denmark. RP Kashlinsky, A (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Hughes STX, Greenbelt, MD 20771 USA. EM kashlinsky@stars.gsfc.nasa.gov NR 134 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP 1 EP 28 DI 10.1086/305027 PN 1 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ455 UT WOS:000071389300001 ER PT J AU Madore, BF Freedman, WL AF Madore, BF Freedman, WL TI Hipparcos parallaxes and the cepheid distance scale SO ASTROPHYSICAL JOURNAL LA English DT Article DE Cepheids; galaxies, distances and redshifts; Magellanic Clouds AB Hipparcos parallaxes have recently become available for a sample of Galactic Cepheids, and we have used these new distances to calibrate the Cepheid period-luminosity (PL) relation at six wavelengths (BVIJHK). Comparing these calibrations with previously published multiwavelength PL relations pie find agreement to within 0.07 +/- 0.14 mag, or 4% +/- 7% in distance. Unfortunately, the current parallax errors for the fundamental pulsators (ranging in signal-to-noise ratio = pi/sigma(pi) from 0.3 to 5.3, at best) preclude an unambiguous interpretation of the observed differences. which may arise from a combination of true distance modulus, reddening, and/or metallicity effects. We explore these effects and discuss their implications for the distance to the Large Magellanic Cloud (LMC) and the Cepheid-based extragalactic distance scale. These results suggest a range of LMC moduli between 18.44 +/- 0.35 and 18.57 +/- 0.11 mag; however, other effects on the Cepheid PL relation (e.g., extinction, metallicity, and statistical errors) are still as significant as any such reassessment of its zero point. C1 CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. RP Madore, BF (reprint author), CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. NR 22 TC 87 Z9 88 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP 110 EP 115 DI 10.1086/305041 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ455 UT WOS:000071389300011 ER PT J AU Surace, JA Sanders, DB Vacca, WD Veilleux, S Mazzarella, JM AF Surace, JA Sanders, DB Vacca, WD Veilleux, S Mazzarella, JM TI HST/WFPC2 observations of warm ultraluminous infrared galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, interactions; galaxies, starburst; galaxies, star clusters; infrared, galaxies ID HUBBLE-SPACE-TELESCOPE; BRIGHT QUASAR SURVEY; STAR-CLUSTERS; SURFACE PHOTOMETRY; GLOBULAR-CLUSTERS; PERFORMANCE; CALIBRATION; EVOLUTION; NUCLEUS; WFPC2 AB We present new high-resolution B-and I-band images of a nearly complete sample of nine "warm" (f(25)/f(60) > 0.2), ultraluminous infrared galaxies (ULIGs) obtained with the Wide Field Planetary Camera of the Hubble Space Telescope (HST). The HST images clearly reveal the presence of tidal tails and other features associated with merging galaxies. All of the warm ULIGs show evidence of complex structures such as dust lanes and spiral features in their inner few kiloparsecs. Additionally, they show compact, blue "knots" of star formation (between 4 and 31 knots per object) that appear similar to those seen in more nearby merger systems. Spectral synthesis modeling is used to estimate mean upper age limits and masses: the median upper age limit for the knots in individual galaxies is similar to 3 x 10(8) yr (ranging from similar to 10(7) to 1 x 10(9) yr), and the range of knot masses is similar to 10(5)-10(9) M.. We also argue that these starburst knots cannot be significant contributors to the extremely high bolometric luminosity of these galaxies. Additionally, each object contains one or two knots whose luminosity and color are implausible in terms of star formation; we identify these as putative active nuclei. These observations are consistent with the hypothesis that warm ULIGs may represent a critical transition stage in the evolution of ULIGs into optical quasi-stellar objects. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. RP Surace, JA (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. NR 53 TC 181 Z9 181 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP 116 EP + DI 10.1086/305028 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ455 UT WOS:000071389300012 ER PT J AU Kippen, RM Ryan, JM Connors, A Hartmann, DH Winkler, C Kuiper, L Varendorff, M McConnell, ML Hurley, K Hermsen, W Schonfelder, V AF Kippen, RM Ryan, JM Connors, A Hartmann, DH Winkler, C Kuiper, L Varendorff, M McConnell, ML Hurley, K Hermsen, W Schonfelder, V TI The locations of gamma-ray bursts measured by COMPTEL SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts; gamma rays, observations; methods, numerical; methods, statistical ID RAPID RESPONSE NETWORK; X-RAY; OORT CLOUD; BATSE; CATALOG; ORIGIN; GALAXIES; REPEATER; OBJECTS AB The COMPTEL instrument on the Compton Gamma Ray Observatory is used to measure the locations of gamma-ray bursts through direct imaging of MeV photons. In a comprehensive search, we have detected and localized 29 bursts observed between 1991 April 19 and 1995 May 31. The average location accuracy of these events is 1.degrees 25 (1 sigma), including a systematic error of similar to 0.degrees 5, which is verified through comparison with Interplanetary Network (IPN) timing annuli. The combination of COMPTEL and IPN measurements results in locations for 26 of the bursts with an average "error box" area of only similar to 0.3 deg(2) (1 sigma). We find that the angular distribution of COMPTEL burst locations is consistent with large-scale isotropy and that there is no statistically significant evidence of small-angle autocorrelations. We conclude that there is no compelling evidence for burst repetition since no more than two of the events (Or similar to 7% of the 29 bursts) could possibly have come from the same source. We also find that there is no significant correlation between the bust locations and either Abell clusters of galaxies or radio-quiet quasars. Agreement between individual COMPTEL locations and IPN annuli places a lower limit of similar to 100 AU (95% confidence) on the distance to the stronger bursts. C1 Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. European Space Agcy, European Space Res & Technol Ctr, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. SRON, NL-3584 Utrecht, Netherlands. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Kippen, RM (reprint author), NASA, George C Marshall Space Flight Ctr, ES-84, Huntsville, AL 35812 USA. NR 92 TC 13 Z9 13 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP 246 EP 262 DI 10.1086/305033 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ455 UT WOS:000071389300022 ER PT J AU Broderick, JJ Herrin, ET Krisher, TP Morgan, DL Rosenbaum, DC Sher, M Teplitz, VL AF Broderick, JJ Herrin, ET Krisher, TP Morgan, DL Rosenbaum, DC Sher, M Teplitz, VL TI Millimeter-wave signature of strange matter stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE elementary particles; pulsars, general; stars, neutron; stars, oscillations ID PULSAR AB One of the most important questions in the study of compact objects is the nature of pulsars, including whether they consist of neutron star matter or strange quark matter (SQM). However, few mechanisms for distinguishing between these two possibilities have been proposed. The purpose of this Letter is to show that a strange star (one made of SQM) will have a vibratory mode with an oscillation frequency of approximately 250 GHz (millimeter wave). This mode corresponds to motion of the center of the expected crust of normal matter relative to the center of the strange quark core, without distortion of either. Radiation from currents generated in the crust at the mode frequency would be an SQM signature. We also consider effects of stellar rotation, estimate power emission and signal-to-noise ratio, and discuss briefly the particularly important, but unsolved, question of possible mechanisms for exciting the mode. C1 Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. So Methodist Univ, Dept Phys, Dallas, TX 75275 USA. RP Broderick, JJ (reprint author), Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. NR 16 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP L71 EP L74 DI 10.1086/311078 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ456 UT WOS:000071389400018 ER PT J AU Cui, W Zhang, SN Chen, W AF Cui, W Zhang, SN Chen, W TI Evidence for frame-dragging around spinning black holes in X-ray binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; X-rays, stars ID ACCRETION DISKS; EXTRACTION; OUTFLOWS; ENERGY; FLOWS; STARS; JETS AB In the context of black hole spin in X-ray binaries, we propose that certain types of quasi-periodic oscillations (QPOs) observed in the light curves of black hole binaries (BHBs) are produced by X-ray modulation at the precession frequency of accretion disks, because of relativistic dragging of inertial frames around spinning black holes. These QPOs tend to be relatively stable in their centroid frequencies. They have been observed in the frequency range of a few hertz to a few hundred hertz for several black holes with dynamically determined masses. By comparing the computed disk precession frequency with that of the observed QPO, we can derive the black hole spin, given its mass. When applying this model to GRO J1655-40, GRS 1915+105, Cyg X-l, and GS 1124-68, we found that the black holes in GRO J1655-40 and GRS 1915+105, the only known BHBs that occasionally produce superluminal radio jets, spin at a rate close to the maximum limit, while Cyg X-l and GS 1124-68, typical (persistent and transient) BHBs, contain only moderately rotating ones. Extending the model to the general population of black hole candidates, the fact that only low-frequency QPOs have been detected is consistent with the presence of only slowly spinning black holes in these systems. Our results are in good agreement with those derived from spectral data, thus strongly supporting the classification scheme that we proposed previously for BHBs. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cui, W (reprint author), MIT, Ctr Space Res, Cambridge, MA 02139 USA. NR 33 TC 64 Z9 67 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP L53 EP L57 DI 10.1086/311092 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ456 UT WOS:000071389400014 ER PT J AU Pian, E Vacanti, G Tagliaferri, G Ghisellini, G Maraschi, L Treves, A Urry, CM Fiore, F Giommi, P Palazzi, E Chiappetti, L Sambruna, RM AF Pian, E Vacanti, G Tagliaferri, G Ghisellini, G Maraschi, L Treves, A Urry, CM Fiore, F Giommi, P Palazzi, E Chiappetti, L Sambruna, RM TI BeppoSAX observations of unprecedented synchrotron activity in the BL Lacertae object Markarian 501 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects, individual (Markarian 501); galaxies, active; galaxies, nuclei; radiation mechanisms, nonthermal; X-rays, galaxies ID EXTRAGALACTIC RADIO-SOURCES; X-RAY-SPECTRA; BLAZARS; GALAXIES; QUASARS; FLUX AB The BL Lacertae object Markarian 501, one of only three extragalactic sources (with Mrk 421 and IES 2344+514) so far detected at TeV energies, was observed with the BeppoSAX satellite in 1997 April 7, 11, and 16 during a phase of high activity at TeV energies, as monitored with the Whipple, HEGRA, and CAT Cherenkov telescopes. Over the whale 0.1-200 keV range, the spectrum was exceptionally hard (alpha less than or equal to 1, with F-v proportional to nu(-alpha)), indicating that the X-ray power output peaked at (or above) similar to 100 keV. This represents a shift of at least 2 orders of magnitude with respect to previous observations of Mrk 501, a behavior never seen before in this or any other blazar. The overall X-ray spectrum hardens with increasing intensity, and at each epoch it is softer at larger energies. The correlated variability from soft X-rays to the TeV band points to models in which the same population of relativistic electrons produces the X-ray continuum via synchrotron radiation and the TeV emission by inverse Compton scattering of the synchrotron photons or other seed photons. For the first lime in any blazar, the synchrotron power is observed to peak at hard X-ray energies. The large shift of the synchrotron peak frequency with respect to previous observations of Mrk 501 implies that intrinsic changes in the relativistic electron spectrum caused the increase in emitted power. Due to the very high electron energies, the inverse Compton process is limited by the Klein-Nishina regime. This implies a quasi-linear (as opposed to quadratic) relation of the variability amplitude in the TeV and hard X-ray ranges (for the synchrotron self-Compton model) and an increase of the inverse Compton peak frequency smaller than that of the synchrotron peak frequency. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. CNR, Ist Tecnol & Studio Radiaz Extraterr, I-40129 Bologna, Italy. European Space Agcy, Estec, Dept Space Sci, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Osservatorio Astron Brera, I-22055 Lecce, Italy. Osservatorio Astron Brera, I-20121 Milan, Italy. Univ Milan, Dept Phys, I-22100 Como, Italy. SAX SDC, I-00131 Rome, Italy. CNR, Ist Fis Cosm, I-20133 Milan, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pian, E (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Urry, Claudia/G-7381-2011; Palazzi, Eliana/N-4746-2015; OI Urry, Claudia/0000-0002-0745-9792; Chiappetti, Lucio/0000-0001-7857-7908; Ghisellini, Gabriele/0000-0002-0037-1974; Palazzi, Eliana/0000-0002-8691-7666; Fiore, Fabrizio/0000-0002-4031-4157 NR 32 TC 146 Z9 146 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP L17 EP L20 DI 10.1086/311083 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ456 UT WOS:000071389400005 ER PT J AU Rubin, BC Harmon, BA Paciesas, WS Robinson, CR Zhang, SN Fishman, GJ AF Rubin, BC Harmon, BA Paciesas, WS Robinson, CR Zhang, SN Fishman, GJ TI A sequence of declining outbursts from GX 339-4 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, general; black hole physics; stars, individual (GX 339-4); X-rays, stars ID X-RAY; GX-339-4; GX339-4 AB The flux and spectrum of the black hole candidate GX 339-4 has been monitored by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory since the observatory became operational in 1991 May. Between the summer of 1991 and the fall of 1996, eight outbursts from GX 339-4 were observed. The history of these outbursts is one of declining fluence or total energy release, as well as a shortening of the time between outbursts. A rough linear correlation exists between the fluence emitted during an outburst and the time elapsed between the end of the previous outburst and the beginning of the current one. The peak flux is also roughly linearly correlated with outburst fluence. The light curves of the earlier, more intense, outbursts (except for the second one) can be modeled by a fast exponential (time constant similar to 10 days) followed by a slower exponential (similar to 100 days) on the rise and a fast exponential decay (similar to 5 days) on the fall. The later, weaker, outbursts are modeled with a single, rising time constant (similar to 20 days) and a longer decay on the fall (similar to 50 days). An exponential model gives a marginally better fit than a power law to the rise/decay profiles. GX 339-4 is a unique source in having more frequent outbursts than other low-mass X-ray binary black hole candidates. These observations can be used to constrain models of the behavior of the accretion disk surrounding the compact object. C1 RIKEN, Inst Phys & Chem Res, Cosm Radiat Lab, Wako, Saitama 35101, Japan. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Rubin, BC (reprint author), RIKEN, Inst Phys & Chem Res, Cosm Radiat Lab, Wako, Saitama 35101, Japan. NR 16 TC 16 Z9 16 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1998 VL 492 IS 1 BP L67 EP L70 DI 10.1086/311079 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YQ456 UT WOS:000071389400017 ER PT J AU Gorski, KM Ratra, B Stompor, R Sugiyama, N Banday, AJ AF Gorski, KM Ratra, B Stompor, R Sugiyama, N Banday, AJ TI COBE-DMR-normalized open cold dark matter cosmogonies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE cosmic microwave background; cosmology, observations; galaxies, formation; large-scale structure of universe ID BIG-BANG NUCLEOSYNTHESIS; MICROWAVE BACKGROUND-RADIATION; HUBBLE-SPACE-TELESCOPE; 1ST-ORDER PHASE-TRANSITION; HIGH DEUTERIUM ABUNDANCE; STAR-FORMING GALAXIES; OPEN UNIVERSE; OPEN INFLATION; POWER SPECTRUM; HIGH-REDSHIFT AB Cut-sky orthogonal mode analyses of the COBE-DMR 53 and 90 GHz sky maps are used to determine the normalization of a variety of open cosmogonical models based on the cold dark matter scenario. To constrain the allowed cosmological parameter range for these open cosmogonies, the predictions of the DMR-normalized models are compared to various observational measures of cosmography and large-scale structure, viz., the age of the universe; small-scale dynamical estimates of the clustered-mass density parameter Omega(0); constraints on the Hubble parameter h, the X-ray cluster baryonic-mass fraction Omega(B)/Omega(0), and the matter power spectrum shape parameter; estimates of the mass perturbation amplitude; and constraints on the large-scale peculiar velocity held. The open-bubble inflation model (Ratra & Peebles; Bucher, Goldhaber, & Turok; Yamamoto, Sasaki, & Tanaka) is consistent with current determinations of the 95% confidence level (c.l.) range of these observational constraints, provided 0.3 < Omega(0) less than or similar to 0.6 (similar to 95% c.l.). More specifically, for a range of h, the model is reasonably consistent with recent high-redshift estimates of the deuterium abundance that suggest Omega(B)h(2) similar to 0.007, provided Omega(0) similar to 0.35; recent high-redshift estimates of the deuterium abundance that suggest Omega(B)h(2) similar to 0.02 favor Omega(0) similar to 0.5, while the old nucleosynthesis value Omega(B)h(2) = 0.0125 requires Omega(0) similar to 0.4. Small shifts in the inferred COBE-DMR normalization amplitudes due to (1) the small differences between the galactic-and ecliptic-coordinate sky maps, (2) the inclusion or exclusion of the quadrupole moment in the analysis, (3) the faint high-latitude Galactic emission treatment, and (4) the dependence of the theoretical cosmic microwave background anisotropy angular spectral shape on the value of h and Omega(B), are explicitly quantified. Corresponding variations in the likelihood fits of models to the DMR data then imply that the DMR data alone do not possess sufficient discriminative power to prefer any values for Omega(0), h, or Omega(B), at the 95% c.l. for the models considered. At a lower c.l., and when the quadrupole moment is included in the analysis, the DMR data are most consistent with either Omega(0) less than or similar to 0.1 or Omega(0) similar to 0.7 (depending on the model considered). However, when the quadrupole moment is excluded from the analysis, the DMR data are most consistent with Omega(0) similar to 0.35-0.5 in all open models considered (with 0.1 less than or equal to Omega(0) less than or equal to, 1), including the open-bubble inflation model. Earlier claims (Yamamoto & Bunn; Bunn & White) that the DMR data require a 95% c.l. lower bound on Omega(0) (similar to 0.3) are not supported by our (complete) analysis of the 4 year data: the DMR data alone cannot be used to constrain Omega(0) meaningfully. C1 NASA, Goddard Space Flight Ctr, Hughes STX Corp, LASP, Greenbelt, MD 20771 USA. Theoret Astrophys Ctr, Copenhagen 2100, Denmark. Univ Warsaw Observ, PL-00478 Warsaw, Poland. MIT, Ctr Theoret Phys, Cambridge, MA 02139 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Kyoto Univ, Dept Phys, Sakyo Ku, Kyoto 606, Japan. Max Planck Inst Astrophys, D-85740 Garching, Germany. RP NASA, Goddard Space Flight Ctr, Hughes STX Corp, LASP, Code 685, Greenbelt, MD 20771 USA. RI Ratra, Bharat/I-4979-2012 NR 166 TC 47 Z9 47 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JAN PY 1998 VL 114 IS 1 BP 1 EP 36 DI 10.1086/313062 PG 36 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YP027 UT WOS:000071233900001 ER PT J AU George, IM Turner, TJ Netzer, H Nandra, K Mushotzky, RF Yaqoob, T AF George, IM Turner, TJ Netzer, H Nandra, K Mushotzky, RF Yaqoob, T TI ASCA observations of Seyfert 1 galaxies. III. The evidence for absorption and emission due to photoionized gas SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE galaxies, active; galaxies, nuclei; galaxies, Seyfert; X-rays, galaxies ID SOFT-X-RAY; ACTIVE GALACTIC NUCLEI; HOPKINS-ULTRAVIOLET-TELESCOPE; LONG-TERM VARIABILITY; IRON LINE EMISSION; C-IV ABSORPTION; SPECTRAL VARIABILITY; ACCRETION DISK; DETAILED OBSERVATIONS; IUE OBSERVATIONS AB We present the results from a detailed analysis of the 0.6-10 keV spectra of 23 ASCA observations of 18 objects. We find that in most cases the underlying continuum can be well represented by a power law with a photon index Gamma similar to 2. However, we find strong evidence for photoionized gas in the line of sight to 13/18 objects. We present detailed modeling of this gas based upon the ION photoionization code. Other studies have been made of the "warm absorber" phenomenon, but this paper contains the first consideration of the importance of the covering fraction of the ionized gas and a direct comparison between models of attenuation by ionized versus neutral material. We find the X-ray ionization parameter for the ionized material is strongly peaked at U-X similar to 0.1. The column densities of ionized material are typically in the range N-H,N-z similar to 10(21)-10(23) cm(-2), although highly ionized (and hence pseudotransparent) column densities up to 10(24) cm(-2) cannot be excluded in some cases. We also investigate the importance of the emission spectrum from the ionized gas, finding that it significantly improves the fit to many sources with an intensity consistent with material subtending a large solid angle at the central source. Allowing a fraction of the continuum to be observed without attenuation also improves the fit to many sources and is definitely required in the case of NGC 4151. A deficit of counts is observed at similar to 1 keV in the sources exhibiting the strongest absorption features. We suggest this is likely to be the signature of a second zone of (more highly) ionized gas, which might have been seen previously in the deep Fe K-shell edges observed in some Ginga observations. We find evidence that the ionized material in NGC 3227 and MCG -6-30-15 contains embedded dust, while there is no such evidence in the other sources. We discuss these results in the context of previous studies and briefly explore the implications in other wave bands. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. Univ Space Res Assoc, Washington, DC USA. RP George, IM (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 660, Greenbelt, MD 20771 USA. NR 156 TC 330 Z9 330 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JAN PY 1998 VL 114 IS 1 BP 73 EP 120 DI 10.1086/313067 PG 48 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YP027 UT WOS:000071233900004 ER PT J AU Chae, J Sun, HS Poland, AI AF Chae, J Sun, HS Poland, AI TI Temperature dependence of ultraviolet line average Doppler shifts in the quiet Sun SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE line, formation; line, profiles; Sun, transition region; Sun, UV radiation ID SOLAR TRANSITION REGION; OBSERVED REDSHIFTS; CHROMOSPHERE; CORONA; FLOWS; MODELS; TELESCOPE; DOWNFLOW; LOOPS AB The existence of prevailing redshifts in the UV lines formed in the solar transition region raises an important question concerning its physical origin and its role in the mass and energy balance of the outer solar atmosphere. A series of UV spectral lines observed by SUMER has been analyzed to obtain the spatial average of Doppler shifts in the quiet Sun as a function of temperature. The UV lines used for the analysis cover temperatures ranging from 10(4) to 10(6) K. The wavelength calibration has been done in reference to the coolest chromospheric lines such as neutral lines of silicon and sulfur. The positioning of the line center in blended lines has been made by employing a constrained multi-Gaussian fitting technique. The error in the measured average of the Doppler shifts is estimated to be smaller than 1 km s(-1). Our results show that the average Doppler shift at the base of the transition region is about 1-2 km s(-1), increasing with temperature with a peak value of 11 km s(-1) near T = 2.3 x 10(5) K. Then it decreases but remains still above zero (5 km s(-1) in Ne VIII lines and 4 km s(-1) in Mg x lines). We find that this behavior can be explained by the dominance of emission from plasma flowing downward from the upper hot region to the lower cool region along flux tubes with varying cross section. Assuming that pressure and mass flux are constant along a flux tube, the cross section of a typical flux tube has been estimated as a function of temperature. It turns out that the cross section is nearly constant below T = 10(5) K and then expands by a factor of about 30 at T = 10(6) K. This behavior is fairly well represented by an analytical functional form, A(T)/A(T-h) = [1 + (Gamma(2) - 1)(T/T-h)(v)](1/2)/Gamma with parameters of T-h = 10(6) K, Gamma = 30, and v = 3.6. C1 Seoul Natl Univ, Dept Astron, Seoul 151742, South Korea. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Solar Phys Branch, Greenbelt, MD 20771 USA. RP Seoul Natl Univ, Dept Astron, Seoul 151742, South Korea. NR 33 TC 132 Z9 132 U1 1 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JAN PY 1998 VL 114 IS 1 BP 151 EP 164 DI 10.1086/313064 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YP027 UT WOS:000071233900007 ER PT J AU Langer, WD Kuiper, TBH Velusamy, T AF Langer, WD Kuiper, TBH Velusamy, T TI CM wavelength spectral line mapping of protostellar cores SO ASTROPHYSICAL LETTERS & COMMUNICATIONS LA English DT Article; Proceedings Paper CT Conference on Molecular Spectroscopy in the 1 to 10 GHz Range with the Upgraded Arecibo Telescope CY OCT 19-20, 1995 CL ARECIBO OBSERV NATL ASTRONOMY & IONOSPHERE CTR, ARECIBO, PUERTO RICO HO ARECIBO OBSERV NATL ASTRONOMY & IONOSPHERE CTR DE interstellar medium : protostar formation; molecules; CCS : radio lines ID DENSE INTERSTELLAR CLOUDS; GAS-PHASE CHEMISTRY; B335; MOLECULES; CCS AB We study the structure and chemistry of the protostellar core B335 using high resolution spectral line observations of CCS with both single dish antennas and interferometers at cm wavelengths. B335 is a classical example of a young protostellar region containing both outflow and infall and is an ideal testbed for theoretical models of the collapse phase of protostar formation. We use combined VLA and single dish data to image the core around the protostar in B335. We find that CCS traces the outer parts of a collapsing envelope with a velocity and spatial structure consistent with dynamical models. However, CCS is absent in the interior of the infalling envelope which can only be explained with time dependent models of the protostar chemistry. Our work demonstrates the importance of spectral line mapping at cm wavelengths for understanding protostar evolution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Langer, WD (reprint author), CALTECH, Jet Prop Lab, MS 169-506, Pasadena, CA 91109 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0888-6512 J9 ASTROPHYS LETT COMM JI Astrophys. Lett. Comm. PY 1998 VL 37 IS 1-2 BP 59 EP 72 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZV549 UT WOS:000074316200006 ER PT J AU Meegan, C AF Meegan, C TI Gamma-ray bursts: Where are we now? SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Non-Sleeping Universe Conference CY NOV 24-29, 1997 CL UNIV PORTO, CTR ASTROPHYS, OPORTO, PORTUGAL SP Junta Nacl Investigacao Cientifica Technol, Ctr Astrofisica Univ Porto, Camara Municipal Porto, Inst Vinho Porto HO UNIV PORTO, CTR ASTROPHYS ID HUBBLE-SPACE-TELESCOPE; BATSE; AFTERGLOW; GALAXIES; ABSORPTION; GRB-970508; FEATURES; MODELS AB There has been significant progress recently in our understanding of gamma-ray bursts. The long-sought counterparts at other wavelengths have finally been found for a few bursts. This breakthrough is the result of coordinated observations involving several satellites and ground-based optical and radio observatories. In one case, GRB970508, redshifted absorption lines have been detected, finally settling the debate about the distance scale. The consensus is that the burst sources lie at cosmological distances, requiring at least similar to 10(51) ergs to be emitted in gamma rays in just a few seconds. The gamma radiation is thought to be produced by shocks in a highly relativistic fireball. Many mysteries remain. There is no consensus on the nature of the sources, although coalescing neutron stars are the leading candidate. There is evidence that the sources of the faintest bursts may be at redshifts above 2. If so, gamma-ray bursts may ultimately tell us something about the early Universe. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Meegan, C (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 45 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. PY 1998 VL 261 IS 1-4 BP 215 EP 224 DI 10.1023/A:1002069003927 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 249KU UT WOS:000083332900056 ER PT J AU Fleck, B AF Fleck, B TI First results from Soho SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 6th United Nations / European Space Agency Workshop CY SEP 09-13, 1996 CL BONN, GERMANY SP UN, European Space Agcy ID CORONAL DIAGNOSTIC SPECTROMETER; TIME-DISTANCE HELIOSEISMOLOGY; SUMER TELESCOPE; ERNE INSTRUMENT; SOLAR; OSCILLATIONS; MISSION; VIRGO; IMAGER; SUN AB SOHO, the Solar and Heliospheric Observatory, is a project of international cooperation between ESA and NASA to study the Sun, from its deep core to the outer corona, and the solar wind. Three helioseismology instruments are providing unique data for the study of the structure and dynamics of the solar interior, from the very deep core to the outermost layers of the convection zone. A set of five complementary remote sensing instruments, consisting of EUV, UV and visible light imagers, spectrographs and coronagraphs, give us our first comprehensive view of the outer solar atmosphere and corona, leading to a better understanding of the enigmatic coronal heating and solar wind acceleration processes. Finally, three experiments complement the remote sensing observations by making in-situ measurements of the composition and energy of the solar wind and charged energetic particles, and another instrument maps the neutral hydrogen in the heliosphere and its dynamic change by the solar wind. This paper reports some of the first results from the SOHO mission. C1 NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Greenbelt, MD 20771 USA. RP Fleck, B (reprint author), NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Greenbelt, MD 20771 USA. RI Fleck, Bernhard/C-9520-2012 NR 44 TC 1 Z9 1 U1 0 U2 2 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. PY 1998 VL 258 IS 1-2 BP 57 EP 75 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169YC UT WOS:000078776400008 ER PT J AU Perez, MR AF Perez, MR TI Alternative astronomical software packages SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT 6th United Nations / European Space Agency Workshop CY SEP 09-13, 1996 CL BONN, GERMANY SP UN, European Space Agcy AB At a time when the United Nations, in collaboration with Wolfram Research, has selected the Mathematica software package to inform developing countries about available scientific tools, it is important to review other choices of software being used by active scientists around the world. For observational astronomers with large volumes of digital data to be analyzed, the main challenges are data reductions, image handling, model comparisons, interactive fits, data simulations and visualizations, etc. There are several good alternative software packages such as: AIPS*,IRAF dagger, MIDAS double dagger and IDL . The first three packages can be obtained free of charge by contacting the sponsoring institutions. Information can be obtained, via the World Wide Web, from the URLs indicated in the footnotes. IDL is a commercial package that can be used in all kinds of computer platforms and is extensively used in space astronomy (e.g., main language of software reduction packages of missions like IUE, HST ROSAT, SOHO, etc). All of these packages are able to handle some of the most common commercial and scientific data formats (FITS, CDF and HDF). These software packages provide general tools for image processing and data reduction with emphasis on, but not limited to, astronomical applications. All of these packages have good active customer support strategies, the most useful ones being periodic newsletters, related meetings (e.g., annual meeting on Astronomical Data Analysis Software and Systems), software user groups, bulletin board discussions, FAQs, etc. The purpose of this paper is to present the relative usefulness, available platforms, associated libraries, related resources, of these software packages and the many already existing and potential astronomical applications. C1 NASA, GSFC, Space Applicat Corp, Largo, MD 20774 USA. RP Perez, MR (reprint author), NASA, GSFC, Space Applicat Corp, Largo, MD 20774 USA. NR 4 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. PY 1998 VL 258 IS 1-2 BP 271 EP 284 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 169YC UT WOS:000078776400023 ER PT J AU Grady, CA Perez, MR Bjorkman, KS Sitko, ML The, PS De Winter, D Grinin, VP Russell, RW Lynch, DK Hanner, MS AF Grady, CA Perez, MR Bjorkman, KS Sitko, ML The, PS De Winter, D Grinin, VP Russell, RW Lynch, DK Hanner, MS TI The intermittently embedded herbig Ae/Be stars - ISO and ground-based IR observations SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Conference on ISOs View on Stellar Evolution CY JUL 01-04, 1997 CL NOORDWIJKERHOUT, NETHERLANDS SP Space Res Org Netherlands, Astron Inst Anton Pannekoek, Univ Amsterdam, Kapteyn Fund ID BETA-PICTORIS PHENOMENON; CIRCUMSTELLAR DUST SHELL; YOUNG STARS; ACCRETION DISKS; WW-VULPECULAE; AE STARS; VARIABILITY; PHOTOMETRY; HD-100546; HD-104237 AB We discuss silicate emission profiles observed with the ISO SWS and ground-based IR observations in a population of intermittently embedded Herbig Ae/Be stars which are viewed edge-on to their polarimetrically identified dust and gas disks. The ISO SWS observations confirm the lack of a simple correlation between system age and the profile shape. Comparison with laboratory silicates suggests that much of the observed variation is due to different annealing histories of the grains. C1 Eureka Sci, Laurel, MD USA. Space Appl Corp, Landover, MD USA. Univ Toledo, Ritter Observ, Toledo, OH 43606 USA. Univ Toledo, Dept Phys, Toledo, OH 43606 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, Amsterdam, Netherlands. Univ Autonoma Madrid, Dept Fis Teor, Madrid 28048, Spain. Crimean Astrophys Observ, UA-334413 Nauchnyi, Ukraine. Aerospace Corp, Los Angeles, CA 90009 USA. CALTECH, JPL, Pasadena, CA 91125 USA. RP Grady, CA (reprint author), Eureka Sci, Laurel, MD USA. RI Grinin, Vladimir/M-9509-2013 OI Grinin, Vladimir/0000-0001-8923-9541 NR 36 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1998 VL 255 IS 1-2 BP 35 EP 42 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111YE UT WOS:000075465800005 ER PT J AU Van den Ancker, ME Wesselius, PR Tielens, AGGM Waters, LBFM AF Van den Ancker, ME Wesselius, PR Tielens, AGGM Waters, LBFM TI PDRs and shocks in S106 IR and Cep A East SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Conference on ISOs View on Stellar Evolution CY JUL 01-04, 1997 CL NOORDWIJKERHOUT, NETHERLANDS SP Space Res Org Netherlands, Astron Inst Anton Pannekoek, Univ Amsterdam, Kapteyn Fund ID INTERSTELLAR SHOCKS; BIPOLAR NEBULA; EXCITATION; EMISSION; S-106; MODEL AB We present SWS grating scans of pure H-2 rotational lines, as well as several infrared fine-structure lines for two embedded Young Stellar Objects, S106 IR and Cep A East. Excitation temperatures and masses were derived from the low-lying pure rotational levels of H-2 and are 490 and 740 K and 0.04 and 0.007 M. for S106 and Cep A, respectively. The observations were compared to theoretical models for PDRs and dissociative and non-dissociative shocks. The infrared spectrum of S106 IR is dominated by PDR emission while that of Cep A East has a large shock component. We suggest that the difference between these two objects could reflect an evolutionary trend. C1 Univ Amsterdam, Astron Inst, NL-1012 WX Amsterdam, Netherlands. SRON Groningen, Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Van den Ancker, ME (reprint author), Univ Amsterdam, Astron Inst, NL-1012 WX Amsterdam, Netherlands. NR 10 TC 9 Z9 9 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. PY 1998 VL 255 IS 1-2 BP 69 EP 76 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111YE UT WOS:000075465800011 ER PT J AU Van Dishoeck, EF Thi, WF Blake, GA Mannings, V Sargent, AI Koerner, D Mundy, LG AF Van Dishoeck, EF Thi, WF Blake, GA Mannings, V Sargent, AI Koerner, D Mundy, LG TI Search for H-2 emission from disks around T Tauri and Herbig AE stars SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Conference on ISOs View on Stellar Evolution CY JUL 01-04, 1997 CL NOORDWIJKERHOUT, NETHERLANDS SP Space Res Org Netherlands, Astron Inst Anton Pannekoek, Univ Amsterdam, Kapteyn Fund ID YOUNG STELLAR OBJECTS; CIRCUMSTELLAR DISKS; ACCRETION DISKS; GAS AB Preliminary results are presented of observations of the pure rotational lines of H-2 toward T Tauri and Herbig Ae stars using the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). The sources are selected to be isolated low- and intermediate-mass young stellar objects, for which the presence of a circumstellar disk has been established by millimeter interferometry. The lowest H-2 S(0) and S(1) lines are detected in 3 out of 5 objects. The measured intensities indicate similar to 0.01 M. of warm (T approximate to 150 K) gas in the ISO beam. It is argued that for at least one case (HD 163296), the emission is probably dominated by the warm gas in the circumstellar disk rather than by shocked- or photon-heated gas in the surrounding envelope. Such observations can provide important constraints on the radial and vertical temperature profiles in circumstellar disks. C1 Leiden Observ, NL-2300 RA Leiden, Netherlands. CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, College Pk, MD 20742 USA. RP Van Dishoeck, EF (reprint author), Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands. NR 16 TC 9 Z9 9 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. PY 1998 VL 255 IS 1-2 BP 77 EP 82 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111YE UT WOS:000075465800012 ER PT J AU Hallenbeck, S Nuth, J AF Hallenbeck, S Nuth, J TI Infrared observations of the transition from chaotic to crystalline silicates via thermal annealing in the laboratory SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Conference on ISOs View on Stellar Evolution CY JUL 01-04, 1997 CL NOORDWIJKERHOUT, NETHERLANDS SP Space Res Org Netherlands, Astron Inst Anton Pannekoek, Univ Amsterdam, Kapteyn Fund ID EMISSION FEATURE; SPECTRUM; DUST; SPECTROSCOPY; OLIVINE; GLASSES; HALLEY; MELTS C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hallenbeck, S (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Nuth, Joseph/E-7085-2012 NR 18 TC 14 Z9 14 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. PY 1998 VL 255 IS 1-2 BP 427 EP 433 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111YE UT WOS:000075465800072 ER PT J AU Geballe, TR Chiar, J Pendleton, YJ Tielens, AGGM AF Geballe, TR Chiar, J Pendleton, YJ Tielens, AGGM TI The 3.4 microns absorption feature in CRL 618 SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Conference on ISOs View on Stellar Evolution CY JUL 01-04, 1997 CL NOORDWIJKERHOUT, NETHERLANDS SP Space Res Org Netherlands, Astron Inst Anton Pannekoek, Univ Amsterdam, Kapteyn Fund ID INTERSTELLAR C1 Joint Astron Ctr, Hilo, HI 96720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Geballe, TR (reprint author), Joint Astron Ctr, 665 Komohana St, Hilo, HI 96720 USA. NR 7 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. PY 1998 VL 255 IS 1-2 BP 457 EP 458 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 111YE UT WOS:000075465800077 ER PT J AU Quattrochi, DA Ridd, MK AF Quattrochi, DA Ridd, MK TI Analysis of vegetation within a semi-arid urban environment using high spatial resolution airborne thermal infrared remote sensing data SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT Conference on the Benefits of the Urban Forest CY MAR 07, 1995 CL SACRAMENTO, CA SP Sacramento Municipal Util Dist DE thermal remote sensing; urban vegetation; urban surface energy fluxes ID HEAT ISLANDS; CLIMATOLOGY AB High spatial resolution (5m) remote sensing data obtained using the airborne Thermal Infrared Multispectral Scanner (TIMS) sensor for daytime and nighttime have been used to measure thermal energy responses for 2 broad classes and 10 subclasses of vegetation typical of the Salt Lake City, Utah urban landscape. Polygons representing discrete areas corresponding to the 10 subclasses of vegetation types have been delineated from the remote sensing data and are used for analysis of upwelling thermal energy for day, night, and the change in response between day and night or flux, as measured by the TIMS. These data have been used to produce three-dimensional graphs of energy responses in Wm(-2) for day, night, and flux, for each urban vegetation land cover as measured by each of the six channels of the TIMS sensor. Analysis of these graphs provides a unique perspective for both viewing and understanding thermal responses, as recorded by the TIMS, for selected vegetation types common to Salt Lake City. A descriptive interpretation is given for each of the day, night, and flux graphs along with an analysis of what the patterns mean in reference to the thermal properties of the vegetation types surveyed in this study. From analyses of these graphs, it is apparent that thermal responses for vegetation can be highly varied as a function of the biophysical properties of the vegetation itself, as well as other factors. Moreover, it is also seen where vegetation, particularly trees, has a significant influence on damping or mitigating the amount of thermal radiation upwelling into the atmosphere across the Salt Lake City urban landscape. Published by Elsevier Science Ltd. C1 UNIV UTAH, DEPT GEOG, SALT LAKE CITY, UT 84112 USA. RP NASA, GLOBAL HYDROL & CLIMATE CTR, HR01, MARSHALL SPACE FLIGHT CTR, AL 35812 USA. NR 24 TC 36 Z9 38 U1 1 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD JAN PY 1998 VL 32 IS 1 BP 19 EP 33 DI 10.1016/S1352-2310(97)00179-9 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA YJ504 UT WOS:A1998YJ50400004 ER PT J AU Cofer, WR Anderson, BE Winstead, EL Bagwell, DR AF Cofer, WR Anderson, BE Winstead, EL Bagwell, DR TI Calibration and demonstration of a condensation nuclei counting system for airborne measurements of aircraft exhausted particles SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE aerosols; condensation nuclei; aircraft exhaust; contrails ID SIZE DISTRIBUTION; ANTHROPOGENIC AEROSOLS; COMBUSTION AEROSOLS; CONTRAIL FORMATION; LOWER STRATOSPHERE; SULFUR EMISSIONS; CLIMATE; TROPOSPHERE; PERFORMANCE; NUCLEATION AB A system of multiple continuous-flow condensation nuclei counters (CNC) was assembled, calibrated, and demonstrated on a NASA T-39 Sabreliner jet aircraft. The mission was to penetrate the exhaust plumes and/or contrails of other subsonic jet aircraft and determine the concentrations of submicrometer diameter aerosol particles. Mission criteria required rapid response measurements (similar to 1 s) at aircraft cruise altitudes (9-12 km). The CNC sampling system was optimized to operate at 160 Torr. Aerosol samples were acquired through an externally mounted probe. Installed downstream of the probe was a critical flow orifice that provided sample to the CNC system. The orifice not only controlled volumetric flow rate, but also dampened probe pressure/flow oscillations encountered in the turbulent aircraft-wake vortex environment. Laboratory calibrations with NaCl particles under representative conditions are reported that indicate small amounts of particle loss and a maximum measurement efficiency of similar to 75% for particles with diameters ranging from greater than or equal to 0.01-less than or equal to 0.18 mu m. Data from exhaust/contrail samplings of a NASA B757 and DC-8 at cruise altitude are discussed. Data include exhaust/contrail measurements made during periods in which the B757 port jet engine burned low-sulfur fuel while the starboard engine simultaneously burned specially prepared high-sulfur Fuel. The data discussed highlight the CNC systems performance, and introduce new observations pertinent to the behavior of sulfur in aircraft exhaust aerosol chemistry. (C) 1997. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Div Operat Support, Hampton, VA 23681 USA. RP Cofer, WR (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, 28 Res Dr, Hampton, VA 23681 USA. NR 38 TC 10 Z9 10 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JAN PY 1998 VL 32 IS 2 BP 169 EP 177 DI 10.1016/S1352-2310(97)00318-X PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA YM849 UT WOS:000071107700007 ER PT S AU Bilitza, D AF Bilitza, D BE Shepherd, GG Singer, W TI The E- and D-region in IRI SO ATMOSPHERIC TIDAL DYNAMICS AND E- AND D-REGION PHYSICS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT CO 1 and C4 1 Symposia of COSPAR Scientific Commission C - Atmospheric Tidal Dynamics and E-Region and D-Region Physics, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Un Off Outer Space Affairs ID INTERNATIONAL REFERENCE IONOSPHERE; ION COMPOSITION; MODEL; TWILIGHT AB The International Reference Ionosphere provides a representation of the electron density and the ion composition in the E-and D-region (from 60 km upward) based on measurements from the ground (ionosonde, incoherent scatter) and from rockets. We will review the current status of the IRI E-and D-region models and discuss recent improvements and plans for future updates. Shortcomings and limits of the present description will be pointed out and the need for more measurements will be stressed. We will also discuss other venues of model improvement, e.g., results from theoretical models and input of measured characteristic parameters (E peak, D ledge). (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Natl Space Sci Data Ctr, HSTX, Greenbelt, MD 20771 USA. RP Bilitza, D (reprint author), NASA, Goddard Space Flight Ctr, Natl Space Sci Data Ctr, HSTX, Code 633, Greenbelt, MD 20771 USA. NR 24 TC 9 Z9 11 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043459-2 J9 ADV SPACE RES PY 1998 VL 21 IS 6 BP 871 EP 874 DI 10.1016/S0273-1177(97)00645-5 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK95H UT WOS:000073936200015 ER PT S AU Brown, LR AF Brown, LR BE Mohr, PJ Wiese, WL TI Atomic and molecular databases for planetary and terrestrial applications SO ATOMIC AND MOLECULAR DATA AND THEIR APPLICATIONS: ICAMDATA - FIRST INTERNATIONAL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1st International Conference on Atomic and Molecular Data and Their Applications (ICAMDATA) CY SEP 29-OCT 02, 1997 CL NATL INST STAND & TECHNOL, GAITHERSBURG, MD SP Amer Inst Phys, US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Stand Reference Data Program, Natl Inst Stand & Technol, Atom Phys Div, Phys Lab, Elect Power Res Inst, US DOE, Off Fus Energy Sci, Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Molec Phys, USN, Naval Res Lab, SEMATECH, NASA, Off Space Sci HO NATL INST STAND & TECHNOL AB Characteristics of solar and planetary atmospheres ranging from chemical composition to climate can be accurately measured through spectroscopic remote sensing. Fundamental principles of physics and chemistry cart then be applied to interpret the atmospheric observations (with varying degrees of success). The models of planetary atmospheres to simulate the chemistry, radiation fields, and/or dynamics require knowledge of many molecular properties ranging from photochemical and kinetic information to atomic and molecular transition parameters. Both the experimental and theoretical efforts require detailed databases of spectral parameters for use in computer simulations. The status of current databases for theoretical models and for microwave and infrared observations will be presented along with an overview of the problems associated with maintaining them. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brown, LR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-751-0 J9 AIP CONF PROC PY 1998 VL 434 BP 159 EP 190 PG 32 WC Physics, Applied; Physics, Atomic, Molecular & Chemical; Physics, Multidisciplinary SC Physics GA BL48Y UT WOS:000075685200012 ER PT S AU Kallman, TR AF Kallman, TR BE Mohr, PJ Wiese, WL TI Atomic data and modelling in X-ray astronomy SO ATOMIC AND MOLECULAR DATA AND THEIR APPLICATIONS: ICAMDATA - FIRST INTERNATIONAL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1st International Conference on Atomic and Molecular Data and Their Applications (ICAMDATA) CY SEP 29-OCT 02, 1997 CL NATL INST STAND & TECHNOL, GAITHERSBURG, MD SP Amer Inst Phys, US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Stand Reference Data Program, Natl Inst Stand & Technol, Atom Phys Div, Phys Lab, Elect Power Res Inst, US DOE, Off Fus Energy Sci, Harvard Smithsonian Ctr Astrophys, Inst Theoret Atom & Molec Phys, USN, Naval Res Lab, SEMATECH, NASA, Off Space Sci HO NATL INST STAND & TECHNOL AB In the next 3 years the study of astronomical X-ray spectra will make a significant advance owing to the launch of several new instruments. These will represent an order of magnitude improvement in both spectral resolving power and sensitivity over current instruments, and will allow use of plasma diagnostics which have not been previously accesible. In this talk I will illustrate some of the uses of such diagnostics. I will discuss the status of the atomic data available, and point out areas where work is most urgently needed. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-751-0 J9 AIP CONF PROC PY 1998 VL 434 BP 203 EP 212 PG 10 WC Physics, Applied; Physics, Atomic, Molecular & Chemical; Physics, Multidisciplinary SC Physics GA BL48Y UT WOS:000075685200014 ER PT J AU Bhatia, AK Doschek, CA AF Bhatia, AK Doschek, CA TI Atomic data and spectral line intensities for Ni XIII SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID CROSS-SECTIONS; TRANSITIONS; EXCITATION; IX AB Electron impact collision strengths and spontaneous radiative decay rates are calculated for Ni XIII. The data pertain to the 48 levels of the configurations 3s(2)3p(4), 3s3p(5), 3s(2)3p(3)3d, and 3p(6). Collision strengths are calculated at five incident electron energies: 10.0, 20.0, 30.0, 40.0, and 50.0 Ry. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients (cm(3) s(-1)), i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 48 energy levels, assuming a collisional excitation model and an electron temperature of 2.0 x 10(6) K. This temperature is typical for Ni XIII when formed in equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are given in this paper. We also investigate the effects of proton excitation and solar radiative excitation on the level populations and line intensities. (C) 1998 Academic Press. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 20 TC 5 Z9 5 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD JAN PY 1998 VL 68 IS 1 BP 49 EP 90 DI 10.1006/adnd.1997.0757 PG 42 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA ZE154 UT WOS:000072763500002 ER PT S AU Chutjian, A Greenwood, JB Smith, SJ AF Chutjian, A Greenwood, JB Smith, SJ BE Oks, E Pindzola, MS TI Low-energy electron collisions with multiply-charged positive ions SO ATOMIC PROCESSES IN PLASMAS: ELEVENTH APS TOPICAL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 11th APS Topical Conference on Atomic Processes in Plasmas CY MAR 23-26, 1998 CL AUBURN, AL AB Cross sections for a variety of electron-ion collision phenomena are the backbone for understanding energy balance in high electron temperature plasmas. Such plasmas include such seemingly disparate objects such as the Io torus around Jupiter, solar and stellar atmospheres, the interstellar medium, and fusion devices. Several experimental approaches used with multiply-charged ions (MCIs) will be reviewed. These include measurement of excitation cross sections using the electron energy-loss method, measurement of ionic lifetimes using a Kingdon trap, and measurement of dissociative recombination cross sections using ion storage rings. New JPL results will be presented of e-S2+ inelastic scattering, relevant to the problem of ion density and radiated energy in the Io torus; and metastable-state lifetimes in C+, N+, and Ar2+ relevant to stellar absorption by the interstellar medium. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chutjian, A (reprint author), CALTECH, Jet Prop Lab, MS 121-114,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Greenwood, Jason/L-4799-2014 NR 0 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-802-9 J9 AIP CONF PROC PY 1998 VL 443 BP 134 EP 148 DI 10.1063/1.56569 PG 15 WC Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical SC Physics GA BL94X UT WOS:000077262700011 ER PT S AU Kucera, TA AF Kucera, TA BE Oks, E Pindzola, MS TI SOHO: Atomic physics and the solar atmosphere SO ATOMIC PROCESSES IN PLASMAS: ELEVENTH APS TOPICAL CONFERENCE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 11th APS Topical Conference on Atomic Processes in Plasmas CY MAR 23-26, 1998 CL AUBURN, AL AB Many aspects of the Sun's corona and wind are studied using data from the ultraviolet spectrum. Accurate atomic parameters are needed to interpret these data correctly, and a good understanding of the behaviors of atoms and ions in plasmas is essential to modeling the Sun's atmosphere. Here I present two examples of studies being carried out using the Solar and Heliospheric Observatory (SOHO) extreme ultraviolet spectrographs. The first of these is the study of hows in the Sun's chromosphere and corona. SOHO has provided new information concerning previous observations of the predominant down-flows in the Sun's lower atmosphere. Accurate measurements of Doppler line shifts have been extended to the corona. It has also been found that the Doppler shifts vary over different parts of the Sun. The second study discussed involves the use of SOHO data to measure elemental abundances in coronal structures know as streamers, giving more information on the "FIP" effect - the observation that there is a relative deficit of elements with high first ionization potentials (FIPs) ill the corona and solar wind. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kucera, TA (reprint author), NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. RI Kucera, Therese/C-9558-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-802-9 J9 AIP CONF PROC PY 1998 VL 443 BP 173 EP 184 DI 10.1063/1.56548 PG 12 WC Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical SC Physics GA BL94X UT WOS:000077262700014 ER PT S AU Smith, CC Ila, D Williams, EK Poker, DB Hensley, DK AF Smith, CC Ila, D Williams, EK Poker, DB Hensley, DK BE Barbour, JC Roorda, S Ila, D Tsujioka, M TI The optical properties of ion implanted silica SO ATOMISTIC MECHANISMS IN BEAM SYNTHESIS AND IRRADIATION OF MATERIALS SE Materials Research Society Symposium Proceedings LA English DT Proceedings Paper CT Symposium KK - on Atomistic Mechanisms in Beam Synthesis and Irradiation of Materials at the 1997 MRS Fall Meeting CY DEC 01-02, 1997 CL BOSTON, MA SP Mat Res Soc, Alabama A&M Univ, Ctr Irradiation Mat, High Volage Engn Europa B.v., Natl Electrostatics Corp, Sumitomo Elect Ind Ltd ID GLASS AB We present the results of our investigation of the change in the optical properties of silica, "suprasil", after keV through MeV implantation of copper, tin, silver and gold and after annealing. Suprasil, name brand of silica glass produced by Hereaus Amersil, which is chemically highly pure with well known optical properties. Both linear and nonlinear optical properties of the implanted silica were investigated before and after thermal annealing. All implants showed strong optical absorption bands in agreement with Mie theory. For implants with a measurable optical absorption band we used Doyle's theory and the full width half maximum of the absorption band to calculate the predicted size of the formed nanoclusters at various heat treatment temperatures. These results are compared with those obtained from direct observation using transmission electron microscopic techniques. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Smith, CC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-409-2 J9 MATER RES SOC SYMP P PY 1998 VL 504 BP 351 EP 356 PG 6 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BM67L UT WOS:000079427800052 ER PT J AU Lin, GH Marino, BDV Wei, YD Adams, J Tubiello, F Berry, JA AF Lin, GH Marino, BDV Wei, YD Adams, J Tubiello, F Berry, JA TI An experimental and modeling study of responses in ecosystems carbon exchanges to increasing CO2 concentrations using a tropical rainforest mesocosm SO AUSTRALIAN JOURNAL OF PLANT PHYSIOLOGY LA English DT Article ID ELEVATED CO2; RAIN-FOREST; DIOXIDE; PHOTOSYNTHESIS; ASSIMILATION; ACCLIMATION; PHYSIOLOGY; BIOSPHERE; AMAZONIA; PLANTS AB The ecosystem carbon exchanges in the enclosed rainforest of Biosphere 2, an enclosed apparatus comprised of large synthetic ecosystems, were measured and modeled during the winter of 1995-1996 under different atmospheric CO2 concentrations. On eight separate days, this mesocosm was exposed to various levels of CO2 ranging from about 380 to 820 mu mol mol(-1) daily mean and then sealed 24 hours for continuous measurements of ecosystem CO2 fluxes. Our results indicated that net ecosystem carbon exchange in the mesocosm was enhanced by increasing CO2 over the short periods studied (2-7 weeks), but, as expected from physiological studies, the response is not linear. The main effect of shortterm CO2 change was the enhancement of canopy CO2 assimilation, while soil respiration was not affected by the atmospheric CO2 concentration. The whole ecosystem radiation use efficiency was significantly higher under higher CO2. The results of direct measurements were predicted well by a simple canopy model (the 'big-leaf' model) that incorporates current physiological understanding of the biochemistry of leaf photosynthesis. Validation of this model with a range of CO2 and light levels indicates that it can be used with confidence to predict the responses of natural ecosystems to global climate change. Response of ecosystem processes to elevated CO2 with relaxation time longer than a few weeks could not be resolved in this study, but longer-term closure experiments are planned to examine these processes. C1 Columbia Univ, Biosphere Ctr 2, Oracle, AZ 85623 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94035 USA. RP Lin, GH (reprint author), Columbia Univ, Biosphere Ctr 2, Oracle, AZ 85623 USA. RI Lin, GH/G-4593-2010; Lin, Guanghui/I-6850-2013; OI Lin, Guanghui/0000-0001-6108-3215; Berry, Joseph A/0000-0002-5849-6438 NR 31 TC 30 Z9 33 U1 0 U2 8 PU C S I R O PUBLICATIONS PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA SN 0310-7841 J9 AUST J PLANT PHYSIOL JI Aust. J. Plant Physiol. PY 1998 VL 25 IS 5 BP 547 EP 556 PG 10 WC Plant Sciences SC Plant Sciences GA 109PF UT WOS:000075331100006 ER PT S AU Wallace, RG Affens, DW McCandless, SW AF Wallace, RG Affens, DW McCandless, SW BE Sadjadi, FA TI Search and rescue from space SO AUTOMATIC TARGET RECOGNITION VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Automatic Target Recognition VIII CY APR 13-17, 1998 CL ORLANDO, FL SP SPIE DE Search and Rescue; synthetic aperture radar (SAR); automatic target recognition; interferometry; coherent; change detection AB The NASA Search and Rescue Mission was originated to develop a space-based emergency beacon detection system. The Sarsat system, along with its Russian counterpart - Cospas, is highly successful and credited with the saving of over 8,000 lives worldwide during its 16 years of operation. Now, new techniques are emerging which may make it possible to locate downed aircraft wreckage from space without the need for a functioning emergency beacon. This paper reviews existing space and airborne systems and discusses the potential for space borne application of recent advances in techniques for interferometric SAR, coherent change detection, real time processing and polarimetric ATR to the search and rescue problem. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wallace, RG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2820-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3371 BP 174 EP 184 DI 10.1117/12.323835 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL85K UT WOS:000076932900017 ER PT J AU Pell, B Bernard, DE Chien, SA Gat, E Muscettola, N Nayak, PP AF Pell, B Bernard, DE Chien, SA Gat, E Muscettola, N Nayak, PP TI An autonomous spacecraft agent prototype SO AUTONOMOUS ROBOTS LA English DT Article; Proceedings Paper CT 1st International Conference on Autonomous Agents CY FEB, 1997 CL SANTA MONICA, CALIFORNIA DE autonomous robots; agent architectures; action selection and planning; diagnosis; integration and coordination of multiple activities; fault protection; operations; real-time systems; modeling ID ENVIRONMENTS AB This paper describes the New Millennium Remote Agent (NMRA) architecture for autonomous spacecraft control systems. The architecture supports challenging requirements of the autonomous spacecraft domain not usually addressed in mobile robot architectures, including highly reliable autonomous operations over extended time periods in the presence of tight resource constraints, hard deadlines, limited observability, and concurrent activity. A hybrid architecture, NMRA integrates traditional real-time monitoring and control with heterogeneous components for constraint-based planning and scheduling, robust multi-threaded execution, and model-based diagnosis and reconfiguration. Novel features of this integrated architecture include support for robust closed-loop generation and execution of concurrent temporal plans and a hybrid procedural/deductive executive. We implemented a prototype autonomous spacecraft agent within the architecture and successfully demonstrated the prototype in the context of a challenging autonomous mission scenario on a simulated spacecraft. As a result of this success, the integrated architecture has been selected to fly as an autonomy experiment on Deep Space One (DS-1), the first flight of NASA's New Millennium Program (NMP), which will launch in 1998. It will be the first AI system to autonomously control an actual spacecraft. C1 NASA, Ames Res Ctr, Caelum Res Corp, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Recom Technol, Moffett Field, CA 94035 USA. Fourth Planet Inc, Los Altos, CA 94022 USA. RP Pell, B (reprint author), NASA, Ames Res Ctr, Caelum Res Corp, MS 269-2, Moffett Field, CA 94035 USA. NR 49 TC 13 Z9 15 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PY 1998 VL 5 IS 1 BP 29 EP 52 DI 10.1023/A:1008860925034 PG 24 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA ZH931 UT WOS:000073162200004 ER PT J AU Conkin, J Powell, MR Foster, PP Waligora, JM AF Conkin, J Powell, MR Foster, PP Waligora, JM TI Information about venous gas emboli improves prediction of hypobaric decompression sickness SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID EXTRAVEHICULAR ACTIVITIES; BUBBLES; SYMPTOMS; TIME; RISK AB Hypothesis: information about venous gas emboli (VGE) detected in the pulmonary artery such as the occurrence of VGE, Grade of VGE, the time when VGE first appear, and the rime course of the Grade or occurrence of VGE, could be used to better assess the probability of decompression sickness [P(DCS)] in any hypobaric decompression. We hypothesized that these data would improve the estimate of P(DCS) since objective measurements of the decompression stress are available for the individual. Methods: A binary correlation and survival analysis approach were used on information from 1,322 hypobaric chamber exposures to establish the relationships between VGE and DCS. Results: Based on the correlation analysis, the absence of VGE is highly correlated with the absence of a DCS symptom, as evident from a negative predictive value of 0.98. However, the presence of VGE in the pulmonary artery is not highly correlated with a subsequent DCS symptom, as evident from a positive predictive value of 0.39 for Grades Ill and IV VGE. The correlation results suggest the presence of VGE in the pulmonary artery is a necessary, but not sufficient, condition for DCS. Based on the survival analysis, the log logistic survival model, a one-variable model with two parameters gave a log likelihood (LL) of -757. This model was expanded to include seven additional variables, including four about VGE, and the nine-parameter model gave a better LL of -481. Conclusion: Information about VGE plus other variables known to influence DCS is useful to better assess the P(DCS) for hypobaric decompressions. C1 NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Univ Space Res Assoc, Div Space Life Sci, Houston, TX USA. RP Conkin, J (reprint author), NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. NR 22 TC 26 Z9 26 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JAN PY 1998 VL 69 IS 1 BP 8 EP 16 PG 9 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA YQ550 UT WOS:000071399000002 PM 9451528 ER PT J AU Hsieh, ST Ballard, RE Murthy, G Hargens, AR Convertino, VA AF Hsieh, ST Ballard, RE Murthy, G Hargens, AR Convertino, VA TI Plasma colloid osmotic pressure increases in humans during simulated microgravity SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID HEAD-DOWN TILT; BED REST; FLUID SHIFTS; HEMATOCRIT; RESPONSES; EXERCISE; VOLUME; SPACE AB Background: On exposure to microgravity, astronauts lose up to 12% of their plasma volume which may contribute to post-flight orthostatic intolerance. Hypothesis: Whole-body dehydration during prolonged microgravity, simulated by 6 degrees head-down tilt (HDT), may increase plasma colloid osmotic pressure (COP). Methods: There were seven healthy male subjects (30-55 yr of age) were placed in 6 degrees HDT for 16 d. Plasma COP was measured from blood samples drawn immediately before HDT, on day 14 of HDT, and 1 h following bed rest termination using a 20 mu L colloid osmometer. Plasma volume was determined before HDT, on day 16 of HDT, and 1 h following bed rest termination using a modified Evans blue dye technique. Results: Plasma COP on day 14 of bed rest (29.9 +/- 0.7 mm Hg) was higher (p = 0.001) than pre-HDT value (23.1 +/- 0.8 mm Hg), coinciding with a decrease of plasma volume. At 1 h of upright recovery following HDT, plasma volume stayed below baseline and plasma COP remained elevated (26.6 +/- 0.6 mm Hg; p = 0.003) as compared with the pre HDT value. Conclusion: Our results indicate that reduced plasma volume and significantly elevated plasma COP probably reflect an overall loss of extracellular fluids during simulated microgravity. C1 NASA, Ames Res Ctr, Gravitat Res Branch 23911, Moffett Field, CA 94035 USA. Div Clin Sci, Brooks AFB, TX USA. RP Hargens, AR (reprint author), NASA, Ames Res Ctr, Gravitat Res Branch 23911, Moffett Field, CA 94035 USA. NR 28 TC 4 Z9 5 U1 0 U2 2 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JAN PY 1998 VL 69 IS 1 BP 23 EP 26 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA YQ550 UT WOS:000071399000004 PM 9490611 ER PT S AU Starks, SA Kreinovich, V AF Starks, SA Kreinovich, V BE MohammadDjafari, A TI Multi-spectral inverse problems in satellite image processing SO BAYESIAN INFERENCE FOR INVERSE PROBLEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Bayesian Inference for Inverse Problems CY JUL 23-24, 1998 CL SAN DIEGO, CA SP SPIE, Int Soc Opt Engn DE inverse problem; multi-spectral inverse problem; satellite imaging AB Satellite imaging is nowadays one of the main sources of geophysical and environmental information. It is, therefore, extremely important to be able to solve the corresponding inverse problem: reconstruct the actual geophysics- or environment-related image from the observed noisy data. Traditional image reconstruction techniques have been developed for the case when we have a single observed image. This case corresponds to a single satellite photo. Existing satellites (e.g., Landsat) take photos in several (up to 7) wavelengths. To process this multiple-spectral information, we can use known reasonable multi-image modifications of the existing single-image reconstructing techniques. These modifications, basically, handle each image separately, and try to merge the resulting information. Currently, a new generation of imaging satellites (Lewis) is being launched, that will enable us to collect visual images for about 500 different wavelengths. This two order of magnitude increase in data amount should lead to a similar increase in the processing time, but surprisingly, it does not. An analysis and explanation of this paradoxical simplicity is given in the paper. C1 Univ Texas, NASA, Pan Amer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. RP Starks, SA (reprint author), Univ Texas, NASA, Pan Amer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2914-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3459 BP 138 EP 146 DI 10.1117/12.323793 PG 9 WC Mathematics, Applied SC Mathematics GA BM20M UT WOS:000078027500015 ER PT B AU Kolb, EW AF Kolb, EW BE KlapdorKleingrothaus, HV Pas, H TI Who is the inflaton? SO BEYOND THE DESERT 1997: ACCELERATOR AND NON-ACCELERATOR APPROACHES LA English DT Proceedings Paper CT 1st International Conference on Particle Physics Beyond the Standard Model CY JUN 08-14, 1997 CL CASTLE RINGBERG, GERMANY ID DARK-MATTER; MICROWAVE; ANISOTROPY; COSMOLOGY; EVOLUTION; MODELS AB Inflation is now established as part of our picture of the very early universe. There are many particle physics models of inflation; some based on superstrings, some based on supersymmetry, and some seemingly based on superstition. But which model, if any, is correct? In this talk I will discuss how we might be able to learn something about the particle physics foundation of inflation from present observations of the angular power spectrum of cosmic background radiation temperature fluctuations and the power spectrum of fluctuations in the distribution of matter. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Kolb, EW (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0489-8 PY 1998 BP 725 EP 747 PG 23 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BN24E UT WOS:000081235100053 ER PT S AU Somps, CJ Madou, MJ Hines, JW AF Somps, CJ Madou, MJ Hines, JW BE Lieberman, RA VoDinh, T Katzir, A TI Microfabricated electrochemical sensors for chronic physiologic monitoring SO BIOMEDICAL SENSING AND IMAGING TECHNOLOGIES, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Biomedical Sensing and Imaging Technologies CY JAN 26-27, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers, Int Biomed Opt Soc DE microfabrication; electrolytes; blood gases; polymer membrane; in vivo; ex vivo AB NASA is developing miniaturized electrolyte and blood gas sensors to aid investigations into the influence of space flight on physiologic systems. These sensors are being applied in ex vivo blood flow loops as well as in in vivo wireless telemetric configurations. Our development approach is to first implement sensors in simple hand-made miniaturized catheter shaped configurations, and then migrate to micro planar configurations compatible with low-cost mass production. Catheter-based sensors are used for materials performance and biocompatibility testing, and for systems level integration, demonstration, and evaluation. For example, we have shown that pH sensitive polymer membranes cast on miniaturized catheters survive chronic implantation in rat subcutaneous tissue for periods up to 12 weeks with little loss in performance characteristics such as drift, sensitivity, selectivity, and response time. Microfabrication options for electrochemical sensors are based on a combination of thin and thick film technology with inexpensive non-silicon substrates. For the inorganic layers we are working with thin film evaporation and silk-screening, and for the organic layers we are comparing drop delivery and silk-screen approaches. The electrochemical cells are contacted from the back-side and each type of sensor is optimized on a separately fabricated substrate. Sensor combinations are then put into any desired array configuration with pick-and-place technology. This modular approach has many advantages over the integrated sensor approach which has been promoted as the ideal sensor solution for many years. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Somps, CJ (reprint author), NASA, Ames Res Ctr, MS 213-2, Moffett Field, CA 94035 USA. RI Madou, Marc/E-5869-2013 OI Madou, Marc/0000-0003-4847-3117 NR 0 TC 0 Z9 0 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2692-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3253 BP 199 EP 207 DI 10.1117/12.308030 PG 9 WC Engineering, Biomedical; Medical Laboratory Technology; Optics SC Engineering; Medical Laboratory Technology; Optics GA BL08J UT WOS:000074223000025 ER PT B AU Doyle, LR Deeg, HJ Jenkins, JM Schneider, J Ninkov, Z Stone, R Gotzger, H Friedman, B Blue, JE Doyle, MF AF Doyle, LR Deeg, HJ Jenkins, JM Schneider, J Ninkov, Z Stone, R Gotzger, H Friedman, B Blue, JE Doyle, MF BE Rebolo, R Martin, EL Osorio, MRZ TI Detectability of Jupiter-to-Brown-Dwarf-mass companions around small eclipsing binary systems SO BROWN DWARFS AND EXTRASOLAR PLANETS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Brown Dwarfs and Extrasolar Planets CY MAR 17-21, 1997 CL PUERTO LA CRUZ, SPAIN SP European Union, Ist Astrofis Canarias, Spanish Min Educ & Culture, Gen Directorate Higher Educ AB The presence of a third body orbiting an eclipsing binary system has long been known to offset the system about a binary/third-body barycenter causing periodic variations in the time of eclipses (due to the increasing or decreasing light traveltime), Recent increased precision in the timing of eclipse minima should allow a survey of the prevalence of Jupiter to Brown Dwarf mass objects by this method using Im-crass telescopes achieving moderately good photometric precision (i.e. 1% or better) with temporal resolution on the order of seconds. Perhaps over 250 such small-mass eclipsing binaries may be successfully surveyed for evidence of such third, outer-orbiting giant planets or brown dwarfs. We discuss the photometric and timing precision required to measure such changes, along with complicating factors that might affect the measured eclipse times of a current program to survey about one dozen binary systems with this method. The importance of such determinations to our general understanding of the formation of solar systems around binary stars is then pointed out. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Doyle, LR (reprint author), NASA, Ames Res Ctr, SETI Inst, MS 245-3, Moffett Field, CA 94035 USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-54-6 J9 ASTR SOC P PY 1998 VL 134 BP 224 EP 231 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK82B UT WOS:000073481100032 ER PT B AU Guirado, JC Reynolds, JE Lestrade, JF Preston, RA Jauncey, DL Jones, DL Tzioumis, AK Ferris, RH King, EA Lovell, JEJ McCulloch, PM Johnston, KJ Kingham, KA Martin, JO White, GL Jones, PA Arenou, F Froeschle, M Kovalevsky, J Martin, C Lindegren, L Soderhjelm, S AF Guirado, JC Reynolds, JE Lestrade, JF Preston, RA Jauncey, DL Jones, DL Tzioumis, AK Ferris, RH King, EA Lovell, JEJ McCulloch, PM Johnston, KJ Kingham, KA Martin, JO White, GL Jones, PA Arenou, F Froeschle, M Kovalevsky, J Martin, C Lindegren, L Soderhjelm, S BE Rebolo, R Martin, EL Osorio, MRZ TI Astrometric detection of a very low-mass companion orbiting a late-type radio star SO BROWN DWARFS AND EXTRASOLAR PLANETS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Brown Dwarfs and Extrasolar Planets CY MAR 17-21, 1997 CL PUERTO LA CRUZ, SPAIN SP European Union, Ist Astrofis Canarias, Spanish Min Educ & Culture, Gen Directorate Higher Educ AB From the combination of VLBI (Very Long Baseline Interferometry) phase-referenced observations and Hipparcos satellite data, we have found evidence of a very low mass object orbiting the late-type star AB Doradus. The mass of the companion inferred from the observed orbital motion places this object on the boundary between a brown dwarf and a very low-mass star. This represents the first detection of a low-mass stellar companion using the VLBI technique, which could become an important tool in future searches for planets and brown dwarfs orbiting other stars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Guirado, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI King, Edward/A-1473-2012; Arenou, Frederic/B-1846-2014 OI King, Edward/0000-0002-6898-2130; Arenou, Frederic/0000-0003-2837-3899 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-54-6 J9 ASTR SOC P PY 1998 VL 134 BP 304 EP 307 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK82B UT WOS:000073481100046 ER PT B AU Warren, WH Dickel, HR AF Warren, WH Dickel, HR BE Rebolo, R Martin, EL Osorio, MRZ TI Nomenclature for extrasolar substellar objects: A new challenge SO BROWN DWARFS AND EXTRASOLAR PLANETS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Brown Dwarfs and Extrasolar Planets CY MAR 17-21, 1997 CL PUERTO LA CRUZ, SPAIN SP European Union, Ist Astrofis Canarias, Spanish Min Educ & Culture, Gen Directorate Higher Educ AB The recent discoveries of extrasolar substellar objects pose additional complications for a nomenclature system (for multiple stars) that is already not entirely consistent. The current situation will probably become even more serious with the inevitable eventual discovery of planetary satellites outside the Solar System. This paper reviews the current system for double and multiple stars, discusses several suggestions already made for designating substellar objects, and proposes adoption of an internally consistent, straightforward system. C1 NASA, Goddard Space Flight Ctr, Hughes STX Corp, Greenbelt, MD 20771 USA. RP Warren, WH (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX Corp, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-54-6 J9 ASTR SOC P PY 1998 VL 134 BP 327 EP 331 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK82B UT WOS:000073481100052 ER PT B AU Rothschild, LJ Grimmer, KF AF Rothschild, LJ Grimmer, KF BE Magoon, OT Converse, H Baird, B MillerHenson, M TI Annual variation in effects of UV radiation on plankton SO CALIFORNIA AND THE WORLD OCEAN '97 - TAKING A LOOK AT CALIFORNIA'S OCEAN RESOURCES: AN AGENDA FOR THE FUTURE, VOLS 1 AND 2, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT California and the World Ocean 97 Conference on Taking a Look at Californias Ocean Resources - An Agenda for the Future CY MAR 24-27, 1997 CL SAN DIEGO, CA AB Environmental effects on coastal communities, especially when they can be monitored remotely, are a critical component of NASA's Mission to Planet Earth. Some environmental variables that have a profound biological effect are changing: for example, surficial fluxes of UVB radiation are rising. What is not known for aquatic systems is the natural annual variability in the effect of UV radiation on plankton. An exciting opportunity to obtain these data has recently become available. The Marine Sciences Institute (MSI) of Redwood City, a science educational organization that runs educational cruises for teachers and students, has begun a collaboration with NASA/Ames to monitor annual variability in UV radiation and its effect on the biota of the San Francisco Bay Estuary. The students and teachers at MSI obtain weekly samples of surface water, make basic physical and chemical measurements of key environmental parameters, acid survey fish. High school and college students based at NASA/Ames collect the samples from MSI and take them to NASA for analysis of UV-absorbing pigments and biomass. We have hypothesized that phytoplankton will produce UV-absorbing pigments in direct response to surficial fluxes of UV radiation, and the early results appear to support the hypothesis. Additional components will be added to this project in the coming year, including analyses of UV-induced DNA damage in the plankton and the acquisition of remotely-sensed data. The educational value of this work will be enhanced through the formation of a Web Site with some data along with information from NASA researchers to assist participating students and teachers in analyzing and interpreting their data, and anyone worldwide in using this study as a classroom exercise. The total data set will be published in the scientific literature. The result will be a critical environmental study on annual variation within this important aquatic community that could not be done without the student contribution. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Rothschild, LJ (reprint author), NASA, Ames Res Ctr, MS 239-12, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0297-3 PY 1998 BP 709 EP 718 PG 4 WC Engineering, Marine; Environmental Sciences; Oceanography; Remote Sensing; Water Resources SC Engineering; Environmental Sciences & Ecology; Oceanography; Remote Sensing; Water Resources GA BL35F UT WOS:000075224700096 ER PT B AU Rothschild, LJ AF Rothschild, LJ BE Magoon, OT Converse, H Baird, B MillerHenson, M TI Will global change affect planktonic productivity? SO CALIFORNIA AND THE WORLD OCEAN '97 - TAKING A LOOK AT CALIFORNIA'S OCEAN RESOURCES: AN AGENDA FOR THE FUTURE, VOLS 1 AND 2, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT California and the World Ocean 97 Conference on Taking a Look at Californias Ocean Resources - An Agenda for the Future CY MAR 24-27, 1997 CL SAN DIEGO, CA AB Phytoplankton are a major source of marine primary productivity. Factors that control algal productivity range from the physical to the chemical to the biological. Currently, levels of atmospheric carbon dioxide and surficial fluxes of ultraviolet radiation are rising. Both of these environmental variables can have a profound effect on algal productivity. Atmospheric CO2 may increase levels of dissolved inorganic carbon in the ocean surface. Laboratory and field studies of algal mats and phytoplankton cultures under ambient and elevated levels of pCO(2) show that elevated levels of inorganic carbon can cause an increase in photosynthetic rates. The increase in photosynthetic rates can result in higher population density. There may be an increase in the excretion of fixed carbon, which in turn may enhance bacterial productivity. Alternatively, in analogy with studies on the effect of elevated pCO2 on plants, the phytoplankton could change their carbon to nitrogen ratios, which will affect the feeding of the planktonic grazers. The seasonal depletion of stratospheric ozone has resulted in elevated fluxes of UVB radiation superimposed on the normal seasonal variation. Present surface UV fluxes have a significant direct impact on algal photosynthesis, as well as indirect effects on cell physiology and aquatic chemistry. While not disputing the importance of other factors in controlling marine, phytoplankton productivity, it is argued here that the global change variables of elevated pCO(2) and UVB radiation should not be ignored. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Rothschild, LJ (reprint author), NASA, Ames Res Ctr, MS 239-12, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0297-3 PY 1998 BP 1563 EP 1575 PG 3 WC Engineering, Marine; Environmental Sciences; Oceanography; Remote Sensing; Water Resources SC Engineering; Environmental Sciences & Ecology; Oceanography; Remote Sensing; Water Resources GA BL35F UT WOS:000075224700210 ER PT B AU Howe, JT Rothschild, LJ AF Howe, JT Rothschild, LJ BE Magoon, OT Converse, H Baird, B MillerHenson, M TI Bio-enrichment by ocean upwelling along the west coast of North America SO CALIFORNIA AND THE WORLD OCEAN '97 - TAKING A LOOK AT CALIFORNIA'S OCEAN RESOURCES: AN AGENDA FOR THE FUTURE, VOLS 1 AND 2, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT California and the World Ocean 97 Conference on Taking a Look at Californias Ocean Resources - An Agenda for the Future CY MAR 24-27, 1997 CL SAN DIEGO, CA AB Primary biological productivity in the coastal ocean is affected by physical oceanography, which in turn is coupled to weather; particularly wind stress, solar heating, and illumination related to photosynthesis. In this paper we begin to put these phenomena together to examine their interrelationships and to estimate the extent to which upwelling enhances productivity along that part of the west coast of North America where it is prominent for a season. Accordingly, the long-term temporal and spatial features of upwelling in ocean waters along the west coast are summarized. In regions of particularly strong upwelling, illustrative ocean observations, measurements, and computations are performed at selected locations spanning more than a decade in time. Results are compared with the results of other studies. Upwelling is shown to enrich biomass as much as fiftyfold. An analytic solution to an approximate set of the rigorous coupled hydrodynamic, energy, radiative transfer, and species conservation equations is presented and described. This includes the effects of weather, wind induced shear stress and its variation (which affect the upwelling formation), illumination (which affects the production of a biomass in surface waters), solar heating, and other physical, chemical, photochemical, and biological events in coastal waters. An approximate analogy (or index) which relates local sea surface temperature and primary productivity parameters in the upwelling formation is discussed. Computed results are compared to NOAA coastal ocean observations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Howe, JT (reprint author), NASA, Ames Res Ctr, Mail Stop 233-20, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0297-3 PY 1998 BP 1577 EP 1594 PG 4 WC Engineering, Marine; Environmental Sciences; Oceanography; Remote Sensing; Water Resources SC Engineering; Environmental Sciences & Ecology; Oceanography; Remote Sensing; Water Resources GA BL35F UT WOS:000075224700212 ER PT J AU Temkin, A Wang, YD Bhatia, AK Sullivan, EC AF Temkin, A Wang, YD Bhatia, AK Sullivan, EC TI The spherically symmetric model of e-H scattering SO CANADIAN JOURNAL OF PHYSICS LA English DT Article ID ELECTRON-HYDROGEN SCATTERING; CROSS-SECTIONS; IONIZATION AB The spherically symmetric model (SSM) for electron-hydrogen scattering is one in which the Coulomb repulsion between the electrons, 2/r(12), is replaced by 2/r(>), where r(>) is the greater of r(1) or r(2). The partial wave decomposition of the wave function for this model is carried out with emphasis on L > 0 partial waves, in which case it is shown that singlet and triplet results are identical. The model, nevertheless, retains all inelastic and ionization channels, and therefore provides a nontrivial testing ground for methods of calculation. The decomposition results in two-dimensional partial differential equations (PDEs). Here numerical calculations are carried out in two ways using (i) a propagation method, and (ii) a noniterative PDE method. The latter is augmented by an integral formula, which greatly enhances the practicality of the method. Elastic phase shifts for L = 1, 2, 3 partial waves in the elastic region are presented. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. RP Temkin, A (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 25 TC 2 Z9 2 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD JAN PY 1998 VL 76 IS 1 BP 23 EP 30 DI 10.1139/cjp-76-1-23 PG 8 WC Physics, Multidisciplinary SC Physics GA YU604 UT WOS:000071734700002 ER PT J AU Savary, CA Grazziutti, ML Melichar, B Przepiorka, D Freedman, RS Cowart, RE Cohen, DM Anaissie, EJ Woodside, DG McIntyre, BW Pierson, DL Pellis, NR Rex, JH AF Savary, CA Grazziutti, ML Melichar, B Przepiorka, D Freedman, RS Cowart, RE Cohen, DM Anaissie, EJ Woodside, DG McIntyre, BW Pierson, DL Pellis, NR Rex, JH TI Multidimensional flow-cytometric analysis of dendritic cells in peripheral blood of normal donors and cancer patients SO CANCER IMMUNOLOGY IMMUNOTHERAPY LA English DT Article DE dendritic cells; flow cytometry; stem cell transplantation; breast cancer ID TUMOR-NECROSIS-FACTOR; MATURE; ALPHA; DIFFERENTIATE; PROGENITORS; ANTIGEN AB We studied the potential of multidimensional flow cytometry to evaluate the frequency and maturation/activation status of dendritic cells in minimally manipulated peripheral blood mononuclear cell preparations (i.e., only separated on Ficoll-Hypaque) of normal donors and cancer patients. A rare subset of HLA-DR+ leukocytes (less than 1% mononuclear cells) was detected in blood of normal donors that displayed all the features of dendritic cells: these cells had high forward-light-scatter characteristics and coexpressed CD4, CD86 and CD54 surface antigens, but lacked the Lineage-associated surface markers of T cells, B cells, monocytes, granulocytes or NK i.e. they were CD3(-), CD19(-), CD20(-), CD14(-), CD11b(-), CD16(-), CD56(-)). These physical and phenotypic properties were virtually identical to those of immunomagnetically sorted leukocytes characterized as dendritic-cells on the basis of morphology, phenotype and high stimulatory activity in allogeneic mixed-lymphocyte cultures. Using this flow-cytometric approach we observed that the frequency of dendritic cell-like cells in peripheral blood mononuclear cell specimens of cancer patients receiving chemotherapy alone or those recovering from stem cell transplantation was significantly lower than that of normal individuals (mean +/- SE: 0.36 +/- 0.05%, 0.14 +/- 0.06%, and 0.75 +/- 0.04% respectively). Multidimensional flow-cytometric analysis of dendritic cells might represent an important new tool for assessing immunocompetence, and for monitoring the effects of therapeutic regimens on the immune system. C1 Univ Texas, Md Anderson Canc Ctr, Dept Surg Oncol, Houston, TX 77030 USA. Univ Texas, Sch Med, Dept Internal Med, Div Infect Dis,Ctr Study Emerging & Reemerging Pa, Houston, TX 77030 USA. Univ Texas, Md Anderson Canc Ctr, Dept Med Specialties, Houston, TX 77030 USA. Univ Texas, Md Anderson Canc Ctr, Dept Gynecol Oncol, Houston, TX 77030 USA. Univ Texas, Md Anderson Canc Ctr, Dept Hematol, Houston, TX 77030 USA. Univ Texas, Md Anderson Canc Ctr, Dept Immunol, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Savary, CA (reprint author), Univ Texas, Md Anderson Canc Ctr, Dept Surg Oncol, 1515 Holcombe Blvd,Box 018, Houston, TX 77030 USA. NR 21 TC 51 Z9 53 U1 1 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-7004 J9 CANCER IMMUNOL IMMUN JI Cancer Immunol. Immunother. PD JAN PY 1998 VL 45 IS 5 BP 234 EP 240 DI 10.1007/s002620050438 PG 7 WC Oncology; Immunology SC Oncology; Immunology GA YN169 UT WOS:000071140000003 PM 9439646 ER PT B AU Yang, CY AF Yang, CY BE Hunter, G Jeffers, S Vigier, JP TI Spacetime invariance and scale effect SO CAUSALITY AND LOCALITY IN MODERN PHYSICS SE FUNDAMENTAL THEORIES OF PHYSICS LA English DT Proceedings Paper CT Symposium on Causality and Locality in Modern Physics and Astronomy - Open Questions and Possible Solutions CY AUG 25-29, 1997 CL YORK UNIV, TORONTO, CANADA SP Senate Ad Hoc Funding Comm York Univ HO YORK UNIV AB A logic of reciprocity between inertial frames in relative uniform motion is investigated. Relativity allows any reference frame to apply Lorentz Transformation while reciprocity would require the relative frame to use Inverse Transformation for the same event, and vice versa. After such transformations, an inseparability between relativistic measurements and the covariant scale is examined. Scale conversion has been found to be necessary to preserve spacetime invariance in Special Relativity. A new derivation of the Lorentz Factor has been found based on the scale effect. The physical meaning of the Factor is that it serves as a scale conversion ratio between relative reference frames. Reciprocity in relativity and causality of covariance in relative motion are thereby conserved. These logical conclusions harmonize intrinsic natural invariances vis-avis apparent observational covariances. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yang, CY (reprint author), NASA, Goddard Space Flight Ctr, Code 2501, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5227-0 J9 FUND THEOR PY 1998 VL 97 BP 253 EP 259 PG 3 WC Astronomy & Astrophysics; Optics; Physics, Multidisciplinary; Physics, Particles & Fields; Physics, Mathematical SC Astronomy & Astrophysics; Optics; Physics GA BM07A UT WOS:000077539100030 ER PT B AU Levit, C Sarfatti, J AF Levit, C Sarfatti, J BE Hunter, G Jeffers, S Vigier, JP TI Are the Bader Laplacian and the Bohm quantum potential equivalent? SO CAUSALITY AND LOCALITY IN MODERN PHYSICS SE FUNDAMENTAL THEORIES OF PHYSICS LA English DT Proceedings Paper CT Symposium on Causality and Locality in Modern Physics and Astronomy - Open Questions and Possible Solutions CY AUG 25-29, 1997 CL YORK UNIV, TORONTO, CANADA SP Senate Ad Hoc Funding Comm York Univ HO YORK UNIV C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Levit, C (reprint author), NASA, Ames Res Ctr, MS T27A, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5227-0 J9 FUND THEOR PY 1998 VL 97 BP 353 EP 358 PG 4 WC Astronomy & Astrophysics; Optics; Physics, Multidisciplinary; Physics, Particles & Fields; Physics, Mathematical SC Astronomy & Astrophysics; Optics; Physics GA BM07A UT WOS:000077539100041 ER PT B AU Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T AF Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T BE Sofue, Y TI 4.5 to 11.7 microns spectrophotometric observations of the Galactic bulge by the MIRS/IRTS SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chan, KW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 47 EP 47 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500017 ER PT B AU Ptak, A Serlemitsos, P Yaqoob, T Mushotzky, R Terashima, Y Kunieda, H AF Ptak, A Serlemitsos, P Yaqoob, T Mushotzky, R Terashima, Y Kunieda, H BE Sofue, Y TI X-ray constraints on accretion and starburst processes in galactic nuclei SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ptak, A (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 109 EP 110 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500045 ER PT B AU Gezari, D AF Gezari, D BE Sofue, Y TI SGR A* in the mid-infrared reference frame - No evidence of an infrared counterpart, or interaction with nearby sources SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gezari, D (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 295 EP 297 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500121 ER PT B AU Chan, KW Moseley, SH Dwek, E Roellig, TL Casey, S Loewenstein, R AF Chan, KW Moseley, SH Dwek, E Roellig, TL Casey, S Loewenstein, R BE Sofue, Y TI Tentative detection of far infrared excess in Arp 220 SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union AB We report 36 to 50 mu m observations of Arp 220 by the Goddard Cryogenic Grating Spectrometer on the Kuiper Airborne Observatory in May 1994. In this measurement, we find the galaxy to be four times brighter than in the measurements of Joy et al. (1986). If both of the observations are correct, this large far infrared luminosity increasing in a short time scale between the two observations suggests that the infrared emission in Arp 220 consists mostly of nonthermal synchrotron radiation which originates from the active nucleus. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chan, KW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 301 EP 302 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500123 ER PT B AU Chan, KW Moseley, SH Casey, S Harrington, JP Dwek, E Loewenstein, R Varosi, F Glaccum, W AF Chan, KW Moseley, SH Casey, S Harrington, JP Dwek, E Loewenstein, R Varosi, F Glaccum, W BE Sofue, Y TI Dust composition, energetics, and morphology of the Galactic center SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chan, KW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 303 EP 304 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500124 ER PT B AU Cotera, AS Werner, MW Plavchan, PP AF Cotera, AS Werner, MW Plavchan, PP BE Sofue, Y TI Confirmation of a MIR source near SGR A* SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union ID GALAXY C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cotera, AS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 311 EP 312 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500128 ER PT B AU Jones, DL Wehrle, AE AF Jones, DL Wehrle, AE BE Sofue, Y TI A sub-parsec accretion disk in NGC 4261 SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union ID NGC-4261 AB We observed the nuclear region of NGC 4261 (3C270) with the VLBA to determine the morphology of the central radio source on parsec scales. Our highest angular resolution image at 8.4 GHz shows a very narrow gap in emission just east of the radio core (on the counterjet side), which we interpret as an absorption feature caused by a small, dense inner accretion disk whose width is less than 0.1 parsec. If the inclination of this inner disk is close to that of the much larger-scale disk imaged by HST, it becomes optically thin to 8.4 GHz radiation at a deprojected radius of about 0.8 pc. September 1997 VLBA observations at higher frequencies should allow us to determine the radial electron density distribution of the inner disk. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, Mail Code 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 413 EP 414 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500165 ER PT B AU Meier, DL Godon, P Edgington, S Payne, DG Lind, KR AF Meier, DL Godon, P Edgington, S Payne, DG Lind, KR BE Sofue, Y TI The magnetic switch and the FR I FR II break SO CENTRAL REGIONS OF THE GALAXY AND GALAXIES LA English DT Proceedings Paper CT 184th Symposium of the International-Astronomical-Union CY AUG 18-22, 1997 CL TOKYO, JAPAN SP Int Astronom Union ID BLACK-HOLES; SCALE JETS; RADIO AB It is proposed that the Fanaroff and Riley division between class I and class II radio sources may he due to phenomena occurring in the coronae of magnetized accretion disks around black holes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-5060-X PY 1998 BP 491 EP 492 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM57Y UT WOS:000079158500194 ER PT B AU DiCarlo, JA Yun, HM AF DiCarlo, JA Yun, HM BE Takeda, N Sheppard, LM Kon, J TI Microstructural factors affecting creep-rupture failure of ceramic fibers and composites SO CERAMIC MATERIAL SYSTEMS WITH COMPOSITE STRUCTURES: TOWARDS OPTIMUM INTERFACE CONTROL AND DESIGN LA English DT Proceedings Paper CT Japan-Fine-Ceramics-Center International Workshop in Fine Ceramics 98 CY MAR 12-13, 1998 CL NAGOYA, JAPAN SP Japan Fine Ceram Ctr, Japan Keirin Assoc AB Using measurements of the tensile creep-rupture behavior of continuous-length alumina- and SiC-based fibers, this study examines the manner in which these results are affected by such key fiber microstructural factors as chemical composition, grain size, and impurity characteristics. It is shown that under test conditions representative of potential service in ceramic composites, the creep data of these fine-grained fibers display dependencies on stress and grain size which can be explained well by the mechanism of interface-controlled diffusional creep. Assuming this to be the case, analytical models are developed which can be used for understanding and predicting the effects of the key microstructural factors as well as application conditions on such technically important fiber properties as creep strength and rupture strength. To understand whether the microstructures of currently available fibers should be improved further, the rupture strength model is used to construct thermostructural performance maps for ceramic matrix composites reinforced with the most creep-resistant fibers of different compositions. These time-temperature-stress-dependent maps suggest that the microstructures of available alumina-based fibers cannot provide composite performance competitive with the best nickel-based superalloys. On the other hand, the microstructures of available SiC-based fibers should yield composites with sufficient performance. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP DiCarlo, JA (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA BN 1-57498-065-3 PY 1998 BP 119 EP 134 PG 16 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BL99W UT WOS:000077407200011 ER PT S AU Siskind, DE Barth, CA Russell, JM AF Siskind, DE Barth, CA Russell, JM BE Rees, D TI A climatology of nitric oxide in the mesosphere and thermosphere SO CIRA PART III REFERENCE ATMOSPHERES - TRACE CONSTITUENT MODELS - COMPARISON WITH LATEST DATA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C4 3 Symposium of the COSPAR Scientific Commission C on CIRA Part III Reference Atmospheres : Trace Constituent Models - Comparison with Latest Data at the 31st COSPAR CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Sci Comm Solar Terr Phys ID AURORAL STORM; LATITUDES; MIDDLE AB Global measurements of nitric oxide (NO) in the earth's upper atmosphere have now been obtained by two satellite experiments during the declining phases of the last two solar cycles. In the 1980's, NO was measured by the Solar Mesosphere Explorer while in the 1990's, NO has been observed by the Halogen Occultation Experiment (HALOE) on board the UARS satellite. The SME data cover the altitude range from 95 to 160 km and extend from pole to pole. The HALOE data used here cover the altitude range from 50 to 125 km and extend from 70N to 70S. Both datasets show a well defined decrease in NO during the decline of solar activity. Also, large perturbations due to auroral activity are seen at middle and high latitudes. In addition, the HALOE data show large increases in the high latitude winter mesosphere which are associated with downward transport from the thermosphere. This paper presents a reference NO model which is based upon the two datasets and which covers a wide range of solar, geomagnetic and seasonal conditions. Published by Elsevier Science Ltd on behalf of COSPAR. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Siskind, DE (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NR 13 TC 37 Z9 37 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043463-0 J9 ADV SPACE RES PY 1998 VL 21 IS 10 BP 1353 EP 1362 DI 10.1016/S0273-1177(97)00743-6 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL14H UT WOS:000074437400001 ER PT S AU Waters, JW AF Waters, JW BE Rees, D TI Atmospheric measurements by the MLS experiments: Results from UARS and plans for the future SO CIRA PART III REFERENCE ATMOSPHERES - TRACE CONSTITUENT MODELS - COMPARISON WITH LATEST DATA SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Review CT C4 3 Symposium of the COSPAR Scientific Commission C on CIRA Part III Reference Atmospheres : Trace Constituent Models - Comparison with Latest Data at the 31st COSPAR CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Sci Comm Solar Terr Phys ID MICROWAVE LIMB SOUNDER; TROPOSPHERIC WATER-VAPOR; POLAR VORTEX CONDITIONS; RESEARCH SATELLITE UARS; ARCTIC OZONE DEPLETION; SOUTHERN-HEMISPHERE; STRATOSPHERIC CLO; INTERHEMISPHERIC DIFFERENCES; TEMPERATURE-MEASUREMENTS; EARLY WINTER AB The Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) has provided measurements of O(3), H(2)O, ClO, SO(2), HNO(3), temperature and pressure in Earth's atmosphere. These measurements, which have been used for a variety of scientific studies, are obtained near-globally both day and night, and are made reliably even in the presence of aerosols, cirrus or polar stratospheric clouds. MLS experiments now being developed for the NASA Earth Observing System (EOS) and the future use new technology for measurements of additional trace species and improved global coverage. Published by Elsevier Science Ltd on behalf of COSPAR. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Waters, JW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 108 TC 9 Z9 9 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043463-0 J9 ADV SPACE RES-SERIES PY 1998 VL 21 IS 10 BP 1363 EP 1372 DI 10.1016/S0273-1177(97)00744-8 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL14H UT WOS:000074437400002 ER PT S AU Ansari, RR Suh, KI AF Ansari, RR Suh, KI BE Tuchin, VV Izatt, JA Katzir, A TI Dynamic light scattering particle size measurements in turbid media SO COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICAL SCIENCE AND CLINICAL APPLICATIONS II, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Coherence Domain Optical Methods in Biomedical Science and Clinical Applications II CY JAN 27-28, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers, Int Biomed Opt Soc AB Dynamic light scattering (DLS) particle size measurements are reported for turbid systems. These include particulate dispersions and suspensions of macromolecules in a wide (7 nm-800 nm) particle size (diameter) range which look as transparent as water and as turbid as milk (turbidity similar to 6-7 orders of magnitude higher than water) and samples of lenticular and skin tissues. Our results indicate a significant improvement in achieving non-invasive, compact, robust, and remotely operated DLS probes which are able to push the envelope of DLS utilization to extremely turbid samples of a variety of particle type and size of macromolecules which were hitherto not possible. C1 NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids Combust Sci, Cleveland, OH 44135 USA. RP Ansari, RR (reprint author), NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids Combust Sci, 21000 Brookpk Rd,Mail Stop 333-1, Cleveland, OH 44135 USA. NR 0 TC 7 Z9 7 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2690-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3251 BP 146 EP 156 DI 10.1117/12.306048 PG 11 WC Engineering, Biomedical; Medical Laboratory Technology; Optics; Statistics & Probability SC Engineering; Medical Laboratory Technology; Optics; Mathematics GA BL08H UT WOS:000074222900017 ER PT J AU Rhatigan, JL Bedir, H Tien, JS AF Rhatigan, JL Bedir, H Tien, JS TI Gas-phase radiative effects on the burning and extinction of a solid fuel SO COMBUSTION AND FLAME LA English DT Article ID DIFFUSION FLAMES AB Gas-phase radiative effects on the burning and extinction of a solid fuel in a stagnation-point flow geometry are investigated using a statistical narrow-band model with carbon dioxide and water vapor as the radiative participating media. The model, coupled to other flame conservation equations with a one-step overall gas-phase chemical reaction and Arrhenius solid pyrolysis relation, is solved numerically. Flame temperature, solid burning rate, and heat fluxes are examined as functions of stretch rate. Using ambient oxygen percentage and stretch rate as coordinates, a U-shaped extinction boundary is identified. The extinction behavior at low stretch rates is qualitatively similar to that predicted by earlier theory with only surface radiation loss. However, gas radiation introduces additional heat loss from the system and shrinks the solid flammable domain. In addition, gas radiation can cause a substantial decrease of flame temperature and constitutes a significant portion of the heat feedback to the solid at low stretch rates. In the second part of the paper, a computationally less intensive gray gas radiation model is tested. As with a number of earlier investigations, the use of Planck mean absorption coefficient is found to overpredict net emission and flame radiative loss. By multiplying a correction factor (less than 1) in front of the Planck mean absorption coefficient, it is possible to compute many global flame properties with reasonable accuracy. An empirically determined formula is given to find the value of this correction factor for a given flame. This is offered as an engineering approach for the flame radiation treatment. (C) 1998 by The Combustion Institute. C1 CASE WESTERN RESERVE UNIV,DEPT MECH & AEROSP ENGN,CLEVELAND,OH 44106. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 37 TC 33 Z9 34 U1 2 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JAN PY 1998 VL 112 IS 1-2 BP 231 EP 241 DI 10.1016/S0010-2180(97)81771-3 PG 11 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA YH962 UT WOS:A1998YH96200019 ER PT J AU Price, EW Chakravarthy, SR Sambamurthi, JK Sigman, RK AF Price, EW Chakravarthy, SR Sambamurthi, JK Sigman, RK TI The details of combustion of ammonium perchlorate propellants: Leading edge flame detachment SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE solid propellant combustion; laminar premixed-to-diffusion flamelet transition ID COMPOSITE SOLID-PROPELLANTS; DIFFUSION AB The transition from particle flamelet burning to premixed flame burning of ammonium perchlorate (AP)/hydrocarbon (HC) binder propellants is identified with detachment of the oxidizer/fuel (O/F) flamelet from the stoichiometric Lip of the diffusion field over the AP particle. The conditions (pressure, particle area, local stoichiometry) for detachment are revealed by singular regions of the burning rate versus pressure curves for selected bimodal propellants. C1 Georgia Inst Technol, Sch Aerosp Engn, Atlanta, GA 30332 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Chakravarthy, SR (reprint author), Indian Inst Technol, Dept Aerosp Engn, Madras 600036, Tamil Nadu, India. NR 25 TC 10 Z9 10 U1 2 U2 7 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1998 VL 138 IS 1-6 BP 63 EP 83 DI 10.1080/00102209808952063 PG 21 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 156XM UT WOS:000078027800004 ER PT J AU Locke, RJ Hicks, YR Anderson, RC Zaller, MM AF Locke, RJ Hicks, YR Anderson, RC Zaller, MM TI Optical fuel injector patternation measurements in advanced liquid-fueled, high pressure, gas turbine combustors SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE nonintrusive optical diagnostics; planar laser-induced fluorescence; spray patternation ID LASER-INDUCED FLUORESCENCE; FLAMES; NO AB Planar laser-induced fluorescence (PLIF) imaging and planar Mie scattering are used to examine the fuel distribution pattern (patternation) for advanced fuel injector concepts in kerosene burning, high pressure gas turbine combustors. Three fuel injector concepts for aerospace applications were investigated under a broad range of operating conditions. Planar fuel PLIF patternation results are contrasted with those obtained by planar Mie scattering. For one injector, further comparison is also made with data obtained through phase Doppler measurements. Differences in spray patterns for diverse conditions and fuel injector configurations are readily discernible. An examination of the data has shown that a direct determination of the fuel spray angle at realistic conditions is also possible. The results obtained in this study demonstrate the applicability and usefulness of these nonintrusive optical techniques for investigating fuel spray patternation under actual combustor conditions. C1 Dynacs Engn Co, Aeropropuls Syst Dept, Brook Pk, OH 44142 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Locke, RJ (reprint author), Dynacs Engn Co, Aeropropuls Syst Dept, 2001 Aerosp Pkwy, Brook Pk, OH 44142 USA. NR 17 TC 12 Z9 14 U1 0 U2 5 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1998 VL 138 IS 1-6 BP 297 EP + DI 10.1080/00102209808952073 PG 19 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 156XM UT WOS:000078027800014 ER PT J AU Vander Wal, RL AF Vander Wal, RL TI An illustration of soot structure by dark field transmission electron microscopy SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE soot; carbon; combustion; transmission electron microscopy AB Bright and dark field TEM images are presented for soot emitted from an acetylene gas-jet diffusion flame. The relative spatial distribution of the dark held TEM image intensities is interpreted in relation to the soot particle structure and diffraction from crystallographic layer planes as understood from studies of carbon blacks. C1 NASA, Lewis Res Ctr, NCMR, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA, Lewis Res Ctr, NCMR, MS 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 13 TC 8 Z9 8 U1 1 U2 4 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1998 VL 132 IS 1-6 BP 315 EP 323 DI 10.1080/00102209808952018 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 262XE UT WOS:000084092900011 ER PT S AU O'Brien, TK AF O'Brien, TK BE Bucinell, RB TI Composite interlaminar shear fracture toughness, G(IIc): Shear measurement or sheer myth? SO COMPOSITE MATERIALS: FATIGUE AND FRACTURE, SEVENTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 7th Symposium on Composites - Fatigue and Fracture CY MAY 07-08, 1997 CL ST LOUIS, MO SP ASTM Comm D30 Composite Mat, ASTM Comm E9 Fatigue & Fracture DE fractures toughness; shear; interlaminar fracture toughness; composites ID EPOXY COMPOSITES; DELAMINATION; FAILURE; MECHANISMS AB The concept of G(Ilc) as a measure of the interlaminar shear fracture toughness of a composite material is critically examined. In particular, it is argued that the apparent G(Ilc) as typically measured is inconsistent with the original definition of shear fracture. It is shown that interlaminar shear failure actually consists of tension failures in the resin-rich layers between plies followed by the coalescence of ligaments created by these failures and not the sliding of two planes relative to one another that is assumed in fracture mechanics theory. Several strain energy release rate solutions are reviewed for delamination in composite laminates and structural components where failures have been experimentally documented. Failures typically occur at a location where the Mode I component accounts for at least one half of the total G at failure. Hence, it is the Mode I and mixed-mode interlaminar fracture toughness data that will be most useful in predicting delamination failure in composite components in service. Although apparent G(Ilc) measurements may prove useful for completeness of generating mixed-mode criteria, the accuracy of these measurements may have very little influence on the prediction of mixed-mode failures in most structural components. C1 NASA, Langley Res Ctr, Vehicle Technol Ctr, USA,Res Lab, Hampton, VA 23681 USA. RP O'Brien, TK (reprint author), NASA, Langley Res Ctr, Vehicle Technol Ctr, USA,Res Lab, Hampton, VA 23681 USA. NR 48 TC 50 Z9 50 U1 0 U2 3 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2609-3 J9 AM SOC TEST MATER PY 1998 VL 1330 BP 3 EP 18 DI 10.1520/STP13263S PG 16 WC Mechanics; Materials Science, Composites SC Mechanics; Materials Science GA BM47P UT WOS:000078854000002 ER PT S AU Cvitkovich, MK O'Brien, TK Minguet, PJ AF Cvitkovich, MK O'Brien, TK Minguet, PJ BE Bucinell, RB TI Fatigue debonding characterization in composite skin/stringer configurations SO COMPOSITE MATERIALS: FATIGUE AND FRACTURE, SEVENTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 7th Symposium on Composites - Fatigue and Fracture CY MAY 07-08, 1997 CL ST LOUIS, MO SP ASTM Comm D30 Composite Mat, ASTM Comm E9 Fatigue & Fracture DE composite materials; fatigue testing; design; bond strength; skin/flange interface; secondary bonding AB The objective of this work was to investigate the fatigue damage mechanisms and to identify the influence of skin stacking sequence in carbon epoxy composite bonded skin/stringer constructions. A simple four-point-bending test fixture originally designed for previously performed monotonic tests was used to evaluate the fatigue debonding mechanisms between the skin and the bonded frame when the dominant loading in the skin is flexure along the edge of the frame. The specimens consisted of a tapered flange, representing the stringer, bonded onto a skin. Based on the results of previous monotonic tests, two different skin layups in combination with one flange layup were investigated. The tests were performed at load levels corresponding to 40, 50, 60, 70, and 80% of the monotonic fracture loads. Microscopic investigations of the specimen edges were used to document the onset of matrix cracking and delamination and subsequent fatigue delamination growth. Typical damage patterns for both specimen configurations were identified. The observations showed that failure initiated near the tip of the flange in the form of matrix cracks at one of two locations, one in the skin and one in the flange. The location of the 90 degrees flange and skin plies relative to the bondline was identified as the dominant layup feature that controlled the location and onset of matrix cracking and subsequent delamination. The fatigue delamination growth experiments yielded matrix cracking and delamination onset as a function of fatigue cycles as well as delamination length as a function of the number of cycles. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cvitkovich, MK (reprint author), NASA, Langley Res Ctr, Mail Stop 188E, Hampton, VA 23681 USA. NR 4 TC 9 Z9 9 U1 3 U2 4 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2609-3 J9 AM SOC TEST MATER PY 1998 VL 1330 BP 97 EP 121 DI 10.1520/STP13268S PG 25 WC Mechanics; Materials Science, Composites SC Mechanics; Materials Science GA BM47P UT WOS:000078854000007 ER PT S AU Nettles, AT AF Nettles, AT BE Bucinell, RB TI The effects of tensile preloads on the impact response of carbon/epoxy laminates SO COMPOSITE MATERIALS: FATIGUE AND FRACTURE, SEVENTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 7th Symposium on Composites - Fatigue and Fracture CY MAY 07-08, 1997 CL ST LOUIS, MO SP ASTM Comm D30 Composite Mat, ASTM Comm E9 Fatigue & Fracture DE composites; damage resistance; preload; instrumented impact; toughened epoxy; nondestructive evaluation; delamination ID COMPOSITE AB Low-velocity instrumented dropweight impact tests were performed on carbon/epoxy laminates. The composite plates were 8-ply (+45, 0, -45, 90)(8) laminates supported in a clamped-clamped/free-free configuration with varying amounts of in-plane load N-x, applied. The amount of damage induced into the specimen was evaluated using the instrumented impact data and X-ray inspection. Results showed that for a given impact energy level, more damage was induced into the specimen as the external in-plane load, N-x, was increased. The majority of damage observed consisted of backface splitting of the matrix parallel to the fibers in that ply, associated with delaminations emanating from these splits. A free-edge delamination model was used to explain the type and extent of the major delaminations caused by the preload/impact combinations. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Nettles, AT (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2609-3 J9 AM SOC TEST MATER PY 1998 VL 1330 BP 249 EP 262 DI 10.1520/STP13276S PG 14 WC Mechanics; Materials Science, Composites SC Mechanics; Materials Science GA BM47P UT WOS:000078854000015 ER PT J AU Fergus, JW Mallipedi, CVS Edwards, DL AF Fergus, JW Mallipedi, CVS Edwards, DL TI Silver/silver-oxide composite coating for intrinsically adaptive thermal regulation SO COMPOSITES PART B-ENGINEERING LA English DT Article DE heat transfer; oxidation; adoptive materials ID POLYCRYSTALLINE SILVER FILMS; INDOOR CORROSION; OXIDATION; REDUCTION; OXYGEN; COPPER AB A concept for an automatic thermal regulation system using the changes in surface properties associated with the oxidation of silver and the reduction of silver oxide at a critical temperature has been evaluated. The change in thermal transfer properties between silver and silver oxide are favorable for thermal regulation if the incident radiation is in the infrared range. However, while the reduction of silver oxide occurs rapidly, the oxidation of silver occurs slowly, so a silver/silver-oxide composite coating will not likely produce reversible adaptive thermal regulation. However, thermal regulation at higher temperatures, where the oxidation End reduction reactions are more rapid, may be possible using other materials. The criteria for selection of potential metal/metal-oxide composite coatings for adaptive thermal regulation are discussed. (C) 1997 Published by Elsevier Science Ltd. All rights reserved. C1 Auburn Univ, Mat Res & Educ Ctr, Auburn, AL 36849 USA. NASA, George C Marshall Space Flight Ctr, Div Engn Phys, Huntsville, AL 35812 USA. RP Fergus, JW (reprint author), Auburn Univ, Mat Res & Educ Ctr, 201 Ross Hall, Auburn, AL 36849 USA. OI Fergus, Jeffrey/0000-0002-8067-1992 NR 12 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-8368 J9 COMPOS PART B-ENG JI Compos. Pt. B-Eng. PY 1998 VL 29 IS 1 BP 51 EP 56 DI 10.1016/S1359-8368(97)00010-3 PG 6 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA YP479 UT WOS:000071280900007 ER PT J AU O'Brien, TK AF O'Brien, TK TI Interlaminar fracture toughness: The long and winding road to standardization SO COMPOSITES PART B-ENGINEERING LA English DT Article DE delamination; fracture; toughness ID DELAMINATION TEST; MODE AB The on-going efforts to achieve internationally accepted test standards for interlaminar fracture toughness over the past two decades will be reviewed. The status of current efforts to obtain an ISO standard for the Double Cantilever Beam test for mode I interlaminar fracture toughness will be highlighted. Current round robin activity underway to develop standards for mode II, mode III, and mixed-mode interlaminar fracture toughness will also be discussed. Differences in the interpretation of interlaboratory "round robin" test results will be highlighted. The influence of the different roles of standardization bodies in the US, Europe, and Japan on achieving international standards for interlaminar fracture toughness will be discussed. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Vehicle Technol Ctr, USA,Res Lab, Hampton, VA 23681 USA. RP O'Brien, TK (reprint author), NASA, Langley Res Ctr, Vehicle Technol Ctr, USA,Res Lab, Hampton, VA 23681 USA. NR 16 TC 68 Z9 68 U1 1 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-8368 J9 COMPOS PART B-ENG JI Compos. Pt. B-Eng. PY 1998 VL 29 IS 1 BP 57 EP 62 DI 10.1016/S1359-8368(97)00013-9 PG 6 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA YP479 UT WOS:000071280900008 ER PT J AU Cook, GM Tessler, A AF Cook, GM Tessler, A TI A {3,2}-order bending theory for laminated composite and sandwich beams SO COMPOSITES PART B-ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Mechanics of Composites of the McNU 97 Joint ASME/ASCE/SES Mechanics Conference CY JUN 29-JUL 02, 1997 CL NORTHWESTERN UNIV, EVANSTON, ILLINOIS SP ASME, ASCE, SES HO NORTHWESTERN UNIV ID HIGHER-ORDER THEORY; PLATES; DEFORMATION; SHELLS; SHEAR AB A higher-order bending theory is derived for laminated composite and sandwich beams thus extending the recent {1,2}-order theory to include third-order axial effects without introducing additional kinematic variables. The present theory is of order {3,2} and includes both transverse shear and transverse normal deformations. A closed-form solution to the cylindrical bending problem is derived and compared with the corresponding exact elasticity solution. The numerical comparisons are focused on the most challenging material systems and beam aspect ratios which include moderate-to-thick unsymmetric composite and sandwich laminates. Advantages and Limitations of the theory are discussed. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Struct Div, Langley Res Ctr, Hampton, VA 23681 USA. George Washington Univ, Sch Engn & Appl Sci, Hampton, VA 23681 USA. RP Tessler, A (reprint author), NASA, Struct Div, Langley Res Ctr, Hampton, VA 23681 USA. RI Tessler, Alexander/A-4729-2009 NR 23 TC 37 Z9 38 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-8368 J9 COMPOS PART B-ENG JI Compos. Pt. B-Eng. PY 1998 VL 29 IS 5 BP 565 EP 576 DI 10.1016/S1359-8368(98)00011-0 PG 12 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA 130UC UT WOS:000076537900005 ER PT J AU Gotsis, PK Chamis, CC Minnetyan, L AF Gotsis, PK Chamis, CC Minnetyan, L TI Prediction of composite laminate fracture: Micromechanics and progressive fracture SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE glass fibers; graphite fibers; epoxy matrices; composite properties; failure envelopes; combined loading; residual stress; pristine properties; in situ properties; stress/strain curves; cross-ply laminates; angle-ply laminates; multidirectional laminates AB An investigation is described on the prediction of first-ply failure and fracture in selected composite laminates. The laminates are made from glass fibers and graphite fibers in epoxy matrices. Failure envelopes are generated for combined loading of these laminates on the basis of first-ply failure and laminate fracture. The evaluation is performed by a micromechanics-based theory and progressive fracture. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Clarkson Univ, New York, NY USA. RP Gotsis, PK (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 40 Z9 47 U1 1 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PY 1998 VL 58 IS 7 BP 1137 EP 1149 DI 10.1016/S0266-3538(97)00014-6 PG 13 WC Materials Science, Composites SC Materials Science GA 127GG UT WOS:000076342100013 ER PT S AU Frisch, HP AF Frisch, HP BE Kaynak, O Zadeh, LA Truksen, B Rudas, IJ TI A product life cycle information management system infrastructure with CAD/CAE/CAM, task automation, and intelligent support capabilities SO COMPUTATIONAL INTELLIGENCE: SOFT COMPUTING AND FUZZY-NEURO INTEGRATION WITH APPLICATIONS SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES F, COMPUTER AND SYSTEMS SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Soft Computing and Its Applications CY AUG 21-31, 1996 CL MANAVGAT, TURKEY SP NATO AB NASA is not unique in its quest for a product development cycle that is better, faster, and cheaper. Major advances in technical information management will be required to achieve significant and obvious process improvement goals. A vision of order for the associated systems of unstructured and unconnected files and databases is the first step towards organization. This is provided by examining the basic nature of technical information, item relationships, change and knowledge processing demands to be placed on any management system that supports all aspects of data representation and exchange during the product's full propose, design, develop and deploy life cycle. An infrastructure that partitions product technical information relative to the perspectives of creation time phase, type and the cause of change provides sufficient structure. This enables maximal use of existing CAD/CAE/CAM/... software tool systems and digital library data mining capabilities. Introducing the concept of packaging technical information in a machine interpretable manner, at key life cycle deliverable and product review milestone points, provides the fastener needed for the attachment of the relevant soft computing and intelligent support capabilities discussed at the NATO Advanced Study Institute on Soft Computing and reported elsewhere within this volume. It also provides the basis upon which task automation capabilities can evolve. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Frisch, HP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0258-1248 BN 3-540-64004-5 J9 NATO ADV SCI I F-COM PY 1998 VL 162 BP 521 EP 538 PG 18 WC Computer Science, Artificial Intelligence; Engineering, Industrial SC Computer Science; Engineering GA BM48P UT WOS:000078876900026 ER PT B AU Arian, E AF Arian, E BE Borggaard, J Burns, J Cliff, E Schreck, S TI MDO - A mathematical view point SO COMPUTATIONAL METHODS FOR OPTIMAL DESIGN AND CONTROL SE PROGRESS IN SYSTEMS AND CONTROL THEORY LA English DT Proceedings Paper CT 2nd International Workshop on Optimal Design and Control CY SEP 30-OCT 03, 1997 CL ARLINGTON, VA SP USAF, Off Sci Res, Virginia Tech, Ctr Optimal Design & Control AB A quantitative analysis of coupling between systems of equations is introduced. This analysis is then applied to problems in multidisciplinary analysis, sensitivity, and optimization. For the sensitivity and optimization problems both multidisciplinary and single discipline feasibility schemes are considered. In all these cases a "convergence factor" is estimated in terms of the Jacobians and hessians of the system, thus it can also be approximated by existing disciplinary analysis and optimization codes. The convergence factor is identified with the measure for the "coupling" between the disciplines in the system. Applications to algorithm development are discussed. Demonstration of the convergence estimates and numerical results are given for a system composed of two non-linear algebraic equations, and for a system composed of two PDEs modeling aeroelasticity. C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP Arian, E (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop 403, Hampton, VA 23681 USA. NR 14 TC 0 Z9 0 U1 0 U2 1 PU BIRKHAUSER BOSTON PI CAMBRIDGE PA 675 MASSACHUSETTS AVE, CAMBRIDGE, MA 02139-2333 USA BN 0-8176-4064-9 J9 PROG SYST C PY 1998 VL 24 BP 27 EP 47 PG 21 WC Automation & Control Systems; Computer Science, Theory & Methods; Engineering, Multidisciplinary; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Mathematics GA BP09P UT WOS:000084108600002 ER PT B AU Lewis, RM AF Lewis, RM BE Borggaard, J Burns, J Cliff, E Schreck, S TI Numerical computation of sensitivities and the adjoint approach SO COMPUTATIONAL METHODS FOR OPTIMAL DESIGN AND CONTROL SE PROGRESS IN SYSTEMS AND CONTROL THEORY LA English DT Proceedings Paper CT 2nd International Workshop on Optimal Design and Control CY SEP 30-OCT 03, 1997 CL ARLINGTON, VA SP USAF, Off Sci Res, Virginia Tech, Ctr Optimal Design & Control ID CONVERGENCE AB We discuss the numerical computation of sensitivities via the adjoint approach in optimization problems governed by differential equations. We focus on the adjoint problem in its weak form. We show how one can avoid some of the problems with the adjoint approach, such as deriving suitable boundary conditions for the adjoint equation. We discuss the convergence of numerical approximations of the costate computed via the weak form of the adjoint problem and show the significance for the discrete adjoint problem. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Lewis, RM (reprint author), NASA, Langley Res Ctr, ICASE, Mail Stop 403, Hampton, VA 23681 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU BIRKHAUSER BOSTON PI CAMBRIDGE PA 675 MASSACHUSETTS AVE, CAMBRIDGE, MA 02139-2333 USA BN 0-8176-4064-9 J9 PROG SYST C PY 1998 VL 24 BP 285 EP 302 PG 18 WC Automation & Control Systems; Computer Science, Theory & Methods; Engineering, Multidisciplinary; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Mathematics GA BP09P UT WOS:000084108600016 ER PT B AU Loncaric, J AF Loncaric, J BE Borggaard, J Burns, J Cliff, E Schreck, S TI Sensor/actuator placement via optimal distributed control of exterior stokes flow SO COMPUTATIONAL METHODS FOR OPTIMAL DESIGN AND CONTROL SE PROGRESS IN SYSTEMS AND CONTROL THEORY LA English DT Proceedings Paper CT 2nd International Workshop on Optimal Design and Control CY SEP 30-OCT 03, 1997 CL ARLINGTON, VA SP USAF, Off Sci Res, Virginia Tech, Ctr Optimal Design & Control ID SYSTEMS AB Effective placement of sensors and actuators is of crucial importance in how control. Instead of using combinatorial search to identify optimal locations, we pose a related problem of polynomial complexity. If one could sense everything and actuate everywhere, what should one do? Using the unsteady 2D Stokes flow around a cylinder as an example, we obtain the analytic solution of an optimal distributed control problem and describe its spatial structure. At low circumferential wavenumbers or close to the cylinder wall, boundary vortex generators are shown to be more effective than collocated vorticity damping. This analytic solution has also been used to test numerical methods, demonstrating the importance of using discretization which resolves all eigen functions of interest. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Loncaric, J (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU BIRKHAUSER BOSTON PI CAMBRIDGE PA 675 MASSACHUSETTS AVE, CAMBRIDGE, MA 02139-2333 USA BN 0-8176-4064-9 J9 PROG SYST C PY 1998 VL 24 BP 303 EP 322 PG 20 WC Automation & Control Systems; Computer Science, Theory & Methods; Engineering, Multidisciplinary; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Mathematics GA BP09P UT WOS:000084108600017 ER PT J AU Karp, AH Lusk, E Bailey, DH AF Karp, AH Lusk, E Bailey, DH TI 1997 Gordon Bell Prize winners SO COMPUTER LA English DT Article AB The Comprehensive Nuclear Test Ban Treaty which forbids the testing of nuclear weapons, is responsible for the dramatic performance gains reported in this year's Gordon Bell Prize competition. The connection between the treaty and the Bell Prize is simple to understand: One way to maintain confidence in the nuclear stockpile needed for national security is to use computation to tell you what you would have learned from testing. The recognition that such computations far exceeded the capability of existing computers led the US Department of Energy to initiate the Accelerated Strategic Computing Initiative (ASCI) program in high-performance computing. Four of this year's entries reported result on ASCI-RED, the first result of this program. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. NASA, Ames Res Ctr, Numer Aerodynam Simulat Program, Moffett Field, CA 94035 USA. Hewlett Packard Labs, Tech Staff, Palo Alto, CA 94304 USA. RP Karp, AH (reprint author), Hewlett Packard Labs, Tech Staff, 1501 Page Mill Rd, Palo Alto, CA 94304 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9162 J9 COMPUTER JI Computer PD JAN PY 1998 VL 31 IS 1 BP 86 EP + DI 10.1109/MC.1998.641981 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA YP591 UT WOS:000071293400010 ER PT J AU Jiang, BN AF Jiang, BN TI On the least-squares method SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article; Proceedings Paper CT Interdisciplinary Symposium on Advances in Computational Mechanics in Honor of Professor John Tinsley Oden CY JAN 12-15, 1997 CL AUSTIN, TEXAS ID FINITE-ELEMENT METHOD; ELLIPTIC-SYSTEMS; STOKES EQUATIONS AB It is shown that the theoretical basis of the general least-squares method is the bounded inverse theorem. This explains why the least-squares finite element method (LSFEM) within one mathematical/computational framework without any special treatment can provide numerical solutions for all types of partial differential equations. Error estimates of LSFEM for general and elliptic first-order systems of partial differential equations are established. As an example, the incompressible Stokes equations are considered. The principal part of the Stokes equations in the first-order velocity-pressure-vorticity formulation consists of two div-curl systems. This knowledge is employed to derive all permissible combinations of non-standard boundary conditions for the Stokes equations and to show that under these conditions the Stokes operator is bounded below in the full H-1 sense, and hence the corresponding LSFEM is optimal. The numerical results are also given to support this conclusion. C1 NASA, Inst Computat Mech Prop, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Jiang, BN (reprint author), NASA, Inst Computat Mech Prop, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 26 TC 49 Z9 50 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD JAN PY 1998 VL 152 IS 1-2 BP 239 EP 257 DI 10.1016/S0045-7825(97)00192-8 PG 19 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA YQ806 UT WOS:000071425000014 ER PT J AU Kay, H AF Kay, H TI SQSIM: a simulator for imprecise ODE models SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article DE simulation; imprecision; ODE; semiquantitative; CSTR; robustness AB This article describes a method for representing and simulating ordinary differential equation (ODE) systems which are imprecise - that is, where the ODE model contains both parametric and functional uncertainty. Such models, while useful in engineering tasks such as design and hazard analysis, are not used in practice because they require either special structures which limit the describable uncertainty or produce predictions which are extremely weak. This article describes SQSIM (for SemiQuantitative SIMulator), a system which provides a general language for representing and reasoning about many common forms of engineering uncertainty. By defining the model both qualitatively and quantitatively and by using a simulation method that combines inferences across the qualitative-to-quantitative spectrum, SQSIM produces predictions that maintain a precision consistent with the model imprecision. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kay, H (reprint author), Univ Texas, Dept Comp Sci, Austin, TX 78712 USA. NR 29 TC 9 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PY 1998 VL 23 IS 1 BP 27 EP 46 DI 10.1016/S0098-1354(98)00268-3 PG 20 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA 154KY UT WOS:000077889400003 ER PT J AU Agena, SM Bogle, IDL Cornish, ARH AF Agena, SM Bogle, IDL Cornish, ARH TI Process synthesis for particle separations using centrifuges SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article DE sloppy separation; non-sharp separation; superstructure; non-linear programming; optimisation; GAMS; MINOS AB Particle separations with centrifuges, i.e. non-sharp separations, are investigated. A methodology is studied which will lead to the creation of a cost optimal particle separation process. The particle separation task examined is specified by fixing the feed flowrate and particle composition of feed and products. According to separation breakpoints for adjacent particle size channels, a superstructure is built which contains all possible processing solutions. The optimal particle separation process is obtained using a non-linear optimisation technique (MINOS, GAMS). This technique is used to minimise an objective function in terms of centrifugation costs, subject to the formulations of the superstucture. It is demonstrated that the methodology of the superstructure can be successfully applied for particle separation processes. Cost optimal operating and design conditions are deduced for three particle separation tasks. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ London Univ Coll, Dept Chem & Biochem Engn, London WC1E 7JE, England. RP Agena, SM (reprint author), NASA, George C Marshall Space Flight Ctr, Biophys ES 76, Huntsville, AL 35812 USA. NR 7 TC 2 Z9 2 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PY 1998 VL 22 IS 3 BP 351 EP 356 DI 10.1016/S0098-1354(97)00249-4 PG 6 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA ZD382 UT WOS:000072679600003 ER PT J AU Bryson, S AF Bryson, S TI Visualization '97 brings new technical developments SO COMPUTERS IN PHYSICS LA English DT Article C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bryson, S (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 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 USA SN 0894-1866 J9 COMPUT PHYS JI Comput. Phys. PD JAN-FEB PY 1998 VL 12 IS 1 BP 53 EP 59 DI 10.1063/1.168648 PG 7 WC Computer Science, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Computer Science; Physics GA YX279 UT WOS:000072024300018 ER PT S AU Kumfert, G Pothen, A AF Kumfert, G Pothen, A BE Caromel, D Oldehoeft, RR Tholburn, M TI An object-oriented collection of minimum degree algorithms SO COMPUTING IN OBJECT-ORIENTED PARALLEL ENVIRONMENTS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 2nd International Symposium on Computing in Object-Oriented Parallel Environments CY DEC 08-11, 1998 CL SANTA FE, NEW MEXICO ID DEGREE ORDERING ALGORITHM AB The multiple minimum degree (MMD) algorithm and its variants have enjoyed more than 20 years of research and progress in generating fill-reducing orderings for sparse, symmetric, positive definite matrices. Although conceptually simple, efficient implementations of these algorithms are deceptively complex and highly specialized. In this case study, we present an object-oriented library that implements several recent minimum degree-like algorithms. We discuss how object-oriented design forces us to decompose these algorithms in a different manner than earlier codes and demonstrate how this impacts the flexibility and efficiency of our C++ implementation. We compare the performance of our code against other implementations in C or Fortran. C1 Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Kumfert, G (reprint author), Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. OI Pothen, Alex/0000-0002-3421-3325 NR 10 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65387-2 J9 LECT NOTES COMPUT SC PY 1998 VL 1505 BP 95 EP 106 PG 12 WC Computer Science, Theory & Methods SC Computer Science GA BP55F UT WOS:000085482900009 ER PT S AU Dobrian, F Kumfert, G Pothen, A AF Dobrian, F Kumfert, G Pothen, A BE Caromel, D Oldehoeft, RR Tholburn, M TI Object-oriented design for sparse direct solvers SO COMPUTING IN OBJECT-ORIENTED PARALLEL ENVIRONMENTS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 2nd International Symposium on Computing in Object-Oriented Parallel Environments CY DEC 08-11, 1998 CL SANTA FE, NEW MEXICO AB We discuss the object-oriented design of a software package for solving sparse, symmetric systems of equations (positive definite and indefinite) by direct methods. At the highest layers, we decouple data structure classes from algorithmic classes for flexibility. We describe the important structural and algorithmic classes in our design, and discuss the trade-offs we made for high performance. The kernels at the lower layers were optimized by hand. Our results show no performance loss from our object-oriented design, while providing flexibility, ease of use, and extensibility over solvers using procedural design. C1 Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Dobrian, F (reprint author), Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. OI Pothen, Alex/0000-0002-3421-3325 NR 7 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65387-2 J9 LECT NOTES COMPUT SC PY 1998 VL 1505 BP 207 EP 214 PG 8 WC Computer Science, Theory & Methods SC Computer Science GA BP55F UT WOS:000085482900022 ER PT S AU Ward, EB AF Ward, EB GP EUROPEAN SPACE AGCY EUROPEAN SPACE AGCY TI Selected university and industry partnerships in aerospace: A work in progress SO CONFERENCE ON ACADEMIC AND INDUSTRIAL COOPERATION IN SPACE RESEARCH SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Academic and Industrial Cooperation in Space Research CY NOV 04-06, 1998 CL VIENNA, AUSTRIA SP European Space Agcy, Bundesmin Wissensch & Verkehr, Austria AB Four different U.S. State-based Space Grant Consortia are examined for their relationships among academic and industrial partners. The first two consortia, the Kansas Space Grant Consortium and the New Jersey Space Grant Consortium demonstrate successful longterm partnerships between their academic institutions and industry. The second two examples, the Texas Space Grant Consortium and the California Space Grant Consortium, represent untested recent partnerships that are in the initial stages of collaboration. Common elements of a successful university-industry partnership can be extracted from the four examples. These consortia receive various amounts of federal funds from the NASA National Space Grant College and Fellowship Program. Kansas and New Jersey Space Grant consortia have half the operating budgets of Texas and California Space Grant consortia. In spite of the lower levels of funding, these two consortia have brokered successful university-industry partnerships. C1 NASA, Langley Res Ctr, NASA Space Grant Coll, Hampton, VA 23681 USA. RP Ward, EB (reprint author), NASA, Langley Res Ctr, NASA Space Grant Coll, Mail Stop 203, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-728-3 J9 ESA SP PUBL PY 1998 VL 432 BP 13 EP 21 PG 9 WC Engineering, Aerospace SC Engineering GA BM05B UT WOS:000077518200002 ER PT S AU Ward, EB Dasch, EJ AF Ward, EB Dasch, EJ GP EUROPEAN SPACE AGCY EUROPEAN SPACE AGCY TI National Aeronautics and Space Administration (NASA) programs with university and industry components SO CONFERENCE ON ACADEMIC AND INDUSTRIAL COOPERATION IN SPACE RESEARCH SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Academic and Industrial Cooperation in Space Research CY NOV 04-06, 1998 CL VIENNA, AUSTRIA SP European Space Agcy, Bundesmin Wissensch & Verkehr, Austria AB The National Aeronautics and Space Administration (NASA) administers several programs with industry components. Two of these are managed by the NASA Headquarters Office of Human Resources and Education: the National Space Grant College and Fellowship Program (Space Grant) and the NASA Experimental Program to Stimulate Competitive Research (EPSCoR). The two programs work synergistically to build research infrastructure and enhance research capability. Other NASA programs with industry components are managed by other Headquarters offices or NASA Field Center offices. All of these programs help to link industry with universities. They include the office of Aeronautics and Space Transportation Technology's Advanced General Aviation Transport Experiments (AGATE) ; the NASA Small Business Innovation Research and Small Business Technology Transfer Programs (SBIR and STIR); the NASA Commercial Technology Program; the Technology Offices at the various NASA Field Centers; and the Regional Technology Transfer Centers In addition, NASA is a primary participant in three other significant entities that involve industry and research: the National Technology Transfer Center; the Stennis Space Center Commercial Remote Sensing Program; and the (Universities Space Research Association. NASA Web site: www.nasa.gov. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ward, EB (reprint author), NASA, Langley Res Ctr, Mail Stop 203, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-728-3 J9 ESA SP PUBL PY 1998 VL 432 BP 117 EP 126 PG 10 WC Engineering, Aerospace SC Engineering GA BM05B UT WOS:000077518200016 ER PT B AU Smith, SA DelGenio, A AF Smith, SA DelGenio, A GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Horizontal variability of cirrus clouds SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc ID TURBULENCE C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Smith, SA (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 11 EP 12 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100004 ER PT B AU Geogdzhayev, IV Lacis, AA Carlson, BE Mishchenko, MI AF Geogdzhayev, IV Lacis, AA Carlson, BE Mishchenko, MI GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Remote sensing of cirrus clouds using MAS and HIS data SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc ID OCTOBER 1986 FIRE C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Geogdzhayev, IV (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. RI Mishchenko, Michael/D-4426-2012 NR 6 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 13 EP 16 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100005 ER PT B AU Jensen, EJ Ackerman, AS Toon, OB AF Jensen, EJ Ackerman, AS Toon, OB GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Dynamics and microphysics of subvisible cirrus clouds near the tropical tropopause SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jensen, EJ (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 51 EP 52 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100016 ER PT B AU Lin, RF Ackerman, TP AF Lin, RF Ackerman, TP GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Numerical simulations of cirrus anvils in nighttime conditions by a two-dimensional cloud resolving model with explicit microphysics SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Lin, RF (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 913, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 57 EP 59 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100018 ER PT B AU Wang, YS Tao, WK Simpson, J Lang, S AF Wang, YS Tao, WK Simpson, J Lang, S GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Modeling tropical convective systems: Sensitivity tests of surface fluxes, longwave and shortwave radiation SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc ID PACIFIC-OCEAN; WATER; HEAT C1 NASA, GSFC, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Wang, YS (reprint author), NASA, GSFC, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 87 EP 90 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100026 ER PT B AU Ferrier, BS Baker, RD Halverson, JB Tao, WK AF Ferrier, BS Baker, RD Halverson, JB Tao, WK GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Complex interaction between gravity waves with COARE convection SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Ferrier, BS (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Code 912, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 175 EP 178 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100052 ER PT B AU Simpson, J Halverson, JB Ferrier, BS Petersen, WA Simpson, RH Blakeslee, R Durden, SL AF Simpson, J Halverson, JB Ferrier, BS Petersen, WA Simpson, RH Blakeslee, R Durden, SL GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Cloud physics and electrification in forming Tropical Cyclone Oliver, 1993 SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Simpson, J (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 912, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 185 EP 188 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100056 ER PT B AU Shie, CL Tao, WK Simpson, J Sui, CH AF Shie, CL Tao, WK Simpson, J Sui, CH GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Impact of large-scale conditions on cloud resolving modeled climate SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Shie, CL (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 912, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 354 EP 357 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100104 ER PT B AU Tokay, A Short, DA Thiele, OW Williams, CR Ecklund, WL Gage, KS AF Tokay, A Short, DA Thiele, OW Williams, CR Ecklund, WL Gage, KS GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Characteristics of the drop size distribution in stratiform precipitation SO CONFERENCE ON CLOUD PHYSICS LA English DT Proceedings Paper CT 14th Conference on Planned and Inadvertent Weather Modification CY AUG 17-21, 1998 CL EVERETT, WA SP Amer Meteorol Soc ID RAINDROP SPECTRA; REFLECTIVITY FACTOR; VERTICAL INCIDENCE; CONVECTIVE CLOUDS; DOPPLER RADAR; SCATTERING; PARAMETERS C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tokay, A (reprint author), NASA, Goddard Space Flight Ctr, Code 910-1, Greenbelt, MD 20771 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1998 BP 391 EP 394 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BM52Y UT WOS:000079027100116 ER PT B AU Floyd, SR Trombka, JI Goldsten, JO Fiore, EM AF Floyd, SR Trombka, JI Goldsten, JO Fiore, EM GP IEEE IEEE TI Cosmic ray induced degradation in x-ray detectors on board the NEAR spacecraft SO CONFERENCE ON THE HIGH ENERGY RADIATION BACKGROUND IN SPACE LA English DT Proceedings Paper CT 1997 Conference on the High-Energy Radiation Background in Space (CHERBS 1997) / IEEE Nuclear and Space Radiation Effects Conference CY JUL 22-23, 1997 CL SNOWMASS, CO SP NASA Goddard Space Flight Ctr, Constellat Technol Corp, IEEE, NPSS Radiat Effects Comm, Nucl & Space Radiat Effects Conf AB The x-ray detectors on board the Near-Earth Asteroid Rendezvous (NEAR) spacecraft are argon gas filled proportional counters. Their resolution is checked periodically by commanding an Fe-55 radioactive source into position in front of the detector window. Low energy tailing and broadening of the 6 keV line is observed. The phenomenon observed, the mechanism behind the degradation and the impact on instrument performance are considered. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Floyd, SR (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4335-2 PY 1998 BP 34 EP 37 DI 10.1109/CHERBS.1997.660243 PG 4 WC Engineering, Aerospace; Nuclear Science & Technology; Physics, Applied SC Engineering; Nuclear Science & Technology; Physics GA BK87K UT WOS:000073723300008 ER PT B AU Clark, PE Floyd, SR Trombka, JI AF Clark, PE Floyd, SR Trombka, JI GP IEEE IEEE TI The effectiveness of the proportional counter as a solar X-ray monitor on the NEAR mission SO CONFERENCE ON THE HIGH ENERGY RADIATION BACKGROUND IN SPACE LA English DT Proceedings Paper CT 1997 Conference on the High-Energy Radiation Background in Space (CHERBS 1997) / IEEE Nuclear and Space Radiation Effects Conference CY JUL 22-23, 1997 CL SNOWMASS, CO SP NASA Goddard Space Flight Ctr, Constellat Technol Corp, IEEE, NPSS Radiat Effects Comm, Nucl & Space Radiat Effects Conf AB A proportional counter with a special mask/filter (SMPC) designed to measure solar output from 1 to 10 keV and to enhance sensitivity at higher energies where the solar nux is lower, as well as an experimental Si PIN detector (SMPN) an being used to measure solar nux on the Near Earth Asteroid Rendezvous (NEAR) mission. The complimentary nature of their performances is considered. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Clark, PE (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4335-2 PY 1998 BP 90 EP 93 DI 10.1109/CHERBS.1997.660255 PG 4 WC Engineering, Aerospace; Nuclear Science & Technology; Physics, Applied SC Engineering; Nuclear Science & Technology; Physics GA BK87K UT WOS:000073723300020 ER PT B AU Patterson, RL Hammoud, A Gerber, SS AF Patterson, RL Hammoud, A Gerber, SS GP IEEE TI Evaluation of capacitors at cryogenic temperatures for space applications SO CONFERENCE RECORD OF THE 1998 IEEE INTERNATIONAL SYMPOSIUM ON ELECTRICAL INSULATION, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE International Symposium on Electrical Insulation CY JUN 07-10, 1998 CL ARLINGTON, VA SP IEEE, Dielectr & Elect Insulat Soc AB Advanced electronic systems designed for use in planetary exploration missions must operate efficiently and reliably under the extreme low temperatures of deep space environment. In addition, spacecraft power electronics capable of low temperature operation will greatly simplify the thermal management system by eliminating the need for heating units and associated equipment and thereby reduce the size and weight of the overall power system. In this study, film, mica, solid tantalum and electric double layer capacitors were evaluated as a function of temperature in terms of their dielectric properties. These properties included capacitance stability and dielectric loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also performed on the capacitors. The results obtained are discussed and conclusions are made concerning the suitability of the capacitors investigated for low temperature applications. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Patterson, RL (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4927-X PY 1998 BP 468 EP 471 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BL23G UT WOS:000074775600108 ER PT S AU Winiecki, KB Figueiredo, MA Graessle, TL Ghuman, PS AF Winiecki, KB Figueiredo, MA Graessle, TL Ghuman, PS BE Schewel, J TI Analysis of the applicability of reconfigurable computers in satellite telemetry data processing SO CONFIGURABLE COMPUTING: TECHNOLOGY AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Configurable Computing - Technology and Applications CY NOV 02-03, 1998 CL BOSTON, MA SP SPIE Int Soc Opt Engn DE reconfigurable; adaptive; computing; computer; FPGA; NASA; GSFC; ESE; EOS; MODIS; Earth science; remote-sensing; telemetry; processing; acceleration; performance; compute; computation; bound; bottleneck AB The advent of reconfigurable computers (RCs) containing field-programmable gate-array (FPGA) ICs presents a potential solution to the problem of processing telemetry data at the high rates required to support the latest remote-sensing satellites. For example, one satellite scheduled for launch in 1999 by NASA's Earth Science Enterprise (ESE) project will generate as much Earth-science telemetry in six months as has been collected in NASA's entire 40-year history. NASA is developing software for large, expensive, conventional parallel-processing computer systems in an attempt to meet the expected processing requirements, but whether or not the resulting performance will be adequate remains unknown. For computationally-intensive, repetitive applications like this, RC technology can provide the critical performance edge. The Adaptive Scientific Data Processing (ASDP) project at NASA Goddard Space Flight Center (GSFC) has been investigating RC applications in scientific processing systems. ASDP has developed prototype RC solutions which have achieved processing speeds an order of magnitude faster than a conventional high-end computer workstation alone. This paper presents an overview of remote-sensing satellite telemetry, outlines a particular telemetry processing challenge, describes ASDP's application of RC, discusses the results, and analyzes the current and future state of the art. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Winiecki, KB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2987-2 J9 P SOC PHOTO-OPT INS PY 1998 VL 3526 BP 52 EP 59 PG 8 WC Computer Science, Hardware & Architecture SC Computer Science GA BL92X UT WOS:000077172700006 ER PT B AU Hargens, AR Hutchinson, KJ Ballard, RE Fechner, KP Murthy, G AF Hargens, AR Hutchinson, KJ Ballard, RE Fechner, KP Murthy, G BE Reed, RK Rubin, K TI Intervertebral disc: loaded on Earth and unloaded in space SO CONNECTIVE TISSUE BIOLOGY: INTEGRATION AND REDUCTIONISM SE WENNER-GREN INTERNATIONAL SERIES LA English DT Proceedings Paper CT Wenner-Gren Symposium on Connective Tissue Biology - Integration and Reductionism CY JUN, 1996 CL STOCKHOLM, SWEDEN SP Wenner Gren Fdn C1 NASA, Ames Res Ctr, Gravitat Res Branch 239 11, Moffett Field, CA 94035 USA. RP Hargens, AR (reprint author), NASA, Ames Res Ctr, Gravitat Res Branch 239 11, Moffett Field, CA 94035 USA. NR 0 TC 4 Z9 5 U1 0 U2 0 PU PORTLAND PRESS LTD PI LONDON PA 59 PORTLAND PL, LONDON W1N 3AJ, ENGLAND BN 1-85578-118-2 J9 WENN GR INT PY 1998 VL 71 BP 125 EP 133 PG 9 WC Biochemistry & Molecular Biology; Cell Biology; Physiology SC Biochemistry & Molecular Biology; Cell Biology; Physiology GA BK35X UT WOS:000071899100010 ER PT S AU Zatman, S Bloxham, J AF Zatman, S Bloxham, J BE Gurnis, M Wysession, ME Knittle, E Buffett, BA TI A one-dimensional map of B-S from torsional oscillations of the Earth's core SO CORE-MANTLE BOUNDARY REGION SE GEODYNAMICS SERIES LA English DT Proceedings Paper CT Conference on Theoretical and Observational Constraints on the Core-Mantle Boundary Region CY 1996 CL SAN FRANCISCO, CA SP AGU AB By making certain assumptions about the core we find that we may invert a time varying model of flow at the surface of the core for the root-mean-square average on axial cylinders of the component of magnetic field which links coaxial cylinders in the core (B-8), and a coefficient of "friction" at the core-mantle boundary which may also represent excitation. The primary assumption is that equatorially symmetric, axisymmetric, zonal oscillations of the flows at the top of the core are due to decadal "torsional oscillations". We invert for r.m.s. B-8 and friction within the core outside the inner core tangent cylinder from oscillations fitted to hows from 1900-1990. We find that the models of r.m.s. B-8 typically have a magnitude similar to 10(-4)T, with a minimum at midlatitudes, rising towards the tangent cylinder and towards a colatitude of 60 degrees from either side. The main characteristics of models of B-8 from inversions made with different assumptions tend to be fairly constant, but this is not so for the models of friction, perhaps because excitation varies between oscillations. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Zatman, S (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 921, Greenbelt, MD 20771 USA. NR 0 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0277-6669 BN 0-87590-530-7 J9 GEODYNAMICS PY 1998 VL 28 BP 183 EP 196 PG 14 WC Geochemistry & Geophysics; Geology; Geosciences, Multidisciplinary SC Geochemistry & Geophysics; Geology GA BM12M UT WOS:000077689600013 ER PT B AU Frieman, J AF Frieman, J BE Roszkowski, L TI Probing inflation with large-scale structure SO COSMO-97: FIRST INTERNATIONAL WORKSHOP ON PARTICLE PHYSICS AND THE EARLY UNIVERSE LA English DT Proceedings Paper CT 1st International Workshop on Particle Physics and the Early Universe (COSMO-97) CY SEP 15-19, 1997 CL AMBLESIDE, ENGLAND AB In recent years, the framework for a theory of large-scale structure formation has emerged: primordial, quasi-scale-invariant perturbations from inflation, which subsequently grow by gravitational instability in a universe with a substantial component of cold dark matter. In the near future, new galaxy surveys and cosmic microwave background experiments will provide precise complementary probes of this paradigm and ultimately provide clues to the dynamics of inflation itself. This talk highlights recent progress and expected future developments in observationally testing the inflationary scenario for structure formation. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Frieman, J (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3527-5 PY 1998 BP 279 EP 290 PG 12 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BM22G UT WOS:000078052500033 ER PT B AU Kolb, EW AF Kolb, EW BE Roszkowski, L TI Who is the inflation? SO COSMO-97: FIRST INTERNATIONAL WORKSHOP ON PARTICLE PHYSICS AND THE EARLY UNIVERSE LA English DT Proceedings Paper CT 1st International Workshop on Particle Physics and the Early Universe (COSMO-97) CY SEP 15-19, 1997 CL AMBLESIDE, ENGLAND AB Inflation is now established as part of our picture of the very early universe. There are many particle physics models of inflation; some based on superstrings, some based on supersymmetry, and some seemingly based on superstition. But which model, if any, is correct? In this talk I will discuss how we might be able to learn something about the particle physics foundation of inflation from present observations of the angular power spectrum of cosmic background radiation temperature fluctuations and the power spectrum of fluctuations in the distribution of matter. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Kolb, EW (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3527-5 PY 1998 BP 291 EP 298 PG 8 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BM22G UT WOS:000078052500034 ER PT S AU Losch, P Lyons, JJ Hagopian, J AF Losch, P Lyons, JJ Hagopian, J BE Heaney, JB Burriesci, LG TI Cryogenic optical performance of the Cassini Composite InfraRed Spectrometer (CIRS) flight telescope SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE cryogenic; optical test; encircled energy; beryllium cassegrain telescope AB The Cassini Composite InfraRed Spectrometer (CIRS) half-meter diameter beryllium flight telescope's optical performance was tested at the instrument operating temperature of 170 Kelvin. The telescope components were designed at Goddard Space Flight Center (GSFC) but fabricated out-of-house and then assembled, aligned, and tested upon receipt at GSFC. A 24-inch aperture cryogenic test facility utilizing a 1024 x 1024 CCD array was developed at GSFC specifically for this test. The telescope's image quality (measured as encircled energy), boresight stability and focus stability were measured. The gold coated beryllium design exceeded the cold image performance requirement of 80% encircled energy within a 460 micron diameter circle. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Losch, P (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 19 EP 29 DI 10.1117/12.323742 PG 11 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000003 ER PT S AU Crooke, JA Hagopian, JG AF Crooke, JA Hagopian, JG BE Heaney, JB Burriesci, LG TI Alignment and polarization sensitivity study for the Cassini-Composite InfraRed Spectrometer (CIRS) Far InfraRed (FIR) interferometer SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE far infrared; interferometry; polarization; beamsplitters; alignment; sensitivity AB The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarization interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron (mu m) thick mylar substrate with 2 mu m wide copper wires, with 2 mu m spacing (4 mu m pitch) photolithographically deposited on the substrate. This paper details the polarization sensitivity studies performed on the output polarizer/analyzer, and the alignment sensitivity studies performed on the input polarizer and beamsplitter components in the FIR interferometer. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crooke, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 30 EP 41 DI 10.1117/12.323743 PG 12 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000004 ER PT S AU Hagopian, JG Losch, P Crooke, J Mott, B Martino, AJ AF Hagopian, JG Losch, P Crooke, J Mott, B Martino, AJ BE Heaney, JB Burriesci, LG TI Shear/defocus sensitivity of the mid infrared channel (MIR) of the Composite infrared spectrometer (CIRS) for the Cassini mission to Saturn SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE infrared spectrometer; optical alignment; Cassini; CIRS; cryogenic alignment; cryogenic testing; Fourier transform spectrometer; Michelson interferometer AB The Composite Infrared Spectrometer (CIRS) of the Cassini mission to Saturn has two interferometers covering the far infrared and mid infrared wavelength region. The mid infrared wavelength interferometer has a focal plane consisting of a germanium focus lens and HgCdTe array. System level calibration of the CIRS Flight Unit indicated a discrepancy between the expected and actual signal levels. Testing on the CIRS breadboard and Engineering Unit indicated that defocus of the germanium lens could significantly reduce the modulation efficiency of the interferometer in the presence of a moderate degree of wavefront shear. Defocus of the lens in the focal plane was of concern because of the temperature dependence of the index of refraction of germanium and the nominal operation temperature of 170 K. The shear/defocus interaction was extensively investigated and correlated to a newly developed analytical model. It was eventually determined that the CIRS instrument was in focus, had no appreciable wavefront shear and was operating near theoretical limits. The shear/defocus effect is however, of considerable interest, since it has not been described in previous literature on interferometers. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Hagopian, JG (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 42 EP 51 DI 10.1117/12.323744 PG 10 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000005 ER PT S AU Martino, AJ Hagopian, JG AF Martino, AJ Hagopian, JG BE Heaney, JB Burriesci, LG TI Effects of shear, defocus, and wavefront error on the theoretical performance of the composite infrared spectrometer for Cassini SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE Cassini; CIRS; Michelson interferometer; Fourier transform spectrometer; reflectance; shear; defocus; wavefront; alignment; modulation AB The combined effects on performance of shear between die two arms, defocus of the detector, and difference in wavefront between the two arms of a Fourier transform spectrometer using cube corner retroreflectors were investigated. Performance was characterized by the amplitude of the fringe signals coming from a detector as the path-length difference was scanned. A closed-form expression was found for the combined effects of shear and defocus, and it was found that defocus had no effect in the absence of shear. The effect of wavefront en or was modeled numerically,and assumed to be independent of shear and defocus. Results were compared with measurements made on the breadboard and engineering model of the Composite Infrared Spectrometer for the Cassini mission to Saturn, and good agreement was found. C1 NASA, Goddard Space Flight Ctr, Laser Electroopt Branch, Greenbelt, MD 20771 USA. RP Martino, AJ (reprint author), NASA, Goddard Space Flight Ctr, Laser Electroopt Branch, Code 554, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 52 EP 60 DI 10.1117/12.323745 PG 9 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000006 ER PT S AU Martino, AJ Cornwell, DM AF Martino, AJ Cornwell, DM BE Heaney, JB Burriesci, LG TI Reference interferometer using a semiconductor laser/LED reference source in a cryogenic Fourier-transform spectrometer SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE Fourier transform spectrometer; laser diode; LED; Cassini; CIRS; reference interferometer AB A combination of a single mode AlGaAs laser diode and a broadband LED was used in a Michelson interferometer to provide reference signals in a Fourier transform spectrometer, the Composite Infrared Spectrometer, on the Cassini mission to Saturn. The narrowband light from the laser produced continuous fringes throughout the travel of the interferometer, which were used to control the velocity of the scan mechanism and to trigger data sampling. The broadband light from the LED produced a burst of fringes at zero path difference, which was used as a fixed position reference. The system, including the sources, the interferometer, and the detectors, was designed to work both at room temperature and at the instrument operating temperature of 170 Kelvin. One major challenge that was overcome was presentation, from room temperature to 170 K, of alignment sufficient for high modulation of fringes from the broadband source. Another was the shift of the source spectra about 30 nm toward shorter wavelengths upon cooldown. C1 NASA, Goddard Space Flight Ctr, Lasers & Electroopt Branch, Greenbelt, MD 20771 USA. RP Martino, AJ (reprint author), NASA, Goddard Space Flight Ctr, Lasers & Electroopt Branch, Code 554, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 61 EP 71 DI 10.1117/12.323746 PG 11 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000007 ER PT S AU Klotz, GL AF Klotz, GL BE Heaney, JB Burriesci, LG TI Mount for a large potassium bromide beamsplitter in a cryogenic, space application SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE potassium bromide; RTV silicone; cryogenic; optical mount; infrared; analytical model; space application AB This paper describes an approach to mounting Potassium Bromide (KBr) optical elements that are expected to survive launch vibrations and a cryogenic environment. These KBr optics constitute the beamsplitter and compensator for a high-resolution, infrared Fourier transform spectrometer (FTS). This spectrometer is part of the Tropospheric Emissions Spectrometer (TES) instrument which will operate in the 3.2 to 15.4 mu m spectral range. TES is part of NASA's Earth Observing System (EOS) initiative to better understand our Earth's environment. TES is designed to obtain data on tropospheric ozone and other gas molecules that lead to ozone formation. These data will be used to create a three-dimensional model describing the global distribution of these gases to better understand global warming and ozone depletion, TES uses a Connes interferometer where the clear aperture (CA) responsible for splitting the science beam is distinct and separated by 108 mm from the CA which recombines the split beams. KBr has a low elastic limit and a high coefficient of thermal expansion, is highly soluble in water and is susceptible to degradation from humidity. These characteristics make it a rather difficult optical material to mount and protect from environments typically resisted by glass optics. The design described here uses a diameter to thickness aspect ratio of 6:1 (based on a 190 mm diameter) resulting in a rather massive element. Due to instrument mass and volume constraints in the interferometer, a pseudo-rectangular shape for the optical elements was devised and a graphite/cyanate eater support structure was designed to minimize the mass of the entire beamsplitter assembly. Vibration isolation of the optical elements was provided by RTV silicone pads, which were also designed to meet thermal stress concerns for the 180K operating environment. Both structural and thermal analyses were performed to verify the initial design. Further vibration and thermal testing of development units is expected to uncover any unforeseen problems and to verify compliance in areas of concern. This paper addresses RTV silicone material properties required to properly support the KBr optics and predicted KBr stresses and RTV preloads and deflections derived from an analytical model of the design configuration, Results from thermal and vibration testing of development units will also be presented (if available) and compared to preliminary thermal and structural models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Klotz, GL (reprint author), CALTECH, Jet Prop Lab, MS 158-224, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 106 EP 116 DI 10.1117/12.323728 PG 11 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000011 ER PT S AU Losch, P Lyons, JJ Morell, A Heaney, JB AF Losch, P Lyons, JJ Morell, A Heaney, JB BE Heaney, JB Burriesci, LG TI Maintaining flatness of a large aperture potassium bromide beamsplitter through mounting and vibration SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE interferometry; Cassini; potassium bromide; infrared optics; cryogenic testing AB The Composite Infrared Spectrometer (CIRS) instrument on the Cassini Mission launched in October of 1997. The CIRS instrument contains a mid-infrared (MIR) and a far-infrared interferometer (FIR) and operates at 170 Kelvin. The MIR is a Michelson Fourier transform spectrometer utilizing a 76 mm (3 inch) diameter potassium bromide beamsplitter and compensator pair. The potassium bromide elements were tested to verify effects of cooldown and vibration prior to integration into the instrument. The instrument was then aligned at ambient temperatures, tested cryogenically and re-verified after vibration. The stringent design optical figure requirements for the beamsplitter and compensator included fabrication errors, mounting stresses and vibration load effects. This paper describes the challenges encountered in mounting the elements to minimize distortion and to survive vibration. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Losch, P (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 117 EP 125 DI 10.1117/12.323729 PG 9 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000012 ER PT S AU Hagopian, JG Losch, P Stewart, K Jennings, D Martino, AJ AF Hagopian, JG Losch, P Stewart, K Jennings, D Martino, AJ BE Heaney, JB Burriesci, LG TI Throughput of the Composite Infrared Spectrometer (CIRS) mid infrared (MIR) channel for the Cassini mission to Saturn SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE infrared spectrometer; optical alignment; Cassini; CIRS; throughput; modulation efficiency; Fourier transform spectrometer; Michelson interferometer AB The Composite Infrared Spectrometer (CIRS) of the Cassini mission to Saturn(1) has two interferometers covering the far infrared and mid infrared wavelength region. The instrument was aligned at ambient temperature, but operates at 170 Kelvin and has challenging interferometric alignment tolerances. Cryogenic alignment tests of the instrument indicated that it should suffer minimal degradation due to the cooldown from ambient to operational temperature. System level tests performed by the calibration team indicated a lower than expected signal level on the mid infrared (MIR) channel, while providing ambiguous optical throughput data. Therefore it became imperative to develop a metric that could be used to determine the instrument performance at both the instrument and system levels, at ambient and cryogenic temperature. Modulation efficiency and throughput measurements were performed and new analytical models developed to evaluate the status of the instrument. Methodologies are detailed, empirical and analytical data are reconciled and deviations from design values explained. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Hagopian, JG (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 185 EP 194 DI 10.1117/12.323737 PG 10 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000019 ER PT S AU Hagopian, JG Crooke, J AF Hagopian, JG Crooke, J BE Heaney, JB Burriesci, LG TI Acoustic amplification in the far infrared focal plane assembly of the Composite Infrared Spectrometer (CIRS) for the Cassini mission to Saturn SO CRYOGENIC OPTICAL SYSTEMS AND INSTRUMENTS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cryogenic Optical Systems and Instruments VIII CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE CIRS; Cassini; acoustic testing; thermopile detector AB The Composite Infrared Spectrometer (CIRS) of the Cassini mission to Saturn(1) has two interferometers covering the far infrared FIR and mid infrared, MIR wavelength region. The FIR is a polarizing Michelson interferometer, which presents a collimated output beam to the FIR focal plane. The focal plane consists of a parabolic focus mirror and an analyzer grid, which splits the output beams into transmitted and components. The two orthogonal polarizations are focussed onto two thermopile detectors, each consisting of a gold black absorber on top of a 100-nanometer thick gold foil welded to the top of two bismuth pyramids. The gold black is 30 microns thick, and the weld area is approximately 5 microns in diameter. The detectors are extremely fragile and the weld can be broken with a miniscule amount of airflow across the surface of the foil. The detectors consistently passed acoustic testing (at the detector level), to qualification levels that simulated the launch environment of the Titan IV launch vehicle. However, they experienced a 50% failure rate when installed in the focal plane assembly during instrument level acoustic tests. A test focal plane was developed with small pressure transducers in the nominal detector locations. These tests indicated over 10 dB of acoustic amplification in the focal plane in the instrument due to the geometry of the focal plane. New techniques were developed to allow testing of the focal plane without over testing the instrument, and modifications were made to the focal plane assembly to successfully attenuate the amplification. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Hagopian, JG (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2890-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3435 BP 195 EP 205 DI 10.1117/12.323738 PG 11 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA BL84U UT WOS:000076923000020 ER PT S AU Vranish, JM Germann, LM Lutter, DR Lawrence, DA AF Vranish, JM Germann, LM Lutter, DR Lawrence, DA BE Fischer, RE Germann, LM Hatheway, AE McConnell, M Smith, WJ TI Locking Lorentz Slides SO CURRENT DEVELOPMENTS IN OPTICAL DESIGN AND ENGINEERING VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Current Developments in Optical Design and Engineering VII CY JUL 22-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn AB The purpose of this paper is to introduce the concept of a Locking Lorentz Slide. Lorentz Slide actuators, which are based on the Lorentz force principal of physics and are also called Voice Coils, have earned wide-spread. use in the aerospace industry because of their superior performance (precision, force, stroke, wide temperature range including cryogenics, reliability and compactness). NASA has particularly favored these devices in their space telescopes and scientific instruments. Up to now "Voice Coils" have had to keep power on to hold position, which is limiting in many space applications. NASA, however, has found what promises to be a simple, innovative work-around with its Locking Lorentz Slide approach. This paper is an introduction to that concept and its possibilities, so, in this paper, the Locking Lorentz Slide is described, its principles of operation explained and its expected performance given. Since NASA is embarking on a development effort for this actuator more technical papers detailing hardware, tests and detailed analysis will follow. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vranish, JM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2884-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3429 BP 244 EP 251 DI 10.1117/12.328550 PG 8 WC Optics SC Optics GA BM07K UT WOS:000077547400032 ER PT S AU Kogut, A AF Kogut, A BE Sanchez, N Zichichi, A TI Spectrum of the cosmic microwave background: Results and prospects SO CURRENT TOPICS IN ASTROFUNDAMENTAL PHYSICS: PRIMORDIAL COSMOLOGY SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Current Topics in Astrofundamental Physics - Primordial Cosmology CY SEP 04-15, 1997 CL ERICE, ITALY SP NATO, Sci Affairs Div, Commiss European Communities, French Min Natl Educ & Sci Res, Italian Min Educ, Italian Min Univ & Sci Res, Sicilian Reg Govt AB The precise measurement of the long-wavelength spectrum is the last unexplored frontier for the cosmic microwave background (CMB). The Cosmic Background Explorer (COBE) showed that the CMB spectrum follows a blackbody form at millimeter and sub-mm wavelengths. Balloon-borne and ground-based measurements at longer wavelengths lack sufficient precision to measure likely spectral distortions and provide only a general confirmation of the blackbody shape: distortions as large as 5% could exist at wavelengths of several centimeters or longer without violating existing observations. Measurements at centimeter wavelengths probe different physical processes than the COBE results at shorter wavelengths. Planned measurements offer the prospect of measuring the long-wavelength free-free emission from the primeval plasma to establish the epoch and nature of reionization in the early universe. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Hughes STX, Greenbelt, MD 20771 USA. RP Kogut, A (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Hughes STX, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5045-6 J9 NATO ADV SCI I C-MAT PY 1998 VL 511 BP 359 EP 376 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL56L UT WOS:000075896400011 ER PT S AU Kogut, A AF Kogut, A BE Sanchez, N Zichichi, A TI Large-scale anisotropy of the cosmic microwave background SO CURRENT TOPICS IN ASTROFUNDAMENTAL PHYSICS: PRIMORDIAL COSMOLOGY SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on Current Topics in Astrofundamental Physics - Primordial Cosmology CY SEP 04-15, 1997 CL ERICE, ITALY SP NATO, Sci Affairs Div, Commiss European Communities, French Min Natl Educ & Sci Res, Italian Min Educ, Italian Min Univ & Sci Res, Sicilian Reg Govt AB The origin of large scale structure in the Universe is one of the most fundamental issues in cosmology. Gravitational instability models hold that large-scale structure forms as the result of gravitational amplification of initially small perturbations in the primordial density distribution. The COBE-DMR maps of the cosmic microwave background anisotropy measure the primordial density distribution on super-horizon scales and offer a unique probe of the "initial conditions" for structure formation. I will present several statistical tests of the large-scale CMB anisotropy, with an emphasis on what what we can learn, what we can't, and why. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Hughes STX, Greenbelt, MD 20771 USA. RP Kogut, A (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Hughes STX, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-5045-6 J9 NATO ADV SCI I C-MAT PY 1998 VL 511 BP 377 EP 407 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL56L UT WOS:000075896400012 ER PT J AU Hoge, FE Wright, CW Swift, RN Yungel, JK Berry, RE Mitchell, R AF Hoge, FE Wright, CW Swift, RN Yungel, JK Berry, RE Mitchell, R TI Fluorescence signatures of an iron-enriched phytoplankton community in the eastern equatorial Pacific Ocean SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID COLOR MEASUREMENT; AIRBORNE; CHLOROPHYLL; PIGMENTS AB Laser-induced fluorescence profiles of chlorophyll and phycoerythrin pigments and chromophoric dissolved organic matter (CDOM) fluorescence acquired over an iron-enriched phytoplankton patch are compared to profiles made over adjacent, naturally occurring phytoplankton patches. A total of four airborne missions were flown during an 8 day period following the release of the iron-rich fertilizer. Analyses of the airborne laser-induced fluorescence profiles from the upper-ocean layer reveal: (1) Ship-dispersed iron enhances localized phytoplankton production in high-nutrient/low-chlorophyll regions such as found in the eastern equatorial Pacific Ocean. (2) The chlorophyll concentration within the iron-enriched phytoplankton patch exceeded levels of chlorophyll found in naturally occurring phytoplankton patches located outside the enriched region. (3) An increase in phycoerythrin fluorescence was observed within the enriched region in correspondence with the elevated chlorophyll fluorescence. However, the phycoerythrin/chlorophyll fluorescence ratio was lower within the enriched patch than in naturally occurring phytoplankton patches outside of the enriched region. (4) No above-background chromorophoric dissolved organic matter (CDOM) fluorescence was observed in the enriched patch. Elevated CDOM fluorescence was associated with some of the naturally occurring phytoplankton patches outside the enriched region, while other such phytoplankton patches showed no measurable increase in CDOM over background levels. (5) The surface layer manifestation of the patch was observed to be transported to the north and west in close agreement with the drogue positions. No elevated surface layer chlorophyll fluorescence was seen in the vicinity of the ship as it sampled the submerged fraction at the time of the 30 October and I November overflights. The phycoerythrin pigment fluorescence emission was insensitive to ambient cloud-induced downwelling irradiance variability, while at the same time the chlorophyll fluorescence displayed considerable quenching for which corrections were made using the airborne downwelling irradiance. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. EG&G, Wallops Island, VA 23337 USA. CSC, Wallops Island, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 21 TC 9 Z9 11 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 1998 VL 45 IS 6 BP 1073 EP 1082 DI 10.1016/S0967-0645(98)00020-4 PG 10 WC Oceanography SC Oceanography GA 137ZG UT WOS:000076946500008 ER PT J AU Hoge, FE Wright, CW Swift, RN Yungel, JK Berry, RE Mitchell, R AF Hoge, FE Wright, CW Swift, RN Yungel, JK Berry, RE Mitchell, R TI Airborne bio-optics survey of the Galapagos Islands margins SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article AB Aircraft and ship surveys of the Galapagos Islands were conducted to address the hypothesized influence of "island-leached" iron upon phytoplankton production. This paper describes the airborne survey of the Galapagos Islands that composed the second phase of a two-part study of the influence of iron on phytoplankton production in high-nutrient/low-chlorophyll (HNLC) regions. A single bio-optics airborne survey transect along 92 degrees W from 1 degrees N to 2 degrees S was executed on 25 October 1993 in order to provide initial reconnaissance spatial and temporal sampling of the oceanic region west of the Galapagos Islands. A more extensive airborne bio-optics survey of the entire Galapagos Islands region was conducted on 3 November 1993. This expanded flight survey was made along all the ship cruise tracks of the R.V. Columbus Iselin originally planned for 15-27 November 1993. Analysis of the surface-layer airborne laser-induced and water-Raman normalized chlorophyll, phycoerythrin, and chromophoric dissolved organic matter (CDOM) fluorescence, SST, and AXBT (airborne expendable bathythermograph) data suggest that: (1) the regional distribution of phytoplankton and dissolved organic matter is dominated by the strong east-west thermal boundary located both east and west of the Galapagos Islands; (2) the source for the elevated phytoplankton patches west of the Galapagos Islands is from upwelling rather than aeolian sources or from the westward drift of iron and nutrients leached from the islands themselves or offshore shallow bottom sources; (3) the introduction of subsurface water to the surface may occur in episodic events rather than as a steady-state process; and (4) the chronic high chlorophyll west of the Galapagos Islands noted in processed Coastal Zone Color Scanner (CZCS) images may be due, at least in part, to the presence of elevated levels of chromophoric dissolved organic matter (CDOM) absorption. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. EG&G, Wallops Island, VA 23337 USA. CSC, Wallops Island, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. NR 5 TC 4 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 1998 VL 45 IS 6 BP 1083 EP + DI 10.1016/S0967-0645(98)00021-6 PG 9 WC Oceanography SC Oceanography GA 137ZG UT WOS:000076946500009 ER PT J AU Dickey, T Marra, J Sigurdson, DE Weller, RA Kinkade, CS Zedler, SE Wiggert, JD Langdon, C AF Dickey, T Marra, J Sigurdson, DE Weller, RA Kinkade, CS Zedler, SE Wiggert, JD Langdon, C TI Seasonal variability of bio-optical and physical properties in the Arabian Sea: October 1994-October 1995 SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID SARGASSO SEA; UPPER OCEAN; ATLANTIC; BLOOM AB A mooring instrumented with optical and physical sensors within the upper 300 m was deployed for two consecutive 6-month periods (October 15, 1994 through October 20, 1995; sampling intervals of a few minutes) in the central Arabian Sea (15 degrees 30'N, 61 degrees 30'E). Both the Northeast Monsoon (November 1, 1994-February 15, 1995) and Southwest Monsoon (June 1-September 15, 1995) were observed. During the NE Monsoon, wind speeds averaged 6 ms(-1) and reached up to 15 ms(-1) during the SW Monsoon. Intermonsoon periods (Spring February 16-May 31, 1995; and Fall September 16-October 15, 1995) were characterized by weak and variable winds. Shortwave radiation and photosynthetically available radiation (PAR) displayed half-yearly cycles, peaking during the Intermonsoon periods. Two mixed-layer depth definitions have been used to describe our results. The first is based on a temperature difference of 0.1 degrees C of the surface temperature, MLD0.1 degrees C, and the second is based on a difference of 1.0 degrees C, MLD1.0 degrees C. The maximum Winter mixed layer depth (MLD1.0 degrees C similar to 110 m) was deeper than the Summer mixed layer (MLD1.0 degrees C similar to 80 m), primarily because of surface cooling and convection. A half-yearly cycle in chlorophyll a was evident with greater values occurring during each Monsoon and into the Intermonsoon periods. High chlorophyll a values associated with cool mesoscale features were also apparent during each Monsoon. These mesoscale features and others have been identified using remotely sensed sea-surface height anomaly maps. Time-series of the 1% light level depth, h(1%), tracked the depth-integrated chlorophyll a. In general, h(1%) was deeper than MLD1.0 degrees C during the latter half of the Spring Intermonsoon (SIM) (with low chlorophyll a periods) and shallower than MLD1.0 degrees C during the latter portions of the Monsoons (high chlorophyll a periods). During the SIM, the penetrative components of net solar radiation at the base of the mixed layers, E-n(MLD1.0 degrees C) and E-c(MLD0.1 degrees C), reached values of similar to 40 and 75 W m(-2), respectively, when the net surface heat flux was 120 W m-2. The highest mixed layer radiant heating rates occurred during the Intermonsoon periods with peak values greater than 0.2 and 0.1 degrees C d(-1) for MLD0.1 degrees C and MLD1(.0 degrees C) respectively. Our results indicate that biological variability is significant for the upper ocean heat budget of the central Arabian Sea during the SIM. The present results, in conjunction with those presented in Marra et al. (1998) and Honjo et al. (1998), demonstrate strong coupling of upper ocean biological processes with deep ocean particulate organic carbon fluxes. These collective results suggest that the timing and amplitudes of phytoplankton blooms associated with both seasonal stratification and eddies are quite well-correlated with relatively rapid export flux of organic carbon to the deep ocean. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Santa Barbara, Ocean Phys Lab, Goleta, CA 93117 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NASA, USRA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dickey, T (reprint author), Univ Calif Santa Barbara, Ocean Phys Lab, 6487 Calle Real,Suite A, Goleta, CA 93117 USA. NR 37 TC 84 Z9 85 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 1998 VL 45 IS 10-11 BP 2001 EP 2025 DI 10.1016/S0967-0645(98)00061-7 PG 25 WC Oceanography SC Oceanography GA 152FF UT WOS:000077765000004 ER PT J AU Buesseler, K Ball, L Andrews, J Benitez-Nelson, C Belastock, R Chai, F Chao, Y AF Buesseler, K Ball, L Andrews, J Benitez-Nelson, C Belastock, R Chai, F Chao, Y TI Upper ocean export of particulate organic carbon in the Arabian Sea derived from thorium-234 SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID EQUATORIAL PACIFIC; SEDIMENT TRAPS; PARTICLE-FLUX; TH-234; DISEQUILIBRIA; WATER; ISOTOPES; SEAWATER; BIOMASS; REMOVAL AB Thorium-234 is used in the Arabian Sea as a tracer of sinking particle fluxes. Samples were collected from January to August 1995 on four cruises during the Northeast Monsoon, the Spring Intermonsoon and the mid- and late-Southwest Monsoon periods. In this study, (234)Th activity distributions are used to quantify the (234)Th flux On Sinking particles, and the measured ratio of particulate organic carbon (POC) to particulate (234)Th is used to convert from (234)Th to POC export at 100 m. The calculated POC fluxes range from <1 to >25 mmols C m(-2) d(-1), and strong seasonal and spatial gradients are observed. The single largest feature is a basin-wide export maximum associated with the late-SW Monsoon cruise when POC export rates are 17-28% of the observed primary production rates along the southern sampling line. During all other cruises, this export ratio is <2-10%, with an increase near shore where POC fluxes are generally elevated. Also, during the Spring Intermonsoon, a POC export maximum is observed along the northern sampling line. Both this Spring export feature and late-SW Monsoon flux maximum appear to be associated with a phytoplankton community structure dominated by diatoms. The timing of the late-SW Monsoon flux peak agrees with the observed flux maximum in the deep moored time-series sediment traps (Honjo et al., 1998). This dramatic increase in export between the mid- and late-SW Monsoon also corresponds to measured decreases in the stocks of total organic C in the upper 150 m (Hansell and Peltzer, 1998) and a sharp decline in surface water Al and Fe (Measures and Vink, 1998). These 100 m flux results, plus a series of POC flux profiles, allow for a more complete understanding of the magnitude and timing of sub-euphotic zone export in the Arabian Sea. (C) 1998 Elsevier Science Ltd. Ail rights reserved. C1 Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02540 USA. Univ Maine, Sch Marine Sci, Orono, ME 04469 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buesseler, K (reprint author), Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02540 USA. EM kbuesseler@whoi.edu OI Benitez-Nelson, Claudia/0000-0002-1004-5048 NR 52 TC 146 Z9 151 U1 1 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 1998 VL 45 IS 10-11 BP 2461 EP 2487 DI 10.1016/S0967-0645(98)80022-2 PG 27 WC Oceanography SC Oceanography GA 152FF UT WOS:000077765000020 ER PT S AU Bazhenov, AV Boris, AV Kovaleva, NN Samoilov, AV Yeh, NC Vasquez, RP AF Bazhenov, AV Boris, AV Kovaleva, NN Samoilov, AV Yeh, NC Vasquez, RP BE Donecker, J Rechenberg, I TI Spectra of dipole-active optical phonons in La0.7Ca0.3MnO3 epitaxial films SO DEFECT RECOGNITION AND IMAGE PROCESSING IN SEMICONDUCTORS 1997 SE INSTITUTE OF PHYSICS CONFERENCE SERIES LA English DT Article; Proceedings Paper CT 7th International Conference on Defect Recognition and Image Processing in Semiconductors (DRIP-VII) CY SEP 07-10, 1997 CL TEMPLIN, GERMANY SP Deutsch Forsch Gemeinschaft, Freiberger Compound Mat, Gesell Forderung Angewandten Opt Optoelektr Quantenelektr & Spektroskopie EV, Wacker Siltron AG ID SRTIO3 AB The reflectance of La0.7Ca0.3MnO3 epitaxial films on perovskite substrates with a range of lattice constants is studied in the frequency range 50 - 5000 cm(-1). The results derived by modeling the spectra indicate that the internal optical phonon modes of the MnO6 octahedra are strongly affected by the substrate-induced lattice distortion standing for the strong electron-phonon interaction in this system. C1 Chernogolovka Solid State Phys Inst, Chernogolovka 142432, Moscow Distr, Russia. CALTECH, Dept Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bazhenov, AV (reprint author), Chernogolovka Solid State Phys Inst, Chernogolovka 142432, Moscow Distr, Russia. RI Kovaleva, Natalia/B-8595-2016; Kovaleva, Natalia/H-2520-2014 NR 11 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0951-3248 BN 0-7503-0500-2 J9 INST PHYS CONF SER PY 1998 VL 160 BP 429 EP 432 PG 4 WC Materials Science, Characterization & Testing; Physics, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA BK78H UT WOS:000073379500089 ER PT S AU Bergman, LA Morookian, J Yeh, C AF Bergman, LA Morookian, J Yeh, C BE Chen, RT Lome, LS TI WDM component requirements for bit-parallel fiber optic computer networks SO DESIGN AND MANUFACTURING OF WDM DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Design and Manufacturing of WDM Devices CY NOV 04-05, 1997 CL DALLAS, TX SP Soc Photo Opt Instrumentat Engineers DE wavelength division multiplexed propagation; nonlinear pulses; solitons; bit-parallel link AB The device specifications for an all optical bit-parallel WDM single fiber link for the cluster computer network community are intended for dissemination to the opto-electronic device research community to stimulate synergy between the two, ultimately leading to early availability of new devices to the computer network researchers. It is also hoped that early adoption of these devices by the research community will promote limited production of these devices by industry. Background information on our investigation of this problem will first be given. Then the detailed design of a long distance (32 km) all optical bit-parallel WDM single-fiber link with 12 bit-parallel channels having 1 Gbytes/sec capacity is given. The speed-distance product for this link is 32 Gbytes/sec-km. Means to improve this speed-distance product using the pulse shepherding effect will be described. Finally, a detailed description of the BP-WDM component requirements is given. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bergman, LA (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2667-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3234 BP 2 EP 13 DI 10.1117/12.300917 PG 12 WC Optics SC Optics GA BK57U UT WOS:000072611800001 ER PT S AU Wu, C Melville, D Yousefi, GH Puetz, N Shepherd, F AF Wu, C Melville, D Yousefi, GH Puetz, N Shepherd, F BE Chen, RT Lome, LS TI A novel compact optical cross-point switch on InP SO DESIGN AND MANUFACTURING OF WDM DEVICES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Design and Manufacturing of WDM Devices CY NOV 04-05, 1997 CL DALLAS, TX SP Soc Photo Opt Instrumentat Engineers DE optical switch; digital optical switch; InP; optical cross-point; integrated optics; polarization independent; high speed; optical protection switch; optical cross-connect; ATM optical switch AB In this paper, we propose and demonstrate a novel compact optical cross point switch configuration using electrical current tuning. The device is made on InP/InGaAsP material. It has a digital switching characteristics, a switching current of 40 mA and switching speed of nanosecond. For NxN switches, only N electrodes are needed. The switching electrode is only 600-mu m long. It has a cross-talk of -40 dB. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wu, C (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2667-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3234 BP 42 EP 49 DI 10.1117/12.300937 PG 8 WC Optics SC Optics GA BK57U UT WOS:000072611800006 ER PT S AU Javadi, H Bendrihem, D Blaes, B Boykins, K Cardone, J Cruzan, C Gibbs, J Goodman, W Lieneweg, U Michalik, H Narvaez, P Perrone, D Rademacher, J Snare, R Spencer, H Sue, M Weese, J AF Javadi, H Bendrihem, D Blaes, B Boykins, K Cardone, J Cruzan, C Gibbs, J Goodman, W Lieneweg, U Michalik, H Narvaez, P Perrone, D Rademacher, J Snare, R Spencer, H Sue, M Weese, J BE Dubey, AC Harvey, JF Broach, JT TI Multiprobe in-situ measurement of magnetic field in a minefield via a distributed network of miniaturized low-power integrated sensor system for detection of magnetic field anomalies SO DETECTION AND REMEDIATION TECHNOLOGIES FOR MINES AND MINELIKE TARGETS III, PTS 1 AND 2 SE Proceedings of SPIE LA English DT Proceedings Paper CT SPIE Conference on Detection and Remediation Technologies for Mines and Minelike Targets III CY APR 13-17, 1998 CL ORLANDO, FL SP SPIE DE Free-Flying-Magnetometer; integrated sensor system; multi-probe measurement system; mine-detection; flux-gate magnetometer; sun-angle sensor AB Based on technologies developed for the Jet Propulsion Laboratory (JPL) Free-Flying-Magnetometer (FFM) concept,(1) we propose to modify the present design of FFMs for detection of mines and arsenals with large magnetic signature. The result will be an integrated miniature sensor system capable of identifying local magnetic field anomaly caused by a magnetic dipole moment. Proposed integrated sensor system is in line with the JPL technology road-map for development of autonomous, intelligent, networked integrated systems with a broad range of applications. In addition, advanced sensitive magnetic sensors (e.g; silicon micromachined magnetometer, laser pumped helium magnetometer) are being developed for future NASA space plasma probes. It is envisioned that a fleet of these Integrated Sensor Systems (ISS) units will be dispersed on a mine-field via an aerial vehicle (a low-flying airplane or a helicopter). The number of such sensor systems in each fleet and the corresponding in-situ probe-grid cell size is based on the strength of magnetic anomaly of the target and ISS measurement resolution of magnetic field vector. After a specified time, ISS units will transmit the measured magnetic field smd attitude data to an air-borne platform for further data processing. The cycle of data acquistion and transmission will be continued until batteries run out. Data analysis will allow a local deformation of the Earth's magnetic field vector by a magnetic dipole moment to be detected. Each ISS unit consists of miniaturized sensitive 3-axis magnetometer, high resolution analog-to-digital converter (ADC), Field Programmable Gate Array (FPGA)-based data subsystem, Li-batteries and power regulation circuitry, memory, S-band transmitter, single-patch antenna, and a sun angle sensor. ISS unit is packaged with non-magnetic components and the electronic design implements low-magnetic signature circuits. Care is undertaken to guarantee no corruption of magnetometer sensitivity as a result of its close proximity with the electronics and packaging materials. Accurate calibration of the magnetometer response in advance will allow removing the effects of unwanted disturbances. Improvements of the magnetometer performance in the areas of the orthogonality, drift, and temperature coefficient of offset and scale factor are required. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Javadi, H (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hjavadi@pop.jpl.nasa.gov NR 0 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2841-8 J9 PROC SPIE PY 1998 VL 3392 BP 23 EP 32 DI 10.1117/12.324203 PG 10 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL85T UT WOS:000076961000003 ER PT S AU Olson, CF Matthies, LH AF Olson, CF Matthies, LH BE Dubey, AC Harvey, JF Broach, JT TI Visual ordnance recognition for clearing test ranges SO DETECTION AND REMEDIATION TECHNOLOGIES FOR MINES AND MINELIKE TARGETS III, PTS 1 AND 2 SE Proceedings of SPIE LA English DT Proceedings Paper CT SPIE Conference on Detection and Remediation Technologies for Mines and Minelike Targets III CY APR 13-17, 1998 CL ORLANDO, FL SP SPIE DE ordnance recognition; stereo vision; edge detection; adaptive scale selection; parallel line extraction; cylinder detection; autonomous munitions clearance AB We describe a method for recognizing surface-lying ordnance in test ranges using stereo range information and image edge maps. This method is to be used by an unmanned ground vehicle (UGV) surveying the test range for autonomous clearing of ordnance. We concentrate on a particular type of cylindrical ordnance (BLU-97) in current usage in U.S. military test ranges. In order to locate instances of the ordnance, we employ a stereo pair of cameras to be mounted on top of a UGV. Parallel segments corresponding to the occluding contours of the ordnance are detected in the imagery using robust and efficient model extraction techniques. The stereo range data is used to adaptively select the local scale for edge detection and to place constraints on the search space for the parallel segment extraction. Initial tests indicate that robust recognition is possible in near real-time with a low rate of false positives. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 107-102, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2841-8 J9 PROC SPIE PY 1998 VL 3392 BP 122 EP 133 DI 10.1117/12.324184 PG 12 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL85T UT WOS:000076961000013 ER PT S AU Lau, B Chao, TH AF Lau, B Chao, TH BE Dubey, AC Harvey, JF Broach, JT TI Aided target recognition processing of MUDSS sonar data SO DETECTION AND REMEDIATION TECHNOLOGIES FOR MINES AND MINELIKE TARGETS III, PTS 1 AND 2 SE Proceedings of SPIE LA English DT Proceedings Paper CT SPIE Conference on Detection and Remediation Technologies for Mines and Minelike Targets III CY APR 13-17, 1998 CL ORLANDO, FL SP SPIE DE sonar; wavelets; Hermite polynomials; neural network; morphological image processing AB The Mobile Underwater Debris Survey System (MUDSS) is a collaborative effort by the Navy and the Jet Propulsion Lab to demonstrate multi-sensor, real-time, survey of underwater sites for ordnance and explosive waste (OEW). We describe the sonar processing algorithm, a novel target recognition algorithm incorporating wavelets, morphological image processing, expansion by Hermite polynomials, and neural networks. This algorithm has found all planted targets in MUDSS tests and has achieved spectacular success upon another Coastal Systems Station (CSS) sonar image database. C1 NASA, JPL, Pasadena, CA 91125 USA. RP Lau, B (reprint author), NASA, JPL, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2841-8 J9 PROC SPIE PY 1998 VL 3392 BP 234 EP 242 DI 10.1117/12.324194 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL85T UT WOS:000076961000024 ER PT S AU Shi, ZQ Stahle, CM Shu, P AF Shi, ZQ Stahle, CM Shu, P BE Liang, P Wigdor, M Frederick, WGD TI Fabrication of high performance CdZnTe strip detector arrays SO DETECTORS, FOCAL PLANE ARRAYS, AND IMAGING DEVICES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Detectors, Focal Plane Arrays, and Imaging Devices II CY SEP 18-19, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, COS, COEMA DE CdZnTe strip detector; leakage current; energy resolution; wire bonding; chemical etching; post annealing AB Cadmium zinc telluride (CdZnTe) has been applied as a X-ray and gamma-ray radiation detector due to its large bandgap and high atomic number which gives low leakage current and good absorption efficiency. In addition, the CdZnTe detectors can be operated at room temperature with very good energy resolution and excellent spatial resolution. The main challenges in fabricating a large area CdZnTe strip detector array are the requirements of low leakage current in the individual strips of each detector and the good adhesion of the pad metal to the CdZnTe surface for wire bonding. The Detector Systems Branch at Goddard Space Flight Center has successfully fabricated the double sided CdZnTe strip detectors for a 6 x 6 array. The strip detector array has 36 double sided detectors with each detector having 127 strips and a guard ring on each side with a spatial resolution <100 mu m. The total area of the array is 60 cm(2) with 762 x 762 strips to give 580,000 pixels - a factor of 100 better than other CdZnTe or scintillator arrays. In this paper, we will present our novel processing for fabricating such high performance strip detectors. The leakage current, interstrip resistance and energy resolution were studied as a function of different etchants/time and post-annealing temperature. The effects of chemical etching and post annealing on the CdZnTe surface and interface property were also discussed. C1 NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Greenbelt, MD 20771 USA. RP Shi, ZQ (reprint author), NASA, Goddard Space Flight Ctr, Raytheon STX Corp, Code 553, Greenbelt, MD 20771 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3014-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3553 BP 90 EP 96 DI 10.1117/12.318090 PG 7 WC Engineering, Multidisciplinary; Optics; Physics, Applied SC Engineering; Optics; Physics GA BL77Q UT WOS:000076705700014 ER PT S AU Gunapala, SD Bandara, SV Liu, JK Luong, E Bock, JJ Ressler, ME Werner, MW AF Gunapala, SD Bandara, SV Liu, JK Luong, E Bock, JJ Ressler, ME Werner, MW BE Liang, P Wigdor, M Frederick, WGD TI Quantum well infrared photodetectors (QWIPs) for astronomy SO DETECTORS, FOCAL PLANE ARRAYS, AND IMAGING DEVICES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Detectors, Focal Plane Arrays, and Imaging Devices II CY SEP 18-19, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, COS, COEMA DE quantum wells; infrared detectors; focal plane arrays; astronomy; 1/f noise AB In recent years, many research groups in the world have demonstrated large format Quantum Well Infrared Photodetector (QWIP) focal plane arrays for various thermal imaging applications. QWIPs as opposed to conventional low bandgap infrared detectors, are limited by thermionic dark current and not tunneling currents down to 30K or less. As a result the performance of QWIPs can be substantially improved (orders of magnitude) by cooling from 70K to 30K. Cooling does not induce any nonuniformity or 1/f noise in QWIP focal plane arrays. In this paper, we discuss the development of highly uniform long-wavelength QWIPs for astronomical applications. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3014-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3553 BP 146 EP 153 DI 10.1117/12.318096 PG 8 WC Engineering, Multidisciplinary; Optics; Physics, Applied SC Engineering; Optics; Physics GA BL77Q UT WOS:000076705700021 ER PT J AU Miyoshi, K AF Miyoshi, K TI Structures and mechanical properties of natural and synthetic diamonds SO DIAMOND FILMS AND TECHNOLOGY LA English DT Review DE solid lubrication; diamond coatings; tribology; diamond's structures and properties ID SURFACE AB A revolution in the diamond technology is in progress, as the low-pressure process becomes an industrial reality. It will soon be possible to take advantage of the demanding properties of diamond to develop a myriad of new applications, particularly for self-lubricating, wear-resistant, and superhard coatings. The production of large diamond films or sheets at low cost, a distinct possibility in the not-too-distant future, may drastically change tribology technology, particularly regarding solid lubricants and lubricating materials and systems. This paper reviews the structures and properties of natural and synthetic diamonds to gain a better understanding of the tribological properties of diamond and related materials. Atomic and crystal structure, impurities, mechanical properties, and indentation hardness of diamond are described. C1 NASA, Cleveland, OH 44135 USA. RP Miyoshi, K (reprint author), NASA, Cleveland, OH 44135 USA. NR 24 TC 4 Z9 4 U1 3 U2 14 PU MYU, SCIENTIFIC PUBLISHING DIVISION PI TOKYO PA 1-23-3-303 SENDAGI, TOKYO, 113-0022, JAPAN SN 0917-4540 J9 DIAMOND FILM TECHNOL JI Diam. Films Technol. PY 1998 VL 8 IS 3 BP 153 EP 172 PG 20 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA 155YY UT WOS:000077975600003 ER PT B AU Kahn, R AF Kahn, R BE Weisberg, S TI Why do we need discrete global grids for satellite remote sensing? SO DIMENSION REDUCTION, COMPUTATIONAL COMPLEXITY AND INFORMATION SE COMPUTING SCIENCE AND STATISTICS (SERIES) LA English DT Proceedings Paper CT 30th Symposium on Interface Between Computing Science and Statistics CY MAY 13-16, 1998 CL MINNEAPOLIS, MN SP Nat Security Agcy, Univ Minnesota, Coll Liberal Arts, SAS Inst Inc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kahn, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 0 TC 1 Z9 1 U1 0 U2 1 PU INTERFACE FOUNDATION NORTH AMERICA PI FAIRFAX PA PO BOX 7460, FAIRFAX, VA 22039-7460 USA BN 1-886658-05-6 J9 COMP SCI STAT PY 1998 VL 30 BP 285 EP 285 PG 1 WC Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods; Statistics & Probability SC Computer Science; Mathematics GA BN90B UT WOS:000083408300049 ER PT J AU Lu, HI Miller, TL AF Lu, HI Miller, TL TI Characteristics of annulus baroclinic flow structure during amplitude vacillation SO DYNAMICS OF ATMOSPHERES AND OCEANS LA English DT Article ID ROTATING FLUID ANNULUS; THERMALLY DRIVEN; WAVES; ATMOSPHERE; MODEL AB An investigation is made of the mechanics of amplitude vacillation in a numerically simulated rotating annulus flow system. Amplitude vacillation is characterized by a periodic change of vertical wave structure in concert with growth and decay of wave amplitude and phase speed. The temperature wave amplitude profile for the dominant component consists of three local maxima: (1) lower boundary layer, (2) upper half layer and (3) lower half layer. The lower layer waves lead the time-dependent structural variation during vacillation. Two types of amplitude vacillation found in the experimental measurements (Buzyna et al., 1989: J. Atmos. Sci. 46, 2716-2729) can be distinguished in the temperature wave by whether the lower layer waves split from and travel behind the upper layer waves by one wave period in each cycle of vacillation. Linear eigenvalue analyses with respect to the instantaneous axisymmetric state at various points in time are performed to elucidate the simple interaction between the dominant wave and the zonal mean state, During the vacillation cycle, the zonal mean state is modified by the wave, which causes a change in growth rate and vertical structure of the linearly most unstable eigenmode. This, in turn, forces the actual changes of the nonlinear solutions. (C) 1997 Elsevier Science B.V. C1 Inst Global Change Res & Educ, Huntsville, AL 35806 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Lu, HI (reprint author), Inst Global Change Res & Educ, 977 Explorer Blvd, Huntsville, AL 35806 USA. NR 25 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0265 J9 DYNAM ATMOS OCEANS JI Dyn. Atmos. Oceans PD JAN PY 1998 VL 27 IS 1-4 BP 485 EP 503 DI 10.1016/S0377-0265(97)00027-4 PG 19 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography GA YV598 UT WOS:000071842700028 ER PT J AU Lu, HI Miller, TL AF Lu, HI Miller, TL TI Wave dispersion in a rotating, differentially-heated fluid model SO DYNAMICS OF ATMOSPHERES AND OCEANS LA English DT Article ID GEOSTROPHIC TURBULENCE; BAROCLINIC INSTABILITY; NUMBER SELECTION; ANNULUS; FLOW; TRANSITION; PACKETS; DRIVEN AB An investigation is made of the mechanics of the wave dispersion phenomenon obtained in a numerical simulation of the rotating annulus flow system. Wave dispersion is characterized by the presence of two quasi-steady sideband baroclinic waves of comparable amplitudes and different phase speeds, The recurrence of wavepacket formation downstream of the wave train can be kinematically related to the group velocity, The vertical structure of the temperature wave for the primary wavenumber consists of a upper layer and a lower layer maximum, while the secondary wavenumber lacks the lower layer maximum. The primary wave is baroclinically active as it is maintained by the zonal flow baroclinicity, while the secondary wave is baroclinically passive in the sense that it is linearly stable with respect to the instantaneous zonal flow, although it exhibits a strong baroclinic energy conversion, Wave-wave interactions enhance the baroclinic energy conversion of the secondary wave by increasing the pressure-temperature phase difference, counteracting the negative nonlinear energy transfer and the stabilizing effect of the zonal mean basic state. (C) 1997 Elsevier Science B.V. C1 Inst global Change Res & Educ, Huntsville, AL 35806 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Lu, HI (reprint author), Inst global Change Res & Educ, 977 Explorer Blvd, Huntsville, AL 35806 USA. NR 31 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0265 J9 DYNAM ATMOS OCEANS JI Dyn. Atmos. Oceans PD JAN PY 1998 VL 27 IS 1-4 BP 505 EP 526 DI 10.1016/S0377-0265(97)00028-6 PG 22 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Oceanography GA YV598 UT WOS:000071842700029 ER PT J AU Jenniskens, P Butow, SJ Fonda, M AF Jenniskens, P Butow, SJ Fonda, M TI The 1999 Leonid multi-instrument aircraft campaign - An early review SO EARTH MOON AND PLANETS LA English DT Article DE airborne astronomy; astrobiology; chemistry; comets; composition; elves; exobiology; instrumental techniques; Leonid MAC; Leonids 1999; lower thermosphere; meteoroids; meteor storm; meteors; mesosphere; orbital dynamics; satellite impact hazard; sprites ID METEORS; SHOWER; TRAILS; LIDAR AB Two B707-type research aircraft of the 452(nd) Flight Test Squadron at Edwards Air Force Base were deployed to study the Leonid meteor storm of 1999 over the Mediterranean Sea on Nov. 18. The mission was sponsored by various science programs of NASA, and offered an international team of 35 researchers observing conditions free of clouds and low altitude extinction at a prime location for viewing the storm. This 1999 Leonid Multi-Instrument Aircraft Campaign followed a similar effort in 1998, improving upon mission strategy and scope. As before, spectroscopic and imaging experiments targeted meteors and persistent trains, but also airglow, aurora, elves and sprites. The research aimed to address outstanding questions in astrobiology, planetary science, astronomy, and upper atmospheric research. In addition, USAF co-sponsored the mission to provide near real-time flux measurements for space weather awareness. First results are presented in these issues of Earth, Moon, and Planets in preparation for future missions that will target the exceptional Leonid returns of 2001 and 2002. An early review of the scientific achievements in the context of campaign objectives is given. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Moffett Field, CA USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov NR 56 TC 5 Z9 5 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 1 EP 26 DI 10.1023/A:1017020106785 PG 26 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200001 ER PT J AU Jenniskens, P Wilson, MA Packan, D Laux, CO Kruger, CH Boyd, ID Popova, OP Fonda, M AF Jenniskens, P Wilson, MA Packan, D Laux, CO Kruger, CH Boyd, ID Popova, OP Fonda, M TI Meteors: A delivery mechanism of organic matter to the early Earth SO EARTH MOON AND PLANETS LA English DT Article DE ablation; astrobiology; exobiology; meteors; meteoroids; origin of life ID INTERPLANETARY DUST; ORIGIN; LIFE; MOLECULES; ATMOSPHERE; IMPACTS; COMETS; MICROMETEORITES; EVOLUTION; VOLATILES AB All potential exogenous pre-biotic matter arrived to Earth by ways of our atmosphere, where much material was ablated during a luminous phase called "meteors" in rarefied flows of high (up to 270) Mach number. The recent Leonid showers offered a first glimpse into the clusive physical conditions of the ablation process and atmospheric chemistry associated with high-speed meteors. Molecular emissions were detected that trace a meteor's brilliant light to a 4,300 K warm wake rather than to the meteor's head. A new theoretical approach using the direct simulation by Monte Carlo technique identified the source-region and demonstrated that the ablation process is critical in the heating of the meteor's wake. In the head of the meteor, organic carbon appears to survive flash heating and rapid cooling. The temperatures in the wake of the meteor are just right for dissociation of CO and the formation of more complex organic compounds. The resulting materials could account for the bulk of pre-biotic organic carbon on the early Earth at the time of the origin of life. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Dept Mech Engn, High Temp Gasdynam Lab, Stanford, CA 94305 USA. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. RAS, Inst Dynam Geospheres, Moscow 117979, Russia. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov RI Popova, Olga/K-1885-2012 NR 52 TC 50 Z9 50 U1 0 U2 11 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 57 EP 70 DI 10.1023/A:1017017728166 PG 14 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200005 ER PT J AU Rairden, RL Jenniskens, P Laux, CO AF Rairden, RL Jenniskens, P Laux, CO TI Search for organic matter in Leonid meteoroids SO EARTH MOON AND PLANETS LA English DT Article DE astrobiology; CN; exobiology; Leonids 1999; meteors; meteoroids; origin of life; spectroscopy; ultraviolet ID DUST AB Near-ultraviolet 300-410 nm spectra of Leonid meteoroids were obtained in an effort to measure the strong B --> X emission band of the radical CN in Leonid meteor spectra at 387 nm. CN is an expected product of ablation of nitrogen containing organic carbon in the meteoroids as well as a possible product of the aerothermochemistry induced by the kinetic energy of the meteor. A slit-less spectrograph with objective grating was deployed on FISTA during the 1999 Leonid Multi-Instrument Aircraft Campaign. Fifteen first-order UV spectra were captured near the 02:00 UT meteor storm peak on November 18. It is found that neutral iron lines dominate the spectrum, with no clear sign of the CN band. The meteor plasma contains less than one CN molecule per 3 Fe atoms at the observed altitude of about 100 km. C1 Lockheed Martin Space Sci Lab, Dept L9 42, Palo Alto, CA 94304 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Stanford Univ, Dept Mech Engn, High Temp Gasdynam Lab, Stanford, CA 94305 USA. RP Rairden, RL (reprint author), Lockheed Martin Space Sci Lab, Dept L9 42, Bldg 255,3251 Hanover St, Palo Alto, CA 94304 USA. EM rairden@spasci.com; pjenniskens@mail.arc.nasa.gov; laux@saha.stanford.edu NR 16 TC 0 Z9 0 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 71 EP 80 DI 10.1023/A:1017021929075 PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200006 ER PT J AU Rossano, GS Russell, RW Lynch, DK Tessensohn, TK Warren, D Jenniskens, P AF Rossano, GS Russell, RW Lynch, DK Tessensohn, TK Warren, D Jenniskens, P TI Observations of Leonid meteors using a mid-wave infrared imaging spectrograph SO EARTH MOON AND PLANETS LA English DT Article DE ablation; Leonids 1998; meteors; meteoroids; mid-IR emission ID SHOWER AB We report broadband 3-5.5 mum detections of two Leonid meteors observed during the 1998 Leonid Multi-Instrument Aircraft Campaign. Each meteor was detected at only one position along their trajectory just prior to the point of maximum light emission. We describe the particular aspects of the Aerospace Corp. Mid-wave Infra-Red Imaging Spectrograph (MIRIS) developed for the observation of short duration transient events that impact its ability to detect Leonid meteors. This instrument had its first deployment during the 1998 Leonid MAC. We infer from our observations that the mid-wave IR light curves of two Leonid meteors differed from the visible light curve. At the points of detection, the infrared emission in the MIRIS passband was 25 +/- 4 times that at optical wavelengths for both meteors. In addition, we find an upper limit of 800 K for the solid body temperature of the brighter meteor we observed, at the point in the trajectory where we made our mid-wave IR detection. C1 Aerosp Corp, El Segundo, CA 90245 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Rossano, GS (reprint author), Aerosp Corp, M2-266,2350 E El Segundo Blvd, El Segundo, CA 90245 USA. EM george.s.rossano@aero.org; pjenniskens@mail.arc.nasa.gov NR 6 TC 1 Z9 1 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 81 EP 92 DI 10.1023/A:1017026032709 PG 12 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200007 ER PT J AU Despois, D Ricaud, P Lautie, N Schneider, N Jacq, T Biver, N Lis, DC Chamberlin, RA Phillips, TG Miller, M Jenniskens, P AF Despois, D Ricaud, P Lautie, N Schneider, N Jacq, T Biver, N Lis, DC Chamberlin, RA Phillips, TG Miller, M Jenniskens, P TI Search for extraterrestrial origin of atmospheric trace molecules - Radio sub-MM observations during the leonids SO EARTH MOON AND PLANETS LA English DT Article DE early Earth; H2O; HCN; Leonids 1999; lower thermosphere; O-3; mesosphere; meteors; micro-wave; radio ID HYDROGEN-CYANIDE HCN; STRATOSPHERE; CHEMISTRY; SHOWER AB To identify the effect of meteor showers on the molecular content of the upper atmosphere of the Earth, we have carried out ground-based observations of atmospheric HCN. HCN radio observations at CSO (Hawaii) on Nov 18/19, 1999, the night after the second Leonid shower maximum, show unusually low HCN abundances above 45 km altitude, which are only recovered after sunrise. We also investigated UARS/HALOE satellite data on H2O and O-3. No correlation appears of year round H2O and O-3 around 55 km with annual meteor showers, nor with meteor activity at the time of the 1998 Leonid shower. C1 Observ Bordeaux, F-33270 Floirac, France. Univ Hawaii, IfA, Honolulu, HI 96822 USA. Observ Paris, F-92195 Meudon, France. CALTECH, Downs Lab Phys, Pasadena, CA 91125 USA. Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Despois, D (reprint author), Observ Bordeaux, BP 89, F-33270 Floirac, France. EM despois@observ.u-bordeaux.fr NR 27 TC 0 Z9 0 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 129 EP 140 DI 10.1023/A:1017075315388 PG 12 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200010 ER PT J AU Brown, P Campbell, MD Ellis, KJ Hawkes, RL Jones, J Gural, P Babcock, D Barnbaum, C Bartlett, RK Bedard, M Bedient, J Beech, M Brosch, N Clifton, S Connors, M Cooke, B Goetz, P Gaines, JK Gramer, L Gray, J Hildebrand, AR Jewell, D Jones, A Leake, M LeBlanc, AG Looper, JK McIntosh, BA Montague, T Morrow, MJ Murray, IS Nikolova, S Robichaud, J Spondor, R Talarico, J Theijsmeijer, C Tilton, B Treu, M Vachon, C Webster, AR Weryk, R Worden, SP AF Brown, P Campbell, MD Ellis, KJ Hawkes, RL Jones, J Gural, P Babcock, D Barnbaum, C Bartlett, RK Bedard, M Bedient, J Beech, M Brosch, N Clifton, S Connors, M Cooke, B Goetz, P Gaines, JK Gramer, L Gray, J Hildebrand, AR Jewell, D Jones, A Leake, M LeBlanc, AG Looper, JK McIntosh, BA Montague, T Morrow, MJ Murray, IS Nikolova, S Robichaud, J Spondor, R Talarico, J Theijsmeijer, C Tilton, B Treu, M Vachon, C Webster, AR Weryk, R Worden, SP TI Global ground-based electro-optical and radar observations of the 1999 Leonid shower: First results SO EARTH MOON AND PLANETS LA English DT Article DE Leonids 1999; meteor; meteor flux; meteor shower; meteoroids; satellite impact hazard ID METEORS; ABLATION; DANGER AB A total of 18 image intensified CCD detectors were deployed at 6 locations (two in Negev Desert, Israel, and one in each of the Canary Islands, Long Key in Florida, Haleakala in Hawaii, and the Kwajalein Atoll) to provide a real-time reporting system, as well as data for subsequent detailed analysis, for the 1999 Leonid shower. Fields of view ranged from 9 to 34 degrees, with apparent limiting stellar magnitudes from about +7 to +9. In addition, a dual frequency (29.850 and 38.15 MHz) automated meteor radar with directional determination capability was located in the Canadian Arctic at Alert, Nunavut and provided continuous monitoring of the shower from a location where the radiant was constantly above the horizon. Both the radar and electro-optical systems successfully recorded the activity of the shower in real time, and typical real-time activity plots are presented. Post-event analysis has concentrated on the Israel electro-optical wide field cameras and the time interval centered around the peak of the storm. About 2700 meteors have been digitized, with 680 measured for this analysis. Of these 371 were well enough determined to permit a single-station technique to yield approximate heights. Light curves and photometric masses were computed for these 371 Leonids which form the basis of the preliminary results reported in this paper. These cameras recorded Leonid meteors with peak luminosity in the magnitude range -3 to +5, corresponding to the photometric mass range 10(-4) to 10(-7) kg. A regression plot of photometric mass with magnitude did not indicate any change in light curve shape over the interval studied here. The peak flux as determined by the electro-optical observations was 1.6 +/- 0.1 Leonid meteors of magnitude +6.5 or brighter falling on a one square kilometer area (oriented perpendicular to the Leonid radiant) per hour. This peak flux occurred at approximately 2:07 +/-: 06 UT on Nov 18 1999, corresponding to solar longitude lambda (o) = 235.248 (epoch 2000.0). The radar results were consistent with this maximum flux rate and time. There was not a strong change in mass distribution over the few hours around maximum, although there is some indication that the peak interval was stronger in fainter meteors. Height histograms are provided for beginning, maximum luminosity and ending heights. It was found that maximum luminosity and ending heights were completely independent of mass, consistent with a dustball model in which the meteoroids are fragmented into constituent grains prior to ablation of the grains. However, the beginning height increases sharply (9.1 km per decade of photometric mass change) with increasing mass. This is possibly indicative of a volatile component which ablates early in the atmospheric trajectory. C1 Univ Western Ontario, London, ON, Canada. Ctr Commun Res, Ottawa, ON, Canada. Mt Allison Univ, Sackville, NB E0A 3C0, Canada. Sci Applicat Int Corp, Arlington, VA USA. Valdosta State Univ, Valdosta, GA USA. Pentagon, USAF, Washington, DC USA. HQ USAF Directorate Weather, Washington, DC USA. Univ Regina, Campion Coll, Regina, SK S4S 0A2, Canada. Wise Observ, Tel Aviv, Israel. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Athabasca Univ, Athabasca, AB, Canada. USAF, HQ AFSPC DORW, Colorado Springs, CO USA. Univ Calgary, Calgary, AB, Canada. HQ USAF Space Command, Colorado Springs, CO USA. Dept Natl Def, Ottawa, ON, Canada. USAF, HQ AFSPC XPXY, Colorado Springs, CO USA. USAF, Space & Reconnaissance Requirements Div, Washington, DC 20330 USA. RP Brown, P (reprint author), Univ Western Ontario, London, ON, Canada. EM rhawkes@mta.ca RI Brosch, Noah/C-7889-2009; Gramer, Lewis/A-5620-2010 OI Gramer, Lewis/0000-0003-4772-1991 NR 28 TC 2 Z9 2 U1 1 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 167 EP 190 DI 10.1023/A:1017024802184 PG 24 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200013 ER PT J AU Jenniskens, P Crawford, C Butow, SJ Nugent, D Koop, M Holman, D Houston, J Jobse, K Kronk, G Beatty, K AF Jenniskens, P Crawford, C Butow, SJ Nugent, D Koop, M Holman, D Houston, J Jobse, K Kronk, G Beatty, K TI Lorentz shaped comet dust trail cross section from new hybrid visual and video meteor counting technique - Implications for future Leonid storm encounters SO EARTH MOON AND PLANETS LA English DT Article DE comet; comet; 55P/Tempel-Tuttle; dust trail; flux; Leonids 1999; Lorentz profile; meteor; meteor storm; predictions; satellite impact hazard; observing techniques ID STREAM ACTIVITY AB A new hybrid technique of visual and video meteor observations was developed to provide high precision near real-time flux measurements for satellite operators from airborne platforms. A total of 33,000 Leonids, recorded on video during the 1999 Leonid storm, were watched by a team of visual observers using a video head display and an automatic counting tool. The counts reveal that the activity profile of the Leonid storm is a Lorentz profile. By assuming a radial profile for the dust trail that is also a Lorentzian, we make predictions for future encounters. If that assumption is correct, we passed 0.0003 AU deeper into the 1899 trailet than expected during the storm of 1999 and future encounters with the 1866 trailet will be less intense than predicted elsewhere. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Calif Meteor Soc, San Jose, CA 95129 USA. Dutch Meteor Soc, NL-2318 NB Leiden, Netherlands. Amer Meteor Soc, N Amer Meteor Network, Troy, IL 62294 USA. Sky & Telescope, Cambridge, MA 02138 USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov NR 15 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 191 EP 208 DI 10.1023/A:1017076829926 PG 18 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200014 ER PT J AU Gural, PS Jenniskens, P AF Gural, PS Jenniskens, P TI Leonid storm flux analysis from one Leonid Mac Video AL50R SO EARTH MOON AND PLANETS LA English DT Article DE clustering; flux; fragmentation; Leonids 1999; meteor; meteoroid; optimal video pointing; satellite impact hazard; simulation AB A detailed meteor flux analysis is presented of a seventeen-minute portion of one videotape, collected on November 18, 1999, during the Leonid Multi-instrument Aircraft Campaign. The data was recorded around the peak of the Leonid meteor storm using an intensified CCD camera pointed towards the low southern horizon. Positions of meteors on the sky were measured. These measured meteor distributions were compared to a Monte Carlo simulation, which is a new approach to parameter estimation for mass ratio and flux. Comparison of simulated flux versus observed flux levels, seen between 1:50:00 and 2:06:41 UT, indicate a magnitude population index of r = 1.8 +/- 0.1 and mass ratio of s = 1.64 +/- 0.06. The average spatial density of the material contributing to the Leonid storm peak is measured at 0.82 +/- 0.19 particles per square kilometer per hour for particles of at least absolute visual magnitude +6.5. Clustering analysis of the arrival times of Leonids impacting the earth's atmosphere over the total observing interval shows no enhancement or clumping down to time scales of the video frame rate. This indicates a uniformly random temporal distribution of particles in the stream encountered during the 1999 epoch. Based on the observed distribution of meteors on the sky and the model distribution, recommendations are made for the optimal pointing directions for video camera meteor counts during future ground and airborne missions. C1 Sci Applicat Int Corp, Arlington, VA 22203 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Gural, PS (reprint author), Sci Applicat Int Corp, 4001 N Fairfax Dr,Suite 500, Arlington, VA 22203 USA. EM peter.s.gural@saic.com; pjenniskens@mail.arc.nasa.gov NR 22 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 221 EP 247 DI 10.1023/A:1017030431743 PG 27 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200016 ER PT J AU Pawlowski, JF Hebert, TT AF Pawlowski, JF Hebert, TT TI The Leonid meteors and Space Shuttle risk assessment SO EARTH MOON AND PLANETS LA English DT Article DE flux; Leonids 1999; Liquid Mirror Telescope; meteor; meteor shower; satellite impact hazard ID SHOWER AB The November 1999 Leonid meteor shower was videotaped with a low light level camera from the grounds of the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) in Houston, Texas. Additionally, observations of the Leonids were recorded both digitally with the Liquid Mirror Telescope (LMT) and with a low light level camera at the JSC Observatory near Cloudcroft, New Mexico. The tapes were analyzed using a computer-automated meteor analysis system developed at JSC. These results were used to form estimates of the Leonid mass-distribution. These estimates were compared to a Leonid mass distribution model used by NASA in risk assessment calculations associated with Space Shuttle missions. The observed data agrees favorably with the NASA model in the 0.002 to 0.02 milligram range (based upon the LMT observations) and in the 0.02 to 0.2 gram range (based upon the low light level camera observations). This comparison supports the continued use of this model. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77059 USA. RP Pawlowski, JF (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Stop SN3, Houston, TX 77059 USA. EM james.f.pawlowski1@jsc.nasa.gov; thebert@uh.edu NR 8 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 249 EP 256 DI 10.1023/A:1017046802609 PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200017 ER PT J AU Betlem, H Jenniskens, P Spurny, P Van Leeuwen, GD Miskotte, K Ter Kuile, CR Zarubin, P Angelos, C AF Betlem, H Jenniskens, P Spurny, P Van Leeuwen, GD Miskotte, K Ter Kuile, CR Zarubin, P Angelos, C TI Precise trajectories and orbits of meteoroids from the 1999 Leonid meteor storm SO EARTH MOON AND PLANETS LA English DT Article DE comet dust trial; dispersion; Leonids 1999; meteor; meteor orbit; meteor trajectory; orbital dynamics ID OUTBURST AB Photographic multi-station observations of 47 Leonid meteors are presented that were obtained from two ground locations in Spain during the 1999 meteor storm. We find an unresolved compact cluster of radiants at alpha = 153.67 +/- 0.05 and delta = 21.70 +/- 0.05 for a mean solar longitude of 235.282 (J2000). The position is identical to that of the Nov. 17/18 outburst of 1998, which implies that both are due to comet 55P/Tempel-Tuttle's ejecta from 1899. We also find a halo which contains about 28% of all meteors. The spatial distribution of radiant positions appears to be Lorentzian, with a similar fraction of meteors in the profile wings as the meteor storm activity curve. C1 Dutch Meteor Soc, NL-2318 NB Leiden, Netherlands. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Ondrejov Observ, Inst Astron, Ondrejov 25165, Czech Republic. Fremont Peak Observ Assoc, San Juan Bautista, CA 95045 USA. RP Betlem, H (reprint author), Dutch Meteor Soc, Lederkarper 4, NL-2318 NB Leiden, Netherlands. EM betlem@strw.leidenuniv.nl; pjenniskens@mail.arc.nasa.gov RI Spurny, Pavel/G-9044-2014 NR 11 TC 3 Z9 3 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 277 EP 284 DI 10.1023/A:1017070313938 PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200020 ER PT J AU Jenniskens, P Nugent, D Tedesco, E Murthy, J AF Jenniskens, P Nugent, D Tedesco, E Murthy, J TI 1997 Leonid shower from space SO EARTH MOON AND PLANETS LA English DT Article DE flux; Leonids 1999; meteors; meteor shower; MSX; population index; space ID COMET TEMPEL-TUTTLE AB In November 1997, the Midcourse Space Experiment satellite (MSX) was deployed to observe the Leonid shower from space. The shower lived up to expectations, with abundant bright fireballs. Twenty-nine meteors were detected by a wide-angle, visible wavelength, camera near the limb of the Earth in a 48-minute interval, and three meteors by the narrow field camera. This amounts to a meteoroid influx of 5.5 +/- 0.6 10(-5) km(-2) hr(-1) for masses > 0.3 gram. The limiting magnitude for limb observations of Leonid meteors was measured at M-v = -1.5 magn. The Leonid shower magnitude population index was 1.6 +/- 0.2 down to M-v = -7 magn., with no sign of an upper mass cut-off. C1 NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. TerraSyst Inc, Space Sci Res Div, Lee, NH 03824 USA. Johns Hopkins Univ, Dept Phys & Astron, Appl Phys Lab, Baltimore, MD 21218 USA. RP Jenniskens, P (reprint author), NASA, SETI Inst, ARC, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov; etedesco@TerraSys.com; murthy@iiap.ernet.in NR 11 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 305 EP 312 DI 10.1023/A:1017034815755 PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200023 ER PT J AU Rietmeijer, FJM Nuth, JA AF Rietmeijer, FJM Nuth, JA TI Collected extraterrestrial materials: Constraints on meteor and fireball compositions SO EARTH MOON AND PLANETS LA English DT Article DE asteroid; bolide; chemistry; comet; cosmic dust; fireball; interplanetary dust particle (IDP); meteorite; meteor; mineralogy ID INTERPLANETARY DUST PARTICLES; COSMIC DUST; COMETARY NUCLEI; HALLEY DUST; MICROMETEORITES; MODEL; POROSITY; DISTRIBUTIONS; STRATOSPHERE; MINERALOGY AB The bulk density and bulk porosity of IDPs and various meteorite classes show that protoplanet accretion and evolution were arrested at different stages as a function of parent body modification. The collected IDPs, micrometeorites and meteorites are aggregates of different structural entities that were inherited from the earliest times of solar system evolution. These structural entities and the extent of parent body lithification will determine the material strength of the meteoroids entering the Earth's atmosphere. There is a need for measurements of the material strength of collected extraterrestrial materials because they will in part determine the nature of the chemical interactions of descending meteors and fireballs in the atmosphere. High-precision determinations of meteor and fireball compositions are required to search for anhydrous, carbon-rich proto-CI material that has survived in the boulders of comet nuclei. C1 Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rietmeijer, FJM (reprint author), Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. EM fransjmr@unm.edu; uljan@lepvax.gsfc.nasa.gov RI Nuth, Joseph/E-7085-2012 NR 60 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 325 EP 350 DI 10.1023/A:1017086517630 PG 26 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200025 ER PT J AU Murray, IS Beech, M Taylor, MJ Jenniskens, P Hawkes, RL AF Murray, IS Beech, M Taylor, MJ Jenniskens, P Hawkes, RL TI Comparison of 1998 and 1999 Leonid light curve morphology and meteoroid structure SO EARTH MOON AND PLANETS LA English DT Article DE comets; dust; Leonids 1999; lightcurves; meteoroids; meteors ID SHOWER AB Photometric low-light level video observations of 1999 Leonid storm meteors have been obtained from two airborne platforms during the Leonid multi-instrument aircraft campaign (Leonid MAC). The 1999 Leonid light curves tend to be skewed towards the end point of the trajectory, while the 1998 Leonid light curves were not. The variation in the light curves from 1998 and 1999 can be explained as an overall reduction in the mass distribution index, alpha from similar to 1.95 in 1998 to similar to 1.75 in 1999. We have interpreted this behaviour as being either indicative of a gradual loss of the "glue" that keeps the grains together, or the fact that the meteoroids sampled in 1998 had a different morphological structure to those sampled in 1999. The early fragmentation of a dustball meteoroid results in a light curve that peaks sooner than that predicted by classical single body ablation theory. C1 Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada. Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. Mt Allison Univ, Dept Phys, Sackville, NB E4L 1E6, Canada. RP Murray, IS (reprint author), Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada. EM murrayli@mail.uregina.ca NR 28 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 351 EP 367 DI 10.1023/A:1017003019448 PG 17 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200026 ER PT J AU Taylor, MJ Gardner, LC Murray, IS Jenniskens, P AF Taylor, MJ Gardner, LC Murray, IS Jenniskens, P TI Jet-like structures and wake in MgI (518 nm) images of 1999 Leonid storm meteors SO EARTH MOON AND PLANETS LA English DT Article DE fragmentation; jet-like; Leonids 1999; meteoroids; meteors; structures; wake AB Small meteoric fragments are ejected at significant transverse velocities from some (up to similar to8%) fast Leonid meteors. We reach this conclusion using low light intensified image measurements obtained during the 1999 Leonid Multi-Instrument Aircraft Campaign. High spatial resolution, narrow band image measurements of the Mg I emission at 518 nm have been used to clearly identify jet-like features in the meteor head that are the same as first observed in white light by LeBlanc et al. (1999). We postulate that these unusual structures are caused by tiny meteoroid fragments (containing metallic grains) being rapidly ejected away from the core meteoroid as the constituent glue evaporates. Marked curvature observed in the jet-like filaments suggest that the parent meteoroids are spinning and as the whirling fragments are knocked away by the impinging air molecules, or by grain-grain collisions in the fragment ensemble, they ablate quickly generating an extended area of structured luminosity up to about 1-2 km from the meteoroid center. Fragments with smaller transverse velocity components are thought to be responsible for the associated beading evident in the wake of these unusual Leonid meteors. C1 Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. Utah State Univ, Dept Phys, Logan, UT 84322 USA. Univ Regina, Dept Phys, Regina, SK S4S 0A2, Canada. NASA, SETI Inst, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Taylor, MJ (reprint author), Utah State Univ, Space Dynam Lab, Logan, UT 84322 USA. EM mtaylor@cc.usu.edu; murray1i@mail.uregina.ca; pjenniskens@mail.arc.nasa.gov NR 15 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 379 EP 389 DI 10.1023/A:1017063322173 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200028 ER PT J AU Borovicka, J Jenniskens, P AF Borovicka, J Jenniskens, P TI Time resolved spectroscopy of a Leonid fireball afterglow SO EARTH MOON AND PLANETS LA English DT Article DE afterglow; debris; dust; H; meteor; persistent train; spectroscopy ID SPECTRA; METEORS AB Two video spectra of a meteoric afterglow were obtained for the first time during the 1999 Leonid aircraft campaign. The train was produced by a -13 magnitude Leonid fireball at a relatively low height between 91-75 km. The meteor spectrum has a strong hydrogen emission, proportional to 10-20 II atoms per one Fe atom The train spectrum consisted of a red continuum, yellow continuum, and about 50 atomic lines between 3700-9000 Angstrom. The yellow continuum, possibly due to NO2, was also detected in the persistent train. The red continuum is interpreted as a thermal radiation of dust from meteoric debris at about 1400 K. Evidence for secondary ablation is found in the afterglow. The atomic lines decayed within seconds of the meteor. The lines of Fe I, Mg I, Na I, Ca I, Ca II, Cr I, Mn I, K I, and possibly Al I were present in the glow together with the 5577 Angstrom forbidden O I line. The gas temperature in the train was close to 5000 K at the beginning and decayed to 1200 K within two seconds. However, thermal equilibrium was not satisfied for all populated levels. C1 Ondrejov Observ, Astron Inst, Ondrejov 25165, Czech Republic. NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. RP Borovicka, J (reprint author), Ondrejov Observ, Astron Inst, Ondrejov 25165, Czech Republic. EM borovic@asu.cas.cz; pjenniskens@mail.arc.nasa.gov RI Borovicka, Jiri/F-4257-2014 NR 21 TC 12 Z9 12 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 399 EP 428 DI 10.1023/A:1017071524899 PG 30 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200030 ER PT J AU Jenniskens, P Lacey, M Allan, BJ Self, DE Plane, JMC AF Jenniskens, P Lacey, M Allan, BJ Self, DE Plane, JMC TI FeO "Orange arc" emission detected in optical spectrum of Leonid persistent train SO EARTH MOON AND PLANETS LA English DT Article DE airglow; FeO; Leonids 1999; mesosphere; meteors; persistent train AB We report the detection of a broad continuum emission dominating the visual spectrum of a Leonid persistent train. A comparison with laboratory spectra of FeO "orange arc" emission at 1 mbar shows a general agreement of the band position and shape. The detection of FeO confirms the classical mechanism of metal atom catalyzed recombination of ozone and oxygen atoms as the driving force behind optical emission from persistent trains. Sodium and iron atoms are now confirmed catalysts. C1 NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. RP Jenniskens, P (reprint author), NASA, SETI Inst, ARC, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov; J.Plane@uea.ac.uk RI Allan, Beverley/H-5437-2011; Plane, John/C-7444-2015 OI Plane, John/0000-0003-3648-6893 NR 12 TC 8 Z9 8 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 429 EP 438 DI 10.1023/A:1017079725808 PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200031 ER PT J AU Russell, RW Rossano, GS Chatelain, MA Lynch, DK Tessensohn, TK Abendroth, E Kim, D Jenniskens, P AF Russell, RW Rossano, GS Chatelain, MA Lynch, DK Tessensohn, TK Abendroth, E Kim, D Jenniskens, P TI Mid-infrared spectroscopy of persistent Leonid trains SO EARTH MOON AND PLANETS LA English DT Article DE meteors; meteoroids; mid-IR spectroscopy; persistent trains ID LIDAR AB The first infrared spectroscopy in the 3-13 micron region has been obtained of several persistent Leonid meteor trains with two different instrument types, one at a desert ground-based site and the other on-board a high-flying aircraft. The spectra exhibit common structures assigned to enhanced emissions of warm CH4, CO2, CO and H2O, which may originate from heated trace air compounds or materials created in the wake of the meteor. This is the first time that any of these molecules has been observed in the spectra of persistent trains. Hence, the mid-IR observations offer a new perspective on the physical processes that occur in the path of the meteor at some time after the meteor itself has passed by. Continuum emission is observed also, but its origin has not yet been established. No 10 micron dust emission feature has been observed. C1 Aerosp Corp, Space Sci Applicat Lab, Los Angeles, CA 90009 USA. NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. RP Russell, RW (reprint author), Aerosp Corp, Space Sci Applicat Lab, M2-266,POB 92957, Los Angeles, CA 90009 USA. EM Ray.W.Russell@aero.org NR 13 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 439 EP 456 DI 10.1023/A:1017083811695 PG 18 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200032 ER PT J AU Jenniskens, P Rairden, RL AF Jenniskens, P Rairden, RL TI Buoyancy of the "Y2K" persistent train and the trajectory of the 04 : 00 : 29 UT Leonid fireball SO EARTH MOON AND PLANETS LA English DT Article DE fireball; Leonids 1999; lower thermosphere; mesosphere; meteor; persistent train; winds AB The atmospheric trajectory is calculated of a particularly well studied fireball and train during the 1999 Leonid Multi-Instrument Aircraft Campaign. Less than a minute after the meteor's first appearance, the train curves into a "2"-shape, which persisted until at least 13 minutes after the fireball. We conclude that the shape results because of horizontal winds from gravity waves with a scale height of 8.3 km at 79-91 km altitude, as well as a westerly wind gradient with altitude. In addition, there is downward drift that affects the formation of loops in the train early on. C1 NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. Lockheed Martin Space Sci Lab, Dept L9 42, Palo Alto, CA 94304 USA. RP Jenniskens, P (reprint author), NASA, SETI Inst, ARC, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov; rairden@spasci.com NR 10 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 457 EP 470 DI 10.1023/A:1017044229442 PG 14 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200033 ER PT J AU Jenniskens, P Nugent, D Plane, JMC AF Jenniskens, P Nugent, D Plane, JMC TI The dynamical evolution of a tubular Leonid persistent train SO EARTH MOON AND PLANETS LA English DT Article DE airglow; chemistry; dynamics; Leonids 1998; lower thermosphere; mesosphere; meteor; persistent train ID UPPER-ATMOSPHERE; SODIUM; CHEMISTRY AB The dynamical evolution of the persistent train of a bright Leonid meteor was examined for evidence of the source of the luminosity and the physical conditions in the meteor path. The train consisted of two parallel somewhat diffuse luminous tracks, interpreted as the walls of a tube. A general lack of wind shear along the trail allowed these structures to remain intact for nearly 200 s, from which it was possible to determine that the tubular structure expanded at a near constant 10.5 ms(-)1, independent of altitude between 86 and 97 km. An initial fast decrease of train intensity below 90 km was followed by an increase in intensity and then a gradual decrease at longer times, whereas at high altitudes the integrated intensity was nearly constant with time. These results are compared to a model that describes the dynamical evolution of the train by diffusion, following an initial rapid expansion of the hot gaseous trail behind the meteoroid. The train luminosity is produced by O (S-1) emission at 557 nm, driven by elevated atomic O levels produced by the meteor impact, as well as chemiluminescent reactions of the ablated metals Na and Fe with O-3. Ozone is rapidly removed within the train, both by thermal decomposition and catalytic destruction by the metallic species. Hence, the brightest emission occurs at the edge of the train between outwardly diffusing metallic species and inwardly diffusing O-3. Although the model is able to account plausibly for a number of characteristic features of the train evolution, significant discrepancies remain that cannot casily be resolved. C1 NASA, SETI Inst, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. RP Jenniskens, P (reprint author), NASA, SETI Inst, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM pjenniskens@mail.arc.nasa.gov; J.Plane@uea.ac.uk RI Plane, John/C-7444-2015 OI Plane, John/0000-0003-3648-6893 NR 26 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 471 EP 488 DI 10.1023/A:1017000414421 PG 18 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200034 ER PT J AU Rietmeijer, FJM Jenniskens, P AF Rietmeijer, FJM Jenniskens, P TI Recognizing Leonid meteoroids among the collected stratospheric dust SO EARTH MOON AND PLANETS LA English DT Article DE ablation; chemical composition; comets; cosmic dust; Leonids; interplanetary dust particles (IDPs); meteor showers; silicates; spheres ID STREAM ACTIVITY; EARTHS ATMOSPHERE; PARTICLES; MINERALOGY AB Three chemical groups of primary "silicate" spheres < 30 mum in diameter of cometary origin were collected in the lower stratosphere between 1981 May and 1994 July. The "silicate" sphere abundances represent an annual background from contributions by sporadic meteor and weak annual meteor shower activities. During two collection periods, from 06/22 until 08/18, 1983 (U2015), and from 09/15-12/15, 1981 (W7027/7029), a higher number of spheres was collected compared to other periods of the year represented by the other collectors studied here. This study links two different data sets, viz. the NASSA/JSC Cosmic Dust Catalogs and peak activities of annual meteor showers, and identified high-velocity cometary sources for collected stratospheric "silicate" spheres. The majority of spheres on flag U2015 may originate from comet P/Swift-Tuttle (Perseids), while the majority of spheres on flags W7027/7029 could be from comet P/Halley (Orionids) or comet P/Tempel-Tuttle (Leonids). Variations in relative proportions of the Mg,Si,Ca +/- Al, Mg,Si +/- Fe and Al, Si,Ca spheres may offer a hint of chemical differences among high-velocity comets. Proof for the findings reported here might be obtained by targeted cosmic dust collections in the lower stratosphere including periods of meteor shower and storm activity. C1 Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. NASA, SETI Inst, ARC, Moffett Field, CA 94035 USA. RP Rietmeijer, FJM (reprint author), Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. EM fransjmr@unm.edu; pjenniskens@mail.arc.nasa.gov NR 36 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 82-3 BP 505 EP 524 DI 10.1023/A:1017008600309 PG 20 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 372TM UT WOS:000165250200036 ER PT J AU Boss, AP Beichman, CA Thronson, HA AF Boss, AP Beichman, CA Thronson, HA TI NASA and the search for extrasolar planets SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT Conference on Extrasolar Planets - Formation, Detection, and Modelling CY APR 27-MAY 01, 1998 CL LISBON, PORTUGAL SP Univ Lisbon, Univ lisboa, Ctr Fis Nucl, Observ Astron Lisboa, Fdn Ciencia & Technol, Univ Lisboa, Fdn Fac Ciencias, Paris Observ, European Union Euroconference C1 Carnegie Inst Washington, Washington, DC 20015 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA Hheadquarters, Washington, DC 20546 USA. RP Boss, AP (reprint author), Carnegie Inst Washington, 5241 Broad Branch Rd NW, Washington, DC 20015 USA. RI Thronson, Harley/E-3382-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 81 IS 1 BP 35 EP 38 DI 10.1023/A:1006380328814 PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291NB UT WOS:000085742000007 ER PT J AU Cruikshank, DP AF Cruikshank, DP TI Laboratory astrophysics in solar system studies - An overview SO EARTH MOON AND PLANETS LA English DT Review ID INTERPLANETARY DUST PARTICLES; NEAR-INFRARED SPECTROSCOPY; KUIPER BELT; OPTICAL-CONSTANTS; ORGANIC-MATTER; MU-M; REFLECTANCE SPECTROSCOPY; THERMAL EMISSION; TITANS SURFACE; WATER-ICE AB The compositions of the numerous bodies in the Solar System are determined from remote sensing observations, most often spectroscopic, and in some cases direct sampling. Laboratory studies of materials and processes are an essential component of the analysis and interpretation of all compositional data. Planetary atmospheres are composed of gases and aerosols, while the surfaces of the terrestrial planets, asteroids, comets, and planetary satellites are composed of minerals, ices, and organic solids. The principal spectroscopic characteristics of each of these materials are reviewed here. The tables present a synopsis of our current knowledge of the compositions of the principal bodies in the Solar System. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM dale@ssa1.arc.nasa.gov NR 135 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 80 IS 1-3 BP 3 EP 33 DI 10.1023/A:1006320609295 PG 31 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291HB UT WOS:000085727100002 ER PT J AU Bernstein, MP AF Bernstein, MP TI Water ice on comets and satellites SO EARTH MOON AND PLANETS LA English DT Article ID HALE-BOPP; INTERSTELLAR ICES; ASTROPHYSICAL IMPLICATIONS; DUST PARTICLES; SOLAR NEBULA; HYAKUTAKE; ANALOGS; HALLEY; MOLECULE; ORIGIN AB This brief overview will cover some recent work on solar system ices. The focus is on the origin, physical properties, composition, and radiation-induced chemistry of ices dominated by water, with an emphasis on comets and water-rich ices on satellites such as Europa. Understanding the physical characteristics and chemistry of these ices is important for explaining observations such as the albedo and sublimation of ice from planetesimals and comets, the formation of molecules that may have led to life, and planning present and future space missions. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Bernstein, MP (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 75 TC 1 Z9 1 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 80 IS 1-3 BP 35 EP 50 DI 10.1023/A:1006301526134 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291HB UT WOS:000085727100003 ER PT J AU Nuth, JA Hallenbeck, SL Rietmeijer, FJM AF Nuth, JA Hallenbeck, SL Rietmeijer, FJM TI Interstellar and interplanetary grains - Recent developments and new opportunities for experimental chemistry SO EARTH MOON AND PLANETS LA English DT Review ID DUST PARTICLES; INFRARED-SPECTROSCOPY; SIZE DISTRIBUTIONS; OXYGEN ISOTOPES; SILICATE GRAINS; METEORITES; EMISSION; SPECTRA; MINERALOGY; EXTINCTION C1 NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. RP Nuth, JA (reprint author), NASA, Goddard Space Flight Ctr, Astrochem Branch, Code 691, Greenbelt, MD 20771 USA. RI Nuth, Joseph/E-7085-2012 NR 105 TC 18 Z9 18 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 80 IS 1-3 BP 73 EP 112 DI 10.1023/A:1006305627042 PG 40 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291HB UT WOS:000085727100005 ER PT J AU Jenniskens, P de Lignie, M Betlem, H Borovicka, J Laux, CO Packan, D Kruger, CH AF Jenniskens, P de Lignie, M Betlem, H Borovicka, J Laux, CO Packan, D Kruger, CH TI Preparing for the 1998/99 Leonid storms SO EARTH MOON AND PLANETS LA English DT Article DE meteoroids; comets; atmosphere; dynamics; organic chemistry ID METEOR STREAM ACTIVITY; COMET TEMPEL-TUTTLE; FIREBALL SPECTRUM; OUTBURST; EARTH AB In order to further observing programs aimed at the possible meteor storms of November 1998 and 1999, we describe here how the Leonid shower is expected to manifest itself on the sky. We discuss: 1) the expected wavelength dependence of meteor (train) emission, 2) the meteor brightness distribution and influx, 3) the stream cross section, radiant and altitude of the meteors, 4) the apparent fluxes at various positions in the sky as a function of radiant elevation as well as 5) the trail length and radial velocity, and 6) the diameter and brightness of persistent trains as a function of radiant elevation. These topics were chosen to help researchers plan an observing strategy for imaging, spectroscopy, and LIDAR observations. Some applications are discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Dutch Meteor Soc, NL-2318 NB Leiden, Netherlands. Astron Inst, Ondrejov 25165, Czech Republic. Stanford Univ, Dept Mech Engn, High Temp Gasdynam Lab, Stanford, CA 94305 USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM peter@max.arc.nasa.gov; betlem@strw.LeidenUniv.nl; borovic@asu.cas.cz; laux@saha.stanford.edu RI Borovicka, Jiri/F-4257-2014 NR 41 TC 20 Z9 21 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1998 VL 80 IS 1-3 BP 311 EP 341 DI 10.1023/A:1006338501543 PG 31 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291HB UT WOS:000085727100013 ER PT S AU Markham, BL Barker, JL Pedelty, JA Gorin, I Kaita, E AF Markham, BL Barker, JL Pedelty, JA Gorin, I Kaita, E BE Barnes, WL TI Pre-launch performance of the Landsat-7 enhanced Thematic Mapper plus SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE Landsat-7; ETM+; radiometry; linearity; spectral response; noise; internal calibrator AB Landsat-7 will carry the Enhanced Thematic Mapper Plus (ETM+) as its payload This instrument is a derivative of the Thematic Mapper (TM) instruments flown on the Landsat 4 and 5 spacecraft. Rey changes to the instrument include a new 15 meter panchromatic band, a higher spatial resolution thermal band and two new solar calibrators to improve the radiometric calibration of the reflective bands. The ETM+ went through its baseline ambient radiometric and geometric calibration tests during the summer of 1997 and began environmental testing in the fall of 1997. The ETM+ suffered a power supply failure during the initial thermal vacuum testing during late 1997 to early 1998. Since the power supply repair was completed in May 1998, the ETM+ has been going through a series of radiometric performance tests to recharacterize noise, linearity, radiometric stability, aml absolute radiometric calibration in ambient and is currently preparing to enter thermal vacuum testing. Spectral and radiometric test results from the current and previous tests are presented and compared. System spectral responsivity, based on component level measurements, is similar to previous TM instruments. One notable difference is in band 5, where the ETM+ response cuts off neat the nominal value of 1.75 mu m versus the 1.78 mu m of Landsat 4 and 5 TM's, providing a bandpass freer of atmospheric absorption. The pre-power supply repair noise results showed inspecification performance for all bands except the panchromatic band, which showed 104 kHz noise. The overall noise level in the panchromatic band was up to 11 counts (standard deviation). After the power supply repair, which involved replacement of 108 diodes in each power supply, the overall noise in the panchromatic band was between 2 and 3 counts and was largely random. During the ETM+ testing a radiometer monitors the output of the integrating sphere used to calibrate the instrument. Use of this Landsat Transfer Radiometer (LXR) has demonstrated ETM+ linearity and provided a precision of the radiometric calibration of the ETM+ to better than the 0.1% level. The ETM+ internal calibrator (IC) has shown an instability over time at up to the 15% level. The reason for the instability is currently being investigated. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Markham, BL (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 0 TC 5 Z9 5 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 40 EP 48 DI 10.1117/12.325665 PG 9 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700005 ER PT S AU Atlas, R AF Atlas, R BE Barnes, WL TI Experiments to determine the requirements for lidar wind profile data from space SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE lidar; wind; weather; remote sensing AB Global wind profiles are needed for a wide range of meteorological applications. Since the 1980's, observing system simulation experiments have been conducted in order to evaluate the potential impact of space-based wind profiler data on numerical weather prediction, and to evaluate trade-offs in lidar design. These experiments indicated tremendous potential for satellite lidar observations to improve atmospheric analyses and forecasts. More recent experiments are aimed at assessing the precise requirements for space-based lidar wind profile data and to evaluate the potential for alternative technologies. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Atlas, R (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 910-4, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 79 EP 89 DI 10.1117/12.325615 PG 11 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700009 ER PT S AU Montgomery, H Che, NZ Bowser, J AF Montgomery, H Che, NZ Bowser, J BE Barnes, WL TI Determination of the spatial characteristics by using the Spectro-Radiometric Calibration Assembly (SRCA) of MODIS (Part 1. Along-scan) SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE remote sensing; spatial calibration; focal plane co-registration AB The Spectro-Radiometric Calibration Assembly (SRCA) is briefly described. This paper discusses one of the SRCA functions - spatial calibration to determine the channel (detector) position shift along-scan (part I). The band centroid (of all of the detectors in a band) shift along-track will be discussed in Part II (a separate paper). Discussion in this part mainly focuses on the algorithm, the methodology, and the stability of the calibration signals. The algorithm and the methodology includes: a model of the image motion as a function of data sample and the centroid calculation to determine the detector/band positions. The SRCA stability is examined by checking the data inconsistencies between redundant samples, sub-samples, and the two mirror sides. Also described is the handling of the dark-reading for the thermal bands, which is affected by background energy from the opaque part of the reticle. A series of results are presented, which compare the relative position shift and co-registration between channels, bands, and Focal Plane Assemblies(FPAs). Test results are illustrated for calibration under different environments and by different instruments. These results indicate that the SRCA is a stable and sensitive calibrator which provides consistent results. The overall uncertainty analysis will be presented in Part II. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Montgomery, H (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 14 Z9 14 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 226 EP 237 DI 10.1117/12.325628 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700021 ER PT S AU Montgomery, H Che, NZ Bowser, J AF Montgomery, H Che, NZ Bowser, J BE Barnes, WL TI Determination of the spatial characteristics by using the Spectro-Radiometric Calibration Assembly (SRCA) of MODIS (Part II. Along-track) SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE remote sensing; spatial calibration; focal plane co-registration AB This paper discusses the SRCA spatial calibration for the band centroid shift along-track, It is the second part of spatial calibration, which is for along-track. Next is a discussion of the linear range of weighted Y, which is the moment arm in the centroid computation, and the effect of MODIS/SRCA magnification change on the Y value. Also described is the relative calibration between channels to eliminate the weight from non-uniform response of channels to the centroid Y. Results are presented for calibration under different environments and by different instruments. An overall summary of uncertainty sources and spatial calibration accuracy are presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20721 USA. RP Montgomery, H (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20721 USA. NR 0 TC 13 Z9 13 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 238 EP 246 DI 10.1117/12.325629 PG 9 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700022 ER PT S AU Smith, GL Lee, RB Barkstrom, BR Wielicki, BA Priestley, KJ Thomas, S Paden, J Wilson, RS Pandy, DK Thornhill, KL AF Smith, GL Lee, RB Barkstrom, BR Wielicki, BA Priestley, KJ Thomas, S Paden, J Wilson, RS Pandy, DK Thornhill, KL BE Barnes, WL TI Overview of CERES sensors and in-flight performance SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE radiometry; climate; Earth Radiation Budget AB The Clouds and Earth Radiant Energy System (CERES) instrument is designed to measure the Earth's radiation budget and also to make measurements from which the anisotropy of reflected solar radiation can be computed. The instrument design, which is based on the Earth Radiation Budget Experiment (ERBE), and its operations are described. The instrument can scan in elevation and azimuth simultaneously. The azimuthal rotation is important for gathering data to describe the anisotropy of the reflected solar radiance field. The ground vacuum calibration facility ties the calibration of the instrument to the International Temperature Scale of 1990 (ITS-90). In-flight calibration sources are included to maintain and demonstrate the required 1% accuracy of each mission. Flight operations to achieve the accuracy are also discussed. The CERES Proto-Flight Model is flying on the Tropical Rainfall Measurement Mission spacecraft and successive models are scheduled to fly aboard the Earth Observation System EOS/AM-1 and EOS/PM-1 platforms. The objectives of each flight of the instrument are discussed. C1 Virginia Polytech Inst & State Univ, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, GL (reprint author), Virginia Polytech Inst & State Univ, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 292 EP 302 DI 10.1117/12.325635 PG 11 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700027 ER PT S AU Priestley, KJ Lee, RB Barkstrom, BR Thomas, S Thornhill, KL Paden, J Pandey, DK Wilson, RS Bitting, HC Smith, GL AF Priestley, KJ Lee, RB Barkstrom, BR Thomas, S Thornhill, KL Paden, J Pandey, DK Wilson, RS Bitting, HC Smith, GL BE Barnes, WL TI Radiometric stability of the Clouds and the Earth's Radiant Energy System scanning thermistor bolometer radiometers SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE CERES; TRMM; EOS; radiometry; calibration AB Each Clouds and the Earth's Radiant Energy System (CERES) instrument contains three scanning thermistor bolometer radiometric channels. These channels measure broadband radiances in the shortwave (0.3 - 5.0 mu m), total (0.3 - >100 Gun) and 8 - 12 mu m water vapor window regions. Ground-based radiometric calibration of CERES instruments is conducted by TRW, Redondo Beach, CA using their state of the art Radiometric Calibration Facility (RCF). Among the many features of the RCF are longwave and shortwave calibration systems. RCF blackbodies tied to the International Temperature Scale of 1990( ITS'90) are used for longwave calibrations. A unique Shortwave Reference Source (SWRS) allows calibration in the 0.4 to 2.0 mu m region. Additionally, a cryogenically cooled Transfer Active Cavity Radiometer (TACR) allows the transfer of the RCF longwave blackbody source calibration onto the shortwave RCF source. The CERES Internal Calibration Module (ICM) contains blackbody sources for the Total and Window radiometric channels and an evaporated quartz-tungsten lamp for the Shortwave channel. The ICM sources are used to monitor the radiometric stability of the CERES instruments over their lifetime. C1 NASA, Langley Res Ctr, Atmospher Sci Div, Hampton, VA 23681 USA. RP Priestley, KJ (reprint author), NASA, Langley Res Ctr, Atmospher Sci Div, MS 420, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 303 EP 314 DI 10.1117/12.325636 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700028 ER PT S AU Chapman, JJ AF Chapman, JJ BE Barnes, WL TI A benchtop instrument simulator for CERES/EOS-AM1 SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE software; simulation; satellite; microprocessor; virtual; instrument AB The first CERES instrument was launched on NASA/NASDA's Tropical Rainfall Measurement Mission (TRMM) platform Nov. 28, 1997. More CERES instruments will soon be launched on NASA's Earth Observing System (EOS) satellites. CERES measures top of the atmosphere radiative fluxes using microprocessor controlled scanning radiometers. The CERES EOS-AMI Instrument Simulator will serve as a testbed for the testing of custom instrument commands intended to solve in-flight anomalies of the instruments which could arise during the CERES EOS-AM1 mission. The concept of using an identical but non-flight qualified microprocessor and electronics ensemble linked to a virtual instrument PC running modelling software results in a relatively inexpensive simulation system capable of high fidelity. The first CERES Instrument Simulator resembles the TRMM CERES instrument sufficiently well to allow benchtop testing and functional verification of microprocessor loads for TRMM instrument uploads, accurate right down to the actual checksum. Each version of the CERES Instrument Simulator consists of electronic circuitry identical to the flight unit's twin microprocessors and telemetry interface to the supporting spacecraft electronics and two personal computers (PC) connected to the I/O ports that control azimuth and elevation gimbals. Flight simulation software consists of the unmodified TRW developed Plight Code and Ground Support Software specific to the platform under study which serves as the instrument monitor and also links NASA/TRW developed engineering models of the,gimballed instrument. The CERES engineering development software models were modified to provide a virtual instrument running in real-time on a second PC linked to the flight microprocessors instrument control ports. The cost of the electronics and development of such a simulation system is dwarfed by the cost to develop the actual flight software, which has already been invested in building the actual instrument. Thus for the simulator, flight soft ware re-use is very cost effective. The concept of using dedicated electronics and specific flight software matched to the instrument being studied allows for high fidelity simulations of each instrument system. The differences in flight code that represent the final flight configurations from platform to platform are accurately modeled. The overall task of tailoring the simulation system hardware to a given instrument platform reduces to the art of interfacing and programming a pair of embedded microprocessors linked to a pair of commercially available PCs. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Chapman, JJ (reprint author), NASA, Langley Res Ctr, 21 Langley Blvd MS 423, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 355 EP 366 DI 10.1117/12.325641 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700033 ER PT S AU Currey, C Smith, L Neely, B AF Currey, C Smith, L Neely, B BE Barnes, WL TI Evaluation of Clouds and the Earth's Radiant Energy System (CERES) scanner pointing accuracy using a coastline detection system SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE CERES; VIRS; geolocation; radiometer; validation; coastlines AB Clouds and the Earth's Radiant Energy System (CERES) is a National Aeronautics and Space Administration (NASA) investigation to examine the role of clouds in the radiative energy flow through the Earth-atmosphere system. The first CERES scanning radiometer was launched on November 27, 1997 into a 35 degrees inclination, 350 km altitude orbit, on the Tropical Rainfall Measuring Mission (TRMM) spacecraft. The CERES instrument consists of a three channel scanning broadband radiometer. The spectral bands measure shortwave (0.3 - 5 mu m), window (8 - 12 mu m), and total (0.3 - 100 mu m) radiation reflected or emitted from the Earth-atmosphere system. Each Earth viewing measurement is geolocated to the Earth fixed coordinate system using satellite ephemeris, Earth rotation and,geoid, and instrument pointing data. The interactive CERES coastline detection system is used to assess the accuracy of the CERES geolocation process. By analyzing radiative flux gradients at the boundaries of ocean and land masses, the accuracy of the scanner measurement locations may be derived for the CERES/TRMM instrument/satellite system. The resulting CERES measurement location errors are within 10% of the nadir footprint size. Precise pointing knowledge of the Visible and Infrared Scanner (VIRS) is required for convolution of cloud properties onto the CERES footprint; initial VIRS coastline results are included. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Currey, C (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 367 EP 376 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700034 ER PT S AU Lee, RB Wilson, RS AF Lee, RB Wilson, RS BE Barnes, WL TI Validation of 1985-1997 active cavity radiometer spacecraft measurements of total solar irradiance variability SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE radiometry; calibration; total solar irradiance; climate AB Since 1978, long-term variations in the total solar irradiance (solar constant) have been monitored using spacecraft radiometers, at the 0.01% precision level. The irradiance measurements were performed from the Earth Radiation Budget Satellite [ERBS], Nimbus-7, Solar Maximum Mission [SMM], Upper Atmosphere Research Satellite [UARS], European Retrievable Carrier (EURECA), Solar and Heliospheric Observatory [SOHO], and the Space Shuttle Atmospheric Laboratory for Applications and Science [ATLAS] spacecraft platforms. Radiometer responses can drift or shift at precision levels of a few hundreds of a percent. In-flight calibration sources are not available to detect radiometer response changes at radiometric accuracy or precision levels near the 0.01% (0.1 Wm(-2)) level. Inconsistent trends among the sets were used to : identify possible instrumental drifts or shifts which may be incorrectly interpreted as solar irradiance changes while consistent trends among the different measurement sets were used to detect long-term irradiance variability components. In this paper, 1991-1998 corresponding ERBS, UARS, SOHO, and ATLAS irradiance measurements are inter-compared with each other as well as with the ERBS empirical irradiance fit. The empirical irradiance fit is based upon 10.7-cm solar radio flux (F10) and photometric sunspot index (PSI), indices of solar magnetic activity. Analyses of recent data sets identified no long-term shifts and drifts in the ERBS, SOHO, or UARS data sets. The typical value of the total solar irradiance is approximately 1365 Watts per meter squared (Wm(-2)). C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Lee, RB (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 377 EP 388 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700035 ER PT S AU Bruegge, CJ Abdou, WA Chrien, NL Gaitley, BJ AF Bruegge, CJ Abdou, WA Chrien, NL Gaitley, BJ BE Barnes, WL TI AirMISR spectral and radiometric performance studies SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE AB An Airborne Multi-angle Imaging SpectroRadiometer (AirMISR) instrument has been developed to assist in validation of the Earth Observing System (EOS) MISR experiment. The airborne instrument is built to the same performance specifications as MISR. Both instruments view the earth at nine discrete view angles, provide data products which are radiance scaled to Systeme International (SI) units, registered among the view angles, and geolocated. Whereas on-orbit MISR will acquire a global data set every nine days, the aircraft version is restricted to a target size of 9 x 11 ion per aircraft run. AirMISR does, however, have the advantages of offering a means to testbed new mission procedures or camera designs, provide data sets which predate the MISR launch, and a means of returning to the laboratory to update the camera calibrations. This paper provides the AirMISR laboratory calibration results, as well as an example of a vicarious calibration exercise. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bruegge, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 431 EP 438 DI 10.1117/12.325648 PG 8 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700041 ER PT S AU West, RD Tsai, WY Granger, JL Daffer, WH AF West, RD Tsai, WY Granger, JL Daffer, WH BE Barnes, WL TI Calibration of the NASA Scatterometer using a ground calibration station SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE NSCAT; scatterometer; radar; calibration AB To aid in calibrating and monitoring the performance of the NASA scatterometer (NSCAT), a calibration ground station (CGS) was operated in White Sands, New Mexico from mid November 1996 through February 1997. The CGS was used to verify the proper operation of the NSCAT system including transmit power, frequency, pulse width, and receiver gain. It was also used to track spacecraft attitude variation, and to measure the antenna gain balance between different beams. This paper will describe the basic operation of the CGS, and the principle results obtained during the calibration period. The CGS is a transmit/receive system which was used to record pulses from NSCAT, and to transmit pulses back to NSCAT. The CGS data was synchronized with NSCAT telemetry, and processed for timing, frequency, and gain information. These results were then compared with the values expected using the nominal pre-launch calibration data. Timing discrepancies indicated significant spacecraft attitude variations beyond the values reported in telemetry. Gain discrepancies showed a small ascending/descending difference. The cause of this difference (NSCAT or the CGS) is not clear at this time. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP West, RD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 450 EP 459 DI 10.1117/12.325651 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700043 ER PT S AU Chan, PH AF Chan, PH BE Barnes, WL TI A business model for science data centers SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE product segmentation; customization; solution driven; consumption chain AB Conventionally, science data centers are supply driven-what they do and how they do it are determined entirely by what data sets they hold. The DAAC was no different. Between 1994 and 1997, the DAAC reinvented itself by reexamining its customers, changing the focus from supply driven to demand driven and achieved breakthrough results. This is the "business model" for science data centers. This article describes the DAAC's business model and the supply-driven data management practices. C1 NASA, Goddard Space Flight Ctr, Distributed Act Archive Ctr, Greenbelt, MD 20771 USA. RP Chan, PH (reprint author), NASA, Goddard Space Flight Ctr, Distributed Act Archive Ctr, Code 902, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 516 EP 521 DI 10.1117/12.325657 PG 6 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700049 ER PT S AU Lutz, B AF Lutz, B BE Barnes, WL TI Development of EOS quality assessment (QA) methodology and EOSDIS' support for QA SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE DE quality assessment; quality assurance; QA; quality control; EOS; EOSDIS AB A desirable feature of scientific data systems is that suspect and bad data be identified before release to the user community. This is a challenging task within the NASA Earth Observing System (EOS), due to the large volume and the complexity of data produced and the near real time mode between data production and distribution. The EOS Data and Information System (EOSDIS) provides the computing and network facilities, to support the generation and archival of data products from EOS satellites. EOS Quality Assessment (QA) methodology integrates a) the automated detection of certain types of suspect data, b) the capability of EOSDIS to alert the instrument team scientists and processing facility personnel to suspect data, c) the extraction of this data from the archives for QA purposes and the subsequent storage of QA results within EOSDIS, and d) the organization, archival and display of all of these QA results in a user-friendly format for the user community. Development of EOS QA methodology is described through discussions of the organization of QA information within the EOSDIS database, the components of operational QA, suggestions of how users may exploit the provided QA parameters and the support EOSDIS will provide users in utilizing QA information. C1 Raytheon STX Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lutz, B (reprint author), Raytheon STX Corp, Goddard Space Flight Ctr, Code 423, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 531 EP 540 DI 10.1117/12.325659 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700051 ER PT S AU Dehghani, N AF Dehghani, N BE Barnes, WL TI The ASTER Emergency Backup System SO EARTH OBSERVING SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Earth Observing Systems III CY JUL 19-21, 1998 CL SAN DIEGO, CA SP SPIE AB The ASTER Emergency Backup System (AEBS) provides limited post AM-1 platform launch capability for data ingest, processing and distribution of ASTER level 1 and level 2 products to the ASTER Science Team. This system is designed based on a request from the Goddard Space Flight Center's (GSFC) Earth Science Data and Information System (ESDIS, part of the Mission to Planet Earth) Project Manager when the Earth Observing System Data and Information System (EOSDIS) Core System (ECS) contractor slipped delivery schedules. The AEBS provides the capability to ingest, archive, and catalog ASTER level 1A and level 1B scenes from Japan at the EROS Data Center (EDC) Distributed Active Archive Center (DAAC) in Sioux Falls, South Dakota. Capability is provided to synchronize the level 1A and level 1B catalog database at EDC and the level 1A and level 1B catalog database at the Science Computing Facility (SCF) at the Jet Propulsion Laboratory (JPL) in Pasadena, California. The AEBS provides a simple search and order of level 1A and level 1B catalog at the JPL SCF to the ASTER Science Team, and provides the capability to generate and distribute ASTER level 2 products to the ASTER Science Team. The AEBS allows for automatic QA of products on a routine basis. Manual QA is performed at the discretion of the ASTER Science Team Leader at JPL SCF. This paper discusses the international aspect of the ASTER project by specifying data flow among Japan, the EDC DAAC, the JPL SCF, The Goddard Space Flight Center (GSFC), and the ASTER Science Team. A discussion of the design of the archive and catalog systems at EDC DAAC and at JPL SCF is also provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dehghani, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2894-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3439 BP 553 EP 559 DI 10.1117/12.325661 PG 7 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BL85V UT WOS:000076961700053 ER PT J AU Tobita, M Fujiwara, S Ozawa, S Rosen, PA Fielding, EJ Werner, CL Murakami, M Nakagawa, H Nitta, K Murakami, M AF Tobita, M Fujiwara, S Ozawa, S Rosen, PA Fielding, EJ Werner, CL Murakami, M Nakagawa, H Nitta, K Murakami, M TI Deformation of the 1995 North Sakhalin earthquake detected by JERS-1/SAR interferometry SO EARTH PLANETS AND SPACE LA English DT Article ID RADAR INTERFEROMETRY; SURFACE DEFORMATION AB We present a map of the coseismic displacement field resulting from the North Sakhalin, Russia, May 28, 1995, earthquake. Raw radar signal data from the JERS-1 synthetic aperture radar Instrument acquired in 28 April, 11 June, 25 July, and 7 September 1995 are used to generate a high-resolution, wide area map of the displacements by the two-pass differential interferometry method. The interferogram shows that an area of 60 km (EW) by 80 km (NS) experienced crustal deformations. The slip mechanism with fine structure is inverted using the displacement field of the SAR interferogram. This inversion of the SAR interferogram shows, 1) the rupture area extends to the south of the southernmost rupture trace on the surface, 2) slip varies from one to seven meters from the south to the northern part on the fault plane. A theoretical fringe pattern from the model of the earthquake motion matches the observations closely. We generate a full sce:ne digital elevation model (DEM) by JERS-1 SAR interferometry and synthesize a four-pass interferogram. Comparison of the differential interferometry between the four-pass and two-pass interferograms shows that they are very similar and the both methods are reliable to show surface displacements using JERS-1 SAR. Correlation study of the Sakhalin interferograms indicates that low surface temperatures, below the freezing point, reduced the correlation probably because a freeze would alter the dielectric constant of the surface. In these Sakhalin interferograms, we find few spurious fringes due to the usual heterogeneous distribution of weather-related atmospheric and surface conditions, probably because of the low temperatures. We also present a map of the postseismic displacement field with the SAR interferometry. C1 Geog Survey Inst, Tsukuba, Ibaraki 3050811, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tobita, M (reprint author), Geog Survey Inst, Kitasato 1, Tsukuba, Ibaraki 3050811, Japan. EM tobita@gsi-mc.go.jp RI Fielding, Eric/A-1288-2007 OI Fielding, Eric/0000-0002-6648-8067 NR 19 TC 24 Z9 29 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 1998 VL 50 IS 4 BP 313 EP 325 PG 13 WC Geosciences, Multidisciplinary SC Geology GA ZR406 UT WOS:000073972400002 ER PT J AU Ootsubo, T Onaka, T Yamamura, I Tanabe, T Roellig, TL Chan, KW Matsumoto, T AF Ootsubo, T Onaka, T Yamamura, I Tanabe, T Roellig, TL Chan, KW Matsumoto, T TI IRTS observation of the mid-infrared spectrum of the zodiacal emission SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Meeting on Zodiacal Cloud Sciences CY SEP, 1997 CL KOBE UNIV, KOBE, JAPAN HO KOBE UNIV ID MIDINFRARED SPECTROMETER; LIGHT; DUST; MISSION AB We present the mid-infrared spectrum (3-12 mu m) of the zodiacal emission obtained by the Infrared Telescope in Space (IRTS), the first Japanese cryogenically cooled orbital infrared telescope. The Near-Infrared Spectrometer (NIRS) on board IRTS provided the spectrum of 3-4 mu m, while that of 4.5-11.7 mu m has been observed by the Mid-Infrared Spectrometer (MIRS), In this paper we present the data reduction and results of the observations by MIRS. Spectra of the background emission at high galactic latitudes (\b\ > 30 degrees) have been extracted from the MIRS observations by excluding point sources. The observed sky brightness has a clear dependence on the ecliptic latitude, indicating that the zodiacal emission dominates in the mid-infrared sky brightness, On the other hand, the spectral shape does not show any appreciable dependence on the ecliptic latitude for beta = 0 degrees-75 degrees. The spectrum combining the NIRS and MIRS observations can be fitted by a grey body radiation at 250 K, but excess emission is seen in the 3-6 mu m range. Alternatively, the spectrum of the zodiacal emission can be reproduced fairly well by a grey body at 280 K with an excess around 10 mu m. In this case the excess may be attributed to a silicate emission band. Other than these excesses, no spectral features above the 10% level are seen in the MIRS spectrum. C1 Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Fac Sci, Inst Astron, Tokyo 1818588, Japan. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. SRON, NL-9700 AV Groningen, Netherlands. RP Ootsubo, T (reprint author), Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. NR 23 TC 15 Z9 15 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 1998 VL 50 IS 6-7 BP 507 EP 511 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 117PB UT WOS:000075789900009 ER PT J AU Gor'kavyi, N Ozernoy, L Mather, J Taidakova, T AF Gor'kavyi, N Ozernoy, L Mather, J Taidakova, T TI Structure of the zodiacal cloud: new analytical and numerical solutions SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Meeting on Zodiacal Cloud Sciences CY SEP, 1997 CL KOBE UNIV, KOBE, JAPAN HO KOBE UNIV ID POYNTING-ROBERTSON DRAG; INTERPLANETARY DUST; DYNAMICAL EVOLUTION; RING; EARTH AB Recent results of analytical and numerical modelling of the interplanetary dust (IPD) distribution are described. They have been obtained with a new techniques employing the continuity equation written in the space of orbital coordinates. A 3-D structure and the corresponding 2-D slices for the IPD cloud governed by the Poynting-Robertson drag are computed in the framework of our 'reference model', accounting for almost all of the known major sources of dust (5000 asteroids and 217 comets). We discuss also the origin and structure of the 'dust bands' and the resonant ring near Earth. C1 Crimean Astrophys Observ, Crimea, Ukraine. George Mason Univ, Fairfax, VA 22030 USA. NASA, GSFC, Greenbelt, MD USA. RP Gor'kavyi, N (reprint author), Crimean Astrophys Observ, Crimea, Ukraine. NR 19 TC 5 Z9 5 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 1998 VL 50 IS 6-7 BP 539 EP 544 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 117PB UT WOS:000075789900013 ER PT J AU Jenniskens, P AF Jenniskens, P TI On the dynamics of meteoroid streams SO EARTH PLANETS AND SPACE LA English DT Article; Proceedings Paper CT Meeting on Zodiacal Cloud Sciences CY SEP, 1997 CL KOBE UNIV, KOBE, JAPAN HO KOBE UNIV ID COMETARY DUST TRAILS; RADAR OBSERVATIONS; C/1996 B2; SHOWER; OUTBURSTS; EJECTION; ORBITS; STORMS; PARTICLES; HYAKUTAKE AB Zodiacal dust evolves from cometary debris through a stage called a meteoroid stream. Meteoroid streams produce meteor showers if a node of the stream is near 1 AU. On occasion, Earth encounters a stream of meteoroids that has not dispersed wide enough to be detected annually. A rare and often short lived enhancement of rates is observed during which the meteors typically have smaller radiant dispersion and sometimes anomalous fragmentation properties and end heights. Here, we summarize recent observations of these meteor outbursts and discuss how the results constrain our knowledge of the early stages of meteoroid stream formation. These stages tie meteoroid streams to cometary dust trails and are an important step in the dynamical evolution from cometary to zodiacal dust. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 79 TC 22 Z9 22 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 1998 VL 50 IS 6-7 BP 555 EP 567 PG 13 WC Geosciences, Multidisciplinary SC Geology GA 117PB UT WOS:000075789900016 ER PT J AU Niemann, HB Harpold, DN Feng, S Kasprzak, WT Way, SH Atreya, SK Block, B Carignan, GR Donahue, TM Nagy, AF Bougher, SW Hunten, DM Owen, TC Bauer, SJ Hayakawa, HJ Mukai, T Miura, YN Sugiura, N AF Niemann, HB Harpold, DN Feng, S Kasprzak, WT Way, SH Atreya, SK Block, B Carignan, GR Donahue, TM Nagy, AF Bougher, SW Hunten, DM Owen, TC Bauer, SJ Hayakawa, HJ Mukai, T Miura, YN Sugiura, N TI The Planet-B neutral gas mass spectrometer SO EARTH PLANETS AND SPACE LA English DT Article ID TERRESTRIAL PLANETS; VENUS; MARS; THERMOSPHERE AB The Planet-B neutral gas mass spectrometer is designed for in-situ measurements of the gas composition in the upper atmosphere of Mars. The sensor uses a dual frequency quadrupole mass analyzer with a mass range of 1-60 amu (atomic mass units) and two electron multipliers to cover the dynamic range required. The ion source, which is collinear with the analyzer, operates in two different modes: 1) a closed source mode measuring non-surface reactive neutral species that have thermally accommodated to the gas inlet walls; and 2) an open source mode measuring chemically surface active species by direct beaming with no surface collisions. The in-line Retarding Potential Analysis (RPA) system selects the mode of operation. An onboard Field Programmable Gate Array (FPGA) is used to control the instrument operating parameters in accordance with pre-programmed sequences and to package the telemetry data. The sensor is sealed and maintained in a vacuum prior to launch and will be opened to the environment of Mars after orbit insertion. Measurements of He, N, O, CO, N-2, NO, O-2, Ar, and CO2 will be done at periapsis and the data will be used to determine the variation of the neutral atmosphere density and temperature with altitude, local solar time and season. Measurements are possible from 130-140 km to 500 km depending on the gas species, chemical background, and instrument measurement mode. The data will contribute to the studies of thermosphere energetics, lower atmosphere meteorology (e.g. dust storms) and serve as a resource for studies of the interaction of the upper atmosphere with the solar wind. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Graz Univ, Graz, Austria. Inst Space & Astronaut Sci, Tokyo 153, Japan. Univ Tokyo, Tokyo, Japan. RP Niemann, HB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Sugiura, Naoji/A-1855-2009; Bougher, Stephen/C-1913-2013; Harpold, Dan/I-3345-2013 OI Bougher, Stephen/0000-0002-4178-2729; NR 24 TC 6 Z9 7 U1 0 U2 3 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 1998 VL 50 IS 9 BP 785 EP 792 PG 8 WC Geosciences, Multidisciplinary SC Geology GA 135CE UT WOS:000076781900007 ER PT B AU Parry, ML Rosenzweig, C Hossell, JE Jones, P Rehmam, T Tranter, RB Marsh, JS Taylor, JC AF Parry, ML Rosenzweig, C Hossell, JE Jones, P Rehmam, T Tranter, RB Marsh, JS Taylor, JC BE Schellnhuber, HJ Wenzel, V TI Climate change and land use: Global and regional analyses SO EARTH SYSTEMS ANALYSIS: INTEGRATING SCIENCE FOR SUSTAINABILITY - COMPLEMENTED RESULTS OF A SYMPOSIUM LA English DT Proceedings Paper CT Symposium on Earth System Analysis CY 1994 CL POTSDAM, GERMANY SP Potsdam Inst ID CARBON-DIOXIDE AB The potential effects of climate change on agricultural land use in any given region are likely to stem as much from the response of the world food system to global climate change as to specific changes in climate in that region. To achieve this level of analysis requires evaluation of inputs at the regional level but within a global price environment. This, in turn, requires the development of a hierarchy of land use/climate models. In this paper Ive employ results of a global analysis of the sensitivity of world food prices to climate change, using these as inputs to a regional land use allocation model, in order to evaluate the potential effects of climate change on regional patterns of land use. There are two components to the global estimation: Firstly, the estimation of potential changes in national grain crop yields using crop models and a decision support system. Secondly the estimation of world food trade responses. The yield changes were used as inputs into a world food trade model, the Basic Linked System (BLS). Outputs from simulations by the BLS provided information on global food production potential, and food prices. The second part of the paper illustrates how an analysis of these two global elements (crop yields and food prices) can be made in order to evaluate their integrated effect in land use. A case study is used to illustrate the process; in this instance, for England and Wales using a Land Use Allocation Model and manipulating it in the context of a) global price changes due to climate and b) changes in yield potential in England and Wales due to climate. The combination of price and yield potential is used to calculate the highest value use for each of 250 000 1-km(2) cells of land in England and Wales for a future economic environment in 2060 (without climate change) and then for that same environment with climate change. The difference provides an estimated effect of climate change. C1 Columbia Univ, Goddard Inst Space Studies, New York, NY 10027 USA. RP Parry, ML (reprint author), Columbia Univ, Goddard Inst Space Studies, New York, NY 10027 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-58017-4 PY 1998 BP 251 EP 272 PG 4 WC Geosciences, Multidisciplinary SC Geology GA BM52U UT WOS:000079024500008 ER PT S AU Cumpston, BH Ehrlich, JE Erskine, LL Heikal, AA Hu, ZY Lee, LYS Levin, MD Marder, SR McCord, DJ Perry, JW Rockel, H Rumi, M Wu, XL AF Cumpston, BH Ehrlich, JE Erskine, LL Heikal, AA Hu, ZY Lee, LYS Levin, MD Marder, SR McCord, DJ Perry, JW Rockel, H Rumi, M Wu, XL BE Reynolds, JR Jen, AKY Rubner, MF Chiang, LY Dalton, LR TI New photopolymers based on two-photon absorbing chromophores and application to three-dimensional microfabrication and optical storage SO ELECTRICAL, OPTICAL, AND MAGNETIC PROPERTIES OF ORGANIC SOLID-STATE MATERIALS IV SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Electrical, Optical, and Magnetic Properties of Organic Solid-State Materials IV CY DEC 01-05, 1997 CL BOSTON, MA SP Mat Res Soc, Int Specialty Prod, Natl Taiwan Univ, Taiwan Four Pillars, Taiwan President Enterprises, United Microelectr Corp AB Molecules exhibiting strong two-photon absorption hold great potential for a wide range of applications including two-photon fluorescence imaging, three-dimensional (3D) optical data storage, and 3D microfabrication. We have observed two-photon absorptivities as high as 1500x10(-50) cm(4) s/photon in bis-donor diphenylpolyene derivatives that are correlated to simultaneous charge transfer from the end groups to the polyene bridge in the molecule. Many of these molecules are also excellent photoexcitable electron donors that can initiate charge-transfer reactions with acrylate monomers. Marcus theory is used to describe the efficiency of these charge-transfer reactions. Polymerization rates have also been measured and we show that these two-photon chromophores display increased sensitivity and recording speed over conventional UV photo-initiators. The fabrication of complex, three-dimensional structures by two-photon polymerization is demonstrated and discussed in the context of advanced photonic applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cumpston, BH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Rumi, Mariacristina/C-9474-2009; Perry, Joseph/B-7191-2011 OI Rumi, Mariacristina/0000-0002-4597-9617; Perry, Joseph/0000-0003-1101-7337 NR 0 TC 9 Z9 10 U1 0 U2 4 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-393-2 J9 MATER RES SOC SYMP P PY 1998 VL 488 BP 217 EP 225 PG 3 WC Chemistry, Applied; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Chemistry; Engineering; Materials Science; Optics GA BL06U UT WOS:000074149700029 ER PT B AU Garg, A Noebe, RD Locci, IE Darolia, R AF Garg, A Noebe, RD Locci, IE Darolia, R BE Benavides, HAC Yacaman, MJ TI Effect of Si on the microstructure and stability of different phases in a NiAl-Hf single-crystal alloy SO ELECTRON MICROSCOPY 1998, VOL 2: MATERIALS SCIENCE 1 LA English DT Proceedings Paper CT 14th International Congress on Electron Microscopy CY AUG 31-SEP 04, 1998 CL CANCUN, MEXICO SP Mexican Soc Microscopy, Consejo Nacl Ciencia & Tecnol, Inst Nacl Invest Nucl, Univ Autonoma Estado Mexico, Univ Veracruzana, Ctr Invest & Estudios Avanzados, Univ Nacl Autonoma Mexico, Ctr Invest Mat Avanzados, Inst Politecn Nacl, Univ Autonoma Nuevo Leon C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Garg, A (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0565-7 PY 1998 BP 151 EP 152 PG 2 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Microscopy SC Materials Science; Microscopy GA BL87H UT WOS:000077019900074 ER PT B AU Locci, IE Brady, MP MacKay, RA Smith, JW AF Locci, IE Brady, MP MacKay, RA Smith, JW BE Benavides, HAC Yacaman, MJ TI Long term oxidation of Ti-48Al-2Cr-2Nb SO ELECTRON MICROSCOPY 1998, VOL 2: MATERIALS SCIENCE 1 LA English DT Proceedings Paper CT 14th International Congress on Electron Microscopy CY AUG 31-SEP 04, 1998 CL CANCUN, MEXICO SP Mexican Soc Microscopy, Consejo Nacl Ciencia & Tecnol, Inst Nacl Invest Nucl, Univ Autonoma Estado Mexico, Univ Veracruzana, Ctr Invest & Estudios Avanzados, Univ Nacl Autonoma Mexico, Ctr Invest Mat Avanzados, Inst Politecn Nacl, Univ Autonoma Nuevo Leon C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Locci, IE (reprint author), NASA, Lewis Res Ctr, M-S 49-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0565-7 PY 1998 BP 201 EP 202 PG 2 WC Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Microscopy SC Materials Science; Microscopy GA BL87H UT WOS:000077019900099 ER PT B AU Leon, R Stevens-Kalceff, M Zou, J Lobo, C Cockayne, DJH AF Leon, R Stevens-Kalceff, M Zou, J Lobo, C Cockayne, DJH BE Benavides, HAC Yacaman, MJ TI Ordering, tunability, and stability in the formation of semiconductor quantum dots SO ELECTRON MICROSCOPY 1998, VOL 3: MATERIALS SCIENCE 2 LA English DT Proceedings Paper CT 14th International Congress on Electron Microscopy CY AUG 31-SEP 04, 1998 CL CANCUN, MEXICO SP Mexican Soc Microscopy, Consejo Nacl Ciencia & Tecnol, Inst Nacl Invest Nucl, Univ Autonoma Estado Mexico, Univ Veracruzana, Ctr Invest & Estudios Avanzados, Univ Nacl Autonoma Mexico, Ctr Invest Mat Avanzados, Inst Politecn Nacl, Univ Autonoma Nuevo Leon C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Leon, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Zou, Jin/B-3183-2009; Lobo, Charlene/G-5003-2011 OI Zou, Jin/0000-0001-9435-8043; Lobo, Charlene/0000-0002-2746-1363 NR 0 TC 0 Z9 0 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0566-5 PY 1998 BP 377 EP 378 PG 2 WC Chemistry, Physical; Materials Science, Multidisciplinary; Materials Science, Biomaterials; Microscopy SC Chemistry; Materials Science; Microscopy GA BL87J UT WOS:000077020300181 ER EF